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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.)

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.)

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.

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.

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.

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.

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.)

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.

Purpose: Metastatic neuroendocrine tumors secrete serotonin and other vasoactive substances that are responsible for carcinoid syndrome and carcinoid heart disease. We sought to evaluate the discriminatory utility of diagnostic biomarkers in determining the presence and severity of carcinoid heart disease in patients with metastatic neuroendocrine tumors., Patients and Methods: A cross-sectional study of patients with neuroendocrine tumors with documented liver metastases and/or carcinoid syndrome between April 2009-October 2012 in 5 tertiary referral centers. Serum was analyzed for Chromogranin A, Chromogranin B and N-terminal pro Brain Natriuretic Peptide (NT-proBNP). Plasma was analyzed for Neurokinin A and 5-Hydroxyindoleacetic acid (5HIAA). Echocardiography was used to determine the presence and severity of carcinoid heart disease. Non-parametric receiver operating characteristic curves were constructed for biomarkers, and the area under the curve determined. The severity of cardiac involvement was correlated with the concentration of each biomarker., Results: A total of 187 patients were identified of whom 37 (20%) had carcinoid heart disease. Significantly higher median values of all biomarkers were found in the patients with cardiac involvement. NT-proBNP and plasma 5HIAA had the highest areas under the curve for the prediction of carcinoid heart disease [NT-proBNP 0.82 (95% confidence interval 0.74-0.90, p<0.0001) and 5HIAA 0.85 (95% confidence interval 0.78-0.92, p<0.0001]. NT-proBNP was moderately correlated (r = 0.48, p<0.001) whereas plasma 5HIAA was only weakly correlated (r = 0.34, p<0.001) with the echocardiographic severity score., Conclusion: NT-proBNP and plasma 5HIAA are both sensitive and specific biomarkers for the presence of carcinoid heart disease whereas only NT-proBNP is moderately correlated with disease severity.

A high performance liquid chromatography-ultraviolet/fluorescence detection (HPLC-UV/FLD) with on-column derivatization was established to simultaneously determine tryptophan (Trp), kynurenine (Kyn), 5-hydroxyindole acetic acid (5-Hiaa) and kynurenic acid (Kyna). A Hypersil C-18 column (250 mm x 4.0 mm, 5 microm) was used for the analysis at 30 degrees C. The separation was carried out with the mobile phase consisting of 250 mmol/L zinc acetate (pH 5.5) and acetonitrile (95: 5, v/v) at a flow rate of 0.8 mL/min using 3-nitrotyrosine as internal standard (IS). The excitation (Ex) and emission (Em) wavelengths were set at 278 nm (lambda(ex))/343 nm (lambda(em)) for 5-Hiaa and 244 nm (lambda(ex))/400 nm (lambda(em)) for Kyna, while the wavelengths of ultraviolet detection were set at 360 nm for Kyn and IS, 302 nm for Trp. The recoveries were in the range of 91.62% to 114.17%. The linearities were from 2.50 micromol/L to 320.00 micromol/L for Trp, 0.32 micromol/L to 15.36 micromol/L for Kyn, 3.27 nmol/L to 104.60 nmol/L for 5-Hiaa, and 14.00 nmol/L to 464.80 nmol/L for Kyna. The detection limits were 0.078 micromol/L, 0.056 micromol/L, 0.690 nmol/L and 1.290 nmol/L for Trp, Kyn, 5-Hiaa, and Kyna, respectively. Thirty plasma samples of normal pregnant women and 28 plasma samples of healthy controls were tested, and the results exhibited that the concentrations of Trp, Kyn and Kyna in the plasma of the normal pregnant women were significantly different from those of the control group (all P < 0.01). The method is simple and sensitive with good reproducibility, and it is suitable for clinical measurements.

Background: The role of plasma monoamines in patients with chronic obstructive pulmonary disease (COPD) with depression is unclear. To investigate monoamines in 20 depressed patients with COPD, the plasma concentrations of serotonin, 5-hydroxyindoleacetic acid (5-HIAA), homovanillic acid, and 3-methoxy-4-hydroxyphenylglycol (MHPG) were measured and compared with those in 50 non-depressed COPD patients, and also with 23 age- and gender-matched non-smokers and 13 smokers as non-depressed healthy controls., Methods: Diagnosis of depression was assessed using the Centre for Epidemiologic Studies Depression Scale. Plasma concentrations of monoamines were measured by high-performance liquid chromatography., Results: None of the depressed COPD patients had suicidal ideation. The plasma 5-HIAA level [median, (25% and 75% quartiles)] in depressed COPD patients [6.8 ng/mL, (4.9 and 13.1)] was significantly higher than in non-depressed COPD patients [5.4, (4.2 and 7.5)] (p=0.022) and non-smokers [5.1 (3.8 and 7.2)] (p=0.041), but not smokers [4.7, (4.0 and 6.7)] (p>0.05). The plasma 5-HIAA level (r=0.24, p=0.049) was significantly associated with the severity of depression in patients with COPD. The plasma MHPG level was significantly higher in depressed COPD patients (p=0.043) than in smokers, but was not higher than that in non-depressed COPD patients or non-smokers, although the level of MHPG was not associated with the severity of depression., Conclusion: The plasma 5-HIAA level is increased in depressed COPD patients. Plasma monoamines may be a good biomarker for detection of depression in patients with COPD.

Background: Serotonin (5-hydroxytryptamine; 5-HT), a tryptophan metabolite, plays an important regulatory role in the human central nervous system and in the gastrointestinal tract. Acute tryptophan depletion (ATD) is currently the most widely established method to investigate 5-HT metabolism., Objective: The aim of this study was to assess the effect of an acute decrease in the systemic availability of tryptophan on intestinal 5-HT metabolism and permeability., Design: Thirty-three healthy volunteers (17 with ATD, 3 of whom dropped out; 16 placebo) participated in this randomized placebo-controlled study. Plasma and duodenal mucosal concentrations of 5-HT, 5-hydroxyindoleacetic acid (5-HIAA), and kynurenic acid (KA) were measured by HPLC-mass spectrometry. Intestinal barrier function was assessed with a multisugar plasma test, and analysis of tight junction transcription was performed in duodenal biopsy samples obtained by gastroduodenoscopy., Results: Mucosal 5-HT, 5-HIAA, and KA concentrations remained unaltered by ATD. In contrast, ATD significantly decreased plasma 5-HT (P < 0.05) and 5-HIAA (P < 0.0001) concentrations. After endoscopy, a significant increase in plasma 5-HT concentrations was observed in the placebo group (P = 0.029) compared with the ATD group. Moreover, a significant increase in plasma KA concentrations over time was found in the placebo group (P < 0.05). No changes in intestinal barrier function were observed., Conclusions: An acute decrease in precursor availability does not affect mucosal concentrations of serotonergic metabolites, in contrast with systemic concentrations. ATD alters biochemical responses to acute stress from the endoscopic examination reflected by lower 5-HT concentrations. Changes in 5-HT concentrations were paralleled by alterations in KA concentrations, which suggest competition between the 2 metabolic pathways for the mutual precursor. This trial was registered at clinicaltrials.gov as NCT00731003.

