Faculty Bibliography

BACKGROUND: The present study (1) characterizes a physiologic phenotype of restrictive dysfunction due to airway injury and (2) compares this phenotype to the phenotype of interstitial lung disease (ILD). METHODS: This is a retrospective study of 54 persistently symptomatic subjects following World Trade Center (WTC) dust exposure. Inclusion criteria were reduced vital capacity (VC), FEV1/VC > 77%, and normal chest roentgenogram. Measurements included spirometry, plethysmography, diffusing capacity of lung for carbon monoxide (Dlco), impulse oscillometry (IOS), inspiratory/expiratory CT scan, and lung compliance (n = 16). RESULTS: VC was reduced (46% to 83% predicted) because of the reduction of expiratory reserve volume (43% +/- 26% predicted) with preservation of inspiratory capacity (IC) (85% +/- 16% predicted). Total lung capacity (TLC) was reduced, confirming restriction (73% +/- 8% predicted); however, elevated residual volume to TLC ratio (0.35 +/- 0.08) suggested air trapping (AT). Dlco was reduced (78% +/- 15% predicted) with elevated Dlco/alveolar volume (5.3 +/- 0.8 [mL/mm Hg/min]/L). IOS demonstrated abnormalities in resistance and/or reactance in 50 of 54 subjects. CT scan demonstrated bronchial wall thickening and/or AT in 40 of 54 subjects; parenchymal disease was not evident in any subject. Specific compliance at functional residual capacity (FRC) (0.07 +/- 0.02 [L/cm H2O]/L) and recoil pressure (Pel) at TLC (27 +/- 7 cm H2O) were normal. In contrast to patients with ILD, lung expansion was not limited, since IC, Pel, and inspiratory muscle pressure were normal. Reduced TLC was attributable to reduced FRC, compatible with airway closure in the tidal range. CONCLUSIONS: This study describes a distinct physiologic phenotype of restriction due to airway dysfunction. This pattern was observed following WTC dust exposure, has been reported in other clinical settings (eg, asthma), and should be incorporated into the definition of restrictive dysfunction.

Air pollution contributes to acute exacerbations of asthma and the development of asthma in children and adults. Airway epithelial cells interface innate and adaptive immune responses, and have been proposed to regulate much of the response to pollutants. Thymic stromal lymphopoietin (TSLP) is a pivotal cytokine linking innate and Th2 adaptive immune disorders, and is upregulated by environmental pollutants, including ambient particulate matter (PM) and diesel exhaust particles (DEP). We show that DEP and ambient fine PM upregulate TSLP mRNA and human microRNA (hsa-miR)-375 in primary human bronchial epithelial cells (pHBEC). Moreover, transfection of pHBEC with anti-hsa-miR-375 reduced TSLP mRNA in DEP but not TNF-alpha-treated cells. In silico pathway evaluation suggested the aryl hydrocarbon receptor (AhR) as one possible target of miR-375. DEP and ambient fine PM (3 mug/cm(2)) downregulated AhR mRNA. Transfection of mimic-hsa-miR-375 resulted in a small downregulation of AhR mRNA compared with resting AhR mRNA. AhR mRNA was increased in pHBEC treated with DEP after transfection with anti-hsa-miR-375. Our data show that two pollutants, DEP and ambient PM, upregulate TSLP in human bronchial epithelial cells by a mechanism that includes hsa-miR-375 with complex regulatory effects on AhR mRNA. The absence of this pathway in TNF-alpha-treated cells suggests multiple regulatory pathways for TSLP expression in these cells.

