L-arginine supplement, the natural protection from cardiovascular disease: unraveling the biochemical mechanisms

ABSTRACT

To evaluate the anti-atherosclerotic effect of 'L-arginine and to unravel the biochemical mechanisms involved in this phenomenon. The effect of L-arginine is compared with nitroglycerin [NO donor] and enalapril [ACE inhibitor]. New Zealand white rabbits were rendered hypercholesterolemic by feeding 2% cholesterol rich diet for 28 days. Treated rabbits were given L-arginine [2.25 gm% in drinking water], nitroglycerin [175 mg orally on every day from day 15 to 27] or enalapril [3mg/kg orally] in conjunction with the 2% cholesterol enriched diet. The parameters measured were serum lipid profile, MDA, NO levels and Dimethylarginine dimethylaminohydrolase and ACE activities. Furthermore, aortic ACE activity and platelet aggregation were estimated. Histopathological examination and measurement of the intimal thickness of aorta were also performed. Although L-arginine, nitroglycerin and enalapril didn't significantly modify the lipid profile altered by hypercholesterolemia, they positively modified the parameters that were involved in atherogenesis. Reduction of serum MDA levels, serum ACE activities, platelet aggregation and aortic intimal thickness were achieved in all treated groups. L-arginine and nitroglycerin treatment were shown to increase serum NO levels. L-arginine and enalapril effectively inhibited aortic ACE activities. L-arginine supplementation exhibits anti-atherosclerotic properties very similar to those shown for the cardiovascular drugs, nitroglycerin and enalapril, thus its intake represents a potentially novel nutritional strategy for preventing cardiovascular diseases and their complications