Objective: Serotonin mediates vasoconstriction and induces the activation of platelets, which may promote atherosclerosis. The aim of this study was to investigate whether plasma 5-hydroxyindole-3-acetic acid (5-HIAA; a derivative end product of serotonin) concentrations are high in subjects with metabolic syndrome (MetS) and to investigate the relationship between plasma 5-HIAA concentrations and clinical and biochemical metabolic parameters., Research Design and Methods: Plasma 5-HIAA concentrations were measured in 311 subjects (152 men and 159 women) recruited from the Oike Clinic, which provides regular health check-ups for employees. We evaluated the relationship between plasma 5-HIAA concentrations and clinical and biochemical metabolic parameters, including waist circumference, serum lipid concentrations, fasting plasma glucose, or blood pressure., Results: Plasma 5-HIAA concentrations were higher in subjects with MetS than in those without, in both men (6.5 ± 4.4 vs. 4.9 ± 1.3 ng/mL, P < 0.005) and women (7.9 ± 6.5 vs. 5.2 ± 1.6 ng/mL, P < 0.005). In men, fasting plasma glucose (r = 0.197, P = 0.0146) was positively correlated, whereas HDL cholesterol (r = -0.217, P = 0.0071) was negatively correlated, with logarithmic (log) (plasma 5-HIAA concentrations). In women, triglycerides (r = 0.252, P = 0.0013) and fasting plasma glucose (r = 0.344, P < 0.0001) were positively correlated, whereas HDL cholesterol (r = -0.328, P < 0.0001) was negatively correlated, with log (5-HIAA concentrations). Furthermore, log (plasma 5-HIAA concentrations) were higher in subjects with more components of MetS., Conclusions: Plasma 5-HIAA concentrations are high in subjects with MetS, suggesting the potential importance of serotonin in the development of cardiovascular disease in MetS.

Objective: To investigate psychological distress, serum levels of monoamine neurotransmitters and their metabolites, as well as their correlation with polycystic ovarian syndrome (PCOS)., Methods: Thirty infertility patients with PCOS were assigned as the experimental group and 30 infertility patients without PCOS were assigned as the control group. Psychological distress was self-evaluated in all patients with Symptom Checklist 90 (SCL-90). Serum concentrations of norepinephrine (NE) and its metabolite 3-methoxy-4-hydroxyphenylglycol (MHPG), 5-hydroxytryptamine (5-HT) and its metabolite 5-hydroxyindoleacetic acid (5-HIAA), dopamine (DA) and its metabolites homovanillic acid (HVA) and dihydroxy-phenyl acetic acid (DOPAC) were measured by high-performance liquid chromatography., Results: The anxious and depressive subscales of SCL-90 were significantly higher in infertility patients with PCOS than those without PCOS (p < 0.05). The serum concentrations of 5-HT, 5-HIAA and HVA were significantly lower in infertility patients with PCOS than those without PCOS (p < 0.05). Importantly, the phobia subscale scores of SCL-90 positively correlated with serum MHPG level (p < 0.05), while the hostility subscale's scores negatively correlated with serum DOPAC level (p < 0.05)., Conclusion: Psychological and neurological factors play a crucial role in PCOS.

Background: Amyotrophic lateral sclerosis (ALS) is a life-threatening neurodegenerative disease involving upper and lower motor neurons loss. Clinical features are highly variable among patients and there are currently few known disease-modifying factors underlying this heterogeneity. Serotonin is involved in a range of functions altered in ALS, including motor neuron excitability and energy metabolism. However, whether serotoninergic activity represents a disease modifier of ALS natural history remains unknown., Methodology: Platelet and plasma unconjugated concentrations of serotonin and plasma 5-HIAA, the major serotonin metabolite, levels were measured using HPLC with coulometric detection in a cohort of 85 patients with ALS all followed-up until death and compared to a control group of 29 subjects., Principal Findings: Platelet serotonin levels were significantly decreased in ALS patients. Platelet serotonin levels did not correlate with disease duration but were positively correlated with survival of the patients. Univariate Cox model analysis showed a 57% decreased risk of death for patients with platelet serotonin levels in the normal range relative to patients with abnormally low platelet serotonin (p = 0.0195). This protective effect remained significant after adjustment with age, gender or site of onset in multivariate analysis. Plasma unconjugated serotonin and 5-HIAA levels were unchanged in ALS patients compared to controls and did not correlate with clinical parameters., Conclusions/significance: The positive correlation between platelet serotonin levels and survival strongly suggests that serotonin influences the course of ALS disease.

Purpose: Carcinoid syndrome, characterized by flushing, diarrhea, and valvular heart disease, can occur following carcinoid tumor metastasis to the liver and systemic release of bioactive hormones into the systemic circulation. Treatment of this devastating disease is hampered by the lack of an in vivo model that recapitulates the clinical syndrome., Experimental Design: Here, we have injected BON cells, a novel human carcinoid cell line established in our laboratory, into the spleens of athymic nude mice to establish liver metastases., Results: The majority of mice injected intrasplenically with BON cells developed significant increases in plasma serotonin and urine 5-hydroxyindoleacetic acid, and several mice exhibited mesenteric fibrosis, diarrhea, and fibrotic cardiac valvular disease reminiscent of carcinoid syndrome by both echocardiographic and histopathologic evaluation. Mice pretreated with octreotide, a long-acting somatostatin analogue, or bevacizumab, a vascular endothelial growth factor inhibitor, developed fewer liver metastases and manifestations of carcinoid syndrome, including valvular heart disease., Conclusion: We have provided an important in vivo model to further delineate novel treatment modalities for carcinoid syndrome that will also be useful to elucidate the factors contributing to the sequelae of carcinoid disease (e.g., mesenteric fibrosis and valvular heart disease).

