It's a miracle: mice regrow hearts - [stunning news about tissue regeneration]

The Australian ^ | August 29, 2005

[snarks_when_bored]

It's a miracle: mice regrow hearts

29aug05

SCIENTISTS have created "miracle mice" that can regenerate amputated limbs or damaged vital organs, making them able to recover from injuries that would kill or permanently disable normal animals.

The experimental animals are unique among mammals in their ability to regrow their heart, toes, joints and tail.

And when cells from the test mouse are injected into ordinary mice, they too acquire the ability to regenerate, the US-based researchers say.

Their 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 titled Strategies for Engineered Negligible Senescence, at Cambridge University in Britain.

The research leader, Ellen Heber-Katz, professor of immunology at the Wistar Institute, a US biomedical research centre, said the ability of the mice at her laboratory to regenerate organs appeared to be controlled by about a dozen genes.

Professor Heber-Katz says she is still researching the genes' exact functions, but it seems almost certain 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 fetal 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."

Professor Heber-Katz made her discovery when she noticed the identification holes that scientists punch in the ears of experimental mice healed without any signs of scarring in the animals at her laboratory.

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

In another test some of the tail was cut off, and this also regenerated. Then the researchers used a cryoprobe to freeze parts of the animals' hearts, and watched them grow back again. A similar phenomenon was observed when the optic nerve was severed and the liver partially destroyed.

The researchers believe the same genes could confer greater longevity and are measuring their animals' survival rate. However, the mice are only 18 months old, and the normal lifespan is two years so it is too early to reach firm 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.

The Sunday Times

[HitmanLV]

WOW!!!!!!

[RightWingAtheist]

Hell of a supporting cast in that one.

[Ichneumon]

The kind of evolution you're talking about is called "intelligent design".

No, it isn't. No one "designed" dachshunds, they were made by helping along evolution. People *still* couldnt' design a dachshund from scratch.

[aposiopetic]

Professor Heber-Katz made her discovery when she noticed the identification holes that scientists punch in the ears of experimental mice healed without any signs of scarring in the animals at her laboratory.

Attention to detail pays off. Here is someone who sought an explanation for an interesting phenomenon instead of just going ahead with pre-planned experiments.

This is (at least some of) what science is supposed to be.

[Ichneumon]

Man cannot MAKE DNA, yet. When he attempts to do that feat , then he is playing God.

Yeah, yeah. We heard the same warnings when people "played God" by redirecting God's lightning with lightning rods, and by preventing God's wish that we endure pain by inventing anesthetics...

The list is endless.

You guys are welcome to go back to your caves if technology scares you.

[Ichneumon]

In one case the mice had their toes amputated -- but the digits grew back, complete with joints.

I can believe a lot of the other claims, but *this* one just doesn't seem very plausible. The formation of joints in the fetus is complex process involving a lot of "scaffolding" and subsequent programmed cell death, both of which don't seeme feasible in non-fetal conditions, especially when attached to amutated adult tissues. In short, the kind of "cellular coordination" that's possible (and necessary) during fetal growth doesn't seem possible on the "stump" of an adult limb. At least not to the point of producing a working, healthy joint as opposed to a rudimentary shadow of one.

I can't say I would mind being proved wrong, though, it would be wonderful if it were actually possible.

[PatrickHenry]

Don't forget pasteurization, immunization and (still a bone of contention among some Christian and Jewish sects) blood transfusions.

And fluoridation of the water supply. We must preserve the purity of our bodily fluids!

[Ichneumon]

And just exactly what the bleep does this have to do with evolution????? You have evolution on the brain.

What it has to do with evolution is that these mutant mice obviously evolved from the existing strain of experimental mice -- unless you want to claim that they were dropped into the lab by aliens while no one was looking. Now was that so hard to figure out?

[Alas Babylon!]

Well, perhaps but amphibians seem to be able to do this (regenerate limbs) outside of their fetal stages. The question I've always wondered is what exactly do frogs have that mammals do not? Perhaps these scientists are on to that?

[GovernmentShrinker]

No, but biologists could now engineer new single-celled organisms which could survive on Mars and evolve into more complex life forms. And we're getting VERY close to being able to engineer our own offspring to be able to survive in environments where humans can't presently survive. Intelligent design doesn't have to be instead of evolution, it can work alongside it.

[AdmSmith]

Here are some interesting articles (it might be something in this):

Cloning Stem Cells. 2004;6(4):352-63
The MRL mouse heart healing response shows donor dominance in allogeneic fetal liver chimeric mice.

Bedelbaeva K, Gourevitch D, Clark L, Chen P, Leferovich JM, Heber-Katz E.

The Wistar Institute, 3400 Spruce St., Philadelphia, PA 19104, USA.

We previously demonstrated that after a severe cryoinjury to the right ventricle of the heart, adult MRL mice display structural and functional recovery with myocardial tissue replacement resembling that seen in amphibians. The control non-regenerating adult C57BL/6 (B6) mouse shows a predominant scar response. In the present study, radiation chimeras reconstituted with fetal liver cells from either healer MRL or nonhealer B6 mice were generated to test for a transfer of phenotype. Allogeneic MRL fetal liver cells were injected into x-irradiated (9 Gy) B6 mice and B6 fetal liver cells were injected into x-irradiated MRL mice. In these allogeneic chimeras, the healing response to cardiac cryoinjury was predominantly of the donor phenotype. Thus, MRL fetal liver cells transferred the healing phenotype to the B6 nonhealer with the appearance of Y-chromosome positive, donor-derived cardiomyocytes in the injury site and MRL-like healing with little scar. Similarly, B6 fetal liver cells transferred the nonhealing phenotype to the MRL with little cardiomyocyte growth and an acellular B6-like scar. These results are in contrast to the ear hole closure response which was of the recipient phenotype. We conclude that, in the case of the heart, fetal liver-derived stem cells regulate regenerative healing.

and another one:

Philos Trans R Soc Lond B Biol Sci. 2004 May 29;359(1445):785-93.

