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Monitoring biomarker levels in body fluids is of great importance in clinical diagnosis. Herein, a robust 3D ZnMOF, {[Zn 2 (BTPB) 0.5 (bib) 1.5 (μ 2 -OH)]·2H 2 O} n , was fabricated based on the ligands of 1,4-bis(2,4,6-tricarboxylpyrid-5-yl)benzene (H 6 BTPB) and 1,4-bis(imidazol-1-yl)benzene (bib). On the basis of its stable architecture and intrinsic luminescence, ZnMOF demonstrated remarkable potential as a bifunctional luminescent sensor for selective and sensitive detecting the biomarkers of 3-nitrotyrosine (3-NT) and 5-hydroxyindoleacetic acid (5-HIAA) in water and body fluids by employing distinct "turn-off" and "turn-on" responses. Additionally, the inherent sensing mechanism was further assessed from the viewpoints of spectral overlap and photo-induced electron transfer. This work manifested MOFs-based luminescent sensors are developing into an effective method for detecting biomarkers in body fluids with perfect practicality and compatibility., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Objective: The aim of this study was to evaluate the performance of different biomarkers for the detection of carcinoid heart disease (CHD) in neuroendocrine tumours (NETs), in particular serum 5-HIAA (s5HIAA)., Design: An explorative ancillary study of the French CrusoeNET cohort., Methods: Patients managed in the Lyon-EURACAN Center of Excellence (CoE) were included when they were aged of at least 18 years, treated and followed for an advanced/metastatic ileum or lung NET, a NET irrespective of the primary location or from unknown primary location but with clinical CS, and/or elevation of urinary 5-HIAA (u5HIAA) twice greater than the upper limit of normal. All patients included had 1 available serum stored within the local biobank between January 2021 and April 2022. Echocardiography was performed by 1 of the 3 expert cardiologists of the Lyon-EURACAN-CoE., Results: We included 138 patients with NETs, mainly of the small intestine and lung, and 19 of them had a CHD. Analysis showed that s5HIAA was well correlated with u5HIAA (ρ = 0.824 [0.76-0.88], P < .0001) and was a good biomarker for CHD detection (receiver operating characteristic curve = 0.85 [0.75-0.94], P < .0001). Using a threshold value of 757 nmol/L, the sensitivity and specificity for the detection of CHD were 84% and 80%, respectively., Conclusions: s5HIAA is highly sensitive and specific for CHD detection. It could be used as a pre-screening tool in centres where systematic and regular echocardiography by an expert cardiologist is not performed in this population., Competing Interests: Conflict of interest: C.L.-B. received financial support from IPSEN, Novartis, Keocyt, and AAA. T.W. received financial support from IPSEN, AAA, Novartis, Keocyt, and Roche to conduct clinical trials and/or ancillary studies. Other authors: none., (© The Author(s) 2024. Published by Oxford University Press on behalf of European Society of Endocrinology. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

The management of neuroendocrine neoplasms (NENs) involves the measurement of serum chromogranin A (s-CGA), serum neuro-specific enolase (s-NSE), and urinary 5-hydroxindolacetic acid (5-HIAA). Urinary para-hydroxyphenylacetic acid (u-pHPAA), a metabolite of tyrosine, has been proposed as a potential biomarker for these diseases. This study aims to evaluate the effectiveness of u-pHPAA and tyrosine as biomarkers. We measured the levels of s-CgA, s-NSE, u-5-HIAA, u-pHPAA, and tyrosine in blood or 24 h urine samples collected at baseline (T 0 ) and after 1 year of follow-up (T 1 ) from a limited cohort of patients enrolled at Istituto Nazionale Tumori-IRCCS-Fondazione "G. Pascale". Biomarker values were normalized using the ratios between T 1 and T 0 values (T 1 /T 0 parameters). The T 1 /T 0 ratios for s-CgA and u-pHPAA were significantly associated with the outcome of death ( p = 0.044 and p = 0.022, respectively). An ROC curve analysis demonstrated outstanding performances for these biomarkers (AUC = 0.958 and AUC = 1.00, respectively) and the Kaplan-Meier survival analysis showed significant Log-rank test results ( p = 0.001 and p < 0.001, respectively). Additionally, T 0 serum tyrosine correlated with the outcome of death ( p = 0.044), with the ROC curve showing good performance (AUC = 0.958) and the Kaplan-Meier analysis yielding significant Log-rank test results ( p = 0.007). Our study confirms the role of s-CgA in the management of NEN patients and highlights the potential roles of u-pHPAA and serum tyrosine as biomarkers. Further research is needed to validate our findings in larger populations.

This study investigates the clinical efficacy of Tiaoshu Anshen Decoction in treating insomnia characterized by spleen and stomach Qi dysfunction. According to the differences of previous treatment, 94 patients were divided into treatment group and control group. The treatment group was treated with Tiaoshu Anshen Decoction, and the control group was treated with oral esazolam for 2 weeks. We compared serum levels of 5-hydroxyindoleacetic acid (5-HIAA), 5-hydroxytryptamine (5-HT), norepinephrine (NE), dopamine (DA), DASS-21, and HAMD scores before and after treatment. We also evaluated gastrointestinal function, traditional Chinese medicine syndrome scores, quality of life, and adverse reactions, with statistical analysis conducted using SPSS 25.0. The overall efficacy and clinical outcomes were comparable between the 2 groups. Both groups showed increased serum factor levels and decreased Pittsburgh Sleep Quality Index (PSQI), HAMD, and DASS-21 scores post-treatment. Notably, the treatment group exhibited significant improvement in stool consistency, digestive symptoms, DOB < 4 and DOB ≥ 4 distribution, and TCM syndrome scores, outperforming the control group. No adverse reactions were reported in either group. This study suggests that spleen and stomach Qi dysfunction significantly contribute to insomnia, affecting its occurrence, type, and severity. Tiaoshu Anshen Decoction effectively enhances 5-HIAA, 5-HT, NE, and DA levels, reduces inflammatory factors, and improves sleep quality, gastrointestinal function, and overall quality of life. The decoction may exert its effects by regulating Qi dynamics and gastrointestinal function, indicating the gastrointestinal system as a potential key target in treating sleep disorders., Competing Interests: The authors have no conflicts of interest to disclose., (Copyright © 2024 the Author(s). Published by Wolters Kluwer Health, Inc.)

Depression is associated with intestinal dysbiosis. Venlafaxine is a commonly used antidepressant in clinical practice as a serotonin and noradrenaline reuptake inhibitor. However, its effects on gut bacteria in depression remain unclear. Here, we established a mouse model of depression induced by chronic unpredictable mild stress (CUMS), and investigated the alterations of venlafaxine on the gut microbiota and potential key bacteria. Our data show that venlafaxine exerts antidepressant effects by restoring the serotonin (5-HT) system and glutamate (Glu) levels in CUMS mice. Moreover, we revealed that venlafaxine altered the diversity of gut bacteria in CUMS mice, and at genus level, Blautia, Oscillibacter, Tyzzerella, Butyricicoccus, and Enterorhabdus are the key bacteria responsible for venlafaxine-ameliorated depression in mice. Among these potential key bacteria, Blautia, Oscillibacter, and Butyricicoccus are correlated significantly with the 5-HT and 5-hydroxyindoleacetic acid levels; while Tyzzerella is correlated markedly with Glu levels. We further show that venlafaxine affected multiple functional metabolic pathways of gut bacteria in mice with CUMS-induced depression. Our results suggest that venlafaxine possibly ameliorates depression via modulating gut bacteria, and found the potential targets of its antidepressant effects., Competing Interests: Conflicts of interest The authors declare that there is no conflict of interest., (Copyright © 2023 Elsevier B.V. All rights reserved.)

A very quick and easy LC-MS/MS analysis method for 5-HIAA (5-hydoxyindoleacetic acid) has been developed. The method was fully validated and proved to work well in a clinical setting. Precision at the upper reference limit 123 nmol/L was 3,3% CV. Accuracy ranged from 96% at low levels (50-100 nmol/L) to 99.7% at high levels (500 nmol/L). A previously reported reference interval of 35-123 nmol/L was confirmed as valid based on analysis of 40 samples from voluntary blood donors.

