The Role of Homocysteine in Diseases: A Review

Cardiovascular disease (CVD) is one of the most important causes of mortality worldwide. Several risk factors have been proposed to be associated with CVD. The main risk factors include family history, smoking, hypertension, history of diabetes, hyperlipidemia and obesity. However, new factors have been recently proposed to be associated with CVD. These include blood homocysteine, fibrinogen, plasma factor VII activity, lipoprotein (a) and several other factors. Nowadays, the role of homocysteine in the development and exacerbation of several diseases has been demonstrated. Extensive studies have been performed on the role of homocysteine in diabetes, preeclampsia, depression, Alzheimer's disease and multiple sclerosis. Homocysteine level increases with age. Moreover, absorption of micronutrients, especially vitamin B12, decreases in old age that could cause a further increase in homocysteine level. On the other hand, elasticity of blood vessels decline with aging, and increased levels of homocysteine accelerate atherosclerosis. The sum of these processes highlights the role of homocysteine in the development and exacerbation of several diseases.