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Zebrafish Regenerative Ability May Lead To Help In Humans
esocid tips us to news out of Duke University Medical Center, where researchers have discovered a type of microRNA that is related to the ability of zebrafish to regenerate lost or damaged organs. This is the result of a study initiated after it was discovered that zebrafish were able to recover from "massive injury" to the heart through their own regenerative biology. The scientists hope to be able to use this information to bring about similar healing in humans. Zebrafish have also been helpful in cancer research.
"In zebrafish, one or more microRNAs appear to be important to keep regeneration on hold until the fish needs new tissue, the Duke researchers say. In response to an injury, the fish then damp down levels of these microRNAs to aid regrowth. Poss and many other cell biologists believe that mammals may have the same tissue regeneration capability as zebrafish, salamanders and newts, but that it is locked away somewhere in our genome, silenced in the course of evolution."
if i had a tail i'll play with it all day...
Human life expectancy is quite long by animal standards, so it seems like we probably just don't need this anymore. On the other hand, there are usually tradeoffs with these kinds of mechanisms, and turning it on again may have rather negative side-effects.
I'm reminded of a story from Analog in the 60s, where they figure out how to stimulate toot regeneration. Except that, once the technique has been in use for a while, they find out that it doesn't stop producing new teeth ...
Lacking <sarcasm> tags,
AGH! I have ears regenerating all over my body! Get them off!
Once you start despising the jerks, you become one.
In my fairly limited understanding of evolution theory, the features that help to survive are retained through the natural selection. Regeneration ability seems to help to survive - why would it be lost then? Could it be that the time required to naturally regenerate was so long that the animal weakened by the injury died anyway by natural (lack of food and/or water access, climatic factors) or violent (predators) death?
That would be my guess. There's a good bit of research where they tinkered with mouse genes to accelerate or slow telomere erosion, and found that the natural mouse is pretty close to the maximum lifespan possible. Faster erosion causes the mice die of old age sooner, but slower erosion results in more cancer deaths.
Regeneration may well have similar costs. Since all of the natural regenerators are poikilotherms, I would speculate that their overall lower metabolic rate has less risk of cancer. Giving up regeneration may well be the price we pay for warm blood.
Lacking <sarcasm> tags,
With Puppeteers it's slightly more "believable", because a Puppeteer's brain is under its back. The "heads" hold only the eyes and the mouth, as well as serving to manipulate objects like hands.
"Forever young" this is not.
... but as another poster pointed out, if this capability were activated on a temporary basis solely for the purpose of regenerating lost or damaged tissue, it would prove invaluable. Hell, if this did become practical, one could chop out diseased parts of an organ and simply regenerate them. Transplants could become a thing of the past. Lose an extremity? Regrow it!
Maybe not
The higher the technology, the sharper that two-edged sword.
The autodoc didn't grow his head back. It grew his body back, starting from only a head.
I recently contacted Ellen Heber-Katz, asking how the regenerating mice were progressing; they have not published anything about them in nearly two years. She replied that the mice are in fact still alive and breeding, which means that they have passed their life expectancy by at least half a year. She also said they will be releasing "lots of papers" in 2008.