Scientists have developed an artificial womb that
allows embryos to grow outside the body
Scientists have created prototypes made out of cells extracted
from women's bodies. Embryos successfully attached themselves to
the walls of these laboratory wombs and began to grow. However,
experiments had to be terminated after a few days to comply with
in-vitro fertilisation (IVF) regulations.
'We hope to create complete artificial wombs using these
techniques in a few years,' said Dr Hung-Ching Liu of Cornell
University's Centre for Reproductive Medicine and Infertility.
'Women with damaged uteruses and wombs will be able to have babies
for the first time.'
The pace of progress in the field has startled experts.
Artificial wombs could end many women's childbirth problems - but
they also raise major ethical headaches which will be debated at a
major international conference titled 'The End of Natural
Motherhood?' in Oklahoma next week.
'There are going to be real problems,' said organiser Dr Scott
Gelfand, of Oklahoma State University. 'Some feminists even say
artificial wombs mean men could eliminate women from the planet and
still perpetuate our species. That's a bit alarmist. Nevertheless,
this subject clearly raises strong feelings.'
Liu's work involves removing cells from the endometrium, the
lining of the womb. 'We have learnt how to grow these cells in the
laboratory using hormones and growth factors,' she said.
After this Liu and her colleagues grew layers of these cells on
scaffolds of biodegradable material which had been modelled into
shapes mirroring the interior of the uterus. The cells grew into
tissue and the scaffold dissolved. Then nutrients and hormones such
as oestrogen were added to the tissue.
'Finally, we took embryos left over from IVF programmes and put
these into our laboratory engineered tissue. The embryos attached
themselves to the walls of our prototype wombs and began to settle
there.'
The experiments were halted after six days. However, Liu now
plans to continue with this research and allow embryos to grow in
the artificial wombs for 14 days, the maximum permitted by IVF
legislation. 'We will then see if the embryos put down roots and
veins into our artificial wombs' walls, and see if their cells
differentiate into primitive organs and develop a primitive
placenta.'
The immediate aim of this work is to help women whose damaged
wombs prevent them from conceiving. An artificial womb would be
made from their own endometrium cells, an embryo placed inside it,
and allowed to settle and grow before the whole package is placed
back in her body.
'The new womb would be made of the woman's own cells. so there
would be no danger of organ rejection,' Liu added.
However, her research is currently limited by IVF legislation.
'The next stage will involve experiments with mice or dogs. If that
works, we shall ask to take our work beyond the 14-day limit now
imposed on such research.'
A different approach has been taken by Yoshinori Kuwabara at
Juntendo University in Tokyo. His team has removed foetuses from
goats and placed them in clear plastic tanks filled with amniotic
fluid stabilised at body temperature. In this way, Kuwabara has
kept goat foetuses alive and growing for up to 10 days by
connecting their umbilical cords to machines that pump in nutrients
and dispose of waste.
While Liu's work is aimed at helping those having difficulty
conceiving, Kuwabara's is designed to help women who suffer
miscarriages or very premature births. In this way Liu is extending
the time an embryo can exist in a laboratory before being placed in
a woman's body; Kuwabara is trying to give a foetus a safe home if
expelled too early from its natural womb.
Crucially, both believe artificial wombs capable of sustaining a
child for nine months will become reality in a few years.
'Essentially research is moving towards the same goal but from
opposite directions,' UK fertility expert Dr Simon Fishel, of Park
Hospital, Nottingham, said. 'Getting them to meet in the middle
will not be easy, however. There are so many critical stages of
pregnancy, and so many factors to get right. Nevertheless, this
work is very exciting.'
It also has serious ethical implications, as Gelfand pointed
out. 'For a start, there is the issue of abortion. A woman is
usually allowed to have one on the grounds she wants to get rid of
something alien inside her own body.
'At present, this means killing the foetus. But if artificial
wombs are developed, the foetus could be placed in one, and the
woman told she has to look after it once it has developed into a
child.'
In addition, if combined with cloning technology, artificial
wombs raise the prospect that gay couples could give 'birth' to
their own children. 'This would no doubt horrify right-wingers,
while the implications for abortion law might well please them,' he
added.
Gelfand also warned that artificial wombs could have unexpected
consequences for working women and health insurance. 'They would
mean that women would no longer need maternity leave - which
employers could become increasingly reluctant to give.
'It may also turn out that artificial wombs provide safer
environments than natural wombs which can be invaded by drugs and
alcohol from a mother's body. Health insurance companies could
actually insist that women opt for the artificial way.
'Certainly, this is going to raise a lot of tricky
problems.'
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source:
http://www.guardian.co.uk/world/2002/feb/10/medicalscience.research
