Dennis Turner's Parkinson's disease had become so severe by 1999 that he could not use his right arm. That was the year he underwent an experimental treatment with his own brain adult stem cells. "Soon after having the cells injected, my Parkinson's symptoms began to improve," Turner testified in 2004 before the U.S. Senate. "My trembling grew less and less, until to all appearances it was gone."

He also said this: "I can't say with certainty what my condition would have become if Dr. Levesque had not used my own adult stem cells to treat me. But I have no doubt that because of this treatment, I've enjoyed five years of quality life that I feared had passed me by."

Turner is not alone in benefiting from adult stem-cell therapy. Thousands of other patients have experienced relief from conditions that include leukemia, multiple sclerosis, lupus, sickle-cell anemia, and heart damage. Adult stem cells have grown new blood vessels to prevent amputation from gangrene, new corneas to restore sight, new cartilage and bone to replace those lost through accident or disease. They've prevented life-threatening problems from genetic diseases for children. Spinal cord injuries have also shown improvement; Laura Dominguez, testifying at the same hearing as Turner, told of regaining feeling and movement after treatment with her own nasal adult stem cells.

British doctors are starting trials to test bone marrow adult stem cells to treat liver disease. And a Harvard team now has FDA approval to begin patient trials for juvenile diabetes, after scientists showed in mice that adult stem cells could achieve "permanent reversal" of diabetes.

Adult stem cells have now helped patients with at least 65 different human diseases. It's real help for real patients. For embryonic stem cells the score is zero—not a single patient has benefited from embryonic stem cells. After 24 years of research with embryonic stem cells, they are still risky even for experimental animals, all too often forming tumors or misplaced tissue in rats and mice.

Why then the obsession with embryonic stem cells? One reason is the claim that only embryonic stem cells are pluripotent, meaning they have the flexibility, or plasticity, to form most or all tissues of the body. This ability to morph into virtually any tissue type would make a stem cell useful for treating a host of diseases, slipping into any organ to replace damaged or missing cells. This is certainly a characteristic of embryonic stem cells if left in the intact embryo. But scientists have not been successful at directing the same range of tissue formation from embryonic stem cells in the lab dish.

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For adult stem cells, the dogma has been that they are not as flexible, only forming the tissue from which they originated. They have been useful for decades at replacing bone marrow and forming blood, but it was thought that they were limited in forming other tissues.

Not so. Since the mid-1990s, a rapidly growing volume of scientific evidence has documented that adult stem cells possess much greater abilities than scientists imagined, and some show the same pluripotent flexibility as embryonic stem cells. Within the last four years, researchers from around the world have documented that adult stem cells from bone marrow, blood, amniotic fluid, placenta, umbilical cord blood, and nasal tissue show this same remarkable plasticity, but without the problems of tumors seen with embryonic stem cells.

A few recent examples include a Texas-U.K. team that has shown human umbilical-cord-blood stem cells can be grown in large numbers in the lab and show the same flexibility as embryonic stem cells. University of Pittsburgh scientists recently found the same for placenta stem cells. (One researcher saved his newborn's placenta because of his experiments showing that these adult stem cells were so flexible.) And several groups have shown that bone marrow stem cells also are pluripotent.

Cardiologist Douglas Losordo at Tufts University said that bone marrow "is like a repair kit. Nature provided us with these tools to repair organ damage." He also noted that "embryonic stem cells are going to fade in the rearview mirror of adult stem cells."

Hundreds of scientific studies over the last few years document that adult stem cells can repair diseased and damaged tissue. The contrast between adult stem cells and embryonic stem cells is the difference between live patients and dead mice. While the focus has been on ethically controversial embryonic stem cells, adult stem cells—which don't involve the destruction of human lives—have quietly progressed in treating human patients.

It's time the focus shifted to the real promise for treating patients—and the real successes of adult stem cells.

David A. Prentice is senior fellow for life sciences at the Family Research Council, an adjunct faculty member at Georgetown Medical School, and a founding member of Do No Harm ( He was selected by the President's Council on Bioethics to write a comprehensive review of adult stem-cell therapies.

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Related Elsewhere:

Previous articles in this series include:

Ethics Interrupted | What does it mean when even embryonic stem-cell researchers have some qualms about their work?
Stemming the Embryonic Tide | Pro-lifers face a scientific and public relations juggernaut.

The Coalition of Americans for Research Ethics collects news, commentary, public testimony, and facts about stem–cell research.

The Center for Bioethics and Human Dignity has a collection of articles by its experts on stem cells.

The President's Council on Bioethics offers reports and discussions on topics from Aging to Stem cells.

Our weekly bioethics column, Life Matters, discusses stem cells and related life ethics issues. Nigel M. de S. Cameron's latest column was "Leon Kass, a Bioethics Legend, Steps Down."

More CT articles on stem-cell research includes:

The Stem-Cell Conspiracy | The Washington Post muddles a major breakthrough in adult stem-cell research, while the U.K. marches blindly on. (Aug. 29, 2005)
Post-Election Education | Pro-lifers weigh options after Californians fund embryonic stem-cell research. (Dec. 1, 2004)
The Politics of Stem Cells | Why do some scientists and politicians insist on exploiting embryos? (Nov. 17, 2004)
It's Not About Stem Cells | Why we must clarify the debate over harvesting embryos. (A Christianity Today editorial—Sept. 29, 2004)
California's Prop. 71 Stem-Cell 'Scam' | Supporters of cloning embryos for research have $11 million to convince state voters. (Sept. 29, 2004)
The Proposition 71 Stem Cell Scam | The biotech lobby is attempting to buy a law in California, Wesley J. Smith says. (Aug. 17, 2004)
When Does Personhood Begin? | And what difference does it make? (June 18, 2004)
Cloning Report Breeds Confusion | Does it open the door to 'therapeutic cloning'? (May 13, 2004)

More articles are available on our Science & Health and Life ethics.

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