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Mark Pimentel, MD, FRCP

California | United States of America

Mark Pimentel, M.D., is Professor of Medicine, Geffen School of Medicine and Associate Professor at Cedars‐Sinai Medical Center in Los Angeles, California. Dr. Pimentel completed 3 years of an undergraduate degree in honors microbiology and biochemistry at the University of Manitoba, Canada. This was followed by his medical degree, and his BSc (Med) from the University of Manitoba
Health Sciences Center in Winnipeg, Manitoba, Canada, where he also completed a residency in internal medicine. His medical training includes a fellowship in gastroenterology at the UCLA Affiliated Training Program. Active in research, Dr. Pimentel has served as a principal investigator or co‐investigator for numerous basic‐science, translational and clinical studies in such areas as IBS,
and the relationship between gut flora composition and human disease. His work has been published in the New England Journal of

Medicine, Annals of Internal Medicine, American Journal ofPhysiology, American Journal of Medicine, American Journal of Gastroenterology and DigestiveDiseases and Sciences, among others. Dr. Pimentel has been invited to present his work at meetings,grand rounds, and advisory boards in the United States and Internationally. He is diplomate of theAmerican Board of Internal Medicine (Gastroenterology) and a fellow of the Royal College ofPhysicians and Surgeons of Canada. Dr. Pimentel is also a member of several medical associationsincluding the American Gastroenterological Association, the American College of Gastroenterology,and the American Neurogastroenterology and Motility Society.


A few of Dr. Pimentel’s most significant accomplishments include:


1. The discovery of rifaximin as a treatment for irritable bowel syndrome (IBS)

2. He developed the first blood test for IBS on the basis of IBS being derived from acutegastroenteritis

3. Described the association between IBS and bacterial overgrowth which forms the basis formicrobiome therapies in this condition

4. Uncovered the methanogen (M. smithii) as an agent for causing constipation in humans.5. Discovered the use of lovastatin as a microbiome treatment for constipation on the basis ofinhibiting methane production by methanogens

"SIBO In 2020"

In the next 12 months there is expected to be a major shift in how SIBO is understood and managed. Some of the major inflexion points have not yet been published but much is already known. A new paper in the Am J Gastroenterology essentially sums up 20 years of research on the association between SIBO and IBS. It is clear that a large proportion of IBS is SIBO. The paper further verifies that methane is linked to constipation and PPI therapy is not associated with SIBO. While these findings are not new, the study caps off a long and controversial road now with hard and global data. Advancing from this, 2020 will bring forth gas to breath testing. Hydrogen sulfide testing will add to hydrogen and methane whereby this new gas is associated with diarrhea. Testing for this will soon be available. In other testing, it is now understood that IBS and SIBO could be derived from food poisoning and that IBS is an autoimmune disease. This finding is ever expanding and anti-vinculin/anti-CdtB testing is becoming mainstream. Finally, there is the potential for new revelations in the treatment of methane. Methane is believed to cause constipation and SYN-010 is a potential remedy. It is expected that the first major trial using this novel delivery of drug could change the treatment of constipation related to methane. While FDA approval is still a year or two away in the best case scenario, there is optimism for the future.

Learning Objectives:

  • Apply contemporary SIBO diagnostic and therapeutic modalities in your practice. 

  • Understand the evolving role of breath testing and particularly H2S in the testing for SIBO. 

  • Apply current understanding and scientific evidence for the role of autoimmunity in SIBO/IBS.

Past Conference Participation 

2020 Integrative SIBO Conference - San Diego, California

~Featured Speaker~

"SIBO In 2020"

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