Dr. Amy Lo is a pathologist with board certification in anatomic pathology, clinical pathology and molecular genetic pathology. She completed her MD and MS at the University of Illinois at Chicago and her residency in both anatomic and clinical pathology at Northwestern University. She then joined the faculty at Northwestern University as a Clinical Instructor and Advanced Gastrointestinal/Surgical Pathology Fellow. Amy then completed a molecular genetic pathology fellowship at Stanford University.
In 2016, Amy joined Genentech as research pathology scientist supporting drug research and development with a focus in oncology and individualized drug development.
Additionally, Amy continues clinical work as an Adjunct Clinical Assistant Professor in pathology at Stanford University and Lucille Packard’s Children’s Hospital.
- Anatomic and Clinical Pathology
Fellowship: Stanford University Department of Pathology (2016) CA
Board Certification: American Board of Pathology, Molecular Genetic (2016)
Fellowship: Northwestern University Medical Center (2015) IL
Board Certification: American Board of Pathology, Anatomic and Clinical Pathology (2014)
Residency: Northwestern University Medical Center (2014) IL
Medical Education: University of Illinois at Chicago College of Medicine (2010) IL
T cell-dependent bispecific antibodies alter organ-specific endothelial cell-T cell interaction
Preclinical and clinical studies demonstrate that T cell-dependent bispecific antibodies (TDBs) induce systemic changes in addition to tumor killing, leading to adverse events. Here, we report an in-depth characterization of acute responses to TDBs in tumor-bearing mice. Contrary to modest changes in tumors, rapid and substantial lymphocyte accumulation and endothelial cell (EC) activation occur around large blood vessels in normal organs including the liver. We hypothesize that organ-specific ECs may account for the differential responses in normal tissues and tumors, and we identify a list of genes selectively upregulated by TDB in large liver vessels. Using one of the genes as an example, we demonstrate that CD9 facilitates ICAM-1 to support T cell-EC interaction in response to soluble factors released from a TDB-mediated cytotoxic reaction. Our results suggest that multiple factors may cooperatively promote T cell infiltration into normal organs as a secondary response to TDB-mediated tumor killing. These data shed light on how different vascular beds respond to cancer immunotherapy and may help improve their safety and efficacy.
View details for DOI 10.15252/embr.202255532
View details for Web of Science ID 000910517200001
View details for PubMedID 36621885
Origins and Timing of Emerging Lesions in Advanced Renal Cell Carcinoma.
Molecular cancer research : MCR
2022; 20 (6): 909-922
Renal cell carcinoma (RCC) with venous tumor thrombus (VTT) arising from the primary tumor occurs in approximately 10% of cases and is thought to represent more advanced disease. The intravascular nature of VTT suggests that it may serve as a source for hematogenous metastases. RCC with VTT and distant metastasis provides unique opportunities to examine the origins and emergence timing of these distinct tumor lesions, and to identify molecular correlates with disease state. We performed multi-region exome and RNA-sequencing analysis of 16 patients with RCC with VTT, with eight patients also having sequenced metastasis, to identify genomic alterations, biological pathways, and evolutionary processes contributing to VTT and metastasis, and to ask whether metastasis arises directly from or independent of VTT. No specific genomic alterations were associated with VTT. Hallmark copy-number alterations (deletions of 14q, 8p, and 4q) were associated with metastasis and disease recurrence, and secondary driver alterations tended to accumulate in metastatic lineages. Mismatch repair mutational signatures co-occurred across most tumors, suggesting a role for intracellular DNA damage in RCC. Robust phylogenetic timing analysis indicated that metastasis typically emerged before VTT, rather than deriving from it, with the earliest metastases predicted to emerge years before diagnosis. As a result, VTT in metastatic cases frequently derived from a metastatic lineage. Relative to the primary tumor, VTT upregulated immediate-early genes and transcriptional targets of the TNFα/NF-κB pathway, whereas metastases upregulated MTOR and transcriptional targets downstream of mTORC1 activation.These results suggest that VTT and metastasis formation occur independently, VTT presence alone does not necessarily imply more advanced disease with inevitably poor prognosis.
View details for DOI 10.1158/1541-7786.MCR-21-0590
View details for PubMedID 35297992
Novel Anti-LY6G6D/CD3 T Cell-Dependent Bispecific Antibody for the Treatment of Colorectal Cancer.
Molecular cancer therapeutics
New therapeutics and combination regimens have led to marked clinical improvements for the treatment of a subset of colorectal cancer (CRC). Immune checkpoint inhibitors have shown clinical efficacy in patients with mismatch repair-deficient or microsatellite instability-high (MSI-H) metastatic CRC (mCRC). However, patients with microsatellite-stable (MSS) or low levels of microsatellite instable (MSI-L) CRC have not benefited from these immune modulators, and the survival outcome remains poor for the majority of patients diagnosed with mCRC. In this report, we describe the discovery of a novel T cell-dependent bispecific antibody (TDB) targeting tumor-associated antigen LY6G6D for the treatment of CRC. Expression analyses reveal limited expression of LY6G6D in normal human tissues and non-CRC tumor types; meanwhile, significant LY6G6D upregulation in CRC is observed with high prevalence in MSS and MSI-L CRC subsets. The optimized anti-LY6G6D/CD3 TDB, which targets a membrane-proximal epitope of LY6G6D and binds to CD3 with high affinity, exhibits potent anti-tumor activity both in vitro and in vivo. In vitro functional assays show that LY6G6D-TDB-mediated T-cell activation and cytotoxicity are conditional and target-dependent. In mouse xenograft tumor models, LY6G6D-TDB demonstrates anti-tumor efficacy as a single agent against established CRC tumors, and enhanced efficacy can be achieved when LY6G6D-TDB is combined with PD-1 blockade. Our studies provide evidence for the therapeutic potential of anti-LY6G6D/CD3 TDB as an effective treatment option for patients with CRC.
View details for DOI 10.1158/1535-7163.MCT-21-0599
View details for PubMedID 35364611
Indication-specific tumor evolution and its impact on neoantigen targeting and biomarkers for individualized cancer immunotherapies
JOURNAL FOR IMMUNOTHERAPY OF CANCER
2021; 9 (10)
Individualized neoantigen-specific immunotherapy (iNeST) requires robustly expressed clonal neoantigens for efficacy, but tumor mutational heterogeneity, loss of neoantigen expression, and variable tissue sampling present challenges. It is assumed that clonal neoantigens are preferred targets for immunotherapy, but the distributions of clonal neoantigens are not well characterized across cancer types.We combined multiregion sequencing (MR-seq) analysis of five untreated, synchronously sampled metastatic solid tumors with re-analysis of published MR-seq data from 103 patients in order to characterize their globally clonal neoantigen content and factors that would impact neoantigen targeting.Branching evolution in colorectal cancer and renal cell carcinoma led to fewer clonal neoantigens and to clade-specific neoantigens (those shared across a subset of tumor regions but not fully clonal), with the latter not being readily distinguishable in single tumor samples. In colorectal, renal, and bladder cancer, most tumors had few globally clonal neoantigens. Prioritizing mutations with higher purity-adjusted and ploidy-adjusted variant allele frequency enriched for globally clonal neoantigens (those found in all tumor regions), whereas estimated cancer cell fraction derived from clustering-based tools, surprisingly, did not. Neoantigen quality was associated with loss of neoantigen expression in the bladder cancer case, and HLA-allele loss was observed in the renal and non-small cell lung cancer cases.We show that tumor type, multilesion sampling, neoantigen expression, and HLA allele retention are important factors for iNeST targeting and patient selection, and may also be important factors to consider in the development of biomarker strategies.
