Project description:Airflow limitation in COPD patients is not fully reversible. However, there may be large variability in bronchodilator responsiveness (BDR) among COPD patients, and familial aggregation of BDR suggests a genetic component. Therefore, we investigated the association between six candidate genes and BDR in subjects with severe COPD. A total of 389 subjects from the National Emphysema Treatment Trial (NETT) were analyzed. Bronchodilator responsiveness to albuterol was expressed in three ways: absolute change in FEV(1), change in FEV(1) as a percent of baseline FEV(1), and change in FEV(1) as a percent of predicted FEV(1). Genotyping was completed for 122 single nucleotide polymorphisms (SNPs) in six candidate genes (EPHX1, SFTPB, TGFB1, SERPINE2, GSTP1, ADRB2). Associations between BDR phenotypes and SNP genotypes were tested using linear regression, adjusting for age, sex, pack-years of smoking, and height. Genes associated with BDR phenotypes in the NETT subjects were assessed for replication in 127 pedigrees from the Boston Early-Onset COPD (EOCOPD) Study. Three SNPs in EPHX1 (p=0.009-0.04), three SNPs in SERPINE2 (p=0.004-0.05) and two SNPs in ADRB2 (0.04-0.05) were significantly associated with BDR phenotypes in NETT subjects. One SNP in EPHX1 (rs1009668, p=0.04) was significantly replicated in EOCOPD subjects. SNPs in SFTPB, TGFB1, and GSTP1 genes were not associated with BDR. In conclusion, a polymorphism of EPHX1 was associated with bronchodilator responsiveness phenotypes in subjects with severe COPD.
Project description:BackgroundBronchodilator responsiveness (BDR) in obstructive lung disease varies over time and may be associated with distinct clinical features.Research questionIs consistent BDR over time (always present) differentially associated with obstructive lung disease features relative to inconsistent (sometimes present) or never (never present) BDR in tobacco-exposed people with or without COPD?Study design and methodsWe retrospectively analyzed data from 2,269 tobacco-exposed participants in the Subpopulations and Intermediate Outcome Measures in COPD Study with or without COPD. We used various BDR definitions: change of ≥ 200 mL and ≥ 12% in FEV1 (FEV1-BDR), change in FVC (FVC-BDR), and change in in FEV1, FVC or both (ATS-BDR). Using generalized linear models adjusted for demographics, smoking history, FEV1 % predicted after bronchodilator administration, and number of visits that the participant completed, we assessed the association of BDR group: (1) consistent BDR, (2) inconsistent BDR, and (3) never BDR with asthma, CT scan features, blood eosinophil levels, and FEV1 decline in participants without COPD (Global Initiative for Chronic Obstructive Lung Disease [GOLD] stage 0) and the entire cohort (participants with or without COPD).ResultsBoth consistent and inconsistent ATS-BDR were associated with asthma history and greater small airways disease (%parametric response mapping functional small airways disease) relative to never ATS-BDR in participants with GOLD stage 0 disease and the entire cohort. We observed similar findings using FEV1-BDR and FVC-BDR definitions. Eosinophils did not vary consistently among BDR groups. Consistent BDR was associated with FEV1 decline over time relative to never BDR in the entire cohort. In participants with GOLD stage 0 disease, both the inconsistent ATS-BDR group (OR, 3.20; 95% CI, 2.21-4.66; P < .001) and consistent ATS-BDR group (OR, 9.48; 95% CI, 3.77-29.12; P < .001) were associated with progression to COPD relative to the never ATS-BDR group.InterpretationDemonstration of BDR, even once, describes an obstructive lung disease phenotype with a history of asthma and greater small airways disease. Consistent demonstration of BDR indicated a high risk of lung function decline over time in the entire cohort and was associated with higher risk of progression to COPD in patients with GOLD stage 0 disease.
