Changes in serum indoleamine 2, 3-dioxygenase and kynurenic acid levels in preterm infants with bronchopulmonary dysplasia / 中华围产医学杂志

Objective:To explore the changes in serum indoleamine 2, 3-dioxygenase (IDO) and kynurenic acid (KYNA) levels in preterm infants diagnosed with bronchopulmonary dysplasia (BPD).Methods:A nested case-control study was conducted. The inclusion criteria covered premature infants with less than 32 weeks of gestational age within 24 h post-birth, from December 1, 2021, to December 31, 2022, at Children's Hospital of Soochow University. Those diagnosed with BPD were allocated to the BPD group ( n=35). Non-BPD preterm infants matching the BPD cases in terms of gestational age (within one week difference) and birth weight (within a 150 g difference) were selected in a 1∶1 ratio for the control group ( n=35). Serum levels of IDO and KYNA were measured on days 1, 7, 14, and 28 postnatally. Differences in serum IDO and KYNA levels were analyzed between the BPD and control groups and among infants with mild BPD versus moderate-to-severe BPD. The association between serum IDO and KYNA levels with the severity of BPD was also assessed. Statistical analysis was conducted using independent samples t-tests and Spearman's correlation analysis. Results:Elevated levels of serum IDO on days 7, 14, and 28 postnatally [(60.68±9.37) vs. (50.66±10.46), (57.81±11.07) vs. (44.45±8.20), and (50.62±10.77) vs. (41.31±7.74) pg/ml; t=4.21, 5.73, and 4.15, respectively] as well as increased serum KYNA levels on days 14 and 28 [(439.31±41.22) vs. (368.99±68.79), (376.97±45.74) vs. (325.50±60.07) μmol/L; t=5.18 and 4.03, respectively] were observed in the BPD group compared to the control group, with all differences being statistically significant (all P<0.05). Furthermore, positive correlations were observed between serum IDO levels and BPD severity on the 7th, 14th, and 28th days ( r=0.546, 0.495, and 0.502, all P<0.05), as well as between serum KYNA levels and BPD severity on the 14th and 28th days ( r=0.536 and 0.458, both P<0.05). Conclusion:Elevated serum levels of IDO and KYNA in infants with BPD suggest these metabolites may play a role in the pathogenesis and progression of BPD.

Relationship between metabolites of peripheral tryptophan-kynurenine metabolic pathway and clinical symptoms in patients with schizophrenia / 四川精神卫生

BackgroundSchizophrenia is a common severe mental disorder with complex pathogenesis. There are few studies on the correlation between kynurenine metabolites in peripheral serum and urine in schizophrenia. ObjectiveTo investigate the concentration of tryptophan-kynurenine metabolites and interleukin-6 （IL-6） in serum and urine in patients with schizophrenia， and their correlation with clinical symptoms， so as to explore potential biological characteristics related to schizophrenia. MethodsA total of 38 patients with schizophrenia who met the criteria of the Diagnostic and Statistical Manual of Mental Disorders， fifth edition （DSM-5）， and were hospitalized or attended outpatient clinic at Hangzhou Seventh People's Hospital from December 2021 to December 2022 were included in the study. Additionally， 26 healthy individuals were concurrently recruited from the community of Hangzhou to serve as a control group. All participants were requested to complete the Positive and Negative Symptom Scale （PANSS）. The levels of tryptophan （TRP）， kynurenine （KYN）， kynurenic acid （KYNA）， quinolinic acid （QUIN）， picolinic acid （PIC）， xanthurenate and 5-hydroxytryptamine （5-HT） in both serum and urine were measured using ultra-high-performance liquid chromatography-triple quadrupole linear ion trap mass spectrometry. Serum and urine IL-6 were measured using enzyme-linked immunosorbent assay. Pearson correlation analysis was conducted to examine the correlation between serum and urinary KYN metabolites， as well as the correlation between metabolite levels and clinical symptoms in the patient group. ResultsPatients with schizophrenia had significantly higher level of IL-6 in serum （U=798.500， P<0.01） and lower level of PIC in urine （U=253.000， P=0.013） compared with the control group. Additionally， level of serum KYN was positively correlated with QUIN/KYNA ratio and QUIN/PIC ratio （r=0.562， 0.438， P<0.05） in patients with schizophrenia. 5-HT/KYN ratio in serum was positively correlated with PANSS total score and negative symptom subscale score （r=0.458， 0.455， P<0.01） in patients with schizophrenia. ConclusionSerum TRP-KYN pathway metabolite levels in patients with schizophrenia were associated with neurotoxic metabolite ratios in urine and the severity of negative symptoms. ［Funded by Zhejiang Medical and Health Science and Technology Program Exploratory （number， 2022KY990）］

Research progress on the influence of ligands on the stability of albumin / 中国输血杂志

It is necessary to improve the stability of human serum albumin in response to the complex temperature, light and other conditions during the manufacture and storage. In this paper, the stabilization effect and simple stabilization mechanism of ligands on albumin were described from the perspective of ligand binding to albumin.Through review and comparison, it can be concluded that the common ligand sodium octanoate mainly plays a role in improving thermal stability, and the common ligand N-acetyl-L-tryptophan mainly plays a role in improving antioxidant activity, N-acetyl-L-methionine has better antioxidant and anti-photooxidation than N-acetyl-L-tryptophan.

