Chronic spinal injury repair by olfactory bulb ensheathing glia and feasibility for autologous therapy.

Olfactory bulb ensheathing glia (OB-OEG) promote repair of spinal cord injury (SCI) in rats after transplantation at acute or subacute (up to 45 days) stages. The most relevant clinical scenario in humans, however, is chronic SCI, in which no more major cellular or molecular changes occur at the injury site; this occurs after the third month in rodents. Whether adult OB-OEG grafts promote repair of severe chronic SCI has not been previously addressed. Rats with complete SCI that were transplanted with OB-OEG 4 months after injury exhibited progressive improvement in motor function and axonal regeneration from different brainstem nuclei across and beyond the SCI site. A positive correlation between motor outcome and axonal regeneration suggested a role for brainstem neurons in the recovery. Functional and histological outcomes did not differ after transplantation at subacute or chronic stages. Thus, autologous transplantation is a feasible approach as there is a time frame for patient stabilization and OEG preparation; moreover, the healing effects of OB-OEG on established injuries may offer new therapeutic opportunities for chronic SCI patients.