Three years after they treated patients with spinal cord injury in a randomized clinical trial with transplanted cells from the patients' olfactory mucosa to build a bridge to span the gap between the damaged ends of the spinal cord, scientists discovered that some recipients had experienced a range of modest improvements and determined that the use of olfactory mucosa lamina propria (OLP) transplants was “promising and safe.”
“This study demonstrated that transplantation of OLP affected motor functional recovery as well as improvement in ASIA sensory scores; bladder compliance, sensation, and partial control; and daily life activities,” wrote the investigators in an article (“Autologous Olfactory Lamina Propria Transplantation for Chronic Spinal Cord Injury: Three-Year Follow-up Outcomes From a Prospective Double Blinded Clinical Trial”) that will be published in a future issue of Cell Transplantation and is currently freely available online as an unedited early e-pub.
The researchers added that autologous olfactory ensheathing cells (OECs) are known to show high levels of nerve growth factor and neurotrophic receptor expression.
The team, based at Wenzhou Medical University in China, randomized 12 patients with complete spinal cord injury (SCI) to receive OLP transplants and followed them for three years after transplantation, noting that similar studies had not been designed to include long-term patient follow-up.
“The post-operative images in our study demonstrated that the transplants in the OLP group bridged the proximal and distal stumps (of the severed spinal cord), which may have provided assistance in establishing the integrity of the local neuronal signal circuit and conducting neural signals for early motor or sensory recovery,” said Hua-Zi Xu, M.D., department of spinal surgery, the second affiliated hospital of Wenzhou Medical University. 'Most of the patients exhibited improvements within the first 12 to 24 months after surgery, and their functional recovery slowly increased [before plateauing] at 24 months after surgery.”
Overall, wrote the researchers, there appeared to be a “greater improvement in sensory function rather than motor function in the ASIA score assessment.” They noted normalized bladder function in one patient and the return of bladder sensation in two of eight patients at 24 months. Eight of the 12 patients were without bladder sensation at the preoperative evaluation.
“Optimal outcomes may be related to age, severity and level of injury, the quality and quantity of transplants, surgical technique, and postoperative rehabilitation,” continued the researchers. “We believe that to derive clinical benefits from OEC transplants a combination with other pharmacological agents is most likely to achieve significant axon regeneration and re-establish functionally useful connections across the injured spinal cord.”