Comparison of serum kynurenine pathway metabolites between patients with first-episode and recurrent major depressive disorder / 四川精神卫生

BackgroundThe pathogenesis of depression remains not fully understood， and previous studies have suggested that the kynurenine pathway （KP） plays an important role in the pathogenesis of major depressive disorder. ObjectiveTo study the difference in serum KP metabolites level between patients with first-episode and recurrent major depressive disorder， and to testify the correlation between KP metabolites level with the severity of depressive symptoms， so as to provide references for the prevention of recurrence. MethodsA total of 136 patients with major depressive disorder who attended the outpatient clinics of the Affiliated Brain Hospital of Guangzhou Medical University from November 2016 to December 2018 and met the diagnostic criteria of the Diagnostic and Statistical Manual of Mental Disorders， fifth edition （DSM-5） diagnostic criteria were included， including 62 patients in the first-episode group and 74 patients in the recurrent group. Meanwhile， 60 healthy subjects were included as control group. All patients were assessed by Hamilton Depression Scale-17 item （HAMD-17）， and serum concentrations of tryptophan （TRP）， kynurenine （KYN） and kynurenic acid （KYNA） were measured by liquid chromatography tandem mass spectrometry （LC-MS/MS）. Then the correlation of HAMD-17 total score and individual item scores with the levels of KP metabolites was tested using partial correlation coefficient. ResultsCompared with the control group， the first-episode group and recurrent group showed a marked decline in TRP concentration （t=-3.044， -4.477， P<0.05 or 0.01） and an increase in KYN/TRP ratio （t=2.343， 3.644， P<0.05 or 0.01）， with significant differences. The KYNA concentrations （t=2.490， 2.636， P<0.05 or 0.01） and KYNA/KYN ratio （t=2.894， 2.616， P<0.01） in first-episode group and control group were notably elevated compared to recurrent group， with statistical difference. Partial correlation analysis in patients with first-episode major depressive disorder demonstrated that KYN/TRP ratio was positively correlated with the HAMD-17 anxiety/somatization factor score （r=0.261， P<0.05）， and KYNA/KYN ratio was negatively correlated with HAMD-17 total score and block factor score （r=-0.286， -0.282， P<0.05）. In patients with recurrent major depressive disorder， KYN/TRP ratio was positively correlated with HAMD-17 anxiety/somatization factor score （r=0.280， P<0.05）. ConclusionKP metabolites in serum differ between first-episode and recurrent major depressive disorder patients， and patients with recurrent episodes experience severe KP metabolite abnormalities. Therefore， KP metabolites are considered to be potential biomarker candidates to assist clinicians in the diagnosis and recurrent prediction of major depressive disorder. ［Funded by National Key Research and Development Program Precision Medicine Research Project （number， 2016YFC0906300）］

Tryptophan metabolism involved by gut microbiota and ischemic stroke / 国际脑血管病杂志

Tryptophan is one of the essential amino acids of human body. Its metabolites 5-hydroxytryptamine, kynurenine, tryptamine, and indole derivatives have the functions of immune regulation, nerve regulation, anti-inflammatory, anti-oxidation, anti-cancer, and metabolic regulation. In recent years, it has been found that dysregulation of tryptophan metabolism is closely associated with the onset and prognosis of ischemic stroke, and intestinal flora plays an important role in the regulation of tryptophan metabolism. This article reviews the research progress on the role and mechanism of tryptophan metabolism involved by intestinal flora in ischemic brain injury, and provides a new perspective for future basic and clinical research.

The functions and mechanisms of kynurenine pathway in cognitive dysfunction / 中国医师杂志

Tryptophan (TRP) is an essential amino-acid and the precursor of many signaling molecules. Under the catalysis of indoleamine 2, 3-dioxygenase, kynurenine pathway can form its metabolites uroquinolinic acid and quinolinic acid, which is the main channel of TRP metabolism.Through different mechanisms in N-methyl-D-aspartate receptor, they participate in nervous modulation, affect cognitive processes and play an important role in many central nervous system diseases development. Kynurenine pathway is different under physiological and pathological conditions. In addition, there are many rate-limiting enzymes in the kynurenine pathway, which can interfere kynurenine pathway. This article reviews the relationship between tryptophan/kynurenine pathway and cognitive dysfunction.

Yixin Ningshen Tablet Alleviates Comorbidity of Myocardial Infarction and Depression by Enhancing Myocardial Energy Metabolism and Increasing Availability of Monoamine Neurotransmitter / 中国结合医学杂志