View details for DOI 10.1136/jitc-2021-003001
View details for Web of Science ID 000703621300011
View details for PubMedID 34599029
View details for PubMedCentralID PMC8488717
Single-cell dissection of cellular components and interactions shaping the tumor immune phenotypes in ovarian cancer
2021; 39 (7): 928-+
Distinct T cell infiltration patterns, i.e., immune infiltrated, excluded, and desert, result in different responses to cancer immunotherapies. However, the key determinants and biology underpinning these tumor immune phenotypes remain elusive. Here, we provide a high-resolution dissection of the entire tumor ecosystem through single-cell RNA-sequencing analysis of 15 ovarian tumors. Immune-desert tumors are characterized by unique tumor cell-intrinsic features, including metabolic pathways and low antigen presentation, and an enrichment of monocytes and immature macrophages. Immune-infiltrated and -excluded tumors differ markedly in their T cell composition and fibroblast subsets. Furthermore, our study reveals chemokine receptor-ligand interactions within and across compartments as potential mechanisms mediating immune cell infiltration, exemplified by the tumor cell-T cell cross talk via CXCL16-CXCR6 and stromal-immune cell cross talk via CXCL12/14-CXCR4. Our data highlight potential molecular mechanisms that shape the tumor immune phenotypes and may inform therapeutic strategies to improve clinical benefit from cancer immunotherapies.
View details for DOI 10.1016/j.ccell.2021.04.004
View details for Web of Science ID 000672680500012
View details for PubMedID 33961783
Cutaneous desmoid-type fibromatosis: a rare case with molecular profiling.
Journal of cutaneous pathology
Fibromatoses encompass a broad group of histopathologically similar fibroblastic/myofibroblastic proliferations with divergent clinical manifestations and behavior. Deep (desmoid-type) fibromatoses are typically large, rapidly growing, and locally aggressive tumors that occur in the abdominal wall, mesentery, and extraabdominal soft tissue, principally the musculature of the trunk and extremities. Most sporadic cases of desmoid fibromatosis harbor inactivating mutations in CTNNB1, the gene encoding beta-catenin. Tumors occurring in the context of familial adenomatous polyposis and Gardner syndrome bear inactivating mutations in APC. By contrast, mutations in CTNNB1 or APC have not been identified in cases of superficial fibromatosis. Cutaneous involvement by desmoid fibromatosis is exceedingly rare. Here we present a 78-year-old male with desmoid-type fibromatosis arising in the dermis of the right medial calf with a pathogenic mutation in CTNNB1 and a variant of unknown significance in APC. This article is protected by copyright. All rights reserved.
View details for DOI 10.1111/cup.14058
View details for PubMedID 33978242
Anti-LYPD1/CD3 T-Cell-Dependent Bispecific Antibody for the Treatment of Ovarian Cancer
MOLECULAR CANCER THERAPEUTICS
2021; 20 (4): 716-725
Ovarian cancer is a diverse class of tumors with very few effective treatment options and suboptimal response rates in early clinical studies using immunotherapies. Here we describe LY6/PLAUR domain containing 1 (LYPD1) as a novel target for therapeutic antibodies for the treatment of ovarian cancer. LYPD1 is broadly expressed in both primary and metastatic ovarian cancer with ∼70% prevalence in the serous cancer subset. Bispecific antibodies targeting CD3 on T cells and a tumor antigen on cancer cells have demonstrated significant clinical activity in hematologic cancers. We have developed an anti-LYPD1/CD3 T-cell-dependent bispecific antibody (TDB) to redirect T-cell responses to LYPD1 expressing ovarian cancer. Here we characterize the nonclinical pharmacology of anti-LYPD1/CD3 TDB and show induction of a robust polyclonal T-cell activation and target dependent killing of LYPD1 expressing ovarian cancer cells resulting in efficient in vivo antitumor responses in PBMC reconstituted immune-deficient mice and human CD3 transgenic mouse models. Anti-LYPD1/CD3 TDB is generally well tolerated at high-dose levels in mice, a pharmacologically relevant species, and showed no evidence of toxicity or damage to LYPD1 expressing tissues.
View details for DOI 10.1158/1535-7163.MCT-20-0490
View details for Web of Science ID 000636983400009
View details for PubMedID 33536191
Innovative Tumor Tissue Dissection Tool for Molecular Oncology Diagnostics
JOURNAL OF MOLECULAR DIAGNOSTICS
2021; 23 (4): 399-406
Formalin-fixed, paraffin-embedded (FFPE) tissue is the most commonly used material for tumor molecular profiling, therapy selection, and prognostication. Tumor tissue enrichment by tissue dissection is highly recommended to generate quality data reproducibly for use in downstream assays, such as real-time PCR and next-generation sequencing. The aim of this study was to evaluate the performance of the automated tissue dissection tool AVENIO Millisect System compared with a manual dissection method using 18 FFPE tissue specimens. The study assessed performance of these two methods with paraffinized and deparaffinized sections at 5- and 10-μm thickness as well as at low (5% to 10%) and high (>50%) tumor content. In addition, compatibility with various nucleic acid and protein extraction methods was assessed. Overall, dissection by Millisect resulted in statistically significantly higher yields of nucleic acids and protein compared with manual dissection (P = 0.00524). In downstream analysis on a statistically nonpowered sample set, EGFR mutation testing by PCR led to highly concordant results, and next-generation sequencing testing yielded significantly higher allelic frequencies when tissue was dissected by Millisect compared with manual scraping, demonstrating noninferiority of the automated method. In summary, the AVENIO Millisect System may replace manual labor and support automation of FFPE tumor tissue workflows in clinical molecular laboratories with high testing volumes with adequate validation.
View details for DOI 10.1016/j.jmoldx.2021.01.006
View details for Web of Science ID 000631679100003
View details for PubMedID 33497835
Automated Dissection Protocol for Tumor Enrichment in Low Tumor Content Tissues
JOVE-JOURNAL OF VISUALIZED EXPERIMENTS
Tumor enrichment in low tumor content tissues, those below 20% tumor content depending on the method, is required to generate quality data reproducibly with many downstream assays such as next generation sequencing. Automated tissue dissection is a new methodology that automates and improves tumor enrichment in these common, low tumor content tissues by decreasing the user-dependent imprecision of traditional macro-dissection and time, cost, and expertise limitations of laser capture microdissection by using digital image annotation overlay onto unstained slides. Here, digital hematoxylin and eosin (H&E) annotations are used to target small tumor areas using a blade that is 250 µm2 in diameter in unstained formalin fixed paraffin embedded (FFPE) or fresh frozen sections up to 20 µm in thickness for automated tumor enrichment prior to nucleic acid extraction and whole exome sequencing (WES). Automated dissection can harvest annotated regions in low tumor content tissues from single or multiple sections for nucleic acid extraction. It also allows for capture of extensive pre- and post-harvest collection metrics while improving accuracy, reproducibility, and increasing throughput with utilization of fewer slides. The described protocol enables digital annotation with automated dissection on animal and/or human FFPE or fresh frozen tissues with low tumor content and could also be used for any region of interest enrichment to boost adequacy for downstream sequencing applications in clinical or research workflows.
View details for DOI 10.3791/62394
View details for Web of Science ID 000646200200087
View details for PubMedID 33843927
Multi-region sequencing analysis of metastatic solid tumors to inform targeting of personalized cancer immunotherapies.
AMER ASSOC CANCER RESEARCH. 2021
View details for Web of Science ID 000618215800095
Report on computational assessment of Tumor Infiltrating Lymphocytes from the International Immuno-Oncology Biomarker Working Group.
NPJ breast cancer
2020; 6 (1): 16
Assessment of tumor-infiltrating lymphocytes (TILs) is increasingly recognized as an integral part of the prognostic workflow in triple-negative (TNBC) and HER2-positive breast cancer, as well as many other solid tumors. This recognition has come about thanks to standardized visual reporting guidelines, which helped to reduce inter-reader variability. Now, there are ripe opportunities to employ computational methods that extract spatio-morphologic predictive features, enabling computer-aided diagnostics. We detail the benefits of computational TILs assessment, the readiness of TILs scoring for computational assessment, and outline considerations for overcoming key barriers to clinical translation in this arena. Specifically, we discuss: 1. ensuring computational workflows closely capture visual guidelines and standards; 2. challenges and thoughts standards for assessment of algorithms including training, preanalytical, analytical, and clinical validation; 3. perspectives on how to realize the potential of machine learning models and to overcome the perceptual and practical limits of visual scoring.
