[tt] Uterus on a chip for first three days of conceptus

[Hughes, James J.]

http://www.reuters.com/article/latestCrisis/idUSHKG274279

Japan scientists devise "womb" for IVF eggs

Fri Jul 27, 2007 5:06AM EDT

By Tan Ee Lyn

HONG KONG, July 27 (Reuters) - Scientists in Japan have created a "womb"
for incubating artificially fertilised eggs in their earliest days,
helping them grow nearly as fast as they would in the uterus, a
researcher said on Friday.

Currently, test-tube human embryos are kept in "microdroplets" -- a
mixture of mineral oil and culture fluid to keep them from drying out.

But that lags the superior conditions provided by the womb and
artificially fertilised embryos tend to grow a lot slower in
microdroplets compared to naturally conceived embryos.

This is not ideal because larger, faster-growing embryos are believed to
stand a better chance of survival after being reinserted back into the
mother's womb.

In the latest issue of New Scientist Magazine, researchers in Japan said
they had devised a "chip" measuring 2 mm across and 0.5 mm high, which
they said simulates more closely the conditions of a natural womb.

Fresh IVF embryos are slipped into the chips, which rest on a membrane
of cultured uterus cells. Once they are ready to attach themselves to
the uterus wall, the eggs are reinserted into the mother's womb.

"The idea is to give a more comfortable environment for the embryos...it
works like a bed for embryos," said Teruo Fujii of the University of
Tokyo's Institute of Industrial Science.

Fujii's team experimented with mouse embryos and found that those grown
in chips grew quicker than those in microdroplets.

Eighty percent of embryos held inside the chips were ready for the
uterus in 72 hours, while only 20 percent of embryos held in
microdroplets grew to that stage in the same amount of time.

"It's a large difference between the conventional method and our
device," Fujii said in a telephone interview.

"Embryos that develop fast are of higher quality ... so the artificial
uterus environment can give us a way to make embryos develop faster and
simulate a situation closer to the (womb)," he said. They hope to use
the chip for human embryos eventually.

But eggs inside female mice still had the best environment, with 90
percent of them ready for the uterus in 72 hours.