SCIENCE PHOTO LIBRARY, FLPAJ
APANESE researchers have successfully raised
mice using stem cells that they transformed
into egg cells. Though the technique has so
far only been proven using mice, it could one day
help infertile human couples to have children
without the need for egg donors, researchers say.
The team, led by Katsuhiko Hayashi at Kyushu
University in Japan, took skin cells from the tips
of the tails of adult mice and transformed them
into induced pluripotent stem cells. These are cells
that have been genetically modified to behave like
embryonic stem cells, which are capable of
forming any adult cell type.
To coax the stem cells into growing into eggs,
the researchers treated them with growth factors
and hormones taken from mouse ovaries.
The eggs were then fertilised using established
IVF techniques, before being implanted into the
wombs of living mice. “This is the first report
of anyone being able to develop fully mature and
fertilisable eggs in a laboratory setting right
through from the earliest stages of oocyte [egg
cell] development,” said reproduction expert
Richard Anderson, from the University of
Edinburgh, who was not involved in the research.
“One day, this approach might be useful for
women who have lost their fertility at an early age,
as well as for improvements in more conventional
infertility treatments.”
The method’s far from perfect. Only 11
of the 300 embryos implanted resulted in
successful births. What’s more, many of the
artificially produced eggs showed slight
differences in gene expression from their naturally
produced counterparts, suggesting they develop
slightly differently.
The next step is for other teams to repeat the
result, perhaps in animals such as pigs or sheep,
to confirm its validity. But debate of the ethics of
using the technique in humans should begin now,
says the University of Cambridge’s Azim Surani.
“Ethically, this issue has yet to be discussed
fully by the scientists and society.
These discussions have occurred in the past,
and are continuing within the regulatory bodies,
certainly in the UK,” he said. “This indeed is the
right time to start a debate and involve the wider
public in these discussions, long before and in case
the procedure becomes feasible in humans.”
Above: Fertilised
mouse egg cells“THIS APPROACH MIGHT BE USEFUL FOR
WOMEN WHO HAVE LOST THEIR FERTILITY
AT AN EARLY AGE”
STEM CELL SCIENCE
1908
Russian biologist Alexander Maksimov coins the term
‘stem cell’, predicting the existence of cells that can
differentiate into any other specialised cells in the body.1978
Gregor Prindull and colleagues discover haematopoietic
stem cells, those that can differentiate into all kinds of blood
cells in the body, in the blood of the umbilical cord.1998
A team led by James Thomson at the University of
Wisconsin-Madison in the USA, collects pluripotent stem
cells, those that can differentiate into nearly all kinds of cells,
from a human embryo.2005
Researchers at Kingston University and the University of
Illinois discover pluripotent stem cells in umbilical cord blood.2007
Kazutoshi Takahashi and Shinya Yamanaka of Kyoto
University, as well as researchers from James Thomson’s lab,
transform human muscle cells into pluripotent stem cells.2013
Will Shu’s team in Heriot-Watt University in Scotland,
develops a 3D printer that uses pluripotent stem cells
as building blocks.