Hormesis in aging

Following up on our recent discussions of hormesis, in which mild acute stress protects against severe or chronic stress, here’s a review by Suresh Rattan that discusses the phenomenon in light of aging. Stress resistance and longevity, after all, go hand in hand.

Hormesis in aging is represented by mild stress-induced stimulation of protective mechanisms in cells and organisms resulting in biologically beneficial effects. Single or multiple exposure to low doses of otherwise harmful agents, such as irradiation, food limitation, heat stress, hypergravity, reactive oxygen species and other free radicals have a variety of anti-aging and longevity-extending hormetic effects. Detailed molecular mechanisms that bring about the hormetic effects are being increasingly understood, and comprise a cascade of stress response and other pathways of maintenance and repair. Although the extent of immediate hormetic effects after exposure to a particular stress may only be moderate, the chain of events following initial hormesis leads to biologically amplified effects that are much larger, synergistic and pleiotropic. … Healthy aging may be achieved by hormesis through mild and periodic, but not severe or chronic, physical and mental challenges, and by the use of nutritional hormesis incorporating mild stress-inducing molecules called hormetins. The established scientific foundations of hormesis are ready to pave the way for new and effective approaches in aging research and intervention.

The discussion is quite broad, with appropriate emphasis given to classical examples of hormesis (radiation, thermal stress, and the emerging idea that calorie restriction is a form of hormetic stress) as well as forays into unusual stresses such as hypergravity.

At the end of the abstract he mentions “hormetins” — this is a fairly new term that has yet to gain substantial traction in the field, referring to compounds that confer stress resistance and possibly increased longevity by inducing low levels of stress themselves. As we learned recently, resveratrol may be among them.