Researchers Used Gene Therapy to Cure Diabetes in Dogs
What is the problem and what is known about it so far?
Type 1 diabetes irreversibly destroys the insulin-producing beta cells in the pancreas. People with the disease must replace the lost insulin by injection or pump for the rest of their lives. A controversial medical approach called gene therapy—which after some recent successes is gaining interest—involves viruses inserting genes into cells where they start producing proteins, such as insulin, to counteract disease.
Why did the researchers do this particular study?
Gene therapy has the potential to reverse diabetes by introducing the gene for insulin into non-beta cells, offering an alternate route for insulin production. For safety, the researchers wanted to test the method on dogs before attempting it in humans.
Who was studied?
The study included five beagles.
How was the study done?
Researchers gave the dogs a version of type 1 diabetes by obliterating their beta cells with a drug. Then, using viral vectors, they inserted the gene for insulin and the gene for glucokinase (an enzyme that attaches a phosphate molecule to glucose) into the dogs' muscles. Glucokinase, and the phosphorylated glucose it produces, acted as a glucose sensor, telling the muscle cells how much insulin to dispense into the blood based on the current glucose levels.
What did the researchers find?
The dogs maintained normal blood glucose levels without episodes of low blood glucose throughout the four-year study.
What were the limitations of the study?
The type of diabetes that the laboratory dogs had is not the same as type 1 diabetes, so the outcomes may be different. Also, gene therapy remains risky for humans. It has the potential to trigger the development of tumors if the gene is inserted into the genome at the wrong place. More research is needed before the treatment can be tested in people.
What are the implications of the study?
The findings suggest that gene therapy has the potential to help people with type 1 diabetes, as well as diabetic pets, regulate blood glucose levels in the long term.