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Scientists Demonstrate Mammalian Tissue Regeneration

Soulskill posted more than 4 years ago | from the wolverine-explained dept.

Biotech 260

telomerewhythere writes "A quest that began over a decade ago with a chance observation has reached a milestone: the identification of a gene that may regulate regeneration in mammals. The absence of this single gene, called p21, confers a healing potential in mice long thought to have been lost through evolution and reserved for creatures like flatworms, sponges, and some species of salamander. 'Unlike typical mammals, which heal wounds by forming a scar, these mice begin by forming a blastema, a structure associated with rapid cell growth and de-differentiation as seen in amphibians. According to the Wistar researchers, the loss of p21 causes the cells of these mice to behave more like embryonic stem cells than adult mammalian cells, and their findings provide solid evidence to link tissue regeneration to the control of cell division. "Much like a newt that has lost a limb, these mice will replace missing or damaged tissue with healthy tissue that lacks any sign of scarring," said the project's lead scientist.' Here is the academic paper for those with PNAS access."

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260 comments

So (4, Funny)

jimbobborg (128330) | more than 4 years ago | (#31508764)

We can all be Wolverine now? Cool!

Re:So (5, Funny)

Monkeedude1212 (1560403) | more than 4 years ago | (#31508794)

Minus the Claws. And the Adamantite interior. And the Rugged good looks - in your case, anyways.

Re:So (2, Insightful)

Chris Burke (6130) | more than 4 years ago | (#31509282)

And the Rugged good looks - in your case, anyways.

It takes a special kind of man to pull off that haircut.

Re:So (0, Interesting)

Anonymous Coward | more than 4 years ago | (#31508818)

I have a feeling this causes cancer, eventually...

Re:So (2, Insightful)

Anonymous Coward | more than 4 years ago | (#31508932)

Just being alive causes cancer, eventually ...

Re:So (5, Informative)

TheMeuge (645043) | more than 4 years ago | (#31509134)

I have a feeling you should know something about the subject before weighing in.

p21 knockout mice don't appear to get cancer more than wild-type mice, interestingly enough...

It's interesting, because p53 is a major regulator of p21 expression, and p21 itself is a major player in regulating cell cycle progression into S-phase, thus controlling cell replication. p53 knockouts, on the other hand, are extremely prone to cancer, as p53 is one of the most important tumor-suppressor genes.

The paper is interesting because the authors demonstrate that two separate strains of mice that contain a p21 deficiency can both regenerate differentiated tissue (measured by looking at ear-hole closure), supporting the link between p21/cell cycle progression and tissue regeneration. Whether this is of consequence therapeutically is a different story, but I'd be very interested to see the same study repeated in wild-type mice being fed or injected a small molecule p21 inhibitor.

caveat (4, Informative)

TheMeuge (645043) | more than 4 years ago | (#31509230)

Of course the caveat to using mice to judge how a gene affects long-term development of cancer is that there really is no "long-term" on a human scale in mouse studies, since they only live about 3 years at most.

I'm also not entirely familiar with the effect of p21-deficiency in cases where major tumor suppressors are deregulated or otherwise deficient. It is feasible that in the absence of further regulation, the absence of a major cell cycle checkpoint will lead to a more severe phenotype, whether in terms of being more tumor prone, or development of more aggressive tumors.

Re:caveat (1)

poetmatt (793785) | more than 4 years ago | (#31509468)

what was the reason we commonly use mice again? I don't remember the exacts, but isn't it something like their immune systems respond similarly or something?

Re:caveat (3, Informative)

egomaniac (105476) | more than 4 years ago | (#31509638)

Primarily because they are cheap to breed and raise, take up very little space, reach maturity quickly, and people usually don't freak out about experiments on mice the same way they would on (say) primates.

They are also an acceptable human analogue in that they generally respond to medication and treatments similarly to how a human would; there are certainly other animals which are better models, but there are logistical, economic and public relations issues with trying to keep hundreds of chimpanzees in order to punch holes in their ears.

Re:caveat (2, Interesting)

somersault (912633) | more than 4 years ago | (#31509800)

The article also says this:

In fact, the researchers saw an increase in apoptosis in MRL mice -- also known as programmed cell death -- the cell's self-destruct mechanism that is often switched on when DNA has been damaged. According to Heber-Katz, this is exactly the sort of behavior seen in naturally regenerative creatures.

