Scientists have created human sperm for the first time from stem cells.
The research, carried out at Newcastle University, might enable infertile men to have children, while provoking another ethical debate on the progress of reproductive biology.
Karim Nayernia, project leader, said the “in vitro designed” sperm produced in his laboratory looked fully mobile and functional under the microscope, though more research would be needed before IVD sperm were used to fertilise human eggs. The work might lead to a fertility treatment in five to 10 years, he said.
The scientists cultured stem cells, derived from a male embryo, with special chemicals to set them on the path towards becoming sperm. A few of the cells underwent the crucial step of meiosis, cell division, followed by growth into mobile sperm with a head, to fertilise the egg, and tail, for mobility).
Professor Nayernia, originally from Iran, started his synthetic sperm research at Georg-August University in Göttingen using mouse stem cells and adult human stem cells. He moved to Newcastle in 2006 because embryo experiments are banned in Germany.
Some of his early work led to stories about “an end to men”, enabling lesbian couples to have their own biological children without male involvement but, according to Prof Nayernia, these were based on a “misunderstanding”.
“IVD sperm can only be produced from stem cells with male [XY] chromosomes,” he said. “Stem cells with female [XX] chromosomes can be prompted to form early-stage sperm but do not progress further. This demonstrates that the genes on a Y chromosome are essential for meiosis and sperm maturation.”
While the sperm produced in Newcastle came from embryonic stem cells, Prof Nayernia said it would be more practical for fertility treatment to use the new “induced pluripotent stem cell” or iPSC technology, which produces embryo-like stem cells from skin or other adult cells. That would enable a clinic to make sperm from an infertile man that were genetically identical to him – and then use them to fertilise his partner’s egg through IVF.
Prof Nayernia hopes to announce within six months that he has made human sperm from induced pluripotent stem cells. Although the results appear in a peer-reviewed journal, Stem Cells and Development, some experts said more tests would be needed to prove that the IVD sperm were functional. “It seems unreasonable to criticise our work on the basis that we have not done more, when we never claimed to have gone beyond proof of principle,” Prof Nayernia said. “Our intention was to open up new avenues of research with these early findings.”
Although UK law allows such research, the 2008 Human Fertilisation and Embryology Act bans fertility treatment with sperm or eggs made in the lab. Evan Harris, the Liberal Democrat MP, said he was “very sad” that IVD sperm could not start clinical trials in Britain without new legislation.
Tags: iPSC technology, Professor Karim Nayernia, 2008 Human Fertilisation and Embryology Act, Stem cells, human sperm, pluripotent stem cells, fertilization, human embryo, Newcastle University, Georg-August University in Göttingen, Global Development News,