Type 2 diabetes: How does the gut microbiome affect risk?

For this study, researchers analyzed data from the Microbiome and Cardiometabolic Disease Consortium (MicroCardio), which included 8,117 gut microbiome samples. metagenomes from participants of diverse ethnic and geographic backgrounds, including the United States, China, Israel, and Germany.

“Although research over the past decade has linked changes in the gut microbiome to the development of type 2 diabetes, previous studies have been too small and varied in design to provide strong conclusions,” said Daniel (Dong) Wang, MD, ScD, assistant professor of medicine in the Channing Division of Network Medicine at Brigham and Women’s Hospital and Harvard Medical School, associate member of the Broad Institute of MIT and Harvard, assistant professor in the Department of Nutrition at the Harvard T.H. Chan School of Public Health, and co-corresponding author of the study.

“There is still a significant gap in understanding the mechanisms, especially the biological pathways encoded by specific microbial strains, that underlie the link between the gut microbiome and type 2 diabetes,” Wang said. Today’s Medical News.

“In addition, previous research has focused on microbial species, but it is actually strains that are the relevant targets for potential interventions,” Wang continued. “To address these gaps, we launched this study in a large, diverse, and international population to seek more definitive answers.”

At the end of the study, Wang and his team reported finding several microbial species, as well as their functions within the gut microbiome, linked to the development of type 2 diabetes.

For example, researchers have identified a strain of the gut microbe Prevotella cover (P. copri), which is capable of producing large amounts of branched-chain amino acids (BCAAs), which were more frequently observed in the gut microbiome of people with type 2 diabetes.

“The discrete genetic structure and population-specific distributions of different P. copri strains are well documented in the microbiome field. However, the implication of these strain distributions in human health remains unexplored, so the study on this topic is important because P. copri is one of the most abundant microbial species in the human gut, and our previous research has demonstrated that it can predict individual responses to a healthy diet.

For the first time, this current study revealed that individual carriage of different strains of P. copri can explain interindividual differences in the risk of type 2 diabetes.

– Dr Daniel (Dong) Wang, ScD

“In addition, we found that P. copri strains linked to a higher risk of type 2 diabetes have an increased ability to produce branched-chain amino acids, metabolites that could potentially lead to type 2 diabetes, which provides a functional explanation for why individuals carrying certain strains have a higher risk of type 2 diabetes,” he added.

Wang and his team also found evidence suggesting that bacteriophages — viruses that only infect bacterial cells — may also cause changes in specific bacterial strains of the gut microbiome, leading to an increased risk of type 2 diabetes.

“Few studies have investigated the role of bacteriophages in chronic diseases such as type 2 diabetes; most previous research has focused on their role in infectious diseases,” Wang explained. “Our study is novel because we found that bacteria infected with bacteriophages may have different functions related to the pathology of type 2 diabetes. This infection could be an important driving force in the evolution of different microbial strains.”

“Our study is the first project of this international consortium on the human microbiome and cardiometabolic health that my group leads (MicroCardio Consortium). We have demonstrated the considerable potential of combining a large and diverse population with new analytical methods to generate new biological insights. We plan to maintain and expand this consortium, extending our research to other disease areas.”

– Dr Daniel (Dong) Wang, ScD

“In addition, we will delve deeper into the mechanisms, such as the in-depth study of bacteriophages and horizontal gene transfers in all gut bacteria and their implications in altering the inflammatory response and insulin resistance at the local level – the gut environment – ​​and in a systematic manner,” Wang added.

After reviewing the study, Dr. Rudolph Bedford, a board-certified gastroenterologist at Providence Saint John’s Health Center in Santa Monica, California, said: MNT That researchers have been studying the gut microbiome and how it may affect or cause diabetes for some time now.

“I think there’s probably something there and that insulin sensitivity may be regulated based on the type of bacteria that are in the gut, given that these bacteria are used to process a lot of foods and the byproducts, like fatty acids, can certainly affect insulin sensitivity, so to speak,” Bedford explained.

Bedford said it’s important for researchers to continue looking for factors that may increase the risk of developing type 2 diabetes, such as changes in the gut microbiome.

“We might be able to modulate their bacterial flora with things like probiotics, possibly dietary modifiers, in terms of regulating the gut microbiome in some positive ways,” he continued. “I would like to see the effect of probiotics on the development of insulin sensitivity in terms of the bacterial flora in the gut and see whether or not using probiotics might allow us to change the course of some prediabetic patients and see whether or not we have an effect on their insulin sensitivity.”