Does that mean shorter lifespan for the lifeform overall, or does it simply mean that individual cells will die regularly and then quickly be regenerated?

Re:So (1)

Drakkenmensch (1255800) | more than 4 years ago | (#31509388)

As long as p53 remains correctly active and functional, p21 inhibition has a potential to become a major cure treatment for a variety of ailments, from third degree burns to diabetes... up to any number of currently untreatable problems. Such a promising cure could possibly be upgraded, research pending, to a magic bullet vaccine status.

Re:So (1)

beelsebob (529313) | more than 4 years ago | (#31509574)

While in general I agree with your statement about not wading into something I don't know about, I'm going to do it anyway :P

p21 was evolved out of mammals, if it's got this wondrous healing ability attached to it, it makes very little sense for it to have not had a *major* impact on the fitness of creatures without it unless it also gives some major benefit by having it present. I'm not going to claim it protects against cancer, instead merely make a vague statement along the lines of "we'd better watch out carefully when removing something evolution has decided should appear in fit creatures".

Re:So (3, Interesting)

Scubaraf (1146565) | more than 4 years ago | (#31509654)

The cancer concern is a legitimate one. These p21 knockouts are lab mice kept in clean conditions. They may not develop cancers in a three year span, but that demonstrates little about the oncogenic potential in humans.

I'm assuming there is some evolutionary reason for curtailing a vigorous healing response. It maybe to reduce the cancer rate, but it could just as simply be something else very important - regulation of immune response for example.

One potentially useful experiment would be to challenge these mice with carcinogen (like ENU) and see what their cancer rate is compared to controls. Alternatively, you could use genetic means (insertion of oncogenes or mating to mice with knocked out tumor suppressor genes) to see if the cancers they develop are more aggressive or more likely to metastasize. In any case, this is a very cool finding.

Re:So (0)

Anonymous Coward | more than 4 years ago | (#31509162)

I just want to know if the bird on a mans penis has been regenerated yet?

Re:So (1)

icannotthinkofaname (1480543) | more than 4 years ago | (#31509840)

Actually, my first thought was that if I can regenerate, then all I'm missing is a TARDIS.

brb, off to find some TARDIS coral so I can grow my own TARDIS.

Re:So (1)

interkin3tic (1469267) | more than 4 years ago | (#31509856)

We can all be Wolverine now? Cool!

More like Deadpool. [wikipedia.org]

However, his healing factor results in massive scar tissue causing his appearance to be severely disfigured. An unanticipated side effect of the therapy was a rapid acceleration of cancerous tumors as well, causing them to quickly spread across his entire body as soon as his powers fully activated.

Except without the funny one liners, awesome assasin skills, teleporter, or probably the rivalry with wolverine. I suppose you could wear the costume though and get in a fight with a real wolverine.

Now I can finally start my restaurant... (5, Funny)

Culture20 (968837) | more than 4 years ago | (#31508792)

Now I can finally start my restaurant (which specializes in mouse-tail delicacies) without PETA breathing down my neck. "Look: it's growing back!" Mouse-tail soup anyone?

Re:Now I can finally start my restaurant... (1, Insightful)

Anonymous Coward | more than 4 years ago | (#31508996)

Hell yes! We can also get sustainably harvested bacon!

Re:Now I can finally start my restaurant... (2, Interesting)

Hatta (162192) | more than 4 years ago | (#31509374)

Of course PETA believes any sort of servitude by animals is the same as slavery. They'll never be happy. After all, if they ever got everything they wanted they'd have to find something useful to do with their lives.

Re:Now I can finally start my restaurant... (0)

Anonymous Coward | more than 4 years ago | (#31509532)

And they are willing to get naked to prove their point.

Or as my S.O. puts it 'im not being whory I am making a political statement.'

I for one... (1)

trurl7 (663880) | more than 4 years ago | (#31508844)

...welcome our new, non-scarring, regenerating....

too easy, forget it.

