Finding Commonalities in the Response to Different Calorie Restriction Mimetic Drugs
Calorie restriction mimetic drugs reproduce some (usually small) fraction of the beneficial metabolic changes that take place with a reduced calorie intake. An increase in the efficiency of the cellular maintenance processes of autophagy appears to be the crucial point. Researchers here report on their assessment of the alterations produced by the small number of calorie restriction mimetics with robust evidence to slow aging and extend life in mice. This part of the research field seems quite capable of generating any number of treatments that will likely work in humans, but unfortunately from what we know of the effects of calorie restriction, this class of therapy is unlikely to produce a large increase in life span in our species. Short-lived species exhibit a much greater extension of life in response to these metabolic manipulation strategies than is the case in long-lived species. This makes sense from an evolutionary perspective: if the calorie restriction response exists because it helps individuals to survive a seasonal famine to reproduce in later times of plenty, then short-lived species will evolve a much greater plasticity of life span. A season is a much larger fraction of the life span of a mouse than it is of a human.
The pace of aging can be delayed by mutations, dietary manipulations, and drugs, yet the metabolic mechanisms underlying longevity interventions remain poorly understood. Here we present a multi-tissue metabolomic analysis of male UM-HET3 mice treated from 4 to 12 months of age with five validated longevity interventions: rapamycin, acarbose, 17α-estradiol, canagliflozin, or caloric restriction. Using a feature-stabilized XGBoost pipeline applied to seven tissues, we show that metabolomic profiles can identify treated mice as likely recipients of a lifespan-extending intervention well before survival differences emerge. A leave-one-intervention-out procedure confirmed that models trained on any four interventions successfully classified mice from a fifth, unseen intervention, implying shared metabolic alterations across mechanistically distinct treatments.
The most influential metabolites - defined as the minimum set explaining 50% of cumulative model gain - differed substantially across tissues. Only ergothioneine, a dietary antioxidant, ranked highly in more than two tissues: it was elevated by all five interventions in plasma and brain, and by four of five in muscle. Enrichment analyses further identified coordinated remodeling of lipid classes in plasma, perigonadal fat, and kidney. These findings reveal tissue-specific metabolic reprogramming shared across mechanistically distinct longevity interventions and, pending validation against interventions that do not extend lifespan, suggest a path toward metabolomic screening of candidate anti-aging drugs.