OBJECTIVE@#To investigate the therapeutic effect of Yixin Ningshen Tablet (YXNS) on comorbidity of myocardial infarction (MI) and depression in rats and explore the underlying mechanism.@*METHODS@#The Sprague-Dawley rats were randomly divided into 5 groups with 7 rats in each group according to their weights, including control, model, fluoxetine (FLXT, 10 mg/kg), low-dose YXNS (LYXNS, 100 mg/kg), and high-dose YXNS (HYXNS, 300 mg/kg) groups. All rats were pretreated with corresponding drugs for 12 weeks. The rat model of MI and depression was constructed by ligation of left anterior descending coronary artery and chronic mild stress stimulation. The echocardiography, sucrose preference test, open field test, and forced swim test were performed. Myocardial infarction (MI) area and myocardial apoptosis was also detected. Serum levels of interleukin (IL)-6, IL-1β, tumor necrosis factor-α (TNF-α), 5-hydroxytryptamine (5-HT), adrenocorticotrophic hormone (ACTH), corticosterone (CORT), and norepinephrine (NE) were determined by enzyme linked immunosorbent assay. The proteins of adenosine 5'-monophosphate -activated protein kinase (AMPK), p-AMPK, peroxisome proliferator-activated receptor gamma coactivator-1α (PGC-1α), and nuclear respiratory factor 1 (NRF1) in heart were detected by Western blot analysis. The expression levels of TNF-α, IL-6, indoleamine 2,3-dioxygenase (IDO1), kynurenine 3-monooxygenase (KMO), and kynureninase (KYNU) in hippocampus were detected by real-time quantitative polymerase chain reaction.@*RESULTS@#Compared with the model group, the cardiac function of rats treated with YXNS improved significantly (P<0.01). Meanwhile, YXNS effectively reduced MI size and cardiomyocytes apoptosis of rats (P<0.01 or P<0.05), promoted AMPK phosphorylation, and increased PGC-1α protein expression (P<0.01 or P<0.05). HYXNS significantly increased locomotor activity of rats, decreased the levels of TNF-α, IL-6 and IL-1β, and increased the serum levels of 5-HT, NE, ACTH, and CORT (all P<0.05). Moreover, HYXNS decreased the mRNA expressions of IDO1, KMO and KYNU (P<0.05).@*CONCLUSIONS@#YXNS can relieve MI by enhancing myocardial energy metabolism. Meanwhile, YXNS can alleviate depression by resisting inflammation and increasing availability of monoamine neurotransmitters. It may be used as a potential drug to treat comorbidity of MI and depression.

Significance and Prospect of Tryptophan Metabolism in Treatment of Tumor Immune Checkpoint Inhibitors / 肿瘤防治研究

Although immune checkpoint inhibitors (ICIs) have great breakthrough in cancer treatment in recent years, most patients have not benefited from it on account of immune microenvironment. Studies have shown that tryptophan metabolism is not only involved in the formation of tumor immunosuppressive microenvironment but also plays an important role in the therapeutic application of ICIs. At present, inhibiting the kynurenine pathway of tryptophan metabolism is now in various stages of clinical trials, while the other two metabolic pathways, 5-HT and the indole pathway, also have aroused wide concern. This article reviews the latest developments in this field.

Sinalização e metabolismo celulares durante a diferenciação de linfócitos B humanos em secretores de anticorpos na presença do vírus da Dengue in vitro e em pacientes com Dengue / B cell signaling and metabolism during antibody-secreting cell differentiation in the presence of Dengue virus in vitro and in Dengue patients

A Dengue é uma doença viral sistêmica, transmitida por mosquitos, que afeta anualmente cerca de 100 milhões de pessoas em todo o mundo. Causada por quatro sorotipos do vírus da Dengue (DENV), suas manifestações clínicas podem variar de assintomáticas à formas que podem levar a óbito. Curiosamente, os pacientes com Dengue apresentam uma resposta exacerbada das células secretoras de anticorpos (ASCs) no sangue cerca de sete dias após o início dos sintomas. A frequência dessas ASCs induzidas pelo DENV representa mais de 50% de todas as células B circulantes no sangue. Essa quantificação é maior que aquelas encontradas em outras infecções virais, contextos de imunização e até mesmo em pacientes com neoplasias de ASCs. Além disso, a magnitude dessa resposta transitória se correlaciona com a gravidade da doença. Então, como a infecção pelo DENV induz essa resposta enorme? Para responder à essa pergunta, combinamos abordagens in vitro e in silico. Células mononucleares do sangue periférico (PBMCs) obtidas de indivíduos saudáveis foram cultivadas in vitro durante sete dias na presença do DENV ou mitógenos. Após a estimulação pelo DENV, as células B presentes nas PBMCs foram capazes de se diferenciarem em ASCs, tanto fenotipicamente quanto funcionalmente, em magnitude similar àquelas estimuladas com mitógenos. Essa diferenciação demonstrou ser dependente da presença de outras células contidas nas PBMCs, assim como do contato célula-célula. Embora ambos os estímulos tenham sido capazes de induzir a diferenciação de ASCs, eles diferiram metabolicamente e transcricionalmente. PBMCs estimuladas pelo DENV apresentaram um maior consumo de triptofano, associado à maior expressão de IDO1 e IDO2 e maior síntese de quinurenina, bem como maiores expressões de IL-10, BAFF e SYK. Ainda, as concentrações de quinurenina foram positivamente correlacionadas com a enumeração de ASCs nessas culturas. Dados de transcriptoma públicos de pacientes com Dengue também suportam esses achados. Outros flavivírus, como o vírus Zika e a cepa vacinal da Febre Amarela não foram capazes de induzir a mesma magnitude de diferenciação das células B em ASCs in vitro. Tão pouco apresentaram correlação entre a enumeração de ASCs e a síntese de quinurenina. Por fim, através da construção de uma hipotética via de diferenciação de células B em ASCs durante infecção pelo DENV, através da combinação de dados da literatura e transcriptomas públicos, demonstramos que moléculas relacionadas à via do STAT3 (IL-10, IL-6, IRF4 e BLIMP1) estão mais expressas nos pacientes infectados e moléculas que respondem aos sinais de cálcio (Calcineurina, NFATC1, DOK3 e GRB2) estão menos expressas nos pacientes infectados. Esses dados proporcionam um melhor entendimento da resposta de células B durante a infeção pelo DENV, particularmente sobre como o metabolismo e a sinalização das células B estão conectados nesse processo

