Flavored e-cigarettes are preferred by the majority of users yet their potential toxicity is unkn... more Flavored e-cigarettes are preferred by the majority of users yet their potential toxicity is unknown. Therefore our aim was to determine the effect of selected flavored e-cigarettes, with or without nicotine, on allergic airways disease in mice. Balb/c mice were challenged with PBS or house dust mite (HDM) (Days 0, 7, 14-18) and exposed to room air or e-cigarette aerosol for 30 min twice daily, 6 days/week from Days 0-18 (n = 8-12/group). Mice were exposed to Room Air, vehicle control (50%VG/%50PG), Black Licorice, Kola, Banana Pudding or Cinnacide without or with 12 mg/mL nicotine. Mice were assessed at 72 hours after the final HDM challenge. Compared to mice challenged with HDM and exposed to Room Air, nicotine-free Cinnacide reduced airway inflammation (p = 0.045) and increased peripheral airway hyperresponsiveness (p = 0.02), nicotine-free Banana Pudding increased soluble lung collagen (p = 0.049), with a trend towards increased airway inflammation with nicotine-free Black Licorice exposure (p = 0.089). In contrast, all e-cigarettes containing nicotine suppressed airway inflammation (p < 0.001 for all) but did not alter airway hyperresponsiveness or airway remodeling. Flavored e-cigarettes without nicotine had significant but heterogeneous effects on features of allergic airways disease. This suggests that some flavored e-cigarettes may alter asthma pathophysiology even when used without nicotine. Electronic cigarette (e-cigarette) use has dramatically increased in recent years due to its portrayal as a healthier alternative to tobacco cigarettes. E-cigarette use amongst high school aged children in the US jumped from 1.5% in 2011 to over 15% in 2015 1 . Similarly, almost 9% of 18-24 year olds are current e-cigarette users 2 . E-cigarettes administer nicotine as an aerosol, do not require tobacco combustion and therefore are assumed to remove the risks associated with tobacco cigarettes. However, e-cigarettes contain numerous toxic compounds long associated with adverse respiratory outcomes 3 . The humectant propylene glycol leads to respiratory symptoms when inhaled 4 , while nicotine adversely effects respiratory health 5 . E-cigarette liquids are also available in a seemingly limitless combination of flavor additives, with almost all users under 30 and almost 70% of older adults using flavored e-cigarettes 6 . Additionally, up to 66% of US high school aged children use e-cigarettes with only flavoring/s i.e. no nicotine 7 . However, e-cigarette flavorings have been shown to have toxic effects on human airway epithelial and immune cells . Despite the high use of flavored e-cigarettes and the potential toxicity, little is known as to the adverse effects of flavored e-cigarettes on lung function and respiratory health. Asthmatics are particularly susceptible to the effects of toxic, inhaled substances such as tobacco, with tobacco smoking asthmatics reporting worse asthma control, more unscheduled health care visits, and a greater requirement for oral corticosteroids 12 . This increased disease severity is due to both worse lung function 13 and greater severity of airway hyperresponsiveness 14 . There is currently little evidence as to the effect of e-cigarette use in patients with asthma. One study reported that asthmatic patients who transitioned from tobacco cigarette smoking to e-cigarette use reported improved asthma symptoms and lung function 15 . However, this does not address whether e-cigarettes themselves may be detrimental to asthmatics. In healthy volunteers, acute e-cigarette use can reduce lung function . Importantly, the reduction in lung function was exaggerated in patients with asthma 18 , suggesting that asthmatics may be more susceptible to the effects of e-cigarettes. However, it is unknown whether these acute effects of e-cigarettes on lung function reflect the potential effects on asthma pathophysiology.
Genome-wide association study (GWAS) is a powerful tool to identify novel pharmacogenetic single ... more Genome-wide association study (GWAS) is a powerful tool to identify novel pharmacogenetic single nucleotide polymorphisms (SNPs). Leukotriene receptor antagonists (LTRAs) are a major class of asthma medications, and genetic factors contribute to variable responses to these drugs. We used GWAS to identify novel SNPs associated with the response to the LTRA, montelukast, in asthmatics. Using genome-wide genotype and phenotypic data available from American Lung Association -Asthma Clinical Research Center (ALA-ACRC) cohorts, we evaluated 8-week change in FEV 1 related to montelukast administration in a discovery population of 133 asthmatics. The top 200 SNPs from the discovery GWAS were then tested in 184 additional samples from two independent cohorts. Twenty-eight SNP associations from the discovery GWAS were replicated. Of these, rs6475448 achieved genome-wide significance (combined P = 1.97 x 10 -09 ), and subjects from all four studies who were homozygous for rs6475448 showed increased ΔFEV 1 from baseline in response to montelukast.
Background-Asthma is a common chronic respiratory disease in children and adults. An important ge... more Background-Asthma is a common chronic respiratory disease in children and adults. An important genetic component to asthma susceptibility has long been recognized, most recently through the identification of several genes (e.g., ORMDL3, PDE4D, HLA-DQ, and TLE4) via genome-wide association studies. Objective-To identify genetic variants associated with asthma affection status using genomewide association data. Methods-We describe results from a genome-wide association study on asthma performed in 3855 subjects using a panel of 455 089 single nucleotide polymorphisms (SNPs). Result-The genome-wide association study resulted in the prioritization of 33 variants for immediate follow-up in a multi-staged replication effort. Of these, a common polymorphism (rs9272346) localizing to within 1 Kb of HLA-DQA1 (chromosome 6p21.3) was associated with asthma in adults (P-value = 2.2E-08) with consistent evidence in the more heterogeneous group of adults and children (P-value = 1.0E-04). Moreover, some genes identified in prior asthma GWAS were nominally associated with asthma in our populations. Conclusion-Overall, our findings further replicate the HLA-DQ region in the pathogenesis of asthma. HLA-DQA1 is the fourth member of the HLA family found to be associated with asthma, in addition to the previously identified HLA-DRA, HLA-DQB1 and HLA-DQA2.
