Immunofluorescence (IF) staining of the mature SMC marker SMMHC and the SMC contractile marker αSMA demonstrated a significant decrease of SMC density in aortic vascular media and phenotypic switches in abdominal aortic aneurysm indicated by SMC morphology alteration (Figure 2C). This evidence concerns the gene ACTA1 and abdominal aortic aneurysm.