Effects of Resistance Exercise on Slow-Twitch Soleus Muscle of Infarcted Rats.

Although current guidelines recommend resistance exercise in combination with aerobic training to increase muscle strength and prevent skeletal muscle loss during cardiac remodeling, its effects are not clear. In this study, we evaluated the effects of resistance training on cardiac remodeling and the soleus muscle in long-term myocardial infarction (MI) rats. METHODS: Three months after MI induction, male Wistar rats were assigned to Sham (n = 14), MI (n = 9), and resistance exercised MI (R-MI, n = 13) groups. The rats trained three times a week for 12 weeks on a climbing ladder. An echocardiogram was performed before and after training. Protein expression of the insulin-like growth factor (IGF)-1/protein kinase B (Akt)/rapamycin target complex (mTOR) pathway was analyzed by Western blot. RESULTS: Mortality rate was higher in MI than Sham; in the R-MI group, mortality rate was between that in MI and Sham and did not differ significantly from either group. Exercise increased maximal load capacity without changing cardiac structure and left ventricular function in infarcted rats. Infarction size did not differ between infarcted groups. Catalase activity was lower in MI than Sham and glutathione peroxidase lower in MI than Sham and R-MI. Protein expression of p70S6K was lower in MI than Sham and p-FoxO3 was lower in MI than Sham and R-MI. Energy metabolism did not differ between groups, except for higher phosphofrutokinase activity in R-MI than MI. CONCLUSION: Resistance exercise is safe and increases muscle strength regardless structural and functional cardiac changes in myocardial-infarcted rats. This exercise modality attenuates soleus glycolytic metabolism changes and improves the expression of proteins required for protein turnover and antioxidant response.

Influence of Isolated Resistance Exercise on Cardiac Remodeling, Myocardial Oxidative Stress, and Metabolism in Infarcted Rats.

INTRODUCTION: Exercise is an important therapeutic strategy for preventing and treating myocardial infarction (MI)-induced cardiac remodeling and heart failure. However, the myocardial effects of resistance exercise on infarcted hearts are not completely established. In this study, we investigated the effects of resistance exercise on structural, functional, and molecular cardiac alterations in infarcted rats. METHODS: Three months after MI induction or simulated surgery, Wistar rats were assigned into three groups: Sham (n = 14); MI (n = 9); and exercised MI (MI-Ex, n = 13). Exercised rats performed, 3 times a week for 12 weeks, four climbs on a ladder with progressive loads. Cardiac structure and left ventricle (LV) function were analyzed by echocardiogram. Myocyte diameters were evaluated in hematoxylin- and eosin-stained histological sections as the smallest distance between borders drawn across the nucleus. Myocardial energy metabolism, lipid hydroperoxide, malondialdehyde, protein carbonylation, and antioxidant enzyme activities were evaluated by spectrophotometry. Gene expressions of NADPH oxidase subunits were evaluated by RT-PCR. Statistical analyses were performed using ANOVA and Tukey or Kruskal-Wallis and Dunn's test. RESULTS: Mortality did not differ between the MI-Ex and MI groups. MI had dilated left atrium and LV, with LV systolic dysfunction. Exercise increased the maximum load-carrying capacity, with no changes in cardiac structure or LV function. Myocyte diameters were lower in MI than in Sham and MI-Ex. Lactate dehydrogenase and creatine kinase activity were lower in MI than in Sham. Citrate synthase and catalase activity were lower in MI and MI-Ex than in Sham. Lipid hydroperoxide concentration was lower in MI-Ex than in MI. Nox2 and p22phox gene expressions were higher in MI-Ex than in Sham. Gene expression of Nox4 was higher in MI and MI-Ex than in Sham, and p47phox was lower in MI than in Sham. CONCLUSION: Late resistance exercise was safe in infarcted rats. Resistance exercise improved maximum load-carrying capacity, reduced myocardial oxidative stress, and preserved myocardial metabolism, with no changes in cardiac structure or left ventricle function in infarcted rats.

Effects of the SGLT2 Inhibition on Cardiac Remodeling in Streptozotocin-Induced Diabetic Rats, a Model of Type 1 Diabetes Mellitus.

