I have worked at LPCH/Stanford for over 20 years. The Pediatric Pulmonary Division has grown substantially since I began. I am the medical director of the pediatric lung and heart-lung transplantation program here at Packard Children's Stanford. The program began in 2004, and by learning from the surgeons Dr. Norm Shumway and Dr. Bruce Reitz who pioneered this life-saving procedure in the 70's and 80's, I have directed the pediatric lung transplant program independent from the adult program since 2009.
My research interests focus on lung inflammation and transplantation and have evolved to study bronchiolitis obliterans/CLAD in lung transplant recipients. My program participates in ongoing NIH- sponsored clinical interventional trials in pediatric lung transplantation.
- Pulmonary Medicine/Cystic Fibrosis, Pediatric
- Lung Transplantation
- Heart-Lung Transplantation
- Lung Inflammation
- Interstitial Lung Disease in Children
- Pediatric Pulmonary
Director, Pediatric Lung and Heart-Lung Transplant Program (2004 - Present)
Director, Pediatric Pulmonary Function Lab (1999 - Present)
Boards, Advisory Committees, Professional Organizations
Vice-Chair, Pediatric Heart Failure and Thoracic Committee, ISHLT (2017 - Present)
Fellowship: Johns Hopkins Pediatric Pulmonology Fellowship (1995) MD
Residency: Childrens Hospital Los Angeles Pediatric Residency (1992) CA
Medical Education: UCLA David Geffen School Of Medicine Registrar (1989) CA
Board Certification: American Board of Pediatrics, Pediatric Pulmonary (1996)
Fellow, The Johns Hopkins University, Pediatric Pulmonary Medicine (1995)
BA, Univ. of California, Berkeley, Anatomy and Physiology (1983)
MD, Drew-UCLA School of Medicine, Medicine (1989)
Community and International Work
Chair, Pediatric Committee of the California Thoracic Society
Development of guidelines for care for pediatric respiratory disease
American Lung Association
Children who have chronic lung disease in the state of California
Opportunities for Student Involvement
Current Research and Scholarly Interests
I have participated in multiple clinical studies and have contributed to the development of therapeutic interventions designed specifically for the treatment of lung disease in children and adults with CF. Initially, my research interests concentrated on gene therapy for CF. Over time, the emphasis of my research led to investigator-initiated clinical research studies which have produced the description of novel mechanisms that drive the inflammatory milieu of the CF airway. With support from the CF Research Center resources at Stanford University, the CF Foundation, and the Food and Drug Administration, I have successfully completed Phase I and Phase IIa clinical research studies to assess the efficacy of N-acetylcysteine (NAC) in a novel approach to reduce inflammation in the lungs of CF patients. Building upon the foundation of these initial trials, and with CFF support, I completed a 3-years study, and was the Principal Investigator for a Phase II, multi-center trial for NAC in CF that began in November of 2008. The results of this study are published in the November issue of the Journal of Cystic Fibrosis.
As the pulmonary division has grown over the years, my clinical and academic interests have broadened to include pediatric lung transplantation. In 2002, I subsumed the role of program director for the pediatric pulmonary lung and heart-lung transplant program at LPCH. As a result, we are the 5th largest pediatric lung and heart-lung transplant program in the United States (the 2nd largest pediatric heart-lung transplant program) and the only pediatric lung transplant center in the Southwest, West, and Northwest region of the country (not including Texas). At least 100 infants and children have been evaluated at the center for pediatric lung and heart-lung transplantation at LPCH and 37 children have received transplants in this period of time.
My career plans are to foster further growth of the center with the goal to create a translational pediatric research center for lung and heart-lung transplantation at LPCH.
This nascent field of medicine is one in which little is known of the cellular and molecular mechanisms within transplantation dynamics and where the possibilities for discovery and therapeutic advances are considerable. In this field, I have co-authored several peer-reviewed manuscripts and abstracts, and I am a PI in international studies regarding outcomes for children who have undergone lung and heart-lung transplantation. The pediatric lung and heart-lung transplant program at LPCH is one of seven sites that participated in an international prospective study funded by the Clinical Trials in Organ Transplantation in Children (CTOT-C) from the NIH that will examine the effect that viral infections may have on the mechanisms of lung allograft rejection (development of bronchiolitis obliterans, OB) in children. OB is the single most important life-limiting process affecting lung and heart-lung transplant recipients. It is a fibrosing process that obliterates the allograft airway lumen. Once the process is initiated, it is difficult to abrogate. The etiology is poorly understood, and multifactorial. Most transplant researchers agree that ischemia-reperfusion injury (IRI) creates an abnormal cellular redox milieu that contributes to neutrophilic inflammation. Histopathologically, neutrophilic inflammation heralds the pathophysiologic consequences that result in graft failure due to OB. To date, the association of these early IRI and redox events to the occurrence of OB has not been fully investigated.
In 2014, the CTOT centers will proceed to an RDBPC study that will examine the effects of B-cell directed induction in combination with T-cell induction regimens on the effect of survival without BOS.
Rare Genetic Disorders of the Breathing Airways
Mucociliary clearance, in which mucus secretions are cleared from the breathing airways, is the primary defense mechanism for the lungs. Inhaled particles, including microbes that can cause infections, are normally entrapped in mucus on the airway surfaces and then cleared out by the coordinated action of tiny hair-like structures called cilia. Individuals with primary ciliary dyskinesia, variant cystic fibrosis, and pseudohypoaldosteronism have defective mucociliary clearance. The purpose of this study is to collect clinical and genetic information about these three airway diseases to improve current diagnostic procedures.
B Cell Induction in Pediatric Lung Transplantation
In this study, doctors are trying to see if a study drug called rituximab (Rituxan®) will lower the number of B cells in the body. Doctors are also trying to see if decreasing B cells with rituximab (Rituxan®) can prevent injury to the transplanted lung. This treatment has been studied in other types of solid organ transplants.
Stanford is currently not accepting patients for this trial. For more information, please contact Elisabeth Merkel, 650-736-0644.
NAC Phase IIB: A Multi-Center, Phase IIB, Randomized, Placebo-controlled, Double-Blind Study Of The Effects Of N-Acetylcysteine On Redox Changes and Lung Inflammation In Cystic Fibrosis Patients
This Phase IIB proof-of-concept study would examine the effects of an investigational product called N-acetylcysteine (NAC) on the basic processes that cause inflammation in CF lung disease. We hope to learn more about the causes of lung disease in cystic fibrosis by studying the characteristics of the inflammation in the lungs of patients who have CF.
Stanford is currently not accepting patients for this trial. For more information, please contact Spectrum Child Health, 650-724-1175.
Outcome Measures in Infant/Early Childhood Lung Disease w/ Chest CT Scanning & Lung Function Testing
To implement a new method of performing chest CT imaging in young children at Packard Children's Hospital entitled controlled ventilation infant/young child chest CT scanning. This technique will be used to evaluate early lung disease comparing quantitative chest CT air trapping and airway measurements with lung function measurements in infants, toddlers, and young children with chronic lung disease.
Stanford is currently not accepting patients for this trial. For more information, please contact Yan Ki Angela Leung, 650-723-5193.
The EPIC Observational Study
The purpose of this study is to better define risk factors preceding first isolation of Pseudomonas aeruginosa (Pa) from respiratory cultures in cystic fibrosis (CF) lung disease and to better define clinical outcomes associated with acquisition of Pa. This study will also collect and bank DNA samples for current and future studies designed to enhance the understanding of the pathogenesis of CF.
Stanford is currently not accepting patients for this trial. For more information, please contact Colleen Dunn, (650) 736 - 0388.
Graduate and Fellowship Programs
Pediatric Pulmonology (Fellowship Program)
The USnational registry for childhood interstitial and diffuse lung disease: Report of study design and initial enrollment cohort.
INTRODUCTION: Childhood interstitial and diffuse lung disease (chILD) encompasses a broad spectrum of rare disorders. The Children's Interstitial and Diffuse Lung Disease Research Network (chILDRN) established a prospective registry to advance knowledge regarding etiology, phenotype, natural history, and management of these disorders.METHODS: This longitudinal, observational, multicenter registry utilizes single-IRB reliance agreements, with participation from 25 chILDRN centers across the U.S. Clinical data are collected and managed using the Research Electronic Data Capture (REDCap) electronic data platform.RESULTS: We report the study design and selected elements of the initial Registry enrollment cohort, which includes 683 subjects with a broad range of chILD diagnoses. The most common diagnosis reported was neuroendocrine cell hyperplasia of infancy, with 155 (23%) subjects. Components of underlying disease biology were identified by enrolling sites, with cohorts of interstitial fibrosis, immune dysregulation, and airway disease being most commonly reported. Prominent morbidities affecting enrolled children included home supplemental oxygen use (63%) and failure to thrive (46%).CONCLUSION: This Registry is the largest longitudinal chILD cohort in the United States to date, providing a powerful framework for collaborating centers committed to improving the understanding and treatment of these rare disorders.
View details for DOI 10.1002/ppul.26568
View details for PubMedID 37401889
Macrophage Lysosomal Alkalinization Drives Invasive Aspergillosis in a Mouse Cystic Fibrosis Model of Airway Transplantation.