Dengue is a mosquito-borne viral disease that affects annually about 100 million people worldwide. Caused by four Dengue virus (DENV) serotypes, it ranges from asymptomatic to life threatening forms. Curiously, Dengue patients present an exacerbated blood antibody-secreting cell (ASCs) response around seven days after the symptoms onset. The frequency of those DENV-induced ASCs represents more than 50% of all circulating blood B cells. This is greater than found in others viral infections, immunization contexts and even in ASCs related-leukemia patients. Moreover, the magnitude of that transitory response correlates with the disease severity. So, how does the DENV infection induce this enormous response? In order to answer this question we have combined in vitro and in silico approaches. Peripheral blood mononuclear cells (PBMC) obtained from healthy individuals were cultured in vitro during seven days in the presence of DENV or mitogens. Upon the DENV stimulation, PBMC-contained B cells were able to differentiate phenotypically and functionally into ASCs, both phenotypically and functionally, in a similar magnitude than mitogen-stimulated cells. This differentiation was demonstrated to be dependent of the presence of the remaining PBMCs, as well as of the cell-cell contact. Although both stimuli were able to induce the ASCs differentiation, they differed metabolically and transcriptionally. DENV-stimulated PBMCs showed higher tryptophan consumption, associated with higher IDO1 and IDO2 expression and higher kynurenine synthesis, as well as higher IL-10, BAFF and SYK expressions compared to mitogen-exposed counterparts. Additionally, the kynurenine concentrations were positively correlated with the ASCs-enumeration in those cultures. Public transcriptome data supports these findings as well. Other flaviviruses, such as Zika virus and the attenuated vaccine Yellow Fever were not able to induce the same magnitude of ASCs differentiation in vitro. Hence, they did not present a correlation between the number of generated ASCs and the supernatant kynurenine levels. Based on the combination of the literature and public transcriptome data, we have constructed a hypothetical B cell differentiation pathway that might be occurring during DENV infection. It displays that STAT3 pathway-related molecules (IL-10, IL-6, IRF4 and BLIMP1) are more expressed in Dengue patients and molecules that respond to calcium signals (Calcineurin, NFATC1, DOK3 and GRB2) are less expressed in Dengue patients than in control. These data provide a better understanding of the B cell response elicited by DENV infection, particularly about how the B cell metabolism and signaling can be connected into this process

Ácido fólico em excesso: efeitos sobre o metabolismo das vitaminas B2 e B6, o catabolismo do triptofano e a resposta imune / Folic acid excess: effects on vitamin B2 and B6 metabolism, tryptophan catabolism and immune response

Introdução: A suplementação com ácido fólico (AF) é recomendada em algumas condições para evitar a deficiência de folato, como para mulheres no período periconcepcional e durante a gestação. Atualmente, existe uma preocupação quanto ao consumo excessivo de AF pela população pelo uso de suplementos com altas doses dessa vitamina. As vitaminas B6 e B2 agem como cofatores no metabolismo de um carbono, e o uso de altas doses de AF pode influenciar o metabolismo de ambas vitaminas e, consequentemente, interferir em metabolismos importantes das quais elas participam, como a via das quinureninas, e no sistema imune. Objetivo: Avaliar os efeitos da intervenção diária com uma alta dose de AF (5 mg) por 90 dias sobre marcadores do estado das vitaminas do complexo B, e as consequências sobre os metabólitos da via das quinureninas e o sistema imune em adultos saudáveis. Material e Métodos: 64 indivíduos saudáveis foram submetidos à intervenção diária com 5 mg de AF por 90 dias. Coletas de sangue foram realizadas antes (baseline) e após 45 e 90 dias de intervenção. As concentrações séricas de folato e vitamina B12 foram avaliadas por métodos microbiológicos. As concentrações séricas das vitaminas B6 (piridoxal 5'-fosfato (PLP), piridoxal (PL) e ácido 4-piridóxico (PA)), B2 (riboflavina e flavina mononucleotídeo (FMN)), B1 (tiamina e tiamina monofosfato (TMP)) e B3 (ácido nicotínico, nicotinamida e N1-metilnicotinamida), bem como de triptofano, quinurenina e metabólitos, foram avaliadas por LC-MS/MS. A proteína C-reativa ultrassensível (PCRus) foi determinada por imunoturbidimetria, e as concentrações séricas de interleucina (IL)-6, IL-8, IL-10, interferon gama (IFN-γ) e fator de necrose tumoral alfa (TNF-α) foram avaliadas por ensaio multiplex. A expressão de RNAm de DHFR (dihidrofolato redutase), MTHFR (metilenotetrahidrofolato redutase), IL8, TNFA e IFNG em leucócitos mononucleares (PBMC) foram avaliadas por PCR em tempo real. O número de células T regulatórias (Treg) (CD3+, CD4+, CD25high, FoxP3+, CD127-) foi avaliado após incubação dos PBMC com PMA e ionomicina ou veículo por 18h, por imunofenotipagem. Resultados: Houve um grande aumento das concentrações de folato sérico após 45 e 90 dias de intervenção com AF. Não houve diferença nas concentrações de vitamina B12 antes e após a intervenção. As concentrações séricas de PLP foram semelhantes antes e após a intervenção, entretanto, um aumento de PL sérico foi observado após 45 e 90 dias, e de PA após 45 dias, quando comparado ao baseline. Riboflavina e FMN foram maiores após 45 e 90 dias em relação ao baseline. A tiamina sérica foi menor após 45 dias, e as concentrações de TMP foram maiores após 90 dias quando comparados aos períodos anteriores. Não houve diferença nas concentrações de vitamina B3 antes e após a intervenção. Dentre os metabólitos da via das quinureninas, apenas o ácido antranílico apresentou aumento após 45 e 90 dias, enquanto o ácido picolínico diminuiu após 90 dias. PCRus, IL-6, IL-8, IL-10, IFN-γ e TNF-α séricos foram semelhantes no baseline e após a intervenção. Um aumento da expressão de RNAm de DHFR e TNFA foi observado após, respectivamente, 90 dias e 45 e 90 dias de intervenção. Após 90 dias de intervenção com AF, foi observada diminuição do número de células Treg após estímulo com PMA e ionomicina. Conclusão: O uso diário de 5 mg de AF foi associado a alterações nas concentrações séricas de marcadores do estado de vitaminas do complexo B e da via das quinureninas, bem como a diminuição do número de células Treg

