Immature sperm cells have been created from human bone marrow, it was revealed today.
The breakthrough raises the future possibility of manufacturing sperm that can be used in IVF treatment or to restore fertility to men made sterile by cancer therapy.
Such applications are still many years away, but scientists hope to grow fully formed sperm cells in as little as three years.
The research, conducted in Germany, is published today in the journal Reproduction: Gamete Biology.
A team led by Professor Karim Nayernia, from the University of Gottingen, first took bone marrow from male volunteers. From the samples, they isolated mesenchymal stem cells, which have previously been shown to grow into body tissues such as muscle.
Using a form of vitamin A, the scientists coaxed the mesenchymal cells to become primordial germ cells (PGCs)
- the first stage in the genesis of sperm. Specific genetic markers showed that some PGCs had further developed into more advanced spermatagonial stem cells.
Under normal circumstances, these cells eventually turn into mature, functional sperm that can fertilise an egg. About 3 per cent of the original bone marrow stem cells were able to reach the point of being spermatagonial cells.
PA