Purpose: To develop a population pharmacokinetic-pharmacodynamic (PK-PD) model that defines the dose-concentration-effect relationship of 5,6-dimethylxanthenone-4-acetic acid (DMXAA), using plasma 5-hydroxyindole-3-acetic acid (5-HIAA) as a biomarker for the antivascular effect of DMXAA., Experimental Design: The plasma DMXAA and 5-HIAA concentration data were obtained from 124 patients receiving DMXAA monotherapy as a 20-minute i.v. infusion weekly or every 3 weeks at doses of 6 to 4,900 mg/m(2). The PK and PD data were analyzed by nonlinear mixed effects modeling with NONMEM version 5., Results: DMXAA concentration-time profiles were well described by a three-compartment model with saturable elimination (Michaelis-Menten kinetics). Body surface area (BSA) and sex were significant covariates on the volume of distribution of the central compartment (V(1)) and the maximum elimination rate (V(m)), respectively. Population estimates for V(m), K(m) (concentration at which half V(m) is achieved), and V(1) were 112[1 + 0.474(2-sex)] micromol/L/h, 102 micromol/L, and 8.19(BSA/1.8)(0.857) liters, respectively (sex in V(m) is equal to 1 for males and equal to 2 for females). The effect of DMXAA on plasma 5-HIAA was described by the stimulatory E(max) model, where population estimates for baseline, E(max), and EC(50) were 46.3 micromol/L, 2.62-fold increase of the baseline value, and 631 micromol/L, respectively., Conclusions: DMXAA plasma disposition is characterized by a saturable elimination process. BSA-guided dosing is important. The present PK-PD model, with 5-HIAA as a biomarker, supports the use of DMXAA doses of 1,000 to 2,000 mg/m(2) in phase II studies, and provides an example of how PK-PD models can be used to aid in selection of drug doses for phase II evaluation.

One intrinsic abnormality of pulmonary artery smooth muscle cells (PA-SMCs) in human idiopathic pulmonary hypertension (iPH) is an exaggerated proliferative response to internalized serotonin (5-HT) caused by increased expression of the 5-HT transporter (5-HTT). To investigate whether 5-HTT overexpression in PA-SMCs is sufficient to produce PH, we generated transgenic mice overexpressing 5-HTT under the control of the SM22 promoter. Studies in SM22-LacZ(+) mice showed that the transgene was expressed predominantly in SMCs of pulmonary and systemic vessels. Compared with wild-type mice, SM22-5-HTT(+) mice exhibited a 3- to 4-fold increase in lung 5-HTT mRNA and protein, together with increased lung 5-HT uptake activity, but no changes in platelet 5-HTT activity or blood 5-HT levels. At 8 weeks of age, SM22-5-HTT(+) mice exhibited PH, with marked increases in right ventricular systolic pressure (RVSP), right ventricle/left ventricle+septum ratio, and muscularization of distal pulmonary vessels, but no changes in systemic arterial pressure. PH worsened with age. Except a marked decrease in Kv channels, no changes in the lung expression of mediators of pulmonary vascular remodeling were observed in SM22-5-HTT(+) mice. Compared with wild-type mice, SM22-5-HTT(+) mice showed depressed hypoxic pulmonary vasoconstriction contrasting with greater severity of hypoxia- or monocrotaline-induced PH. These results show that increased 5-HTT expression in PA-SMCs, to a level close to that found in human iPH, lead to PH in mice. They further support a central role for 5-HTT in the pathogenesis of PH, making 5-HTT a potential therapeutic target.

Background: Serotonin (5-hydroxytryptamine; 5-HT) overproduction is responsible for cardiac valvular disease in patients with carcinoid tumors. Reduced 5-HT inactivation is one proposed mechanism of the valvulopathy observed in individuals treated with the appetite suppressants fenfluramine and phentermine. One key protein limiting systemic availability of 5-HT is the 5-HT transporter (5-HTT) expressed by platelets and pulmonary vascular cells; 5-HTT is responsible for 5-HT uptake and subsequent inactivation of the amine passing through the lung. Here we investigated whether 5-HTT-deficient (5-HTT-KO) mice developed structural and/or functional cardiac abnormalities and valvulopathy., Methods and Results: Cardiac endothelial cells expressed large amounts of 5-HTT in wild-type mice. 5-HTT deficiency appeared to be associated with marked interstitial, perivascular, and valvular fibrosis as evidenced by staining of cardiac collagen in 5-HTT-KO mice. Histological analysis provided evidence for valvulopathy characterized by valvular hyperplasia and prominent fibrosis at the attachment site and base of the leaflets. Echocardiography revealed an increase in left ventricular lumen diameter and a decrease in left ventricular diameter fractional shortening. Although 5-HT1B receptors mediated the 5-HT-induced collagen secretion by human cardiac myofibroblasts, the contribution of this receptor type to valvulopathy was ruled out because double-KO mice deficient in both 5-HTT and 5-HT1B receptors showed the same cardiac alterations as 5-HTT-KO mice., Conclusions: The present results establish a link between 5-HTT and the development of cardiac fibrosis and valvulopathy in vivo. 5-HTT-KO mice represent an especially relevant model for studying the mechanisms by which 5-HT induces valvulopathy.

