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Elevated dimethylarginine, ATP, cytokines, metabolic remodeling involving tryptophan metabolism and potential microglial inflammation characterize primary open angle glaucoma.
Pulukool, SK, Bhagavatham, SKS, Kannan, V, Sukumar, P, Dandamudi, RB, Ghaisas, S, Kunchala, H, Saieesh, D, Naik, AA, Pargaonkar, A, et al
Scientific reports. 2021;(1):9766
Abstract
Glaucoma of which primary open angle glaucoma (POAG) constitutes 75%, is the second leading cause of blindness. Elevated intra ocular pressure and Nitric oxide synthase (NOS) dysfunction are hallmarks of POAG. We analyzed clinical data, cytokine profile, ATP level, metabolomics and GEO datasets to identify features unique to POAG. N9 microglial cells are used to gain mechanistic insights. Our POAG cohort showed elevated ATP in aqueous humor and cytokines in plasma. Metabolomic analysis showed changes in 21 metabolites including Dimethylarginine (DMAG) and activation of tryptophan metabolism in POAG. Analysis of GEO data sets and previously published proteomic data sets bins genes into signaling and metabolic pathways. Pathways from reanalyzed metabolomic data from literature significantly overlapped with those from our POAG data. DMAG modulated purinergic signaling, ATP secretion and cytokine expression were inhibited by N-Ethylmaleimide, NO donors, BAPTA and purinergic receptor inhibitors. ATP induced elevated intracellular calcium level and cytokines expression were inhibited by BAPTA. Metabolomics of cell culture supernatant from ATP treated sets showed metabolic deregulation and activation of tryptophan metabolism. DMAG and ATP induced IDO1/2 and TDO2 were inhibited by N-Ethylmaleimide, sodium nitroprusside and BAPTA. Our data obtained from clinical samples and cell culture studies reveal a strong association of elevated DMAG, ATP, cytokines and activation of tryptophan metabolism with POAG. DMAG mediated ATP signaling, inflammation and metabolic remodeling in microglia might have implications in management of POAG.
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Comparison of the Effect of Tanacethum Parthenium, 5-Hydroxy Tryptophan, and Magnesium (Aurastop) versus Magnesium Alone on Aura Phenomenon and Its Evolution.
Volta, GD, Zavarise, P, Perego, L, Savi, L, Pezzini, A
Pain research & management. 2019;:6320163
Abstract
None of the clinical trials on migraine conducted thus far have focused on the possibility to modulate the phenomenon of aura. Furthermore, whether proper management of aura results in a better control of the headache phase has been poorly investigated. In the setting of a single-center, pilot, clinical trial, we aimed at comparing the effects of Aurastop (a combination of tanacetum parthenium (150 mg extracted at 0.8% = 1.2 mg di of active parthenolide), griffonia simplicifoila (20 mg of 5-hydroxy tryptophan), and magnesium (185 mg of magnesium pidolatum)) with those of magnesium alone (2.25 grams/tablet, corresponding to 184 mg of Mg++) in the treatment of acute attacks of migraine with aura. Between June 2017 and June 2018, 50 consecutive patients (27/23 male/female; mean age, 31 [18-57] years) with at least 3 episodes of aura per year were included (t 0). Participants were instructed to keep track of the following 4 episodes of migraine with aura (t 1) and invited to assume (1) a tablet of Aurastop at the beginning of the following 2 episodes of aura and (2) a magnesium tablet alone at the occurrence of the third and fourth aura attacks. Forty-eight patients (96.0%) had >50% reduction in aura duration when treated with Aurastop vs. 7 patients (14.0%) when treated with magnesium alone (p < 0.001); 48 patients (96.0%) had >50% reduction of aura-related disability when receiving Aurastop vs. 5 patients (10.0%) when treated with magnesium alone (p < 0.001); however, patients receiving Aurastop did not need to take pain killers in 35% of aura attacks vs. 3% when assuming magnesium (p < 0.001). These results support the hypothesis that Aurastop might be effective in interfering with the phenomenon of aura and provide evidence that the clinical benefit attributable to this combination of molecules might be greater than that obtained with single compounds of proven effect on the biology of migraine.
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Metabolite profile analysis reveals association of vitamin B-6 with metabolites related to one-carbon metabolism and tryptophan catabolism but not with biomarkers of inflammation in oral contraceptive users and reveals the effects of oral contraceptives on these processes.
