Since the Human Microbiome Project was established by the National Institute of Health in 2008, clinicians and researchers have come a long way in understanding how changes in our microorganisms, specifically bacteria, may correlate to certain diseases—such as diabetes.

Ruchi Mathur, MD, endocrinologist and director of the Diabetes Outpatient Teaching Education Center at Cedars-Sinai, is researching the connection between the microbiome and Type 2 diabetes, specifically investigating a sub-classification of Type 2 diabetes associated with the microbiome.

"The way we classify diabetes is going to change," Mathur says. "In the future, we'll be looking at Type 2 diabetes and dividing it further into what we might call Type 2a microbiome-associated diabetes, Type 2b, etc."

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Almost half of all the cells in the human body aren't human at all—they're microbial. 

The interplay between the human host and its bacterial inhabitants is "ancient and complex," Mathur says, making this area of research one of "intense interest and exploration."

This is where the Medically Associated Science and Technology (MAST) program at Cedars-Sinai comes in. Mathur is part of a team of investigators in MAST who are studying the small bowel microbiome. One of these current studies, known as REIMAGINE, is a large-scale study that looks at the microorganisms in the small intestine, along with multiple biological and anthropomorphic parameters. 

The purpose of the study is to examine how the small intestinal microbial "fingerprint" may change in various disease states, such as diabetes. 

"By characterizing these changes, we can focus on where to personalize interventions," notes Mathur. 

Up until now, investigators have largely relied on stool samples to characterize the gut microbiome. However, Mathur says it's important to look at the small intestine specifically. This is what makes MAST and the REIMAGINE initiative so innovative in its approach.

"Stool is great, but the small intestine is where we're seeing a more accurate picture of the microbiome in the small bowel," Mathur says. "Changes in the small bowel may not be accurately reflected when we simply focus on stool."

More on the research at the Mathur Lab at Cedars-Sinai.

Investigators such as Mathur hope to better illustrate how a person's own genetic and metabolic profile interacts with the gut microbiome. The interplay may influence insulin resistance, inflammation and metabolism. 

Mathur says that when it comes to metabolic diseases such as obesity and diabetes, a common thread is that there is a lack of microbial diversity in the stool.

"If you look at someone who is eating a North American diet and compare them to someone eating a diet rich in plant fibers, the person consuming a plant-rich diet tends to have more microbial diversity in the gut," Mathur explained in an interview with Endocrine Today. "Diversity is a good thing. A Western diet high in fast food and processed food alters the gut microbiome such that the microbial diversity is much less. We know that is not a healthy change." 

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Once investigators identify microbial patterns that are associated with human disease, the potential is "enormous," Mathur says. 

"Imagine if, in a subset of humans with chronic diseases such as diabetes, we could alter the microbiome in a beneficial way, such that we could reduce the burden of disease on the human host," Mathur says. "That would be groundbreaking and life-changing. Our group is trying to move the science in that direction."