Re:I for one... (4, Insightful)

ircmaxell (1117387) | more than 4 years ago | (#31508998)

Well, they claim that they thought it was "lost to evolution"... I assume the fact that the gene is not active today is the result of evolution. So that implies the question Why is it inactive? I would think the ability to regenerate body parts on demand would be an evolutionary advantage, wouldn't it? So something must not work correctly (or there must be some kind of side effect)... It could be as simple as we didn't have enough nutrition at the time to be able to support it, and would die of malnourishment when we'd otherwise live with the injury... But I do agree, it does seem "too easy". They must be a negative here that we haven't figured out... I guess it's time to welcome our new self-healing mouse overlords...

Re:I for one... (2, Interesting)

Captain Splendid (673276) | more than 4 years ago | (#31509156)

Macro vs Micro. Regenerating body parts is great. Pretty much freezing genetic diversity with a bunch of near immortal beings? Not so much.

Re:I for one... (1)

TroyM (956558) | more than 4 years ago | (#31509168)

The risk of cancer seems the most likely explanation. Anything that promotes new cell growth also brings the risk of cancer if the cell growth goes out of control. Maybe since mammals tend to live longer than amphibians, cancer is a bigger threat than losing a limb?

Re:I for one... (1)

geekoid (135745) | more than 4 years ago | (#31509330)

In this study there was no change in cancer rates.

Evolution is 'good enough'. Meaning it isn't perfect, and if you can still produce, then it's successful. It could just be off by chance. If I were to make a wikld guess, I would say that this way takes more energy then are current way of healing. So it 'fell' out of use and there hasn't been in random mutation that turned it on and provided a substantial advantage over out current environment.

I would also guess this gene has been turned off for a very long time. Possible from before Homo Sapiens.

Now, get this is drug form an gimme. I wan to regenerate internal organs to there optimal state. No more scarring of the heart. Man, this could be great.

Re:I for one... (2, Interesting)

nblender (741424) | more than 4 years ago | (#31509220)

Not all mutations are good. Some mutations are bad. Sometimes multiple mutations occur at the same time... Maybe another highly beneficial mutation occurred at the same time as this one was lost... Imagine losing a limb... Not as easy to run away from predators while your limb is growing back... May not have been advantageous enough..

Not all mutations are bad? (2, Interesting)

Anonymous Coward | more than 4 years ago | (#31509620)

This might be true, the bad mutation might even be non fatal but that is not really the point. The thing to consider is the evolutionary advantage (or disadvantage) it gives. I would think that bad mutations give an evolutionary disadvantage and thus be selected against. So the question really is... "What sort of evolutionary advantage does it impart?" I really don't know the answer and I suspect that the researchers are just beginning to answer that question.

Re:I for one... (1)

kalahann (101218) | more than 4 years ago | (#31509240)

... But I do agree, it does seem "too easy". They must be a negative here that we haven't figured out... I guess it's time to welcome our new self-healing mouse overlords...

yup, that's because when they die they become zombies and start eating their siblings !

Re:I for one... (4, Insightful)

Dr. Evil (3501) | more than 4 years ago | (#31509246)

"I would think the ability to regenerate body parts on demand would be an evolutionary advantage"

What advantage could regeneration provide when survival rates for amputation were abysmal before modern medicine?

Maybe changes in bacteria made regeneration pointless in larger lifeforms (which take longer to heal)?

It's speculation, but I guess the only way we can know if it can be done is to experiment.

Re:I for one... (0)

Anonymous Coward | more than 4 years ago | (#31509348)

It could be an energy issue. Organisms running around regenerating all of the time would use a lot of biological energy. That means a lot of food intake. If you live on subsistence levels of food, your might not have the energy to keep regenerating. So may be your body slowly over times loses the ability to regenerate because you basically don't do it anyway.

Re:I for one... (4, Interesting)

david.given (6740) | more than 4 years ago | (#31509380)

I would think the ability to regenerate body parts on demand would be an evolutionary advantage, wouldn't it?

Not necessarily. A lot of small animals are pretty much disposable: they're sufficiently fragile that there's only a very narrow boundary between a trivial injury and a fatal one. (And anyone who's kept small birds and animals will know that if they're hurt beyond a certain point they'll simply go into shock and die.)

So it's entirely plausible that the gene might have been caused by a spot mutation very early on while all mammals were basically mice, and it then had a sufficiently small effect on actual survivability that the trait didn't get bred out. Later, once the small, disposable animals turned into large, expensive ones, it was too late.

