BREATHE member, Dr. Russ Hepple, was recently awarded a $2.8M R01 grant from the National Institute on Aging to study “Linking kynurenine accumulation and the AHR pathway to exacerbated aging.” Physical frailty can lead to a loss of independence and increased risk of mortality in the elderly. Interestingly, multiple studies have found a strong association between elevated circulating levels of tryptophan metabolites, particularly kynurenine, and an increased risk of frailty; however, the mechanisms involved are unknown. Notably, tryptophan metabolites support the development of the central and enteric nervous systems, and their dysregulation can lead to many neurologic and psychiatric disorders. In this new R01, Dr. Hepple will determine if elevated kynurenine levels accelerate muscle aging in mice, thus leading to physical frailty, and if a new intervention protects the animals from the effects of aging. These studies have the potential to help scientists better understand age-associated decline in physical function and may eventually lead to therapies that mitigate the risk of frailty in elderly people. Congrats, Dr. Hepple!