Rios-Avila, L, Coats, B, Chi, YY, Midttun, Ø, Ueland, PM, Stacpoole, PW, Gregory, JF
The Journal of nutrition. 2015;(1):87-95
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Abstract
BACKGROUND The use of oral contraceptives (OCs) has been associated with low plasma pyridoxal 5'-phosphate (PLP). The functional consequences are unclear. OBJECTIVES To determine whether functional vitamin B-6 insufficiency occurs in OC users and is attributable to OCs, we investigated the associations of PLP with metabolites of one-carbon metabolism, tryptophan catabolism, and inflammation in OC users, and evaluated the effects of OCs on these metabolites. METHODS Plasma metabolite concentrations were measured in 157 OC users (20-40 y of age). Associations between PLP and the metabolites were analyzed through use of generalized additive models and partial least squares-discriminant analysis (PLS-DA). Additionally, data from 111 of the 157 OC users were compared to previously reported data from 11 nonusers, at adequate and low vitamin B-6 status, with use of multivariate ANOVA. RESULTS PLP showed significant (P < 0.05) negative nonlinear association with homocysteine, glutathione, and ratios of asymmetric dimethylarginine to arginine, 3-hydroxykynurenine to 3-hydroxyanthranilic acid, and 3-hydroxykynurenine to kynurenic acid. PLS-DA supported these conclusions and identified 3-hydroxykynurenine and the 3-hydroxykynurenine-to-kynurenine ratio as discriminating biomarkers in women with PLP ≤30 nmol/L. Among the many differences, OC users had significantly higher plasma pyridoxal (157% at adequate and 195% at low vitamin B-6 status), 4-pyridoxic acid (154% at adequate and 300% at low vitamin B-6 status), xanthurenic acid (218% at low vitamin B-6 status), 3-hydroxyanthranilic acid (176% at adequate and 166% at low vitamin B-6 status), quinolinic acid (127% at low vitamin B-6 status), and nicotinamide (197% at low vitamin B-6 status). Biomarkers of inflammation were not associated with PLP, and no differences were found between the 2 groups. CONCLUSIONS PLP is associated with biomarkers of one-carbon metabolism and tryptophan catabolism but not with biomarkers of inflammation in OC users. Independent of vitamin B-6 status, OCs have effects on metabolites and ratios of one-carbon metabolism and tryptophan catabolism but not on biomarkers of inflammation. This study was registered at clinicaltrials.gov as NCT01128244. The study from which data for nonusers was derived was registered as NCT00877812.
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Serotonergic functioning and trait-impulsivity in attention-deficit/hyperactivity-disordered boys (ADHD): influence of rapid tryptophan depletion.
Zepf, FD, Stadler, C, Demisch, L, Schmitt, M, Landgraf, M, Poustka, F
Human psychopharmacology. 2008;(1):43-51
Abstract
OBJECTIVE The present study investigated the effects of rapid tryptophan depletion (RTD) and the ensuing reduction of central nervous levels of serotonin (5-HT) on reactive aggression with respect to personality factors comprising aspects of trait-impulsivity and -aggression in boys with attention-deficit/hyperactivity-disorder (ADHD). METHODS Twenty-two male adolescent patients with ADHD received the RTD test on one day, and, on another day a tryptophan balanced placebo in a double-blind within-subject crossover design. Impulsive personality factors and trait-impulsivity were assessed in advance of the study. Aggression was provoked using a competitive reaction time game 270 min after RTD/placebo intake. RESULTS RTD had a significant effect on increased aggressive behaviour with which low-grade impulsive patients responded. High-grade impulsive patients were not affected by RTD or even responded with increased aggressive behaviour while receiving placebo treatment. CONCLUSIONS The present study supports the hypothesis that 5-HT functioning in ADHD patients influences reactive aggression depending on aspects of trait-impulsivity. Future studies are necessary in order to detect the specific influence of ADHD as regards the relevance to 5-HT-induced changed aggressive responding.
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Interferon-alpha influences tryptophan metabolism without inducing psychiatric side effects.
Bannink, M, Fekkes, D, Van Gool, AR, Kruit, WH, Sleijfer, S, van der Holt, B, Eggermont, AM, Stoter, G, Hengeveld, MW
Neuropsychobiology. 2007;(3-4):225-31
Abstract
BACKGROUND Interferon-alpha (IFN-alpha) treatment is often associated with psychiatric side effects and has been found to lower the amount of tryptophan (TRP) available to the brain. The alterations in tryptophan metabolism might underlie the psychiatric side effects during treatment with IFN-alpha. METHODS In this study, 43 oncology patients treated with IFN-alpha were included. In order to study de novo depressions, depressed patients at baseline were excluded. Psychiatric evaluation comprising clinical judgment combined with a structured psychiatric interview and observer-based and self-report rating scales was performed at baseline and at 4 weeks, 8 weeks and 6 months after the start of treatment with IFN-alpha, and in the case of emerging psychopathology. Blood samples were drawn at the same evaluation times and assessed for concentrations of TRP, large neutral amino acids, kynurenine, 5-hydroxyindole acetic acid, neopterin and biopterin. RESULTS During treatment with IFN-alpha, several alterations in laboratory parameters occurred that were consistent with an increased degradation of peripheral TRP. Psychometric ratings revealed hardly any psychiatric changes. No consistent associations were found between changes in the laboratory assessments determined and the diverse psychiatric measures. CONCLUSION In this study, IFN-alpha was found to alter TRP metabolism without inducing psychiatric side effects. Therefore, a possible relationship between TRP metabolism and depression was not substantiated by this study.
