Gene polymorphisms of endothelial nitric oxide synthase enzyme associated with pulmonary hypertension in patients with COPD.

In this cross-sectional controlled study, we aimed to investigate the role of polymorphisms of the angiotensin-converting enzyme (ACE) and endothelial nitric oxide synthase (eNOS) genes on pulmonary hypertension (PH) in patients with chronic obstructive pulmonary disease (COPD). Forty-two (41 male, 1 female, mean age: 62 +/- 7 years) COPD patients and 40 (all male, mean age: 60 +/- 8 years) healthy controls were included. Respiratory function tests, arterial blood gases, and echocardiographic examinations were performed. ACE and eNOS genotypes were determined using PCR. The ACE and eNOS genotype distribution was not significantly different between COPD patients and controls. On comparing pulmonary artery pressures in different eNOS genotypes, the mean pulmonary artery pressure (Ppa) in patients with the BB genotype was significantly higher than in patients with the nonBB genotypes (41.3 +/- 17.7 mmHg vs. 27.3 +/- 11.2 mmHg, P = 0.02). However, there was no difference in ACE genotype distributions between COPD patients with and without pulmonary hypertension. In stepwise linear regression analysis for predicting pulmonary artery pressure, PaO2 and polymorphism of eNOS gene were found to be independent variables. In conclusion, BB-type polymorphism of the eNOS gene has been associated with PH in addition to hypoxemia. However, ACE gene polymorphism was not found to be associated with PH.