Correlation Between Intron 4 Polymorphism of the Endothelial Nitric Oxide Synthase Gene and Cardiovascular Risk with the Numbers of Circulating Endothelial Progenitor Cells in Healthy Subjects.

In the present study, we investigated the relationship between an important 27 bp repeat polymorphism in intron 4 of eNOS and numbers of circulating EPCs in presence of cardiovascular disease (CVD) risk factors in a group of healthy human volunteers. The study comprised of 45 healthy subjects (30-50 years). These subjects had various degrees of CVD risk but no history of CVD. The repeat polymorphism of eNOS was detected by polymerase chain reaction and EPC levels were analyzed by flow cytometry. We observed a good association between the intronic 4 mutant a/b genotype and the combined Framingham risk factor score in our subjects (χ2 = 3.2, P = 0.07). EPC numbers in subjects with mutant eNOS a/b genotype were also less than those observed in subjects with normal eNOS b/b genotype (P = 0.06). Interestingly, subjects with eNOS a/b genotype showed a significant inverse correlation between framingham risk score and EPC numbers (R = -0.57, P < 0.05). The study suggests that the presence of CVD risk factors in subjects with eNOS intron 4 polymorphism results in reduced number of circulating EPCs, which may significantly predispose them to CVD and aberrant endothelial repair.