Incretin attenuates diabetes-induced damage in rat cardiac tissue

Metformin-mediated protection against Immunosenescence in diabetic cardiomyopathy: The potential roles of GDF-15 and klotho proteins

Diabetic cardiomyopathy (DCM) is a global health concern. However, studies examining the effect of metformin on diabetes-induced cardiac myocyte aging are lacking. This study aimed to investigate the protective effect of metformin against DCM involving modulation of macrophage phenotypes, growth differentiation factor-15 (GDF-15), and the anti-aging protein Klotho. Diabetes was induced in male Wistar rats using streptozotocin. Diabetic and nondiabetic rats were treated with metformin (200 mg/kg/day) and saline (control). DCM, inflammation, adhesion molecules, immunometabolic, and GDF-15 biomarkers were assessed using immunoassays. Western blotting was used to analyze Klotho expression. Macrophage phenotypes, senescence-associated-galactosidase (SA-β-gal), and p16INK4a were examined using immunohistochemistry, whereas the heart sections were histologically examined. The untreated diabetic rats showed increased serum troponin I and creatine kinase-MB levels, reflecting cardiac damage, which was confirmed via morphological changes and senescence. Klotho expression was decreased, indicating cardiac aging. Treatment with metformin reduced the heart weight-body weight ratio and lowered cardiac injury, inflammation, and adhesion molecule biomarker levels. It also reversed the histopathological changes induced by diabetes. It shifted macrophage polarization toward the M2 phenotype, decreased p16INK4a and SA-β-gal expression, and enhanced Klotho and GDF-15 expression. These findings revealed that diabetes induces cardiac aging by increasing senescence markers and decreasing the expression of Klotho. Metformin treatment protects against DCM by modulating macrophage phenotypes, attenuating immunosenescence-related dysregulation, and enhancing GDF-15 and Klotho expressions. Thus, metformin has potential clinical implications in alleviating DCM.

In vivo cardioprotective effect of zinc oxide nanoparticles against doxorubicin-induced myocardial infarction by enhancing the antioxidant system and nitric oxide production

BACKGROUND

Myocardial infarction (MI) is the result of reduced or stopped blood supply to a section of the myocardium. Regardless of its potential effectiveness in the treatment of several types of cancers, doxorubicin (DOX) capabilities are restricted because of its widespread cardiotoxic impact.

AIM

In this study, the protective effect of zinc oxide nanoparticles against doxorubicin-induced myocardial infarction in rats is examined.

METHODS

Zinc oxide nanoparticles (ZnO NPs) were synthesized and characterized using X-ray diffraction, transmission electron microscope, and UV-Vis spectral analysis. A total cumulative dose of DOX (18 mg/kg body weight, i.p.) was injected once daily on days 2, 4, 6, 8, 10, and 12 (i.p.) to induce MI in rats. 24 rats were divided into 4 groups; control, MI, and MI treated with two doses of ZnO NPs (45 and 22.5 mg/kg).

RESULTS

The treatment with ZnO NPs restored ST-segment near normal, ameliorated the changes in cardiac troponin T, creatine kinase, lactate dehydrogenase, aspartate aminotransferase, alanine amino transferase, alkaline phosphatase, total proteins, malondialdehyde, nitric oxide, reduced glutathione, and catalase.The histological investigation revealed that ZnO NPs treated group showed marked improvement in the examined cardiac muscle and liver in numerous sections.The lower dose of ZnO NPs (22.5 mg/kg) was significantly more effective than the higher dose (45 mg/kg).

CONCLUSION

The effect of ZnO NPs against doxorubicin-induced myocardial infarction in rats was assessed and the results revealed a successful cardioprotective potency through enhancing the antioxidant system and stimulating nitric oxide production in myocardial infarcted rats. This work implies that ZnO NPs could serve as promising agents for treating doxorubicin-induced cardiotoxicity.

