Stem cell scientists create 'virgin birth' breakthrough in mice

In a world first, scientists have created customised stem cells that aren't rejected by the body from 'virgin birth' embryos.

Master cells with the ability to turn into different tissue types, embryonic stem cells are widely seen as a repair kit for the body, offering hope for treating a variety of conditions from Alzheimer's disease to stroke.

However, embryonic stem cells from someone other than the patient are likely to be rejected by the body.

Scientists from the Boston Children's Hospital believe they may have got round this by creating stem cells that are a good match for the patient's immune system.

Although their experiments were carried out in mice, they believe it offers real hope for humans.

However, British stem cell experts point out that human treatments are at least ten years away.

The research centred around a technique called parthenogenesis, or 'virgin birth,' in which eggs are tricked into starting to develop into embryos without being fertilised by sperm.

When the embryos were just a few days old, stem cells capable of turning into any tissue in the body can be extracted.

Using a variety of chemicals, the US researchers coaxed mouse eggs into starting to develop into embryos.

They then extracted stem cells, 'matched' them to the immune system of other mice and injected them into the creatures.

There, the cells turned into a variety of different types of tissue, and, importantly, were not rejected by the mice.

While other scientists have succeeded in creating virgin birth embryos and extracting stem cells, the US researchers are the first to go on to develop customised stem cells that aren't rejected by the body.

If such a technique could be perfected in humans, it would mean women could potentially be treated with stem cells generated from their own eggs.

Men would, however, be unlikely to benefit as carrying out the same procedure on sperm is much more difficult, the journal Science reports.

Researcher Dr George Daley said: 'This technique, if proven effective in humans, offers an efficient way of generating customised stem cell lines from women.

'Right now, this technique is useful for basic research, but we are hopeful that parthenogenetic cells might prove useful for therapies.

'However, we will have to demonstrate the safety and durability of cells derived from parthenogenetic embryonic stem cells before we could imagine any clinical use.'

British stem cell experts said the technique could reduce the need the use of powerful immunosuppressant drugs in stem cell transplants.

However, they cautioned that the work is still at the early stages.

Professor Anne McLaren, of Cambridge University, said: 'The approach looks promising but it would be a decade or more before results from mice can be applied to humans.'

There are also fears that removing sperm from the equation causes abnormalities in the stem cells that could increase the risk of cancer.

Others question the ethics of such research, particularly if human eggs are used to produce virgin birth embryos or parthenotes.

Josephine Quintavalle, of campaign group Comment on Reproductive Ethics, said: 'The ethical problem which has yet to be answered is, "Can you demonstrate conclusively that the living human parthenote is not a human being?"