Clinical Focus

  • Anesthesia for Liver Transplantation
  • Neuroanesthesia
  • Anesthesia
  • Perioperative Recovery

Academic Appointments

Administrative Appointments

  • Vice Chair Strategy and Initiatives, Stanford University School of Medicine, Department of Anesthesiology (2022 - Present)
  • Director of CTA Strategic Initiatives and Operations, Stanford University School of Medicine (2019 - 2022)
  • CVH Operations Leadership Group, Stanford University School of Medicine, CV Health Service Line (2019 - 2022)
  • Appointments and Promotions Committee, Stanford University School of Medicine (2015 - 2021)
  • Finance Committee, Stanford University School of Medicine, Department of Anesthesiology (2019 - Present)
  • Governance Committee, Stanford University School of Medicine, Department of Anesthesiology (2019 - Present)

Professional Education

  • Board Certification: Swiss Medical Federation FMH, Anesthesia (1993)
  • Residency: University of Bern - Switzerland (1994) Switzerland
  • Residency: Regionalspital Burgdorf (1990) Switzerland
  • Medical Education: Berne University School of Medicine (1987) Switzerland

Current Research and Scholarly Interests

We investigate the biological and clinical characteristics that drive resilience in humans using surgery as an interventional injury model. The capacity to recover from injury, or alternatively, suffer from dire consequences, is at the very core of human health. The modern armamentarium in the natural, clinical, and computational sciences allows for an unprecedented exploration of the question as to what constitutes human fitness. Our efforts employ sophisticated multi-omic and computational approaches. Gained knowledge will permit individual patient consultation and management in the field of anesthesiology and perioperative care. Some patients may benefit most from complex and invasive surgical procedures, while others may be better served by minimally invasive or none-surgical interventions. Furthermore, novel strategies are on the horizon to render vulnerable patients fit for surgery with pre-surgical and perioperative interventions.

Clinical Trials

  • Detection of Immune Changes as a Result of Surgical Trauma in Human Subject Recruiting

    Surgical trauma triggers a massive inflammatory response. Over time, both the innate and adaptive branches of the immune system are affected by surgical trauma. The purpose of this study to characterize the cellular and molecular mechanisms immune response to surgical trauma. Additionally, detailed information about patients' recovery profile will be recorded over a period of 6 weeks, with the eventual goal of linking immune responses to recovery profiles.

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  • Immune Modulation by Enhanced vs Standard Prehabilitation Program Before Major Surgery Recruiting

    Over 30 million surgeries are performed annually in the US. Up to 30% of surgical patients experience delayed surgical recovery, marked by prolonged post-surgical pain, opioid consumption, and functional impairment, which contributes $8 billion annually to US health care costs. Novel interventions that improve the resolution of pain, minimize opioid exposure, and accelerate functional recovery after surgery are urgently needed. Multi-modal pre-operative optimization programs (or "prehab") integrating exercise, nutrition, and stress reduction have been shown to safely and effectively improve outcomes after surgery. However, no objective biological markers assess prehab effectiveness and are able to tailor prehab programs to individual patients. Surgery is a profound immunological perturbation, during which a complex network of innate and adaptive immune cells is mobilized to organize the recovery process of wound healing, tissue repair, and pain resolution. As such, the in-depth assessment of a patient's immune system before surgery is a promising approach to tailor prehab programs to modifiable biological markers associated with surgical recovery. The primary goal of this clinical trial is to determine the effect of a personalized prehab program on patients immunological status before surgery.

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  • A Human In-vivo Model for the Detection of Inflammatory and Nociceptive Biomarkers Not Recruiting

    This study aims to establish a novel approach assisting the rational development of analgesic and anti-inflammatory drugs. In a first step we will test in healthy human volunteers whether proteins mediating inflammation and pain can be detected in an experimentally induced inflammatory skin lesion. Fluids that will be used to detect such proteins will be collected from the inflamed skin site via small porous catheters. We wish to establish the expression pattern of different proteins and correlate it with various tests assessing pain.

    Stanford is currently not accepting patients for this trial. For more information, please contact Martin Angst, (650) 498 - 5109.

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  • A Study to Evaluate the Effect of GRF6021 on Postoperative Recovery Following Primary Hip or Knee Arthroplasty Not Recruiting

    This study will evaluate the safety, tolerability and effect of GRF6021 on clinical recovery parameters in participants undergoing primary hip or knee arthroplasty.

    Stanford is currently not accepting patients for this trial.

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  • Cocoa Flavanols for Modulating Immune Response and Accelerating Recovery Not Recruiting

    This double-blind, placebo-controlled proof-of-concept clinical trial is intended to demonstrate that preemptive oral administration of cocoa flavanol for five days before surgery will attenuate the surgery-evoked increase of HMGB1 in blood plasma and NFkB signaling in innate immune cells shortly after surgery. A secondary aim is to capture preliminary patient-centered outcomes data and relate these outcomes to the intake of oral cocoa flavanol and surgery-evoked activation of the HMGB1-NFkB signaling axis. Participants will be randomized to receive either an over the counter supplement containing cocoa flavanols, or placebo, for 5 days before surgery.

    Stanford is currently not accepting patients for this trial. For more information, please contact Martha S Tingle, RN, 650-724-2742.

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  • Effects of a Peripheral Nerve Block on Biomarkers of Pain and Inflammation Not Recruiting

    The purpose of this study is to determine the effect of a local anesthetic nerve block on markers of inflammation and pain after a sunburn. This is important because it may provide information regarding the way that nerve blocks help with the treatment of pain and in particular provide preemptive analgesia.

    Stanford is currently not accepting patients for this trial. For more information, please contact Martha Tingle, (650) 724 - 2742.

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  • Evaluation of Immune Signaling Networks in Healthy Human Volunteers Not Recruiting

    The purpose of this study is to better understand whether and to what extent the activity of immune cells in blood varies over time under normal conditions as assessed in healthy subjects. Results of this study will provide the foundation for helping us evaluate changes in immune cell activities in response to surgery and drugs used in anesthesia. The overall purpose of our research is to understand immune health in the context of anesthesia and surgery.

    Stanford is currently not accepting patients for this trial.

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  • Evaluation of Propranolol's Effect on Pain and Inflammation. Not Recruiting

    Previous studies have shown that the beta-adrenergic system plays a role in processing pain and the expression of hyperalgesia. Recent studies have investigated the analgesic effects, and potential anti-hyperalgesic effects (using a model of opioid induced (OIH) hyperalgesia) of propranolol, a beta adrenergic antagonist. We plan to further investigate the analgesic effects, and the potential anti inflammatory effects, of propranolol and compare those effects to alfentanil, an opioid of known effect, and placebo

    Stanford is currently not accepting patients for this trial. For more information, please contact Martha Tingle, (650) 724 - 2742.

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  • Heritability of Opioid Effects: A Twin Study Not Recruiting

    Proposed twin study will test to what degree inter-individual differences in pain sensitivity and amount of pain relief in response to opioid therapy are inherited or alternatively, are due to environmental factors. This knowledge is important to guide future studies trying to explain such inter-individual differences. For example, finding that differences are largely due to environmental factors would discourage genomic studies and emphasize epidemiological studies.

    Stanford is currently not accepting patients for this trial. For more information, please contact Martha Tingle, (650) 724 - 2742.

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  • Immune-modulation Effects of an Arginine Rich Nutritional Supplement in Surgical Patients Not Recruiting

    The primary objective of this study is to characterize the immune-modulatory effects of arginine-rich nutritional supplements in patients undergoing surgery. Numerical and functional changes of all circulating immune cells will be assessed with mass cytometry.

    Stanford is currently not accepting patients for this trial. For more information, please contact Julian Silva, MA, 650-724-9341.

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  • Optimization of Time-of-Flight Mass Cytometry (CyTOF) Analysis for Evaluation of Immune Changes Following Surgery Not Recruiting

    Surgical trauma triggers a massive inflammatory response. Over time, both the innate and adaptive branches of the immune system are affected by surgical trauma. The purpose of this study is to use a single cell flow cytometry approach to characterize the cellular and molecular mechanisms involved in the inflammatory response to surgical trauma.

    Stanford is currently not accepting patients for this trial.

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  • Study of Experimental Models of Pain and Inflammation. Not Recruiting

    The experimental pain model studied in this proposal show characteristics of an inflamed wound with a pro-inflammatory response. This study will help discover candidate genetic and/or proteomic pain biomarkers that could provide objective and mechanism based tests to diagnose, monitor or quantify pain. We also hope to determine the measurable effects of a known non-steroidal anti-inflammatory drug (NSAID) on biomarkers of pain and inflammation.

    Stanford is currently not accepting patients for this trial. For more information, please contact Martin Angst, (650) 498 - 5109.

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2023-24 Courses

All Publications

  • Corrigendum: Advances and potential of omics studies for understanding the development of food allergy. Frontiers in allergy Sindher, S. B., Chin, A. R., Aghaeepour, N., Prince, L., Maecker, H., Shaw, G. M., Stevenson, D., Nadeau, K. C., Snyder, M., Khatri, P., Boyd, S. D., Winn, V. D., Angst, M. S., Chinthrajah, R. S. 2024; 5: 1373485


    [This corrects the article DOI: 10.3389/falgy.2023.1149008.].

    View details for DOI 10.3389/falgy.2024.1373485

    View details for PubMedID 38464397

    View details for PubMedCentralID PMC10921899

  • Discovery of sparse, reliable omic biomarkers with Stabl. Nature biotechnology Hédou, J., Marić, I., Bellan, G., Einhaus, J., Gaudillière, D. K., Ladant, F. X., Verdonk, F., Stelzer, I. A., Feyaerts, D., Tsai, A. S., Ganio, E. A., Sabayev, M., Gillard, J., Amar, J., Cambriel, A., Oskotsky, T. T., Roldan, A., Golob, J. L., Sirota, M., Bonham, T. A., Sato, M., Diop, M., Durand, X., Angst, M. S., Stevenson, D. K., Aghaeepour, N., Montanari, A., Gaudillière, B. 2024


    Adoption of high-content omic technologies in clinical studies, coupled with computational methods, has yielded an abundance of candidate biomarkers. However, translating such findings into bona fide clinical biomarkers remains challenging. To facilitate this process, we introduce Stabl, a general machine learning method that identifies a sparse, reliable set of biomarkers by integrating noise injection and a data-driven signal-to-noise threshold into multivariable predictive modeling. Evaluation of Stabl on synthetic datasets and five independent clinical studies demonstrates improved biomarker sparsity and reliability compared to commonly used sparsity-promoting regularization methods while maintaining predictive performance; it distills datasets containing 1,400-35,000 features down to 4-34 candidate biomarkers. Stabl extends to multi-omic integration tasks, enabling biological interpretation of complex predictive models, as it hones in on a shortlist of proteomic, metabolomic and cytometric events predicting labor onset, microbial biomarkers of pre-term birth and a pre-operative immune signature of post-surgical infections. Stabl is available at .

    View details for DOI 10.1038/s41587-023-02033-x

    View details for PubMedID 38168992

    View details for PubMedCentralID 7003173

  • Deep representation learning identifies associations between physical activity and sleep patterns during pregnancy and prematurity. NPJ digital medicine Ravindra, N. G., Espinosa, C., Berson, E., Phongpreecha, T., Zhao, P., Becker, M., Chang, A. L., Shome, S., Marić, I., De Francesco, D., Mataraso, S., Saarunya, G., Thuraiappah, M., Xue, L., Gaudillière, B., Angst, M. S., Shaw, G. M., Herzog, E. D., Stevenson, D. K., England, S. K., Aghaeepour, N. 2023; 6 (1): 171


    Preterm birth (PTB) is the leading cause of infant mortality globally. Research has focused on developing predictive models for PTB without prioritizing cost-effective interventions. Physical activity and sleep present unique opportunities for interventions in low- and middle-income populations (LMICs). However, objective measurement of physical activity and sleep remains challenging and self-reported metrics suffer from low-resolution and accuracy. In this study, we use physical activity data collected using a wearable device comprising over 181,944 h of data across N = 1083 patients. Using a new state-of-the art deep learning time-series classification architecture, we develop a 'clock' of healthy dynamics during pregnancy by using gestational age (GA) as a surrogate for progression of pregnancy. We also develop novel interpretability algorithms that integrate unsupervised clustering, model error analysis, feature attribution, and automated actigraphy analysis, allowing for model interpretation with respect to sleep, activity, and clinical variables. Our model performs significantly better than 7 other machine learning and AI methods for modeling the progression of pregnancy. We found that deviations from a normal 'clock' of physical activity and sleep changes during pregnancy are strongly associated with pregnancy outcomes. When our model underestimates GA, there are 0.52 fewer preterm births than expected (P = 1.01e - 67, permutation test) and when our model overestimates GA, there are 1.44 times (P = 2.82e - 39, permutation test) more preterm births than expected. Model error is negatively correlated with interdaily stability (P = 0.043, Spearman's), indicating that our model assigns a more advanced GA when an individual's daily rhythms are less precise. Supporting this, our model attributes higher importance to sleep periods in predicting higher-than-actual GA, relative to lower-than-actual GA (P = 1.01e - 21, Mann-Whitney U). Combining prediction and interpretability allows us to signal when activity behaviors alter the likelihood of preterm birth and advocates for the development of clinical decision support through passive monitoring and exercise habit and sleep recommendations, which can be easily implemented in LMICs.

    View details for DOI 10.1038/s41746-023-00911-x

    View details for PubMedID 37770643

    View details for PubMedCentralID 3796350

  • Variability and relative contribution of surgeon and anesthesia specific time components to total procedural time in cardiac surgery. The Journal of thoracic and cardiovascular surgery Vanneman, M. W., Thuraiappah, M., Feinstein, I., Fielding-Singh, V., Peterson, A., Kronenberg, S., Angst, M. S., Aghaeepour, N. 2023


    OBJECTIVES: Decreasing variability in time intensive tasks during cardiac surgery may reduce total procedural time, lower costs, reduce clinician burnout, and improve patient access. The relative contribution and variability of surgeon and anesthesia control times to total procedural time is unknown.METHODS: 669 patients undergoing coronary artery bypass graft surgery were enrolled. Using linear regression, we estimated adjusted surgeon and anesthesia control times controlling for patient and procedural covariates. The primary end point compared overall surgeon and anesthesia control times. The secondary end point compared the variability in adjusted surgeon and anesthesiologist control times. Sensitivity analyses quantified the relative importance of the specific surgeon and anesthesiologist in the adjusted linear models.RESULTS: The median surgeon control time was 4.1 hours (interquartile range: 3.4 to 4.9 hours) compared to a median anesthesia control time of 1.0 hours (interquartile range: 0.8 to 1.2 hours, p < 0.001). Using linear regression, the variability in adjusted surgeon control time amongst surgeons (range: 1.8 hours) was 3.5-fold greater than the variability in adjusted anesthesia control time amongst anesthesiologists (range: 0.5 hours, p < 0.001). The specific surgeon and anesthesiologist accounted for 50% of the explanatory power of the predictive model (p < 0.001).CONCLUSIONS: Surgeon control time variability is significantly greater than anesthesia control time variability and strongly associated with the surgeon performing the procedure. While these results suggest surgeon control time variability is an attractive operational target, further studies are needed to determine practitioner specific and modifiable attributes to reduce variability and improve efficiency.

    View details for DOI 10.1016/j.jtcvs.2023.08.011

    View details for PubMedID 37574007

  • Comparative predictive power of serum vs plasma proteomic signatures in feto-maternal medicine. AJOG global reports Espinosa, C., Ali, S. M., Khan, W., Khanam, R., Pervin, J., Price, J. T., Rahman, S., Hasan, T., Ahmed, S., Raqib, R., Rahman, M., Aktar, S., Nisar, M. I., Khalid, J., Dhingra, U., Dutta, A., Deb, S., Stringer, J. S., Wong, R. J., Shaw, G. M., Stevenson, D. K., Darmstadt, G. L., Gaudilliere, B., Baqui, A. H., Jehan, F., Rahman, A., Sazawal, S., Vwalika, B., Aghaeepour, N., Angst, M. S. 2023; 3 (3): 100244


    Blood proteins are frequently measured in serum or plasma, because they provide a wealth of information. Differences in the ex vivo processing of serum and plasma raise concerns that proteomic health and disease signatures derived from serum or plasma differ in content and quality. However, little is known about their respective power to predict feto-maternal health outcomes. Predictive power is a sentinel characteristic to determine the clinical use of biosignatures.This study aimed to compare the power of serum and plasma proteomic signatures to predict a physiological pregnancy outcome.Paired serum and plasma samples from 73 women were obtained from biorepositories of a multinational prospective cohort study on pregnancy outcomes. Gestational age at the time of sampling was the predicted outcome, because the proteomic signatures have been validated for such a prediction. Multivariate and cross-validated models were independently derived for serum and plasma proteins.A total of 1116 proteins were measured in 88 paired samples from 73 women with a highly multiplexed platform using proximity extension technology (Olink Proteomics Inc, Watertown, MA). The plasma proteomic signature showed a higher predictive power (R=0.64; confidence interval, 0.42-0.79; P=3.5×10-6) than the serum signature (R=0.45; confidence interval, 0.18-0.66; P=2.2×10-3). The serum signature was validated in plasma with a similar predictive power (R=0.58; confidence interval, 0.34-0.75; P=4.8×10-5), whereas the plasma signature was validated in serum with reduced predictive power (R=0.53; confidence interval, 0.27-0.72; P=2.6×10-4). Signature proteins largely overlapped in the serum and plasma, but the strength of association with gestational age was weaker for serum proteins.Findings suggest that serum proteomics are less informative than plasma proteomics. They are compatible with the view that the partial ex-vivo degradation and modification of serum proteins during sample processing are an underlying reason. The rationale for collecting and analyzing serum and plasma samples should be carefully considered when deriving proteomic biosignatures to ascertain that specimens of the highest scientific and clinical yield are processed. Findings suggest that plasma is the preferred matrix.

    View details for DOI 10.1016/j.xagr.2023.100244

    View details for PubMedID 37456144

    View details for PubMedCentralID PMC10339042

  • Multiomic signals associated with maternal epidemiological factors contributing to preterm birth in low- and middle-income countries. Science advances Espinosa, C. A., Khan, W., Khanam, R., Das, S., Khalid, J., Pervin, J., Kasaro, M. P., Contrepois, K., Chang, A. L., Phongpreecha, T., Michael, B., Ellenberger, M., Mehmood, U., Hotwani, A., Nizar, A., Kabir, F., Wong, R. J., Becker, M., Berson, E., Culos, A., De Francesco, D., Mataraso, S., Ravindra, N., Thuraiappah, M., Xenochristou, M., Stelzer, I. A., Marić, I., Dutta, A., Raqib, R., Ahmed, S., Rahman, S., Hasan, A. S., Ali, S. M., Juma, M. H., Rahman, M., Aktar, S., Deb, S., Price, J. T., Wise, P. H., Winn, V. D., Druzin, M. L., Gibbs, R. S., Darmstadt, G. L., Murray, J. C., Stringer, J. S., Gaudilliere, B., Snyder, M. P., Angst, M. S., Rahman, A., Baqui, A. H., Jehan, F., Nisar, M. I., Vwalika, B., Sazawal, S., Shaw, G. M., Stevenson, D. K., Aghaeepour, N. 2023; 9 (21): eade7692


    Preterm birth (PTB) is the leading cause of death in children under five, yet comprehensive studies are hindered by its multiple complex etiologies. Epidemiological associations between PTB and maternal characteristics have been previously described. This work used multiomic profiling and multivariate modeling to investigate the biological signatures of these characteristics. Maternal covariates were collected during pregnancy from 13,841 pregnant women across five sites. Plasma samples from 231 participants were analyzed to generate proteomic, metabolomic, and lipidomic datasets. Machine learning models showed robust performance for the prediction of PTB (AUROC = 0.70), time-to-delivery (r = 0.65), maternal age (r = 0.59), gravidity (r = 0.56), and BMI (r = 0.81). Time-to-delivery biological correlates included fetal-associated proteins (e.g., ALPP, AFP, and PGF) and immune proteins (e.g., PD-L1, CCL28, and LIFR). Maternal age negatively correlated with collagen COL9A1, gravidity with endothelial NOS and inflammatory chemokine CXCL13, and BMI with leptin and structural protein FABP4. These results provide an integrated view of epidemiological factors associated with PTB and identify biological signatures of clinical covariates affecting this disease.

    View details for DOI 10.1126/sciadv.ade7692

    View details for PubMedID 37224249

  • STABL Enables Reliable and Selective biomarker Discovery in Predictive Modeling of High Dimensional Omics Data Verdonk, F., Hedou, J., Maric, I., Bellan, G., Einhaus, J., Gaudilliere, D., Ladant, F., Stelzer, I., Feyaerts, D., Tsai, A., Bonham, A., Angst, M., Aghaeepour, N., Stevenson, D., Tibshirani, R., Gaudilliere, B. LIPPINCOTT WILLIAMS & WILKINS. 2023: 814-821
  • Large-scale correlation network construction for unraveling the coordination of complex biological systems. Nature computational science Becker, M., Nassar, H., Espinosa, C., Stelzer, I. A., Feyaerts, D., Berson, E., Bidoki, N. H., Chang, A. L., Saarunya, G., Culos, A., De Francesco, D., Fallahzadeh, R., Liu, Q., Kim, Y., Marić, I., Mataraso, S. J., Payrovnaziri, S. N., Phongpreecha, T., Ravindra, N. G., Stanley, N., Shome, S., Tan, Y., Thuraiappah, M., Xenochristou, M., Xue, L., Shaw, G., Stevenson, D., Angst, M. S., Gaudilliere, B., Aghaeepour, N. 2023; 3 (4): 346-359


    Advanced measurement and data storage technologies have enabled high-dimensional profiling of complex biological systems. For this, modern multiomics studies regularly produce datasets with hundreds of thousands of measurements per sample, enabling a new era of precision medicine. Correlation analysis is an important first step to gain deeper insights into the coordination and underlying processes of such complex systems. However, the construction of large correlation networks in modern high-dimensional datasets remains a major computational challenge owing to rapidly growing runtime and memory requirements. Here we address this challenge by introducing CorALS (Correlation Analysis of Large-scale (biological) Systems), an open-source framework for the construction and analysis of large-scale parametric as well as non-parametric correlation networks for high-dimensional biological data. It features off-the-shelf algorithms suitable for both personal and high-performance computers, enabling workflows and downstream analysis approaches. We illustrate the broad scope and potential of CorALS by exploring perspectives on complex biological processes in large-scale multiomics and single-cell studies.

    View details for DOI 10.1038/s43588-023-00429-y

    View details for PubMedID 38116462

    View details for PubMedCentralID PMC10727505

  • Advances and potential of omics studies for understanding the development of food allergy. Frontiers in allergy Sindher, S. B., Chin, A. R., Aghaeepour, N., Prince, L., Maecker, H., Shaw, G. M., Stevenson, D. K., Nadeau, K. C., Snyder, M., Khatri, P., Boyd, S. D., Winn, V. D., Angst, M. S., Chinthrajah, R. S. 2023; 4: 1149008


    The prevalence of food allergy continues to rise globally, carrying with it substantial safety, economic, and emotional burdens. Although preventative strategies do exist, the heterogeneity of allergy trajectories and clinical phenotypes has made it difficult to identify patients who would benefit from these strategies. Therefore, further studies investigating the molecular mechanisms that differentiate these trajectories are needed. Large-scale omics studies have identified key insights into the molecular mechanisms for many different diseases, however the application of these technologies to uncover the drivers of food allergy development is in its infancy. Here we review the use of omics approaches in food allergy and highlight key gaps in knowledge for applying these technologies for the characterization of food allergy development.

    View details for DOI 10.3389/falgy.2023.1149008

    View details for PubMedID 37034151

    View details for PubMedCentralID PMC10080041

  • Data-driven longitudinal characterization of neonatal health and morbidity. Science translational medicine De Francesco, D., Reiss, J. D., Roger, J., Tang, A. S., Chang, A. L., Becker, M., Phongpreecha, T., Espinosa, C., Morin, S., Berson, E., Thuraiappah, M., Le, B. L., Ravindra, N. G., Payrovnaziri, S. N., Mataraso, S., Kim, Y., Xue, L., Rosenstein, M. G., Oskotsky, T., Marić, I., Gaudilliere, B., Carvalho, B., Bateman, B. T., Angst, M. S., Prince, L. S., Blumenfeld, Y. J., Benitz, W. E., Fuerch, J. H., Shaw, G. M., Sylvester, K. G., Stevenson, D. K., Sirota, M., Aghaeepour, N. 2023; 15 (683): eadc9854


    Although prematurity is the single largest cause of death in children under 5 years of age, the current definition of prematurity, based on gestational age, lacks the precision needed for guiding care decisions. Here, we propose a longitudinal risk assessment for adverse neonatal outcomes in newborns based on a deep learning model that uses electronic health records (EHRs) to predict a wide range of outcomes over a period starting shortly before conception and ending months after birth. By linking the EHRs of the Lucile Packard Children's Hospital and the Stanford Healthcare Adult Hospital, we developed a cohort of 22,104 mother-newborn dyads delivered between 2014 and 2018. Maternal and newborn EHRs were extracted and used to train a multi-input multitask deep learning model, featuring a long short-term memory neural network, to predict 24 different neonatal outcomes. An additional cohort of 10,250 mother-newborn dyads delivered at the same Stanford Hospitals from 2019 to September 2020 was used to validate the model. Areas under the receiver operating characteristic curve at delivery exceeded 0.9 for 10 of the 24 neonatal outcomes considered and were between 0.8 and 0.9 for 7 additional outcomes. Moreover, comprehensive association analysis identified multiple known associations between various maternal and neonatal features and specific neonatal outcomes. This study used linked EHRs from more than 30,000 mother-newborn dyads and would serve as a resource for the investigation and prediction of neonatal outcomes. An interactive website is available for independent investigators to leverage this unique dataset:

    View details for DOI 10.1126/scitranslmed.adc9854

    View details for PubMedID 36791208

  • In-Silico Generation of High-Dimensional Immune Response Data in Patients using a Deep Neural Network. Cytometry. Part A : the journal of the International Society for Analytical Cytology Fallahzadeh, R., Bidoki, N. H., Stelzer, I. A., Becker, M., Marić, I., Chang, A. L., Culos, A., Phongpreecha, T., Xenochristou, M., De Francesco, D., Espinosa, C., Berson, E., Verdonk, F., Angst, M. S., Gaudilliere, B., Aghaeepour, N. 2022


    Technologies for single-cell profiling of the immune system have enabled researchers to extract rich interconnected networks of cellular abundance, phenotypical and functional cellular parameters. These studies can power machine learning approaches to understand the role of the immune system in various diseases. However, the performance of these approaches and the generalizability of the findings have been hindered by limited cohort sizes in translational studies, partially due to logistical demands and costs associated with longitudinal data collection in sufficiently large patient cohorts. An evolving challenge is the requirement for ever-increasing cohort sizes as the dimensionality of datasets grows. We propose a deep learning model derived from a novel pipeline of optimal temporal cell matching and overcomplete autoencoders that uses data from a small subset of patients to learn to forecast an entire patient's immune response in a high dimensional space from one timepoint to another. In our analysis of 1.08 million cells from patients pre- and post-surgical intervention, we demonstrate that the generated patient-specific data are qualitatively and quantitatively similar to real patient data by demonstrating fidelity, diversity, and usefulness. This article is protected by copyright. All rights reserved.

    View details for DOI 10.1002/cyto.a.24709

    View details for PubMedID 36507780

  • Early prediction and longitudinal modeling of preeclampsia from multiomics. Patterns (New York, N.Y.) Maric, I., Contrepois, K., Moufarrej, M. N., Stelzer, I. A., Feyaerts, D., Han, X., Tang, A., Stanley, N., Wong, R. J., Traber, G. M., Ellenberger, M., Chang, A. L., Fallahzadeh, R., Nassar, H., Becker, M., Xenochristou, M., Espinosa, C., De Francesco, D., Ghaemi, M. S., Costello, E. K., Culos, A., Ling, X. B., Sylvester, K. G., Darmstadt, G. L., Winn, V. D., Shaw, G. M., Relman, D. A., Quake, S. R., Angst, M. S., Snyder, M. P., Stevenson, D. K., Gaudilliere, B., Aghaeepour, N. 2022; 3 (12): 100655


    Preeclampsia is a complex disease of pregnancy whose physiopathology remains unclear. We developed machine-learning models for early prediction of preeclampsia (first 16weeks of pregnancy) and over gestation by analyzing six omics datasets from a longitudinal cohort of pregnant women. For early pregnancy, a prediction model using nine urine metabolites had the highest accuracy and was validated on an independent cohort (area under the receiver-operating characteristic curve [AUC]= 0.88, 95% confidence interval [CI] [0.76, 0.99] cross-validated; AUC= 0.83, 95% CI [0.62,1] validated). Univariate analysis demonstrated statistical significance of identified metabolites. An integrated multiomics model further improved accuracy (AUC= 0.94). Several biological pathways were identified including tryptophan, caffeine, and arachidonic acid metabolisms. Integration with immune cytometry data suggested novel associations between immune and proteomic dynamics. While further validation in a larger population is necessary, these encouraging results can serve as a basis for a simple, early diagnostic test for preeclampsia.

    View details for DOI 10.1016/j.patter.2022.100655

    View details for PubMedID 36569558

  • Integrated plasma proteomic and single-cell immune signaling network signatures demarcate mild, moderate, and severe COVID-19. Cell reports. Medicine Feyaerts, D., Hédou, J., Gillard, J., Chen, H., Tsai, E. S., Peterson, L. S., Ando, K., Manohar, M., Do, E., Dhondalay, G. K., Fitzpatrick, J., Artandi, M., Chang, I., Snow, T. T., Chinthrajah, R. S., Warren, C. M., Wittman, R., Meyerowitz, J. G., Ganio, E. A., Stelzer, I. A., Han, X., Verdonk, F., Gaudillière, D. K., Mukherjee, N., Tsai, A. S., Rumer, K. K., Jacobsen, D. R., Bjornson-Hooper, Z. B., Jiang, S., Saavedra, S. F., Valdés Ferrer, S. I., Kelly, J. D., Furman, D., Aghaeepour, N., Angst, M. S., Boyd, S. D., Pinsky, B. A., Nolan, G. P., Nadeau, K. C., Gaudillière, B., McIlwain, D. R. 2022: 100680


    The biological determinants underlying the range of coronavirus 2019 (COVID-19) clinical manifestations are not fully understood. Here, over 1,400 plasma proteins and 2,600 single-cell immune features comprising cell phenotype, endogenous signaling activity, and signaling responses to inflammatory ligands are cross-sectionally assessed in peripheral blood from 97 patients with mild, moderate, and severe COVID-19 and 40 uninfected patients. Using an integrated computational approach to analyze the combined plasma and single-cell proteomic data, we identify and independently validate a multi-variate model classifying COVID-19 severity (multi-class area under the curve [AUC]training = 0.799, p = 4.2e-6; multi-class AUCvalidation = 0.773, p = 7.7e-6). Examination of informative model features reveals biological signatures of COVID-19 severity, including the dysregulation of JAK/STAT, MAPK/mTOR, and nuclear factor κB (NF-κB) immune signaling networks in addition to recapitulating known hallmarks of COVID-19. These results provide a set of early determinants of COVID-19 severity that may point to therapeutic targets for prevention and/or treatment of COVID-19 progression.

    View details for DOI 10.1016/j.xcrm.2022.100680

    View details for PubMedID 35839768

  • Signature for Pain Recovery IN Teens (SPRINT): protocol for a multisite prospective signature study in chronic musculoskeletal pain. BMJ open Simons, L., Moayedi, M., Coghill, R. C., Stinson, J., Angst, M. S., Aghaeepour, N., Gaudilliere, B., King, C. D., López-Solà, M., Hoeppli, M. E., Biggs, E., Ganio, E., Williams, S. E., Goldschneider, K. R., Campbell, F., Ruskin, D., Krane, E. J., Walker, S., Rush, G., Heirich, M. 2022; 12 (6): e061548


    Current treatments for chronic musculoskeletal (MSK) pain are suboptimal. Discovery of robust prognostic markers separating patients who recover from patients with persistent pain and disability is critical for developing patient-specific treatment strategies and conceiving novel approaches that benefit all patients. Given that chronic pain is a biopsychosocial process, this study aims to discover and validate a robust prognostic signature that measures across multiple dimensions in the same adolescent patient cohort with a computational analysis pipeline. This will facilitate risk stratification in adolescent patients with chronic MSK pain and more resourceful allocation of patients to costly and potentially burdensome multidisciplinary pain treatment approaches.Here we describe a multi-institutional effort to collect, curate and analyse a high dimensional data set including epidemiological, psychometric, quantitative sensory, brain imaging and biological information collected over the course of 12 months. The aim of this effort is to derive a multivariate model with strong prognostic power regarding the clinical course of adolescent MSK pain and function.The study complies with the National Institutes of Health policy on the use of a single internal review board (sIRB) for multisite research, with Cincinnati Children's Hospital Medical Center Review Board as the reviewing IRB. Stanford's IRB is a relying IRB within the sIRB. As foreign institutions, the University of Toronto and The Hospital for Sick Children (SickKids) are overseen by their respective ethics boards. All participants provide signed informed consent. We are committed to open-access publication, so that patients, clinicians and scientists have access to the study data and the signature(s) derived. After findings are published, we will upload a limited data set for sharing with other investigators on applicable repositories.NCT04285112.

    View details for DOI 10.1136/bmjopen-2022-061548

    View details for PubMedID 35676017

  • A data-driven health index for neonatal morbidities. iScience De Francesco, D., Blumenfeld, Y. J., Maric, I., Mayo, J. A., Chang, A. L., Fallahzadeh, R., Phongpreecha, T., Butwick, A. J., Xenochristou, M., Phibbs, C. S., Bidoki, N. H., Becker, M., Culos, A., Espinosa, C., Liu, Q., Sylvester, K. G., Gaudilliere, B., Angst, M. S., Stevenson, D. K., Shaw, G. M., Aghaeepour, N. 2022; 25 (4): 104143


    Whereas prematurity is a major cause of neonatal mortality, morbidity, and lifelong impairment, the degree of prematurity is usually defined by the gestational age (GA) at delivery rather than by neonatal morbidity. Here we propose a multi-task deep neural network model that simultaneously predicts twelve neonatal morbidities, as the basis for a new data-driven approach to define prematurity. Maternal demographics, medical history, obstetrical complications, and prenatal fetal findings were obtained from linked birth certificates and maternal/infant hospitalization records for 11,594,786 livebirths in California from 1991 to 2012. Overall, our model outperformed traditional models to assess prematurity which are based on GA and/or birthweight (area under the precision-recall curve was 0.326 for our model, 0.229 for GA, and 0.156 for small for GA). These findings highlight the potential of using machine learning techniques to predict multiple prematurity phenotypes and inform clinical decisions to prevent, diagnose and treat neonatal morbidities.

