| Despite the significant progress that has been made in the management of ischemic disease, there remain a subpopulation of patients with peripheral or coronary artery disease who are not candidates for further direct revascularization. These patients always have diffusely diseased runoff vessels on angiography, a lack of available conduits, restenosis of angioplasty, occlusion of bypass and unacceptably high operative risk. These made them cannot be treated by surgical or percutaneous revascularization. They have recurrent symptoms that is refractory to maximal medical therapy. "Thrapertic angiogenesis" brings hope to the management of these patients.Angiogenesie and vasculogenesis comprise the mechanisms that responsible for the development of new blood vessels. Vasculogenesis is the process of in situ formation of blood vessels from endothelial progenitor cells (EPCs) or angioblast. Angiogenesis involves extension of the already formed primitive vasculature by the sprouting of new capillaries through migration and proliferation of previously differentiated ECs. Until recently, vasculogenesis was considered restricted to embryonic development, while angiogenesis, recognized to occur in the embryo as well, was considered to be solely responsible for postnatal neovascularization. The discovery of endothelial progenitor cells in the peripheral blood of adult revised this view. Not only angiogenesis but also vasculogenesis contribute to postnatal neovascularization.According to this, previous promoting neovascularization methodrestricted to the supplement of exogenous growth factors. But there was3age-related reduction in endothelial cell viability and endothelial dysfunction accompanies many known coronary risk factors that may reduce endothelial responsiveness to hypoxic stimuli or angiogenic growth factor. Strategies to increase the responsiveness of endothelial cells and increase the production of availability of endothelial progenitor cells are therefore reasonable targets for therapeutic angiogenesis.This study obtained endothelial progenitor cells from G-CSF mobilized peripheral blood hematopoietic stem cells of healthy donors by directed culture ex vivo. The adherent cells were considered EPCs. They have spindle shape and form blood-island-like structures during development. They also give rise to vessel-like cord structures. There are 8.825 + 2.958 adherent cells per 100 peripheral blood mononuclear cells. The adherent cells have many endothelial characteristics. They are von Willebrand Factor positive. They can endocytose Ac-LDL and bind to UEA-I. FACS disclosed that the binding rate of UEA-I was 92.1%. All of these results indicate that the adherent cells have obvious endothelial characteristics.We compared the number of GM-CSF before and after culture. GM-CFU which considered to represent the proliferate ability of hematopoietic cells was reduced after culture. This could be interpreted that the hemagioblast fate is diverted to endothelial cells when the hematopoietic differentiation is blocked. The phenotype of these cells also changed after culture. The phenotype of hematopoietic cells reduced while the endothelial markers like CD31, CD62E and KDR increased after culture.The second part of this study observed the effects of EPCs to athymic4nude mice with hindlimb ischemia. Fluorescent labeling and immunohistochemistry showed that the intravenously injected EPCs specifically distributed to the ischemic tissue. The perfusion of the ischemic limb in EPC group was better than control (p<0.01). The number of capillaries also increased compared with control (p<0.01). The animal experiment show that EPCs could targeted to the ischemic tissue, participate local vascuogenesis, increase the number of capillaries and improve the perfusion of ischemic hind limb.Our conclusion of this study was that EPCs could be obtained by directed culture from G-CSF mobilized human peripheral blood. These cells have many characteristics of endothelial cells. They targeted to...
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