CNN1 and atherosclerosis: During this phenotypic switch, the expression of multiple VSMCs-specific markers is decreased, such as α-smooth muscle actin (SMA), smooth muscle 22 α (SM22α), calponin 1 (CNN1), smooth muscle myosin heavy chain (SM-MHC) and transform to the synthetic phenotype, which contributes to neointima hyperplasia, atherosclerosis and aortic aneurysm (31).