scholarly journals Tryptophan Metabolism in Rat Liver after Administration of Tryptophan, Kynurenine Metabolites, and Kynureninase Inhibitors

2016 ◽  
Vol 9 ◽  
pp. IJTR.S38190 ◽  
Author(s):  
Abdulla A.-B. Badawy ◽  
Samina Bano
Keyword(s):  
Rat Liver ◽  
Immune Activation ◽  
Kynurenic Acid ◽  
Chronic Administration ◽  
Kynurenine Pathway ◽  
Tryptophan Metabolism ◽  
Disease States ◽  
Metabolite Concentrations ◽  
Hydroxyanthranilic Acid ◽  
Stimulation Of

Rat liver tryptophan (Trp), kynurenine pathway metabolites, and enzymes deduced from product/substrate ratios were assessed following acute and/or chronic administration of kynurenic acid (KA), 3-hydroxykynurenine (3-HK), 3-hydroxyanthranilic acid (3-HAA), Trp, and the kynureninase inhibitors benserazide (BSZ) and carbidopa (CBD). KA activated Trp 2,3-dioxygenase (TDO), possibly by increasing liver 3-HAA, but inhibited kynurenine aminotransferase (KAT) and kynureninase activities with 3-HK as substrate. 3-HK inhibited kynureninase activity from 3-HK. 3-HAA stimulated TDO, but inhibited kynureninase activity from K and 3-HK. Trp (50 mg/kg) increased kynurenine metabolite concentrations and KAT from K, and exerted a temporary stimulation of TDO. The kynureninase inhibitors BSZ and CBD also inhibited KAT, but stimulated TDO. BSZ abolished or strongly inhibited the Trp-induced increases in liver Trp and kynurenine metabolites. The potential effects of these changes in conditions of immune activation, schizophrenia, and other disease states are discussed.

scholarly journals Effects of Tranilast on the Urinary Excretion of Kynurenic and Quinolinic Acid under Conditions of L Tryptophan Loading

2013 ◽  
Vol 6 ◽  
pp. IJTR.S12797 ◽  
Author(s):  
Rowland R. Noakes
Keyword(s):  
Urinary Excretion ◽  
Quinolinic Acid ◽  
Kynurenic Acid ◽  
Competitive Inhibitor ◽  
Kynurenine Pathway ◽  
Tryptophan Metabolism ◽  
Autoimmune Response ◽  
Current Therapy ◽  
Indoleamine 2 ◽  
Hydroxyanthranilic Acid

The pathogenesis of morphea and other cutaneous sclerosing disorders remain poorly understood. Although they are considered to be autoimmune disorders, abnormal tryptophan metabolism may be involved. Current therapy is directed to supressing the autoimmune response. Demonstration of a therapeutic response to manipulation of the kynurenine pathway would both support a role for abnormal tryptophan metabolism and offer additional targets for therapy. Tranilast is a 3-hydroxyanthranilic acid derivative known to target the kynurenine pathway. The aim of this study was to see if tranilast lowered the urinary excretion of the kynurenine metabolites kynurenic and quinolinic acid under condition of L tryptophan loading in a volunteer. Mean baseline value for kynurenic acid and quinolinic acid were 1.1 and 2.1 mmol/mol creatinine, respectively. This rose to 5.6 and 3.8 mmol/mol creatinine respectively under conditions of L tryptophan loading 2 grams daily. Adding 1 g of tranilast daily lowered the values to 2.0 and 2.9 mmol/mol creatinine, respectively. These data suggest that tranilast acts as a competitive inhibitor of either indoleamine 2, 3-dioxygenase (IDO), tryptophan 2, 3 di-oxygenase (TDO) or both. As it involved only 1 subject, the results may not be representative of the larger population and must be considered preliminary.

scholarly journals Organ Correlation with Tryptophan Metabolism Obtained by Analyses of TDO-KO and QPRT-KO Mice