The scarless heart and the MRL mouse.

Heber-Katz E, Leferovich J, Bedelbaeva K, Gourevitch D, Clark L.

The Wistar Institute, 3601 Spruce Street, Philadelphia, PA 19104, USA. heberkatz@wistar.upenn.edu

The ability to regenerate tissues and limbs in its most robust form is seen in many non-mammalian species. The serendipitous discovery that the MRL mouse has a profound capacity for regeneration in some ways rivalling the classic newt and axolotl species raises the possibility that humans, too, may have an innate regenerative ability. The adult MRL mouse regrows cartilage, skin, hair follicles and myocardium with near perfect fidelity and without scarring. This is seen in the ability to close through-and-through ear holes, which are generally used for lifelong identification of mice, and the anatomic and functional recovery of myocardium after a severe cryo-injury. We present histological, biochemical and genetic data indicating that the enhanced breakdown of scar-like tissue may be an underlying factor in the MRL regenerative response. Studies as to the source of the cells in the regenerating MRL tissue are discussed. Such studies appear to support multiple mechanisms for cell replacement.


and another

Cell Tissue Res. 2005 Jun;320(3):417-26. Epub 2005 Apr 23

Prior injury accelerates subsequent wound closure in a mouse model of regeneration.

Davis TA, Longcor JD, Hicok KC, Lennon GG.

Endogeny Bio Corporation, 9700 Great Seneca Highway, Rockville, MD 20850, USA. davist@nmrc.navy.mil

Tissue regeneration and scarless healing involves the complete replacement and functional restoration of damaged organs and tissues. In this study of the "scarless healing" MRL mouse model, we demonstrate that 2-mm diameter through-and-through holes made in the cartilaginous part of previously injured MRL mouse ears are closed more efficiently, and that the regenerative repair response is significantly accelerated compared with unprimed MRL and control "nonhealer" strains of mice. Accelerated healing was detected both locally and distally from the original site of injury indicating the involvement of systemic components such as circulating cell types or soluble factors. Histologically, we observed early differences during the wound repair process (before Day 4 post injury) with accelerated formation of blastema-like structures, epidermal downgrowths, and enhanced epithelium thickening in wound border zones in primed MRL mice versus unprimed MRL mice. Although the mechanism of tissue regeneration remains unclear, the results from this study justify the use of the MRL model for further experimentation directed toward the identification of proteins and cell types capable of stimulating scarless tissue regeneration.

[AdmSmith]

..and this Biochem Biophys Res Commun. 2005 Apr 29;330(1):117-22.

Isolation of wound healing/regeneration genes using restrictive fragment differential display-PCR in MRL/MPJ and C57BL/6 mice.

Masinde G, Li X, Baylink DJ, Nguyen B, Mohan S. Musculoskeletal Disease Center, JL Pettis VA Medical Center, Loma Linda, CA 92357, USA.

Wound healing in mammals can take several weeks to months and the process is always accompanied by scar formation. Wound healing mechanisms that mimic regeneration are not found in most mature mammalian tissues. However, the MRL/MPJ (MRL) mouse has the unique capacity to regenerate ear hole wound completely in less than a month. To identify genes involved in wound healing without a scar, we chose to use restriction fragment differential display-PCR to isolate genes differentially expressed in the MRL (good healer) mouse and the C57BL/6 (poor healer) mouse at different stages of wound healing. We identified 36 genes that were differentially expressed in the regenerating tissue of good and poor healer strains of which several genes are also genetically linked to wound healing and thus are potential candidate genes for scarless wound healing.

[RinaseaofDs]

This is a cure for MS. MS is when the myelin on the outside of the nerves and spinal cord develops gaps in it from deterioration, preventing the electrical signals from getting from the brain to the muscles.

This would fix that right now.

[Bernard Marx]

That's what they said about the invention of lightning rods, and anesthetics, too.

I'm no Luddite. But lightning rods and anesthetics are mere toys compared to the dangers posed by the misuse of bioengineering. I've lived on this earth long enough to know that if a thing can be done, someone will do it -- codes of ethics and laws be damned. Whether it's a sick Dr. Moreau-type or a misguided "environmentalist" determined to wipe out Gaia-threatening humans with a "designer virus," I think hubristic use of the technology will eventually get us. I hope I'm wrong but we're not even doing very well on the nuclear non-proliferation front these days, are we?

[Born Conservative]

[zot]

Thanks for the ping. A milestone in history, if it works as advertized. I would like to know what they did to develop this particular strain of laboratory mice.

[1lawlady]

Yeah, I saw the article. I thought it must be a hoax as it's almost too good to be true.

[PatrickHenry]

Placemarker and plug for The List-O-Links.

[MHGinTN]

"The Doctor gave me a pill and I grew a new kidney!" ... Elderly Lady on a gurney, Star Trek, The Journey Home.

[blurb]

What does this story have to do with evolution?