Re: Re: Human Cell Lifespan Extended

CurtAdams (
Thu, 15 Jan 1998 14:18:04 EST

In a message dated 1/15/98 10:57:25 AM, wrote:

>What about finding single treatment drugs that will do a quick flood of the
>with telomerase to rebuild the telomeres, and then flush the drugs from the
>system. With a short term exposure for rebuilding telomeres, long term
>on cancer probabilty would be low.

No, not so simple. Just lengthening the telomeres gives every pre-cancerous
but still telomere-limited 2^(extra divisions from lengthening) times as
many tries to mutate past the telomerase limitation. In addition, just the
extra divisions permitted may be enough for the cancer to kill the host.
It's a good bet that the existence of telomerase and the number of
permitted by the existing telomere lengths are, to a first approximation,
optimal for lifespan. If, say 5 extra divisions improved average lifespan,
the germline telomeres would probably evolve to be that much longer.
Likewise for shorter telomeres.

Better, for that kind of thing, would be to target the telomerase to tissues
where the risk of fatal cancer is relatively low (e.g. skin) or where the
hazards of senescence are particularly high (e.g. blood stem cells).

One general approach would be to take out crypt cells (cells from tissue that
divide to replace those that die), proof them for pre-cancerous mutation,
telomere-lengthen the "clean" ones, and then put them back without telomerase.