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Center for Obesity and METabolic Health (COMET)


Our Team

The obesity and metabolic health team comprises a highly skilled core group of physicians and scientists with a broad range of expertise in lipid metabolic, genetic, surgical, endocrine, neurophysiologic, and imaging models to study the effects of obesity in both animals and humans. This collective group of the best scientists and clinicians at UCLA shares the vision of an integrative approach to treating and studying patients with obesity and metabolic dysfunction.

Medical Director »  |   Surgical Director »   |   Digestive Diseases »   |   Bariatric Surgery »   |   Clinical Nutrition »   |   Pathology and Laboratory Medicine »

Medical Director

Simon W. Beaven, MD, PhD
Research and Medical Director, Center for Obesity and Metabolic Health (COMET)
Director, Metabolic Syndrome Research
Health Sciences Assistant Clinical Professor of Medicine
Vatche and Tamar Manoukian Division of Digestive Diseases and Pfleger Liver Institute

Dr. Beaven attended Stanford University where he majored in mathematics with honors in humanities. He went on to receive his MD from the University of California, San Francisco, and received the Dean's Research Prize for work he performed in the laboratory of Dr. Scott Friedman under a Howard Hughes Medical Student Research Fellowship. Dr. Beaven completed internal medicine residency training at the Brigham & Women's Hospital and Harvard Medical School in Boston. He came to UCLA in 2003 as a fellow in digestive diseases where he completed his gastroenterology fellowship. During this period, Dr. Beaven continued his research training and received a PhD with Dr. Peter Tontonoz in the Howard Hughes Medical Institute and Department of Pathology. His doctoral work focused on cholesterol and lipid metabolism as it pertains to an important clinical problem: the metabolic syndrome. His research interests include nuclear receptor signaling and the relationship of inflammation to lipid metabolism during chronic liver injury.

Dr. Beaven joined the digestive diseases faculty at UCLA as an assistant professor in 2010. He is the research director for COMET, the Center for Obesity and Metabolic Health, which studies (in part) how metabolic pathways influence liver and gastrointestinal diseases. His molecular biology laboratory investigates how nutrient homeostasis impacts the development of liver fibrosis and diabetes. In particular, his team studies the biology of the hepatic stellate cell, the key scar-forming cell in all forms of liver disease (e.g. fatty liver, viral hepatitis, alcoholic liver disease). COMET has active protocols to enroll and study patients with metabolic syndrome, identify the genetics that influence liver fibrosis, and is developing novel tools to improve the delivery of care to patients with liver disease. Dr. Beaven and his trainees have received awards from the UCLA Department of Medicine Research Day, UCLA CURE, and the American Association for the Study of Liver Diseases (AASLD). He is an active peer reviewer for several scientific journals, including Diabetes, Molecular & Cellular Biology, Hepatology, Gastroenterology, and the Journal of Lipid Research. Dr. Beaven teaches in the medical school at all levels and lectures to medical residents and fellows on issues related to liver and gastrointestinal disease. He primarily sees patients with liver diseases as well as patients enrolled in the research protocols related to COMET. 


Surgical Director

Erik Dutson, MD, FACS
Surgical Director, Center for Obesity and Metabolic Health (COMET)
Chief, Minimally Invasive and Bariatric Surgery
Executive Medical Director, Center for Advanced Surgical & Interventional Technology (CASIT)
Clinical Professor of Surgery

Dr. Erik Dutson received his bachelor of science degree in 1990 from The College of William and Mary in Williamsburg, VA where he was on the Dean's List. He attended medical school at Eastern Virginia Medical School, receiving his MD degree in 1995. After completing medical school, he remained in Norfolk, VA to complete his general-surgery-residency training, which he completed with honors in 2000 under Dr. L.D. Britt. Seeking to further his excellent clinical experience, he worked for one year as a locum tenens surgeon, which gave him the opportunity to participate in a variety of practices in different hospitals all over the country while helping out communities in dire need of a well-trained general surgeon. An increasing interest in advancing surgical technologies guided Dr. Dutson to Strasbourg, France, where he worked for two years as a clinical and research fellow at the European Institute for Telesurgery at the University of Louis Pasteur. During this time, he learned a wide variety of advanced minimally invasive surgical techniques from a conglomeration of world-renowned experts. He participated in robotic-surgical investigations, and helped develop and validate virtual- and augmented-reality applications for surgery. As part of this experience, he participated in the training of approximately 8,000 surgeons from all over the world in advanced laparoscopic procedures, and worked on a day-to-day basis with the team that performed the first-ever transatlantic telerobotic long-distance surgical procedure.

