Biochemistry & Analytical Biochemistry

Abstract

Homocysteine- The Hidden Factor and Cardiovascular Disease: Cause or Effect?

Pratima Tripathi

Markedly or mildly elevated circulating homocysteine concentrations are associated with increased risk of vascular occlusion. Here we review possible mechanisms that mediate these effects. Inborn errors of homocysteine metabolism result in markedly elevated plasma homocysteine (200-300 μmol/L) and thromboembolic (mainly venous) disease which is easily normalized with oral folate and ongoing trials are assessing the effect of folate treatment on outcomes. Some people have a common genetic variant (called methylenetetrahydrofolate reductase, abbreviated MTHFR) that also impairs their ability to process folate. Indeed, there are evidences suggesting an acute antioxidant effect of folic acid on homocysteine concentrations. This antioxidant mechanism may oppose an oxidant effect of homocysteine and be relevant to treatment of patients with vascular disease, especially those with chronic renal insufficiency. Such patients have moderately elevated plasma homocysteine and greatly increased cardiovascular risk that is largely unexplained.