'Artificial ovary' for humans passes key milestone

Scientists have successfully supported human follicles – the precursors of egg cells – on a bioengineered ovarian 'scaffold' for the first time. The work is an important proof-of-concept, which may pave the way for developing artificial ovaries for women undergoing cancer treatment.

The Danish team took the immature egg cells showed that they could survive on a structure made from stripping ovarian tissue of all its cells, leaving behind only its extracellular matrix.

'This is the first time that isolated human follicles have survived in a decellularised human scaffold,' said Dr Susanne Pors at the Rigshospitalet Laboratory of Reproductive Biology in Copenhagen, Denmark. She presented the results at the European Society of Human Reproduction and Embryology's annual conference in Barcelona, Spain, on Monday.

Currently, fertility may be preserved in girls and women undergoing cancer treatment by removing and freezing some ovarian tissue before treatment. This can be thawed and regrafted later to restore fertility, but there is a risk that this tissue might cause the disease to recur.

'If you put the ovarian tissue back, you might be putting back tissue with cancer in it,' said Professor Nick Macklon at the University of Southampton, who was not involved in the study. He added that the work was 'a very interesting proof-of-concept likely to develop into something potentially useful'.

The decellularised scaffold was made up of a mix of the proteins and collagens left behind. The researchers took early-stage follicles from women who were having their ovarian tissue frozen in order to preserve their fertility.

The researchers then showed that these follicles could be supported by the ovarian scaffold in vitro. They also looked at the ability of the scaffolds to support both human and mouse follicles in vivo – by transplanting the scaffolds into mice.

Three weeks after transplanting these 'artificial ovaries' into the mice, they showed that both mouse and human follicles had survived and grown.

'An artificial ovary that supports close to normal development of the follicle and the egg within it would be very valuable scientifically, helping develop new tests and perhaps treatments for infertility,' said Professor Richard Anderson at the University of Edinburgh, who also was not involved in the study.

Professor Macklon said that for this technique to be used in humans, its safety will have to be shown, and that it actually works in humans. 'With the evidence they've shown, I think there's a reasonable chance it will,' he said.