The Role of mechanical stress in progression of intima hyperplasia associated to vein coronary bypass grafts disease

Coronary artery bypass grafting is a surgical procedure introduced to restore the blood circulation into the myocardium after an ischemic event. Despite progress in the use of arterial conduits, saphenous vein (SV) remains one of the most used vessels for the bypass. A short time after bypass implantation SV undergoes intima hyperplasia (IH) that progressively reduce its patency. One trigger cause of IH is the hemodynamic changes in the blood flow with higher sheer stress on the endothelial layer a radial deformation on the wall of the vein.The aim of this project was to understand the role of saphenous vein progenitors (SVP) in the progression of IH. These cells with high differentiation potential are the pericytes of vasa vasorum in the tunica adventitia. By in vitro and ex vivo models of mechanical stress we demonstrated the susceptibility of SVPs to the strain that causes a cytoskeletal reorganization and the acquisition of a potential migratory phenotype. SVPs showed the stimulus-related up-regulation of Amphoterin-Induced Gene And Open Reading Frame 2 (AMIGO2), that may have a role in the mechanical activation via prosurvival and migratory effects. For the first time has been described the presence of AMIGO2 in SVPs and its relationship with mechanical stress. Migratory phenotype acquisition and AMIGO2 overexpression demonstrate how SVPs are potential targets for further study of IH.