Tryptophan recovery index as a new biomarker for fitness

Authors

  • Alexander Pichler Division of General Anesthesiology, Emergency - and Intensive Care Medicine, Medical University of Graz, Graz, Austria https://orcid.org/0000-0001-7886-6523
  • Andreas Meinitzer Clinical Institute of Medical and Chemical Laboratory Diagnostics, Auenbruggerplatz 34, Medical University of Graz, A-8036 Graz, Austria; Phone: +43/316/385-83988; Fax: +43/316/385-13419, E-mail: andreas.meinitzer@medunigraz.at https://orcid.org/0000-0002-7883-7973
  • Dietmar Enko Clinical Institute of Medical and Chemical Laboratory Diagnostics, Medical University of Graz, Graz, Austria https://orcid.org/0000-0002-1173-0928
  • Peter Schober Department of Pediatric and Adolescent Surgery, Medical University of Graz, Graz, Austria https://orcid.org/0000-0001-7713-761X
  • Georg Singer Department of Pediatric and Adolescent Surgery, Medical University of Graz, Graz, Austria https://orcid.org/0000-0003-4770-3144
  • Christoph Castellani Department of Pediatric and Adolescent Surgery, Medical University of Graz, Graz, Austria https://orcid.org/0000-0002-4512-3640
  • Markus Herrmann Clinical Institute of Medical and Chemical Laboratory Diagnostics, Medical University of Graz, Graz, Austria https://orcid.org/0000-0002-3559-9899
  • Sandra J. Holasek Division of Immunology and Pathophysiology, Otto Loewi Research Center, Medical University of Graz, Graz, Austria https://orcid.org/0000-0002-2958-3516
  • Holger Till Department of Pediatric and Adolescent Surgery, Medical University of Graz, Graz, Austria https://orcid.org/0000-0002-1350-596X
  • Jana Maria Windhaber Department of Pediatric and Adolescent Surgery, Medical University of Graz, Graz, Austria https://orcid.org/0000-0002-8484-7721

DOI:

https://doi.org/10.17179/excli2022-4889

Keywords:

tryptophan, kynurenine, kynurenic acid, kynurenine pathway, exercise

Abstract

The maximal oxygen uptake (VO2max) and maximal power output (Pmax) are commonly used parameters to evaluate the endurance fitness status. A connection between exercise and the kynurenine pathway (KP), which describes the metabolism of unused tryptophan, has already been reported. However, a potential association of the KP with endurance fitness levels remains unknown. In this study, adolescent competitive athletes performed an exhaustive incremental exercise test. Blood samples were taken before, directly after, and 30 minutes after the end of exercise. Tryptophan (Trp), kynurenine (Kyn) and kynurenic acid (KA) serum levels were determined by high-performance liquid chromatography (HPLC). Forty-four male and 27 female athletes (median age: 16 years) were recruited. During exhaustive exercise tests, Trp initially declined and then increased 30 minutes after discontinuing exercise. Similar findings were observed for Kyn, whereas KA levels behaved inversely. After incremental exhaustive exercise the relative increase of Trp concentrations, termed the tryptophan-recovery-index (TRI), showed a highly significant positive correlation with VO2max and Pmax (r=0.468 and 0.491, p-values <0.001). There was a significant gender-difference with higher levels of all metabolites at all measured time points in male participants. In the present study, a highly significant correlation was found between the TRI and the maximal oxygen uptake in well-trained athletes. The implementation of TRI can therefore be suggested as a biomarker for physical fitness.

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Published

2022-06-24

How to Cite

Pichler, A., Meinitzer, A., Enko, D., Schober, P., Singer, G., Castellani, C., Herrmann, M., Holasek, S. J., Till, H., & Windhaber, J. M. (2022). Tryptophan recovery index as a new biomarker for fitness. EXCLI Journal, 21, 888–896. https://doi.org/10.17179/excli2022-4889

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