Longevity as Housekeeping and a Role for Bile Acids
Better maintenance means a longer life, as illustrated by the importance of autophagy in calorie restriction (CR). Researchers are now branching out beyond CR to find other ways of influencing metabolism to better maintain cells: "The conserved insulin-signaling pathway has drawn a significant amount of attention over the past few years as a major lifespan determining signaling network. In many systems, impairing this pathway impedes the ability of caloric restriction (CR) to enhance lifespan, suggesting that nutrient sensing is key to CR. ... the Titorenko laboratory [tested] the hypothesis that networks exist within cells that are not inducible, but act constitutively to extend the lifespan of cells regardless of nutrient availability ... [the study] presents an original screen designed to isolate molecules that further lengthen the life span of yeast under calorie restriction rather than imitating this effect. ... Among the chemical compounds identified, the authors focus on one group representing 6 bile acids compounds, the most efficient of them being lithocholic acid (LCA). Bile acids are mildly toxic oxidized derivatives of cholesterol that play important roles in lipid uptake by the intestine."
Link: http://www.impactaging.com/papers/v2/n7/full/100173.html