Repair of injured spinal cord using biomaterial scaffolds and stem cells

Abstract

The loss of neurons and degeneration of axons after spinal cord injury result in the loss of sensory and motor functions. A bridging biomaterial construct that allows the axons to grow through has been investigated for the repair of injured spinal cord. Due to the hostility of the microenvironment in the lesion, multiple conditions need to be fulfilled to achieve improved functional recovery. A scaffold has been applied to bridge the gap of the lesion as contact guidance for axonal growth and to act as a vehicle to deliver stem cells in order to modify the microenvironment. Stem cells may improve functional recovery of the injured spinal cord by providing trophic support or directly replacing neurons and their support cells. Neural stem cells and mesenchymal stem cells have been seeded into biomaterial scaffolds and investigated for spinal cord regeneration. Both natural and synthetic biomaterials have increased stem cell survival in vivo by providing the cells with a controlled microenvironment in which cell growth and differentiation are facilitated. This optimal multi‒disciplinary approach of combining biomaterials, stem cells, and biomolecules offers a promising treatment for the injured spinal cord.

Figure 1

Neural conduits delivering stem cells enhance spinal cord axonal regeneration. (A) Neural conduits simultaneously provide structural guidance for axonal regeneration and act as carriers for stem cell transplantation. Stem cells differentiate into neurons (dark blue) and oligodendrocytes (light blue) that myelinate regenerated spinal cord axons (green). (B) Inhibition of axonal regeneration by glial scar after spinal cord injury.