Journal of fungi (Basel, Switzerland)
2022; 8 (7)
Cystic fibrosis (CF) lung transplant recipients (LTRs) exhibit a disproportionately high rate of life-threatening invasive aspergillosis (IA). Loss of the cystic fibrosis transmembrane conductance regulator (CFTR-/-) in macrophages (mphis) has been associated with lyosomal alkalinization. We hypothesize that this alkalinization would persist in the iron-laden post-transplant microenvironment increasing the risk of IA. To investigate our hypothesis, we developed a murine CF orthotopic tracheal transplant (OTT) model. Iron levels were detected by immunofluorescence staining and colorimetric assays. Aspergillus fumigatus (Af) invasion was evaluated by Grocott methenamine silver staining. Phagocytosis and killing of Af conidia were examined by flow cytometry and confocal microscopy. pH and lysosomal acidification were measured by LysoSensorTM and LysotrackerTM, respectively. Af was more invasive in the CF airway transplant recipient compared to the WT recipient (p < 0.05). CFTR-/- mphis were alkaline at baseline, a characteristic that was increased with iron-overload. These CFTR-/- mphis were unable to phagocytose and kill Af conidia (p < 0.001). Poly(lactic-co-glycolic acid) (PLGA) nanoparticles acidified lysosomes, restoring the CFTR-/- mphis' ability to clear conidia. Our results suggest that CFTR-/- mphis' alkalinization interacts with the iron-loaded transplant microenvironment, decreasing the CF-mphis' ability to kill Af conidia, which may explain the increased risk of IA. Therapeutic pH modulation after transplantation could decrease the risk of IA.
View details for DOI 10.3390/jof8070751
View details for PubMedID 35887506
Auto-inflammation and auto-immunity pathways are associated with emergence of BOS in pediatric lung transplantation.
Long-term survival after lung transplantation (LTx) is limited by chronic lung allograft dysfunction (CLAD).We report an analysis of cytokine profiles in bronchoalveolar lavage samples collected during a prospective multicenter non-interventional trial primarily designed to determine the impact of community-acquired respiratory viral infections (CARV) in outcomes after pediatric LTx. In this analysis, we identify potential biomarkers of auto-inflammation and auto-immunity associated with survival and risk of bronchiolitis obliterans (BOS) after LTx with cytokine analysis of bronchoalveolar lavage fluid (BALF) from 61 pediatric recipients.Higher IL-23 (p = .048) and IL-31 (p = .035) levels were associated with the risk of BOS, and lower levels of epithelial growth factor (EGF) (p = .041) and eotaxin (EOX) (p = .017) were associated with BOS. Analysis using conditional inference trees to evaluate cytokines at each visit associated with survival identified soluble CD30 (p < .001), pro-inflammatory cytokine IL-23 (p = .02), and sTNFRI (p = .01) below cutoff levels as associated with BOS-free survival.Our results indicate that post-LTx survival in children may be linked to activation of alternate pathways of the immune system that affect airway remodeling in addition to activation of "classical" pathways that have been described in adult LTx recipients. These may indicate pathways to target for intervention.
View details for DOI 10.1111/petr.14247
View details for PubMedID 35146849
CTOTC-08: A multicenter randomized controlled trial of rituximab induction to reduce antibody development and improve outcomes in pediatric lung transplant recipients.
American journal of transplantation : official journal of the American Society of Transplantation and the American Society of Transplant Surgeons
We conducted a randomized, placebo-controlled, double-blind study of pediatric lung transplant recipients, hypothesizing that rituximab plus rabbit anti-thymocyte globulin induction would reduce de novo donor-specific human leukocyte antigen antibodies (DSA) development and improve outcomes. We serially obtained clinical data, blood, and respiratory samples for at least one year post transplant. We analyzed peripheral blood lymphocytes by flow cytometry, serum for antibody development, and respiratory samples for viral infections using multiplex PCR. Of 45 subjects enrolled, 34 were transplanted and 27 randomized to rituximab (n=15) or placebo (n=12). No rituximab-treated subjects versus 5 placebo-treated subjects developed de novo DSA with mean fluorescence intensity > 2000. There was no difference between treatment groups in time to the primary composite outcome endpoint (death, bronchiolitis obliterans syndrome (BOS) grade 0-p, obliterative bronchiolitis or listing for retransplant). A post-hoc analysis substituting more stringent chronic lung allograft dysfunction criteria for BOS 0-p showed no difference in outcome (p=0.118). Incidence of adverse events including infection and rejection episodes was no different between treatment groups. Although the study was underpowered, we conclude that rituximab induction may have prevented early DSA development in pediatric lung transplant recipients without adverse effects and may improve outcomes.
View details for DOI 10.1111/ajt.16862
View details for PubMedID 34599540
Remote intervention engagement and outcomes in the Clinical Trials in Organ Transplantation in Children consortium multisite trial
AMERICAN JOURNAL OF TRANSPLANTATION
2021; 21 (9): 3112-3122
Remote interventions are increasingly used in transplant medicine but have rarely been rigorously evaluated. We investigated a remote intervention targeting immunosuppressant management in pediatric lung transplant recipients. Patients were recruited from a larger multisite trial if they had a Medication Level Variability Index (MLVI) ≥2.0, indicating worrisome tacrolimus level fluctuation. The manualized intervention included three weekly phone calls and regular follow-up calls. A comparison group included patients who met enrollment criteria after the subprotocol ended. Outcomes were defined before the intent-to-treat analysis. Feasibility was defined as ≥50% of participants completing the weekly calls. MLVI was compared pre- and 180 days postenrollment and between intervention and comparison groups. Of 18 eligible patients, 15 enrolled. Seven additional patients served as the comparison. Seventy-five percent of participants completed ≥3 weekly calls; average time on protocol was 257.7 days. Average intervention group MLVI was significantly lower (indicating improved blood level stability) at 180 days postenrollment (2.9 ± 1.29) compared with pre-enrollment (4.6 ± 2.10), p = .02. At 180 days, MLVI decreased by 1.6 points in the intervention group but increased by 0.6 in the comparison group (p = .054). Participants successfully engaged in a long-term remote intervention, and their medication blood levels stabilized. NCT02266888.
View details for DOI 10.1111/ajt.16567
View details for Web of Science ID 000639211700001
View details for PubMedID 33752251
Epidemiology and persistence of rhinovirus in pediatric lung transplantation
TRANSPLANT INFECTIOUS DISEASE
2020; 22 (6): e13422
Infection with rhinovirus (HRV) occurs following pediatric lung transplantation. Prospective studies documenting frequencies, persistence, and progression of HRV in this at-risk population are lacking.In the Clinical Trials in Organ Transplant in Children prospective observational study, we followed 61 lung transplant recipients for 2 years. We quantified molecular subtypes of HRV in serially collected nasopharyngeal (NP) and bronchoalveolar lavage (BAL) samples and correlated them with clinical characteristics.We identified 135 community-acquired respiratory infections (CARV) from 397 BAL and 480 NP samples. We detected 93 HRV events in 42 (68.8%) patients, 22 of which (23.4%) were symptomatic. HRV events were contiguous with different genotypes identified in 23 cases, but symptoms were not preferentially associated with any particular species. Nine (9.7%) HRV events persisted over multiple successive samples for a median of 36 days (range 18-408 days). Three persistent HRV were symptomatic. When we serially measured forced expiratory volume in one second (FEV1) in 23 subjects with events, we did not observe significant decreases in lung function over 12 months post-HRV.In conjunction with our previous reports, our prospectively collected data indicate that molecularly heterogeneous HRV infections occur commonly following pediatric lung transplantation, but these infections do not negatively impact clinical outcomes.
View details for DOI 10.1111/tid.13422
View details for Web of Science ID 000554378800001
View details for PubMedID 32686323
View details for PubMedCentralID PMC7900771
Update on pediatric lung transplantation: mir-ando into the mechanisms of chronic lung allograft dysfunction in children.
Current opinion in organ transplantation
PURPOSE OF REVIEW: Lung transplantation (LTx) is a worthwhile treatment for children with end-stage lung diseases who have no practicable medical or surgical solutions. But the long-term survival remains the lowest in all solid-organ transplant, with a median survival of 5.7 years, limited by the onset of chronic lung allograft dysfunction (CLAD). This reviews a recent publication in pediatric patients that focuses on translational regulation by microRNA.RECENT FINDINGS: The mechanisms that cause transplanted lung allografts have been difficult to identify. This review discusses pertinent findings in the first and largest observational prospective study of pediatric lung transplant recipients. The review discusses the relevance of microRNA that distinguish stable patients from those who can be predicted to display graft dysfunction on a molecular panel.SUMMARY: The article under review detected highly specific and sensitive markers of both acute rejection and CLAD in pediatric LTx recipients. With the use of next-generation sequencing techniques, biomarkers may soon provide the basis for earlier detection of graft function and stimulate development of therapeutic interventions to impact outcomes and survival. The review touches on the relevance of these findings and how future research can build on them.