The Associations of Serum Tryptophan and Tyrosine With Alzheimer’s Disease / 生物化学与生物物理进展

ObjectiveA growing body of research suggests a strong link between metabolic imbalance and Alzheimer’s disease (AD). In recent years, the development of metabolomics makes it possible to study the characteristic changes of peripheral metabolism in AD. Serum levels of tryptophan and tyrosine were associated with mild cognitive impairment (MCI) and AD. The purpose of this study is to further characterize tryptophan and tyrosine levels in MCI and AD. MethodsWe stratified 765 participants from the Alzheimer’s Disease Neuroimaging Initiative-1 (ADNI-1) cohort into cognitively normal (CN; n=207), stable mild cognitive impairment (sMCI; n=201), progressive mild cognitive impairment (pMCI; n=171), and dementia due to AD (n=186). Serum tryptophan and tyrosine were analyzed for diagnostic value of MCI and AD. To evaluate the relationships between serum tryptophan and tyrosine and cerebrospinal fluid (CSF) biomarkers, brain structure (magnetic resonance imaging, MRI), cerebral glucose metabolism (18F-fluorodeoxyglucose-positron emission tomography, FDG-PET), and cognitive declines, through different cognitive subgroups. ResultsSerum tryptophan was decreased in patients with AD, pMCI or sMCI compared with CN. Serum tyrosine was decreased in patients with AD or pMCI compared with CN. Serum tryptophan has diagnostic value for pMCI and AD. Serum tyrosine has diagnostic value for AD. ConclusionSerum tryptophan and tyrosine contribute to the early diagnosis of AD. The detection of tryptophan and tyrosine can contribute to the pathogenesis of AD. Serum tryptophan and tyrosine were not significantly associated with core AD markers, cognitive function, brain structure and brain metabolism, so serum tryptophan and tyrosine may not be good peripheral AD biomarkers.

Can supplementation of tryptophan in parenteral nutrition increase melatonin and alleviate inflammatory response?

SUMMARY OBJECTIVE: Endogenous melatonin is produced from tryptophan which is an essential amino acid. Besides its role in the regulation of sleep patterns, melatonin has anti-inflammatory effects. In this case-control study, we aimed to compare tryptophan and melatonin levels and their relationship with the inflammatory response, specifically serum interleukin-1, interleukin-6, and c-reactive protein levels following major abdominal surgery in patients with food restriction and who receive parenteral nutritional therapy. METHODS: We enrolled 40 patients between the ages of 18 and 65 years in the study. We collected blood and urine samples 48 h before the operation and on postoperative days 1, 3, and 5. RESULTS AND CONCLUSION: The tryptophan levels in the experimental group were higher than in the control group but failed to reach any statistical difference. Melatonin levels were increased in both groups following the surgery compared with preoperative levels. The increase in the experimental group was statistically different 3 days after the surgery. The difference in the level of interleukin-1 between the control and the experimental groups was greatest on postoperative day 3. On postoperative day 3, the interleukin-6 level in the treatment group was slightly higher than in the control group. We did not find any difference in the levels of c-reactive protein between the groups. As a result, the levels of tryptophan and melatonin were increased in the parenteral nutrition group, irrespective of the postoperative inflammatory response.

Análise do transcriptoma de diferentes tipos de células únicas do sangue periférico de pacientes infectados com o vírus da Dengue para detalhamento da massiva geração de células secretoras de anticorpos / Evaluation of the tryptophan metabolism in the massive generation of antibody-secreting cells in Dengue patients through the transcriptome of single blood cells

