Hyper-homocysteinemia: a novel risk factor or a powerful marker for cardiovascular diseases? Pathogenetic and therapeutical uncertainties

Increased homocysteine levels can be responsible for arterial ischemic events, such as MI, stroke or peripheral vascular disease. Homocysteine is metabolized by two pathways: re-methylation and trans-sulfuration. Both involve folic acid, and vitamins B6-12. Several studies assumed that the folates and vitamins B supplementation or dietary source to normalize plasma homocysteine. But, even if tends to normalize homocysteine levels, lowering homocysteine by B-group vitamins and/or folates does not reduce cardiovascular risk. In fact, recent reports confirmed that hyper-homocysteinemia is not directly responsible for cardiovascular disease, but is merely present in individuals suffering for acute and/or chronic cardiovascular events, as a collateral finding. Reduced methylation potential (MP) [ due to decreased S-adenosyl-methionine (AdoMet)/S-adenosyl-homocysteine (AdoHcy) ratio] induced by the elevated plasma homocysteine levels seems to be the true responsible for cardiovascular diseases (CVD). The pathogenic mechanisms responsible for CVD appear to be dependent of DNA hypomethylation inducing an inhibition of cyclin A transcription and a reduction of endothelial cells growth. But, other human studies performed in a wide range are requested.