Upon returning to the United States, he joined the newly formed minimally invasive section of UCLA's Department of Surgery in September 2003. He presently serves as co-director of UCLA's Center for Advanced Surgical and Interventional Technology (CASIT), a multidisciplinary laboratory with participation by the UCLA schools of medicine, engineering, computer science, and applied mathematics. He is a regular panel reviewer for NASA's National Space Biomedical Research Institute.

Dr. Dutson is board-certified in surgery and an active member in the Society of American Gastrointestinal and Endoscopic Surgeons (SAGES), the American College of Surgeons (ACS), the Society of Laparoendoscopic Surgeons (SLS), the Minimally Invasive Robotic Association (MIRA) and the American Society of Bariatric Surgery (ASBS). He has authored multiple scientific papers that have been published in peer-reviewed surgical and engineering journals. He has also spoken at numerous local, national and international meetings, as well as having helped to develop CME accreditation for web-based surgical education and worked as a web-based editor and author of surgical texts. He has been a visiting professor at both national and international venues, where he has also served as surgical proctor performing demonstrative advanced laparoscopic procedures. His clinical interests include laparoscopic and robotic bariatric surgery; laparoscopic gastric, upper and lower intestinal surgery; minimally invasive hiatal, paraesophageal, inguinal, ventral and incisional herniorrhapy; laparoscopic adrenalectomy and splenectomy; laparoscopic liver surgery and flexible endoscopy.


Digestive Diseases


Joseph Pisegna, MD
Chief, Division of Gastroenterology, Hepatology and Parenteral Nutrition
Veterans Administration Greater Los Angeles Healthcare System, Wadsworth VA
Professor-In-Residence of Medicine
Vatche and Tamar Manoukian Division of Digestive Diseases
David Geffen School of Medicine at UCLA

Dr. Pisegna's main research interest is the molecular pharmacology of hormones and receptors in the gastrointestinal tract. These research and clinical interests derive from research in the biochemistry and physiology of neuroendocrine tumors as well as an understanding of the molecular interaction of peptide hormones and their receptors. His clinical efforts are currently focused on the management of gastric hypersecretory conditions, neuroendocrine tumors of the GI tract, and Zollinger Ellison Syndrome (ZES), medical conditions that derive from alterations in the expression of gastrointestinal hormones. Dr. Pisegna cloned the receptor for pituitary adenylate cyclase activating polypeptide (PACAP), which is in the vasoactive intestinal polypeptide family of peptides and the calcitonin gene related peptide (CGRP). He has demonstrated that PACAP is a potent stimulant of gastric acid secretion and is expressed on neurons innervating the stomach, with enterochromaffin-like cells (ECL) of the stomach expressing receptors for PACAP. Using mice lacking the PAC1 receptor, he has demonstrated that the mice develop a gastric acid hypersecretory condition resulting from hypergastrinemia. Recently developed VIP knockout mice have been demonstrated to have abnormal gastrointestinal motility. More recently Dr. Pisegna's research interests extend to understanding the mechanisms involved in satiety with a research focus in treating obesity disorders.


Claudia Sanmiguel, MD
Program Director, Ingestive Behavior and Obesity Program
Health Sciences Assistant Clinical Professor of Medicine
Vatche and Tamar Manoukian Division of Digestive Diseases

Dr. Claudia Sanmiguel has joined the division faculty as program director of the Ingestive Behavior and Obesity Program, where she is conducting research on brain-gut interactions with an emphasis on the role of the brain in the development of obesity. Dr. Sanmiguel's clinical expertise is in gastrointestinal motility disorders, including achalasia, spastic disorders of the esophagus, gastroesophageal reflux (GERD), gastroparesis and motor disorders of the colon and anorectal region. She has published original research on gastrointestinal manometry/intraluminal impedance and on the effect of electrical stimulation on GERD, gastroparesis and constipation; as well as in obesity and diabetes.

After graduating from the Pontificial Javeriana University School of Medicine in Bogota, Colombia, Dr. Sanmiguel completed her internship and residency training in internal medicine at the UCLA/Cedars-Sinai Medical Center and fellowship in gastroenterology at the UCLA Division of Digestive Diseases. She practiced gastroenterology in her native country of Colombia before moving to Canada and then the United States to pursue her interest in research on motility disorders. As part of her research training, she spent time at the University of Alberta in Edmonton, Canada, and two years at the Cleveland Clinic as a research fellow in gastrointestinal motility. She also worked as a researcher in the GI Motility Program at Cedars-Sinai Medical Center.


