Our Team

The teaching faculty in the Departments of Surgery, Vascular Surgery, Laboratory Medicine and the Methodist Institute of Academic Medicine all have academic appointments with Weill Cornell Medical College and are members of the Houston Methodist Transplant Center, and the Methodist DeBakey Heart & Vascular Center. They are nationally recognized for their expertise in transplantation and sophisticated techniques. Faculty to trainee ratio is greater than 5: 1. The Abdominal Multi-organ Transplantation faculty include:


Liver Transplant Surgery


Osama Gaber, MD, FACS
A. Osama Gaber, M.D., is a Professor in the Department of Surgery at the Weill Cornell Medical College in New York, New York.  A senior member at Houston Methodist Hospital Research Institute in Houston, Texas, he also holds the Houston Methodist J.C. Walter Jr. Transplant Center Distinguished Endowed Chair.  Dr. Gaber is Director of the Houston Methodist J.C. Walter Jr. Transplant Center and Vice Chairman for Administration and Faculty Affairs at Houston Methodist Hospital in Houston.

Dr. Gaber has devoted much of his career to pancreas, liver, and kidney transplantation and the surgical care of organ failure patients.  He has been funded by the NIH, JDRF, Assisi Foundation, Vivian Smith Foundation, and many other national and local foundations.  He is the author of more than 270 papers, as well as more than 340 abstracts and numerous book chapters. Dr. Gaber founded Nora’s Life Gift Foundation to build Nora’s Home, a hospital hospitality house, located in the Houston Texas Medical Center for transplant patients and their families.  Nora’s Home offers transplant patients and their families an affordable place to stay where they can find support and share experiences with others, in the comfort of a home-like environment. 

Dr. Gaber has been active in transplant business and regulatory issues since his early days as Chair of the SEOPF Kidney-Pancreas Committee.  He has also served as Region 11 representative and member of the MPSC and the UNOS Board.  He was a founding member and President of the Tennessee Transplant Society.  He was also a committee member for both the ASTS and the AST and a councilor-at-large for ASTS, and currently Secretary for the ASTS.  Dr. Gaber previously chaired the Governor’s Task Force on Chronic Kidney Disease, and the Kidney Alliance (KAT) of Texas, a statewide partnership representing leading professional kidney organizations, clinicians, public health professionals, medical schools, caregivers and patients. Dr. Gaber also serves on the Network 14 Quality Committee.  He is a current member of the Texas Transplant Society.


R. Mark Ghobrial, MD, PhD, FACS, FRCS
Dr. Ghobrial attended Cairo University Medical School in Egypt, where he graduated in 1980 with an MD. He then completed his internship at the Massachusetts General Hospital in Boston and his surgical residency at The University of Texas Health Science Center/M.D. Anderson Cancer Center in Houston, Texas. His clinical fellowship in multi-organ transplantation was conducted at the Dumont-UCLA Liver Transplant Center. Dr. Ghobrial completed two postdoctoral basic science research fellowships in immunology: Harvard University in Boston and The University of Texas Medical School at Houston. He received his PhD in immunology from the Graduate School of Biomedical Sciences at The University of Texas.

As a researcher, Dr Ghobrial maintains an active laboratory for basic science studies that focuses on transplant immunomodulation and inhibition of chronic rejection. His clinical research interests include partial liver grafting, immunosuppression, clinical outcomes, organ allocation and living donation. He has been the principal or co-investigator of NIH-sponsored basic and clinical research studies, as well as many clinical trials associated with transplantation. Dr Ghobrial is an active reviewer for several scientific journals and a member of study sections for grant review panels for National Institute of Health (NIH), federal and private funding agencies. Additionally, he has authored or co-authored numerous journal articles and book chapters and has lectured widely, both nationally and internationally, on topics related to liver disease and transplantation.

Dr. Ghobrial is an active member of several surgical and transplantation societies including the American College of Surgeons (ACS), American Surgical Association (ASA) and American Association for Study of Liver Diseases (AASLD). He is involved in multiple committees and services to United Network for Organ Sharing (UNOS), American Society of Transplantation (AST), International Liver Transplant Society (ILTS), Transplant Recipient International Organization (TRIO) and American Liver Foundation (ALF). He served as Councilor-at-Large on the Board of Directors of the American Society of Transplant Surgeons (ASTS) and currently serves as a Counselor on the Board of Directors for ILTS and Chair of Investment Committee. Dr Ghobrial is the recipient of multiple awards and honors from the ACS, ASTS, and Juvenile Diabetes Research Foundation (JDRF). He was elected to the ASA and to the Fellowship of The Royal College of Surgeons-Edinburgh (FRCS, Ed).


Mark Hobeika, MD, FACS
Mark J. Hobeika, M.D., F.A.C.S. is a multi-organ abdominal transplant surgeon at Houston Methodist Hospital. His clinical practice includes liver transplantation, kidney transplantation, pancreas transplantation, and laparoscopic surgery for kidney donors. Dr. Hobeika joined the Houston Methodist Hospital transplant team in October, 2017.