Rationale: Bronchodilator response (BDR) is a measure of improvement in airway smooth muscle tone... more Rationale: Bronchodilator response (BDR) is a measure of improvement in airway smooth muscle tone, inhibition of liquid accumulation and mucus section into the lumen in response to short-acting beta-2 agonists that varies among asthmatic patients. MicroRNAs (miRNAs) are well-known post-translational regulators. Identifying miRNAs associated with BDR could lead to a better understanding of the underlying complex pathophysiology. Objective: The purpose of this study is to identify circulating miRNAs associated with bronchodilator response in asthma and decipher possible mechanism of bronchodilator response variation. Methods: We used available small RNA sequencing on blood serum from 1,134 asthmatic children aged 6 to 14 years who participated in the Genetics of Asthma in Costa Rica Study (GACRS). We filtered the participants into high and low bronchodilator response (BDR) quartiles and used DeSeq2 to identify miRNAs with differential expression (DE) in high (N= 277) vs low (N= 278) B...
Background: Asthma is a chronic heterogeneous respiratory disease involving differential pathophy... more Background: Asthma is a chronic heterogeneous respiratory disease involving differential pathophysiological pathways and consequently distinct asthma phenotypes. Objective and Methods: In the LEAD Study, a general population cohort (n=11.423) in Vienna ranging from 6-82 years of age, we addressed the prevalence of asthma and explored inflammatory asthma phenotypes that included allergic and non-allergic asthma, and within these phenotypes, an eosinophilic (eosinophils ≥300 cells/µL, or ≥150 cells/µL in the presence of ICS medication) or noneosinophilic (eosinophils <300 cells/µL, or <150 cells/µL in the presence of ICS) phenotype. In addition, we compared various factors related to biomarkers, body composition, lung function, and symptoms in control subjects versus subjects with current asthma (current doctor's diagnosis of asthma). Results: An overall prevalence of 4.6% was observed for current asthma. Furthermore, an age-dependent shift from allergic to nonallergic asthma was found. The non-eosinophilic phenotype was more prominent. Obesity was a prevalent condition, and body composition including visceral adipose tissue (VAT), is affected in current asthma versus controls. Conclusion: This broad-aged and large general population cohort identified differential patterns of inflammatory asthma phenotypes that were age-dependent. The presence of eosinophilia was associated with worse asthma control, increased asthma medication, increased VAT, and lower lung function, the opposite was found for the presence of an allergic asthma.
American Journal of Respiratory Cell and Molecular Biology
Obesity is a risk factor for the development of asthma and represents a difficult-to-treat diseas... more Obesity is a risk factor for the development of asthma and represents a difficult-to-treat disease phenotype. Aerobic glycolysis is emerging as a key feature of asthma, and changes in glucose metabolism are linked to leukocyte activation and adaptation to oxidative stress. Dysregulation of PKM2 (pyruvate kinase M2), the enzyme that catalyzes the last step of glycolysis, contributes to house dust mite (HDM)-induced airway inflammation and remodeling in lean mice. It remains unclear whether glycolytic reprogramming and dysregulation of PKM2 also contribute to obese asthma. The goal of the present study was to elucidate the functional role of PKM2 in a murine model of obese allergic asthma. We evaluated the small molecule activator of PKM2, TEPP46, and assessed the role of PKM2 using conditional ablation of the Pkm2 allele from airway epithelial cells. In obese C57BL/6NJ mice, parameters indicative of glycolytic reprogramming remained unchanged in the absence of stimulation with HDM. Obese mice that were subjected to HDM showed evidence of glycolytic reprogramming, and treatment with TEPP46 diminished airway inflammation, whereas parameters of airway remodeling were unaffected. Epithelial ablation of Pkm2 decreased central airway resistance in both lean and obese allergic mice in addition to decreasing inflammatory cytokines in the lung tissue. Lastly, we highlight a novel role for PKM2 in the regulation of glutathione-dependent protein oxidation in the lung tissue of obese allergic mice via a putative IFN-g-glutaredoxin1 pathway. Overall, targeting metabolism and protein oxidation may be a novel treatment strategy for obese allergic asthma.
Recently, “Technical standards for respiratory oscillometry” was published, which reviewed the ph... more Recently, “Technical standards for respiratory oscillometry” was published, which reviewed the physiological basis of oscillometric measures and detailed the technical factors related to equipment and test performance, quality assurance and reporting of results. Here we present a review of the clinical significance and applications of oscillometry. We briefly review the physiological principles of oscillometry and the basics of oscillometry interpretation, and then describe what is currently known about oscillometry in its role as a sensitive measure of airway resistance, bronchodilator responsiveness and bronchial challenge testing, and response to medical therapy, particularly in asthma and COPD. The technique may have unique advantages in situations where spirometry and other lung function tests are not suitable, such as in infants, neuromuscular disease, sleep apnoea and critical care. Other potential applications include detection of bronchiolitis obliterans, vocal cord dysfunc...
The measurement of lung volume is as old as the spirometer. Measurements of lung volume and its s... more The measurement of lung volume is as old as the spirometer. Measurements of lung volume and its subdivisions yield critical diagnostic information about the principle cause of disease, either restrictive with decreased volume or obstructive with increased volume. There are numerous simple and complex techniques for measuring lung volume including simple spirometry, body plethysmography, and the CT scan.