Introduction: Folic acid (FA) supplementation is recommended in some conditions to avoid folate deficiency, as women during periconceptional period and pregnancy. Currently, there is a concern about the excessive consumption of FA by population by using supplements with high doses of this vitamin. Vitamins B6 and B2 are cofactors of enzymes of one carbon metabolism and, consequently, may disturb key metabolism in which they participate, as kynurenine pathway, and the immune system. Aim: To assess the effects of a daily intervention with high dose of FA (5 mg) for 90 days on biomarkers of complex B vitamins status and its outcomes in kynurenine pathway metabolites and immune system in healthy adults. Material and Methods: 64 healthy individuals were submitted to a daily intervention with 5 mg of FA for 90 days. Blood samples were collected before (baseline) and after 45 and 90 days of intervention. Serum folate and vitamin B12 were assessed by microbiological assays. Serum vitamin B6 (pyridoxal 5'-phosphate (PLP), pyridoxal (PL) and 4-pyridoxic acid (PA)), vitamin B2 (riboflavin and flavin mononucleotide (FMN)), vitamin B1 (thiamin and thiamin monophosphate)) and vitamin B3 (nicotinic acid, nicotinamide and N1-methylnicotinamide), as well as tryptophan, kynurenine and metabolites, were assessed by LC-MS/MS. C-reactive protein (hs-CPR) was assessed by immunoturbidimetry, and serum interleukin (IL)-6, IL-8, IL-10, interferon gamma (IFN-γ) and tumor necrosis factor alpha (TNF-α) were assessed by multiplex assay. Mononuclear leukocytes mRNA expression of DHFR (dihydrofolate reductase), MTHFR (methylenetetrahydrofolate reductase), IL8, TNFA and IFNG were assessed by real time PCR. Regulatory T Cell (Treg) number (CD3+, CD4+, CD25high, FoxP3+, CD127-) was determined after mononuclear leukocytes incubation with PMA and ionomycin or vehicle for 18h, by immunophenotyping. Results: A great increase on serum folate was observed after 45 and 90 days of FA intervention. No differences in serum vitamin B12 were observed before and after intervention. Serum PLP was similar before and after intervention, however, an increase in serum PL was observed after 45 and 90 days, and in PA after 45 days, when compared to baseline. Riboflavin and FMN were increased after 45 and 90 days than in baseline. Serum thiamine was decreased after 45 days than in baseline. Serum TMP was increased after 90 days when compared with previous timepoints. No differences in vitamin B3 were observed after and before FA intervention. Among kynurenine pathway metabolites, anthranilic acid was increased after 45 and 90 days, while picolinic acid was decreased after 90 days. hs-CPR, serum IL-6, IL-8, IL-10, IFN-γ and TNF-α were similar at baseline and after intervention. An increase on mRNA expression of DHFR and TNFA was observed after, respectively, 90 days and 45 and 90 days of intervention. After 90 days of FA intervention, it was observed a decrease on Treg cell number after PMA and ionomycin stimulation. Conclusion: Daily use of 5 mg of FA was associated with changes in serum markers of B-complex vitamins status and kynurenine pathway, as well as decreased number of Treg cells

Neopterin Levels and Indoleamine 2,3-Dioxygenase Activity as Biomarkers of Immune System Activation and Childhood Allergic Diseases

BACKGROUND: Although Th2 immune activation is predominant in allergic diseases, neopterinlevels and indoleamine 2,3-dioxygenase (IDO)-1 activity (kynurenine:tryptophan ratio), which reflect Th1 immune activity, increase with interferon-gamma (IFN-γ) stimulation. We investigated neopterin, tryptophan, and kynurenine levels as biomarkersof the Th1 immune system activation and changes in IDO-1 activityin children with asthma, allergic rhinitis, and atopic dermatitis, as well as the relationship between these biomarkers and the total IgE level, age, and disease severity. METHODS: We divided 205 children (80 girls and 125 boys, four months to 17 years old) into four groups: controls, patients with asthma, patients with allergic rhinitis, and patients with atopic dermatitis. Peripheral venous blood samples were collected. Neopterin levels were determined by an enzyme immunoassay. Tryptophan and kynurenine levels were analyzed using HPLC. IDO-1 enzyme activity was calculated using tryptophan and kynurenine levels. IgE levels were measured. The Mann-Whitney U test, Kruskal-Wallis test, and Conover post-hoc method were used for statistical analysis. RESULTS: Neopterin, tryptophan, and kynurenine levels were higher and IgE levels and IDO-1 enzyme activity were lower in patients with asthma and allergic rhinitis than in controls (P < 0.05). Patients with atopic dermatitis showed higher neopterin, tryptophan, and kynurenine levels, higher IDO-1 activity, and lower IgE levels thancontrols (P < 0.05). CONCLUSIONS: The Th1/Th2 balance is disrupted in children with allergic diseases, concomitant with increased Th1-mediated immune response activation and reduced IgEproduction, which is promoted by Th2-type cytokines.

