A Quebec team has found what appears to be the cause of poor-quality embryos in mice. They cautioned that the human applications for the research are a long way off.
Researchers at the Centre hospitalier de l’Université de Montréal have made a discovery in laboratory mice that has the potential — should further research bear this out — to one day be used to reduce the number of miscarriages in women following in vitro fertilization.
A team led by Dr. Greg FitzHarris has found what appears to be the cause of poor-quality embryos in mice. What’s more, the researchers observed that if they treated those embryos with a relatively simple drug called proTAME, they were able to improve the quality of the embryos.
The implications for human fertility would be far-reaching, suggested Dr. Jacques Kadoch, medical director of the Clinique de procréation assistée du CHUM.
It’s estimated that one out of six Canadian couples experiences infertility, and many resort to IVF. The procedure involves growing embryos in an incubator for transfer to the woman’s uterus.
“With the latest technology, a woman has one out of two chances of becoming pregnant after the transfer of an embryo,” Kadoch explained.
“When it doesn’t work, it’s either because the embryo was of poor quality or the uterus is of poor quality. With Greg’s research, he’s trying to improve the quality of the embryo to improve the chances of a pregnancy following in vitro fertilization.”
About half of IVF embryos contain cells with an abnormal number of chromosomes. These are known as mosaic embryos, and it’s believed that they can cause a miscarriage. Thus, if a way is found to improve the quality of IVF embryos, doctors would succeed in reducing the number of miscarriages following IVF.
“To know that with mice, at least, we’re able to increase by 50 per cent the number of embryos for transfer thanks to this new treatment is very encouraging,” Kadoch added. “Greg is pursuing something that is very original and that could be interesting clinically, but it’s not for tomorrow.”
He predicted that human treatment to improve the quality of IVF embryos is perhaps 10 to 15 years into the future.
FitzHarris and his colleagues identified a defect in a mechanism called the “spindle checkpoint” that is responsible for cells in the embryo containing an abnormal number of chromosomes. To test their hypothesis, they treated the spindle checkpoint with proTAME and notice a 50-per-cent drop in those chromosomal errors.
FitzHarris’s next step in his research is to show that, in fact, the treatment can lead to more healthy pregnancies in lab mice. He also cautioned that the human applications for this research are a long way off.
“What the field really wants to be able to do is to have the best possible embryos to reduce the chances that a pregnancy will lead to a miscarriage,” FitzHarris said. “The challenge is to pick the best embryo to transfer back into the woman to try and get her pregnant.”
The findings were published Thursday in the journal Current Biology. The scientists involved work at the Research Institute of the CHUM.