Background: Interleukin-1-dependent increases in glycolysis promote allergic airways disease in m... more Background: Interleukin-1-dependent increases in glycolysis promote allergic airways disease in mice and disruption of pyruvate kinase M2 (PKM2) activity is critical herein. Glutathione-S-transferase P (GSTP) has been implicated in asthma pathogenesis and regulates the oxidation state of proteins via S-glutathionylation. We addressed whether GSTP-dependent S-glutathionylation promotes allergic airways disease by promoting glycolytic reprogramming and whether it involves the disruption of PKM2. Methods: We used house dust mite (HDM) or interleukin-1β in C57BL6/NJ WT or mice that lack GSTP. Airway basal cells were stimulated with interleukin-1β and the selective GSTP inhibitor, TLK199. GSTP and PKM2 were evaluated in sputum samples of asthmatics and healthy controls and incorporated analysis of the U-BIOPRED severe asthma cohort database. Results: Ablation of Gstp decreased total S-glutathionylation and attenuated HDM-induced allergic airways disease and interleukin-1β-mediated inflammation. Gstp deletion or inhibition by TLK199 decreased the interleukin-1β-stimulated secretion of pro-inflammatory mediators and lactate by epithelial cells. 13 C-glucose metabolomics showed decreased glycolysis flux at the pyruvate kinase step in response to TLK199. GSTP and PKM2 levels were increased in BAL of HDM-exposed mice as well as in sputum of asthmatics compared to controls. Sputum proteomics and transcriptomics revealed strong correlations between GSTP, PKM2, and the glycolysis pathway in asthma. Conclusions: GSTP contributes to the pathogenesis of allergic airways disease in association with enhanced glycolysis and oxidative disruption of PKM2. Our findings also suggest a PKM2-GSTP-glycolysis signature in asthma that is associated with severe disease.
The Journal of Allergy and Clinical Immunology: In Practice, 2020
BACKGROUND: Biomarkers that can predict loss of asthma control among patients being considered fo... more BACKGROUND: Biomarkers that can predict loss of asthma control among patients being considered for step-down therapy in well-controlled disease are lacking. To evaluate whether baseline biomarkers of type 2 airway inflammation and/or serial measurement of fractional exhaled nitric oxide (FENO) predict loss of asthma control as therapy is stepped down. In subanalyses of a multicenter randomized, double-blind, parallel 3-arm trial comparing strategies for step-down therapy in well-controlled asthma (Long-Acting Beta-Agonist
Oscillometry (also known as the forced oscillation technique) measures the mechanical properties ... more Oscillometry (also known as the forced oscillation technique) measures the mechanical properties of the respiratory system (upper and intrathoracic airways, lung tissue and chest wall) during quiet tidal breathing, by the application of an oscillating pressure signal (input or forcing signal), most commonly at the mouth. With increased clinical and research use, it is critical that all technical details of the hardware design, signal processing and analyses, and testing protocols are transparent and clearly reported to allow standardisation, comparison and replication of clinical and research studies. Because of this need, an update of the 2003 European Respiratory Society (ERS) technical standards document was produced by an ERS task force of experts who are active in clinical oscillometry research.The aim of the task force was to provide technical recommendations regarding oscillometry measurement including hardware, software, testing protocols and quality control.The main changes...
Asthma is a chronic disorder characterized by inflammation, mucus metaplasia, airway remodeling, ... more Asthma is a chronic disorder characterized by inflammation, mucus metaplasia, airway remodeling, and hyperresponsiveness. We recently showed that IL-1–induced glycolytic reprogramming contributes to allergic airway disease using a murine house dust mite model. Moreover, levels of pyruvate kinase M2 (PKM2) were increased in this model as well as in nasal epithelial cells from asthmatics as compared with healthy controls. Although the tetramer form of PKM2 converts phosphoenolpyruvate to pyruvate, the dimeric form of PKM2 has alternative, nonglycolysis functions as a transcriptional coactivator to enhance the transcription of several proinflammatory cytokines. In the current study, we examined the impact of PKM2 on the pathogenesis of house dust mite–induced allergic airways disease in C57BL/6NJ mice. We report, in this study, that activation of PKM2, using the small molecule activator, TEPP46, augmented PKM activity in lung tissues and attenuated airway eosinophils, mucus metaplasia,...
Background and objective: The reduction of forced expiratory volume in 1 s (FEV 1 ) in response t... more Background and objective: The reduction of forced expiratory volume in 1 s (FEV 1 ) in response to methacholine challenge in asthma may reflect two components: airway narrowing, assessed by the change in FEV 1 /forced vital capacity (FVC), and airway closure, assessed by the change in FVC. The purpose of this study was to determine the degree and determinants of airway closure in response to methacholine in a large group of asthmatic patients participating in studies conducted by the American Lung Association-Airways Clinical Research Centers (ALA-ACRC). Methods: We used the methacholine challenge data from participants in five studies of the ALA-ACRC to determine the closing index, defined as the contribution of airway closure to the decrease in FEV 1 , and calculated as %ΔFVC/%ΔFEV 1 . Results: There were a total of 936 participants with asthma, among whom the median closing index was 0.67 relative to that of a published healthy population of 0.54. A higher closing index was associated with increased age (10-year increments) (0.04, 95% CI = 0.02, 0.05, P < 0.005) and obesity (0.07, 95% CI = 0.03, 0.10, P < 0.001). There was no association between the closing index and asthma control. Conclusion: Our findings confirm that airway closure in response to methacholine occurs in a large, diverse population of asthmatic participants, and that increased airway closure is associated with older age and obesity. These findings suggest that therapies targeting airway closure may be important in patients with a high closing index.
Platelet-activating factor (PAF) increases the bronchoconstrictor response of mammalian airways t... more Platelet-activating factor (PAF) increases the bronchoconstrictor response of mammalian airways to cholinergic agonists and is thus implicated as a potential mediator of airway hyperreactivity. This study further defines the nature of the increase in airway responsiveness induced by PAF. We employed an in situ canine tracheal preparation, which allows differentiation of the effects PAF has on airway smooth muscle contraction from confounding effects it has on inducing airway edema and secretions. We found that PAF, infused regionally into tracheal arteries, increases the responsiveness of the trachealis muscle to parasympathetic stimuli in a dose-dependent manner. This effect occurred within 15 min. To determine whether the increase in trachealis muscle responsiveness resulted from effects localized to the trachea, we compared the effect of PAF on the tracheal segment with effects of the lower airways of the lung. Delivered to the arteries perfusing the tracheal segment, PAF did not...
