Gut Stem Cell Secretome Therapy Promotes Durable Neuroprotection and Functional Recovery After Stroke

Background: Stroke causes rapid neuronal death and gut barrier disruption in the acute phase, with persistent cognitive-affective impairment in the chronic phase. We previously showed that transplants of intestinal epithelial stem cells ameliorated the acute and chronic impairment of stroke. The current study tested the efficacy of a cell free strategy, specifically, the secretome of intestinal epithelial stem cells. Methods: Middle aged male and female rats underwent middle cerebral artery occlusion or sham surgery and received intestinal epithelial stem cell secretome from healthy sex-matched adult or control media. Behavioral assays (social interaction, novel object recognition and Barnes maze), gut histology, markers of gut permeability, serum cytokines were performed at acute and chronic time points. Group differences were assessed by two-way ANOVA. Results: In the acute phase, vehicle-treated stroke animals displayed histopathological changes in the gut including villus blunting, loss of goblet cells, increased markers of gut permeability and elevated systemic inflammation. In the chronic phase, stroke resulted in cognitive/affective changes including social withdrawal, recognition memory and spatial memory deficits. In middle-aged males, three doses of IESC secretome treatment 4h/24h/48h after stroke restored mucosal architecture, goblet cells and dampened inflammatory cytokines in the acute phase. Cognitive and social outcomes, tested 4+ weeks after stroke, were significantly improved compared to vehicle-treated stroke animals. However, in middle-aged females treated with the same regimen of intestinal epithelial stem cell secretome, gut architecture was not restored and inflammatory cytokines remained elevated. Long term cognitive impairment was only partially improved in this group. Proteomic analysis of the secretome revealed a largely shared core of proteins between males and females with sex differences in pathway level regulation. Subsequently, another cohort of middle-aged females was administered four doses of secretome 4h/12h/24h/36h after stroke. This regimen restored gut architecture and dampened inflammatory cytokines in the acute phase, and improved long term cognitive outcomes. Conclusions: Collectively, these studies underscore the therapeutic potential of IESC secretome and the importance of tailoring post stroke therapy by demographics such as biological sex. These data further support the hypothesis that gut repair is tightly associated with long-term improvement in stroke outcomes.