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Kynurenic acid

Fernanda Silva Ferreira, Helena Biasibetti-Brendler, Paula Pierozan, Felipe Schmitz, Carolina Gessinger Bertó, Caroline Acauan Prezzi, Vanusa Manfredini, Angela T S Wyse
Kynurenic acid (KYNA) and quinolinic acid (QUIN) are metabolites produced in the degradation of tryptophan and have important neurological activities. KYNA/QUIN ratio changes are known to be associated with central nervous system disorders, such Alzheimer, Parkinson, and Huntington diseases. In the present study, we investigate the ability of KYNA in prevent the first events preceding QUIN-induced neurodegeneration in striatal slices of rat. We evaluated the protective effect of KYNA on oxidative status (reactive oxygen species production, antioxidant enzymes activities, lipid peroxidation, nitrite levels, protein and DNA damage, and iNOS immunocontent), mitochondrial function (mitochondrial mass, membrane potential, and respiratory chain enzymes), and Na+ ,K+ -ATPase in striatal slices of rats treated with QUIN...
March 21, 2018: Molecular Neurobiology
Gayan S Jayawickrama, Alireza Nematollahi, Guanchen Sun, W Bret Church
Kynurenine aminotransferase-II (KAT-II) is a pyridoxal 5'-phosphate (PLP)-dependent enzyme that acts in the tryptophan metabolic pathway by catalyzing the transamination of kynurenine into kynurenic acid (KYNA). It is one of four isoforms in the KAT family, of which it is the primary homologue responsible for KYNA production in the mammalian brain. KAT-II is targeted for inhibition as KYNA is implicated in diseases such as schizophrenia, where it is found in elevated concentrations. Previously, many different approaches have been taken to develop KAT-II inhibitors, and herein fragment-based drug design (FBDD) approaches have been exploited to provide further lead compounds that can be designed into novel inhibitors...
March 1, 2018: SLAS Discovery
Peter Hertelendy, Jozsef Toldi, Ferenc Fulop, Laszlo Vecsei
Ischemic stroke is one of the leading causes of mortality and permanent disability in developed countries. Stroke induces massive glutamate release, which in turn causes N-Methyl-D-aspartate (NMDA) receptor over-excitation and thus calcium overload in neurons leading to cell death via apoptotic cascades. The kynurenine pathway is a complex enzymatic cascade of tryptophan catabolism, generating various neuroactive metabolites. One metabolite, kynurenic acid (KYNA), is a potent endogenous NMDA glutamate receptor antagonist, making it a possible therapeutic tool to decrease excitotoxicity and neuroinflammation...
March 12, 2018: Current Medicinal Chemistry
Buranee Kanchanatawan, Sira Sriswasdi, Supaksorn Thika, Sunee Sirivichayakul, André F Carvalho, Michel Geffard, Marta Kubera, Michael Maes
Deficit schizophrenia is characterized by neurocognitive impairments and changes in the patterning of IgA/IgM responses to plasma tryptophan catabolites (TRYCATs). In the current study, supervised pattern recognition methods, including logistic regression analysis (LRA), Support Vector Machine (SVM), and Soft Independent Modeling of Class Analogy (SIMCA), were used to examine whether deficit schizophrenia is a discrete diagnostic class with respect to Consortium To Establish a Registry for Alzheimer's disease (CERAD) and Cambridge Neuropsychological Test Automated Battery (CANTAB) tests and IgA/IgM responses to noxious (NOX) and generally more protective (PRO) TRYCATs...
March 11, 2018: Metabolic Brain Disease
Joshua Chiappelli, Francesca M Notarangelo, Ana Pocivavsek, Marian A R Thomas, Laura M Rowland, Robert Schwarcz, L Elliot Hong
Abnormalities in the kynurenine pathway (KP) of tryptophan degradation, leading to the dysfunction of neuroactive KP metabolites in the brain, have been implicated in the pathophysiology of schizophrenia (SZ). One plausible mechanism involves dysregulation of various pro-inflammatory cytokines associated with the disease, which affect indoleamine-2,3-dioxygenase (IDO), a key enzyme for tryptophan to kynurenine conversion. In order to test this hypothesis directly, we measured plasma levels of the major KP metabolites kynurenine and kynurenic acid (KYNA), as well as four major cytokines, in a sample of 106 SZ patients and 104 control participants...
