Circulating progenitor cells

The existence of circulating cells, endothelial progenitor cells (EPC), in peripheral blood was first demonstrated in 1997. Under pathological conditions EPCs are mobilized from the bone marrow. A variety of factors which stimulate mobilization were identified, including granulocyte colony stimulating factor, vascular endothelial growth factor (VEGF) and interleukin 8. Endothelial progenitor cells participate in remodelling processes of the vascular walls by clustering in areas of endothelial damage and reducing the formation and hyperplasia of neointima and atherosclerotic plaques. This discovery allowed new approaches in the treatment of peripheral arterial occlusive disease. In most studies an improvement in perfusion of tissues and a reduction of the amputation rate have been observed following transplantation of EPCs but the results did not live up to expectations. With respect to clinical benefits the supportive application for vascular interventions, in addition to the development and colonization of suitable synthetic prosthetic materials and the benefits for tissue engineering look very promising.