    View details for DOI 10.1016/j.isci.2022.104143

    View details for PubMedID 35402862

  • MULTIOMICS LONGITUDINAL MODELING OF PREECLAMPTIC PREGNANCIES Espinosa, C., Maric, I., Contrepois, K., Moufarrej, M., Stelzer, I. S., Feyaerts, D., Han, X., Tang, A., Wong, R. J., Darmstadt, G. L., Winn, V. D., Shaw, G. M., Relman, D. A., Quake, S. R., Angst, M. S., Snyder, M., Stevenson, D. K., Gaudilliere, B., Aghaeepour, N. BMJ PUBLISHING GROUP. 2022: 309
  • Revealing the impact of lifestyle stressors on the risk of adverse pregnancy outcomes with multitask machine learning. Frontiers in pediatrics Becker, M., Dai, J., Chang, A. L., Feyaerts, D., Stelzer, I. A., Zhang, M., Berson, E., Saarunya, G., De Francesco, D., Espinosa, C., Kim, Y., Maric, I., Mataraso, S., Payrovnaziri, S. N., Phongpreecha, T., Ravindra, N. G., Shome, S., Tan, Y., Thuraiappah, M., Xue, L., Mayo, J. A., Quaintance, C. C., Laborde, A., King, L. S., Dhabhar, F. S., Gotlib, I. H., Wong, R. J., Angst, M. S., Shaw, G. M., Stevenson, D. K., Gaudilliere, B., Aghaeepour, N. 2022; 10: 933266


    Psychosocial and stress-related factors (PSFs), defined as internal or external stimuli that induce biological changes, are potentially modifiable factors and accessible targets for interventions that are associated with adverse pregnancy outcomes (APOs). Although individual APOs have been shown to be connected to PSFs, they are biologically interconnected, relatively infrequent, and therefore challenging to model. In this context, multi-task machine learning (MML) is an ideal tool for exploring the interconnectedness of APOs on the one hand and building on joint combinatorial outcomes to increase predictive power on the other hand. Additionally, by integrating single cell immunological profiling of underlying biological processes, the effects of stress-based therapeutics may be measurable, facilitating the development of precision medicine approaches.Objectives: The primary objectives were to jointly model multiple APOs and their connection to stress early in pregnancy, and to explore the underlying biology to guide development of accessible and measurable interventions.Materials and Methods: In a prospective cohort study, PSFs were assessed during the first trimester with an extensive self-filled questionnaire for 200 women. We used MML to simultaneously model, and predict APOs (severe preeclampsia, superimposed preeclampsia, gestational diabetes and early gestational age) as well as several risk factors (BMI, diabetes, hypertension) for these patients based on PSFs. Strongly interrelated stressors were categorized to identify potential therapeutic targets. Furthermore, for a subset of 14 women, we modeled the connection of PSFs to the maternal immune system to APOs by building corresponding ML models based on an extensive single cell immune dataset generated by mass cytometry time of flight (CyTOF).Results: Jointly modeling APOs in a MML setting significantly increased modeling capabilities and yielded a highly predictive integrated model of APOs underscoring their interconnectedness. Most APOs were associated with mental health, life stress, and perceived health risks. Biologically, stressors were associated with specific immune characteristics revolving around CD4/CD8 T cells. Immune characteristics predicted based on stress were in turn found to be associated with APOs.Conclusions: Elucidating connections among stress, multiple APOs simultaneously, and immune characteristics has the potential to facilitate the implementation of ML-based, individualized, integrative models of pregnancy in clinical decision making. The modifiable nature of stressors may enable the development of accessible interventions, with success tracked through immune characteristics.

    View details for DOI 10.3389/fped.2022.933266

    View details for PubMedID 36582513

  • Maternal stress and its consequences - biological strain. American journal of perinatology Stevenson, D. K., Gotlib, I. H., Buthmann, J. L., Maric, I., Aghaeepour, N., Gaudilliere, B., Angst, M. S., Darmstadt, G. L., Druzin, M. L., Wong, R. J., Shaw, G. M., Katz, M. 2022


    Understanding the role of stress in pregnancy and its consequences is important, particularly given documented associations between maternal stress and preterm birth and other pathologic outcomes. Physical and psychological stressors can elicit the same biological responses, known as biological strain. Chronic stressors, like poverty and racism (race-based discriminatory treatment), may create a legacy or trajectory of biological strain that no amount of coping can relieve in the absence of larger-scale socio-behavioral or societal changes. An integrative approach that takes into consideration simultaneously social and biological determinants of stress may provide the best insights into risk for preterm birth. The most successful computational approaches and the most predictive machine-learning models are likely to be those that combine information about the stressors and the biological strain (for example, as measured by different omics) experienced during pregnancy.

    View details for DOI 10.1055/a-1798-1602

    View details for PubMedID 35292943

  • Integrated Single-Cell and Plasma Proteomic Modeling to Predict Surgical Site Complications: A Prospective Cohort Study. Annals of surgery Rumer, K. K., Hedou, J., Tsai, A., Einhaus, J., Verdonk, F., Stanley, N., Choisy, B., Ganio, E., Bonham, A., Jacobsen, D., Warrington, B., Gao, X., Tingle, M., McAllister, T. N., Fallahzadeh, R., Feyaerts, D., Stelzer, I., Gaudilliere, D., Ando, K., Shelton, A., Morris, A., Kebebew, E., Aghaeepour, N., Kin, C., Angst, M. S., Gaudilliere, B. 1800


    OBJECTIVE: The aim of this study was to determine whether single-cell and plasma proteomic elements of the host's immune response to surgery accurately identify patients who develop a surgical site complication (SSC) after major abdominal surgery.SUMMARY BACKGROUND DATA: SSCs may occur in up to 25% of patients undergoing bowel resection, resulting in significant morbidity and economic burden. However, the accurate prediction of SSCs remains clinically challenging. Leveraging high-content proteomic technologies to comprehensively profile patients' immune response to surgery is a promising approach to identify predictive biological factors of SSCs.METHODS: Forty-one patients undergoing non-cancer bowel resection were prospectively enrolled. Blood samples collected before surgery and on postoperative day one (POD1) were analyzed using a combination of single-cell mass cytometry and plasma proteomics. The primary outcome was the occurrence of an SSC, including surgical site infection, anastomotic leak, or wound dehiscence within 30 days of surgery.RESULTS: A multiomic model integrating the single-cell and plasma proteomic data collected on POD1 accurately differentiated patients with (n = 11) and without (n = 30) an SSC [area under the curve (AUC) = 0.86]. Model features included coregulated proinflammatory (eg, IL-6- and MyD88- signaling responses in myeloid cells) and immunosuppressive (eg, JAK/STAT signaling responses in M-MDSCs and Tregs) events preceding an SSC. Importantly, analysis of the immunological data obtained before surgery also yielded a model accurately predicting SSCs (AUC = 0.82).CONCLUSIONS: The multiomic analysis of patients' immune response after surgery and immune state before surgery revealed systemic immune signatures preceding the development of SSCs. Our results suggest that integrating immunological data in perioperative risk assessment paradigms is a plausible strategy to guide individualized clinical care.

    View details for DOI 10.1097/SLA.0000000000005348

    View details for PubMedID 34954754

  • Preoperative Opioid Utilization Patterns and Postoperative Opioid Utilization: A Retrospective Cohort Study. Anesthesiology Rishel, C. A., Angst, M. S., Sun, E. C. 2021; 135 (6): 1015-1026


    BACKGROUND: Among chronic opioid users, the association between decreasing or increasing preoperative opioid utilization and postoperative outcomes is unknown. The authors hypothesized that decreasing utilization would be associated with improved outcomes and increasing utilization with worsened outcomes.METHODS: Using commercial insurance claims, the authors identified 57,019 chronic opioid users (10 or more prescriptions or 120 or more days supplied during the preoperative year), age 18 to 89 yr, undergoing one of 10 surgeries between 2004 and 2018. Patients with a 20% or greater decrease or increase in opioid utilization between preoperative days 7 to 90 and 91 to 365 were compared to patients with less than 20% change (stable utilization). The primary outcome was opioid utilization during postoperative days 91 to 365. Secondary outcomes included alternative measures of postoperative opioid utilization (filling a minimum number of prescriptions during this period), postoperative adverse events, and healthcare utilization.RESULTS: The average age was 63 ± 13 yr, with 38,045 (66.7%) female patients. Preoperative opioid utilization was decreasing for 12,347 (21.7%) patients, increasing for 21,330 (37.4%) patients, and stable for 23,342 (40.9%) patients. Patients with decreasing utilization were slightly less likely to fill an opioid prescription during postoperative days 91 to 365 compared to stable patients (89.2% vs. 96.4%; odds ratio, 0.323; 95% CI, 0.296 to 0.352; P < 0.001), though the average daily doses were similar among patients who continued to utilize opioids during this timeframe (46.7 vs. 46.5 morphine milligram equivalents; difference, 0.2; 95% CI, -0.8 to 1.2; P = 0.684). Of patients with increasing utilization, 93.6% filled opioid prescriptions during this period (odds ratio, 0.57; 95% CI, 0.52 to 0.62; P < 0.001), with slightly lower average daily doses (44.3 morphine milligram equivalents; difference, -2.2; 95% CI, -3.1 to -1.3; P < 0.001). Except for alternative measures of persistent postoperative opioid utilization, there were no clinically significant differences for the secondary outcomes.CONCLUSIONS: Changes in preoperative opioid utilization were not associated with clinically significant differences for several postoperative outcomes including postoperative opioid utilization.EDITORS PERSPECTIVE:

    View details for DOI 10.1097/ALN.0000000000004026

    View details for PubMedID 34731242

  • Plasma Biomarkers of Tau and Neurodegeneration During Major Cardiac and Noncardiac Surgery. JAMA neurology Feinstein, I., Wilson, E. N., Swarovski, M. S., Andreasson, K. I., Angst, M. S., Greicius, M. D. 2021

    View details for DOI 10.1001/jamaneurol.2021.2823

    View details for PubMedID 34542578

  • Integrated trajectories of the maternal metabolome, proteome, and immunome predict labor onset. Science translational medicine Stelzer, I. A., Ghaemi, M. S., Han, X., Ando, K., Hedou, J. J., Feyaerts, D., Peterson, L. S., Rumer, K. K., Tsai, E. S., Ganio, E. A., Gaudilliere, D. K., Tsai, A. S., Choisy, B., Gaigne, L. P., Verdonk, F., Jacobsen, D., Gavasso, S., Traber, G. M., Ellenberger, M., Stanley, N., Becker, M., Culos, A., Fallahzadeh, R., Wong, R. J., Darmstadt, G. L., Druzin, M. L., Winn, V. D., Gibbs, R. S., Ling, X. B., Sylvester, K., Carvalho, B., Snyder, M. P., Shaw, G. M., Stevenson, D. K., Contrepois, K., Angst, M. S., Aghaeepour, N., Gaudilliere, B. 2021; 13 (592)


    Estimating the time of delivery is of high clinical importance because pre- and postterm deviations are associated with complications for the mother and her offspring. However, current estimations are inaccurate. As pregnancy progresses toward labor, major transitions occur in fetomaternal immune, metabolic, and endocrine systems that culminate in birth. The comprehensive characterization of maternal biology that precedes labor is key to understanding these physiological transitions and identifying predictive biomarkers of delivery. Here, a longitudinal study was conducted in 63 women who went into labor spontaneously. More than 7000 plasma analytes and peripheral immune cell responses were analyzed using untargeted mass spectrometry, aptamer-based proteomic technology, and single-cell mass cytometry in serial blood samples collected during the last 100 days of pregnancy. The high-dimensional dataset was integrated into a multiomic model that predicted the time to spontaneous labor [R = 0.85, 95% confidence interval (CI) [0.79 to 0.89], P = 1.2 * 10-40, N = 53, training set; R = 0.81, 95% CI [0.61 to 0.91], P = 3.9 * 10-7, N = 10, independent test set]. Coordinated alterations in maternal metabolome, proteome, and immunome marked a molecular shift from pregnancy maintenance to prelabor biology 2 to 4 weeks before delivery. A surge in steroid hormone metabolites and interleukin-1 receptor type 4 that preceded labor coincided with a switch from immune activation to regulation of inflammatory responses. Our study lays the groundwork for developing blood-based methods for predicting the day of labor, anchored in mechanisms shared in preterm and term pregnancies.

    View details for DOI 10.1126/scitranslmed.abd9898

    View details for PubMedID 33952678

  • Stimulant use for self-management of pain among safety-net patients with chronic non-cancer pain. Substance abuse Beliveau, C. M., McMahan, V. M., Arenander, J., Angst, M. S., Kushel, M., Torres, A., Santos, G., Coffin, P. O. 2021: 1–8


    BACKGROUND: Chronic pain affects one-fifth of US adults. Reductions in opioid prescribing have been associated with increased non-prescription opioid use and, chronologically, increased stimulant (methamphetamine and cocaine) use. While non-prescription opioid use is commonly attributed to pain self-management, the role of stimulants in managing pain is unclear.METHODS: We analyzed baseline data from a longitudinal study of patients with chronic non-cancer pain in an urban safety-net healthcare system who had been prescribed an opioid for ≥3 of the last 12months, and had a history of non-prescription opioid, cocaine, or amphetamine use (N=300). We estimated the prevalence and identified correlates of stimulant use to treat pain among a subgroup of patients who reported past-year stimulant use (N=105). Data sources included computer-assisted questionnaire (demographics, substance use, pain), clinical exam and procedures (pain, pain tolerance), and chart abstraction (opioid prescriptions). We conducted bivariate analyses to assess associations between demographics, pain characteristics, non-opioid therapies, substance use, opioid prescriptions, and self-reported symptoms, with reporting using stimulants to treat pain. Demographic variables and those with significant bivariate associations were included in a multivariable logistic regression model.RESULTS: Fifty-two percent of participants with past-year stimulant use reported using stimulants in the past year to treat pain. Participants who used stimulants for pain reported slightly higher average pain in the past 3months (median of 8 (IQR: 6-8) vs 7 (7-9) out of 10, p=0.049). In the multivariable analysis, female gender (AOR= 3.20, 95% CI: 1.06-9.63, p=0.039) and higher score on the Douleur Neuropathique 4 neuropathic pain questionnaire (AOR = 1.34, 95% CI: 1.05-1.70, p=0.017) were associated with past-year stimulant use to treat pain.CONCLUSION: Stimulants may be used for pain self-management, particularly for neuropathic pain and among women. Our findings suggest an underexplored motivation for stimulant use in an era of reduced access to prescribed opioids.

    View details for DOI 10.1080/08897077.2021.1903654

    View details for PubMedID 33798030

  • Understanding how biologic and social determinants affect disparities in preterm birth and outcomes of preterm infants in the NICU. Seminars in perinatology Stevenson, D. K., Aghaeepour, N., Maric, I., Angst, M. S., Darmstadt, G. L., Druzin, M. L., Gaudilliere, B., Ling, X. B., Moufarrej, M. N., Peterson, L. S., Quake, S. R., Relman, D. A., Snyder, M. P., Sylvester, K. G., Shaw, G. M., Wong, R. J. 2021: 151408


    To understand the disparities in spontaneous preterm birth (sPTB) and/or its outcomes, biologic and social determinants as well as healthcare practice (such as those in neonatal intensive care units) should be considered. They have been largely intractable and remain obscure in most cases, despite a myriad of identified risk factors for and causes of sPTB. We still do not know how they might actually affect and lead to the different outcomes at different gestational ages and if they are independent of NICU practices. Here we describe an integrated approach to study the interplay between the genome and exposome, which may drive biochemistry and physiology, with health disparities.

    View details for DOI 10.1016/j.semperi.2021.151408

    View details for PubMedID 33875265

  • Integrated plasma proteomic and single-cell immune signaling network signatures demarcate mild, moderate, and severe COVID-19. bioRxiv : the preprint server for biology Feyaerts, D., Hédou, J., Gillard, J., Chen, H., Tsai, E. S., Peterson, L. S., Ando, K., Manohar, M., Do, E., Dhondalay, G. K., Fitzpatrick, J., Artandi, M., Chang, I., Snow, T. T., Chinthrajah, R. S., Warren, C. M., Wittman, R., Meyerowitz, J. G., Ganio, E. A., Stelzer, I. A., Han, X., Verdonk, F., Gaudillière, D. K., Mukherjee, N., Tsai, A. S., Rumer, K. K., Jiang, S., Valdés Ferrer, S. I., Kelly, J. D., Furman, D., Aghaeepour, N., Angst, M. S., Boyd, S. D., Pinsky, B. A., Nolan, G. P., Nadeau, K. C., Gaudillière, B., McIlwain, D. R. 2021


    The biological determinants of the wide spectrum of COVID-19 clinical manifestations are not fully understood. Here, over 1400 plasma proteins and 2600 single-cell immune features comprising cell phenotype, basal signaling activity, and signaling responses to inflammatory ligands were assessed in peripheral blood from patients with mild, moderate, and severe COVID-19, at the time of diagnosis. Using an integrated computational approach to analyze the combined plasma and single-cell proteomic data, we identified and independently validated a multivariate model classifying COVID-19 severity (multi-class AUCtraining = 0.799, p-value = 4.2e-6; multi-class AUCvalidation = 0.773, p-value = 7.7e-6). Features of this high-dimensional model recapitulated recent COVID-19 related observations of immune perturbations, and revealed novel biological signatures of severity, including the mobilization of elements of the renin-angiotensin system and primary hemostasis, as well as dysregulation of JAK/STAT, MAPK/mTOR, and NF-κB immune signaling networks. These results provide a set of early determinants of COVID-19 severity that may point to therapeutic targets for the prevention of COVID-19 progression.

    View details for DOI 10.1101/2021.02.09.430269

    View details for PubMedID 33594362

    View details for PubMedCentralID PMC7885914

  • Single-Cell Analysis of the Neonatal Immune System Across the Gestational Age Continuum. Frontiers in immunology Peterson, L. S., Hedou, J., Ganio, E. A., Stelzer, I. A., Feyaerts, D., Harbert, E., Adusumelli, Y., Ando, K., Tsai, E. S., Tsai, A. S., Han, X., Ringle, M., Houghteling, P., Reiss, J. D., Lewis, D. B., Winn, V. D., Angst, M. S., Aghaeepour, N., Stevenson, D. K., Gaudilliere, B. 2021; 12: 714090


    Although most causes of death and morbidity in premature infants are related to immune maladaptation, the premature immune system remains poorly understood. We provide a comprehensive single-cell depiction of the neonatal immune system at birth across the spectrum of viable gestational age (GA), ranging from 25 weeks to term. A mass cytometry immunoassay interrogated all major immune cell subsets, including signaling activity and responsiveness to stimulation. An elastic net model described the relationship between GA and immunome (R=0.85, p=8.75e-14), and unsupervised clustering highlighted previously unrecognized GA-dependent immune dynamics, including decreasing basal MAP-kinase/NFκB signaling in antigen presenting cells; increasing responsiveness of cytotoxic lymphocytes to interferon-α; and decreasing frequency of regulatory and invariant T cells, including NKT-like cells and CD8+CD161+ T cells. Knowledge gained from the analysis of the neonatal immune landscape across GA provides a mechanistic framework to understand the unique susceptibility of preterm infants to both hyper-inflammatory diseases and infections.

    View details for DOI 10.3389/fimmu.2021.714090

    View details for PubMedID 34497610

    View details for PubMedCentralID PMC8420969

  • Deleterious and Protective Psychosocial and Stress-Related Factors Predict Risk of Spontaneous Preterm Birth. American journal of perinatology Becker, M. n., Mayo, J. A., Phogat, N. K., Quaintance, C. C., Laborde, A. n., King, L. n., Gotlib, I. H., Gaudilliere, B. n., Angst, M. S., Shaw, G. M., Stevenson, D. K., Aghaeepour, N. n., Dhabhar, F. S. 2021


     The aim of the study was to: (1) Identify (early in pregnancy) psychosocial and stress-related factors that predict risk of spontaneous preterm birth (PTB, gestational age <37 weeks); (2) Investigate whether "protective" factors (e.g., happiness/social support) decrease risk; (3) Use the Dhabhar Quick-Assessment Questionnaire for Stress and Psychosocial Factors™ (DQAQ-SPF™) to rapidly quantify harmful or protective factors that predict increased or decreased risk respectively, of PTB. This is a prospective cohort study. Relative risk (RR) analyses investigated association between individual factors and PTB. Machine learning-based interdependency analysis (IDPA) identified factor clusters, strength, and direction of association with PTB. A nonlinear model based on support vector machines was built for predicting PTB and identifying factors that most strongly predicted PTB. Higher levels of deleterious factors were associated with increased RR for PTB: General anxiety (RR = 8.9; 95% confidence interval or CI = 2.0,39.6), pain (RR = 5.7; CI = 1.7,17.0); tiredness/fatigue (RR = 3.7; CI = 1.09,13.5); perceived risk of birth complications (RR = 4; CI = 1.6,10.01); self-rated health current (RR = 2.6; CI = 1.0,6.7) and previous 3 years (RR = 2.9; CI = 1.1,7.7); and divorce (RR = 2.9; CI = 1.1,7.8). Lower levels of protective factors were also associated with increased RR for PTB: low happiness (RR = 9.1; CI = 1.25,71.5); low support from parents/siblings (RR = 3.5; CI = 0.9,12.9), and father-of-baby (RR = 3; CI = 1.1,9.9). These factors were also components of the clusters identified by the IDPA: perceived risk of birth complications (p < 0.05 after FDR correction), and general anxiety, happiness, tiredness/fatigue, self-rated health, social support, pain, and sleep (p < 0.05 without FDR correction). Supervised analysis of all factors, subject to cross-validation, produced a model highly predictive of PTB (AUROC or area under the receiver operating characteristic = 0.73). Model reduction through forward selection revealed that even a small set of factors (including those identified by RR and IDPA) predicted PTB. These findings represent an important step toward identifying key factors, which can be assessed rapidly before/after conception, to predict risk of PTB, and perhaps other adverse pregnancy outcomes. Quantifying these factors, before, or early in pregnancy, could identify women at risk of delivering preterm, pinpoint mechanisms/targets for intervention, and facilitate the development of interventions to prevent PTB.· Newly designed questionnaire used for rapid quantification of stress and psychosocial factors early during pregnancy.. · Deleterious factors predict increased preterm birth (PTB) risk.. · Protective factors predict decreased PTB risk..

    View details for DOI 10.1055/s-0041-1729162

    View details for PubMedID 34015838

  • Human immune system adaptations to simulated microgravity revealed by single-cell mass cytometry. Scientific reports Spatz, J. M., Fulford, M. H., Tsai, A., Gaudilliere, D., Hedou, J., Ganio, E., Angst, M., Aghaeepour, N., Gaudilliere, B. 2021; 11 (1): 11872


    Exposure to microgravity (µG) during space flights produces a state of immunosuppression, leading to increased viral shedding, which could interfere with long term missions. However, the cellular mechanisms that underlie the immunosuppressive effects of µG are ill-defined. A deep understanding of human immune adaptations to µG is a necessary first step to design data-driven interventions aimed at preserving astronauts' immune defense during short- and long-term spaceflights. We employed a high-dimensional mass cytometry approach to characterize over 250 cell-specific functional responses in 18 innate and adaptive immune cell subsets exposed to 1G or simulated (s)µG using the Rotating Wall Vessel. A statistically stringent elastic net method produced a multivariate model that accurately stratified immune responses observed in 1G and sµG (p value 2E-4, cross-validation). Aspects of our analysis resonated with prior knowledge of human immune adaptations to µG, including the dampening of Natural Killer, CD4+ and CD8+ T cell responses. Remarkably, we found that sµG enhanced STAT5 signaling responses of immunosuppressive Tregs. Our results suggest µG exerts a dual effect on the human immune system, simultaneously dampening cytotoxic responses while enhancing Treg function. Our study provides a single-cell readout of sµG-induced immune dysfunctions and an analytical framework for future studies of human immune adaptations to human long-term spaceflights.

    View details for DOI 10.1038/s41598-021-90458-2

    View details for PubMedID 34099760

  • Objective Activity Parameters Track Patient-Specific Physical Recovery Trajectories After Surgery and Link With Individual Preoperative Immune States. Annals of surgery Fallahzadeh, R., Verdonk, F., Ganio, E., Culos, A., Stanley, N., Marić, I., Chang, A. L., Becker, M., Phongpreecha, T., Xenochristou, M., De Francesco, D., Espinosa, C., Gao, X., Tsai, A., Sultan, P., Tingle, M., Amanatullah, D. F., Huddleston, J. I., Goodman, S. B., Gaudilliere, B., Angst, M. S., Aghaeepour, N. 2021


    The longitudinal assessment of physical function with high temporal resolution at a scalable and objective level in patients recovering from surgery is highly desirable to understand the biological and clinical factors that drive the clinical outcome. However, physical recovery from surgery itself remains poorly defined and the utility of wearable technologies to study recovery after surgery has not been established.Prolonged postoperative recovery is often associated with long-lasting impairment of physical, mental, and social functions. While phenotypical and clinical patient characteristics account for some variation of individual recovery trajectories, biological differences likely play a major role. Specifically, patient-specific immune states have been linked to prolonged physical impairment after surgery. However, current methods of quantifying physical recovery lack patient specificity and objectivity.Here, a combined high-fidelity accelerometry and state-of-the-art deep immune profiling approach was studied in patients undergoing major joint replacement surgery. The aim was to determine whether objective physical parameters derived from accelerometry data can accurately track patient-specific physical recovery profiles (suggestive of a 'clock of postoperative recovery'), compare the performance of derived parameters with benchmark metrics including step count, and link individual recovery profiles with patients' preoperative immune state.The results of our models indicate that patient-specific temporal patterns of physical function can be derived with a precision superior to benchmark metrics. Notably, six distinct domains of physical function and sleep are identified to represent the objective temporal patterns: "activity capacity" and "moderate and overall activity" (declined immediately after surgery); "sleep disruption and sedentary activity" (increased after surgery); "overall sleep", "sleep onset", and "light activity" (no clear changes were observed after surgery). These patterns can be linked to individual patients' preoperative immune state using cross-validated canonical-correlation analysis. Importantly, the pSTAT3 signal activity in M-MDSCs predicted a slower recovery.Accelerometry-based recovery trajectories are scalable and objective outcomes to study patient-specific factors that drive physical recovery.

    View details for DOI 10.1097/SLA.0000000000005250

    View details for PubMedID 35129529

  • A Peripheral Immune Signature of Labor Induction. Frontiers in immunology Ando, K., Hédou, J. J., Feyaerts, D., Han, X., Ganio, E. A., Tsai, E. S., Peterson, L. S., Verdonk, F., Tsai, A. S., Marić, I., Wong, R. J., Angst, M. S., Aghaeepour, N., Stevenson, D. K., Blumenfeld, Y. J., Sultan, P., Carvalho, B., Stelzer, I. A., Gaudillière, B. 2021; 12: 725989


    Approximately 1 in 4 pregnant women in the United States undergo labor induction. The onset and establishment of labor, particularly induced labor, is a complex and dynamic process influenced by multiple endocrine, inflammatory, and mechanical factors as well as obstetric and pharmacological interventions. The duration from labor induction to the onset of active labor remains unpredictable. Moreover, prolonged labor is associated with severe complications for the mother and her offspring, most importantly chorioamnionitis, uterine atony, and postpartum hemorrhage. While maternal immune system adaptations that are critical for the maintenance of a healthy pregnancy have been previously characterized, the role of the immune system during the establishment of labor is poorly understood. Understanding maternal immune adaptations during labor initiation can have important ramifications for predicting successful labor induction and labor complications in both induced and spontaneous types of labor. The aim of this study was to characterize labor-associated maternal immune system dynamics from labor induction to the start of active labor. Serial blood samples from fifteen participants were collected immediately prior to labor induction (baseline) and during the latent phase until the start of active labor. Using high-dimensional mass cytometry, a total of 1,059 single-cell immune features were extracted from each sample. A multivariate machine-learning method was employed to characterize the dynamic changes of the maternal immune system after labor induction until the establishment of active labor. A cross-validated linear sparse regression model (least absolute shrinkage and selection operator, LASSO) predicted the minutes since induction of labor with high accuracy (R = 0.86, p = 6.7e-15, RMSE = 277 min). Immune features most informative for the model included STAT5 signaling in central memory CD8+ T cells and pro-inflammatory STAT3 signaling responses across multiple adaptive and innate immune cell subsets. Our study reports a peripheral immune signature of labor induction, and provides important insights into biological mechanisms that may ultimately predict labor induction success as well as complications, thereby facilitating clinical decision-making to improve maternal and fetal well-being.

    View details for DOI 10.3389/fimmu.2021.725989

    View details for PubMedID 34566984

    View details for PubMedCentralID PMC8458888

  • Measuring the human immune response to surgery: multiomics for the prediction of postoperative outcomes. Current opinion in critical care Verdonk, F., Einhaus, J., Tsai, A. S., Hedou, J., Choisy, B., Gaudilliere, D., Kin, C., Aghaeepour, N., Angst, M. S., Gaudilliere, B. 2021


    Postoperative complications including infections, cognitive impairment, and protracted recovery occur in one-third of the 300 million surgeries performed annually worldwide. Complications cause personal suffering along with a significant economic burden on our healthcare system. However, the accurate prediction of postoperative complications and patient-targeted interventions for their prevention remain as major clinical challenges.Although multifactorial in origin, the dysregulation of immunological mechanisms that occur in response to surgical trauma is a key determinant of postoperative complications. Prior research, primarily focusing on inflammatory plasma markers, has provided important clues regarding their pathogenesis. However, the recent advent of high-content, single-cell transcriptomic, and proteomic technologies has considerably improved our ability to characterize the immune response to surgery, thereby providing new means to understand the immunological basis of postoperative complications and to identify prognostic biological signatures.The comprehensive and single-cell characterization of the human immune response to surgery has significantly advanced our ability to predict the risk of postoperative complications. Multiomic modeling of patients' immune states holds promise for the discovery of preoperative predictive biomarkers, ultimately providing patients and surgeons with actionable information to improve surgical outcomes. Although recent studies have generated a wealth of knowledge, laying the foundation for a single-cell atlas of the human immune response to surgery, larger-scale multiomic studies are required to derive robust, scalable, and sufficiently powerful models to accurately predict the risk of postoperative complications in individual patients.

    View details for DOI 10.1097/MCC.0000000000000883

    View details for PubMedID 34545029

  • Proposed domains for assessing postpartum recovery: A concept elicitation study. BJOG : an international journal of obstetrics and gynaecology Sultan, P., Jensen, S. E., Taylor, J., El-Sayed, Y., Carmichael, S., Cella, D., Angst, M. S., Gaudilliere, B., Lyell, D. J., Carvalho, B. 2021


    To propose postpartum recovery domains.Concept elicitation study SETTING: Semi-structured interviews POPULATION: 10 writing committee members and 50 stakeholder interviews (23 postpartum women, 9 general obstetricians, 5 maternal fetal medicine specialists, 8 nurses and 5 obstetric anaesthetists).Alternating interviews and focus group meetings until concept saturation was achieved (no new themes in 3 consecutive interviews). Interviews were digitally recorded and transcribed, and an iterative coding process utilised to identify domains.The primary outcome was to identify recovery domains. We also report key symptoms and concerns. Discussion frequency and importance scores (0-100; 0=not important; 100=vitally important to recovery) were used to rank domains. Discussion frequency was used to rank factors helping and hindering recovery, and determine the greatest challenges experienced postpartum.34 interviews and 2 focus group meetings were performed. The 13 postpartum recovery domains identified, (ranked highest to lowest) were: psychosocial distress, surgical / medical factors, infant feeding and breast health, psychosocial support, pain, physical function, sleep, motherhood experience, infant health, fatigue, appearance, sexual function and cognition. The most frequently discussed factors facilitating postpartum recovery were: family support, lactation / breastfeeding support and partner support. The most frequently discussed factor hindering recovery was inadequate social support. The most frequent challenges reported were: breastfeeding (week 1), breastfeeding (week 3) and sleep (week 6).We propose 13 domains, which comprehensively describe recovery in women delivering in a single centre within the United States. This provides a novel framework to study the postpartum recovery process.

    View details for DOI 10.1111/1471-0528.16937

    View details for PubMedID 34536324

  • Patient phenotyping in clinical trials of chronic pain treatments: IMMPACT recommendations PAIN REPORTS Edwards, R. R., Dworkin, R. H., Turk, D. C., Angst, M. S., Dionne, R., Freeman, R., Hansson, P., Haroutounian, S., Arendt-Nielsen, L., Attal, N., Baron, R., Brell, J., Bujanover, S., Burke, L. B., Carr, D., Chappell, A. S., Cowan, P., Etropolski, M., Fillingim, R. B., Gewandter, J. S., Katz, N. P., Kopecky, E. A., Markman, J. D., Nomikos, G., Porter, L., Rappaport, B. A., Rice, A. C., Scavone, J. M., Scholz, J., Simon, L. S., Smith, S. M., Tobias, J., Tockarshewsky, T., Veasley, C., Versavel, M., Wasan, A. D., Wen, W., Yarnitsky, D. 2021; 6 (1)
  • Data-Driven Modeling of Pregnancy-Related Complications. Trends in molecular medicine Espinosa, C. n., Becker, M. n., Marić, I. n., Wong, R. J., Shaw, G. M., Gaudilliere, B. n., Aghaeepour, N. n., Stevenson, D. K. 2021


    A healthy pregnancy depends on complex interrelated biological adaptations involving placentation, maternal immune responses, and hormonal homeostasis. Recent advances in high-throughput technologies have provided access to multiomics biological data that, combined with clinical and social data, can provide a deeper understanding of normal and abnormal pregnancies. Integration of these heterogeneous datasets using state-of-the-art machine-learning methods can enable the prediction of short- and long-term health trajectories for a mother and offspring and the development of treatments to prevent or minimize complications. We review advanced machine-learning methods that could: provide deeper biological insights into a pregnancy not yet unveiled by current methodologies; clarify the etiologies and heterogeneity of pathologies that affect a pregnancy; and suggest the best approaches to address disparities in outcomes affecting vulnerable populations.

