Pulmonary arterial hypertension and continuous injury of alveolar epithelial cells in COPD

Abstract

Pulmonary arterial hypertension (PAH) does not occur in all very severe chronic obstructive pulmonary disease (COPD). We studied the hypothesis that PAH would be related to COPD with continuous injury to the alveolar epithelial cells. We evaluated levels of serum surfactant protein -A (SP-A) and SP-D as markers of alveolar epithelial cell injury. Twelve patients with COPD, all ex-smokers (76.9±7.9 age, C reactive protein (CRP) 0.62±0.8mg/dL, forced expiratory volume in 1 s (FEV 1 ) 0.97±0.39L, FEV 1 /forced vital capacity(FVC) 0.45±0.15, FEV 1 %predicted 50.4±21.3%), were included. All patients who underwent lung function testing and echocardiography twice after an interval of 0 months and more than two months were reviewed from August 1, 2013, to January 23, 2016. PAH was defined as the estimated systolic pulmonary artery pressure (sPAP)≥40mmHg at rest. The PAH group consisted of patients who had at least had PAH at one time, and the non-PAH group consisted of patients who had never had PAH. Eight patients were in the PAH group. In the PAH and non-PAH groups, levels of SP-A and SP-D were 57.4±24.2ng/mL and 60.4±36.0ng/mL versus 32.2±2.7ng/mL and 26.4±11.0ng/mL, respectively, and differed significantly between the PAH group and the non-PAH group (by Mann-Whitney9s U test, p 1 (0.97±3.8L versus 0.98±0.42L), FEV 1 /FVC(0.46±0.18 versus 0.42±0.06), and FEV 1 %predicted(52.7±23.2% versus 45.7±17.4%) in the PAH and non-PAH groups. This report suggests that PAH might be related to continuous injury to alveolar epithelial cells.