Scientists create ‘miracle mice’ that can regenerate organs
Web posted at: 8/28/2005 2:52:58
Source ::: The Times
London: Scientists have created a "miracle mouse" that can regenerate
amputated limbs or badly damaged organs, making it able to recover
from injuries that would kill or permanently disable normal animals.

The experimental animal is unique among mammals in its ability to
regrow its heart, toes, joints and tail.

The researchers have also found that when cells from the test mouse
are injected into ordinary mice, they too acquire the ability to
regenerate.

The discoveries raise the prospect that humans could one day be given
the ability to regenerate lost or damaged organs, opening up a new era
in medicine.

Details of the research will be presented next week at a scientific
conference on ageing, Strategies for Engineered Negligible Senescence,
at Cambridge University. Ellen Heber-Katz, professor of immunology at
the Wistar Institute, an American biomedical research centre, says
that the ability of mice at her laboratory to regenerate appears to be
controlled by about a dozen genes.

She is still researching their exact functions, but it seems almost
certain that humans have comparable genes. "We have experimented with
amputating or damaging several different organs, such as the heart,
toes, tail and ears, and just watched them regrow," she said. "It is
quite remarkable. The only organ that did not grow back was the brain.

"When we injected foetal liver cells taken from those animals into
ordinary mice, they too gained the power of regeneration. We found
this persisted even six months after the injection." Heber-Katz made
her discovery when she noticed that the identification holes that
scientists punch in the ears of experimental mice healed without any
signs of scarring.

The self-healing mice, from a strain known as MRL, were then subjected
to a series of surgical procedures. In one the mice had their toes
amputated — but the digits grew back, complete with joints.

In another test some of the tail was cut off but also regenerated.
Then the researchers used a cryoprobe to freeze parts of the animals'
hearts, only to see these grow back again.

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