Objective: Literature on patient-reported outcomes (PRO) of carcinoid syndrome symptoms (CSS) is scarce. We used a patient-reported outcome measure (PROM) to evaluate CSS, the domains of daily life impacted by CSS, the main symptoms that affect daily life, its change according to clinical, biological and morphological evolution, and the risk factors for a poor PRO-CSS score., Methods: Patients completed the PRO-CSS, EORTC-QLQ30, and GI-NET21 questionnaires at the time of their clinical, laboratory, and morphological assessments in a multicentre French cohort study from February 2019 to May 2020., Results: In total, 147 patients with metastatic ileal (n =126), lung (n =20), or unknown primitive neuroendocrine tumour but high 5-hydroxyindole-3-acetic acid level (n =1) were included; 42 (32%) received an above-label dose of somatostatin analogues. Fifty-one (35%) patients had a poor PRO-CSS score. Travelling and food restriction were the two main domains affected. Diarrhoea (mean: 2.3/5 on Likert scale), imperiousness (mean of 2.5/5), fatigue (2.2/5), abdominal pain (1.7/5), and flushing episodes (1.5/5) were the main symptoms affecting daily life. The PRO-CSS score was not correlated to the clinical assessment performed by physicians at the baseline and during the follow-up. Patients with a poor PRO-CSS score had a higher tumour burden., Conclusions: PROM-CSS may help physicians make an objective assessment of CSS and its impact in daily practice; this tool could become a key evaluation criterion in clinical trials focusing on CSS.

Context: Although 24-hour urinary 5-hydroxyindolacetic acid (24u5HIAA) is a key biomarker in midgut neuroendocrine tumors (NETs), it may be inaccurate and inconvenient., Objective: We compared the diagnostic performances of 24u5HIAA, overnight urinary 5HIAA (Ou5HIAA), and plasmatic 5HIAA (p5HIAA) in midgut NETs., Methods: This prospective, multicenter study included 80 patients with metastatic midgut NETs and 17 control patients with irritable bowel syndrome. 24u5HIAA, Ou5HIAA, and p5HIAA were measured in urine and plasma collected on 2 consecutive days following a specific recommended diet. Reproducibility of the biomarkers was evaluated by the Spearman test. Diagnostic performance was assessed by the area under the receiver operating characteristic curve (AUROC). Correlations with the main clinical features and declared observance to the specific diet were assessed using AUROC and logistic regression models., Results: The reproducibility of 24u5HIAA, Ou5HIAA, and p5HIAA were excellent (ρ = 0.916; 0.897; 0.978, respectively, P < .001) with significant discrimination between patients and controls (AUROC = 0.795, P < .001; 0.757, P = .001; 0.717, P = .005, respectively). All 3 markers were correlated with the presence of carcinoid syndrome (AUROC = 0.702, P = .006; 0.701, P = .006; 0.697, P = .007, respectively), carcinoid heart disease (AUROC = 0.896; 0.887; 0.923, P < .001, respectively, P < .001), and liver metastatic involvement greater than 30% (AUROC = 0.827; 0.807; 0.849, P < .001, respectively, P < .001), independent from other traditional prognostic factors. Biomarker levels were similar between patients with optimal or suboptimal diet observance., Conclusion: Ou5HIAA and p5HIAA could be used as more convenient alternatives to 24u5HIAA in patients with metastatic midgut NETs. Prospective long-term studies with repeated dosages are needed., (© The Author(s) 2020. Published by Oxford University Press on behalf of the Endocrine Society. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

PGC-1α expression increases in skeletal muscles during exercise and regulates the transcription of many target genes. In this study, we conducted a metabolomic analysis on the blood of transgenic mice overexpressing PGC-1α in its skeletal muscle (PGC-1α-Tg mice) using CE-TOFMS. The blood level of homovanillic acid (dopamine metabolite) and the gene expression of dopamine metabolic enzyme in the skeletal muscle of PGC-1α-Tg mice were high. The blood level of 5-methoxyindoleacetic acid was also high in PGC-1α-Tg mice. The blood levels of branched-chain α-keto acids and β-alanine were low in PGC-1α-Tg mice. These metabolites in the skeletal muscle were present in low concentration. The changes in these metabolites may reflect the skeletal muscle condition with increasing PGC-1α, such as exercise., (© The Author(s) 2021. Published by Oxford University Press on behalf of Japan Society for Bioscience, Biotechnology, and Agrochemistry.)

Psilocin is the active metabolite of psilocybin, a serotonergic psychedelic substance. It is used recreationally and investigated in substance-assisted psychotherapy. The pharmacokinetic properties of psilocin are only partially characterized. Therefore, we developed and validated a rapid LC-MS/MS method to quantify psilocin and its metabolite 4-hydroxyindole-3-acetic acid (4-HIAA) in human plasma. Plasma samples were processed by protein precipitation using methanol. The injected sample was mixed with water in front of a C 18 analytical column to increase retention of the analytes. Psilocin and 4-HIAA were detected by multiple reaction monitoring (MRM) in positive and negative electrospray ionisation mode, respectively. An inter-assay accuracy of 100-109% and precision of ≤8.7% was recorded over three validation runs. The recovery was near to complete (≥94.7%) and importantly, consistent over different concentration levels and plasma batches (CV%: ≤4.1%). The plasma matrix caused negligible ion suppression and endogenous interferences could be separated from the analytes. Psilocin and 4-HIAA plasma samples could be thawed and re-frozen for three cycles, kept at room temperature for 8 h or 1 month at -20 °C without showing degradation (≤10%). The linear range (R ≥ 0.998) of the method covered plasma concentrations observed in humans following a common therapeutic oral dose of 25 mg psilocybin and was therefore able to assess the pharmacokinetics of psilocin and 4-HIAA. The LC-MS/MS method was convenient and reliable for measuring psilocin and 4-HIAA in plasma and will facilitate the clinical development of psilocybin., (Copyright © 2020 The Authors. Published by Elsevier B.V. All rights reserved.)

Background: Carcinoid heart disease (CHD) can develop in patients with carcinoid syndrome (CS), itself caused by overproduction of hormones and other products from some neuroendocrine tumours. The most common hormone is serotonin, detected as high 5-hydroxyindoleacetic acid (5-HIAA). This systematic literature review summarises current literature on the impact of CHD on survival, and the relationship between 5-HIAA levels and CHD development, progression, and mortality., Methods: MEDLINE, Embase, Cochrane databases, and grey literature were searched using terms for CHD, 5-HIAA, disease progression, and mortality/survival. Eligible articles were non-interventional and included patients with CS and predefined CHD and 5-HIAA outcomes., Results: Publications reporting on 31 studies were included. The number and disease states of patients varied between studies. Estimates of CHD prevalence and incidence among patients with a diagnosis/symptoms indicative of CS were 3-65% and 3-42%, respectively. Most studies evaluating survival found significantly higher mortality rates among patients with versus without CHD. Patients with CHD reportedly had higher 5-HIAA levels; median urinary levels in patients with versus without CHD were 266-1,381 versus 67.5-575 µmol/24 h. Higher 5-HIAA levels were also found to correlate with disease progression (median progression/worsening-associated levels: 791-2,247 µmol/24 h) and increased odds of death (7% with every 100 nmol/L increase)., Conclusions: Despite the heterogeneity of studies, the data indicate that CHD reduces survival, and higher 5-HIAA levels are associated with CHD development, disease progression, and increased risk of mortality; 5-HIAA levels should be carefully managed in these patients., (© 2020 The Author(s) Published by S. Karger AG, Basel.)

The purpose of this study was to identify factors predicting 6-month smoking cessation in Korean adult smokers. This descriptive correlation study assessed levels of urine cotinine, serum cotinine, serum serotonin, and 5-hydroxyindoleacetic acid; tobacco withdrawal symptoms; and resilience among 164 Korean adult smokers. Serum cotinine levels were negatively related to resilience at six months (r = -.42, p = .019), but were positively related to the amount of smoking (r = .32, p = .008) and with the Week 6 tobacco withdrawal symptoms score (r = .48, p = .001, n = 41). Higher resilience was associated with a higher 5-HIAA concentration. Greater therapy attendance, resilience, and withdrawal symptoms explained 35.3% of the variance in 6-month smoking cessation (Nagelkerke R 2  = .35, p < .001, n = 76). Efforts to increase counseling attendance rates and resilience and decrease withdrawal symptoms could be useful ways to improve smoking cessation rates.

Aim: Mismatch negativity (MMN) deficit is one of the most robust and replicable findings in schizophrenia, and primarily reflects deficient functioning of the N-methyl-D-aspartate (NMDA) receptor system. Although the dopamine receptor is known not to modulate MMN over the short term, it is unclear whether the dopamine system affects MMN in the long term., Methods: We explored correlations between MMN and levels of plasma dopamine and serotonin metabolites in 18 patients with schizophrenia psychiatrically evaluated with the Positive and Negative Syndrome Scale (PANSS)., Results: A significant negative correlation exists between MMN amplitude and plasma levels of dopamine metabolites. Plasma serotonin metabolite levels were not correlated with MMN. The PANSS total score and Negative score also showed negative correlations with MMN amplitude., Conclusion: The usual strong therapeutic blockade of dopamine receptors applied in cases of schizophrenia may reduce MMN over the long term., (© 2020 The Authors. Psychiatry and Clinical Neurosciences © 2020 Japanese Society of Psychiatry and Neurology.)

