A laboratory at the University of North Carolina at Chapel Hill has, for the first time, isolated adult stem cells from human intestinal tissue. This achievement should provide a much-needed resource for stem cells researchers to examine the nuances of stem cell biology. Also, these new stem cells should provide stem cell researchers a new tool to treat inflammatory bowel diseases or to mitigate the side effects of chemotherapy and radiation, which often damage the gut.
Scott T. Magness, assistant professor in the departments of physiology at UNC, Chapel Hill, said, “Not having these cells to study has been a significant roadblock to research. Until now, we have not had the technology to isolate and study these stem cells – now we have the tools to start solving many of these problems.”
The study represents a leap forward for a field that for many years has had to resort to conducting experiments with mouse stem cells. While significant progress has been made using mouse models, differences in stem cell biology between mice and humans have kept researchers from investigating new therapeutics for human afflictions.
Adam Grace, a graduate student in Magness’ lab, and one of the first authors of this publication, noted, “While the information we get from mice is good foundational mechanistic data to explain how this tissue works, there are some opportunities that we might not be able to pursue until we do similar experiments with human tissue”
This study from the Magness laboratory was the first in the United States to isolate and grow single intestinal stem cells from mice. Therefore, Magness and his colleagues already had experience with the isolation and manipulation of intestinal stem cells. In their quest to isolate human intestinal stem cells, Magness and his colleagues also procured human small intestinal tissue for their experiments that had been discarded after gastric bypass surgery at UNC.
To develop their technique, Magness and others simply tried to recapitulate the technique they had developed in used to isolate mouse intestines to isolate stem cells from human intestinal stem cells. They used cell surface molecules found on in the membranes of mouse intestinal stem cells. These proteins, CD24 and CD44, were also found on the surfaces of human intestinal stem cells. Therefore, the antibodies that had been used to isolate mouse intestinal stem cells worked quite well to isolate human intestinal stem cells. Magness and his co-workers attached fluorescent tags to the stem cells and then isolated by means of fluorescence-activated cell sorting.
This technique worked so well, that Magness and his colleagues were able to not only isolated human intestinal stem cells, but also distinct types of intestinal stem cells. These two types of intestinal stem cells are either active stem cells or quiescent stem cells that are held in reserve. This is a fascinating finding, since the reserve cells can replenish the stem cell population after radiation, chemotherapy, or injury.
“Now that we have been able to do this, the next step is to carefully characterize these populations to assess their potential, said Magness. He continued: “Can we expand these cells outside the body to potentially provide a cell source for therapy? Can we use these for tissue regeneration? Or to take it to the extreme, can we genetically modify these cells to cure inborn disorders or inflammatory bowel disease? Those are some questions that we are going to explore in the future.”
Certainly more papers are forthcoming on this fascinating and important topic.