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 / Interventional endoscopy | Bariatric surgery | Clinical nutrition | Pathology and laboratory medicine
Simon W. Beaven, MD, PhD
Chief of Gastroenterology, Olive View-UCLA Medical Center
Research and Medical Director, Center for Obesity and Metabolic Health (COMET)
Director, Metabolic Syndrome Research
Health Sciences Associate 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.
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.
Danny Issa, MD
Health Sciences Clinical Instructor of Medicine
Vatche and Tamar Manoukian Division of Digestive Diseases
David Geffen School of Medicine at UCLA
Dr. Issa is an interventional gastroenterologist with advanced fellowship training. His clinical and research interest focus on using minimally-invasive approaches to the diagnosis and treatment of digestive diseases such as the pancreas and biliary tract disorders, achalasia, Barrett’s esophagus, gastroparesis, colon polyps and early cancer lesions. Gastrointestinal procedures he performs include endoscopic retrograde cholangiopancreatography (ERCP), therapeutic endoscopic ultrasound (EUS), tumor ablation, endoluminal stenting, mucosal resection (EMR), endoscopic submucosal dissection (ESD) and peroral endoscopic myotomy (POEM). He has a particular interest in bariatric endoscopy and obesity medicine and performing non-surgical endoscopic procedures for weight loss such as endoscopic sleeve gastroplasty (ESG) and gastric balloon placement. Dr. Issa has presented his research at numerous national meetings.
After earning his medical degree from the University of Damascus, he completed a postdoctoral research fellowship at Northwestern University, Chicago, and a residency in internal medicine at Cleveland Clinic - Fairview Hospital. He then completed a fellowship in gastroenterology and hepatology at Virginia Commonwealth University and an advanced endoscopy fellowship at Weill Cornell Medical College/ New York-Presbyterian Hospital. Dr. Issa is board-certified in gastroenterology and internal medicine. He is an active member of the American Society for Gastrointestinal Endoscopy (ASGE), American Gastroenterology Association (AGA), American Association for the Study of Liver Diseases (AASLD) and the American College of Gastroenterology (ACG).
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 molecular 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 human cholecystokinin A (CCKA), the cholecystokinin B (CCKB or gastrin) receptor and the pituitary adenylate cyclase activating polypeptide (PACAP) receptor. He has previously demonstrated that PACAP is a potent stimulant of gastric acid secretion and is expressed on neurons innervating the stomach, on 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 his lab is focused on understanding the role of peptide hormones in the development of obesity, metabolic syndrome and NAFLD. Dr. Pisegna's research interests extend to understanding the molecular mechanisms involved in satiety and metabolic syndrome including the role of the gastrointestinal microbiome.
Alireza Sedarat, MD
Health Sciences Assistant Clinical Professor of Medicine
Vatche and Tamar Manoukian Division of Digestive Diseases
David Geffen School of Medicine at UCLA
Dr. Sedarat joined UCLA in 2013 as a member of the interventional endoscopy within the Vatche and Tamar Manoukian Division of Digestive Diseases. His clinical interests encompass the development and application of advanced endoscopic techniques and interventions to diagnose, stage, treat and palliate a range of benign and malignant gastrointestinal disorders. He is proficient in the application of advanced endoscopic techniques including therapeutic ERCP, EUS with fine needle aspiration and biopsy, ERCP in surgically altered anatomy, interventional EUS (such as biliary drainage or rendezvous procedures, pancreas pseudocyst drainage, pancreas necrosectomy, fiducial placement and abscess drainage), pancreatic and biliary endotherapy, endoluminal stenting, endoscopic mucosal resection (EMR), endoscopic submucosal dissection (ESD), complex polypectomy, tumor ablation, deep (device assisted) enteroscopy, endoscopic fistula and leak closure, complex stricture dilation and endotherapy, endoscopic treatment of Barrett’s esophagus with mucosal resection and radiofrequency ablation, endoscopic antireflux procedures, Zenkers’ diverticulum myotomy, endoscopic management of surgical complications, and chromoendoscopy. Dr. Sedarat also performs bariatric endoscopy, including primary endoscopic therapies for obesity, endoscopic treatment of weight regain following bariatric surgery, and treatment of post-surgical complications.
