At our Los Angeles based fertility practice, the Center for Fertility and Gynecology, we stay up to date with the latest advances in science and reproductive medicine. This week has been exciting in our field with the publication of a landmark accomplishment and the announcement of the Nobel Prize in physiology/ medicine!
In terms of the publication, a research team in Japan managed to produce eggs from stem cells. To understand what this means, and how it relates to fertility treatment, we must explain a few things about eggs and stem cells.
The human supply of eggs is a limited resource. Female fetuses produce approximately 6 million eggs by the time they are 20 weeks gestation (half way through pregnancy). From that time forward, the number of eggs constantly decreases until menopause (when no eggs remain). The fact that new eggs are not produced after 20 weeks gestation and that the total supply diminishes on a daily basis means that the egg is the single most important limiting factor for human reproduction.
Stem cells are cells which have the ability to become any type of tissue in the human body. The most talked about stem cells, embryonic stem cells, are the original cells that form a human. Picture a fertilized egg that divides into two cells, then 4 cells, then eight and so-forth. Eventually, the cells begin to form specific tissues in the body like the eyes, skin, brain and bones etc. Before the cells specialize they are called stem cells. These cells are highly valued because they can replace or repair any other type of cell in the human body.
With this in mind, the publication from the team in Japan is groundbreaking because it was the first time that anyone has been able to turn stem cells into eggs. Further, the team successfully fertilized the eggs in the laboratory (IVF) and delivered healthy mouse babies from them. Considering that (mammal) eggs are such a valuable and limited product, the ability to produce new eggs represents a huge step forward in the treatment of infertility.
Now onto the Nobel prize. It was awarded to John B. Gurdon and Shinya Yamanaka "for the discovery that mature cells can be reprogrammed to become pluripotent". What that means is that these nobel laureates were able to take cells which were not stem cells and induce them to return to the stem cell stage. This is incredibly important because although embryonic stem cells are very powerful, they are taken from an embryo which is an ethically questionable action. By reprogramming non-stem cells to become stem cells, the possibility to study and work with stem cells can proceed without ethical question.
In terms of fertility treatment, these developments mean that one day we will likely be able to overcome the natural decline in fertility seen with age. A woman will no longer be hindered by diminishing egg supply because she will be able to produce new eggs from other cells in her body. Additionally, these advances could benefit same sex couples as the production of a sperm or an egg form any cell is potentially possible.
Importantly these findings are still a long way from being available at a doctor’s office. Additionally, as they have only been demonstrated in mice, the transition to humans may not be possible. However, considering the amazing steps taken thus far, I believe it is only a matter of time before stem cell research has a direct impact on fertility therapy.
If you have any questions about stem cells or anything else related to fertility, please contact us we would be happy to speak with you.