People with type 1 diabetes appear to have latent inflammation of the digestive tract and disease-specific abnormalities in gut microbiota, according to study results published in the Journal of Clinical Endocrinology & Metabolism.1
“Our findings indicate the individuals with type 1 diabetes have an inflammatory signature and microbiome that differ from what we see in people who do not have diabetes or even in those with other autoimmune conditions such as celiac disease,” senior study author Lorenzo Piemonti, MD, from the Diabetes Research Institute at San Raffaele Hospital in Milan, Italy, said in a news release.2 “Some researchers have theorized that the gut may contribute to the development of type 1 diabetes, so it is important to understand how the disease affects the digestive system and microbiome.”
Dr Piemonti and colleagues evaluated biopsies of the duodenal mucosa of 19 patients with type 1 diabetes, 19 with celiac disease, and 16 healthy controls at San Raffaele Hospital between 2009 and 2015. Main outcomes included inflammation, as evaluated by gene expression study and immunohistochemistry, and microbiome composition, as analyzed by 16S rRNA gene sequencing.
When compared with patients with celiac disease and healthy controls, patients with type 1 diabetes demonstrated significantly more signs of inflammation in the duodenal mucosa linked to 10 specific genes: CCL13, CCL19, CCL22, CCR2, COX2, IL4R, CD68, PTX3, TNFα, and VEGFA.1 Type 1 diabetes-specific inflammatory status, which was primarily characterized by an increase in monocyte/macrophage lineage infiltration, was confirmed using immunohistochemical analysis.1
Additionally, patients with type 1 diabetes had a distinct combination of gut bacteria that differed from that of patients with celiac disease and healthy controls.1 Specifically, results showed that patients with type 1 diabetes had an increase in Firmicutes and ratio of Firmicutes to Bacteroidetes, as well as a decrease in Proteobacteria and Bacteroidetes.1
The researchers also found a relationship between the expression of genes specific for inflammation in type 1 diabetes and the abundance of specific bacteria in the duodenum.1
“We don’t know if type 1 diabetes’ signature effect on the gut is caused by or the result of the body’s own attacks on the pancreas,” Dr Piemonti said.2 “By exploring this, we may be able to find new ways to treat the disease by targeting the unique gastrointestinal characteristics of individuals with type 1 diabetes.”
- Pellegrini S, Sordi V, Bolla AM, et al. Duodenal mucosa of patients with type 1 diabetes shows distinctive inflammatory profile and microbiota [published online January 19, 2017]. J Clin Endocrinol Metab. doi: 10.1210/jc.2016-3222
- Type 1 diabetes linked to gut inflammation, bacteria changes [news release]. Washington, DC: Endocrine Society News Room; January 19, 2017. www.endocrine.org/news-room/current-press-releases/type-1-diabetes-linked-to-gut-inflammation-bacteria-changes. Accessed January 25, 2017.