As an intern at COSMOS Online:
Six live mouse pups were recently born of artificial sperm grown from embryonic stem cells. The study reveals promising information about cell development that may one day be used in treating male infertility.
The study was reported in the U.S. journal Developmental Cell on Monday. According to its authors, results indicate the success of embryonic stem cells in normal fertilisation, and provide further insight into mammalian reproduction – much to the delight of the scientific community.
"The findings are incredible in the sense that it may open a door for reproductive therapies that, until now, were science fiction," said reproductive biologist Orly Lacham-Kaplan of the Monash Institute of Reproduction and Development. "It is great proof to all scientists working on this topic that we are [heading in] the right direction."
A team led by Karim Nayernia, professor of stem cell biology at the University of Newcastle, U.K., isolated stem cells from blastocysts, which are early-stage embryos only a few days old.
From these cells were extracted those that would go on to form sperm, known as spermatogonial stem cells (SSCs). The SSCs were then cultured in the laboratory, and when some developed into sperm, they were injected into female mouse eggs and grown into early-stage embryos. The embryos were transplanted into the wombs of surrogate mothers.
"This research is particularly important in helping us to understand more about spermatogenesis, the biological process in which sperm is produced," Nayernia said. "We must know this if we are to get to the root of infertility.
"If we know more about how spermatogonial stem cells turn into sperm cells, this knowledge could be translated into treatments for men who are unable to produce mature sperm, although this is several years down the line.
"For example, we could isolate a patient's spermatagonial cells using a simple testicular biopsy, encourage them in the laboratory into becoming functional sperm and transplant them back into the patient."
While hundreds of mouse eggs were injected with the artificial sperm, only 50 began to develop as embryos. A mere seven of these survived to birth, with one of the pups dying shortly afterwards. None of the remaining six pups lived a full two years - the expected lifespan of a laboratory mouse - they all had truncated lives, dying within five months.
"The latest findings highlight that these processes in the test-tube are far from perfect as the mice that were born by this process were abnormal," said Harry Moore, professor of reproductive biology at U.K.'s University of Sheffield. "We therefore have to be very cautious about using such techniques in therapies to treat men or women who are infertile due to a lack of germ stem cells until all safety aspects are resolved. This may take many years."
Clearly, more research is needed before the full potential of SSCs can be established, as Nayernia noted.
However, according to medical ethicist Anna Smajdor of the Imperial College London: "Sperm and eggs play a unique role in our understanding of kinship and parenthood, and being able to create these cells in the laboratory will pose a serious conceptual challenge for our society.
"Who is the father of offspring born from laboratory sperm? A collection of stem cells in a petrii dish? The embryo from which the cells were derived?
"The answers to these questions are not clear, but they go to the foundations of our sense of identity."
Lacham-Kaplan, who has encountered her share of opposition to her research, is of the mindset that "everyone is entitled to their opinion".
"I think that anything that is done to allow a man and a woman to have their desired child is OK, as long as it is safe and there will not be abnormalities associated with the outcome," she said – adding that she is personally opposed to reproductive cloning.