It is interesting that both birds and animals appear to lack this trait, though. We both descend from much the same sort of lizards but in different directions. Finding out exactly where this gene sequence appeared might be productive.

(Of course, I want to know when we'll be able to get gene therapy to suppress the gene. Assuming it works in humans, and that the gene doesn't do anything else critical, it might even be fairly straightforward! But probably won't happen soon and I'm certainly not volunteering to be the guinea pig...)

Re:I for one... (1)

Spatial (1235392) | more than 4 years ago | (#31509382)

Evolution doesn't converge toward perfection, or even improvement.

Why is it inactive? Its inactivity didn't kill our ancestor, and they done fucked a bitch. Here we are.

Re:I for one... (0)

Anonymous Coward | more than 4 years ago | (#31509426)

p21 (CIP1) is a tumor suppressor protein that stops cells from dividing after DNA damage. So, yeah...

A more meta point - there are two healing mouse strains discussed, the p21 mutant and the MRL mouse. Since sequencing one gene is relatively cheap and easy (as opposed to whole genome fishing expeditions), it's safe to assume the MRL mouse doesn't have a p21 mutation, so there may still be hope on that score.

Re:I for one... (2, Interesting)

PaulMeigh (1277544) | more than 4 years ago | (#31509432)

When you are driving in your car and run over a nail, it's often cheaper to just patch the tire rather than to replace it. You're generally back on the road faster as well.

Re:I for one... (1)

The End Of Days (1243248) | more than 4 years ago | (#31509442)

There only has to be a negative if you assume evolution is guided. If things just continue to work from the survival point of view, it doesn't matter one whit to evolution if there was an advantage lost.

Re:I for one... (2, Interesting)

Anonymous Coward | more than 4 years ago | (#31509454)

In case of large animals it may take very long to replace the lost body part. Maybe adaptation is simply faster, and more energy efficient. Same probably for grievous wounds. Or maybe it's just not worth it at all, and the time it took to replace or get over such injury resulted in death of both. But the suppressed gene code was easier to write? Damn lazy programmers...

Re:I for one... (0)

Anonymous Coward | more than 4 years ago | (#31509506)

In a fight, you know whats better than walking away the winner with a bloody stump? Walking away without a scratch.

Evolution could just as easily leaned towards those who were faster, smarter, or would simply breed fast enough that they would avoid getting any major injuries that would require regeneration before passing on their genes.

So this is what hell will be... (0, Troll)

mtrachtenberg (67780) | more than 4 years ago | (#31508846)

So this is what the religions were talking about when they talked about hell. Everyone lives forever, one hundred people have all the money, and Sarah Palin is President-for-Life.

Degeneration (2, Funny)

tedgyz (515156) | more than 4 years ago | (#31508876)

You know this discussion will degenerate into how this can be applied to growing a longer penis.

Re:Degeneration (3, Funny)

protodevilin (1304731) | more than 4 years ago | (#31508936)

Then I hope it doesn't involve having to amputate the penis first.

Re:Degeneration (1)

hanabal (717731) | more than 4 years ago | (#31509216)

if it did thought, would you. I mean if you could grow any penis size you wanted but you had to cut your original one off to get it, would you. Bonus points if you weren't allowed anaesthesia as that affects the regrowth.

Re:Degeneration (1)

JavaBear (9872) | more than 4 years ago | (#31509152)

You know this discussion will degenerate into how this can be applied to growing a longer penis.

No, but spammers are sure to find a way to try and sell that point

Re:Degeneration (1)

Chris Burke (6130) | more than 4 years ago | (#31509378)

*Jamaican^W WoW troll voice*

They say that when you cut off an extremity it regenerates a little bigger.

Don't believe it.

very probably this will cause cancer (0)

Anonymous Coward | more than 4 years ago | (#31508954)

Because cancer happens when cells start to divide much faster

It will be interesting to see... (5, Insightful)

fuzzyfuzzyfungus (1223518) | more than 4 years ago | (#31508960)

What the side effects are. One would(perhaps naively) assume that regeneration is an obvious survival advantage, and that losing regenerative capabilities would be a handicap. That being so, one would tend to suspect that an anti-regeneration gene would be fairly strongly selected against. Since this gene is, in fact, rampant in mammals, one is led to the suspicion that there must be some sort of upside.

