Thursday September 16 2010
Researchers hope the technique could help women having chemotherapy to conceive
An artificial ovary “can mature human eggs” outside the body, according to The Daily Telegraph. The newspaper said that an ovary-like structure, constructed in a laboratory from donated ovarian cells, could be used to mature egg cells extracted from cancer patients whose chemotherapy has made them infertile.
These experimental artificial ovaries may eventually be used to help female chemotherapy patients conceive. However, at this time there are further challenges to overcome before the technique can be used for this purpose. That said, this research is important and opens up a number of avenues for research into fertility and assisted reproduction.
The next steps for this technique will be to verify that the matured egg cells are of similar quality to naturally matured eggs and that they can be fertilised. More studies with clinical outcomes such as successful fertilisation or pregnancy using eggs grown with this technique will be needed to understand the technique’s true impact.
Where did the story come from?
The study was carried out in the US by researchers from the Women and Infants’ Hospital, Brown University, Rhode Island. It was funded by the Division of Reproductive Endocrinology and Infertility at the hospital and by a grant from the Rhode Island Science and Technology Council. The study was published in the peer-reviewed Journal of Assisted Reproduction and Genetics.
The study was reported by The Daily Telegraph and Daily Mail. Both papers reported it accurately, emphasising its potential use for women about to undergo chemotherapy. The Telegraph also included expert commentary which challenges the idea that it represents a “real” artificial ovary.
What kind of research was this?
This research paper is a technical description of a laboratory study that developed an innovation in the field of assisted reproduction. The researchers set out to create a three-dimensional artificial structure that could act as an “artificial ovary” and mature human oocytes (immature egg cells).
When oocytes mature, an early or primordial follicle (a ball of cells consisting of non-reproductive cells) goes through various developmental phases to eventually become a pre-ovulatory follicle. Within this follicle, the oocyte develops into a fully mature egg, which is released during ovulation. This oocyte maturation process normally occurs within the ovaries.
One side effect of chemotherapy drugs is that they can harm fertility. Currently, if women who are going to have chemotherapy wish to store eggs for later use, only mature eggs are collected. However, it may only be possible to collect a limited number of mature eggs before they start chemotherapy.
This research looked at whether early follicles containing immature egg cells could be collected and matured outside the body in an artificial ovary. The technique of letting ovarian follicles mature outside the body is called in vitro maturation (IVM). It is hoped the mature eggs produced in this way could be used for in vitro fertilisation (IVF). IVM could produce a greater number of mature eggs than could be collected before chemotherapy. The researchers reported that, so far, the use of IVM to produce eggs that can be fertilised and produce live offspring has only been successfully achieved in mice. Up until now, IVM for human oocytes has only had limited success.
What did the research involve?
In this research, an ovary-like structure was grown in a laboratory using ovarian follicle cells collected from women of normal childbearing age. This structure was implanted with follicles, which were observed for over 72 hours.
The researchers first collected human ovarian tissue from women who had had their ovaries removed for reasons other than cancer. From this tissue, they extracted the cells which would form the foundations for their artificial ovaries, called theca cells.
A second type of non-egg cell called the granulosa cell, which produces female sex hormones and growth factors that help a developing egg cell, was also obtained. These granulosa cells came from oocytes obtained in IVF procedures. The granulosa and theca cells were then placed in a synthetic gel mould that allowed them to form a tiny honeycomb-shaped synthetic structure.
Finally, the researchers took early follicles containing immature oocytes, also obtained from the women having their ovaries removed. These were then inserted into the holes in this honeycomb structure and cultured (grown in the laboratory). The researchers cultured the structures for up to 72 hours and monitored them to see if they were still “living”. They also looked to see if the oocytes showed signs of maturing or developing further.
What were the basic results?
The researchers showed that the structural cells from the donated ovarian tissue arranged themselves into “complex cell spheres”, which remained viable for one week. Seventy-two hours after the follicular cells were introduced to the artificial human ovary construction, the theca cells completely surrounded these developing follicles, in a process similar to normal maturation.
The artificial ovary structure was able to help the immature eggs develop into their fully mature stage, the point at which they would normally be released into the womb for fertilisation.
How did the researchers interpret the results?
The researchers concluded that an artificial human ovary can be created with self-assembled human cells and used for in vitro maturation and future oocyte toxicology studies.
The researchers say their discovery could help thousands of women with cancer who become infertile due to chemotherapy treatment. They propose that women about to undergo chemotherapy could have their immature eggs frozen, and later matured using the artificial ovary if the women wanted to have children.
This is an interesting study in which the researchers clearly described their innovative technique of in vitro maturation.
Some further issues need to be addressed before this technique is ready for use in women about to undergo chemotherapy. For example, regulation of follicular maturation will need to be better understood to be able to control when the eggs are matured and released. This knowledge might then allow the researchers to encourage a follicle to hold on to its egg until it is ready to be released. There is also a need for further studies to confirm that the mature eggs produced in this way are normal and capable of being fertilised and developing in the usual way.
This is novel and engaging research, but there are some important challenges to overcome before artificial ovaries can be used to help women conceive after chemotherapy.