Characterization of Redox Environment and Tryptophan Catabolism through Kynurenine Pathway in Military Divers’ and Swimmers’ Serum Samples

Abstract

Endurance and resistance exercises, alone or in combination, induce metabolic changes that affect tryptophan (Trp) catabolism. The kynurenine pathway (KP) is the main route of Trp degradation, and it is modulated by the inflammatory and redox environments. Previous studies have shown that KP metabolites work as myokines that mediate the positive systemic effects related to exercise. However, it is poorly understood how different exercise modalities and intensities impact the KP. The aim of this study was to characterize the effect of two different exercise modalities, military diving and swimming, on the KP and the redox environment. A total of 34 healthy men from the Mexican Navy were included in the study, 20 divers and 14 swimmers, who started and stayed in military training consistently during the six months of the study; 12 Mexican men without fitness training were used as the control group. Physical fitness was determined at the beginning and after 6 months of training; criteria included body composition; serum levels of Trp, kynurenine (KYN), kynurenic acid (KYNA) and 3-hydroxykynurenine (3-HK); the glutathione ratio (GSH/GSSG); and malondialdehyde (MDA).. Results showed a significant loss of body fat in both the diver and swimmer groups. Compared with the control group, divers showed a decrease in Trp and 3-HK levels, but no changes were observed in the KYN/Trp, KYNA/Trp or 3-HK/Trp ratios, while swimmers showed a decrease in KYN levels and an increase in the KYNA and 3-HK levels. Additionally, divers showed a decrease in the GSH/GSSG ratio and an increase in MDA levels, in contrast to the swimmers, who showed a decrease in MDA levels and an increase in GSH/GSSG levels. Our findings suggest a differential shift in the KP and redox environment induced by diving and swimming. Swimming promotes an antioxidant environment and a peripheral overactivation of the KP.

Inhibition ofhaao-1enhances oxidative stress response by activating hormetic redox signaling inC. elegans

“…There has been a lot of controversy related to the pro-oxidant or antioxidant properties of several metabolites in the kynurenine pathway and consequently, about their effects in the cell and potential roles in many redox-related processes(González Esquivel et al, 2017; Massudi et al, 2012; Sánchez Chapul et al, 2022; Sas et al, 2018; Wigner et al, 2017; Zhuravlev et al, 2016). However, recent evidence shows that the redox properties of many of these metabolites are dependent on the in vivo environment, particularly, the presence of other molecules around it.…”

Crosstalk between Exercise-Derived Endocannabinoidome and Kynurenines: Potential Target Therapies for Obesity and Depression Symptoms

“…It is noteworthy that, although these mechanisms have been demonstrated in animal models and in healthy humans, it could not be proven that physical exercise could induce long-lasting changes in the peripheral blood levels of KYNA; this was the case in a 12-week exercise intervention test performed among depressed patients [67], as well as in testing samples of the sweat of adult patients with chronic back pain following 28 days of training [68]. However, following 6 months of different swimming intensities, a peripheral overactivation of the KP has been observed, leading to a decrease in KYN levels and an increase in circulating KYNA and 3-HK levels [69].…”