The enhancement of endothelial cell therapy for angiogenesis in hindlimb ischemia using hyaluronan

Growing evidence shows that injection of hyaluronan (HA) benefits ischemic injury in animals. On the other hand, cell therapy is an emerging approach to treat occlusive arterial diseases, although the low retention rate of cells after direct injection remains a major concern. Here, we tested whether injection of HA along with endothelial cells promotes the retention and growth of transplanted cells, thus improving therapeutic angiogenesis in a mouse model of hindlimb ischemia (HI). In culture, HA improved human umbilical vein endothelial cell (HUVEC) proliferation proportional to HA concentration and protected HUVECs from apoptosis. Subsequently, in immunocompromised mice HI was induced by femoral artery ligation and treatments were given 24 h later. At 4 weeks, injection of HA along with HUVECs had a greater effect for restoring blood perfusion and salvaging the ischemic limb compared to injection of HA or HUVECs alone. In addition, angiogenesis and arteriogenesis were significantly increased by HA + HUVECs injection. Lastly, HA + HUVECs injection resulted in the retention of more cells than HUVECs alone, and allowed their engraftment into the vasculature of the ischemic limb. These results suggest that this combined approach can be translated into a clinical therapy for peripheral artery occlusive disease.