Regulation of Chaihu Shugan Powder on kynurenine in raphe nucleus of depressive rats induced by reserpine / 中华行为医学与脑科学杂志

Objective To investigate the antidepressant effects of Chaihu Shugan Powder(CSP) on depressive rats induced by reserpine and its influences on the kynurenine (KYN),indoleamine 2,3-dioxyge-nase(IDO),interleukin-6(IL-6) and tumor necrosis factor-α( TNF-α). Methods Forty rats with similar behavior results were divide into 4 groups randomly,including Control group(Con),Model group(Res),Flu- oxetine group(Res+Flu) and Chaihu Shugan Powder group(CSP). The depressive rat model was established by intraperitoneal injection reserpine. The rats in Res+Flu group were administered with fluoxetine by intrap-eritoneal and rats in Res+CSP group were administered with CSP by intraperitoneal. After 14 days,the be-havior of rats was measured and then the rats were executed and sampled. The content of tryptophan and kynurenine in raphe nuclei tissue were detected. The mRNA expression level of IDO,IL-6,TNF-α in raphe nuclei tissue were detected. Results ( 1) Compared with Con group (( 81. 81 ± 36. 13) s, ( 83. 51 ± 5. 34)%), the swimming immobility time((150. 50±31. 45)s) in Res group increased(t=68. 7, P<0. 05) and the sucrose perference (59. 73±11. 30)%) in Res group decreased(t=23. 8,P<0. 05). Compared with Res group, the swimming immobility time in Res+Flu group((114. 90± 14. 29) s) and Res+CSP group ((111. 7±11. 34)s) decreased(t=35. 6,35. 8,both P<0. 05). Compared with Res group, the sucrose pref-erence in Res+Flu group((78. 21±10. 07)%) increased(t=18. 3, P<0. 05). (2)Compared with Con group (KYN/TRP:(0. 023±0. 016),IDO mRNA:(1. 00±0. 05),IL-6 mRNA:(1. 00±0. 58),TNF-α mRNA:(1. 00±0. 32)), the activity of IDO(KYN/TRP(0. 039±0. 003)) and the mRNA levels of IDO mRNA(3. 63± 0. 31),IL-6 mRNA(2. 36±0. 23),TNF-α mRNA( 3. 56± 0. 14) of Raphe Nuclei tissue in Res group were significantly increased (t=21. 2,12. 9,38. 3,19. 7,all P<0. 05). Compared with Res group, the activity of IDO(KYN/TRP(0. 030±0. 013)),the mRNA expression levels of IDO mRNA( 1. 56±0. 36),IL-6 mRNA (1. 62±0. 16),TNF-α mRNA(2. 64±0. 20)of Raphe Nuclei tissue in Res+Flu group were significantly de-creased(t=38. 8,15. 8,12. 8,26. 4,all P<0. 05). And compared with Res group,the activity of IDO( KYN/TRP(0. 028±0. 021)) ,the mRNA expression level of IDO mRNA( 1. 33± 0. 29),IL-6 mRNA(1. 36± 0. 34),TNF-α mRNA(1. 93±0. 21)of raphe nuclei tissue in Res+CSP group were also significantly decreased (t=23. 21,17. 3,19. 8,29. 8,all P<0. 05). Compared with Res+Flu group,the level of IDO mRNA and in-flammatory factors' mRNA in Res+CSP group were significantly decreased(t=18. 3,20. 8,31. 5,all P<0. 05). Conclusion Chaihu Shugan Powder has antidepressant effect,and the mechanism is related with de-creasing the inflammatory factors,inhibiting IDO activation and decreasing the IDO mRNA.

Advanced research of kynurenine pathway mechanism in suicide of major depressive disorder / 上海交通大学学报（医学版）

Major depressive disorder (MDD) is one of the world’s major chronic and disabling mental diseases. By 2030, MDD is expected to be the top of all the disease burden in the world, with high prevalence, high recurrence rate, high disability rate, and high suicide rate. Suicide is the most serious consequence of MDD. Current studies showed that inflammatory levels in the central nervous system and peripheral blood of patients with MDD were higher, and increased more significantly in depressive patients with suicidal ideation or behavior. Related researches showed that increased levels of inflammatory cytokines were associated with dysregulation of kynurenine metabolic pathway, leading to imbalances in neurometabolites, such as an excess of the neurotoxic product quinolinic acid and a decrease in the protective neuropeptide picolinic acid. This paper reviews kynurenine metabolic pathway, expecting to identify the biomarkers of MDD patients with suicide.