Septic shock is associated with a strong inflammatory response that induces vasodilation and vascular hyporeactivity. We investigated the role for tryptophan-pathway catabolites of proinflammatory cytokines in septic shock.We prospectively included 30 patients with very recent-onset septic shock and 30 healthy volunteers. The following were assayed once in the controls and on days 1, 2, 3, 7, and 14 in each patient: plasma free and total tryptophan, platelet and plasma serotonin, total blood serotonin, urinary serotonin, plasma and urinary 5-hydroxyindolacetic acid, plasma kynurenine, monoamine oxidase activity, and total indole amine 2,3-dioxygenase activity. Organ-system failure and mortality were recorded.Compared with the healthy controls, the patients with septic shock had 2-fold to 3-fold lower total tryptophan levels throughout the 14-day study period. Platelet serotonin was substantially lower, while monoamine oxidase activity and 5-hydroxyindolacetic acid were markedly higher in the patients than in the controls, consistent with the known conversion of tryptophan to serotonin, which is then promptly and largely degraded to 5-hydroxyindolacetic acid. Plasma kynurenine was moderately increased and indole amine 2,3-dioxygenase activity markedly increased in the patients versus the volunteers, reflecting conversion of tryptophan to kynurenine. Changes over time in tryptophan metabolites were not associated with survival in the patients but were associated with the Sequential Organ Failure Assessment score and hemodynamic variables including hypotension and norepinephrine requirements.Our results demonstrate major tryptophan pathway alterations in septic shock. Marked alterations were found compared with healthy volunteers, and tryptophan metabolite levels were associated with organ failure and hemodynamic alterations. Tryptophan metabolite levels were not associated with surviving septic shock, although this result might be ascribable to the small sample size.Trial registration: ClinicalTrials.gov; No: NCT00684736; URL: www.clinicaltrials.gov.

Background: Currently, several indole markers are measured separately to support diagnosis and follow-up of patients with neuroendocrine tumors (NETs). We have developed a sensitive mass spectrometry method that simultaneously quantifies all relevant tryptophan-related indoles (tryptophan, 5-hydroxytryptophan, serotonin, 5-hydroxyindoleacetic acid) in platelet-rich plasma. Direct-matrix derivatization was used to make the chemical properties of the indoles uniform and to improve the analytical sensitivity and specificity of the assay., Methods: In situ derivatization was performed directly in platelet-rich plasma with propionic anhydride at an ambient temperature. The derivatized indoles were extracted by online solid-phase extraction and eluted to the analytical column for separation followed by mass spectrometric detection. The method was validated according to international guidelines. Platelet-rich plasma samples from 68 healthy individuals and 40 NET patients were analyzed for tryptophan, 5-hydroxytryptophan, serotonin, and 5-hydroxyindoleacetic acid., Results: The method reproducibly quantified relevant indoles in 8.5 min, including online sample cleanup. Intra- and interassay imprecision, evaluated at 3 different concentrations, ranged from 2.0% to 12% and 1.9% to 13%, respectively. The limit of quantification was sufficient to measure endogenous concentrations of all 4 indoles. Healthy individuals and NET patients had different concentrations of 5-hydroxytryptophan, serotonin, and 5-hydroxyindoleacetic acid, but tryptophan concentrations were the same., Conclusions: Direct-matrix derivatization in combination with LC-MS/MS is a powerful tool for the simultaneous quantification of all tryptophan-related indoles in platelet-rich plasma. Simultaneous profiling of relevant indoles improves the biochemical characterization and follow-up of NETs., (© 2019 American Association for Clinical Chemistry.)

Biomarkers for neurodegenerative dementias offer interesting prospects regarding diagnosis and disease monitoring. Monoamines such as dopamine, (nor)adrenaline, serotonin (5-hydroxytryptamine or 5-HT), and their respective metabolites homovanillic acid (HVA) and 3,4-dihydroxyphenylacetic acid, 3-methoxy-4-hydroxyphenylglycol (MHPG), and 5-hydroxyindoleacetic acid (5-HIAA), were shown to be altered in dementia, including Alzheimer's disease (AD). Biomarker research is hampered by potential confounds including the influence of time of day and volume of cerebrospinal fluid (CSF) collected. Therefore, the possibility of a circadian rhythm in CSF and plasma, and the presence of a rostrocaudal concentration gradient (RCG) in CSF for aforementioned monoamines/metabolites, were investigated. Circadian rhythmicity was assessed using reversed-phase ultra-high performance liquid chromatography with electrochemical detection (RP-UHPLC-ECD) to measure monoamine/metabolite concentrations in 271 paired CSF and plasma samples, successively collected over a period of 30 h and derived from eight healthy subjects. Plasma samples were also analyzed for melatonin, serving as positive control analyte, using ELISA. The RCG examination entailed RP-UHPLC-ECD analyses on five consecutive CSF samples derived from 10 patients with AD and 10 non-AD/control subjects. Besides a diurnal rhythm for melatonin, we found a similar rhythmicity for plasma HVA, with acrophases occurring between 02:00 and 06:00 h, in four out of seven subjects. Three and two subjects showed a circadian rhythm for CSF HVA and 5-HIAA, respectively. No rhythmicity was observed in any other compound. We found that only CSF MHPG, HVA and 5-HIAA levels differed across CSF fractions, and that these changes in 5-HIAA levels varied in the AD versus non-AD/control group. Positive correlations between CSF volume and HVA and 5-HIAA levels, indicative of a RCG, were also observed. Such a RCG could not be detected for the other monoamines/metabolites. Our results stress the importance of standardizing sampling procedures of biological fluids with respect to time of day, volume and number of samples., (Copyright © 2019 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Post traumatic stress disorder (PTSD) is one of the mental illness. The antidepressant-like properties of ginsenoside Rg2 (GRg2) have been shown, while little is known about its anti-PTSD-like effects. In the present study, the PTSD-associated behavioral deficits in rats were induced following exposure to single prolonged stress (SPS). The results showed that the decreased time and entries in the open arms in elevated plus maze test (EPMT) and increased freezing duration in contextual fear paradigm (CFP) were reversed by GRg2 (10 and 20 mg/kg) without affecting the locomotor activity. In addition, GRg2 (10 and 20 mg/kg) could block the decreased levels of progesterone, allopregnanolone, serotonin (5-HT), 5-Hydroxyindoleacetic acid (5-HIAA), corticotropin releasing hormone (CRH), corticosterone (Cort) and adrenocorticotropic hormone (ACTH) in the brain or serum. In summary, GRg2 alleviated the PTSD-associated behavioral deficits with biosynthesis of neurosteroids, normalization of serotonergic system and HPA axis dysfunction., (Copyright © 2018. Published by Elsevier B.V.)

The aim of the presented work was to develop a highly sensitive, accurate and rapid analytical method for the determination of concentration levels of tryptophan and its metabolites of kynurenine catabolic pathway, as well as neurotransmitters and their metabolites in complex biological matrices (brain tissue and blood plasma). The developed analytical method consists of analytes separation from the biological matrices by protein precipitation (blood plasma) or solvent extraction (brain tissue), derivatization of the analytes and their detection by high-performance liquid chromatography combined with mass spectrometry. Individual steps of the whole process were optimized and the method was validated in the terms of selectivity, linearity (R 2 ≥0.980), precision (RSD ≤ 13.3%), recovery (≥82.0%), limit of detection (1.8 ng/mL of blood plasma, 2.2 pg/mg of brain tissue) and limit of quantification (2.5 ng/mL of blood plasma, 2.8 pg/mg of brain tissue). The method was subsequently verified by an animal study, where the concentration levels of the analytes in biological matrices (blood plasma and brain tissue) of T. gondii - infected rats and control animals were compared. All the data obtained from the animal study were statistically evaluated. Increased concentration levels of kynurenine catabolic pathway metabolites (e.g. kynurenine, 3-hydroxykynurenine, quinolinic acid) were observed in the case of T. gondii - infected rats in contrast to the control group. The opposite effect was determined in the case of serotonin and its metabolite 5-hydroxyindoleacetic acid, where higher concentration levels were found in blood plasma of healthy subjects. Finally, Principal Component Analysis (PCA) was utilized for a score plot formation. PCA score plots have demonstrated the similarities of individuals within each group and the differences among the groups., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Neuroendocrine tumors (NETs) are relatively rare and highly heterogeneous neoplasms. Despite this, recent studies from North America and Central Europe have suggested an increase in incidence. In Latin America, NET data are scarce and scattered with only a few studies reporting registries. Our goal was to establish a NET registry in Chile. Here, we report the establishment and our first 166 NET patients. We observed a slight preponderance of males, a median age at diagnosis of 53 years and a median overall survival of 110 months. As anticipated, most tumors were gastroenteropancreatic (GEP). Survival analyses demonstrated that non-GEP or stage IV tumors presented significantly lower overall survival (OS). Similarly, patients with surgery classified as R0 had better OS compared to R1, R2, or no surgery. Furthermore, patients with elevated chromogranin A (CgA) or high Ki67 showed a trend to poorer OS; however, these differences did not reach statistical significance (log-rank test p = 0.07). To the best of our knowledge, this is the first report of a NET registry in Chile. Median OS in our registry (110 months) is in line with other registries from Argentina and Spain. Other variables including age at diagnosis and gender were similar to previous studies; however, our data indicate a high proportion of small-bowel NETs compared to other cohorts, reflecting the need for NET regional registries. Indeed, these registries may explain regional discrepancies in incidence and distribution, adding to our knowledge on this seemingly rare, highly heterogeneous disease.

