Researchers at the Massachusetts General Hospital have used stem cells to bio-engineer small intestine segments. The team implanted these inside rats and found they were capable of delivering nutrients to the bloodstream.
This breakthrough, reported in Nature Communications, could help many patients struggling with serious gastrointestinal diseases where part of the small intestine has to be removed. This is referred to as short bowel syndrome. The study used induced pluripotent stem cells (iPSCs) and showed that these cells can be used to create complex structures like intestine segments.
“In this study we have been able to bridge the gap between differentiation of single cells – driving stem cells to become a specific cell type – and the generation of tissue that shows a higher level of function – in this instance vascular perfusion and nutrient absorption,” said senior author Dr Harald Ott in a statement. “While previous studies have reported successful differentiation of organoids – millimeter-small units of tissue – from iPSCs, we describe a technology that enables these smaller units of tissue to form larger-scale grafts that someday could be used as implanted replacement organs.”
The approach the team took is not easy. These bioengineered intestine segments have to have an extra-cellular structure which is then filled with cells that can take in nutrients and connect to blood vessels so that said nutrients can then be transported to the rest of the body.
The structure was obtained by collecting a segment of rat intestine which was then “decellularized”, a technique used to strip the living cells from a donor organ. The team then repopulated this organ scaffolding with cells, first constructing the blood vessels and then covering them in cells capable of absorbing nutrients. The whole segment was put together in a matter of weeks.
“The next steps will be to further mature these grafts and to scale the construct to a human size, so that someday we may be able to provide a more accessible alternative to small bowel transplantation for patients with short bowel syndrome – ideally growing ‘on-demand’ patient-specific grafts that would not require immunosuppressive drugs,” Dr Ott explained.
Removal of part of the small intestine is often necessary to treat conditions like Crohn’s disease. The syndrome can be controlled by specific diets but often patients need to rely on intravenous nutrition. Hence, the ability to construct small intestine segments could be life-changing for many people.