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Impaired recognition of fear facial expressions in 5-HTTLPR S-polymorphism carriers following tryptophan depletion.
Marsh, AA, Finger, EC, Buzas, B, Soliman, N, Richell, RA, Vythilingham, M, Pine, DS, Goldman, D, Blair, RJ
Psychopharmacology. 2006;(3):387-94
Abstract
RATIONALE Genotype at the 5' promoter region (5-HTTLPR) of the serotonin transporter has been implicated in moderating the effects of acute tryptophan depletion on neurocognitive functioning. Acute tryptophan depletion has been associated with the processing of fear-relevant cues, such as emotional expressions, but the effect of genotype at the 5-HTTLPR has not been assessed. OBJECTIVE The present study investigated the effects of acute tryptophan depletion on the recognition of standardized facial expressions of emotions in healthy volunteers classified as ll homozygotes or s carriers. MATERIALS AND METHODS A double-blind between-groups design was used with volunteers randomly selected to ingest capsules containing an amino acid mixture specifically lacking tryptophan, or placebo capsules containing lactose. 5 h after capsule ingestion, subjects were required to identify anger, disgust, fear, happiness, sadness, and surprise expressions that progressed from neutral to each full emotional expression in 5% steps. RESULTS Tryptophan depletion significantly impaired the recognition of fearful facial expressions in s carriers but not ll homozygotes. This impairment was specific to fear expressions. No significant differences in the recognition of other expressions were found. Free tryptophan levels were correlated with fear recognition in s carriers but not ll homozygotes. CONCLUSIONS The effects of acute tryptophan depletion on the processing of emotional expressions varies as a function of genotype at the 5-HTTLPR. Depletion impairs the recognition of fear in s carriers but not ll homozygotes. This finding reinforces the importance of considering genotype when assessing the behavioral effects of pharmacologic modulation.
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Rapid tryptophan depletion improves decision-making cognition in healthy humans without affecting reversal learning or set shifting.
Talbot, PS, Watson, DR, Barrett, SL, Cooper, SJ
Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology. 2006;(7):1519-25
Abstract
Rapid tryptophan (Trp) depletion (RTD) has been reported to cause deterioration in the quality of decision making and impaired reversal learning, while leaving attentional set shifting relatively unimpaired. These findings have been attributed to a more powerful neuromodulatory effect of reduced 5-HT on ventral prefrontal cortex (PFC) than on dorsolateral PFC. In view of the limited number of reports, the aim of this study was to independently replicate these findings using the same test paradigms. Healthy human subjects without a personal or family history of affective disorder were assessed using a computerized decision making/gambling task and the CANTAB ID/ED attentional set-shifting task under Trp-depleted (n=17; nine males and eight females) or control (n=15; seven males and eight females) conditions, in a double-blind, randomized, parallel-group design. There was no significant effect of RTD on set shifting, reversal learning, risk taking, impulsivity, or subjective mood. However, RTD significantly altered decision making such that depleted subjects chose the more likely of two possible outcomes significantly more often than controls. This is in direct contrast to the previous report that subjects chose the more likely outcome significantly less often following RTD. In the terminology of that report, our result may be interpreted as improvement in the quality of decision making following RTD. This contrast between studies highlights the variability in the cognitive effects of RTD between apparently similar groups of healthy subjects, and suggests the need for future RTD studies to control for a range of personality, family history, and genetic factors that may be associated with 5-HT function.
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The effects of a branched chain amino acid mixture supplemented with tryptophan on biochemical indices of neurotransmitter function and decision-making.