Project description:BackgroundThe relationship between patient-reported symptoms and objective measures of lung function is poorly understood.AimTo determine the association between responsiveness to bronchodilator and respiratory symptoms in random population samples.Methods4669 people aged 40 years and older from 8 sites in Canada completed interviewer-administered respiratory questionnaires and performed spirometry before and after administration of 200 ug of inhaled salbutamol. The effect of anthropometric variables, smoking exposure and doctor-diagnosed asthma (DDA) on bronchodilator responsiveness in forced expiratory volume in 1 second (FEV1) and in forced vital capacity (FVC) were evaluated. Multiple logistic regression was used to test for association between quintiles of increasing changes in FEV1 and in FVC after bronchodilator and several respiratory symptoms.ResultsDeterminants of bronchodilator change in FEV1 and FVC included age, DDA, smoking, respiratory drug use and female gender [p<0.005 to p<0.0001 ]. In subjects without doctor-diagnosed asthma or COPD, bronchodilator response in FEV1 was associated with wheezing [p for trend<0.0001], while bronchodilator response for FVC was associated with breathlessness. [p for trend <0.0001].ConclusionsBronchodilator responsiveness in FEV1 or FVC are associated with different respiratory symptoms in the community. Both flow and volume bronchodilator responses are useful parameters which together can be predictive of both wheezing and breathlessness in the general population.
Project description:BackgroundBronchodilator responsiveness testing is mainly used for diagnosing asthma. We aimed to investigate whether it is associated with progression to chronic airflow obstruction over time.MethodsThe multinational Burden of Obstructive Lung Disease cohort study surveyed adults, aged 40 years and above, at baseline and followed them up after a mean of 9.1 years. Recruitment took place between January 2, 2003 and December 26, 2016. Follow-up measurements were collected between January 29, 2019 and October 24, 2021. On both occasions, study participants provided information on respiratory symptoms, health status and several environmental and lifestyle exposures. They also underwent pre- and post-bronchodilator spirometry. We defined bronchodilator responsiveness at baseline using the American Thoracic Society and European Respiratory Society (ATS/ERS) 2022 definition, and the presence of chronic airflow obstruction at follow-up as a post-bronchodilator forced expiratory volume in 1 s to forced vital capacity ratio (FEV1/FVC) less than the lower limit of normal. We used multi-level regression models to estimate the association between baseline bronchodilator responsiveness and incident chronic airflow obstruction. We stratified analyses by gender and performed a sensitivity analysis in never smokers.FindingsWe analysed data from 3701 adults with 56% being women. Compared to those without bronchodilator responsiveness at baseline, those with bronchodilator responsiveness had 36% increased risk of developing chronic airflow obstruction (RR: 1.36, 95%CI 1.04, 1.80). This effect was stronger in women (RR: 1.45, 95%CI 1.09, 1.91) than men (RR: 1.07, 95%CI 0.51, 2.24). Never smokers with bronchodilator responsiveness also were at greater risk of incident chronic airflow obstruction (RR: 1.48, 95%CI 1.01, 2.20).InterpretationBronchodilator responsiveness appears to be a risk factor for incident chronic airflow obstruction. It is important that future studies in other large population-based cohorts replicate these findings.FundingNational Heart and Lung Institute, UK Medical Research Council, and Wellcome Trust.
Project description:Short-acting inhaled beta2-agonists such as albuterol are used for bronchodilation and are the mainstay of asthma treatment worldwide. There is significant variation in bronchodilator responsiveness to albuterol not only between individuals but also across racial/ethnic groups. The beta2-adrenergic receptor (beta2AR) is the target for beta2-agonist drugs. The enzyme, S-nitrosoglutathione reductase (GSNOR), which regulates levels of the endogenous bronchodilator S-nitrosoglutathione, has been shown to modulate the response to beta2-agonists.We hypothesized that there are pharmacogenetic interactions between GSNOR and beta2AR gene variants that are associated with variable response to albuterol.We performed family-based analyses to test for association between GSNOR gene variants and asthma and related phenotypes in 609 Puerto Rican and Mexican families with asthma. In addition, we tested these individuals for pharmacogenetic interaction between GSNOR and beta2AR gene variants and responsiveness to albuterol using linear regression. Cell transfection experiments were performed to test the potential effect of the GSNOR gene variants.Among Puerto Ricans, several GSNOR SNPs and a haplotype in the 3'UTR were significantly associated with increased risk for asthma and lower bronchodilator responsiveness (P=0.04-0.007). The GSNOR risk haplotype affects expression of GSNOR mRNA and protein, suggesting a gain of function. Furthermore, gene-gene interaction analysis provided evidence of pharmacogenetic interaction between GSNOR and beta2AR gene variants and the response to albuterol in Puerto Rican (P=0.03), Mexican (P=0.15) and combined Puerto Rican and Mexican asthmatics (P=0.003). Specifically, GSNOR+17059*beta2AR+46 genotype combinations (TG+GG*AG and TG+GG*GG) were associated with lower bronchodilator response.Genotyping of GSNOR and beta2AR genes may be useful in identifying Latino individuals, who might benefit from adjuvant therapy for refractory asthma.
