What doesn’t kill you may make you live longer

Many people believe that free radicals, the sometimes-toxic molecules produced by our bodies as we process oxygen, are the culprit behind aging. Yet a number of studies in recent years have produced evidence that the opposite may be true. Now, researchers at McGill University have taken this finding a step further by showing how free radicals promote longevity in an experimental model organism, the roundworm C. elegans . Surprisingly, the team discovered that free radicals - also known as oxidants - act on a molecular mechanism that, in other circumstances, tells a cell to kill itself. Programmed cell death, or apoptosis, is a process by which damaged cells commit suicide in a variety of situations: to avoid becoming cancerous, to avoid inducing auto-immune disease, or to kill off viruses that have invaded the cell. The main molecular mechanism by which this happens is well conserved in all animals, but was first discovered in C. elegans - a discovery that resulted in a Nobel Prize. The McGill researchers found that this same mechanism, when stimulated in the right way by free radicals, actually reinforces the cell's defenses and increases its lifespan.