News & Events
Cell Transplants for Spinal Cord Injury: Clinical Trial Underway
Doctors at the The Miami Project to Cure Paralysis, part of the University of Miami Miller School of Medicine, have recently performed a Schwann cell transplant in a newly spinal cord-injured patient with a neurologically complete thoracic spinal injury. This procedure is part of a Phase 1 clinical trial that is the first of its kind and will eventually enroll eight patients. The study is designed to evaluate the safety and feasibility of transplanting a patient’s own cells into the spinal cord.
The Schwann cells, which typically create the myelin sheath around neurons, will be harvested from a sensory nerve in the leg. From this, the cells will be cultured for 3-5 weeks, allowing cells to proliferate and undergo a purification process. The cells will then be transplanted into the patient’s spinal cord. By applying the patient’s own cells to the injured spinal cord, doctors hope to avoid immune rejection of the cells.
Initial announcements report “no adverse events” in the first patient. Moving forward, doctors will assess patient recovery for the next five years, focusing on neurologic status, medical status, pain symptoms, and muscle spasticity.
The idea to use Schwann cells to encourage nerve regeneration in the spinal cord comes from the peripheral nervous system (PNS), where these cells actively participate in repair processes (Webber et al., 2011). Unfortunately, neuronal regeneration does not occur in the central nervous system (CNS). The extracellular environment of the CNS is not hospitable to nerve regeneration: glial cells here paradoxically produce proteins inhibitory to growth. Also, degeneration occurs more slowly in the CNS than the PNS, so cellular debris from the damage remains an obstacle for longer periods of time. Animal studies have shown another barrier to regeneration: the formation of a glial scar surrounding an injury site, preventing the progress of any potentially regenerating cells (Oudega and Xu, 2006)
This clinical trial is based in part on work from Dr. Mary Bartlett Bunge who proposed a “combination strategy” to improve the functional outcome of patients after spinal cord injury. In preclinical rat studies, she performed experiments that introduced Schwann cell “bridges” into injured spinal cords along with growth factors, which lead to improved neuronal survival (Meijs et al., 2004)
This is an exciting step on the road to a cure for spinal cord injury and we wish the researchers and patients all the best!
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Meijs MF, Timmers L, Pearse DD, Tresco PA, Bates ML, Joosten EA, Bunge MB, Oudega M. (2004). Basic fibroblast growth factor promotes neuronal survival but not behavioral recovery in the transected and Schwann cell implanted rat thoracic spinal cord. J Neurotrauma. Oct; 21 (10):1415-30.
Oudega M and Xu XM. (2006). Schwann cell transplantation for repair of the adult spinal cord. J Neurotrauma. Mar-Apr;23(3-4):453-67.
Webber CA, Christie KJ, Cheng C, Martinez JA, Singh B, Singh V, Thomas D, Zochodne DW. (2011). Schwann cells direct peripheral nerve regeneration through the Netrin-1 receptors, DCC and Unc5H2. Glia. Oct;59(10):1503-17.