American Geriatrics Society (AGS): Annual Meeting

The potential feasibility that in vivo human intestine can be developed from pluripotent stem cells offers hope to short-bowel patients chronically dependent on parenteral nutrition. Perhaps greater than this promise is the opportunity that now exists to develop models to test human-specific intestinal diseases that are not well characterized by human in vitro culture systems or current animal models. Translational examples of this include studies to examine normal and diseased conditions involving intestinal development and common human gastrointestinal infectious diseases.

In contrast to using primary cell cultures that require human intestinal samples, Spence et al (Nature. 2011 Feb;470:105-9) described an in vitro approach for generating human intestinal tissue from pluripotent stem cells termed human intestinal organoids (HIOs). Although these in vitro HIOs have some basic intestinal functionality, this model is insufficient for investigating the broad physiologic mechanisms associated with human intestinal diseases. Taking advantage of the fact that HIOs contain both epithelium and supporting mesenchyme required for engraftment that does not exist in enteroids derived from human crypt biopsies, we recently developed an in vivo transplant model (Nature Med. 2014;20:1310-4). Within 6-8 weeks after transplantation, these structures mature and grow 100-fold larger in volume.

Histologic studies show that engrafted tissue resembles native human intestine with crypt-villus architecture, underlying laminated structures, and smooth muscle layers. Further characterization revealed proliferative cells located in the base of crypts that also expressed stem cell markers. The ability to generate in vitro enteroids from these crypts demonstrates the existence of an intestinal stem cell pool. Functionally engrafted HIOs express an active brush border, barrier function, and peptide uptake. HIOs respond to humeral physiologic factors, as we demonstrated that morphometric adaptive changes with HIOs occur following intestinal resection in the host mouse.

To completely develop a functional human intestine it must contain an enteric nervous system (ENS), have an immune component, and be exposed to luminal nutrients and microbiota. Ongoing studies have developed methods to incorporate a functional ENS derived from the same pluripotent stem cell lines used to develop HIOs. Models to transplant HIOs into the mesentery of the murine bowel have allowed the development of surgical models that expose the HIOs to both luminal nutrition and microbiota. New models involving bone marrow transplantation should provide a human immune system.

Finally, the ability to generate induced pluripotent stem cells (iPS cells) from individual patients offers the unique advantage to study patient-specific factors contributing to human intestinal disease. We believe this model will provide an exciting new opportunity to understand many complex human conditions and test new therapies. Ultimately, the ability to grow functional patient-specific intestinal tissue offers the future reality of tissue replacement without immunosuppression for patients with intestinal failure.

Dr. Helmrath is professor of surgery, director of surgical research and the intestinal rehabilitation program, and the Richard Azizkhan Chair in Pediatric Surgery at Cincinnati Children’s Hospital Medical Center. He made these remarks in a Presidential Plenary session at the 2016 Digestive Disease Week.

The potential feasibility that in vivo human intestine can be developed from pluripotent stem cells offers hope to short-bowel patients chronically dependent on parenteral nutrition. Perhaps greater than this promise is the opportunity that now exists to develop models to test human-specific intestinal diseases that are not well characterized by human in vitro culture systems or current animal models. Translational examples of this include studies to examine normal and diseased conditions involving intestinal development and common human gastrointestinal infectious diseases.

In contrast to using primary cell cultures that require human intestinal samples, Spence et al (Nature. 2011 Feb;470:105-9) described an in vitro approach for generating human intestinal tissue from pluripotent stem cells termed human intestinal organoids (HIOs). Although these in vitro HIOs have some basic intestinal functionality, this model is insufficient for investigating the broad physiologic mechanisms associated with human intestinal diseases. Taking advantage of the fact that HIOs contain both epithelium and supporting mesenchyme required for engraftment that does not exist in enteroids derived from human crypt biopsies, we recently developed an in vivo transplant model (Nature Med. 2014;20:1310-4). Within 6-8 weeks after transplantation, these structures mature and grow 100-fold larger in volume.