Background & Aims: Evidence suggests that postprandial platelet-depleted plasma 5-hydroxytryptamine (5-HT) concentrations may be abnormal in irritable bowel syndrome (IBS). However, interpretation of the data has been hampered by the variable methodology and rather small numbers used in previous studies. Therefore, the aim of this study was to measure concentrations of platelet-depleted plasma 5-HT and its metabolite 5-HIAA under fasting and fed conditions in a large group of patients with diarrhea-predominant (d-) and constipation-predominant (c-) IBS, compared with controls. The ratio of plasma 5-HIAA:5-HT and platelet stores was also assessed., Methods: Twenty-nine c-IBS patients (aged, 19-53 years), 55 d-IBS patients (aged, 19-52 years), and 35 healthy volunteers (aged, 18-46 years) had platelet-depleted plasma 5-HT/5-HIAA concentrations measured using reverse-phase, high-performance liquid chromatography with fluorimetric detection before and after a standard meal., Results: d-IBS patients had raised platelet-depleted plasma 5-HT concentrations under fasting and fed conditions (P < .05). However, the postprandial relative to fasting concentration was similar to controls. In contrast, c-IBS patients failed to show an increase in platelet-depleted plasma 5-HT concentration with meal ingestion compared with controls (P < .01). c-IBS was associated with decreased 5-HIAA (P < .01) but normal 5-HIAA:5-HT ratio and d-IBS with normal 5-HIAA concentrations but reduced 5-HIAA:5-HT ratio (P < .005). C-IBS but not d-IBS patients had increased platelet 5-HT., Conclusions: These results support the concept that d-IBS is characterized by reduced 5-HT reuptake, whereas impaired release may be a feature of c-IBS. These results also provide a rational basis for current pharmacologic approaches involving modulation of different 5-HT receptors in c- and d-IBS.

A single institution prospective trial was conducted to evaluate the efficacy of biotherapy or chemotherapy in metastatic neuroendocrine carcinomas (NECs). The choice of therapy was based on the revised histological classification criteria of the WHO in an effort to define a standardized protocol for therapy of these cancers. Patients with well-differentiated NECs (WD-NECs; n=11) received therapy with octreotide long-acting release and interferon-alpha-2b for a maximum of 1 year; cases with poorly-differentiated NECs (PD-NECs; n=8) were given combination cisplatin, L-leucovorin and 5-fluorouracil chemotherapy for a maximum of 9 cycles. Five patients (4 with WD-NECs) had carcinoid syndrome. Among the patients with WD-NECs (median follow-up 20 months, range 4-40), 4 had partial responses and 7 had stable disease. In patients with PD-NECs (median follow-up 10.5 months, range 3-30), 3 had partial response, 2 stable disease, and the disease progressed in 3 cases. The 2-year survival rate in WD-NECs and PD-NECs was 88% and 66%, respectively. Grade 3-4 side-effects were limited to 9% thrombocytopenia and 12.5% neutropenia. Both these treatment regimens had a good therapeutic index and compared favourably with those previously reported for metastatic WD-NECs and PD-NECs.

Monoaminergic systems play a crucial role in linking behaviour and physiology. Here the physiological and behavioural effects of metal exposure in relation to monoaminergic systems were considered by exposing rainbow trout dyads, demonstrating stable dominance relationships, to cadmium or lead. Fish exposed to 4 microg l(-1) cadmium accumulated more cadmium at the gill than fish held in control water. Fish exposed to 7 microg l(-1) cadmium had higher gill, liver and kidney cadmium concentrations. No significant lead accumulation was seen after exposure to 46 microg l(-1) for 48 h but exposure to 325 microg l(-1) lead caused an increase in gill, liver and kidney lead concentrations. Brain accumulation of both cadmium and lead was only seen after exposure to the highest concentrations. Exposure to 4 or 7 microg l(-1) cadmium, or 46 or 325 microg l(-1) lead for 48 h did not disrupt established dominance hierarchies. As expected with this stable behavioural situation, in control pairs, animals of different social status displayed different physiological profiles. Subordinate fish had higher concentrations of circulating plasma cortisol and telencephalic 5-hydroxyindoleacetic acid/5-hydroxytryptamine (serotonin) (5-HIAA/5-HT) ratios. However, these physiological profiles were affected by metal exposure, with a trend towards higher serotonergic activity in dominant fish. Dominants exposed to 325 microg l(-1) lead had significantly higher hypothalamic 5-HIAA/5-HT ratios when compared with subordinates. The results demonstrate that if stable social hierarchies are established in control water they may not be affected by exposure to cadmium and lead although physiological changes may be evident.

Objective: Parietal cell antibodies (PCAs) are found in 20% of type 1 diabetic patients, denoting autoimmune gastritis and pernicious anemia, which may predispose to enterochromaffin-like (ECL) cell hyper/dysplasia and gastric carcinoid tumors. We evaluated whether chromogranin A (CgA), 5-hydroxyindole acetic acid (5-HIAA), and neuron-specific enolase (NSE) contribute to screening for ECL cell hyper/dysplasia., Research Design and Methods: Sera from 93 type 1 diabetic patients (53 men and 40 women, 31 PCA(+) and 62 PCA(-), aged 45 +/- 13 years) were analyzed for PCAs by indirect immunofluorescence and for CgA, NSE, and gastrin by radioimmunoassay. Urinary 5-HIAA was tested by high-performance liquid chromatography. Corpus atrophy and ECL cell proliferation were assessed in gastric biopsies., Results: PCA(+) patients had higher gastrin (P < 0.0001) and CgA levels (P = 0.003) and were more prone to autoimmune gastritis (odds ratio [OR] 17, P < 0.0001) and ECL cell hyper/dysplasia (OR = 23, P = 0.005) than PCA(-) subjects. ECL cell hyper/dysplasia was present in seven PCA(+) patients who showed higher CgA levels (P < 0.0001) than subjects without ECL cell hyper/dysplasia, but NSE and 5-HIAA levels were similar. CgA levels correlated with gastrinemia (r = 0.50, P < 0.0001), PCA titer (r = 0.42, P = 0.001), and 5-HIAA levels (r = 0.38, P = 0.012). Logistic regression identified the CgA level (beta = 0.01, P = 0.027) as an independent risk factor for ECL cell hyper/dysplasia when PCA, CgA, 5-HIAA, NSE, gastrin, sex, and age were tested. Multivariate linear regression demonstrated that CgA level was determined by ECL cell density (r = 0.59, P < 0.0001) and gastrin level (r = 0.67, P = 0.02). One PCA(+) patient with elevated gastrin, CgA, and 5-HIAA levels had a gastric carcinoid tumor., Conclusions: PCA(+) patients, particularly those with high gastrin and CgA levels, risk developing ECL cell hyper/dysplasia. The determination of CgA, but not NSE and 5-HIAA, may complement histology in evaluating ECL cell mass.

