Tuesday, March 6, 2012

Egg maturation can help women become pregnant

There are various reasons for normal pregnancy to fail. To aid with the fertilisation process, where an egg and a sperm cell come together, scientists have developed in vitro fertilisation (IVF). With this technique, an egg and sperm cell are put together in a tube to be fertilised artificially. After that, the embryo-to-be is placed back in the uterus. It yields result similar to a normal pregnancy, though with IVF there is higher risk of multiple births. And the pregnancy technique does not always work: if a woman fails to produce fully matured egg cells, scientists are unable to fertilise it outside of the womb. However, at the University of Gothenburg a mechanism was found that aids in creating fully-fledged eggs that can be used to get pregnant. This ought to be a great help for couples that, despite IVF, cannot reproduce. 

Women are born with a large set of immature egg cells, that need to develop during life before they can be used to get pregnant. Normally, egg maturation starts around puberty, and the female body releases on average one egg per month, during a period that is called ovulation. Immature cells, known as oocytes, sit around in the ovary and wait until they receive signals that tell them to start maturing. If this process is not properly developed, a women cannot become pregnant due to lack of usable eggs. 

At the University of Gothenburg, they found a molecule that ought to aid with the maturation process. It is called CDK1, and is part of a large family of molecules. They respond to certain signals: in particular CDK1 responds to a hormone partly responsible for the cycle in which an egg cell is released each month. Without CDK1, an oocyte cannot complete the maturation process and is left in an immature state. They may receive the right signals, but they lack the molecule that transforms it into actions. That is what scientists found when they knocked out the molecule in mice. It is likely that the process is very similar in humans.

In addition to knocking out CDK1, the scientists tried to re-introduce the molecule into the ovary, and found that it restarted the egg production process. It shows that we may be able to treat females that are unable to get pregnant because they cannot produce fully-fledged egg cells. Mice are often used as a model for human fertility, but it is of course necessary to starts tests on immature human egg cells. At the University of Gothenburg, they hope to start such experiments soon. Thereafter, a suitable therapy could be developed to cure this form of infertility, rendering more women able to fulfill their wish to bear a child.

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