American Journal of Physiology-Lung Cellular and Molecular Physiology, 2001
Different strains of mice exhibit different degrees of airway hyperresponsiveness after sensitiza... more Different strains of mice exhibit different degrees of airway hyperresponsiveness after sensitization to and airway challenge with ovalbumin. Antibody responses in BALB/c mice far exceeded those in C57BL/6 mice; in contrast, although responsiveness to methacholine was much higher in the BALB/c mice, the number of eosinophils in the bronchoalveolar lavage fluid was higher in C57BL/6 animals. Sensitized and challenged BALB/c mice developed increases in lung resistance and decreases in dynamic compliance after methacholine or 5-hydroxytryptamine inhalation. C57BL/6 mice only exhibited significant levels of responsiveness when dynamic compliance was monitored in response to inhaled 5-hydroxytryptamine. Eosinophils accumulated in the peribronchial and peripheral lung tissue in BALB/c mice but were distributed diffusely in the peripheral lung tissue of C57BL/6 mice. Thus, in addition to differences in antibody responses and cholinergic agonist reactivity, differences in the responses of l...
The Journal of continuing education in the health professions
In an era of competing priorities, funding is increasingly restricted for offices of faculty affa... more In an era of competing priorities, funding is increasingly restricted for offices of faculty affairs and development. Opportunities for professional staff to grow and network through attendance at national meetings and to share best practices are limited. We sought to describe a community of practice established to enhance the professional development of faculty affairs professionals and to document its impact. We outlined the process of formation of the New England Network for Faculty Affairs (NENFA), reviewed the pedagogical approaches to professional development, and surveyed members to evaluate the impact of NENFA on their activities, professional network and their institutions. After a successful 2011 initial meeting, NENFA created an organizing committee and conducted a needs assessment among potential members. NENFA's charter, mission, goals, and structure were based on survey results. NENFA's regional community of practice grew to 31 institutions and held 10 meetings...
Heterogeneous therapeutic responses to leukotriene modifiers (LTMs) are likely due to variation i... more Heterogeneous therapeutic responses to leukotriene modifiers (LTMs) are likely due to variation in patient genetics. Although prior candidate gene studies implicated multiple pharmacogenetic loci, to date, no genome-wide association study (GWAS) of LTM response was reported. In this study, DNA and phenotypic information from two placebo-controlled trials (total N=526) of zileuton response were interrogated. Using a gene-environment (G × E) GWAS model, we evaluated 12-week change in forced expiratory volume in 1 second (ΔFEV1) following LTM treatment. The top 50 single-nucleotide polymorphism associations were replicated in an independent zileuton treatment cohort, and two additional cohorts of montelukast response. In a combined analysis (discovery+replication), rs12436663 in MRPP3 achieved genome-wide significance (P=6.28 × 10(-08)); homozygous rs12436663 carriers showed a significant reduction in mean ΔFEV1 following zileuton treatment. In addition, rs517020 in GLT1D1 was associat...
Asthma is a common chronic respiratory disease characterized by airway hyperresponsiveness (AHR).... more Asthma is a common chronic respiratory disease characterized by airway hyperresponsiveness (AHR). The genetics of asthma have been widely studied in mouse and human, and homologous genomic regions have been associated with mouse AHR and human asthma-related phenotypes. Our goal was to identify asthma-related genes by integrating AHR associations in mouse with human genome-wide association study (GWAS) data. We used Efficient Mixed Model Association (EMMA) analysis to conduct a GWAS of baseline AHR measures from males and females of 31 mouse strains. Genes near or containing SNPs with EMMA p-values ,0.001 were selected for further study in human GWAS. The results of the previously reported EVE consortium asthma GWAS meta-analysis consisting of 12,958 diverse North American subjects from 9 study centers were used to select a subset of homologous genes with evidence of association with asthma in humans. Following validation attempts in three human asthma GWAS (i.e., Sepracor/LOCCS/LODO/Illumina, GABRIEL, DAG) and two human AHR GWAS (i.e., SHARP, DAG), the Kv channel interacting protein 4 (KCNIP4) gene was identified as nominally associated with both asthma and AHR at a gene-and SNP-level. In EVE, the smallest KCNIP4 association was at rs6833065 (P-value 2.9e-04), while the strongest associations for Sepracor/LOCCS/LODO/Illumina, GABRIEL, DAG were 1.5e-03, 1.0e-03, 3.1e-03 at rs7664617, rs4697177, rs4696975, respectively. At a SNP level, the strongest association across all asthma GWAS was at rs4697177 (P-value 1.1e-04). The smallest P-values for association with AHR were 2.3e-03 at rs11947661 in SHARP and 2.1e-03 at rs402802 in DAG. Functional studies are required to validate the potential involvement of KCNIP4 in modulating asthma susceptibility and/or AHR. Our results suggest that a useful approach to identify genes associated with human asthma is to leverage mouse AHR association data.
The Childhood Asthma Management Program (CAMP), a multicenter clinical trial sponsored by the Div... more The Childhood Asthma Management Program (CAMP), a multicenter clinical trial sponsored by the Division of Lung Diseases of the National Heart, Lung, and Blood Institute (NHLBI), is the largest outcome study of mild to moderate asthma in children to be undertaken, with eight clinical centers in the United States and Canada participating. The initial recruitment goal was 960 children within an 18-month recruitment period. Recruitment was extended to 23 months, with 1041 children randomized from late December, 1993, to early September, 1995. In this time interval each of the eight centers met the recruitment goal of 120 using a variety of self-selected recruitment strategies. The goal for minority recruiting was 33%, or 320 of the planned 960 children to be recruited. CAMP achieved the overall goal for the number of minorities, with 330 patients. Three centers recruited at or above the expected rate from the beginning. The other five centers had significant delays in recruitment. Examination of the recruitment experiences of the centers with and without delays did not indicate any single recruitment strategy that was certain to be successful. The most commonly cited factors for success were a cohesive staff, endorsement of participation by the child's primary care provider, and ability of the staff to be flexible and honest in assessing progress and the value of recruiting methods being used.
