Exercise improves endothelial function: a local analysis of production of nitric oxide and reactive oxygen species.

This study aimed at investigating the acute effects of aerobic exercise on endothelium-dependent vasomotor function of rat aorta, as well as mechanisms involved in endothelial nitric oxide (NO) bioactivity. Wistar rats were assigned to either a resting control (C, n = 21) or acutely exercised (E, n = 21) groups (60 min, 55-60% of maximum speed). After exercise, thoracic aorta was excised and cut into rings. Two rings were promptly applied to evaluate vasomotor function and the rest of aorta was used for additional measurements. Acute exercise significantly improved maximum ACh-induced relaxation (C, 91.6 ± 1.2 vs. E, 102.4 ± 1.7%, p < 0.001) and sensitivity to ACh (C, -7.3 ± 0.06 vs. E, -7.3 ± 0.02 log M, p < 0.01), and was accompanied by significantly increases on serine1177 eNOS phosphorylation, reflecting its enhanced activation. However, acute exercise also enhanced both superoxide and hydrogen peroxide production, as assayed by dihydroethidium oxidation, lucigenin chemiluminescence and Amplex Red assays. We also provided evidence for Nox2 NADPH oxidase (Nox) activation through gp91dstat-mediated inhibition of superoxide signals. Enhanced arterial relaxations associated with acute exercise were nearly-completely prevented by catalase, suggesting a role for paracrine hydrogen peroxide. Despite increased detectable oxidant generation, cellular oxidative stress was not evident, as suggested by unaltered GSH:GSSG ratio and lipid hydroperoxides. Collectively, these results demonstrate that one bout of moderate aerobic exercise improves endothelial function by increasing NO bioavailability, while superoxide and hydrogen peroxide are generated in a controlled fashion.

[Aortic stenosis and coronary disease. Analysis of risk factors]. / Estenose aórtica e doença coronariana. Análise dos fatores de risco.

OBJECTIVE: To analyze clinical laboratorial aspects of the presence of coronary disease in patients with aortic stenosis and evaluate the influence of risk factors in the development of obstructive coronary disease. METHODS: We studied 65 patients who had severe aortic stenosis with an indication for surgery, ages 51 to 85 years, 40 of them women. The coronary angiography assessment resulted in two groups: 26 (40%) with obstructive coronary disease and 39 (60%) with no coronary artery lesion. Personal antecedents for coronary disease (smoking, dyslipidemia, diabetes mellitus, arterial hypertension, family antecedents, sedentarism, and alcoholism) were analyzed. Additionally, the following assessments were made: electrocardiogram, echocardiogram with Doppler, and laboratory tests (blood glucose, total cholesterol and fractions, triglycerides, Apo-A1 and B, fibrinogen, lipoprotein (a) and fraction of triglycerides and cholesterol removal in both groups. RESULTS: In the age analysis, the group with obstructive coronary disease belonged to an older age range with statistical significance (p<0.0001). Signs of ischemia of the anterior wall identified on the electrocardiogram showed a significant relationship with the obstruction of an anterior interventricular artery (p<0.002). The univariate analysis showed a significant difference between the groups regarding averages of the aortic (p= 0.041), HDL (p=0.042), and fibrinogen (p=0.047) gradients. The group with coronary disease presented an average gradient and HDL level lower than the group without obstructive coronary disease. For the fibrinogen variable, the average in the group with no coronary disease was lower compared to that of the coronariopathy group. The multivariate logistic regression analysis showed fibrinogen levels as an independent variable for coronary disease (p<0.039). CONCLUSION: Fibrinogen was an independent risk factor for the association between obstructive coronary disease and aortic stenosis.

Estenose aórtica e doença coronariana: análise dos fatores de risco / Aortic stenosis and coronary disease: analysis of risk factors

OBJETIVO: Analisar aspectos clínico-laboratoriais da presença de doença coronariana em pacientes portadores de estenose aórtica e analisar a influência de fatores de risco para o desenvolvimento de coronariopatia obstrutiva. MÉTODOS: Estudamos 65 pacientes portadores de estenose aórtica severa com indicação de cirurgia, com idade entre 51 a 85 anos, entre os quais havia 40 mulheres. Da realização da cinecoronariografia resultaram dois grupos: 26(40 por cento) com coronariopatia obstrutiva e 39(60 por cento) sem lesões em artérias coronárias. Foram analisados os antecedentes pessoais para doença coronariana (hábito de fumar, dislipidemia, diabetes mellitus, hipertensão arterial, antecedentes familiares, sedentarismo e alcoolismo), eletrocardiograma, ecocardiograma com Doppler e exames laboratoriais (glicemia, colesterol total e frações, triglicérides, Apo A1 e B, fibrinogênio, lipoproteina(a) e taxa fracional de remoção de triglicérides e colesterol nos dois grupos. RESULTADOS: Na análise da idade, o grupo com coronariopatia obstrutiva apresentou faixa etária mais elevada com significância estatística (p<0,0001). A identificação de sinais de isquemia em parede anterior no eletrocardiograma apresentou relação significante com obstrução em artéria interventricular anterior (p<0,002). A análise univariada mostrou diferença significante entre os grupos em relação às médias das variáveis gradiente aórtico (p= 0,041), HDL (p=0,042) e fibrinogênio (p=0,047). O grupo com doença coronariana apresentou média do gradiente e HDL menor que os sem coronariopatia obstrutiva. Na variável fibrinogênio, o grupo sem doença coronariana apresentou média com níveis menores comparados aos dos portadores de coronariopatia. A análise multivariada pelo método da regressão logística mostrou como variável independente para coronariopatia os níveis de fibrinogênio ( p<0,039). CONCLUSÃO: O fibrinogênio foi fator de risco independente para a associação de coronariopatia obstrutiva com estenose aórtica.