Membranes from the amnion – which makes up the amniotic sac that surrounds and
protects an embryo in the uterus – could in the future serve as a source for
human eggs and eventually eliminate the purchase of ova by women unable to get
pregnant.
This first-ever discovery was made by researchers at the
Technion-Israel Institute of Technology and was just published in the latest
online issue of Reproductive Biology and Endocrinology. The article is titled
“Human amniotic epithelial cells differentiate into cells expressing germ cell
specific markers when cultured in medium containing serum substitute
supplement.”
Prof. Eliezer Shalev, head of the Technion’s Rappaport
Faculty of Medicine and a leading obstetrician/gynecologist at the Emek Medical
Center in Afula, worked on the discovery with doctoral student Ayelet Evron and
Dr. Shulamit Goldman.
The amnion, part of the placenta, is routinely
thrown away after a woman gives birth. Years ago it was collected after birth by
cosmetics companies that claimed it helped make women look younger, “but this
was shown to be nonsense, so they are now thrown into the garbage,” Shalev
said.
The cells of the amniotic membrane are created during a very early
stage in the life of the embryo – about eight days after conception – and
preserve the plasticity of its embryonic cells before they differentiate. The
researchers found that these cells have the ability to differentiate into those
expressing specific markers of germ cells that produce the ova. Germ cells are
the biological route for genetic transmission from one generation to the
next.
The researchers wrote that “germ cell development has been
difficult to study in vivo [in the body] because important early events occur
after implantation.” This difficulty is most evident in humans when ethical
issues are considered.
“There is still a lot of research work to do. The
amniotic membrane’s cells look like ova and express genes characteristic of
eggs,” Shalev told The Jerusalem Post.
“It’s like the natural
situation. The eggs in the fetus will remain this way until the baby who
is born reaches sexual development, which in a girl means starting
menstruation. To turn into ova, the cells need the conditions that
adolescent girls have – proteins or hormones surrounding the
ovary.”
Additional research replicating the conditions in the adolescent
must somehow be produced by adding proteins or hormones to produce human eggs,
said Shalev.
“This could take a year or 10 or 15 years, but we discovered
the principle,” he said. “It is too early to know – but when it is done
successfully, women who do not produce healthy ova or any at all could use them
to become pregnant. These could be donated to older woman, and there would be
ethical problems, but it would probably be used mostly for women who entered
premature menopause.”
“This will eventually bring about the end of ova
sales, but it will take time.”
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