Flavored e-cigarettes are preferred by the majority of users yet their potential toxicity is unkn... more Flavored e-cigarettes are preferred by the majority of users yet their potential toxicity is unknown. Therefore our aim was to determine the effect of selected flavored e-cigarettes, with or without nicotine, on allergic airways disease in mice. Balb/c mice were challenged with PBS or house dust mite (HDM) (Days 0, 7, 14-18) and exposed to room air or e-cigarette aerosol for 30 min twice daily, 6 days/week from Days 0-18 (n = 8-12/group). Mice were exposed to Room Air, vehicle control (50%VG/%50PG), Black Licorice, Kola, Banana Pudding or Cinnacide without or with 12 mg/mL nicotine. Mice were assessed at 72 hours after the final HDM challenge. Compared to mice challenged with HDM and exposed to Room Air, nicotine-free Cinnacide reduced airway inflammation (p = 0.045) and increased peripheral airway hyperresponsiveness (p = 0.02), nicotine-free Banana Pudding increased soluble lung collagen (p = 0.049), with a trend towards increased airway inflammation with nicotine-free Black Licorice exposure (p = 0.089). In contrast, all e-cigarettes containing nicotine suppressed airway inflammation (p < 0.001 for all) but did not alter airway hyperresponsiveness or airway remodeling. Flavored e-cigarettes without nicotine had significant but heterogeneous effects on features of allergic airways disease. This suggests that some flavored e-cigarettes may alter asthma pathophysiology even when used without nicotine. Electronic cigarette (e-cigarette) use has dramatically increased in recent years due to its portrayal as a healthier alternative to tobacco cigarettes. E-cigarette use amongst high school aged children in the US jumped from 1.5% in 2011 to over 15% in 2015 1 . Similarly, almost 9% of 18-24 year olds are current e-cigarette users 2 . E-cigarettes administer nicotine as an aerosol, do not require tobacco combustion and therefore are assumed to remove the risks associated with tobacco cigarettes. However, e-cigarettes contain numerous toxic compounds long associated with adverse respiratory outcomes 3 . The humectant propylene glycol leads to respiratory symptoms when inhaled 4 , while nicotine adversely effects respiratory health 5 . E-cigarette liquids are also available in a seemingly limitless combination of flavor additives, with almost all users under 30 and almost 70% of older adults using flavored e-cigarettes 6 . Additionally, up to 66% of US high school aged children use e-cigarettes with only flavoring/s i.e. no nicotine 7 . However, e-cigarette flavorings have been shown to have toxic effects on human airway epithelial and immune cells . Despite the high use of flavored e-cigarettes and the potential toxicity, little is known as to the adverse effects of flavored e-cigarettes on lung function and respiratory health. Asthmatics are particularly susceptible to the effects of toxic, inhaled substances such as tobacco, with tobacco smoking asthmatics reporting worse asthma control, more unscheduled health care visits, and a greater requirement for oral corticosteroids 12 . This increased disease severity is due to both worse lung function 13 and greater severity of airway hyperresponsiveness 14 . There is currently little evidence as to the effect of e-cigarette use in patients with asthma. One study reported that asthmatic patients who transitioned from tobacco cigarette smoking to e-cigarette use reported improved asthma symptoms and lung function 15 . However, this does not address whether e-cigarettes themselves may be detrimental to asthmatics. In healthy volunteers, acute e-cigarette use can reduce lung function . Importantly, the reduction in lung function was exaggerated in patients with asthma 18 , suggesting that asthmatics may be more susceptible to the effects of e-cigarettes. However, it is unknown whether these acute effects of e-cigarettes on lung function reflect the potential effects on asthma pathophysiology.
Genome-wide association study (GWAS) is a powerful tool to identify novel pharmacogenetic single ... more Genome-wide association study (GWAS) is a powerful tool to identify novel pharmacogenetic single nucleotide polymorphisms (SNPs). Leukotriene receptor antagonists (LTRAs) are a major class of asthma medications, and genetic factors contribute to variable responses to these drugs. We used GWAS to identify novel SNPs associated with the response to the LTRA, montelukast, in asthmatics. Using genome-wide genotype and phenotypic data available from American Lung Association -Asthma Clinical Research Center (ALA-ACRC) cohorts, we evaluated 8-week change in FEV 1 related to montelukast administration in a discovery population of 133 asthmatics. The top 200 SNPs from the discovery GWAS were then tested in 184 additional samples from two independent cohorts. Twenty-eight SNP associations from the discovery GWAS were replicated. Of these, rs6475448 achieved genome-wide significance (combined P = 1.97 x 10 -09 ), and subjects from all four studies who were homozygous for rs6475448 showed increased ΔFEV 1 from baseline in response to montelukast.
Background-Asthma is a common chronic respiratory disease in children and adults. An important ge... more Background-Asthma is a common chronic respiratory disease in children and adults. An important genetic component to asthma susceptibility has long been recognized, most recently through the identification of several genes (e.g., ORMDL3, PDE4D, HLA-DQ, and TLE4) via genome-wide association studies. Objective-To identify genetic variants associated with asthma affection status using genomewide association data. Methods-We describe results from a genome-wide association study on asthma performed in 3855 subjects using a panel of 455 089 single nucleotide polymorphisms (SNPs). Result-The genome-wide association study resulted in the prioritization of 33 variants for immediate follow-up in a multi-staged replication effort. Of these, a common polymorphism (rs9272346) localizing to within 1 Kb of HLA-DQA1 (chromosome 6p21.3) was associated with asthma in adults (P-value = 2.2E-08) with consistent evidence in the more heterogeneous group of adults and children (P-value = 1.0E-04). Moreover, some genes identified in prior asthma GWAS were nominally associated with asthma in our populations. Conclusion-Overall, our findings further replicate the HLA-DQ region in the pathogenesis of asthma. HLA-DQA1 is the fourth member of the HLA family found to be associated with asthma, in addition to the previously identified HLA-DRA, HLA-DQB1 and HLA-DQA2.
