Faculty Bibliography

Rationale: Asthma is a chronic inflammatory disease of the airway influenced by genetic variants, environmental factors, and their interactions. Variants of the interleukin-1 receptor antagonist (IL1RN) gene, encoding an anti-inflammatory cytokine, are associated with asthma. We investigated the gene-environment interactions of childhood environmental tobacco smoke (ETS) exposure with IL1RN genotypes of single-nucleotide polymorphisms (SNPs) for asthma susceptibility in an urban adult population. Methods: DNA samples from the NYU/Bellevue Asthma Registry (NYUBAR) were genotyped for six tag SNPs in IL1RN in 259 asthma cases and 182 unrelated healthy controls. Information about childhood ETS exposure and age at onset for doctor diagnosed asthma were collected. Logistic regression was used to assess associations of IL1RN variants (alleles, genotypes, haplotypes) with asthma, adjusting for population admixture and other factors and covariates. Gene-environment interactions (GEIs) for the risk of asthma and early onset asthma were evaluated via stratification on childhood ETS exposure (with/without) and on IL1RN SNP genotypes (rare/common), respectively. Visible patterns of GEIs were displayed using stratified Kaplan-Meier curves for age of asthma onset. Results: Allelic and genotypic association analyses of the IL1RN tag SNPs and asthma susceptibility for the NYUBAR population as a whole resulted in findings that were in accordance with previous publications with protective effects of rare genotypes of candidate SNPs. Stratified analyses based on ETS exposure status indicated that the protective effects of rare genotypes of tag SNPs (e.g. GG in SNP rs392503) were significant only within the groups without childhood ETS exposure (OR=0.179, P=0.009); in contrast, there was a significantly elevated risk for early onset asthma among rare-genotype carriers with ETS exposure (OR=4.02, P=0.019). Importantly, whereas childhood ETS exposure was a risk factor for early onset asthma across all genotype groups of IL1RN (OR=1.74, P=0.03), it dramatically increased the risk within the group carrying rare SNP genotypes of IL1RN with the observed odds ratios (ORs) in the range between 7.3 and 9.1 (Fisher exact P-values<0.05). Conclusion: Analysis of gene-environment interactions between ETS exposure and IL1RN variants indicated that, at population level, childhood ETS exposure disrupted the protective effect of rare tag SNP genotypes of IL1RN for asthma and turned them into high risk genotypes for early onset asthma

INTRODUCTION: We have previously shown improvement in spirometry parameters in symptomatic WTC dust exposed community members enrolled in the WTC Environmental Health Center treatment program. Additionally, impulse oscillometry (IOS) has demonstrated evidence for distal lung injury not apparent on spirometry. We hypothesize that longitudinal change of spirometry will differ based on presence or absence of distal airway injury and its response to bronchodilator at baseline. METHODS: 810 patients were identified with more than one spirometry and IOS assessment. IOS parameters included resistance at 5 and 20Hz (R₅ and R₂₀) and frequency dependence of resistance assessed as the difference between these parameters (R_5-20). Linear mixed effects modeling evaluated longitudinal changes in IOS parameters, FVC and FEV₁ for the entire population. Separate models were fit for subgroups categorized based on normal vs. abnormal baseline spirometry and normal vs. abnormal baseline IOS (R₅>3.96 cmH2O/L/s). Analyses were adjusted for confounding factors (age, gender, BMI, race/ethnicity, smoking, exposure category and dust cloud exposure). RESULTS: Mean age was 50yr. Patients were mostly female (52%) and had diverse race/ethnicity. At baseline, mean FVC was 91+/-17% predicted and FEV₁ was 88+/-18% predicted. A normal spirometry pattern was noted in the majority (67%; n=542). Despite normal spirometry, IOS revealed abnormalities in 67% (n=364). Longitudinal analysis of IOS parameters (R₅, R₂₀, R_5-20) over time revealed no significant trends for the entire population and for subgroups categorized by baseline spirometry pattern. In contrast, the longitudinal change in spirometry variables differed based on presence of IOS abnormality. In patients with normal spirometry, FEV₁ increased more rapidly in patients with abnormal baseline IOS compared to those with normal IOS (0.76 vs. 0.52 % predicted/yr; Table 1). For patients with abnormal baseline spirometry, FVC increased more rapidly in the abnormal vs. normal IOS patients (1.73 vs. 1.02 % predicted/yr). Patients with IOS response to bronchodilator (highest quartile for improvement of R₅ post bronchodilator) demonstrated a more rapid longitudinal increase in FEV₁ compared with patients without bronchodilator response (lowest quartile)(0.88 vs. 0.53 % predicted/yr,; Table 2). CONCLUSIONS: Spirometry parameters demonstrated improvement over time, while improvement in IOS parameters was not evident, suggesting potential irreversible injury in the distal lung. However, assessment of baseline distal airway function and its acute response to bronchodilator predicted longitudinal response of spirometry in patients enrolled in a treatment program. (Table Presented)