A Dengue induz uma resposta exacerbada e transitória das células secretoras de anticorpos (ASCs) no sangue de pacientes cerca de sete dias após o início dos sintomas. A frequência dessas ASCs chega a representar mais de 50% de todas as células B circulantes neste período. No entanto, ainda é desconhecido se a magnitude dessa resposta tem relação com a gravidade da Dengue. Nosso grupo de pesquisa já mostrou que a cultura de células nucleares do sangue periférico (PBMCs) de indivíduos saudáveis com partículas do vírus da Dengue (DENV), por 7 dias, levava a diferenciação de células B em ASCs em magnitude similar àquelas estimuladas por mitógenos. Essas culturas apresentavam um consumo significativamente maior de triptofano (TRP), associado à maior expressão das enzimas IDO1 e IDO2, e, consequentemente, maior síntese de quinurenina (KYN) em relação ao estímulo por mitógenos. Considerando que as concentrações de TRP e KYN detectadas nos sobrenadantes dessas culturas eram diretamente proporcionais ao aumento de ASCs, decidimos investigar o papel desse metabolismo do TRP e de seus respectivos metabólitos na diferenciação das ASCs. Para isso, análises do transcriptoma público de células únicas do sangue periférico de pacientes com Dengue (estudo E-MTAB- 9467) foram realizadas para inferir a real participação do metabolismo do TRP na geração de ASCs. Com o programa R foram executadas análises de Downstream. Identificamos um aumento massivo das ASCs nas amostras dos pacientes infectados com Dengue. No entanto, os principais genes desencadeadores da ativação do metabolismo do TRP (IDO1 e IDO2) não foram expressos nas subpopulações de células B, mas sim em células dendríticas e monócitos CD14+ respectivamente. Isso sugeriria que esta via não seria ativada nos linfócitos B. Por outro lado, genes codificadores de outros participantes da via do TRP (HSD17B10, ECHS1 e SIRT3) foram detectados em células B e podem estar relacionados com a proliferação das ASCs. Além disso, a análise de enriquecimento mostrou uma aumentada expressão de genes associados com moléculas de MHC de classe II em plasmablastos e plasmócitos de pacientes com Dengue. Porém, com a expressão aumentada de ENTPD1 nessas células durante a fase sintomatológica, nossos dados sugerem também que um eventual papel de plasmablastos e plasmócitos como apresentadoras de antígenos na Dengue poderia induzir uma resposta supressora de células T

Dengue can cause an exacerbated and transient antibody-secreting cell (ASC) response in the blood of patients nearly 7 days of symptomatology. The ASC frequency reaches more than 50% of all circulating B cells during that period. However, it is still unknown whether the magnitude of this response may be directly related to the severity of Dengue. Our research group has already shown that the culture of peripheral blood mononuclear cells (PBMCs) from healthy individuals with Dengue virus (DENV) particles for 7 days led to a differentiation of B cells into ASCs to a magnitude similar to those stimulated by mitogens. These cultures showed significantly higher consumption of tryptophan (TRP), associated with higher expression of enzymes IDO1 and IDO2, and consequently, higher synthesis of quinurenine (KYN) compared to mitogen stimulation. The concentrations of TRP and KYN detected in the supernatants of these cultures were directly proportional to ASC frequency increase. Thus, we have decided to investigate the role of TRP metabolism and its respective metabolites in ASC differentiation. For this, we performed an analysis of single-cell transcriptome with peripheral blood from Dengue patients (dataset from E-MTAB-9467 study). Downstream analyses were performed with R software. Corroborating with literature, we identified a massive increase in ASC frequency of Dengue infected patients. However, the main genes triggering TRP metabolism activation (IDO1 and IDO2) were not expressed in B-cell subsets, but in dendritic cells and CD14+ monocytes, respectively. This would suggest that this pathway would not be activated in B lymphocytes. Nevertheless, genes encoding other participants in the TRP pathway (HSD17B10, ECHS1, and SIRT3) were detected in B cells and may be related to ASC proliferation. Futhermore, a Gene Ontology analysis showed an increased expression of genes associated with MHC class II molecules in plasmablasts and plasma cells of Dengue patients. As these cells also presented an increased expression of ENTPD1 during the symptomatic phase, our data suggest a potential role of plasmablasts and plasma cells as antigen-presenting cells associated with a suppressive T cell response in Dengue

Confirmación de la presencia de células serotoninérgicas en la corteza cerebral fetal en cultivos e in situ / Confirmation of the presence of serotonergic cells in the fetal cerebral cortex in cultures and in situ

Resumen Antecedentes: La aparición temprana de serotonina en el cerebro fetal y sus efectos en la morfogénesis cerebral apoyan su papel neurotrófico. Objetivo: Determinar la presencia de células serotoninérgicas y la expresión de triptófano-5-hidroxilasa (TPH), 5-hidroxitriptamina (5-HT), transportador de serotonina (SERT), receptor 5-HT1A y Pet-1 durante el desarrollo de la corteza cerebral, tanto in situ como en cultivo de tejidos. Material y métodos: Se realizó estudio observacional descriptivo en ratas Wistar preñadas. La presencia del tapón se consideró el inicio de la gestación; en los días 13, 16 y 17 se practicaron cesáreas para obtener los fetos e inmediatamente se disecaron los cerebros para identificar células serotoninérgicas, TPH, 5-HT, SERT, 5-HT1A y Pet-1 en cultivo de tejido e in situ mediante inmunomarcaje detectado en un microscopio confocal. Resultados: Células y terminales serotoninérgicas fueron observadas en el mesencéfalo el día 17 de gestación y en cocultivos de neopalio los días 13 y 16. También se observaron células inmunopositivas a TPH, 5-HT, SERT y Pet-1 en el neopalio en el día 12 del cultivo. Conclusiones: Se confirmó la presencia de células serotoninérgicas y otros elementos del sistema serotoninérgico en la corteza cerebral temprana, la cual puede ser transitoria y participar en los procesos de maduración cortical durante el desarrollo cerebral.

