Booster Shots

Oddities, musings and news from the health world

« Previous Post | Booster Shots Home | Next Post »

Sure, mice on rapamycin may get some extra time…*

July 9, 2009 | 10:34 am

Even the hint -- from an animal study, no less -- that a specific drug may eventually help humans extend lifespan is enough to generate considerable popular excitement, presumably among those who have an interest in living longer. But if it's longevity you want, suppressing the immune system may not be the best way to go. That's what the drug in question, rapamycin, does.

For one thing, this suppression does tend to increase the risk of disease. An undesirable side effect by anyone's standards.

Rapamycin, an antibiotic commonly given to prevent rejection of organ transplants, was given to old mice in a recent study and, yes, the animals lived longer. Lifespan was increased up to 14% for female rodents (not to belabor the point, but it's worth repeating that the study was on, yes, rodents) and up to 9% for male rodents. *

Now, more on rapamycin.

The National Cancer Institute defines it as: "An antibiotic that blocks a protein involved in cell division and inhibits the growth and function of certain T cells of the immune system involved in the body's rejection of foreign tissues and organs. It is a type of immunosuppressant and a type of serine/threonine kinase inhibitor. Rapamycin is now called sirolimus." 

More on sirolimus from, which points out that the drug can increase the risk of certain types of cancer -- lymphoma and skin cancer, for example.

Here's a summary of the new research, published Wednesday in the journal Nature. It states: "Rapamycin may extend lifespan by postponing death from cancer, by retarding mechanisms of ageing, or both."

That's heady stuff. Here's a bit more context, in a more accessible version, from And a blog post from the site pointing out just where the word "mice" first appeared in various media reports.

As a Forbes story clarifies, the significance here is actually what the research tells us about the biology of aging. There's a long way to go between one finding about a signaling pathway in the body and practical effects in people. A very long way.

But, of course, that doesn't mean you shouldn't try to get this antibiotic and take it as an insurance policy. Mega doses, naturally, just to be on the safe side. 

-- Tami Dennis

* An earlier version of this story said the mice were all of the same type. Not so, as Mr. Miller (see comment below) was kind enough to point out.

Post a comment
If you are under 13 years of age you may read this message board, but you may not participate.
Here are the full legal terms you agree to by using this comment form.

Comments are moderated, and will not appear until they've been approved.

If you have a TypeKey or TypePad account, please Sign In

Comments (5)

For people with lupus, the side effect of immune suppression would actually be welcome.

Since most major discoveries come from experimentation that begins with lab animals (usually mice) there is legitimate reason to hope this will lead to treatments that help humans to live longer. After all, penicillin first worked in a petri dish on mold. Eventually it became quite useful. Of course, no one will make you take it if it works....

Ms. Dennis:

I enjoyed your story, but wanted to point out an error in it - you say that "The mice were all of the same type; They weren't even a genetically diverse population of rodents." Actually, as pointed out in the original Nature article and in many of the press reports, one of the nice parts of the study design is that this set of experiments (unlike most other mouse studies) used genetically heterogeneous mice. We did this on purpose, to avoid the criticism that a drug that worked would only work on one single kind of mice.

I agree that we're still a long way from having something that works on people. But this might be a step in that direction, if we're lucky.

Rich Miller

The point of the study is to elucidate a fundamental biomolecular pathway, knowledge of which will result in an understanding of the aging process and giving us a target for reversing it. No scientist is suggesting suppressing the immune system to increase lifespan ... after, most rodent work is performed in a sterile environment not applicable to real life. But once scientists understand how rapamycin increases longevity, a drug targeted for that 'how' can be produced to increase lifespan without side effects.

James Sonne

This may seem a bit off the wall, but it is germane to the background behind all this.

As our understanding of the mechanisms of aging become known, and as our ability to escape their effect thus becomes possible, our understanding of the chemical basis of life, consciousness, free will, pain, pleasure, and the desire to extend life itself will likely also become known. The tragedy that faces us in the not-too-distant future isn't that we won't find a cure for aging, but that we will find it and no longer perceive any compelling reason to use it.. What a sad and funny thing that would be. On the other hand, maybe we would want to stick around just to savor it!


The Latest | news as it happens

Recent Posts
test |  March 15, 2011, 4:00 pm »
Booster Shots has moved |  July 12, 2010, 6:02 pm »