View details for DOI 10.1097/MOT.0000000000000763
View details for PubMedID 32304424
Perceived barriers to medication adherence remain stable following solid organ transplantation
2019; 23 (3): e13361
Perceived barriers to adherence have previously been investigated in SOT to identify plausible intervention targets to improve adherence and transplant outcomes. Fifteen centers in CTOTC enrolled patients longitudinally. Patients >8 years completed Adolescent Scale(AMBS) at two visits at least 6 months apart in the first 17 months post-transplant while their guardians completed PMBS. Differences over time for pre-identified AMBS/PMBS factors were analyzed. Perceived barrier reporting impact on subsequent TAC levels was assessed. A total of 123 patients or their guardians completed PMBS or AMBS. Twenty-six were 6-11 years and 97 were ≥12. The final cohort consisted of kidney (66%), lung (19%), liver (8%), and heart (7%) recipients. Unadjusted analysis showed no statistically significant change in reported barriers from visit 1 (median 2.6 months, range 1.2-3.7 post-transplant) to visit 2 (median 12, range 8.9-16.5). Of 102 patients with TAC levels, 74 had a single level reported at both visits. The factor of "Disease frustration" was identified through the PMBS/AMBS questions about fatigue around medication and disease. Each point increase in "disease frustration" at visit 1 on the AMBS/PMBS doubled the odds of a lower-than-threshold TAC level at visit 2. No clear change in overall level of perceived barriers to medication adherence in the first year post-transplant was seen in pediatric SOT. However, disease frustration early post-transplant was associated with a single subtherapeutic TAC levels at 12 months. A brief screening measure may allow for early self-identification of risk.
View details for DOI 10.1111/petr.13361
View details for Web of Science ID 000476931300006
View details for PubMedID 31332928
View details for PubMedCentralID PMC6652201
- Resistin is elevated in cystic fibrosis sputum and correlates negatively with lung function JOURNAL OF CYSTIC FIBROSIS 2019; 18 (1): 64–70
- A national registry for childhood interstitial and diffuse lung diseases in the United States. EUROPEAN RESPIRATORY SOC JOURNALS LTD. 2018
- An alternative cannulation approach for venovenous extracorporeal membrane oxygenation in children for long-term ambulatory support JOURNAL OF THORACIC AND CARDIOVASCULAR SURGERY 2018; 156 (1): E13–E14
An alternative cannulation approach for venovenous extracorporeal membrane oxygenation in children for long-term ambulatory support.
The Journal of thoracic and cardiovascular surgery
View details for PubMedID 29685584
Anellovirus loads are associated with outcomes in pediatric lung transplantation
2018; 22 (1)
Anelloviruses are DNA viruses ubiquitously present in human blood. Due to their elevated levels in immunosuppressed patients, anellovirus levels have been proposed as a marker of immune status. We hypothesized that low anellovirus levels, reflecting relative immunocompetence, would be associated with adverse outcomes in pediatric lung transplantation. We assayed blood samples from 57 patients in a multicenter study for alpha- and betatorquevirus, two anellovirus genera. The primary short-term outcome of interest was acute rejection, and longer-term outcomes were analyzed individually and as "composite" (death, chronic rejection, or retransplant within 2 years). Patients with low alphatorquevirus levels at 2 weeks post-transplantation were more likely to develop acute rejection within 3 months after transplant (P = .013). Low betatorquevirus levels at 6 weeks and 6 months after transplant were associated with death (P = .047) and the composite outcome (P = .017), respectively. There was an association between low anellovirus levels and adverse outcomes in pediatric lung transplantation. Alphatorquevirus levels were associated with short-term outcomes (ie, acute rejection), while betatorquevirus levels were associated with longer-term outcomes (ie, death, or composite outcome within 2 years). These observations suggest that anelloviruses may serve as useful biomarkers of immune status and predictors of adverse outcomes.
View details for PubMedID 29082660
View details for PubMedCentralID PMC5811341
Resistin is elevated in cystic fibrosis sputum and correlates negatively with lung function.
Journal of cystic fibrosis : official journal of the European Cystic Fibrosis Society
Resistin is an immunometabolic mediator that is elevated in several inflammatory disorders. A ligand for Toll-like receptor 4, resistin modulates the recruitment and activation of myeloid cells, notably neutrophils. Neutrophils are major drivers of cystic fibrosis (CF) lung disease, in part due to the release of human neutrophil elastase- and myeloperoxidase-rich primary granules, leading to tissue damage. Here we assessed the relationship of resistin to CF lung disease.Resistin levels were measured in plasma and sputum from three retrospective CF cohorts spanning a wide range of disease. We also assessed the ability of neutrophils to secrete resistin upon activation in vitro. Finally, we constructed a multivariate model assessing the relationship between resistin levels and lung function.Plasma resistin levels were only marginally higher in CF than in healthy control subjects. By contrast, sputum resistin levels were very high in CF, reaching 50-100 fold higher levels than in plasma. Among CF patients, higher plasma resistin levels were associated with allergic bronchopulmonary aspergillosis, and higher sputum resistin levels were associated with CF-related diabetes. Mechanistically, in vitro release of neutrophil primary granules was concomitant with resistin secretion. Overall, sputum resistin levels were negatively correlated with CF lung function, independently of other variables (age, sex, and genotype).Our data establish relationships between resistin levels in the plasma and sputum of CF patients that correlate with disease status, and identify resistin as a novel mechanistic link between neutrophilic inflammation and lung disease in CF.
View details for PubMedID 29937317
Lung clearance index is sensitive to small airway disease in pediatric lung transplant recipients
JOURNAL OF HEART AND LUNG TRANSPLANTATION
2017; 36 (9): 980–84
The principal obstacle to long-term survival after lung transplant is chronic lung allograft dysfunction (CLAD), which primarily affects the small airways. After transplant, patients are monitored with spirometry, which is a generally insensitive detector of small airways obstruction. The lung clearance index (LCI) is a measure obtained during multiple breath washout (MBW) maneuvers. We hypothesized that among lung allograft recipients, LCI would detect small airways disease not detected with spirometry.This study enrolled 15 patients, 5 of whom already had a diagnosis of CLAD. We added MBW as an additional index of peripheral airway function to the established post-transplant routine care protocol.Of trials, 87.9% yielded valid measurements, and single maneuvers were 2-8 minutes. LCI did not yield any false-negative findings-no patients were considered obstructed by forced expiratory volume in 1 second (FEV1) but normal by LCI. At enrollment, 6 patients without CLAD had an elevated LCI, and 4 progressed to CLAD. Only 2 of these 4 patients would have been identified by a decrease in FEV1.LCI identified lung allograft dysfunction in more patients than the use of standardized spirometric measures, including patients with abnormal FEV1. These data suggest that LCI from MBW may be a more sensitive means to detect allograft peripheral airway disease than standard methods for measurement of small airways function.
View details for PubMedID 28651906
Current State of Pediatric Lung Transplantation
2015; 193 (5): 629-637
Cardiothoracic transplantation has significantly impacted the lives of pediatric patients with advanced cardiopulmonary failure. The current state of lung transplantation in children as well as its ongoing and future challenges are discussed.
View details for DOI 10.1007/s00408-015-9765-z
View details for Web of Science ID 000361820800002
View details for PubMedID 26238859
Long-term treatment with oral N-acetylcysteine: Affects lung. function but not sputum inflammation in cystic fibrosis subjects. A phase II randomized placebo-controlled trial
JOURNAL OF CYSTIC FIBROSIS
2015; 14 (2): 219-227
To evaluate the effects of oral N-acetylcysteine (NAC), which replenishes systemic glutathione, on decreasing inflammation and improving lung function in CF airways.A multicenter, randomized, double-blind proof of concept study in which 70 CF subjects received NAC or placebo orally thrice daily for 24weeks.primary, change in sputum human neutrophil elastase (HNE) activity; secondary, FEV1 and other clinical lung function measures; and safety, the safety and tolerability of NAC and the potential of NAC to promote pulmonary hypertension in subjects with CF.Lung function (FEV1 and FEF25-75%) remained stable or increased slightly in the NAC group but decreased in the placebo group (p=0.02 and 0.02). Log10 HNE activity remained equal between cohorts (difference 0.21, 95% CI -0.07 to 0.48, p=0.14).NAC recipients maintained their lung function while placebo recipients declined (24week FEV1 treatment effect=150mL, p<0.02). However no effect on HNE activity and other selected biomarkers of neutrophilic inflammation were detected. Further studies on mechanism and clinical outcomes are warranted.
View details for DOI 10.1016/j.jcf.2014.08.008
View details for Web of Science ID 000352662600008
View details for PubMedID 25228446
Cutaneous squamous cell carcinoma in two pediatric lung transplant patients on prolonged voriconazole treatment
2014; 18 (6): E200-E207
Oral voriconazole is commonly used for treatment and prophylaxis of invasive fungal disease post-LTx. Development of cutaneous SCC has been described in adult LTx recipients, although it is extremely rare in children. We describe two Caucasian children who developed cutaneous SCC beyond three yr post-LTx. Both developed severe photosensitivity, actinic keratosis and required curative surgical excision of the cutaneous SCC lesions. Neither patient developed metastatic lesions nor had allograft dysfunction as a result of the SCC or the change in medical treatments. The effect of voriconazole on the development of malignant skin lesions is discussed and a recommendation on dermatologic surveillance, preventive measures against phototoxicity and early treatment of SCC are provided.
View details for DOI 10.1111/petr.12320
View details for Web of Science ID 000340530800005
View details for PubMedID 25039541
Pediatric lung transplantation: promise being realized.
Current opinion in pediatrics
2014; 26 (3): 334-342
Lung transplantation for infants and children is an accepted but rarely exercised option for the treatment of end-stage lung disease, with outcomes equivalent to those for adults. However, widespread misconceptions regarding pediatric outcomes often confound timely and appropriate referral to specialty centers. We present the updated information for primary pediatricians to utilize when counseling families with children confronted by progressive end-stage pulmonary or cardiovascular disease.We provide general guidelines to consider for referral, and discuss allocation of organs in children, information regarding standard treatment protocols, and survival outcomes.Lung transplantation is a worthwhile treatment option to consider in children with end-stage lung disease. The treatment is complex, but lung transplant provides substantial survival benefit and markedly improved quality of life for children and their families. This timely review provides comprehensive information for pediatricians who are considering options for treatment of children with end-stage lung disease.
