Enko, DietmarZelzer, SieglindeWenninger, JulianHolasek, SandraSchnedl, Wolfgang J.Baranyi, AndreasHerrmann, MarkusMeinitzer, Andreas2020-12-152020-12-152020-10-28Enko, D., Zelzer, S., Wenninger, J., Holasek, S., Schnedl, W. J., Baranyi, A., Herrmann, M., & 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/excli2020-29401611-2156http://hdl.handle.net/2003/3989910.17877/DE290R-21789The 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.enIfADo - Leibniz Research Centre for Working Environment and Human Factors, DortmundEXCLI Journal;Vol. 19 2020https://creativecommons.org/licenses/by/4.0/DepressionInflammationInterleukin-6Interferon-gammaTumor necrosis factor-alphaLactoferrin610article (journal)