2016 ◽  
Vol 9 ◽  
pp. IJTR.S37984 ◽  
Author(s):  
Katsumi Shibata ◽  
Tsutomu Fukuwatari
Keyword(s):  
Quinolinic Acid ◽  
Kynurenic Acid ◽  
Conversion Ratio ◽  
Tryptophan Metabolism ◽  
Limiting Factors ◽  
Xanthurenic Acid ◽  
Wild Type ◽  
Organ Specific ◽  
Hydroxyanthranilic Acid ◽  
Rate Limiting

The aim of this article is to report the organ-specific correlation with tryptophan (Trp) metabolism obtained by analyses of tryptophan 2,3-dioxygenase knockout (TDO-KO) and quinolinic acid phosphoribosyltransferase knockout (QPRT-KO) mice models. We found that TDO-KO mice could biosynthesize the necessary amount of nicotinamide (Nam) from Trp, resulting in the production of key intermediate, 3-hydroxyanthranilic acid. Upstream metabolites, such as kynurenic acid and xanthurenic acid, in the urine were originated from nonhepatic tissues, and not from the liver. In QPRT-KO mice, the Trp to quinolinic acid conversion ratio was 6%; this value was higher than expected. Furthermore, we found that QPRT activity in hetero mice was half of that in wild-type (WT) mice. Urine quinolinic acid levels remain unchanged in both hetero and WT mice, and the conversion ratio of Trp to Nam was also unaffected. Collectively, these findings show that QPRT was not the rate-limiting enzyme in the conversion. In conclusion, the limiting factors in the conversion of Trp to Nam are the substrate amounts of 3-hydroxyanthranilic acid and activity of 3-hydroxyanthranilic acid 3,4-dioxygenase in the liver.

ROLE OF KYNURENINE PATHWAY METABOLITES IN DEPRESSION-A REVIEW

2020 ◽  
pp. 1-6
Author(s):  
Priyadarshini Soni ◽  
Lubhan Singh ◽  
Prabhat Singh ◽  
Sokindra Kumar
Keyword(s):  
Amino Acid ◽  
Kynurenic Acid ◽  
Kynurenine Pathway ◽  
World Health ◽  
The World ◽  
Important Pathway ◽  
Hydroxyanthranilic Acid ◽  
Health Organization

Today most common psychiatric problem across the world is depression and stress is main source of ailment. According to World health organization, it will be the main cause of morbidity by 2020 in the world. Depression can critically affects the quality of life  as it is characterized by many symptoms like unhappy feeling, lack of interest and pleasure, down energy, inadequacy, regret feeling, slow-down of thoughts or reduction in physical movement, speech can affects, altered appetite or sleep, sad,  and increase the risk of suicide. Human body is inadequate to produce tryptophan which is a crucial amino acid; therefore it must be required from diet. After absorption, L-tryptophan crosses the BBB (Blood brain barrier) by non-specific L-type amino acid transporter and act as precursor to various metabolic pathways in central nervous system (CNS). Kynurenine is an important pathway that is associated with tryptophan (TRP) metabolism, where it develops a lot of metabolites such as 3-hydroxykynurenine (3HK), anthranilic acid (AA), kynurenic acid (KYNA), 3-hydroxyanthranilic acid (3HAA) and quinolinic acid (QUIN) known as kynurenines. It is already reported previously that disturbance in neuroprotective and neurotoxic metabolites leads to many psychiatric disorders. This review summarizes the role of kynurenine pathway metabolites in depression.   

scholarly journals Effects of Sleep Deprivation on the Tryptophan Metabolism

2020 ◽  
Vol 13 ◽  
pp. 117864692097090
Author(s):  
Abid Bhat ◽  
Ananda Staats Pires ◽  
Vanessa Tan ◽  
Saravana Babu Chidambaram ◽  
Gilles J Guillemin
Keyword(s):  
Sleep Deprivation ◽  
Kynurenic Acid ◽  
Second Messengers ◽  
Sleep Time ◽  
Kynurenine Pathway ◽  
Tryptophan Metabolism ◽  
Cellular Functions ◽  
Intracellular Second Messengers ◽  
The Impact ◽  
The Brain

