Type 1 diabetes is the ultimate form of treason: the human body turning on itself.
In one of every 800 people in the United States, the immune system attacks its own tissues and destroys cells in the pancreas that make insulin. They have type 1 diabetes.
Without insulin, sugar in the bloodstream can’t deliver needed energy to cells. Type 1 diabetes patients must inject insulin regularly to stay healthy.
City of Hope researcher Chu-Chih Shih, Ph.D., wants to see if he can throw that process into reverse and restore the pancreatic cells, which are called islet cells, so they can produce insulin again. His tools? Stem cells.
Shih recently reported in the journal Stem Cells and Development that adult stem cells found in human bone marrow can develop into cells similar to lost islet cells. Scientists could potentially use this method to restore islet cells in type 1diabetes.
Although the most common diabetes treatment is insulin injection, researchers at City of Hope are starting to transplant islet cells from donors into type 1 diabetes patients. City of Hope is one of just a few national islet cell transplantation centers to perform the procedure.
Currently, doctors transplant islet cells from those who have donated their organs after dying. However, these donor tissues are scarce; according to Shih, about 2,000 people have donated their pancreas, but millions of patients with diabetes stand to benefit from transplantation.
But if scientists could coax adult stem cells to develop into islet-like cells, they might provide a more plentiful supply of insulin-producing cells. Shih tested his strategy in mice by incubating the stem cells with transplanted human pancreas tissue.
Four months later, the transplanted cells not only survived but also produced insulin. Even more promising, Shih and colleagues found that when these cells were transplanted into laboratory mice that had type 1 diabetes, the transplant largely relieved mice of diabetic symptoms.
Better therapies are needed
Shih estimates that bringing these kinds of therapies to humans is still several years away. But these encouraging experiments could bring not only freedom from insulin injections but better control of the disease.
One problem associated with injecting insulin, Shih noted, is its precarious dosing. Too little insulin is ineffective, but injecting too much could lead to seizures or loss of consciousness. But in lab tests, the new islet-like cells responded appropriately to levels of sugar around them — just like normal islet cells.
“These experiments prove that the islets derived from the stem cell graft are as good as the islets you would purify from the pancreas,” concluded Shih.
The sweet lowdown
Previously known as “juvenile diabetes,” type 1 diabetes is most frequently seen in children, although adults are also affected. These are a few of its warning signs:
Extreme thirst and frequent urination
Sugar in the urine
Fruity or wine-like breath odor
Drowsiness or fatigue
Sudden weight loss
Information on treatment is available from the American Diabetes Association and the Juvenile Diabetes Research Foundation.