A New Path to Longevity
By David Stipp January 2012
In mid-2009 a drug called rapamycin was discovered. This drug was found to be able to increase the survival of old lab mice by as much as 1/3 when they were believed to be so ancient that they wouldn’t respond to the medicine. It also increased the average lifespan of female mice by 14% and male mice by 9%. Rapamycin affects an enzyme in all mammals’ bodies called mTOR. The TOR enzyme governs cell growth and acts as a nutrient sensor. When food is abundant, TOR makes the cells in the body increase the production of proteins and divide more. But when food is limited, TOR reduces protein manufacturing and increases autophagy, causing cells to breakdown defective cell parts such as old mitochondria or misshapen proteins. This creates by-products that can later be as energy for the body in recompense for the fewer calorie intake.
It was found in the lab mice that if they always had abundant calories, mTOR would be activated constantly, which accounts for immature organism growth and down the road, accumulation of abnormal proteins and senescent cells as autophagy is inhibited. But if the lab mice had scarcer resources and fewer calories, then mTOR would be inhibited and growth slowed until adequate resources become available. As calorie intake is reduced, autophagy increases and all the malfunctional cell parts are taken in for food, which accounts for healthy body tissue, and healthy body tissue means