Sleep has a regulatory role in maintaining metabolic homeostasis and cellular functions. Inadequate sleep time and sleep disorders have become more prevalent in the modern lifestyle. Fragmentation of sleep pattern alters critical intracellular second messengers and neurotransmitters which have key functions in brain development and behavioral functions. Tryptophan metabolism has also been found to get altered in SD and it is linked to various neurodegenerative diseases. The kynurenine pathway is a major regulator of the immune response. Adequate sleep alleviates neuroinflammation and facilitates the cellular clearance of metabolic toxins produced within the brain, while sleep deprivation activates the enzymatic degradation of tryptophan via the kynurenine pathway, which results in an increased accumulation of neurotoxic metabolites. SD causes increased production and accumulation of kynurenic acid in various regions of the brain. Higher levels of kynurenic acid have been found to trigger apoptosis, leads to cognitive decline, and inhibit neurogenesis. This review aims to link the impact of sleep deprivation on tryptophan metabolism and associated complication in the brain.

scholarly journals Vitamins B2and B6as determinants of kynurenines and related markers of interferon-γ-mediated immune activation in the community-based Hordaland Health Study

2014 ◽  
Vol 112 (7) ◽  
pp. 1065-1072 ◽  
Author(s):  
Despoina Theofylaktopoulou ◽  
Arve Ulvik ◽  
Øivind Midttun ◽  
Per Magne Ueland ◽  
Stein Emil Vollset ◽  
...  
Keyword(s):  
Immune Activation ◽  
Plasma Concentrations ◽  
Correlation Coefficients ◽  
Interferon Γ ◽  
Kynurenine Pathway ◽  
Additive Models ◽  
B Vitamins ◽  
Health Study ◽  
Xanthurenic Acid ◽  
Hydroxyanthranilic Acid

Vitamins B2and B6are cofactors in the kynurenine pathway. Many of the kynurenines are neuroactive compounds with immunomodulatory effects. In the present study, we aimed to investigate plasma concentrations of vitamins B2and B6as determinants of kynurenines and two markers of interferon-γ-mediated immune activation (kynurenine:tryptophan ratio (KTR) and neopterin). We measured the concentrations of vitamins B2and B6vitamers, neopterin, tryptophan and six kynurenines (i.e. kynurenine, anthranilic acid, kynurenic acid, 3-hydroxykynurenine, 3-hydroxyanthranilic acid and xanthurenic acid) in plasma from 7051 individuals. Dietary intake of vitamins B2and B6was assessed using a validated FFQ. Associations were investigated using partial Spearman's correlations, generalised additive models, and segmented or multiple linear regression. The B2vitamer, riboflavin, was positively associated with 3-hydroxyanthranilic acid and xanthurenic acid, with correlation coefficients, as obtained by segmented regression, of 0·20 (95 % CI 0·16, 0·23) and 0·24 (95 % CI 0·19, 0·28), at riboflavin concentrations below the median value (13·0 nmol/l). The vitamin B6vitamer, pyridoxal 5′-phosphate (PLP), was positively associated with most kynurenines at PLP concentrations < 39·3–47·0 nmol/l, and inversely associated with 3-hydroxykynurenine with the association being more prominent at PLP concentrations < 18·9 nmol/l. Riboflavin and PLP were associated with xanthurenic acid only at relatively low, but normal concentrations of both vitamers. Lastly, PLP was negatively correlated with neopterin and KTR. These results demonstrate the significant and complex determination of kynurenine metabolism by vitamin status. Future studies on B-vitamins and kynurenines in relation to chronic diseases should therefore integrate data on relevant biomarkers related to B-vitamins status and tryptophan metabolism.

scholarly journals Postpartum corticosterone and fluoxetine shift the tryptophan-kynurenine pathway in dams