Project description:BackgroundThe American Thoracic Society has published general guidelines for sterility when testing for bronchodilator responsiveness. However, the extent to which practicing allergists implement sterility measures is currently unknown.ObjectiveThis study aims to understand the adherence to the American Thoracic Society guidelines for sterility among practicing allergists.MethodsIn 2015, a questionnaire was approved and distributed by the American Academy of Allergy, Asthma & Immunology to all its members. The anonymous responses were recorded and tabulated after a 3-week period.ResultsOf the 6800 allergists who received surveys from the American Academy of Allergy, Asthma & Immunology members, 496 participated in the survey (response rate 7.3%). Using metered dose inhalers with a spacer and nebulizers were the most common bronchodilator administration techniques, as indicated by 59.35% and 58.52% of responses, respectively. Whereas 69.25% of the allergists considered their bronchodilator administration techniques to be sterile, 14.05% did not consider their administration technique to be sterile and 16.70% were unsure. For maintaining sterility, 38.75% of the respondents indicated using a new disposable attachment for reused inhalers, 18.71% indicated using a new inhaler for each patient, and 9.13% reported wiping inhalers with a cleaning agent.ConclusionsWhen asked about the sterility of the techniques used by them, nearly one-third of the allergists either stated that the measures used by them were unsterile or stated that they were were unsure. To increase adherence to sterility measures among North American allergists, promoting guideline awareness and proposing updated guidelines focused on the most common bronchodilator administration techniques is essential.
Project description:BackgroundUnderstanding the effects of interactions between multiple genes and asthma medications may aid in the understanding of the heterogeneous response to asthma therapies.ObjectiveTo identify modulating effects of arachidonate 5-lipoxygenase-activating protein (ALOX5AP) and leukotriene A(4) hydrolase (LTA4H) gene polymorphisms on the drug-drug interaction between leukotriene modifiers and albuterol in Mexicans and Puerto Ricans.MethodsIn a cross-sectional study of 293 Mexicans and 356 Puerto Ricans with asthma, ALOX5AP and LTA4H genes were sequenced, and interactions between gene polymorphisms and bronchodilator responsiveness to albuterol were compared between leukotriene modifier users and nonusers.ResultsIn heterozygotes and homozygotes for the minor allele at LTA4H single nucleotide polymorphism (SNP) rs2540491 and heterozygotes for the major allele at LTA4H SNP rs2540487, leukotriene modifier use was associated with a clinically significant increase in percent change in FEV(1) after albuterol administration of 7.10% (P = .002), 10.06% (P = .001), and 10.03% (P < .001), respectively. Presence of the major allele at ALOX5AP SNP rs10507391 or the minor allele at ALOX5AP SNP rs9551963 augmented this response. When stratified by ethnicity, these findings held true for Puerto Ricans but not Mexicans.ConclusionLTA4H and ALOX5AP gene polymorphisms modify the augmentation of bronchodilator responsiveness by leukotriene modifiers in Puerto Ricans but not Mexicans with asthma.
Project description:Variability in response to short-acting β2-agonists (e.g., albuterol) among patients with asthma from diverse racial/ethnic groups may contribute to asthma disparities. We sought to identify genetic variants associated with bronchodilator response (BDR) to identify potential mechanisms of drug response and risk factors for worse asthma outcomes. Genome-wide association studies of bronchodilator response (BDR) were performed using TOPMed Whole Genome Sequencing data of the Asthma Translational Genomic Collaboration (ATGC), which corresponded to 1136 Puerto Rican, 656 Mexican and 4337 African American patients with asthma. With the population-specific GWAS results, a trans-ethnic meta-analysis was performed to identify BDR-associated variants shared across the three populations. Replication analysis was carried out in three pediatric asthma cohorts, including CAMP (Childhood Asthma Management Program; n = 560), GACRS (Genetics of Asthma in Costa Rica Study; n = 967) and HPR (Hartford-Puerto Rico; n = 417). A genome-wide significant locus (rs35661809; P = 3.61 × 10-8) in LINC02220, a non-coding RNA gene, was identified in Puerto Ricans. While this region was devoid of protein-coding genes, capture Hi-C data showed a distal interaction with the promoter of the DNAH5 gene in lung tissue. In replication analysis, the GACRS cohort yielded a nominal association (1-tailed P < 0.05). No genetic variant was associated with BDR at the genome-wide significant threshold in Mexicans and African Americans. Our findings help inform genetic underpinnings of BDR for understudied minority patients with asthma, but the limited availability of genetic data for racial/ethnic minority children with asthma remains a paramount challenge.
