Effect of aerobic exercise training on cGMP levels and blood pressure in treated hypertensive postmenopausal women

Abstract The second messenger cGMP has been largely studied as a therapeutic target in a variety of disorders such as erectile dysfunction, arterial hypertension and heart failure. Evidence has shown thatcGMP activators are less efficient in estrogen-deficiency animals, but no studies exist involving non-pharmacological approacheson NO/cGMP signaling pathway in hypertensive postmenopausal women. The aim of this study is to examine NO/cGMP pathway, redox state and blood pressure in trained treatedhypertensive (HT) postmenopausal women comparing with normotensive (NT) group. The rationale for that is most of HT patients is encouraged by physician to perform exercise associated with pharmacological treatments.Aerobic exercise training (AET) consisted of 24 sessions, 3 times/week.Parameters were evaluated at baseline and after AET for both groups (HT=28; NT=33).In treatedHT group, AET was significantly effective in increasing cGMP concentrations (28%) accompanied by an up-regulation of SOD (97%) and catalase activity (37%). In NT group, we found an increasein SOD activity (58%). TreatedHT postmenopausal women were still responsive to AET increasing cGMP levels and up-regulating antioxidant system. It should also be emphasized that these findings provide information on the circulating biomarkers that might delay the developing of cardiovascular events in this particular population.(AU)

Assessment of endothelial function by flow-mediated dilation in diabetic patients: effects of physical exercise

The endothelium is now recognized as an endocrine organ that acts to maintain vascular homeostasis regulating the vascular tone and structure. The endothelial cells synthetize a variety of mediators among them, the main agent is the nitric oxide (NO), a potent vasodilator. NO exerts its protective role preventing leukocyte adhesion and migration, expression of adhesion molecules, platelet aggregation, cell proliferation, and promoting the relaxation of smooth muscle cells. On the other hand, endothelial dysfunction present in many chronic diseases such as atherosclerosis, coronary artery disease, peripheral artery disease, hypertension and diabetes mellitus, is characterized by reduced NO bioavailability. Thus, a few decades ago, measurement of endothelial function has emerged as valuable tool that provides insights in the pathophysiological mechanisms, opportunity to identify early disease and cardiovascular risk, preventing future events or avoiding the progression of the disease. Diabetic patients, particularly, have been a target to apply this technique, mainly because this condition has been related with an impairment of endothelium-dependent dilation and it is believed that the endothelium dysfunction is the basis of diabetes complications such as coronary artery disease and accelerated atherosclerosis. In addition, cardiovascular complications represent the leading cause of morbidity and death in diabetes mellitus. Besides pharmacological therapy, lifestyle modifications have been recommended by specific organizations as a strategy to improve the endothelial function or even prevent the development of diabetes. The aim of this mini eview is to give an update about the importance of endothelium, most common non-invasive technique to evaluate its function, and to summarize some mechanisms involved in endothelial dysfunction and the beneficial effects of exercise in diabetes mellitus.

Use of sample size calculation in scientific research in Brazilian Physical Education journals / Emprego do cálculo amostral em pesquisas científicas de periódicos nacionais de Educação Física

The mistaken use of biostatistics in scientific research involves methodological errors both in the research itself as in its analyses. Among these, the lack of sample size calculation, considered essential for validation and credibility of results, is often found. The aim of the study was to determine how often sample size calculation is used in articles published in Physical Education national journals. The study included only national scientific journals ranked as A1 and B2 by the Coordination of Improvement of Higher Education Personnel (CAPES), which analyzed only articles available in full and published in the period from 2010 to 2012. Review articles, letter to the editor, points of view and original articles that did not perform any statistical analysis were excluded. Approximately 15 % of articles analyzed performed sample size calculation and no difference between these proportions over the years were identified. Differences between Physical Education subareas (education, health and sport) were observed, being lower in sport (p = 0.001) compared to other subareas. Journals classified as B2 showed higher use of sample size calculation in relation to those classified as B1 (p = 0.013) and A2 (p = 0.007). The use of sample size calculation in scientific research published in Physical Education national journals in the period from 2010 to 2012 was not satisfactory, especially in sport subarea. Moreover, no evolution on the use of sample size calculation over the years analyzed was observed.