View details for DOI 10.1038/s41523-020-0154-2
View details for PubMedID 33574288
Powerful Multi-Region Sequencing and Somatic Mutation Clonality Analysis of Intratumoral Heterogeneity on Paired Primary and Metastatic Tumor Samples
NATURE PUBLISHING GROUP. 2020: 1703-1704
View details for Web of Science ID 000518328803502
Millisect Automated Tissue Dissection: A Novel and Efficient Tool for Selected Tissue Sequencing
SPRINGERNATURE. 2020: 1698-1699
View details for Web of Science ID 000518328903496
- Automated tissue dissection of dermal lymphatic emboli in inflammatory breast cancer enhances accuracy of transcriptional analysis AMER ASSOC CANCER RESEARCH. 2020
Pitfalls in assessing stromal tumor infiltrating lymphocytes (sTILs) in breast cancer.
NPJ breast cancer
2020; 6: 17
Stromal tumor-infiltrating lymphocytes (sTILs) are important prognostic and predictive biomarkers in triple-negative (TNBC) and HER2-positive breast cancer. Incorporating sTILs into clinical practice necessitates reproducible assessment. Previously developed standardized scoring guidelines have been widely embraced by the clinical and research communities. We evaluated sources of variability in sTIL assessment by pathologists in three previous sTIL ring studies. We identify common challenges and evaluate impact of discrepancies on outcome estimates in early TNBC using a newly-developed prognostic tool. Discordant sTIL assessment is driven by heterogeneity in lymphocyte distribution. Additional factors include: technical slide-related issues; scoring outside the tumor boundary; tumors with minimal assessable stroma; including lymphocytes associated with other structures; and including other inflammatory cells. Small variations in sTIL assessment modestly alter risk estimation in early TNBC but have the potential to affect treatment selection if cutpoints are employed. Scoring and averaging multiple areas, as well as use of reference images, improve consistency of sTIL evaluation. Moreover, to assist in avoiding the pitfalls identified in this analysis, we developed an educational resource available at www.tilsinbreastcancer.org/pitfalls.
View details for DOI 10.1038/s41523-020-0156-0
View details for PubMedID 32411819
View details for PubMedCentralID PMC7217863
- Integrated digital pathology and transcriptome analysis identifies molecular mediators of T cell exclusion in ovarian cancer AMER ASSOC CANCER RESEARCH. 2019
- Complete and Prolonged Response to Immune Checkpoint Blockade in POLE-Mutated Colorectal Cancer JCO PRECISION ONCOLOGY 2019; 3: 1–5
Avidity-based binding to HER2 results in selective killing of HER2-overexpressing cells by anti-HER2/CD3
SCIENCE TRANSLATIONAL MEDICINE
2018; 10 (463)
A primary barrier to the success of T cell-recruiting bispecific antibodies in the treatment of solid tumors is the lack of tumor-specific targets, resulting in on-target off-tumor adverse effects from T cell autoreactivity to target-expressing organs. To overcome this, we developed an anti-HER2/CD3 T cell-dependent bispecific (TDB) antibody that selectively targets HER2-overexpressing tumor cells with high potency, while sparing cells that express low amounts of HER2 found in normal human tissues. Selectivity is based on the avidity of two low-affinity anti-HER2 Fab arms to high target density on HER2-overexpressing cells. The increased selectivity to HER2-overexpressing cells is expected to mitigate the risk of adverse effects and increase the therapeutic index. Results included in this manuscript not only support the clinical development of anti-HER2/CD3 1Fab-immunoglobulin G TDB but also introduce a potentially widely applicable strategy for other T cell-directed therapies. The potential of this discovery has broad applications to further enable consideration of solid tumor targets that were previously limited by on-target, but off-tumor, autoimmunity.
View details for DOI 10.1126/scitranslmed.aat5775
View details for Web of Science ID 000448832800003
View details for PubMedID 30333240
Relative Target Affinities of T-Cell-Dependent Bispecific Antibodies Determine Biodistribution in a Solid Tumor Mouse Model
MOLECULAR CANCER THERAPEUTICS
2018; 17 (4): 776-785
Anti-HER2/CD3, a T-cell-dependent bispecific antibody (TDB) construct, induces T-cell-mediated cell death in cancer cells expressing HER2 by cross-linking tumor HER2 with CD3 on cytotoxic T cells, thereby creating a functional cytolytic synapse. TDB design is a very challenging process that requires consideration of multiple parameters. Although therapeutic antibody design strategy is commonly driven by striving for the highest attainable antigen-binding affinity, little is known about how the affinity of each TDB arm can affect the targeting ability of the other arm and the consequent distribution and efficacy. To our knowledge, no distribution studies have been published using preclinical models wherein the T-cell-targeting arm of the TDB is actively bound to T cells. We used a combined approach involving radiochemistry, invasive biodistribution, and noninvasive single-photon emission tomographic (SPECT) imaging to measure TDB distribution and catabolism in transgenic mice with human CD3ε expression on T cells. Using CD3 affinity variants, we assessed the impact of CD3 affinity on short-term pharmacokinetics, tissue distribution, and cellular uptake. Our experimental approach determined the relative effects of (i) CD3 targeting to normal tissues, (ii) HER2 targeting to HER2-expressing tumors, and (iii) relative HER2/CD3 affinity, all as critical drivers for TDB distribution. We observed a strong correlation between CD3 affinity and distribution to T-cell-rich tissues, with higher CD3 affinity reducing systemic exposure and shifting TDB distribution away from tumor to T-cell-containing tissues. These observations have important implications for clinical translation of bispecific antibodies for cancer immunotherapy. Mol Cancer Ther; 17(4); 776-85. ©2018 AACR.
View details for DOI 10.1158/1535-7163.MCT-17-0657
View details for Web of Science ID 000429111900007
View details for PubMedID 29339550
Assessing Tumor-Infiltrating Lymphocytes in Solid Tumors: A Practical Review for Pathologists and Proposal for a Standardized Method from the International Immuno-Oncology Biomarkers Working Group: Part 2: TILs in Melanoma, Gastrointestinal Tract Carcinomas, Non-Small Cell Lung Carcinoma and Mesothelioma, Endometrial and Ovarian Carcinomas, Squamous Cell Carcinoma of the Head and Neck, Genitourinary Carcinomas, and Primary Brain Tumors
ADVANCES IN ANATOMIC PATHOLOGY
2017; 24 (6): 311–35
Assessment of the immune response to tumors is growing in importance as the prognostic implications of this response are increasingly recognized, and as immunotherapies are evaluated and implemented in different tumor types. However, many different approaches can be used to assess and describe the immune response, which limits efforts at implementation as a routine clinical biomarker. In part 1 of this review, we have proposed a standardized methodology to assess tumor-infiltrating lymphocytes (TILs) in solid tumors, based on the International Immuno-Oncology Biomarkers Working Group guidelines for invasive breast carcinoma. In part 2 of this review, we discuss the available evidence for the prognostic and predictive value of TILs in common solid tumors, including carcinomas of the lung, gastrointestinal tract, genitourinary system, gynecologic system, and head and neck, as well as primary brain tumors, mesothelioma and melanoma. The particularities and different emphases in TIL assessment in different tumor types are discussed. The standardized methodology we propose can be adapted to different tumor types and may be used as a standard against which other approaches can be compared. Standardization of TIL assessment will help clinicians, researchers and pathologists to conclusively evaluate the utility of this simple biomarker in the current era of immunotherapy.
View details for PubMedID 28777143
Assessing Tumor-infiltrating Lymphocytes in Solid Tumors: A Practical Review for Pathologists and Proposal for a Standardized Method From the International Immunooncology Biomarkers Working Group: Part 1: Assessing the Host Immune Response, TILs in Invasive Breast Carcinoma and Ductal Carcinoma In Situ, Metastatic Tumor Deposits and Areas for Further Research
ADVANCES IN ANATOMIC PATHOLOGY
2017; 24 (5): 235–51
Assessment of tumor-infiltrating lymphocytes (TILs) in histopathologic specimens can provide important prognostic information in diverse solid tumor types, and may also be of value in predicting response to treatments. However, implementation as a routine clinical biomarker has not yet been achieved. As successful use of immune checkpoint inhibitors and other forms of immunotherapy become a clinical reality, the need for widely applicable, accessible, and reliable immunooncology biomarkers is clear. In part 1 of this review we briefly discuss the host immune response to tumors and different approaches to TIL assessment. We propose a standardized methodology to assess TILs in solid tumors on hematoxylin and eosin sections, in both primary and metastatic settings, based on the International Immuno-Oncology Biomarker Working Group guidelines for TIL assessment in invasive breast carcinoma. A review of the literature regarding the value of TIL assessment in different solid tumor types follows in part 2. The method we propose is reproducible, affordable, easily applied, and has demonstrated prognostic and predictive significance in invasive breast carcinoma. This standardized methodology may be used as a reference against which other methods are compared, and should be evaluated for clinical validity and utility. Standardization of TIL assessment will help to improve consistency and reproducibility in this field, enrich both the quality and quantity of comparable evidence, and help to thoroughly evaluate the utility of TILs assessment in this era of immunotherapy.
