A HUMAN ovary grown in the lab from slivers of ovarian tissue has been able to turn an immature egg into one that is ready to be fertilised.
Cancer treatment can destroy women鈥檚 eggs so artificial ovaries could give them many more chances of conceiving. Currently, only mature eggs are taken and frozen before treatment, but if eggs could be matured outside the body, lots of immature eggs could be stored instead. Researchers, too, could use an artificial ovary to test if potential toxins affect maturing eggs.
To create the artificial ovary and Stephan Krotz at the Women and Infants Hospital in Providence, Rhode Island, and their colleagues, started with theca cells, which form the outer coating of the follicle that holds the egg and produces a precursor to oestrogen. They got their cells from ovaries that had been removed from young women for other reasons. A gel mould shaped like a honeycomb was seeded with theca cells, which grew into a structure 2 millimetres wide.
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From the fluid surrounding eggs of another set of women undergoing IVF the team extracted granulosa cells, which produce the hormone oestradiol and help eggs to mature. They used a mould to form them into spherical clumps, which they placed into cavities in the honeycomb.
Next they took a human egg that was about one week shy of ovulation and placed it into the structure along with follicle-stimulating hormone, which helps egg growth but is not released in the ovaries. The egg took just 72 hours to develop to the point where it could be fertilised: at this point it had developed a 鈥減olar body鈥�, a small structure only produced once an egg is mature. The researchers reported their findings on 2 May at a meeting of the in New Hampshire.
鈥淭he egg took just 72 hours to develop in the artificial ovary to the point where it could be fertilised鈥�
The next step will be to see if the ovary can mature even younger eggs, known as primordial cells, which women have in their thousands. 鈥淲e鈥檙e hoping to take eggs that are very immature and mature them,鈥� says Carson. Krotz believes this could be done in 10 days, compared with the 280 or more days it would take in a woman鈥檚 body. Eggs seem to mature faster outside the body, which may be because the artificial ovary lacks factors produced by the body that inhibit the process.
