British scientists say created sperm from stem cells
A team of British scientists claimed Wednesday to have created human
sperm using embryonic stem cells, in a medical first that they say will
lead to a better understanding of fertility.
Researchers led by Professor Karim Nayernia at Newcastle University
and the NorthEast England Stem Cell Institute (NESCI) developed a new
technique that allows the creation of human sperm in the laboratory.
They stressed that the sperm, developed from stem cells with XY
chromosomes (male), would not be used for fertility treatment, as this
is prohibited by British law and in any case is not their main interest.
"This is an important development as it will allow researchers to
study in detail how sperm forms and lead to a better understanding of
infertility in men - why it happens and what is causing it," said
Nayernia.
"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 more investigation was needed to decide whether the so-called
in-vitro derived (IVD) sperm, could be used as a fertility treatment,
for example for boys who became infertile after receiving chemotherapy
for cancer.
While such a treatment would not likely be developed for at least a
decade, Nayernia said legislation should be put in place "sooner rather
than later" to allow the technique to be licensed.
The team's work involved developing stem cells that had XY
chromosomes into germline cells - cells that can can pass their genetic
material to future generations.
These were then prompted to complete meiosis, or cell division, which
then produced "fully mature, functional sperm."
Stem cells are immature cells that can develop into different cell
types.
The scientists tried to develop cells with XX chromosomes (female) in
the same way but they did not progress beyond early stage sperm, called
spermatagonia.
The team concluded that the genes on a Y chromosome are essential for
sperm maturation.
The research, published in the journal Stem Cells and Development,
could also lead to a better understanding of how genetic diseases are
passed on. However, other scientists expressed doubt about the work.
"As a sperm biologist of 20 years' experience, I am unconvinced from
the data presented in this paper that the cells produced by Professor
Nayernia's group from embryonic stem cells can be accurately called
'spermatozoa'," said Dr Allen Pacey, senior lecturer in andrology at the
University of Sheffield.
"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, behaviour and function
that are not described here."
AFP
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