Project description:IntroductionPreterm-born children have their normal in-utero lung development interrupted, thus are at risk of short- and long-term lung disease. Spirometry and exercise capacity impairments have been regularly reported in preterm-born children especially those who developed chronic lung disease of prematurity (CLD) in infancy. However, specific phenotypes may be differentially associated with exercise capacity. We investigated exercise capacity associated with prematurity-associated obstructive (POLD) or prematurity-associated preserved ratio of impaired spirometry (pPRISm) when compared to preterm- and term-controls with normal lung function.Materials and methodsPreterm- and term-born children identified through home screening underwent in-depth lung function and cardiorespiratory exercise testing, including administration of postexercise bronchodilator, as part of the Respiratory Health Outcomes in Neonates (RHiNO) study.ResultsFrom 241 invited children, aged 7-12 years, 202 underwent exercise testing including 18 children with POLD (percent predicted (%)FEV1 and FEV1 /FVC < LLN); 12 pPRISm (%FEV1 < LLN and FEV1 /FVC ≥ LLN), 106 preterm-controls (PTc , %FEV1 ≥ LLN) and 66 term-controls (Tc , %FEV1 > 90%). POLD children had reduced relative workload, peak O2 uptake, CO2 production, and minute ventilation compared to Tc , and used a greater proportion of their breathing reserve compared to both control groups. pPRISm and PTc children also had lower O2 uptake compared to Tc . POLD children had the greatest response to postexercise bronchodilator, improving their %FEV1 by 19.4% (vs 6.3%, 6% 6.3% in pPRISm PTc, Tc , respectively; p < .001).ConclusionPreterm-born children with obstructive airway disease had the greatest impairment in exercise capacity, and significantly greater response to postexercise bronchodilators. These classifications can be used to guide treatment in children with POLD.
Project description:BackgroundThe recommended delivery mode for bronchodilators in bronchodilator responsiveness (BDR) testing remains controversial.ObjectiveTo compare the efficacy of salbutamol administration using a nebulizer versus a metered-dose inhaler (MDI) with spacer in BDR testing.DesignA retrospective study.MethodsThis study examined the data of patients with chronic obstructive pulmonary disease who completed BDR testing between 1 December 2021 and 30 June 2022, at Xiangya Hospital, Central South University. After administering 400 μg of salbutamol through an MDI with spacer or 2.5 mg using a nebulizer, the changes in forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) were analyzed in patients with moderate-to-very severe spirometric abnormalities [pre-bronchodilator FEV1 percentage predicted values (FEV1%pred) ⩽59%]. Significant responsiveness was assessed as >12% and >200 mL improvement in FEV1 and/or FVC or >10% increase in FEV1%pred or FVC percentage predicted values (FVC%pred) from pre- to post-bronchodilator administration.ResultsOf the enrolled 894 patients, 83.2% were male (median age, 63 years). After propensity score matching, 240 pairs of patients were selected. The increment in FEV1 and increased FEV1 relative to the predicted value (ΔFEV1%pred) were significantly higher in patients <65 years and those with severe spirometric abnormalities in the nebulization group than patients in the MDI group (all p < 0.05). Compared with MDI with spacer, patients who used nebulization had a 30 mL greater increase in ΔFEV1 (95% CI: 0.01-0.05, p = 0.004) and a 1.09% greater increase in ΔFEV1%pred (95% CI: 0.303-1.896, p = 0.007) from baseline. According to the > 12% and >200 mL increase criterion, the significant BDR rate with nebulization was 1.67 times higher than that with an MDI with spacer (OR = 1.67, 95% CI: 1.13-2.47, p = 0.009).ConclusionSalbutamol delivered using a nebulizer may be preferable to an MDI with spacer in certain circumstances. Nebulization has the potential to increase responsiveness to salbutamol in BDR testing.