Polymorphisms in the endothelial nitric oxide gene are associated with lower vascular reactivity after a maximal dynamic exercise

Abstract

Our aim was to investigate the influence of three polymorphisms in the endothelial nitric oxide (eNOS) gene (−786T>C, intron 4b4a and 894G>T), on the vascular reactivity (VR) to an ischemic stimulus. We evaluated 106 healthy, sedentary, non-obese women (31 ± 9 years). Genotypes were determined by PCR-RFLP and haplotypes inferred based on the Bayesian method. VR was considered the change in forearm vascular conductance [blood flow (plethysmography) divided by mean blood pressure (auscultation); ml/100ml.min.100mmHg] provoked by 5 min of ischemia before, 10 and 60 min after a maximal cardiopulmonary exercise test (CPET). VR increased 10 min after the CPET in the entire sample (p<0.001 vs. baseline). Subjects with polymorphic alleles at position −786 and intron 4 had a trend for lower VR 10 min after the CPET versus wild type counterparts (−786CC: 7.7 ± 1.5 vs. −786TT: 10.1 ± 0.6, p = 0.06; 4b4a/4a4a: 8.5 ± 5.9 vs. 4b4b: 10.0 ± 0.5, p = 0.06). In addition, a haplotype with polymorphic alleles at positions −786 and 894 (−786C/4b/894T; 8.9 ± 0.7) and another with polymorphic allele in intron 4 (−786T/4a/894G; 7.5 ± 1.3) had lower VR 10 min after the CPET versus a haplotype with wild type alleles (−786T/4b/894G; 10.1 ± 0.4, p = 0.02 and 0.05, respectively). Thus, these results suggest that the −786T>C, intron 4b4a and 894G>T polymorphisms are associated with lower VR after a maximal dynamic exercise. Support: CAPES, CNPq and FAPERJ.