Investigating the kynurenine pathway in pediatric metabolic health

Fatma Özgüç Çömlek; Dilek Bingöl Aydın; Fikret Akyürek; Muslu Kazım Körez; Fuat Buğrul

doi:10.1515/jpem-2025-0477

Article

Investigating the kynurenine pathway in pediatric metabolic health

Fatma Özgüç Çömlek , Dilek Bingöl Aydın , Fikret Akyürek , Muslu Kazım Körez and Fuat Buğrul

Published/Copyright: October 30, 2025

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From the journal Journal of Pediatric Endocrinology and Metabolism Volume 38 Issue 12

Abstract

Objectives

The rise in obesity has led to a higher incidence of metabolic diseases in children. Overnutrition leads to increased intake and availability of tryptophan (TRP). Research indicates a link between indoleamine 2,3-dioxygenase (IDO) activity, the activation of the tryptophan catabolic pathway, and inflammation associated with obesity. This study investigated how pediatric obesity affects tryptophan metabolism and its potential link to metabolic syndrome.

Methods

This prospective cohort study included 86 children aged 10 years and older, 56 of whom were obese. Obese children with body mass index (BMI) >95th percentile were divided into two groups: obese (BMI greater than 120 % of the 95th percentile for age and sex) and severely obese (BMI greater than 140 % of the 95th percentile for age and sex). Serum levels of kynurenine pathway metabolites were determined by liquid chromatography-mass spectrometry/mass spectrometry system.

Results

The mean ages (13.6 and 13.2 years) and gender distribution (36.7 and 46.2 % male) were similar across the groups. There were significant differences in tryptophan levels between the groups, being higher in the obese groups (p<0.001). 3-hydroxykynurenine (3HK) was significantly higher in the obese group (p=0.029). 3-hydroxykynurenine/kynurenine (3HK/KYN) ratio also significantly correlated with increased GGT and triglyceride levels and low HDL. Also higher 3HK/KYN ratio was correlated with elevated systolic blood pressure (SBP) and diastolic blood pressure (DBP) levels. No significant relationship was found between the KYN/TRP ratio and obesity metabolic syndrome indicators.

Conclusions

Although plasma kynurenine pathway metabolites showed some changes in children with obesity, larger series studies are needed to determine the relationship with metabolic syndrome.

Keywords: obesity; children; kynurenine pathway; inflammation; metabolic syndrome

Corresponding author: Dr. Fatma Özgüç Çömlek, Selçuk Üniversity Medical Faculty, Pediatric Endocrinology, Konya, Türkiye, E-mail: fatmaozguc@gmail.com

Research ethics: Approval for the study was obtained from the Selçuk University Faculty of Medicine ethics committee with the decision number 2025/287.
Informed consent: Informed consent was obtained from the patients and their parents who participated in the study.
Author contributions: Concept- Fatma Özgüç Çömlek, Design- Fatma Özgüç Çömlek Supervision- Fatma Özgüç Çömlek, Dilek Bingöl Aydın Materials, Fatma Özgüç Çömlek, data Collection and /or Processing- Fatma Özgüç Çömlek, Fuat Buğrul, Fikret Akyürek Analysis and /or interpretation- Fatma Özgüç Çömlek,Fikret Akyürek, Muslu Kazım Körez Literature Review Fatma Özgüç Çömlek, Dilek Bingöl Aydın, Fuat Buğrul Writer- Fatma Özgüç Çömlek, Muslu Kazım Körez;Critical Review- Fatma Özgüç Çömlek, Muslu Kazım Körez.
Use of Large Language Models, AI and Machine Learning Tools: None declared.
Conflict of interest: The authors state no conflict of interest.
Research funding: None declared.
Data availability: Data can be shared upon request.

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Received: 2025-08-20

Accepted: 2025-10-11

Published Online: 2025-10-30

Published in Print: 2025-12-17

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Articles in the same Issue

https://doi.org/10.1515/jpem-2025-0477

Keywords for this article

obesity; children; kynurenine pathway; inflammation; metabolic syndrome