A successful experiment on mice with type 1 diabetes, which involved “reprogramming” their immune systems to stop attacks on pancreatic beta cells, may point the way to an eventual cure for the disease in humans.
The experiment, led by the City of Hope medical research center in Duarte, California, first used antibodies to kill the two kinds of cells that are involved in autoimmune attacks against insulin-producing beta cells in the pancreas. In type 1 diabetes, the cells that defend the body against bacteria, viruses, and outside intruders erroneously attack the beta cells, eventually destroying them and the body’s ability to produce insulin.
Once the defender cells were killed, the researchers transplanted bone marrow into the mice to restore the cells. The new immune cells from the marrow no longer carried the factor that made the previous cells attack the pancreas’s insulin-making beta cells. In short, the new cells left the mice’s pancreases alone.
At the same time, the researchers injected the diabetic mice with pancreas growth factor, which led to the creation of new insulin-producing beta cells. The cessation of autoimmune attacks, combined with a restored ability to produce insulin, led to a virtual cure of the mice’s disease.
Two aspects of the study give rise to high hopes for its treatment approach. First, it involved mice that had late-stage type 1 diabetes. Second, it combined cell replacement and pancreatic growth factor, two therapies that are not new but had not been combined before.
As promising as the City of Hope approach is, it will be several years before it can be used experimentally on humans. The next step will be to try the treatment on primates, which are physiologically closer to humans than mice are.
The study, funded by the Iacocca Family Foundation and private donations, was published in Science Translational Medicine.