Transplantation of blood stem cells, sometimes known as a bone marrow transplant, is usually a last-ditch attempt to save someone suffering from life-threatening blood or autoimmune disorders. That's because the radiation and chemotherapy used to wipe out a patient's immune system and allow the donated cells to grow are very toxic and can cause lasting organ damage or even death. Now researchers in the laboratories of Stanford oncologist Judith Shizuru, MD, PhD, and stem cell scientist Irving Weissman, MD, have come up with a kinder, gentler approach that, in mice, dramatically reduces the risk of death from the procedure.
For the study, which appears today in Science Translational Medicine, research associate Akanksha Chhabra, PhD, and former graduate students Aaron Ring, MD, PhD, and Kipp Weiskopf, MD, PhD, devised a kind of one-two punch to target the recipient's blood-forming stem cells for destruction. They also then purified the donor cells to ensure they are made up only of blood stem cells and not other contaminating cells that could cause graft-versus-host disease.
From our press release:
Comparing blood stem cell transplants to planting a new field of crops, Shizuru noted that the researchers not only found a safer way to clear the field for planting, but "we also used safer techniques to seed the new blood-generating cells." Currently, bone marrow transplants involve a mix of cells that includes blood stem cells as well as various immune cells from the donor, which can attack the tissue of the transplant recipient. This immune attack results in what is called graft-versus-host disease, which can damage tissues and even kill patients.
If the approach also works in humans, it could potentially be used to cure a variety of diseases and even help organ transplant recipients avoid rejection. As we explain in the release:
Once a patient's blood and immune system can safely be replaced, any disease caused by the patient's own blood and immune cells could potentially be cured by a one-time application of blood stem cell transplantation, they said. Safely replacing a patient's blood and immune cells will get rid of the cells that attack their own tissues and produce disease like rheumatoid arthritis and Type 1 diabetes.
As Weissman, who directs Stanford's Institute for Stem Cell Biology and Regenerative Medicine and the Ludwig Center for Cancer Stem Cell Research and Medicine said, "If and when this is accomplished, it will be a whole new era in disease treatment and regenerative medicine."
Previously: The inside scoop on bone marrow transplants, Bone marrow transplantation: The ultimate exercise in matchmaking and One (blood stem) cell to rule them all? Perhaps not, say Stanford researchers
Illustration by Carl Glover