OBJECTIVE: : The course of lung function in community members exposed to World Trade Center (WTC) dust and fumes remains undefined. We studied longitudinal spirometry among patients in the WTC Environmental Health Center (WTCEHC) treatment program. METHODS: : Observational study of 946 WTCEHC patients with repeated spirometry measures analyzed on the population as a whole and stratified by smoking status, initial spirometry pattern, and WTC-related exposure category. RESULTS: : Improvement in forced vital capacity (54.4 mL/yr; 95% confidence interval, 45.0 to 63.8) and forced expiratory volume in 1 second (36.8 mL/yr; 95% confidence interval, 29.3 to 44.3) was noted for the population as a whole. Heavy smokers did not improve. Spirometry changes differed depending on initial spirometry pattern and exposure category. CONCLUSION: : These data demonstrate spirometry improvement in select populations suggesting reversibility in airway injury and reinforcing the importance of continued treatment.

This is a concise review on Interleukin (IL)-13 and the evolution of asthma therapy, from discovery of the molecule, the identification of its pathogenic role in animal models of asthma, to the development of clinically successful neutralizing agents. The translational path from basic research to clinical application was not sequential as expected but random with respect to the tools (molecular & cell biology, animal models, human studies) used and to the application of academic versus industry research. The experiences with the development of neutralizing anti-IL-13 reagents emphasize the need for inclusion of a biomarker assay in the clinical trials that both identifies individuals that actually have aberrant expression of the pathway of interest and allows determining whether the target of interest is neutralized.

Objectives. We assessed associations between new-onset (post-September 11, 2001 [9/11]) lower respiratory symptoms reported on 2 surveys, administered 3 years apart, and acute and chronic 9/11-related exposures among New York City World Trade Center-area residents and workers enrolled in the World Trade Center Health Registry. Methods. World Trade Center-area residents and workers were categorized as case participants or control participants on the basis of lower respiratory symptoms reported in surveys administered 2 to 3 and 5 to 6 years after 9/11. We created composite exposure scales after principal components analyses of detailed exposure histories obtained during face-to-face interviews. We used multivariate logistic regression models to determine associations between lower respiratory symptoms and composite exposure scales. Results. Both acute and chronic exposures to the events of 9/11 were independently associated, often in a dose-dependent manner, with lower respiratory symptoms among individuals who lived and worked in the area of the World Trade Center. Conclusions. Study findings argue for detailed assessments of exposure during and after events in the future from which potentially toxic materials may be released and for rapid interventions to minimize exposures and screen for potential adverse health effects.