Rabindra R. Watson, MD
Director, Faculty Career Development in Advanced Endoscopy
Assistant Clinical Professor of Medicine
Vatche and Tamar Manoukian Division of Digestive Diseases
David Geffen School of Medicine at UCLA

Dr. Watson's clinical interests include the diagnosis, treatment and palliation of various gastrointestinal cancers with a focus on minimally-invasive treatment strategies. He is proficient in the application of advanced therapies; including pancreatic endotherapy, EUS-guided access and drainage of the biliary tree, endoscopic pancreatic necrosectomy, and endoscopic suturing for fistula and perforation closure. Other interventional therapies performed include EUS with fine-needle aspiration, endoluminal stenting, deep enteroscopy, altered anatomy ERCP, endoscopic mucosal resection and polypectomy.

Dr. Watson serves as the bariatric endoscopist at the UCLA Center for Obesity and Metabolic Health (COMET), where he is pursuing investigations in the emerging field of bariatric endoscopy. He is active in the development and testing of these novel therapeutic endoscopic techniques which include primary endoscopic therapies for obesity, endoscopic treatment of weight regain following bariatric surgery, and treatment of post-surgical complications.

Dr. Watson completed his residency in internal medicine and fellowship in gastroenterology at the University of California, San Francisco. He then went on to complete an advanced endoscopy fellowship at Massachusetts General Hospital and Brigham and Women's Hospital. He is board-certified in gastroenterology and internal medicine, and is a member of the American Society of Gastrointestinal Endoscopy, the American College of Gastroenterology, American Gastroenterological Association, and American Society for Metabolic and Bariatric Surgery. He was also selected Super Doctors Rising Star in 2015 and 2016. 


Bariatric Surgery


Yujin Chen, MD
Assistant Clinical Professor of Surgery
Minimally Invasive/Bariatric Surgery
Department of Surgery
David Geffen School of Medicine at UCLA

Dr. Chen specializes in bariatric, hernia, minimally invasive and foregut surgery. Board-certified in surgery, Dr. Chen earned his medical degree at Fourth Military Medical University in China. He then did his postdoctoral research fellowship at UC Irvine and Stanford University. While doing his general surgery residency at Stanford, Dr. Chen developed a strong interest in helping obese patients. He then did his bariatric/minimally invasive surgery fellowship at Duke. Dr. Chen joined the UCLA minimally invasive/bariatric surgery program in 2014.   

Dr. Chen's research focuses pathophysiology of obesity, especially the cancer prevention mechanisms of weight loss surgery. He is also interested in the long term outcome of bariatric surgery and all the new obesity treatment technologies. 


Clinical Nutrition


Zhaoping Li, MD, PhD
Center Director and Division Chief, Clinical Nutrition
Professor of Clinical Medicine

Dr. Li completed her MD and PhD in physiology at Bejing University. Her residency training was completed at the UCLA-VA internal medicine program in 1996 where she also served as chief medical resident. Dr. Li has been a faculty member at UCLA and VA Greater Los Angeles Health Care System since 1997. Dr. Li is board-certified in internal medicine and is a physician nutrition specialist.


Pathology and Laboratory Medicine

Cynthia Hong, PhD
Associate Director of Technology Development, Center for Obesity and Metabolic Health
Assistant Researcher - Research Professor
Department of Pathology and Laboratory Medicine
David Geffen School of Medicine at UCLA

Dr. Hong received her doctoral degree in biomedical engineering from UCLA in 2008. Subsequently, she completed a post-doctoral training under the mentorship of Dr. Peter Tontonoz in the Howard Hughes Medical Institute and UCLA's Department of Pathology and Laboratory Medicine. Her work focused on understanding the underlying biological mechanisms of cholesterol homeostasis and how molecular perturbations to this balance impact metabolic diseases. 
In 2012, Dr. Hong joined the Department of Pathology and Laboratory Medicine's research faculty where she continues to address questions focused on lipid and sterol metabolism. In 2014, she received the Roger Davis Investigator Award for Transitional Faculty in lipid metabolism. Dr. Hong has received independent funding from the American Heart Association, the American Diabetes Association, Center for Ulcer Research and Education (CURE) and UCLA/UCSD Diabetes Research Center (DRC). 

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