Gene polymorphism of the endothelial nitric oxide synthase enzyme and pulmonary hypertension in patient with chronic obstructive pulmonary disease

OBJECTIVE: To investigate the relationship between the gene polymorphism of the endothelial nitric oxide synthase enzyme (eNOSG894T) with pulmonary hypertension of Chinese patient with chronic obstructive pulmonary disease (COPD). METHODS: Fifty normal volunteers (29 male, 21 female, mean age 67 +/- 3) and 50 patients with COPD complicated by pulmonary hypertension (31 male, 19 female, mean age 69 +/- 10) were included in the study. Lung function, arterial blood gases, and echocardiographic examination were performed. The genotype of eNOSG894T was determined with PCR. RESULTS: The frequencies of GT + FT genotype and T allele were significantly greater in the patients compared to the controls. The levels of NOx and NOx/ET were lower in the GT + T genotype [(48 +/- 8) micromol/L, (0.51 +/- 0.20)] than in the GG genotype [(60 +/- 24) micromol/L, (1.43 +/- 0.64)] of COPD. The level of ET was higher in the GT + TT genotype [(104 +/- 38) microg/L] than in the GG genotype [(50 +/- 26) microg/L] of COPD patients. The mean systolic pulmonary artery pressure was higher in the GT + TT genotype [(57 +/- 15) mm Hg, 1 mm Hg = 0.133 kPa] than in the GG genotype [(47 +/- 10) mm Hg] of COPD patients. In stepwise logistic regression analysis for predicting pulmonary artery pressure, the polymorphism of eNOS gene, the level of Nox and smoking were found to be independent variables. CONCLUSION: The G894T polymorphism of eNOS gene is associated with pulmonary hypertension of COPD in a Chinese population. T allele may be involved in the etiology of pulmonary hypertension with COPD by reducing NO release of the endothelium.