July 8, 2009

Scientists Use Embryonic Stem Cells To Create Human Sperm

For the first time ever, British scientists announced on Wednesday they had created human sperm using embryonic stem cells, AFP reported.

A new technique developed by researchers led by Professor Karim Nayernia at Newcastle University and the NorthEast England Stem Cell Institute (NESCI) allows the creation of human sperm in the laboratory.

While the researchers believe the discovery could eventually help men with fertility problems, other experts are not yet convinced that fully developed sperm have been created.

Additionally, British law currently prohibits the sperm, developed from stem cells with XY chromosomes (male), from being used for fertility treatment.

But Nayernia called it an important development that would allow researchers to study in detail how sperm forms, which will lead to a better understanding of infertility in men. He also suggested the research, published in the journal Stem Cells and Development, could also help experts better determine how genetic diseases are passed on.

"This understanding could help us develop new ways to help couples suffering infertility so they can have a child which is genetically their own," he said.

The researchers acknowledged that more study would be needed to see if the so-called in-vitro derived (IVD) sperm could be used as a fertility aid.

Nayernia said he hopes that legislation would be put in place "sooner rather than later" to allow the technique to be licensed, although he said it would probably be a decade before the treatment would be fully developed.

The team essentially developed stem cells that had XY chromosomes into germline cells, which can pass their genetic material to future generations. The germline cells were then prompted to complete meiosis, or cell division, which then produced what they called fully mature and functional sperm.

Further efforts to develop cells with XX chromosomes (female) in the same way did not progress beyond early stage sperm and the researchers concluded that the genes on a Y chromosome are essential for sperm maturation.

But others in the field remain skeptical of Navernia's results.

Dr. Allen Pacey, a senior lecturer in andrology at the University of Sheffield and a sperm biologist of 20 years' experience, said he was unconvinced from the data presented in this paper that the cells produced from embryonic stem cells can be accurately called 'spermatozoa'.

After reviewing the study, he concluded: "While the cells produced may possess some of the distinctive genetic features and molecular markers seen in sperm, fully differentiated human spermatozoa have specific cellular morphology, behavior and function that are not described here."

Other experts raised certain ethical issues concerning the study.

Josephine Quintavalle from Comment on Reproductive Ethics (Corethics) told BBC News it was an "example of immoral madness".

She argued that perfectly viable human embryos had been destroyed in order to create sperm over which there would be huge questions of their healthiness and viability.

"It's taking one life in order to perhaps create another. I'm very much in favor of curing infertility but I don't think you can do whatever you like," she said.


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