Stem cell technique spares embryo
Stem cell technique spares embryo
By Nicholas Wade
Copyright by The New York Times
Published: August 23, 2006
Biologists have developed a technique for establishing colonies of human embryonic stem cells from a early human embryo without killing it. This method, if confirmed in other laboratories, would seem to remove the principal objection to the research, that it involves destruction of a human embryo.
"There is no rational reason left to oppose this research," said Dr. Robert Lanza, vice president of Advanced Cell Technology and leader of a team that reported the new method in an article in the Wednesday edition of Nature.
But critics of human embryonic stem cell research raised other objections, such as the possible risk to the embryo and the in vitro fertilization procedure itself in which embryos are generated from a couple's egg and sperm.
The new technique would be performed on the two-day old embryo, after the fertilized egg has divided into eight cells, known as blastomeres. In fertility clinics, where the embryo is available outside the mother in the normal course of in vitro fertilization, one of these blastomeres can be removed for diagnostic tests, such as for Down's syndrome, and the embryo, now with seven cells, can be implanted in the mother if no defect is found. Many such embryos have grown into apparently healthy babies over the ten years or so the diagnostic tests have been used.
Up to now, human embryonic stem cells have been derived at a later stage of development when the embryo consists of about 150 cells. Harvesting these cells kills the embryo, a principal objection of those who oppose the research.
Last year, Lanza reported that embryonic stem cell cultures could be derived from the blastomeres of mice, a finding others have confirmed. He now says the same can be done with human blastomeres. Although he used discarded human embryos in his experiments, he said that anyone who wished to derive human embryonic stem cells without destroying an embryo could use a blastomere removed for the test, called pre-implantation genetic diagnosis.
"By growing the biopsied cell overnight, the resulting cells could be used for both PGD and the generation of stem cells without affecting the subsequent chances of having a child," he said.
Ronald Green, an ethicist at Dartmouth College and an adviser to Advanced Cell Technology, said he hoped the new method "provides a way of ending the impasse about federal funding for this research." He said he believed the method should be seen as compatible with the Dickey-Wicker amendment, the longstanding congressional veto on using federal funds for any research in which a human embryo is destroyed or exposed to undue risk.
Dr. James Battey, head of the stem cell task force at the National Institutes of Health, said it was not immediately clear if the new method would be compatible with the congressional restriction, since removal of a blastomere subjects the embryo to some risk, but that embryos on whom the test was performed seemed to be as healthy as all other babies born by in vitro fertilization.
President George W. Bush allowed federal funding for research on human embryonic stem cells, provided they were established before Aug. 9, 2001. Although that might seem to rule out any new cell lines derived from blastomeres, Battey said it was not clear if that would be the case since the embryo is not destroyed, and that he would seek guidance on the point.
Critics, however, have a range of objections to the research. The Catholic bishops, in particular, oppose both in vitro fertilization and preimplantation genetic diagnosis, and therefore still object to the research even though the cells would be derived from an embryo brought to term.
Richard Doerflinger, deputy director for pro-life activities at the U.S. Conference of Catholic Bishops, said the church opposed in vitro fertilization because of the high death rate of embryos in IVF clinics and because divorcing procreation from the act of love made the embryo seem "more a product of manufacture than a gift." Asked if he meant the parents of an IVF child would love it less, Doerflinger said he was referring to the clinic staff.
By Nicholas Wade
Copyright by The New York Times
Published: August 23, 2006
Biologists have developed a technique for establishing colonies of human embryonic stem cells from a early human embryo without killing it. This method, if confirmed in other laboratories, would seem to remove the principal objection to the research, that it involves destruction of a human embryo.
"There is no rational reason left to oppose this research," said Dr. Robert Lanza, vice president of Advanced Cell Technology and leader of a team that reported the new method in an article in the Wednesday edition of Nature.
But critics of human embryonic stem cell research raised other objections, such as the possible risk to the embryo and the in vitro fertilization procedure itself in which embryos are generated from a couple's egg and sperm.
The new technique would be performed on the two-day old embryo, after the fertilized egg has divided into eight cells, known as blastomeres. In fertility clinics, where the embryo is available outside the mother in the normal course of in vitro fertilization, one of these blastomeres can be removed for diagnostic tests, such as for Down's syndrome, and the embryo, now with seven cells, can be implanted in the mother if no defect is found. Many such embryos have grown into apparently healthy babies over the ten years or so the diagnostic tests have been used.
Up to now, human embryonic stem cells have been derived at a later stage of development when the embryo consists of about 150 cells. Harvesting these cells kills the embryo, a principal objection of those who oppose the research.
Last year, Lanza reported that embryonic stem cell cultures could be derived from the blastomeres of mice, a finding others have confirmed. He now says the same can be done with human blastomeres. Although he used discarded human embryos in his experiments, he said that anyone who wished to derive human embryonic stem cells without destroying an embryo could use a blastomere removed for the test, called pre-implantation genetic diagnosis.
"By growing the biopsied cell overnight, the resulting cells could be used for both PGD and the generation of stem cells without affecting the subsequent chances of having a child," he said.
Ronald Green, an ethicist at Dartmouth College and an adviser to Advanced Cell Technology, said he hoped the new method "provides a way of ending the impasse about federal funding for this research." He said he believed the method should be seen as compatible with the Dickey-Wicker amendment, the longstanding congressional veto on using federal funds for any research in which a human embryo is destroyed or exposed to undue risk.
Dr. James Battey, head of the stem cell task force at the National Institutes of Health, said it was not immediately clear if the new method would be compatible with the congressional restriction, since removal of a blastomere subjects the embryo to some risk, but that embryos on whom the test was performed seemed to be as healthy as all other babies born by in vitro fertilization.
President George W. Bush allowed federal funding for research on human embryonic stem cells, provided they were established before Aug. 9, 2001. Although that might seem to rule out any new cell lines derived from blastomeres, Battey said it was not clear if that would be the case since the embryo is not destroyed, and that he would seek guidance on the point.
Critics, however, have a range of objections to the research. The Catholic bishops, in particular, oppose both in vitro fertilization and preimplantation genetic diagnosis, and therefore still object to the research even though the cells would be derived from an embryo brought to term.
Richard Doerflinger, deputy director for pro-life activities at the U.S. Conference of Catholic Bishops, said the church opposed in vitro fertilization because of the high death rate of embryos in IVF clinics and because divorcing procreation from the act of love made the embryo seem "more a product of manufacture than a gift." Asked if he meant the parents of an IVF child would love it less, Doerflinger said he was referring to the clinic staff.
posted by Carlos T Mock at 6:45 AM
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