U Cambridge biogerontologist Aubrey de Grey has just delivered a presentation to the Fifth Alcor Conference on Extreme Life Extension. The conference proceedings are not online but an abstract of Aubrey's presentation is very intriguing:
Cancer: why it is now the main barrier to extreme life extension, and a revolutionary new approach to defeating it indefinitely
The genomic instability that underlies cancer makes it enormously harder to combat indefinitely than any other aspect of aging. Its only clear-cut "Achilles heel" is the absolute need to stabilise telomeres (usually with telomerase); if this can be prevented with total certainty by deleting (not just suppressing) a vital gene, cancer will be prevented. However, many of our normal cells need telomerase for their normal function. I will explain why existing anti-cancer approaches are unlikely ever to postpone cancer by more than a decade or two, and then present a radical, feasible solution, involving the periodic re-seeding of our various stem cell pools with cells whose telomeres have been re-lengthened ex vivo.
Adult stem cells are considered by some researchers to be a major source of cancer. Adult stem cells divide much more than most other cell types. Therefore they accumulate more damage from errors in replication. At the same time, since they do divide (they are mitotic in biological terms) the settings of their genetic switches are closer than the settings of post-mitotic (ie cells that never divide) cell types to the settings that allow cancers to divide without control.
The replenishment of aged adult stem cells with younger adult stem cells would serve multiple purposes. First, the youthful adult stem cell replacements would be more vigorous and hence would serve as better sources of replacement cells when fully differentiated cells die. Also, I'm guessing that Aubrey is arguing that the replacement stem cells would have fewer genetic defects and longer telomeres and hence be less prone to become cancer cells.
For a general scientific discussion of aging also see Aubrey de Grey's book The Mitochondrial Free Radical Theory of Aging.
Update: On a related subject see this report of the work of Stanford biological chemist Eric Kool on a newer faster method to elongate telomeres.
|Share |||Randall Parker, 2002 November 18 02:40 PM Aging Reversal|