Quercetin inhibits proliferation of human cervical carcinoma HeLa cells through affecting tryptophan metabolism / 中国药理学通报

Aim To investigate the mechanism of inhibition on the proliferation of human cervical carcinoma HeLa cells by quercetin.Methods Cell proliferation was detected by CCK-8 method.Flow cytometry was used to detect the cell cycle changes.OD480 values which reflected the metabolism of tryptophan and the production of kynurenine were measured by UV-Vis spectrophotometer.The mRNA levels of IDO1 were detected by qPCR.The expression and purification of IDO1 protein were detected by Western blot.Enzyme activity reaction was performed in vitro,and the content changes of tryptophan and kynurenine were detected by HPLC.Results Quercetin inhibited the proliferation of HeLa cells and led to cell cycle arrest.Quercetin inhibited the metabolism of tryptophan.Quercetin significantly inhibited the enzymatic activity of IDO1 in vitro,but did not affect the expression of IDO1.The addition of kynurenine could reverse the inhibition of cell proliferation induced by quercetin.Conclusion Quercetin affects tryptophan metabolism through inhibiting the enzymatic activity of IDO1.This may be one of the mechanisms by which quercetin exerts its effect on the proliferation of HeLa cells.

Advance of the role of Aromatic hydrocarbon receptor in immunoregulation related to tryptophan metabolism / 国际外科学杂志

Aromatic hydrocarbon receptor (AhR),an intracellular receptor,contains multiple ligand binding sites.Various ligands of AhR are divided into exogenous and endogenous ligands according to the origination.Different ligands bind and activate AhR,regulating the transcription of downstream target genes,especially CYP1 from Cypcytochrome P450 gene family,which plays an essential role in different pathological problems,as well as in the normal development and function of organism.Kynurenine(Kyn),a key metabolic product of tryptophan (Trp),metabolic products of which are major types of endogenous ligands of AhR,has an impact on adaptive immune by manipulating the polarization and activity of immunocytes.Kyn has been focus for its supressive effect in anti-tumor immunity and raised concern recently for its intriguing role in allograft immunoregulation.Research advances in the role of AhR in immunoregulation related to tryptophan metabolism will be illustrated in this review in detail.

Clinical Significance of Serum Kynurenine and Uric Acid Levels Detection in Chronic Myeloid Leukemia Patients / 现代检验医学杂志

Objective To investigate the clinical significance of kynurenine (KYN) and uric acid (UA) levels in chronic myeloid leukemia patients (CML).Methods 30 CML patients (CML group) and 25 healthy controls (Control group) were enrolled in the hospital from Mar 2014 to Dec 2015.Serum KYN and tryptophan (TRP) of all subjects were determined by high performance liquid chromatography,and KYN/TRP ratio (KTI) were calculated.Leukocytes were counted by automat ic blood cell analyzer.Serum UA were detected by enzyme method.Correlation between UA and KTI,leukocytes were analyzed by Pearson correlation.Results The serum KTI of the CML group (49.76±19.06) before treatment was significantly higher than that of the control group (27.87-±-5.06,t=4.470,P=0.001).KTI cutoff value was 40 by ROC analysis.There had correlation between KTI and leukocytes (r=0.743,P=0.001) and no correlation between KTI and ages (r=0.205,P =0.276).KTI (64.7±17.8) and the leukocytes [(96.7±64.1) × 109/L] of 10 cases of KTI≥40 of CML patients before treatment was significantly higher than that of KTI (27.0± 10.9,t=7.102,P =0.001) and the leukocytes[(10.1 ± 5.2) × 109/L,t=4.285,P=0.002] after treatment.The serum UA in KTI＜40 CML patients (n=15,354.98±103.9 μmol/L) was significantly lower than that of KTI≥40 CML group CML (n=15,484.98±132.1 μmol/L,t=1.432,P=0.045).The UA in CML group was associated with KTI (r=0.573,P=0.001) and leukocytes (r=0.537,P=0.002).Conclusion The increase of KTI in CML patients suggested that an increased activity of indoleamine-2,3-dioxygenase (IDO).IDO activity may associated with CML morbidity and therapy effect.The detection of KTI may contribute to the diagnosis of CML and assessing therapy effect of CML.

Tryptophan metabolism change in patients with chronic hepatitis B and hepatitis B cirrhosis and its correlation analysis / 重庆医学

Objective To investigate the tryptophan (Trp) metabolism change in the patients with chronic hepatitis B (CHB) and hepatitis B cirrhosis (HBC) and to analyze the related risk .Methods Eighty-one cases of CHB and 40 cases of HBC hospitalized in the First Affiliated Hospital of Chongqing Medical University from October 2015 to January 2016 served as the stud-y subjects ,and 40 healthy persons as the controls .High performance liquid chromatography -fluorescence detection (HPLC-FD) were adopted to detect the levels of plasma Trp ,kynurenine (Kyp) and its metabolite 5-hydroxy tryptamine (5-HT) .HBV-DNA vi-ral replication number was detected by real-time quantitative PCR .The serological indicators differences among 3 groups were ana-lyzed .The risk factors were analyzed and screened by the Logistic regression analysis and Pearson correlation analysis .Results Compared with the control group ,plasma 5-HT and Trp levels in the CHB group and HBC group were significantly decreased (P<0 .01);plasma Kyn/Trp in the HBC group was significantly higher than that in the other two groups (P<0 .01) .Kyn/Trp in the HBC group was negatively correlated with A/G (r= -0 .686 ,P<0 .01) ,and Kyn/Trp in the CHB group was positively correlated with Log DNA (r= 0 .784 ,P<0 .01) .The Logistic regression analysis indicated that Kyn/Trp was the risk factor of CHB and HBC .Conclusion Detecting plasma Trp and its metabolite can serve as the adjuvant indicators for assessing the progression of hep-atitis B .