    View details for DOI 10.1016/j.molmed.2021.01.007

    View details for PubMedID 33573911

  • Proteomic signatures predict preeclampsia in individual cohorts but not across cohorts - implications for clinical biomarker studies. The journal of maternal-fetal & neonatal medicine : the official journal of the European Association of Perinatal Medicine, the Federation of Asia and Oceania Perinatal Societies, the International Society of Perinatal Obstetricians Ghaemi, M. S., Tarca, A. L., Romero, R. n., Stanley, N. n., Fallahzadeh, R. n., Tanada, A. n., Culos, A. n., Ando, K. n., Han, X. n., Blumenfeld, Y. J., Druzin, M. L., El-Sayed, Y. Y., Gibbs, R. S., Winn, V. D., Contrepois, K. n., Ling, X. B., Wong, R. J., Shaw, G. M., Stevenson, D. K., Gaudilliere, B. n., Aghaeepour, N. n., Angst, M. S. 2021: 1–8


    Early identification of pregnant women at risk for preeclampsia (PE) is important, as it will enable targeted interventions ahead of clinical manifestations. The quantitative analyses of plasma proteins feature prominently among molecular approaches used for risk prediction. However, derivation of protein signatures of sufficient predictive power has been challenging. The recent availability of platforms simultaneously assessing over 1000 plasma proteins offers broad examinations of the plasma proteome, which may enable the extraction of proteomic signatures with improved prognostic performance in prenatal care.The primary aim of this study was to examine the generalizability of proteomic signatures predictive of PE in two cohorts of pregnant women whose plasma proteome was interrogated with the same highly multiplexed platform. Establishing generalizability, or lack thereof, is critical to devise strategies facilitating the development of clinically useful predictive tests. A second aim was to examine the generalizability of protein signatures predictive of gestational age (GA) in uncomplicated pregnancies in the same cohorts to contrast physiological and pathological pregnancy outcomes.Serial blood samples were collected during the first, second, and third trimesters in 18 women who developed PE and 18 women with uncomplicated pregnancies (Stanford cohort). The second cohort (Detroit), used for comparative analysis, consisted of 76 women with PE and 90 women with uncomplicated pregnancies. Multivariate analyses were applied to infer predictive and cohort-specific proteomic models, which were then tested in the alternate cohort. Gene ontology (GO) analysis was performed to identify biological processes that were over-represented among top-ranked proteins associated with PE.The model derived in the Stanford cohort was highly significant (p = 3.9E-15) and predictive (AUC = 0.96), but failed validation in the Detroit cohort (p = 9.7E-01, AUC = 0.50). Similarly, the model derived in the Detroit cohort was highly significant (p = 1.0E-21, AUC = 0.73), but failed validation in the Stanford cohort (p = 7.3E-02, AUC = 0.60). By contrast, proteomic models predicting GA were readily validated across the Stanford (p = 1.1E-454, R = 0.92) and Detroit cohorts (p = 1.1.E-92, R = 0.92) indicating that the proteomic assay performed well enough to infer a generalizable model across studied cohorts, which makes it less likely that technical aspects of the assay, including batch effects, accounted for observed differences.Results point to a broader issue relevant for proteomic and other omic discovery studies in patient cohorts suffering from a clinical syndrome, such as PE, driven by heterogeneous pathophysiologies. While novel technologies including highly multiplex proteomic arrays and adapted computational algorithms allow for novel discoveries for a particular study cohort, they may not readily generalize across cohorts. A likely reason is that the prevalence of pathophysiologic processes leading up to the "same" clinical syndrome can be distributed differently in different and smaller-sized cohorts. Signatures derived in individual cohorts may simply capture different facets of the spectrum of pathophysiologic processes driving a syndrome. Our findings have important implications for the design of omic studies of a syndrome like PE. They highlight the need for performing such studies in diverse and well-phenotyped patient populations that are large enough to characterize subsets of patients with shared pathophysiologies to then derive subset-specific signatures of sufficient predictive power.

    View details for DOI 10.1080/14767058.2021.1888915

    View details for PubMedID 33653202

  • Integration of mechanistic immunological knowledge into a machine learning pipeline improves predictions NATURE MACHINE INTELLIGENCE Culos, A., Tsai, A. S., Stanley, N., Becker, M., Ghaemi, M. S., McIlwain, D. R., Fallahzadeh, R., Tanada, A., Nassar, H., Espinosa, C., Xenochristou, M., Ganio, E., Peterson, L., Han, X., Stelzer, I. A., Ando, K., Gaudilliere, D., Phongpreecha, T., Maric, I., Chang, A. L., Shaw, G. M., Stevenson, D. K., Bendall, S., Davis, K. L., Fantl, W., Nolan, G. P., Hastie, T., Tibshirani, R., Angst, M. S., Gaudilliere, B., Aghaeepour, N. 2020
  • Integration of mechanistic immunological knowledge into a machine learning pipeline improves predictions. Nature machine intelligence Culos, A., Tsai, A. S., Stanley, N., Becker, M., Ghaemi, M. S., McIlwain, D. R., Fallahzadeh, R., Tanada, A., Nassar, H., Espinosa, C., Xenochristou, M., Ganio, E., Peterson, L., Han, X., Stelzer, I. A., Ando, K., Gaudilliere, D., Phongpreecha, T., Marić, I., Chang, A. L., Shaw, G. M., Stevenson, D. K., Bendall, S., Davis, K. L., Fantl, W., Nolan, G. P., Hastie, T., Tibshirani, R., Angst, M. S., Gaudilliere, B., Aghaeepour, N. 2020; 2 (10): 619-628


    The dense network of interconnected cellular signalling responses that are quantifiable in peripheral immune cells provides a wealth of actionable immunological insights. Although high-throughput single-cell profiling techniques, including polychromatic flow and mass cytometry, have matured to a point that enables detailed immune profiling of patients in numerous clinical settings, the limited cohort size and high dimensionality of data increase the possibility of false-positive discoveries and model overfitting. We introduce a generalizable machine learning platform, the immunological Elastic-Net (iEN), which incorporates immunological knowledge directly into the predictive models. Importantly, the algorithm maintains the exploratory nature of the high-dimensional dataset, allowing for the inclusion of immune features with strong predictive capabilities even if not consistent with prior knowledge. In three independent studies our method demonstrates improved predictions for clinically relevant outcomes from mass cytometry data generated from whole blood, as well as a large simulated dataset. The iEN is available under an open-source licence.

    View details for DOI 10.1038/s42256-020-00232-8

    View details for PubMedID 33294774

    View details for PubMedCentralID PMC7720904

  • Towards personalized medicine in maternal and child health: integrating biologic and social determinants. Pediatric research Stevenson, D. K., Wong, R. J., Aghaeepour, N., Maric, I., Angst, M. S., Contrepois, K., Darmstadt, G. L., Druzin, M. L., Eisenberg, M. L., Gaudilliere, B., Gibbs, R. S., Gotlib, I. H., Gould, J. B., Lee, H. C., Ling, X. B., Mayo, J. A., Moufarrej, M. N., Quaintance, C. C., Quake, S. R., Relman, D. A., Sirota, M., Snyder, M. P., Sylvester, K. G., Hao, S., Wise, P. H., Shaw, G. M., Katz, M. 2020

    View details for DOI 10.1038/s41390-020-0981-8

    View details for PubMedID 32454518

  • Multiomic immune clockworks of pregnancy. Seminars in immunopathology Peterson, L. S., Stelzer, I. A., Tsai, A. S., Ghaemi, M. S., Han, X. n., Ando, K. n., Winn, V. D., Martinez, N. R., Contrepois, K. n., Moufarrej, M. N., Quake, S. n., Relman, D. A., Snyder, M. P., Shaw, G. M., Stevenson, D. K., Wong, R. J., Arck, P. n., Angst, M. S., Aghaeepour, N. n., Gaudilliere, B. n. 2020


    Preterm birth is the leading cause of mortality in children under the age of five worldwide. Despite major efforts, we still lack the ability to accurately predict and effectively prevent preterm birth. While multiple factors contribute to preterm labor, dysregulations of immunological adaptations required for the maintenance of a healthy pregnancy is at its pathophysiological core. Consequently, a precise understanding of these chronologically paced immune adaptations and of the biological pacemakers that synchronize the pregnancy "immune clock" is a critical first step towards identifying deviations that are hallmarks of peterm birth. Here, we will review key elements of the fetal, placental, and maternal pacemakers that program the immune clock of pregnancy. We will then emphasize multiomic studies that enable a more integrated view of pregnancy-related immune adaptations. Such multiomic assessments can strengthen the biological plausibility of immunological findings and increase the power of biological signatures predictive of preterm birth.

    View details for DOI 10.1007/s00281-019-00772-1

    View details for PubMedID 32020337

  • Discovery and validation of biomarkers to aid the development of safe and effective pain therapeutics: challenges and opportunities. Nature reviews. Neurology Davis, K. D., Aghaeepour, N. n., Ahn, A. H., Angst, M. S., Borsook, D. n., Brenton, A. n., Burczynski, M. E., Crean, C. n., Edwards, R. n., Gaudilliere, B. n., Hergenroeder, G. W., Iadarola, M. J., Iyengar, S. n., Jiang, Y. n., Kong, J. T., Mackey, S. n., Saab, C. Y., Sang, C. N., Scholz, J. n., Segerdahl, M. n., Tracey, I. n., Veasley, C. n., Wang, J. n., Wager, T. D., Wasan, A. D., Pelleymounter, M. A. 2020


    Pain medication plays an important role in the treatment of acute and chronic pain conditions, but some drugs, opioids in particular, have been overprescribed or prescribed without adequate safeguards, leading to an alarming rise in medication-related overdose deaths. The NIH Helping to End Addiction Long-term (HEAL) Initiative is a trans-agency effort to provide scientific solutions to stem the opioid crisis. One component of the initiative is to support biomarker discovery and rigorous validation in collaboration with industry leaders to accelerate high-quality clinical research into neurotherapeutics and pain. The use of objective biomarkers and clinical trial end points throughout the drug discovery and development process is crucial to help define pathophysiological subsets of pain, evaluate target engagement of new drugs and predict the analgesic efficacy of new drugs. In 2018, the NIH-led Discovery and Validation of Biomarkers to Develop Non-Addictive Therapeutics for Pain workshop convened scientific leaders from academia, industry, government and patient advocacy groups to discuss progress, challenges, gaps and ideas to facilitate the development of biomarkers and end points for pain. The outcomes of this workshop are outlined in this Consensus Statement.

    View details for DOI 10.1038/s41582-020-0362-2

    View details for PubMedID 32541893

  • A longitudinal study of the post-stroke immune response and cognitive functioning: the StrokeCog study protocol. BMC neurology Drag, L. L., Mlynash, M. n., Nassar, H. n., Osborn, E. n., Kim, D. E., Angst, M. S., Aghaeepour, N. n., Buckwalter, M. n., Lansberg, M. G. 2020; 20 (1): 313


    Stroke increases the risk of cognitive impairment even several years after the stroke event. The exact mechanisms of post-stroke cognitive decline are unclear, but the immunological response to stroke might play a role. The aims of the StrokeCog study are to examine the associations between immunological responses and long-term post-stroke cognitive trajectories in individuals with ischemic stroke.StrokeCog is a single-center, prospective, observational, cohort study. Starting 6-12 months after stroke, comprehensive neuropsychological assessment, plasma and serum, and psychosocial variables will be collected at up to 4 annual visits. Single cell sequencing of peripheral blood monocytes and plasma proteomics will be conducted. The primary outcome will be the change in global and domain-specific neuropsychological performance across annual evaluations. To explain the differences in cognitive change amongst participants, we will examine the relationships between comprehensive immunological measures and these cognitive trajectories. It is anticipated that 210 participants will be enrolled during the first 3 years of this 4-year study. Accounting for attrition, an anticipated final sample size of 158 participants with an average of 3 annual study visits will be available at the completion of the study. Power analyses indicate that this sample size will provide 90% power to detect an average cognitive change of at least 0.23 standard deviations in either direction.StrokeCog will provide novel insight into the relationships between immune events and cognitive change late after stroke.

    View details for DOI 10.1186/s12883-020-01897-9

    View details for PubMedID 32847540

  • Systematic Immunophenotyping Reveals Sex-Specific Responses After Painful Injury in Mice. Frontiers in immunology Tawfik, V. L., Huck, N. A., Baca, Q. J., Ganio, E. A., Haight, E. S., Culos, A. n., Ghaemi, S. n., Phongpreecha, T. n., Angst, M. S., Clark, J. D., Aghaeepour, N. n., Gaudilliere, B. n. 2020; 11: 1652


    Many diseases display unequal prevalence between sexes. The sex-specific immune response to both injury and persistent pain remains underexplored and would inform treatment paradigms. We utilized high-dimensional mass cytometry to perform a comprehensive analysis of phenotypic and functional immune system differences between male and female mice after orthopedic injury. Multivariate modeling of innate and adaptive immune cell responses after injury using an elastic net algorithm, a regularized regression method, revealed sex-specific divergence at 12 h and 7 days after injury with a stronger immune response to injury in females. At 12 h, females upregulated STAT3 signaling in neutrophils but downregulated STAT1 and STAT6 signals in T regulatory cells, suggesting a lack of engagement of immune suppression pathways by females. Furthermore, at 7 days females upregulated MAPK pathways (p38, ERK, NFkB) in CD4T memory cells, setting up a possible heightened immune memory of painful injury. Taken together, our findings provide the first comprehensive and functional analysis of sex-differences in the immune response to painful injury.

    View details for DOI 10.3389/fimmu.2020.01652

    View details for PubMedID 32849569

    View details for PubMedCentralID PMC7403191

  • Multiomics Characterization of Preterm Birth in Low- and Middle-Income Countries. JAMA network open Jehan, F. n., Sazawal, S. n., Baqui, A. H., Nisar, M. I., Dhingra, U. n., Khanam, R. n., Ilyas, M. n., Dutta, A. n., Mitra, D. K., Mehmood, U. n., Deb, S. n., Mahmud, A. n., Hotwani, A. n., Ali, S. M., Rahman, S. n., Nizar, A. n., Ame, S. M., Moin, M. I., Muhammad, S. n., Chauhan, A. n., Begum, N. n., Khan, W. n., Das, S. n., Ahmed, S. n., Hasan, T. n., Khalid, J. n., Rizvi, S. J., Juma, M. H., Chowdhury, N. H., Kabir, F. n., Aftab, F. n., Quaiyum, A. n., Manu, A. n., Yoshida, S. n., Bahl, R. n., Rahman, A. n., Pervin, J. n., Winston, J. n., Musonda, P. n., Stringer, J. S., Litch, J. A., Ghaemi, M. S., Moufarrej, M. N., Contrepois, K. n., Chen, S. n., Stelzer, I. A., Stanley, N. n., Chang, A. L., Hammad, G. B., Wong, R. J., Liu, C. n., Quaintance, C. C., Culos, A. n., Espinosa, C. n., Xenochristou, M. n., Becker, M. n., Fallahzadeh, R. n., Ganio, E. n., Tsai, A. S., Gaudilliere, D. n., Tsai, E. S., Han, X. n., Ando, K. n., Tingle, M. n., Maric, I. n., Wise, P. H., Winn, V. D., Druzin, M. L., Gibbs, R. S., Darmstadt, G. L., Murray, J. C., Shaw, G. M., Stevenson, D. K., Snyder, M. P., Quake, S. R., Angst, M. S., Gaudilliere, B. n., Aghaeepour, N. n. 2020; 3 (12): e2029655


    Worldwide, preterm birth (PTB) is the single largest cause of deaths in the perinatal and neonatal period and is associated with increased morbidity in young children. The cause of PTB is multifactorial, and the development of generalizable biological models may enable early detection and guide therapeutic studies.To investigate the ability of transcriptomics and proteomics profiling of plasma and metabolomics analysis of urine to identify early biological measurements associated with PTB.This diagnostic/prognostic study analyzed plasma and urine samples collected from May 2014 to June 2017 from pregnant women in 5 biorepository cohorts in low- and middle-income countries (LMICs; ie, Matlab, Bangladesh; Lusaka, Zambia; Sylhet, Bangladesh; Karachi, Pakistan; and Pemba, Tanzania). These cohorts were established to study maternal and fetal outcomes and were supported by the Alliance for Maternal and Newborn Health Improvement and the Global Alliance to Prevent Prematurity and Stillbirth biorepositories. Data were analyzed from December 2018 to July 2019.Blood and urine specimens that were collected early during pregnancy (median sampling time of 13.6 weeks of gestation, according to ultrasonography) were processed, stored, and shipped to the laboratories under uniform protocols. Plasma samples were assayed for targeted measurement of proteins and untargeted cell-free ribonucleic acid profiling; urine samples were assayed for metabolites.The PTB phenotype was defined as the delivery of a live infant before completing 37 weeks of gestation.Of the 81 pregnant women included in this study, 39 had PTBs (48.1%) and 42 had term pregnancies (51.9%) (mean [SD] age of 24.8 [5.3] years). Univariate analysis demonstrated functional biological differences across the 5 cohorts. A cohort-adjusted machine learning algorithm was applied to each biological data set, and then a higher-level machine learning modeling combined the results into a final integrative model. The integrated model was more accurate, with an area under the receiver operating characteristic curve (AUROC) of 0.83 (95% CI, 0.72-0.91) compared with the models derived for each independent biological modality (transcriptomics AUROC, 0.73 [95% CI, 0.61-0.83]; metabolomics AUROC, 0.59 [95% CI, 0.47-0.72]; and proteomics AUROC, 0.75 [95% CI, 0.64-0.85]). Primary features associated with PTB included an inflammatory module as well as a metabolomic module measured in urine associated with the glutamine and glutamate metabolism and valine, leucine, and isoleucine biosynthesis pathways.This study found that, in LMICs and high PTB settings, major biological adaptations during term pregnancy follow a generalizable model and the predictive accuracy for PTB was augmented by combining various omics data sets, suggesting that PTB is a condition that manifests within multiple biological systems. These data sets, with machine learning partnerships, may be a key step in developing valuable predictive tests and intervention candidates for preventing PTB.

    View details for DOI 10.1001/jamanetworkopen.2020.29655

    View details for PubMedID 33337494

  • Author Correction: Preferential inhibition of adaptive immune system dynamics by glucocorticoids in patients after acute surgical trauma. Nature communications Ganio, E. A., Stanley, N. n., Lindberg-Larsen, V. n., Einhaus, J. n., Tsai, A. S., Verdonk, F. n., Culos, A. n., Ghaemi, S. n., Rumer, K. K., Stelzer, I. A., Gaudilliere, D. n., Tsai, E. n., Fallahzadeh, R. n., Choisy, B. n., Kehlet, H. n., Aghaeepour, N. n., Angst, M. S., Gaudilliere, B. n. 2020; 11 (1): 4495


    An amendment to this paper has been published and can be accessed via a link at the top of the paper.

    View details for DOI 10.1038/s41467-020-18410-y

    View details for PubMedID 32883978

  • Changes in pregnancy-related serum biomarkers early in gestation are associated with later development of preeclampsia. PloS one Hao, S. n., You, J. n., Chen, L. n., Zhao, H. n., Huang, Y. n., Zheng, L. n., Tian, L. n., Maric, I. n., Liu, X. n., Li, T. n., Bianco, Y. K., Winn, V. D., Aghaeepour, N. n., Gaudilliere, B. n., Angst, M. S., Zhou, X. n., Li, Y. M., Mo, L. n., Wong, R. J., Shaw, G. M., Stevenson, D. K., Cohen, H. J., Mcelhinney, D. B., Sylvester, K. G., Ling, X. B. 2020; 15 (3): e0230000


    Placental protein expression plays a crucial role during pregnancy. We hypothesized that: (1) circulating levels of pregnancy-associated, placenta-related proteins throughout gestation reflect the temporal progression of the uncomplicated, full-term pregnancy, and can effectively estimate gestational ages (GAs); and (2) preeclampsia (PE) is associated with disruptions in these protein levels early in gestation; and can identify impending PE. We also compared gestational profiles of proteins in the human and mouse, using pregnant heme oxygenase-1 (HO-1) heterozygote (Het) mice, a mouse model reflecting PE-like symptoms.Serum levels of placenta-related proteins-leptin (LEP), chorionic somatomammotropin hormone like 1 (CSHL1), elabela (ELA), activin A, soluble fms-like tyrosine kinase 1 (sFlt-1), and placental growth factor (PlGF)-were quantified by ELISA in blood serially collected throughout human pregnancies (20 normal subjects with 66 samples, and 20 subjects who developed PE with 61 samples). Multivariate analysis was performed to estimate the GA in normal pregnancy. Mean-squared errors of GA estimations were used to identify impending PE. The human protein profiles were then compared with those in the pregnant HO-1 Het mice.An elastic net-based gestational dating model was developed (R2 = 0.76) and validated (R2 = 0.61) using serum levels of the 6 proteins measured at various GAs from women with normal uncomplicated pregnancies. In women who developed PE, the model was not (R2 = -0.17) associated with GA. Deviations from the model estimations were observed in women who developed PE (P = 0.01). The model developed with 5 proteins (ELA excluded) performed similarly from sera from normal human (R2 = 0.68) and WT mouse (R2 = 0.85) pregnancies. Disruptions of this model were observed in both human PE-associated (R2 = 0.27) and mouse HO-1 Het (R2 = 0.30) pregnancies. LEP outperformed sFlt-1 and PlGF in differentiating impending PE at early human and late mouse GAs.Serum placenta-related protein profiles are temporally regulated throughout normal pregnancies and significantly disrupted in women who develop PE. LEP changes earlier than the well-established biomarkers (sFlt-1 and PlGF). There may be evidence of a causative action of HO-1 deficiency in LEP upregulation in a PE-like murine model.

    View details for DOI 10.1371/journal.pone.0230000

    View details for PubMedID 32126118

  • VoPo leverages cellular heterogeneity for predictive modeling of single-cell data. Nature communications Stanley, N. n., Stelzer, I. A., Tsai, A. S., Fallahzadeh, R. n., Ganio, E. n., Becker, M. n., Phongpreecha, T. n., Nassar, H. n., Ghaemi, S. n., Maric, I. n., Culos, A. n., Chang, A. L., Xenochristou, M. n., Han, X. n., Espinosa, C. n., Rumer, K. n., Peterson, L. n., Verdonk, F. n., Gaudilliere, D. n., Tsai, E. n., Feyaerts, D. n., Einhaus, J. n., Ando, K. n., Wong, R. J., Obermoser, G. n., Shaw, G. M., Stevenson, D. K., Angst, M. S., Gaudilliere, B. n., Aghaeepour, N. n. 2020; 11 (1): 3738


    High-throughput single-cell analysis technologies produce an abundance of data that is critical for profiling the heterogeneity of cellular systems. We introduce VoPo (, a machine learning algorithm for predictive modeling and comprehensive visualization of the heterogeneity captured in large single-cell datasets. In three mass cytometry datasets, with the largest measuring hundreds of millions of cells over hundreds of samples, VoPo defines phenotypically and functionally homogeneous cell populations. VoPo further outperforms state-of-the-art machine learning algorithms in classification tasks, and identified immune-correlates of clinically-relevant parameters.

    View details for DOI 10.1038/s41467-020-17569-8

    View details for PubMedID 32719375

  • Pancreatic Surgery Anesthesiologist’s Manual of Surgical Procedures Norton, J. A., Angst, M. S. edited by Jaffe, R. A., Schmiesing, C. A., Golianu, B. Lippincott, Williams & Wilkins. 2020; 6: 687–706
  • Peritoneal Surgery Anesthesiologist’s Manual of Surgical Procedures Norton, J. A., Angst, M. S. edited by Jaffe, R. A., Schmiesing, C. A., Golianu, B. Lippincott, Williams & Wilkins. 2020; 6: 707–728
  • Preferential inhibition of adaptive immune system dynamics by glucocorticoids in patients after acute surgical trauma. Nature communications Ganio, E. A., Stanley, N. n., Lindberg-Larsen, V. n., Einhaus, J. n., Tsai, A. S., Verdonk, F. n., Culos, A. n., Gahemi, S. n., Rumer, K. K., Stelzer, I. A., Gaudilliere, D. n., Tsai, E. n., Fallahzadeh, R. n., Choisy, B. n., Kehlet, H. n., Aghaeepour, N. n., Angst, M. S., Gaudilliere, B. n. 2020; 11 (1): 3737


    Glucocorticoids (GC) are a controversial yet commonly used intervention in the clinical management of acute inflammatory conditions, including sepsis or traumatic injury. In the context of major trauma such as surgery, concerns have been raised regarding adverse effects from GC, thereby necessitating a better understanding of how GCs modulate the immune response. Here we report the results of a randomized controlled trial (NCT02542592) in which we employ a high-dimensional mass cytometry approach to characterize innate and adaptive cell signaling dynamics after a major surgery (primary outcome) in patients treated with placebo or methylprednisolone (MP). A robust, unsupervised bootstrap clustering of immune cell subsets coupled with random forest analysis shows profound (AUC = 0.92, p-value = 3.16E-8) MP-induced alterations of immune cell signaling trajectories, particularly in the adaptive compartments. By contrast, key innate signaling responses previously associated with pain and functional recovery after surgery, including STAT3 and CREB phosphorylation, are not affected by MP. These results imply cell-specific and pathway-specific effects of GCs, and also prompt future studies to examine GCs' effects on clinical outcomes likely dependent on functional adaptive immune responses.

    View details for DOI 10.1038/s41467-020-17565-y

    View details for PubMedID 32719355

  • CytoNorm: A Normalization Algorithm for Cytometry Data. Cytometry. Part A : the journal of the International Society for Analytical Cytology Van Gassen, S., Gaudilliere, B., Angst, M. S., Saeys, Y., Aghaeepour, N. 2019


    High-dimensional flow cytometry has matured to a level that enables deep phenotyping of cellular systems at a clinical scale. The resulting high-content data sets allow characterizing the human immune system at unprecedented single cell resolution. However, the results are highly dependent on sample preparation and measurements might drift over time. While various controls exist for assessment and improvement of data quality in a single sample, the challenges of cross-sample normalization attempts have been limited to aligning marker distributions across subjects. These approaches, inspired by bulk genomics and proteomics assays, ignore the single-cell nature of the data and risk the removal of biologically relevant signals. This work proposes CytoNorm, a normalization algorithm to ensure internal consistency between clinical samples based on shared controls across various study batches. Data from the shared controls is used to learn the appropriate transformations for each batch (e.g., each analysis day). Importantly, some sources of technical variation are strongly influenced by the amount of protein expressed on specific cell types, requiring several population-specific transformations to normalize cells from a heterogeneous sample. To address this, our approach first identifies the overall cellular distribution using a clustering step, and calculates subset-specific transformations on the control samples by computing their quantile distributions and aligning them with splines. These transformations are then applied to all other clinical samples in the batch to remove the batch-specific variations. We evaluated the algorithm on a customized data set with two shared controls across batches. One control sample was used for calculation of the normalization transformations and the second control was used as a blinded test set and evaluated with Earth Mover's distance. Additional results are provided using two real-world clinical data sets. Overall, our method compared favorably to standard normalization procedures. The algorithm is implemented in the R package "CytoNorm" and available via the following link: © 2019 The Authors. Cytometry Part A published by Wiley Periodicals, Inc. on behalf of International Society for Advancement of Cytometry.

    View details for DOI 10.1002/cyto.a.23904

    View details for PubMedID 31633883

  • In Response. Anesthesia and analgesia Berger, M., Angst, M. S., Culley, D. J., Price, C. E., Scott, D. A., Whittington, R. A., Eckenhoff, R. G., Perioperative Neurotoxicity Working Group 2019

    View details for DOI 10.1213/ANE.0000000000004300

    View details for PubMedID 31283620

  • Differential Dynamics of the Maternal Immune System in Healthy Pregnancy and Preeclampsia FRONTIERS IN IMMUNOLOGY Han, X., Ghaemi, M. S., Ando, K., Peterson, L. S., Ganio, E. A., Tsai, A. S., Gaudilliere, D. K., Stelzer, I. A., Einhaus, J., Bertrand, B., Stanley, N., Culos, A., Tanada, A., Hedou, J., Tsai, E. S., Fallahzadeh, R., Wong, R. J., Judy, A. E., Winn, V. D., Druzins, M. L., Blumenfeld, Y. J., Hlatky, M. A., Quaintance, C. C., Gibbs, R. S., Carvalho, B., Shaw, G. M., Stevenson, D. K., Angst, M. S., Aghaeepour, N., Gaudilliere, B. 2019; 10
  • A year-long immune profile of the systemic response in acute stroke survivors. Brain : a journal of neurology Tsai, A. S., Berry, K., Beneyto, M. M., Gaudilliere, D., Ganio, E. A., Culos, A., Ghaemi, M. S., Choisy, B., Djebali, K., Einhaus, J. F., Bertrand, B., Tanada, A., Stanley, N., Fallahzadeh, R., Baca, Q., Quach, L. N., Osborn, E., Drag, L., Lansberg, M. G., Angst, M. S., Gaudilliere, B., Buckwalter, M. S., Aghaeepour, N. 2019


    Stroke is a leading cause of cognitive impairment and dementia, but the mechanisms that underlie post-stroke cognitive decline are not well understood. Stroke produces profound local and systemic immune responses that engage all major innate and adaptive immune compartments. However, whether the systemic immune response to stroke contributes to long-term disability remains ill-defined. We used a single-cell mass cytometry approach to comprehensively and functionally characterize the systemic immune response to stroke in longitudinal blood samples from 24 patients over the course of 1 year and correlated the immune response with changes in cognitive functioning between 90 and 365 days post-stroke. Using elastic net regularized regression modelling, we identified key elements of a robust and prolonged systemic immune response to ischaemic stroke that occurs in three phases: an acute phase (Day 2) characterized by increased signal transducer and activator of transcription 3 (STAT3) signalling responses in innate immune cell types, an intermediate phase (Day 5) characterized by increased cAMP response element-binding protein (CREB) signalling responses in adaptive immune cell types, and a late phase (Day 90) by persistent elevation of neutrophils, and immunoglobulin M+ (IgM+) B cells. By Day 365 there was no detectable difference between these samples and those from an age- and gender-matched patient cohort without stroke. When regressed against the change in the Montreal Cognitive Assessment scores between Days 90 and 365 after stroke, the acute inflammatory phase Elastic Net model correlated with post-stroke cognitive trajectories (r = -0.692, Bonferroni-corrected P = 0.039). The results demonstrate the utility of a deep immune profiling approach with mass cytometry for the identification of clinically relevant immune correlates of long-term cognitive trajectories.

    View details for DOI 10.1093/brain/awz022

    View details for PubMedID 30860258

  • Deep Immune Profiling of the Post-Stroke Peripheral Immune Response Reveals Tri-phasic Response and Correlations With Long-Term Cognitive Outcomes Tsai, A. S., Berry, K., Beneyto, M. M., Gaudilliere, D., Ganio, E. A., Choisy, B., Djebali, K., Baca, Q., Quach, L., Drag, L., Lansberg, M. G., Angst, M. S., Gaudilliere, B., Buckwalter, M. S., Aghaeepour, N. LIPPINCOTT WILLIAMS & WILKINS. 2019
  • Systemic Immunologic Consequences of Chronic Periodontitis. Journal of dental research Gaudilliere, D. K., Culos, A. n., Djebali, K. n., Tsai, A. S., Ganio, E. A., Choi, W. M., Han, X. n., Maghaireh, A. n., Choisy, B. n., Baca, Q. n., Einhaus, J. F., Hedou, J. J., Bertrand, B. n., Ando, K. n., Fallahzadeh, R. n., Ghaemi, M. S., Okada, R. n., Stanley, N. n., Tanada, A. n., Tingle, M. n., Alpagot, T. n., Helms, J. A., Angst, M. S., Aghaeepour, N. n., Gaudilliere, B. n. 2019: 22034519857714


    Chronic periodontitis (ChP) is a prevalent inflammatory disease affecting 46% of the US population. ChP produces a profound local inflammatory response to dysbiotic oral microbiota that leads to destruction of alveolar bone and tooth loss. ChP is also associated with systemic illnesses, including cardiovascular diseases, malignancies, and adverse pregnancy outcomes. However, the mechanisms underlying these adverse health outcomes are poorly understood. In this prospective cohort study, we used a highly multiplex mass cytometry immunoassay to perform an in-depth analysis of the systemic consequences of ChP in patients before (n = 28) and after (n = 16) periodontal treatment. A high-dimensional analysis of intracellular signaling networks revealed immune system-wide dysfunctions differentiating patients with ChP from healthy controls. Notably, we observed exaggerated proinflammatory responses to Porphyromonas gingivalis-derived lipopolysaccharide in circulating neutrophils and monocytes from patients with ChP. Simultaneously, natural killer cell responses to inflammatory cytokines were attenuated. Importantly, the immune alterations associated with ChP were no longer detectable 3 wk after periodontal treatment. Our findings demarcate systemic and cell-specific immune dysfunctions in patients with ChP, which can be temporarily reversed by the local treatment of ChP. Future studies in larger cohorts are needed to test the boundaries of generalizability of our results.

    View details for DOI 10.1177/0022034519857714

    View details for PubMedID 31226001

  • Multiomics modeling of the immunome, transcriptome, microbiome, proteome and metabolome adaptations during human pregnancy. Bioinformatics (Oxford, England) Ghaemi, M. S., DiGiulio, D. B., Contrepois, K., Callahan, B., Ngo, T. T., Lee-McMullen, B., Lehallier, B., Robaczewska, A., Mcilwain, D., Rosenberg-Hasson, Y., Wong, R. J., Quaintance, C., Culos, A., Stanley, N., Tanada, A., Tsai, A., Gaudilliere, D., Ganio, E., Han, X., Ando, K., McNeil, L., Tingle, M., Wise, P., Maric, I., Sirota, M., Wyss-Coray, T., Winn, V. D., Druzin, M. L., Gibbs, R., Darmstadt, G. L., Lewis, D. B., Partovi Nia, V., Agard, B., Tibshirani, R., Nolan, G., Snyder, M. P., Relman, D. A., Quake, S. R., Shaw, G. M., Stevenson, D. K., Angst, M. S., Gaudilliere, B., Aghaeepour, N. 2019; 35 (1): 95–103


    Motivation: Multiple biological clocks govern a healthy pregnancy. These biological mechanisms produce immunologic, metabolomic, proteomic, genomic and microbiomic adaptations during the course of pregnancy. Modeling the chronology of these adaptations during full-term pregnancy provides the frameworks for future studies examining deviations implicated in pregnancy-related pathologies including preterm birth and preeclampsia.Results: We performed a multiomics analysis of 51 samples from 17 pregnant women, delivering at term. The datasets included measurements from the immunome, transcriptome, microbiome, proteome and metabolome of samples obtained simultaneously from the same patients. Multivariate predictive modeling using the Elastic Net (EN) algorithm was used to measure the ability of each dataset to predict gestational age. Using stacked generalization, these datasets were combined into a single model. This model not only significantly increased predictive power by combining all datasets, but also revealed novel interactions between different biological modalities. Future work includes expansion of the cohort to preterm-enriched populations and in vivo analysis of immune-modulating interventions based on the mechanisms identified.Availability and implementation: Datasets and scripts for reproduction of results are available through: information: Supplementary data are available at Bioinformatics online.

