Imagine a smart meter in your house that keeps an eye on electricity. When power runs low, it automatically shuts off unnecessary appliances to avoid overuse. Our cells have a similar sensor. It detects when a cell is short on fuel and switches it into economy mode: the cell starts spending less and storing more. With age, this sensor works less well, and cells stop economizing properly.
Scientists have found a drug that presses the button on this sensor. It is called MK-8722. It was given to tiny worms and elderly mice. The worms that received the drug lived 13% longer than usual. In mice roughly equivalent to 60 human years old, the drug helped prevent excess weight gain and maintain normal blood sugar levels.
The drug also helped mice maintain a clear daily metabolic rhythm. Normally, with age, the body stops understanding when it is day and when it is night, and metabolism gets out of sync. In mice on the drug, this rhythm stayed the same as in youth. This means the pill mimics the effect of fasting without forcing the animal to give up food.
It is still unclear whether taking such a drug long-term is safe, because in mice the heart and kidneys enlarged slightly. But if this problem can be solved, perhaps in the future there will be pills that help people age more slowly.
Lithocholic acid, whose levels rose in mice on MK-8722, was recently recognized as a powerful geroprotector: giving it to old mice reproduced many of the effects of calorie restriction and extended lifespan.
In Peter Watts's novel Blindsight, vampires have a super-efficient metabolism that lets them survive on minimal resources. AMPK activation, as in this work, is a step toward similar metabolic thrift, though without the vampire genes.
Not published on arXiv. Here are its page, the PDF and the formalization: you can check it yourself, not only read our account.