Japanese researchers successfully create ova from IPS stem cells

OSAKA -- Japanese researchers have succeeded in creating ova from artificially derived multipurpose stem cells and using the ova to produce mice offspring through in vitro fertilization for the first time in the world, Kyodo News reported.

The achievement, announced in the online edition of U.S. magazine Science on Friday Japan time, was made by a team of researchers led by Kyoto University professor Michinori Saito.

Saito's group reported last year that it had successfully generated sperm from induced pluripotent stem (IPS) cells. The team cultivated IPS cells generated from fibroblasts of female mouse fetuses and generated cells close to a group of multipotent cells that can grow into any type of body tissue. By stimulating the pluripotent cells, the researchers developed germ cells, the forerunners of sperms and eggs.

They then created ovaries by cultivating the germ cells and female gonadal somatic cells, which determine sex, in a test tube. About four weeks after transplanting the ovaries into female mice, the researchers obtained immature eggs and later matured them in vitro.

The group fertilized the eggs in vitro with normal sperm and placed them in female mice, which later gave birth to both male and female mice that were physically unimpaired. The researchers further produced offspring of the mice and normal mice.

The group's breakthrough is expected to contribute to the study of infertility treatment and the elucidation of biogenetic mechanisms, but it is also feared to pose ethical problems as it could lead to the creation of life by humans, the report said.