Rationale: Bronchodilator response (BDR) is a measure of improvement in airway smooth muscle tone... more Rationale: Bronchodilator response (BDR) is a measure of improvement in airway smooth muscle tone, inhibition of liquid accumulation and mucus section into the lumen in response to short-acting beta-2 agonists that varies among asthmatic patients. MicroRNAs (miRNAs) are well-known post-translational regulators. Identifying miRNAs associated with BDR could lead to a better understanding of the underlying complex pathophysiology. Objective: The purpose of this study is to identify circulating miRNAs associated with bronchodilator response in asthma and decipher possible mechanism of bronchodilator response variation. Methods: We used available small RNA sequencing on blood serum from 1,134 asthmatic children aged 6 to 14 years who participated in the Genetics of Asthma in Costa Rica Study (GACRS). We filtered the participants into high and low bronchodilator response (BDR) quartiles and used DeSeq2 to identify miRNAs with differential expression (DE) in high (N= 277) vs low (N= 278) B...
Background: Asthma is a chronic heterogeneous respiratory disease involving differential pathophy... more Background: Asthma is a chronic heterogeneous respiratory disease involving differential pathophysiological pathways and consequently distinct asthma phenotypes. Objective and Methods: In the LEAD Study, a general population cohort (n=11.423) in Vienna ranging from 6-82 years of age, we addressed the prevalence of asthma and explored inflammatory asthma phenotypes that included allergic and non-allergic asthma, and within these phenotypes, an eosinophilic (eosinophils ≥300 cells/µL, or ≥150 cells/µL in the presence of ICS medication) or noneosinophilic (eosinophils <300 cells/µL, or <150 cells/µL in the presence of ICS) phenotype. In addition, we compared various factors related to biomarkers, body composition, lung function, and symptoms in control subjects versus subjects with current asthma (current doctor's diagnosis of asthma). Results: An overall prevalence of 4.6% was observed for current asthma. Furthermore, an age-dependent shift from allergic to nonallergic asthma was found. The non-eosinophilic phenotype was more prominent. Obesity was a prevalent condition, and body composition including visceral adipose tissue (VAT), is affected in current asthma versus controls. Conclusion: This broad-aged and large general population cohort identified differential patterns of inflammatory asthma phenotypes that were age-dependent. The presence of eosinophilia was associated with worse asthma control, increased asthma medication, increased VAT, and lower lung function, the opposite was found for the presence of an allergic asthma.
American Journal of Respiratory Cell and Molecular Biology
Obesity is a risk factor for the development of asthma and represents a difficult-to-treat diseas... more Obesity is a risk factor for the development of asthma and represents a difficult-to-treat disease phenotype. Aerobic glycolysis is emerging as a key feature of asthma, and changes in glucose metabolism are linked to leukocyte activation and adaptation to oxidative stress. Dysregulation of PKM2 (pyruvate kinase M2), the enzyme that catalyzes the last step of glycolysis, contributes to house dust mite (HDM)-induced airway inflammation and remodeling in lean mice. It remains unclear whether glycolytic reprogramming and dysregulation of PKM2 also contribute to obese asthma. The goal of the present study was to elucidate the functional role of PKM2 in a murine model of obese allergic asthma. We evaluated the small molecule activator of PKM2, TEPP46, and assessed the role of PKM2 using conditional ablation of the Pkm2 allele from airway epithelial cells. In obese C57BL/6NJ mice, parameters indicative of glycolytic reprogramming remained unchanged in the absence of stimulation with HDM. Obese mice that were subjected to HDM showed evidence of glycolytic reprogramming, and treatment with TEPP46 diminished airway inflammation, whereas parameters of airway remodeling were unaffected. Epithelial ablation of Pkm2 decreased central airway resistance in both lean and obese allergic mice in addition to decreasing inflammatory cytokines in the lung tissue. Lastly, we highlight a novel role for PKM2 in the regulation of glutathione-dependent protein oxidation in the lung tissue of obese allergic mice via a putative IFN-g-glutaredoxin1 pathway. Overall, targeting metabolism and protein oxidation may be a novel treatment strategy for obese allergic asthma.
Recently, “Technical standards for respiratory oscillometry” was published, which reviewed the ph... more Recently, “Technical standards for respiratory oscillometry” was published, which reviewed the physiological basis of oscillometric measures and detailed the technical factors related to equipment and test performance, quality assurance and reporting of results. Here we present a review of the clinical significance and applications of oscillometry. We briefly review the physiological principles of oscillometry and the basics of oscillometry interpretation, and then describe what is currently known about oscillometry in its role as a sensitive measure of airway resistance, bronchodilator responsiveness and bronchial challenge testing, and response to medical therapy, particularly in asthma and COPD. The technique may have unique advantages in situations where spirometry and other lung function tests are not suitable, such as in infants, neuromuscular disease, sleep apnoea and critical care. Other potential applications include detection of bronchiolitis obliterans, vocal cord dysfunc...
The measurement of lung volume is as old as the spirometer. Measurements of lung volume and its s... more The measurement of lung volume is as old as the spirometer. Measurements of lung volume and its subdivisions yield critical diagnostic information about the principle cause of disease, either restrictive with decreased volume or obstructive with increased volume. There are numerous simple and complex techniques for measuring lung volume including simple spirometry, body plethysmography, and the CT scan.
