{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,15]],"date-time":"2026-10-15T00:49:24Z","timestamp":1792025364203,"version":"4.4.0"},"reference-count":23,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2025,2,5]],"date-time":"2025-02-05T00:00:00Z","timestamp":1738713600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Gazi University Scientific Research Projects Coordination Unit","award":["6255"],"award-info":[{"award-number":["6255"]}]},{"name":"Gazi University Scientific Research Projects Coordination Unit","award":["01\/2019\u201335"],"award-info":[{"award-number":["01\/2019\u201335"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["JCM"],"abstract":"<jats:p>Background and Aim: Inflammatory bowel disease (IBD), which comprises ulcerative colitis (UC) and Crohn\u2019s disease (CD), is characterized by chronic inflammation and fluctuating disease activity. This study aimed to evaluate serum tryptophan (TRP) and its metabolites as potential biomarkers for predicting disease activation in comparison to fecal calprotectin (FC). Methods: This prospective study included 115 patients (77 with UC and 38 with CD). Disease activity was assessed based on clinical and endoscopic findings. Serum TRP levels and their metabolites were measured using liquid chromatography\u2013tandem mass spectrometry (LC-MS\/MS), whereas FC levels were analyzed using an enzyme-linked immunosorbent assay (ELISA). Results: Serum TRP levels \u2264 11,328.41 ng\/mL predicted disease activation with 72.1% sensitivity and 62.7% specificity, whereas FC levels \u2265 89.60 \u00b5g\/g showed 84.2% sensitivity and 67.6% specificity. The TRP-to-C-reactive protein (CRP) ratio (TRP\/CRP) demonstrated superior diagnostic accuracy, with an area under the curve (AUC) of 0.847. Conclusions: The TRP\/CRP ratio is a novel and comprehensive approach for predicting disease activation in IBD patients. Although FC remains the gold standard, TRP and its metabolites provide valuable complementary insights. Further research is required to validate these findings in larger cohorts.<\/jats:p>","DOI":"10.3390\/jcm14031016","type":"journal-article","created":{"date-parts":[[2025,2,5]],"date-time":"2025-02-05T10:09:52Z","timestamp":1738750192000},"page":"1016","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":3,"title":["Evaluation of Tryptophan and Its Metabolites in Predicting Disease Activation in Inflammatory Bowel Disease"],"prefix":"10.3390","volume":"14","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-2464-1975","authenticated-orcid":false,"given":"Ali","family":"Karata\u015f","sequence":"first","affiliation":[{"name":"Department of Gastroenterology, Faculty of Medicine, Gazi University, Ankara 06560, Turkey"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tarkan","family":"Karakan","sequence":"additional","affiliation":[{"name":"Department of Gastroenterology, Faculty of Medicine, Gazi University, Ankara 06560, Turkey"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nergiz","family":"Ekmen","sequence":"additional","affiliation":[{"name":"Department of Gastroenterology, Faculty of Medicine, Gazi University, Ankara 06560, Turkey"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2413-7733","authenticated-orcid":false,"given":"Yasemin","family":"\u00dcnsal","sequence":"additional","affiliation":[{"name":"Department of Internal Medicine, Faculty of Medicine, Gazi University, Ankara 06560, Turkey"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4494-6378","authenticated-orcid":false,"given":"G\u00fcls\u00fcm Feyza","family":"T\u00fcrke\u015f","sequence":"additional","affiliation":[{"name":"Department of Medical Biochemistry, Graduate School Of Health Sciences, Gazi University, Ankara 06560, Turkey"},{"name":"Department of Clinical Biochemistry, Faculty of Medicine, Ankara University, Ankara 06230, Turkey"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"\u00d6zlem","family":"G\u00fclbahar","sequence":"additional","affiliation":[{"name":"Department of Clinical Biochemistry, Faculty of Medicine, Gazi University, Ankara 06560, Turkey"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mehmet","family":"Cindoruk","sequence":"additional","affiliation":[{"name":"Department of Gastroenterology, Faculty of Medicine, Gazi University, Ankara 06560, Turkey"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9593-3705","authenticated-orcid":false,"given":"Mustafa","family":"Ergin","sequence":"additional","affiliation":[{"name":"Department of Gastroenterology, Faculty of Medicine, Gazi University, Ankara 06560, Turkey"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6799-3391","authenticated-orcid":false,"given":"G\u00fcner","family":"K\u0131l\u0131\u00e7","sequence":"additional","affiliation":[{"name":"Department of Gastroenterology, Faculty of Medicine, Gazi University, Ankara 06560, Turkey"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mehmet","family":"\u0130bi\u015f","sequence":"additional","affiliation":[{"name":"Department of Gastroenterology, Faculty of Medicine, Gazi University, Ankara 06560, Turkey"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mehmet","family":"Arhan","sequence":"additional","affiliation":[{"name":"Department of Gastroenterology, Faculty of Medicine, Gazi University, Ankara 06560, Turkey"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"\u0130brahim","family":"Do\u011fan","sequence":"additional","affiliation":[{"name":"Department of Gastroenterology, Faculty of Medicine, Gazi University, Ankara 06560, Turkey"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hasan","family":"Da\u011fl\u0131","sequence":"additional","affiliation":[{"name":"Department of Clinical Biochemistry, Faculty of Medicine, Gazi University, Ankara 06560, Turkey"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,2,5]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1214","DOI":"10.1002\/ibd.21849","article-title":"Serum analysis of tryptophan catabolism pathway: Correlation with Crohn\u2019s disease activity","volume":"18","author":"Gupta","year":"2012","journal-title":"Inflamm. 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