The advance comes at a time when diabetes affects more people and causes more deaths each year than breast cancer and AIDS combined, according to NIH statistics. Diabetes is the seventh leading cause of death in the United States, with nearly 200,000 deaths reported each year. The American Diabetes Association estimates that nearly 16 million people, or 5.9 percent of the U.S. population, currently have diabetes.
Because there is a constant shortage of cadaver islet cells available for transplant, many experts believe having a "stockpile" of islet cells derived from embryonic stem cells would immensely benefit a huge number of diabetes patients.
"Islet cell transplants will always be extremely limited," Freed said. "It is my understanding that the islets from the pancreases of two cadaver donors are needed to treat one diabetic person."
According to Dr. Jeffrey Bluestone, director of the University of California at San Francisco Diabetes Center and board member for Novocell, Inc., there are too few pancreases available and, such being the case, islet cell transplants are limited to those patients with "Brittle" diabetes, meaning that they have had diabetes for such a long time that they can no longer distinguish the symptoms of hypoglycemia, or low blood sugar.
"Also, the patients [receiving islet cell transplants] need to be small — usually 150 pounds or less — because of the limited number of islets that can be obtained from each cadaveric pancreas," Bluestone said. "So, in general, a greater source of islets would have a very positive effect for the many diabetics in need of transplantation."
But despite the enormous potential for this technique to free possibly millions of Americans from their diabetes, some experts remain doubtful that this technology will be available to the public any time soon.
Many diabetes and stem cell experts believe there are a number of hurdles to overcome before this technique could replace the traditional method of transplanting islet cells from cadaver organs.
Dr. Anne Peters, director of University of Southern California's Clinical Diabetes Programs, said this study fails to provide an answer for one of the most pressing issues faced by any diabetes patient receiving any form of islet cell transplantation: What guarantee would doctors have that the transplanted insulin-producing cells would not be destroyed by the body, just as the diabetic patient's own cells were?
"What would happen to these cells in that environment?" Peters said.
Also, just as with current methods of islet cell transplantation, the body will still recognize the insulin-producing cells grown from human embryonic stem cells as being foreign. Therefore, diabetes patients undergoing this new technique will still require immunosuppressant therapies, most of them for their entire lives.
Moreover, one of the biggest concerns about injecting patients with embryonic stem cells is that these cells have the potential to develop into cancerous tumors.
"The study does show that these [human embryonic stem cells] might have developed to a point where they appear to be no longer [tumor-forming]," said Dr. Bryon Petersen, associate professor in the department of pathology at the University of Florida College of Medicine. "This is a good thing, but what needs to follow is just how long will these cells stay fully differentiated — to make these cells no longer a threat to the patient's long-term health."
But despite the hurdles that scientists face, there is little doubt that these findings have opened countless doors for research on diabetes and other genetic diseases.
"This is an extraordinary breakthrough by scientists at Novocell," Freed said. "This discovery holds promise for everyone with insulin-requiring diabetes. While outcomes of clinical trials are unpredictable, these cells are likely to be tested in patients soon."