Our research group recently tested the in vitro effects of pioglitazone on MSCs obtained from human AAAs, observing that the PPAR-γ induction by drug administration correlated with a significant down-regulation of matrix metalloproteinase-9 (MMP-9) predominantly involved in pathological vascular remodeling during aneurysm and atherosclerosis pathogenesis [37]. This evidence concerns the gene MMP9 and achalasia-alacrima syndrome.