I should point out some thoughts from Randall Parker on the topic of that recent research implicating Wnt in the failing capacity of aging stem cells:

Rando previously discovered [that] old stem cells will act younger if exposed to younger blood. That's very troubling news for efforts to develop rejuvenating cell therapies. If the whole body is full of chemical signals that suppress growth then just replacing older stem cells with younger stem cells won't yield as much increase in healing and repair as our aging bodies need.

...

Another research group has just discovered that Wnt is able to suppress mouse stem cell activity because as mice age their bodies make less of another protein called klotho. Well, klotho restrains Wnt and the absence of klotho causes Wnt to suppress stem cell division. ... You might think hey, why not deliver klotho hormone replacement therapy to slow or reverse cellular aging? Good question. Let me put the question another way: Why does klotho production decline with age? Is it just due to accumulation of damage to klotho-making machinery? My guess: the decline of klotho happens in order to reduce the risk of cancer. As cells age they accumulate mutations that could become cancerous. By slowing cell division by reducing klotho the body reduces healing but on average that reduction in healing becomes a net benefit due to avoided cancer.

It's a good educated guess - a number of important mechanisms involved in growth, repair and metabolism in mammals have evolved to a balance between aging and cancer resistance. Simply turning the dial is not a satisfactory solution; you'll either get more aging or more cancer. Solutions at that level of biochemical and genetic engineering have to be smarter - and more complex.

That added level of complexity is one fundamental reason for supporting biomolecular repair research like SENS instead. Don't attempt to change the system, our vastly complex human metabolism, but rather learn how to clean up after it. Repairing the damage and reversing the changes of aging at the level of cells and macromolecules is a much less onerous task that reengineering human biology - while still being a challenge of billions of dollars and tens of years - but one that can bring far greater near-term benefits to health and longevity.

Technorati tags: aging, biotechnology, medical+research, SENS

Posted by Reason at August 14, 2007 9:39 PM | TrackBack (0)