Visceral adipose tissue modulates mammalian longevity.

Caloric restriction (CR) can delay many age-related diseases and extend lifespan, while an increase in adiposity is associated with enhanced disease risk and accelerated aging. Among the various fat depots, the accrual of visceral fat (VF) is a common feature of aging, and has been shown to be the most detrimental on metabolic syndrome of aging in humans. We have previously demonstrated that surgical removal of VF in rats improves insulin action; thus, we set out to determine if VF removal affects longevity. We prospectively studied lifespan in three groups of rats: ad libitum-fed (AL-fed), CR (Fed 60% of AL) and a group of AL-fed rats with selective removal of VF at 5 months of age (VF-removed rats). We demonstrate that compared to AL-fed rats, VF-removed rats had a significant increase in mean (p < 0.001) and maximum lifespan (p < 0.04) and significant reduction in the incidence of severe renal disease (p < 0.01). CR rats demonstrated the greatest mean and maximum lifespan (p < 0.001) and the lowest rate of death as compared to AL-fed rats (0.13). Taken together, these observations provide the most direct evidence to date that a reduction in fat mass, specifically VF, may be one of the possible underlying mechanisms of the anti-aging effect of CR.