Saturday, September 28, 2013

Ibuprofen unlikely to extend life

The Daily Mirror today reports that, “taking ibuprofen every day could extend your life by up to 12 YEARS”. The Daily Express also has a similar front page headline, while the Mail Online suggests that these extra years would be of “good quality life”.
If you read these headlines and felt sceptical, you’d be right to do so.
The news has been extrapolated to humans, based on research in yeast, microscopic worms and fruit flies. These organisms are often used in longevity research due to their naturally short lifespans – even the longest-lived among them is measured in days, not decades. 

However, if a chemical does extend lifespan in these relatively simple organisms, this is not a guarantee that it will do the same in more complex organisms, such as mammals. We also have no idea whether any extension of life would be of “good quality”.
Even in the fruit flies, the effect was more complicated than in yeast or worms. Ibuprofen increased the flies’ average lifespan, but actually reduced the maximum lifespan in male flies.
We’re definitely not at a stage where taking ibuprofen every day could be recommended as a way to extend your lifespan. While some people might think “what harm can it do?" and "it might do some good”, ibuprofen is not risk-free. As with most drugs, ibuprofen can cause side effects, including gastrointestinal bleeding.

Where did the story come from?

The study was carried out by researchers from the Buck Institute for Research on Aging, and universities in the US and Russia. It was funded by the US National Institutes of Health and National Science Foundation.
The study was published in the peer-reviewed, open access journal PLOS Genetics.
The newspapers’ headlines are unwarranted over-extrapolations of this animal and laboratory research. Most later clarified that the research was in yeast, worms and flies – but read in isolation, the headlines are misleading.
This seems an irresponsible approach, given the potential harm that could result from people taking a cheap and readily-available drug unnecessarily.


What kind of research was this?

This was an animal and laboratory study looking at whether ibuprofen increases lifespan in flies, worms and yeast.
The researchers say that ibuprofen has been associated with a reduction in the risk of some age-related problems such as Alzheimer’s disease and Parkinson’s disease. However, whether it also has an effect on lifespan is unknown.
The organisms used in this study are often used in studies of lifespan, as their lives are short. This means that researchers can quickly find out if a chemical affects lifespan. If they find the same effect on lifespan in the multiple organisms tested, this suggests that the chemical is affecting a system that has been evolutionarily “conserved” across different organisms. This makes it more likely that the effect may also apply to other, untested, organisms.
However, flies, worms and yeast are relatively simple organisms, and things that affect their lifespans may not have the same impact on more complex organisms such as mammals. For example, while a chemical might double lifespan in a yeast, even if it also has an effect on lifespan in mice, it would be unlikely to have as dramatic an effect.
The researchers say that getting from chemicals that show promise in yeast and other organisms to drugs that are effective and safe in humans is a “significant hurdle”. For this reason, they wanted to look at a drug that was already used in humans, as they are already known to be safe enough for human use.

What did the research involve?

The researchers tested the effects of ibuprofen on one type of yeast, one type of microscopic worm, and fruit flies. In each case they exposed one group of yeast/worms/flies to ibuprofen and another group was not exposed (controls). They measured how long each group lived to see if it differed.
For yeast and worms, exposing them to ibuprofen involved growing them in a solution containing the drug. For yeast, the study looked at how long they were able to keep dividing to produce new yeast cells – a standard measure of their “active” lifespan. For flies, this involved feeding them with a solution that included ibuprofen. The organisms were grown in standard conditions, to make sure that the only thing that differed between them was whether or not they received ibuprofen.
The researchers then carried out a wide range of detailed experiments to determine how ibuprofen was having an effect.

What were the basic results?

The researchers found that yeast exposed to ibuprofen lived 17% longer on average than they did without it. Worms exposed to ibuprofen throughout their lives lived about 20 days, compared to about 18 days on average without ibuprofen. The researchers said that the levels of ibuprofen that extended the lifespan of worms and yeast were in the range of levels reached in people taking ibuprofen at typical doses.
In female fruit flies, ibuprofen extended the average lifespan and also the maximum lifespan. In male fruit flies, ibuprofen extended the average lifespan but, oddly, reduced the maximum lifespan. This meant that the shorter-lived flies were living longer with ibuprofen, but the longest-lived flies were not living as long.
The researchers found that ibuprofen seemed to be having its effect by reducing uptake of the amino acid tryptophan by cells.