Background: Some previous studies found decreased concentrations of L-tryptophan (TRY) and increased L-kynurenine (KYN), or its metabolites, in the body fluids of subjects with major depressive disorder (MDD), sometimes in association with suicidal behavior. Such changes might indicate a shift of TRY away from serotonin production, possibly via the effects of inflammatory peptides which activate indoleamine-2,3-dioxygenase. However, these findings have been inconsistent and require replication., Methods: We used sensitive liquid-chromatography mass spectrometry methods to assay plasma concentrations of TRY, 5-hydroxyindoleacetic acid (5-HIAA), and KYN and its metabolites (anthranilic acid and xanthurenic acid). We compared 49 hospitalized, depressed subjects diagnosed with MDD (n = 37) or bipolar disorder (BD, n = 12), with (n = 22) or without (n = 27) previous suicide attempts, to 78 healthy, ambulatory controls of similar age and sex (total n = 127)., Findings: Contrary to expectation, TRY plasma concentrations were higher, KYN plasma concentrations were lower, and their ratio much higher in depressed subjects, with no relationship to suicidal history. Concentrations of 5-HIAA and the kynurenine metabolites did not differ between depressed and healthy subjects., Conclusions: These findings are opposite to expectations and not consistent with a hypothesized increased conversion from TRY to KYN in depressed subjects. In addition, we found no evidence of altered production of serotonin as 5-HIAA concentration was unchanged. None of the observed changes was associated with a history of suicide attempt., (© 2018 S. Karger AG, Basel.)

In the present study, we evaluated the antioxidant and anti-stress activities of taurine in electric foot-shock stress model rats. Taurine supplementation markedly increased the hepatic glutathione (GSH) levels, compared to the levels in the stress group. In addition, activities of antioxidant enzymes such as catalase (CAT), glutathione peroxidase (GPx) and glutathione-S-transferase (GST) were improved in the taurine-treated group. Plasma cortisol and dehydroepiandrosterone-sulfate (DHEA-S) levels were significantly reduced in the taurine-supplemented group compared to those in the stress group. In contrast, the levels of 5-hydroxytryptamine (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) were markedly increased in the taurine or betaine-treated group compared to those in the stress group. It may be concluded that taurine produces beneficial effects in the form of antioxidant status and biochemical alterations in foot-shock-induced acute stress in rats.

A high-performance liquid chromatography method with a diode array and an electrochemical detection (HPLC-ECD/DAD) was developed to determine the levels of tryptophan (TRP), kynurenine (KYN), kynurenic acid (KYA), 5-hydroxytryptamine (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) in rat plasma. The prepared samples were separated on a BDS column (4.6 mm × 250 mm, 5 mm) with column oven temperature of 25 °C. The mobile phase consisted of 5% acetonitrile and a buffer solution, which contained 25 mmol/L sodium acetate and 0.01 mmol/L EDTA, adjusting pH to 4.5 with acetic acid, and it was pumped at a flow-rate of 1.0 mL/min. KYN and KYA were measured by a variable wavelength detector at wavelengths 360 nm and 333 nm respectively, TRP and vanillic acid (as IS) both were measured at 280 nm. Determination of 5-HT and 5-HIAA was accomplished at the electrochemical working potential of 700 mV. Total run time was 14 min. Several parameters of the developed method were validated including linearity, accuracy precision, and stability. The results showed the established method had good LOD and separation for all of the five compounds and IS in the biological matrix. The method is simple, fast, economical and accurate. The analytical method and the results could provide a reference for the clinical and scientific research of depression., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Background: Serotonin (5-hydroxytyramine) is a mediator of gastrointestinal smooth muscle contraction, and is secreted by neuroendocrine neoplasms (NENs). We developed a liquid chromatography tandem mass spectrometry (LC-MS/MS) assay for serum serotonin to be used in NEN diagnostics and follow-up., Methods: We used serum samples from healthy volunteers (n = 31) and patients suspected or monitored for NEN (n = 98). Serotonin-D 4 internal standard was added to samples before solid phase extraction (SPE) and quantification by LC-MS/MS. The effects of sample handling and preparation on serotonin stability were studied. Finally, we established a provisional reference range for serum serotonin and compared our assay with serum 5-hydroxyindoleacetic acid (5-HIAA) for detection of NENs., Results: Our assay is sensitive and has a wide linear range (10-10,000 nmol/l). Serum serotonin is stable for 7 days at room temperature and for 3 months at -20 °C. Sampling temperature is not critical. Normal range for serum serotonin was 270-1490 nmol/l. We found that serum serotonin and 5-HIAA performed equally well as diagnostic tests for NENs., Conclusions: Our LC-MS/MS assay for serum serotonin is well suited for clinical research and patient diagnostics. Our results confirm that it can complement 5-HIAA in diagnosis of NENs., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Aim: To compare health-related quality of life (HRQoL), anxiety, depression, and impulsivity scores in patients with and without carcinoid syndrome (CS), and correlated them with serum 5-hydroxyindoleacetic acid (5-HIAA) levels., Methods: Patients with advanced gastroenteropancreatic neuroendocrine tumours (GEPNET), with and without CS completed HRQoL QLQ-C30 and QLQ-GI.NET21, Hospital Anxiety and Depression Scale (HADS) and Barratt Impulsivity Scale (BIS) questionnaires. Two-sample Wilcoxon test was applied to assess differences in serum 5-HIAA levels, two-sample Mann-Whitney U test for HRQoL and BIS, and proportion test for HADS, between those with and without CS., Results: Fifty patients were included; 25 each with and without CS. Median 5-HIAA in patients with and without CS was 367nmol/L and 86nmol/L, respectively ( P = 0.003). Scores related to endocrine symptoms were significantly higher amongst patients with CS ( P = 0.04) and scores for disease-related worries approached significance in the group without CS, but no other statistically-significant differences were reported between patients with and without CS in responses on QLQ-C30 or QLQ-GI.NET21. Fifteen patients (26%) scored ≥ 8/21 on anxiety scale, and 6 (12%) scored ≥ 8/21 on depression scale. There was no difference in median 5-HIAA between those scoring < or ≥ 8/21 on anxiety scale ( P = 0.53). There were no statistically significant differences between groups in first or second-order factors (BIS) or total sum ( P = 0.23)., Conclusion: Excepting endocrine symptoms, there were no significant differences in HRQoL, anxiety, depression or impulsivity between patients with advanced GEPNET, with or without CS. Over one quarter of patients had high anxiety scores, unrelated to peripheral serotonin metabolism., Competing Interests: Conflict-of-interest statement: There are no conflicts of interest to declare.

Background: Lewy body disorders, including Parkinson's disease (PD), Parkinson's disease dementia (PDD) and dementia with Lewy bodies (DLB), are characterized by profound central and peripheral monoaminergic dysfunction., Objective: To investigate whether these alterations depend on dementia status, we measured cerebrospinal fluid (CSF) and serum monoamine and metabolite levels across subgroups of the cognitive spectrum, and evaluated their marker potential afterwards., Methods: In total, 153 subjects were included, of which 43 healthy controls (HC), 28 PD patients with normal cognition (PD-NC), 26 patients with PD and mild cognitive impairment (PD-MCI), 18 PDD patients, and 38 DLB patients. The levels of monoamines and metabolites in paired CSF and serum samples were analyzed applying reversed-phase high-performance liquid chromatography with electrochemical detection., Results: Firstly, when comparing subgroups, CSF 3-methoxy-4-hydroxyphenylglycol (MHPG) levels were found lowest in HC and PD-NC groups and significantly higher in PDD/DLB patients. In addition, CSF 5-hydroxyindoleacetic acid (5-HIAA) levels differed significantly between HC and PD-MCI/PDD, and DLB patients (P≤0.001), but not between HC and PD-NC patients. Secondly, when performing logistic regression, it was shown that particularly CSF/serum MHPG levels and the serum MHPG to noradrenaline (NA) ratio effectively differentiated between HC and (non-)pooled PD subgroups (AUC = 0.914-0.956), and PDD and DLB patients (AUC = 0.822), respectively. Furthermore, CSF 5-HIAA was the most discriminative parameter to differentiate between PD-NC and PD-MCI (AUC = 0.808), and, PD-NC and PDD subgroups (AUC = 0.916)., Conclusions: Our data revealed that especially alterations of the noradrenergic neurotransmitter system could distinguish between Lewy body disorder subtypes, pinpointing CSF/serum MHPG and NA as potential stage markers across the cognitive spectrum.