View details for DOI 10.1097/MOP.0000000000000085
View details for PubMedID 24732565
Association of lung function, chest radiographs and clinical features in infants with cystic fibrosis
EUROPEAN RESPIRATORY JOURNAL
2013; 42 (6): 1545-1552
The optimal strategy for monitoring cystic fibrosis lung disease in infancy remains unclear. Our objective was to describe longitudinal associations between infant pulmonary function tests, chest radiograph scores and other characteristics. Cystic fibrosis patients aged ≤24 months were enrolled in a 10-centre study evaluating infant pulmonary function tests four times over a year. Chest radiographs ∼1 year apart were scored using the Wisconsin and Brasfield systems. Associations of infant pulmonary function tests with clinical characteristics were evaluated with mixed effects models. The 100 participants contributed 246 acceptable flow/volume (forced expiratory volume in 0.5 s (FEV0.5) and forced expiratory flow at 75% of the forced vital capacity (FEF75%)), 303 functional residual capacity measurements and 171 chest radiographs. Both Brasfield and Wisconsin chest radiograph scores worsened significantly over the 1-year interval. Worse Wisconsin chest radiograph scores and Staphylococcus aureus were both associated with hyperinflation (significantly increased functional residual capacity), but not with diminished FEV0.5 or FEF75%. Parent-reported cough was associated with significantly diminished forced expiratory flow at 75% but not with hyperinflation. In this infant cohort in whom we previously reported worsening in average lung function, chest radiograph scores also worsened over a year. The significant associations detected between both Wisconsin chest radiograph score and S. aureus and hyperinflation, as well as between cough and diminished flows, reinforce the ability of infant pulmonary function tests and chest radiographs to detect early cystic fibrosis lung disease.
View details for DOI 10.1183/09031936.00138412
View details for Web of Science ID 000327919900018
View details for PubMedID 23722613
View details for PubMedCentralID PMC3795977
Metabolic Adaptation of Neutrophils in Cystic Fibrosis Airways Involves Distinct Shifts in Nutrient Transporter Expression
JOURNAL OF IMMUNOLOGY
2013; 190 (12): 6043-6050
Inflammatory conditions can profoundly alter human neutrophils, a leukocyte subset generally viewed as terminally differentiated and catabolic. In cystic fibrosis (CF) patients, neutrophils recruited to CF airways show active exocytosis and sustained phosphorylation of prosurvival, metabolic pathways. Because the CF airway lumen is also characterized by high levels of free glucose and amino acids, we compared surface expression of Glut1 (glucose) and ASCT2 (neutral amino acids) transporters, as well as that of PiT1 and PiT2 (inorganic phosphate transporters), in blood and airway neutrophils, using specific retroviral envelope-derived ligands. Neither nutrient transporter expression nor glucose uptake was altered on blood neutrophils from CF patients compared with healthy controls. Notably, however, airway neutrophils of CF patients had higher levels of PiT1 and Glut1 and increased glucose uptake compared with their blood counterparts. Based on primary granule exocytosis and scatter profiles, CF airway neutrophils could be divided into two subsets, with one of the subsets characterized by more salient increases in Glut1, ASCT2, PiT1, and PiT2 expression. Moreover, in vitro exocytosis assays of blood neutrophils suggest that surface nutrient transporter expression is not directly associated with primary (or secondary) granule exocytosis. Although expression of nutrient transporters on CF blood or airway neutrophils was not altered by genotype, age, gender, or Pseudomonas aeruginosa infection, oral steroid treatment decreased Glut1 and PiT2 levels in blood neutrophils. Thus, neutrophils recruited from blood into the CF airway lumen display augmented cell surface nutrient transporter expression and glucose uptake, consistent with metabolic adaptation.
View details for DOI 10.4049/jimmunol.1201755
View details for Web of Science ID 000320373700017
View details for PubMedID 23690474
Bilateral Lung Transplantation for Pediatric Idiopathic Pulmonary Arterial Hypertension: A Multi-Center Experience
2011; 46 (11): 1121-1127
Many children with idiopathic pulmonary arterial hypertension (IPAH) experience disease progression despite advanced medical therapy. In these children, heart-lung or bilateral lung transplantation (BLTx) remain the only therapeutic options when other treatments fail. Data on functional outcome after BLTx in children with IPAH are limited. We report a multi-center experience of BLTx for pediatric IPAH. We performed a retrospective study including 25 centers within the International Pediatric Lung Transplant Collaborative. Children with IPAH who underwent BLTx were included (1996-2006). Twenty-three children underwent BLTx for IPAH, most of whom were in WHO class III or IV level of function pre-transplantation. At 6 months post-transplantation, 82% of children reported improvement in level of function to WHO class I. The median FEV(1) was 89% (12-126) of predicted at 12 months post-transplantation. Ten patients (44%) developed BOS at a median of 42 months (3-85), of whom five died at a median of 27 months (4-86) post-transplantation. Overall mortality was 4% at 3 months post-transplantation. The median survival for children in this cohort was 45 months (2-123). Our data suggest that BLTx is a valuable therapeutic option for children with end-stage IPAH with outcomes comparable to that after heart-lung transplantation in children with pulmonary arterial hypertension or those patients undergoing lung transplantation for other indications. In the majority of children, a good cardiopulmonary function is possible following BLTx, making BLTx a good therapeutic option and maximizing donor organ utilization by allowing more hearts to be available for children needing cardiac transplantation.
View details for DOI 10.1002/ppul.21484
View details for Web of Science ID 000296491300011
View details for PubMedID 21634032
METABOLITE PROFILING OF CF AIRWAY FLUID SUGGESTS A ROLE FOR CATECHOLAMINES IN EARLY AND CHRONIC DISEASE
WILEY-BLACKWELL. 2011: 240–240
View details for Web of Science ID 000296071800163
Multicenter Evaluation of Infant Lung Function Tests as Cystic Fibrosis Clinical Trial Endpoints
AMERICAN JOURNAL OF RESPIRATORY AND CRITICAL CARE MEDICINE
2010; 182 (11): 1387-1397
The conducting of clinical trials in infants with cystic fibrosis (CF) has been hindered by lack of sensitive outcome measures.To evaluate safety, feasibility, and ability to detect abnormalities in lung function of serial pulmonary function tests (PFTs) in infants with CF.Multicenter observational study using a commercial device, rigorous training, ongoing quality control, and over-reading of data by an independent panel. Raised volume rapid thoracoabdominal compression technique and plethysmography were performed at enrollment and at 6 and 12 months, with an additional 1-month reproducibility visit.A total of 342 procedures were performed in 100 infants with CF at 10 centers. FRC measurements were acceptable at a higher proportion of study visits (89%) than raised volume (72%) or fractional lung volume (68%) measurements. Average Z scores for many parameters differed significantly from historical control values. Mean (95% confidence interval) Z scores were: -0.52 (-0.78 to -0.25) for forced expiratory flow at 75% (FEF₇₅) for FVC; 1.92 (1.39-2.45) for FRC; 1.22 (0.68-1.76) for residual volume; 0.87 (0.60-1.13) for FRC/total lung capacity; and 0.66 (0.27-1.06) for residual volume/total lung capacity. For future multicenter clinical trials using infant PFTs as primary endpoints, minimum detectable treatment effects are presented for several sample sizes.In this 10-center study, key PFT measures were significantly different in infants with CF than in historical control subjects. However, infant PFTs do not yet appear ready as primary efficacy endpoints for multicenter clinical trials, particularly at inexperienced sites, based on acceptability rates, variability, and potentially large sample sizes required to detect reasonable treatment effects.
View details for DOI 10.1164/rccm.200908-1236OC
View details for Web of Science ID 000285012900010
View details for PubMedID 20622043
View details for PubMedCentralID PMC3159081
Minimal acute rejection in pediatric lung transplantation - Does it matter?
2010; 14 (4): 534-539
In adult lung transplantation, a single minimal AR episode is a significant predictor of BOS independent of other factors. However, the significance of single minimal AR episodes in children is unknown. A retrospective, multi-center analysis was performed to determine whether isolated single AR episodes are associated with an increased BOS risk in children. Risk factors for BOS, death, or re-transplantation, and a combined outcome of BOS, death, or re-transplantation were assessed. Original data included 577 patients (<21 yr of age). A total of 383 subjects were eligible for the study. Fifteen percent of patients developed BOS, and 13% of patients either died or underwent re-transplant within one-yr post-transplant. In the multivariable survival model for time to BOS, there was no significant risk to developing BOS after a single minimal AR (A1) episode (HR 1.7, 95% CI 0.64-4.8; p=0.28). Even after a second minimal AR episode, no significant risk for BOS was appreciated. However, a single episode of mild AR (A2) was associated with twice the risk of BOS within one-yr post-transplant. In this select cohort, a single minimal AR episode was not associated with an increased risk for BOS within one yr following lung transplantation, in contrast to previous reports in adults.
