11 June 2008 | Nature 453, 828-829 (2008) |
Egg shortage hits race to clone human stem cells
Researchers back bid to pay donors.
US researchers are not allowed to pay women for egg donation.AJ
PHOTO/SPLUS stem-cell researchers are calling for changes to state
laws that prohibit compensating women who donate eggs for research.
The laws, in leading stem-cell research states such as Massachusetts
and California, are crippling the promising field of `therapeutic
cloning' that could produce useful embryonic stem-cell lines for
studying various human diseases, they say.
Therapeutic cloning involves transferring the nucleus from an adult
human cell into a human egg with the intent of creating stem cells
from the resulting embryo. Such cells could potentially serve as a
therapy genetically matched to the person who donated the adult cell.
Although no one has yet derived these cells, one group has now
reported creating cloned human embryos in this way. But the procedure
uses many eggs. Researchers say that because many states do not allow
women to be paid for their egg donation, potential donors are put off
and choose lucrative fertility clinics instead.
It took Kevin Eggan and Douglas Melton, of Harvard University's Stem
Cell Institute, two years and US$100,000 in local advertising to
secure a single egg donor (see `How close, how comfortable?
their attempt to develop embryonic stem-cell lines to model diseases
such as amyotrophic lateral sclerosis. The group, which obtained
fewer than ten eggs, completed its experiments early this year, Eggan
announced last month at a meeting of the Society for the Study of
Reproduction in Kona, Hawaii. They are not yet ready to discuss
results.
Eggan says that although Harvard's highly publicized egg-donation
programme received plenty of responses, many women decided against
donating for research when they were informed that a fertility clinic
would compensate them for the same procedure. The extraordinary
efforts needed to recruit donors such as this "unique woman" would
not be required, says Eggan, if rules restricting the compensation of
donors were relaxed.
Fertility clinics in the United States are allowed to pay for eggs.
Some advertise remuneration in the tens of thousands of
dollars. "It's patently unfair," says Sam Wood, head of Stemagen, a
biotech company based in La Jolla, California, which uses eggs
leftover from fertility procedures at an associated clinic. In
January, Wood's team reported the first cloned human blastocysts.
These early-stage embryos were created from 29 egg cells retrieved
from three donors (A. J. French et al. Stem Cells 26, 485–493; 2008).
Stemagen attains the consent of both donor and recipient, but offers
no compensation beyond that offered for the reproductive egg
donation. This `uncompensated shared cycle donation', model
has "worked quite well", Wood says, but a compensation model would be
fairer to donors. "For virtually any other type of biomedical
research you are allowed to compensate fairly."
US regulations vary from state to state — New York is currently
debating its laws on egg payment. Some states allow for reimbursement
of lost wages, expenses or child care during the procedure, which can
take 60 hours, including initial screening, consultations, hormone
injection and surgical removal of oocytes. Other countries, including
the United Kingdom, allow compensation in different forms, such as
offsetting the costs of fertility treatment in return for research
material.
The US National Academy of Sciences (NAS) guidelines barring
compensation were set in part to protect poor people from being
exploited by labs that might offer large sums of money — along the
lines of rules barring compensation for organ donation. But Alta
Charo, a lawyer and bioethicist at the University of Wisconsin Law
School in Madison, who liaised with the NAS committee that set donor-
compensation guidelines in 2005, says the move was as much political
as ethical. In California, supporters of Proposition 71, which allows
funding for stem-cell and cloning research in the absence of federal
funding, adopted compensation prohibition in part, Charo claims, "to
assuage a fringe group of the women's movement" that was aligned
against the assisted-reproducti
The NAS guidelines followed the lead taken by California and some
countries to ensure that stem cells could easily cross state and
international borders. The United Kingdom, however, essentially
changed the rules two years ago. In 2006, Alison Murdoch of Newcastle
University received approval for a plan to allow couples to defray
the costs of fertility treatments if they are willing to share some
eggs for research purposes. This could create disparity in the
quality of care available to people who don't have the money to
undergo fertility treatments, says Charo, but it could also provide
access to such treatments for more people. Murdoch has so far
collected more than 100 eggs in this fashion.
Wood says that this egg-sharing workaround presents a problem; the
eggs being used for research are from older individuals, presumably
with fertility problems. Using eggs donated by women aged 20–24, he
has reportedly achieved cloning success rates near 25%.
And there are ethical concerns. Marcy Darnovsky of the Center for
Genetics and Society in Oakland, California, says that such schemes
split the doctor's duty of care three ways: between donor, fertility
patient and researchers. And the focus on compensation, she says,
distracts from concerns about risks from this one research avenue
when other avenues seem open.
Even in light of rapid advancement of induced pluripotent stem
cells — embryonic stem cell-like cells created by adding specific
genes to adult cells — research using human eggs to reprogramme the
nucleus continues, and with some success. Wood says Stemagen's work
has been advancing rapidly. Eggan's group, while waiting for fresh
eggs, showed that in principle unfertilized eggs could be obviated by
introducing a nucleus into an already fertilized egg (D. Egli et al.
Nature 447, 679–685; 2007), which might be easier to obtain.
Still, Eggan says, his group's first modest attempts with
unfertilized human eggs are more compelling. "Our results confirm,
for us, that the best way to do the experiments is with unfertilized
oocytes. That said, it doesn't seem like we're going to be getting
many of those any time soon."
http://www.nature.
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StemCells subscribers may also be interested in these sites:
Children's Neurobiological Solutions
http://www.CNSfoundation.org/
Cord Blood Registry
http://www.CordBlood.com/at.cgi?a=150123
The CNS Healing Group
http://groups.yahoo.com/group/CNS_Healing
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