Scarnà, A, McTavish, SF, Cowen, PJ, Goodwin, GM, Rogers, RD
Psychopharmacology. 2005;(4):761-8
Abstract
RATIONALE We have previously shown that a 60-g mixture of branched chain amino acids (BCAAs) lowers the plasma availability of the catecholamine precursors tyrosine (TYR) and phenylalanine (PHE) and produces biochemical and neuropsychological changes consistent with impaired dopamine neurotransmission. However, the BCAA mixture also lowers the ratio of tryptophan (TRP) to BCAA which could impair brain serotonin function. OBJECTIVES To determine the biochemical and neuropsychological effects of a BCAA mixture supplemented with TRP. METHODS We studied 32 healthy volunteers who were randomly and blindly allocated to either a single administration of amino acid mixture (60 g BCAA and 2 g TRP) or placebo. We carried out venous sampling to measure plasma levels of amino acids and performed selected cognitive tasks sensitive to monoamine manipulation 5 h after mixture ingestion. RESULTS Relative to placebo, the BCAA/TRP mixture substantially lowered the ratio of TYR+PHE:BCAA and increased plasma prolactin. The ratio of TRP:BCAA was also lowered but to a lesser extent. The BCAA/TRP mixture produced significant changes in a task of decision-making where volunteers showed reduced discrimination between gambles with large and small losses. CONCLUSIONS A 62 g BCAA/TRP mixture decreases the availability of TYR and PHE for brain catecholamine synthesis and increases plasma prolactin consistent with lowered brain dopamine function. Addition of 2 g TRP to the 60 g BCAA mixture does not prevent a reduction of the ratio TRP:BCAA relative to placebo. The effects of the BCAA/TRP mixture on decision-making suggest a general action of dopamine pathways on the processing of emotional information in risky choice, including punishment-related cues, consistent with suggestions that dopamine mechanisms mediate behavioural responses to aversive as well as appetitive stimuli in instrumental conditioning.
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The circadian rhythm of tryptophan in breast milk affects the rhythms of 6-sulfatoxymelatonin and sleep in newborn.
Cubero, J, Valero, V, Sánchez, J, Rivero, M, Parvez, H, Rodríguez, AB, Barriga, C
Neuro endocrinology letters. 2005;(6):657-61
Abstract
INTRODUCTION The hormone melatonin regulates the sleep and this pineal hormone is synthesized in the organism from the amino acid tryptophan. It is known that breast-fed babies have better sleep patterns and a better entrained sleep/wake cycle than bottle-fed babies (adapted formula). OBJECTIVE To compare the circadian rhythm of 6-sulfatoxymelatonin (aMT6s)--the metabolite of melatonin excreted in the urine--in urine of bottle-fed and breast-fed children, and relate it to the circadian rhythm of tryptophan in breast milk, also evaluating the possible effects on the baby's night-time rest. METHODS 16 infants of 12 weeks of age were studied, divided into two groups depending on their exclusively natural or artificial feeding. The circadian rhythm of 6-sulfatoxymelatonin in urine was measured for the two groups of infants and for the breast-feeding mothers. In the breast milk, the circadian rhythm of the amino acid tryptophan was measured. The rest of the infants was tested by wrist actimeters for a week and the sleep parameters of the infants were measured and evaluated. RESULTS The tryptophan in the breast milk presented a circadian rhythm with acrophase at around 03:00. This affected the 6-sulfatoxymelatonin circadian rhythm with acrophase at 06:00 in the breast-fed infants, and also promoted nocturnal sleep. Assumed sleep, actual sleep, and sleep efficiency were significantly increased in the breast fed infants with respect the formula fed infants. CONCLUSION A temporal relationship was observed between the circadian rhythm of 6-sulfatoxymelatonin of the exclusively breast-fed babies and that of tryptophan in the mother's milk. Acting this amino acid as a zeitgeber entrainment of the biological rhythms in the breast-fed infant.
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Reversed diurnal variation in depression: associations with a differential antidepressant response, tryptophan: large neutral amino acid ratio and serotonin transporter polymorphisms.
Joyce, PR, Porter, RJ, Mulder, RT, Luty, SE, McKenzie, JM, Miller, AL, Kennedy, MA
Psychological medicine. 2005;(4):511-7
Abstract
BACKGROUND Although diurnal variation of mood is a widely recognized symptom of depression, the clinical, neurobiological and psychopharmacological significance of this symptom has not previously been reported. METHOD A total of 195 depressed out-patients underwent a detailed clinical and neurobiological assessment, and were then randomized to treatment with either fluoxetine or nortriptyline. RESULTS Of the 195 depressed patients, 62 had a pattern of reversed diurnal variation (i.e. worse in the evening). Those with reversed diurnal variation had a poorer response to a serotonergic anti-depressant, were less likely to have bipolar II disorder, had a higher tryptophan: large neutral amino acid ratio and had different allele frequencies of the polymorphisms in the promoter region of the serotonin transporter. CONCLUSIONS These findings raise the possibility of serotonergic influence on diurnal variation, and that the symptom of reversed diurnal variation is of relevance to antidepressant prescribing.