View details for PubMedID 28777142
HKDC1 Is a Novel Hexokinase Involved in Whole-Body Glucose Use
2016; 157 (9): 3452-3461
In a recent genome-wide association study, hexokinase domain-containing protein 1, or HKDC1, was found to be associated with gestational glucose levels during 2-hour glucose tolerance tests at 28 weeks of pregnancy. Because our understanding of the mediators of gestational glucose homeostasis is incomplete, we have generated the first transgenic mouse model to begin to understand the role of HKDC1 in whole-body glucose homeostasis. Interestingly, deletion of both HKDC1 alleles results in in utero embryonic lethality. Thus, in this study, we report the in vivo role of HKDC1 in whole-body glucose homeostasis using a heterozygous-deleted HKDC1 mouse model (HKDC1(+/-)) as compared with matched wild-type mice. First, we observed no weight, fasting or random glucose, or fasting insulin abnormalities with aging in male and female HKDC1(+/-) mice. However, during glucose tolerance tests, glucose levels were impaired in both female and male HKDC1(+/-) mice at 15, 30, and 120 minutes at a later age (28 wk of age). These glucose tolerance differences also existed in the female HKDC1(+/-) mice at earlier ages but only during pregnancy. And finally, the impaired glucose tolerance in HKDC1(+/-) mice was likely due to diminished whole-body glucose use, as indicated by the decreased hepatic energy storage and reduced peripheral tissue uptake of glucose in HKDC1(+/-) mice. Collectively, these data highlight that HKDC1 is needed to maintain whole-body glucose homeostasis during pregnancy but also with aging, possibly through its role in glucose use.
View details for DOI 10.1210/en.2016-1288
View details for Web of Science ID 000384132900021
View details for PubMedID 27459389
View details for PubMedCentralID PMC5007896
Adverse events after surgery for nonmalignant colon polyps are common and associated with increased length of stay and costs
2016; 84 (2): 296-+
Endoscopic resection (ER) is a safe and effective treatment for nonmalignant complex colorectal polyps (complex polyps). Surgical resection (SR) remains prevalent despite limited outcomes data. We aimed to evaluate SR outcomes for complex polyps and compare SR outcomes to those of ER.We performed a single-center, retrospective, cohort study of all patients undergoing SR (2003-2013) and ER (2011-2013) for complex polyps. We excluded patients with invasive carcinoma from the SR cohort. Primary outcomes were 12-month adverse event (AE) rate, length of stay (LOS), and costs. SR outcomes over a 3-year period (2011-2013) were compared with the overlapping ER cohort.Over the 11-year period, 359 patients (mean [± SD] age 64 ± 11 years) underwent SR (58% laparoscopic) for complex polyps. In total, 17% experienced an AE, and 3% required additional surgery; 12-month mortality was 1%. Including readmissions, median LOS was 5 days (IQR 4-7 days), and costs were $14,528. When an AE occurred, costs ($25,557 vs $14,029; P < .0001) and LOS (11 vs 5 days; P < .0001) significantly increased. From 2011 to 2013, 198 patients were referred for ER, and 73 underwent primary SR (70% laparoscopic). There was a lower AE rate for ER versus primary SR (10% vs 18%; P = .09). ER costs (including rescue SR, when required) were lower than those of primary SR ($2152 vs $15,264; P < .0001).AEs occur in approximately one-sixth of patients after SR for complex polyps. ER-accounting for rescue SR caused by malignancy, AEs, or incomplete resection-is associated with markedly lower costs than SR. These data should be used when counseling patients about treatment options for complex polyps.
View details for DOI 10.1016/j.gie.2016.01.048
View details for Web of Science ID 000381913200014
View details for PubMedID 26828760
Dapagliflozin-Induced Acute-on-Chronic Liver Injury
ACG CASE REPORTS JOURNAL
2016; 3 (4): e169
Sodium-glucose cotransporter 2 inhibitors are a new class of oral hypoglycemic agents, and thus safety data are limited. We present a 48-year-old woman with type 2 diabetes mellitus and Child's Class A cirrhosis secondary to nonalcoholic steatohepatitis presenting with jaundice and acute cholestatic liver injury. Other than starting dapagliflozin, she reported no medication changes or supplement use. Before treatment, her total bilirubin was 1.2 mg/dL. On admission, her liver values were elevated and liver biopsy was consistent with drug-induced liver injury. This report raises awareness about the potential hepatotoxic effects of dapagliflozin, particularly in patients with chronic liver disease.
View details for DOI 10.14309/crj.2016.142
View details for Web of Science ID 000394566000112
View details for PubMedID 28008402
View details for PubMedCentralID PMC5171930
Primary Adenocarcinoma of an Ileostomy in Crohn's Disease.
ACG case reports journal
2016; 3 (4)
Although Crohn's disease has been associated with an increased risk of small bowel adenocarcinoma, primary adenocarcinoma arising from an ileostomy is a complication that has been rarely documented in Crohn's disease. Chronic small bowel inflammation may lead to development of malignancy through the dysplasia-carcinoma sequence. We report a case of a 61-year-old woman with Crohn's ileocolitis diagnosed with a primary adenocarcinoma at the ileostomy with metastases to the liver 47 years after proctocolectomy, and review the literature.
View details for DOI 10.14309/crj.2016.85
View details for PubMedID 27622191
View details for PubMedCentralID PMC5018220
- Endoscopic Resection versus Surgical Resection of Complex Colon Polyps: The Costs and Adverse Events Associated With Competing Management Strategies MOSBY-ELSEVIER. 2016: AB119-AB120
- Histopathologic patterns among achalasia subtypes Response NEUROGASTROENTEROLOGY AND MOTILITY 2016; 28 (4): 609
Composite Epstein-Barr Virus-Associated B-Cell Lymphoproliferative Disorder and Tubular Adenoma in a Rectal Polyp
INTERNATIONAL JOURNAL OF SURGICAL PATHOLOGY
2016; 24 (1): 73-77
Composite tumors are formed when there is intermingling between two components of separate tumors seen histologically. Cases demonstrating composite tubular adenoma with other types of tumors in the colon are rare. Composite tubular adenomas with nonlymphoid tumors including carcinoids, microcarcinoids, and small cell undifferentiated carcinoma have been reported in the literature. The occurrence of composite lymphoma and tubular adenoma within the colorectal tract is extremely rare. Only three cases have been reported and include one case of mantle cell lymphoma and two cases of diffuse large B-cell lymphoma arising in composite tubular adenomas. We present the first case of composite Epstein-Barr virus-associated B-cell lymphoproliferative disorder and tubular adenoma in a rectal polyp with a benign endoscopic appearance.
