RESUMO
Downhill skiing in the elderly increases maximal oxygen uptake (VO2max) and carbohydrate handling, and produces muscle hypertrophy. We hypothesized that adjustments of the cellular components of aerobic glucose combustion in knee extensor muscle, and cardiovascular adjustments, would increase in proportion to VO2max. Nineteen healthy elderly subjects (age 67.5 ± 2.9 years) who completed 28.5 days of guided downhill skiing over 3 months were assessed for anthropometric variables, cardiovascular parameters (heart rate, hematocrit), VO2max, and compared with controls (n = 20). Biopsies of vastus lateralis muscle were analyzed for capillary density and expression of respiratory chain markers (NDUFA9, SDHA, UQCRC1, ATP5A1) and the glucose transporter GLUT4. Statistical significance was assessed with a repeated analysis of variance and Fisher's post-hoc test at a P value of 5%. VO2max increased selectively with ski training (+7 ± 2%). Capillary density (+11 ± 5%) and capillary-to-fiber ratio (12 ± 5%), but not the concentration of metabolic proteins, in vastus lateralis were increased after skiing. Cardiovascular parameters did not change. Fold changes in VO2max and capillary-to-fiber ratio were correlated and were under genetic control by polymorphisms of the regulator of vascular tone, angiotensin converting enzyme. The observations indicate that increased VO2max after recreational downhill ski training is associated with improved capillarity in a mainly recruited muscle group.
Assuntos
Proteínas Mitocondriais/metabolismo , Músculo Quadríceps/irrigação sanguínea , Músculo Quadríceps/metabolismo , Esqui/fisiologia , Adaptação Fisiológica , Idoso , Capilares/anatomia & histologia , Capilares/fisiologia , Complexo I de Transporte de Elétrons/metabolismo , Complexo II de Transporte de Elétrons/metabolismo , Complexo III da Cadeia de Transporte de Elétrons/metabolismo , Feminino , Transportador de Glucose Tipo 4/metabolismo , Frequência Cardíaca , Hematócrito , Humanos , Masculino , ATPases Mitocondriais Próton-Translocadoras/metabolismo , Fibras Musculares Esqueléticas/citologia , Neovascularização Fisiológica , Fatores Acopladores da Fosforilação Oxidativa/metabolismo , Consumo de Oxigênio , Peptidil Dipeptidase A/genética , Polimorfismo Genético , Músculo Quadríceps/anatomia & histologiaRESUMO
Among the wide spectrum of congenital abnormalities of coronary arteries, a single coronary artery is often confused with an ectopic coronary artery connected with the contralateral coronary artery. Both abnormalities are characterized by a single coronary ostium, but they differ by the lack or not of an initial ectopic course. The prognosis of anomalous connections of coronary arteries depends mainly on the type of the initial course in relation to other cardiac structures. Therefore, the distinction between a single coronary artery and an ectopic coronary artery connected with the contralateral artery is of importance.