[Therapeutic angiogenesis by autologous cell implantation].

Therapeutic angiogenesis is an effective means for tissue salvage in patients with critical limb ischemia. Angiogenesis is defined as a formation of new blood vessels by sprouting of preexisting mature endothelial cells(ECs). In contrast, vasculogenesis is referred to as the creation of primordial blood vessels from endothelial progenitor cells (EPCs) or angioblasts. Neovascular formation in adults has been considered to result exclusively from the former process(i.e., angiogenesis). However, we and other researchers recently identified EPCs in human peripheral blood(PB), and circulating EPCs have been shown to accumulate at active angiogenic sites and to participate in neovascularization, a notion consistent with 'postnatal vasculogenesis'. EPCs in adults originate from bone marrow(BM), and we recently have demonstrated that in vivo implantation of autologous BM-MNCs effectively augmented ischemia--induced neovascularization in animal studies as well as human trial(TACT Trial). Here we summarize recent advances in cell transplantation-mediated therapeutic angiogenesis.