Effects of platelet rich plasma on experimentally induced diabetic heart injury

Diabetic heart is one of the common complications of diabetes mellitus. Platelet-rich plasma (PRP) is an autologous product rich in growth factors that can enhance tissue regeneration. This work was conducted to study the PRP ability to improve diabetes-inducing cardiac changes. Also, it sheds more light on the possible mechanisms through which PRP induces its effects. Rats were divided into; control, PRP, diabetic, and PRP-diabetic groups. Cardiac specimens were obtained and processed for biochemical, histological, and immunohistochemical study. The diabetic group exhibited a significant increase in cardiac oxidative stress, inflammation, and cardiac injury markers if compared with the control group. Additionally, the cardiac tissue showed variable morphological changes in the form of focal distortion and loss of cardiac myocytes. Distorted mitochondria and heterochromatic nuclei were observed in the cardiac muscle fibers. The mean number of charcoal-stained macrophages, and mean area fraction for collagen fibers, mean number of PCNA-immune positive cardiac muscle were significantly decrease in PRP- diabetic group. Collectively, the results showed that PRP treatment ameliorated most of all these previous changes. CONCLUSION: PRP ameliorated the diabetic cardiac injury via inhibition of oxidative stress and inflammation. It was confirmed by biochemical, histological, and immunohistochemical study. It could be concluded that PRP could be used as a potential therapy for diabetic heart.

Irisin Attenuates Myocardial Ischemia/Reperfusion Injury and Improves Mitochondrial Function Through AMPK Pathway in Diabetic Mice

Aims

Several recent reports have shown irisin protects the heart against ischemia/reperfusion injury. However, the effect of irisin on I/R injury in diabetic mice has not been described. The present study was designed to investigate the role of irisin in myocardial ischemia-reperfusion (MI/R) injury in diabetic mice.

Methods

A mouse model of diabetes was established by feeding wild type or gene-manipulated adult male mice with a high-fat diet. All the mice received intraperitoneal injection of irisin or PBS. Thirty minutes after injection, mice were subjected to 30 min of myocardial ischemia followed by 3h (for cell apoptosis and protein determination), 24 h (for infarct size and cardiac function).

Results

Knock-out of gene FNDC5 augmented MI/R injury in diabetic mice, while irisin treatment attenuated MI/R injury, improved cardiac function, cellular ATP biogenetics, mitochondria potential, and impaired mitochondrion-related cell death. More severely impaired AMPK pathway was observed in diabetic FNDC5^-/- mice received MI/R. Knock-out of gene AMPK blocks the beneficial effects of irisin on MI/R injury, cardiac function, cellular ATP biogenetics, mitochondria potential, and mitochondrion-related cell death.

Conclusions

Our present study demonstrated that irisin improves the mitochondria function and attenuates MI/R injury in diabetic mice through AMPK pathway.

Does Glucagon-like Peptide-1 Ameliorate Oxidative Stress in Diabetes? Evidence Based on Experimental and Clinical Studies

Glucagon-like peptide-1 (GLP-1) has shown to influence the oxidative stress status in a number of in vitro, in vivo and clinical studies. Well-known effects of GLP-1 including better glycemic control, decreased food intake, increased insulin release and increased insulin sensitivity may indirectly contribute to this phenomenon, but glucose-independent effects on ROS level, production and antioxidant capacity have been suggested to also play a role. The potential 'antioxidant' activity of GLP-1 along with other proposed glucose-independent modes of action related to ameliorating redox imbalance remains a controversial topic but could hold a therapeutic potential against micro- and macrovascular diabetic complications. This review discusses the presently available knowledge from experimental and clinical studies on the effects of GLP-1 on oxidative stress in diabetes and diabetes-related complications.

Contribution of apoptosis in myocardial reperfusion injury and loss of cardioprotection in diabetes mellitus

Ischemic heart disease is one of the major causes of death worldwide. Ischemia is a condition in which blood flow of the myocardium declines, leading to cardiomyocyte death. However, reperfusion of ischemic regions decreases the rate of mortality, but it can also cause later complications. In a clinical setting, ischemic heart disease is always coincident with other co-morbidities such as diabetes. The risk of heart disease increases 2-3 times in diabetic patients. Apoptosis is considered to be one of the main pathophysiological mechanisms of myocardial ischemia-reperfusion injury. Diabetes can disrupt the anti-apoptotic intracellular signaling cascades involved in myocardial protection. Therefore, targeting these changes may be an effective cardioprotective approach in the diabetic myocardium against ischemia-reperfusion injury. In this article, we review the interaction of diabetes with the pathophysiology of myocardial ischemia-reperfusion injury, focusing on the contribution of apoptosis in this context, and then discuss the alterations of pro-apoptotic or anti-apoptotic pathways probably responsible for the loss of cardioprotection in diabetes.