The role of kynurenine pathway metabolites in the development of frailty in older adults

Frailty is the main geriatric syndrome, which is closely associated with agerelated diseases and aging in general. Being considered the main pathogenetic mechanism of aging, low-grade chronic inflammation potentially contributes to increased degradation of the essential amino acid tryptophan through the kynurenine pathway. Active metabolites of the kynurenine pathway, when accumulated, realize their immunomodulatory, pro-inflammatory and cytotoxic properties, thereby supporting and enhancing the aging process. Over the past decade, data have been collected on the role of an unbalanced kynurenine pathway in the pathogenesis of frailty and age-related diseases. This review summarizes clinical and experimental data on the importance of kynurenine pathway analysis as a valuable tool for risk stratification and prognosis of frailty and age-related diseases.