SAT052 Prolonged Nursing Augments Short Chain Fatty Acid Levels And Leads To Amelioration Of Type 1 Diabetes

Disclosure: S. rafiqi: None. Z. Zahid: None. R. Lamendella: None. O. aghogho: None. E. Gionfriddo: None. Y. Tao: None. J.C. Jaume: None. S. Imam: None. The infant gut microbiome essentially shifts to a diverse and complex microbial system during weaning on separation from the mother and any perturbations lead to pathological imprinting with lifelong implications. Apart from breast milk, the microbiota of the skin and the intimate niche between mother and offspring contribute to gut microbial composition. Gut microbiome dysbiosis has been ascribed in the initiation and/or perpetuation of type 1 diabetes (T1D) in human and animal models. The gut microbial diversification is manifested as change in microbial metabolites particularly short-chain fatty acids (SCFAs) that have direct and indirect roles in immune regulation and epithelial barrier integrity. In this study, we try to decipher the role of prolonged nursing of newborn mice (upto 45 days) in the amelioration of type 1 diabetes in the context of changes in the gut microbiome and microbial metabolites. The humanized T1D mice used in the study spontaneously develop T1D at 3-4 weeks of age and are normally weaned at 21 days. Our results revealed mice subjected to prolonged nursing had consistent increments in levels of butyric acid from 60 to 150 days of age as compared to normal weaned mice, owing to a stable population of SCFA-producing bacteria developed during prolonged nursing with the mother. The normal weaned mice had a transient increase of butyric acid at 60 days but it didn’t sustain till the 150(th) day. The steady levels of butyrate in prolonged nursed mice exerted immunoregulatory roles which manifested in the enrichment of regulatory T cells (Tregs) in the intestinal mesenteric epithelium, payer’s patches, peri pancreatic lymph nodes (PLN), pancreas (PN) and spleen. The enrichment of Tregs leads to the regulation of diabetogenic Th1, Th17, and interferon gamma-producing CD8 T cells (cytotoxic lymphocytes, CTLs) at PLN, PN, and spleen. This increased immune tolerance was mirrored by improved glucose homeostasis and fasting blood glucose levels in the prolonged nursing group. Prolonged nursing preserved the pancreatic islet architecture and significantly maintained the increased number of islets per pancreas as observed in H&E sections. Also, it could be inferred from the results that SCFA’s promoted intestinal integrity with increased submucosal thickening, longer villi, and shallower crypts in the intestine of prolonged nursed mice. In conclusion, prolonged nursing accounts for gradual and steady gut microbiota succession in infants that augments SCFA production leading to enrichment of T regulatory cells and less aggressive diabetes. Presentation: Saturday, June 17, 2023