December 13, 2001
Transplanting small-bowel cells
By Pamela Wyngate
HS News & Community Relations
Adult stem cell research may lead to great advances in science and health research, but first researchers must literally find a method to the madness. Some UW scientists are currently defining part of that stem cell research methodology-taking cells out of the body, modifying them genetically and putting them back into the body.
Stem cells are unspecialized cells that have the ability to divide and give rise to a number of different kinds of cells with very specific functions. Dr. Matthias Stelzner, associate professor of surgery, investigates transplanting stem cells from the inner lining of the small bowel-ileal stem cells-to a higher or proximal position in the gut.
“You can view ileal cells as a paradigm for cells from the proximal gut that have a special implanted trait, that is the ability to actively absorb bile acids,” explains Stelzner. “At the moment we are transplanting stem cell clusters, so we actually take stem cells with some of the connective tissue cells attached. We have shown that by doing this we are able to produce areas that have bile acid absorption capacity in the proximal bowel. We are actually able to functionally make a zone where bile acid absorption happens-where it has not happened before.”
Why shuffle cells in the gut? There are many different cells lining the human bowel. Most are capable of nutrient absorption. Cells in the distal portion of the gut have additional specific properties, such as the capacity to absorb bile acids, which are important detergent substances aiding in absorption of fat and vitamin B12-a necessary factor in the maturation of blood cells. The distal bowel’s ability to absorb bile acids and vitamin B12 may be adversely affected by inflammatory bowel disease. Patients with bile acid malabsorption will have diarrhea, an increased likelihood of developing gall stones and an increased risk of developing kidney stones.
But the majority of patients who lose this portion of the bowel, functionally or physically, actually have it surgically removed due to inflammation, scarring or obstruction.
“In some other patients, the ileum is used to make an artificial bladder when the bladder has been removed because of bladder cancer,” says Stelzner.
Currently Stelzner and his group are collaborating with the Tissue Engineering Group at Harvard. The Harvard group is engaged in trying to make an artificial small bowel. They use techniques similar to Stelzner’s group to harvest stem cells and to evaluate functional properties of the artificial small bowel. Both groups are working with an inbred rodent strain where there are no immune barriers.
According to Stelzner, in a clinical application, the immunity problem could be addressed with medications or by using bone marrow transplantation techniques to alter the response.
“Since we are at the beginning of getting down the methods to isolate the stem cells most effectively and to get optimal engraftment rates in the proximal bowel,” he says, “right now we are not so concerned with immunologic function, and we are trying to keep it simple.”
Stelzner presents “Transplantation of Ileal Mucosal Stem Cells” at the Science in Medicine lecture, Thursday, Jan. 10, at noon in A-420 Hogness Auditorium, Health Sciences Center. Everyone is welcome.
Stelzner received a M.D. magna cum laude from the University of Bonn School of Medicine in Germany in 1983. He was an intern in gastroenterology from 1983 to 1985 at the University of Düsseldorf Hospital. From 1985 to 1987 and in 1989 Stelzner trained in the general surgery residency program at the University of Cologne Hospital and from 1991 to 1995 he was a resident in general surgery at Brigham and Women’s Hospital in Boston, Mass. Stelzner was an instructor in surgery at Harvard Medical School in 1995 and 1996. He came to the UW in 1996 as an assistant professor of surgery and is also a staff surgeon at the VA Puget Sound.
