Interleukin-6 is associated with tryptophan metabolism and signs of depression in individuals with carbohydrate malabsorption

Authors

  • Dietmar Enko Clinical Institute of Medical and Chemical Laboratory Diagnostics, Medical University of Graz, Auenbruggerplatz 15, 8036 Graz, Austria; Tel: +43 316 385-13145; Fax: +43 316 385-13430; E-mail: enko.dietmar@gmx.at
  • Sieglinde Zelzer Clinical Institute of Medical and Chemical Laboratory Diagnostics, Medical University of Graz, Graz, Austria
  • Julian Wenninger Clinical Institute of Medical and Chemical Laboratory Diagnostics, Medical University of Graz, Graz, Austria
  • Sandra Holasek Department of Immunology and Pathophysiology, Medical University of Graz, Graz, Austria
  • Wolfgang J. Schnedl Practice for General Internal Medicine, Bruck/Mur, Austria
  • Andreas Baranyi Department of Psychiatry and Psychotherapeutic Medicine, Medical University of Graz, Graz, Austria
  • Markus Herrmann Clinical Institute of Medical and Chemical Laboratory Diagnostics, Medical University of Graz, Graz, Austria
  • Andreas Meinitzer Clinical Institute of Medical and Chemical Laboratory Diagnostics, Medical University of Graz, Graz, Austria

DOI:

https://doi.org/10.17179/excli2020-2940

Keywords:

depression, inflammation, interleukin-6, interferon-gamma, tumor necrosis factor-alpha, lactoferrin

Abstract

The aim of the present study was to investigate possible associations between interleukin-6 (IL-6), interferon-gamma (INF-γ), tumor necrosis factor-alpha (TNF-α), lactoferrin and lipopolysaccharide binding protein (LBP) with TRP metabolism and signs of depression in a large cohort of outpatients referred for carbohydrate malabsorption testing. Serum concentrations of IL-6, INF-γ, TNF-α, lactoferrin, LBP, tryptophan (TRP), kynurenine (KYN) and kynuric acid were determined in 250 adults referred for lactose and fructose malabsorption testing. All participants filled out the Beck Depression Inventory (BDI). Serum IL-6 levels were positively correlated with the BDI score (p = 0.001, ρ = 0.205) and indicators of TRP metabolism (KYN/TRP ratio, KYN) (P-values < 0.05, ρ = 0.176 and 0.136). Ninety-five individuals with a BDI score > 13 showed significantly higher IL-6 serum levels (1.7 [1.0 – 2.8] vs. 1.1 [0.8 – 1.7] pg/mL, p < 0.001) compared to 115 individuals with a BDI score ≤ 13. LBP showed a positive correlation with the KYN/TRP ratio (p = 0.005, ρ = 0.177). IL-6 and LBP were associated with indicators of TRP metabolism. IL-6 was found to be linked to signs of depression. Individuals with the presence of depressive symptoms showed higher serum IL-6 levels compared to individuals without depressive symptoms.

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Published

2020-10-28

How to Cite

Enko, D., Zelzer, S., Wenninger, J., Holasek, S., Schnedl, W. J., Baranyi, A., … Meinitzer, A. (2020). Interleukin-6 is associated with tryptophan metabolism and signs of depression in individuals with carbohydrate malabsorption. EXCLI Journal, 19, 1414–1422. https://doi.org/10.17179/excli2020-2940

Issue

Vol. 19 (2020)

Section

Original articles

License

Copyright (c) 2020 Dietmar Enko, Sieglinde Zelzer, Julian Wenninger, Sandra Holasek, Wolfgang J. Schnedl, Andreas Baranyi, Markus Herrmann, Andreas Meinitzer

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