Impact of endothelial nitric oxide synthase gene polymorphisms on hemodynamic after a bout of maximal dynamic exercise

Abstract

Polymorphisms in the endothelial nitric oxide synthase (eNOS) gene (NOS3) have been associated with lower eNOS expression and activation, which can lead to impairment in eNOS related traits. Thus, we investigated the individual (genotype analysis) and combined (haplotype analysis) impact of three polymorphisms in the NOS3 (−786T>C, 4b4a and 894G>T) on hemodynamic variables. Sedentary, non‐obese, healthy subjects were enrolled [n = 93, age 31 ± 9 years (mean ± SD)]. Genotypes were determined by PCR‐RFLP and haplotypes were inferred by a Bayesian based algorithm. Heart rate (ECG) and blood pressure (BP; finger photoplethismography) were continuously measured during 10 min in the supine position before [baseline (BL)], 10, 60 and 120 min after a maximal cardiopulmonary exercise test. Stroke volume was estimated by the Model Flow method. Then, cardiac output (CO) and total peripheral resistance (TPR) were calculated. There was no difference between subjects in genotype analysis. However, subjects with haplotype containing the polymorphisms −786T>C and 4b4a had higher systolic BP at 10, 60 and 120 min after exercise than subjects with wild haplotype (P < 0.05), which occurred due to higher CO (P < 0.05), while TPR was similar between groups (P > 0.05). In conclusion, NOS3 haplotype containing the polymorphisms −786T>C and 4b4a was associated with impaired hemodynamic response after a bout of maximal dynamic exercise.