Stem cells coaxed to produce insulin
Advance may lead to new diabetes therapy, experts say
July 31 — Israeli researchers said they have succeeded in coaxing human embryonic stem cells into producing the hormone insulin in a key step toward creating a revolutionary treatment for type 1 diabetes.
STEM CELLS — primitive master cells — that were derived from a human embryo days after fertilization transformed with chemical prodding in a petri dish into an abundant mass of cells possessing important qualities of the cells of the pancreas that secrete insulin, the researchers said. Those cells are called islet cells, or beta cells.
The findings represent a major stride toward using embryonic stem cells to treat type 1 diabetes, also known as juvenile diabetes. The appearance of the study in Tuesday’s issue of the journal Diabetes, published by the American Diabetes Association, comes as President Bush considers whether to allow federal funding for research involving human embryonic stem cells.
Embryonic stem cells, essentially the body’s early building blocks, are known for their ability to transform into virtually every cell type. Some scientists hope to harness this quality to treat type 1 diabetes by transplanting these cells into the bodies of patients in order to create healthy islet cells to secrete and regulate insulin.
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The findings were “a necessary prerequisite for therapeutic strategies” for type 1 diabetes using stem cells, the researchers wrote. They came from the Bruce Rappaport Faculty of Medicine, Technion, Israel Institute of Technology and the Rambam Medical Center in Haifa, and were led by Suheir Assady.
Dr. Christopher Saudek, president of the American Diabetes Association and a professor of medicine at Johns Hopkins University in Baltimore, called the findings “exciting.”
“Up until this point, people have talked about the possibility that human stem cells could be made to produce insulin. But here it is being demonstrated,” Saudek said.
Type 1 diabetes, an autoimmune disease, results when the pancreas, an organ located near the stomach, produces inadequate amounts of insulin to meet the body’s needs. Insulin is a hormone necessary for cells to be able to use blood sugar, or glucose, the basic fuel for the cells in the body.
In those with the disease, the immune system attacks and destroys the pancreatic islet cells responsible for producing insulin. As a result, the pancreas stops producing insulin.
Type 1Type 2SymptomsRisk factorsPreventionTestingTreatment
Type 1 diabetes is an autoimmune disease that destroys the body's ability to produce insulin, a hormone that helps the body stash various nutrients in cells. This form of the disease, which most often develops in childhood, accounts for 5 to 10 percent of cases.
Type 2 diabetes usually develops in adulthood and is caused by either the body's inability to make enough, or to effectively use, insulin. This form of diabetes accounts for 90 to 95 percent of cases.
Women can develop a form of type 2 diabetes during pregnancy called gestational diabetes. Approximately 40 percent of women with gestational diabetes who are obese before pregnancy develop type 2 diabetes within four years.
Frequent urination
Constant sensation of thirst
Unexplained weight loss
Extreme hunger
Sudden vision changes
Tingling or numbness in the hands or feet
Extreme fatigue
Slow healing sores
Frequent infections
People are more likely to develop diabetes if they are obese or have a family history of the disorder. And as age increases, so does the risk of diabetes. In addition, certain groups are at increased risk for diabetes, including blacks, Hispanics and Native Americans.
Some cases cannot be prevented. However, maintaining a healthy weight and exercising regularly may help protect against the development of type 2 diabetes in many people.
The American Diabetes Association recommends blood glucose screenings beginning at age 45, or younger if someone has a family history of diabetes, is obese or has other risk factors.
At least a third of people with type 2 diabetes go untreated because they don’t know they have the condition. Many of these people will be diagnosed with diabetes only after they have developed serious complications, such as heart attack, kidney disease or impaired eyesight.
People with type 1 diabetes must take daily insulin shots to live and are advised to carefully watch their diets.
People with type 2 diabetes may be able to control their blood sugar through diet and exercise. Others may need to take oral diabetes medicines to lower their blood glucose levels. If this doesn't work, insulin may be necessary.
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Source: American Diabetes Association
More than 1 million Americans have type 1 diabetes, which strikes children and some adults suddenly, making them dependent on daily insulin injections to stay alive. People with the disease face complications such as heart disease, stroke, amputation, blindness and kidney failure.
The American Diabetes Association said the only way to cure type 1 diabetes is by pancreas transplantation, but there is an insufficient supply of organs. Researchers are exploring alternative sources of the insulin-producing islet cells.
The researchers said the cells created in the laboratory possessed many characteristics of the islet cells, including insulin production and release. But they acknowledged they had not shown that the cells could regulate the insulin secretion depending upon the body’s glucose levels.
“Although we have not demonstrated glucose responsiveness, we cannot conclude that the cells are glucose unresponsive,” the researchers wrote.
“You can say they have demonstrated that you can turn on the gas. What they haven’t demonstrated is that you have brakes and accelerators to control it. And that’s what you would need in a final use,” Saudek added.
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Because the federal government has never funded research involving human embryonic stem cells, the study could not have been conducted in the United States with grant money from the National Institutes of Health, the major supporter of medical research.
“This is definitely the kind of research that would be accelerated enormously if federal funds could be made available for it,” Saudek said |
