Modulation of the gastrointestinal microbiota normalizes the systemic inflammation and islet immunocyte recruitment capacity associated with autoimmune diabetes (in Biobreeding rats) [RatIslet_Longitudinal]

Sequencing of the bacterial 16S rRNA gene revealed that these treatments significantly altered the ileal and cecal microbiota, resulting in increases in the Firmicutes:Bacteriodetes ratio, and abundances of lactobacilli and butyrate producing genera. Both treatments partially normalized the peripheral inflammatory state, reducing plasma cytokine, chemokine and TLR-4 activity levels. The proinflammatory islet transcriptome was more extensively normalized by HCD and immune-fluorescent staining revealed reductions in β-cell chemokine expression. HCD and antibiotic treatment did not normalize BB rat PBMC hyper-responsiveness to ex vivo mitogen stimulation. Combined, these studies link islet-level T1D susceptibility in BB rats to a genetically controlled innate inflammatory state that is influenced by environmental determinants encompassing the diet and the intestinal microbiota.