Objective To determine the safety of the fetal olfactory ensheathing cell(OEC) transplantation in patients with chronic spinal cord injury (SCI) by examination of the magnetic resonance imaging (MRI). Methods A prospective clinical study involving 16 patients with chronic SCI was designed to investigate the feasibility and biological safety of the fetal OEC transplantation in treatment of SCI. The olfactory bulbs from the 3-4-month-old aborted human fetuses following the strict ethical guidelines were harvested and trypsinized down to single fetal OEC. These cells were then cultured for 12-17 days and were prepared for a clinical use. From November 2001 to December 2002, 16 patients with chronic SCI were randomly enrolled. The patients suffered from SCI for 1.5-8 years (average 4.3 years) after the injury. The suspension (50 μl) containing about 1×106 fetal OECs was transplanted by an injection into the patients' spinal cords above and below the injury site. All the patients were assessed before the transplantation and were followed up with MRI for 29-42 months (average 38 mon) after the transplantation. Results No cell-related adverse effects were observed in any patient during the follow-up period. The follow-up with MRI did not reveal any development of optic glial tumor, tumor-like mass, new hemorrhage, edema, expanding cyst, new cyst formation, infection or disruption of the neural structure in the transplant site of all the patients. Conclusion This is the first clinical study demonstrating the long-term safety of the OEC therapy for SCI. The results indicate that our protocol is feasible and safe in treatment of patients with chronic SCI within 38 months after the injury. Although the size of the samples for our study was not big enough, the positive results of the study have encouraged us to make a further research in this field.

BACKGROUND: It was thought that there was no regeneration capacityin central nerves. Recent research shows that regeneration capacity of injured neural axons and recovery of some neurological functions can be achieved by changing local surroundings after spinal cord injury (SCI).OBJECTIVE: To probe into whether the transplantation of fetal olfactory ensheathing cells (OECs) in recovering the neurological functions of patients with chronic SCI is safe, feasible, and effective.DESIGN: Auto-control observation before and after surgery.SETTING: Neurological Research and Treatment Center of Beijing Xishan Hospital; Second Department of Neurosurgery in Beijing Chaoyang Hospital Affiliated to Capital University of Medical Sciences; Second Department of Neurosurgery in Naval General Hospital.PARTICIPANTS: A total of 171 patients with chronic spinal cord injury were selected from the Second Department of Neurosurgery in Beijing Chaoyang Hospital Affiliated to Capital University of Medical Sciences and the Second Department of Neurosurgery in Naval General Hospital betweenNovember 2001 and February 2003, of which there are 147 patients with complete injury and 24 ones with incomplete injury. Post-injury period ranged from 0.5 to 18 years. Process of treatment is discussed and permitted by relevant Medical Ethics Committees. Cells were obtained from voluntary donors and patients agreed to receive the treatment.METHODS: ① Fetal olfactory bulbs were cultured for 12-17 days after being digested into single cells. ② Fetal OECs were transplanted into sites rostral and caudal to the epienter. ③ Neurological functions of all patients 2-8 weeks before and after operation were evaluated according to the scoring standard of ASIA.MAIN OUTCOME MEASURES: ① Status of functional recovery in spinal cord of patients after transplantation of OECs. ② Harmful events and side effects.RESULTS: A total of 171 patients were involved in the analysis of results.①Status of functional recovery in spinal cord of patients with OECs transplantation: Partial neurological functions of 171 patients rapidly recovered,whose motor function score increased from (34.5±20.3) points before operation to (42.0±20.0) points (P ＜ 0.001) after operation, score of light touch increased from (47.2±24.0) points to (61.8±23.0) points (P ＜ 0.001) after operation,score of pain sense increased from (48.6±23.5) points to (64.0±22.8) points (P ＜ 0.001). ②Harmful events and side-effects: Early manifestations of spinal cord injury induced by infection in surgical area of one patient aggravated; two patients suffered from serious pulmonary infection,one patient from thalamic hemorrhage. Three patients mentioned above died of serious respiration and circulatory failures.CONCLUSION: OEC transplantation can rapidly promote partial neurological function of patients with chronic SCI, while the mechanism needs further observing.