Exogenous Heparin-Derivative Affords Protection Against Lipid Anomalies and Apoptotic DNA Damage in Experimental Atherogenesis

Abstract

Background: Cholesterol-induced cytotoxicity is a major cause of death of macrophages in atherosclerotic lesions. Apoptosis, or programmed cell death, plays an important role in atherogenesis. A deficiency of endogenous heparin activity is said to result in hypertriglyceridemia, hypercholesterolemia and enhanced atherogenesis, which is corrected on injecting exogenous heparin. In the current study, a low-molecular-weight heparin (LMWH), certoparin was tested for its influence on lipid anomalies and apoptotic damage in early atherogenesis. Methods and results: Two groups of male Wistar rats (140 ± 10 g) were fed an atherogenic diet comprising of normal rat chow supplemented with 4% cholesterol, 1% cholic acid and 0.5% thiouracil (CCT diet) for two weeks. One group was left untreated, the other was administered certoparin (300 μg/day/rat) commencing on day 8 and continued for a week. At the end of the two-week experimental period, we found significant elevation in plasma free cholesterol, free fatty acids and phospholipids (p < 0.001) and abnormal accumulation of cholesterol, triglycerides and phospholipids in the cardiac, hepatic and renal tissues of the untreated animals. Administration of LMWH subcutaneously corrected the lipid anomalies partly by restoring the altered activities of lipid metabolizing enzymes including total lipase, lipoprotein lipase, lecithin: cholesterol acyl transferase, cholesterol ester synthetase and hydrolase. Protein aggregation and cross- linking were observed in the cardiac microsomes of the untreated hypercholesterolemic group, along with significantly high malondialdehyde levels (p < 0.001); LMWH treatment afforded considerable protection against this oxidative damage. DNA fragmentation analysis and comet assay revealed marked DNA damage in the cardiovascular tissue from the untreated hypercholesterolemic group that was minimized by subcutaneous LMWH treatment. Conclusion: The LMWH, certoparin favorably modulates lipid disturbances in cardiac, hepatic and renal tissues, exerts a beneficial effect on oxidative changes and the structural integrity of cardiac microsomal membranes, and protects against apoptotic DNA damage in the cardiovascular tissue, thereby proving to be potentially anti-atherogenic.