While a large waistline and high blood sugar levels are known risk factors for diabetes, researchers have now found that having bacteria that penetrate the mucus lining of the colon may promote metabolic disease, particularly Type-2 diabetes. Metabolic syndrome, which has become far more common due to a rise in obesity rates among adults, is a leading risk factor for many serious, life-threatening diseases, including Type-2 diabetes and heart disease, according to the US National Institutes of Health. “Alterations in bacteria have been associated with metabolic diseases, including obesity and Type-2 diabetes, but mechanisms remain elusive,” said one of the lead researchers Andrew Gewirtz, Professor at Georgia State University in the US.
“Previous studies in mice have indicated that bacteria that are able to encroach upon the epithelium might be able to promote inflammation that drives metabolic diseases, and now we’ve shown that this is also a feature of metabolic disease in humans, specifically Type-2 diabetics who are exhibiting microbiota encroachment,” Gewirtz added.
The epithelium is the mucus-lined cellular covering of internal and external surfaces of the body, including the intestinal tract. The findings, published in the journal Cellular and Molecular Gastroenterology and Hepatology, may help open a new field of investigation in metabolic function and Type-2 diabetes.
Gut microbiota is the collective term for the communities of microscopic living organisms that inhabit this environment. Gut microbiota that live in the outer regions of the mucus and remain a safe distance from epithelial cells provide a benefit to the host, but the researchers hypothesised that microbiota that encroach upon host cells drive chronic inflammation that interferes with the normal action of insulin, promoting Type-2 diabetes.
In this study, the researchers used samples from human participants enrolled at the Veteran’s Administration Hospital in Atlanta. The participants, at least 21 years old with no major health problems besides diabetes, were undergoing colonoscopy for colon cancer screening. The researchers obtained each participant’s history of diabetes and gastrointestinal complaints through interviews and reviewing medical records.
During the colonoscopy procedure, two mucosal biopsies were taken from the left colon and analysed. “We conclude that microbiota encroachment is a feature of insulin resistance-associated dysglycemia in humans,” the researchers said. The researchers said they were conducting follow-up studies to determine the identity of the bacteria that are invading the colon lining and are exploring remedies to prevent such bacteria encroachment.