February 27, 2018: Neuropsychopharmacology: Official Publication of the American College of Neuropsychopharmacology
Fabienne Aregger, Dominik E Uehlinger, Gerhard Fusch, Aldin Bahonjic, Rene Pschowski, Michael Walter, Joerg C Schefold
BACKGROUND: Acute kidney injury (AKI) is often observed in critically ill patients and is associated with high morbidity and mortality. Non-recovery from AKI has a negative impact on the prognosis of affected patients and early risk stratification seems key to improve clinical outcomes. We analyzed metabolites of a conserved key inflammatory pathway (i.e. tryptophan degradation pathway) in serial urine samples of patients with AKI. METHODS: One hundred twelve ICU patients with AKI were included in a prospective observational analysis...
February 26, 2018: BMC Nephrology
Dénes Zádori, Gábor Veres, Levente Szalárdy, Péter Klivényi, László Vécsei
The pathomechanism of Alzheimer's disease (AD) certainly involves mitochondrial disturbances, glutamate excitotoxicity, and neuroinflammation. The three main aspects of mitochondrial dysfunction in AD, i.e., the defects in dynamics, altered bioenergetics, and the deficient transport, act synergistically. In addition, glutamatergic neurotransmission is affected in several ways. The balance between synaptic and extrasynaptic glutamatergic transmission is shifted toward the extrasynaptic site contributing to glutamate excitotoxicity, a phenomenon augmented by increased glutamate release and decreased glutamate uptake...
2018: Journal of Alzheimer's Disease: JAD
Patrycja Nowicka-Stążka, Ewa Langner, Waldemar Turski, Wojciech Rzeski, Jolanta Parada-Turska
BACKGROUND: Previously, we have demonstrated that kynurenic acid (KYNA), an endogenous metabolite of tryptophan formed along kynurenine pathway, is present in synovial fluid of rheumatoid arthritis (RA) and osteoarthritis (OA) patients. In this study, the goal was to investigate the presence of quinaldic acid (QUDA), a putative metabolite of KYNA, in synovial fluid of RA and OA patients. METHODS: The effect of QUDA on proliferation and motility of synovial fibroblasts and its interaction with KYNA were determined in vitro...
October 3, 2017: Pharmacological Reports: PR
A P Allen, M Naughton, J Dowling, A Walsh, R O'Shea, G Shorten, L Scott, D M McLoughlin, J F Cryan, G Clarke, T G Dinan
Current first-line antidepressants can take weeks or months to decrease depressive symptoms. Low dose ketamine, an N-methyl-D-aspartate (NMDA) receptor antagonist, shows potential for a more rapid antidepressant effect, with efficacy also evident in previously treatment-resistant populations. However, a greater understanding of the physiological mechanisms underlying such effects is required. We assessed the potential impact of ketamine infusion on neurobiological drivers of kynurenine pathway metabolism in major depression (HPA axis hyperactivity, inflammation) in patients with treatment-resistant depression compared to gender-matched healthy controls...
February 10, 2018: Journal of Psychiatric Research
Aleksey Etinger, Kumar, William Ackley, Leland Soiefer, Jonathan Chun, Prabjhot Singh, Eric Grossman, Albert Matalon, Robert S Holzman, Bjorn Meijers, Jerome Lowenstein
BACKGROUND: There is growing evidence that the accumulation of protein- bound uremic retention solutes, such as indoxyl sulfate, p-cresyl sulfate and kynurenic acid, play a role in the accelerated cardiovascular disease seen in patients undergoing chronic hemodialysis. Protein-binding, presumably to albumin, renders these solutes poor-dialyzable. We previously observed that the free fraction of indoxyl sulfate was markedly reduced at the end of hemodialysis. We hypothesized that solute binding might be pH-dependent and attributed the changes in free solute concentration to the higher serum pH observed at the end of standard hemodialysis with dialysis buffer bicarbonate concentration greater than 35 mmol/L...
