Objective: to investigate the expression of prostacyclin in lungs from patients with chronic obstructive pulmonary disease (COPD).
Methods: the lung tissues were obtained from 12 patients with COPD and 10 patients without COPD. The apoptosis of pulmonary vascular endothelial cells was analyzed quantitatively using TdT-mediated dUTP nick end labeling (TUNEL). The expression of PGI2-S protein was assessed by immunohistochemistry of paraffin-embedded tissues. 6-keto Prostaglandin F1a, the stable metabolite of PGI2, was measured by enzyme-linked immunosorbent assay in whole-lung tissue extracts. The data distributed normally were expressed as x(-) +/- s, and the independent-samples t test was used for comparison of means.
Results: the apoptotic index (AI) of endothelial cells of medium and small-sized vessels in patients with COPD group [(12.9 +/- 2.0)%, (11.4 +/- 1.4)%] were significantly higher than that of patients without COPD [(6.1 +/- 1.2)%, (5.9 +/- 0.4)%]. In patients without COPD, PGI2-S protein expression in medium vessels and small-sized vessels was (95.4 +/- 2.1)% and (82.3 +/- 7.4)% respectively, and the value was (95.5 +/- 2.2)% in airway epithelial cells. In patients with COPD, PGI2-S expression in medium vessels and small-sized vessels decreased remarkably [(55.2 +/- 9.8)% and (42.3 +/- 5.1)% respectively], and exhibited a marked reduction in airway epithelial cells (31.8 +/- 5.2)%. The level of 6-keto Prostaglandin F1a was significantly lower in patients with COPD (2.6 +/- 0.4)microg/L compared with patients without COPD (16.2 +/- 2.8)microg/L.
Conclusion: abnormal apoptosis exists in pulmonary vascular endothelial cells in patients with COPD. In patients with COPD, the expression of PGI2-S and the level of 6-keto Prostaglandin F1a in lung tissues were decreased. The results suggest that abnormal apoptosis, reduction of PGI2-S expression and PGI2 may be important histological markers for pulmonary endothelial cell dysfunction in COPD and may be involved in the pathogenesis of the disease.