Experts from Edinburgh University have recently managed to grow human eggs in laboratory conditions. They believe this breakthrough will be able to assist in preserving the fertility of patients diagnosed with cancer at a young age, and will also help gain insight into the process by which oocytes develop.
Oocytes begin to gradually mature after puberty. As they do, in order to make fertilisation possible, they discard approximately 50% of their genetic material into a cell called a polar body. Now, after decades of work, scientists were able to replicate this process. The eggs were cultured in a special medium and exposed to growth-simulating hormones and proteins. Lab conditions such as temperatures and oxygen levels were rigorously maintained.
What does this mean in the short term?
Healthy offspring were produced from lab-grown mice eggs almost two decades ago; unfortunately, human oocytes are proving trickier. While scientists have shown it is possible, they cite several issues preventing the technique from being adopted in the immediate future.
At present, the process is very inefficient – only about 1 in every 10 eggs grown in a lab successfully matured. Another cause of concern was that the oocytes’ polar bodies were larger than normal. While researchers admit this is problematic, they remain adamant that the issues can be overcome through improvements in culture conditions and technology.
It should also be noted that as no fertilisation was attempted (the lab does not yet have the necessary permits), the viability of the eggs could not be assessed.
Despite the issues facing them, experts believe eggs grown in a lab will eventually be used to assist women who had to undergo chemo or radiotherapy during their childhood. While patients diagnosed during adulthood can have eggs or embryos cryopreserved, this is not an option for young girls, whose oocytes have not yet matured. Their only possibility at present is having ovarian tissue frozen with the hope of reimplanting it back at a later stage. Growing oocytes in a lab would provide a safer and easier alternative.