2021 ◽  
Author(s):  
Wansu Qiu ◽  
Kimberly A. Go ◽  
Yvonne Lamers ◽  
Liisa A. M. Galea
Keyword(s):  
Selective Serotonin Reuptake Inhibitors ◽  
De Novo ◽  
Kynurenine Pathway ◽  
Xanthurenic Acid ◽  
Plasma Tryptophan ◽  
Limited Efficacy ◽  
Metabolite Concentrations ◽  
Antidepressant Efficacy ◽  
Enzyme Cofactors ◽  
Hydroxyanthranilic Acid

AbstractPerinatal depression (PND) affects 15% of mothers. Selective serotonin reuptake inhibitors (SSRIs) are currently the first-line of treatment for PND, but are not always efficacious. Previously, we found significant reductions in plasma tryptophan concentrations and higher hippocampal proinflammatory cytokine, IL-1β levels, due to maternal SSRI treatment. Both inflammation and tryptophan-kynurenine metabolic pathway (TKP) are associated with SSRI efficacy in individuals with major depressive disorder (MDD). TKP is divided into neuroprotective and neurotoxic pathways. Higher metabolite concentrations of the neurotoxic pathway are associated with depression onset and implicated in SSRI efficacy. Metabolites in TKP were investigated in a rodent model of de novo postpartum depression (PPD) given treatment with the SSRI, fluoxetine (FLX). Dams were administered corticosterone (CORT) (40mg/kg, s.c.), and treated with the SSRI, fluoxetine (FLX) (10mg/kg, s.c.), during the postpartum for 22 days after parturition. Plasma TKP metabolite concentrations were quantified on the last day of treatment. Maternal postpartum CORT increased neurotoxic metabolites and co-enzyme/cofactors in dams (3-hydroxykynurenine, 3-hydroxyanthranilic acid, vitamin B2, flavin adenine dinucleotide). The combination of both CORT and FLX shifted the neuroprotective-to-neurotoxic ratio towards neurotoxicity. Postpartum FLX decreased plasma xanthurenic acid concentrations. Together, our data indicate higher neurotoxic TKP expression due to maternal postpartum CORT treatment, similar to clinical presentation of MDD. Moreover, maternal FLX treatment showed limited efficacy to influence TKP metabolites, which may correspond to its limited efficacy to treat depressive-like endophenotypes. Overall suggesting changes in TKP may be used as a biomarker of de novo PPD and antidepressant efficacy and targeting this pathway may serve as a potential therapeutic target.

scholarly journals Stochastic Resonance Activity Influences Serum Tryptophan Metabolism in Healthy Human Subjects

2011 ◽  
Vol 4 ◽  
pp. IJTR.S7986 ◽  
Author(s):  
Berthold Kepplinger ◽  
Halina Baran ◽  
Brenda Sedlnitzky-Semler ◽  
Nagy-Roland Badawi ◽  
Helene Erhart
Keyword(s):  
Stochastic Resonance ◽  
Anthranilic Acid ◽  
Kynurenic Acid ◽  
Human Subjects ◽  
Serum Levels ◽  
Kynurenine Pathway ◽  
Tryptophan Metabolism ◽  
Healthy Human ◽  
Neuropsychiatric Diseases ◽  
Exercise Activity

