Scientists have shown for the first time that sperm created from embryonic
stem cells can be used to produce live offspring.
The experiment, carried out by researchers in Britain and Germany using mice,
culminated in the births of seven babies. Six of these, whose origins were owed
to sperm derived from these "multipurpose" cells, lived to adulthood, according
to a press release from the University of Newcastle on Tuesday.
In the research, a team led by professor Karim Nayernia, who was formerly
based at Georg-August University in Germany, succeeded in converting stem cells
taken from early mouse embryos into "spermatogonial stem cells" (SSCs), and then
into functioning sperm.
Nayernia, who is now professor of Stem Cell Biology at Newcastle University,
and his team were the first in the world to isolate spermatagonial stem cells.
The scientists were also able to show that some of these stem cells, called
multi-potent adult germline stem cells (maGSCs), turned into heart, muscle,
brain and other cells.
The breakthrough was reported in the academic journal Developmental Cell. The
team described how they developed a new strategy for generating mature sperm
cells in the laboratory using embryonic stem cells from mice. The researchers
then went on to test whether this sperm would function in real life, the press
release said.
The researchers implanted the sperm artificially into eggs collected from
mice, and showed that the sperm were capable of fertilizing the eggs, which
produced living offspring when implanted into surrogate mothers.
Of 210 eggs injected with the lab-reared sperm, 65 began to undergo cell
division, resulting in seven live births, with only one of the offspring failing
to reach adulthood, the researchers said.
Stem cells have the potential to develop into any tissue type in the body and
could therefore be used to develop a wide range of medical therapies.
The breakthrough will help scientists to understand more about how animals
produce sperm and the knowledge has potential implications for the treatment of
male infertility.
Nayernia was quoted as saying "spermatagonial stem cells are extremely
promising and more research is needed to establish their full potential."
From a scientific point of view, the breakthrough has been described as a
milestone in understanding how cells produce functioning
sperm.