The monoamine and intracellular calcium systems are two major elements of nervous system functions. However, their role in human brain development is unclear. We studied the association between activity of monoamine and intracellular calcium systems during prenatal life and subsequent psychomotor performances in healthy children. We used prospective data from 247 children followed from birth through 6 y of age. Among those, 195 were examined at 9 mo using the Brunet-Lézine Scales, whereas 126 were examined at 3 y and 100 at 6 y using the McCarthy Scales of Children's Ability. A blood sample was collected from the umbilical cord to measure levels of dopamine and serotonin metabolites (homovanillic acid and 5-hydroxyindoleacetic acid, respectively) and ATPase activities (Na+K+-ATPase and Ca2+Mg2+-ATPase). The hand skill score at 6 y of age was significantly and negatively correlated with ATPase activities and with monoamine metabolite concentrations. No other cognitive score was related to biochemical measures at birth. Results were adjusted for child's sex, mother's educational level, duration of labor, and tea consumption. Composite scores of ATPase activities and monoamine metabolite concentrations measured at birth explained 29% of hand skill score variance at 6 y. Our results demonstrate the importance of prenatal factors on monoaminergic and ATPase activities in early human psychomotor development. This study also suggests that specific psychometric measures such as fine motor tests may be a better developmental measurement to correlate with biochemical factors than general cognitive scales.

The present study investigated the impact of acute and repeated administrations of corticosterone (10 mg/kg, twice daily, for 7 days) on serotonin (5-HT)(1A) receptor function, density and expression. The effect on 5-HT(1A) receptor function was assayed in rats by assessing the corticosterone-induced modulation of disruption of prepulse inhibition (PPI) of acoustic startle response induced by 8-OHDPAT, a 5-HT(1A) receptor agonist. Our experiments revealed that repeated but not acute treatment with corticosterone attenuated the 8-OHDPAT-evoked disruption of PPI without having any effect on PPI or startle amplitude alone. Chronic corticosterone treatment modulated also the neuronal activity of serotonergic pathways in the brain decreasing the level of 5-HIAA in the raphe nuclei and increasing both 5-HT and 5-HIAA levels in the hippocampus. Nevertheless, the effects of 8-OHDPAT on 5-HT metabolism were not changed by corticosterone. However, 5-HT(1A) receptor binding in the ventral hippocampus and entorhinal cortex but not in the raphe nuclei was decreased after chronic corticosterone treatment. It is concluded that chronically elevated corticosterone level is capable of inducing functional desensitization of 5-HT(1A) receptors which is paralleled by decreases in the 5-HT(1A) receptor binding in the ventral hippocampus and entorhinal cortex, the brain structures shown to be engaged in the regulation of PPI. Alterations in 5-HT(1A) receptors may be one of important mechanisms by which glucocorticoids/stress influence various psychiatric conditions.

Background: Meal ingestion is often associated with exacerbation of gastrointestinal symptoms in subjects with irritable bowel syndrome (IBS). Furthermore, recent preliminary data suggest that 5-hydroxytryptamine (5-HT) concentration in platelet poor plasma is elevated following meal ingestion in some subjects with diarrhoea predominant IBS (d-IBS) compared with healthy subjects, although it is not known whether this is related to postprandial symptomatology., Aim: To expand on previous data by evaluating a larger number of subjects but also to assess plasma 5-hydroxyindole acetic acid (5-HIAA) concentrations, 5-HT turnover, platelet 5-HT stores, and any relationship to symptomatology., Methods: We assessed platelet depleted plasma 5-HT and 5-HIAA concentrations for two hours (60 minute intervals) under fasting conditions, and then for a further four hours (30 minute intervals) after a standard carbohydrate meal (457 kcal), together with fasting platelet 5-HT concentrations in 39 female subjects with d-IBS (aged 19-52 years; mean age 33) and 20 healthy female volunteers (aged 20-46 years, mean age 28). IBS symptomatology, in particular abdominal pain and bloating, and urgency to defecate were assessed throughout the study, Results: When related to fasting levels, there was no statistically significant difference in postprandial plasma 5-HT concentrations between d-IBS and healthy subjects. However, when fasting levels were not taken into consideration, d-IBS subjects exhibited higher postprandial plasma 5-HT concentrations compared with healthy subjects (p=0.040). Furthermore, d-IBS subjects who exhibited postprandial symptomatology had higher levels of postprandial plasma 5-HT, whether assessed with respect to fasting baseline levels (p=0.069) or not (p=0.047), compared with d-IBS subjects who did not report postprandial symptomatology. This appeared to be associated with a concomitant increase in plasma 5-HIAA (p=0.161) but reduction in turnover (p=0.058). Lastly, d-IBS subjects had higher platelet concentrations of 5-HT than healthy subjects (p=0.009)., Conclusions: These data suggest that postprandial symptomatology may be associated with increased platelet depleted plasma 5-HT concentrations in female subjects with d-IBS. In addition, the presence of increased platelet stores of 5-HT may act as a useful marker for the diagnosis and management of d-IBS.

Purpose: To measure host responses to the antivascular agent DMXAA (5,6-dimethylxanthenone-4-acetic acid) and to compare them with those of other antivascular agents., Methods: Induction of tumor necrosis was measured in s.c. murine Colon 38 carcinomas growing in normal or tumor necrosis factor (TNF) receptor-1 knockout mice. Plasma and tumor tissue TNF concentrations were measured by ELISA. Plasma concentrations of 5-hydroxyindoleacetic acid (as a measure of serotonin release) and nitrite (as a measure of nitric oxide release) were measured by high-performance liquid chromatography., Results: Administration of DMXAA to tumor-bearing mice increased plasma and tumor tissue-associated TNF, in addition to increasing plasma nitric oxide, distinguishing its action from that of mitotic poisons that had an antivascular action. Results from TNF receptor-1 knockout mice showed that TNF played an important role in both its antitumor action and its host toxicity. Release of serotonin occurred in response to mitotic poisons, as well as to DMXAA. CONCLUCIONS: The antivascular action of DMXAA involves in situ production in tumor tissue of a cascade of vasoactive events, including a direct effect on vascular endothelial cells and indirect vascular effects involving TNF, other cytokines, serotonin, and nitric oxide. Now that Phase I clinical trials of DMXAA are completed, the optimization of this cascade in cancer patients is a major challenge. Plasma 5-hydroxyindoleacetic acid concentrations may provide a useful surrogate marker for the antivascular effects of DMXAA and other antivascular agents.

