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: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: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: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: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.
Project description:This paper proposes a new methodology to quantify patterns of egg shape variation using geometric morphometrics of three-dimensional landmarks captured on digitally reconstructed eggshells and demonstrates its performance in capturing shape variation at multiple biological levels. This methodology offers unique benefits to complement established linear measurement or two-dimensional (2D) contour profiling techniques by (i) providing a more precise representation of eggshell curvature by accounting for variation across the entire surface of the egg; (ii) avoids the occurrence of correlations from combining multiple egg shape features; (iii) avoids error stemming from projecting a highly-curved three-dimensional (3D) object into 2D space; and (iv) enables integration into 3D workflows such as finite elements analysis. To demonstrate, we quantify patterns of egg shape variation and estimate morphological disparity at multiple biological levels, within and between clutches and among species of four passerine species of different lineages, using volumetric dataset obtained from micro computed tomography. The results indicate that species broadly have differently shaped eggs, but with extensive within-species variation so that all four-focal species occupy a range of shapes. Within-species variation is attributed to between-clutch differences in egg shape; within-clutch variation is surprisingly substantial. Recent comparative analyses that aim to explain shape variation among avian taxa have largely ignored potential biases due to within-species variation, or use methods limited to a narrow range of egg shapes. Through our approach, we suggest that there is appreciable variation in egg shape across clutches and that this variation needs to be accounted for in future research. The approach developed in this study to assess variation in shape is freely accessible and can be applied to any spherical-to-conical shaped object, including eggs of non-avian dinosaurs and reptiles through to other extant taxa such as poultry.
Project description:BackgroundA thorough analysis of continuous adventitious sounds (CAS) can provide distinct and complementary information about bronchodilator response (BDR), beyond that provided by spirometry. Nevertheless, previous approaches to CAS analysis were limited by certain methodology issues. The aim of this study is to propose a new integrated approach to CAS analysis that contributes to improving the assessment of BDR in clinical practice for asthma patients.MethodsRespiratory sounds and flow were recorded in 25 subjects, including 7 asthma patients with positive BDR (BDR+), assessed by spirometry, 13 asthma patients with negative BDR (BDR-), and 5 controls. A total of 5149 acoustic components were characterized using the Hilbert spectrum, and used to train and validate a support vector machine classifier, which distinguished acoustic components corresponding to CAS from those corresponding to other sounds. Once the method was validated, BDR was assessed in all participants by CAS analysis, and compared to BDR assessed by spirometry.ResultsBDR+ patients had a homogenous high change in the number of CAS after bronchodilation, which agreed with the positive BDR by spirometry, indicating high reversibility of airway obstruction. Nevertheless, we also found an appreciable change in the number of CAS in many BDR- patients, revealing alterations in airway obstruction that were not detected by spirometry. We propose a categorization for the change in the number of CAS, which allowed us to stratify BDR- patients into three consistent groups. From the 13 BDR- patients, 6 had a high response, similar to BDR+ patients, 4 had a noteworthy medium response, and 1 had a low response.ConclusionsIn this study, a new non-invasive and integrated approach to CAS analysis is proposed as a high-sensitive tool for assessing BDR in terms of acoustic parameters which, together with spirometry parameters, contribute to improving the stratification of BDR levels in patients with obstructive pulmonary diseases.
Project description:BackgroundConventional lung function parameters, such as forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1) and inspiratory capacity (IC) are often used to assess the therapeutic outcomes of bronchodilators, but they lack sensitivity. A novel indicator, namely efficiency of neural respiratory drive (NRD), may objectively evaluate the physiological changes in patients with chronic obstructive pulmonary disease (COPD). We investigated whether this indicator could be used to more accurately assess the responsiveness to inhaled bronchodilators.MethodsThirty-six subjects with moderate-to-severe COPD were randomized into group A (n=18) and group B (n=18). Participants in group A inhaled 400 µg placebo, 400 µg salbutamol and 80 µg ipratropium in sequence whereas those in group B had the salbutamol and ipratropium reversed. At different time points after administration of placebo or bronchodilators, evaluated indices included FEV1, FVC, IC, root mean square (RMS) of diaphragm electromyogram (EMGdi), and efficiency of NRD [herein defined as the ratio of minute ventilation (VE) to RMS, or VE/RMS].ResultsFEV1, FVC, IC, RMS, and VE/RMS significantly improved after inhaled bronchodilators and VE/RMS had the largest improvement among five indices. The detection efficiency of VE/RMS was greater than FEV1, FVC, IC (all P<0.05), but not different from RMS. The accuracy and sensitivity of VE/RMS were significantly higher than FEV1, FVC, IC, and RMS (all P<0.05).ConclusionsEfficiency of NRD may be a sensitive tool to evaluate the efficacy of inhaled bronchodilators in COPD.