Scientists Find Probable Treatment For Male Infertility
There may yet be hope for men who have been medically certified infertile as a potentially new approach has been found.
The new approach came from the creation of healthy offspring from genetically infertile male mice.
This was achieved by scientists at the Francis Crick Institute who ound a way to remove the extra sex chromosome to produce fertile offspring.
Now published in Science, the procedure, if it can be carried out on humans, would boost the chances of men with Klinefelter syndrome (XXY) or Double Y syndrome (XYY) that are infertile having children.
Male infertility is usually a result of the chromosome make-up of the individual. A person’s sex is determined by the X and Y chromosomes. A girl usually has two X chromosomes (XX), while a boy has one X chromosome and one Y chromosome (XY). however, in rare instances, a person might have three, instead of two, chromosomes.
This situation adversely affects the formation of mature sperm and even causes infertility in the man.
The research was done in collaboration with Kyoto University and funded by the European Research Council, the Japan Science and Technology Agency, and the Japan Society for the Promotion of Science.
“Our approach allowed us to create offspring from sterile XXY and XYY mice,” says first author Takayuki Hirota from the Francis Crick Institute. “It would be interesting to see whether the same approach could one day be used as a fertility treatment for men with three sex chromosomes.”
In a preliminary experiment, the team found that stem cells produced from fibroblasts of men with Klinefelter syndrome also lost the extra sex chromosome.
The team took small pieces of ear tissue from XXY and XYY mice, cultured them, and collected connective tissue cells known as fibroblasts. They turned the fibroblasts into stem cells and noticed that in the process, some of the cells lost the extra sex chromosome. With an existing method, they used specific chemical signals to ‘guide’ the stem cells into becoming cells that have the potential to become sperm. These cells developed into mature sperm when injected into the testes of a host mouse. The researchers then harvested these mature sperm and used them through assisted reproduction to create healthy, fertile offspring.
“Our approach allowed us to create offspring from sterile XXY and XYY mice,” says first author Takayuki Hirota from the Francis Crick Institute. “It would be interesting to see whether the same approach could one day be used as a fertility treatment for men with three sex chromosomes.”
In a preliminary experiment, the team found that stem cells produced from fibroblasts of men with Klinefelter syndrome also lost the extra sex chromosome.
Senior author James Turner, Group Leader at the Francis Crick Institute, said, “There is currently no way to make mature sperm outside of the body. In our mouse experiments we have to inject cells that have the potential to become sperm back into the testes to help them finish developing.
“But we found that this caused tumours in some of the mouse recipients. So reducing the risk of tumour formation or discovering a way to produce mature sperm in a test tube will have to be developed before we can even consider this in humans.”