2018: PloS One
Jing Gao, Kang Xu, Hongnan Liu, Gang Liu, Miaomiao Bai, Can Peng, Tiejun Li, Yulong Yin
The gut microbiota influences the health of the host, especially with regard to gut immune homeostasis and the intestinal immune response. In addition to serving as a nutrient enhancer, L-tryptophan (Trp) plays crucial roles in the balance between intestinal immune tolerance and gut microbiota maintenance. Recent discoveries have underscored that changes in the microbiota modulate the host immune system by modulating Trp metabolism. Moreover, Trp, endogenous Trp metabolites (kynurenines, serotonin, and melatonin), and bacterial Trp metabolites (indole, indolic acid, skatole, and tryptamine) have profound effects on gut microbial composition, microbial metabolism, the host's immune system, the host-microbiome interface, and host immune system-intestinal microbiota interactions...
2018: Frontiers in Cellular and Infection Microbiology
A Papp, R Hartwell, M Evans, A Ghahary
Scarring is a consequence of biological tissue repair following trauma. Currently there are no generally agreed ways to prevent scarring. Recently, kynurenic acid has shown to be a potent modulator of extracellular matrix deposition and remodeling. Kynurenic acid can reduce matrix deposition and other fundamental characteristics of fibrosis in vitro and in vivo. Specifically, kynurenic acid has shown to increase MMP-1 activity and subsequently reduce collagen deposition in a rabbit ear scar model. In the current study kynurenic acid cream in different concentrations was topically applied on healthy skin on volunteers to assess skin reactions and skin sensitivity in both acute and chronic application settings...
February 5, 2018: Journal of Pharmaceutical Sciences
Qibin Qi, Simin Hua, Clary B Clish, Justin M Scott, David B Hanna, Tao Wang, Sabina A Haberlen, Sanjiv J Shah, Marshall J Glesby, Jason M Lazar, Robert D Burk, Howard N Hodis, Alan L Landay, Wendy S Post, Kathryn Anastos, Robert C Kaplan
Background: It is unknown whether disrupted tryptophan catabolism is associated with cardiovascular disease (CVD) in HIV-infected individuals. Methods: Plasma tryptophan and kynurenic acid were measured among 737 women and men (520 HIV+, 217 HIV-) from the Women's Interagency HIV Study and the Multicenter AIDS Cohort Study. Repeated B-mode carotid artery ultrasound imaging was obtained among these participants in 2004-2013. We examined associations of baseline plasma tryptophan, kynurenic acid, and kynurenic acid-to-tryptophan (KYNA/TRP) ratio, a measure of tryptophan catabolism, with risk of carotid artery plaque...
February 3, 2018: Clinical Infectious Diseases: An Official Publication of the Infectious Diseases Society of America
Leandro Z Agudelo, Duarte M S Ferreira, Igor Cervenka, Galyna Bryzgalova, Shamim Dadvar, Paulo R Jannig, Amanda T Pettersson-Klein, Tadepally Lakshmikanth, Elahu G Sustarsic, Margareta Porsmyr-Palmertz, Jorge C Correia, Manizheh Izadi, Vicente Martínez-Redondo, Per M Ueland, Øivind Midttun, Zachary Gerhart-Hines, Petter Brodin, Teresa Pereira, Per-Olof Berggren, Jorge L Ruas
The role of tryptophan-kynurenine metabolism in psychiatric disease is well established, but remains less explored in peripheral tissues. Exercise training activates kynurenine biotransformation in skeletal muscle, which protects from neuroinflammation and leads to peripheral kynurenic acid accumulation. Here we show that kynurenic acid increases energy utilization by activating G protein-coupled receptor Gpr35, which stimulates lipid metabolism, thermogenic, and anti-inflammatory gene expression in adipose tissue...
February 6, 2018: Cell Metabolism
Mihir Vohra, George A Lemieux, Lin Lin, Kaveh Ashrafi
A general feature of animal aging is decline in learning and memory. Here we show that in Caenorhabditis elegans, a significant portion of this decline is due to accumulation of kynurenic acid (KYNA), an endogenous antagonist of neural N-methyl-D-aspartate receptors (NMDARs). We show that activation of a specific pair of interneurons either through genetic means or by depletion of KYNA significantly improves learning capacity in aged animals even when the intervention is applied in aging animals. KYNA depletion also improves memory...
