Hyperhomocysteinemia and Cardiovascular Disease: Is the Adenosinergic System the Missing Link?

The influence of hyperhomocysteinemia (HHCy) on cardiovascular disease (CVD) remains unclear. HHCy is associated with inflammation and atherosclerosis, and it is an independent risk factor for CVD, stroke and myocardial infarction. However, homocysteine (HCy)-lowering therapy does not affect the inflammatory state of CVD patients, and it has little influence on cardiovascular risk. The HCy degradation product hydrogen sulfide (H(2)S) is a cardioprotector. Previous research proposed a positive role of H(2)S in the cardiovascular system, and we discuss some recent data suggesting that HHCy worsens CVD by increasing the production of H(2)S, which decreases the expression of adenosine A(2A) receptors on the surface of immune and cardiovascular cells to cause inflammation and ischemia, respectively.