Sudden infant death syndrome (SIDS), the leading cause of postneonatal infant mortality, likely comprises heterogeneous disorders with the common phenotype of sudden death without explanation upon postmortem investigation. Previously, we reported that ∼40% of SIDS deaths are associated with abnormalities in serotonin (5-hydroxytryptamine, 5-HT) in regions of the brainstem critical in homeostatic regulation. Here we tested the hypothesis that SIDS is associated with an alteration in serum 5-HT levels. Serum 5-HT, adjusted for postconceptional age, was significantly elevated (95%) in SIDS infants ( n = 61) compared with autopsied controls ( n = 15) [SIDS, 177.2 ± 15.1 (mean ± SE) ng/mL versus controls, 91.1 ± 30.6 ng/mL] ( P = 0.014), as determined by ELISA. This increase was validated using high-performance liquid chromatography. Thirty-one percent (19/61) of SIDS cases had 5-HT levels greater than 2 SDs above the mean of the controls, thus defining a subset of SIDS cases with elevated 5-HT. There was no association between genotypes of the serotonin transporter promoter region polymorphism and serum 5-HT level. This study demonstrates that SIDS is associated with peripheral abnormalities in the 5-HT pathway. High serum 5-HT may serve as a potential forensic biomarker in autopsied infants with SIDS with serotonergic defects., Competing Interests: The authors declare no conflict of interest.

Depression is one of the leading causes of disability in developing countries including Pakistan. This study was designed to assess the frequency and severity of depressive symptoms, monoamines and their metabolite levels, MAO-B activities before and after treatment with antidepressants in a sub-set of Karachi population in Pakistan. Drug naive depressed subjects were evaluated before and after treatment with selective serotonin reuptake inhibitors. Symptoms of depressed mood and anxiety psychic (90%) were more frequent whereas, suicidal thoughts (~50%) and feelings of guilt (~30%) were less common. Hamilton Depression Rating Scale scores were 21.4 ± 0.8 in both genders with a significantly higher score (1.3x) in females. Homovanillic acid, 5- hydroxyindoleacetic acid and MAO-B activity were significantly higher 43%, 66% and 25% respectively, in depressed than normal subjects. A significant decline after 2 weeks treatment in HDRS scores with fluoxetine (19%) and paroxetine (40%) and in MAO-B activity (20%) was observed. In conclusion, in our population early decline in HDRS scores supports that they are SSRIs responders, whereas a concomitant reduction in MAO-B activities indicates that it can be considered as one of the parameters for early detection of response. Additionally, the low frequency of suicidal thoughts could be associated with higher levels of monoamine metabolites.

Objective: To investigate the effects of acute noise stress on two amine stress hormones, norepinephrine (NE) and 5-hydroxyindoleacetic acid (5-HIAA) in the brain and plasma of mice after noise exposure., Methods: Mice were grouped into the control and noise groups. Mice in the noise group were exposed to white noise of 110dB sound pressure level for 60min. Auditory brainstem response thresholds, distortion product otoacoustic emissions, the organ of Corti grading scores, western blots of NE/5-HIAA in the whole brain and hippocampus, and the plasma levels of NE/5-HIAA were compared between the two groups., Results: Significant hearing loss and cochlear damage were demonstrated in the noise group. NE and 5-HIAA in the hippocampus were elevated in the noise group (p=0.019/0.022 for NE/5-HIAA vs. the control). Plasma levels of NE and 5-HIAA were not statistically different between the groups (p=0.052/0.671 for NE/5-HIAA)., Conclusion: Hearing loss with outer hair cell dysfunction and morphological changes of the organ of Corti after noise exposure in C57BL/6 mice proved the reliability of our animal model as an acute noise stress model. NE and 5-HIAA are suggested to be the potential biomarkers for acute noise stress in the hippocampus., (Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.)

Esophageal squamous cell carcinoma (ESCC) is one of the most frequent malignancies worldwide. Lymph node metastasis is the leading cause of death in ESCC patients. To identify early diagnostic and prognostic biomarkers of ESCC and elucidate underlying pathogenesis of the disease, a targeted metabolomics strategy based on liquid chromatography combined with tandem mass spectrometry was applied to explore tryptophan metabolism between ESCC patients, metastatic ESCC patients (mESCC), and healthy controls. Statistical analysis on metabolite expression abundance and compound concentration ratio was conducted to discriminate patients from healthy controls. The concentration ratio of kynurenine, 5-hydroxytryptophan, 5-hydroxyindole-3-acetic acid, 5-hydroxytryptamine to their precursor tryptophan were identified as potential biomarkers, presenting high diagnostic capacity for distinguishing ESCC and mESCC patients from healthy controls. Moreover, a prognostic prediction model was also built on these ratios to distinguish metastasis patients from non-metastasis patients successfully. The high performance of ESCC prediction models suggest that concentration ratios of compounds may be used as biomarkers for early diagnosis and prognosis of the disease. In addition, concentration ratios of compounds show a progressively increased trend from non-metastasis to metastasis patients compared with healthy controls, which is in accordance with process of malignant transformation of ESCC. This interested finding suggests that disturbed tryptophan metabolism is correlated to progression and metastasis of ESCC since concentration ratios of compounds reflect activity of enzymes involved in tryptophan metabolism. This study reveals the impact of tryptophan metabolism to tumorigenesis and metastasis of ESCC, which help biologists investigate mechanism of the disease., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Background: Neuroendocrine tumours are slow growing tumours known to secrete a variety of vasoactive peptides which give rise to symptoms of the carcinoid syndrome. The diagnosis and monitoring of patients with neuroendocrine tumours is undertaken in many centres using 24 h urinary measurement of 5-hydroxyindoleacetic acid. However, 5-hydroxyindoleacetic acid can also be quantified in plasma and serum., Methods: We measured 5-hydroxyindoleacetic acid concentration in 134 paired EDTA plasma and urine samples from 108 patients with known neuroendocrine tumours and 26 healthy volunteers. We also compared 5-hydroxyindoleacetic acid concentrations in paired serum and plasma samples (n = 63), then analysed paired urine and serum samples (n = 97). Furthermore, we examined the impact of renal impairment on serum 5-hydroxyindoleacetic acid by analysing 5-hydroxyindoleacetic acid in patients without neuroendocrine tumours in different stages of chronic kidney disease, as indicated by the estimated glomerular filtration rate., Results: Plasma and urine 5-hydroxyindoleacetic acid had very similar diagnostic sensitivities and specificities, with areas under the curve on ROC analysis of 0.917 and 0.920, respectively. Serum and plasma 5-hydroxyindoleacetic acid values showed good correlation but serum results demonstrated a positive bias, indicating the necessity for different serum and plasma reference intervals. There was an inverse correlation between estimated glomerular filtration rate and serum 5-hydroxyindoleacetic acid concentration, with 5-hydroxyindoleacetic acid increasing once the estimated glomerular filtration rate falls below 60 mL/min/1.73 m(2)., Conclusion: The measurement of both serum and plasma 5-hydroxyindoleacetic acid can be used for the diagnosis and monitoring of patients with neuroendocrine tumours. Provided renal function is taken into consideration, either of these tests should be incorporated into standard practice as an alternative assay to urinary 5-hydroxyindoleacetic acid., (© The Author(s) 2015.)

Introduction: Serotonin (5-HT) is involved in the pathology of Alzheimer's disease (AD)., Objective: We aimed to measure 5-HT level in platelets in AD and explore its association with cerebrospinal fluid (CSF), AD biomarkers (amyloid-β 1-42 (Aβ42), total tau (t-tau), and phosphorylated tau (p-tau)), and clinical symptoms., Methods: 15 patients with AD and 20 patients with subjective cognitive impairment (SCI) were included. 5-HT metabolites were measured, in a specific fraction, using high performance liquid chromatography with electrochemical detection (HPLC-ECD)., Results: Significantly lower 5-HT concentrations were observed in AD patients compared to SCI patients both after normalization against total protein (p = 0.008) or platelet count (p = 0.019). SCI patients with lower 5-HT level have higher AD CSF biomarkers, total tau (p = 0.026) and tau/Aβ42 ratio (p = 0.001), compared to those with high 5-HT levels., Conclusion: AD patients have reduced platelet 5-HT levels. In SCI, lower 5-HT content was associated with a higher AD-CSF biomarker burden.