View details for DOI 10.1177/1066896915604736
View details for Web of Science ID 000368936800015
View details for PubMedID 26353852
Comparative Study of Isocitrate Dehydrogenase 1 Mutations in Intraheptatic Cholangiocarcinoma by Immunohistochemistry and Pyrosequencing
NATURE PUBLISHING GROUP. 2016: 443A–444A
View details for Web of Science ID 000369270702496
Somatic Mutational Landscape of Inflammatory Bowel Disease-Associated Signet Ring Cell Colorectal Carcinoma
NATURE PUBLISHING GROUP. 2016: 456A
View details for Web of Science ID 000369270702545
Histopathologic patterns among achalasia subtypes
NEUROGASTROENTEROLOGY AND MOTILITY
2016; 28 (1): 139-145
Achalasia has three distinct manometric phenotypes. This study aimed to determine if there were corresponding histopathologic patterns.We retrospectively examined surgical muscularis propria biopsies obtained from 46 patients during laparoscopic esophagomyotomy. Pre-operative (conventional) manometry tracings were reviewed by two expert gastroenterologists who categorized patients into Chicago Classification subtypes. Pathology specimens were graded on degree of neuronal loss, inflammation, fibrosis, and muscle changes.Manometry studies were categorized as follows: type I (n = 20), type II (n = 20), type III (n = 3), and esophagogastric junction outflow obstruction (EGJOO) (n = 3). On histopathology, complete ganglion cell loss occurred in 74% of specimens, inflammation in 17%, fibrosis in 11%, and muscle atrophy in 2%. Comparing type I and type II specimens, there was a statistically significant greater proportion of type I specimens with aganglionosis (19/20 vs 13/20, p = 0.044) and a statistically significant greater degree of ganglion cell loss in type I specimens (Wilcoxon Rank-Sum, p = 0.016). CD3(+) /CD8(+) cytotoxic T cells represented the predominant inflammatory infiltrate on immunohistochemistry. Three patients had completely normal appearing tissue (1 each in type II, type III, EGJOO).The greater degree, but similar pattern, of ganglion cell loss observed in type I compared to type II achalasia specimens suggests that type I achalasia represents a progression from type II achalasia. The spectrum of histopathologic findings - from complete neuronal loss to lymphocytic inflammation to apparently normal histopathology - emphasizes that 'achalasia' represents a pathogenically heterogeneous patient group with the commonality being EGJ outflow obstruction.
View details for DOI 10.1111/nmo.12711
View details for Web of Science ID 000367019100014
View details for PubMedID 26542087
View details for PubMedCentralID PMC4688144
Beyond hepatic hemangiomas: the diverse appearances of gastrointestinal and genitourinary hemangiomas
2015; 40 (8): 3313-3329
Hemangiomas are common lesions, best known for their appearance in the liver. Their appearance in less common locations, such as the gastrointestinal and genitourinary tracts, is less well known. We will review the typical and atypical appearance of hemangiomas in these locations on sonography, CT, and MRI.
View details for DOI 10.1007/s00261-015-0515-8
View details for Web of Science ID 000363952000043
View details for PubMedID 26239397
Isolated Gallbladder Intramucosal Metastatic Melanoma With Features Mimicking Lymphoepithelial Carcinoma
INTERNATIONAL JOURNAL OF SURGICAL PATHOLOGY
2015; 23 (5): 409-413
Malignant melanoma has a variety of morphologic patterns and can metastasize and mimic any type of neoplastic process creating significant diagnostic difficulty. When metastasis to the gastrointestinal system is identified, it is most commonly associated with widely metastatic disease. We report a rare case of isolated gallbladder intramucosal metastatic melanoma with features mimicking lymphoepithelial carcinoma in an adult patient who presented with cholecystitis. Additionally, we report the imaging and morphologic features and discuss the importance of these findings along with a clear clinical history and immunohistochemical profile to make a definitive diagnosis.
View details for DOI 10.1177/1066896915588932
View details for Web of Science ID 000357927700015
View details for PubMedID 26041740
Concurrent Acute Necrotizing Adenovirus Hepatitis and Enterocolitis in an Adult Patient After Double Cord Blood Stem Cell Transplant for Refractory Crohn's Disease
INTERNATIONAL JOURNAL OF SURGICAL PATHOLOGY
2015; 23 (5): 404-408
It has been recently recognized that adenovirus is a pathogen with high morbidity and mortality among immunocompromised patients, particularly after solid organ or stem cell transplant. Confluent necrotizing hepatitis secondary to adenovirus infection alone or together with other organ involvement is extremely rare. There are only 32 cases of confluent necrotizing hepatitis reported in adults since 1960 and most occur after iatrogenic immunosuppression for bone marrow or solid organ transplantation or in other states of immunosuppression, including acquired immunodeficiency syndrome or chemotherapy treatment. We present the first case of concurrent adenovirus-induced necrotizing hepatitis and enterocolitis in an adult patient after double cord stem cell transplant for refractory Crohn's disease. Additionally, we report the imaging and morphologic findings and discuss the potential significance of morphology and immunohistochemistry as a practical approach for identifying adenovirus.
View details for DOI 10.1177/1066896915587758
View details for Web of Science ID 000357927700014
View details for PubMedID 25998316
- Outcomes of Surgical Resection for Benign Colorectal Neoplasms: an Analysis of 359 Resections At a Single Academic Medical Center MOSBY-ELSEVIER. 2015: AB283-AB284
Unique morphologic and clinical features of liver predominant/primary small cell carcinoma-autopsy and biopsy case series
ANNALS OF DIAGNOSTIC PATHOLOGY
2014; 18 (3): 151-156
Liver predominant small cell carcinoma is rare but often presents as hyperacute liver failure with unknown primary and is a medical emergency. We present 2 autopsy and 7 biopsy cases of liver predominant small cell carcinoma and demonstrate that these patients present with liver failure and identifiable hepatomegaly but lack discrete lesions on imaging as well as no mass lesions identified in other organs including lung. Compared with the multiple nodules of metastatic small cell carcinoma in the liver, unique morphologic feature of liver predominant/primary small cell carcinoma in autopsy and biopsy specimens was a diffuse infiltration of small blue neoplastic cells predominantly in the sinusoidal space in the liver parenchyma. Before diagnosing liver predominant/primary small cell carcinoma, other infiltrating small blue cell neoplasms including lymphoma and peripheral neuroectodermal tumor need to be ruled out through immunohistochemistry. We, therefore, demonstrate that liver biopsy together with a rapid panel of immunostains is necessary to firmly establish a diagnosis of liver predominant small cell carcinoma and allow clinicians to immediately implement potentially lifesaving chemotherapy.
View details for DOI 10.1016/j.anndiagpath.2014.02.007
View details for Web of Science ID 000336639400007
View details for PubMedID 24667053
View details for PubMedCentralID PMC4065801
Fine-needle aspiration of the liver
Differential Diagnosis in Cytopathology
View details for DOI 10.1017/CBO9781139628822.016
Lymphoid Proliferations Associated With Human Immunodeficiency Virus Infection
ARCHIVES OF PATHOLOGY & LABORATORY MEDICINE
2013; 137 (3): 360-370
Individuals who are immune deficient are at an increased risk for developing lymphoproliferative lesions and lymphomas. Human immunodeficiency virus (HIV) infection is 1 of 4 clinical settings associated with immunodeficiency recognized by the World Health Organization (WHO) in which there is an increased incidence of lymphoma and other lymphoproliferative disorders.To describe the major categories of benign lymphoid proliferations, including progressive HIV-related lymphadenopathy, benign lymphoepithelial cystic lesions, and multicentric Castleman disease, as well as the different types of HIV-related lymphomas as defined by the WHO. The characteristic morphologic, immunophenotypic, and genetic features of the different entities will be discussed in addition to some of the pathogenetic mechanisms.The WHO classification of tumors of hematopoietic and lymphoid tissues (2001 and 2008), published literature from PubMed (National Library of Medicine), published textbooks, and primary material from the authors' current and previous institutions.HIV infection represents one of the clinical settings recognized by the WHO in which immunodeficiency-related lymphoproliferative disorders may arise. Although most lymphomas that arise in patients with HIV infection are diffuse, aggressive B-cell lesions, other lesions, which are "benign" lymphoid proliferations, may also be associated with significant clinical consequences. These lymphoproliferations, like many other immunodeficiency-associated lymphoproliferative disorders, are often difficult to classify. Studies of HIV-associated lymphoid proliferations will continue to increase our understanding of both the immune system and lymphomagenesis.
View details for DOI 10.5858/arpa.2012-0095-RA
View details for Web of Science ID 000319776700010
View details for PubMedID 23451747
Intrauterine Fetal Death of a Monochorionic Twin with Peripheral Pulmonary Infarcts: Potential Thromboembolic Events Following Death of Co-Twin
PEDIATRIC AND DEVELOPMENTAL PATHOLOGY
2012; 15 (2): 142-145
In utero fetal lung infarction has rarely been reported. We present a case of intrauterine lung infarction in a 28-3/7 weeks' gestation monochorionic twin following intrauterine fetal demise of the co-twin at 20 weeks. This case highlights the potential for thromboembolic events (TBEs) associated with monochorionic gestations to include pulmonary TBE and infarction among the risks for fetal morbidity and mortality.