Background: Interleukin-1-dependent increases in glycolysis promote allergic airways disease in m... more Background: Interleukin-1-dependent increases in glycolysis promote allergic airways disease in mice and disruption of pyruvate kinase M2 (PKM2) activity is critical herein. Glutathione-S-transferase P (GSTP) has been implicated in asthma pathogenesis and regulates the oxidation state of proteins via S-glutathionylation. We addressed whether GSTP-dependent S-glutathionylation promotes allergic airways disease by promoting glycolytic reprogramming and whether it involves the disruption of PKM2. Methods: We used house dust mite (HDM) or interleukin-1β in C57BL6/NJ WT or mice that lack GSTP. Airway basal cells were stimulated with interleukin-1β and the selective GSTP inhibitor, TLK199. GSTP and PKM2 were evaluated in sputum samples of asthmatics and healthy controls and incorporated analysis of the U-BIOPRED severe asthma cohort database. Results: Ablation of Gstp decreased total S-glutathionylation and attenuated HDM-induced allergic airways disease and interleukin-1β-mediated inflammation. Gstp deletion or inhibition by TLK199 decreased the interleukin-1β-stimulated secretion of pro-inflammatory mediators and lactate by epithelial cells. 13 C-glucose metabolomics showed decreased glycolysis flux at the pyruvate kinase step in response to TLK199. GSTP and PKM2 levels were increased in BAL of HDM-exposed mice as well as in sputum of asthmatics compared to controls. Sputum proteomics and transcriptomics revealed strong correlations between GSTP, PKM2, and the glycolysis pathway in asthma. Conclusions: GSTP contributes to the pathogenesis of allergic airways disease in association with enhanced glycolysis and oxidative disruption of PKM2. Our findings also suggest a PKM2-GSTP-glycolysis signature in asthma that is associated with severe disease.
The Journal of Allergy and Clinical Immunology: In Practice, 2020
BACKGROUND: Biomarkers that can predict loss of asthma control among patients being considered fo... more BACKGROUND: Biomarkers that can predict loss of asthma control among patients being considered for step-down therapy in well-controlled disease are lacking. To evaluate whether baseline biomarkers of type 2 airway inflammation and/or serial measurement of fractional exhaled nitric oxide (FENO) predict loss of asthma control as therapy is stepped down. In subanalyses of a multicenter randomized, double-blind, parallel 3-arm trial comparing strategies for step-down therapy in well-controlled asthma (Long-Acting Beta-Agonist
Oscillometry (also known as the forced oscillation technique) measures the mechanical properties ... more Oscillometry (also known as the forced oscillation technique) measures the mechanical properties of the respiratory system (upper and intrathoracic airways, lung tissue and chest wall) during quiet tidal breathing, by the application of an oscillating pressure signal (input or forcing signal), most commonly at the mouth. With increased clinical and research use, it is critical that all technical details of the hardware design, signal processing and analyses, and testing protocols are transparent and clearly reported to allow standardisation, comparison and replication of clinical and research studies. Because of this need, an update of the 2003 European Respiratory Society (ERS) technical standards document was produced by an ERS task force of experts who are active in clinical oscillometry research.The aim of the task force was to provide technical recommendations regarding oscillometry measurement including hardware, software, testing protocols and quality control.The main changes...
Asthma is a chronic disorder characterized by inflammation, mucus metaplasia, airway remodeling, ... more Asthma is a chronic disorder characterized by inflammation, mucus metaplasia, airway remodeling, and hyperresponsiveness. We recently showed that IL-1–induced glycolytic reprogramming contributes to allergic airway disease using a murine house dust mite model. Moreover, levels of pyruvate kinase M2 (PKM2) were increased in this model as well as in nasal epithelial cells from asthmatics as compared with healthy controls. Although the tetramer form of PKM2 converts phosphoenolpyruvate to pyruvate, the dimeric form of PKM2 has alternative, nonglycolysis functions as a transcriptional coactivator to enhance the transcription of several proinflammatory cytokines. In the current study, we examined the impact of PKM2 on the pathogenesis of house dust mite–induced allergic airways disease in C57BL/6NJ mice. We report, in this study, that activation of PKM2, using the small molecule activator, TEPP46, augmented PKM activity in lung tissues and attenuated airway eosinophils, mucus metaplasia,...
Background and objective: The reduction of forced expiratory volume in 1 s (FEV 1 ) in response t... more Background and objective: The reduction of forced expiratory volume in 1 s (FEV 1 ) in response to methacholine challenge in asthma may reflect two components: airway narrowing, assessed by the change in FEV 1 /forced vital capacity (FVC), and airway closure, assessed by the change in FVC. The purpose of this study was to determine the degree and determinants of airway closure in response to methacholine in a large group of asthmatic patients participating in studies conducted by the American Lung Association-Airways Clinical Research Centers (ALA-ACRC). Methods: We used the methacholine challenge data from participants in five studies of the ALA-ACRC to determine the closing index, defined as the contribution of airway closure to the decrease in FEV 1 , and calculated as %ΔFVC/%ΔFEV 1 . Results: There were a total of 936 participants with asthma, among whom the median closing index was 0.67 relative to that of a published healthy population of 0.54. A higher closing index was associated with increased age (10-year increments) (0.04, 95% CI = 0.02, 0.05, P < 0.005) and obesity (0.07, 95% CI = 0.03, 0.10, P < 0.001). There was no association between the closing index and asthma control. Conclusion: Our findings confirm that airway closure in response to methacholine occurs in a large, diverse population of asthmatic participants, and that increased airway closure is associated with older age and obesity. These findings suggest that therapies targeting airway closure may be important in patients with a high closing index.
Platelet-activating factor (PAF) increases the bronchoconstrictor response of mammalian airways t... more Platelet-activating factor (PAF) increases the bronchoconstrictor response of mammalian airways to cholinergic agonists and is thus implicated as a potential mediator of airway hyperreactivity. This study further defines the nature of the increase in airway responsiveness induced by PAF. We employed an in situ canine tracheal preparation, which allows differentiation of the effects PAF has on airway smooth muscle contraction from confounding effects it has on inducing airway edema and secretions. We found that PAF, infused regionally into tracheal arteries, increases the responsiveness of the trachealis muscle to parasympathetic stimuli in a dose-dependent manner. This effect occurred within 15 min. To determine whether the increase in trachealis muscle responsiveness resulted from effects localized to the trachea, we compared the effect of PAF on the tracheal segment with effects of the lower airways of the lung. Delivered to the arteries perfusing the tracheal segment, PAF did not...