PURPOSE OF REVIEW: Guidelines suggest that asthma medication should be reduced once asthma control is sustained. Moderate-dose inhaled corticosteroids (ICS) can typically be reduced, but questions remain about the lowest effective ICS dose and the role of non-ICS controllers in treatment reduction. Long-acting beta agonist (LABA) safety concerns have created controversy about how to step down patients on ICS/LABA therapy. This review will focus on the current status of these issues. RECENT FINDINGS: Intermittent ICS treatment, often in fixed combination with short-acting beta agonist, is an emerging strategy for control of mild asthma. Addition of leukotriene modifiers, LABAs, and omalizumab to ICS can allow for reduced ICS dosing. Doses of ICS that control symptoms may be inadequate to control exacerbations. Reducing ICS dose before discontinuing LABAs may be the more effective approach for patients on combination therapy. SUMMARY: Use of non-ICS controllers allows for ICS dose reduction with superior outcomes. Tapering of ICS prior to LABA discontinuation may be the favored approach for patients on ICS/LABA therapy, but an understanding of long-term outcomes and further safety data are required. The lowest ICS dose that adequately controls both asthma impairment and risk remains to be determined

RATIONALE: Identification and characterization of asthma phenotypes are challenging due to disease complexity and heterogeneity. The Severe Asthma Research Program (SARP) used unsupervised cluster analysis to define 5 phenotypically distinct asthma clusters that they replicated using 3 variables in a simplified algorithm. We evaluated whether this simplified SARP algorithm could be used in a separate and diverse urban asthma population to recreate these 5 phenotypic clusters. METHODS: The SARP simplified algorithm was applied to adults with asthma recruited to the New York University/Bellevue Asthma Registry (NYUBAR) to classify patients into five groups. The clinical phenotypes were summarized and compared. RESULTS: Asthma subjects in NYUBAR (n = 471) were predominantly women (70%) and Hispanic (57%), which were demographically different from the SARP population. The clinical phenotypes of the five groups generated by the simplified SARP algorithm were distinct across groups and distributed similarly to those described for the SARP population. Groups 1 and 2 (6 and 63%, respectively) had predominantly childhood onset atopic asthma. Groups 4 and 5 (20%) were older, with the longest duration of asthma, increased symptoms and exacerbations. Group 4 subjects were the most atopic and had the highest peripheral eosinophils. Group 3 (10%) had the least atopy, but included older obese women with adult-onset asthma, and increased exacerbations. CONCLUSIONS: Application of the simplified SARP algorithm to the NYUBAR yielded groups that were phenotypically distinct and useful to characterize disease heterogeneity. Differences across NYUBAR groups support phenotypic variation and support the use of the simplified SARP algorithm for classification of asthma phenotypes in future prospective studies to investigate treatment and outcome differences between these distinct groups. TRIAL REGISTRATION: Clinicaltrials.gov NCT00212537.

Introduction: Ambient pollutants upregulate cytokines involved in mucosal immune responses. We recently demonstrated that diesel exhaust particle (DEP)-treated human bronchial epithelial cells (HBEC) upregulated myeloid dendritic cell maturation and Th2 polarization via HBEC-derived thymic stromal lymphopoietin (TSLP), suggesting that TSLP links environmental exposures and airway immune responses. In airway epithelial cells, TSLP is regulated in part by nuclear factor (NF)-kappaB activation, but additional regulatory signals remain unclear. Since a correlation of miR-375 and TSLP expression has been described in the murine gut, we hypothesized that hsa-miR-375 regulated TSLP expression in human primary HBEC. Methods: Primary human bronchial epithelial cells (pHBEC) were treated with defined stimuli including DEP (3mug/cm2) and total RNA was isolated (6h). Levels of mRNA or microRNA were measured using qRT-PCR and normalized against housekeeping genes (GAP-DH and RNU6-2 respectively). For transfection studies, pHBEC were seeded (60% confluence) and transfected with synthetic miRNA, anti-miRNA, and respective control species (HiPerFect transfection reagent). Data were normalized to housekeeping control and expressed as fold increase compared to resting controls. Results: Exposure of pHBEC to DEP, but not to TNFalpha upregulated hsa-miR-375 (4.2+/-1.1and 1.6+/-1.2 fold, respectively). In the same samples, TSLP was induced (5.0+/-1.4 fold) by DEP and 12.1+/-2.6 fold by TNFalpha. To confirm the role of hsa-miR-375, pHBEC were transfected with synthetic miR-375, anti-miR-375, or respective miRNA controls. Transfection with hsa-miR-375 but not control, upregulated TSLP expression (1.8+/-0.4 fold). Treatment of pHBEC with DEP in the presence of transfected anti-miR-375, but not control, reduced TSLP expression (53.0+/-15.0 % reduction compared to mock transfected DEP). In contrast, transfection with anti-miR-375 failed to reduce TNFalpha induced TSLP expression. Because hsa-miR-375 was upregulated by DEP, we performed an in silico analysis for putative targets and identified the aryl hydrocarbon receptor (AhR) (Targetscan 5.1). Both DEP and ambient PM reduced AhR transcript but increased transcriptional activity (CYP1A1 expression) in pHBEC. Transfection of pHBEC with synthetic miR-375 reduced AhR transcript (80+/-35 % reduction) and upregulated TSLP. Conclusion: These data suggest a selective mechanism of TSLP regulation by DEP in pHBEC via hsa-miR-375. Since the AhR has been described to interfere with NF-kappaB activation via stabilization of the inhibitory RelB subunit, its transcript reduction by miR-375 may be a potential pathway for DEP regulation of TSLP

