Doctors may be one step closer to using stem cells to cure diabetes, according to a new study by researchers at the stem cell engineering company Novacell, Inc. in San Diego who report that they managed to convert human embryonic stem cells into insulin-producing cells.
Insulin is the chemical produced in the pancreas that allows the body to regulate blood-sugar levels — and it is precisely the substance that many of those with diabetes lack.
The researchers, who reported their findings in the journal Nature Biotechnology, found that when they injected these human cells into diabetic mice, the treatment alleviated diabetes in the rodents.
According to Dr. Emmanuel Baetge, primary study investigator and chief scientific officer at Novocell, Inc., the new technique used by his team will provide doctors with a bulk supply of clean, uncontaminated insulin-secreting cells for use in diabetes patients.
"This is a much more controlled process, and you basically are sure of getting the same quality of cell every time you do the implant," Baetge explained.
"Currently, a patient would have to wait and wait for a cadaver organ to become available, and even then there is a high risk of the cells from that organ being infected or contaminated," he said. "If we instead use embryonic stem cells then we can also make unlimited numbers of these cells and have an unlimited source that we can stockpile and have available whenever a patient is ready for it."
Stem cell experts not directly involved with the research agreed that it represents an exciting advancement.
"Theoretically, an infinite number of insulin-producing cells can be generated [using this technique]," said Dr. Curt Freed, director of the Neurotransplantation Program for Parkinson's Disease at the University of Colorado School of Medicine.
Scientists derive human embryonic stem cells from human embryos or human fetal tissue. Because stem cells have the potential to grow into any one of the body's more than 200 cell types, diabetes researchers have been searching for decades for a way to grow stem cells into insulin-producing cells — which, in those with diabetes, are destroyed by the patient's own immune system.
The only similar treatment currently in use for diabetes involves injecting patients with pancreatic islet cells — the cells in the pancreas that secrete insulin and other hormones. These are usually harvested from cadavers.
However, any time a new cell is introduced into the body, our immune system treats it as any other foreign invader and attempts to reject it.
Thus, patients receiving islet cell transplants are required to also receive medications that reduce their immune response to prevent rejection of the cells. As a result, less than 8 percent of islet cell transplants performed before last year were successful, according to the National Institutes of Health (NIH).
With this new method, scientists were able to grow insulin-producing cells in mice after about one to three months.
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.