Histologic studies show that engrafted tissue resembles native human intestine with crypt-villus architecture, underlying laminated structures, and smooth muscle layers. Further characterization revealed proliferative cells located in the base of crypts that also expressed stem cell markers. The ability to generate in vitro enteroids from these crypts demonstrates the existence of an intestinal stem cell pool. Functionally engrafted HIOs express an active brush border, barrier function, and peptide uptake. HIOs respond to humeral physiologic factors, as we demonstrated that morphometric adaptive changes with HIOs occur following intestinal resection in the host mouse.

To completely develop a functional human intestine it must contain an enteric nervous system (ENS), have an immune component, and be exposed to luminal nutrients and microbiota. Ongoing studies have developed methods to incorporate a functional ENS derived from the same pluripotent stem cell lines used to develop HIOs. Models to transplant HIOs into the mesentery of the murine bowel have allowed the development of surgical models that expose the HIOs to both luminal nutrition and microbiota. New models involving bone marrow transplantation should provide a human immune system.

Finally, the ability to generate induced pluripotent stem cells (iPS cells) from individual patients offers the unique advantage to study patient-specific factors contributing to human intestinal disease. We believe this model will provide an exciting new opportunity to understand many complex human conditions and test new therapies. Ultimately, the ability to grow functional patient-specific intestinal tissue offers the future reality of tissue replacement without immunosuppression for patients with intestinal failure.

Dr. Helmrath is professor of surgery, director of surgical research and the intestinal rehabilitation program, and the Richard Azizkhan Chair in Pediatric Surgery at Cincinnati Children’s Hospital Medical Center. He made these remarks in a Presidential Plenary session at the 2016 Digestive Disease Week.

The potential feasibility that in vivo human intestine can be developed from pluripotent stem cells offers hope to short-bowel patients chronically dependent on parenteral nutrition. Perhaps greater than this promise is the opportunity that now exists to develop models to test human-specific intestinal diseases that are not well characterized by human in vitro culture systems or current animal models. Translational examples of this include studies to examine normal and diseased conditions involving intestinal development and common human gastrointestinal infectious diseases.

In contrast to using primary cell cultures that require human intestinal samples, Spence et al (Nature. 2011 Feb;470:105-9) described an in vitro approach for generating human intestinal tissue from pluripotent stem cells termed human intestinal organoids (HIOs). Although these in vitro HIOs have some basic intestinal functionality, this model is insufficient for investigating the broad physiologic mechanisms associated with human intestinal diseases. Taking advantage of the fact that HIOs contain both epithelium and supporting mesenchyme required for engraftment that does not exist in enteroids derived from human crypt biopsies, we recently developed an in vivo transplant model (Nature Med. 2014;20:1310-4). Within 6-8 weeks after transplantation, these structures mature and grow 100-fold larger in volume.

Histologic studies show that engrafted tissue resembles native human intestine with crypt-villus architecture, underlying laminated structures, and smooth muscle layers. Further characterization revealed proliferative cells located in the base of crypts that also expressed stem cell markers. The ability to generate in vitro enteroids from these crypts demonstrates the existence of an intestinal stem cell pool. Functionally engrafted HIOs express an active brush border, barrier function, and peptide uptake. HIOs respond to humeral physiologic factors, as we demonstrated that morphometric adaptive changes with HIOs occur following intestinal resection in the host mouse.

To completely develop a functional human intestine it must contain an enteric nervous system (ENS), have an immune component, and be exposed to luminal nutrients and microbiota. Ongoing studies have developed methods to incorporate a functional ENS derived from the same pluripotent stem cell lines used to develop HIOs. Models to transplant HIOs into the mesentery of the murine bowel have allowed the development of surgical models that expose the HIOs to both luminal nutrition and microbiota. New models involving bone marrow transplantation should provide a human immune system.

Finally, the ability to generate induced pluripotent stem cells (iPS cells) from individual patients offers the unique advantage to study patient-specific factors contributing to human intestinal disease. We believe this model will provide an exciting new opportunity to understand many complex human conditions and test new therapies. Ultimately, the ability to grow functional patient-specific intestinal tissue offers the future reality of tissue replacement without immunosuppression for patients with intestinal failure.

Dr. Helmrath is professor of surgery, director of surgical research and the intestinal rehabilitation program, and the Richard Azizkhan Chair in Pediatric Surgery at Cincinnati Children’s Hospital Medical Center. He made these remarks in a Presidential Plenary session at the 2016 Digestive Disease Week.