    View details for PubMedID 30561547

  • Predicting Acute Pain After Surgery: A Multivariate Analysis. Annals of surgery Baca, Q. n., Marti, F. n., Poblete, B. n., Gaudilliere, B. n., Aghaeepour, N. n., Angst, M. S. 2019


    To identify perioperative practice patterns that predictably impact postoperative pain.Despite significant advances in perioperative medicine, a significant portion of patients still experience severe pain after major surgery. Postoperative pain is associated with serious adverse outcomes that are costly to patients and society.The presented analysis took advantage of a unique observational data set providing unprecedented detailed pharmacological information. The data were collected by PAIN OUT, a multinational registry project established by the European Commission to improve postoperative pain outcomes. A multivariate approach was used to derive and validate a model predictive of pain on postoperative day 1 (POD1) in 1008 patients undergoing back surgery.The predictive and validated model was highly significant (P = 8.9E-15) and identified modifiable practice patterns. Importantly, the number of nonopioid analgesic drug classes administered during surgery predicted decreased pain on POD1. At least 2 different nonopioid analgesic drug classes (cyclooxygenase inhibitors, acetaminophen, nefopam, or metamizol) were required to provide meaningful pain relief (>30%). However, only a quarter of patients received at least 2 nonanalgesic drug classes during surgery. In addition, the use of very short-acting opioids predicted increased pain on POD1, suggesting room for improvement in the perioperative management of these patients. Although the model was highly significant, it only accounted for a relatively small fraction of the observed variance.The presented analysis offers detailed insight into current practice patterns and reveals modifications that can be implemented in today's clinical practice. Our results also suggest that parameters other than those currently studied are relevant for postoperative pain including biological and psychological variables.

    View details for DOI 10.1097/SLA.0000000000003400

    View details for PubMedID 31188202

  • Nociceptive Physiology Pharmacology and Physiology for Anesthesia Riegelhaupt, P. M., Angst, M. S. edited by Hemmings, H. H., Egan, T. D. Elsevier. 2019; 2: 311–331
  • Design Thinking Pain Management: Tools to Improve Human-centered Communication between Patients and Providers Design Thinking Research - Understanding Innovation. Berte, N., Shluzas, L. A., Beigi, B., Albaniel, M., Angst, M. S., Pickham, D., Leifer, L. edited by Meinel, C. Springer Cham. 2019: 179–197
  • Understanding health disparities. Journal of perinatology : official journal of the California Perinatal Association Stevenson, D. K., Wong, R. J., Aghaeepour, N., Angst, M. S., Darmstadt, G. L., DiGiulio, D. B., Druzin, M. L., Gaudilliere, B., Gibbs, R. S., B Gould, J., Katz, M., Li, J., Moufarrej, M. N., Quaintance, C. C., Quake, S. R., Relman, D. A., Shaw, G. M., Snyder, M. P., Wang, X., Wise, P. H. 2018


    Based upon our recent insights into the determinants of preterm birth, which is the leading cause of death in children under five years of age worldwide, we describe potential analytic frameworks that provides both a common understanding and, ultimately the basis for effective, ameliorative action. Our research on preterm birth serves as an example that the framing of any human health condition is a result of complex interactions between the genome and the exposome. New discoveries of the basic biology of pregnancy, such as the complex immunological and signaling processes that dictate the health and length of gestation, have revealed a complexity in the interactions (current and ancestral) between genetic and environmental forces. Understanding of these relationships may help reduce disparities in preterm birth and guide productive research endeavors and ultimately, effective clinical and public health interventions.

    View details for PubMedID 30560947

  • GateFinder: Projection-based Gating Strategy Optimization for Flow and Mass Cytometry. Bioinformatics (Oxford, England) Aghaeepour, N. n., Simonds, E. F., Knapp, D. J., Bruggner, R. n., Sachs, K. n., Culos, A. n., Gherardini, P. F., Samusik, N. n., Fragiadakis, G. n., Bendall, S. n., Gaudilliere, B. n., Angst, M. S., Eaves, C. J., Weiss, W. A., Fantl, W. n., Nolan, G. n. 2018


    High-parameter single-cell technologies can reveal novel cell populations of interest, but studying or validating these populations using lower-parameter methods remains challenging.Here we present GateFinder, an algorithm that enriches high-dimensional cell types with simple, stepwise polygon gates requiring only two markers at a time. A series of case studies of complex cell types illustrates how simplified enrichment strategies can enable more efficient assays, reveal novel biomarkers, and clarify underlying biology.The GateFinder algorithm is implemented as a free and open-source package for BioConductor: or data are available at Bioinformatics online.

    View details for PubMedID 29850785

  • Best Practices for Postoperative Brain Health: Recommendations From the Fifth International Perioperative Neurotoxicity Working Group. Anesthesia and analgesia Berger, M. n., Schenning, K. J., Brown, C. H., Deiner, S. G., Whittington, R. A., Eckenhoff, R. G., Angst, M. S., Avramescu, S. n., Bekker, A. n., Brzezinski, M. n., Crosby, G. n., Culley, D. J., Eckenhoff, M. n., Eriksson, L. I., Evered, L. n., Ibinson, J. n., Kline, R. P., Kofke, A. n., Ma, D. n., Mathew, J. P., Maze, M. n., Orser, B. A., Price, C. C., Scott, D. A., Silbert, B. n., Su, D. n., Terrando, N. n., Wang, D. S., Wei, H. n., Xie, Z. n., Zuo, Z. n. 2018


    As part of the American Society of Anesthesiology Brain Health Initiative goal of improving perioperative brain health for older patients, over 30 experts met at the fifth International Perioperative Neurotoxicity Workshop in San Francisco, CA, in May 2016, to discuss best practices for optimizing perioperative brain health in older adults (ie, >65 years of age). The objective of this workshop was to discuss and develop consensus solutions to improve patient management and outcomes and to discuss what older adults should be told (and by whom) about postoperative brain health risks. Thus, the workshop was provider and patient oriented as well as solution focused rather than etiology focused. For those areas in which we determined that there were limited evidence-based recommendations, we identified knowledge gaps and the types of scientific knowledge and investigations needed to direct future best practice. Because concerns about perioperative neurocognitive injury in pediatric patients are already being addressed by the SmartTots initiative, our workshop discussion (and thus this article) focuses specifically on perioperative cognition in older adults. The 2 main perioperative cognitive disorders that have been studied to date are postoperative delirium and cognitive dysfunction. Postoperative delirium is a syndrome of fluctuating changes in attention and level of consciousness that occurs in 20%-40% of patients >60 years of age after major surgery and inpatient hospitalization. Many older surgical patients also develop postoperative cognitive deficits that typically last for weeks to months, thus referred to as postoperative cognitive dysfunction. Because of the heterogeneity of different tools and thresholds used to assess and define these disorders at varying points in time after anesthesia and surgery, a recent article has proposed a new recommended nomenclature for these perioperative neurocognitive disorders. Our discussion about this topic was organized around 4 key issues: preprocedure consent, preoperative cognitive assessment, intraoperative management, and postoperative follow-up. These 4 issues also form the structure of this document. Multiple viewpoints were presented by participants and discussed at this in-person meeting, and the overall group consensus from these discussions was then drafted by a smaller writing group (the 6 primary authors of this article) into this manuscript. Of course, further studies have appeared since the workshop, which the writing group has incorporated where appropriate. All participants from this in-person meeting then had the opportunity to review, edit, and approve this final manuscript; 1 participant did not approve the final manuscript and asked for his/her name to be removed.

    View details for PubMedID 30303868

  • Oxytocin and Migraine Headache HEADACHE Tzabazis, A., Kori, S., Mechanic, J., Miller, J., Pascual, C., Manering, N., Carson, D., Klukinov, M., Spierings, E., Jacobs, D., Cuellar, J., Frey, W. H., Hanson, L., Angst, M., Yeomans, D. C. 2017; 57: 64-75


    This article reviews material presented at the 2016 Scottsdale Headache Symposium. This presentation provided scientific results and rationale for the use of intranasal oxytocin for the treatment of migraine headache. Results from preclinical experiments are reviewed, including in vitro experiments demonstrating that trigeminal ganglia neurons possess oxytocin receptors and are inhibited by oxytocin. Furthermore, most of these same neurons contain CGRP, the release of which is inhibited by oxytocin. Results are also presented which demonstrate that nasal oxytocin inhibits responses of trigeminal nucleus caudalis neurons to noxious stimulation using either noxious facial shock or nitroglycerin infusion. These studies led to testing the analgesic effect of intranasal oxytocin in episodic migraineurs-studies which did not meet their primary endpoint of pain relief at 2 h, but which were highly informative and led to additional rat studies wherein inflammation was found to dramatically upregulate the number of oxytocin receptors available on trigeminal neurons. This importance of inflammation was supported by a series of in vivo rat behavioral studies, which demonstrated a clear craniofacial analgesic effect when a pre-existing inflammatory injury was present. The significance of inflammation was further solidified by a small single-dose clinical study, which showed analgesic efficacy that was substantially stronger in chronic migraine patients that had not taken an anti-inflammatory drug within 24 h of oxytocin dosing. A follow-on open label study examining effects of one month of intranasal oxytocin dosing did show a reduction in pain, but a more impressive decrease in the frequency of headaches in both chronic and high frequency episodic migraineurs. This study led to a multicountry double blind, placebo controlled study studying whether, over 2 months of dosing, "as needed" dosing of intranasal oxytocin by chronic and high frequency migraineurs would reduce the frequency of their headaches compared to a 1-month baseline period. This study failed to meet its primary endpoint, due to an extraordinarily high placebo rate in the country of most of the patients (Chile), but was also highly informative, showing strong results in other countries and strong post hoc indications of efficacy. The results provide a strong argument for further development of intranasal oxytocin for migraine prophylaxis.

    View details for DOI 10.1111/head.13082

    View details for PubMedID 28485846

  • Human umbilical cord plasma proteins revitalize hippocampal function in aged mice NATURE Castellano, J. M., Mosher, K. I., Abbey, R. J., McBride, A. A., James, M. L., Berdnik, D., Shen, J. C., Zou, B., Xie, X. S., Tingle, M., Hinkson, I. V., Angst, M. S., Wyss-Coray, T. 2017; 544 (7651): 488-?


    Ageing drives changes in neuronal and cognitive function, the decline of which is a major feature of many neurological disorders. The hippocampus, a brain region subserving roles of spatial and episodic memory and learning, is sensitive to the detrimental effects of ageing at morphological and molecular levels. With advancing age, synapses in various hippocampal subfields exhibit impaired long-term potentiation, an electrophysiological correlate of learning and memory. At the molecular level, immediate early genes are among the synaptic plasticity genes that are both induced by long-term potentiation and downregulated in the aged brain. In addition to revitalizing other aged tissues, exposure to factors in young blood counteracts age-related changes in these central nervous system parameters, although the identities of specific cognition-promoting factors or whether such activity exists in human plasma remains unknown. We hypothesized that plasma of an early developmental stage, namely umbilical cord plasma, provides a reservoir of such plasticity-promoting proteins. Here we show that human cord plasma treatment revitalizes the hippocampus and improves cognitive function in aged mice. Tissue inhibitor of metalloproteinases 2 (TIMP2), a blood-borne factor enriched in human cord plasma, young mouse plasma, and young mouse hippocampi, appears in the brain after systemic administration and increases synaptic plasticity and hippocampal-dependent cognition in aged mice. Depletion experiments in aged mice revealed TIMP2 to be necessary for the cognitive benefits conferred by cord plasma. We find that systemic pools of TIMP2 are necessary for spatial memory in young mice, while treatment of brain slices with TIMP2 antibody prevents long-term potentiation, arguing for previously unknown roles for TIMP2 in normal hippocampal function. Our findings reveal that human cord plasma contains plasticity-enhancing proteins of high translational value for targeting ageing- or disease-associated hippocampal dysfunction.

    View details for DOI 10.1038/nature22067

    View details for PubMedID 28424512

  • Multicenter Systems Analysis of Human Blood Reveals Immature Neutrophils in Males and During Pregnancy. Journal of immunology Blazkova, J., Gupta, S., Liu, Y., Gaudilliere, B., Ganio, E. A., Bolen, C. R., Saar-Dover, R., Fragiadakis, G. K., Angst, M. S., Hasni, S., Aghaeepour, N., Stevenson, D., Baldwin, N., Anguiano, E., Chaussabel, D., Altman, M. C., Kaplan, M. J., Davis, M. M., Furman, D. 2017; 198 (6): 2479-2488


    Despite clear differences in immune system responses and in the prevalence of autoimmune diseases between males and females, there is little understanding of the processes involved. In this study, we identified a gene signature of immature-like neutrophils, characterized by the overexpression of genes encoding for several granule-containing proteins, which was found at higher levels (up to 3-fold) in young (20-30 y old) but not older (60 to >89 y old) males compared with females. Functional and phenotypic characterization of peripheral blood neutrophils revealed more mature and responsive neutrophils in young females, which also exhibited an elevated capacity in neutrophil extracellular trap formation at baseline and upon microbial or sterile autoimmune stimuli. The expression levels of the immature-like neutrophil signature increased linearly with pregnancy, an immune state of increased susceptibility to certain infections. Using mass cytometry, we also find increased frequencies of immature forms of neutrophils in the blood of women during late pregnancy. Thus, our findings show novel sex differences in innate immunity and identify a common neutrophil signature in males and in pregnant women.

    View details for DOI 10.4049/jimmunol.1601855

    View details for PubMedID 28179497

  • Deep Immune Profiling of an Arginine-Enriched Nutritional Intervention in Patients Undergoing Surgery. Journal of immunology (Baltimore, Md. : 1950) Aghaeepour, N. n., Kin, C. n., Ganio, E. A., Jensen, K. P., Gaudilliere, D. K., Tingle, M. n., Tsai, A. n., Lancero, H. L., Choisy, B. n., McNeil, L. S., Okada, R. n., Shelton, A. A., Nolan, G. P., Angst, M. S., Gaudilliere, B. L. 2017


    Application of high-content immune profiling technologies has enormous potential to advance medicine. Whether these technologies reveal pertinent biology when implemented in interventional clinical trials is an important question. The beneficial effects of preoperative arginine-enriched dietary supplements (AES) are highly context specific, as they reduce infection rates in elective surgery, but possibly increase morbidity in critically ill patients. This study combined single-cell mass cytometry with the multiplex analysis of relevant plasma cytokines to comprehensively profile the immune-modifying effects of this much-debated intervention in patients undergoing surgery. An elastic net algorithm applied to the high-dimensional mass cytometry dataset identified a cross-validated model consisting of 20 interrelated immune features that separated patients assigned to AES from controls. The model revealed wide-ranging effects of AES on innate and adaptive immune compartments. Notably, AES increased STAT1 and STAT3 signaling responses in lymphoid cell subsets after surgery, consistent with enhanced adaptive mechanisms that may protect against postsurgical infection. Unexpectedly, AES also increased ERK and P38 MAPK signaling responses in monocytic myeloid-derived suppressor cells, which was paired with their pronounced expansion. These results provide novel mechanistic arguments as to why AES may exert context-specific beneficial or adverse effects in patients with critical illness. This study lays out an analytical framework to distill high-dimensional datasets gathered in an interventional clinical trial into a fairly simple model that converges with known biology and provides insight into novel and clinically relevant cellular mechanisms.

    View details for PubMedID 28794234

  • An immune clock of human pregnancy. Science immunology Aghaeepour, N. n., Ganio, E. A., Mcilwain, D. n., Tsai, A. S., Tingle, M. n., Van Gassen, S. n., Gaudilliere, D. K., Baca, Q. n., McNeil, L. n., Okada, R. n., Ghaemi, M. S., Furman, D. n., Wong, R. J., Winn, V. D., Druzin, M. L., El-Sayed, Y. Y., Quaintance, C. n., Gibbs, R. n., Darmstadt, G. L., Shaw, G. M., Stevenson, D. K., Tibshirani, R. n., Nolan, G. P., Lewis, D. B., Angst, M. S., Gaudilliere, B. n. 2017; 2 (15)


    The maintenance of pregnancy relies on finely tuned immune adaptations. We demonstrate that these adaptations are precisely timed, reflecting an immune clock of pregnancy in women delivering at term. Using mass cytometry, the abundance and functional responses of all major immune cell subsets were quantified in serial blood samples collected throughout pregnancy. Cell signaling-based Elastic Net, a regularized regression method adapted from the elastic net algorithm, was developed to infer and prospectively validate a predictive model of interrelated immune events that accurately captures the chronology of pregnancy. Model components highlighted existing knowledge and revealed previously unreported biology, including a critical role for the interleukin-2-dependent STAT5ab signaling pathway in modulating T cell function during pregnancy. These findings unravel the precise timing of immunological events occurring during a term pregnancy and provide the analytical framework to identify immunological deviations implicated in pregnancy-related pathologies.

    View details for PubMedID 28864494

  • Deep Immune Profiling in Trauma and Sepsis: Flow Is the Way to Go! Critical care medicine Gaudilliere, B. n., Angst, M. S., Hotchkiss, R. S. 2017; 45 (9): 1577–78

    View details for PubMedID 28816846

  • A Proteomic Clock of Human Pregnancy. American journal of obstetrics and gynecology Aghaeepour, N. n., Lehallier, B. n., Baca, Q. n., Ganio, E. A., Wong, R. J., Ghaemi, M. S., Culos, A. n., El-Sayed, Y. Y., Blumenfeld, Y. J., Druzin, M. L., Winn, V. D., Gibbs, R. S., Tibshirani, R. n., Shaw, G. M., Stevenson, D. K., Gaudilliere, B. n., Angst, M. S. 2017


    Early detection of maladaptive processes underlying pregnancy-related pathologies is desirable, as it will enable targeted interventions ahead of clinical manifestations. The quantitative analysis of plasma proteins features prominently among molecular approaches used to detect deviations from normal pregnancy. However, derivation of proteomic signatures sufficiently predictive of pregnancy-related outcomes has been challenging. An important obstacle hindering such efforts were limitations in assay technology, which prevented the broad examination of the plasma proteome.The recent availability of a highly-multiplexed platform affording the simultaneous measurement of 1,310 plasma proteins opens the door for a more explorative approach. The major aim of this study was to examine whether analysis of plasma collected during gestation of term pregnancy would allow identifying a set of proteins that tightly track gestational age. Establishing precisely-timed plasma proteomic changes during term pregnancy is a critical step in identifying deviations from regular patterns due to fetal and maternal maladaptations. A second aim was to gain insight into functional attributes of identified proteins, and link such attributes to relevant immunological changes.Pregnant women participated in this longitudinal study. In two subsequent subsets of 21 (training cohort) and 10 (validation cohort) women, specific blood specimens were collected during the first (7-14 wks), second (15-20 wks), and third (24-32 wks) trimesters, and 6 wks post-partum for analysis with a highly-multiplexed aptamer-based platform. An elastic net algorithm was applied to infer a proteomic model predicting gestational age. A bootstrapping procedure and piece-wise regression analysis was used to extract the minimum number of proteins required for predicting gestational age without compromising predictive power. Gene ontology analysis was applied to infer enrichment of molecular functions among proteins included in the proteomic model. Changes in abundance of proteins with such functions were linked to immune features predictive of gestational age at the time of sampling in pregnancies delivering at term.An independently validated model consisting of 74 proteins strongly predicted gestational age (p = 3.8x10-14, R = 0.97). The model could be reduced to eight proteins without losing its predictive power (p = 1.7x10-3, R = 0.91). The three top ranked proteins were glypican 3, chorionic somatomammotropin hormone, and granulins. Proteins activating the Janus kinase (JAK) and signal transducer and activator of transcription (STAT) pathway were enriched in the proteomic model, chorionic somatomammotropin hormone being the top ranked protein. Abundance of chorionic somatomammotropin hormone strongly correlated with STAT5 signaling activity in CD4 T cells, the endogenous cell-signaling event most predictive of gestational age.Results indicate that precisely timed changes in the plasma proteome during term pregnancy mirror a "proteomic clock". Importantly, the combined use of several plasma proteins was required for accurate prediction. The exciting promise of such a "clock" is that deviations from its regular chronological profile may assist in the early diagnoses of pregnancy-relate pathologies and point to underlying pathophysiology. Functional analysis of the proteomic model generated the novel hypothesis that somatomammotropin hormone may critically regulate T-cell function during pregnancy.

    View details for PubMedID 29277631

  • Risky Business: Meeting the Structural Needs of Transdisciplinary Science. The Journal of pediatrics Wise, P. H., Shaw, G. M., Druzin, M. L., Darmstadt, G. L., Quaintance, C. n., Mäkinen, E. n., Relman, D. A., Quake, S. R., Butte, A. J., Angst, M. S., Muglia, L. J., Macones, G. n., Driscoll, D. n., Ober, C. n., Simpson, J. L., Katz, M. n., Howse, J. n., Stevenson, D. K. 2017; 191: 255–58

    View details for PubMedID 29173314

  • Mapping the Fetomaternal Peripheral Immune System at Term Pregnancy. Journal of immunology Fragiadakis, G. K., Baca, Q. J., Gherardini, P. F., Ganio, E. A., Gaudilliere, D. K., Tingle, M., Lancero, H. L., McNeil, L. S., Spitzer, M. H., Wong, R. J., Shaw, G. M., Darmstadt, G. L., Sylvester, K. G., Winn, V. D., Carvalho, B., Lewis, D. B., Stevenson, D. K., Nolan, G. P., Aghaeepour, N., Angst, M. S., Gaudilliere, B. L. 2016


    Preterm labor and infections are the leading causes of neonatal deaths worldwide. During pregnancy, immunological cross talk between the mother and her fetus is critical for the maintenance of pregnancy and the delivery of an immunocompetent neonate. A precise understanding of healthy fetomaternal immunity is the important first step to identifying dysregulated immune mechanisms driving adverse maternal or neonatal outcomes. This study combined single-cell mass cytometry of paired peripheral and umbilical cord blood samples from mothers and their neonates with a graphical approach developed for the visualization of high-dimensional data to provide a high-resolution reference map of the cellular composition and functional organization of the healthy fetal and maternal immune systems at birth. The approach enabled mapping of known phenotypical and functional characteristics of fetal immunity (including the functional hyperresponsiveness of CD4(+) and CD8(+) T cells and the global blunting of innate immune responses). It also allowed discovery of new properties that distinguish the fetal and maternal immune systems. For example, examination of paired samples revealed differences in endogenous signaling tone that are unique to a mother and her offspring, including increased ERK1/2, MAPK-activated protein kinase 2, rpS6, and CREB phosphorylation in fetal Tbet(+)CD4(+) T cells, CD8(+) T cells, B cells, and CD56(lo)CD16(+) NK cells and decreased ERK1/2, MAPK-activated protein kinase 2, and STAT1 phosphorylation in fetal intermediate and nonclassical monocytes. This highly interactive functional map of healthy fetomaternal immunity builds the core reference for a growing data repository that will allow inferring deviations from normal associated with adverse maternal and neonatal outcomes.

    View details for PubMedID 27793998

  • Oxytocin receptor: Expression in the trigeminal nociceptive system and potential role in the treatment of headache disorders. Cephalalgia Tzabazis, A., Mechanic, J., Miller, J., Klukinov, M., Pascual, C., Manering, N., Carson, D. S., Jacobs, A., Qiao, Y., Cuellar, J., Frey, W. H., Jacobs, D., Angst, M., Yeomans, D. C. 2016; 36 (10): 943-950


    Our studies investigated the location of oxytocin receptors in the peripheral trigeminal sensory system and determined their role in trigeminal pain.Oxytocin receptor expression and co-localization with calcitonin gene-related peptide was investigated in rat trigeminal ganglion using immunohistochemistry. Enzyme-linked immunosorbent assay was used to determine the effects of facial electrocutaneous stimulation and adjuvant-induced inflammation of the temporomandibular joint on oxytocin receptor expression in the trigeminal ganglion. Finally, the effects of oxytocin on capsaicin-induced calcitonin gene-related peptide release from dural nociceptors were investigated using isolated rat dura mater.Oxytocin receptor immunoreactivity was present in rat trigeminal neurons. The vast majority of oxytocin receptor immunoreactive neurons co-expressed calcitonin gene-related peptide. Both electrocutaneous stimulation and adjuvant-induced inflammation led to a rapid upregulation of oxytocin receptor protein expression in trigeminal ganglion neurons. Oxytocin significantly and dose-dependently decreased capsaicin-induced calcitonin gene-related peptide release from dural nociceptors.Oxytocin receptor expression in calcitonin gene-related peptide containing trigeminal ganglion neurons, and the blockade of calcitonin gene-related peptide release from trigeminal dural afferents suggests that activation of these receptors may provide therapeutic benefit in patients with migraine and other primary headache disorders.

    View details for DOI 10.1177/0333102415618615

    View details for PubMedID 26590611

  • Patient phenotyping in clinical trials of chronic pain treatments: IMMPACT recommendations PAIN Edwards, R. R., Dworkin, R. H., Turk, D. C., Angst, M. S., Dionne, R., Freeman, R., Hansson, P., Haroutounian, S., Arendt-Nielsen, L., Attal, N., Baron, R., Brell, J., Bujanover, S., Burke, L. B., Carr, D., Chappell, A. S., Cowan, P., Etropolski, M., Fillingim, R. B., Gewandter, J. S., Katz, N. P., Kopecky, E. A., Markman, J. D., Nomikos, G., Porter, L., Rappaport, B. A., Rice, A. S., Scavone, J. M., Scholz, J., Simon, L. S., Smith, S. M., Tobias, J., Tockarshewsky, T., Veasley, C., Versavel, M., Wasan, A. D., Wen, W., Yarnitsky, D. 2016; 157 (9): 1851-1871


    There is tremendous interpatient variability in the response to analgesic therapy (even for efficacious treatments), which can be the source of great frustration in clinical practice. This has led to calls for "precision medicine" or personalized pain therapeutics (ie, empirically based algorithms that determine the optimal treatments, or treatment combinations, for individual patients) that would presumably improve both the clinical care of patients with pain and the success rates for putative analgesic drugs in phase 2 and 3 clinical trials. However, before implementing this approach, the characteristics of individual patients or subgroups of patients that increase or decrease the response to a specific treatment need to be identified. The challenge is to identify the measurable phenotypic characteristics of patients that are most predictive of individual variation in analgesic treatment outcomes, and the measurement tools that are best suited to evaluate these characteristics. In this article, we present evidence on the most promising of these phenotypic characteristics for use in future research, including psychosocial factors, symptom characteristics, sleep patterns, responses to noxious stimulation, endogenous pain-modulatory processes, and response to pharmacologic challenge. We provide evidence-based recommendations for core phenotyping domains and recommend measures of each domain.

    View details for DOI 10.1097/j.pain.0000000000000602

    View details for Web of Science ID 000386014700003

    View details for PubMedID 27152687

  • In Reply. Anesthesiology Angst, M. S., Fragiadakis, G. K., Gaudillière, B., Aghaeepour, N., Nolan, G. P. 2016; 124 (6): 1414-1415

    View details for DOI 10.1097/ALN.0000000000001091

    View details for PubMedID 27187126

  • Patient-specific Immune States before Surgery Are Strong Correlates of Surgical Recovery ANESTHESIOLOGY Fragiadakis, G. K., Gaudilliere, B., Ganio, E. A., Aghaeepour, N., Tingle, M., Nolan, G. P., Angst, M. S. 2015; 123 (6): 1241-1255


    Recovery after surgery is highly variable. Risk-stratifying patients based on their predicted recovery profile will afford individualized perioperative management strategies. Recently, application of mass cytometry in patients undergoing hip arthroplasty revealed strong immune correlates of surgical recovery in blood samples collected shortly after surgery. However, the ability to interrogate a patient's immune state before surgery and predict recovery is highly desirable in perioperative medicine.To evaluate a patient's presurgical immune state, cell-type-specific intracellular signaling responses to ex vivo ligands (lipopolysaccharide, interleukin [IL]-6, IL-10, and IL-2/granulocyte macrophage colony-stimulating factor) were quantified by mass cytometry in presurgical blood samples. Selected ligands modulate signaling processes perturbed by surgery. Twenty-three cell surface and 11 intracellular markers were used for the phenotypic and functional characterization of major immune cell subsets. Evoked immune responses were regressed against patient-centered outcomes, contributing to protracted recovery including functional impairment, postoperative pain, and fatigue.Evoked signaling responses varied significantly and defined patient-specific presurgical immune states. Eighteen signaling responses correlated significantly with surgical recovery parameters (|R| = 0.37 to 0.70; false discovery rate < 0.01). Signaling responses downstream of the toll-like receptor 4 in cluster of differentiation (CD) 14 monocytes were particularly strong correlates, accounting for 50% of observed variance. Immune correlates identified in presurgical blood samples mirrored correlates identified in postsurgical blood samples.Convergent findings in pre- and postsurgical analyses provide validation of reported immune correlates and suggest a critical role of the toll-like receptor 4 signaling pathway in monocytes for the clinical recovery process. The comprehensive assessment of patients' preoperative immune state is promising for predicting important recovery parameters and may lead to clinical tests using standard flow cytometry.

    View details for DOI 10.1097/ALN.0000000000000887

    View details for PubMedID 26655308

  • Implementing Mass Cytometry at the Bedside to Study the Immunological Basis of Human Diseases: Distinctive Immune Features in Patients with a History of Term or Preterm Birth CYTOMETRY PART A Gaudilliere, B., Ganio, E. A., Tingle, M., Lancero, H. L., Fragiadakis, G. K., Baca, Q. J., Aghaeepour, N., Wong, R. J., Quaintance, C., El-Sayed, Y. Y., Shaw, G. M., Lewis, D. B., Stevenson, D. K., Nolan, G. P., Angst, M. S. 2015; 87A (9): 817-829


    Single-cell technologies have immense potential to shed light on molecular and biological processes that drive human diseases. Mass cytometry (or Cytometry by Time Of Flight mass spectrometry, CyTOF) has already been employed in clinical studies to comprehensively survey patients' circulating immune system. As interest in the "bedside" application of mass cytometry is growing, the delineation of relevant methodological issues is called for. This report uses a newly generated dataset to discuss important methodological considerations when mass cytometry is implemented in a clinical study. Specifically, the use of whole blood samples versus peripheral blood mononuclear cells (PBMCs), design of mass-tagged antibody panels, technical and analytical implications of sample barcoding, and application of traditional and unsupervised approaches to analyze high-dimensional mass cytometry datasets are discussed. A mass cytometry assay was implemented in a cross-sectional study of 19 women with a history of term or preterm birth to determine whether immune traits in peripheral blood differentiate the two groups in the absence of pregnancy. Twenty-seven phenotypic and 11 intracellular markers were simultaneously analyzed in whole blood samples stimulated with lipopolysaccharide (LPS at 0, 0.1, 1, 10, and 100 ng mL(-1) ) to examine dose-dependent signaling responses within the toll-like receptor 4 (TLR4) pathway. Complementary analyses, grounded in traditional or unsupervised gating strategies of immune cell subsets, indicated that the prpS6 and pMAPKAPK2 responses in classical monocytes are accentuated in women with a history of preterm birth (FDR<1%). The results suggest that women predisposed to preterm birth may be prone to mount an exacerbated TLR4 response during the course of pregnancy. This important hypothesis-generating finding points to the power of single-cell mass cytometry to detect biologically important differences in a relatively small patient cohort. © 2015 International Society for Advancement of Cytometry.

    View details for DOI 10.1002/cyto.a.22720

    View details for Web of Science ID 000360590500009

  • Intraoperative Use of Remifentanil for TIVA: Postoperative Pain, Acute Tolerance, and Opioid-Induced Hyperalgesia JOURNAL OF CARDIOTHORACIC AND VASCULAR ANESTHESIA Angst, M. S. 2015; 29: S16-S22
  • Editorial comment: challenges in the perioperative management of the patient receiving extended-release naltrexone. A & A case reports Angst, M. S. 2014; 3 (11): 145-?

    View details for DOI 10.1213/XAA.0000000000000104

    View details for PubMedID 25612100

  • Clinical recovery from surgery correlates with single-cell immune signatures. Science translational medicine Gaudillière, B., Fragiadakis, G. K., Bruggner, R. V., Nicolau, M., Finck, R., Tingle, M., Silva, J., Ganio, E. A., Yeh, C. G., Maloney, W. J., Huddleston, J. I., Goodman, S. B., Davis, M. M., Bendall, S. C., Fantl, W. J., Angst, M. S., Nolan, G. P. 2014; 6 (255): 255ra131-?


    Delayed recovery from surgery causes personal suffering and substantial societal and economic costs. Whether immune mechanisms determine recovery after surgical trauma remains ill-defined. Single-cell mass cytometry was applied to serial whole-blood samples from 32 patients undergoing hip replacement to comprehensively characterize the phenotypic and functional immune response to surgical trauma. The simultaneous analysis of 14,000 phosphorylation events in precisely phenotyped immune cell subsets revealed uniform signaling responses among patients, demarcating a surgical immune signature. When regressed against clinical parameters of surgical recovery, including functional impairment and pain, strong correlations were found with STAT3 (signal transducer and activator of transcription), CREB (adenosine 3',5'-monophosphate response element-binding protein), and NF-κB (nuclear factor κB) signaling responses in subsets of CD14(+) monocytes (R = 0.7 to 0.8, false discovery rate <0.01). These sentinel results demonstrate the capacity of mass cytometry to survey the human immune system in a relevant clinical context. The mechanistically derived immune correlates point to diagnostic signatures, and potential therapeutic targets, that could postoperatively improve patient recovery.

    View details for DOI 10.1126/scitranslmed.3009701

    View details for PubMedID 25253674

  • Pancreatic Surgery Anesthesiologist’s Manual of Surgical Procedures Norton, J. A., Angst, M. S. edited by Jaffe, R. A., Schmiesing, C. A., Golianu, B. Lippincott, Williams & Wilkins. 2014; 5: 623–638
  • Peritoneal Surgery Anesthesiologist’s Manual of Surgical Procedures Norton, J. A., Angst, M. S. edited by Jaffe, R. A., Schmiesing, C. A., Golianu, B. Lippincott, Williams & Wilkins. 2014; 5
  • Analgesic and sympatholytic effects of low-dose intrathecal clonidine compared with bupivacaine: a doseresponse study in female volunteers BRITISH JOURNAL OF ANAESTHESIA Ginosar, Y., Riley, E. T., Angst, M. S. 2013; 111 (2): 256-?