Abstract Background: Early appearance of serotonin in the fetal brain and its effects on brain morphogenesis support its neurotrophic role. Objective: To determine the presence of serotonergic cells and the expression of tryptophan-5-hydroxylase (TPH), 5-hydroxytryptamine (5-HT), serotonin transporter (SERT), 5-HT1A receptor and Pet-1 during the development of the cerebral cortex, both in situ and in tissue cultures. Material and methods: A descriptive, observational study was carried out in pregnant Wistar rats. The presence of the plug was regarded as the beginning of gestation. On days 13, 16 and 17, cesarean sections were performed to obtain the fetuses, and the brains were then immediately dissected to identify the presence of serotonergic cells, TPH, 5-HT, SERT, 5-HT1A and Pet-1 in tissue cultures and in situ by immunostaining detected on a confocal microscope. Results: Serotonergic cells and terminals were observed in the midbrain on day 17 of gestation, and in neopallium cocultures on days 13 and 16. TPH, 5-HT, SERT and Pet-1 immunopositive cells were also observed in the neopallium on day 12 of culture. Conclusions: The presence of serotonergic cells and other elements of the serotonergic system in the early cerebral cortex was confirmed, which may be transient and participate in cortical maturation processes during brain development.

The kynurenine pathway in major depressive disorder, bipolar disorder, and schizophrenia: a systematic review and meta-analysis of cerebrospinal fluid studies

Objectives: The kynurenine (KYN) pathway has been attracting attention as a relevant pathway in schizophrenia (SZ), bipolar disorder (BD), and major depressive disorder (MDD). We conducted a systematic review and meta-analysis of studies examining KYN pathway metabolites from cerebrospinal fluid (CSF) samples in SZ, BD, and MDD. Methods: The PubMed and Scopus databases were systematically searched to identify peer-reviewed case-control studies published until April 2022 that assessed KYN metabolites, namely, tryptophan (TRP), KYN, kynurenic acid (KA), quinolinic acid (QA), and 3-hydroxykynurenine (3-HK), in subjects with SZ, BD, or MDD compared with healthy controls (HC). The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed. The random effects model method was selected for comparison of standardized mean differences (SMD) between two groups. Results: Twenty-three articles met the inclusion criteria (k = 8, k = 8, k = 11, for SZ, BD, and MDD, respectively). In SZ, KA levels were increased (SMD = 2.64, confidence interval [CI] = 1.16 to 4.13, p = 0.0005, I2 = 96%, k = 6, n=384). TRP (k = 5) and KYN (k = 4) did not differ significantly. In BD, TRP levels (k = 7) did not differ significantly. The level of KA was increased in MDD (k = 2), but the small number of studies precluded evaluation of statistical significance. Finally, in MDD, although some studies tended to show an increased level of KYN in those with remission vs. decreased levels in those with current depression, no significant difference was found in any KYN metabolite levels. Similarly, an increased level of QA was found, but the number of studies (k = 2) was small. Conclusion: KA, which has possibly neuroprotective effects, is increased in SZ. QA, which has neurotoxic effects, may be increased in MDD. There were no alterations in BD. Alterations in the KYN pathway may occur based on population characteristics and mood states. Future studies should explore the utility of these metabolites as biomarkers.

Modular engineering of Escherichia coli for high-level production of l-tryptophan / 生物工程学报

As an essential amino acid, l-tryptophan is widely used in food, feed and medicine sectors. Nowadays, microbial l-tryptophan production suffers from low productivity and yield. Here we construct a chassis E. coli TRP3 producing 11.80 g/L l-tryptophan, which was generated by knocking out the l-tryptophan operon repressor protein (trpR) and the l-tryptophan attenuator (trpL), and introducing the feedback-resistant mutant aroGfbr. On this basis, the l-tryptophan biosynthesis pathway was divided into three modules, including the central metabolic pathway module, the shikimic acid pathway to chorismate module and the chorismate to tryptophan module. Then we used promoter engineering approach to balance the three modules and obtained an engineered E. coli TRP9. After fed-batch cultures in a 5 L fermentor, tryptophan titer reached to 36.08 g/L, with a yield of 18.55%, which reached 81.7% of the maximum theoretical yield. The tryptophan producing strain with high yield laid a good foundation for large-scale production of tryptophan.