Is it something more or less irrelevant to modern humans(at least those wealthy enough to ever be genetically engineered), something like "without any sort of medical care, most serious injuries were fatal before regeneration could occur, so the extra energy costs weren't worth it", or is it some kicker of the "Well, without a whole bunch of other adaptations possessed by certain amphibians and creepy-crawlies, you'll 'regenerate' yourself entirely full of tumors by age 20." flavor?

Re:It will be interesting to see... (5, Insightful)

ColdWetDog (752185) | more than 4 years ago | (#31509026)

Think of it this way: MOST of the time, your body tries mightily to STOP things from growing - those are typically cancers (uncontrolled cell division). It may have been easier in the evolutionary sense to shut down regeneration than to deal with it's consequences.

Remember, you are not a newt.

Re:It will be interesting to see... (0)

Anonymous Coward | more than 4 years ago | (#31509208)

Remember, you are not a newt.

Well, I was. But I got better...

Re:It will be interesting to see... (2, Interesting)

pesho (843750) | more than 4 years ago | (#31509284)

I second this. p21 is what you call a 'tumor suppressor' gene. Without p21 it is significantly easier to get cancer. It would matter less to mice, because of their short lifespan and different DNA damage repair strategy (fix aggressively active genes, don't care much about the rest). For humans with life span ten times longer compared to mice, this is real deal breaker. These mice also appear to have some sort of autoimmune disease.

Re:It will be interesting to see... (1)

Cormacus (976625) | more than 4 years ago | (#31509450)

Think of it this way: MOST of the time, your body tries mightily to STOP things from growing - those are typically cancers (uncontrolled cell division). It may have been easier in the evolutionary sense to shut down regeneration than to deal with it's consequences.

Agreed, but this line from the article is very iteresting:

Heber-Katz said. "In these mice without p21, we do see the expected increase in DNA damage, but surprisingly no increase in cancer has been reported." In fact, the researchers saw an increase in apoptosis in MRL mice -- also known as programmed cell death -- the cell's self-destruct mechanism that is often switched on when DNA has been damaged

So I guess the question is whether programmed cell death has certain other consequences.

Re:It will be interesting to see... (4, Insightful)

bcmm (768152) | more than 4 years ago | (#31509070)

Scarring is much faster, and probably carries a lower risk of infection for creatures that don't have access to medical care.

Re:It will be interesting to see... (1)

Spatial (1235392) | more than 4 years ago | (#31509336)

One would(perhaps naively) assume that regeneration is an obvious survival advantage, and that losing regenerative capabilities would be a handicap. That being so, one would tend to suspect that an anti-regeneration gene would be fairly strongly selected against. Since this gene is, in fact, rampant in mammals, one is led to the suspicion that there must be some sort of upside.

We can't synthesise vitamin C either, but there's no benefit to that. Almost all other animals can synthesise it, but we get scurvy and die unless we ingest it.

If it doesn't kill you before you can reproduce, and it doesn't make you infertile, it can be passed on. We lack that ability because one of our ancestors lacked it, but survived and reproduced regardless.

Because of that low standard for selection, it's relatively easy for a trait to be irrelevant to the selection process, good or bad.

Re:It will be interesting to see... (1)

Tom Boz (1570397) | more than 4 years ago | (#31509400)

I think it's more the extra energy costs that led to using scarring rather than regeneration. It's my understanding (having taken 1 biomaterials class) that scarring is also a relatively useful response in most situations; that is, it usually is a sub-par solution to the problem, but since it works the same everywhere on the body, that's an advantage. It can also happen far more quickly than regeneration, I would assume. Either way, this will be an interesting development to follow - who knows what side effects we'll find?!

Re:It will be interesting to see... (2, Insightful)

Scrameustache (459504) | more than 4 years ago | (#31509410)

What the side effects are. One would(perhaps naively) assume that regeneration is an obvious survival advantage, and that losing regenerative capabilities would be a handicap. That being so, one would tend to suspect that an anti-regeneration gene would be fairly strongly selected against. Since this gene is, in fact, rampant in mammals, one is led to the suspicion that there must be some sort of upside.
Is it something more or less irrelevant to modern humans(at least those wealthy enough to ever be genetically engineered), something like "without any sort of medical care, most serious injuries were fatal before regeneration could occur, so the extra energy costs weren't worth it", or is it some kicker of the "Well, without a whole bunch of other adaptations possessed by certain amphibians and creepy-crawlies, you'll 'regenerate' yourself entirely full of tumors by age 20." flavor?