View details for DOI 10.1111/j.1399-3046.2009.01268.x
View details for Web of Science ID 000277528900019
View details for PubMedID 20059725
View details for PubMedCentralID PMC2888626
- Lung transplantation for pediatric pulmonary hypertension PROGRESS IN PEDIATRIC CARDIOLOGY 2009; 27 (1-2): 49–55
Cytomegalovirus Immunoglobulin Decreases the Risk of Cytomegalovirus Infection but not Disease After Pediatric Lung Transplantation
JOURNAL OF HEART AND LUNG TRANSPLANTATION
2009; 28 (10): 1050-1056
Cytomegalovirus (CMV) has been associated with morbidity, including chronic allograft rejection, in transplant recipients. Data from adult centers suggests that CMV hyperimmune globulin (CMVIG) and ganciclovir together are superior in preventing CMV viremia than ganciclovir alone.A retrospective review of pediatric lung transplant recipients at 14 sites in North America and Europe was conducted to evaluate the effect of adding cytomegalovirus immunoglobulin (CMVIG) prophylaxis to at least 3 weeks of intravenous ganciclovir therapy in pediatric lung transplant recipients. Data were recorded for the first year after transplantation. Associations between time to CMV and risk factors, including CMVIG use, were assessed by multivariable Cox proportional hazards models.Of 599 patients whose records were reviewed, 329 received at least 3 weeks of ganciclovir, with 62 (19%) receiving CMVIG. CMVIG was administered more frequently with CMV donor-positive/recipient-negative serostatus (p < 0.05). In multivariable models, patients who did not receive CMVIG as part of their prophylaxis were 3 times more likely to develop CMV infection (hazard ratio, 3.4; 95% confidence interval, 1.2-9.5) independent of CMV serostatus. However, CMVIG administration was not associated with decreased risk of episodes of CMV disease. Receipt of CMVIG was not associated with decreased risks of post-transplant morbidities (acute rejection, respiratory viral infection or early bronchiolitis obliterans) or morbidity within the first year after pediatric lung transplantation.The use of CMVIG in addition to antiviral prophylaxis in pediatric lung transplantation requires further evaluation.
View details for DOI 10.1016/j.healun.2009.04.032
View details for Web of Science ID 000270918000006
View details for PubMedID 19782286
View details for PubMedCentralID PMC2771443
Respiratory viral infections within one year after pediatric lung transplant
TRANSPLANT INFECTIOUS DISEASE
2009; 11 (4): 304-312
To characterize epidemiology and risk factors for respiratory viral infections (RVI) in pediatric lung transplant recipients within the first post-transplant year, a retrospective multicenter study of pediatric lung transplant recipients from 1988 to 2005 was conducted at 14 centers in the United States and Europe. Data were recorded for 1 year post transplant. Associations between RVI and continuous and categorical risk factors were assessed using Wilcoxon's rank-sum and chi(2) tests, respectively. Associations between time to RVI and risk factors or survival were assessed by multivariable Cox proportional hazards models. Of 576 subjects, 79 subjects (14%) had 101 RVI in the first year post transplant. Subjects with RVI were younger than those without RVI (median ages 9.7, 13; P<0.01). Viruses detected included adenovirus (n=25), influenza (n=9), respiratory syncytial virus (n=21), parainfluenza virus (n=19), enterovirus (n=4), and rhinovirus (n=22). In a multivariable model for time to first RVI, etiology other than cystic fibrosis (CF), younger age, and no induction therapy were independently associated with risk of RVI. Cytomegalovirus serostatus and acute rejection were not associated with RVI. RVI was independently associated with decreased 12-month survival (hazard ratio 2.6, 95% confidence interval 1.6-4.4). RVI commonly occurs after pediatric lung transplantation with risk factors including younger age and non-CF diagnosis. RVI is associated with decreased 1-year survival.
View details for DOI 10.1111/j.1399-3062.2009.00397.x
View details for Web of Science ID 000268714600004
View details for PubMedID 19422670
The Risk, Prevention, and Outcome of Cytomegalovirus After Pediatric Lung Transplantation
World Transplant Congress
LIPPINCOTT WILLIAMS & WILKINS. 2009: 1541–48
A retrospective review of pediatric lung transplant recipients at 14 centers in North America and Europe was conducted to characterize the epidemiology and the risk factors for cytomegalovirus (CMV) and to explore the impact of preventative antiviral therapy.Data were recorded for 1 year posttransplant. Associations between CMV and continuous and categorical risk factors were assessed using Wilcoxon rank sum and chi-square tests, respectively. Associations between time to CMV and risk factors or survival were assessed by multivariable Cox proportional hazards models.Within 12 months posttransplant, 172 of 577 subjects (29.8%) developed 218 CMV episodes (90 asymptomatic infection, 25 syndrome, and 103 disease). Forty-one subjects developed more than one episode of CMV. Donor or recipient CMV seropositivity was associated with increased risk of CMV episodes. Except for decreased prophylaxis in CMV D-/R- subjects, duration of prophylaxis did not vary by D/R serostatus. For CMV D+ subjects, not being on prophylaxis at the time of CMV episode increased the risk of CMV (D+/R+ hazard ratio 3.5, 95% confidence interval 1.4-8.4; D+/R- 1.9, 1.02-3.7). CMV was associated with increased mortality within the first posttransplant year among those with donor or recipient CMV seropositivity (hazard ratio 2.0: 95% confidence interval 1.1-3.6; P=0.024).CMV remains a serious complication after pediatric lung transplant, and the impact of prophylaxis is complex.
View details for DOI 10.1097/TP.0b013e3181a492e8
View details for Web of Science ID 000266431500017
View details for PubMedID 19461492
View details for PubMedCentralID PMC2726779
Activation of critical, host-induced, metabolic and stress pathways marks neutrophil entry into cystic fibrosis lungs
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
2009; 106 (14): 5779-5783
Cystic fibrosis (CF) patients undergo progressive airway destruction caused in part by chronic neutrophilic inflammation. While opportunistic pathogens infecting CF airways can cause inflammation, we hypothesized that host-derived metabolic and stress signals would also play a role in this process. We show that neutrophils that have entered CF airways have increased phosphorylation of the eukaryotic initiation factor 4E and its partner the 4E-binding protein 1; 2 key effectors in the growth factor- and amino acid-regulated mammalian target of rapamycin (mTOR) pathway. Furthermore CF airway neutrophils display increased phosphorylation of the cAMP response element binding protein (CREB), a major transcriptional coactivator in stress signaling cascades. These active intracellular pathways are associated with increased surface expression of critical adaptor molecules, including the growth factor receptor CD114 and the receptor for advanced glycation end-products (RAGE), a CREB inducer and sensor for host-derived damage-associated molecular patterns (DAMPs). Most CF airway fluids lack any detectable soluble RAGE, an inhibitory decoy receptor for DAMPs. Concomitantly, CF airway fluids displayed high and consequently unopposed levels of S100A12; a potent mucosa- and neutrophil-derived DAMP. CF airway neutrophils also show increased surface levels of 2 critical CREB targets, the purine-recycling enzyme CD39 and the multifunctional, mTOR-inducing CXCR4 receptor. This coordinated set of events occurs in all patients, even in the context of minimal airway inflammation and well-preserved lung function. Taken together, our data demonstrate an early and sustained activation of host-responsive metabolic and stress pathways upon neutrophil entry into CF airways, suggesting potential targets for therapeutic modulation.
View details for DOI 10.1073/pnas.0813410106
View details for Web of Science ID 000264967500059
View details for PubMedID 19293384
View details for PubMedCentralID PMC2667067
- Activation of critical, host-induced, metabolic and stress pathways marks neutrophil entry into cystic fibrosis lungs Proc Natl Acad Sci 2009; 106 (14): 5779
Increased mortality after pulmonary fungal infection within the first year after pediatric lung transplantation
7th American Transplant Congress
ELSEVIER SCIENCE INC. 2008: 655–61
Risk factors, morbidity and mortality from pulmonary fungal infections (PFIs) within the first year after pediatric lung transplant have not previously been characterized.A retrospective, multicenter study from 1988 to 2005 was conducted with institutional approval from the 12 participating centers in North America and Europe. Data were recorded for the first post-transplant year. The log-rank test assessed for the association between PFI and survival. Associations between time to PFI and risk factors were assessed by Cox proportional hazards models.Of the 555 subjects transplanted, 58 (10.5%) had 62 proven (Candida, Aspergillus or other) or probable (Aspergillus or other) PFIs within the first year post-transplant. The mean age for PFI subjects was 14.0 years vs 11.4 years for non-PFI subjects (p < 0.01). Candida and Aspergillus species were recovered equally for proven disease. Comparing subjects with PFI (n = 58) vs those without (n = 404), pre-transplant colonization was associated with PFI (hazard ratio [HR] 2.0; 95% CI 0.95 to 4.3, p = 0.067). Cytomegalovirus (CMV) mismatch, tacrolimus-based regimen and age >15 years were associated with PFI (p < 0.05). PFI was associated with any prior rejection higher than Grade A2 (HR 2.1; 95% CI 1.2 to 3.6). Cystic fibrosis, induction therapy, transplant era and type of transplant were not associated with PFI. PFI was independently associated with decreased 12-month survival (HR 3.9, 95% CI 2.2 to 6.8).Risk factors for PFI include Grade A2 rejection, repeated acute rejection, CMV-positive donor, tacrolimus-based regimen and pre-transplant colonization.
