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.