Enhancement of gastrointestinal anastomosis healing via a small intestinal submucosa bio-patch: modulating IL-22 secretion by type 3 innate lymphoid cells and microbial structures.

PURPOSE: Anastomotic leakage and impaired healing remain major complications in gastrointestinal (GI) surgery. Small intestinal submucosa (SIS), a biological scaffold, has shown regenerative potential but its mechanisms in GI anastomotic healing remain unclear. This study aimed to investigate the effects of an SIS bio-patch on intestinal anastomotic healing, focusing on immune modulation, microbiota reshaping, and metabolic changes. METHODS: C57BL/6 mice underwent GI anastomosis with or without SIS bio-patch implantation. Five days post-operation, tissues were collected for histology, immunofluorescence, flow cytometry, 16S and ITS sequencing, and untargeted metabolomics. Immune cell composition, barrier protein expression, microbiota composition, and metabolic signatures were analyzed. RESULTS: SIS bio-patch significantly reduced inflammation and enhanced mucosal barrier integrity, as evidenced by reduced TNF-α and IL-6 and increased ZO-1 and occludin expression. SIS increased IL-22(+)ILC3s (type 3 innate lymphoid cells) and decreased the Th17/Treg ratio without altering macrophage polarization. Microbiota analysis showed increased abundance of Bifidobacterium and Alloprevotella, correlating positively with IL-22(+)ILC3s. Fungal sequencing revealed higher Fungi gen. Incertae sedis levels, associated with beneficial immune profiles. Metabolomics showed elevated amino acids and biotin metabolism in SIS-treated tissues, which may support epithelial regeneration. CONCLUSION: SIS bio-patch promotes anastomotic healing by enhancing IL-22(+)ILC3-mediated repair, rebalancing adaptive immunity, reshaping microbial communities, and upregulating pro-regenerative metabolic pathways. These findings support the use of SIS as an immunomodulatory biomaterial for gastrointestinal repair.