Role of Angiogenesis as a Factor Modulating the Course of Cardiovascular Complications in Diabetic Rats
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- Category: Vol. 79, December 2011
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Role of Angiogenesis as a Factor Modulating the Course of Cardiovascular Complications in Diabetic Rats,AKEF KHOWEILED, HANY EL-SEBAEE, SAMAH EL-ATTAR and MOHAMED MANSOUR
Abstract
Background: Angiogenesis is an adaptive response that occurs in hypoxic and ischemic states as a compensatory mechanism and is modified by “on” switches as regular exercise and nitric oxide administration, and "off" switches as angiostatin. The normal healthy body maintains a perfect balance of angiogenesis modulators. Some authors believe that angiogenesis is beneficial for the myocardial performance during the course of Type II Diabetes mellitus; through providing more adequate blood supply to the cardiac myocyte. Others believe that angiogenesis may lead to micro-aneurismal formation with subsequent rupture and bleeding.
Aim of the Work: To study the effects of angiogenesis occurring as an adaptive response in diabetes mellitus, on cardiac functions and whether its stimulation by exercise or NO donor is beneficial or harmful on the cardiovascular performance and to study the effect of its inhibition on some cardiac function parameters.
Material and Methods: Fifty male white Albino rats were divided into 5 groups Group 1: (control group) normal rats fed on standard chow, Group 2: (diabetic group) diabetes was induced by fructose enriched chow, Group 3: (diabetic + angiostatin) angiostatin was given in a dose 5μg/kg each week for 4 weeks starting after 2 weeks from the start of the experiment, Group 4: (diabetic + exercise) exercise [1 hour of daily swimming divided into 4 periods of 15 minutes each, with a 5 minutes rest between each period] and Group 5: (diabetic + NO) L –Arginine was given at a dose 100mg/kg/day.
Results: The results showed a significant impairment in the cardiac performance in all the diabetic groups compared to the control group, and a significant increase in VEGF blood level and gene expression under the effect of exercise and nitric oxide supplementation, which was more marked under the effect of exercise, and a significant decrease in the VEGF blood level and gene expression under the effect angiostatin as compared to the control group. Correlation analysis revealed strong negative correlation between the insulin resistance and the cardiac performance parameters and positive correlation between the angiogenic markers [VEGF blood level and gene expression] and the cardiac performance parameters.
Conclusion: It can be concluded that stimulation of angiogenesis has a beneficial effects on the cardiovascular function in cases of DM, and that exercise exerts additional beneficial effect through improving insulin sensitivity.