OBJECTIVE: Prior research on the physical health of children exposed to the World Trade Center (WTC) attacks has largely relied on parental report via questionnaire. We examined the impact of clinically-reported exposures on the physical health of children who lived and/or attended school in downtown Manhattan on September 11, 2001. STUDY DESIGN: We performed a cross-sectional study of 148 patients who presented to the WTC Environmental Health Center/Survivors Health Program, and were /=1day in their home between September 11 and 18, 2001; and 25.7% reported home dust exposure. New-onset nasal/sinus congestion was reported in 52.7%, while nearly one-third reported new gastroesophageal reflux (GERD) symptoms. Prehypertension or hypertension was identified in 45.5%. Multivariable regression with exposure variables, body mass index category, and age as covariates identified strongest associations of dust cloud with spirometry (17.1% decrease in maximum midexpiratory flow). Younger children experienced increased peripheral eosinophils (+0.098% per year, p=0.023), while older children experienced more new-onset GERD (OR 1.17, p=0.004), headaches (OR 1.10, p=0.011), and prehypertension (OR 1.09, p=0.024). Home dust exposure was associated with reduced high-density lipoprotein (-10.3mg/dL, p=0.027) and elevated triglycerides (+36.3mg/dL, p=0.033). CONCLUSIONS: While these findings cannot be assumed to generalize to all children exposed to the WTC attacks, they strongly suggest the need for more extensive study of respiratory, metabolic, and cardiovascular consequences.

Background. Exposure to World Trade Center (WTC) dust and fumes is associated with the onset of asthma-like respiratory symptoms in rescue and recovery workers and exposed community members. Eosinophilic inflammation with increased lung and peripheral eosinophils has been described in subpopulations with asthma. We hypothesized that persistent asthma-like symptoms in WTC-exposed individuals would be associated with systemic inflammation characterized by peripheral eosinophils. Methods. The WTC Environmental Health Center (WTC EHC) is a treatment program for local residents, local workers, and cleanup workers with presumed WTC-related symptoms. Patients undergo a standardized evaluation including questionnaires and complete blood count. Between September 2005 and March 2009, 2462 individuals enrolled in the program and were available for analysis. Individuals with preexisting respiratory symptoms or lung disease diagnoses prior to September 2001 and current or significant tobacco use were excluded, Results. One thousand five hundred and seventeen individuals met the inclusion criteria. Patients had a mean age of 47 years, were mostly female (51%), and had a diverse race/ethnicity. Respiratory symptoms that developed after WTC dust/fume exposure and remained persistent included dyspnea on exertion (68%), cough (57%), chest tightness (47%), and wheeze (33%). A larger percentage of patients with wheeze had elevated peripheral eosinophils compared with those without wheeze (21% vs. 13%, p < .0001). Individuals with elevated peripheral eosinophils were more likely to have airflow obstruction on spirometry (16% vs. 7%, p = .0003). Conclusion. Peripheral eosinophils were associated with wheeze and airflow obstruction in a diverse WTC-exposed population. These data suggest that eosinophils may participate in lung inflammation in this population with symptoms consistent with WTC-related asthma.

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

Background: Autoantibody responses have long been associated with the severity of pulmonary arterial hypertension. Previous studies in our lab have shown that a prolonged T helper 2 (Th2) response to inhaled antigen induces severe pulmonary arterial remodeling. We have also shown that urban particulate matter (PM) from air pollution exacerbates antigen induced pulmonary arterial remodeling and pulmonary hypertension. The present study was designed to identify the role of B cells (antibody producing lymphocytes) for pulmonary hypertension induced by antigen and urban PM. Methods: The respirable fraction of urban airborne PM (urban PM2.5) was collected in New York City. Mice were primed for a Th2 response with antigen adsorbed to Alum and then challenged with soluble antigen (Ovalbumin) combined with urban PM2.5 intranasally. We determined pulmonary arterial remodeling by histology, right heart hypertrophy by measuring heart weights and right ventricular systolic pressures by heart catheterization in anaesthetized, spontaneously breathing mice. Results: In contrast to wild type, Th2 primed B cell KO mice had no significantly increased right heart weights, or right heart systolic pressures in response to intranasal antigen and urban PM2.5. Reconstitution with anti-antigen antibody restored the development of pulmonary hypertension in antigen-urban PM2.5 challenged B cell KO mice. Like wild type mice, B cell KO mice had significant pulmonary arterial remodeling that was slightly increased by reconstitution with antibody. Conclusions: Our studies suggest that antigen-specific antibody is necessary for the development of pulmonary hypertension induced by the exposure to a Th2 antigen combined with urban PM2.5. Current studies are aimed at identifying mRNA and microRNA species that are differentially expressed in the right hearts of antibody reconstituted B cell KO mice that were exposed to antigen and urban PM2.5

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

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.

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.