Clinical trials have shown that sodium glucose co-transporter 2 (SGLT2) inhibitors improve clinical outcomes in diabetes mellitus (DM) patients. As most studies were performed in Type 2 DM, the cardiovascular effects of SGLT2 inhibition still require clarification in Type 1 DM. We analyzed the effects of SGLT2 inhibitor dapagliflozin on cardiac remodeling in rats with streptozotocin-induced diabetes, an experimental model of Type 1 DM. Methods: Male Wistar rats were assigned into four groups: control (C, n = 14); control treated with dapagliflozin (C + DAPA, n = 14); diabetes (DM, n = 20); and diabetes treated with dapagliflozin (DM + DAPA, n = 20) for 8 weeks. Dapagliflozin dosage was 5 mg/kg/day. Statistical analyses: ANOVA and Tukey or Kruskal−Wallis and Dunn. Results: DM + DAPA presented decreased blood pressure and glycemia and increased body weight compared to DM (C 507 ± 52; C + DAPA 474 ± 50; DM 381 ± 52 *; DM + DAPA 430 ± 48 # g; * p < 0.05 vs. C; # p < 0.05 vs. C + DAPA and DM + DAPA). DM echocardiogram presented left ventricular and left atrium dilation with impaired systolic and diastolic function. Cardiac changes were attenuated by dapagliflozin. Myocardial hydroxyproline concentration and interstitial collagen fraction did not differ between groups. The expression of Type III collagen was lower in DM and DM + DAPA than their controls. Type I collagen expression and Type I-to-III collagen ratio were lower in DM + DAPA than C + DAPA. DM + DAPA had lower lipid hydroperoxide concentration (C 275 ± 42; C + DAPA 299 ± 50; DM 385 ± 54 *; DM + DAPA 304 ± 40 # nmol/g tissue; * p < 0.05 vs. C; # p < 0.05 vs. DM) and higher superoxide dismutase and glutathione peroxidase activity than DM. Advanced glycation end products did not differ between groups. Conclusion: Dapagliflozin is safe, increases body weight, decreases glycemia and oxidative stress, and attenuates cardiac remodeling in an experimental rat model of Type 1 diabetes mellitus.

Skeletal muscle aging: influence of oxidative stress and physical exercise.

Skeletal muscle abnormalities are responsible for significant disability in the elderly. Sarcopenia is the main alteration occurring during senescence and a key public health issue as it predicts frailty, poor quality of life, and mortality. Several factors such as reduced physical activity, hormonal changes, insulin resistance, genetic susceptibility, appetite loss, and nutritional deficiencies are involved in the physiopathology of muscle changes. Sarcopenia is characterized by structural, biochemical, molecular and functional muscle changes. An imbalance between anabolic and catabolic intracellular signaling pathways and an increase in oxidative stress both play important roles in muscle abnormalities. Currently, despite the discovery of new targets and development of new drugs, nonpharmacological therapies such as physical exercise and nutritional support are considered the basis for prevention and treatment of age-associated muscle abnormalities. There has been an increase in information on signaling pathways beneficially modulated by exercise; nonetheless, studies are needed to establish the best type, intensity, and frequency of exercise to prevent or treat age-induced skeletal muscle alterations.

Beneficial Effects of Physical Exercise on Functional Capacity and Skeletal Muscle Oxidative Stress in Rats with Aortic Stenosis-Induced Heart Failure.

Objective. We evaluated the influence of exercise on functional capacity, cardiac remodeling, and skeletal muscle oxidative stress, MAPK, and NF-κB pathway in rats with aortic stenosis- (AS-) induced heart failure (HF). Methods and Results. Eighteen weeks after AS induction, rats were assigned into sedentary control (C-Sed), exercised control (C-Ex), sedentary AS (AS-Sed), and exercised AS (AS-Ex) groups. Exercise was performed on treadmill for eight weeks. Statistical analyses were performed with Goodman and ANOVA or Mann-Whitney. HF features frequency and mortality did not differ between AS groups. Exercise improved functional capacity, assessed by maximal exercise test on treadmill, without changing echocardiographic parameters. Soleus cross-sectional areas did not differ between groups. Lipid hydroperoxide concentration was higher in AS-Sed than C-Sed and AS-Ex. Activity of antioxidant enzymes superoxide dismutase and glutathione peroxidase was changed in AS-Sed and restored in AS-Ex. NADPH oxidase activity and gene expression of its subunits did not differ between AS groups. Total ROS generation was lower in AS-Ex than C-Ex. Exercise modulated MAPK in AS-Ex and did not change NF-κB pathway proteins. Conclusion. Exercise improves functional capacity in rats with AS-induced HF regardless of echocardiographic parameter changes. In soleus, exercise reduces oxidative stress, preserves antioxidant enzyme activity, and modulates MAPK expression.