Objective: To determine whether glutamine (GLN), tryptophan (TRP), and tryptophan metabolite concentrations are higher in cerebralspinal fluid (CSF) dogs with naturally occurring portosystemic shunts (PSS), compared with control dogs., Animals: 11 dogs with confirmed PSS and 12 control dogs fed low- and high-protein diets., Procedure: Cerebrospinal fluid and blood samples were collected from all dogs. Serum and CSF concentrations of GLN, alanine, serine, TRP, 5-hydroxyindoleacetic acid (5-HIAA), and quinolinic acid (QUIN) were measured., Results: Cerebrospinal fluid concentrations of GLN, TRP, and 5-HIAA were significantly higher in PSS dogs, compared with control dogs fed high- or low-protein diets. Cerebrospinal fluid QUIN concentration was significantly higher in PSS dogs, compared with control dogs fed the low-protein diet. Serum QUIN concentration was significantly lower in PSS dogs, compared with control dogs fed either high- or low-protein diets., Conclusions and Clinical Relevance: An increase in CNS GLN concentration is associated with high CSF concentrations of TRP and TRP metabolites in dogs with PSS. High CSF 5-HIAA concentrations indicate an increased flux of TRP through the CNS serotonin metabolic pathway, whereas high CSF QUIN concentrations indicate an increased metabolism of TRP through the indolamine-2,3-dioxygenase pathway. The high CSF QUIN concentrations in the face of low serum QUIN concentrations in dogs with PSS indicates that QUIN production from TRP is occurring in the CNS. High concentrations of QUIN and other TRP metabolites in the CNS may contribute to neurologic abnormalities found in dogs with PSS and hepatic encephalopathy.

Recent evidence from our laboratory and others have suggested that the mechanism for a decrease in resting blood pressure after an acute bout of exercise is a centrally mediated decrease in total peripheral resistance. This study examined the effect of the central serotonergic system on post exercise hypotension (PEH) in 11 borderline hypertensive individuals (nine male, two female) aged 24.5 +/- 5.1 years. Each subject completed two, 30-min cycling bouts at 70% of VO2peak while under placebo or a selective serotonin re-uptake inhibitor (SSRI) treatment. Blood pressure was recorded directly from the radial artery, and treatments were randomised, double blinded and separated by at least 14 days. Baseline blood pressure was 145/72 mm Hg for systolic (SBP) and diastolic (DBP) respectively. Peripheral measures of serotonin (5-HT) were lower under SSRI treatment, whereas the major 5-HT metabolite, 5-hydroxyindoleacetic acid, was not significantly changed, indicating elevated central 5-HT levels. There was no difference in any of the haemodynamic variables between trials. Despite an increased heart rate for the initial 75 min post exercise, SBP was decreased as much as 23 mm Hg during the initial 60 min post exercise, after which it had returned to normal. DBP was unchanged after exercise. Circulating adrenaline (0.60 +/- 0.14 ng/mL to 1.3 +/- 1.6 ng/ml) and noradrenaline (0.27 +/- 0.31 ng/ml to 4.5 +/- 2.1 ng/ml) were significantly elevated during exercise. Both returned to pre-exercise levels within 15 min post exercise. Unexpectedly, oxygen uptake was slightly (5%), but significantly increased over the entire duration of the SSRI trial. We conclude that the central serotonergic system is not responsible for PEH in our borderline hypertensive population.

Background: Profiling of the plasma indoles tryptophan, 5-hydroxytryptophan (5-HTP), serotonin, and 5-hydroxyindoleacetic acid (5-HIAA) is useful in the diagnosis and follow-up of patients with carcinoid tumors. We describe an automated method for the profiling of these indoles in protein-containing matrices as well as the plasma indole concentrations in healthy controls and patients with carcinoid tumors., Methods: Plasma, cerebrospinal fluid, and tissue homogenates were prepurified by automated on-line solid-phase extraction (SPE) in Hysphere Resin SH SPE cartridges containing strong hydrophobic polystyrene resin. Analytes were eluted from the SPE cartridge by column switching. Subsequent separation and detection were performed by reversed-phase HPLC combined with fluorometric detection in a total cycle time of 20 min. We obtained samples from 14 healthy controls and 17 patients with metastasized midgut carcinoid tumors for plasma indole analysis. In the patient group, urinary excretion of 5-HIAA and serotonin was compared with concentrations of plasma indoles., Results: Within- and between-series CVs for indoles in platelet-rich plasma were 0.6-6.2% and 3.7-12%, respectively. Results for platelet-rich plasma serotonin compared favorably with those obtained by single-component analysis. Plasma 5-HIAA, but not 5-HTP was detectable in 8 of 17 patients with carcinoid tumors. In the patient group, platelet-rich plasma total tryptophan correlated negatively with platelet-rich plasma serotonin (P = 0.021; r = -0.56), urinary 5-HIAA (P = 0.003; r = -0.68), and urinary serotonin (P <0.0001; r = -0.80)., Conclusions: The present chromatographic approach reduces analytical variation and time needed for analysis and gives more detailed information about metabolic deviations in indole metabolism than do manual, single-component analyses.

Background: In patients suffering from chronic renal insufficiency (CRI) serotonin (5HT) metabolism is impaired, and plasma 5-hydroxyindoleacetic acid (5HIAA) levels (main metabolite of 5HT) are increased., Aim: In this study we aimed to give a detailed description of peripheral serotonin metabolism in healthy subjects and patients with CRI, and to evaluate the efficacy of hemodialysis in the elimination of cumulated 5HT and 5HIAA., Methods: 5HT (platelet rich plasma, platelet poor plasma, urine, HPLC with electrochemical detection) and 5HIAA (plasma, urine, HPCL with electrochemical detection) levels were evaluated in 14 conservatively treated (CT) and 12 hemodialysed (HD) patients with CRI and were compared to those of 60 healthy volunteers (HV)., Results: In patients with CRI accumulation of 5HT and 5HIAA in plasma with no changes in platelet 5HT content was revealed. 5HT renal and fractional excretion (FE) was markedly decreased in CRI. FE-5HT was < 1 in all investigated subjects, indicating its reabsorption in proximal tubules, or local degradation to 5HIAA. Due to the increased filtration load renal excretion of 5HIAA was not altered in CT patients, however it was decreased in HD patients. The relative participation of glomerular filtration in 5HIAA renal excretion increased in CRI. FE-5HIAA > 5 was found in 20% of HV and 15% of CT, pointing indirectly to 5HIAA intrarenal production. In CRI FE-5HIAA decreased. HD did not eliminate accumulated 5HT and 5HIAA effectively., Conclusion: Increased levels of 5HT and 5HIAA might exert metabolic effects contributing to the clinically manifested impairments characteristic for uremic syndrome. (Tab. 3, Fig. 3, Ref. 27.)

