A therapeutic approach to treat cardiovascular dysfunction of diabetes

Abrogation of cardiomyopathy in diabetic rats by escin - possible role of NF-κβ and MCP-1

OBJECTIVE

Diabetic cardiomyopathy is one of the most common complications of diabetes. Escin may significantly inhibit myocardial damage through its NF-κβ inhibitory, antidiabetic, neuroprotective, and potent anti-inflammatory activity. Hence, the study was carried out to evaluate the effect of escin in diabetic cardiomyopathy.

METHODS

Diabetes induction was done in rats with streptozotocin. After six weeks of induction, diabetic animals were administered with escin (5, 10, and 20 mg/kg) for the next four weeks.

RESULTS

Escin prevented the progression of abnormalities in the biochemical, hemodynamic parameters and electrocardiogram. Escin also prevented the progression of abnormality in the oxidative stress parameters. The expression of NF-κβ and MCP-1 was significantly reduced with escin treatment. Furthermore, escin also prevented damage to myocardial cells and reduced collagen deposition in the cardiomyocytes.

CONCLUSION

Escin prevented the progression of cardiomyopathy in diabetic rats. Hence escin can be an alternative option for the management of diabetic cardiomyopathy.

Minocycline as heart conditioning agent in experimental type 2 diabetes mellitus - an antibacterial drug in heart protection

Cardiovascular diseases, and among them certainly myocardial infarction, remain leading cause of death worldwide. Diabetes increases risk of occurrence as well as adverse outcome of myocardial infarction. Conditioning maneuvers are the most attractive method for alleviating both the consequences of ischemia and reperfusion. Minocycline is a tetracycline derivative which exerts antioxidant, anti-inflammatory, and anti-apoptotic effects. The aim of this study was to assess the protective ability of preconditioning and postconditioning of isolated hearts from healthy and rats with experimentally induced type 2 diabetes with minocycline on functional recovery and redox status after ischemia and reperfusion. The hearts from healthy and diabetic rats were excised and retrogradely perfused according to the Langendorff technique. Using sensor in the left ventricle, the cardiodynamic parameters were recorded and in the samples of the coronary venous effluent oxidative stress biomarkers were analyzed. Minocycline was injected directly into the coronary vessels, in preconditioning 5 min before global ischemia, and in postconditioning during the first 5 min of reperfusion. Results of this study clearly show beneficial effects of minocycline applied both before ischemia and in the first minutes of reperfusion fashion in both healthy and diabetic rat hearts. The most prominent protective effect regarding oxidative stress is related to the decreased production of superoxide anion radical due postconditioning with minocycline in diabetic hearts. Cardiodynamic parameters were significantly improved in minocycline conditioned groups. Superoxide anion radical stands out as the most susceptible to changes induced by minocycline.

Daidzein mitigates myocardial injury in streptozotocin-induced diabetes in rats

AIM

Present study focuses on the effect of daidzein in an experimental model of diabetic cardiomyopathy in rats.

MATERIALS AND METHODS

Diabetes was induced in male Sprague Dawley rats by a single intraperitoneal injection of STZ at dose 55 mg/kg. Daidzein treatment was started after six weeks of diabetes induction. Animals received daidzein at a dose of 25, 50, and 100 mg/kg orally for the next four weeks.

KEY FINDINGS

Diabetic control animals showed significant prolongation in QT interval, PR interval, and R wave amplitude as compared to normal control animals. Treatment with daidzein at dose 100 mg/kg significantly normalized the QT interval, PR interval, and R wave amplitude. A significant reduction in QRS duration was observed in diabetic animals. Treatment with daidzein significantly improved the QRS duration after treatment. Hemodynamic parameters like systolic pressure (SBP), diastolic pressure (DBP) and mean atrial pressure (MAP) were found to be significantly decreased in diabetic animals. Treatment with daidzein at dose 100 mg/kg significantly improved the SBP, DBP, and MAP. Daidzein treatment prevented the loss of cardiac marker enzyme from heart tissue and also increased the level of AMPK and SIRT1 in plasma. Protein expression of NOX-4 and RAC-1 was also found to be reduced in cardiac tissue of daidzein treated animals. Daidzein treatment improved oxidative defense mechanism and reduced cardiac tissue necrosis and fibrosis.

SIGNIFICANCE

From the results, it can be concluded that daidzein mitigates the progression of diabetic cardiomyopathy by inhibiting NOX-4 induced oxidative stress in cardiac tissue.

