Sympathetic Stupid

Wednesday, September 07, 2005

Miracle Mouse Minnie?

A new era in medicine? I'm surprised this hasn't had more publicity, as it appears one of the most amazing scientific achievements ever.

'Miracle mouse' can grow back lost limbs (The Times)
Out on a Limb Tissue regeneration should be treated cautiously (The Times Of India)

"Scientists have created a 'miracle mouse' that can regenerate amputated limbs or badly damaged organs..."
"...when cells from the test mouse are injected into ordinary mice, they too acquire the ability to regenerate."
"...the prospect that humans could one day be given the ability to regenerate lost or damaged organs..."

This is computer game, science fiction stuff. For anyone who's ever wondered wy their D&D character heals when they rest overnight, this is obviously the answer. The only organ that didn't regenerate was the brain, so it's not all good news, but being able to regrow a heart or lung or arm or toe or liver is pretty impressive.

Looking deeper, it's actually not quite as farfetched as it sounds. We can regrow our liver, and of course skin. And many fish and amphibians can regrow internal organs. So the biological pathways are in place. It's interesting that "the MRL mouse seems to have a higher rate of cell division", which seems to be the key. The hypothesis is that this could also confer greater longevity. Seems to me it could also result in higher cancer rates, but that's pure speculation right now.

Now, there's huge ethical problems. Most of us can ignore that fact that these mice were being cut up and tortured to see if they could recover. There'll be bigger conundrums with making this useful in humans. The way ordinary mice gained regenerative powers was through having foetal liver cells from these presumably genetically engineered mice injected into them. So to do that in humans, you'll probably need to create a foetus, mess with its genes, harvest some liver cells and kill the foetus, if I understand the process correctly.

And then there's the broader problem, as explained in the Times Of India article. "Why did the ability devolve in the first place? Was there a survival benefit in delimiting its use? Could its reintroduction bring about mutations?" And the question underlying genetic engineering; is it right to play God? Some of these questions are quite answerable; it seems likely that longevity was actually detrimental in the Good Old Days. If no-one had enough food, what's the point keeping you alive after you've stopped reproducing? From an evolutionary standpoint, the lifespan of primitive man should logically have been around 30-35 years, enough time to pop out a brood of babies and have at least two survive to propagate the species, but not enough time to drain resources. That probably answers two of those questions. In the Western World, these things are generally not a problem. In the Third World, that's nowhere near true.

Which leads to the bigger issue, of whether creating 'supermen' who can regenerate would result in the human race splintering into two separate species, the supermen and the underclass; if you like, it's the Time Machine scenario. Given the inequality between rich and poor, and the fact that this science is guaranteed to be expensive, it's hard to see that not happening.