For decades, diabetes researchers have been searching for ways to replace the insulin-producing cells of the pancreas that are destroyed by a patient’s own immune system. Now it appears that this may be possible.
Diabetes is characterized by abnormally high levels of the sugar glucose in the bloodstream. This excess glucose is responsible for most of the complications of diabetes, which include blindness, kidney failure, heart disease, stroke, neuropathy, and amputations. Type 1 diabetes, also known as juvenile-onset diabetes, typically affects children and young adults. Diabetes develops when the body’s immune system sees its own cells as foreign and attacks and destroys them. As a result, the cells of the pancreas, which normally produce insulin, are destroyed. In the absence of insulin, glucose cannot enter the cell and glucose accumulates in the blood. Type 2 diabetes, also called adult-onset diabetes, tends to affect older, sedentary, and overweight individuals with a family history of diabetes. Type 2 diabetes occurs when the body cannot use insulin effectively. This is called insulin resistance and the result is the same as with type 1 diabetes—a build up of glucose in the blood.
In April 2009, it was reported by US and Brazilian researchers that, 23 people, mostly boys and young men, were treated with stem cell therapy at a single centre in Brazil within six weeks of a new diagnosis of type 1 diabetes. They had their own blood stem cells removed and re-implanted through intravenous injection.
After the transplant, 20 of the 23 patients became insulin-free for at least a few months or even years. Twelve of them stayed free of insulin for an average of 31 months and eight patients had periods ranging from six to 47 months in which they were free from insulin. One patient was free of daily insulin for more than four years before needing insulin shots, according to the report in the Journal of the American Medical Association.
Scientists throughout the world believe that stem cell research, especially embryonic stem cell research, holds great promise in the search for a cure for type 1 diabetes as well as provide a powerful tool for controlling type 2 diabetes.
The new findings are “very encouraging,” says Dr. Richard K. Burt, associate professor of medicine at Northwestern University’s Feinberg School of Medicine, who presented the findings at a Washington press briefing. Still, he said, more study is needed before it’s known whether the treatment truly alters the course of the disease.
“I never use the word ‘cure,'” says Dr. Burt, who is also chief of the Division of Immunotherapy and Autoimmune Diseases at Northwestern Memorial Hospital in Chicago, Illinois. “We just have to wait and see.”
Two years ago, Dr. Burt and colleagues showed that 14 of 15 patients (who were also included in the new study) treated this way were able to go without insulin injections for one to 35 months, but it wasn’t clear if this was due to closer medical follow-up and lifestyle changes. In the new study, the researchers measured a protein that suggested the patients did indeed have insulin-producing beta cells, which are typically destroyed by the autoimmune disease.
The stem cell transplant procedure can be risky. After harvesting stem cells from blood samples, the patient is given chemotherapy to suppress the immune system. Then the stem cells are returned to the patient through intravenous injection. Transplanting a person’s own stem cells may “reset” the body’s immune system. This may allow the insulin-producing beta cells in the pancreas to either mend themselves or regenerate. The greatest risk is that a patient will die of an infection, Dr Burt says. While there were no deaths in the study, two patients developed pneumonia and three patients had problems with endocrine function and nine developed sperm deficiency.
In a related editorial, Dr Christopher D Saudek, of Johns Hopkins University School of Medicine in Baltimore, Maryland, noted that there isn’t likely to be a cure for type 1 or type 2 diabetes any time soon. For now, he said, patients need to use all the therapies that are currently available. “A great deal of the morbidity and reduced quality of life among patients with diabetes, as well as substantial societal expense, could be avoided or reduced by taking full advantage of therapies available today,” he wrote .
Professor Alan Trounson, a biologist and President of the California Institute for Regenerative Medicine (CIRM) $3 billion stem cell agency, has highlighted research that has transformed human embryonic stem cells into insulin-producing cells to treat diabetes in mice. He says the technique could work equally with humans. “I do think we’ll get a cure to diabetes,” he said. “We’ve got a lot of work to do because diabetes itself is a complex disease. It’s got an auto-immunity component, it’s got a cell replacement. I think it will happen. We’ll use stem cells to do that. I’m sure of that.”