April 26, 2001
Scientists Report Progress on Stem Cells
Filed at 6:36 p.m. ET
WASHINGTON (AP) -- Scientists say they have turned embryonic stem cells into insulin-producing cells that may cure diabetes, while other scientists have cloned specialized neurons in research directed at a new treatment for Parkinson's disease.
The two studies, appearing Friday in the journal Science, were conducted in laboratory mice. The Bush administration continues to ban federal funding of research using human embryonic stem cells.
At the National Institutes of Health, researchers cultured stem cells from mouse embryos to form a complex that secreted insulin, potentially an important step toward a diabetes cure.
In another study, researchers at Rockefeller University and Sloan Kettering Memorial Hospital in New York created a cloned mouse embryo and then cultured its stem cells into neurons that made dopamine, a brain chemical that is missing in patients with Parkinson's disease.
Nadya Lumelsky of the National Institute of Neurological Disorders, lead author in the diabetes study, said that her team found a way, using special proteins, to make mouse embryonic stem cells grow into islet cells of the type that produce insulin, a hormone that Type 1 diabetes patients lack.
``They formed into structures that are reminiscent of pancreatic islets,'' said Lumelsky. ``They are organized in a similar fashion.''
She said that when glucose, or sugar, was added to the medium surrounding the cells, they produced small amounts of insulin, responding just as islet cells do in the pancreas.
NIH scientists are forbidden by federal law from doing the same experiment using human embryo cells, but Lumelsky said the team will test insulin-producing stem cells by putting them into mice that have diabetes. In theory, the transplanted stem cells could cure diabetes in the animals.
Dr. Robert Goldstein, chief scientific officer of the Juvenile Diabetes Research Foundation, hailed the work by Lumelsky and her team as ``an important discovery which holds great promise for patients seeking a cure for juvenile (Type 1) diabetes.''
Tony Perry, a co-author of the other stem cell paper, said that his team proved that cloning may be a new pathway toward making stem cells to treat complex diseases.
In the study, researchers used techniques like those used to clone Dolly, the famous sheep.
Perry said the researchers removed a cell from an adult mouse and extracted the genetic pattern. They then removed the nucleus from a mouse egg and replaced it with the genes from the adult mouse cell. They cultured this egg to form an embryo and make stem cells that genetically matched the original adult mouse.
These stem cells were then transformed into neurons that produce dopamine in the brain. Parkinson's disease is caused by the lack of dopamine.
``The vision behind this therapeutic cloning is to take a cell from a patient and create an unlimited supply of a specialized cell that can be used for therapy in that patient,'' said Perry. Such cells would match the cells of the patient and would not be rejected, he said.
``This was the first step in showing this kind of therapy might work,'' said Dr. Lorenz Studer of Memorial Sloan-Kettering Cancer Center and a co-author of the study.
Embryonic stem cells are among the first cells formed after conception. From these cells, all the tissues in the body evolve. Scientists believe the cells could be used to restore ailing hearts, livers and other organs.
Many people, including some members of congress, object to human embryonic stem cell studies because harvesting the stem cells kills the human embryo. Congress has banned federally funded research that kills a human embryo.
The proposed NIH guidelines get around this restriction by permitting federal funding of studies using embryonic stem cells that have been harvested by privately funded researchers.
Bush ordered that the new guidelines not be followed until after an HHS review.
The first federal funding of human embryo stem cell research was originally scheduled to be awarded this summer. |