View details for DOI 10.1016/j.healun.2008-03-010
View details for Web of Science ID 000256597500012
View details for PubMedID 18503966
View details for PubMedCentralID PMC2447528
Profound functional and signaling changes in viable inflammatory neutrophils homing to cystic fibrosis airways
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
2008; 105 (11): 4335-4339
Blood neutrophils recruited to cystic fibrosis (CF) airways are believed to be rapidly killed by resident bacteria and to passively release elastase and other toxic by-products that promote disease progression. By single-cell analysis, we demonstrate that profound functional and signaling changes readily occur within viable neutrophils recruited to CF airways, compared with their blood counterparts. Airway neutrophils have undergone conventional activation, as shown by decreased intracellular glutathione, increased lipid raft assembly, surface mobilization of CD11b+ and CD66b+ granules, and increased levels of the cytoskeleton-associated phospho-Syk kinase. Unexpectedly, they also mobilize to the surface CD63+ elastase-rich granules, usually confined intracellularly, and lose surface expression of CD16 and CD14, both key receptors in phagocytosis. Furthermore, they express CD80, major histocompatibility complex type II, and the prostaglandin D2 receptor CD294, all normally associated with other lineages, which reflects functional reprogramming. This notion is reinforced by their decreased total phosphotyrosine levels, mirroring a postactivated stage, and increased levels of the phospho-S6 ribosomal protein, a key anabolic switch. Thus, we identified a subset of neutrophils within CF airways with a viable but dysfunctional phenotype. This subset provides a possible therapeutic target and indicates a need to revisit current paradigms of CF airway disease.
View details for DOI 10.1073/pnas.0712386105
View details for Web of Science ID 000254263300048
View details for PubMedID 18334635
View details for PubMedCentralID PMC2393742
Variability in immunization guidelines in children before and after lung transplantation
2007; 11 (8): 882-887
Lung transplant candidates and recipients are at high risk of infections from vaccine-preventable diseases. However, well-established guidelines neither exist for pre- and post-transplant vaccination nor do monitoring guidelines for pediatric lung transplant recipients. To ascertain the current vaccination and monitoring practices of pediatric lung transplant centers, a self-administered questionnaire was distributed to the 18 pediatric lung transplant centers within the International Pediatric Lung Transplant Collaborative in April 2006. Sixteen of 18 centers (89%) surveyed responded. Pretransplant, national vaccination guidelines are followed. Eleven centers reported following standardized vaccination guidelines post-transplant. Vaccines were more commonly provided by the primary-care physician pretransplant (69%) rather than post-transplant (38%). Post-transplant, 50% of the centers recommend live vaccines for household contacts but not for the transplant recipient. Pretransplant monitoring of response to prior vaccination was performed inconsistently except for varicella (88%). Only 44% of the transplant centers measure for response to vaccination post-transplant, mostly hepatitis B. Current vaccination practices of pediatric lung transplant centers are heterogeneous. The lung transplant community would be well served by studies designed to evaluate the efficacy of vaccinations in this population.
View details for DOI 10.1111/j.1399-3046.2007.00759.x
View details for Web of Science ID 000250520100008
View details for PubMedID 17976123
Novel tobramycin inhalation powder in cystic fibrosis subjects: Pharmacokinetics and safety
2007; 42 (4): 307-313
Aerosolized antibiotics are associated with a high treatment burden that can result in non-adherence to chronic therapy. We evaluated the pharmacokinetics (PK) and safety of tobramycin inhalation powder (TIP), a novel dry-powder formulation designed to deliver a high payload of tobramycin topically to the lungs for management of chronic Pseudomonas aeruginosa infections. This was a multi-center, open-label, sequential-cohort, single-dose, dose-escalation study using the standard 300 mg dose of tobramycin solution for inhalation (TSI) as an active control. Subjects were randomized to TIP or TSI in a 3:1 ratio in each of five cohorts. Measurements included serum and sputum tobramycin concentrations, administration time, serum chemistries, acute change in lung function, and adverse events (AEs). Out of 90 randomized subjects, 86 had data for safety analysis; and 84 had data for PK analysis. Serum tobramycin PK profiles were similar for TIP and TSI. Four capsules of 28 mg TIP (total tobramycin dose 112 mg) produced comparable systemic exposure to 300 mg TSI, in less than one-third the administration time. The most common AEs associated with TIP were cough (20%) and dysgeusia (17%). TIP allows for faster and more efficient pulmonary delivery of tobramycin than TSI and has a safety profile that supports continued clinical investigation. The increased rate of local respiratory tract irritation noted with TIP is not unexpected with a high-payload powder formulation. The development of dry powder inhaled antibiotics may represent an important advance in the treatment of chronic lung infections.
View details for DOI 10.1002/ppal.20594
View details for Web of Science ID 000245575100001
View details for PubMedID 17352404
Risk factors for small bowel bacterial overgrowth in cystic fibrosis
JOURNAL OF PEDIATRIC GASTROENTEROLOGY AND NUTRITION
2007; 44 (2): 212-218
The purpose of this study was to determine the prevalence of small bowel bacterial overgrowth in patients with pancreatic-insufficient cystic fibrosis (CF) compared with age-matched controls and to identify potential risk factors for small bowel bacterial overgrowth.Fifty patients, 25 pancreatic-insufficient CF study patients (mean age, 17 y) and 25 gastrointestinal clinic control patients (mean age, 15 y), completed a glucose-hydrogen breath test after an overnight fast. Study patients completed a quality-of-life questionnaire modified from the Cystic Fibrosis Questionnaire. The medical history of each patient was compared with breath test results. A positive breath test was defined as a fasting hydrogen > or =15 ppm or a rise of > or =10 ppm hydrogen over baseline during the test.The prevalence of positive breath tests was higher in the CF study group (56%) than in the control group (20%) (P = 0.02). The mean fasting hydrogen levels of patients in the study and control groups were 22 and 5 ppm (P = 0.0001). The mean questionnaire scores were not significantly different between breath test-positive and -negative study patients. The use of azithromycin was associated with an increased risk of a positive breath test. Use of laxatives and inhaled ipratropium was associated with a decreased risk of a positive breath test.Patients with CF were more likely to have elevated fasting hydrogen levels compared with controls. This suggests a high prevalence of small bowel bacterial overgrowth in CF patients. Medications commonly used by CF patients may influence intestinal health.
View details for Web of Science ID 000243851900011
View details for PubMedID 17255834
American society of transplantation executive summary on pediatric lung transplantation
AMERICAN JOURNAL OF TRANSPLANTATION
2007; 7 (2): 285-292
Lung transplantation in children poses distinctly different challenges from those seen in the adult population. This consensus statement reviews the experience in the field of pediatric lung transplantation and highlights areas that deserve further investigation.
View details for DOI 10.1111/j.1600-6143.2006.01612.x
View details for Web of Science ID 000243440100005
View details for PubMedID 17109726
High-dose oral N-acetylcysteine, a glutathione prodrug, modulates inflammation in cystic fibrosis
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
2006; 103 (12): 4628-4633
Neutrophilic airway inflammation is a hallmark of cystic fibrosis (CF). As high oxidant producers, airway neutrophils contribute largely to the systemic redox imbalance seen in CF. In turn, this chronic and profound imbalance can impact circulating neutrophils before their migration into airways. Indeed, in 18 CF patients with stable disease, blood neutrophils were readily deficient in the pivotal antioxidant glutathione (P = 0.003, compared with 9 healthy controls). In a phase 1 study, this deficiency was improved (P = 0.025) by the glutathione prodrug N-acetylcysteine, given orally in high doses (0.6 to 1.0 g three times daily, for 4 weeks). This treatment was safe and markedly decreased sputum elastase activity (P = 0.006), the strongest predictor of CF pulmonary function. Consistently, neutrophil burden in CF airways was decreased upon treatment (P = 0.003), as was the number of airway neutrophils actively releasing elastase-rich granules (P = 0.005), as measured by flow cytometry. Pulmonary function measures were not improved, as expected with short-term treatment. After excluding data from subjects without baseline airway inflammation, positive treatment effects were more pronounced and included decreased sputum IL-8 levels (P = 0.032). Thus, high-dose oral N-acetylcysteine has the potential to counter the intertwined redox and inflammatory imbalances in CF.
View details for DOI 10.1073/pnas.0511304103
View details for Web of Science ID 000236362600055
View details for PubMedID 16537378
View details for PubMedCentralID PMC1450222
Mutations in the beta-subunit of the epithelial Na+ channel in patients with a cystic fibrosis-like syndrome
HUMAN MOLECULAR GENETICS
2005; 14 (22): 3493-3498
Cystic fibrosis (CF) is an autosomal recessive disorder of Cl(-) and Na(+) transport. The vast majority of CF patients have deleterious mutations in an epithelial Cl(-) channel called the CF transmembrane conductance regulator (CFTR). In contrast, defects in the epithelial Na(+) channel (SCNN1) have been associated with phenotypes dominated by renal disease (systemic pseudohypoaldosteronism type I and Liddle syndrome). We report two non-classic CF patients without CFTR mutations who have novel deleterious mutations in the beta-subunits of SCNN1 in the absence of overt renal disease.
