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Scientists Demonstrate Mammalian Tissue Regeneration
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."
Just being alive causes cancer, eventually ...
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?
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?
On the one hand you take life too seriously, and on the other, you do not take playful existence seriously enough. Seth
Hell yes! We can also get sustainably harvested bacon!
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...
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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?
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"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.
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But this still makes me giddy for the future of Medicine.
Nothing lasts forever but the certainty of change.
And it is easy to run away without a limb at all?
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.
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.
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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.