Effects of Exhaustive Aerobic Exercise on Tryptophan-Kynurenine Metabolism in Trained Athletes

Abstract

Exhaustive exercise can cause a transient depression of immune function. Data indicate significant effects of immune activation cascades on the biochemistry of monoamines and amino acids such as tryptophan. Tryptophan can be metabolized through different pathways, a major route being the kynurenine pathway, which is often systemically up-regulated when the immune response is activated. The present study was undertaken to examine the effect of exhaustive aerobic exercise on biomarkers of immune activation and tryptophan metabolism in trained athletes. After a standardized breakfast 2 h prior to exercise, 33 trained athletes (17 women, 16 men) performed an incremental cycle ergometer exercise test at 60 rpm until exhaustion. After a 20 min rest phase, the participants performed a 20 min maximal time-trial on a cycle ergometer (RBM Cyclus 2, Germany). During the test, cyclists were strongly encouraged to choose a maximal pedalling rate that could be maintained for the respective test duration. Serum concentrations of amino acids tryptophan, kynurenine, phenylalanine, and tyrosine were determined by HPLC and immune system biomarker neopterin by ELISA at rest and immediately post exercise. Intense exercise was associated with a strong increase in neopterin concentrations (p<0.001), indicating increased immune activation following intense exercise. Exhaustive exercise significantly reduced tryptophan concentrations by 12% (p<0.001) and increased kynurenine levels by 6% (p = 0.022). Also phenylalanine to tyrosine ratios were lower after exercise as compared with baseline (p<0.001). The kynurenine to tryptophan ratio correlated with neopterin (r = 0.560, p<0.01). Thus, increased tryptophan catabolism by indoleamine 2,3-dioxygenase appears likely. Peak oxygen uptake correlated with baseline tryptophan and kynurenine concentrations (r = 0.562 and r = 0.511, respectively, both p<0.01). Findings demonstrate that exhaustive aerobic exercise is associated with increased immune activation and alterations in monoamine metabolism in trained athletes which may play a role in the regulation of mood and cognitive processes.

Probiotic Supplements Beneficially Affect Tryptophan–Kynurenine Metabolism and Reduce the Incidence of Upper Respiratory Tract Infections in Trained Athletes: A Randomized, Double-Blinded, Placebo-Controlled Trial

“…The essential amino acid Trp is not only a precursor of the serotonin biosynthesis pathway but is also the key element for the formation of the energy carrier and coenzyme nicotinamide-adenine-dinucleotide NAD and its reduced form NADH via the so-called kynurenine (Kyn) pathway [13,14]. Recently, exhaustive aerobic exercise in athletes was reported to significantly impact on Trp–Kyn metabolism [15]. Results indicate an involvement of IDO-1 activation in enhanced Trp catabolism and Kyn production following demanding exercise [15].…”

“…Recently, exhaustive aerobic exercise in athletes was reported to significantly impact on Trp–Kyn metabolism [15]. Results indicate an involvement of IDO-1 activation in enhanced Trp catabolism and Kyn production following demanding exercise [15]. The close association of Trp metabolites with neuropsychopharmacologically relevant metabolites may have special consequences for athletes since it influences immunosurveillance and the development of infections as well training adherence because of disturbed neurotransmitter biochemistry [16].…”

Using neopterin to monitor stress in hypoxic and normoxic repeated sprint training in rugby players

“…While neopterin and total neopterin have been used to assess stresses associated with rugby (Lindsay et al, 2015;Lindsay et al, 2016), exhaustive cycling (Strasser et al, 2016), and body building (Lindsay et al, 2014), this is the first study we are aware of that has investigated its use in repeated sprint training with and without hypoxia. The results of the present study demonstrate large variability in individual neopterin and total neopterin responses to repeated sprint training in both normoxic and hypoxic groups (Figure.…”

“…The immediate rise in neopterin and total neopterin levels help detect short-term stress in sports. For example, these markers increase following exhaustive aerobic exercise (Strasser et al, 2016), or muscle damage sustained during strenuous rugby games (Lindsay et al, 2016). Furthermore, the acute difference between a player's resting and their immediate-post game levels of neopterin and total neopterin vary widely depending on the extent of the individual player's recovery (Lindsay, Lewis, Gill, Gieseg, & Draper, 2015).…”

Physical Activity and Diet Shape the Immune System during Aging

“…A supply of certain nutrients and bioactive compounds (such as antioxidants, n-3 PUFAs, or probiotics) can suppress ("−") IDO activity and slow down Th1-type immune activation cascades. On the other hand, physical exercise stimulates the ("+") induction of IDO, which is associated with an accelerated tryptophan breakdown and an increased kynurenine/tryptophan ratio [76]. Kynurenine metabolites can affect the brain and several other organs in peripheral tissues, where they induce local and systemic adaptations (see the main text for a description) [67].…”