    BACKGROUND: /st>A wide range of doses has been suggested for intrathecal clonidine, but no dose-ranging study has examined analgesic effects below 100 µg. The primary aim of this volunteer study was to assess the dose vs analgesic effect relationship for doses of intrathecal clonidine below 100 µg. METHODS: /st>After IRB approval and signed informed consent, 11 healthy female volunteers participated in this randomized, double-blinded, cross-over study using a dose-ranging sparse-sampling technique. Participants received intrathecal clonidine (doses 0-100 µg; n=10) and intrathecal bupivacaine (doses 0-8.8 mg; n=9) on separate study days. At baseline, 30, and 60 min from drug administration, experimental heat pain tolerance was assessed at both a lumbar and a cranial dermatome. Heat and cold perception thresholds were assessed at the same time intervals. Heart rate (HR), arterial pressure, and forearm-finger and toe-leg cutaneous temperature gradients (Tfinger-arm and Ttoe-leg) were used as measures of sympatholysis. RESULTS: /st>Both intrathecal clonidine and bupivacaine caused significant, dose-dependent analgesic effects at the leg but not the head. Significant analgesia to experimental heat pain was detected above 25 µg clonidine and 3 mg bupivacaine. Administration of bupivacaine but not clonidine resulted in a significant dose-related decrease in HR and Ttoe-leg; neither drug caused dose-related sympatholytic effects in the doses used. CONCLUSIONS: /st>After 50 µg clonidine or 5 mg bupivacaine, the heat pain tolerance increased by ∼1°C, similar to the analgesic effect of 5 mg epidural morphine or 30 µg epidural fentanyl in previous studies using this experimental heat pain model. Our results provide additional data for rational dose selection of intrathecal clonidine.

    View details for DOI 10.1093/bja/aet027

    View details for Web of Science ID 000322337900001

    View details for PubMedID 23533254

  • Changes resembling complex regional pain syndrome following surgery and immobilization. journal of pain Pepper, A., Li, W., Kingery, W. S., Angst, M. S., Curtin, C. M., Clark, J. D. 2013; 14 (5): 516-524


    The study of complex regional pain syndrome (CRPS) in humans is complicated by inhomogeneities in available study cohorts. We hoped to characterize early CRPS-like features in patients undergoing hand surgery. Forty-three patients were recruited from a hand surgery clinic that had elective surgeries followed by cast immobilization. On the day of cast removal, patients were assessed for vasomotor, sudomotor, and trophic changes, and edema and pain sensitization using quantitative sensory testing. Pain intensity was assessed at the time of cast removal and after 1 additional month, as was the nature of the pain using the Leeds Assessment of Neuropathic Symptoms and Signs (LANSS). Skin biopsies were harvested for the analysis of expression of inflammatory mediators. We identified vascular and trophic changes in the surgical hands of most patients. Increased sensitivity to punctate, pressure, and cold stimuli were observed commonly as well. Moreover, levels of IL-6, TNF-alpha, and the mast cell marker tryptase were elevated in the skin of hands ipsilateral to surgery. Moderate-to-severe pain persisted in the surgical hands for up to 1 month after cast removal. Exploratory analyses suggested interrelationships between the physical, quantitative sensory testing, and gene expression changes and pain-related outcomes.This study has identified CPRS-like features in the limbs of patients undergoing surgery followed by immobilization. Further studies using this population may be useful in refining our understanding of CRPS mechanisms and treatments for this condition.

    View details for DOI 10.1016/j.jpain.2013.01.004

    View details for PubMedID 23453564

  • Bayesian methods to determine performance differences and to quantify variability among centers in multi-center trials: the IHAST trial BMC MEDICAL RESEARCH METHODOLOGY Bayman, E. O., Chaloner, K. M., Hindman, B. J., Todd, M. M. 2013; 13


    To quantify the variability among centers and to identify centers whose performance are potentially outside of normal variability in the primary outcome and to propose a guideline that they are outliers.Novel statistical methodology using a Bayesian hierarchical model is used. Bayesian methods for estimation and outlier detection are applied assuming an additive random center effect on the log odds of response: centers are similar but different (exchangeable). The Intraoperative Hypothermia for Aneurysm Surgery Trial (IHAST) is used as an example. Analyses were adjusted for treatment, age, gender, aneurysm location, World Federation of Neurological Surgeons scale, Fisher score and baseline NIH stroke scale scores. Adjustments for differences in center characteristics were also examined. Graphical and numerical summaries of the between-center standard deviation (sd) and variability, as well as the identification of potential outliers are implemented.In the IHAST, the center-to-center variation in the log odds of favorable outcome at each center is consistent with a normal distribution with posterior sd of 0.538 (95% credible interval: 0.397 to 0.726) after adjusting for the effects of important covariates. Outcome differences among centers show no outlying centers. Four potential outlying centers were identified but did not meet the proposed guideline for declaring them as outlying. Center characteristics (number of subjects enrolled from the center, geographical location, learning over time, nitrous oxide, and temporary clipping use) did not predict outcome, but subject and disease characteristics did.Bayesian hierarchical methods allow for determination of whether outcomes from a specific center differ from others and whether specific clinical practices predict outcome, even when some centers/subgroups have relatively small sample sizes. In the IHAST no outlying centers were found. The estimated variability between centers was moderately large.

    View details for DOI 10.1186/1471-2288-13-5

    View details for Web of Science ID 000316227900001

    View details for PubMedID 23324207

    View details for PubMedCentralID PMC3599203

  • In reply. Anesthesiology Angst, M. S., Clark, J. D. 2013; 118 (1): 230-231

    View details for DOI 10.1097/ALN.0b013e318278e4e4

    View details for PubMedID 23249943

  • Nociceptive Physiology Pharmacology and Physiology for Anesthesia Ottestad, E., Angst, M. S. edited by Hemmings, H. C., Egan, T. D. Elsevier. 2013; 1: 235–252
  • Postoperative Subcutaneous Instillation of Low-Dose Ketorolac But Not Hydromorphone Reduces Wound Exudate Concentrations of Interleukin-6 and Interleukin-10 and Improves Analgesia Following Cesarean Delivery JOURNAL OF PAIN Carvalho, B., Lemmens, H. J., Ting, V., Angst, M. S. 2013; 14 (1): 48-56


    The objectives of this study were to test the effects of low-dose ketorolac and hydromorphone added to continuous local anesthetic wound instillation on surgical-site inflammatory mediators, postoperative pain, and opioid consumption. Sixty healthy women undergoing cesarean delivery were enrolled in this randomized, double-blinded study. Patients were randomized to receive a subcutaneous wound instillation of bupivacaine .5% at 10 mg/hour (active control), bupivacaine .5% with ketorolac .6 mg/hour, or bupivacaine .5% with hydromorphone .04 mg/hour for 48 hours postcesarean. Wound exudate was sampled at 4, 24, and 48 hours postcesarean and assayed for interleukins IL-1β, IL-2, IL-6, IL-8, IL-10, and IL-12, tumor necrosis factor (TNF-α), interferon (INF-γ), and granulocyte-macrophage colony stimulating factor (GM-CSF). The addition of ketorolac to bupivacaine significantly decreased IL-6 (P = .012) and IL-10 (P = .005) compared to plain bupivacaine. Ketorolac, but not hydromorphone, was associated with a decrease in pain (P = .018) and analgesic use (P = .020) following cesarean delivery. Our results are compatible with the view that significant analgesics effects are mediated through local modulation of inflammatory events. Low-dose ketorolac administered into surgical wounds exert significant anti-inflammatory and analgesic effects and may be a valuable analgesic alternative to systemic nonsteroidal anti-inflammatories (NSAIDs) but with potentially fewer side effects.This article demonstrates that low-dose ketorolac administered into wounds modulates local inflammatory events, decreases postoperative pain, and reduces opioid consumption. These results suggest that administration of NSAIDs into surgical wounds may be an analgesic alternative to higher systemic dosing of NSAIDs.

    View details for DOI 10.1016/j.jpain.2012.10.002

    View details for PubMedID 23218935

  • Collecting And Measuring Wound Exudate Biochemical Mediators In Surgical Wounds JOVE-JOURNAL OF VISUALIZED EXPERIMENTS Carvalho, B., Clark, D. J., Yeomans, D., Angst, M. S. 2012


    We describe a methodology by which we are able to collect and measure biochemical inflammatory and nociceptive mediators at the surgical wound site. Collecting site-specific biochemical markers is important to understand the relationship between levels in serum and surgical wound, determine any associations between mediator release, pain, analgesic use and other outcomes of interest, and evaluate the effect of systemic and peripheral drug administration on surgical wound biochemistry. This methodology has been applied to healthy women undergoing elective cesarean delivery with spinal anesthesia. We have measured wound exudate and serum mediators at the same time intervals as patient's pain scores and analgesics consumption for up to 48 hours post-cesarean delivery. Using this methodology we have been able to detect various biochemical mediators including nerve growth factor (NGF), prostaglandin E2 (PG-E2) substance P, IL-1β, IL-2, IL-4, IL-6, IL-7, IL-8, IL-10, IL-12, IL-13, IL-17, TNFα, INFγ, G-CSF, GM-CSF, MCP-1 and MIP-1β. Studies applying this human surgical wound bioassay have found no correlations between wound and serum cytokine concentrations or their time-release profile (J Pain. 2008; 9(7):650-7).(1) We also documented the utility of the technique to identify drug-mediated changes in wound cytokine content.

    View details for DOI 10.3791/50133

    View details for Web of Science ID 000209225700056

  • Analgesic tolerance without demonstrable opioid-induced hyperalgesia: a double-blinded, randomized, placebo-controlled trial of sustained-release morphine for treatment of chronic nonradicular low-back pain PAIN Chu, L. F., D'Arcy, N., Brady, C., Zamora, A. K., Young, C. A., Kim, J. E., Clemenson, A. M., Angst, M. S., Clark, J. D. 2012; 153 (8): 1583-1592


    Although often successful in acute settings, long-term use of opioid pain medications may be accompanied by waning levels of analgesic response not readily attributable to advancing underlying disease, necessitating dose escalation to attain pain relief. Analgesic tolerance, and more recently opioid-induced hyperalgesia, have been invoked to explain such declines in opioid effectiveness over time. Because both phenomena result in inadequate analgesia, they are difficult to distinguish in a clinical setting. Patients with otherwise uncomplicated low-back pain were titrated to comfort or dose-limiting side effects in a prospective, randomized, double-blind, placebo-controlled clinical trial using sustained-release morphine or weight-matched placebo capsules for 1 month. A total of 103 patients completed the study, with an average end titration dose of 78 mg morphine/d. After 1 month, the morphine-treated patients developed tolerance to the analgesic effects of remifentanil, but did not develop opioid-induced hyperalgesia. On average, these patients experienced a 42% reduction in analgesic potency. The morphine-treated patients experienced clinically relevant improvements in pain relief, as shown by a 44% reduction in average visual analogue scale pain levels and a 31% improvement in functional ability. The differences in visual analogue scale pain levels (P = .003) and self-reported disability (P = .03) between both treatment groups were statistically significant. After 1 month of oral morphine therapy, patients with chronic low-back pain developed tolerance but not opioid-induced hyperalgesia. Improvements in pain and functional ability were observed.

    View details for DOI 10.1016/j.pain.2012.02.028

    View details for PubMedID 22704854

  • Pain sensitivity and opioid analgesia: A pharmacogenomic twin study PAIN Angst, M. S., Phillips, N. G., Drover, D. R., Tingle, M., Ray, A., Swan, G. E., Lazzeroni, L. C., Clark, J. D. 2012; 153 (7): 1397-1409


    Opioids are the cornerstone medication for the management of moderate to severe pain. Unfortunately, vast inter-individual differences in dose requirements complicate their effective and safe clinical use. Mechanisms underlying such differences are incompletely understood, are likely multifactorial, and include genetic and environmental contributions. While accumulating evidence suggests that variants of several genes account for some of the observed response variance, the relative contribution of these factors remains unknown. This study used a twin paradigm to provide a global estimate of the genetic and environmental contributions to inter-individual differences in pain sensitivity and analgesic opioid effects. Eighty one monozygotic and 31 dizygotic twin pairs successfully underwent a computer-controlled infusion with the μ-opioid agonist alfentanil in a single occasion, randomized, double-blind and placebo-controlled study design. Pain sensitivity and analgesic effects were assessed with experimental heat and cold pressor pain models along with important covariates including demographic factors, depression, anxiety, and sleep quality. Significant heritability was detected for cold pressor pain tolerance and opioid-mediated elevations in heat and cold pressor pain thresholds. Genetic effects accounted for 12-60% of the observed response variance. Significant familial effects accounting for 24-32% of observed variance were detected for heat and cold pressor pain thresholds and opioid-mediated elevation in cold pressor pain tolerance. Significant covariates included age, gender, race, education, and anxiety. Results provide a strong rationale for more detailed molecular genetic studies to elucidate mechanisms underlying inter-individual differences in pain sensitivity and analgesic opioid responses. Such studies will require careful consideration of the studied pain phenotype.

    View details for DOI 10.1016/j.pain.2012.02.022

    View details for PubMedID 22444188

  • Aversive and Reinforcing Opioid Effects A Pharmacogenomic Twin Study ANESTHESIOLOGY Angst, M. S., Lazzeroni, L. C., Phillips, N. G., Drover, D. R., Tingle, M., Ray, A., Swan, G. E., Clark, J. D. 2012; 117 (1): 22-37


    The clinical utility of opioids is limited by adverse drug effects including respiratory depression, sedation, nausea, and pruritus. In addition, abuse of prescription opioids is problematic. Gaining a better understanding of the genetic and environmental mechanisms contributing to an individual's susceptibility to adverse opioid effects is essential to identify patients at risk.A classic twin study paradigm provided estimates for the genetic and familial (genetic and/or shared environment) contribution to acute adverse and affective opioid responses, all secondary outcomes of a larger dataset. One hundred twenty-one twin pairs were recruited in a single occasion, randomized, double-blind, and placebo-controlled study. The μ-opioid receptor agonist alfentanil and saline placebo were administered as target-controlled infusions under carefully monitored laboratory conditions. Measured outcomes included respiratory depression, sedation, nausea, pruritus, drug liking, and drug disliking. Demographic information was collected, and aspects of mood and sleep were evaluated.Significant heritability was detected for respiratory depression (30%), nausea (59%), and drug disliking (36%). Significant familial effects were detected for sedation (29%), pruritus (38%), dizziness (32%), and drug liking (26%). Significant covariates included age, sex, race, ethnicity, education, mood, and depression. Covariates affected sedation, pruritus, drug liking and disliking, and dizziness.This study demonstrates that large-scale efforts to collect quantitative and well-defined opioid response data are not only feasible but also produce data that are suitable for genetic analysis. Genetic, environmental, and demographic factors work together to control adverse and reinforcing opioid responses, but contribute differently to specific responses.

    View details for PubMedID 22713632

  • Sensitivity of gait parameters to the effects of anti-inflammatory and opioid treatments in knee osteoarthritis patients JOURNAL OF ORTHOPAEDIC RESEARCH Boyer, K. A., Angst, M. S., Asay, J., Giori, N. J., Andriacchi, T. P. 2012; 30 (7): 1118-1124


    The study aim was to address the need for objective markers of pain-modifying interventions by testing the hypothesis that selective gait measures of knee joint loading can distinguish differences between non-steroidal anti-inflammatory (NSAID), analgesic treatment (opioid-receptor agonist), and placebo in patients medial knee osteoarthritis (OA). A randomized, single-blind washout, double-blind treatment, double-dummy cross-over trial using three treatment arms placebo, opioid (Oxycodone), and NSAID (Celecoxib) in medial compartment knee OA patients. Six patients with Kellgren-Lawrence radiographic severity grades of 2 or 3 completed six testing sessions (gait and pain assessment) at 2-week intervals. A significant increase was found in the knee total reaction moment and vertical ground reaction force (GRF) for Celecoxib compared to placebo (p=0.005, p=0.003), but not for Oxycodone compared to placebo (p=0.20, p=0.27) treatments. Walking speed was significantly higher for the Celecoxib and Oxycodone compared to placebo treatment (p=0.041 and p=0.031, respectively). Self-reported function (WOMAC scores) was not different among treatments (p>0.05). The changes in total reaction moments and GRFs for only the NSAID suggest that greater increases in joint loading occurs when joint inflammation is treated in addition to pain. The total knee reaction moment, representing the magnitude of the extrinsic moment, appears to be a sensitive marker, more so than self-reported metrics, for evaluating knee OA treatment effects.

    View details for DOI 10.1002/jor.22037

    View details for Web of Science ID 000303810000016

    View details for PubMedID 22179861

  • Integrative Approach to Pain Genetics Identifies Pain Sensitivity Loci across Diseases PLOS COMPUTATIONAL BIOLOGY Ruau, D., Dudley, J. T., Chen, R., Phillips, N. G., Swan, G. E., Lazzeroni, L. C., Clark, J. D., Butte, A. J., Angst, M. S. 2012; 8 (6)


    Identifying human genes relevant for the processing of pain requires difficult-to-conduct and expensive large-scale clinical trials. Here, we examine a novel integrative paradigm for data-driven discovery of pain gene candidates, taking advantage of the vast amount of existing disease-related clinical literature and gene expression microarray data stored in large international repositories. First, thousands of diseases were ranked according to a disease-specific pain index (DSPI), derived from Medical Subject Heading (MESH) annotations in MEDLINE. Second, gene expression profiles of 121 of these human diseases were obtained from public sources. Third, genes with expression variation significantly correlated with DSPI across diseases were selected as candidate pain genes. Finally, selected candidate pain genes were genotyped in an independent human cohort and prospectively evaluated for significant association between variants and measures of pain sensitivity. The strongest signal was with rs4512126 (5q32, ABLIM3, P = 1.3×10⁻¹⁰) for the sensitivity to cold pressor pain in males, but not in females. Significant associations were also observed with rs12548828, rs7826700 and rs1075791 on 8q22.2 within NCALD (P = 1.7×10⁻⁴, 1.8×10⁻⁴, and 2.2×10⁻⁴ respectively). Our results demonstrate the utility of a novel paradigm that integrates publicly available disease-specific gene expression data with clinical data curated from MEDLINE to facilitate the discovery of pain-relevant genes. This data-derived list of pain gene candidates enables additional focused and efficient biological studies validating additional candidates.

    View details for DOI 10.1371/journal.pcbi.1002538

    View details for PubMedID 22685391

  • Modulation of remifentanil-induced postinfusion hyperalgesia by the beta-blocker propranolol in humans PAIN Chu, L. F., Cun, T., Ngai, L. K., Kim, J. E., Zamora, A. K., Young, C. A., Angst, M. S., Clark, D. J. 2012; 153 (5): 974-981


    Acute and chronic exposure to opioids has been associated with hyperalgesia in both animals and humans. A genetic analysis of opioid-induced hyperalgesia in mice linked the β(2)-adrenergic receptor to mechanical sensitization after opioid exposure. In humans, expansion of the area of mechanical hyperalgesia surrounding an experimentally induced lesion after the cessation of remifentanil infusion is a commonly used model of opioid hyperalgesia (remifentanil-induced postinfusion hyperalgesia, RPH). The purpose of our translational study was to test the hypothesis that the β-adrenergic receptor antagonist propranolol modulates the expression of RPH in humans. This double-blinded, randomized, placebo-controlled, crossover study was performed in 10 healthy human volunteers. During test sessions, intracutaneous electrical stimulation was used to generate areas of secondary mechanical hyperalgesia. The area of this sensitization was measured before, during, and after remifentanil infusion. Heat pain sensitivity was also followed. During one test session, subjects received propranolol infusion. We observed an average increase in the areas of secondary mechanical hyperalgesia to 141% of the baseline in subjects infused with remifentanil and placebo (P=0.00040). However, when remifentanil infusion was combined with propranolol, the area of secondary hyperalgesia after terminating remifentanil was not significantly different than the area before beginning the opioid infusion (P=0.13). Thermal hyperalgesia was not observed after remifentanil infusion. Propranolol infusion at the selected dose had minor hemodynamic effects. Concomitant infusion of propranolol with remifentanil prevented the expression of RPH. β-adrenergic receptor blockade may be a useful pharmacological strategy for preventing hyperalgesia in patients exposed to opioids.

    View details for DOI 10.1016/j.pain.2012.01.014

    View details for PubMedID 22365565

  • Sex Differences in Reported Pain Across 11,000 Patients Captured in Electronic Medical Records JOURNAL OF PAIN Ruau, D., Liu, L. Y., Clark, J. D., Angst, M. S., Butte, A. J. 2012; 13 (3): 228-234


    Clinically recorded pain scores are abundant in patient health records but are rarely used in research. The use of this information could help improve clinical outcomes. For example, a recent report by the Institute of Medicine stated that ineffective use of clinical information contributes to undertreatment of patient subpopulations--especially women. This study used diagnosis-associated pain scores from a large hospital database to document sex differences in reported pain. We used de-identified electronic medical records from Stanford Hospital and Clinics for more than 72,000 patients. Each record contained at least 1 disease-associated pain score. We found over 160,000 pain scores in more than 250 primary diagnoses, and analyzed differences in disease-specific pain reported by men and women. After filtering for diagnoses with minimum encounter numbers, we found diagnosis-specific sex differences in reported pain. The most significant differences occurred in patients with disorders of the musculoskeletal, circulatory, respiratory and digestive systems, followed by infectious diseases, and injury and poisoning. We also discovered sex-specific differences in pain intensity in previously unreported diseases, including disorders of the cervical region, and acute sinusitis (P = .01, .017, respectively). Pain scores were collected during hospital encounters. No information about the use of pre-encounter over-the-counter medications was available. To our knowledge, this is the largest data-driven study documenting sex differences of disease-associated pain. It highlights the utility of electronic medical record data to corroborate and expand on results of smaller clinical studies. Our findings emphasize the need for future research examining the mechanisms underlying differences in pain.This article highlights the potential of electronic medical records to conduct large-scale pain studies. Our results are consistent with previous studies reporting pain differences between sexes and also suggest that clinicians should pay increased attention to this idea.

    View details for DOI 10.1016/j.jpain.2011.11.002

    View details for PubMedID 22245360

  • Collecting and measuring wound exudate biochemical mediators in surgical wounds. Journal of visualized experiments : JoVE Carvalho, B., Clark, D. J., Yeomans, D., Angst, M. S. 2012


    We describe a methodology by which we are able to collect and measure biochemical inflammatory and nociceptive mediators at the surgical wound site. Collecting site-specific biochemical markers is important to understand the relationship between levels in serum and surgical wound, determine any associations between mediator release, pain, analgesic use and other outcomes of interest, and evaluate the effect of systemic and peripheral drug administration on surgical wound biochemistry. This methodology has been applied to healthy women undergoing elective cesarean delivery with spinal anesthesia. We have measured wound exudate and serum mediators at the same time intervals as patient's pain scores and analgesics consumption for up to 48 hours post-cesarean delivery. Using this methodology we have been able to detect various biochemical mediators including nerve growth factor (NGF), prostaglandin E2 (PG-E2) substance P, IL-1β, IL-2, IL-4, IL-6, IL-7, IL-8, IL-10, IL-12, IL-13, IL-17, TNFα, INFγ, G-CSF, GM-CSF, MCP-1 and MIP-1β. Studies applying this human surgical wound bioassay have found no correlations between wound and serum cytokine concentrations or their time-release profile (J Pain. 2008; 9(7):650-7).(1) We also documented the utility of the technique to identify drug-mediated changes in wound cytokine content.

    View details for DOI 10.3791/50133

    View details for PubMedID 23117346

  • Necessity and Risks of Arterial Blood Sampling in Healthy Volunteer Studies CLINICAL PHARMACOKINETICS Oertel, B. G., Vermehren, J., Zimmermann, M., Huynh, T. T., Doehring, A., Ferreiros, N., Senzel, S., Schmitz-Rixen, T., Erbe, M., Geisslinger, G., Harder, S., Angst, M. S., Loetsch, J. 2012; 51 (10): 629-638


    Arterial blood sampling is necessary when drugs such as the fast-acting opioid analgesic remifentanil exhibit relevant differences between arterial and venous blood concentrations. Arterial cannulation is generally considered to be clinically safe and has thus become a standard procedure in pharmacokinetic-pharmacodynamic assessments. However, rare cases of arterial occlusions have to be considered in risk-benefit assessments of arterial sampling in pharmacokinetic studies, especially when including healthy volunteers. In an actual case, arterial occlusion requiring surgical repair was caused by a factor V Leiden thrombophilia associated genetic variant F5 1691G>A (rs6025) and aggravated by a hypoplastic radial artery. Neither risk factor had been identified prior to enrolment by routine laboratory tests such as the prothrombin time (international normalized ratio), partial thromboplastin time and the clinical Allen's test of arterial function. Re-assessment of the necessity of arterial sampling showed that none of the potential alternatives, target concentrations of computerized infusions or venous concentrations during non-steady-state and steady-state conditions could provide the arterial concentrations. Relying on venous concentrations may result in erroneous pharmacodynamic parameters. Accurate pharmacokinetic-pharmacodynamic studies relying on precisely measured blood concentrations require serial sampling techniques during both steady-state and non-steady-state conditions. However, as illustrated by the presented case, incidents involving the generally safe procedure of arterial sampling are possible, although rare. To further minimize the risks, screening of subjects for prothrombotic risks and careful assessment of the suitability of the artery should be considered in pharmacokinetic studies requiring arterial cannulation.

    View details for DOI 10.1007/s40262-012-0001-1

    View details for Web of Science ID 000309248300001

    View details for PubMedID 23018527

  • Selective nociceptor activation in volunteers by infrared diode laser MOLECULAR PAIN Tzabazis, A. Z., Klukinov, M., Crottaz-Herbette, S., Nemenov, M. I., Angst, M. S., Yeomans, D. C. 2011; 7


    Two main classes of peripheral sensory neurons contribute to thermal pain sensitivity: the unmyelinated C fibers and thinly myelinated Aδ fibers. These two fiber types may differentially underlie different clinical pain states and distinctions in the efficacy of analgesic treatments. Methods of differentially testing C and Aδ thermal pain are widely used in animal experimentation, but these methods are not optimal for human volunteer and patient use. Thus, this project aimed to provide psychophysical and electrophysiological evidence that whether different protocols of infrared diode laser stimulation, which allows for direct activation of nociceptive terminals deep in the skin, could differentially activate Aδ or C fiber thermonociceptors in volunteers.Short (60 ms), high intensity laser pulses (SP) evoked monomodal "pricking" pain which was not enhanced by topical capsaicin, whereas longer, lower power pulses (LP) evoked monomodal "burning" pain which was enhanced by topical capsaicin. SP also produced cortical evoked EEG potentials consistent with Aδ mediation, the amplitude of which was directly correlated with pain intensity but was not affected by topical capsaicin. LP also produced a distinct evoked potential pattern the amplitude of which was also correlated with pain intensity, which was enhanced by topical capsaicin, and the latency of which could be used to estimate the conduction velocity of the mediating nociceptive fibers.Psychophysical and electrophysiological data were consistent with the ability of short high intensity infrared laser pulses to selectively produce Aδ mediated pain and of longer pulses to selectively produce C fiber mediated thermal pain. Thus, the use of these or similar protocols may be useful in developing and testing novel therapeutics based on the differential molecular mechanisms underlying activation of the two fiber types (e.g., TRPV1, TRPV2, etc). In addition, these protocol may be useful in determining the fiber mediation of different clinical pain types which may, in turn be useful in treatment choice.

    View details for DOI 10.1186/1744-8069-7-18

    View details for Web of Science ID 000289115700001

    View details for PubMedID 21426575

    View details for PubMedCentralID PMC3070669

  • The Endogenous Opioid System Is Not Involved in Modulation of Opioid-Induced Hyperalgesia JOURNAL OF PAIN Chu, L. F., Dairmont, J., Zamora, A. K., Young, C. A., Angst, M. S. 2011; 12 (1): 108-115


    Some recent studies suggested a role of the endogenous opioid system in modulating opioid-induced hyperalgesia (OIH). In order to test this hypothesis, we conducted a prospective randomized, placebo-controlled, 2-way crossover study in healthy human volunteers. We utilized a well-established model of inducing OIH after a brief exposure to the μ-opioid agonist remifentanil using intradermal electrical stimulation. Patients were exposed to a randomized 90-minute infusion of remifentanil or saline placebo during 2 separate occasions. Development of OIH was quantified using changes in the average radius of the area of secondary hyperalgesia generated by electrical pain stimulation. A 23.6% (20.2) increase in area of secondary hyperalgesia over baseline was observed in the postinfusion period of the remifentanil session, demonstrating development of OIH (P = .03). In order to test endogenous opioid system modulation of OIH, patients were given a 1-time bolus of naloxone, which had no effect on the size of the hyperalgesic lesion in either the remifentinal or placebo session. These results suggested that the endogenous opioid system did not appear to modulate OIH.Experimental evidence suggested that the endogenous opioid system did not significantly affect opioid-induced hyperalgesia. Consequently, this study suggested that alternative mechanisms such as pronociceptive stimulation and neuroplastic changes might be responsible for expression of OIH.

    View details for DOI 10.1016/j.jpain.2010.05.006

    View details for PubMedID 20864417

  • The Role of Interleukin-1 in Wound Biology. Part I: Murine In Silico and In Vitro Experimental Analysis ANESTHESIA AND ANALGESIA Hu, Y., Liang, D., Li, X., Liu, H., Zhang, X., Zheng, M., Dill, D., Shi, X., Qiao, Y., Yeomans, D., Carvalho, B., Angst, M. S., Clark, J. D., Peltz, G. 2010; 111 (6): 1525-1533


    Wound healing is a multistep, complex process that involves the coordinated action of multiple cell types. Conflicting results have been obtained when conventional methods have been used to study wound biology. Therefore, we analyzed the wound response in a mouse genetic model.We analyzed inflammatory mediators produced within incisional wounds induced in 16 inbred mouse strains. Computational haplotype-based genetic analysis of inter-strain differences in the level of production of 2 chemokines in wounds was performed. An in vitro experimental analysis system was developed to investigate whether interleukin (IL)-1 could affect chemokine production by 2 different types of cells that are present within wounds.The level of 2 chemokines, keratinocyte-derived chemokine (KC) and macrophage inflammatory protein 1α, exhibited very large (75- and 463-fold, respectively) interstrain differences within wound tissue across this inbred strain panel. Genetic variation within Nalp1, an inflammasome component that regulates IL-1 production, correlated with the interstrain differences in KC and macrophage inhibitory protein 1α production. Consistent with the genetic correlation, IL-1β was shown to stimulate KC production by murine keratinocyte and fibroblast cell lines in vitro.Genetic variation within Nalp1 could contribute to interstrain differences in wound chemokine production by altering the amount of IL-1 produced.

    View details for DOI 10.1213/ANE.0b013e3181f5ef5a

    View details for PubMedID 20889942

  • Continuous Subcutaneous Instillation of Bupivacaine Compared to Saline Reduces Interleukin 10 and Increases Substance P in Surgical Wounds After Cesarean Delivery ANESTHESIA AND ANALGESIA Carvalho, B., Clark, D. J., Yeomans, D. C., Angst, M. S. 2010; 111 (6): 1452-1459


    Recent evidence suggests that locally delivered local anesthetics may exert tissue-damaging effects such as chondrolysis after intraarticular injection. Alteration of the inflammatory response is a potential mechanism for local anesthetic-induced tissue toxicity. In this study, we tested the effects of continuous local anesthetic infiltration on the release of inflammatory and nociceptive mediators in skin wounds after cesarean delivery.Thirty-eight healthy women undergoing cesarean delivery with spinal anesthesia were enrolled in this study, and were randomized to receive subcutaneous surgical wound infiltration with bupivacaine 5 mg/mL or saline at 2 mL/h for 24 hours after cesarean delivery. Wound exudate was sampled at 1, 3, 5, 7, and 24 hours after cesarean delivery using a subcutaneous wound drain technique. Cytokines, chemokines, substance P, prostaglandin E(2), and nerve growth factor were assayed using multiplex Bio-Plex® (Bio-Rad, Hercules, CA) and enzyme-linked immunosorbent assays.Bupivacaine wound infusion resulted in a significant decrease of interleukin 10 and increase of substance P in wounds compared with saline infusion (area under the 24-hour concentration-time curve; P < 0.001). No statistically significant differences were detected for other cytokines, nerve growth factor, and prostaglandin E(2).This study demonstrates that the continuous administration of clinically used doses of bupivacaine into wounds affects the local composition of wound mediators. Observed changes in interleukin 10 are compatible with a disruption of antiinflammatory mechanisms. Whether such modulation combined with the release of the proinflammatory mediator substance P results in an overall proinflammatory wound response will require future studies of wound healing.

    View details for DOI 10.1213/ANE.0b013e3181f579de

    View details for PubMedID 20861424

  • The Role of Interleukin-1 in Wound Biology. Part II: In Vivo and Human Translational Studies ANESTHESIA AND ANALGESIA Hu, Y., Liang, D., Li, X., Liu, H., Zhang, X., Zheng, M., Dill, D., Shi, X., Qiao, Y., Yeomans, D., Carvalho, B., Angst, M. S., Clark, J. D., Peltz, G. 2010; 111 (6): 1534-1542


    In the accompanying paper, we demonstrate that genetic variation within Nalp1 could contribute to interstrain differences in wound chemokine production through altering the amount of interleukin (IL)-1 produced. We further investigate the role of IL-1 in incisional wound biology and its effect on wound chemokine production in vivo and whether this mechanism could be active in human subjects.A well-characterized murine model of incisional wounding was used to assess the in vivo role of IL-1 in wound biology. The amount of 7 different cytokines/chemokines produced within an experimentally induced skin incision on a mouse paw and the nociceptive response was analyzed in mice treated with an IL-1 inhibitor. We also investigated whether human IL-1β or IL-1α stimulated the production of chemokines by primary human keratinocytes in vitro, and whether there was a correlation between IL-1β and chemokine levels in 2 experimental human wound paradigms.Administration of an IL-1 receptor antagonist to mice decreased the nociceptive response to an incisional wound, and reduced the production of multiple inflammatory mediators, including keratinocyte-derived chemokine (KC) and macrophage inhibitory protein (MIP)-1α, within the wounds. IL-1α and IL-1β stimulated IL-8 and GRO-α (human homologues of murine keratinocyte-derived chemokine) production by primary human keratinocytes in vitro. IL-1β levels were highly correlated with IL-8 in human surgical wounds, and at cutaneous sites of human ultraviolet B-induced sunburn injury.IL-1 plays a major role in regulating inflammatory mediator production in wounds through a novel mechanism; by stimulating the production of multiple cytokines and chemokines, it impacts clinically important aspects of wound biology. These data suggest that administration of an IL-1 receptor antagonist within the perioperative period could decrease postsurgical wound pain.

