- The Washington Times - Friday, June 21, 2002

Studies released yesterday added to growing evidence that adult stem cells were far more flexible and versatile than originally believed, raising hopes they could reduce the need for embryonic stem cell research.

The use of embryonic stem cells for therapeutic purposes has become the subject of moral and political debate in recent years.

In a televised news conference in Minneapolis, Dr. Catherine Verfaillie, director of the University of Minnesota's Stem Cell Institute, discussed studies she led that showed that bone marrow stem cells from adult mice can evolve into most, if not all, tissues of mice, after they have been injected into early-stage mouse embryos.

"This occurs with one out of every three cells. Some of the animals are 40 percent derived from the bone marrow stem cells, suggesting that the cells contribute functionally to a number of organs. This is similar to what one would expect with embryonic stem cells," said Dr. Verfaillie.

Stem cells are the raw materials out of which more specialized tissues develop in the body. Embryonic stem cells can differentiate into any type of tissue, a trait that could make them valuable in treating certain life-threatening diseases, such as Alzheimer's, diabetes and Parkinson's.

Pro-life groups oppose the use of embryonic stem cells because human embryos must be destroyed to obtain the cells. Congress is considering bills that would ban the cloning of human embryos for either reproductive or therapeutic purposes. Backers of those bills say the emphasis should be placed on finding therapeutic uses for adult stem cells.

Rep. Dave Weldon, Florida Republican, sponsor of a bill to ban all human cloning that passed the House with a 100-vote margin, hailed the Minnesota study: "This is a tremendous addition to adult stem cell research, which has already been used successfully in 45 human clinical trials, including the treatment of Parkinson's and juvenile [insulin-dependent] diabetes," Dr. Weldon, a physician, said yesterday.

"These cells have all the qualities touted of embryonic stem cells without all the ethical dilemmas," he added.

The report by Dr. Verfaillie and her research colleagues was one of two important papers on developments in stem cell research published yesterday in Nature. The second, said senior author Ronald McKay of the National Institute of Neurological Disorders and Stroke, showed that embryonic mouse stem cells can be used to treat Parkinson's disease in rats.

The stem cells were transformed into neurons in a petri dish. The neurons complete with the brain chemical dopamine were transplanted into the brains of rats that were missing dopamine-producing cells on one side of their brains. The neurons functioned normally, and the rats showed signs of recovery from Parkinson's in behavioral tests.

Of the McKay study, Dr. Weldon said: "Even today's embryonic stem cell study with rats shows that human cloning for research is not necessary and a ban on human cloning would not affect stem cell research."

In the Minnesota research published yesterday, Dr, Verfaillie and her colleagues provided evidence for the first time that adult bone marrow cells can differentiate, both in a test tube and in a living mammal, into cells of all three embryonic skin layers endoderm, ectoderm and mesoderm. It was already known embryonic stem cells could do this.

Dr. Verfaillie told reporters that cells grown from adult mouse and rat bone marrow can be cultured without aging and with active telomerase, an enzyme found in embryo stem cells that prevents aging.

In subsequent studies, Dr. Verfaillie's lab found that adult bone marrow stem cells apparently had specialized to fit in with virtually every organ where they appeared. In addition to the skin, the changed cells also showed up in the brain, the lungs, the heart, the retina, muscle, intestines, kidney and spleen.

She acknowledged it was not clear the cells were functioning normally in those sites. But she cited cases in which the cells made up 45 percent of the hearts of some animals, and the mice remained healthy. This shows the modified heart cells were evidently working fine, she said.

Dr. Verfaillie's new research comes just six months after another report that said her lab had found that certain bone marrow cells taken from adult humans can differentiate to other cell types in test tubes.

Her latest study also comes on the heels of a report by University of Florida researchers, published in the Proceedings of the National Academy of Sciences, that showed that adult rat liver stem cells can evolve into insulin-producing pancreatic cells.

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