Research Areas

Currently an estimated 30 million people in the United States have diabetes and another 80 million have prediabetes—that's one in every three. Forty percent of adults in the U.S. are obese, and the most recent statistics show an alarming increase in obesity in youth, with over 20 percent of adolescents in the country dealing with obesity. Although the medical community continues to fight the epidemics of diabetes and obesity, success is elusive. Both of these diseases are obviously multifactorial, but in the Mathur Laboratory, we think perhaps one piece of the puzzle deserves a bit more exploration—the gastrointestinal microbiome.

Microbial fermentation in the human gut. (A) In the absence of H2-utilising methanogens, the build-up of H2 results inhibition of fermentation. (B) In the presence of H2-utilising methanogens, H2 build-up is alleviated, facilitating increased polysaccharide fermentation and increased availability of SCFAs to the host. CH, carbohydrate. Image via: Intestinal methane production is associated with decreased weight loss following bariatric surgery.

The Mathur Laboratory has shown an association in obese subjects between a greater body mass index and methane production. Animal work in the Mathur Lab has shown that rats colonized with the enteric methanogen Methanobrevibacter smithii (M. smithii) exhibit significant increases in weight gain when fed high-fat chow, which correlated with increases in M. smithii levels but not in levels for total bacteria. Another study showed that, in humans, the eradication of M. smithii (as measured by methane on breath), using antibiotics, resulted in significant improvements in low-density lipoprotein and total cholesterol levels, as well as lower blood glucose and insulin levels on oral glucose tolerance test. Clarifying whether the methanogen M. smithii, and its effects on other microbes, or the methane gas alone are responsible for these results will allow researchers to work toward a possible pharmaceutical intervention.

The Mathur Laboratory is currently taking a closer look at the relationship of M. smithii with weight and metabolism by exploring whether the use of a non-absorbable antibiotic (one that stays solely in the gastrointestinal tract and targets methanogens) can either attenuate weight gain or enhance weight loss in a group of animals on a high-fat diet.

Current Research Studies in the Mathur Laboratory

Polycystic Ovary Syndrome Androgens Study

The goal of this study is to define the contribution of gut microbes to circulating androgen levels. Research includes transplanting fecal material from subjects with polycystic ovary syndrome, female control subjects with normal androgen levels and male control subjects with normal androgen levels into male and female rats rendered virtually devoid of endogenous androgen production.

Small Intestinal Microbiome Sampling Study

Researchers in this study will collect a comprehensive set of human tissue and corresponding microbiome samples from different locations within the small bowel, as well as associated blood and stool samples. These samples will be used to elucidate the mechanisms by which the small bowel microbiome affects the human host and contributes to the development of gut-related human diseases. By examining how various gut microbes may be affected by genetic makeup and how microbes affect which genes are turned on or off in various parts of the gut, researchers hope to better understand how gut microorganisms may contribute to gut-related diseases.

Valeant Rifaximin Study

The goals of this study are to determine the effects of ongoing treatment with rifaximin on body weight, total body fat and glucose and insulin responses in a rat model, and to begin determining the associated effects on gut microbial populations.

Contact the Mathur Lab

8700 Beverly Blvd.
Davis Building, #5009
Los Angeles, CA 90048