Monday October 5 2009
An "elixir of life" remains in the realm of science fiction
The Daily Express claims that a “wonder pill can lengthen your life by 25 years” and that researchers have found the key to the “elixir of life”.
Although the article contains bold claims and a picture of a woman taking a pill, no such pill exists. The research behind this story investigated how a naturally occurring compound called spermidine affected the age-related processes and longevity of yeast, flies, worms, human blood cells and mice.
The laboratory-based study found that spermidine protected cells from certain processes related to ageing and cell damage, increasing the lifespan of the flies, blood cells, yeast and worms. Additional studies in live mice found that cells were protected from particular types of cell damage, but their lifespans were not reported. While the research itself is important, any spermidine pill, as described by the Daily Express, is many years away.
This is at least the second time that the newspaper has reported on a supposed discovery of an elixir of life in recent months.
Where did the story come from?
The study was carried out by Dr Tobias Eisenberg and colleagues from the University of Graz in Austria, alongside medical and academic institutions across Europe. It was funded by the Austrian Science Fund and the European Commission, and published in the peer-reviewed medical journal Nature Cell Biology.
What kind of scientific study was this?
This research investigated the action of a naturally occurring chemical called spermidine in the process of autophagy (the body’s controlled digestion of cells or of damaged parts of cells).
Autophagy is instrumental in recycling old cells to maintain a balance with growth and regeneration. Failures in autophagy are thought to lead to ageing. Cellular concentration of spermidine has been shown to decline with ageing.
The researchers investigated how spermidine affected longevity and various age-related processes in yeast, flies, worms, human cells and mice. To do this, they did the following:
- Applied spermidine to ageing yeast cells.
- Supplemented the diet of the fruit fly (Drosophila melanogaster) and the nematode worm (Caenorhabditis elegans) with spermidine.
- Supplemented the drinking water of mice with spermidine for 200 days.
- Compared the lifespan of human blood cells that were cultured with spermidine and those that were not (the control group).
The researchers also investigated the reverse: the effect that polyamine depletion would have on cells. Biochemical analyses were used to assess the specific effects of spermidine on age-related processes.
What were the results of the study?
Spermidine had a range of effects on the cells and living creatures. It suppressed processes associated with ageing, reduced free radical levels and increased lifespan. The levels of spermidine in the cells increased too (reducing levels are usually associated with increasing age although causality has not been established). In the tests on blood cells, spermidine treatment resulted in 50% of cells surviving to 12 days, compared to only 15% of the control blood cells.
Treated yeasts survived four times as long as untreated cells, while treated fruit flies lived 30% longer than the untreated ones. The lifespan of the worms was extended by 15%. The effect on the lifespan of live mice was not investigated.
Further investigation revealed that the programmed death of cells (apoptosis) was not reduced, but spermidine appeared to protect against the type of cell death that results from more traumatic cell injury (necrosis).
When cells were deprived of spermidine, yeast lifespan was reduced and free radicals accumulated. One theory of ageing (the free radical theory) suggests that it is these entities that accumulate in the body and cause oxidative stress, which leads to ageing.
What interpretations did the researchers draw from these results?
The researchers conclude that they have discovered that levels of spermidine both inside and outside the cell induce autophagy, the failure of which has been implicated in ageing.
What does the NHS Knowledge Service make of this study?
This laboratory-based study has highlighted the important role of the naturally occurring compound spermidine in age-related processes and lifespan. The results of this research, both in cell cultures and mice, may be of great interest to those studying the chemical and biological processes of ageing, and may suggest a possible area for future research.
The Daily Express has suggested that we are a step closer to a “wonder pill that could extend lifespan by up to 25 years”. Even if that were true, this would be only one step forward on a very long journey: this is early research into how a chemical affects mice and cells in a lab, and it may never result in such a simple ‘treatment’ for ageing. According to the Daily Express this is at least the second elixir of life that has been discovered in just a few months (see this previous article on long-life pills).
Even if spermidine has the potential to possible affect ageing, it will take many more years of research including laboratory testing, further cell studies, further animal studies, short-term clinical trials and long-term clinical trials, to establish the safety, benefits, drawbacks and costs of such a treatment.
The Daily Express article mentions other recently reported research that predicts that the majority of the UK’s newborn babies will live to beyond 100. However, this is based on the increase in life expectancy in past years and not specifically on the advent of new treatments.