View details for DOI 10.1093/hmg/ddi374
View details for Web of Science ID 000233216600015
View details for PubMedID 16207733
- Does bacterial colonization play a role in acute respiratory failure in chronic obstructive pulmonary disease? CRITICAL CARE MEDICINE 2005; 33 (9): 2130-2131
Evaluation of exposure and health care worker response to nebulized administration of tgAAVCF to patients with cystic fibrosis
ANNALS OF OCCUPATIONAL HYGIENE
2004; 48 (8): 673-681
A study was conducted to assess health care worker exposure to tgAAVCF during the aerosolized administration of this experimental gene transfer agent in clinical trials for the treatment of cystic fibrosis (CF). tgAAVCF is a recombinant adeno-associated virus (AAV) genetically engineered to contain the human CF transmembrane conductance regulator cDNA. Study subjects included eight health care workers involved in the administration of tgAAVCF in a phase II study and 12 control health care workers who were involved with the treatment of CF patients, but not administration of the study drug. The exposure assessment entailed the determination of personal and area airborne tgAAVCF concentrations. In addition, serologic status of the health care workers was evaluated throughout the study for the presence of antibodies to AAV. A symptom survey was also completed by both the active and control health care workers. Air samples were analyzed by an infectivity assay (active vector) and a DNA polymerase chain reaction amplification procedure (vector DNA). Air monitoring was conducted during 13 tgAAVCF and seven placebo administrations. Active vector and vector particles were detected in four of 51 and 48 of 51 air samples collected during the administration of tgAAVCF, respectively. Based on the airborne vector particle concentration, the workers' exposure was estimated to be 0.0006% of the administered dose. At this level of exposure, the prevalence of symptoms was very low, the spectrum was similar in both study groups and did not result in any reported negative health effects.
View details for Web of Science ID 000225270100003
View details for PubMedID 15507460
Phase I trial of intranasal and endobronchial administration of a recombinant adeno-associated virus serotype 2 (rAAV2)-CFTR vector in adult cystic fibrosis patients: A two-part clinical study
HUMAN GENE THERAPY
2003; 14 (11): 1079-1088
Recombinant adeno-associated serotype 2-based vectors (rAAV2) possess a number of theoretical advantages for cystic fibrosis (CF) gene therapy because they elicit little or no inflammatory response and generally result in stable expression. rAAV2 vectors expressing the cystic fibrosis transmembrane conductance regulator (CFTR) gene have previously been shown to mediate stable correction of the CF defect in CF bronchial epithelial cells and stable expression of CFTR in rabbit and nonhuman primate models. Here we report the results of the first trial initiated with rAAV in humans, a phase I study in 25 adult and adolescent CF patients with mild to moderate lung disease. Doses of the rAAV-CFTR vector (tgAAVCF) ranging from 3 x 10(1) to 1 x 10(9) replication units (RU), which is equivalent to approximately 6 x 10(4) to 2 x 10(12) DNase resistant particles (DRP), were administered to one side of the nose and to the superior segment of the lower lobe of the right lung. Several adverse events were noted prior to and/or after vector delivery, but most of them appeared to be related to the endogenous CF lung disease or a result of the bronchoscopic procedures. Only one of the serious events was judged to be possibly vector-related (based on temporal association), and this event was a pulmonary exacerbation very similar to several others experienced by the same subject in the three months preceding vector delivery. Vector shedding was minimal throughout the study, and serum-neutralizing antibodies were detected after vector delivery to subjects in the highest dosage cohorts. Gene transfer as measured by DNA polymerase chain reaction (PCR) was not observed until cohort 10 in nasal and bronchial epithelia. Sporadic low-level copy numbers suggested gene transfer of anywhere from 0.002 copies per cell up to 0.5 copies per cell was possible; however, DNA PCR was positive in lungs prior to direct dosing suggesting aspiration from the nasal dosing. These data indicate the need for continued evaluation of rAAV-CFTR vectors in additional clinical trials.
View details for Web of Science ID 000184205600004
View details for PubMedID 12885347
A phase II, double-blind, randomized, placebo-controlled clinical trial of tgAAVCF using maxillary sinus delivery in patients with cystic fibrosis with antrostomies
HUMAN GENE THERAPY
2002; 13 (11): 1349-1359
tgAAVCF, an adeno-associated cystic fibrosis transmembrane conductance regulator (CFTR) viral vector/gene construct, was administered to 23 patients in a Phase II, double-blind, randomized, placebo-controlled clinical trial. For each patient, a dose of 100,000 replication units of tgAAVCF was administered to one maxillary sinus, while the contralateral maxillary sinus received a placebo treatment, thereby establishing an inpatient control. Neither the primary efficacy endpoint, defined as the rate of relapse of clinically defined, endoscopically diagnosed recurrent sinusitis, nor several secondary endpoints (sinus transepithelial potential difference [TEPD], histopathology, sinus fluid interleukin [IL]-8 measurements) achieved statistical significance when comparing treated to control sinuses within patients. One secondary endpoint, measurements of the anti-inflammatory cytokine IL-10 in sinus fluid, was significantly (p < 0.03) increased in the tgAAVCF-treated sinus relative to the placebo-treated sinus at day 90 after vector instillation. The tgAAVCF administration was well tolerated, without adverse respiratory events, and there was no evidence of enhanced inflammation in sinus histopathology or alterations in serum-neutralizing antibody titer to adeno-associated virus (AAV) capsid protein after vector administration. In summary, this Phase II trial confirms the safety of tgAAVCF but provides little support of its efficacy in the within-patient controlled sinus study. Various potentially confounding factors are discussed.
View details for Web of Science ID 000177015400009
View details for PubMedID 12162817
Paradoxical vocal cord motion in a child presenting with cyanosis and respiratory failure.
Pediatric critical care medicine
2002; 3 (2): 185-186
View details for PubMedID 12780992
Clinical infection control in gene therapy: A multidisciplinary conference
INFECTION CONTROL AND HOSPITAL EPIDEMIOLOGY
2000; 21 (10): 659-673
Gene therapy is being studied for the treatment of a variety of acquired and inherited disorders. Retroviruses, adenoviruses, poxviruses, adeno-associated viruses, herpesviruses, and others are being engineered to transfer genes into humans. Treatment protocols using recombinant viruses are being introduced into clinical settings. Infection control professionals will be involved in reviewing the safety of these agents in their clinics and hospitals. To date, only a limited number of articles have been written on infection control in gene therapy, and no widely available recommendations exist from federal or private organizations to guide infection control professionals. The goals of the conference were to provide a forum where gene therapy experts could share their perspectives and experience with infection control in gene therapy and to provide an opportunity for newcomers to the field to learn about issues specific to infection control in gene therapy. Recommendations for infection control in gene therapy were proposed.
View details for Web of Science ID 000089872900011
View details for PubMedID 11083185
Apnea and gastroesophageal reflux in preterm and term infants: A retrospective study
INT PEDIATRIC RESEARCH FOUNDATION, INC. 2000: 407A
View details for Web of Science ID 000086155302405
Cisapride decreases gastroesophageal reflux in 'symptomatic' preterm infants
INT PEDIATRIC RESEARCH FOUNDATION, INC. 2000: 407A
View details for Web of Science ID 000086155302406
Safety and biological efficacy of an adeno-associated virus vector cystic fibrosis transmembrane regulator (AAV-CFTR) in the cystic fibrosis maxillary sinus
11th Annual North American Cystic Fibrosis Conference
JOHN WILEY & SONS INC. 1999: 266–74
The host immune response and low vector efficiency have been key impediments to effective cystic fibrosis transmembrane regulator (CFTR) gene transfer for cystic fibrosis (CF). An adeno-associated virus vector (AAV-CFTR) was used in a phase I dose-escalation study to transfer CFTR cDNA into respiratory epithelial cells of the maxillary sinus of 10 CF patients.A prospective, randomized, unblinded, dose-escalation, within-subjects, phase I clinical trial of AAV-CFTR was conducted.Ten patients with previous bilateral maxillary antrostomies were treated.Safety, gene transfer as measured by semiquantitative polymerase chain reaction (PCR), and sinus transepithelial potential difference (TEPD) were measured.The highest level of gene transfer was observed in the range of 0.1-1 AAV-CFTR vector copy per cell in biopsy specimens obtained 2 weeks after treatment. When tested, persistence was observed in one patient for 41 days and in another for 10 weeks. Dose-dependent changes in TEPD responses to pharmacologic intervention were observed following treatments. Little or no inflammatory or immune responses were observed.AAV-CFTR administration to the maxillary sinus results in successful, dose-dependent gene transfer to the maxillary sinus and alterations in sinus TEPD suggestive of a functional effect, with little or no cytopathic or host immune response. Further study is warranted for AAV vectors as they may prove useful for CFTR gene transfer and other in vivo gene transfer therapies. A prospective, randomized, double-blind, placebo-controlled, within-subjects, phase II clinical trial of the effect AAV-CFTR on clinical recurrence of sinusitis will determine the clinical efficacy of AAV gene therapy for CF.