Mechanism of tryptanthrin in treatment of ulcerative colitis in mice based on serum metabolomics / 中国中药杂志

This study aims to explore the effect of tryptanthrin on potential metabolic biomarkers in the serum of mice with ulcerative colitis(UC) induced by dextran sulfate sodium(DSS) based on liquid chromatography-mass spectrometry(LC-MS) and predict the related metabolic pathways. C57BL/6 mice were randomly assigned into a tryptanthrin group, a sulfasalazine group, a control group, and a model group. The mouse model of UC was established by free drinking of 3% DSS solution for 11 days, and corresponding drugs were adminsitrated at the same time. The signs of mice were observed and the disease activity index(DAI) score was recorded from the first day. Colon tissue samples were collected after the experiment and observed by hematoxylin-eosin(HE) staining. The levels of interleukin-4(IL-4), interleukin-10(IL-10), tumor necrosis factor-α(TNF-α), interleukin-6(IL-6), and interleukin-8(IL-8) in the serum were measured by enzyme linked immunosorbent assay(ELISA). The serum samples were collected from 6 mice in each group for widely targeted metabolomics. The metabolic pathways were enriched by MetaboAnalyst 5.0. The results showed that compared with the model group, tryptanthrin treatment decreased the DAI score(P<0.05), alleviated the injury of the colon tissue and the infiltration of inflammatory cells, lowered the levels of proinflammatory cytokines, and elevated the levels of anti-inflammatory cytokines in the serum. The metabolomic analysis revealed 28 differential metabolites which were involved in 3 metabolic pathways including purine metabolism, arachidonic acid metabolism, and tryptophan metabolism. Tryptanthrin may restore the metabolism of the mice with UC induced by DSS to the normal level by regulating the purine metabolism, arachidonic acid metabolism, and tryptophan metabolism. This study employed metabolomics to analyze the mechanism of tryptanthrin in the treatment of UC, providing an experimental basis for the utilization and development of tryptanthrin.

Breastfeeding and infant sleep:a review / 中国实用护理杂志

Sufficient and organized sleep is a key factor during the developmental process of infancy while disrupted sleep schedule and diseases might lead to sleeping disorders in infants. Breastfeeding is considered to be the most beneficial way to meet the nutritional needs of infants for optimal growth and development. The α-lactalbumin-tryptophan-melatonin axis, nucleotides, and other factors are breast milk components that may affect infant sleep. Meanwhile, diet, feeding schedule, tobacco smoking, alcohol intake, and caffeine consumption will affect the circadian rhythms which might lead to the fluctuations of sleep-influencing factors in breast milk. This study reviews literature of previous studies on this topic to summarize information that can be considered for both breastfeeding practice and future basic research on the establishment of organized sleep patterns in infants.

Development and validation of ID-LC-MS/MS method for L-tryptophan and its metabolites / 中华检验医学杂志

Objective:To establish an isotope dilution liquid chromatography-tandem mass spectrometry (ID-LC-MS/MS) method for the determination of L-tryptophan and its metabolites in serum.Methods:The methodology was established and evaluated using serum samples collected from 166 healthy subjects undergoing physical examinations at West China Hospital from November 2022 to January 2023 were collected. Isotope-labeled markers of L-tryptophan (Trp), L-kynurenine (Kyn), and kynurenic acid (KA) were used as internal standards. After protein precipitation treatment of serum samples, LC-MS/MS was used to determine Trp, Kyn, and KA simultaneously. The selectivity, specificity, linearity, detection limit (LOD), quantification limit (LOQ), carry-over, precision, recovery rate, matrix effect, and dilution integrity of the method were evaluated.Results:The linearity of Trp, Kyn, and KA was demonstrated to be 0.999. The LODs were 0.10 μmol/L, 0.01 μmol/L and 1.00 nmol/L, respectively. The LOQs were 0.20 μmol/L, 0.04 μmol/L and 2.00 nmol/L, respectively. The intra-batch precision and inter-batch precision were below<10%. The average recovery rate and the relative matrix effect were all about 100%. The samples over the upper limit of quantitation can be diluted up to 16 times. The Trp concentration, Kyn concentration, KA concentration, Kyn/Trp ratio, and KA/Kyn ratio in serum of healthy subjects were 59.55±10.92 μmol/L, 1.85±0.43 μmol/L, 39.89±17.93 nmol/L, (31.64±8.19)×10 -3 and 21.51±6.72, respectively. Conclusion:An ID-LC-MS/MS method was successfully established for the quantitative determination of Trp, Kyn, and KA in serum. The method proved to be simple, rapid, sensitive, accurate, and reliable, providing robust support for clinical research related to these analytes.

Effects of moxibustion on behaviors and tryptophan metabolism-related products in mice with irritable bowel syndrome / 针灸推拿医学（英文版）

