Plasma and bronchoalveolar lavage fluid levels of endothelin-1 in patients with chronic obstructive pulmonary disease and pulmonary hypertension.

BACKGROUND: Secondary pulmonary hypertension (PH) and cor pulmonale are the major clinical cardiovascular complications affecting prognosis in patients with chronic obstructive pulmonary disease (COPD). It is also known that endothelin-1 (ET-1) is a potent vasoconstrictor peptide produced by the pulmonary vascular endothelium, and ET-1 may be implicated in the pathogenesis of PH. OBJECTIVES: The purpose of this study was to investigate the presence of ET-1 in patients with COPD and to assess the correlation of ET-1 levels in the plasma and bronchoalveolar lavage (BAL) fluid (BALF) in COPD patients with or without PH. METHODS: Twenty-two patients with COPD and 15 healthy controls were enrolled in the study. Peripheral venous blood samples were collected in all patients and controls. BAL was obtained in COPD patients, and ET-1 levels were measured by radioimmunoassay in all plasma and BALF samples. RESULTS: Plasma ET-1 levels were 2.46 +/- 0.55 and 1.70 +/- 0.42 pmol/dl in patients with COPD and controls, respectively (p < 0.0001). Sixteen of the 22 patients with COPD (73%) had PH established by echocardiography. The ET-1 level in these patients amounted to 2.59 +/- 0.50 pmol/dl, and it was 2.10 +/- 0.54 pmol/dl in 6 patients with COPD without PH. In COPD patients with and without PH, BALF ET-1 levels were 0.19 +/- 0.08 and 0.24 +/- 0.01 pmol/dl, respectively (p > 0.05). CONCLUSIONS: These results suggest that ET-1 is detectable in both the peripheral blood and BALF of COPD patients, but the levels do not statistically differ between patients with and without PH.