Endothelial Progenitor Cells : implications for radiation-induced brain injury

抄録

Radiation therapy, the most commonly used for the treatment of brain tumors, has been shown to be of major significance in tumor control and survival rate of brain tumor patients. About 200,000 patients with brain tumor are treated with either partial large field or whole brain radiation every year in China. The use of radiation therapy for treatment of brain tumors, however, may lead to devastating functional deficits in brain several months to years after treatment. An initial brain pathology resulting from exposure to radiation appears to be the dysfunction or disruption of the blood-brain barrier (BBB) and edema formation, which resulted from loss of tight junction (TJ) proteins and BBB components pericytes and astrocyte end-feet. Both of these scenarios lead to apoptosis of endothelial and neural cells and neuroinflammation in and around capillaries, which may progress into a variety of neurological impairments. It's been found that Bone-marrow-derived EPCs (endothelial progenitor cells) play an integral role in the regulation and protection of the endothelium, as well as new vessel formation. It can incorporate into injured vessels and become mature endothelial cells during re-endothelialization and neovascularization processes, so the transplantation of EPCs into ischemic tissues provide a novel therapeutic option for radiation-induced brain injury. The efficacy of EPCs repairing disrupted BBB can be evaluated from the changes of expression of S100B, VEGF and EBA. MRI is a non-invasive method that can be used to track labeled transplanted cells,which can show the exact trace of EPCs in the region of brain injury. This review discusses the therapeutic potential of EPCs for vascular ischemic diseases associated with radiation-induced brain injury.