    View details for DOI 10.1213/ANE.0b013e3181f691eb

    View details for PubMedID 20889944

  • Effect of a Preemptive Femoral Nerve Block on Cytokine Release and Hyperalgesia in Experimentally Inflamed Skin of Human Volunteers REGIONAL ANESTHESIA AND PAIN MEDICINE Carvalho, B., Aleshi, P., Horstman, D. J., Angst, M. S. 2010; 35 (6): 514-519


    Tissue injury is associated with the local release of inflammatory and nociceptive mediators and the development of hyperalgesia. It is unclear whether interrupting neuronal signaling using regional anesthetic techniques at the time of the injury modifies local nociceptive and inflammatory processes. The aim of this study was to determine whether a peripheral nerve block at the time of tissue injury could modify the development of wound hyperalgesia and the local release of inflammatory and nociceptive mediators.Twelve healthy volunteers participated in this controlled, crossover, randomized study. A femoral nerve block or a sham block was established before inducing an experimental UVB burn on the thigh. Twenty-four hours later, the interstitial wound fluid was sampled, and mechanical and heat pain thresholds were assessed. Wound fluid concentrations of an array of cytokines, chemokines, nerve growth factor, prostaglandin E2, and substance P were determined.Skin inflammation was associated with the release of inflammatory and nociceptive mediators and resulted in significant tissue hyperalgesia (P < 0.001). However, the presence of a fully established peripheral nerve block at the time of tissue injury did not alter the development of hyperalgesia after regression of the block. Similarly, the presence of a peripheral nerve block did not modify the release of inflammatory or nociceptive mediators.These findings suggest that a preemptive, single-shot peripheral nerve block minimally affects wound hyperalgesia and inflammation. Continuous nerve block techniques may be better suited to alter nociceptive and inflammatory events in wounds beyond the duration of the block.

    View details for DOI 10.1097/AAP.0b013e3181faa107

    View details for PubMedID 20975465

  • The Analgesic and Antihyperalgesic Effects of Transcranial Electrostimulation with Combined Direct and Alternating Current in Healthy Volunteers ANESTHESIA AND ANALGESIA Nekhendzy, V., Lemmens, H. J., Tingle, M., Nekhendzy, M., Angst, M. S. 2010; 111 (5): 1301-1307


    Transcranial electrostimulation (TES) has been reported to produce clinically significant analgesia, but randomized and double-blind studies are lacking. We investigated the analgesic and antihyperalgesic effects of TES in validated human experimental pain models.In 20 healthy male subjects we evaluated the analgesic and antihyperalgesic effects of TES(60Hz) and TES(100Hz) to heat and mechanical pain in experimentally induced ultraviolet B skin sunburns and in normal skin. Previous animal studies in our laboratory predicted that TES(60Hz) would provide significant analgesia, and TES(100Hz) was a suitable active control. The study was conducted in a double-blind, randomized, 2-way cross-over fashion. TES was administered for 35 minutes. Quantitative sensory testing evaluating heat and mechanical pain thresholds was conducted before TES, during TES, and 45 minutes after TES.TES (TES(60Hz) > TES(100Hz)) evoked rapidly developing, significant thermal and mechanical antihyperalgesic effects in the ultraviolet B lesion, and attenuated thermal pain in unimpaired skin. No long-lasting analgesic and antihyperalgesic effects of a single TES treatment were demonstrated in this study.TES produces significant, frequency-dependent antihyperalgesic and analgesic effects in humans. The characteristics of the TES effects indicate a high likelihood of its ability to modulate both peripheral sensitization of nociceptors and central hyperexcitability.

    View details for DOI 10.1213/ANE.0b013e3181e3697e

    View details for PubMedID 20530614

  • Opioid Pharmacogenomics Using a Twin Study Paradigm: Methods and Procedures for Determining Familial Aggregation and Heritability TWIN RESEARCH AND HUMAN GENETICS Angst, M. S., Phillips, N. G., Drover, D. R., Tingle, M., Galinkin, J. L., Christians, U., Swan, G. E., Lazzeroni, L. C., Clark, J. D. 2010; 13 (5): 412-425


    Opioids are the cornerstone medication for the treatment of moderate to severe pain. However, analgesic opioid requirements and the propensity to suffer from aversive opioid effects, including fatal respiratory depression and addiction, vary widely among patients. The factors underlying the substantial response variance remain largely unknown and need clarification for using opioids more effectively in appropriately selected patients. This ongoing study takes advantage of the twin paradigm to estimate the genetic and environmental contributions to inter-individual differences in opioid responses. Evidence of significant heritability will justify more detailed and extensive genomic studies. The enrollment target is 80 monozygotic and 45 dizygotic twin pairs who undergo a target-controlled infusion of the opioid alfentanil and saline placebo in sequential but randomized order. In a laboratory-type setting, well-defined pharmacodynamic endpoints are measured to quantify pain sensitivity, analgesic opioid effects, and aversive opioid effects including respiratory depression, sedation and reinforcing affective responses. First results obtained in 159 participants provide evidence for the feasibility and utility of this interventional study paradigm to estimate familial aggregation and heritability components of relevant drug effects. Areas highlighted in this report include recruitment strategies, required infrastructure and personnel, selection of relevant outcome measures, drug infusion algorithm minimizing pharmacokinetic variability, and considerations for optimizing data quality and quantity without hampering feasibility. Applying the twin paradigm to complex and potentially harmful studies comprehensively characterizing pharmacological response profiles is without much precedent. Methods and first results including heritability estimates for heat and cold pain sensitivity should be of interest to investigators considering similar studies.

    View details for PubMedID 20874462

  • Opioid Pharmacotherapy for Chronic Non-Cancer Pain in the United States: A Research Guideline for Developing an Evidence-Base JOURNAL OF PAIN Chapman, C. R., Lipschitz, D. L., Angst, M. S., Chou, R., Denisco, R. C., Donaldson, G. W., Fine, P. G., Foley, K. M., Gallagher, R. M., Gilson, A. M., Haddox, J. D., Horn, S. D., Inturrisi, C. E., Jick, S. S., Lipman, A. G., Loeser, J. D., Noble, M., Porter, L., Rowbotham, M. C., Schoelles, K. M., Turk, D. C., Volinn, E., Von Korff, M. R., Webster, L. R., Weisner, C. M. 2010; 11 (9): 807-829


    This document reports the consensus of an interdisciplinary panel of research and clinical experts charged with reviewing the use of opioids for chronic noncancer pain (CNCP) and formulating guidelines for future research. Prescribing opioids for chronic noncancer pain has recently escalated in the United States. Contrasting with increasing opioid use are: 1) The lack of evidence supporting long-term effectiveness; 2) Escalating misuse of prescription opioids including abuse and diversion; and 3) Uncertainty about the incidence and clinical salience of multiple, poorly characterized adverse drug events (ADEs) including endocrine dysfunction, immunosuppression and infectious disease, opioid-induced hyperalgesia and xerostomia, overdose, falls and fractures, and psychosocial complications. Chief among the limitations of current evidence are: 1) Sparse evidence on long-term opioid effectiveness in chronic pain patients due to the short-term time frame of clinical trials; 2) Insufficiently comprehensive outcome assessment; and 3) Incomplete identification and quantification of ADEs. The panel called for a strategic interdisciplinary approach to the problem domain in which basic scientists and clinicians cooperate to resolve urgent issues and generate a comprehensive evidence base. It offered 4 recommendations in 3 areas: 1) A research strategy for studying the effectiveness of long-term opioid pharmacotherapy; 2) Improvements in evidence-generation methodology; and 3) Potential research topics for generating new evidence.Prescribing opioids for CNCP has outpaced the growth of scientific evidence bearing on the benefits and harms of these interventions. The need for a strong evidence base is urgent. This guideline offers a strategic approach to creating a comprehensive evidence base to guide safe and effective management of CNCP.

    View details for DOI 10.1016/j.jpain.2010.02.019

    View details for Web of Science ID 000282033900001

    View details for PubMedID 20430701

  • Ketamine for Managing Perioperative Pain in Opioid-dependent Patients with Chronic Pain A Unique Indication? ANESTHESIOLOGY Angst, M. S., Clark, J. D. 2010; 113 (3): 514-515

    View details for DOI 10.1097/ALN.0b013e3181e9092d

    View details for Web of Science ID 000281251600004

    View details for PubMedID 20683248

  • Perioperative Hypothermia (33 degrees C) Does Not Increase the Occurrence of Cardiovascular Events in Patients Undergoing Cerebral Aneurysm Surgery Findings from the Intraoperative Hypothermia for Aneurysm Surgery Trial ANESTHESIOLOGY Nguyen, H. P., Zaroff, J. G., Bayman, E. O., Gelb, A. W., Todd, M. M., Hindman, B. J. 2010; 113 (2): 327-342


    Perioperative hypothermia has been reported to increase the occurrence of cardiovascular complications. By increasing the activity of sympathetic nervous system, perioperative hypothermia also has the potential to increase cardiac injury and dysfunction associated with subarachnoid hemorrhage.The Intraoperative Hypothermia for Aneurysm Surgery Trial randomized patients undergoing cerebral aneurysm surgery to intraoperative hypothermia (n = 499, 33.3 degrees +/- 0.8 degrees C) or normothermia (n = 501, 36.7 degrees +/- 0.5 degrees C). Cardiovascular events (hypotension, arrhythmias, vasopressor use, myocardial infarction, and others) were prospectively followed until 3-month follow-up and were compared in hypothermic and normothermic patients. A subset of 62 patients (hypothermia, n = 33; normothermia, n = 29) also had preoperative and postoperative (within 24 h) measurement of cardiac troponin-I and echocardiography to explore the association between perioperative hypothermia and subarachnoid hemorrhage-associated myocardial injury and left ventricular function.There was no difference between hypothermic and normothermic patients in the occurrence of any single cardiovascular event or in composite cardiovascular events. There was no difference in mortality (6%) between groups, and there was only a single primary cardiovascular death (normothermia). There was no difference between hypothermic and normothermic patients in postoperative versus preoperative left ventricular regional wall motion or ejection fraction. Compared with preoperative values, hypothermic patients had no postoperative increase in cardiac troponin-I (median change 0.00 microg/l), whereas normothermic patients had a small postoperative increase (median change + 0.01 microg/l, P = 0.038).In patients undergoing cerebral aneurysm surgery, perioperative hypothermia was not associated with an increased occurrence of cardiovascular events.

    View details for DOI 10.1097/ALN.0b013e3181dfd4f7

    View details for Web of Science ID 000280363900011

    View details for PubMedID 20571361

  • Identification of a complex between fibronectin and aggrecan G3 domain in synovial fluid of patients with painful meniscal pathology CLINICAL BIOCHEMISTRY Scuderi, G. J., Woolf, N., Dent, K., Golish, S. R., Cuellar, J. M., Cuellar, V. G., Yeomans, D. C., Carragee, E. J., Angst, M. S., Bowser, R., Hanna, L. S. 2010; 43 (10-11): 808-814


    We previously described a panel of four cytokines biomarkers in knee synovial fluid for acute knee pain associated with meniscal pathology. The cytokine biomarkers included interferon gamma (IFN-gamma), interleukin 6 (IL-6), monocyte chemotactic protein 1 (MCP-1), and macrophage inflammatory protein-1 beta (MIP-1beta). Validation studies using other immunologic techniques confirmed the presence of IL-6, MCP-1 and MIP-1beta, but not IFN-gamma. Therefore we sought the identity of the IFN-gamma signal in synovial fluid.Knee synovial fluid was collected from patients with an acute, painful meniscal injury, as well as asymptomatic volunteers. A combination of high-pressure chromatography, mass spectrometry and immunological techniques were used to enrich and identify the protein components representing the IFN-gamma signal.A protein complex of fibronectin and the aggrecan G3 domain was identified in the synovial fluid of patients with a meniscal tear and pain that was absent in asymptomatic controls. This protein complex correlated to the IFN-gamma signal. A novel enzyme-linked immunosorbent assay (ELISA) was developed to specifically identify the complex in synovial fluid.We have identified a protein complex of fibronectin and aggrecan G3 domain that is a candidate biomarker for pain associated with meniscal injury.

    View details for DOI 10.1016/j.clinbiochem.2010.04.069

    View details for PubMedID 20460120

  • Intrathecal Cyclooxygenase Inhibitors in Humans Don't Throw in the Towel! ANESTHESIOLOGY Angst, M. S. 2010; 112 (5): 1082-1083

    View details for DOI 10.1097/ALN.0b013e3181d94e41

    View details for Web of Science ID 000277284800010

    View details for PubMedID 20418688

  • Cytokine evaluation in individuals with low back pain using discographic lavage SPINE JOURNAL Cuellar, J. M., Golish, S. R., Reuter, M. W., Cuellar, V. G., Angst, M. S., Carragee, E. J., Yeomans, D. C., Scuderi, G. J. 2010; 10 (3): 212-218


    The pathophysiology underlying degenerative disc disease and its implication in painful syndromes remain unclear. However, spine magnetic resonance imaging (MRI) can demonstrate changes in disc water content and the annulus; provocative discography purportedly identifies degenerate discs causing serious low back pain; and biochemical assays have identified local inflammatory markers. No study to date has correlated pain on disc injection during discography evaluation with relevant MRI findings and biochemical markers.The purpose of this study was to correlate concordant pain on during discography to biochemical markers obtained by disc lavage and MRI findings.This is a Phase 1 Diagnostic Test Assessment Cohort Study (Sackett and Haynes).The patient sample included 21 symptomatic patients with suspected discogenic pain and three Phase 1 control subjects.The outcome measures included discography pain scores, MRI degenerative grades, and immunoreactivity to various inflammatory cytokine concentrations present in disc lavage samples.Twenty-one symptomatic patients with lumbar degenerative disc disease and three control subjects underwent discography, MRI, and biochemical analysis of disc lavage fluid. Lumbar MRI was scored for Pfirrmann grading of the lumbar discs, and annular disruption was identified by nuclear disc lavage. Disc lavage samples were analyzed for biochemical markers by high-sensitivity immunoassay.Eighty-three discs from 24 patients were studied: 67 discs from 21 patients with axial back pain (suspected discogenic pain group) and 16 discs from 3 scoliosis patients without back pain (Phase 1 control subjects). Among the biochemical markers surveyed, interferon gamma (IFN-gamma) immunoreactivity was most consistently identified in patients with axial back pain. Discs with annular disruption and concordant pain reproduction at a visual analog scale of 7 to 10/10 had greater IFN-gamma immunoreactivity than those without this finding (p=.003); however, at least some IFN-gamma immunoreactivity was found in all but one disc in the symptomatic group.Among the potential inflammatory markers tested in this Phase 1 study, IFN-gamma immunoreactivity was most commonly elevated in discogram "positive" discs but absent in asymptomatic controls. However, this marker was also frequently elevated in degenerative but "negative" discography discs. From these findings, Phase 2 and Phase 3 validity studies are reasonable to pursue. Phase 4 utility studies may be performed concurrently to assess this method's predictive value in outcome studies.

    View details for DOI 10.1016/j.spinee.2009.12.007

    View details for Web of Science ID 000208284600006

    View details for PubMedID 20207331

  • Selective Antagonism of Opioid-Induced Ventilatory Depression by an Ampakine Molecule in Humans Without Loss of Opioid Analgesia CLINICAL PHARMACOLOGY & THERAPEUTICS Oertel, B. G., Felden, L., Tran, P. V., Bradshaw, M. H., Angst, M. S., Schmidt, H., JOHNSON, S., Greer, J. J., Geisslinger, G., Varney, M. A., Loetsch, J. 2010; 87 (2): 204-211


    Ventilatory depression is a significant risk associated with the use of opioids. We assessed whether opioid-induced ventilatory depression can be selectively antagonized by an ampakine without reduction of analgesia. In 16 healthy men, after a single oral dose of 1,500 mg of the ampakine CX717, a target concentration of 100 ng/ml alfentanil decreased the respiratory frequency by only 2.9 +/- 33.4% as compared with 25.6 +/- 27.9% during placebo coadministration (P < 0.01).Blood oxygenation and the ventilatory response to hypercapnic challenge also showed significantly smaller decreases with CX717 than with placebo. In contrast, CX717 did not affect alfentanil-induced analgesia in either electrical or heat-based experimental models of pain. Both ventilatory depression and analgesia were reversed with 1.6 mg of naloxone. These results support the use of ampakines as selective antidotes in humans to counter opioid-induced ventilatory depression without affecting opioid-mediated analgesia.

    View details for DOI 10.1038/clpt.2009.194

    View details for Web of Science ID 000274140200018

    View details for PubMedID 19907420

  • No Association between Intraoperative Hypothermia or Supplemental Protective Drug and Neurologic Outcomes in Patients Undergoing Temporary Clipping during Cerebral Aneurysm Surgery Findings from the Intraoperative Hypothermia for Aneurysm Surgery Trial ANESTHESIOLOGY Hindman, B. J., Bayman, E. O., Pfisterer, W. K., Torner, J. C., Todd, M. M. 2010; 112 (1): 86-101


    Although hypothermia and barbiturates improve neurologic outcomes in animal temporary focal ischemia models, the clinical efficacy of these interventions during temporary occlusion of the cerebral vasculature during intracranial aneurysm surgery (temporary clipping) is not established.A post hoc analysis of patients from the Intraoperative Hypothermia for Aneurysm Surgery Trial who underwent temporary clipping was performed. Univariate and multivariate logistic regression methods were used to test for associations between hypothermia, supplemental protective drug, and short- (24-h) and long-term (3-month) neurologic outcomes. An odds ratio more than 1 denotes better outcome.Patients undergoing temporary clipping (n = 441) were assigned to intraoperative hypothermia (33.3 degrees +/- 0.8 degrees C, n = 208) or normothermia (36.7 degrees +/- 0.5 degrees C, n = 233), with 178 patients also receiving supplemental protective drug (thiopental or etomidate) during temporary clipping. Three months after surgery, 278 patients (63%) had good outcome (Glasgow Outcome Score = 1). Neither hypothermia (P = 0.847; odds ratio = 1.043, 95% CI = 0.678-1.606) nor supplemental protective drug (P = 0.835; odds ratio = 1.048, 95% CI = 0.674-1.631) were associated with 3-month Glasgow Outcome Score. The effect of supplemental protective drug did not significantly vary with temperature. The effects of hypothermia and protective drug did not significantly vary with temporary clip duration. Similar findings were made for 24-h neurologic status and 3-month Neuropsychological Composite Score.In the Intraoperative Hypothermia for Aneurysm Surgery Trial, neither systemic hypothermia nor supplemental protective drug affected short- or long-term neurologic outcomes of patients undergoing temporary clipping.

    View details for Web of Science ID 000273314200016

    View details for PubMedID 19952722

  • Epidural Interferon Gamma-Immunoreactivity A Biomarker for Lumbar Nerve Root Irritation SPINE Scuderi, G. J., Cuellar, J. M., Cuellar, V. G., Yeomans, D. C., Carragee, E. J., Angst, M. S. 2009; 34 (21): 2311-2317


    Prospective observational cohort.Correlate epidural inflammatory cytokines with the clinical response to epidural steroid injection in patients with lumbar nerve root irritation.Some back pain syndromes are thought to be associated with activation of inflammatory pathways and others may be associated with primary mechanical derangements. Human studies providing detailed evidence for the primary inflammatory causation, which may be best treated with anti-inflammatory strategies, are lacking. There are currently no accurate diagnostic tests to predict the response to epidural steroid injection or surgical intervention in back pain and sciatica syndromes. METHODS.: Forty-seven consecutive patients with lumbar degenerative changes and low back and/or leg pain were prospectively enrolled. An epidural lavage was performed, followed by injection of marcaine/depo-medrol. Subjects scored their pain before and 3 months after the procedure. The immunoreactivity of an array of cytokines was measured in lavage samples and compared with clinical response to the therapeutic injection. Ten subjects underwent repeat epidural lavage sampling 3 months after the steroid injection.Interferon gamma (IFNgamma) was the most consistently detected cytokine. IFNgamma-immunoreactivity also highly correlated with reported reduction of pain 3-months after the epidural steroid injection. In subjects reporting significant pain relief (>50%) from the injection, mean [IFNgamma] was significantly greater compared with patients experiencing no significant relief. The IFNgamma-immunoreactivity in repeat lavage samples decreased to trace residual concentrations in patients who reported pain relief from the steroid injection.The presence of epidural IFNgamma-immunoreactivity corresponding to >10 pg/mL predicted significant pain relief after epidural steroid injection with >95% accuracy. These results suggest that IFNgamma may be part of a biochemical cascade triggering pain in sciatica; IFNgamma-immunoreactivity may aid as a biomarker for predicting the response to steroid therapy and/or surgical intervention, and may serve as a future therapeutic target.

    View details for DOI 10.1097/BRS.0b013e3181af06b6

    View details for Web of Science ID 000270382600011

    View details for PubMedID 19934811

  • PERIOPERATIVE FEVER AND OUTCOME IN SURGICAL PATIENTS WITH ANEURYSMAL SUBARACHNOID HEMORRHAGE NEUROSURGERY Todd, M. M., Hindman, B. J., Clarke, W. R., Torner, J. C., Weeks, J. B., Bayman, E. O., Shi, Q., Spofford, C. M. 2009; 64 (5): 897-908


    We examined the incidence of perioperative fever and its relationship to outcome among patients enrolled in the Intraoperative Hypothermia for Aneurysm Surgery Trial.One thousand patients with initial World Federation of Neurological Surgeons grades of I to III undergoing clipping of intracranial aneurysms after subarachnoid hemorrhage were randomized to intraoperative normothermia (36 degrees C-37 degrees C) or hypothermia (32.5 degrees C-33.5 degrees C). Fever (> or =38.5 degrees C) and other complications (including infections) occurring between admission and discharge (or death) were recorded. Functional and neuropsychologic outcomes were assessed 3 months postoperatively. The primary outcome variable for the trial was dichotomized Glasgow Outcome Scale (good outcome versus all others).Fever was reported in 41% of patients. In 97% of these, fever occurred in the postoperative period. The median time from surgery to first fever was 3 days. All measures of outcome were worse in patients who developed fever, even in those without infections or who were World Federation of Neurological Surgeons grade I. Logistic regression analyses were performed to adjust for differences in preoperative factors (e.g., age, Fisher grade, initial neurological status). This demonstrated that fever continued to be significantly associated with most outcome measures, even when infection was added to the model. An alternative stepwise model selection process including all fever-related measures from the preoperative and intraoperative period (e.g., hydrocephalus, duration of surgery, intraoperative blood loss) resulted in the loss of significance for dichotomized Glasgow Outcome Scale, but significant associations between fever and several other outcome measures remained. After adding postoperative delayed ischemic neurological deficits to the model, only worsened National Institutes of Health Stroke Scale score, Barthel Activities of Daily Living index, and discharge destination (home versus other) remained independently associated with fever.These findings suggest that fever is associated with worsened outcome in surgical subarachnoid hemorrhage patients, although, because the association between fever and the primary outcome measure for the trial is dependent on the covariates used in the analysis (particularly operative events and delayed ischemic neurological deficits), we cannot rule out the possibility that fever is a marker for other events. Only a formal trial of fever treatment or prevention can address this issue.

    View details for DOI 10.1227/01.NEU.0000341903.11527.2F

    View details for Web of Science ID 000265661100034

    View details for PubMedID 19404150

  • No evidence for the development of acute tolerance to analgesic, respiratory depressant and sedative opioid effects in humans PAIN Angst, M. S., Chu, L. F., Tingle, M. S., Shafer, S. L., Clark, J. D., Drover, D. R. 2009; 142 (1-2): 17-26


    It is widely accepted that chronic opioid therapy is associated with the development of pharmacological tolerance. More controversial is the question as to whether acute opioid administration can result in "acute tolerance." The aim of this double-blind, placebo-controlled study in thirty-six healthy human volunteers was to examine whether a 3-h intravenous infusion delivering two different but clinically relevant doses of the mu-opioid receptor agonist remifentanil would result in tolerance to analgesic, respiratory depressant and/or sedative opioid effects. The blood remifentanil concentration versus opioid effect relationship was determined before and after the 3-h infusion. Tolerance was inferred if the potency of remifentanil was significantly lower after the 3-h infusion. Opioid analgesia was assessed with the aid of the cold pressor test and models of electrical and heat pain. Respiratory depression was assessed by measuring arterial pCO2 and minute ventilation. Subjective sedation scores were assessed on a visual analogue scale. Mixed effects modeling was used to relate the steady-state blood remifentanil concentration to each pharmacodynamic assessment. Neither dose of remifentanil produced detectable tolerance to any of the measured opioid effects following a 3-h infusion. The study was adequately powered to detect a decrease in potency of 5-24% for analgesia, 20-48% for respiratory depression, and 32% for sedative effects. These results suggest that short-term administration of clinically useful doses of remifentanil is not associated with the development of significant tolerance to analgesic, respiratory depressant, or sedative opioid effects.

    View details for DOI 10.1016/j.pain.2008.11.001

    View details for PubMedID 19135798

  • Effect of Nitrous Oxide Use on Long-term Neurologic and Neuropsychological Outcome in Patients Who Received Temporary Proximal Artery Occlusion during Cerebral Aneurysm Clipping Surgery ANESTHESIOLOGY Pasternak, J. J., McGregor, D. G., Lanier, W. L., Schroeder, D. R., Rusy, D. A., Hindman, B., Clarke, W., Torner, J., Todd, M. M. 2009; 110 (3): 563-573


    The authors explored the relationship between nitrous oxide use and neurologic and neuropsychological outcome in a population of patients likely to experience intraoperative cerebral ischemia: those who had temporary cerebral arterial occlusion during aneurysm clipping surgery.A post hoc analysis of a subset of the data from the Intraoperative Hypothermia for Aneurysm Surgery Trial was conducted. Only subjects who had temporary arterial occlusion during surgery were included in the analysis. Metrics of short-term and long-term (i.e., 3 months after surgery) outcome were evaluated via both univariate and multivariate logistic regression analysis. An odds ratio (OR) greater than 1.0 denotes a worse outcome in patients receiving nitrous oxide.The authors evaluated 441 patients, of which 199 received nitrous oxide. Patients receiving nitrous oxide had a greater risk of delayed ischemic neurologic deficits (i.e., the clinical manifestation of vasospasm) (OR, 1.78, 95% confidence interval [CI], 1.08-2.95; P = 0.025). However, at 3 months after surgery, there was no difference in any metric of gross neurologic outcome: Glasgow Outcome Score (OR, 0.67; CI, 0.44-1.03; P = 0.065), Rankin Score (OR, 0.74; CI, 0.47-1.16; P = 0.192), National Institutes of Health Stroke Scale (OR, 1.02; CI, 0.66-1.56; P = 0.937), or Barthel Index (OR, 0.69; CI, 0.38-1.25; P = 0.22). The risk of impairment on at least one test of neuropsychological function was reduced in those who received nitrous oxide (OR, 0.56; CI, 0.36-0.89; P = 0.013).In this patient population, use of nitrous oxide was associated with an increased risk for the development of delayed ischemic neurologic deficits; however, there was no evidence of detriment to long-term gross neurologic or neuropsychological outcome.

    View details for Web of Science ID 000263734900018

    View details for PubMedID 19212259

    View details for PubMedCentralID PMC2735401

  • Determining heat and mechanical pain threshold in inflamed skin of human subjects. Journal of visualized experiments : JoVE Angst, M. S., Tingle, M., Phillips, N. G., Carvalho, B. 2009


    In a previous article in the Journal of Visualized Experiments we have demonstrated skin microdialysis techniques for the collection of tissue-specific nociceptive and inflammatory biochemicals in humans. In this article we will show pain-testing paradigms that are often used in tandem with microdialysis procedures. Combining pain tests with microdialysis provides the critical link between behavioral and biochemical data that allows identifying key biochemicals responsible for generating and propagating pain. Two models of evoking pain in inflamed skin of human study participants are shown. The first model evokes pain with aid of heat stimuli. Heat evoked pain as described here is predominantly mediated by small, non-myelinated peripheral nociceptive nerve fibers (C-fibers). The second model evokes pain via punctuated pressure stimuli. Punctuated pressure evoked pain is predominantly mediated by small, myelinated peripheral nociceptive nerve fibers (A-delta fibers). The two models are mechanistically distinct and independently examine nociceptive processing by the two major peripheral nerve fiber populations involved in pain signaling. Heat pain is evoked with aid of the TSA II, a commercially available thermo-sensory analyzer (Medoc Advanced Medical Systems, Durham, NC). Stimulus configuration and delivery is handled with aid of specific software. Thermodes vary in size and shape but in principle consist of a metal plate that can be heated or cooled at various rates and for different periods of time. Algorithms assessing heat-evoked pain are manifold. In the experiments shown here, study participants are asked to indicate at what point they start experiencing pain while the thermode in contact with skin is heated at a predetermined rate starting at a temperature that does not evoke pain. The thermode temperature at which a subject starts experiencing pain constitutes the heat pain threshold. Mechanical pain is evoked with punctuated probes. Such probes are commercially available from several manufacturers (von Frey hairs). However, the accuracy of von Frey hairs has been criticized and many investigators use custom made punctuated pressure probes. In the experiments shown here eight custom-made punctuated probes of different weights are applied in consecutive order, a procedure called up-down algorithm, to identify perceptional deflection points, i.e., a change from feeling no pain to feeling pain or vice versa. The average weight causing a perceptional deflection constitutes the mechanical pain threshold.

    View details for DOI 10.3791/1092

    View details for PubMedID 19229176

  • Molecular Basis and Clinical Implications of Opioid Tolerance and Opioid- Induced Hyperalgesia Acute Pain Management Chu, L. F., Clark, J., Angst, M. S. edited by Sinatra, R. S., deLeon-Casasola, O. A., Ginsberg, B., Viscusi, E. R. Cambridge University Press. 2009: 114–143
  • Peritoneal Surgery Anesthesiologist’s Manual of Surgical Procedures Norton, J. A., Oberhelmen, H. A., Angst, M. S. edited by Jaffe, R. A., Samuels, S. Lippincott Williams & Wilkins. 2009; 4: 625–644
  • Pancreatic Surgery Anesthesiologist’s Manual of Surgical Procedures Norton, J. A., Angst, M. S. edited by Jaffe, R. A., Samuels, S. Lippincott Williams & Wilkins. 2009; 4: 609–624
  • Overview on Clinical Features of Opioid-induced Hyperalgesia Opioid- induced Hyperalgesia Angst, M. S., Chu, L. F., Clark, J. edited by Mao, J. Informa Healthcare. 2009: 21–37
  • Cytokine profile in human skin in response to experimental inflammation, noxious stimulation, and administration of a COX-inhibitor: A microdialysis study PAIN Angst, M. S., Clark, J. D., Carvalho, B., Tingle, M., Schmelz, M., Yeomans, D. C. 2008; 139 (1): 15-27


    Animal studies have documented a critical role for cytokines in cell signaling events underlying inflammation and pain associated with tissue injury. While clinical reports indicate an important role of cytokines in inflammatory pain, methodological limitations have made systematic human studies difficult. This study examined the utility of a human in vivo bioassay combining microdialysis with multiplex immunoassay techniques for measuring cytokine arrays in tissue. The first experiment measured cytokines in interstitial fluid collected from non-inflamed and experimentally inflamed skin (UVB). The effects of noxious heat on cytokine release were also assessed. The second experiment examined whether anti-hyperalgesic effects of the COX-inhibitor ibuprofen were associated with decreased tissue levels of the pro-inflammatory cytokines IL-1 beta and IL-6. In the first experiment, inflammation significantly increased IL-1 beta, IL-6, IL-8, IL-10, G-CSF, and MIP-1 beta. Noxious heat but not experimental inflammation significantly increased IL-7 and IL-13. In the second experiment, an oral dose of 400 and 800 mg ibuprofen produced similar anti-hyperalgesic effects suggesting a ceiling effect. Tissue levels of IL-1 beta and IL-6 were not affected after the 400mg dose but decreased significantly (44+/-32% and 38+/-13%) after the 800 mg dose. These results support the utility of explored method for tracking cytokines in human tissue and suggest that anti-hyperalgesic and anti-inflammatory effects of ibuprofen are at least partially dissociated. The data further suggest that high clinical doses of ibuprofen exert anti-inflammatory effects by down-regulating tissue cytokine levels. Explored human bioassay is a promising tool for studying the pathology and pharmacology of inflammatory and chronic pain conditions.

    View details for DOI 10.1016/j.pain.2008.02.028

    View details for PubMedID 18396374

  • Opioid-induced pain - In reply JOURNAL OF CLINICAL ONCOLOGY Davis, M. P., Angst, M. 2008; 26 (20): 3465
  • Opioid-induced hyperalgesia in humans - Molecular mechanisms and clinical considerations CLINICAL JOURNAL OF PAIN Chu, L. F., Angst, M. S., Clark, D. 2008; 24 (6): 479-496


    Opioid-induced hyperalgesia (OIH) is most broadly defined as a state of nociceptive sensitization caused by exposure to opioids. The state is characterized by a paradoxical response whereby a patient receiving opioids for the treatment of pain may actually become more sensitive to certain painful stimuli. The type of pain experienced may or may not be different from the original underlying painful condition. Although the precise molecular mechanism is not yet understood, it is generally thought to result from neuroplastic changes in the peripheral and central nervous systems that lead to sensitization of pronociceptive pathways. OIH seems to be a distinct, definable, and characteristic phenomenon that may explain loss of opioid efficacy in some cases. Clinicians should suspect expression of OIH when opioid treatment effect seems to wane in the absence of disease progression, particularly if found in the context of unexplained pain reports or diffuse allodynia unassociated with the pain as previously observed. This review highlights the important mechanistic underpinnings and clinical ramifications of OIH and discusses future research directions and the latest clinical evidence for modulation of this potentially troublesome clinical phenomenon.