American Journal of Physiology-Lung Cellular and Molecular Physiology, 2001
Different strains of mice exhibit different degrees of airway hyperresponsiveness after sensitiza... more Different strains of mice exhibit different degrees of airway hyperresponsiveness after sensitization to and airway challenge with ovalbumin. Antibody responses in BALB/c mice far exceeded those in C57BL/6 mice; in contrast, although responsiveness to methacholine was much higher in the BALB/c mice, the number of eosinophils in the bronchoalveolar lavage fluid was higher in C57BL/6 animals. Sensitized and challenged BALB/c mice developed increases in lung resistance and decreases in dynamic compliance after methacholine or 5-hydroxytryptamine inhalation. C57BL/6 mice only exhibited significant levels of responsiveness when dynamic compliance was monitored in response to inhaled 5-hydroxytryptamine. Eosinophils accumulated in the peribronchial and peripheral lung tissue in BALB/c mice but were distributed diffusely in the peripheral lung tissue of C57BL/6 mice. Thus, in addition to differences in antibody responses and cholinergic agonist reactivity, differences in the responses of l...
The Journal of continuing education in the health professions
In an era of competing priorities, funding is increasingly restricted for offices of faculty affa... more In an era of competing priorities, funding is increasingly restricted for offices of faculty affairs and development. Opportunities for professional staff to grow and network through attendance at national meetings and to share best practices are limited. We sought to describe a community of practice established to enhance the professional development of faculty affairs professionals and to document its impact. We outlined the process of formation of the New England Network for Faculty Affairs (NENFA), reviewed the pedagogical approaches to professional development, and surveyed members to evaluate the impact of NENFA on their activities, professional network and their institutions. After a successful 2011 initial meeting, NENFA created an organizing committee and conducted a needs assessment among potential members. NENFA's charter, mission, goals, and structure were based on survey results. NENFA's regional community of practice grew to 31 institutions and held 10 meetings...
Heterogeneous therapeutic responses to leukotriene modifiers (LTMs) are likely due to variation i... more Heterogeneous therapeutic responses to leukotriene modifiers (LTMs) are likely due to variation in patient genetics. Although prior candidate gene studies implicated multiple pharmacogenetic loci, to date, no genome-wide association study (GWAS) of LTM response was reported. In this study, DNA and phenotypic information from two placebo-controlled trials (total N=526) of zileuton response were interrogated. Using a gene-environment (G × E) GWAS model, we evaluated 12-week change in forced expiratory volume in 1 second (ΔFEV1) following LTM treatment. The top 50 single-nucleotide polymorphism associations were replicated in an independent zileuton treatment cohort, and two additional cohorts of montelukast response. In a combined analysis (discovery+replication), rs12436663 in MRPP3 achieved genome-wide significance (P=6.28 × 10(-08)); homozygous rs12436663 carriers showed a significant reduction in mean ΔFEV1 following zileuton treatment. In addition, rs517020 in GLT1D1 was associat...
Asthma is a common chronic respiratory disease characterized by airway hyperresponsiveness (AHR).... more Asthma is a common chronic respiratory disease characterized by airway hyperresponsiveness (AHR). The genetics of asthma have been widely studied in mouse and human, and homologous genomic regions have been associated with mouse AHR and human asthma-related phenotypes. Our goal was to identify asthma-related genes by integrating AHR associations in mouse with human genome-wide association study (GWAS) data. We used Efficient Mixed Model Association (EMMA) analysis to conduct a GWAS of baseline AHR measures from males and females of 31 mouse strains. Genes near or containing SNPs with EMMA p-values ,0.001 were selected for further study in human GWAS. The results of the previously reported EVE consortium asthma GWAS meta-analysis consisting of 12,958 diverse North American subjects from 9 study centers were used to select a subset of homologous genes with evidence of association with asthma in humans. Following validation attempts in three human asthma GWAS (i.e., Sepracor/LOCCS/LODO/Illumina, GABRIEL, DAG) and two human AHR GWAS (i.e., SHARP, DAG), the Kv channel interacting protein 4 (KCNIP4) gene was identified as nominally associated with both asthma and AHR at a gene-and SNP-level. In EVE, the smallest KCNIP4 association was at rs6833065 (P-value 2.9e-04), while the strongest associations for Sepracor/LOCCS/LODO/Illumina, GABRIEL, DAG were 1.5e-03, 1.0e-03, 3.1e-03 at rs7664617, rs4697177, rs4696975, respectively. At a SNP level, the strongest association across all asthma GWAS was at rs4697177 (P-value 1.1e-04). The smallest P-values for association with AHR were 2.3e-03 at rs11947661 in SHARP and 2.1e-03 at rs402802 in DAG. Functional studies are required to validate the potential involvement of KCNIP4 in modulating asthma susceptibility and/or AHR. Our results suggest that a useful approach to identify genes associated with human asthma is to leverage mouse AHR association data.
The Childhood Asthma Management Program (CAMP), a multicenter clinical trial sponsored by the Div... more The Childhood Asthma Management Program (CAMP), a multicenter clinical trial sponsored by the Division of Lung Diseases of the National Heart, Lung, and Blood Institute (NHLBI), is the largest outcome study of mild to moderate asthma in children to be undertaken, with eight clinical centers in the United States and Canada participating. The initial recruitment goal was 960 children within an 18-month recruitment period. Recruitment was extended to 23 months, with 1041 children randomized from late December, 1993, to early September, 1995. In this time interval each of the eight centers met the recruitment goal of 120 using a variety of self-selected recruitment strategies. The goal for minority recruiting was 33%, or 320 of the planned 960 children to be recruited. CAMP achieved the overall goal for the number of minorities, with 330 patients. Three centers recruited at or above the expected rate from the beginning. The other five centers had significant delays in recruitment. Examination of the recruitment experiences of the centers with and without delays did not indicate any single recruitment strategy that was certain to be successful. The most commonly cited factors for success were a cohesive staff, endorsement of participation by the child's primary care provider, and ability of the staff to be flexible and honest in assessing progress and the value of recruiting methods being used.
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Papers by Charles Irvin