Transplantation Of Expanded Endothelial Colony Forming Cells Improved The Outcome Of Traumatic Brain Injury In A Mouse Model

BackgroundTraumatic brain injury is greatly harmful to human health, and it is one of the diseases with high mortality and disability rate of modern society, especially for middle-aged people younger than45-year-old. A series of complex post-traumatic pathophysiology cause microcirculation disturbance, increased permeability of the blood-brain barrier, neuronal death and neurological dysfunction. The study of traumatic brain injury was focused on the cerebral blood flow, metabolism, brain edema, intracranial hypertension, electrolyte balance, and brain tissue morphology changes. Although many research areas had made significant progress in the pathophysiological mechanisms after traumatic brain injury, the treatment of traumatic brain injury is still relatively limited, and based mainly on symptomatic and supportive treatment after the TBI. More and more investigators realize that the recovery of blood circulation of TBI area play a crucial role for the neurologic improvement. It has been tested that endothelial progenitor cells (EPCs) can increase the angiogenesis and promote the recovery of injury in many in vivo studies. Endothelial colony-forming cells (ECFCs) are homologous subtype of EPCs, with the stronger cellular proliferative potential and the more expression of vascular endothelial growth factor receptor. The transplantation of ECFCs for some diseases is a research hotspot currently.ObjectiveWe are in order to confirm that the endothelial progenitor cells in the circulating blood can homing and locate in the area of traumatic brain injury in a TBI mouse model in the acute phase of trauma, explore the transplanted blood endothelial progenitor cells cultured could improve nerve function in post-traumatic, and find a new therapeutic strategies for clinical treatment of TBI.MethodsThe way of gradient centrifugation was used to isolate the mononuclear cells (MNCs) from the fresh umbilical vein, and then the MNCs was cultured by the adherent culture method to get ECFCs colony, and proliferated in vitro. The cells obtained were detected by immunofluorescence to check the cell surface markers of ECFCs. Youth female nude mice received fluid percussion and were divided into3groups, the ECFCs treated group, the PBS treated group and without infusion group. A method of sex-mismatched was used to design the experiment. The cultured ECFCs from boys were infused by tail vein into female mice. The transplanted ECFCs’homing was detected by the way of fluorescence in situ hybridization (FISH) and used the Y chromosome-specific probes of human. Modified neurological severity score (Mnss) was used to evaluate the recovery of neurological function of TBI mice after transplantation, and the Morris water maze was used to evaluate the special learning memory deficit. The cytokines (VEGF and SDF1) expression of injured area was assessed by western blot, and the microvascular density (MVD) was used the way of immunohistochemistry. The relationship of angiogenesis and neurological functional recovery was analyzed at last.ResultsECFCs from donor were detected in the injured brain24hours after infusion. mNSS and MWM tests presented that the rate of neurological disability was significantly reduced in mice received ECFCs (P<0.05) and the ability of learning and memory improved greatly in the same group (P<0.05). Mice received with ECFCs had increased microvessel density (MVD), and the expression of cytokines including SDF1and VEGF in injured brain tissue.The increased microvascular density was negatively correlated with the mNSS.ConclusionThe ECFCs form cord blood could home to the injured brain area, and it could effectively increase the angiogenesis, promote the recovery of neurological function and improved long-term outcome after TBI. The findings suggest that ECFCs from human umbilical cord blood hold great potentials of cell therapy in patients after TBI.