Exercise training attenuates diabetes-induced cardiac injury through increasing miR-133a and improving pro-apoptosis/anti-apoptosis balance in ovariectomized rats

Exercise Training-Induced MicroRNA Alterations with Protective Effects in Cardiovascular Diseases

Exercise training (ET) is an important non-drug adjuvant therapy against many human diseases, including cardiovascular diseases. The appropriate ET intensity induces beneficial adaptions and improves physiological function and cardiopulmonary fitness. The mechanisms of exercise-induced cardioprotective effects are still not fully understood. However, mounting evidence suggest that microRNAs (miRNAs) play crucial role in this process and are essential in responding to exercise-stress and mediating exercise-protective effects. Thus, this review summarizes the biogenesis of miRNAs, the mechanism of miRNA action, and specifically the miRNAs involved in exercise-induced cardio-protection used as therapeutic targets for treating cardiovascular diseases.

Protective effects of swimming exercises and metformin on cardiac and aortic damage caused by a high-fat diet in obese rats with type 2 diabetes, by regulating the Bcl2/Bax signaling pathway

Background/aim

Due to the increasing mortality and morbidity rates in diabetes mellitus (DM), which is one of the biggest health problems of our age, many treatment modalities are still being tried. The positive effects of metformin (MET) and physical exercise (EXE) on the pathophysiology of diabetes are well known. In this study, it was aimed to detail these positive effects of MET and EXE in combination on the basis of inflammation, apoptosis mechanisms, and endogen nesfatin-1 (NES-1) synthesis.

Materials and methods

Twenty-seven type 2 DM (DM-2) male Wistar Albino rats were divided into 4 groups, as the high-fat diet (HFD), MET, EXE, and MET+EXE groups. The total duration of the study was 3 months. At the end of the experiment, blood glucose and lipid profiles were measured. Histopathological evaluation was performed on the cardiac and aortic tissues and apoptotic markers were evaluated immunohistochemically. Inflammatory markers and NES-1 levels were analyzed by enzyme-linked immunosorbent assay.

Results

The plasma glucose, homeostatic model evaluation-insulin resistance (HOMA-IR), low-density lipoprotein (LDL) levels increased, and high-density lipoprotein (HDL) levels decreased significantly in the HFD group. In the treatment groups, the glucose, HOMA-IR, LDL, NES-1 levels in the plasma, as well as tumor necrosis factor alpha (TNF-α), interleukin-1 beta (IL-1β), IL-6, caspase-3 (Cas-3), Bcl-2-associated X protein (Bax), and histopathological findings of inflammation in tissues were decreased. Additionally, there was an increase in plasma insulin, HDL, and tissue B-cell lymphoma-2 and levels.

Conclusion

It was observed that the MET and EXE treatments in the DM-2 model reduced cellular damage mechanisms such as inflammation and apoptosis. The decrease in NES-1 levels was thought to be secondary to this antiinflammatory effect. In conclusion, the results demonstrated the effectiveness of EXE in reducing DM-2 and the NES-1 levels. Further studies are needed to evaluate the effect in different EXE models and treatment durations.

Treatment with EV-miRNAs Alleviates Obesity-Associated Metabolic Dysfunction in Mice

Most cells release extracellular vesicles (EVs) that can be detected circulating in blood. We and others have shown that the microRNA contents of these vesicles induce transcriptomic changes in acceptor cells, contributing to the adjustment of metabolic homeostasis in response to environmental demands. Here, we explore the potential for modulating obesity- and exercise-derived EV-microRNAs to treat the metabolic dysfunction associated with obesity in mice. Treatment with EV-miRNAs alleviated glucose intolerance and insulin resistance in obese mice to an extent similar to that of high-intensity interval training, although only exercise improved cardiorespiratory fitness and decreased body weight. Mechanistically, EV-miRNAs decreased fatty acid and cholesterol biosynthesis pathways in the liver, reducing hepatic steatosis and increasing insulin sensitivity, resulting in decreased glycemia and triglyceridemia. Our data suggest that manipulation of EV-miRNAs may be a viable strategy to alleviate metabolic dysfunction in obese and diabetic patients who are unable to exercise, although actual physical activity is needed to improve cardiorespiratory fitness.

Research Progress on Epigenetics of Diabetic Cardiomyopathy in Type 2 Diabetes

Diabetic cardiomyopathy (DCM) is characterized by diastolic relaxation abnormalities in its initial stages and by clinical heart failure (HF) without dyslipidemia, hypertension, and coronary artery disease in its last stages. DCM contributes to the high mortality and morbidity rates observed in diabetic populations. Diabetes is a polygenic, heritable, and complex condition that is exacerbated by environmental factors. Recent studies have demonstrated that epigenetics directly or indirectly contribute to pathogenesis. While epigenetic mechanisms such as DNA methylation, histone modifications, and non-coding RNAs, have been recognized as key players in the pathogenesis of DCM, some of their impacts remain not well understood. Furthering our understanding of the roles played by epigenetics in DCM will provide novel avenues for DCM therapeutics and prevention strategies.

Diabetic neovascularization defects in the retina are improved by genistein supplementation in the ovariectomized rat

Genistein seems to have a protective and therapeutic effect on conditions associated with neovascular growth in the retina. This study investigated the angiogenesis, antioxidant, and anti-inflammatory effect of genistein on the retinas in ovariectomized diabetic rats. In this study, 40 female albino Wistar rats were divided into four groups (n = 8 per group): sham, ovariectomized group (OVX), OVX + diabetes (OVX.D), and OVX.D + genistein (OVX.D.G). OVX induced by removal of bilateral ovaries and then high-fat diet (HFD) and a low dose of streptozotocin (STZ) (1 mg/kg; intraperitoneal (IP) injection) was used for diabetes induction (OVX.D) with 8 weeks of genistein treatment (OVX.D.G). At the end of 8 weeks, the retina was removed under anesthesia. The samples were used to measure extracellular signal-regulated kinase (ERK), matrix metalloproteinase 2 (MMP-2), vascular endothelial growth factor (VEGF), and nuclear factor NF-kappa-B (NF-κB) by western blotting and inflammatory factors ELISA and oxidative stress. Measurements of glutathione (GSH) and malondialdehyde (MDA) showed that OVX and especially OVX.D significantly decreased GSH and increased MDA level in the retina, but genistein reversed these effects in OVX.D.G groups. Also, OVX and OVX.D significantly increased VEGF, MMP-2, p-ERK, NF-κB, interleukin-1beta (IL-1β), and tumor necrosis factor alpha (TNFα) expression in the retina of OVX and OVX.D groups in comparison to the sham group (p < 0.05). However, a significant reduction of these proteins was observed in the genistein-treated group (p < 0.05). In conclusion, bilateral ovariectomy and subsequently estrogen deficiency caused the development of inflammation, neovascularization, and then retinopathy in STZ-induced diabetic ovariectomized rats. On the basis of the results, genistein administration may be a practical approach for improving symptoms and complications of ovariectomized diabetic retinopathy.