The effect of folic acid administration on cardiac tissue matrix metalloproteinase activity and hepatorenal biomarkers in diabetic rats 1

Diabetes mellitus (DM) is a metabolic disorder that causes severe complications. Thus, the aims of this study were to investigate the influence of DM and folic acid treatment on liver and renal biomarkers, and heart remodeling through evaluation of cardiac matrix metalloproteinase (MMP) activity. There were 4 groups: control (physiological saline 1 mL/kg, i.p., 28 days), DM (streptozotocin [STZ] 100 mg/kg in physiological saline, i.p., 1 day), folic acid (FA; 5 mg/kg, i.p., 28 days), and DM+FA (STZ 100 mg/kg, i.p., 1 day and folic acid 5 mg/kg, i.p., 28 days). Our results demonstrated increased aminotransferase and alkaline phosphatase activity, urea and creatinine concentration, and decreased albumin and fibrinogen concentration in the DM group. MMP-2 relative activity was elevated in the DM and FA groups; MMP-9 was decreased in the DM and increased in the FA group. The folic acid treatment of diabetic rats did not change aminotransferase activity; it alleviated the increase in alkaline phosphatase and the decrease in albumin and fibrinogen concentration, and reduced MMP-2 activity; however, it increased urea and creatinine concentration. In conclusion, folic acid treatment of diabetic rats has cardio- and hepato-protective effects. However, its dosing should be carefully considered because of possible renal damage.

Efficacy of nobiletin, a citrus flavonoid, in the treatment of the cardiovascular dysfunction of diabetes in rats

Nobiletin, due to its MMP-2 & MMP-9 inhibitory and antioxidant effects, may ameliorate the cardiovascular dysfunction of diabetes.

Effects of nimesulide, a selective COX-2 inhibitor, on cardiovascular function in 2 rat models of diabetes

Cyclooxygenase-2 (COX-2) has been found to be activated in diabetes. We investigated whether nimesulide (selective COX-2 inhibitor) alters cardiovascular responses to adrenaline in 2 rat models of diabetes. Wistar rats (5-week old) were continuously fed a normal or high-fructose diet (60% of caloric intake). At week 2, half of the rats in each diet regimen were given streptozotocin (STZ) (60 mg/kg, intravenously). At week 6, cardiovascular effects of adrenaline (6 and 16 × 10 mol·kg·min, intravenously) were measured in 4 groups of thiobutabarbital-anesthetized rats (control, fructose, STZ, and fructose-streptozotocin [F-STZ]) before and after the injection of nimesulide (3 mg/kg, intravenously). Both the STZ and F-STZ groups exhibited hyperglycemia and significantly (P < 0.05) reduced left ventricular contractility, mean arterial pressure, arterial and venous resistance, and mean circulatory filling pressure (index of venous tone) responses to adrenaline, relative to the control and fructose groups. Nimesulide did not affect responses in the control and fructose groups but increased the venous and, to a less extent, arterial constriction to adrenaline in both the groups of diabetic rats. The cardiac contractile responses, however, were not altered after nimesulide treatment. The results show that nimesulide partially restored arterial and venous constriction to adrenaline in rats with STZ- and F-STZ-induced diabetes.

Enhancement of matrix metalloproteinase 2 and 9 inhibitory action of minocycline by aspirin: an approach to attenuate outcome of acute myocardial infarction in diabetes

BACKGROUND AND AIMS

Diabetes is a risk factor for exacerbated outcome after acute myocardial infarction (AMI) and doubles the risk of mortality after MI. Increased levels of MMP-2 and MMP-9 in diabetes cause vascular remodelling, which leads to cardiovascular complications of diabetes. We hypothesized that inhibition of MMP-2 and MMP-9 can reduce worsening of myocardial ischemia in diabetic patients. Further, we hypothesized that minocycline induced MMP-2 and MMP-9 inhibition will be potentiated by aspirin and the combination of both drugs will prevent worsening of MI in diabetic patients. In the present study, efficacy of combination of minocycline and aspirin to attenuate exacerbation of myocardial ischemia/reperfusion (I/R) injury in diabetic rats was evaluated.

METHODS

Diabetes was induced in male Wistar rats by streptozotocin (55 mg/kg i.p.). Three weeks after diabetes induction, rats were treated with minocycline (50 mg/kg, p.o.), aspirin (50 mg/kg, p.o.), or minocycline (50 mg/kg, p.o.) plus aspirin (50 mg/kg, p.o.) for a period of 3 weeks. At the end of week 6, I/R injury was induced by ligating the left anterior descending coronary artery for 30 min followed by 2 h reperfusion.

RESULTS

Percentage infarct volume, arrhythmias, mortality, collagen level and MMP-2 and MMP-9 level were significantly increased in vehicle-treated diabetic group when compared with normoglycemic rats. Treatment with a combination of minocycline and aspirin decreased percentage infarct volume, arrhythmias, mortality and collagen level when compared with vehicle-treated diabetic controls and showed reduced levels of MMP-2 and MMP-9.

CONCLUSIONS

Results of the present study suggest that the combination of minocycline and aspirin prevent worsening of AMI in diabetic rats.