Scientists Demonstrate Mammalian Tissue Regeneration 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."
Re:So (Score:2, Insightful)
Just being alive causes cancer, eventually ...
It will be interesting to see... (Score:5, Insightful)
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?
Which way first? (Score:4, Insightful)
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?
Re:Now I can finally start my restaurant... (Score:1, Insightful)
Hell yes! We can also get sustainably harvested bacon!
Re:I for one... (Score:5, Insightful)
Re:It will be interesting to see... (Score:5, Insightful)
Remember, you are not a newt.
Be careful when fooling Mother Nature (Score:2, Insightful)
Re:It will be interesting to see... (Score:5, Insightful)
Re:I for one... (Score:5, Insightful)
"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:So (Score:3, Insightful)
And the Rugged good looks - in your case, anyways.
It takes a special kind of man to pull off that haircut.
Re:Be careful when fooling Mother Nature (Score:4, Insightful)
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:It will be interesting to see... (Score:3, Insightful)
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:Be careful when fooling Mother Nature (Score:2, Insightful)
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.
I don't know anything beyond high school biology. (Score:3, Insightful)
Re:I for one... (Score:3, Insightful)
If simply switching off the one gene is enough to allow regeneration, then it WOULD happen with an incidence similar to other single base pair change genetic defects. Something else is going on here. It could be that larger animals with the gene turned off die in the womb or something.
Re:Newt Doctors? (Score:3, Insightful)
What medical care do newts have access to?
It's incredibly funny to watch all the well-fed deep thinkers here scratch their heads and try to come up with complicated solutions to a trivial problem: cold blooded animals don't have to keep eating on a daily basis to survive. Ergo, they have time to regenerate. They can just find a place to curl up while it happens.
Warm blooded animals need a much more regular food supply. Ergo, there is an advantage to them in a fast and adequate healing.
No mysterious cancer-causing whatevers need be invoked. It is most probably a simple issue of energy budget.
Re:I for one... (Score:3, Insightful)
Or perhaps most common injury is just a small scratch, not losing your limb. Even the result looks nasty, faster healing offers one very important benefit. Open wounds tend to infect and that can cause serious illness or even death without modern medicine. It is not hard to imagine that healing your wounds a day or two faster would decrease the chance of getting sick a big time.