Gut Bacteria May Play a Role in Diabetes

Gut Bacteria May Play a Role in Diabetes

Summary: People with higher levels of Coprococcus gut bacteria tend to have higher insulin sensitivity, while those with higher levels of Flavonifractor have lower levels of insulin sensitivity. Researchers say specific gut bacteria may play an important role in the development of type 2 diabetes.

Source: Cedars Sinai Medical Center

One type of bacteria found in the gut may contribute to the development of type 2 diabetes, while another may protect against the disease, according to early results from an ongoing, prospective study led by investigators at Cedars-Sinai.

The study, published in the peer-reviewed journal Diabetes, found that people with higher levels of a bacteria called Coprococcus tended to have higher insulin sensitivity, while those whose microbiomes had higher levels of the bacterium Flavonifractor tended to have lower insulin sensitivity.

For years, investigators have sought to understand why people develop diabetes by studying the composition of the microbiome, which is a collection of microorganisms that includes fungi, bacteria and viruses that live in the digestive tract.

The microbiome is thought to be influenced by medications and diet. Studies have also found that people who do not process insulin properly have lower levels of a certain type of bacteria that produces a type of fatty acid called butyrate.

Mark Goodarzi, MD, Ph.D., director of the Endocrine Genetics Laboratory at Cedars-Sinai, is leading an ongoing study that is following and observing people at risk for diabetes to learn whether those with lower levels of these bacteria develop the disease. .

“The big question we hope to address is: Did the microbiome changes cause the diabetes or did the diabetes cause the microbiome changes?” said Goodarzi, who is the study’s senior author and principal investigator of the multicenter study called the Microbiome and Insulin Longitudinal Evaluation Study (MILES).

Investigators involved in MILES have been collecting information from black and non-Hispanic white adults between the ages of 40 and 80 since 2018. An earlier cohort study from the MILES trial found that cesarean delivery is associated with a higher risk for the development of prediabetes and diabetes.

For the latest study to come out of this ongoing trial, investigators analyzed data from 352 people without known diabetes who were recruited from Wake Forest Baptist Health System in Winston-Salem, North Carolina.

Study participants were required to attend three clinic visits and collect stool samples prior to the visits. The investigators analyzed data collected at the first visit. They performed genetic sequencing on stool samples, for example, to study the participants’ microbiomes, and specifically to look for bacteria that previous studies have found to be associated with insulin resistance.

Each participant also completed a dietary questionnaire and received an oral glucose tolerance test, which was used to determine the ability to process glucose.

The investigators found that 28 people had oral glucose tolerance test results that met criteria for diabetes. They also found that 135 people had prediabetes, a condition in which a person’s blood sugar levels are higher than normal, but not high enough to meet the definition of diabetes.

The research team analyzed the links between 36 butyrate-producing bacteria found in stool samples and a person’s ability to maintain normal insulin levels. They controlled for factors that may also contribute to a person’s diabetes risk, such as age, gender, body mass index and race. Coprococcus and related bacteria formed a network of bacteria with beneficial effects on insulin sensitivity.

Despite being a butyrate producer, Flavonifractor was associated with insulin resistance; Previous work by others has found higher levels of Flavonifractor in the stool of people with diabetes.

The microbiome is thought to be influenced by medications and diet. The image is in the public domain

The investigators are continuing to study samples from patients who participated in this study to learn how insulin production and microbiome composition change over time. They also plan to study how diet can affect the bacterial balance of the microbiome.

Goodarzi stressed, however, that it is too early to know how people can change their microbiome to reduce their risk of diabetes.

“In terms of the idea of ​​taking probiotics, that would really be somewhat experimental,” said Goodarzi, who is also the Eris M. Field Chair in Diabetes Research at Cedars-Sinai.

“We need more research to identify the specific bacteria we need to modify to prevent or treat diabetes, but that will come, probably in the next five to 10 years.”

See also

About this microbiome and diabetes research news

Author: Press Office
Source: Cedars Sinai Medical Center
Contact: Press Office – Cedars Sinai Medical Center
Image: Image is in the public domain

Original Research: Open Access.
“Butyrate-Producing Bacteria and Insulin Homeostasis: The Microbiome and Insulin Longitudinal Evaluation Study (MILES)” by Jinrui Cui et al. dIABETES

abstract

Butyrate-producing bacteria and insulin homeostasis: the Microbiome and Longitudinal Insulin Evaluation Study (MILES)

Gut microbiome studies have documented depletion of butyrate-producing taxa in type 2 diabetes. We analyzed associations between butyrate-producing taxa and detailed measures of insulin homeostasis, the dysfunction of which underlies diabetes in 224 non-Hispanic whites. and 129 African Americans, all of whom completed an oral glucose tolerance test. Faecal microbiome assessed by whole-metagenome shotgun sequencing with taxonomic profiling.

We examined associations between 36 butyrate-producing taxa (n = 7 genera and 29 species) and insulin sensitivity, insulin secretion, disposition index, insulin clearance, and prevalence of dysglycemia (prediabetes plus diabetes, 46% of the cohort), using adjusted for age, sex, BMI, and race.

Coprococcus genus was associated with higher insulin sensitivity (β = 0.14; P = 0.002) and mood index (β = 0.12; P = 0.012) and a lower rate of dysglycemia (odds ratio [OR] 0.91; 95% CI 0.85–0.97; P = 0.0025).

In contrast, Flavonifractor was associated with lower insulin sensitivity (β = -0.13; P = 0.004) and mood index (β = -0.11; P = 0.04) and higher prevalence of dysglycemia (OR 1.22; 95% CI 1.08-1.38; P = 0.0013). Species-level analyzes found 10 bacteria associated with beneficial directions of effects and two bacteria with negative associations in insulin homeostasis and dysglycemia.

Although the majority of butyrate producers analyzed appear to be metabolically beneficial, this is not the case for all such bacteria, suggesting that microbiome-directed therapeutic measures for the prevention or treatment of diabetes should be targeted at specific butyrate-producing taxa. and not all butyrate manufacturers.

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