Infertility is a medical problem for many couples throughout the world. Couples are considered infertile if they engage in contraceptive free intercourse without conception for a period of 12 months for women less than 35 years of age and for 6 months for women over 35 years of age. Approximately 15% of couples are infertile and in 50% of these cases, it is due to a male medical disorder. For many years, scientists have been trying to produce viable sperm and eggs from embryonic stem cells, which could aide infertile couples in conceiving a child. This has been one of the most fundamental challenges in the field of biology. In 2009, scientists from Newcastle University had claimed to have produced functional human sperm from embryonic stem cells, but their results were disputed by several experts in the field. The paper was later retracted after the editors discovered plagiarism in the published work. Researchers from Kyoto University in Japan lead by Dr. Mitinori Saitou have successfully produced viable and functional mouse sperm from mouse embryonic stem cells. The results of their work were published online in the journal Cell. The researchers were able to produce primordial germ cells (PGCs) from embryonic stem cells that would go on to give rise to healthy viable and functional sperm cells. The PGCs were transplanted into infertile mice which were not able to produce sperm, and resulted in normal appearing sperm. The sperm that was produced was used to fertilize mouse eggs, and then the fertilized eggs were transplanted into female mice. The females produced healthy male and female offspring that were fertile and able to procreate. The authors wrote, “We demonstrate here the generation of primordial germ cell-like cells (PGCLCs) in mice with robust capacity for spermatogenesis… Continued investigations aimed at in vitro reconstitution of germ cell development, including the induction of female PGCLCs and their descendants, will be crucial for a more comprehensive understanding of germ cell biology in general, as well as for the advancement of reproductive technology and medicine”. This is a remarkable advancement and could one day produce viable and fertile organisms from the induced pluripotent stem cells that can be derived from adult skin fibroblasts. More research is needed, but this is one step closer to allowing some infertile couples conceive a child.
Katsuhiko Hayashi et al. “Reconstitution of the Mouse Germ Cell Specification Pathway in Culture by Pluripotent Stem Cells” Cell published online August 4, 2011 doi: 10.1016/j.cell.2011.06.052