January 31, 2018: Genes & Development
Katalin Sas, Elza Szabó, László Vécsei
In this review, the potential causes of ageing are discussed. We seek to gain insight into the main physiological functions of mitochondria and discuss alterations in their function and the genome, which are supposed to be the central mechanisms in senescence. We conclude by presenting the potential modulating role of the kynurenine pathway in the ageing processes. Mitochondrial dynamics are supposed to have important physiological roles in maintaining cell homeostasis. During ageing, a decrease in mitochondrial dynamics was reported, potentially compromising the function of mitochondria...
January 17, 2018: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Eszter Lajkó, Bernadett Tuka, Ferenc Fülöp, István Krizbai, József Toldi, Kálmán Magyar, László Vécsei, László Kőhidai
The neuroprotective actions of kynurenic acid (KYNA) and its derivatives in several neurodegenerative disorders [characterized by damage to the cerebral endothelium and to the blood-brain barrier (BBB)] are well established. Cell-extracellular matrix (ECM) adhesion is supposedly involved in recovery of impaired cerebral endothelium integrity (endothelial repair). The present work aimed to investigate the effects of KYNA and its synthetic derivatives on cellular behaviour (e.g. adhesion and locomotion) and on morphology of the GP8 rat brain endothelial cell line, modeling the BBB endothelium...
January 13, 2018: Journal of Neural Transmission
Kathrin Arnhard, Florian Pitterl, Barbara Sperner-Unterweger, Dietmar Fuchs, Therese Koal, Herbert Oberacher
Tryptophan (TRP) catabolism via the kynurenine pathway is considered to represent a major link between inflammation and various diseases, including neurodegenerative disorders, depression, schizophrenia, multiple sclerosis, cardiovascular disease, and cancer. The kynurenine pathway and levels of TRP and its metabolites kynurenine (KYN), kynurenic acid (KYNA) and quinolinic acid (QUIN) are well regulated under physiological conditions but may be altered as part of the activated immune response. A simple, sensitive and specific liquid chromatography-time of flight mass spectrometry method was developed for determining levels of the four compounds in human plasma samples...
January 12, 2018: Electrophoresis
Michal Majewski, Natalia Kasica, Anna Jakimiuk, Piotr Podlasz
Defects in tryptophan metabolism on the l-kynurenine pathway (KP) are implicated in a number of human diseases, including chronic kidney disease, brain edema or injury, tuberculosis and malaria - as well as cancer, neurodegenerative and autoimmune disorders. However, it is unclear to what extent detrimental effects of exposure to tryptophan metabolites might impact the early development of organism. Thus, this study examined the effects of KP exposure in zebrafish embryos starting at the blastula period (4hpf) and the segmentation stage (24hpf)...
January 6, 2018: Toxicology and Applied Pharmacology
Marisol Maya-López, María Verónica Mireles-García, Monserrat Ramírez-Toledo, Ana Laura Colín-González, Sonia Galván-Arzate, Isaac Túnez, Abel Santamaría
The mechanisms by which the heavy metal thallium (Tl+) produces toxicity in the brain remain unclear. Herein, isolated synaptosomal/mitochondrial P2 crude fractions from adult rat brains were exposed to Tl+ (5-250 μM) for 30 min. Three toxic endpoints were evaluated: mitochondrial dysfunction, lipid peroxidation, and Na+/K+-ATPase activity inhibition. Concentration-response curves for two of these endpoints revealed the optimum concentration of Tl+ to induce damage in this preparation, 5 μM. Toxic markers were also estimated in preconditioned synaptosomes incubated in the presence of the N-methyl-D-aspartate receptor antagonist kynurenic acid (KYNA, 50 μM), the cannabinoid receptor agonist WIN 55,212-2 (1 μM), or the antioxidant S-allyl-L-cysteine (SAC, 100 μM)...
January 8, 2018: Neurotoxicity Research
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