The in vitro production of gametes from stem cells has elicited the interest of the professional and common public alike in recent years; what if we could re-create gametogenesis in a dish, and find out why it sometimes fails in our patients? What if we can make oogonia and spermatogonia in vitro, and test pollutants and new drugs in large experiments, instead of relying on imperfect animal models?
Today, Professor Jacob Hanna explained in an excellent master lecture at ESHRE Session 08 the achievements made so far, and the (not so) long road ahead. Stem cells exist in two pluripotent state, named primed and naïve, and although both can differentiate in most of the cell types in the human body, naïve stem cells are a step ahead when it comes to gametogenesis. Problem is, naïve human stem cells are hard to come by. What we usually derive from the ICM of blastocyst stage embryos are those of the primed kind, and scientists have been trying to revert them to the naïve state for several years.
Different concoctions of growth factors and inhibitors have been used, and Professor Hanna laboratory have been at the forefront of this research. In very recent years, his laboratory has identified the gene SOX17 as a master regulator of the naïve state, a discovery that, as he has shown the audience this morning, allows modulating human stem cells to give rise to primordial germ cells (the precursors of gametes) in vitro in the human species.
Professor Hanna answered a few questions from the audience, and indicated that although efforts are in place to push these in vitro obtained primordial germ cells to differentiate further to mature gametes, this objective still lays ahead for now.
The session represented another great example of how basic research supports infertility knowledge, and feed the clinical medicine of tomorrow!
Rita Vassena, Member of the Executive Committee – ESHRE, 04/07/2016.