When the hypothalamic ventromedial nucleus and arcuate nucleus were destroyed in rats by treatment with monosodium glutamate in the neonatal stage, increase in the Lee index (body weight 1/3/body length) and in retroperitoneal fat as well as decreases in spontaneous motor activity, food consumption and growth hormone secretion function associated with hypothalamic low body length obesity (monosodium glutamate-treated obesity; MSG-OB) were observed as these rats grew. Treatment with sibutramine at 3 and 10 mg/kg p.o. once a day continuously for 14 days improved these parameters, and the degree of improvement was dose related. The plasma lipid values in MSG-OB rats, which were the same as those in normal rats, were decreased by consecutive administration of sibutramine. Levels of hypothalamic monoamines (MAs) such as norepinephrine, 5-HT (serotonin) and dopamine and their metabolites DOPAC, HVA and 5-HIAA were decreased in MSG-OB rats, and further decrease in them, though slight, was observed with consecutive daily administration of sibutramine, probably as a result of the feedback attributable to an increase in MA in synapses caused by inhibition of MA uptake by sibutramine. These results suggest that sibutramine can activate the MA nervous system by MA uptake inhibition in regions of the brain such as the lateral hypothalamic area and the paraventricular nucleus, which control food intake and sympathetic nerve activity, and the nigrostriatal area related to the extrapyramidal motor system, and thereby exhibit anti-obesity effects in the MSG-OB rat.

Elevated plasma serotonin is associated with primary pulmonary hypertension (PPH). To test whether this elevation could be related to platelet activation, the 2 pools of blood serotonin (platelets and plasma) and plasma 5-hydroxyindoleacetic acid (5-HIAA) as well as markers of platelet activation (alpha(IIb)beta(3), CD36, P-selectin, and CD63 membrane epitopes) were measured in 16 patients with severe PPH (group 1) before and at days 10 and 40 of treatment with a continuous infusion of epoprostenol (prostacyclin). The same biological parameters were also measured in 19 healthy subjects (group 2) and in 10 patients after cardiovascular surgery with extracorporeal circulation (group 3), a condition known to profoundly activate the platelets. Twelve PPH patients showed hemodynamic and clinical improvement, 3 remained stable, and 1 had the treatment stopped because of clinical aggravation. At day 0, mean plasma serotonin (5-hydroxytryptamine [5-HT]) concentration was much higher in PPH patients than in normal subjects (34.4+/-21.2 versus 9.1+/-6.0 nmol/L, respectively; P:<0.001) and positively correlated with total pulmonary resistance. The mean platelet 5-HT content was not significantly different in PPH compared with normal individuals. Mean plasma 5-HIAA concentrations were much higher in PPH than in normal patients (162+/-57 versus 61+/-7 nmol/L, respectively; P<0.001). These parameters did not significantly change during epoprostenol treatment. There was no correlation between the changes in plasma 5-HT during treatment and clinical or hemodynamic improvement. In PPH patients, the mean platelet volume significantly decreased (ANOVA, P<0.01) during treatment. Positive correlations were evidenced between the size of platelets and the number of alpha(IIb)beta(3) and CD36 epitopes. When compared with control platelets, the number of alpha(IIb)beta(3) epitopes detected on PPH platelets at day 0 tended to be higher, but this difference did not reach a statistical significance (41 300+/-7140 for PPH patients versus 36 010+/-3930 for control subjects, P=0.069). The number of CD36 epitopes, in the range of controls at day 0 (11 590+/-5080 for PPH patients versus 11 900+/-1790 for control subjects), decreased during treatment (ANOVA, P=0.038) and became significantly low at day 40 (8660+/-3520, P<0.001). The number of CD63 epitopes was not elevated, and P-selectin was never detected at any time point on PPH platelets. This glycoprotein profile indicates that the platelets of PPH patients were not highly activated but had an accelerated turnover and returned to normal under epoprostenol treatment without change of the elevated plasma serotonin, characteristic of PPH. In conclusion, neither platelet activation nor a significant alteration of the 5-HT endothelial metabolism explains the high level of plasma 5-HT in PPH patients. The 5-HT plasma concentration is not a predictive marker of the severity of PPH, and its evolution is independent of the clinical and hemodynamic status. Treatment by a potent antiaggregating agent, epoprostenol, does not affect the increase of plasma 5-HT, despite a therapeutic benefit.

We report on a 74-year-old carcinoid patient who, following acute myocardial infarction (MI) and percutaneous transluminal coronary angioplasty, suffered recurrent episodes of chest pain and ST-segment elevation on ECG. This was accompanied by elevation of urinary 5-hydroxy-indole acetic acid. A review of the patient's file revealed that during the 3 weeks prior to the MI, she had been treated inadvertently with a fivefold lower dosage of octreotide. Following the correction of octreotide dosage, episodes of chest pain resolved immediately. We therefore suggest that this patient suffered from recurrent coronary vasospasm due to uncontrolled carcinoid tumour.

Intestinal ischemia/reperfusion (I/R) causes serious systemic injury, mainly from a variety of bioactive substances released from the injured intestine. To assess the possible roles of serotonin (5-hydroxytryptamine, 5-HT), a bioactive amine mainly stored in the intestine, in I/R injury, we assayed the levels of tryptophan, 5-HT, and 5-hydroxyindole acetic acid (5-HIAA) in the blood and intestine in a rat I/R model. Plasma 5-HT increased significantly over time after reperfusion; the plateau level was obtained 4 h after reperfusion and was associated with an increase in 5-HIAA. Plasma tryptophan levels declined gradually after reperfusion. The ratio of 5-HIAA/5-HT was significantly higher in I/R rats than in control rats, suggesting that elevated 5-HT was quickly metabolized in the systemic circulation. In the intestine, 5-HT decreased dramatically, whereas tryptophan increased. This phenomenon was prominent in the severely damaged intestine. These findings suggest that the injured intestine released large amounts of 5-HT, whereas its synthesis in the injured intestine was suppressed. An increase in 5-HT in the circulation may be related to various circulatory disturbances observed in humans after intestinal ischemia.