High-Fat Diet and Voluntary Chronic Aerobic Exercise Recover Altered Levels of Aging-Related Tryptophan Metabolites along the Kynurenine Pathway

Tryptophan metabolites regulate a variety of physiological processes, and their downstream metabolites enter the kynurenine pathway. Age-related changes of metabolites and activities of associated enzymes in this pathway are suggestable and would be potential intervention targets. Blood levels of serum tryptophan metabolites in C57BL/6 mice of different ages, ranging from 6 weeks to 10 months, were assessed using high-performance liquid chromatography, and the enzyme activities for each metabolic step were estimated using the ratio of appropriate metabolite levels. Mice were subjected to voluntary chronic aerobic exercise or high-fat diet to assess their ability to rescue age-related alterations in the kynurenine pathway. The ratio of serum kynurenic acid (KYNA) to 3-hydroxylkynurenine (3-HK) decreased with advancing age. Voluntary chronic aerobic exercise and high-fat diet rescued the decreased KYNA/3-HK ratio in the 6-month-old and 8-month-old mice groups. Tryptophan metabolites and their associated enzyme activities were significantly altered during aging, and the KYNA/3-HK ratio was a meaningful indicator of aging. Exercise and high-fat diet could potentially recover the reduction of the KYNA/3-HK ratio in the elderly.

Simultaneous determination of L-tryptophan and L-kynurenine in rat plasma by LC-MS/MS / 中国药科大学学报

@#To establish a simple and sensitive LC-MS/MS method for simultaneous determination of the concentration for L-tryptophan(L-Try)and L-kynurenine(L-Kyn)in rat plasma. The changesin the process of the liver tumors formation may provide a basis for the diagnosis of liver cancer. 3-Nitro-L-tyrosine(3-NT)were added as the internal standard for the determination of two active substances and the chromatographic analysis was performed on a RRHD Eclipse Plus C18 column(3. 0 mm×100 mm, 1. 8 μm). The mobile phase was composed of water and acetonitrile(containing 0. 1%formic acid)(90 ∶10)at a flow rate of 0. 25 mL/min, and the injection volume is 5 μL. Detection and quantification were performed by mass spectrometry in multiple reaction monitoring mode with m/z 205. 12→146. 10(L-Try), m/z 209. 09 →146. 10(L-Kyn), m/z 227. 09→181. 10(3-NT), respectively. The results show that thelinear ranges were 9. 670-9 670 ng/mL for L-Try, and 9. 973-9973 ng/mL for L-Kyn(r2≥0. 9990). The limit of quantitation were 9. 670 ng/mL for L-Try, and 9. 973 ng/mL for L-Kyn, respectively. The intra- and inter-day precisions were all less than15%; the recoveries ofthe two analytes were more than 81. 17% and severe matrix effect was not observed. The ratio of L-Try/L-Kyn determined by LC-MS/MS in rat plasma showed an overall downward trend, which could used effectively for the drug metabolism studies and researches on the action mechanism of medicine on liver cancer. A rapid, simple, sensitive and specific LC-MS/MS method has been successfully developed and could also be used effectively for the drug metabolism studies and researches on the action mechanism of medicine on liver cancer.

Effects of lipopolysaccharide on the tryptophan-kynurenine metabolic pathway / 中华行为医学与脑科学杂志

Objective To investigate the effects of lipopolysaccharide(LPS) on the tryptophan-kynurenine(TRP) metabolic pathway in rat brains and provide new evidence for the relationship between inflammation and depression.Methods Rats in LPS group were given a single dose of 3.5 mg/kg LPS.while the rats in control group were given the same dosage of saline.The dialysis in ventro-hippocampus were collected by microdialysis within 8 hours and then the TRP,KYN and KA were detected by LC-MS/MS.And the expression of indoleamine 2,3-dioxygenase was detected by Western-blot.Results The level of TRP((550.15± 107.96) pmol/L) and KYN ((337.95±62.73) pmol/L) showed a time-dependent increase after administration LPS 4 h compared with the control group(TRP (368.38±59.31) pmol/L,KYN (172.80±43.96) pmol/L),while KA level in the circulation exhibited a trend to decrease,especially at 7 h ((3.47±0.62) pmol/L,P＜0.05).The ratio of KYN/TRP significantly increased at about 5 h (0.69±0.11,P＜ 0.05),and an ratio of KA/KYN (0.02±0.00) was dramatically decreased after administering LPS 4 h compared with the control group (0.05±0.01)(P＜0.05).Most of the analytes showed more dramatic changes around 4 h to 8 h.LPS group(1.48±0.37) increased the protein expression of indoleamine 2,3-dioxygenase compared with the control group(1.00±0.24) (P＜0.01).Conclusions LPS may cause tryptophan metabolic abnormalities and accelerate the way of kynurenine metabolism,leading to decreased the kynurenic acid status.