Objective: To observe the effect of moxibustion on behaviors and related products of tryptophan (Trp) metabolism in the colon of mice with irritable bowel syndrome (IBS), and to explore the mechanism of moxibustion in the IBS treatment.Methods: Twenty-four mice were randomly divided into a normal group, a model group, a moxibustion group, and a probiotic group, with 6 mice in each group. The visceral pain model of IBS was established by enema with 2,4,6-trinitrobenzene sulfonic acid (TNBS) solution. Mice in the moxibustion group were treated with mild moxibustion at bilateral Zusanli (ST36), and those in the probiotic group were treated with probiotics such as Bifidobacterium by gavage. Abdominal withdrawal reflex (AWR) test, elevated plus-maze (EPM) test, and forced swimming test (FST) were performed after treatment. The expression levels of 5-hydroxytryptamine (5-HT) and tryptophan hydroxylase 1 (TPH1) in the colon were detected by immunofluorescence, and the expression levels of Trp, kynurenine (Kyn), and indole-2,3-oxygenase (IDO) in the colon were detected by enzyme-linked immunosorbent assay. Results: Compared with the normal group, the AWR scores were increased significantly in the model group under different pressure values (P<0.01), the open-arm staying time and open-arm entries in the EPM test were decreased significantly (P<0.01, P<0.05), the motionless time in the FST was increased significantly (P<0.01), and the expression levels of colonic Trp, TPH1, IDO, 5-HT, and Kyn were increased significantly (P<0.01) in the models. Compared with the model group, the AWR scores were differently decreased (P<0.05 or P<0.01), the open-arm entries in the EPM test were increased (P<0.05), the motionless times in the FST were decreased (P<0.05), and the colonic expression levels of Trp, TPH1, IDO, and 5-HT were decreased (P<0.01 or P<0.05) in the moxibustion and probiotic groups; the open-arm staying time was significantly increased in the moxibustion group (P<0.01), and the colonic expression level of Kyn was significantly decreased in the probiotic group (P<0.01). Conclusion: Moxibustion at Zusanli (ST36) improves visceral pain and pain mood and down-regulates the expression levels of colonic TPH1, IDO, Trp, 5-HT, and Kyn in IBS mice.

Linderae Radix water extract treats diarrhea-predominant irritable bowel syndrome in rats: a serum metabolomics study / 中国中药杂志

This study aims to investigate the mechanism of Linderae Radix water extract(LRWE) in the prevention and treatment of diarrhea-predominant irritable bowel syndrome(IBS-D) based on serum metabolomics. Eighteen 2-week-old male SD rats were randomized into control, IBS-D model, and LRWE groups. The rats in other groups except the control group received gavage of senna concentrate combined with restraint stress for the modeling of IBS-D. The rats in the LRWE group were administrated with LRWE(5.4 g·kg~(-1)) by gavage, and those in the control and IBS-D model groups with an equal volume of distilled water for a total of 14 days. The visceral sensitivity was evaluated by the abdominal withdrawal reflex(AWR) score, and the degree of diarrhea was assessed by the fecal water content(FWC). The morphological changes of the colon and the morphology and number of goblet cells were observed by hematoxylin-eosin(HE) and periodic acid-schiff(PAS) staining, respectively. Ultra-high performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS) was used for the screening of the potential biomarkers in the rat serum and their related metabolic pathways. The results showed that LRWE reduced the AWR score, decreased FWC, and alleviated visceral sensitivity and diarrhea symptoms in IBS-D rats. HE and PAS staining showed that LRWE mitigated low-grade intestinal inflammation and increased the number of mature secretory goblet cells in the colonic epithelium of IBS-D rats. A total of 25 potential biomarkers of LRWE in treating IBS-D were screened out in this study, which were mainly involved in riboflavin, tryptophan, glycine, serine and threonine metabolism, glyoxylate and dicarboxylate metabolism, and cysteine and methionine metabolism. The regulatory effects were the most significant on the riboflavin and tryptophan metabolism pathways. LRWE may alleviate the visceral hypersensitivity by promoting energy metabolism and amino acid metabolism, enhancing intestinal barrier function, and improving intestinal immune function in IBS-D rats.

The kynurenine pathway in Alzheimer's disease: a meta-analysis of central and peripheral levels

Objective: Changes in the kynurenine pathway are recognized in psychiatric disorders, but their role in Alzheimer's disease (AD) is less clear. We aimed to conduct a systematic review and meta-analysis to determine whether tryptophan and kynurenine pathway metabolites are altered in AD. Methods: We performed a systematic review and random-effects meta-analyses. Inclusion criteria were studies that compared AD and cognitively normal (CN) groups and assessed tryptophan or kynurenine pathway metabolites in cerebrospinal fluid or peripheral blood. Results: Twenty-two studies with a total of 1,356 participants (664 with AD and 692 CN individuals) were included. Tryptophan was decreased only in peripheral blood. The kynurenine-to-tryptophan ratio was only increased in peripheral blood of the AD group. 3-Hydroxykynurenine was decreased only in cerebrospinal fluid and showed higher variability in the CN group than the AD group. Kynurenic acid was increased in cerebrospinal fluid and decreased in peripheral blood. Finally, there were no changes in kynurenine and quinolinic acid between the groups. Conclusions: Our results suggested a shift toward the kynurenine pathway in both the brain and in the periphery, as well as a shift towards increased kynurenic acid production in the brain but decreased production in peripheral blood. In addition, our analysis indicated dissociation between the central and peripheral levels, as well as between plasma and serum for some of these metabolites. Finally, changes in the kynurenine pathway are suggested to be a core component of AD. More studies are warranted to verify and consolidate our results.