View details for Web of Science ID 000078432500017
View details for PubMedID 10890777
- A phase I/II study of tgAAV-CF for the treatment of chronic sinusitis in patients with cystic fibrosis HUMAN GENE THERAPY 1998; 9 (6): 889-909
Safety of single-dose administration of an adenoassociated virus (AAV)-CFTR vector in the primate lung
1996; 3 (8): 658-668
Gene therapy for cystic fibrosis (CF) would ideally be accomplished with a vector capable of long-term expression of the cystic fibrosis transmembrane conductance regulator (CFTR) in the absence of a host inflammatory response. Recombinant adeno-associated virus (AAV)-CFTR vectors possess these characteristics in rabbits. Because the utility of AAV vectors as gene transfer agents has only been recognized recently, AAV vector-mediated transduction has never been modeled in a primate host, which is an important step before its use in humans. In order to test the safety and biological activity of AAV-CFTR, single doses of AAV-CFTR vector were administered by fiberoptic bronchoscopy to the posterior basal segment of the right lower lobe (RLL) of the lungs of 10 rhesus macaques with four matched vehicle-treated controls. Animals were followed for 10, 21, 90 or 180 days following vector instillation. Vector DNA transfer occurred in bronchial epithelial cells in the RLL of each animal that received vector as assessed by in situ DNA PCR. Vector mRNA was detectable for 180 days after administration as detected by RT-PCR and by RNase protection assay. Safety of vector administration was determined by measurements of pulmonary mechanics, arterial blood gas analysis, chest radiographs, and bronchoalveolar lavage (BAL) fluid analysis including cell count and quantification of inflammatory cytokines. Gross and microscopic pathologic examination were also performed. There was no evidence of inflammation or other toxicity, although vector DNA was found in extrapulmonary organs of some animals. These results indicate that transduction of the primate airway epithelium with the AAV-CFTR mediates long-term CFTR cDNA transfer and is relatively safe.
View details for Web of Science ID A1996VB53600002
View details for PubMedID 8854091
- A phase I study of an adeno-associated virus-CFTR gene vector in adult CF patients with mild lung disease HUMAN GENE THERAPY 1996; 7 (9): 1145-1159
In vivo model of adeno-associated virus vector persistence and rescue
JOURNAL OF VIROLOGY
1996; 70 (5): 3235-3241
Gene therapy vectors based on human DNA viruses could be mobilized or rescued from individuals who are subsequently infected with the corresponding wild-type (wt) helper viruses. This phenomenon has been effectively modeled in vitro with both adenovirus (Ad) and adeno-associated virus (AAV) vectors but has not previously been studied in vivo. In the current study, we have developed an in vivo model to study the interactions of a recombinant AAV vector (AAV-CFTR) with wt AAV type 2 (AAV2) and a host range mutant Ad (Ad2HR405) for which monkey cells are permissive (D.E.Brough, S.A.Rice, S.Sell, and D.F.Klessig, J. Virol. 55:206-212, 1985). AAV-CFTR was administered to the respiratory epithelium of the nose or lung of rhesus macaques. Primary cells were harvested from the infusion site at time points up to 3 months after vector administration to confirm vector DNA persistence. Vector DNA was present in episomal form and could be rescued in vitro only by addition of wt AAV2 and Ad. In in vivo rescue studies, vector was administered before or after wt-AAV2 and Ad2HR405 infection, and the shedding of AAV-CFTR was examined. Ad2HR405 and wt-AAV2 infections were established in the nose with concomitant administration. wt-AAV2 replication occurred in the lung when virus was administered directly at a high titer to the lower respiratory tract. AAV-CFTR vector rescue was also observed in the latter setting. Although these studies were performed with small numbers of animals within each group, it appears that AAV-CFTR DNA persists in the primate respiratory tract and that this model may be useful for studies of recombinant AAV vector rescue.
View details for Web of Science ID A1996UF24700065
View details for PubMedID 8627804
View details for PubMedCentralID PMC190187
ALVEOLAR STEM-CELL TRANSDUCTION BY AN ADENOASSOCIATED VIRAL VECTOR
1995; 2 (9): 623-631
In inherited disorders such as surfactant protein deficiencies or cystic fibrosis (CF), where lung damage develops progressively after birth, gene replacement is best accomplished in the neonatal period. We use the adeno-associated virus (AAV) as a vector for gene transfer in the newborn rabbit lung where stem cells are activated for lung growth and differentiation. AAV-mediated gene transfer as assayed by lacZ gene expression occurred preferentially in alveoli in the alveolar epithelial progenitor cell, the type II cell, and in the large airway tracheobronchial basal and ciliated cells. Cell proliferation was confirmed by 5-bromo-deoxyuridine (BRDU) labeling in regions undergoing alveolarization and airway branch points. Regions of cell proliferation coincided with areas of significant lacZ expression. Thus, dividing and differentiating cells can be targeted by AAVlacZ delivery to newborn lung.
View details for Web of Science ID A1995TC43400004
View details for PubMedID 8548551
- GENE-THERAPY VECTORS AS DRUG-DELIVERY SYSTEMS CLINICAL PHARMACOKINETICS 1995; 28 (3): 181-189
- HEMOTHORAX IN A CHILD AS A RESULT OF COSTAL EXOSTOSIS PEDIATRICS 1994; 93 (3): 523-525
STABLE IN-VIVO EXPRESSION OF THE CYSTIC-FIBROSIS TRANSMEMBRANE CONDUCTANCE REGULATOR WITH AN ADENOASSOCIATED VIRUS VECTOR
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
1993; 90 (22): 10613-10617
Adeno-associated virus (AAV) vectors expressing the normal cystic fibrosis transmembrane conductance regulator (CFTR) cDNA complement the cystic fibrosis (CF) defect in vitro. Unlike other DNA virus vectors, AAV is a stably integrating virus, which could make possible long-term in vivo complementation of the CF defect in the airway epithelium. We report AAV-CFTR gene transfer and expression after infection of primary CF nasal polyp cells and after in vivo delivery of AAV-CFTR vector to one lobe of the rabbit lung through a fiberoptic bronchoscope. In the rabbit, vector DNA could be detected in the infected lobe up to 6 months after administration. A 26-amino acid polypeptide sequence unique to the recombinant AAV-CFTR protein was used to generate both oligonucleotide probes and a polyclonal antibody which allowed the unambiguous identification of vector RNA and CFTR protein expression. With these reagents, CFTR RNA and protein were detected in the airway epithelium of the infected lobe for up to 6 months after vector administration. AAV vectors do, therefore, efficiently promote in vivo gene transfer to the airway epithelium which is stable over several months. These findings indicate that AAV-CFTR vectors could potentially be very useful for gene therapy.
View details for Web of Science ID A1993MH32200042
View details for PubMedID 7504271
View details for PubMedCentralID PMC47827
PROTEINS BUT NOT AMINO-ACIDS, CARBOHYDRATES, OR FATS STIMULATE CHOLECYSTOKININ SECRETION IN THE RAT
AMERICAN JOURNAL OF PHYSIOLOGY
1986; 251 (2): G243-G248
Because of prior difficulties in measuring plasma cholecystokinin (CCK) levels, it has not been established which components of food stimulate CCK secretion in rats. In the present study, we used a sensitive and specific bioassay for measuring plasma CCK and determined the effects of proteins, protein hydrolysates, amino acids, fats, starch, and glucose on CCK secretion in this species. Intact proteins were the only stimulants of CCK release. Solutions of 18% casein and 0.2% soybean trypsin inhibitor caused prompt increases in plasma CCK levels from 0.5 +/- 0.2 to 7.9 +/- 1.9 and 8.0 +/- 2.0 pM, respectively, within 5 min of orogastric administration. The proteins lactalbumin and bovine serum albumin caused smaller elevations in circulating CCK. In contrast, hydrolysates of casein and lactalbumin and the amino acids L-phenylalanine and L-tryptophan did not stimulate CCK release. In addition, plasma CCK levels did not increase with the feeding of fat, starch, or glucose. The ability of proteins to stimulate CCK secretion paralleled their ability to inhibit trypsin activity in vitro. Furthermore, the plasma CCK response to casein was completely abolished by the simultaneous administration of trypsin. These studies indicate that proteins are the major food stimulants of CCK release in the rat and that the effects of proteins are related to inhibition of intraluminal protease activity.
View details for Web of Science ID A1986D598500053
View details for PubMedID 3740265
REGULATION OF GASTRIC-EMPTYING IN HUMANS BY CHOLECYSTOKININ
JOURNAL OF CLINICAL INVESTIGATION
1986; 77 (3): 992-996
In the present study we used a bioassay system for measuring plasma cholecystokinin (CCK) to evaluate whether CCK has a physiologic role in regulating gastric emptying in humans. Plasma CCK levels and gastric emptying after ingestion of a mixed liquid meal were determined in five normal male volunteers. Fasting CCK levels averaged 0.8 +/- 0.1 pM and increased to 6.5 +/- 1.0 pM within 10 min of drinking the mixed meal. CCK levels remained elevated for up to 90 min. Gastric emptying after a meal was slow; at the end of the 90 min 68% of the original volume remained in the stomach. The rate of gastric emptying of water was then measured in the same individuals with a simultaneous infusion of either saline, or one of two doses of CCK (12 pmol/kg per h and 24 pmol/kg per h). With the saline infusion, plasma CCK levels did not increase above basal and gastric contents emptied rapidly. At the end of 90 min only 7% of the original volume remained in the stomach. The lower dose of CCK resulted in a plasma level of 3.4 pM which both reproduced the average postprandial plasma level and caused a significant delay in gastric emptying. The higher dose of CCK achieved plasma levels of 8 pM and resulted in a delay in gastric emptying that was similar to that seen with the mixed meal. Since exogenous CCK at concentrations which occur postprandially delays gastric emptying, we conclude that CCK is a physiologic regulator of gastric emptying.
View details for Web of Science ID A1986A542900043
View details for PubMedID 3949984
View details for PubMedCentralID PMC423501