Low intensity physical exercise attenuates cardiac remodeling and myocardial oxidative stress and dysfunction in diabetic rats

We evaluated the effects of a low intensity aerobic exercise protocol on cardiac remodeling and myocardial function in diabetic rats. Wistar rats were assigned into four groups: sedentary control (C-Sed), exercised control (C-Ex), sedentary diabetes (DM-Sed), and exercised diabetes (DM-Ex). Diabetes was induced by intraperitoneal injection of streptozotocin. Rats exercised for 9 weeks in treadmill at 11 m/min, 18 min/day. Myocardial function was evaluated in left ventricular (LV) papillary muscles and oxidative stress in LV tissue. Statistical analysis was given by ANOVA or Kruskal-Wallis. Echocardiogram showed diabetic groups with higher LV diastolic diameter-to-body weight ratio and lower posterior wall shortening velocity than controls. Left atrium diameter was lower in DM-Ex than DM-Sed (C-Sed: 5.73 ± 0.49; C-Ex: 5.67 ± 0.53; DM-Sed: 6.41 ± 0.54; DM-Ex: 5.81 ± 0.50 mm; P < 0.05 DM-Sed vs C-Sed and DM-Ex). Papillary muscle function was depressed in DM-Sed compared to C-Sed. Exercise attenuated this change in DM-Ex. Lipid hydroperoxide concentration was higher in DM-Sed than C-Sed and DM-Ex. Catalase and superoxide dismutase activities were lower in diabetics than controls and higher in DM-Ex than DM-Sed. Glutathione peroxidase activity was lower in DM-Sed than C-Sed and DM-Ex. Conclusion. Low intensity exercise attenuates left atrium dilation and myocardial oxidative stress and dysfunction in type 1 diabetic rats.

Metalloproteinases-2 and -9 predict left ventricular remodeling after myocardial infarction

Background: The role of serum metalloproteinases (MMP) after myocardial infarction (MI) is unknown. Objective: The aim of this study was to evaluate the role of serum MMP-2 and -9 as predictors of ventricular remodeling six months after anterior MI. Methods: We prospectively enrolled patients after their first anterior MI. MMP activity was assayed 12 to 72 hours after the MI. An echocardiogram was performed during the hospitalization and six months later. Results: We included 29 patients; 62% exhibited ventricular remodeling. The patients who exhibited remodeling had higher infarct size based on creatine phosphokinase (CPK) peak values (p = 0.037), higher prevalence of in-hospital congestive heart failure (p = 0.004), and decreased ejection fraction (EF) (p = 0.007). The patients with ventricular remodeling had significantly lower serum levels of inactive MMP-9 (p = 0.007) and significantly higher levels of the active form of MMP-2 (p = 0.011). In a multivariate logistic regression model, adjusted by age, CPK peak, EF and prevalence of heart failure, MMP-2 and -9 serum levels remained associated with remodeling (p = 0.033 and 0.044, respectively). Conclusion: Higher serum levels of inactive MMP-9 were associated with the preservation of left ventricular volumes, and higher serum levels of the active form of MMP-2 were a predictor of remodeling 6 months after MI. (Arq Bras Cardiol. 2013;100(4):315-321).