MMP1 and atherosclerosis: Some studies have reported that serum homocysteine can promote the production of oxygen free radicals in the body, damage vascular endothelial cells and vascular function, and further cause intimal thickening and stiffness of blood vessels, leading to atherosclerosis.[18]Raaf[19] and others have found that HHcy can increase the level of transforming growth factor-β1 (TGFβ1), affect the balance between TIMP1 and MMP1, lead to dysregulation of extracellular matrix degradation, cause extracellular matrix remodeling, and affect cardiac function.