Resveratrol primed adipose stem cell-derived exosomes alleviate intestinal ischemia reperfusion injury by regulating macrophage polarization.

Background: Intestinal ischemia/reperfusion injury (IRI) is a severe clinical condition associated with high morbidity and mortality. Despite advances in understanding the pathophysiology of IRI, effective therapeutic strategies remain limited. Adipose stem cell (ADSC)-derived exosomes (Exo) have been proven to be appropriate candidates for IRI through the anti-inflammatory effects. In this study, we investigated whether resveratrol (RSV)-primed ADSC-derived exosomes (RSV-primed Exo) could exert superior effects on alleviating intestinal IRI, and attempted to elucidate the underlying mechanism.

Methods: For the evaluation of the therapeutic effect of the RSV-primed Exo on intestinal IRI, in vitro and in vivo studies were performed. IRI model was established in male C57BL/6 mice by clamping the superior mesenteric artery for 45 min followed by reperfusion. Histopathological analysis, intestinal barrier, the proportion of T cells, and macrophage polarization were investigated. RSV-primed Exo mediated immunosuppressive activity was investigated by bone marrow-derived macrophages (BMDM) co-culture assay in vitro. Flow cytometry determined macrophage polarization. ELISA assays detected the function of macrophages. Furthermore, the role of the NF-κB pathway in RSV-primed Exo induced macrophage polarization was also elucidated.

Results: In vivo modeling in intestinal IRI showed that RSV pretreatment enhanced the therapeutic efficacy of ADSC-derived exosomes. Compared with Untreated and Exo-treated groups, RSV-primed Exo effectively attenuated pathological damage of intestine characterized by severe edema of the mucosal villi and the infiltration of inflammatory cells. Exo therapy conspicuously restored the downregulated expression of ZO-1, Occludin and Claudin-1 proteins in intestinal IRI mice and the administration of RSV-primed Exo further enhanced this restorative effect. Surprisingly, RSV-primed Exo significantly decreased the populations of M1 macrophages but increased the proportions of M2 macrophages in the intestine. Furthermore, RSV-primed Exo markedly reduced the levels of proinflammatory cytokines (IL-1β, IL-6, and TNF-α) and increased anti-inflammatory factor (IL-10) level in intestine. RSV-primed Exo improved macrophage immunoregulatory function associated with the NF-κB pathway, which exerted a potent therapeutic effect against intestinal IRI.

Conclusions: We demonstrated that RSV-primed Exo effectively suppress intestinal barrier dysfunctions and the dysregulation of mucosal immune responses. The results highlight that RSV-primed Exo could be novel and promising candidate for prevention of intestinal IRI.