TRANSPLANT THERAPY - RECOVERY OF FUNCTION AFTER SPINAL-CORD INJURY

Spinal cord injuries (SCI) result in devastating loss of function and altered sensation. Presently, victims of SCI have few remedies for the loss of motor function and the altered sensation often experienced su bsequent to the injury. A goal in SCI research is to improve function in both acute and chronic injuries. Among the most successful interven tions is the utilization of transplanted tissues toward improved recov ery. The theory is that the transplanted tissue could (1) bridge the s pinal lesion and provide chemical and/or mechanical guidance for host neurons to grow across the lesion, (2) bridge the spinal lesion and pr ovide additional cellular elements to repair the damaged circuitry, (3 ) provide factors that would rescue neurons that would otherwise die a nd/or modulate neural circuits to improve function. A variety of tissu es and cells have been added to the adult mammalian spinal cord to enc ourage restoration of function. These include Schwann cells, motor neu rons, dorsal root ganglia, adrenal tissue, hybridomas, peripheral nerv es, and fetal spinal cord (FSC) tissue en bloc or as disassociated cel ls. It is postulated that these tissues would rescue or replace injure d adult neurons, which would then integrate or promote the regeneratio n of the spinal cord circuitry and restore function. In some instances , host-appropriate circuitry is supplied by the transplant and functio nal improvement is demonstrated. In this presentation, specific exampl es of recent work with transplanted tissue and cells that demonstrate improved behavioral outcome are presented. New recent work describing the in vitro propagation and characterization of human fetal spinal co rd multipotential progenitor cells are also described in the context o f a potential resource for transplantable cells. Additionally, data fr om transplantation experiments of human FSC cells into nonimmunosuppre ssed rat spinal cord are described, and the resultant improvements in behavioral outcome reported. Lastly, directions for future SCI researc h are proposed.