Aim: To study differences in the visceral sensitivity of the colonic mucosa between patients with diarrhea-predominant irritable bowel syndrome (IBS-D) and those with ulcerative colitis (UC) in remission and to relate these differences with changes in the 5-hydroxytryptophan (5-HT) signaling pathway., Methods: Gastrointestinal symptoms were used to determine the clinical symptom scores and rectal visceral sensitivity of patients with IBS-D and patients with UC in remission. Blood levels of 5-HT and 5-hydroxyindoleacetic acid (5-HIAA) were measured using an HPLC-electrochemical detection system. The levels of 5-HT 3 receptor (3R), 4R, and 7R mRNAs in colonic biopsy samples were detected using reverse transcription-polymerase chain reaction. The protein expression of TPH1 was analyzed by Western blot and immunohistochemistry., Results: Abdominal pain or discomfort, stool frequency, and the scores of these symptoms in combination with gastrointestinal symptoms were higher in the IBS-D and UC groups than in the control groups. However, no significant differences were observed between the IBS-D and UC remission groups. With respect to rectal visceral sensitivity, the UC remission and IBS-D groups showed a decrease in the initial perception threshold, defecating threshold and pain threshold. However, these groups exhibited significantly increased anorectal relaxation pressure. Tests examining the main indicators of the 5-HT signaling pathway showed that the plasma 5-HT levels, 5-HIAA concentrations, TPH1 expression in the colonic mucosa, and 5-HT3R and 5-HT5R expression were increased in both the IBS-D and the UC remission groups; no increases were observed with respect to 5-HT7R expression., Conclusion: The IBS-D and UC groups showed similar clinical symptom scores, visceral sensitivity, and levels of serotonin signaling pathway indicators in the plasma and colonic mucosa. However, the pain threshold and 5-HT7R expression in the colonic mucosa were significantly different between these groups. The results reveal that (1) IBS-D and UC are related to visceral sensitivity pathogenesis and the clinical manifestations of these conditions and (2) the observed differences in visceral hypersensitivity are possibly due to differences in levels of the 5-HT7 receptor, a component of the 5-HT signaling pathway.

Although lower extremity arterial disease is frequently accompanied by diabetes mellitus, the association of circulating biomarkers with flow components during the cardiac cycle in lower-leg arteries has yet to be fully elucidated. We enrolled 165 type 2 diabetic patients with normal ankle-brachial index (ABI 1.0-1.4), comprising 106 normoalbuminuric and 59 microalbuminuric patients, and 40 age-matched nondiabetic subjects consecutively admitted to our hospital. Serum high sensitivity C-reactive protein (hsCRP) level and plasma von Willebrand factor ristocetin cofactor activity (VWF) and vasoconstrictor serotonin metabolite 5-hydroxyindole acetic acid (5-HIAA) concentrations were measured. An automatic device was used to measure ABI and brachial-ankle pulse wave velocity (baPWV). Flow components during the cardiac cycle, total flow volume, and resistive index at popliteal artery were evaluated using gated magnetic resonance imaging. Although estimated glomerular filtration rate (eGFR), early diastolic flow reversal, heart rate, and ABI were similar between the groups, diabetic patients had higher log hsCRP (p<0.001), VWF (p<0.001), 5-HIAA (p=0.002), resistive index (p<0.001) and baPWV (p<0.001) and lower systolic (p=0.026) and late diastolic (p<0.001) forward flows and total flow volume (p<0.001) than nondiabetic subjects. Multivariate analyses demonstrated that 5-HIAA in microalbuminuric patients showed higher associations with systolic and late diastolic forward flows during the cardiac cycle, total flow volume and resistive index at popliteal artery, and eGFR compared to normoalbuminuric patients. In microalbuminuric patients, 5-HIAA was a significant independent determinant among these factors. Thus, increased plasma 5-HIAA levels are involved in the pathogenesis of impaired blood flow in lower extremities and renal insufficiency in diabetic patients with microalbuminuria.

Objectives: Women are at very high risk for the first onset of acute and severe mood disorders the first weeks after delivery. Tryptophan breakdown is increased as a physiological phenomenon of the postpartum period and might lead to vulnerability for affective psychosis (PP) and severe depression (PD). The aim of the current study was to investigate alterations in tryptophan breakdown in the physiological postpartum period compared to patients with severe postpartum mood disorders., Methods: We included 52 patients (29 with PP, 23 with PD), 52 matched healthy postpartum women and 29 healthy non-postpartum women. Analyzes of serum tryptophan metabolites were performed using LC-MS/MS system for tryptophan, kynurenine, 3-hydroxykynurenine, kynurenic acid and 5-hydroxyindoleacetic acid., Results: The first two months of the physiological postpartum period were characterized by low tryptophan levels, increased breakdown towards kynurenine and a downstream shift toward the 3-OH-kynurenine arm, away from the kynurenic acid arm. Kynurenine was significantly lower in patients with PP and PD as compared to healthy postpartum women (p=0.011 and p=0.001); the remaining tryptophan metabolites demonstrated few differences between patients and healthy postpartum women., Limitation: Low prevalence of the investigated disorders and strict exclusion criteria to obtain homogenous groups, resulted in relatively small sample sizes., Conclusion: The high kynurenine levels and increased tryptophan breakdown as a phenomenon of the physiological postpartum period was not present in patients with severe postpartum mood disorders. No differences were observed in the levels of the 'neurotoxic' 3-OH-kynurenine and the 'neuroprotective' kynurenic acid arms between patients and healthy postpartum women., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Background: To discover a novel antidepressant-like effect and anticonvulsant compound, seventeen new 2-oxo-3-phenyliminoindolin-1-Nphenylacetamide compounds were synthesized and screened for the antidepressant activity and anticonvulsant effects., Method: 2-oxo-3-phenyliminoindolin-1-N-phenylacetamide derivatives were synthesized with indoline-2, 3-dione as the starting material, through a nucleophilic substitution reaction and a nucleophilic addition-elimination reaction. The target derivatives 2a-2q were evaluated the antidepressant-like activity using the FST, TST, and evaluated anticonvulsant effect by MES test. The main monoamine neurotransmitters and their metabolites in mouse brain regions were also simultaneously determined by HPLC-ECD., Results: It was observed that 13 compounds showed significant reductions in the immobility time in the FST at a concentration of 50 mg/kg. Compound 2b was found to have the most potent antidepressant activity in the FST and the TST for 30 min after treatment. Compound 2b significantly increased the concentrations of the main neurotransmitters 5-HT, NE and the metabolite (5-HIAA, suggesting that the effects of compound 2b may be mediated through these neurotransmitters. As assessed using maximal electroshock, 13 compounds showed the anticonvulsant effects administered at the concentration levels of 100 or 300 mg/kg. Compound 2b showed anticonvulsant effect. Compound 2b could potentially be used as adjuncts of the antidepressants to treat depression in patients with epilepsy., Conclusion: In conclusion, compound 2b produced significant antidepressant-like activity and the mechanism of action may be due to increased 5-HT and NE in the mouse. Compound 2b showed more anticonvulsant effect. Compound 2b could potentially be used as adjuncts of the antidepressants to treat depression in patients with epilepsy.

The five-factor model of the Positive and Negative Syndrome Scale (PANSS) for schizophrenia symptoms is the most common multiple-factor model used in analyses; its use may improve evaluation of symptoms in schizophrenia patients. Plasma monoamine metabolite levels are possible indicators of clinical symptoms or response to antipsychotics in schizophrenia. We investigated the association between five-factor model components and plasma monoamine metabolites levels to explore the model's biological basis. Plasma levels of homovanillic acid (HVA), 3-methoxy-4-hydroxyphenylglycol (MHPG), and 5-hydroxyindoleacetic acid (5-HIAA) were measured using high-performance liquid chromatography in 65 Japanese patients with schizophrenia. Significant negative correlation between plasma 5-HIAA levels and the depression/anxiety component was found. Furthermore, significant positive correlation was found between plasma MHPG levels and the excitement component. Plasma HVA levels were not correlated with any five-factor model component. These results suggest that the five-factor model of the PANSS may have a biological basis, and may be useful for elucidating the psychopathology of schizophrenia. Assessment using the five-factor model may enable understanding of monoaminergic dysfunction, possibly allowing more appropriate medication selection. Further studies of a larger number of first-episode schizophrenia patients are needed to confirm and extend these results., (Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.)

