Catechin combined with vitamins C and E ameliorates insulin resistance (IR) and atherosclerotic changes in aged rats with chronic renal failure (CRF)

Aging is an inevitable biological process associated with increased oxidative stress and accumulation of asymmetric dimethylarginine (ADMA) a known endogenous inhibitor of nitric oxide synthase. Atherosclerosis and IR constitute major risk factors for cardiovascular mortality in elderly with chronic kidney disease (CKD). We investigated the impact of catechin, vitamins E and C supplementation on insulin sensitivity, redox state, ADMA, nitrate and nitrite (NO2−/NO3−) levels and histological picture of heart and large blood vessels of aged rats with CRF. Findings of the present study revealed that aging in rats is associated with hyperinsulinemia, hyperlipidemia, IR indicated by higher homeostasis model assessment (HOMA)-index, increased lipid peroxidation product malondialdehyde (MDA), ADMA, and blood pressure (BP), but decreased antioxidant capacity and NO2−/NO3− levels. CRF exaggerated all these findings and caused thickened intima of carotid arteries and myocardial hypertrophy. Treatment with catechin, vitamins E and C increases the antioxidant capacity and NO2−/NO3− production but, decreases MDA, ADMA and BP levels. Also it keeps insulin sensitivity and normal intima/media thickness of carotid arteries. We conclude that decreased nitric oxide (NO) availability due to ADMA accumulation may be responsible for IR and associated atherosclerotic changes in aged rats with CRF. Catechin, vitamins E and C supplementation may moderate oxidative stress of renal failure, prevent ADMA accumulation, and counteract IR and atherosclerotic changes in the elderly.