gms | German Medical Science

Objectives: While no treatment strategies in Traumatic Brain Injury (TBI) are available, stem cells have emerged as putative therapeutic candidates. Endogenous stem cells can be activated following injury to provide local trophic support and exogenous stem cells can be transplanted to integrate with the host tissue. We present both functional and histological data in both stem cell transplantation and endogenous activation after TBI.

Methods: Adults rodents underwent a unilateral TBI. In the first experiments, we stereotactically injected human stem cells into the injury penumbra. In a separate study, following TBI, we modulated the Sonic Hedgehog signaling pathway to alter endogenous stem cell characteristics. In both experiments, brains were histologically assessed for cell type and cell maturation. Motor function and memory function were evaluated.

Results: In the cell transplantation experiments, transplant engraftment could be seen by 8 weeks. The transplant processes follow intact white matter tracts. Transplanted cells displayed a neuronal phenotype. Both motor performance and spatial memory were better compared to injured controls. In the endogenous cell experiments, endogenous stem cells were activated after injury, and were modulated following alteration of Sonic Hedgehog signaling. This was accompanied by improvements in motor performance compared to controls.

Conclusion: Stem cell therapy offers a potential treatment for TBI. Strategies to harness these cells include transplantation of cells into the injured site. Alternatively, there is the potential to harness the brain’s own endogenous stem cells for repair by modulating regulatory pathways. Both strategies result in improved functional performance post-injury.