Scientific Advance Worries Ethicists
Scientists discover that an unlimited supply of human oocytes can be derived from stem cells. Will it lead to an anti-aging elixir — or more embryo destruction?
Human eggs apparently now can be produced in a lab dish from stem cells derived from adult women’s ovaries.
That is the promise of groundbreaking research by Harvard Medical School professor Jonathan Tilly.
The finding raises possibilities such as a limitless supply of lab-grown human eggs for experimentation and fertilization from one woman, as well as some sort of embryonic stem cell-derived, anti-aging elixir.
Tilly’s research team at Massachusetts General Hospital’s Vincent Center for Reproductive Biology published their findings — which turn a half century of embryology orthodoxy on its head — in the March issue of Nature Medicine. The dogma that women inherit a fixed “bank account” of irreplaceable eggs at birth that dwindles until it expires in menopause has apparently been rendered obsolete by the team’s isolation of egg-producing stem cells from the ovarian tissue of adult women undergoing “sex-change” operations in Japan.
Now it is British scientists who intend to carry out the next step of research, work that cannot receive federal funding in the United States: the creation of human embryos from eggs derived from those stem cells for experimentation, freezing and destruction.
“The test of an egg is to show that it can be fertilized,” said Dr. Richard Anderson of the MRC Centre for Reproductive Health at Edinburgh University, Scotland. “We see in those initial days after fertilization, in its development, if it is really an egg that can do its business.”
Anderson and his colleague, reproductive biologist Evelyn Telfer, have been working on ripening immature human eggs from adult women in vitro. Now they are collaborating with the Harvard researchers. Anderson confirmed that they have taken preliminary steps to acquire a research license from the Human Fertility and Embryology Authority (HFEA) — the watchdog organization that grants research licenses to “fertility” clinics throughout the U.K. — to allow them to experiment on human embryos made from ovarian stem cell-derived eggs as well as from their own artificially ripened eggs. They expect to be under way within the year.
Embryology teaches that a human embryo from inception to eight weeks is an individual boy or girl with his or her own unique DNA and normal life expectancy. The Church teaches that “human life must be respected and protected absolutely from the moment of conception. From the first moment of his existence, a human being must be recognized as having the rights of a person among which is the inviolable right of every innocent being to life” (Catechism, 2270).
The Catechism also teaches: “It is immoral to produce human embryos intended for exploitation as disposable biological material” (2275).
The HFEA already has approved numerous experiments on human embryos, including the creation of embryos for the sole purpose of deriving stem cells, for enhancing genetic-screening abilities for in vitro fertilization (IVF) and the creation of “interspecies” embryos.
Researchers at Newcastle Upon Tyne have an HFEA research license to generate embryonic stem cells from “cloned embryos produced by transferring human cells into rabbit eggs.”
Scottish Biomedical in Glasgow was granted a research license to produce “bulk” human embryonic stem cells for drug screening. It tells drug companies that it “would be happy to clone and develop specific mutants to complete your assays.”
The HFEA declares on its website that “human embryos have special moral status (although not full human status) and should be afforded legal protection” and that it is “the role of the regulator to ensure this protection is provided.”
“I don’t think the HFEA has ever met a human-embryo research project they didn’t like,” said David Prentice, senior fellow for life sciences at the Family Research Council’s Center for Human Life and Bioethics in Washington, D.C. “All this is, essentially, is experimenting with human beings.”
Prentice adds that such a license to create human embryos is “predicated on destroying them after two weeks.” The HFEA currently restricts human embryonic experimentation to 14 days.
An egg that can do the business of being fertilized is not necessarily safe for IVF, confirmed Anderson. “Implantation of these embryos into women seeking children is a long way off.”
But embryo researcher Tilly is flush with the possibilities from his discovery of ovarian stem cells — from bottomless egg banks to youth-restoring ovarian stem-cell transplants. When maintained outside the body, he told Nature Video, the cells “are more than happy to make eggs on their own. And if we can guide that process correctly, I think it opens up the chance that some time in the future we might get to the point of having an unlimited source of human eggs — that a woman could come in, have a small biopsy taken from her ovary for us to retrieve these cells, and once we get these cells out, we can take 100 of them and make a million of them.”
But what purpose could a million human eggs in a laboratory serve?
None good, thinks Father Alfred Cioffi of the National Catholic Bioethics Center. “There is one word for this: eugenics. Europe is reverting to the blinding fever that led to the Second World War.”
Even researcher Anderson sees the import. “It’s scary, isn’t it?” he said.
It raises the specter of a “New Eve” in a new era of asexual reproduction and in research: one woman progenitor with one gene pool.
But for Tilly, who has received funding from the American Foundation for Aging Research, the bountiful stock of human eggs is less exciting than what he has called the “grander golden chalice” of the anti-aging potential of these cells: Theoretically, ovarian stem cells might be engaged to coax aging human ovaries into functioning as younger ones, not necessarily for reproduction, but for the health benefits that attend fertility.
Interestingly, some of Tilly’s earlier research showed that bone marrow or blood cell transplants from adult fertile mice could restore fertility in mice rendered infertile by chemotherapy. Several studies have supported the findings and raise the possibility that the ovarian stem cells Tilly has isolated may even originate in bone marrow, just like scientists have shown that sperm-generating cells are in bone marrow, as are liver, blood and other stem cells.
And that raises the possibility of research bypassing the creation of human embryos altogether, the Family Research Council’s Prentice points out. Ethical therapies using adult stem cells have proven far more effective and have advanced far more quickly than those based on embryonic stem cells.
But Anderson dismissed the bone-marrow research as “quite a bit of conjecture,” and the tide of research, for now, is in the direction of mass embryo growth and destruction.
writes from Scotland.
- May 6-19, 2012