Pimentel Laboratory

Mark Pimentel, MD, is currently the head of the Pimentel Laboratory and executive director of the Medically Associated Science and Technology (MAST) Program at Cedars-Sinai. This program focuses on the development of drugs, diagnostic tests and devices related to conditions of the microbiome.

Mark Pimentel, MD

"It is increasingly clear that influencing the gut microbiome has the potential to revolutionize the management of not only infectious disease states but a broad range of other conditions in which the microbiome is now being shown to play a critical role."

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The Pimentel Lab researches irritable bowel syndrome (IBS), one of the most prevalent gastrointestinal (GI) conditions effecting about 10 percent of the population worldwide and about 10 to 15 percent of people in the U.S. In the past, there was no definitive test to diagnose IBS. For a time, IBS was thought to be a psychological disease; however, the Pimentel Lab discovered a blood test to provide a definitive diagnosis showing that IBS is an organic disease. Having a definitive diagnosis for IBS paved the way for additional research in the Pimentel Lab to treat the condition.

A few of the most significant accomplishments of the Pimentel Laboratory include:

  • The discovery of rifaximin as a treatment for irritable bowel syndrome (IBS) with diarrhea
  • Developing the first blood test for IBS on the basis of IBS being derived from acute gastroenteritis
  • Describing the association between IBS and small intestinal bacterial overgrowth (SIBO), which forms the basis for microbiome therapies in this condition
  • Determining IBS/SIBO to be an autoimmune disease
  • Developing the first animal model to study treatment of IBS/SIBO caused by gastroenteritis
  • Uncovering the methanogen Methanobrevibacter smithii (M. smithii) as an agent for causing constipation in humans
  • Discovering the use of lovastatin as a microbiome treatment for constipation on the basis of inhibiting methane production by methanogens

The Pimentel Laboratory, in collaboration with Ruchi Mathur, MD, whose work focuses on links between metabolic disease and gut microbiome, and Ali Rezaie, MD, whose innovative work in GI motility improves the well-being of patients, work together in the MAST program to find better treatments for the conditions related to the microbiome. The areas of greatest interest and work in the MAST program include motility disorders of the GI tract, SIBO, IBS, metabolic diseases (such as obesity) and many others, as they relate to the microbiome.