Browsing by Subject "TRYPTOPHAN"

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    TGF-β1, neopterin, tetrahydrobiopterin, and nitric oxide levels in pediatric obsessive-compulsive disorder
    (ELSEVIER) Özkan, Y; Kandemir, H; Sapmaz, SY; Taneli, F
    The biological mechanisms underlying obsessive-compulsive disorder (OCD) are not sufficiently elucidated. Chronic inflammation and oxidative stress were shown to increase neopterin and decrease tetrahydrobiopterin (BH4) levels by activating the neopterin-BH4 pathway. This study compared serum TGF-beta 1, TNF-alpha, IL-1 beta, IL-2, IL-6, IL-10, IL-17, neopterin, BH4, and nitric oxide (NO) levels between child and adolescent patients diagnosed with OCD and a healthy control group. The study included 29 patients diagnosed with OCD (comorbidity free, drug free) and 28 healthy children as an aged and sex matched control group. Serum samples were analyzed for TGF-beta 1, TNF-alpha, IL-1 beta, IL-2, IL-6, IL-10, IL-17, neopterin, and BH4 by using enzyme-linked immunosorbent assay method, and NO concentrations were assessed by colorimetric method based on Griess reaction. All cytokine levels were found to be low, but this decrease was statistically significant only for TGF-beta 1. The neopterin and NO levels were significantly higher and BH4 significantly lower in children with OCD compared to the healthy control group. Also, a statistically significant correlation was found between NO, neopterin, and BH4 levels. The results of our study show that the levels of TGF-beta 1 and NO and the activation of the neopterin-BH4 pathway may be implicated in the pathophysiology of OCD.
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    The role of the kynurenine pathway and quinolinic acid in adolescent major depressive disorder
    (WILEY) Öztürk, M; Sapmaz, SY; Kandemir, H; Taneli, F; Aydemir, Ö
    Background The biological mechanisms underlying major depressive disorder (MDD) are not yet sufficiently understood. The kynurenine pathway has been proposed to play a key role between peripheral inflammation and alterations in the central nervous system. This is because of reduced usability of tryptophan (TRP) and production of oxygen radicals and highly potent neurotoxic agents in this pathway. Objective In this study, we aimed to compare the metabolites of the serum kynurenine pathway (tryptophan, kynurenine, quinolinic acid and kynurenic acid) and IFN-gamma, IL-6, IL-1 beta and high-sensitivity C-reactive protein (hsCRP) levels in patients with major depressive disorder and in healthy controls and to evaluate the relationship between cytokine levels and the functioning of the kynurenine pathway. Methods Clinical and biochemical data from the patients were obtained and assessed in a cross-sectional design. Serum samples were analysed for IL-6, IL-1 beta, interferon (IFN)-gamma, tryptophan (TRP), quinolinic acid (QUIN), kynurenic acid (KYNA) and kynurenine (Kyn) levels by the enzyme-linked immunosorbent assay. hsCRP test was analysed by the immunoturbidimetric method. Results In total, 48 adolescent patients with major depressive disorder (no drug use) and 31 healthy controls were included in the study. TRP levels were observed to be significantly lower in patients with MDD than in healthy controls (P = .046); the Kyn/TRP ratio was significantly higher in patients with MDD than in healthy controls (P = .032); the levels of QUIN were significantly higher in patients with MDD than in healthy controls (P = .003). No significant difference was found between the groups in terms of other kynurenine metabolites and cytokines levels. Conclusion These results suggest that the Kyn and related molecular pathways may play a role in the pathophysiology of MDD. The most important finding was the increased level of QUIN, which has a neurotoxic effect, in the kynurenine pathway.