Research Director

Dr. James Dunn

Dr. James Dunn has a background in biology, engineering, and medicine. Dr. Dunn obtained his B.S. degree in Biology and Chemical Engineering from the California Institute of Technology and his M.D. and Ph.D. degrees from Harvard and Massachusetts Institute of Technology. His research interest focuses on tissue engineering and regenerative medicine of the gastrointestinal system. Dr. Dunn’s laboratory is part of the NIH Intestinal Stem Cell Consortium, and is also funded by the California Institute for Regenerative Medicine for neural progenitor cell therapy. Dr Dunn has extensive experience with animal models of intestinal disease. His lab developed an in vivo model to test the ability of intestinal stem cells to self-renew and to differentiate into various cell lineages. Dr. Dunn is also developing a device that will induce growth and lengthening of the intestine. 

Mission Statement


To generate missing tissue for infants and children with organ insufficiency



  • Understand the interaction between stem cells and their environment
  • Develop cell-based therapy for pediatric disorders
  • Define the effect of mechanical force on cell and tissue growth

Research Team

Chih-hsin Chen

After pursuing his graduate training in Maryland, Chih-hsin moved west to enjoy the sunshine in California.


He joined Stanford and began to explore various molecular pathways and animal models in order to understand the fundamentals of cell development and its relationship to disease progression. In addition to routine bench work, Chihhsin feels honored to have the opportunity to cooperate with teams to set up and manage labs. Currently he is focusing on utilizing enteric stem cells to advance his studies.

Chihhsin also devotes himself to spending time with his family and building LEGO models while he is off duty.


Sunnie Wong

Sunnie Wong, MD PhD is a general surgery resident on the Stanford Accelerated Surgeon Scientist Track.


Sunnie Wong, MD PhD, is a categorical general surgery resident on the Stanford Accelerated Surgeon Scientist Track. She is interested in the omentum and is fascinated by its exceptionally versatile surgical applications. She is investigating a population of regulatory T cells (Treg) that resides in the omentum, and is conducting animal studies to elucidate the role of these tissue-specific Treg in local and systemic immune tolerance. She believes that Treg cell-based therapy is a promising approach to improve the outcome of tissue and organ transplantation, as well as inflammatory bowel disease.


Gillian Fell, MD, PhD

Gillian is a senior scientist at Stanford University and a pediatric surgeon at Stanford-affiliated Kaiser Permanente Hospital in Santa Clara, CA.  


She loves caring for patients and pursuing research aimed at benefitting the patient populations she serves. Her current course of scientific study focuses on response to injury or disease and healing in intra-abdominal organs, with a specific focus on hepatic fibrosis and regeneration and intestinal anastomotic healing after bowel resection. She is also collaborating with colleagues in the Dunn laboratory studying intestinal lengthening utilizing springs in a porcine model; a project aimed at developing strategies for treating patients with intestinal failure. Outside the laboratory and clinic, she most enjoys running, playing golf, skiing, surfing, being near the ocean, and partnering with her husband in raising their daughter.


Julie-Ann Nguyen

Julie-Ann Nguyen, BA is a researcher in the Division of Pediatric Surgery.   



Julie-Ann’s research focus is intestinal lengthening in continuity using surgically implanted devices. She studies trends in TPN dependence in pediatric patients with short bowel syndrome. Julie-Ann also works within the Division of Clinical Anatomy and, as a result, is very interested in surgery and tissue regeneration.


Nolan Lopez

Nolan Lopez is currently completing his Bachelors Degree at Santa Clara University in Economics with a minor in Chemistry and is working as a student intern in the Dunn Laboratory.  


Nolan is currently studying the histopathology and signaling pathways associated with spring-mediated intestinal lengthening and partial obstruction models.  He is studying the effects of mechanical force on rodent and swine tissue architecture and mechanotransduction.  Specifically, he is investigating the dimension and distribution of the intestinal stem cells in the crypts.


Arshia Sazi 

Arshia Sazi is currently completing his Bachelor of Science degree in Bioengineering at Stanford University and is concurrently completing undergraduate research at the Tissue Regeneration Lab.


