Mesenchymal Stem Cell Sheets Exert Antistenotic Effects in a Rat Arterial Injury Model

Restenosis after catheter or surgical intervention substantially affects the prognosis of arterial occlusive disease. Mesenchymal stem cells (MSCs) may have antistenotic effects on injured arteries. MSC transplantation from the adventitial side of an artery is safer than endovascular transplantation but has not been extensively examined. In this study, a rat model of femoral artery injury was used to compare the antistenotic effects of transplanted cell sheets and transplanted cell suspensions. Rat adipose-derived stem cells (ASCs) were used as the source of MSCs. For both cell sheets and suspensions, 6 × 10⁶ MSCs were transplanted on the day of arterial injury. MSC sheets attenuated neointimal hyperplasia more than MSC suspensions (intima-to-media ratio in hematoxylin/eosin-stained sections: 0.55 ± 0.13 vs. 1.14 ± 0.12; p < 0.05). Cell engraftment (assessed by immunohistochemistry or bioluminescence imaging of luciferase-expressing cells), arterial re-endothelialization (evaluated by immunohistochemical staining for rat endothelial cell antigen-1), and restriction of vascular smooth muscle cell proliferation in the neointima (double-staining of alpha-smooth muscle actin and phospho-histone H3) were greater when MSC sheets were applied than when MSC suspensions were used. In conclusion, MSC sheets exhibited better antistenotic and cell engraftment properties than MSC suspensions. MSC sheet transplantation from the adventitial side is a promising therapy for prevention of arterial restenosis.