Albiflorin (AF), separated from the root of Paeonia lactiflora Pall, possesses neuro-protective and anti-inflammatory activities. Based on previous results, our present research aims to investigate the antidepressant-like activity of AF in chronic unpredictable mild stress (CUMS)-induced rat model of depression. Eight weeks of CUMS process successfully established depression-like rat model, as evidenced by the enhanced immobility time in forced swimming test and the reduced sucrose preference, which were reversed to near normal by AF (20 mg/kg and 40 mg/kg) and fluoxetine (3 mg/kg; positive drug) treated. Compared to non-treated depression-like rats, the increased levels of 5-hydroxytryptamine (5-HT) and 5-hydroxyindoleacetic acid (5-HTAA) in serum and hypothalamus, and the reduced expressions of 5-HT1A receptor and 5-HT2A receptor in hypothalamus were observed after AF and fluoxetine oral administration indicating that AF-mediated antidepressant-like effect may be related to the normalization of serotonergic system. Additionally, four-week AF treated rats significantly showed improvement in the reduced dopamine and noradrenalin concentration in serum and hypothalamus as observed on depression-like rats. Altered levels of tyrosine hydroxylase, dopamine D2 receptor and dopamine transporter in hypothalamus reverted to the normal level after treatment with both AF and fluoxetine. All these data demonstrate that not only serotonergic system, but also dopaminergic system is involved in AF-mediated antidepressant-like effect in CUMS-induced rat model of depression., (Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.)

Neuroendocrine neoplasmas are a form of cancer arising from cells of diffuse neuroendocrine system. They produce peptides or amines that act as hormones or neurotransmitters. Incidence of NENs is relatively low. Diagnostic work-up and treatment requires a multidisciplinary team approach. The aim of this study was an analysis of data from patients with well-differentiated neuroendocrine neoplasmas of gastrointestinal tract. The study included patients followed up from 1998 to 2013 with histologically confirmed well-differentiated digestive neuroendocrine neoplasm with low or intermediate malignant potential. 97 patients were included; 34 men (35.1%) and 63 women (64.9%). In patients being diagnosed after 2005 interferon treatment is significantly less used than endoscopic and peptide receptor radionuclide therapy. We have identified more appropriate discriminant values of 5-HIAA and chromogranin A (6.8 mg/24 hours; 70 ng/ml) for predicting the presence of metastases at the time of diagnosis. We have identified following risk factors for overall mortality: liver metastases, presence of diarrhea, flush, small bowel primary tumor, high values of CgA and 5-HIAA at the time of diagnosis (5-HIAA > 520.52 mg/24 hours, CgA > 174.5 ng/ml). Surgical treatment was found to be a positive prognostic factor.

Allopurinol is a xanthine oxidase enzyme inhibitor that is widely used for the treatment of hyperuricemia and gout. The activity of tryptophan 2,3-dioxygenase, which metabolizes tryptophan (TRP), is decreased by xanthine oxidase inhibitors, causing TRP levels in the body to be increased. Increases in TRP levels in the brain might have antidepressant effects. The purpose of this study is to evaluate the antidepressant effects of allopurinol compared to those of fluoxetine, which is a proven antidepressant. Thirty-two Wistar albino male rats were divided into four groups (control, 10mg/kg fluoxetine, 50mg/kg allopurinol, 50mg/kg allopurinol+10 mg/kg fluoxetine; n=8 per group), and forced swimming tests were performed before and after 14days of drug administration. Serotonin, 5-hydroxyindolacetic acid and uric acid levels were measured in blood samples after the final treatment. When allopurinol and fluoxetine were administered separately, a decrease in the duration of immobility and an increased duration of swimming were observed in the forced swimming test. The results showed similar antidepressant efficacies between allopurinol and fluoxetine. However, we found no statistically significant difference in the antidepressant effect of the combined therapy versus single drug therapy., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Background: Accumulating evidence suggests that serotonergic system may be implicated in the pathophysiology of Parkinson's disease (PD), and particularly in nonmotor symptoms such as depression, fatigue, sleep disorders, sensory and autonomic dysfunction. This study aimed to evaluate plasma levels of serotonin (5-HT) and its metabolite 5-hydroxyindoleacetic acid (5-HIAA) in PD patients, and investigate their associations with nonmotor symptoms., Methods: Eighty-two PD patients and sixty-four controls underwent a series of clinical assessments, including Hamilton Depression Scale, Fatigue Severity Scale, Pittsburgh Sleep Quality Index, Visual Analog Scale for Pain, and Scale for Outcomes in PD for Autonomic Symptoms. Plasma 5-HT and 5-HIAA levels were measured by HPLC-ECD., Results: PD patients exhibited worse performance on nonmotor symptom scales (all P-values <0.001) and presented lower plasma levels of 5-HT (P < 0.001) and 5-HIAA (P < 0.001) than control individuals. Within the PD group, decreased concentrations of plasma 5-HT and 5-HIAA were correlated with more severe depression (r = -0.447, P < 0.001; r = -0.407, P < 0.001, respectively) and pain (r = -0.485, P < 0.001; r = -0.416, P < 0.001, respectively). After performing multiple linear regression, plasma 5-HT (P = 0.01) and 5-HIAA (P = 0.006) remained significantly associated with depression., Conclusions: Our results suggest that serotonergic dysfunction might exist in PD, and specifically correlated with depression and pain in PD. Plasma levels of 5-HT and 5-HIAA may be considered as peripheral markers for depression in PD., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Introduction: Dietary serotonin increases urinary secretion of 5-HIAA. A falsely elevated 5-HIAA may lead to incorrect suspicion of a neuroendocrine tumour. Therefore, we determined the effect and duration of dietary serotonin on serum 5-HIAA concentration. We also studied the distribution of 5-HIAA in serum fractions., Methods: We used serum samples from healthy volunteers (31 women and four men). All test subjects avoided serotonin-containing foods for three days before sample collection. They then ate either pineapple, banana, kiwi fruit, tomato or walnuts and additional blood samples were taken after 2, 4, 6, 24, 48 and 72 h. To study the distribution of 5-HIAA in serum, samples from a healthy individual, a test person who had ingested walnuts, and from a neuroendocrine tumour patient were fractionated by gel filtration chromatography. The fractions were analysed for 5-HIAA., Results: Serum 5-HIAA concentration increased significantly (P ≤ 0.001) within 2 h after ingestion of serotonin-containing food. After 2 h, 5-HIAA concentration started to decrease and reached the baseline concentration within 24 h. A calculated half-life of 5-HIAA in circulation was 1.3 h. In fractionated serum, 5-HIAA was found not only in free form but also in the albumin and α2-globulin fractions., Conclusions: The increase of serum 5-HIAA caused by dietary serotonin is significant but transient. Therefore, serotonin-containing foods should be avoided for one day before blood sampling. In serum, 5-HIAA is free and apparently bound to albumin. Minor amounts were also found in the α2-globulin fraction. Our liquid chromatography tandem mass spectrometry assay measures free 5-HIAA in serum., (© The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.)

Objective: The constellation of metabolic abnormalities seen in metabolic syndrome (MetS) has been linked to atherosclerosis and adverse cardiovascular outcomes due to heightened inflammation. Accumulating evidence suggests that peripheral 5-hydroxyindole-3-acetic acid (5-HIAA), the derivative end-product of serotonin (5-HT), might be involved in the pathogenesis of obesity, and abnormal lipid and glucose metabolism. We examined the association between serum 5-HIAA concentrations and MetS and also highly sensitive C-reactive protein (hsCRP)., Methods: We assessed 180 healthy adults (110 males and 70 females) in a cross-sectional setting. Anthropometric indices and blood pressure were measured, as were laboratory parameters including fasting 5-HIAA concentrations. The associations between 5-HIAA and individual components of MetS, as well as MetS as a single entity, were investigated with bivariate correlation and logistic regression analyses., Results: Eighty-nine individuals (49.4%) were diagnosed with MetS. Significant correlations were found between 5-HIAA concentrations and age (r = 0.184), waist circumference (r = 0.415), high-density lipoprotein (HDL) cholesterol (r = -0.148), systolic blood pressure (r = 0.374), diastolic blood pressure (r = 0.355), homeostasis model assessment of insulin resistance (r = 0.201), and hsCRP (r = 0.453) were found (P<.05 in all tests). In logistic regression, 5-HIAA was significantly associated with 4 MetS components including central obesity, raised triglycerides, raised blood pressure, and raised fasting plasma glucose (FPG) (P<.05). Moreover, 5-HIAA was a predictor of MetS as a single entity, and the relationship persisted after adjusting for hsCRP (odds ratio [OR] = 4.41, 95% confidence interval [CI]: 2.58-7.67, P<.001)., Conclusion: Elevated concentrations of 5-HIAA are seen in individuals with MetS. Increased 5-HIAA is also associated with hsCRP, a marker of chronic low-grade inflammation underlying MetS.