View details for DOI 10.2350/11-07-1056-CR.1
View details for Web of Science ID 000308802900010
View details for PubMedID 22070756
- Primary Effusion Lymphoma/Extracavitary Effusion Lymphoma: A Virus-Associated Lymphoma AJSP-REVIEWS AND REPORTS 2012; 17 (2): 69-74
Leptin Promotes Fibroproliferative Acute Respiratory Distress Syndrome by Inhibiting Peroxisome Proliferator-activated Receptor-gamma
AMERICAN JOURNAL OF RESPIRATORY AND CRITICAL CARE MEDICINE
2011; 183 (11): 1490-1498
Diabetic patients have a lower incidence of acute respiratory distress syndrome (ARDS), and those who develop ARDS are less likely to die. The mechanisms that underlie this protection are unknown.To determine whether leptin resistance, a feature of diabetes, prevents fibroproliferation after lung injury.We examined lung injury and fibroproliferation after the intratracheal instillation of bleomycin in wild-type and leptin-resistant (db/db) diabetic mice. We examined the effect of leptin on transforming growth factor (TGF)-β(1)-mediated transcription in primary normal human lung fibroblasts. Bronchoalveolar lavage fluid (BAL) samples from patients with ARDS and ventilated control subjects were obtained for measurement of leptin and active TGF-β(1) levels.Diabetic mice (db/db) were resistant to lung fibrosis. The db/db mice had higher levels of peroxisome proliferator-activated receptor-γ (PPARγ), an inhibitor of the transcriptional response to TGF-β(1), a cytokine critical in the pathogenesis of fibroproliferative ARDS. In normal human lung fibroblasts, leptin augmented the transcription of profibrotic genes in response to TGF-β(1) through a mechanism that required PPARγ. In patients with ARDS, BAL leptin levels were elevated and correlated with TGF-β(1) levels. Overall, there was no significant relationship between BAL leptin levels and clinical outcomes; however, in nonobese patients, higher BAL leptin levels were associated with fewer intensive care unit- and ventilator-free days and higher mortality.Leptin signaling is required for bleomycin-induced lung fibrosis. Leptin augments TGF-β(1) signaling in lung fibroblasts by inhibiting PPARγ. These findings provide a mechanism for the observed protection against ARDS observed in diabetic patients.
View details for DOI 10.1164/rccm.201009-1409OC
View details for Web of Science ID 000291647200013
View details for PubMedID 21317313
View details for PubMedCentralID PMC3266063
Enteropathogenic E. coli non-LEE encoded effectors NleH1 and NleH2 attenuate NF-kappa B activation
2010; 78 (5): 1232-1245
Enteric bacterial pathogens have evolved sophisticated strategies to evade host immune defences. Some pathogens deliver anti-inflammatory effector molecules into the host cell cytoplasm via a type III secretion system (T3SS). Enteropathogenic Escherichia coli (EPEC) inhibits inflammation by an undefined, T3SS-dependent mechanism. Two proteins encoded outside of the EPEC locus of enterocyte effacement (LEE) pathogenicity island, non-LEE-encoded effector H1 (NleH1) and H2 (NleH2), display sequence similarity to Shigella flexneri OspG, which inhibits activation of the pro-inflammatory transcription factor NF-κB. We hypothesized that the anti-inflammatory effects of EPEC were mediated by NleH1 and NleH2. In this study, we examined the effect of NleH1/H2 on the NF-κB pathway. We show that NleH1/H2 are secreted via the T3SS and that transfection of cells with plasmids harbouring nleH1 or nleH2 decreased IKK-β-induced NF-κB activity and attenuated TNF-α-induced degradation of phospho-IκBα by preventing ubiquitination. Serum KC levels were higher in mice infected with ΔnleH1H2 than those infected with WT EPEC, indicating that NleH1/H2 dampen pro-inflammatory cytokine expression. ΔnleH1H2 was cleared more rapidly than WT EPEC while complementation of ΔnleH1H2 with either NleH1 or NleH2 prolonged colonization. Together, these data show that NleH1 and NleH2 function to dampen host inflammation and facilitate EPEC colonization during pathogenesis.
View details for DOI 10.1111/j.1365-2958.2010.07400.x
View details for Web of Science ID 000284484500014
View details for PubMedID 21091507
View details for PubMedCentralID PMC3325542
Enterohemorrhagic E. coli alters murine intestinal epithelial tight junction protein expression and barrier function in a Shiga toxin independent manner
2010; 90 (8): 1152-1168
Shiga toxin (Stx) is implicated in the development of hemorrhagic colitis and hemolytic-uremic syndrome, but early symptoms of enterohemorrhagic Escherichia coli (EHEC) infection such as nonbloody diarrhea may be Stx independent. In this study, we defined the effects of EHEC, in the absence of Stx, on the intestinal epithelium using a murine model. EHEC colonization of intestines from two groups of antibiotic-free and streptomycin-treated C57Bl/6J mice were characterized and compared. EHEC colonized the cecum and colon more efficiently than the ileum in both groups; however, greater amounts of tissue-associated EHEC were detected in streptomycin-pretreated mice. Imaging of intestinal tissues of mice infected with bioluminescent EHEC further confirmed tight association of the bacteria with the cecum and colon. Greater numbers of EHEC were also cultured from stool samples obtained from streptomycin-pretreated mice, as compared with those that received no antibiotics. Transmission electron microscopy shows that EHEC infection leads to microvillous effacement of mouse colonocytes. Hematoxylin and eosin staining of the colonic tissues of infected mice revealed a slight increase in the number of lamina propria polymorphonuclear leukocytes. Transmucosal electrical resistance, a measure of epithelial barrier function, was reduced in the colonic tissues of infected animals. Increased mucosal permeability to 4- kDa FITC-dextran was also observed in the colonic tissues of infected mice. Immunofluorescence microscopy showed that EHEC infection resulted in redistribution of the tight junction (TJ) proteins occludin and claudin-3 and increased the expression of claudin-2, whereas ZO-1 localization remained unaltered. Quantitative real-time PCR showed that EHEC altered mRNA transcription of OCLN, CLDN2, and CLDN3. Most notably, claudin-2 expression was significantly increased and correlated with increased intestinal permeability. Our data indicate that C57Bl/6J mice serve as an in vivo model to study the physiological effects of EHEC infection on the intestinal epithelium and suggest that altered transcription of TJ proteins has a role in the increase in intestinal permeability.
View details for DOI 10.1038/labinvest.2010.91
View details for Web of Science ID 000280549600003
View details for PubMedID 20479715
View details for PubMedCentralID PMC2912457
Enterohemorrhagic Escherichia coli suppresses inflammatory response to cytokines and its own toxin
AMERICAN JOURNAL OF PHYSIOLOGY-GASTROINTESTINAL AND LIVER PHYSIOLOGY
2009; 297 (3): G576-G581
Infection with the enteric pathogen enterohemorrhagic Escherichia coli (EHEC) causes a variety of symptoms ranging from nonbloody diarrhea to more severe sequelae including hemorrhagic colitis, altered sensorium and seizures, and even life-threatening complications, such as hemolytic uremic syndrome and thrombotic thrombocytopenic purpura. The more severe consequences of EHEC infection are attributable to the production of Shiga toxin (Stx) and its subsequent effects on the vasculature, which expresses high levels of the Stx receptor, Gb3. Interestingly, the intestinal epithelium does not express Gb3. Despite the lack of Gb3 receptor expression, intestinal epithelial cells translocate Stx. The effect of Stx on intestinal epithelial cells is controversial with some studies demonstrating induction of inflammation and others not. This may be difficult to resolve because EHEC expresses both proinflammatory molecules, such as flagellin, and factor(s) that dampen the inflammatory response of epithelial cells. The goal of our study was to define the effect of Stx on the inflammatory response of intestinal epithelial cells and to determine whether infection by EHEC modulates this response. Here we show that Stx is a potent inducer of the inflammatory response in intestinal epithelial cells and confirm that EHEC attenuates the induction of IL-8 by host-derived proinflammatory cytokines. More importantly, however, we show that infection with EHEC attenuates the inflammatory response by intestinal epithelial cells to its own toxin. We speculate that the ability of EHEC to dampen epithelial cell inflammatory responses to Stx and cytokines facilitates intestinal colonization.