Arshia’s research focuses on the transcriptomics of neural circuits in colon sections experiencing force in patients with Hirschsprung disease. He aims to identify neurodegenerative mechanosensitive elements through computational analysis of human datasets and in-vivo data. Using the murine model developed by the Dunn Lab, he hopes to use the model for neural degeneration that he finds to reverse engineer a technique for neural regeneration in the enteric nervous system.

As a pre-medicine student, Arshia hopes that his work and experience in the lab can give him insights into clinical research.




Julian Muff

Julian is a Research Scholar in the Division of Pediatric Surgery, currently pursuing his MD-PhD at the University Children’s Hospital of Basel in Switzerland. He has actively engaged in research at the Dunn lab, focusing on innovative approaches to investigate tissue regeneration in the small intestine.


His research involves examining the impact of helminth-mediated tissue adaptation and partial obstruction induced changes on the tissue health and regenerative potential of the small intestine. To achieve this, Julian employs a combination of genetic mouse models, surgical techniques, and cutting-edge three-dimensional imaging. His primary interest lies in the translational potential of these findings for treating short bowel syndrome, a devastating condition that particularly affects pediatric patients.

Outside of his academic pursuits, Julian spends his free time exploring the Bay Area, whether on foot, bike, or using public transport.



Anne-Laure Thomas

Anne-Laure joined Dr. Dunn's lab in 2015 as an intern student and is now the Lab Manager.


She joined Dr. Dunn's team while completing her Masters Degree in Bioengineering in Nice, France. Upon graduating in July 2016, she started her new position as the Lab Manager. Anne-Laure's research focuses on tissue engineering and regenerative medicine. Her first project is to derive multipotent skin cells to grow neuroglial precursors for the treatment of neuromuscular dysfunction. She is also designing and 3D-printing implantable surgical devices for intestinal lengthening.

In her free time, Anne-Laure likes to be close to the ocean, enjoys attending dance classes, and exploring San Francisco.


Akanksha Sabapaty

Akanksha Sabapaty is a Visiting Instructor in the Division of Pediatric Surgery


Akanksha Sabapaty is medical graduate currently working with intestinal stem cells. Her study involves establishing intestinal enteroids in vitro from isolated human and rodent intestinal crypts. She will be introducing these enteroids into rodent models and studying its potential applications. Akanksha Sabapaty is interested in pursuing a residency in surgery.


Siavash Shariatzadeh

Siavash is a Postdoctoral Research Fellow in Dr. Dunn’s lab. He earned his MD and MPH degrees in Tehran, Iran.


During medical school, he began his research on tissue engineering and developed a pro-angiogenic placenta-derived scaffold for surgical applications. He completed his postdoctoral training at UCLA’s Surgery Department, where he specialized in the genetic risk factors of pancreatitis. In the Dunn Lab, he is investigating mechanotransduction mechanisms underlying intestine regeneration through radial and longitudinal mechanical forces. In his free time, Siavash enjoys playing cello, backgammon, and tennis. He also looks forward to playing frisbee again soon with his dog, Chilo.


Rafael Gonzalez, MD

Rafael is a board-certified pediatrician and pediatric gastroenterology fellow at Stanford Healthcare.


He earned his medical degree from the University of California, Davis and completed his pediatric residency at Valley Children’s Healthcare in Madera, California. He joined the Dunn Lab in 2022 and focuses his research on spring mediated intestinal lengthening.

Dr. Gonzalez is particularly interested in endoscopic placement of springs with the goal of developing a less invasive method to lengthen bowels. Rafael is also interested in medical device development and is applying to the Master’s of Translational Research and Applied Medicine; doing so will allow him to develop, implement, and lead the translation of research discoveries and clinical applications into biomedical innovations. In his free time, Dr. Gonzalez enjoys playing golf and spending time with his wife and his golden retriever, Hei Hei.


Pamela Emengo

Pamela Emengo, MD, serves as a Postdoctoral Research Fellow within the Department of Pediatric Surgery. She earned her MD degree from the Jacobs School of Medicine in New York and currently holds the position of general surgery resident at Mount Sinai in New York. 