Background Stochastic resonance therapy (SRT) is used for rehabilitation of patients with various neuropsychiatric diseases. An alteration in tryptophan metabolism along the kynurenine pathway has been identified in the central and peripheral nervous systems in patients with neuroinflammatory and neurodegenerative diseases and during the aging process. This study investigated the effect of SRT as an exercise activity on serum tryptophan metabolites in healthy subjects. Methods Serum L-tryptophan, L-kynurenine, kynurenic acid, and anthranilic acid levels were measured one minute before SRT and at one, 5, 15, 30, and 60 minutes after SRT. We found that SRT affected tryptophan metabolism. Serum levels of L-tryptophan, L-kynurenine, and kynurenic acid were significantly reduced for up to 60 minutes after SRT. Anthranilic acid levels were characterized by a moderate, non significant transient decrease for up to 15 minutes, followed by normalization at 60 minutes. Tryptophan metabolite ratios were moderately altered, suggesting activation of metabolism after SRT. Lowering of tryptophan would generally involve activation of tryptophan catabolism and neurotransmitter, protein, and bone biosynthesis. Lowering of kynurenic acid by SRT might be relevant for improving symptoms in patients with neuropsychiatric disorders, such as Parkinson's disease, Alzheimer's disease, schizophrenia, and depression, as well as certain pain conditions.

scholarly journals Tryptophan metabolism in the central nervous system: medical implications

2006 ◽  
Vol 8 (20) ◽  
pp. 1-27 ◽  
Author(s):  
Jon P. Ruddick ◽  
Andrew K. Evans ◽  
David J. Nutt ◽  
Stafford L. Lightman ◽  
Graham A.W. Rook ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Molecular Mechanisms ◽  
Kynurenine Pathway ◽  
Tryptophan Metabolism ◽  
Integral Role ◽  
The Central Nervous System ◽  
Acquired Immunodeficiency ◽  
Hydroxyanthranilic Acid ◽  
Immunodeficiency Syndrome

The metabolism of the amino acid l-tryptophan is a highly regulated physiological process leading to the generation of several neuroactive compounds within the central nervous system. These include the aminergic neurotransmitter serotonin (5-hydroxytryptamine, 5-HT), products of the kynurenine pathway of tryptophan metabolism (including 3-hydroxykynurenine, 3-hydroxyanthranilic acid, quinolinic acid and kynurenic acid), the neurohormone melatonin, several neuroactive kynuramine metabolites of melatonin, and the trace amine tryptamine. The integral role of central serotonergic systems in the modulation of physiology and behaviour has been well documented since the first description of serotonergic neurons in the brain some 40 years ago. However, while the significance of the peripheral kynurenine pathway of tryptophan metabolism has also been recognised for several decades, it has only recently been appreciated that the synthesis of kynurenines within the central nervous system has important consequences for physiology and behaviour. Altered kynurenine metabolism has been implicated in the pathophysiology of conditions such as acquired immunodeficiency syndrome (AIDS)-related dementia, Huntington's disease and Alzheimer's disease. In this review we discuss the molecular mechanisms involved in regulating the metabolism of tryptophan and consider the medical implications associated with dysregulation of both serotonergic and kynurenine pathways of tryptophan metabolism.

scholarly journals The influence of D. melanogaster mutations of the kynurenine pathway of tryptophan metabolism on locomotor behavior and expression of genes belonging to glutamatergic and cholinergic systems

2011 ◽  
Vol 9 (2) ◽  
pp. 65-73
Author(s):  
Gennady A Zakharov ◽  
Alexander V Zhuravlev ◽  
Tatyana L Payalina ◽  
Nikolay G Kamyshev ◽  
Elena V Savvateeva-Popova
Keyword(s):  
Kynurenic Acid ◽  
Kynurenine Pathway ◽  
Locomotor Behavior ◽  
Tryptophan Metabolism ◽  
General Level ◽  
Sharp Reduction ◽  
Expression Of Genes ◽  
Age Related ◽  
Signal Cascades ◽  
Age Related Changes

Disbalance of kynurenines produced by Drosophila mutations of the kynurenine pathway of tryptophan metabolism influences the locomotor behavior in larvae. The most pronounced is the effect of accumulation of kynurenic acid in the mutant cinnabar manifested as sharp reduction of general level of locomotor activity. The mutations seem to act through modulatory influences of kynurenines on signal cascades governed by ionotropic glutamatergic and cholinergic receptors. Expression of receptor genes in the mutants shows age-related changes pointing to gradual evolvement of consequences of kynurenines disbalance.

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