Reabilitação cardiovascular melhora capacidade funcional de pacientes cardiopatas após 3 anos de seguimento / Cardiovascular rehabilitation improves functional capacity of patients with heart disease after 3 years of follow up

Objetivo: Acompanhar os parâmetros cardiovasculares e funcionais de pacientes cardiopatas submetidos à reabilitação cardiovascular (fase 4) durante 3 anos. Materiais e Métodos: Trata-se de um estudo retrospectivo, no qual foram incluídos 11 pacientes submetidos a programa de reabilitação cardiovascular supervisionada por 3 anos. Os dados foram coletados de prontuários referentes às avaliações realizadas ao final do primeiro e do terceiro ano de reabilitação, realizada 2x/semana, sendo 60 minutos por sessão. Análise estatística: A normalidade dos dados foi testada pelo teste de Shapiro-Wilk. A comparação entre as variáveis paramétricas foi realizada pelo teste t-Student e, para as variáveis não paramétricas, foi aplicado teste de Mann-Whitney. O nível de significância adotado foi de 5%. Resultados: Hipertensão foi a patologia cardiovascular mais frequente no grupo estudado, presente em 11 pacientes (100%). Os pacientes foram considerados sobrepeso (25,89 ± 2,51 kg/m2 ). Foi observada melhora significativa da capacidade funcional (TC6M 1ª avaliação: 454,4 ± 110,4 m; 2ª avaliação: 588,0 ± 100,2 m, p=0,006). As demais variáveis não diferiram entre os dois momentos. Conclusão: O treinamento físico contínuo melhorou a capacidade funcional dos pacientes após 3 anos de seguimento de reabilitação cardiovascular.

Objective: To follow the cardiovascular and functional parameters of cardiac patients undergoing cardiac rehabilitation in phase 4, during 3 years. Methods: Retrospective study of 11 patients in cardiac rehabilitation program supervised during three years. Data were collected from medical records related to assessments performed at the end of the first and third year of rehabilitation. The rehabilitation program was performed twice a week, lasting 60 minutes per session. Statistical analysis was performed using the Shapiro-Wilk test to verify the normality of the data. For comparison of the parametric variables was performed the Student's t-test and, for the non-parametric variables, the MannWhitney test was applied. The level of significance was 5%. Results: The results showed hypertension as the most frequent cardiovascular disease in this group, in 11 patients (100%). Patients were considered overweight (25.89 ± 2.51 kg/m2 ). Regarding functional capacity, was observed a significant improvement (TC6M 1st evaluation: 454.4 ± 110.4 m; 2nd evaluation: 588.0 ± 100.2 m, p=0.006). The other variables did not differ between the two moments. Conclusion: The continuous physical training improved the functional capacity of patients after 3 years of follow-up of cardiovascular rehabilitation.

Treinamento físico em academia melhora qualidade de vida em pacientes no pós-operatório de revascularização miocárdica / Physical training in gym improves quality of life in postoperative myocardial revascularization patients

Introdução: A Reabilitação Cardiovascular usualmente é realizada em âmbito ambulatorial e hospitalar e pode ser expandido para academias. Objetivos: Avaliar a qualidade de vida de cardiopatas submetidos ao treinamento físico em curto prazo supervisionado por fisioterapeutas e educadores físicos em uma academia. Métodos: Foram avaliados 10 cardiopatas de ambos os sexos, média de faixa etária de 63.1±10,10 anos. Foram submetidos ao treinamento aeróbio em esteira ou bicicleta ergométrica, em intensidade moderada e um treinamento resistido em circuito em uma academia. O treinamento foi realizado por 45 dias, 2 vezes semanais, com duração de 1 hora. A aplicação do questionário de qualidade de vida SF-36 foi realizada antes e após o treinamento. Resultados: Com relação à força, houve melhora significante após a intervenção proposta. Foram constatadas melhoras em todos os aspectos da qualidade de vida. Conclusões: O treinamento físico realizado em academia melhorou a qualidade de vida de cardiopatas em curto período de reabilitação.

Introduction: Cardiovascular Rehabilitation is usually performed on an outpatient and hospital settings and can be expanded to gym. Aims: To assess the quality of life of cardiac patients undergoing short-term physical training, supervised by physical therapists and physical educator at a gym. Methods: We evaluated 10 cardiac patients of both sexes, average age 63.1 ± 10.10 years. They were submitted to aerobic training on a treadmill or stationary bike, at moderate intensity and resistance training circuit. The training was conducted for 45 days, 2 times weekly, 1 hour. The application of the SF-36 quality of life questionnaire was conducted before and after training. Results: In the strength data, there was significant improvement after the intervention proposal. improvements were noted in all aspects of quality of life. Conclusions: Physical training conducted in a gym improved the quality of life of cardiac patients in a short period of rehabilitation.