View details for DOI 10.1152/ajpgi.00050.2009
View details for Web of Science ID 000269366800017
View details for PubMedID 19556613
View details for PubMedCentralID PMC2739818
- Anti-TNF antibodies associated with different risk of latent tuberculosis activation - Reply AMERICAN JOURNAL OF MEDICINE 2007; 120 (12): E23
Ambient particulate matter accelerates coagulation via an IL-6-dependent pathway
JOURNAL OF CLINICAL INVESTIGATION
2007; 117 (10): 2952-2961
The mechanisms by which exposure to particulate matter increases the risk of cardiovascular events are not known. Recent human and animal data suggest that particulate matter may induce alterations in hemostatic factors. In this study we determined the mechanisms by which particulate matter might accelerate thrombosis. We found that mice treated with a dose of well characterized particulate matter of less than 10 microM in diameter exhibited a shortened bleeding time, decreased prothrombin and partial thromboplastin times (decreased plasma clotting times), increased levels of fibrinogen, and increased activity of factor II, VIII, and X. This prothrombotic tendency was associated with increased generation of intravascular thrombin, an acceleration of arterial thrombosis, and an increase in bronchoalveolar fluid concentration of the prothrombotic cytokine IL-6. Knockout mice lacking IL-6 were protected against particulate matter-induced intravascular thrombin formation and the acceleration of arterial thrombosis. Depletion of macrophages by the intratracheal administration of liposomal clodronate attenuated particulate matter-induced IL-6 production and the resultant prothrombotic tendency. Our findings suggest that exposure to particulate matter triggers IL-6 production by alveolar macrophages, resulting in reduced clotting times, intravascular thrombin formation, and accelerated arterial thrombosis. These results provide a potential mechanism linking ambient particulate matter exposure and thrombotic events.
View details for DOI 10.1172/JCI30639
View details for Web of Science ID 000249894400026
View details for PubMedID 17885684
View details for PubMedCentralID PMC1978421
Electroporation-mediated gene transfer of the Na+, K+-ATPase rescues endotoxin-induced lung injury
AMERICAN JOURNAL OF RESPIRATORY AND CRITICAL CARE MEDICINE
2007; 176 (6): 582-590
Acute lung injury and acute respiratory distress syndrome are common clinical syndromes resulting largely from the accumulation of and inability to clear pulmonary edema, due to injury to the alveolar epithelium. Gene therapy may represent an important alternative for the treatment and prevention of these diseases by restoring alveolar epithelial function. We have recently developed an electroporation strategy to transfer genes to the lungs of mice, with high efficiency and low inflammation.We asked whether electroporation-mediated transfer of genes encoding subunits of the Na+,K+ -ATPase could protect from LPS-induced lung injury or be used to treat already injured lungs by up-regulating mechanisms of pulmonary edema clearance.Plasmids were delivered to the lungs of mice using transthoracic electroporation. Lung injury was induced by intratracheal administration of LPS (4 mg/kg body weight). Biochemical, cellular, and physiologic measurements were taken to assess gene transfer and lung injury.Improvements in wet-to-dry ratios, pulmonary effusions, bronchoalveolar lavage protein levels and cellularity, alveolar fluid clearance, and respiratory mechanics were seen after delivery of plasmids expressing Na+,K+ -ATPase subunits, but not control plasmids, in LPS-injured lungs. Delivery of plasmids expressing Na+,K+ -ATPase subunits both protected from subsequent lung injury and partially reversed existing lung injury by these measures.These results demonstrate that electroporation can be used effectively in healthy and injured lungs to facilitate gene delivery and expression. To our knowledge, this is the first successful use of gene delivery to treat existing lung injury, and may have future clinical potential.
View details for DOI 10.1164/rccm.200608-1246OC
View details for Web of Science ID 000249646100008
View details for PubMedID 17556717
View details for PubMedCentralID PMC1994223
The intrinsic apoptotic pathway is required for lipopolysaccharide-induced lung endothelial cell death
JOURNAL OF IMMUNOLOGY
2007; 179 (3): 1834-1841
LPS has been implicated in the pathogenesis of endothelial cell death associated with Gram-negative bacterial sepsis. The binding of LPS to the TLR-4 on the surface of endothelial cells initiates the formation of a death-inducing signaling complex at the cell surface. The subsequent signaling pathways that result in apoptotic cell death remain unclear and may differ among endothelial cells in different organs. We sought to determine whether LPS and cycloheximide-induced cell death in human lung microvascular endothelial cells (HmVECs) was dependent upon activation of the intrinsic apoptotic pathway and the generation of reactive oxygen species. We found that cells overexpressing the anti-apoptotic protein Bcl-X(L) were resistant to LPS and cycloheximide-induced death and that the proapoptotic Bcl-2 protein Bid was cleaved following treatment with LPS. The importance of Bid was confirmed by protection of Bid-deficient (bid(-/-)) mice from LPS-induced lung injury. Neither HmVECs treated with the combined superoxide dismutase/catalase mimetic EUK-134 nor HmVECs depleted of mitochondrial DNA (rho(0) cells) were protected against LPS and cycloheximide-induced death. We conclude that LPS and cycloheximide-induced death in HmVECs requires the intrinsic cell death pathway, but not the generation of reactive oxygen species.
View details for DOI 10.4049/jimmunol.179.3.1834
View details for Web of Science ID 000248319700047
View details for PubMedID 17641050
Leptin resistance protects mice from hyperoxia-induced acute lung injury
AMERICAN JOURNAL OF RESPIRATORY AND CRITICAL CARE MEDICINE
2007; 175 (6): 587-594
Human data suggest that the incidence of acute lung injury is reduced in patients with type II diabetes mellitus. However, the mechanisms by which diabetes confers protection from lung injury are unknown.To determine whether leptin resistance, which is seen in humans with diabetes, protects mice from hyperoxic lung injury.Wild-type (leptin responsive) and db/db (leptin resistant) mice were used in these studies. Mice were exposed to hyperoxia (100% O(2)) for 84 hours to induce lung injury and up to 168 hours for survival studies. Alveolar fluid clearance was measured in vivo.Lung leptin levels were increased both in wild-type and leptin receptor-defective db/db mice after hyperoxia. Hyperoxia-induced lung injury was decreased in db/db compared with wild-type mice. Hyperoxia increased lung permeability in wild-type mice but not in db/db mice. Compared with wild-type control animals, db/db mice were resistant to hyperoxia-induced mortality (lethal dose for 50% of mice, 152 vs. 108 h). Intratracheal instillation of leptin at a dose that was observed in the bronchoalveolar lavage fluid during hyperoxia caused lung injury in wild-type but not in db/db mice. Intratracheal pretreatment with a leptin receptor inhibitor attenuated leptin-induced lung edema. The hyperoxia-induced release of proinflammatory cytokines was attenuated in db/db mice. Despite resistance to lung injury, db/db mice had diminished alveolar fluid clearance and reduced Na,K-ATPase function compared with wild-type mice.These results indicate that leptin can induce and that resistance to leptin attenuates hyperoxia-induced lung injury and hyperoxia-induced inflammatory cytokines in the lung.
