Chen et al observed high levels of hepatic matrix metalloproteinase-2, hepatic cytochrome 2E1, and significant liver fibrosis in long-term ethanol-feeding rats, which may be related to Hcy mediation, while combined treatment of folate and vitamin B12 can delay the progression of liver fibrosis by lowering serum Hcy levels.[36] As an important human nutrient and dietary supplement, Betaine plays an important role in maintaining adequate liver methionine supply and regulating Hcy concentration. The gene discussed is MMP2; the disease is Hepatic fibrosis.