O emprego equivocado da bioestatística nas pesquisas científicas implica em erros metodológicos tanto na condução quanto nas análises das mesmas. Dentre estes, a ausência do cálculo amostral, considerado primordial para validação e credibilidade dos resultados, é frequentemente encontrado. O objetivo do estudo foi verificar com que frequência o cálculo amostral é empregado nos artigos publicados em periódicos nacionais de Educação Física. Foram incluídos no estudo somente periódicos científicos nacionais classificados entre A1 e B2 pela Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), dos quais foram analisados somente artigos originais disponíveis na íntegra e publicados no período de 2010 a 2012. Foram excluídos do estudo artigos de revisão, carta ao editor, ponto de vista e artigos originais que não realizaram nenhum tipo de análise estatística. Aproximadamente 15% dos artigos analisados realizaram cálculo amostral; não houve diferença entre as proporções destes ao longo dos anos. Observou-se diferença entre as subáreas da Educação Física (educação, saúde e esporte), sendo menor na subárea esporte (p = 0,001) em relação às demais. Os periódicos classificados como B2 apresentaram maior uso do cálculo amostral em relação àqueles classificados como B1 (p = 0,013) e A2 (p = 0,007). O emprego do cálculo amostral em pesquisas científicas publicadas em periódicos nacionais de Educação Física no período de 2010 a 2012 não foi satisfatório, especialmente na subárea esporte. Além disso, não foi observada uma evolução do uso do cálculo amostral ao longo dos anos analisados.

Effect of swimming training on stress-related metabolic parameters of diabetic and non-diabetic rats / Efeito do treinamento de natação sobre estresse metabólico de ratos diabéticos e não diabéticos

Physical training can be an useful strategy to attenuate the stress markers concentrations and hyperglycemia on type 1 diabetic rats. Thus, the purpose of the present study was to investigate the effects of swimming training on metabolic parameters and stress markers in diabetic and non-diabetic rats. Twenty-four adult male Wistar rats were recruited. The rats were randomly divided into four groups, sedentary control (SC), trained control (TC), sedentary diabetic (SD), and trained diabetic (TD). The diabetic rats received alloxan monohydrate and the trained rats swam for 60 minutes five times per week. The training load was 3.5% and 5% of body weight to diabetic and non-diabetic rats, respectively. After the euthanasia, blood samples for determination of corticosterone, insulin, and glucose levels were collected, and the adrenal weight, adrenal cholesterol concentration, gastrocnemius glycogen concentration, and muscle total protein content were also determined. To compare the groups, a variance analysis was used with Tukey´s post-hoc. The significance level of 5% was adopted. The adrenal weight was higher in SD (17.2±0.6g) than the other groups (SC: 12.2±0.8g; TC: 13.7±0.6g; TD: 14.3±0.8g), and TD had similar values of TC. The corticosterone level of SD was higher than SC and TC. The serum glucose was higher in the diabetic groups and insulin was lower in these groups. Six weeks of swimming training was efficient to reduce stress markers concentration in type 1 rats. Training may be a good tool to avoid the reduction on muscle protein content in type 1 diabetic rats.

Treinamento físico pode ser uma estratégia útil para atenuar as concentrações de marcadores de estresse e hiperglicemia em ratos diabéticos tipo 1. Assim, objetivo do estudo foi investigar o efeito do treinamento de natação sobre os parâmetros metabólicos e marcadores de estresse em ratos diabéticos e não diabéticos. Foram selecionados vinte e quatro ratos machos Wistar divididos em quatro grupos, controle sedentário (SC), controle treinado (TC), diabético sedentário (SD) e diabético treinado (TD). A indução de diabetes foi por aloxana monoidratada. Os ratos foram submetidos a 60 minutos de natação cinco vezes por semana com carga de 3,5% e 5% do peso corporal para ratos diabéticos e não diabéticos, respectivamente. Depois da eutanásia, foram determinados corticosterona, insulina, glicose, peso da adrenal, concentração de colesterol da adrenal e glicogênio do músculo gastrocnêmio e conteúdo proteico total muscular também foram determinados. Foi aplicada análise de variância e Post Hoc de Tukey, com significância estatística menor que 5%. Peso da adrenal foi maior em SD (17.2±0.6g) que nos outros grupos (SC: 12.2 ±0.8g; TC: 13.7±0.6g; TD: 14.3±0.8g) e TD apresentou valores similares de TC. A corticosterona de SD foi maior do que SC e TC. Glicose sérica foi elevada no grupo diabético e a insulina foi menor neste grupo. Seis semanas de treinamento de natação foram eficientes para reduzir a concentração de marcadores de estresse em ratos diabéticos tipo 1. O treinamento de natação pode ser uma ferramenta útil para evitar a redução do conteúdo proteico muscular em ratos diabéticos tipo 1.