Mythical OSCs

One reason that I try to keep up to date with scientific publications re: insufficient ovaries etc. is to keep an eye out for anything from a particular research group. Last month something was published from this group, from the lab of Jonathan Tilly. Not a research paper, but an application for a patent (1). This isn’t too surprising; applications of commercial research discoveries need to be patented before being published elsewhere. And like it or not, new technologies that help infertile couples are commercial in nature (even if a research group does not intend to make money off their discovery it’s a good idea to secure a patent rather than someone else doing so).

Why am I curious about the activities of J. Tilly’s lab? Because they are the main research group (in the world) investigating whether it is possible to create new human eggs. That is probably overstating and over-simplifying the matter but it’s true enough to say that this group have been ‘hunting for OSCs’ for quite a few years now. What is an OSC? It stands for Oogonial Stem Cell (Tilly’s term). An oogonium is the type of cell that develops to form an egg (more correctly: oocyte or ovum, depending on developmental stage), so an OSC would be a stem cell that produces eggs, theoretically. But whereas our bodies contain stem cells to renew various cells in our bodies (most notably our blood) certain types of cells are thought to be not renewed in adult humans. For instance, brain cell renewal, while a nice idea, remains to be unproven.

Similarly, women are told that they are ‘born with all the eggs she will ever produce’. This is because current dogma states that the formation of eggs (actually oocytes) form in a growing female embryo during the mother’s pregnancy. The number of oocytes in any ovary actually peaks before the female baby is even born. This means we lose ‘eggs’ from our ovaries before we even join the world. That’s OK, as the number left remaining when the female child is born is enough to supply at least 3 decades of fertility. At least, this estimate of cell numbers is what the dogma (born with all your eggs) is based upon (I’d like to write a separate post on this calculation some time if I get around to it!). This is just one of the reasons why the idea of egg stem cells/OSCs seems so radical, there just doesn’t seem to be a need for them in adult women.

Of course I’d like to believe that they exist, so that rather than a depleted egg basket, I can think of my ovaries as a production line that needs a good service and then can be switched back on. This is not the process that Tilly et al. are claiming in their patent application, however. Instead, the patent is protecting the idea of using the mitochondria from the OSCs to boost other egg cells. This is wise seeing as a patent to produce human eggs skirts right along the controversial edge of what is ethically and legally patentable (I am no expert in patent law, but in Australian patent law at least, you cannot patent ‘human beings, and the biological processes for their generation’).

So the whole thing is very controversial, do these cells, with the desired ability to produce viable eggs really exist? Hopefully a peer-reviewed scientific article will follow the publication of this patent application, and then we will get to hear some of the appraisals (negative or otherwise) from those in the field that really know about this sort of thing! In the meantime, human OSCs remain mythical.

(1) US20150353887 A1 Compositions and Methods for Autologous Germline Mitochondrial Energy Transfer


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