We developed mixed cell sheets consisting of fibroblasts and peripheral blood mononuclear cells that had high potency for secreting vascular endothelial growth factor. The purpose of this study was to confirm the therapeutic effects of mixed sheets in rabbits suffering from ulcers at the ischemic hind limbs. We used the ulcer model, which was constructed by implantation and sandwiching the skin between two magnets to be a representative of human refractory cutaneous ulcer. The ulcer healing rate of mixed cell sheets was higher than that of the control at an early stage of healing. The calf blood pressure and angiographic score, which were considered to reflect rough collateral blood flow, did not vary amongmixed cell sheets. However, through laser Doppler perfusion image, implantation of mixed cell sheets revealed a significant improvement in microvascular blood flow in the healed skin of the ischemic limb compared to trafermin, a recombinant human basic fibroblast growth factor, and the control. These results suggest that mixed cell may operate predominantly on the surface of the ischemic tissue by their angiogenic potency, thereby promoting healing of the ischemic ulcer. Mixed cell sheets could become a promising therapeutic material for refractory cutaneous ulcers.
Keywords: Cell sheet; angiogenesis; fibroblast; magnet; peripheral blood mononuclear cells; skin ulcer.