"Miracle mice" can grow back lost limbs

[Moogy]

http://www.timesonline.co.uk/article...754008,00.html

The Sunday Times - Britain

August 28, 2005

'Miracle mouse' can grow back lost limbs
Jonathan Leake, Science Editor


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. A similar phenomenon was observed when the optic nerve was severed and the liver partially destroyed.

Heber-Katz will describe some of her findings at the Cambridge conference and plans to publish her results in a research paper. “We have found that the MRL mouse seems to have a higher rate of cell division,” she said. “Its cells live and die faster and get replaced faster. That seems to be linked to the ability to regenerate.”

The researchers suspect that the same genes could confer greater longevity and are measuring the animals’ survival rate. The mice are, however, only 18 months old and the normal lifespan is two years so it is too early to reach conclusions.

Scientists have long known that less complex creatures have an impressive ability to regenerate. Many fish and amphibians can regrow internal organs or even whole limbs.

Humans can regenerate their liver provided at least a quarter remains intact, as well as their blood and outer skin, but no other organs regrow.

This is probably because, although most mammalian cells start off with the potential to develop into any cell type, they soon become very specialised. This allows mammals to develop more complex brains and bodies but deprives them of the power of regeneration.

By contrast, if a newt loses a limb then cells around the injury revert back into so-called stem cells. These can develop into whatever types of cell are needed, including bone, skin or nerves.

[esupin]

Insane. Still, humans are alot different from mice...

[Tank101]

THE BRAIN! YOU MUST DESTROY THE BRAIN!

[JurseyRider734]

I can just see it. The person they test it on is going to become some superhero.

That would be so cool.

[talisman]

Think of the average US soldier given a shot of these cells. Unstoppable.

[QreepyBORIS]

Are you sure this isn't bullshit? :O

y halo thar, wolverine

[Kenzya]

Besides some kind of buzz phrase there's really nothing more to say than amazing.

[Tasuke]

Does it say in their how long it takes them to regenerate?
'Cuz I didn't see it, and that seems to be something of
some importance

[Sol_Solis]

That is crazy, k?

[ToshX]

Silly English and their cure for uncurable diseases.

[justaguy]

you could cut off your penis and grow a bigger one

isn't that awesome?

[gardyloo]

Originally Posted by Tasuke

Does it say in their how long it takes them to regenerate?
'Cuz I didn't see it, and that seems to be something of
some importance

yeah I got to know how long I'm going to be laying on the ground groaning after I jump out of a plane

[Tasuke]

Originally Posted by gardyloo

yeah I got to know how long I'm going to be laying on the ground groaning after I jump out of a plane

I think that if you jumped outta a plane that you would hit the
ground and be instantly crushed bones and organs and everything
It would be quite useless. But, imagine if you had to cut off your hands!
You could try playing with the stubs and slowly grow your whole hand back!

[ddrruler]

Yea it says you could regenerate but what about the pain...

[Jam930]

I'm sure that cutting off your leg or something would still kill you.

Simply because you'll lose a lot of blood.

x.x


The side affects of this are probably fatal. Only simple organisms can do it for a reason... mice aren't that complicated... and there's probably something very wrong with them that you can't pick up from experiments.

...and I'm not just talking about something like drowsiness or a bad mood.

[whorlichan]

Okay, what kind of moron, even one who can regenerate, is going to cut off his leg and not DO SOMETHING about blood loss? If you're able to regenerate something, and you've grown up with this ability, surely you will have learned about the best way to keep yourself from dying until the limb grows back.

What I wonder about is the heart regeneration--what keeps them going while that's going on? Or is this just small cells that otherwise wouldn't grow back, and not really as earth-shattering as the article makes it seem...

I do have to agree with Jamie (gasp!) that there's a lot they're not saying in this article. Further experimentation will probably show that their regenerated cells break down easier or earlier, or that they're made of Cheez Whiz instead of real cellular material, or something that will keep this from being as great as it could be.

Originally Posted by Jam930

mice aren't that complicated...

Okay, you try making one.

Seriously, the minute complexities of even "simple" life-forms is beyond comprehension. This is why we can't just invent new species, but rather have to modify existing ones.

[Tsuguri]

So, now we have undying mice. Lovely. Build a better mouse trap they say...

[ImEric12]

That's pretty awesome.

And yeah, seems like it would hurt like a bitch.