Stanford Researchers Cure Type-1 Diabetes in Mice Using Dual Cell Transplant
In an experiment that exceeded scientists' expectations, researchers at Stanford Medicine cured type-1 diabetes in mice through a novel double-transplant method that required neither insulin injections nor immune-suppressing drugs. The breakthrough involved transplanting both pancreatic islet cells and blood stem cells from healthy donors, creating what the team calls a "hybrid immune system" that prevented the body from attacking the transplanted cells.
Type-1 diabetes differs fundamentally from type-2 in that it's an autoimmune disorder—the patient's own immune system attacks the islet cells in the pancreas that produce insulin, the hormone responsible for controlling blood-glucose levels. This makes type-1 particularly challenging to treat, as any transplant solution must address two problems simultaneously: replacing the destroyed islet cells and preventing the immune system from attacking them again.
The Stanford team achieved remarkable results. In their study, 19 out of 19 mice were prevented from developing type-1 diabetes, while 9 out of 9 mice that already suffered from the disease had it cured. For the entire six-month follow-up period, none of the treated mice required insulin injections or immunosuppressant medications.
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Start Your News Detox"The key steps in our study—which result in animals with a hybrid immune system containing cells from both the donor and the recipient—are already being used in the clinic for other conditions," said Seung Kim, MD, PhD, a multidisciplinary professor at Stanford University. "We believe this approach will be transformative for people with type 1 diabetes or other autoimmune diseases, as well as for those who need solid organ transplants."
How the Treatment Works
The researchers used a pre-transplant preparatory drug, building on methods from a previous 2022 study, to prepare the mice's immune systems before transplantation. This preparation allowed the mixture of transplanted islet cells and hematopoietic stem cells to create an immune system of mixed origin—one containing cells from both donor and recipient. This hybrid system proved capable of both accepting the transplanted islet cells and preventing the autoimmune attack that characterizes type-1 diabetes.
Dr. Judith Shizuru, a member of the study team, contributed a significant refinement to the protocol. She developed a gentler pre-treatment approach to blood stem cell transplantation, moving away from the intense radiation therapy traditionally required to clear the patient's bone marrow. Instead, her method "knocks back" the bone marrow just enough to allow donor stem cells to establish themselves—a less vigorous approach that proved successful in the mice.
Path to Human Application
While the results in mice are extraordinary, translating them to humans presents distinct challenges. Pancreatic islet cells can only be obtained from deceased donors, while blood stem cells must come from the same person receiving the transplant. The size difference between mice and humans also raises questions about how many millions of islet cells would be needed to achieve similar results in people.
Future research will focus on two key areas: developing methods to cultivate pancreatic islet cells in the laboratory using pluripotent stem cells, and finding ways to increase the survivability of transplanted islet cells. Despite these hurdles, Kim expressed optimism about the clinical potential.
"The possibility of translating these findings into humans is very exciting," Kim said. "Just like in human type 1 diabetes, the diabetes that occurs in these mice results from an immune system that spontaneously attacks the insulin-producing beta cells in pancreatic islets. We need to not only replace the islets that have been lost but also reset the recipient's immune system to prevent ongoing islet cell destruction. Creating a hybrid immune system accomplishes both goals."
The research also holds promise for other currently incurable autoimmune diseases. The same approach is being hypothesized as a potential treatment for conditions like rheumatoid arthritis and lupus, and the gentler stem cell transplantation method could eventually replace the life-threatening radiation therapy currently required for treating certain cancers, including leukemia and lymphoma.
