Thursday, July 2, 2009

An Arm And A Leg


Cell biologists studying salamanders at the Max Planck institute seem to have finally unravelled exactly how salamanders regrow lost limbs. It seems that a clump of cells called a blastema forms at the end of the stump. Previously, it was believed that cells attaching to the blastema become de-differentiated or "pluripotent"; that is, they are able to become any other type of tissue - bones, muscles or nerves for example.


The big news here is that researchers had previously hypothesized that the cells had to be reworked to an embryonic state to become become capable of regeneration. Studies of salamanders, however, shows the cells only regress a few generations when regenerating lost limbs. What this means is that, if the process can be duplicated in mammals - like us - a complete overhaul of the cells isn't required, just a fairly gentle regression.


There is a downside: regressing cells by a few iterations tends to induce out-of-control growth, otherwise known as cancer.


Of course, the big upside is that if the process can be understood better, it opens the possibility of treatment for people who've lost limbs, perhaps even organs, to disease or trauma.


A contest seems to exist between researchers, scientists and engineers seeking to repair damaged bodies through cellular alchemy such as this, and those persuing repairs by means of prosthetics or artificial appliances. Here, competition is a good thing; the more sick and injured people can benefit from this arms (and legs) race, the better. But I have to give the edge to the cellular biologists. Artificial legs with built-in radar, so as to scan and mirror movements of the opposing limb, with advanced onboard AI systems give users a great degree of freedom ... and are very cool pieces of engineering. But they're not alive. You can't feel them as you would an actual body part, they can't heal themselves if scratched, and the batteries inevitably run down. Such is not the case with regenerated limbs or body parts made of actual living tissue.


And forget Frankensteinian transplants of body parts. I read recently where a woman who'd received a shotgun blast to the face from a deranged "significant other" was given a face transplant. But she still can't see, and she'll be on meds the rest of her life to supress her immune system so that her body doesn't reject the new tissue. Better if we had a way of regenerating her original face.


Such a thing may not be far away. We've gotten to where we can read the genetic code. Now if we can only learn to write it as well.

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