Resarchers have successfully transplanted olfactory cells to treat spinal cord injury in human trials.
Researchers from the Wenzhou Medical University state they have successfully repaired spinal cord injuries using the patients’ olfactory mucosa in human trials. Three years after they treated patients with spinal cord injury in a randomized clinical trial with transplanted cells from the patients’ olfactory mucosa (nasal cavities) the researchers state 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.’ The opensource study is published in the journal Cell Transplantation.
The current study used the patients’ olfactory mucosa to build a ‘bridge’ to span the gap between the damaged ends of the spinal cord. The data findings showed 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.
Previous studies show that autologous olfactory ensheathing cells (OECs) show high levels of nerve growth factor and neurotrophic receptor expression which is why they where chosen for the current study. The primary benefits of using OECs is that they are easy to isolate and avoid ethical issues. They have similar properties as Schwann cells and can survive in the peripheral nervous system.
The researchers 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 the current 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. The researchers state that most of the patients exhibited improvements within the first 12 to 24 months after surgery and their functional recovery slowly increased, but plateaued at 24 months after surgery.
Overall the results show a greater improvement in sensory function rather than motor function in the ASIA score assessment. The data findings also show 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 pre-operative evaluation.
The team note that optimal outcomes may be related to age, severity and level of injury, the quality and quantity of transplants, surgical technique, and post-operative rehabilitation. They go on to hypothesize that to derive clinical benefits from OEC transplants in combination with other pharmacological agents is most likely needed to achieve significant axon regeneration and re-establish functionally useful connections across the injured spinal cord.
The researchers surmise that another benefit of this study is that it was a randomized, controlled, double blind prospective study, unlike similar studies preceding it. They go on to add that although the current study demonstrated that OLP transplantation can lead to motor and sensory improvement, more work is needed to optimize this observed functional recovery.