VII.14. Homocysteine (Hcy)

Hcy is produced by the methionine metabolism. The normal range is <12.45 µmol/l. Its increased level is a risk marker for thrombosis and CVD. Its level may be increased by the genetic background (e.g. a lack of cystathionine – β-synthase – CBS, vitamin B₁₂ or folic acid), diseases (tumors, diabetes mellitus, renal failure, hyperthyroidism or hypertension) or medication (metformin).

Hcy decreases the life of the endothelial cells, and increases free radical production and lipid peroxidation. It decreases the production of endothelial NO and prostacyclin.  It increases thrombocyte aggregation and coagulation. It enhances the thickening of the arterial wall. It is not known whether its increased level is a cause or an effect in the MetS.