View details for DOI 10.1164/rccm.200603-312OC
View details for Web of Science ID 000244978600011
View details for PubMedID 17185651
View details for PubMedCentralID PMC1899284
Adenosine regulation of alveolar fluid clearance
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
2007; 104 (10): 4083-4088
Adenosine is a purine nucleoside that regulates cell function through G protein-coupled receptors that activate or inhibit adenylyl cyclase. Based on the understanding that cAMP regulates alveolar epithelial active Na(+) transport, we hypothesized that adenosine and its receptors have the potential to regulate alveolar ion transport and airspace fluid content. Herein, we report that type 1 (A(1)R), 2a (A(2a)R), 2b (A(2b)R), and 3 (A(3)R) adenosine receptors are present in rat and mouse lungs and alveolar type 1 and 2 epithelial cells (AT1 and AT2). Rat AT2 cells generated and produced cAMP in response to adenosine, and micromolar concentrations of adenosine were measured in bronchoalveolar lavage fluid from mice. Ussing chamber studies of rat AT2 cells indicated that adenosine affects ion transport through engagement of A(1)R, A(2a)R, and/or A(3)R through a mechanism that increases CFTR and amiloride-sensitive channel function. Intratracheal instillation of low concentrations of adenosine (< or =10(-8)M) or either A(2a)R- or A(3)R-specific agonists increased alveolar fluid clearance (AFC), whereas physiologic concentrations of adenosine (> or =10(-6)M) reduced AFC in mice and rats via an A(1)R-dependent pathway. Instillation of a CFTR inhibitor (CFTR(inh-172)) attenuated adenosine-mediated down-regulation of AFC, suggesting that adenosine causes Cl(-) efflux by means of CFTR. These studies report a role for adenosine in regulation of alveolar ion transport and fluid clearance. These findings suggest that physiologic concentrations of adenosine allow the alveolar epithelium to counterbalance active Na(+) absorption with Cl(-) efflux through engagement of the A(1)R and raise the possibility that adenosine receptor ligands can be used to treat pulmonary edema.
View details for DOI 10.1073/pnas.0601117104
View details for Web of Science ID 000244972400074
View details for PubMedID 17360481
View details for PubMedCentralID PMC1820712
- Air pollution impairs lung's ability to clear edema fluid AMERICAN JOURNAL OF CARDIOLOGY 2006; 98 (3): 423-424
Pulmonary adverse events of anti-tumor necrosis factor-alpha antibody therapy
AMERICAN JOURNAL OF MEDICINE
2006; 119 (8): 639-646
It is well established that anti-tumor necrosis factor-alpha (TNFalpha) antibody is an efficacious disease-modifying drug for rheumatoid arthritis and Crohn's disease. Unfortunately, its long-term use can be associated with ominous pulmonary adverse events, most notably mycobacterial and fungal lung infections. To this end, reactivation of latent tuberculosis infection represents a serious concern of anti-TNFalpha antibody therapy. Given the anticipated increase in the approved indications for these drugs, community-based physicians should be made aware of these events for implementation of better patient selection for anti-TNFalpha antibody therapy and initiation of appropriate measures once these adverse events are observed. This review will address this issue by outlining: 1) the role of TNFalpha in host inflammatory response to injury, particularly during mycobacterial and fungal infections; 2) the salutary effects of anti-TNFalpha antibody therapy in human diseases; and 3) the ominous pulmonary adverse events associated with these drugs.
View details for DOI 10.1016/j.amjmed.2006.01.015
View details for Web of Science ID 000239549900003
View details for PubMedID 16887405
Airborne particulate matter inhibits alveolar fluid reabsorption in mice via oxidant generation
AMERICAN JOURNAL OF RESPIRATORY CELL AND MOLECULAR BIOLOGY
2006; 34 (6): 670-676
Ambient particulate matter is increasingly recognized as a significant contributor to human cardiopulmonary morbidity and mortality in the United States and worldwide. We sought to determine whether exposure to ambient particulate matter would alter alveolar fluid clearance in mice. Mice were exposed to a range of doses of a well-characterized particulate matter collected from the ambient air in Düsseldorf, Germany through a single intratracheal instillation, and alveolar fluid clearance and measurements of lung injury were made. Exposure to even very low doses of particulate matter (10 microg) resulted in a significant reduction in alveolar fluid clearance that was maximal 24 h after the exposure, with complete resolution after 7 d. This was paralleled by a decrease in lung Na,K-ATPase activity. To investigate the mechanism of this effect, we measured plasma membrane Na,K-ATPase abundance in A549 cells and Na,K-ATPase activity in primary rat alveolar type II cells after exposure to particulate matter in the presence or absence of the combined superoxide dismutase and catalase mimetic EUK-134 (5 microM). Membrane but not total protein abundance of the Na,K-ATPase was decreased after exposure to particulate matter, as was Na,K-ATPase activity. This decrease was prevented by the combined superoxide dismutase/catalase mimetic EUK-134. The intratracheal instillation of particulate matter results in alveolar epithelial injury and decreased alveolar fluid clearance, conceivably due to downregulation of the Na,K-ATPase.
View details for DOI 10.1165/rcmb.2005-0329OC
View details for Web of Science ID 000237962300007
View details for PubMedID 16439801
View details for PubMedCentralID PMC2644228
Proapoptotic bid is required for pulmonary fibrosis
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
2006; 103 (12): 4604-4609
The molecular mechanisms of pulmonary fibrosis are poorly understood. Previous reports indicate that activation of TGF-beta1 is essential for the development of pulmonary fibrosis. Here, we report that the proapoptotic Bcl-2 family member Bid is required for the development of pulmonary fibrosis after the intratracheal instillation of bleomycin. Mice lacking Bid exhibited significantly less pulmonary fibrosis in response to bleomycin compared with WT mice. The attenuation in pulmonary fibrosis was observed despite similar levels of inflammation, lung injury, and active TGF-beta1 in bronchoalveolar lavage fluid 5 days after the administration of bleomycin in mice lacking Bid and in WT controls. Bleomycin induced similar levels cell death in vitro in alveolar epithelial cells isolated from WT and bid(-/-) mice. By contrast, alveolar epithelial cells from bid(-/-) mice were resistant to TGF-beta1-induced cell death. These results indicate that Bcl-2 family members are critical regulators for the development of pulmonary fibrosis downstream of TGF-beta1 activation.
View details for DOI 10.1073/pnas.0507604103
View details for Web of Science ID 000236362600051
View details for PubMedID 16537427
View details for PubMedCentralID PMC1401229
The protooncogene c-Myc is an essential regulator of neural crest formation in Xenopus
2003; 4 (6): 827-839
The neural crest, a population of multipotent progenitor cells, is a defining feature of vertebrate embryos. Neural crest precursor cells arise at the neural plate border in response to inductive signals, but much remains to be learned about the molecular mechanisms underlying their induction. Here we show that the protooncogene c-Myc is an essential early regulator of neural crest cell formation in Xenopus. c-myc is localized at the neural plate border prior to the expression of early neural crest markers, such as slug. A morpholino-mediated "knockdown" of c-Myc protein results in the absence of neural crest precursor cells and a resultant loss of neural crest derivatives. These effects are not dependent upon changes in cell proliferation or cell death. Instead, our findings reveal an important and unexpected role for c-Myc in the specification of cell fates in the early ectoderm.
View details for DOI 10.1016/S1534-5807(03)00160-6
View details for Web of Science ID 000183383100008
View details for PubMedID 12791268
Trafficking of cell-surface beta-amyloid precursor protein: Evidence that a sorting intermediate participates in synaptic vesicle recycling
JOURNAL OF NEUROSCIENCE
1997; 17 (1): 140-151
We recently demonstrated that the Alzheimer's beta-amyloid precursor protein (APP) is internalized from the axonal cell surface. In this study, we use biochemical and cell biological methods to characterize endocytotic compartments that participate in trafficking of APP in central neurons. APP is present in presynaptic clathrin-coated vesicles purified from bovine brain, together with the recycling synaptic vesicle integral membrane proteins synaptophysin, synaptotagmin, and SV2. In contrast, APP is largely excluded from synaptic vesicles purified from rat brain. In primary cerebellar macroneurons, cell-surface APP is internalized with recycling synaptic vesicle integral membrane proteins but is subsequently sorted away from synaptic vesicles and transported retrogradely to the neuronal soma. Internalized APP partially co-localizes with rab5a-containing compartments in axons and with V-ATPase-containing compartments in both axons and neuronal soma. These results provide direct biochemical evidence that an obligate sorting compartment participates in the regeneration of synaptic vesicles during exo/endocytotic recycling at nerve terminals but do not preclude concurrent "kiss-and-run" recycling. Moreover, APP is now, to our knowledge, the first demonstrated example of an axonal cell-surface protein that is internalized with recycling synaptic vesicle membrane proteins but is subsequently sorted away from synaptic vesicles.
View details for DOI 10.1523/JNEUROSCI.17-01-00140.1997
View details for Web of Science ID A1997WJ67700013
View details for PubMedID 8987743
View details for PubMedCentralID PMC6793693