Depression is one of the most common mental disorders and a primary cause of disability. To better treat patients suffering this illness, elucidation of the underlying psychopathological and neurobiological mechanisms is urgently needed. Based on the above-mentioned evidence, we sought to investigate the effects of neuropeptide Y (NPY) treatment in tricyclic antidepressant treatment-resistant depression induced by adrenocorticotropic hormone (ACTH) administration. Mice were treated with NPY (5.84, 11.7 or 23.4mmol/μl) intracerebroventricularly (i.c.v.) for one or five days. The levels of serum corticosterone, tryptophan (TRP), kynurenine (KYN), serotonin (5-HT), 5-hydroxyindoleacetic acid (5-HIAA), brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF) and indoleamine 2,3-dioxygenase (IDO) activity in the hippocampus were analyzed. The behavioral parameters (depressive-like and locomotor activity) were also verified. This study demonstrated that ACTH administration increased serum corticosterone levels, KYN, 5-HIAA levels, IDO activity (hippocampus), immobility in the forced swimming test (FST) and the latency to feed in the novelty suppressed feeding test (NSFT). In addition, ACTH administration decreased the BDNF and NGF levels in the hippocampus of mice. NPY treatment was effective in preventing these hormonal, neurochemical and behavioral alterations. It is suggested that the main target of NPY is the modulation of corticosterone and neuronal plasticity protein levels, which may be closely linked with pharmacological action in a model of tricyclic antidepressant treatment-resistant depression. Thus, this study demonstrated a protective effect of NPY on the alterations induced by ACTH administration in mice, indicating that it could be useful as a therapy for the treatment of tricyclic antidepressant treatment-resistant depression., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Monoamine acidic metabolites in biological samples are essential biomarkers for the diagnosis of neurological disorders. In this work, acrylamide-functionalized graphene adsorbent was successfully synthesized by a chemical functionalization method and was packed in a homemade polyether ether ketone micro column as a micro-solid-phase extraction unit. This micro-solid-phase extraction unit was directly coupled to high-performance liquid chromatography to form an online system for the separation and analysis of three monoamine acidic metabolites including homovanillic acid, 5-hydroxyindole-3-acetic acid, and 3,4-dihydroxyphenylacetic acid in human urine and plasma. The online system showed high stability, permeability, and adsorption capacity toward target metabolites. The saturated extraction amount of this online system was 213.1, 107.0, and 153.4 ng for homovanillic acid, 5-hydroxyindole-3-acetic acid, and 3,4-dihydroxyphenylacetic acid, respectively. Excellent detection limits were achieved in the range of 0.08-0.25 μg/L with good linearity and reproducibility. It was interesting that three targets in urine and plasma could be actually quantified to be 0.94-3.93 μg/L in plasma and 7.15-19.38 μg/L in urine. Good recoveries were achieved as 84.8-101.4% for urine and 77.8-95.1% for plasma with the intra- and interday relative standard deviations less than 9.3 and 10.3%, respectively. This method shows great potential for online analysis of trace monoamine acidic metabolites in biological samples., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Peripheral serotonin (5-HT) has been involved in adverse cardiac remodeling and valve fibrosis. The peripheral levels of 5-HT mainly depend on its release from activated platelets and degradation by monoamine oxidase A (MAO-A). The SERAOPI study investigated the relationship between arterial serotoninergic system, degree of platelet activation and cardiac remodeling, in patients with aortic valve stenosis (AS). Thirty patients with severe AS and 15 control subjects underwent transthoracic echocardiography, radial, and aortic arterial blood sampling. Measurements of 5-HT and its MAO-A-dependent degradation product, 5-HIAA, were performed by HPLC. Arterial platelet activation was assessed by flow cytometry analysis of platelet surface expression of P-selectin and activated integrin GPIIb/IIIa. Activated platelets and arterial plasma 5-HT increased in AS patients as compared to control subjects (P-selectin 1.08 ± 0.2MFI vs. 0.49 ± 0.1MFI, P = 0.04; GPIIb/IIIa 0.71 ± 0.1MFI vs. 0.35 ± 0.1MFI; P = 0.0015 and arterial plasma 5-HT 11.55 ± 1.6 nM vs. 6.18 ± 0.7 nM, P = 0.028, respectively). Moreover, 5-HT was strongly correlated to left ventricular hypertrophy assessed by echocardiography. The correlation was independent of cardiovascular risk comorbidities and others echocardiographic AS parameters. Finally, plasma 5-HIAA increased in AS patients (74.64 ± 9.7 nM vs. 37.16 ± 4.1 nM; P = 0.0002) indicating a higher 5-HT degradation rate by MAO-A. Platelet activation, arterial circulating serotonin, and serotonin degradation increased in patients with AS. These observations suggest that the serotoninergic system may contribute to the pathogenesis of AS including valve fibrosis and adverse ventricular remodeling., (© 2014 Wiley Periodicals, Inc.)

Background: Activation of glutamate (Glu) receptors plays a key role in the pathophysiology of migraine. Both NMDA and metabotropic Glu receptors are activated or inhibited by metabolites of the kynurenine pathway, such as kynureninic acid (KYNA), quinolinic acid (QUINA), and xanthurenic acid (XA). In spite of the extensive research carried out on KYNA and other kynurenine metabolites in experimental models of migraine, no studies have ever been carried out in humans. Here, we measured all metabolites of the kynurenine pathway in the serum of patients affected by chronic migraine (CM) and age- and gender-matched healthy controls., Methods: We assessed serum levels of tryptophan (Trp), L-kynurenine (KYN), KYNA, anthranilic acid (ANA), 3-hydroxyanthranilic acid (3-HANA), 3-hydroxykynirenine (3-HK), XA, QUINA, and 5-hydroxyindolacetic acid (5-HIAA) in 119 patients affected by CM (ICHD-3beta criteria) and 84 age-matched healthy subjects. Patients with psychiatric co-morbidities, systemic inflammatory, endocrine or neurological disorders, and mental retardation were excluded. Serum levels of all metabolites were assayed using liquid chromatography/tandem mass spectrometry (LC-MS/MS)., Results: LC-MS/MS analysis of kynurenine metabolites showed significant reductions in the levels of KYN (-32 %), KYNA (-25 %), 3-HK (-49 %), 3-HANA (-63 %), 5-HIAA (-36 %) and QUINA (-80 %) in the serum of the CM patients, as compared to healthy controls. Conversely, levels of Trp, ANA and XA were significantly increased in CM patients (+5 %, +339 % and +28 %, respectively)., Conclusions: These findings suggest that in migraine KYN is unidirectionally metabolized into ANA at expenses of KYNA and 3-HK. The reduction in the levels of KYNA, which behaves as a competitive antagonist of the glycine site of NMDA receptors, is consistent with the hypothesis that NMDA receptors are overactive in migraine. The increase in XA, a putative activator of Glu2 receptors, may represent a compensatory event aimed at reinforcing endogenous analgesic mechanisms. The large increase in the levels of ANA encourages research aimed at establishing whether ANA has any role in the regulation of nociceptive transmission.

Background: The reported efficacy of memantine in the treatment of patients with cluster headache (CH) suggests that NMDA receptors are involved in mechanisms of nociceptive sensitization within the trigeminal system associated with CH. NMDA receptors are activated or inhibited by neuroactive compounds generated by tryptophan metabolism through the kynurenine pathway. In the accompanying manuscript, we have found that serum levels of all kynurenine metabolites are altered in patients with chronic migraine. Here, we have extended the study to patients affected by episodic or chronic CH as compared to healthy controls., Method: We assessed serum levels of kynurenine (KYN), kynurenic Acid (KYNA), anthranilic acid (ANA), 3-hydroxy-anthranilic acid (3-HANA), 3-hydroxykynurenine (3-HK), xanthurenic acid (XA), quinolinic acid (QUINA), tryptophan (Trp) and 5-hydroxyindolacetic acid (5-HIAA) by means of a liquid chromatography/tandem mass spectrometry (LC/MS-MS) method in 21 patients affected by CH (15 with episodic and 6 with chronic CH), and 35 age-matched healthy subjects. Patients with psychiatric co-morbidities, systemic inflammatory, endocrine or neurological disorders, and mental retardation were excluded., Results: LC/MS-MS analysis of kynurenine metabolites showed significant reductions in the levels of KYN (-36 %), KYNA (-34 %), 3-HK (-51 %), 3-HANA (-54 %), XA (-25 %), 5-HIAA (-39 %) and QUINA (-43 %) in the serum of the overall population of patients affected by CH, as compared to healthy controls. Serum levels of Trp and ANA were instead significantly increased in CH patients (+18 % and +54 %, respectively). There was no difference in levels of any metabolite between patients affected by episodic and chronic CH, with the exception of KYN levels, which were higher in patients with chronic CH., Conclusion: The reduced levels of KYNA (an NMDA receptor antagonist) support the hypothesis that NMDA receptors are overactive in CH. A similar reduction in KYNA levels was shown in the accompanying manuscript in patients affected by chronic migraine. The reduced levels of XA, a putative analgesic compound, may contribute to explain the severity of pain attacks in CH. These data, associated with the data reported in the accompanying manuscript, supports a role for the kynurenine pathway in the pathophysiology of chronic headache disorders.