He started the program at UCLA to offer the POEM procedure (peroral endoscopic myotomy) as treatment option for patients with achalasia and spastic disorders of the esophagus. His research interests include endoscopic device development and application as well as evaluation of existing and emerging endoscopic technologies with a focus on improving patient outcomes. He is interested in the application of the emerging fields of submucosal and transluminal endoscopy, including endoscopic submucosal dissection (ESD) for early tumor resection, POEM, and application of devices and techniques to treat gastrointestinal disorders that traditionally were managed surgically.
Dr. Sedarat completed his residency in internal medicine at the University of Pennsylvania. He completed his fellowship in gastroenterology here at UCLA and returned to UPenn to complete an advanced endoscopy fellowship. He is board-certified in gastroenterology and internal medicine and is a member of the American Society of Gastrointestinal Endoscopy, American College of Gastroenterology and American Gastroenterological Association.
Adarsh M. Thaker, MD
Health Sciences Clinical Instructor of Medicine
Vatche and Tamar Manoukian Division of Digestive Diseases
David Geffen School of Medicine at UCLA
Dr. Thaker is an advanced endoscopist with particular interest in minimally invasive endoscopic procedures which help fill the gap between medical management and traditional surgery. He is spearheading the growth of the bariatric endoscopy program at UCLA, coordinating with a multidisciplinary team in the UCLA Center for Human Nutrition and the Center for Obesity and METabolic Health (COMET). He performs endoscopic sleeve gastroplasty (ESG) for weight loss as well as gastric revision procedures, such as transoral outlet reduction (TORe), for patients who have regained weight after prior gastric surgery. He also performs the transoral incisionless fundoplication (TIF) procedure, which is a minimally invasive alternative to surgery for the treatment of acid reflux.
In addition, Dr. Thaker has specialized training in other advanced therapies, including including endoscopic mucosal resection (EMR) of large polyps; radiofrequency ablation for Barrett's esophagus and early esophageal cancer; stricture dilation; endoscopic retrograde cholangiopancreatography (ERCP); cholangioscopy; endoluminal stent placement; deep enteroscopy/balloon enteroscopy; endoscopic suturing, fistula and leak closure; and endoscopic ultrasound (EUS) for cancer staging, fine needle aspiration and biopsy and other interventions.
Dr. Thaker is board certified in gastroenterology and internal medicine. Dr. Thaker's research has focused on eliminating endoscope-related infections to improve patient safety, helping to develop and implement the use of the world's first available disposable duodenoscope. He has published several research studies, literature reviews, editorials, and a textbook chapter related to the endoscopic management of complex gastrointestinal diseases, anesthesia safety during endoscopy, and preventing infections related to endoscopic instruments.
Dr. Thaker serves on the national committee for the American Gastroenterological Association's (AGA) Center for GI Innovation and Technology (CGIT), which supports innovation and the development of new technologies for use in gastroenterology, hepatology, nutrition and obesity management. He is a member of the American Society of Gastrointestinal Endoscopy (ASGE), the Association for Bariatric Endoscopy (ABE), and the American College of Gastroenterology (ACG). He completed his undergraduate training in chemical engineering at UCLA before attending medical school at New York Medical College. He completed his internal medicine residency training at Beth Israel Deaconess Medical Center and Harvard Medical School in Boston, followed by gastroenterology fellowship and advanced endoscopy fellowship training at UCLA. In additional to performing procedures at UCLA Health campuses in Westwood and Santa Monica, Dr. Thaker performs advanced procedures in other Southern California locations.
Yijun 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.
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.
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).
