Researchers at Oregon State University have discovered that a few organisms in the gut microbiome play an important role in type 2 diabetes, opening the door to probiotic therapies that may exist for a severe metabolic disease that affects approximately one in 10 Americans.
Type 2 diabetes is indeed a pandemic worldwide and the number of diagnoses is expected to continue to rise over the next decade. One of the main ingredients is the so-called ‘western diet’ – high in saturated fat and refined sugars. But gut bacteria play an important role in altering the effects of diet. “
Andrey Morgun, Associate Director of Research, Associate Professor of Pharmaceutical Sciences, OSU College of Pharmacy
Formerly known as adult-onset diabetes, type 2 diabetes is a chronic condition that affects the way the body metabolizes glucose, a sugar that is the main source of energy. For some patients, this means that their body is resistant to the effects of insulin – the hormone secreted by the pancreas that opens the door for sugar to enter cells. Other patients do not make enough insulin to maintain normal glucose levels.
In all cases, sugar accumulates in the bloodstream and if left untreated the effects adversely affect many major organs, sometimes to impaired or life threatening levels. Obesity is a major risk factor for type 2 diabetes, often as a result of a western diet combined with low physical activity.
Human gut microorganisms produce over 10 trillion microphone cells from approximately 1,000 bacterial species. Dysbiosis, or imbalance, in the microbiome is often associated with adverse effects on a person’s health.
“Some studies suggest that dysbiosis is caused by complex changes due to the interaction of hundreds of different microbes,” said Natalia Shulzhenko, associate professor of biochemical sciences in Carlson College of Medicine at OSU and another co-director of the study. “However, our study and other studies suggest that individual members of the microbial community, altered by diet, may have a significant impact on the host.”
Shulzhenko and Morgun used a new, data-driven biological systems approach, called transkingdom network analysis to study host-microbe interactions under a western diet. This allowed them to investigate whether individual members of the microbiota were involved in metabolic changes caused by the diet in a host.
“The analysis identified specific microbes that may affect a person’s metabolism of glucose and lipids,” Morgun said. “More importantly, it allowed us to make decisions about whether these effects are harmful or beneficial to the host. And we found links between these microbes and obesity.”
The scientists identified four functional taxonomic units, or OTUs, that appeared to affect glucose metabolism; OTUn is a method of classifying bacteria according to gene sequence appearance.
The identified OTUs corresponded to four bacterial species: Lactobacillus johnsonii, Lactobacillus gasseri, Romboutsia ilealis and Ruminococcus gnavus.
“The first two microbes are thought to be potential ‘enhancers’ in glucose metabolism, the other two ‘getting worse,'” Shulzhenko said. “The overall indication is that types microbes and / or their interactions, and not community-level dysbiosis, are key players in type 2 diabetes. “
The researchers would feed mice similar to the western diet and then supplement the introduction of rodents with the advanced and deteriorating microbes. The Lactobacilli promoted mitochondrial health in the liver, resulting in improvements in the guest’s metabolism of glucose and lipids, and the mice receiving these Lactobacilli had a lower fat index than those that fed only the western diet.
Examining the results of the mouse against data from an earlier human study, the scientists found a correlation between human body mass index and the abundance of the four bacteria – more of the supplements meant a better body index. better, more of the culprits were linked to a less healthy BMI. .
“We found that R. ilealis was present in more than 80% of obese patients, suggesting that the microbe may be a common pathobiont in obese people,” Shulzhenko said.
A pathobiont is an organ that usually has a symbolic relationship with its host but may cause disease in certain circumstances.
“Overall, our observations support what we saw in western diet mice,” she said. “And in looking at all the metabolites, we found a few that explain a large part of the probiotic effects caused by Lactobacilli medications.”
Lactobacillus is a microbial genus that contains hundreds of different bacterial strains. Its agents are common among probiotics and are often found in many types of fermented foods and Lactobacillus fortified dairy products, such as yogurt.
“Our study highlights potential probiotic rays for the treatment of type 2 diabetes and obesity as well as insights into the mechanisms of their action,” Morgun said. an opportunity to develop targeted therapies rather than trying to restore ‘healthy’ microbiota in general. “
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Magazine Reference:
Rodrigues, RR, et al. (2021) Transkingdom interactions between Lactobacilli and hepatic mitochondria reduce diet-induced diabetes. Nature Communication. doi.org/10.1038/s41467-020-20313-x.