{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,24]],"date-time":"2026-07-24T09:58:43Z","timestamp":1784887123063,"version":"3.55.0"},"reference-count":69,"publisher":"MDPI AG","issue":"24","license":[{"start":{"date-parts":[[2023,12,11]],"date-time":"2023-12-11T00:00:00Z","timestamp":1702252800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Cells"],"abstract":"<jats:p>Tryptophan (TRP) catabolites exert neuroactive effects, with the plethora of evidence suggesting that kynurenic acid (KYNA), a catabolite of the kynurenine pathway (KP), acts as the regulator of glutamate and acetylcholine in the brain, contributing to the schizophrenia pathophysiology. Newer evidence regarding measures of KP metabolites in the blood of schizophrenia patients and from the central nervous system suggest that blood levels of these metabolites by no means could reflect pathological changes of TRP degradation in the brain. The aim of this study was to investigate plasma concentrations of TRP, kynurenine (KYN) and KYNA at the acute phase and remission of schizophrenia in a prospective, case-control study of highly selected and matched schizophrenia patients and healthy individuals. Our study revealed significantly decreased KYN and KYNA in schizophrenia patients (p &lt; 0.001), irrespective of illness state, type of antipsychotic treatment, number of episodes or illness duration and no differences in the KYN\/TRP ratio between schizophrenia patients and healthy individuals. These findings could be interpreted as indices that kynurenine pathway might not be dysregulated in the periphery and that other factors contribute to observed disturbances in concentrations, but as our study had certain limitations, we cannot draw definite conclusions. Further studies, especially those exploring other body compartments that participate in kynurenine pathway, are needed.<\/jats:p>","DOI":"10.3390\/cells12242814","type":"journal-article","created":{"date-parts":[[2023,12,11]],"date-time":"2023-12-11T06:56:00Z","timestamp":1702277760000},"page":"2814","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":13,"title":["Decreased Plasma Levels of Kynurenine and Kynurenic Acid in Previously Treated and First-Episode Antipsychotic-Naive Schizophrenia Patients"],"prefix":"10.3390","volume":"12","author":[{"given":"Milo\u0161","family":"Markovi\u0107","sequence":"first","affiliation":[{"name":"Clinic for Mental Disorders \u201cDr Laza Lazarevi\u0107\u201d, 11000 Belgrade, Serbia"},{"name":"Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4338-1953","authenticated-orcid":false,"given":"Nata\u0161a","family":"Petronijevi\u0107","sequence":"additional","affiliation":[{"name":"Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia"},{"name":"Institute of Medical and Clinical Biochemistry, Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Milena","family":"Sta\u0161evi\u0107","sequence":"additional","affiliation":[{"name":"Clinic for Mental Disorders \u201cDr Laza Lazarevi\u0107\u201d, 11000 Belgrade, Serbia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ivana","family":"Sta\u0161evi\u0107 Karli\u010di\u0107","sequence":"additional","affiliation":[{"name":"Clinic for Mental Disorders \u201cDr Laza Lazarevi\u0107\u201d, 11000 Belgrade, Serbia"},{"name":"Faculty of Medicine, University of Pri\u0161tina\u2014Kosovska Mitrovica, 38220 Kosovska Mitrovica, Serbia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Milica","family":"Velimirovi\u0107","sequence":"additional","affiliation":[{"name":"Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia"},{"name":"Institute of Medical and Clinical Biochemistry, Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tihomir","family":"Stojkovi\u0107","sequence":"additional","affiliation":[{"name":"Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia"},{"name":"Institute of Medical and Clinical Biochemistry, Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6983-4412","authenticated-orcid":false,"given":"Slavica","family":"Risti\u0107","sequence":"additional","affiliation":[{"name":"Institute of Medical and Clinical Biochemistry, Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0000-3216-9853","authenticated-orcid":false,"given":"Mina","family":"Stojkovi\u0107","sequence":"additional","affiliation":[{"name":"Clinic for Neurology, University Clinical Centre of Ni\u0161, 18000 Ni\u0161, Serbia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nata\u0161a","family":"Mili\u0107","sequence":"additional","affiliation":[{"name":"Institute for Medical Statistics and Informatics, Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia"},{"name":"Department for Internal Medicine, Mayo Clinic, Rochester, MN 55905, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2185-7551","authenticated-orcid":false,"given":"Tatjana","family":"Nikoli\u0107","sequence":"additional","affiliation":[{"name":"Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia"},{"name":"Institute of Medical and Clinical Biochemistry, Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2023,12,11]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"273","DOI":"10.1016\/0304-3940(84)90050-8","article-title":"Kynurenic acid blocks neurotoxicity and seizures induced in rats by the related brain metabolite quinolinic acid","volume":"48","author":"Foster","year":"1984","journal-title":"Neurosci. 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