WASHINGTON – Three leading biomedical scientists updated the President's Council on Bioethics Thursday about the promise of stem cell research while cautioning the council about the obstacles and ethical dilemmas facing this blossoming field of science.
“We're going to have an awesome power,” said John Gearhart,director of the Developmental Genetics Division,Gynecology and Obstetrics at Johns Hopkins University’s Bloomberg School of Public Health
But Gearhart said patients with diseases such as diabetes,Parkinson's or Alzheimer's should understand that clinical treatment through the use of stem cells remains years away.
Despite his optimism that scientists will eventually unravel the complexities of stem cell research,he said,right now “the more progress you make,the farther away the goal is.”
The council was formed to advise the president on ethical issues that arise from advances in biomedical science and technology,such as embryo and stem cell research,assisted reproduction and cloning.
Formed in November 2001,the council was given a two-year existence unless the president chooses to prolong its term in November. The president has not announced his intentions.
Stem cells are genetically unspecific cells that scientists can alter,causing them to become the desired type of cell. Scientists hope that,in the future,they will be able to create body tissue and organs. Scientists hope to inject these cells into damaged or diseased tissue,such an Alzheimer's victim's deteriorating brain,causing it to regenerate.
There are three sources from which scientists draw stem cells: adult tissue,in-vitro fertilized human embryos and cloned human embryos.
Some scientists,ethicists and politicians have expressed deep reservations about using stem cells from human embryos,especially cloned embryos. The most research has been conducted with adult stem cells.
David A. Prentice,a biochemist and cell biologist at Indiana State University,told the council that researchers are having difficulty identifying adult stem cells in the human body.
When they have identified such cells and injected them into damaged tissue,Prentice said there have been some positive therapeutic results,such as partially reforming tissue around the bone marrow of a damaged human spinal cord. But instead of being incorporated into the damaged tissue,the injected stem cells signaled other cells to repair the tissue.
Prentice said these results indicate that the promise of adult stem cell research may actually lie in a non-cell,signal based system.
Dr. Rudolf Jaenisch,who researches nuclear cloning at the Massachusetts Institute of Technology,agreed with Prentice that there has been significant difficulty working with adult stem cells. He said that,while adult stem cells have been used in therapeutic purposes,their application in research is limited.
Jaenisch,contrary to the opinion of President Bush and many other opponents of cloning,said he sees fewer ethical constraints with stem cell research involving cloned embryos than he does with in-vitro embryos.
When scientists extract stem cells from embryos for research,they destroy the embryos in the process,which creates the ethical dilemma.
Jaenisch said certain biological barriers in cloned embryos — due to the absence of fertilization between a sperm and an egg — would prevent them from developing into normal humans or developing into humans at all.
In-vitro embryos have the full potential to develop into normal humans,he said,giving them more value as a definite source of human life.
His argument did not sit well with Council Member Dr. William B. Hurlbut,a human biology professor at Stanford University.
Hurlbut,who described his own daughter as “handicapped,” said he did not like the idea of a human's normality determining that person's level of humanity.
“Clones have to qualify as entities of their species,” he said.
Hurlbut said he is concerned that scientists might be tempted to push a cloned embryo into further development for harvesting of organs because it will take such a long time for researchers to develop embryonic stem cells into useful tissues and organs.
Harvard law professor Lori B. Andrews told the committee on Friday that state laws regulating biomedical research vary. Some states ban embryo stem cell research completely,while others have virtually no restrictions,advertising their states as beacons for biotechnology.
The president has forbidden federal funding for research involving cloned embryos. He has also limited federal funding for stem cell research involving embryos created through in-vitro fertilization to 70 cell lines developed before August 2001.
The Senate is considering two bills that would ban both private and public funding for the cloning of fully developed humans. One of the bills would also ban cloned embryos. The House has already voted to ban all cloning.
Dr. Leon R. Kass,the council's chairman,and the rest of the council said they will likely recommend that the president push for more monitoring of biomedical research and assisted reproduction through in-vitro fertilization.
Council members said they plan to investigate the need for a regulatory board appointed by the president to oversee the safety of biomedical research.
Paul Lauritzen,professor of religious studies at John Carroll University,which is near Cleveland,told the council he has seen some research indicating that children conceived through in-vitro fertilization were twice as likely to develop serious health and organ problems. It's something,he said,that requires more attention and research.
Council Member Paul McHugh,director of the psychiatry and behavioral sciences department at Johns Hopkins University School of Medicine,said,partly in jest,that “unless the scientific community feels the villagers are going to come out with their torches and burn the laboratory down,” nothing is going to happen to limit rogue researchers.
Francis Fukuyama,professor at the Paul H. Nitze School of International Studies at Johns Hopkins,responding in kind,warned that “the peasants with the torches” aren't always rational.