Influence of T-786C polymorphism on the promoter activity of eNOS

Interplay between polymorphisms in the endothelial nitric oxide synthase (eNOS) gene and metabolic syndrome in determining the risk of ischemic stroke in Koreans

BACKGROUND

Endothelial nitric oxide synthase (eNOS) gene variants are known to play a role in atherosclerotic development. However, whether interplay between eNOS polymorphisms and metabolic syndrome (MetS) affects ischemic stroke (IS) risk has yet to be discovered. We investigated whether the combined effects of eNOS polymorphisms and MetS influence ischemic stroke risk in Koreans.

METHODS

We genotyped the eNOS -922A>G, -786T>C, 4a4b, and 894G>T polymorphisms in 531 IS cases and 502 controls using polymerase chain reaction-amplified DNA. We then investigated whether the presence of MetS and the number of MetS risk factors worked with eNOS polymorphisms to influence IS risk.

RESULTS

IS patients had a significantly higher prevalence of MetS than controls [adjusted odds ratio (AOR)=2.943, 95% confidence interval (CI), 2.256-3.840, P<0.0001], and MetS prevalence did not differ between stroke subtypes. The 894GT+TT genotypes were positively associated with IS (AOR=1.670, 95% CI, 1.208-2.308, P=0.002), and the -786TC+CC genotypes showed co-morbidity with MetS (AOR=1.448, 95% CI, 1.401-2.015, P=0.028). Among subjects with three or more MetS risk factors, the highest AOR value (28.490, 95% CI, 3.162-256.688) was observed for the eNOS -786TC+CC genotypes.

CONCLUSIONS

The eNOS 894T allele and interplay between the eNOS -786C allele and MetS may predispose Koreans to IS.

Efeitos do exercício físico no controle da hipertensão arterial em idosos: uma revisão sistemática

O exercício físico é uma das principais terapêuticas utilizadas para o paciente hipertenso, pois reduz a pressão arterial (PA) e os fatores de risco cardiovasculares, diminuindo a morbimortalidade. OBJETIVO: Analisar os efeitos do exercício físico na PA de idosos hipertensos, com base nos resultados de pesquisas empíricas realizadas no período de 2000 a 2010. METODOLOGIA: Revisão sistemática de estudos experimentais, em inglês, português e espanhol, nas bases eletrônicas MEDLINE, PubMed, Lilacs, Cochrane e PEDro, publicados entre 2000 e 2010, utilizando os descritores hipertensão, atividade física, exercício físico, idoso, exercício aeróbio e treinamento de resistência. RESULTADOS: Foram encontrados 19 artigos e incluídos 12 artigos, sendo divididos em categorias temáticas: exercício aeróbico (6 artigos), exercício resistido (4), exercício aeróbico associado ao resistido (2). Entre os exercícios aeróbicos, três artigos evidenciaram redução na pressão arterial sistólica (PAS) e pressão arterial diastólica (PAD). Três artigos afirmam que treinamento resistido reduz significativamente os valores de PAS em repouso e pressão arterial média (PAM), apenas um artigo não registrou uma redução significativa na PAD e frequência cardíaca (FC) de repouso. A utilização dos exercícios aeróbicos associados aos resistidos foram superiores aos demais, pois apontaram reduções significativas na PAS, PAD, PAM e FC de repouso, confirmando as recomendações da VI Diretriz Brasileira de Hipertensão Arterial, mas os estudos em idosos são escassos. CONCLUSÃO: Esta revisão confirma os benefícios oriundos da prática do exercício físico na redução da PA após o exercício em idosos hipertensos.

Effects of aerobic exercise on the blood pressure, oxidative stress and eNOS gene polymorphism in pre-hypertensive older people

The polymorphisms of endothelial nitric oxide synthase (eNOS) are associated with reduced eNOS activity. Aerobic exercise training (AEX) may influence resting nitric oxide (NO) production, oxidative stress and blood pressure. The purpose of this study was to investigate the effect of AEX on the relationship among blood pressure, eNOS gene polymorphism and oxidative stress in pre-hypertensive older people. 118 pre-hypertensive subjects (59 ± 6 years) had blood samples collected after a 12 h overnight fast for assessing plasma NO metabolites (NOx) assays, thiobarbituric acid reactive substances (T-BARS) and superoxide dismutase activity (ecSOD). eNOS polymorphism (T-786C and G-894T) was done by standard PCR methods. All people were divided according to the genotype results (G1: TT/GG, G2: TT/GT + TT, G3: TC + CC/GG, G4: TC + CC/GT + TT). All parameters were measured before and after 6 months of AEX (70% of VO(2 max)). At baseline, no difference was found in systolic and diastolic blood pressure, ecSOD and T-BARS activity. Plasma NOx levels were significantly different between G1 (19 ± 1 μM) and G4 (14.2 ± 0.6 μM) and between G2 (20.1 ± 1.7 μM) and G4 (14.2 ± 0.6 μM). Therefore, reduced NOx concentration in G4 group occurred only when the polymorphisms were associated, suggesting that these results are more related to genetic factors than NO-scavenging effect. After AEX, the G4 increased NOx values (17.2 ± 1.2 μM) and decreased blood pressure. G1, G3 and G4 decreased T-BARS levels. These results suggest the AEX can modulate the NOx concentration, eNOS activity and the relationship among eNOS gene polymorphism, oxidative stress and blood pressure especially in C (T-786C) and T (G-894T) allele carriers.