Introduction: Airway epithelial cell activation in asthma is associated with the production of Th2 promoting cytokines including thymic stromal lymphopoietin (TSLP). TSLP is elevated in lung biopsies of asthmatics, and we have shown upregulation in cultured human bronchial epithelial cells (HBEC) exposed to ambient particulate matter. TSLP genetic variants are associated with asthma. Sputum analysis is a noninvasive method of obtaining specific cells from the lungs in humans and may allow for isolation of HBEC for the analysis of immunomodulatory cytokines. Hypothesis: TSLP expression is increased in HBEC from induced sputum of asthmatic individuals compared to controls. Methods: Adults with asthma and normal volunteers were enrolled between 4/2011-10/2011 at New York University/Bellevue Hospital. Subjects were excluded if they had: current or past (>10 p-y) tobacco history, other lung disease, or current use of inhaled or oral corticosteroids. Asthma cases were included if spirometry demonstrated bronchodilator reversibility or methacholine hyperresponsiveness. Controls were included if spirometry was normal and methacholine challenge was negative. Blood eosinophils, total and allergen-specific IgE and exhaled nitric oxide (FeNO) were routinely obtained. Sputum was induced with hypertonic saline, treated with sputolysin, and processed for cell count and cell differentials. Sputum cells were stained with fluorophore-labeled monoclonal antibodies, formalin fixed, and discrete cell types detected by FACS. HBEC were identified by size and immunophenotype, isolated by flow sorting, and analyzed (qRT-PCR) for expression of epithelial cell markers and TSLP. Results: Seven subjects successfully underwent sputum induction for analysis (asthma n=4, control n=3). Asthma cases were slightly older than controls (35 vs 30 y) and female predominant (66 vs 50%). There was no significant difference in % predicted FEV₁ between groups but individuals with asthma were more bronchoreactive (8 vs 2% change in FEV₁). FeNO levels and % peripheral eosinophils were higher among asthmatics (52 vs 24 ppb and 3.9 vs 1.4%, respectively). HBEC purity was confirmed by qRT-PCR against cell-specific mRNA. All preparations were positive for epithelial cell markers cytokeratin-7 and E-cadherin and negative for CD11c or CD123 (dendritic and myeloid cell markers). Expression of TSLP but not cytokeratin-7 (normalized against GAPDH from the same isolate) was significantly upregulated in asthma cases compared to controls (4.6-fold, p<0.04). Conclusions: Our data show in situ upregulation of TSLP mRNA in bronchial epithelial cells isolated by multicolor FACS from the induced sputum of individuals with asthma