Homocysteine in uraemia--a puzzling and conflicting story

Abstract

Homocysteine (Hcy) is a non-protein sulfur-containing amino acid that consists of various forms: a protein-bound fraction (70–80%), a free oxidized form (20–30%) and a free reduced form (∼1%), which recently has attracted considerable interest as it may, by several mechanisms (Table 1) mediate premature atherosclerosis and cardiovascular disease (CVD). Indeed, in the general population, the results have shown that even mildly elevated plasma total homocysteine (tHcy) levels are associated with an increased cardiovascular risk [1–3]. However, not all prospective cohort studies are consistent with this finding [2] and, so far, the result of a large vitamin intervention study is not promising [4].