Affiliations: Department of Physiology and Cell Biology, The Ohio
State University, Columbus, OH, USA | Neuroscience Graduate Studies Program,
The Ohio State University, Columbus, OH, USA | The Center for Brain and Spinal
Cord Repair, The Ohio State University, Columbus, OH, USA
Note: [] a
Abstract: Astrocytes comprise a heterogeneous cell population that plays a
complex role in repair after spinal cord injury. Reactive astrocytes are major
contributors to the glial scar that is a physical and chemical barrier to
axonal regeneration. Yet, consistent with a supportive role in development,
astrocytes secrete neurotrophic factors and protect neurons and glia spared by
the injury. In development and after injury, local cues are modulators of
astrocyte phenotype and function. When multipotent cells are transplanted into
the injured spinal cord, they differentiate into astrocytes and other glial
cells as opposed to neurons, which is commonly viewed as a challenge to be
overcome in developing stem cell technology. However, several examples show
that astrocytes provide support and guidance for axonal growth and aid in
improving functional recovery after spinal cord injury. Notably,
transplantation of astrocytes of a developmentally immature phenotype promotes
tissue sparing and axonal regeneration. Furthermore, interventions that enhance
endogenous astrocyte migration or reinvasion of the injury site result in
greater axonal growth. These studies demonstrate that astrocytes are dynamic,
diverse cells that have the capacity to promote axon growth after injury. The
ability of astrocytes to be supportive of recovery should be exploited in
devising regenerative strategies.
