The first cellular atlas of the ovary opens the door to extending fertility

A team of researchers from the University of Michigan, in USAhas created the first cell atlas of the human ovary, revealing the factors that make a follicle produce eggs and opening the way to the extension of the fertility.

The discovery, reported this Friday in the journal Science Advances, has led to a complete cellular characterization of the ovary, with the description and location of all its molecules, which has been possible thanks to the analysis of tissues from the ovaries of five human donors.

This study is part of the Human Cell Atlas project with which science aims to achieve a complete mapping of the human body to fully understand how it works and what goes wrong in diseases.

Currently, surgeons can implant previously frozen ovarian tissue to temporarily restore hormone and egg production.

The problem is that this tissue does not function for long because very few follicles (the structures that produce hormones and create eggs) survive the implant.

Now, cellular characterization of the ovary reveals that the majority of the follicles, called ‘primordial’, remain inactive and are located in the outer layer of the ovary, called the cortex.

There is a smaller proportion of follicles, called ‘functional’, that are periodically activated and migrate into the ovary, to a region known as the growth fund, where they produce eggs that are subsequently released into the fallopian tube.

Guide the creation of eggs

A relatively new technique, known as spatial transcriptomics, has made it possible to track the gene activity of cells and reveal the factors that cause a follicle to mature and produce eggs.

Knowing these factors will allow the ovarian tissue to be genetically edited to guide the development of the follicles, in such a way that this tissue works better and longer once implanted than the one that is not modified.

With this advance, a patient who has to undergo toxic medical treatments such as chemotherapy or radiotherapy could freeze ovarian tissue that can later be reimplanted.

Creating productive ovarian tissue through gene editing would open the door, according to researchers, to a longer fertility window, as well as a longer period of time in which the body would produce hormones that would help regulate the menstrual cycle and improve muscular, skeletal and cardiovascular health.

“Our ovary can even be used to create an artificial ovary that, over time, could be transplanted into the body,” explains one of the authors, Ariella Shikanov, a biomedical engineering researcher at the University of Michigan in a statement from this university.

The same scientific team is mapping other parts of the female reproductive system, such as the uterus and fallopian tubes.

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