Well, FTFA: "In normal cells, p21 acts like a brake to block cell cycle progression in the event of DNA damage, preventing the cells from dividing and potentially becoming cancerous," Heber-Katz said. "In these mice without p21, we do see the expected increase in DNA damage, but surprisingly no increase in cancer has been reported."
In fact, the researchers saw an increase in apoptosis in MRL mice -- also known as programmed cell death -- the cell's self-destruct mechanism that is often switched on when DNA has been damaged. According to Heber-Katz, this is exactly the sort of behavior seen in naturally regenerative creatures.

Maybe this gene was like the scaffolding you build before building an arch, and now that we have evolved the rest of the cancer-fighting-arch, we can remove the p21 scaffolding.
Or maybe this will end up like thalidomide. I say we proceed with cautious optimism.

Re:It will be interesting to see... (1)

structural_biologist (1122693) | more than 4 years ago | (#31509554)

In the PNAS paper published by the scientists, they noted that the "healer" strains of mice deficient in the p21 protein showed increased signs of DNA damage. These observations make sense because p21 is a key component of biochemical stress response pathways that, for example, stop a cell from dividing after its DNA has been damaged.

In fact, p21 is one of the proteins that carries out instructions from the infamous p53 protein (the tumor-suppressor protein commonly referred to as the "Guardian of the Genome" that is mutated in over 50% of cancers). So, in terms of applications, disrupting p21 function in order to induce regenerative abilities would be like playing with fire: such a modification would shut down one pathway through which p53 protects cells against cancer. If one were to think of using this knowledge for regenerative medicine, applications where p21 is temporarily disabled (for example, through transient application of RNA interference) would be better than permanently shutting off the gene.

Overall, however, this paper produces some nice evidence pointing to DNA damage as an important mechanism in aging. This is of course known, but it's always nice to see these concepts pop up in fields related to aging.

Re:It will be interesting to see... (1)

AceJohnny (253840) | more than 4 years ago | (#31509624)

you'll 'regenerate' yourself entirely full of tumors by age 20.

The article states: "In these mice without p21, we do see the expected increase in DNA damage, but surprisingly no increase in cancer has been reported."

Also, I suggest other /.ers read the article. It is high quality, not a random blog post.

Which way first? (3, Insightful)

spaceman375 (780812) | more than 4 years ago | (#31508962)

The next step is to make some p21 specific RNA interference molecules and shut it down in an adult, non-regenerative mouse. Then clip its ear and see what happens.
Since it also increases apoptosis, would this make a good diet pill?

Spider-Man's Lizard (1)

Akido37 (1473009) | more than 4 years ago | (#31508984)

Isn't this the backstory to the Lizard? He tries to regrow his arm using amphibian DNA, and whoops - he turns into a Lizard.

Hm, it sounds really stupid now that I've typed it out.

Re:Spider-Man's Lizard (0)

Anonymous Coward | more than 4 years ago | (#31509310)

Mary Jane loves Spider-Man's Lizard!

Re:Spider-Man's Lizard (2, Informative)

serialband (447336) | more than 4 years ago | (#31509326)

Isn't this the backstory to the Lizard? He tries to regrow his arm using amphibian DNA, and whoops - he turns into a Lizard.

Hm, it sounds really stupid now that I've typed it out.

Lizards are reptiles.

Be careful when fooling Mother Nature (1, Insightful)

XB-70 (812342) | more than 4 years ago | (#31509060)

This is, obviously, the holy grail for many injuries and holds out immense hope for amputees etc. etc. There's one thing about it that has me concerned. Darwinism is cruel. It causes the weak to fall by the wayside of evolution and the strong to perpetuate the best of the species. Nature does things for a reason. The question in the back of my mind is: if we fool with this, what are the underlying natural reasons for the gene to be turned off? We aught to be taking a very close look at the consequences of turning on this gene before we start trying to fool mother nature. In short, I'm not against it, I'm just concerned and cautious - are you?

