Biological interventions for spinal cord injury.

Spinal cord injury is frequently followed by the loss of supraspinal control of sensory, autonomus and motor functions at sublesional level. To enhance recovery in patients with spinal cord injuries, three fundamental strategies have been developed in experimental models. These strategies involve three different time points for postlesional intervention in the spinal cord. Neuroprotection soon after injury uses pharmacological tools to reduce the progressive secondary injury processes that follow during the first week after the initial lesion occurs, in order to limit tissue damage. A second strategy, which is initiated shortly after the lesion occurs, aims at promoting axonal regeneration by acting pharmacologically on inhibitors or barriers of regeneration, or by the application of cell or gene therapy as a source of neurotrophic factors or as a bridge or support to enhance the regeneration of lesioned axons. Finally, a mid-term substitutive strategy is the management of the sublesional spinal cord by sensorimotor stimulation or the supply of missing key afferents, such as monoaminergic systems. These three strategies are reviewed. Only a combination of these different approaches can provide an optimal basis for potential therapeutic interventions aimed at functional recovery after spinal cord injury.