CBS and hyperhomocysteinemia: At the same time, the reduced expression of CBS leads to a deficient biosynthesis of H2S. Which of hyperhomocysteinemia, impaired biosynthesis of H2S, or both is directly involved in the onset and progression of vascular diseases is not well established, but many studies support the use of compounds targeting the “H2S-system” in the treatment of hypertension [24,96], mainly due to the antihypertensive effects of the gasotransmitter [97] and its emerging role in the regulation of epigenetic mechanisms [98].