Airway smooth muscle enlargement is associated with protease-activated receptor 2/ligand overexpression in patients with difficult-to-control severe asthma.

BACKGROUND: Asthma is a complex disease with heterogeneous features of airway inflammation and remodeling. The increase in airway smooth muscle (ASM) mass is an essential component of airway remodeling in patients with severe asthma, yet the pathobiological mechanisms and clinical outcomes associated with ASM enlargement remain elusive. OBJECTIVE: We sought to compare ASM area in control subjects and patients with mild-to-moderate or severe asthma and to identify specific clinical and pathobiological characteristics associated with ASM enlargement. METHODS: Bronchial biopsy specimens from 12 control subjects, 24 patients with mild-to-moderate asthma, and 105 patients with severe asthma were analyzed for ASM area, basement membrane thickness, vessels, eosinophils, neutrophils, T lymphocytes, mast cells, and protease-activated receptor 2 (PAR-2). In parallel, the levels of several ASM mitogenic factors, including the PAR-2 ligands, mast cell tryptase, trypsin, tissue factor, and kallikrein (KLK) 5 and KLK14, were assessed in bronchoalveolar lavage fluid. Data were correlated with asthma severity and control both at inclusion and after 12 to 18 months of optimal management and therapy. RESULTS: Analyses across ASM quartiles in patients with severe asthma demonstrated that patients with the highest ASM quartile (median value of ASM area, 26.3%) were younger (42.5 vs ≥50 years old in the other groups, P ≤ .04) and had lower asthma control after 1 year of optimal management (P ≤ .006). ASM enlargement occurred independently of features of airway inflammation and remodeling, whereas it was associated with PAR-2 overexpression and higher alveolar tryptase (P ≤ .02) and KLK14 (P ≤ .03) levels. CONCLUSION: Increase in ASM mass, possibly involving aberrant expression and activation of PAR-2-mediated pathways, characterizes younger patients with severe asthma with poor asthma control.

Health-related quality of life in patients with alpha-1 antitrypsin deficiency: the French experience.

The French registry of patients with alpha-1 antitrypsin deficiency (AATD)-associated emphysema was launched in 2006. Here, we aimed to report on the baseline characteristics of these patients, their health-related quality of life (HRQoL) and factors associated with HRQoL. Another goal was to survey the practices of French physicians regarding augmentation therapy. We included 273 patients with AATD, emphysema, obstructive-pattern [forced expiratory volume in 1 sec/forced volume capacity (FEV1/FVC) < 0.7], FEV1 ≤ 80% predicted. Mean (SD) age was 51.8 (11.1) years, 240 (87.9%) of patients were smokers or ex-smokers, mean (SD) FEV1 was 40.5% (15.7) predicted. Mean (SD) SGRQ score was 49.0 (20.0) and was higher for females than males (52.7 [20.7] vs 46.8 [18.2]; p = 0.01). Dyspnea showed the strongest association with SGRQ score (r = 0.65; p < 0.0001), followed by chronic bronchitis (r = 0.33; p < 0.0001) and wheezing (r = 0.32; p < 0.0001). Number of exacerbations in the year before inclusion was also significantly associated with SGRQ score (r = 0.36; p < 0.0001). The SGRQ score was associated with the 6-min walking distance (r = -0.53, p < 0.0001), FEV1 (% predicted, r = -0.53, p < 0.0001) and DLCO (% predicted, r = -0.52, p < 0.0001). It was also associated with the GOLD 2006 (r = 0.53; p < 0.0001) and GOLD 2011 (r = 0.63; p< 0.0001) classifications and with the BODE index (r = 0.37; p < 0.0001). Age, history of tobacco smoking or current smoking did not show any association with SGRQ total scores. On multivariate analysis, a model including age, chronic bronchitis, dyspnea (MRC scale), diffusing lung capacity and 6-min walking distance explained 57% of the variation in the score. The French registry provides important insights into the clinical characteristics of French patients with AATD-related emphysema.

Performance of the BODE index in patients with α1-antitrypsin deficiency-related COPD.

The BODE (body mass index, airflow obstruction, dyspnoea and exercise capacity) index is used to decide on referral and transplantation of patients with chronic obstructive pulmonary disease (COPD). The BODE index has not been validated in patients with α1-antitrypsin deficiency, who account for 15% of COPD patients undergoing lung transplantation. We sought to validate the BODE index in α1-antitrypsin deficiency-related COPD. We assessed the prognostic value of the BODE index in 191 patients followed from 2006 to 2012 in a French prospective cohort of patients with α1-antitrypsin deficiency. 20 patients died during follow-up and 22 underwent lung transplantation. Survival (95% CI) was 93.0% (91.7-94.3%) at 3 years and 76.0% (72.9-79.1%) at 5 years. The 3-year survival was 97.4% (96.6-98.2%), 98.0% (96.7-99.3%), 87.7% (84.5-90.9%) and 75.3% (66.0-84.6%) for patients with BODE index 0-2, 3-4, 5-6 and 7-10, respectively. Survival discrimination of the BODE index was better than with both forced expiratory volume in 1 s and Global Initiative for Chronic Obstructive Lung Disease classification. Regarding calibration, expected survival by BODE index was noticeably lower than observed survival. The BODE index showed very good survival discrimination in patients with α1-antitrypsin deficiency-related COPD. Larger studies are needed to support its use to drive patient referral for lung transplantation.