Effect of replication-defective herpes simplex virus mediated kynurenine aminotransferase on detrusor overactivity in rats with spinal cord injury / 中华泌尿外科杂志

Objective To evaluate if replication-defective herpes simplex virus mediated kynurenine aminotransferase Ⅱ (HSV-KAT Ⅱ) could inhibit detrusor overactivity (DO) in rats with spinal cord injury by bladder wall injection.Methods From June 2012 to July 2013,48 male Wistar rats with T10 spinal cord transection (SCT) were randomly divided into normal saline group,HSV group and HSV-KAT Ⅱ group (n=16 each group).Normal saline (40 μl),HSV or HSV-KAT Ⅱ (40 μl,1×107 plaque forming unit viruses) was injected into the rat bladder wall of according group by 1 week after SCT.Three weeks after injection,cystometry was performed and the virus transfected efficiency,expression of KAT Ⅱ in L6-S1 dorsal root ganglia were examined.Results The DO number,DO amplitude,maximum voiding pressure and volume inducing voiding were decreased significantly by 59.6％-61.1％,21.6％-24.2％,30.3％-34.4％ and 44.1％-46.5％ (P＜0.01),while voiding efficiency,the time to first DO were increased significantly by 40.7％-47.7％ and 30.1％-49.0％ (P＜0.01) in the HSV-KAT Ⅱ group compared with normal saline group and HSV group.However,the leaking volumes were no significantly different among the 3 groups (P＞0.05).The relative intensity of KAT Ⅱ protein (0.50±0.13 versus 0.28±0.07,P＜0.05) and mRNA (0.78±0.06 versus 0.51±0.08,P＜0.01) were increased significantly in HSV-KAT Ⅱ group than those in HSV group.Conclusion HSV-KATⅡ bladder wall injection inhibits DO and may improve detrusor-sphincter dyssynergia in rats with spinal cord injury.

Clinical value of determination of serum IDO and KYN in ulcerative colitis / 安徽医科大学学报

Objective Detecting the level of IDO and KYN in ulcerative colitis (UC) patients; using ROC curve to discuss their value in the diagnosis of patients with active UC. Methods 60 cases of UC group, 18 cases of dis-ease control group and 20 cases of healthy control group were included in the study. Immunohistochemical staining methods were used to detect the expression of IDO in colonic mucosa of UC, enzyme-linked immunosorbent (ELISA) methods were used to detect the serum levels of IDO, KYN and CRP, and the value with ROC curve method was analyzed. Results ① There was a positive correlation between IDO level and IDO expression (P<0.05). There was a positive correlation between KYN level and IDO expression (P<0.05). ②The levels of IDO and KYN in UC group were higher than those of disease control group and health control group (P<0.05). ③The levels of IDO and KYN in patients with active UC were significantly higher than that in patients with catabasis UC (P<0.01), and the levels increased with severity of inflammation. ④ The levels of IDO and KYN in active UC were positively related to disease activity and CRP levels (P<0.05). ⑤The IDO,KYN and CRP area under ROC curve were 0.976, 0.856 and 0.864;best cut-off point were 53.66 U/L, 2.34 nmol/L and 1.75 mg/ml;sensitiv-ity were 90.5%, 78.65% and 100.0%; specifity were 94.4%, 83.3% and 61.1%; Youden index were 0.839 2, 0.619 0 and 0.611 1. Conclusion The levels of IDO and KYN in serum can be used as an important index to judge the severity of UC. They have important value in the diagnosis of active UC . The value of IDO is higher than KYN and CRP.

Simultaneous determination of tryptophan and kynurenine in plasma by HPLC with UV detection / 中华检验医学杂志

ObjectiveTo establish an accurate method for simultaneous determination of plasma Kyn and Trp by HPLC-UV detection.Methods Kyn and Trp were separated on Agilent Hypersil ODS column using 3-nitrotyrosine as internal standard.The mobile phase consisted of 15 mmol/L sodium acetateacetic acid (pH 5.5):acetonitrile 94∶ 6(v/v) at a rate of 0.8 ml/min.The chromatographic separation was performed at 25 ℃.The eluate was monitored with programmed wavelength setting at 360 nm from 0 to 4 min for Kyn and at 302 nm from 4 to 5 min for Trp.The method was applied to determination of plasma Kyn and Trp in 8 chronic glomerulonephritis,10 idiopathic thrombocytopenic purpura,15 chronic hepatitis B virus patients and 15 healthy controls from September to December in 2010.The differences were compared using ANOVA and SNK methods.Results The retention time of Kyn and Trp were 2.9 min and 4.4 min,respectively.For Kyn,the assay was linear from 0.44 μmol/L to 18.30 μmol/L.For Trp,the linearity was from 3.67 μmol/L to 470.00 μmol/L.The detection limits were 0.014 μmol/L for Kyn and 0.122 μmol/L for Trp,respectively.The within-day CVs were ＜ 3％ and the between-day CVs were ＜ 4％.The mean recoveries yield were in the range of 92.29 to 104.40.The plasma concentrations of Kyn were ( 1.59 ± 0.28),(2.73 ± 0.56),(2.69 ± 0.44) and ( 1.54 ± 0.48 ) μmol/L,the plasma concentrations of Trp were (59.8 ± 10.0),(46.1 ± 11.7),(58.5 ±8.0) and (41.4±13.1) μmol/L,the Kyn/Trp were (0.027 4±0.007 5),(0.061 6 ±0.016 5),(0.046 7 ±0.009 1) and (0.038 3 ±0.007 5)in controls,chronic glomerulonephritis patients,idiopathic thrombocytopenic purpura patients and chronic hepatitis B virus patients,respectively.There were significance difference of Kyn,Trp and Kyn/Trp amony the four groups (F=23.734,8.463,20.921,all P＜0.01).Conclusion The method is simple,fast,and suitable for applicability to clinical measurement.