Cited by 59Tryptophan and brain disordersStress Responses and CortisolTreatment of Major Depression

Kynurenine metabolism and inflammation-induced depressed mood: a human experimental study

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Kruse, Jennifer L., Cho, Joshua Hyong-Jin, Olmstead, Richard, Hwang, Lin, Faull, Kym, Eisenberger, Naomi I., Irwin, Michael R.·2019·Psychoneuroendocrinology

Abstract

Inflammation has an important physiological influence on mood and behavior. Kynurenine metabolism is hypothesized to be a pathway linking inflammation and depressed mood, in part through the impact of kynurenine metabolites on glutamate neurotransmission in the central nervous system. This study evaluated whether the circulating concentrations of kynurenine and related compounds change acutely in response to an inflammatory challenge (endotoxin administration) in a human model of inflammation-induced depressed mood, and whether such metabolite changes relate to mood change. Adults (n = 115) were randomized to receive endotoxin or placebo. Mood (Profile of Mood States), plasma cytokine (interleukin-6, tumor necrosis factor-α) and metabolite (kynurenine, tryptophan, kynurenic acid, quinolinic acid) concentrations were repeatedly measured before the intervention, and at 2 and 6 h post-intervention. Linear mixed models were used to evaluate relationships between mood, kynurenine and related compounds, and cytokines. Kynurenine, kynurenic acid, and tryptophan (but not quinolinic acid) concentrations changed acutely (p's all <0.001) in response to endotoxin as compared to placebo. Neither kynurenine, kynurenic acid nor tryptophan concentrations were correlated at baseline with cytokine concentrations, but all three were significantly correlated with cytokine concentrations over time in response to endotoxin. Quinolinic acid concentrations were not correlated with cytokine concentrations either before or following endotoxin treatment. In those who received endotoxin, kynurenine (p = 0.049) and quinolinic acid (p = 0.03) positively correlated with depressed mood, although these findings would not survive correction for multiple testing. Changes in tryptophan and kynurenine pathway metabolites did not mediate the relationship between cytokines and depressed mood. Further work is necessary to clarify the pathways leading from inflammation to depressed mood in humans.

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Crossref · 10.1016/j.psyneuen.2019.104371

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  • Dysregulation of the kynurenine pathway has been linked to several brain disorders, including depression, schizophrenia, and autism spectrum disorder.

    “Dysregulation of the kynurenine pathway has been linked to several brain disorders, including depression (395), schizophrenia (396, 397), and ASD (398).”
  • The kynurenine pathway has been implicated in general depressed mood (inflammation-induced depression) and postpartum depression.

    “The kynurenine pathway has been implicated not only in general depressed mood (inflammation-induced depression) [184,214,219] but also postpartum depression [120].”

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  1. Eisenberger NI, Berkman ET, Inagaki TK, Rameson LT, Mashal NM, Irwin MR, 2010b Inflammation-induced anhedonia: endotoxin reduces ventral striatum responses to reward. Biol Psychiatry 68, 748– 754. 20719303 PMC3025604

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Authors
Kruse, J. L., Cho, J. H.-J., Olmstead, R., Hwang, L., Faull, K., Eisenberger, N. I., & Irwin, M. R.
Affiliations
University of California, Los Angeles (US)
Venue
Psychoneuroendocrinology
Publisher
Elsevier BV
Published
2019-11
Volume
109
Pages
104371
ISSN
0306-4530 (ISSN-L)
OpenAlex
W2954367215
Cited by
59
References
54
Citations by year
2026: 10 · 2025: 7 · 2024: 9 · 2023: 7 · 2022: 12 · 2021: 9 · 2020: 5
FWCI
2.13
Type
journal article
Language
en
Open access
Locations
  • Psychoneuroendocrinology (publishedVersion)
  • PubMed (publishedVersion)
  • PubMed Central (acceptedVersion)
  • eScholarship (California Digital Library) (submittedVersion)
Funders
  • National Institute on Aging
  • National Institute of Mental Health
  • National Center for Advancing Translational Sciences
Topics
  • Life Sciences › Neuroscience › Biological Psychiatry › Tryptophan and brain disorders
  • Life Sciences › Neuroscience › Behavioral Neuroscience › Stress Responses and Cortisol
  • Health Sciences › Medicine › Pharmacology › Treatment of Major Depression
Keywords
kynurenine metabolism, inflammation, depressive mood, endotoxin, lipopolysaccharide, kynurenic acid, quinolinic acid, tryptophan, cytokines, interleukin-6, TNF-α, glutamatergic neurotransmission
MeSH terms
Adult, Affect, Depression, Endotoxins, Female, Humans, Inflammation, Kynurenic Acid, Kynurenine, Male, Middle Aged, Sex Factors, Tryptophan, Tumor Necrosis Factor-alpha, Interleukin-6, Cytokines, Quinolinic Acid

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