La miocardiopatía hipertrófica induce cambios en la expresión de la triptófano-5-hidroxilasa, el transportador de serotonina y receptores serotoninérgicos / Hypertrophic cardiomyopathy induces changes in the tryptophan-5-hydroxylase, serotonin transporter and serotonergic receptors expressions

Resumen Introducción: Los cardiomiocitos poseen la maquinaria bioquímica capaz de sintetizar, utilizar y recapturar serotonina. Objetivo: Determinar si la miocardiopatía hipertrófica (MCH) induce cambios en la expresión de la triptófano-5-hidroxilasa (TPH) 1 y 2, el transportador de serotonina (SERT) y los receptores serotoninérgicos (RS). Métodos: Estudio transversal de cinco bloques de tejido de corazones con MCH y cinco bloques de corazones de control. Se obtuvieron cinco cortes de la pared libre del ventrículo izquierdo (PLVI) y del septum interventricular (SIV) de cada bloque, para determinar la expresión de TPH1 y TPH2, SERT y RS con anticuerpos por inmunofluorescencia. La inmunofluorescencia fue evaluada mediante t de WELCH, con nivel de significación de p < 0.05. Resultados: La PLVI y el SIV de los corazones con MCH mostraron aumento de la expresión de TPH1 y TPH2, así como de los receptores 5-HT2A y 5-HT2B en comparación con los controles (p < 0.01). El receptor 5-HT4 y SERT aumentaron en el SIV de los corazones con MCH (p < 0.01). Conclusiones: Se demostró aumento de las expresiones de TPH, SERT y RS en los cardiomiocitos de los corazones con MCH en comparación con los controles, lo cual podría participar en la fisiopatología de la MCH en los humanos.

Abstract Introduction: Cardiomyocytes have a biochemical machinery with the capacity to synthesize, utilize and reuptake serotonin. Objective: To determine whether hypertrophic cardiomyopathy (HCM) induces changes in the expression of tryptophan-5-hydroxylase (TPH) 1 and 2, serotonin transporter (SERT) and serotonergic receptors (SR). Methods: Cross-sectional study of five tissue blocks from hearts with HCM and five controls. Five sections of the left ventricular free wall (LVFW) and interventricular septum (IVS) were obtained from each block to determine the expression of TPH1 and TPH2, SERT and SRs by immunofluorescence with specific antibodies. Immunofluorescence was evaluated by WELCH t-test, with a level of significance of p < 0.05. Results: LVFW and IVS of hearts with HCM showed an increase in the expression of TPH1 and TPH 2 and 5-HT2A and 5-HT2B receptors in comparison with controls (p < 0.01). The 5-HT4 receptor and SERT showed an increase in the IVS of hearts with HCM (p < 0.01). Conclusions: This study demonstrated an increased expression of TPH, SERT and SRs in cardiomyocytes from hearts with HCM in comparison with controls, which could be involved in the pathophysiology of HCM in humans.

Cambios en la actividad y expresión de las triptófano-5-hidroxilasas cerebrales y en el número de neuronas serotoninérgicas por la diabetes mellitus, que no retornan a la normalidad con la insulina / Diabetes mellitus causes changes in brain tryptophan-5-hydroxylases activity and expression and in the number of serotonergic neurons, which do not return to normal with insulin treatment

Resumen Introducción: La diabetes mellitus (DM) inhibe la biosíntesis de serotonina cerebral mediante cambios en la actividad y expresión de triptófano-5-hidroxilasa (TPH). Objetivos: Determinar si los cambios en la expresión de TPH1 y TPH2 cerebral y en el número de neuronas serotoninérgicas causados por la DM retornan a la normalidad en ratas con diabetes tratadas con insulina. Métodos: Ratas con diabetes inducida con estreptozotocina se dividieron en dos grupos uno tratado con insulina y otro sin tratamiento. En el día 14, se obtuvieron tallos cerebrales para cuantificar niveles de L-triptófano, 5-hidroxitriptamina y la actividad de la TPH. La expresión de TPH1 y TPH2 fue mediante Western blot y el número de neuronas serotoninérgicas por inmunohistoquímica. Resultados: En las ratas con diabetes se confirmó disminución de los niveles de L-triptófano, 5-hidroxitriptamina y la actividad de la TPH, así como menor expresión de TPH1 y TPH2 y menor número de neuronas serotoninérgicas. Cuando las ratas diabéticas fueron tratadas con insulina, el L-triptófano regresó a la normalidad, no así la 5-hidroxitriptamina, la expresión de TPH ni el número de neuronas serotoninérgicas. Conclusiones: La DM inhibe crónicamente la síntesis de 5-hidroxitriptamina cerebral mediante modificaciones en la expresión de TPH1 y TPH2 y disminución de las neuronas serotoninérgicas, que persisten a pesar del tratamiento con insulina.