Re:Be careful when fooling Mother Nature (1)

MartinSchou (1360093) | more than 4 years ago | (#31509232)

Which is why we do tests on lab animals instead of injecting random people with completely untested gene therapies.

But don't tell PETA. They don't want you to do lab tests on animals, but they also don't want to volunteer themselves as human guinea pigs.

Re:Be careful when fooling Mother Nature (3, Insightful)

compro01 (777531) | more than 4 years ago | (#31509286)

I can think of a couple reasons why this feature may have been dropped. nutrition (regrowing something is a hell of a lot more resource intensive than just closing the hole) and infection prevention (just closing the hole is a lot faster than regrowing something, so less chance of it getting infected). Both of these were relevant considerations very recently and evolution is pretty slow.

Re:Be careful when fooling Mother Nature (2, Interesting)

DrMaurer (64120) | more than 4 years ago | (#31509648)

I think you have an interesting point here on the resource requirements of regeneration. Part of the obesity problem is that our bodies evolved to store whatever they couldn't use right now for later, so it stands to reason that such things were "turned off" for efficiency's sake. We didn't necessarily evolve in a land of plenty

As for infection rates, I would like to see that study done, too...

Re:Be careful when fooling Mother Nature (1)

Securityemo (1407943) | more than 4 years ago | (#31509448)

We're all concerned and cautious, but where would we be in science and technology without enthusiasm and dreaming? Nobody's just going to start toggling DNA markers and associated cell machinery in humans without lots of testing on lower lifeforms - unless, of course, the human subject has nothing to lose.

Re:Be careful when fooling Mother Nature (1)

Scrameustache (459504) | more than 4 years ago | (#31509452)

the underlying natural reasons for the gene to be turned off? We aught to be taking a very close look at the consequences of turning on this gene

Other way around: The absence of this single gene, called p21, confers a healing potential in mice

Re:Be careful when fooling Mother Nature (2, Insightful)

Anonymous Coward | more than 4 years ago | (#31509458)

Sure anyone with even a vague knowledge of evolution and basic highschool genetics will worry, but as long as they make vague promises like bigger dicks, hair regrowth and weight loss pills, they won't have any problems.

Re:Be careful when fooling Mother Nature (1)

The End Of Days (1243248) | more than 4 years ago | (#31509522)

Darwinism is cruel.

Darwinism is a description of natural processes. Cruelty requires intent, and there is no evidence of intent in the underlying processes, never mind the description of those same.

Nature does things for a reason.

Again, there is no evidence of this point of view.

I'm not sure how you got modded up. I can only assume the intelligent design folks somehow got points today.

Re:Be careful when fooling Mother Nature (2, Interesting)

zwei2stein (782480) | more than 4 years ago | (#31509536)

Any form of health care is dangerous this way.

Consider this: we can (and do) save many children with birth defects, often we are succesfull enough so that they can leard normal life (and even be oblivious to any issues). Problem is that some of theese defects are hereditary. Guess what? Next generation is worse off as far as ratio of defects is concerned.

We obviously will never do "sparta" thing and kill of children society finds undesirable. Nor will anyone with genetic defect be prevented from having children. Neither is civilized resolution or would be even remotelly popular (would you want to risk your child falling victim to it? noone would.)

Anyway, I would not worry about this particular medical advance. This regeneration propably caused cancer if it got out of controll (cancer with nondiversified cells as medium is quite scarry).

Re:Be careful when fooling Mother Nature (4, Funny)

lawpoop (604919) | more than 4 years ago | (#31509710)

Darwinism is cruel... Nature does things for a reason.

Narture wants to be anthropomorphized ;)

It nature is so cruel and barbaric, then for what reason did it evolve human beings who feel sympathy, empathy, are able to learn, and practice healing arts?

Highlander? (0)

Anonymous Coward | more than 4 years ago | (#31509090)

Then the immortals are just humans with p21 expressed?

Why was that gene there? (1)

gmuslera (3436) | more than 4 years ago | (#31509178)

Somewhat not being able to regenerate (or something deeply related with that) gave us an evolutionary advantage. Is pretty tempting to just make pills to turn that off, but what will be the cost? Don't think that you will fall into not being able to get older or make new memories, but still stinks to too good to be true.

