Researchers have developed a new technique for growing human ovarian follicles — the small fluid-filled sacs that give rise to mature eggs — on a bioengineered ovarian scaffold made of ovarian tissue.
These findings, titled “Towards an artificial ovary: Grafting preantral follicles on decellularized human ovarian tissue,” were presented July 2 at the 34th Annual Meeting of the European Society of Human Reproduction and Embryology in Barcelona, Spain, by Susanne Pors, the study’s co-first author.
Many treatments for cancers — including ovarian cancer — such as chemotherapy and radiation therapy often damage the ovaries and leave women infertile.
Before cancer treatment, women can currently remove and freeze their eggs to be used for in vitro fertilization (IVF) procedures, or all or part of an ovary to be reimplanted after treatment.
Each method has complications, and in the case of replanting ovarian tissue, there is a risk the tissue may contain cancerous cells, meaning the cancer could return.
Egg follicles, however, have a membrane that doesn’t allow cancer to enter, and they could still be preserved and used in the future with no risk of cancer recurrence.
Researchers at the Rigshospitalet Laboratory of Reproductive Biology in Copenhagen, Denmark, have taken a leap forward in finding a solution for this problem.
The team developed a bioengineered ovary scaffold stripped of human cells that allowed the growth of early-stage human follicles, which would eliminate the chance of cancer relapse when reintroduced in a cancer survivor.
The scaffold was developed from donated ovarian tissue — from women undergoing fertility preservation ahead of cancer treatment — which were stripped of all cells through a three-day chemical process, leaving behind only a scaffold of structural proteins.
Then the team seeded hundreds of early-stage follicles isolated from women with cancer ahead of treatment onto the ovarian scaffold in the lab, and remarkably, they were able to grow.
“This is the first time that isolated human follicles have survived in a decellularized human scaffold, and, as a proof-of-concept, it could offer a new strategy in fertility preservation without risk of malignant cell re-occurrence,” Pors said in a press release.
Transplanting this human ovarian scaffold into mice showed that it could support the survival and growth of early-stage follicles. This was conducted with human or mouse follicles, and in both cases, around 25 percent of the follicles survived for at least three weeks, while nourishing blood vessels grew around the ovary.
The researchers noted that additional studies are needed to increase recovery and survival of the follicles. In addition, development and survival of the follicles might be impaired in this scaffold due to the absence of other ovarian cells that may provide key signals for their normal development.
“This challenge must be overcome to advance the bioprosthetic ovary further,” the researchers wrote.
Although the technique is promising, it could take five to 10 years of work before it can be tested in human trials, according to Pors. For now, the team plans to optimize the scaffold and seeding procedures and to evaluate the viability and quality of the follicles for further use.
If the technique proves successful in future studies, the goal is to develop an artificial ovary made of a scaffold from the woman’s own tissue or from a donor and her own follicles (eggs).
This technique could potentially help not only cancer patients but also patients with other conditions that demand chemotherapy or radiation therapy.