Parameters of tryptophan (Trp) and related metabolism were compared in male Sardinian alcohol-preferring (sP) and -non-preferring (sNP) rats. Liver Trp pyrrolase activity was 38-58% higher in sP than in sNP rats, and this was associated with a greater expression of the enzyme mRNA as measured by multiprobe oligonucleotide solution hybridization. Moderately (about 10-19%), but significantly, lower concentrations of free serum, total serum, and brain Trp were also observed in sP compared with sNP rats. Concentrations of whole brain 5-hydroxytryptamine (5-HT) and its major metabolite 5-hydroxyindol-3-yl-acetic acid (5-HIAA) were, however, 14-21% higher in sP rats. Serum corticosterone concentration was 18% higher in sP rats. We conclude that alcohol preference in Sardinian rats is associated with increased liver Trp pyrrolase activity and mRNA expression leading to a decrease in Trp availability to the brain. Although a simple serotonin deficiency could not be demonstrated in the whole brain, the possibility could not be ruled out that a deficiency may be present in discrete areas of the brain of the sP rat.

To identify and control renal factors affecting plasma homovanillic acid (HVA), a dopamine metabolite and an indicator of brain dopamine activity in clinical research, nine healthy subjects were studied on 5 nonconsecutive days. First study day was the baseline and on the other days base, salt, water, or probenecid loads were given. On each day serial concentrations of HVA and serotonin metabolite 5-hyroxyindoleacetic acid (HIAA), another organic anion, in plasma were measured. Results suggested that base, salt, and water loads did not affect plasma concentrations of either metabolite. Probenecid, which partially blocks renal organic anion transport, induced similar increases in plasma HVA and HIAA. When plasma HVA:HIAA ratio was used to control for the effect of probenecid, differences between baseline and probenecid days were no longer significant. Results suggest that HVA and HIAA are similarly handled by the kidney and that simultaneously measured plasma HIAA could be used to distinguish renal influences in plasma HVA studies.

The development of reliable diagnostic tools for assessing alcoholism and harmful alcohol consumption is an utmost necessity for the success of efforts to prevent and treat alcohol-induced damage to both individuals and to society. A multinational study is underway to aid in the development of biological screening tools (state markers) which can, with good sensitivity and specificity, identify problem drinkers. To attain this goal information needs to be available on an individuals's drinking history and habits and related factors. A detailed instrument has been developed to obtain this information. The second goal of the study was to begin to develop diagnostic 'trait markers' which provide biological information on genetically determined predisposing and protective factors in the development of alcoholism. The developed questionnaire also provides background information on subject characteristics necessary for the development of trait markers. Centres will assay the obtained biological samples for 'traditional' and newly identified state markers of excessive alcohol consumption. These will include methanol measurements, gamma-glutamyltransferase, aspartate aminotransferase, carbohydrate-deficient transferrin, serotonin metabolite ratios, and erythrocyte aldehyde dehydrogenase. DNA obtained from the lymphocytes of subjects will be assayed for polymorphisms of alcohol- and aldehyde-metabolizing enzymes and dopamine receptor polymorphisms which can provide insights into protective and predisposing factors in alcoholism. The platelet enzymes, monoamine oxidase and adenylyl cyclase, will be assayed to assess the relationships between these putative trait markers and the genetic and environmental factors contributing to the aetiology of alcoholism. The current report is meant to introduce the study design and present a portion of the preliminary data gathered in the process of establishing this research programme.

Acetylcholine esterase, alpha 1-antichymotrypsin, homovanillic acid (HVA), 3-methoxy-4-hydroxy-phenylenglycol (MHPG), norepinephrine, dopamine, 5-hydroxy-indolacetic acid (5-HIAA), and gamma-aminobutyric acid (GABA) in the serum and cerebrospinal fluid (CSF) were quantified. Positive wave with the latency about 300 msec (P300) and electroencephalography (EEG) were examined in 10 patients with Alzheimer's disease, 10 patients with vascular dementia, and 10 age-matched healthy controls. Serum alpha 1-antichymotrypsin concentrations were significantly higher in the Alzheimer's disease group than in the vascular dementia and healthy control groups. Homovanillic acid concentrations in CSF were significantly lower in the vascular dementia group than in the Alzheimer's disease and the healthy control groups. A significant positive correlation was present between the mini-mental state examination (MMSE) score (normal range of 24 to 30) and the acetylcholine esterase concentration in the CSF. Significant negative correlations were present between the MMSE score and the P300 latency, between the MMSE score and the MHPG concentration in the CSF, between the MMSE and the norepinephrine concentration in the CSF, and between the MMSE score and the dopamine concentration in the CSF.

Background/aims: Serotonin is the diagnostic hallmark of midgut carcinoids, but the pathophysiology of spontaneous flushing is unknown. The aim of this study was to assess to what extent serotonin and catecholamine blood levels are related in time with spontaneous midgut carcinoid flush., Methods: Using specific radioenzymatic assays, we measured prospectively before, during, and after spontaneous flushing platelet-poor plasma and whole blood serotonin and plasma catecholamines and their metabolites in 10 patients with primary midgut carcinoids. Blood was drawn simultaneously from a forearm vein and an external jugular vein draining the flushing area., Results: During flushing, plasma serotonin and norepinephrine levels increased (P < 0.001) over preflush levels at both sampling sites. Intraflush serotonin and norepinephrine were twice as high (P < 0.01) in external jugular (9.57 +/- 1.40 ng/mL and 857 +/- 33 pg/mL, respectively) than in antecubital plasma (4.59 +/- 0.73 ng/mL and 471 +/- 26 pg/mL). Preflush and postflush levels were similar at both venous sites., Conclusions: Vein plasma serotonin and norepinephrine levels do increase during midgut carcinoid flush, especially in the flushing area. This may reflect a local release secondary to flush but also suggests a role for these bioamines in the pathogenesis of flushing.