    View details for PubMedID 18574358

  • Local and systemic release of cytokines, nerve growth factor, prostaglandin E2, and substance P in incisional wounds and serum following cesarean delivery JOURNAL OF PAIN Carvalho, B., Clark, D. J., Angst, M. S. 2008; 9 (7): 650-657


    The objectives of this study were to test the feasibility of measuring inflammatory and nociceptive biochemical mediators at the surgical site and to evaluate the relationship between wound and serum levels as well as determine any associations between mediator release, pain, and analgesic consumption after cesarean delivery. Twenty healthy women undergoing elective cesarean delivery with spinal anesthesia were enrolled. Wound exudate and serum mediators, pain scores, and analgesic consumption were measured at 1, 6, 24, and 48 hours after cesarean. In wound exudate, 19 of 20 mediators were reliably detected including interleukin (IL)-1beta, IL-2, IL-4, IL-6, IL-7, IL-8, IL-10, IL-12, IL-13, IL-17, tumor necrosis factor-alpha, interferon-gamma, granulocyte colony stimulating factor (G-CSF), granulocyte-macrophage colony stimulating factor (GM-CSF), monocyte chemoattractant protein 1 (MCP-1) and macrophage inflammatory protein 1 (MIP-1beta), nerve growth factor (NGF), prostaglandin E2 (PG-E2), and substance P. Wound PG-E2 and various cytokines peaked early, whereas NGF showed a more delayed release. There were no correlations between the concentration versus time profile of wound and serum cytokines. Analgesic consumption during the first 24 hours after surgery was negatively correlated with IL-1beta, IL-6, and G-CSF in the wound exudate. This study demonstrates the feasibility of collecting and measuring nociceptive and inflammatory mediators in surgical wounds at specific time points. The lack of significant correlations between wound and serum levels emphasizes the importance of determining site-specific release if localized pathologies are to be studied.This study demonstrates the feasibility of measuring real-time nociceptive and inflammatory mediators in surgical wounds. Our findings confirm the lack of correlation between wound and serum levels of many pro-inflammatory and anti-inflammatory cytokines and nerve growth factor.

    View details for DOI 10.1016/j.jpain.2008.02.004

    View details for PubMedID 18394968

  • Opioid-nduced hyperalgesia may be more frequent than previously thought - Reply JOURNAL OF CLINICAL ONCOLOGY Davis, M. P., Angst, M. 2008; 26 (9): 1565
  • Chronic morphine administration enhances nociceptive sensitivity and local cytokine production after incision MOLECULAR PAIN Liang, D., Shi, X., Qiao, Y., Angst, M. S., Yeomans, D. C., Clark, J. D. 2008; 4


    The chronic use of opioids prior to surgery leads to lowered pain thresholds and exaggerated pain levels after these procedures. Several mechanisms have been proposed to explain this heightened sensitivity commonly termed opioid-induced hyperalgesia (OIH). Most of these proposed mechanisms involve plastic events in the central or peripheral nervous systems. Alterations in the abundance of peripheral mediators of nociception have not previously been explored.In these experiments mice were treated with saline (control) or ascending daily doses of morphine to generate a state of OIH followed by hind paw incision. In other experiments morphine treatment was initiated at the time of incision. Both mechanical allodynia and peri-incisional skin cytokine levels were measured. Myeloperoxidase (MPO) assays were used to determine neutrophil activity near the wounds. The cytokine production inhibitor pentoxifylline was used to determine the functional significance of the excess cytokines in previously morphine treated animals. Mice treated chronically treated with morphine prior to incision were found to have enhanced skin levels of IL-1beta, IL-6, G-CSF, KC and TNFalpha after incision at one or more time points compared to saline pretreated controls. The time courses of individual cytokines followed different patterns. There was no discernable effect of chronic morphine treatment on wound area neutrophil infiltration. Pentoxifylline reduced cytokine levels and reversed the excess mechanical sensitization caused by chronic morphine administration prior to incision. Morphine treatment initiated at the time of incision did not lead to a generalized enhancement of cytokine production or nociceptive sensitization in excess of the levels observed after incision alone.The enhanced level of nociceptive sensitization seen after incision in animals chronically exposed to morphine is associated with elevated levels of several cytokines previously reported to be relevant to this incisional pain model. The cytokines may be functional in supporting nociceptive sensitization because pentoxifylline reverses both peri-incisional skin cytokine levels and OIH. Opioid administration beginning at the time of incision does not seem to have the same cytokine enhancing effect. Approaches to postoperative pain control involving a reduction of cytokines may be an effective way to control excessive pain in patients chronically using opioids prior to surgical procedures.

    View details for DOI 10.1186/1744-8069-4-7

    View details for PubMedID 18294378

  • Human in-vivo bioassay for the tissue-specific measurement of nociceptive and inflammatory mediators. Journal of visualized experiments : JoVE Angst, M. S., Tingle, M., Schmelz, M., Carvalho, B., Yeomans, D. C. 2008


    This in-vivo human bioassay can be used to study human volunteers and patients. Samples are collected from pertinent tissue sites such as the skin via aseptically inserted microdialysis catheters (Dermal Dialysis, Erlangen, Germany). Illustrated in this example is the collection of interstitial fluid from experimentally inflamed skin in human volunteers. Sample collection can be combined with other experimental tests. For example, the simultaneous assessment of locally released biochemicals and subjective sensitivity to painful stimuli in experimentally inflamed skin provides the critical biochemical-behavioral link to identify biomarkers of pain and inflammation. Presented assay in the living human organism allows for mechanistic insight into tissue-specific processes underlying pain and/or inflammation. The method is also well suited to examine the effectiveness of existing or novel interventions--such as new drug candidates - targeting the treatment of painful and/or inflammatory conditions. This article will provide a detailed description on the use of microdialysis techniques for collecting interstitial fluid from experimentally inflamed skin lesion of human study subjects. Interstitial fluid samples are typically processed with aid of multiplex bead array immunoassays allowing assaying up to 100 analytes in samples as small in volume as 50 microliters.

    View details for DOI 10.3791/1074

    View details for PubMedID 19229167

  • Morphine reduces local cytokine expression and neutrophil infiltration after incision MOLECULAR PAIN Clark, J. D., Shi, X., Li, X., Qiao, Y., Liang, D., Angst, M. S., Yeomans, D. C. 2007; 3


    Inflammation and nociceptive sensitization are hallmarks of tissue surrounding surgical incisions. Recent studies demonstrate that several cytokines may participate in the enhancement of nociception near these wounds. Since opioids like morphine interact with neutrophils and other immunocytes, it is possible that morphine exerts some of its antinociceptive action after surgical incision by altering the vigor of the inflammatory response. On the other hand, keratinocytes also express opioid receptors and have the capacity to produce cytokines after injury. Our studies were directed towards determining if opioids alter cytokine production near incisions and to identify cell populations responsible for producing these cytokines.A murine incisional model was used to measure the effects of acute morphine administration (0.1-10 mg/kg) on nociceptive thresholds, neutrophil infiltration and cytokine production in hind paw skin 30 minutes and 2 hours after incision. Incised hind paws displayed profound allodynia which was reduced by morphine (0.1-10 mg/kg) in the 2 hours following incision. Skin samples harvested from these mice showed enhanced levels of 5 cytokines: IL-1 beta, IL-6, tumor necrosis factor alpha (TNFalpha), granulocyte colony stimulating factor (G-CSF) and keratinocyte-derived cytokine (KC). Morphine reduced these incision-stimulated levels. Separate analyses measuring myeloperoxidase (MPO) and using immunohistochemistry demonstrated that morphine dose-dependently reduced the infiltration of neutrophils into the peri-incisional tissue. The dose of morphine required for reduction of cytokine accumulation, however, was below that required for inhibition of peri-incisional neutrophil infiltration. Additional immunohistochemical studies revealed wound edge keratinocytes as being an important source of cytokines in the acute phase after incision.Acute morphine administration of doses as low as 0.1 mg/kg reduces peri-incisional cytokine expression. A reduction in neutrophil infiltration does not provide a complete explanation for this effect, and keratinocytes may be responsible for some incision area cytokine production. These studies suggest that morphine may alter the inflammatory milieu of incisional wounds, but these alterations do not likely contribute significantly to analgesia in the acute setting.

    View details for DOI 10.1186/1744-8069-3-28

    View details for PubMedID 17908329

  • When Opioids cause pain JOURNAL OF CLINICAL ONCOLOGY Davis, M. P., Shaiova, L. A., Angst, M. S. 2007; 25 (28): 4497-4498

    View details for DOI 10.1200/JCO.2006.09.1462

    View details for Web of Science ID 000251073300028

    View details for PubMedID 17906213

  • Comment on Koltzenburg et al.: Differential sensitivity of three experimental pain models in detecting the analgesic effects of transdermal fentanyl and buprenorphine. Pain 2006;126 : 165-74 PAIN Angst, M. S., Clark, J. D. 2007; 128 (3): 292-294

    View details for DOI 10.1016/j.pain.2006.12.024

    View details for Web of Science ID 000245908700023

    View details for PubMedID 17276008

  • Experimental heat pain for detecting pregnancy-induced analgesia in humans ANESTHESIA AND ANALGESIA Carvalho, B., Angst, M. S., Fuller, A. J., Lin, E., Mathusamy, A. D., Riley, E. T. 2006; 103 (5): 1283-1287


    Animal studies suggest that increased circulating estrogen and progesterone, and activation of the endorphin system cause prenancy-induced antinociceptive effects. Human studies have provided inconsistent results and have often lacked a nonpregnant control group. In this study, we compared sensitivity to experimental heat and cold pain in pregnant and nonpregnant women. Nineteen healthy nonpregnant female volunteers and 20 pregnant women at term were enrolled. Pain threshold and tolerance were examined using experimental heat-induced pain and cold pressor pain models. Subjects were evaluated pre- and 1-2 days post-delivery (pregnant), or on consecutive days (nonpregnant). Heat pain tolerance was significantly increased in the pregnant women during pre and postdelivery when compared with nonpregnant controls (50.0 +/- 1.0 vs 49.0 +/- 1.2 and 50.1 +/- 0.7 vs 49.2 +/- 1.2 degrees C; mean +/- sd). However, pain induced by the cold pressor test was endured for a similar amount of time by both study groups. Pregnancy-induced analgesic effects at term can be detected in a model of experimental heat pain. These effects persist during the first 24-48 h after delivery. Experimental heat pain is a suitable modality for further characterizing the phenomenon of pregnancy-induced analgesia in humans.

    View details for DOI 10.1213/01.ane.0000239224.48719.28

    View details for PubMedID 17056970

  • Blockade of the complement C5a receptor reduces incisional allodynia, edema, and cytokine expression ANESTHESIOLOGY Clark, J. D., Qiao, Y., Li, X., Shi, X., Angst, M. S., Yeomans, D. C. 2006; 104 (6): 1274-1282


    Activation of the complement system is one component of the inflammatory response. Various components of the complement system participate in killing foreign organisms, recruiting immune cells, enhancing edema, and stimulating cytokine formation. Complement-mediated enhancement of the inflammation surrounding surgical incisions may increase pain.In these studies, the authors used a murine hind paw incisional model to study the role of the complement C5a receptor in supporting incisional inflammation. At baseline and at various time points after incision, they measured the effects of a highly selective C5a receptor antagonist on nociceptive thresholds, edema formation, and cytokine production in the skin surrounding the incision. They also measured changes in C5a receptor expression near the incisions.The once-daily injection of the C5a receptor antagonist AcF-[OPdChaWR] reduced mechanical allodynia and edema in the incised hind paw. A multiplexed cytokine assay revealed that 8 of the 18 cytokines examined showed significant increases in skin tissue abundance after incision. Distinct time courses for the patterns of elevation were seen, though some degree of resolution occurred for all cytokines within 96 h. For 7 of these 8 cytokines, the C5a receptor antagonist reduced the enhancement of expression. In addition, the authors found that the C5a receptor messenger RNA level increased 15-fold in the skin surrounding the incisions within 24 h and then slowly declined.The tissue directly surrounding incisions in mouse hind paws undergoes large changes in the content of specific cytokines in addition to demonstrating edema and nociceptive sensitization. By blocking the receptor for one component of the complement system, C5a, all of these changes can be reduced. Complement receptor inhibitors may constitute a novel group of compounds useful in reducing the pain and swelling of surgical incisions.

    View details for PubMedID 16732100

  • Opioid-induced hyperalgesia - A qualitative systematic review ANESTHESIOLOGY Angst, M. S., Clark, J. D. 2006; 104 (3): 570-587


    Opioids are the cornerstone therapy for the treatment of moderate to severe pain. Although common concerns regarding the use of opioids include the potential for detrimental side effects, physical dependence, and addiction, accumulating evidence suggests that opioids may yet cause another problem, often referred to as opioid-induced hyperalgesia. Somewhat paradoxically, opioid therapy aiming at alleviating pain may render patients more sensitive to pain and potentially may aggravate their preexisting pain. This review provides a comprehensive summary of basic and clinical research concerning opioid-induced hyperalgesia, suggests a framework for organizing pertinent information, delineates the status quo of our knowledge, identifies potential clinical implications, and discusses future research directions.

    View details for PubMedID 16508405

  • Pharmacology of drugs formulated with DepoFoaM (TM) - A sustained release drug delivery system for parenteral administration using multivesicular liposome technology CLINICAL PHARMACOKINETICS Angst, M. S., Drover, D. R. 2006; 45 (12): 1153-1176


    Lamellar liposome technology has been used for several decades to produce sustained-release drug formulations for parenteral administration. Multivesicular liposomes are structurally distinct from lamellar liposomes and consist of an aggregation of hundreds of water-filled polyhedral compartments separated by bi-layered lipid septa. The unique architecture of multivesicular liposomes allows encapsulating drug with greater efficiency, provides robust structural stability and ensures reliable, steady and prolonged drug release. The favourable characteristics of multivesicular liposomes have resulted in many drug formulations exploiting this technology, which is proprietary and referred to as DepoFoam. Currently, two formulations using multivesicular liposome technology are approved by the US FDA for clinical use, and many more formulations are at an experimental developmental stage. The first clinically available formulation contains the antineoplastic agent cytarabine (DepoCyt) for its intrathecal injection in the treatment of malignant lymphomatous meningitis. Intrathecal injection of DepoCyt reliably results in the sustained release of cytarabine and produces cytotoxic concentrations in cerebrospinal fluid (CSF) that are maintained for at least 2 weeks. Early efficacy data suggest that DepoCyt is fairly well tolerated, and its use allows reduced dosing frequency from twice a week to once every other week and may improve the outcome compared with frequent intrathecal injections of unencapsulated cytarabine. The second available formulation contains morphine (DepoDur) for its single epidural injection in the treatment of postoperative pain. While animal studies confirm that epidural injection of DepoDur results in the sustained release of morphine into CSF, the CSF pharmacokinetics have not been determined in humans. Clinical studies suggest that the use of DepoDur decreases the amount of systemically administered analgesics needed for adequate postoperative pain control. It may also provide superior pain control during the first 1-2 postoperative days compared with epidural administration of unencapsulated morphine or intravenous administration of an opioid. However, at this timepoint the overall clinical utility of DepoDur has yet to be defined and some safety concerns remain because of the unknown CSF pharmacokinetics of DepoDur in humans. The versatility of multivesicular liposome technology is reflected by the many agents including small inorganic and organic molecules and macromolecules including proteins that have successfully been encapsulated. Data concerning many experimental formulations containing antineoplastic, antibacterial and antiviral agents underscore the sustained, steady and reliable release of these compounds from multivesicular liposomes after injection by the intrathecal, subcutaneous, intramuscular, intraperitoneal and intraocular routes. Contingent on the specific formulation and manufacturing process, agents were released over a period of hours to weeks as reflected by a 2- to 400-fold increase in elimination half life. Published data further suggest that the encapsulation process preserves bioactivity of agents as delicate as proteins and supports the view that examined multivesicular liposomes were non-toxic at studied doses. The task ahead will be to examine whether the beneficial structural and pharmacokinetic properties of multivesicular liposome formulations will translate into improved clinical outcomes, either because of decreased drug toxicity or increased drug efficacy.

    View details for PubMedID 17112293

  • Opioid tolerance and hyperalgesia in chronic pain patients after one month of oral morphine therapy: A preliminary prospective study JOURNAL OF PAIN Chu, L. F., Clark, D. J., Angst, M. S. 2006; 7 (1): 43-48


    There is accumulating evidence that opioid therapy might not only be associated with the development of tolerance but also with an increased sensitivity to pain, a condition referred to as opioid-induced hyperalgesia (OIH). However, there are no prospective studies documenting the development of opioid tolerance or OIH in patients with chronic pain. This preliminary study in 6 patients with chronic low back pain prospectively evaluated the development of tolerance and OIH. Patients were assessed before and 1 month after initiating oral morphine therapy. The cold pressor test and experimental heat pain were used to measure pain sensitivity before and during a target-controlled infusion with the short-acting mu opioid agonist remifentanil. In the cold pressor test, all patients became hyperalgesic as well as tolerant after 1 month of oral morphine therapy. In a model of heat pain, patients exhibited no hyperalgesia, although tolerance could not be evaluated. These results provide the first prospective evidence for the development of analgesic tolerance and OIH by using experimental pain in patients with chronic back pain. This study also validated methodology for prospectively studying these phenomena in larger populations of pain patients.Experimental evidence suggests that opioid tolerance and opioid-induced hyperalgesia might limit the clinical utility of opioids in controlling chronic pain. This study validates a pharmacologic approach to study these phenomena prospectively in chronic pain patients and suggests that both conditions do occur within 1 month of initiating opioid therapy.

    View details for DOI 10.1016/j.jpain.2005.08.001

    View details for PubMedID 16414554

  • Activation of naloxone-sensitive and -insensitive inhibitory systems in a human pain model JOURNAL OF PAIN Koppert, W., Filitz, J., Troster, A., Ihmsen, H., Angst, M., Flor, H., Schuttler, J., Schmelz, M. 2005; 6 (11): 757-764


    We investigated naloxone effects in a model of electrically induced pain and hyperalgesia. In a double-blind, placebo-controlled, cross-over study, 15 volunteers underwent four 150-minute sessions of high-current-density electrical stimulation of their forearms. After 60 minutes, naloxone or placebo was given intravenously (increasing plasma concentrations of 0.1, 1, and 10 ng/mL; 30 minutes each) in 3 of the 4 sessions. Pain ratings and areas of mechanical hyperalgesia were assessed at regular intervals during all sessions. The low doses of naloxone did not cause any significant change of pain rating of areas of hyperalgesia. In terms of intrasession effects, pain ratings and areas of hyperalgesia significantly decreased during the sessions to 62% (pain rating), 70% (area of punctuate hyperalgesia), and 82% (area of allodynia) of the initial values. Naloxone (10 ng/ml) reversed these decreases. In terms of between-session effects, the time course of pain ratings remained constant from session to session. In contrast, the areas of punctate hyperalgesia successively decreased to 60% of initial value at the fourth repetition. The session effect was not reversed by naloxone. High-current-density electrical stimulation provokes central sensitization, but in addition inhibitory systems are activated that are only partly naloxone-sensitive.Endogenous inhibitory systems are of major importance for clinical pain conditions, but are not reflected in traditional human pain models. Here we show activation of a naloxone-sensitive short-term and a naloxone-insensitive long-term inhibitory system in a new model of electrically induced pain and hyperalgesia.

    View details for DOI 10.1016/j.jpain.2005.07.002

    View details for Web of Science ID 000233497900006

    View details for PubMedID 16275600

  • Mild intraoperative hypothermia during surgery for intracranial aneurysm NEW ENGLAND JOURNAL OF MEDICINE Todd, M. M., Hindman, B. J., Clarke, W. R., Torner, J. C., Todd, M., Hindman, B., Clarke, W., Chaloner, K., Torner, J., Davis, P., Howard, M., Tranel, D., Anderson, S., Todd, M., Hindman, B., Weeks, J., Moss, L., Winn, J., Clarke, W., Chaloner, K., Wichman, M., Peters, R., Hansen, M., Anderson, D., Lang, J., Yoo, B., Adams, H., Clifton, G., Gelb, A., Loftus, C., Schubert, A., Warner, D., Young, W., Frankowski, R., Kieburtz, K., Prough, D., Sternau, L., Marler, J., Moy, C., Matta, B., Kirkpatrick, P., Chatfield, D., Skilbeck, C., Kirollos, R., Rasulo, F., English, K., Duffy, C., Pedersen, K., Scurrah, N., Burnstein, R., Prabhu, A., Salmond, C., Blackwell, A., Birrell, J., Jackson, S., Kassell, N., Pajewski, T., Fraley, H., Morris, A., Alden, T., Shaffrey, M., Bogdonoff, D., Durieux, M., Zuo, Z., Littlewood, K., Nemergut, E., Bedford, R., Stone, D., Balestrieri, P., Mason, J., Henry, G., Ting, P., Shafer, J., Blount, T., Kim, L., James, A., Farace, E., Clark, L., Irons, M., Sasaki, T., Webb, K., Short, T., Mee, E., Ormrod, J., Jane, J., Alden, T., Heppner, P., Olson, S., Ellegala, D., Lind, C., Sheehan, J., Woodfield, M., Law, A., Harrison, M., DAVIES, P., Campbell, D., Robertson, N., Fry, R., Sage, D., Laurent, S., Bradfield, C., Pedersen, K., Smith, K., Young, Y., Chambers, C., Hodkinson, B., Biddulph, J., Jensen, L., Ogden, J., Thayer, Z., Lee, F., Crump, S., Quaedackers, J., Wray, A., Roelfsema, V., Greif, R., Kleinpeter, G., Lothaller, C., Knosp, E., Pfisterer, W., Schatzer, R., Salem, C., Kutalek, W., Tuerkkan, E., Koller, L., Weber, T., Buchmann, A., Merhaut, C., Graf, M., Rapf, B., Lam, A., NEWELL, D., Tanzi, P., Lee, L., Domino, K., Vavilala, M., Bramhall, J., Souter, M., Britz, G., Winn, H., Bybee, H., Costello, T., Murphy, M., Harris, K., Thien, C., Nye, D., Han, T., McNeill, P., O'Brien, B., Cormack, J., Wyss, A., Grauer, R., Popovic, R., Jones, S., Deam, R., Heard, G., Watson, R., Evered, L., Bardenhagen, F., Meade, C., Haartsen, J., Kruger, J., Wilson, M., Maktabi, M., Traynelis, V., McAllister, A., Leonard, P., Hindman, B., Brian, J., Mensink, F., From, R., Papworth, D., Schmid, P., Dehring, D., Howard, M., Hitchon, P., VanGilder, J., Weeks, J., Moss, L., Manzel, K., Anderson, S., Tack, R., Taggard, D., Lennarson, P., Menhusen, M., Gelb, A., Lownie, S., Craen, R., Novick, T., Ferguson, G., Duggal, N., Findlay, J., Ng, W., Cowie, D., Badner, N., Herrick, I., Smith, H., Heard, G., Peterson, R., Howell, J., Lindsey, L., Carriere, L., von Lewinski, M., Schaefer, B., Bisnaire, D., Doyle-Pettypiece, P., McTaggart, M., Giannotta, S., Zelman, V., Thomson, E., Babayan, E., McCleary, C., Fishback, D., Samra, S., Thompson, B., Chandler, W., McGillicuddy, J., Tremper, K., Turner, C., Smythe, P., Dy, E., Pai, S., Portman, V., Palmisano, J., Auer, D., Quigley, M., Giordani, B., Freymuth, A., Scott, P., Silbergleit, R., Hickenbottom, S., Litt, L., Lawton, M., Hannegan, L., Gupta, D., Bickler, P., Dodson, B., Talke, P., Rampil, I., Chen, B., Wright, P., Mitchell, J., Ryan, S., Walker, J., Quinnine, N., Applebury, C., Myles, P., Rosenfeld, J., Hunt, J., Wallace, S., D'Urso, P., Thien, C., McMahon, J., Wadanamby, S., Siu, K., Malham, G., Laidlaw, J., Salerno, S., Alatakis, S., Madder, H., Cairo, S., Konstantatos, A., Smart, J., Lindholm, D., Bain, D., Machlin, H., Moloney, J., Buckland, M., Silvers, A., Downey, G., Molnar, A., Langley, M., McIlroy, D., Daly, D., Bennett, P., Forlano, L., Testa, R., Burnett, W., Johnson, F., Angliss, M., Fletcher, H., Manninen, P., Wallace, M., Lukitto, K., Tymianski, M., Porter, P., Gentili, F., El-Beheiry, H., Mosa, M., Mak, P., Balki, M., Shaikh, S., Sawyer, R., Quader, K., Chelliah, R., Berklayd, P., Merah, N., Ghazali, G., McAndrews, M., Ridgley, J., Odukoya, O., Yantha, S., Wilson, J., Petrozza, P., Miller, C., O'Brien, K., Tong, C., Olympio, M., Reynolds, J., Colonna, D., Glazier, S., Nobles, S., Hill, D., Hulbert, H., Jenkins, W., Lanier, W., Piepgras, D., Wilson, R., Meyer, F., Atkinson, J., Link, M., Weglinski, M., Berge, K., McGregor, D., Trenerry, M., Smith, G., Walkes, J., Felmlee-Devine, M., Van Aken, H., Greiner, C., Freise, H., Brors, H., Hahnenkamp, K., de Oliveira, N. M., Schul, C., Moskopp, D., Greiner, C., Woelfer, J., Hoenemann, C., Gramke, H., Bone, H., Gibmeier, I., Wirtz, S., Lohmann, H., Freyhoff, J., Bauer, B., Hogan, K., Dempsey, R., Rusy, D., Badie, B., Iskandar, B., Resnick, D., Deshmukh, P., Fitzpatrick, J., Sasse, F., Broderick, T., Willmann, K., Connery, L., Kish, J., Weasler, C., Page, N., Hermann, B., Jones, J., Dulli, D., Stanko, H., Geraghty, M., Elbe, R., Salevsky, F., Leblanc, R., Lapointe, N., MacGregor, H., Sinclair, D., Sirhan, D., Maleki, M., Abou-Madi, M., Chartrand, D., Angle, M., Milovan, D., Painchaud, Y., Mirski, M., Tamargo, R., Rice, S., Olivi, A., Kim, D., Rigamonti, D., Naff, N., Hemstreet, M., Berkow, L., Chery, P., Ulatowski, J., Moore, L., CUNNINGHAM, T., McBee, N., Hartman, T., Heidler, J., HILLIS, A., Tuffiash, E., Chase, C., Kane, A., Greene-Chandos, D., Torbey, M., Ziai, W., Lane, K., Bhardwaj, A., Subhas, N., Schubert, A., Mayberg, M., Beven, M., Rasmussen, P., Bhatia, S., Ebrahim, Z., Lotto, M., Vasarhelyi, F., Munis, J., GRAVES, K., Woletz, J., Chelune, G., Samples, S., Evans, J., Blair, D., Abou-Chebl, A., Shutway, F., Manke, D., Beven, C., Fogarty-Mack, P., Stieg, P., Eliazo, R., Li, P., Riina, H., Lien, C., Ravdin, L., Wang, J., Kuo, Y., Jaffe, R., Steinberg, G., Luu, D., Chang, S., Giffard, R., Lemmens, H., Morgan, R., Mathur, A., Angst, M., Meyer, A., Yi, H., Karzmark, P., Bell-Stephens, T., Marcellus, M., Sneyd, J., Pobereskin, L., Salsbury, S., Whitfield, P., Sawyer, R., Dashfield, A., Struthers, R., DAVIES, P., Rushton, A., Petty, V., Harding, S., Richardson, E., Yonas, H., Gyulai, F., Kirby, L., Kassam, A., Bircher, N., Meng, L., Krugh, J., Seever, G., Hendrickson, R., Gebel, J., Cowie, D., Fabinyi, G., Poustie, S., Davis, G., Drnda, A., Chandrasekara, D., Sturm, J., Phan, T., Shelton, A., Clausen, M., Micallef, S., Sills, A., Steinman, F., Sutton, P., Sanders, J., Van Alstine, D., Leggett, D., Cunningham, E., Hamm, W., Frankel, B., Sorenson, J., Atkins, L., Redmond, A., Dalrymple, S., Black, S., Fisher, W., Hall, C., Wilhite, D., Moore, T., Blanton, I. P., Sha, Z., Szmuk, P., Kim, D., Ashtari, A., Hagberg, C., Matuszczak, M., Shahen, A., Moise, O., Novy, D., Govindaraj, R., Jameson, L., Breeze, R., Awad, I., Mattison, R., ANDERSON, T., Salvia, L., Mosier, M., Loftus, C., Smith, J., Lilley, W., White, B., Lenaerts, M. 2005; 352 (2): 135-145


    Surgery for intracranial aneurysm often results in postoperative neurologic deficits. We conducted a randomized trial at 30 centers to determine whether intraoperative cooling during open craniotomy would improve the outcome among patients with acute aneurysmal subarachnoid hemorrhage.A total of 1001 patients with a preoperative World Federation of Neurological Surgeons score of I, II, or III ("good-grade patients"), who had had a subarachnoid hemorrhage no more than 14 days before planned surgical aneurysm clipping, were randomly assigned to intraoperative hypothermia (target temperature, 33 degrees C, with the use of surface cooling techniques) or normothermia (target temperature, 36.5 degrees C). Patients were followed closely postoperatively and examined approximately 90 days after surgery, at which time a Glasgow Outcome Score was assigned.There were no significant differences between the group assigned to intraoperative hypothermia and the group assigned to normothermia in the duration of stay in the intensive care unit, the total length of hospitalization, the rates of death at follow-up (6 percent in both groups), or the destination at discharge (home or another hospital, among surviving patients). At the final follow-up, 329 of 499 patients in the hypothermia group had a Glasgow Outcome Score of 1 (good outcome), as compared with 314 of 501 patients in the normothermia group (66 percent vs. 63 percent; odds ratio, 1.14; 95 percent confidence interval, 0.88 to 1.48; P=0.32). Postoperative bacteremia was more common in the hypothermia group than in the normothermia group (5 percent vs. 3 percent, P=0.05).Intraoperative hypothermia did not improve the neurologic outcome after craniotomy among good-grade patients with aneurysmal subarachnoid hemorrhage.

    View details for Web of Science ID 000226251700006

    View details for PubMedID 15647576

  • Dexmedetomidine and opioid interactions: Defining the role of dexmedetomidine for intensive care unit sedation ANESTHESIOLOGY Maze, M., Angst, M. S. 2004; 101 (5): 1059-1061

    View details for Web of Science ID 000224738600001

    View details for PubMedID 15505438

  • Management of perioperative pain in patients chronically consuming opioids REGIONAL ANESTHESIA AND PAIN MEDICINE Carroll, I. R., Angst, M. S., Clark, J. D. 2004; 29 (6): 576-591


    The prevalence of licit and illicit opioid use is growing, and a greater percentage of chronically opioid-consuming patients are presenting for surgery. These patients can be expected to experience increased postoperative pain, greater postoperative opioid consumption, and prolonged use of healthcare resources for managing their pain.Achieving adequate pain control in these patients can be challenging because commonly used strategies for alleviating postoperative pain may have diminished effectiveness. We explore the prevalence and characteristics of opioid use in the United States and discuss its impact on the perioperative management of pain. We examine mechanistically why adequate perioperative pain control in chronically opioid-consuming patients may be difficult.We present strategies for providing adequate analgesia to these patients that include the optimal use of opioids, adjuvant medications, and regional anesthetic techniques.

    View details for DOI 10.1016/j.rapm.2004.06.009

    View details for PubMedID 15635517

  • Comparative analgesic and mental effects of increasing plasma concentrations of dexmedetomidine and alfentanil in humans ANESTHESIOLOGY Angst, M. S., Ramaswamy, B., Davies, M. F., Maze, M. 2004; 101 (3): 744-752


    In animals, systemic and intrathecal administration of the alpha2 -adrenergic receptor agonist dexmedetomidine results in robust antinociceptive effects in models of heat pain. In humans, systemically administered dexmedetomidine is approved for sedating patients in the intensive care unit. However, whether systemic administration of dexmedetomidine in humans produces significant analgesia at doses causing sedation but not unconsciousness remains controversial.This study in human volunteers used a placebo-controlled, double-blind, and randomized design to examine whether dexmedetomidine at doses causing mild to severe sedation produces analgesia in experimental models of heat and electrical pain. Results were compared to the effects of the mu-opioid receptor agonist alfentanil. A computer-controlled infusion provided four median step-up plasma concentrations of dexmedetomidine (0.09, 0.24, 0.54, and 1.23 ng/ml) and alfentanil (13.4, 33.8, 67.8, and 126.1 ng/ml).Sedative and cognitive effects of dexmedetomidine were dose-dependent, resulting in a median sedation score of 95 of 100 and slowing of cognitive speed (reaction time, trail-making test) by a factor of about two at the highest plasma concentration. Dexmedetomidine did not attenuate heat or electrical pain. Alfentanil caused severe sedation (median sedation score 88 of 100) and slowed cognitive speed by a factor of approximately 1.4 at the highest plasma concentration. Alfentanil attenuated heat and electrical pain dose dependently.This study documents that systemic dexmedetomidine lacks analgesic efficacy for heat and electrical pain at doses causing mild to severe sedation. These results provide further evidence suggesting that systemic administration of dexmedetomidine lacks broad analgesic activity in models of acute pain at doses not rendering humans unconscious.

    View details for PubMedID 15329600

  • Pancreatic Surgery Anesthesiologist’s Manual of Surgical Procedures Norton, J. A., Angst, M. S. edited by Jaffe, R. A., Samuels, S. Lippincott Williams & Wilkins. 2004; 3
  • Peritoneal Surgery Anesthesiologist’s Manual of Surgical Procedures Norton, J. A., Oberhelmen, H. A., Angst, M. S. edited by Jaffe, R. A., Samuels, S. 2004; 3
  • The site of action of epidural fentanyl in humans: The difference between infusion and bolus administration Annual Meeting of the Society-of-Obstetric-Anesthesiology-and-Perinatology Ginosar, Y., Riley, E. T., Angst, M. S. LIPPINCOTT WILLIAMS & WILKINS. 2003: 1428–38


    Most published studies suggesting that epidural fentanyl acts predominantly at spinal sites administered the drug as a bolus injection, whereas most studies suggesting that it acts predominantly at supraspinal sites administered the drug as an infusion. In this study we tested the hypothesis that the mode of administration (bolus versus infusion) of epidural fentanyl determines its site of action. Ten healthy volunteers were enrolled in this randomized, double-blinded, cross-over study. On separate study days fentanyl was administered into the epidural space as a bolus (0.03 mg followed by 0.1 mg 210 min later) and as an infusion (0.03 mg/h followed by 0.1 mg/hr 210 min later for 200 min). Using a thermal and electrical experimental pain model, the heat ( degrees C) and electrical current (mA) causing maximum tolerable pain were assessed repetitively over a period of 420 min. The analgesic efficacy measures were obtained at a lumbar and a cranial dermatome. Plasma fentanyl concentrations were determined throughout the study. Epidural bolus administration of fentanyl resulted in segmental analgesia (leg > head), whereas the epidural infusion of fentanyl produced nonsegmental analgesia (leg = head). There was a significant linear relationship between the analgesic effect and the plasma concentration of fentanyl for the epidural infusion but not for the epidural bolus administration of fentanyl. These findings support our hypothesis and might explain the apparent conflict in the literature regarding the site of action of epidural fentanyl.In an experimental pain study in volunteers, epidural fentanyl caused segmental analgesia when administered as a bolus and nonsegmental systemic analgesia when administered as a continuous infusion. This finding may help resolve the long-standing controversy surrounding the site of action of epidural fentanyl.

