Evidence map›Paper›PMID 42338096›Full record

ArticleJournal of neurochemistry2026

Kynurenine Pathway Metabolite Levels in Drug Naïve and Risperidone Treated Schizophrenia: Insights From Systemic and Post-Mortem Brain Tissue Analysis.

Joyappa Nikhil, Chinnasamy Thirumoorthy, Priyamvada Sharma, Vijay Kumar, Shivarama Varambally, Kuppan Gokulakrishnan

Abstract read
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Article in Journal of neurochemistry, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

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1 · What the graph read from it

What it found

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2 · The registry

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3 · Its place in the literature

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4 · The record

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5 · Who and what money

Authors and funding

6 authors.

Joyappa NikhilDepartment of Neurochemistry, National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru, India.ORCID https://orcid.org/0000-0001-7345-284X
Chinnasamy ThirumoorthyDepartment of Neurochemistry, National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru, India.ORCID https://orcid.org/0000-0003-1688-1933
Priyamvada SharmaDepartment of Clinical Psychopharmacology and Neurotoxicology, National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru, India.ORCID https://orcid.org/0000-0001-6024-0055
Vijay KumarDepartment of Psychiatry, National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru, India.ORCID https://orcid.org/0000-0003-4949-4083
Shivarama VaramballyDepartment of Psychiatry, National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru, India.ORCID https://orcid.org/0000-0003-1420-8606
Kuppan GokulakrishnanDepartment of Neurochemistry, National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru, India.ORCID https://orcid.org/0000-0003-3167-8239

Funding

National Institute of Mental Health and Neuro Sciences (NIMHANS) Intramural Research Grant NIMH/PROJ/KG/00588/2019-20
6 · The paper itself

Abstract

Kynurenine pathway (KP), the principal route of tryptophan (TRY) metabolism, is implicated in schizophrenia (SCZ), but findings remain inconsistent, particularly regarding peripheral-central associations and links to immune dysregulation. We measured KP metabolites, cytokines, and metabolic risk factors in serum from drug-naïve (DN) and risperidone-treated (RT) SCZ patients versus healthy controls (HC) as well as in post-mortem brain tissue from an independent cohort by assessing KP metabolites, enzyme expression (mRNA, protein) and cytokine profiles. We recruited a total of 227 participants from the clinical services of a large neuropsychiatric hospital, which included DN SCZ (n = 66), RT SCZ (n = 87), and HC (n = 74). Additionally, brain KP metabolite levels and the mRNA and protein expression of key enzymes and cytokines were evaluated in the dorsolateral prefrontal cortex (DLPFC) samples from the post-mortem cohort of 10 SCZ patients and 17 controls. KP metabolites were measured using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Both DN and RT groups exhibited significantly reduced TRY (p < 0.05), elevated kynurenine (KYN), kynurenic acid (KYNA), KYN/TRY ratio and serotonin (SER) in serum (p < 0.001), alongside higher TNF-α, and IFN-γ and lower IL-10 (p < 0.001 for both). These alterations were correlated with metabolic risk factors, symptom severity of SCZ, and immune markers, and these remained associated with disease status after adjusting for confounders. Post-mortem analyses confirmed increased brain KYN (p < 0.05) and KYNA (p < 0.001) in the DLPFC of SCZ, accompanied by upregulation of Tryptophan 2,3-dioxygenase (TDO2) (p < 0.001) and Kynurenine aminotransferase II (KAT II) (p < 0.05) expression and elevated pro-inflammatory cytokines. Our findings provide convergent evidence for KP dysregulation in SCZ, linking immune activation with enhanced change toward KYNA synthesis both systemically and centrally. The observed alterations across independent serum and post-mortem brain cohorts support the potential relevance of these molecular signatures to SCZ pathophysiology and their possible therapeutic implications.

Indexed as

Antipsychotic AgentsBrainKynurenineRisperidoneSchizophreniaAdultAutopsyCohort StudiesCytokinesFemaleHumansMaleMiddle AgedAntipsychotic AgentsCytokinesKynurenineRisperidone

Identifiers

PMID42338096
PMCPMC13542786

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.