Escherichia-Shigella expansion, reduced diversity distinguish T3cDM gut microbiome from T1DM

This study investigated gut microbiome alterations in pancreatogenic diabetes (type 3c diabetes, T3cDM) to determine if changes reflect systemic metabolic disturbances or primarily arise from exocrine pancreatic insufficiency (EPI). The research profiled the gut microbiome of 48 outpatients, including individuals with T3cDM, type 1 diabetes (T1DM), and healthy controls. Genus-level 16S rRNA data were analyzed using cross-validated LASSO logistic regression and patient-specific community metabolic models. Results showed T3cDM had reduced α-diversity and distinct β-diversity compared with both T1DM and healthy controls. Key compositional shifts in T3cDM included enrichment of the families Enterobacteriaceae (notably the genus Escherichia–Shigella) and Streptococcaceae. The LASSO logistic regression model identified specific bacterial genera as predictors, successfully discriminating T3cDM from T1DM with an area under the curve (AUC) of 0.867 and an accuracy of 0.818. The model highlighted Blautia, Escherichia–Shigella, Streptococcus, Clostridium, and Faecalibacterium as key predictors. Metabolic modeling indicated elevated growth of Escherichia–Shigella in T3cDM and revealed disease-specific metabolite fluxes. The study concludes that the observed gut microbial shifts in T3cDM predominantly reflect exocrine pancreatic insufficiency rather than the systemic metabolic disturbances characteristic of T1DM. This underscores the central role of exocrine pancreatic dysfunction in shaping the gut microbiome and its metabolic activity.

When diabetes is caused by a damaged pancreas, it's not just about insulin. A new study looked at the gut bacteria of people with this type of diabetes, called type 3c, and compared them to people with type 1 diabetes and healthy people. They found the gut's bacterial community in type 3c diabetes is less diverse and has a distinct makeup. Specifically, two families of bacteria—Escherichia-Shigella and Streptococcus—were more common. Using a statistical model, the researchers could tell the difference between type 3c and type 1 diabetes with good accuracy based on the levels of five key bacteria. Their analysis suggests these bacterial changes are primarily linked to the pancreas not producing enough digestive enzymes, a condition called exocrine pancreatic insufficiency. This means the gut microbiome shifts in this form of diabetes seem to be driven more by the direct effects of the damaged pancreas on digestion, rather than by the general metabolic disturbances of diabetes itself.