A reproductive research team in Chicago could have an answer to the ethical and scientific conundrums presented by the pursuit of stem-cell treatments.
That’s no small task considering it’s a question the top minds in science and bioethics have been racking their brains to solve. Scientists at the Reproductive Genetics Institute, or RGI, believe they can derive high-quality embryonic stem cells from an early embryo without killing it.
The approach would involve removing one cell from a very early embryo that has developed to about eight cells (called a morula), and deriving stem cells from that single cell. The embryo would still have the potential to develop into a human if implanted into a womb. The only thing preventing the scientists from trying the process is money, said Dr. Yury Verlinsky, director of RGI.
“No problem,” Verlinsky said of the technical challenge. “I need funding. If you give me funding, I will be doing this.”
Verlinsky said he can’t be certain the technique will engender embryonic stem cells, but the prospect has greater potential than more complicated proposals recently presented by other scientists to the President’s Council on Bioethics.
He and his colleagues at RGI have become experts at a technique called pre-implantation diagnosis, which helps reproduction specialists during in vitro fertilization identify embryos that are most likely to grow into healthy babies. They take one cell, called a blastomere, from the embryo — which is not damaged by the process — and test the cell for genetic markers. The researchers say they might be able to expand that single cell into an embryonic stem-cell line.
Verlinsky and his colleagues recently published the first evidence of embryonic stem cells derived from morulae in the Dec. 6 issue of Reproductive BioMedicine Online. In this experiment, which led to eight stem-cell lines (they self-replicate indefinitely), the morulae were destroyed. But because a morula contains just eight cells, it’s not hard to imagine one cell being sufficient to derive a stem-cell line.
“Certainly there will be some technical challenges, but it’s probably nothing that cannot be worked out,” said Bruno Peault, a stem-cell researcher and professor of pediatrics and cell biology at the University of Pittsburgh. “This might be a way to do this because certainly there is no damage from harvesting only one cell.”
The researchers say deriving stem cells from morulae is a more straightforward method — and the resulting cells might be more powerful — than taking them from older embryos at the blastocyst stage (about a week old).
Embryonic stem cells have the potential to cure deadly diseases, scientists say, and many believe destroying days-old embryos to obtain cells that could save lives is morally acceptable, even imperative. Others believe embryos at any stage of development are worthy of the same protection as any human being. This impasse, and President Bush’s executive order prohibiting federal funding of embryonic stem-cell research, has led to proposals of several creative alternatives to getting embryonic stem cells without killing an embryo.
The President’s Council on Bioethics heard two proposals Dec. 3. One came from two Columbia University researchers who described the potential technique in the Journal of Clinical Investigation in November. They suggested using embryos left behind at IVF clinics that have died; they compared that technique to harvesting organs from a brain-dead person for transplantation.
The only problem is, no method exists for determining whether a stored embryo has died. The Columbia researchers suggest studying large numbers of embryos to find markers of a dead embryo.
“To determine whether everything is normal or not is technically extremely difficult,” said the University of Pittsburgh’s Peault. “It’s tremendously complicated but I don’t say it won’t be feasible.”
It’s also not certain that dead embryos would lead to viable stem cells, although evidence suggests that a fair number of dead embryos contain some normal cells.
William Hurlbut, a bioethicist at Stanford University and member of the President’s Council on Bioethics, proposed a second possibility: using cloning technology, or somatic cell nuclear transfer, to create an entity using an egg and genetically altered human tissue. This “altered nuclear transfer” would not create a human life, he said, but could produce stem cells.
What constitutes a human life, however, is not a simple matter, and only seems to get more complicated as researchers learn more about the earliest stages of life. Critics have attacked Hurlbut’s proposal as a Frankensteinian scheme to booby-trap an embryo to stop its development.
Hurlbut says that’s not true, because the entity would never be a human life, just a collection of disorganized human cells.
“The biggest objection is that I’m creating an embryo that just runs into a failure later on,” Hurlbut said. “That is a misunderstanding of what I’m proposing to do.”
But Peault pointed out that it’s possible the genetic alteration meant to prevent the entity from becoming a human life might not come into play until a few days after the cloning technique is performed. Theoretically, the entity could, and likely would, be considered a human life at that early stage by the most fundamental opponents of the technique.
The president’s council deemed both proposals potential solutions to a seemingly endless debate over when life begins. Two top stem-cell scientists want to test the technique, Hurlbut said, but the researchers did not return phone calls or e-mails asking them to confirm their interest.
All of these approaches for getting stem cells without destroying an embryo require more research, which takes time and money. But some think pursuing an ethically pure technique is a waste of effort because embryos younger than 12 days are fair game under the rules of California’s $3 billion research fund.
“This whole issue about disabling embryos and finding different ways to make embryos is a very elegant dance on the head of a pin, while the field has moved on,” said Arthur Caplan, director of the University of Pennsylvania’s Center for Bioethics. “The California funding decision has made the deliberation of the bioethics committee somewhere between irrelevant and unimportant.”
Other states that fear losing their top researchers to California are jumping on the funding bandwagon. Wisconsin’s governor recently earmarked $750 million for stem-cell research and facilities; New Jersey and several other states are also doling out cash.
Still, not all states will be so friendly toward stem-cell research, and many countries, including Austria, Spain, France, Ireland and Germany, have passed laws against taking stem cells from human embryos.
“Personally, I don’t have a problem with this, but you have to deal with the people who do have problems and actually make the laws,” Peault said. “For many countries in the world, it is still a major problem to work on stem cells.”