Stem Cells for Spinal Cord Injury

Park et al. Glia. 2010 Jul;58(9):1118-32.

The use of mesenchymal stem cells for a variety have diseases has been published. This includes conditions such as heart failure, liver failure, stroke, and lupus. One of the attractive features of mesenchymal stem cells is that they can differentiate into numerous tissues while at the same time exerting anti-inflammatory activities.

In the situation of spinal cord injury, mesenchymal stem cells are thought to produce various growth factors that contribute to regeneration of the damaged nerve. In the paper by Park et al the question was asked whether Schwann Cells that are differentiated from mesenchymal stem cells may be a more potent source of therapeutic growth factors. This question was raised in part because the natural function of Schwann Cells is to produce factors that accelerate new neuron formation.

The researchers used a growth factor-based differentiation media to induce the transformation of mesenchymal stem cells into cells that resemble Schwann Cells. The resulting cells developed a morphology similar to Schwann Cells and expressed proteins that are specific to this cell type such as the p75 neurotrophin receptor.

It was found that the Schwann Cells generated from the mesenchymal stem cells expressed higher amounts of the growth factors hepatocyte growth factor (HGF) and vascular endothelial growth factor (VEGF) when compared with non transformed mesenchymal stem cells. When the newly generated cells were cultured with a neuronal cell line called Neuro2A, a large increase in the proliferation of the cell line was noted with a decrease in spontaneous cell death. Transplantation of the artificially generated Schwann Cells into an ex vivo model of spinal cord injury dramatically enhanced axonal outgrowth. This was blocked by antibodies to HGF and VEGF.

The authors propose that artificially generated Schwann Cells without genetic modification are useful for autologous cell therapy to treat nervous system injury.

One important question that was not addressed is to what extent are the Schwann Cells generated from mesenchymal stem cells seen by the immune system. In other words, is it possible to use Schwann Cells in a universal donor fashion the same way that mesenchymal stem cells can be used.