Neuronal repair and replacement in spinal cord injury.

Spinal cord injury (SCI) often induces loss of motor and/or sensory function below the level of injury. While deficits persist in complete lesions, partial lesions of the spinal cord can be followed by spontaneous functional recovery. In this review we address the mechanisms underlying spontaneous recovery in the adult CNS. We argue that the adult brain and spinal cord are able to spontaneously respond to SCI, and do so by (i) anatomically reorganizing axonal connections and (ii) generating new precursor cells. Knowledge of the endogenous recovery strategies should also provide the basis for the development of new therapeutic strategies for spinal cord injury. In this review we describe the processes of endogenous axonal repair and cell replacement in the injured spinal cord and discuss how transplantation of stem/progenitor cells could enhance these endogenous repair strategies.