Dr. Hobeika primary clinical interests include living donor kidney transplantation and liver transplantation using organs from donation after circulatory determination of death (DCD) donors. He is the founder of a multi-institutional collaborative project seeking to provide better transplant access and care to the Hispanic community and hosted the Inaugural Texas Medical Center Hispanic Transplant Symposium in 2016 and 2017. Dr. Hobeika is a member of the Board of Directors at Nora’s Home for Transplant Patients and Their Families, a non-profit organization providing comfortable housing and a sense of community for patients travelling to Houston for their pre- and post-transplant care. Additionally, Dr. Hobeika is an active member of the American Society of Transplant Surgeons serving as Chair of the the PROActor (PROviding better ACcess to ORgans) National Task Force and co-chair of the Donation after Circulatory Death National Task Force.


Constance Mobley, MD, PhD
Dr. Mobley is a board-certified surgeon in general surgery, surgical critical care, and transplant surgery. Dr. Mobley is active in education, and she has directed or served as faculty on numerous lectures and courses in topics covering general surgery, critical care and transplantation. She spearheads the critical care lecture series developed to teach ICU nurses, and residents the clinical management of liver failure patients at Houston Methodist. She serves as an active member on several hospital committees and professional societies, and is actively involved in the Diversity Committee for the American Society of Transplant Surgeons.

Dr. Mobley's areas of special interests include management of the critically ill liver failure patient, methodology to improve liver transplant success in high MELD patients, and management of cirrhotic cardiomyopathy and post-transplant cardiomyopathy. She has served as an invited presenter nationally, authored original manuscripts and reviewed peer journals in her field as well as contributing to several abstracts in her area of expertise. She is actively involved in several clinical research trials spanning transplant immunology, liver disease, and support devices to both prolong donor organ utility, and bridge to liver transplant.


Ashish Saharia, MD, FACS
Dr. Ashish Saharia received his initial training in General Surgery and Surgical Oncology from India.  He then trained as a fellow at St. Jude Children’s Research Hospital and did his Transplant Surgery Fellowship at University of Tennessee in Memphis. He did his General Surgery residency and joined faculty as an Associate Professor at Houston Methodist Hospital in 2009.

Dr. Saharia is Board certified in General Surgery and a member of the American Society of Transplant Surgeons. His main field of work is liver transplants and Hepatobiliary-pancreatic surgery. He is the coordinator for the residents who rotate through hepatobiliary surgery. His interests are in pancreatic cancers and living donor liver transplants which he hopes to advance at this hospital.

Dr. Saharia is a great teacher and enjoys mentoring students, residents, and fellows alike.  He is a great patient advocate and his patients love him.  He is a highly respected member of our faculty.  He has participated as sub-investigator in several clinical trials and has published several peer reviewed articles regarding kidney and liver transplantation.


Renal Transplant Surgery


Mark Hobeika, MD, FACS


Richard Knight, MD, FACS
Dr. Richard Knight is Surgical Director of Kidney and Pancreas Transplantation at the Methodist Hospital in Houston, Texas and Professor of Surgery at Weill Cornell Medical College. He earned his medical degree at Tulane University School of Medicine and completed his residency in General Surgery at the Mount Sinai School of Medicine in New York. He completed a surgical fellowship in Immunology and Organ Transplantation at the University of Texas Health Science Center in Houston, Texas as well as a clinical fellowship in pancreas transplantation at the University of Minnesota. He was previously an Assistant Professor of Surgery at the Mount Sinai School of Medicine and Associate Professor of Surgery at the University of Texas Medical School at Houston. He joined the staff at the Methodist Hospital in July 2007.

Dr. Knight’s clinical practice is focused on kidney and pancreas transplantation. His current research interests include the application of novel immunosuppressive protocols for renal-pancreas transplantation, understanding the role of donor specific antibodies in graft failure, and viral diseases in organ transplantation. He has published more than 90 papers, book chapters, and reviews. He has served in leadership roles for the American Society of Transplant Surgeons, the United Network of Organ Sharing, The Texas Transplant Society, and Life Gift Organ Donation Center.


Stephanie Yi, MD
Dr. Stephanie Yi completed her general surgery residency and abdominal transplant fellowship at Houston Methodist Hospital. She spent a year during her general surgery residency completing an outcomes research fellowship under the mentorship of Drs. Carol Ashton and Nelda Wray. She was awarded the American Board of Medical Specialties 2014-2015 Visiting Scholar award, which is a one-year research grant and part-time educational program funded by the American Board of Medical Specialties to promote research projects designed to improve patient care and help physicians advance their medical and professional skills. Dr. Yi currently works as faculty in transplant surgery at Houston Methodist Hospital, and takes courses part-time at the University Of Texas Health Sciences Center School Of Public Health.

Dr. Yi specializes in kidney and pancreas transplant surgery. She has a special interest in living donor kidney surgery, and strives to maintain excellent outcomes in both the donors and recipients. In addition to her surgical practice, Dr. Yi works with the Houston Methodist Outcomes Center studying surgical outcomes and quality improvement. She also spends her time studying ways to promote the quality of life in transplant patients.