Scientists have developed a 3D-printed structure known as a scaffold that supports the development of egg-producing cells and restores ovary function in sterile mice. There is hope that this will one day lead to the development of human artificial ovaries to help cancer patients retain their ability to procreate.
For many women, cancer treatment can have a devastating impact on ovary function and fertility, sometimes leaving them unable to conceive.
In some cases, in vitro fertilisation and ovarian transplants have been hailed as major advances. Before starting treatment, some women can choose to have their ovarian tissue frozen to keep it healthy. It can be transplanted again in the future, when they decide to have children.
To date, more than 100 babies have been born around the world thanks to this technique.
However, this approach does not work for everyone. Research has shown that in the case of leukaemia patients, ovarian tissue contains cancerous cells. Transplanting frozen ovarian tissue could lead to reintroducing malignant cells in the bodies of these women. This risk is also heightened for other cancer patients, if their disease has reached metastatic stage (when it has spread throughout the body).
For this small group of patients, developing artificial ovaries from isolated follicles (the cells in the ovaries that produce the eggs) to restore normal ovary and hormonal function is seen as a priority for scientists working in the field of fertility preservation.
In the study now published in the journal Nature Communications, researchers describe a 3D-printed scaffold which aids the development of mice follicle cells.
In the past, a number of studies has already shown that hydrogel scaffolds adequately supports follicle development – and that these bioprosthetic ovaries transplanted in mice results in live births.
The originality of this study lies not in its findings – which are very similar to what has been published previously – but in its method. It is the first time that scientists use a 3D-printing technology to create the scaffold that supports the development and survival of isolated mice follicles.
The resulting bioprosthetic ovary restored the animals' fertility, and resulted in the birth of healthy litters of mouse pups.
Next, the researchers would like to test this system in other animal models – such as primates or sheep. However, we are still a long way away from clinical applications in humans.
"Clinically, the goal of such research is to develop artificial ovaries to help some cancer patients, such as women with leukaemia, to retain their fertility. However, it's important to recognise that the scientists are working with mice, so their results may not be applicable to humans", Pr Marie-Madeleine Dolmans, from the department of gynaecology research at the Catholic University of Louvain (Belgium), and who was not involved with the study, told IBTimes UK.
"When it comes to ovarian cycles and fertility, humans and mice are two very different species. Female mice have ovarian cycles of about four or five days, while women have ovarian cycles of 28 days. In our lab, we have done similar research with human follicles transplanted in animal models and the results are not good at all".
Experts also note a number of technical problems. "Cancer patients freeze their ovarian tissue, and it is this frozen tissue that is then transplanted. But here the researchers work with fresh ovarian tissue to create their artificial ovary. So although the birth of healthy pups is a success, it is not possible to extrapolate to humans and to cancer patients just yet. We will need to conduct much more research", Jacques Donnez, a Professor Emeritus at the Catholic University of Louvain said.