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Aging and Lifespan

How Rapamycin Extends Lifespan: Not By Slowing Down Aging

A few years ago, there came the interesting news that rapamycin looked as if it prolonged lifespan in mice. That result is robust; it’s been replicated. Now a large multicenter effort in Germany has looked closely at this effect, and they have many more details about what’s going on.
The big question is: does rapamycin extend lifespan through some general effect on aging, or does it work through a non-aging mechanism (by perhaps suppressing tumor formation)? Now, many people wouldn’t find that much of a distinction – would you like a drug that makes you age more slowly, or would you like one that keeps you from getting cancer? The answer would probably be “Yes”. But it’s a question that very much matters biochemically.
And it turns out that it’s the latter. This new paper does a very careful examination of many phenotypes of aging, on both whole-animal and tissue levels, and finds that rapamycin treatment does not really seem to affect age-related changes. What changes they did see on rapamycin treatment were also present in young mice as well as older ones, making them less likely to be an underlying cause of the effect. They now believe that the compound’s effect on lifespan is entirely, or almost entirely, due to the lower rate of fatal neoplasms.

8 comments on “How Rapamycin Extends Lifespan: Not By Slowing Down Aging”

  1. John Schilling says:

    OK, is there some sort of prize for the most deeply-buried lead in academic publishing that these guys are going for? Rapamycin is (from an admittedly limited sample) 100% effective in preventing tumor formation in middle-aged mice, and the paper is essentially just a list of things Rapamycin doesn’t prevent?
    If this group ever does come up with the immortality pill, or the cure for cancer, I expect the headline will read “purported wonder drug completely fails to cure the common cold”. With buried paragraph about how, because none of the test subjects ever died, they’ve got lots and lots of data about all the colds they caught.

  2. johnnyboy says:

    @1: rapamycin is a known anti-proliferative, and it and other related limus drugs have been tested and used as anti-neoplastic agents. The fact that it had an anti-neoplastic effect in a small subset of mice is not exactly breaking news. Pushing it as such would have been an example of the over-hyping of minor findings that is often derided in this very blog.

  3. D says:

    The new paper does a gat job of listing all the things rapamycin does and doesn’t do. One of the major effects of rapamycin that has been described is improved cognition in old mice. How would this be achieved if rapamycin is solely an anti-neoplastic?

  4. johnnyboy says:

    @3: It’s not. Rapamycin inhibits the mTor pathway, which is involved in many processes, by modulating protein synthesis and breakdown. Rapamycin has multiple effects in many tissue types, in addition to its antiproliferative effects.

  5. Sili says:

    I assume that a lot of impatient nuts have been taking rapamycin for years now.
    Have the sideeffects shown up yet?

  6. Jim D. says:

    Unfortunately it seems like it has strong potential for lung toxicity issues, albeit mainly for people with existing lung issues, along with side effects that will mimic or exacerbate type-II diabetes. Still, for the right patient, it could be useful in life extension baring these other contraindications.

  7. nitrosonium says:

    speaking of mTOR inhibitors…..i have synthesized some novel mTOR inhibitors (seem to be better than sirolimus) but those who were interested have no more money. anyone out there interested??

  8. TNT says:

    Hi! Any suggestions for a science project on this? One that’s a bit advanced? Thanks in advance.

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