Autophagy seems to be the topic of the week, and here's another example of research demonstrating enhanced longevity in laboratory animals through increased autophagy:
Here, we report that administration of spermidine, a natural polyamine whose intracellular concentration declines during human ageing, markedly extended the lifespan of yeast, flies and worms, and human immune cells. In addition, spermidine administration potently inhibited oxidative stress in ageing mice [and] led to significant upregulation of various autophagy-related transcripts, triggering autophagy in yeast, flies, worms and human cells.
Those of you who like your research a little more preprocessed than the original papers will no doubt prefer this article from the science press:
It seems that spermidine exerts its influence at the level of the cell's mechanism for dealing with damaged internal components. Throughout a cell's life, proteins and other molecules become damaged by exposure to environmental factors such as UV light or oxidants. This debris is swept up and deposited into a biochemical recycling bin. However, as cells age this clean-up process, called autophagy, becomes less efficient and ultimately the accumulation of this waste causes the cell to trigger its own suicide.
Autophagy is ultimately controlled by genes being switched on and off. It appears that spermidine inhibits a protein in the cell's nucleus that is involved with controlling the genes for autophagy.
Richard Faragher, an expert on cellular ageing at the University of Brighton in the UK, says that the new work 'is interesting because it adds to the growing body of data suggesting that ageing is caused by a general failure of recycling.'
You might compare this with another recent attempt at increasing autophagy in mammals, which also showed positive changes in biochemistry. While assessing end results is comparatively rapid in short-lived worms and flies, it takes much more time to establish that a mechanism also holds in mammals. Mouse or rat life span studies take a good number of years to complete, which is why we'll probably be waiting a while longer to learn to what degree their lives are extended by methods of boosting autophagy.
Eisenberg, T., Knauer, H., Schauer, A., Büttner, S., Ruckenstuhl, C., Carmona-Gutierrez, D., Ring, J., Schroeder, S., Magnes, C., Antonacci, L., Fussi, H., Deszcz, L., Hartl, R., Schraml, E., Criollo, A., Megalou, E., Weiskopf, D., Laun, P., Heeren, G., Breitenbach, M., Grubeck-Loebenstein, B., Herker, E., Fahrenkrog, B., Fröhlich, K., Sinner, F., Tavernarakis, N., Minois, N., Kroemer, G., & Madeo, F. (2009). Induction of autophagy by spermidine promotes longevity Nature Cell Biology DOI: 10.1038/ncb1975