All very nice stuff, but... (2, Interesting)

Nihiltres (1161891) | more than 4 years ago | (#31509180)

...in practice, do we have the technology to knock this gene out in humans? That's the key thing. Either you have to engineer every human to have the gene before birth, or you have to do a live fix. And a live fix has all sorts of complications.

Of course, I'm completely ignoring potential side effects. This is best if you imagine a drug for it being advertised: "Regrowitol may cause side effects including cancer, accessory limbs, mutation into evil lizard creature..."

We're living in the future, sure. But we don't have all the cheat codes for reality yet.

Oh yes! (0)

Anonymous Coward | more than 4 years ago | (#31509190)

What the fuck? Lady Gaga is kind of hot. I know she has a penis, but if I could have sex with her and Beyonce...well butter my ass and call me a homo.

What's the downside? (4, Informative)

Biotech9 (704202) | more than 4 years ago | (#31509204)

A lot of people are asking why evolution has taken away our regenerative capacities, and are guessing what the downside of this regeneration is.

P21 is involved with anti-cancer. It arrests the cell cycle when DNA damage occurs, allowing the damage to be repaired (so mistakes are not carried forward into new generations). Or if the damage is too severe, the cell is made senescent (they lose the ability to reproduce and instead lead out a gentle retirement, performing their normal job until they just die of old age)

P21 knockout mice show a lot of carcinomas and P21 is also up-regulated by and works to remedy excessive oxidative stress. It's very unlikely this research is going to lead to a pill that knocks out P21 and lets us grow limbs back. It will only lead to a greater understanding of how our pathways work.

Re:What's the downside? (1)

Cormacus (976625) | more than 4 years ago | (#31509496)

So there was an interesting line in the article:

Heber-Katz said. "In these mice without p21, we do see the expected increase in DNA damage, but surprisingly no increase in cancer has been reported." In fact, the researchers saw an increase in apoptosis in MRL mice -- also known as programmed cell death -- the cell's self-destruct mechanism that is often switched on when DNA has been damaged

What are the consequences of apoptosis vs senescence?

Re:What's the downside? (1)

Chris Burke (6130) | more than 4 years ago | (#31509510)

Or if the damage is too severe, the cell is made senescent (they lose the ability to reproduce and instead lead out a gentle retirement, performing their normal job until they just die of old age)

I just heard one of my P21-arrested liver cells audibly scoff at that "gentle retirement" bit. :)

Re:What's the downside? (1, Interesting)

Anonymous Coward | more than 4 years ago | (#31509580)

Well, it's also useful for medical reasons. If we develop a molecule/protein that counteracts the protein fabricated by p21, we could temporarily get the healing power (for example, to heal damage to internal organs), without giving up the anti-cancer protection. This would be localized, and not too dangerous as the effects are temporary.

Safety switch. (1)

Ihlosi (895663) | more than 4 years ago | (#31509294)

My guess is that while not having this gene results in wonderous regenerative abilities, it'll also increase your chances of developing cancer before the age of 20 by a bajillionfold. Not a problem for mice, but certainly a problem for men.

Anyone think about what it's going to feel like? (0)

Anonymous Coward | more than 4 years ago | (#31509318)

Losing an appendage and regrowing it? That's gotta sting!

PNAS (0)

Anonymous Coward | more than 4 years ago | (#31509394)

Be careful how you pronounce this.

Why won't God heal amputees? (1)

Holammer (1217422) | more than 4 years ago | (#31509404)

... when science does? Cheap shots aside, here's hoping that this actually get a practical application that will help people in the future.

Wait, so.. (1)

flintmecha (1134937) | more than 4 years ago | (#31509476)

...the expierment involves removing the gene which prohibits the regeneration.
Interesting how that works. I would think the existence of a gene would grant the existence of a trait, not the absence of it. Then again, I'm no biologist. So mammals evolved this gene which prevents tissue regeneration. I wonder why?

Anyway, this is really cool.

evolution purists (0)

Anonymous Coward | more than 4 years ago | (#31509768)

For the evolution purists out there. Don't worry about it. Genetic problems are always self correcting, despite all our efforts to the contrary. Disaster and catastrophe are always around the corner. As a race, we will either be strong enough to survive or smart enough to compensate...or not. After all, if you are a purist, and we go the way of the dinosuar, that it is as it should be, right?

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