Friday, August 26, 2005

Has the social security crisis been averted? Klotho protein for aging

Life-Lengthening Hormone Found in Mouse Research

We can extend the lifespan of mice 20% by injecting a peptide produced by the Klotho gene:
The discovery was triggered by a study Kuro-o and his colleagues published in 1997. That study identified a gene in mice that, when damaged, caused the animals to experience all the hallmarks of aging in humans -- hardening of the arteries, thinning bones, withered skin, weak lungs -- and to die prematurely. They dubbed the gene Klotho, for the Greek goddess who spins the thread of life.

Suspecting the gene may play a role in regulating life span, Kuro-o and his colleagues genetically engineered mice with overactive Klotho genes. In the latest experiments, they found that these animals lived an average of 20 to 30 percent longer than normal -- 2.4 to 2.6 years vs. a normal life span of about two years -- without any signs of ill effects, according to the new report.

'The extension of life span is widely accepted as a reliable marker for the suppression of aging,' Kuro-o said. 'This shows the Klotho gene regulates aging.'

The researchers then identified a small protein component, called a peptide, that the gene produces and found it circulating in the animals' blood at double the normal level.

After isolating and purifying the substance and reproducing it through genetic engineering techniques, the researchers injected the substance into normal mice. Tests on those animals, combined with experiments involving cells in the laboratory, indicate that the substance modulates a crucial biological pathway involved in an array of basic metabolic functions that has become the focus of aging research in recent years.

'It's a pathway that has been conserved by evolution that has been found to play a key role in regulating life span for flies, worms, mice and probably humans,' Kuro-o said.

Studies, for example, suggest that damping down this pathway -- known as the insulin/insulin-like growth factor-1 signaling pathway -- may be the mechanism that extends longevity in animals that are fed an ultra-low-calorie diet.
This may be very important for persons with the very rare disease of Progeria. (Yes, this has occurred to others.)

Would a purified protein of this sort slow aging in humans and thus avert the social security crisis? Ahh, there's the catch. Given the advantages to human communities of long-lived women, and the the extent to which males have mostly female genomes, I'd guess we find three things:

- It doesn't work on females -- we'll find their Klotho peptide levels are already pretty high.
- It does add 5 years of life to newborn males if given for the entire lifespan, but has no significant benefit for middle-aged males.
- It has a big impact on a subset of the the population that turns out to have a faster basal aging rate (maybe as high as 30% of our population).

The third of these might indeed avert the "social security crisis". (We already know how to avert it really -- more selective immigration policies (wealthier immigrants -- follow Canada's model) and making payouts more progressive.)

1 comment:

JGF said...

Charming! From the above I can see I'm getting comment spam now. I guess spammers have enough registered accounts with blogger to do this.

I've had to enable the weird word verification process for comments. Annoying for sighted persons, very bad for those needing screen readers.