Introduction: Stroke is the leading cause of long-term disability in the United States due to impairments that endure after brain injury. While studies in rodent models have evaluated numerous neurorestorative treatments following stroke, none have received FDA approval. We evaluated a therapy using human umbilical tissue-derived cells (hUTC) as a potential neurorestorative treatment in our non-human primate model of cortical injury limited to the hand area of primary motor cortex. Given treatment 24 hours after injury, hUTC treated monkeys showed a significantly greater degree of recovery of fine motor function compared to vehicle treated controls (Moore et al., 2013). To explore the effect of hUTC, histopathological markers of inflammation and oxidative stress were assessed.
Hypothesis: Treatment with hUTC will enhance the recruitment of glia to the injury and reduce the cascade of inflammation and oxidative stress.
Methods: Using immunohistochemistry, activated microglia (LN3), reactive astrocytes (GFAP), oxidative damage (4HNE), and accumulated hemosiderin (Perls’ Prussian Blue) were quantified in ipsilesional primary motor cortex and underlying white matter. Microglia were counted using unbiased stereology. A Sholl Analysis was performed on traced perilesional astrocytes. The area of oxidative damage and hemosiderin was assessed using densitometry.
Results: Compared to vehicle controls, density of activated microglia in the hUTC treated group approached a significant increase in the perilesional gray and white matter (p=0.070; p=0.092). Astrocytes exhibited more complex processes in treated monkeys (p=0.042). Staining for 4HNE was significantly reduced in white matter underlying the lesion in treated monkeys (p=0.033). Lastly, both the area and intensity of Perls’ staining for hemosiderin was significantly reduced in the perilesional area of treated monkeys (p=0.045; p=0.001).
Conclusions: Treatment with hUTC resulted in increased activation of microglia and complexity of reactive astrocyte processes as well as reduced post-lesion oxidative damage and hemosiderin deposition. This suggests the hUTC treatment enhanced recovery, in part, by recruitment of glial cells that limited the damage following cortical injury.