Ex vivo-expanded autologous bone marrow-derived mesenchymal stromal cells in human spinal cord injury/paraplegia: a pilot clinical study

Background aims Spinal cord injury (SCI) is a medically untreatable condition for which stem cells have created hope in the last few years. Earlier preclinical reports have shown that transplantation of bone marrow (BM) mesenchymal stromal cells (MSC) in SCI-simulated models can produce encouraging results. In a clinical pilot study, we investigated the growth kinetics of BM MSC from SCI patients, their safety and functional improvement post-transplantation. Methods Thirty patients with clinically complete SCI at cervical or thoracic levels were recruited and divided into two groups based on the duration of injury. Patients with < 6 months of post-SCI were recruited into group 1 and patients with > 6 months of post-SCI were included into group 2. Autologous BM was harvested from the iliac crest of SCI patients under local anesthesia and BM MSC were isolated and expanded ex vivo. BM MSC were tested for quality control, characterized for cell surface markers and transplanted back to the patient via lumbar puncture at a dose of 1 x 10(6) cells/kg body weight. Results At the time of writing, three patients had completed 3 years of follow-up post-BM MSC administration, 10 patients 2 years follow-up and 10 patients 1 year follow-up. Five patients have been lost to follow-up. None of the patients have reported any adverse events associated with BM MSC transplantation. Conclusions The results indicate that our protocol is safe with no serious adverse events following transplantation in SCI patients. The number of patients recruited and the uncontrolled nature of the trial do not permit demonstration of the effectiveness of the treatment involved. However, the results encourage further trials with higher doses and different routes of administration in order to demonstrate the recovery/efficacy if any, in SCI patients.