Abstract Introduction: Diabetes mellitus (DM) inhibits brain serotonin biosynthesis through changes in tryptophan-5-hydroxylase (TPH) activity and expression. Objectives: To determine whether DM-induced changes in brain TPH1 and TPH2 expression and in the number of serotonergic neurons return to normal in diabetic rats treated with insulin. Methods: Rats with streptozotocin-induced diabetes were divided in two groups: one treated with insulin and the other without treatment. On day 14, brain stems were obtained in order to quantify L-tryptophan and 5-hydroxytryptamine levels, as well as to determine TPH activity. The expressión of TPH1 and THP2 by Western blot, and the number of serotonergic neurons by immunohistochemistry. Results: In diabetic rats, a decrease in the levels of L-tryptophan, 5-hydroxytryptamine and TPH activity was confirmed, as well as lower TPH1 and TPH2 expression and lower numbers of serotonergic neurons. When diabetic rats were treated with insulin, L-tryptophan returned to normal, but not 5-hydroxytryptamine, TPH expression, or the number of serotonergic neurons. Conclusions: DM chronically inhibits the synthesis of brain 5-hydroxytryptamine through changes in TPH1 and TPH2 expression and a decrease in the number of serotonergic neurons, which persist despite insulin treatment.

Progress of tryptophan and its metabolites in pathogenesis of allergic asthma / 国际儿科学杂志

Airway epithelial damage, increased Th2 inflammatory response, and impaired immune regulatory T cell function are important mechanisms for the development of asthma.Indoleamine 2, 3-dioxygenase(IDO) is induced by LPS and IFN-γ, which regulates the differentiation of naive T cells into CD4 + CD25 + regulatory T cells(Treg)and induces immune tolerance.It can inhibit eosinophilic airway inflammation.Decreased IDO activity may promote the development of asthma.Tryptophan metabolites act on AhR receptors to promote the production of IL-22 and enhance the integrity of the epithelium and its resistance to infection.The Th17/Treg balance induced by specific immunotherapy could be altered, and Treg cell proliferation was observed.Tryptophan metabolites can reduce airway inflammation and inflammatory cytokine infiltration.D-tryptophan can promote the diversity of intestinal flora, increase the number of Treg in lung and colon, reduce Th2 reaction, and reduce airway hyperresponsiveness.Tryptophan and its metabolites, IDO and D-tryptophan play an important role in the occurrence, development and specific immunotherapy of asthma.

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.

Correlation between tryptophan daily intake and occupational factors with stress outcome scores among offshore and onshore workers

INTRODUCTION@#Offshore and onshore workers have a higher risk of psychological stress related to their job. Stress reactions vary depending on the type of stressor, the duration or severity of the stressor, their genetics, their coping styles, and their nutrition. Tryptophan is an essential amino acid precursor of serotonin and melatonin, which have an antidepressant effect and roles in stress perception and management. This study assessed the correlation of daily tryptophan intake and occupational factors with stress outcome scores based on the Indonesian Short Version New Brief Job Stress Questionnaire (SV-NBJSQ) among offshore and onshore workers.@*METHODS@#A cross-sectional study was conducted on 14 offshore workers and 20 onshore workers. Interviews and questionnaires were conducted to obtain demographic data, dietary intake, occupational factors, and stress outcome scores. Tryptophan daily intake was measured through a single 24-hour dietary recall and a one-day-weighted food record. Data of average daily intake for two days were analyzed using the NutriSurvey software based on the food composition table from The United States Department of Agriculture National Nutrient Database for calculating tryptophan intake.@*RESULTS@#The median (min-max) tryptophan daily intake of offshore workers was 5.5 (1.9–9.9) mg/kg, and 4.5 (1.4–7.5) mg/kg among onshore workers. There was no difference in tryptophan daily intake between offshore and onshore workers (p = 0.064). There was no significant difference between occupational factors except for the shorter tenure of offshore workers (12.5 vs 3, p < 0.001). There was no significant correlation between tryptophan daily intake and each of the stress outcome scores. There was a significant correlation between occupational factors and stress outcome scores among offshore and onshore workers, specifically between workload and fatigue (r = 0.35, p =0.04), workload and depression (r = 0.4, p = 0.02), interpersonal conflict and anxiety (r = 0.47, p = 0.005), role conflict and anxiety (r = 0.47, p = 0.005), as well as between tenure and physical reaction stress (r = -0.42, p = 0.02).@*CONCLUSION@#Adequate tryptophan daily intake and high stress outcome scores among offshore and onshore oil and gas workers are observed in this study, and no correlation was found between the two. Similar food sources, homogeneous occupational stressors, the selection bias of the “healthy worker effect” or other factors that were not studied may influence the findings. There is a correlation between occupational factors and stress outcome scores, namely workload and fatigue, workload and depression, interpersonal conflict and anxiety, role conflict and anxiety, and tenure and stress physical reactions.