Abstract Body: Background: We showed that intestinal epithelial stem cells (IESCs) obtained from healthy young donor rats and transplanted to aging animals after stroke reduced infarct volume and sensorimotor impairment in the acute phase and mitigated cognitive impairment in the chronic phase. In most cases, stem cell transplants do not engraft or differentiate in vivo and their beneficial effects are proposed to occur through their secretions. Here we tested the hypothesis that IESC conditioned media (CM) would be similarly effective in improving acute and chronic stroke outcomes.
Methods: IESCs from young animals were cultured as organoids using our published protocol (PMID:36328163). Conditioned media was collected from these cultures and tested for treatment efficacy in middle-aged male and female rats assigned to the following groups: Control (sham), stroke+vehicle injection, or stroke+ IESC-CM treatment. Two treatment regimens were performed for IESC-CM treatments: 4h/24h/48h or 4h/12h/36h/48h after stroke. Stroke was induced by middle cerebral artery occlusion (MCAo) via Endothelin-1 (vasoconstrictor) followed by intraperitoneal injection (ip) of IESC-CM. Infarct volume and sensorimotor function were assessed on 4d post stroke and at 30 days post stroke, animals were tested on the Social Interaction test (depressive-like behavior) and, Novel object Recognition test and Barnes maze test respectively (cognitive assessment). Serum levels of the gut permeability markers and cytokines level were measured at both time points.
Results: IP treatment with IESC-CM significantly improved acute stroke outcomes and reduced gut permeability in middle-aged females. In chronic phase, vehicle-treated MCAo animals showed depressive-like behaviors compared to their pre-stroke behavior. In contrast, stroke animals that received IESCs-CM were no different from their pre stroke performance and were similar sham (no-stroke) animals. When assessing cognition, the MCAo+ vehicle animals showed poor discrimination abilities and impaired learning and retrieval memory. MCAo+IESCs-CM animals showed some improvement in episodic memory and spatial learning and retrieval with the 3 dose treatment, and significant improvement in both tests with the 4 dose treatment.
Conclusion: These data indicate that the secretome of IESCs is sufficient to promote stroke recovery and suggests a strategy to increase the translational potential of this therapy.