Stem cell breakthrough could spell end of infertility
Stem cell breakthrough could spell end of infertility
Fertile sperm are rare in men with an extra sex chromosome Dennis Kunkle Microscopy SPL
18 Agosto, 2017, 10:41
Scientists have developed a new approach to overcome a major cause of genetic infertility - sex chromosome disorders.
Most people are born with two sex chromosomes-girls with two X chromosomes, and boys with an X and a Y chromosome.
"Abnormalities of sex chromosomes are the most common genetic cause of infertility and include conditions such as Turners syndrome, where a female has only one X chromosome (XO) and Klinefelter syndrome where a male has an extra X chromosome (XXY)", Joyce Harper, Professor of Human Genetics and Embryology at University College London, who was not involved with the research, explained.
The team took fragments of ear tissue from XXY and XYY mice and cultured them. However, about 1 in 500 boys are born with one extra chromosome.
The researchers had already found that making stem cells from the fibroblasts of men with Klinefelter syndrome (XXY) gets rid of the extra sex chromosome.
If the findings can be safely transferred into humans, it might eventually be possible for men with Klinefelter syndrome or Double Y syndrome (XYY) that are infertile to have children through assisted reproduction using this technique, the researchers said. Indeed, reprogramming cells carrying a third sex chromosome led to the loss of the extra chromosome in mice as well as in human cells. They were then able to collect fibroblasts - connective tissue cells. When these cells were then coaxed into forming sperm cells and used to fertilise eggs, 50 to 60 per cent of the resulting pregnancies led to live births. They collected the mature sperm and used assisted reproduction to create healthy, fertile offspring.
"There is now no way to make mature sperm outside of the body", said senior author James Turner, in a statement. 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. Reducing the risk of tumor formation, he added, "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".
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