Conditional expression of the type 2 angiotensin II receptor in mesenchymal stem cells inhibits neointimal formation after arterial injury

Exosomes Derived from AT2R-Overexpressing BMSC Prevent Restenosis After Carotid Artery Injury by Attenuating the Injury-Induced Neointimal Hyperplasia

Restenosis is a severe complication after percutaneous transluminal coronary angioplasty which limits the long-term efficacy of the intervention. In this study, we investigated the efficiency of exosomes derived from AT2R-overexpressing bone mesenchymal stem cells on the prevention of restenosis after carotid artery injury. Our data showed that AT2R-EXO promoted the proliferation and migration of vascular endothelial cells and maintained the ratio of eNOS/iNOS. On the contrary, AT2R-EXO inhibited the proliferation and migration of vascular smooth muscle cells. In vivo study proved that AT2R-Exo were more effectively accumulated in the injured carotid artery than EXO and Vehicle-EXO controls. AT2R-EXO treatment could improve blood flow of the injured carotid artery site more effectively. Further analysis revealed that AT2REXO prevents restenosis after carotid artery injury by attenuating the injury-induced neointimal hyperplasia. Our study provides a novel and more efficient exosome for the treatment of restenosis diseases after intervention.

Endothelial‑like cells differentiated from mesenchymal stem cells attenuate neointimal hyperplasia after vascular injury

The present study investigated the contribution of bone marrow-derived mesenchymal stem cells (BM-MSCs) to neointimal formation, and whether endothelial-like cells (ELCs) differentiated from BM-MSCs could attenuate intimal hyperplasia following vascular injury. BM-MSCs were isolated from rat femurs and tibias and expanded ex vivo. Differentiation into ELCs was induced by cultivation in the presence of 50 ng/ml vascular endothelial growth factor (VEGF). MSCs and ELCs were labeled with BrdU and injected via the femoral vein on the day of a balloon-induced carotid artery injury. Carotid artery morphology and histology were examined using ultrasound biomicroscopy and immunohistochemistry. Flow cytometry analysis measured CD31 and CD34 expression, and immunofluorescence analysis measured von Willebrand factor and VEGF receptor 2 expression in ELCs. Ultrasound biomicroscopy observed a significantly increased intima-media thickness in the phosphate-buffered saline (PBS) and BM-MSCs groups compared with the ELCs group. Intima/media ratios were significantly reduced in the ELCs group compared with the PBS and BM-MSCs groups. At 4 weeks of administration, the cells labeled with BrdU were abundantly located in the adventitial region and neointima. MSCs were able to differentiate into ELCs in vitro. Cell therapy with BM-MSCs was not able to attenuate neointima thickness, however transplantation with ELCs significantly suppressed intimal hyperplasia following vascular injury.