Pamela's research endeavors are centered on the integration of technology, clinical, and translational methodologies to address contemporary challenges within the field of pediatric surgery. Concurrently, she is pursuing a Master's in Public Health program at the University of California, Berkeley. 

Upon completion of her dedicated research period, Pamela plans to resume her residency and subsequently pursue a pediatric surgery fellowship to further advance her knowledge in the field. 



Helene Nepomuceno, MD

Helene is a clinical and research postdoctoral fellow through the Stanford Innovations in Pediatric Surgery program. 


She received her B.S. in Biochemistry and Molecular Biology from Trinity University in San Antonio, TX where she completed her thesis on the role of tight junction proteins in the structural reorganization of epithelial cells. She received her medical degree from the University of California, Irvine School of Medicine and recently completed her residency in general surgery at Sunrise Consortium in Las Vegas, Nevada. Helene is an aspiring pediatric surgeon dedicating the next chapter of her training to further developing her skills in research and contributing to the understanding and treatment of pediatric surgical diseases. She has a background in health policy, leadership, and advocacy and looks forward to combining her interests in a career spent advocating in and out of the operating room, through policy, and through innovation aimed at improving health for the littlest of patients.





Abstracts and Presentations

Correlation of Focal Adhesion with Intestinal Crypt Fission under Mechanical Force in a Murine Model

Three-dimensionally printed surface features to anchor endoluminal spring for distraction enterogenesis

"Springs with bidirectional hooked surface features were anchored to the intestine for up to 4 weeks without migration. Bidirectional features printed on springs prevented the premature migration of endoluminal springs. These novel spring anchors allowed for their endoluminal placement without any sutures."

Spontaneous and Periodic Contractions of Murine and Human Intestinal Muscularis Cells

Associated Smooth Muscle Cell Proliferation Leads to Muscle Thickening in Intestinal Obstruction

Mechanically induced development and maturation of human intestinal organoids in vivo

"... we show that the incorporation of uniaxial strain, using compressed nitinol springs, in human intestinal organoids transplanted into the mesentery of mice induces growth and maturation of the organoids."

Double Plication for Spring-Mediated in-Continuity Intestinal Lengthening in a Porcine Model

Dr. Dubrovsky presented research done with Dr. James Dunn at the 13th Annual Academic Surgical Congress

A Novel Culture System for Adult Porcine Intestinal Crypts

A new "method [was developed that maintains] juvenile and adult porcine crypt cells long-term in culture. Porcine enteroids and spheroids can be successfully passaged and transduced by using lentiviral vectors."

Intestinal Matrix Prevents Therapeutic Ultrasound from Causing Inertial Cavitation in Tumescent Subcutaneous Tissue

Dr. James Dunn collaborated with the University of California at Los Angeles's Physics Department to find that subcutaneous tisseu campens inertial cavitation. 

Basic Fibroblast Growth Factor eluting Microspheres Enhance Distraction Enterogenesis

"Sustained release bFGF microspheres enhanced distraction enterogenesis through improved vascularity. The synergy of growth factors such as bFGF with distraction enterogenesis may yield improved results for the future treatment of patients with short bowel syndrome."

Alumni Member of the Stanford Dunn Lab

  • Adan Velasquez, MD candidate
  • Modupeola Diyaolu, MD
  • Steve (Po-Yu) Lin, PhD
  • Tommy Nguyen, MS
  • Lauren Wood, MD
  • Hadi Hosseini, PhD, Postdoctoral Fellow
  • Katherine Portelli, MD candidate
  • Jun-Beom Park, MD
  • David Shih, undergraduate student
  • Cassie (QianQian) Wang, PhD
  • Leslie Hwang, high school student
  • Shivani Singh, PhD
  • Eric Kramer, PhD, Postdoctoral Fellow
  • Jordan Taylor, MD
  • Nhan Huynh, MD
  • Fereshteh Salimi-Jazi, MD
  • Talha Rafeeqi, MD
  • Asia Smith, MD candidate
  • Kian Chen, high school student