I’d like to say a few words about one of the hottest and, in my view, most important areas in biomedicine: autophagy, a process crucial to health, disease, and aging. Autophagy research is expanding rapidly.
In autophagy (“self eating”), cells engulf and digest their own macromolecules and organelles. Autophagy serves two functions: providing critical nutrients in times of scarcity, and recycling damaged cellular structures (2009 review, pdf).
It seems that lab animals and human beings fed ad-libitum do too little autophagic recycling. The resulting accumulation of damaged machinery causes a wide range of functional deficits, and accumulation of damaged mitochondria, in particular, increases the production of reactive oxygen species, accelerating further damage.
In a range of organisms, dietary restriction both induces autophagy and results in wide-ranging health benefits, including the extension of healthy lifespans. Blocking autophagy blocks the most important of these effects. Rapamycin induces autophagy and extends lifespan, as does sirtuin-1. Autophagy again appears to be central to these effects. A recent review article examines genetic interventions that indicate “tight connections between autophagy, health span and aging”.
The importance of vigorous autophagy to human lifespan is an inference, but it’s more than just plausible. Diverse results in humans, mice, and C. elegans: they all fit a pattern of effects that stems from a process as old as eukaryotic cells.
Upregulating autophagy has known, wide-ranging benefits, and more are being discovered at a fast pace. You might enjoy exploring the state of current knowledge with Google Scholar (here’s a search).
Let’s see… a July, 2010 opinion from Trends in Molecular Medicine: “Autophagy as a basis for the health-promoting effects of vitamin D”. That’s a new link to another hot topic.