Schwann cells for spinal cord repair

Abstract

The complex nature of spinal cord injury appears to demand a multifactorial repair strategy. One of the components that will likely be included is an implant that will fill the area of lost nervous tissue and provide a growth substrate for injured axons. Here we will discuss the role of Schwann cells (SCs) in cell-based, surgical repair strategies of the injured adult spinal cord. We will review key studies that showed that intraspinal SC grafts limit injury-induced tissue loss and promote axonal regeneration and myelination, and that this response can be improved by adding neurotrophic factors or anti-inflammatory agents. These results will be compared with several other approaches to the repair of the spinal cord. A general concern with repair strategies is the limited functional recovery, which is in large part due to the failure of axons to grow across the scar tissue at the distal graft-spinal cord interface. Consequently, new synaptic connections with spinal neurons involved in motor function are not formed. We will highlight repair approaches that did result in growth across the scar and discuss the necessity for more studies involving larger, clinically relevant types of injuries, addressing this specific issue. Finally, this review will reflect on the prospect of SCs for repair strategies in the clinic.

Biodegradable Cell-Seeded Nanofiber Scaffolds for Neural Repair

“…The Need for Cell-Seeded Constructs Schwann cells alone have been unable to guide regenerating axons beyond a graft site to reenter the host spinal cord ("off-ramp") [195]. Thus, a combination strategy involving both engineered and cellular components may enhance regeneration across peripheral nerve gaps or SCI sites.…”

Functional properties of different collagen scaffolds to create a biomimetic niche for neurally committed human induced pluripotent stem cells (iPSC)

“…Human induced pluripotent stem cells (hiPSC) hold great promise for the future application in personalized medicine. Although many cell types have been transplanted into the injured spinal cord and brain tissue, including Schwann cells, olfactory ensheathing glia, activated macrophages, adult neural stem/progenitor cells and mesenchymal stem cells [19,22,41], induced pluripotent stem cells remain incompletely understood and should be further explored.…”

Functional recovery assessment of spinal cord contusion model in male rats without therapeutic interventions

“…Starting with the biological response, cytokines are secreted and inflammation is caused. Schwann cells with neutrophils, lymphocytes and macrophages travel to the site of the injury in a short time, and their anti-inflammatory and cytotoxic activity lead to injury development and create secondary injuries (8).…”

“…Damaged axons in the spinal cord have the ability of repair and regeneration to some extent. But the maximum growth of axons is about a millimeter and this recovery is not enough to have satisfactory functional outcome and recovery (8,9). Many factors are involved in partial repair and regeneration after SCI, including the lack of growth factors, inherent weak capacity of neurons in CNS for regeneration (12), chemical repellent molecules (13), inhibitors associated with proteoglycan glial scar such as chondroitin sulfate proteoglicans (CSPGs) or myelinassociated protein (MAP) (14).…”