Researchers in Barcelona have cured type I diabetes in dogs using gene therapy. A group at the Center for Animal Biotechnology and Genetic Therapy eliminated diabetes in canines with a single injection of viral vectors carrying two genes. Previously, the same group showed a similar treatment was effective in mice, but this is the first demonstration of a cure in large animals.
Diabetics are unable to properly metabolize sugar present in the blood and, since the body's cells require sugar to make energy, this deficiency disrupts many physiological systems causing the disease. Type I diabetes appears to be caused by an autoimmune reaction where an individual's own immune system attacks and kills the cells in the pancreas that make insulin--the hormone that enables the cells to take up sugar. It is not known what causes the autoimmune response. However, the result is a chronic lifelong condition in which sufferers need to frequently inject themselves with insulin to regulate their metabolism.
The cure these researchers developed involves using DNA from a virus to insert two genes into muscle cells in the dog's rear legs. One gene produces insulin, and the other makes glucokinase, which is the protein that regulates the amount of insulin produced based on the level of sugar in the blood. The viral DNA preparation containing the genes was simply injected into the muscles. Afterwards, blood sugar levels in the animals rapidly normalized and remained so for a period of over 4 years, so the cure appears permanent.
The results offer hope that this sort of treatment would work for people with type I diabetes. Very similar techniques have been used experimentally to introduce genes into humans to correct other diseases. However, a different approach would likely be required to treat the more common type 2 diabetes which is caused by insulin resistance rather than insulin production.
You can read the press release about the study on EurekaAlert.