    View details for DOI 10.1213/01.ANE.0000081793.60059.10

    View details for PubMedID 14570661

  • The site of action of epidural fentanyl infusions in the presence of local anesthetics: A minimum local analgesic concentration infusion study in nulliparous labor Annual Meeting of the Society-of-Obstetric-Anesthesiology-and-Perinatology Ginosar, Y., Columb, M. O., Cohen, S. E., Mirikatani, E., Tingle, M. S., Ratner, E. F., Angst, M. S., Riley, E. T. LIPPINCOTT WILLIAMS & WILKINS. 2003: 1439–45


    We have previously demonstrated that continuous epidural infusions of fentanyl without local anesthetics elicit analgesia by a systemic mechanism. In this study, we examined the hypothesis that, in the presence of epidural bupivacaine, continuous infusions of epidural fentanyl elicit analgesia by a spinal mechanism. Forty-eight nulliparous women in active labor participated in this prospective, randomized, double-blinded study. Women received lumbar epidural analgesia with 20-30 mL bupivacaine 0.125% until pain free. Subjects were then randomized to either IV or epidural (EPI) fentanyl infusion groups. Each infusion delivered fentanyl 30 microg/h. All women received an epidural infusion of bupivacaine at a rate of 20 mL/h, the concentration of which was determined by the response of the previous woman in the same group to the analgesic regimen used. Unlike previous studies that assessed the minimum local analgesic concentration (MLAC) for bolus administration at the initiation of analgesia, this study assessed MLAC(infusion) for the maintenance of analgesia throughout the first stage of labor. MLAC(infusion) was determined using the up-down sequential analysis described by Dixon and Massey. The MLAC(infusion) of epidural bupivacaine was 0.063% (95% confidence interval, 0.058-0.068) and 0.019% (95% confidence interval, 0.000-0.038) in the IV and EPI groups respectively. A continuous infusion of fentanyl was more than three times as potent when administered by the epidural than by the IV route. This marked increase in potency for the epidural route is highly suggestive for a predominantly spinal mechanism of action for infused epidural fentanyl under the conditions of this study.This study determined the median effective concentration for epidural infusions of bupivacaine during labor analgesia. Coadministered epidural fentanyl infusions were more than three times more potent than IV fentanyl infusions, suggesting a predominantly spinal mechanism of opioid action under these study conditions.

    View details for DOI 10.1213/01.ANE.0000081792.84877.A2

    View details for Web of Science ID 000186143600038

    View details for PubMedID 14570662

  • Short-term infusion of the mu-opioid agonist remifentanil in humans causes hyperalgesia during withdrawal PAIN Angst, M. S., Koppert, W., Pahl, I., Clark, D. J., Schmelz, M. 2003; 106 (1-2): 49-57


    Numerous animal studies suggest that acute and chronic exposure to opioids can be associated with the development of hyperalgesia, i.e. an increased sensitivity to noxious stimuli. Hyperalgesia has been documented during withdrawal and on occasion while animals were still exposed to opioids. A pivotal role in the genesis of opioid-associated hyperalgesia has been attributed to a pain facilitating system involving the N-methyl-D-aspartate (NMDA)-receptor. In humans little direct evidence documents opioid-associated hyperalgesia, albeit observational data suggest that such hyperalgesia may be relevant in a clinical context. This study used a double blind, randomized, crossover and placebo-controlled design to test in opioid-naïve, healthy human volunteers whether hyperalgesia would develop within 30 min of stopping a 90-min infusion with the mu-opioid agonist remifentanil, and whether co-administration of the NMDA-receptor antagonist S-ketamine would prevent such hyperalgesia. We found that a skin area with pre-existing mechanical hyperalgesia was significantly enlarged after stopping the remifentanil infusion. However, the pain response to heat assessed in regular skin was not different before and after the infusion of remifentanil. Co-administration of the NMDA-receptor antagonist S-ketamine abolished observed enlargement of the hyperalgesic skin area. This study provides direct evidence in humans that short-term administration of an opioid can enhance hyperalgesia as observed during withdrawal and points to a potential role of the NMDA-receptor system in mediating such a hyperalgesic response. This study also points to a differential susceptibility of different pain modalities for the expression of hyperalgesia associated with opioid administration.

    View details for DOI 10.1016/S0304-3959(03)00276-8

    View details for PubMedID 14581110

  • Naloxone provokes similar pain facilitation as observed after short-term infusion of remifentanil in humans PAIN Koppert, W., Angst, M., Alsheimer, M., Sittl, R., Albrecht, S., Schuttler, J., Martin, S. 2003; 106 (1-2): 91-99


    In contrast to an expected preventive analgesic effect, clinical observations suggest that intraoperatively applied opioids can induce postoperative hyperalgesia. We tested the development of post-infusion hyperalgesia in a newly developed experimental model of electrically induced pain and secondary mechanical hyperalgesia. In a double-blind, placebo controlled, cross-over study, 13 subjects received either saline placebo, remifentanil (0.05 or 0.1 microg/kg/min) or naloxone (0.01 mg/kg). Remifentanil dose-dependently reduced pain and mechanical hyperalgesia during the infusion, but upon withdrawal, pain and hyperalgesia increased significantly above control level (p<0.01 and p<0.05, respectively). Naloxone infusion similarly resulted in increased pain (anti-analgesia) (p<0.001) and mechanical hyperalgesia (p<0.01). Increased pain ratings following withdrawal of remifentanil significantly correlated to anti-analgesia evoked by the mu-opioid antagonist naloxone (p<0.01) and was of similar magnitude, suggesting inhibition of endogenous opioids as an underlying mechanism. In contrast, hyperalgesia after remifentanil was more pronounced than hyperalgesia after naloxone administration and did not correlate to the observed anti-analgesic effects, suggesting the involvement of additional receptors systems other than the endorphin system.

    View details for DOI 10.1016/S0304-3959(03)00294-X

    View details for Web of Science ID 000186693400013

    View details for PubMedID 14581115

  • Seizure duration with remifentanil/methohexital vs. methohexital alone in middle-aged patients undergoing electroconvulsive therapy ACTA ANAESTHESIOLOGICA SCANDINAVICA Smith, D. L., Angst, M. S., Brock-Utne, J. G., Debattista, C. 2003; 47 (9): 1064-1066


    The object of this study was to test whether substituting part of the methohexital dose with the short-acting opioid remifentanil would prolong seizure duration in middle-aged patients while providing a similar depth of anesthesia as with methohexital alone. This has been reported for the combined use of methohexital and remifentanil in elderly patients, but has not been investigated in middle-aged patients likely to require a higher total dose of methohexital for inducing anesthesia.Seven patients (42+/-10 years; mean +/-SD) receiving electroconvulsive therapy (ECT) were anesthetized with methohexital (1.25 mg kg-1) or with methohexital (0.625 mg kg-1) plus remifentanil (1 micro g kg-1) in this randomized, double blind, crossover study. Additional methohexital was given as needed until loss of eyelash reflex was observed. Suxamethonium (1 mg kg-1) was used for muscular paralysis.Motor and EEG seizure durations were significantly longer after induction with methohexital plus remifentanil (45+/-14 and 58+/-15 s) than with methohexital alone (31+/-11 and 42+/-18 s). A methohexital dose of 1.2+/-0.3 and 1.9+/-0.3 mg was necessary to achieve loss of eyelash reflex if methohexital was used with and without remifentanil. Peak heart rate after ECT was significantly higher if remifentanil was coadministered with methohexital (148+/-12 vs. 126+/-24 b.p.m).Substituting part of the methohexital dose with remifentanil is a useful anesthetic technique to prolong seizure duration in middle-aged patients requiring a 1.5-fold higher induction dose of methohexital than elderly patients, the only population studied to date for the combined use of methohexital and remifentanil in ECT.

    View details for PubMedID 12969096

  • The mu-opioid agonist remifentanil attenuates hyperalgesia evoked by blunt and punctuated stimuli with different potency: a pharmacological evaluation of the freeze lesion in humans International CPT Congress Lotsch, J., Angst, M. S. ELSEVIER SCIENCE BV. 2003: 151–61


    Experimental pain models inducing hyperalgesia, i.e. an increased sensitivity to noxious stimuli often present in clinical pain, are important tools for studying antinociceptive drug profiles. The correct interpretation of results obtained in these models necessitates their mechanistic understanding. This study evaluated the freeze lesion, an experimental model of hyperalgesia, in humans. Twelve healthy subjects were tested with mechanical (brush, punctuated and blunt) and electrical (5, 250, and 2000 Hz sine wave current) stimuli before and after freezing the skin, and during a computer-controlled infusion of the mu-opioid agonist remifentanil targeting five different plasma concentrations between 0 and 6 ng/ml in a two-staged, single occasion, randomized, and double blind study design. Pharmacodynamic modeling techniques were used to describe the effect of freezing and drug administration on the mechanical and electrical pain thresholds. Freezing the skin resulted in hyperalgesia to blunt and punctuated stimuli and lowered the respective pain threshold by 29 and 73%. Hyperalgesia to brushing or electrical stimuli was not detected. Remifentanil attenuated hyperalgesia to blunt stimuli about twice as potently as hyperalgesia to punctuated stimuli, as indicated by a significantly steeper linear relationship between the remifentanil plasma concentration and the increase of the pain threshold to blunt stimuli. Remifentanil attenuated electrical pain with greater potency for low frequency stimulation. The potency difference of remifentanil suggests that different neuronal mechanisms mediate hyperalgesia to blunt and punctuated stimulation. Absence of brush-evoked and electrical hyperalgesia is compatible with the view that mechanical hyperalgesia to blunt and punctuated stimulation of the freeze lesion is predominantly caused by a peripheral mechanism.

    View details for DOI 10.1016/S0304-3959(02)00349-4

    View details for Web of Science ID 000181712100016

    View details for PubMedID 12620606

  • Input characteristics and bioavailability after administration of immediate and a new extended-release formulation of hydromorphone in healthy volunteers Annual Meeting of the American-Society-of-Anesthesiologists Drover, D. R., Angst, M. S., Valle, M., Ramaswamy, B., Naidu, S., Stanski, D. R., Verotta, D. LIPPINCOTT WILLIAMS & WILKINS. 2002: 827–36


    To compare the pharmacokinetics of intravenous, oral immediate-release (IR), and oral extended-release (OROS ) formulations of hydromorphone.In this randomized, six-session, crossover-design study, 12 subjects received hydromorphone 8-mg intravenous, 8-mg IR oral, and 8-, 16-, and 32-mg OROS formulations or placebo orally followed by plasma sampling for hydromorphone determination. Pharmacokinetic analysis was performed using NONMEM. Using the disposition of hydromorphone from the intravenous administration, deconvolution was used to estimate the input rate function (release rate from the gut to the blood) for the IR and OROS formulations. A linear spline was used to describe the drug input rate function.The deconvolution using linear splines described the release characteristics of both the IR and OROS formulations. The mean absolute bioavailability for the 8-mg OROS formulation was significantly larger ( = 0.025) than for the 8-mg IR formulation: 0.24 (SD 0.059) versus 0.19 (SD 0.054), respectively. The bioavailability was the same for the three doses of the OROS formulation. Predicted degree of fluctuation of plasma concentrations would be expected to be 130% and 39% for the IR and OROS 8-mg doses, respectively.The OROS formulation of hydromorphone produced continued release of medication over 24 h, which should allow for once-daily oral dosing. The extended release of hydromorphone will produce less fluctuation of plasma concentrations compared with IR formulations, which should provide for more constant pain control. The in vivo release of hydromorphone from both IR and OROS formulations were adequately described using a linear spline deconvolution approach. The increased bioavailability from the OROS formulation may be related to decreased metabolism by a first-pass effect or enterohepatic recycling of hydromorphone.

    View details for PubMedID 12357147

  • Opioid-induced hyperalgesia and incisional pain ANESTHESIA AND ANALGESIA Li, X. Q., Angst, M. S., Clark, J. D. 2001; 93 (1): 204-209


    Opioids occupy a position of unsurpassed clinical utility in the treatment of pain of many etiologies. However, recent reports in laboratory animals and humans have documented the occurrence of hyperalgesia when the administration of opioids is abruptly tapered or discontinued, a condition known as opioid-induced hyperalgesia (OIH). In these studies we documented that rats administered morphine (40 mg. kg(-1). day(-1) for 6 days) via subcutaneous osmotic minipumps demonstrated thermal hyperalgesia and mechanical allodynia for several days after the cessation of morphine administration. Additional experiments using a rat model of incisional pain showed that that attributable to OIH were additive with the hyperalgesia and allodynia that resulted from incision. In our final experiments we observed that if naloxone is administered chronically before incision then discontinued (20 mg. kg(-1). day(-1) for 6 days), the hyperalgesia and allodynia that result from hind paw incision was markedly reduced. In contrast, naloxone 1 mg/kg administered acutely after hind paw incision increased hyperalgesia and allodynia. We conclude that the chronic administration of exogenous opioid receptor agonists and antagonists before incision can alter the hyperalgesia and allodynia observed in this pain model, perhaps by altering intrinsic opioidergic systems involved in setting thermal and mechanical nociceptive thresholds. Implications: The chronic administration of opioids followed by abrupt cessation can lead to a state of hyperalgesia. In these studies we demonstrate that the hyperalgesia from opioid cessation and from hind paw incision are additive in rats. We suggest that failure to take into consideration preoperative opioid use can lead to excessive postoperative pain.

    View details for PubMedID 11429366

  • The relationship between tracheal width and left bronchial width: Implications for left-sided double-lumen tube selection JOURNAL OF CARDIOTHORACIC AND VASCULAR ANESTHESIA Brodsky, J. B., Malott, K., Angst, M., Fitzmaurice, B. G., Kee, S. P., Logan, L. 2001; 15 (2): 216-217


    To determine if there is a relationship between tracheal width (TW) and left bronchial width (LBW).Three-dimensional chest computed tomography (CT) scans were used to reconstruct major airways for measurement of TW and LBW.Stanford University Medical Center, Stanford, California.Thirty-one adult patients undergoing chest CT scans.Cursors were used to directly measure internal diameter from coronal images of the trachea at midclavicular level and the left main bronchus at a level 1 cm below the carina.TW and LBW, but not the LBW-to-TW ratio, were significantly larger in men than in women. The LBW-to-TW ratio was consistent for men (0.75 +/- 0.09) and women (0.77 +/- 0.10).LBW is proportional to TW. If LBW cannot be measured directly but TW can, the ratio of LBW to TW can be used to predict LBW. An appropriate-sized left double-lumen tube can then be selected for the patient.

    View details for PubMedID 11312482

  • A murine model of opioid-induced hyperalgesia MOLECULAR BRAIN RESEARCH Li, X. Q., Angst, M. S., Clark, J. D. 2001; 86 (1-2): 56-62


    Controversies surround the possible long-term physiological and psychological consequences of opioid use. Analgesic tolerance and addiction are commonly at the center of these controversies, but other concerns exist as well. A growing body of evidence suggests that hyperalgesia caused by the chronic administration of opioids can occur in laboratory animals and in humans. In these studies we describe a murine model of opioid-induced hyperalgesia (OIH). After the treatment of mice for 6 days with implanted morphine pellets followed by their removal, both thermal hyperalgesia and mechanical allodynia were documented. Additional experiments demonstrated that prior morphine treatment also increased formalin-induced licking behavior. These effects were intensified by intermittent abstinence accomplished through administration of naloxone during morphine treatment. Experiments designed to determine if the mu-opioid receptor mediated OLH in our model revealed that the relatively-selective mu-opioid receptor agonist fentanyl induced the thermal hyperalgesia and mechanical allodynia characteristic of OIH when administered in intermittent boluses over 6 days. In complimentary experiments we found that CXBK mice which have reduced mu-opioid receptor binding displayed no significant OIH after morphine treatment. Finally, we explored the pharmacological sensitivities of OIH. We found that the N-methyl-D-aspartate (NMDA) receptor antagonist MK-801, the nitric oxide synthase (NOS) inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME) and the heme oxygenase (HO) inhibitor tin protoporphyrin (Sn-P) dose-dependently reduced OIH in this model while the NSAID indomethacin had no effect. Thus we have characterized a murine model of OIH which will be useful in the pursuit of the molecular mechanisms underlying this phenomenon.

    View details for PubMedID 11165371

  • Pharmacodynamics of orally administered sustained-release hydromorphone in humans ANESTHESIOLOGY Angst, M. S., Drover, D. R., Lotsch, J., Ramaswamy, B., Naidu, S., Wada, D. R., Stanski, D. R. 2001; 94 (1): 63-73


    The disposition kinetics of hydromorphone generally necessitates oral administration every 4 h of the conventional immediate-release tablet to provide sustained pain relief. This trial examined time course and magnitude of analgesia to experimental pain after administration of sustained-release hydromorphone as compared with that after immediate-release hydromorphone or placebo.Using a 4 x 4 Latin square double-blind design, 12 subjects were randomized to receive a single dose of 8, 16, and 32 mg sustained-release hydromorphone and placebo. The same subjects had received 8 mg immediate-release hydromorphone before this study. Using an electrical experimental pain paradigm, analgesic effects were assessed for up to 30 h after administration, and venous hydromorphone plasma concentrations were measured at corresponding times.The hydromorphone plasma concentration peaked significantly later (12.0 h [12.0--18.0] vs. 0.8 h [0.8--1.0]; median and interquartile range) but was maintained significantly longer at greater than 50% of peak concentration (22.7 +/- 8.2 h vs. 1.1 +/- 0.7 h; mean +/- SD) after sustained-release than after immediate-release hydromorphone. Similarly, sustained-release hydromorphone produced analgesic effects that peaked significantly later (9.0 h [9.0--12.0] vs. 1.5 h [1.0--2.0]) but were maintained significantly longer at greater than 50% of peak analgesic effect (13.3 +/- 6.3 h vs. 3.6 +/- 1.7 h). A statistically significant linear relation between the hydromorphone plasma concentration and the analgesic effect on painful stimuli existed.A single oral dose of a new sustained-release formulation of hydromorphone provided analgesia to experimental pain beyond 24 h of its administration.

    View details for PubMedID 11135723

  • Painless Electrodiagnostic Current Perception Threshold and Pain Tolerance Threshold Values in CRPS Subjects and Healthy Controls: A Multi-Center Study Pain Practice Raj PP, Chado HN, Angst MS, et al. 2001; 1: 53-60
  • Antinociceptive effects of morphine-6-glucuronide in homozygous MDR1a P-glycoprotin knockout and in wildtype mice in the hotplate test LIFE SCIENCES Lotsch, J., Tegeder, I., Angst, M. S., Geisslinger, G. 2000; 66 (24): 2393-2403


    Morphine-6-glucuronide (M6G), a major metabolite of morphine with agonist opioid-receptor activity, was reported to be a substrate of P-glycoprotein (P-gp). Inhibition of P-gp may thus result in higher brain uptake of M6G. The goal of this observer-blinded, placebo controlled study, was to compare the antinociceptive effects of M6G in homozygous P-gp knockout (mdr1a(-/-)) and wildtype (mdr1a(+/+)) mice. M6G was injected intraperitoneally as a single dose of 0, 0.5, 1, 2.5, 5, and 10 mg/kg. Eight P-gp knockout and eight wildtype mice were studied per dose. A hot plate test was performed before and 5, 15, 30, 60, 90, 120, and 150 min after M6G administration. Plasma-concentrations of M6G, morphine, and morphine-3-glucuronide (M3G) were measured after intraperitoneal injection of 5 mg/kg M6G in another 14 P-gp knockout and 14 wildtype mice. No difference neither in the dose response relationship, nor in the time course of response latency times were observed between P-gp knockout and wildtype mice. However, latency times increased with higher doses of M6G, with antinociception significantly different from placebo at a M6G dose of 5 and 10 mg/kg. P-gp knockout mice tended to have higher plasma concentrations than the wildtype. However, plasma concentrations widely overlapped between groups and therefore no statistical significant group difference could be detected. We conclude that despite reported doubling of M6G brain uptake, absence of mdr1a coded P-gp does not enhance antinociceptive effects of M6G in the hotplate test after acute single-dose administration in mdr1a(-/-) knockout mice.

    View details for PubMedID 10864101

  • Insidious intoxication after morphine treatment in renal failure: Delayed onset of morphine-6-glucuronide action ANESTHESIOLOGY Angst, M. S., Buhrer, M., Lotsch, J. 2000; 92 (5): 1473-1476

    View details for PubMedID 10781294

  • Orthotopic liver transplantation for carcinoid tumour metastatic to the liver: anesthetic management CANADIAN JOURNAL OF ANAESTHESIA-JOURNAL CANADIEN D ANESTHESIE Claure, R. E., Drover, D. D., Haddow, G. R., Esquivel, C. O., Angst, M. S. 2000; 47 (4): 334-337


    To report the anesthetic management of a patient with carcinoid tumour metastatic to the liver who presented for orthotopic liver transplantation. Anesthetic implications of metastatic carcinoid tumour on liver transplantation and the use of octreotide are discussed.A 51-yr-old woman with intestinal carcinoid tumour metastatic to the liver presented for orthotopic liver transplantation, a recent treatment option for patients with extensive hepatic carcinoid metastases and disabling symptoms unresponsive to conventional therapy. Despite continuous administration of the somatostatin analogue octreotide via a hepatic artery infusate pump, the patient suffered from daily break through symptoms, which included flushing, palpitations, paroxysmal hypertension, and dyspnea. The patient presented to the operating room with sinus tachycardia and severe arterial hypertension. Octreotide and phentolamine were used to prevent further mediator release and to control the paroxysmal hypertension. Midazolam, fentanyl, thiopental, succinylcholine, vecuronium, and isoflurane were used to induce and maintain anesthesia safely. An intravenous octreotide infusion was initiated after induction and continued throughout the case. Infrequent and non-threatening peaks in arterial blood pressure were readily treated with small intravenous doses of vasoactive drugs and octreotide. No other manifestations of the carcinoid syndrome occurred. The patient had an uneventful recovery and was discharged on postoperative day #6.The patient safely underwent orthotopic liver transplantation for treatment of symptomatic carcinoid tumour metastatic to the liver. The anesthetic management followed recent recommendations favouring the use of octreotide to prevent patients from becoming symptomatic. Outlined dosing regimen for octreotide provided satisfactory hemodynamic stability.

    View details for PubMedID 10764178

  • Lumbar epidural morphine in humans and supraspinal analgesia to experimental heat pain ANESTHESIOLOGY Angst, M. S., Ramaswamy, B., Riley, E. T., Stanski, D. R. 2000; 92 (2): 312-324


    Epidural administration of morphine is a common analgesic technique to manage pain. Morphine spreads from the epidural space to the cerebrospinal fluid and then rostrally, causing side effects mediated by the brain stem. However, data on the rostral spread of morphine-mediated analgesia are sparse. This study examined the rostral spread of analgesic effects on heat and electrical pain after epidural administration of morphine.In a randomized, double-blinded, placebo-controlled, crossover study, 5 mg morphine or saline placebo were injected into the lumbar epidural space in nine healthy volunteers. Correct needle placement was confirmed with fluoroscopy. Analgesia to experimental nociceptive heat and electrical stimuli was measured at lumbar (L4), thoracic (T10), cervical (C2), and trigeminal (V2) levels before and 2, 5, 10, and 24 h after epidural injection. Plasma samples for assaying morphine concentrations were drawn before and after each analgesic evaluation.Epidural morphine significantly attenuated experimental heat pain at all dermatomes tested compared with saline placebo. Analgesic effects were significant at L4 after 2, 5, and 10 h, at T10 after 5, 10, and 24 h, and at V2 after 10 h. Electrical pain was attenuated at the lumbar and thoracic but not at the cervical dermatome. Analgesic effects were significant at L4 after 2, 5, and 10 h and at T10 after 5 and 10 h. Morphine plasma concentrations were below the detection limit (1 ng/ml) in eight of the nine subjects 10 h after epidural injection.Lumbar epidural injection of morphine attenuated cutaneous heat pain up to the trigeminal dermatome during a 24-h observation period. In a clinical context, this implies that some types of pain may be attenuated up to the supraspinal level after lumbar epidural administration of morphine.

    View details for PubMedID 10691216

  • The pharmacokinetics of hydromorphone SR Drover, D. R., Angst, M. S., Naidu, S., Ramaswamy, B. LIPPINCOTT WILLIAMS & WILKINS. 1999: U245
  • The relationship between the visual analog pain intensity and pain relief scale changes during analgesic drug studies in chronic pain patients ANESTHESIOLOGY Angst, M. S., Brose, W. G., Dyck, J. B. 1999; 91 (1): 34-41


    Most analgesic drug studies in humans quantify drug action based on verbal reports of pain intensity and pain relief. Although measures of pain intensity and pain relief show a good overall correlation, it is not known if they relate to each other consistently over time Such consistency is necessary if both measures are used to depict analgesic drug action versus time. This study examined in chronic pain patients if the relationship between visual analog pain intensity and pain relief scores was consistent during two analgesic drug studies.Data from two independently performed analgesic drug studies were analyzed using linear regression. Data were split into pain intensity and pain relief scores recorded before and after patients' experience of maximum analgesia (>90% of maximum pain relief). The slopes of the linear regression line depicting pain intensity versus pain relief scores before and after maximum analgesia were statistically compared.The slope of the linear regression line before and after maximum analgesia was significantly different in both drug studies (nonoverlapping 95% confidence intervals), -2.16+/-0.57 versus -1.05+/-0.10 and -1.47+/-0.26 versus -1.09+/-0.07, respectively. These results are compatible with the observation that patients indicating the same pain intensity before and after maximum analgesia reported a different magnitude of pain relief.The relationship between visual analog pain intensity and pain relief scores changed systematically during both analgesic drug studies. The authors hypothesize that patients' interpretation of the pain relief scale had changed during the studies and therefore suggest using the pain intensity scale to quantify analgesic drug action over time.

    View details for PubMedID 10422926

  • Factors affecting the pharmacokinetic characteristics of rapacuronium ANESTHESIOLOGY Fisher, D. M., Kahwaji, R., Bevan, D., Bikhazi, G., Fragen, R. J., Angst, M. S., Ornstein, E., Matteo, R. S. 1999; 90 (4): 993-1000


    Rapacuronium is a new nondepolarizing muscle relaxant with rapid onset and offset. As part of a study to determine its neuromuscular effects, the authors sampled plasma sparsely to determine the influence of age, gender, and other covariates on its pharmacokinetic characteristics.Of 181 patients receiving a single bolus dose of 0.5-2.5 mg/kg rapacuronium, 43 (aged 24-83 yr) had plasma sampled 3 or 4 times to determine plasma concentrations of rapacuronium and its metabolite, ORG9488. Pharmacokinetic analysis was performed using a population approach (mixed-effects modeling) to determine the influence of demographic characteristics and preoperative laboratory values on the pharmacokinetic parameters.Rapacuronium's weight-normalized plasma clearance was 7.03 x (1 - 0.0507 x (HgB - 13)) ml x kg(-1) x min(-1), where HgB is the patient's preoperative value for hemoglobin (g/100 ml); however, rapacuronium's blood clearance (11.4+/-1.4 ml x kg(-1) x min(-1), mean +/- SD) did not vary with hemoglobin. Rapacuronium's weight-normalized pharmacokinetic parameters were not influenced by age, gender, or other covariates examined. Plasma concentrations of ORG9488 were typically less than 14% those of rapacuronium during the initial 30 min after rapacuronium administration.In this patient population, neither age nor gender influence elimination of rapacuronium. This finding contrasts to an age-related decrease in plasma clearance observed in a study of 10 healthy volunteers and in a pooled analysis of the pharmacokinetic data from 206 adults in multiple clinical studies. Even if ORG9488 has a potency similar to that of rapacuronium, its plasma concentrations after a single bolus dose of rapacuronium are sufficiently small to contribute minimally to neuromuscular blockade.

    View details for Web of Science ID 000079457600010

    View details for PubMedID 10201669

  • Pharmacokinetics, cortisol release, and hemodynamics after intravenous and subcutaneous injection of human corticotropin-releasing factor in humans CLINICAL PHARMACOLOGY & THERAPEUTICS Angst, M. S., Dyck, J. B., Azarnoff, D. L., Goldblum, R., Ho, B., Gfroerer, T., Linton, E. A., Glynn, B. P., Shafer, S. L. 1998; 64 (5): 499-510


    Two clinical trials investigated the pharmacokinetics of human corticotropin-releasing factor (hCRF), resulting cortisol release, and associated hemodynamic changes.In a 3 x 3 Latin square design, subjects were randomized to receive a single dose of 5 microg x kg(-1) hCRF as a 10-minute intravenous infusion, a 180-minute infusion, and a subcutaneous injection in separate study sessions 7 days apart. Twelve additional subjects obtained a subcutaneous dose of either 300, 600, or 1200 microg hCRF on 3 consecutive days. Noncompartmental and compartmental pharmacokinetic analysis was performed. Hemodynamic response was characterized with use of pharmacodynamic models.The volume of distribution at steady state was 9.81 +/- 3.0 and 15.61 +/- 2.9, and the clearance was 256 +/- 40 mL x min(-1) and 345 +/- 90 mL x min(-1) for the 10-minute and 180-minute intravenous infusion, respectively (P < .05). Corresponding elimination half-life was 45 +/- 7 minutes and 37 +/- 10 minutes. Two-compartment and 1-compartment models adequately described the 10-minute and 180-minute infusions, respectively. The bioavailability of hCRF after subcutaneous administration was 67% +/- 17%. Apparent clearance remained unchanged for different subcutaneous doses. Peak plasma cortisol concentrations were similar after subcutaneous and intravenous administration of hCRF. Repetitive administration of hCRF did not result in accumulation but produced a reduced plasma cortisol response. A sigmoidal model related plasma hCRF concentrations to increase in heart rate (maximum, 39 beats x min(-1)). The relationship between the modest decrease in diastolic blood pressure and plasma hCRF concentrations was linear.The pharmacokinetics of intravenously administered hCRF were nonlinear, but apparent clearance was constant for various subcutaneous doses. An excellent bioavailability and preserved bioactivity make the subcutaneous route an attractive choice. Repetitive administration of hCRF probably caused tolerance of the cortisol response.

    View details for PubMedID 9834042

  • Dose-response function of epidural fentanyl versus sufentanil ANESTHESIA AND ANALGESIA Angst, M. S. 1998; 86 (4): 918-919

    View details for Web of Science ID 000072831700056

    View details for PubMedID 9539633

  • Dose-ranging study in younger adult and elderly patients of ORG 9487, a new, rapid-onset, short-duration muscle relaxant ANESTHESIA AND ANALGESIA Kahwaji, R., Bevan, D. R., Bikhazi, G., Shanks, C. A., Fragen, R. J., Dyck, J. B., Angst, M. S., Matteo, R. 1997; 84 (5): 1011-1018


    The purpose of this multicenter, randomized, assessorblind placebo-controlled study was to determine which of five doses of the new, rapid-onset neuromuscular relaxant, ORG 9487, provided both good to excellent tracheal intubating conditions 60 s after administration and a clinical duration of action < 20 min in 120 younger (aged 18-64 yr) and 61 elderly (aged 65-85 yr) adult patients. Anesthesia was induced with fentanyl (2-5 micrograms/kg) and thiopental (3-6 mg/kg) and maintained with N2O/O2 and a propofol infusion (50-300 Neuromuscular train-of-four (TOF) monitoring by electromyography (Datex Relaxograph) commenced immediately after anesthetic induction and was followed, within 30 s, by one of five doses of ORG 9487 (0.5, 1.0, 1.5, 2.0, 2.5 mg/kg) or a placebo. Tracheal intubation was attempted at 60 s and again, in the case of failure, at 90 s. Conditions were assessed with a 4-point scale. Maximum block, clinical duration (time to 25% T1 recovery), and recovery (TOF > or = 0.7) were measured. Dose-dependent changes were observed in tracheal intubating conditions and neuromuscular block. Good to excellent intubating conditions at 60 s were present in most younger adult (52 of 60) and elderly (26 of 31) patients administered doses > or = 1.5 mg/kg. Mean clinical durations < 20 min were observed in adult patients at doses up to 2.0 mg/kg and in geriatric patients up to 1.5 mg/kg. Thus, doses of 1.5-2.0 mg/kg ORG 9487 enabled both rapid tracheal intubation and a short clinical duration of action in adult and elderly patients.

    View details for Web of Science ID A1997WW54700012

    View details for PubMedID 9141923

  • A New Double-Lumen IV Infusion Set Reduces Pain on Injection of Propofol. J Clin Anesth Angst MS, Chris Tataru, Sean Mackey, Gary Zupfer, John B. Dyck, John G. Brock-Utne. 1997


    Previously, we reported elevated plasma immunoreactive ANP (irANP) levels from the 2nd to the 9th day of administering either prednisone, 50 mg/day, or 9 alpha-fludrocortisone acetate (9 alpha F), 0.6 mg/day, to normal humans. To investigate the course of plasma irANP levels during the first 48 h of corticosteroid administration, 9 healthy men (mean age +/- SEM, 24 +/- 1 years) received in randomised sequence A) a 4-h iv infusion of prednisolone sodium tetrahydrophthalate followed by oral administration of prednisone for 2 days; or B) a 4-h infusion of aldosterone followed by oral administration of 9 alpha F for 2 days. Basal supine plasma irANP levels averaged 32 +/- 5 ng/l in study A and 30 +/- 6 ng/l in study B; they were unchanged or even deceased up to 24 h of glucocorticoid or mineralocorticoid administration, but rose (P less than 0.01) to 56 +/- 9 and 62 +/- 12 ng/l at 48 h, respectively, of the two interventions. During glucocorticoid treatment, blood pressure (BP) and indices of the sodium-fluid volume state were unchanged after 48 h. During 9 alpha F administration, body weight increased (1.1 +/- 0.3%, P less than 0.001), whereas urinary sodium excretion (63 +/- 7%, P less than 0.001), hematocrit (4.1 +/- 1.1%, P less than 0.001), and plasma renin activity (38 +/- 4%, P less than 0.001) decreased. Conclusions: The increase in circulating irANP at 48 h of administration of either a glucocorticoid or a mineralocorticoid demonstrates a distinct but slow response of the ANP system to these corticosteroids in normal humans.(ABSTRACT TRUNCATED AT 250 WORDS)

    View details for Web of Science ID A1988N635200004

    View details for PubMedID 2968749