Tryptophan metabolism in man (with special reference to rheumatoid arthritis and scleroderma)☆

Houpt, Joseph B.; Ogryzlo, M. A.; Hunt, M.

doi:10.1016/0049-0172(73)90022-x

Cited by 16 publications

(4 citation statements)

References 62 publications

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“…TRP is widely available on the market as a supplement for both animals and humans. However, there have been concerns that excess administration of TRP may cause oxidative stress in the cerebral cortex (91), as well as other adverse effects, including ataxia, tremors, diaphoresis, blurred vision, dry mouth, muscle stiffness, palpitations, urticaria, and the "eosinophilia-myalgia syndrome" (EMS) (92)(93)(94)(95)(96)(97). However, some of these side effects might have been caused by contaminated substance(s) in the former TRP preparations, but not TRP itself.…”

Section: Safety Of Oral Trp and Its Metabolitesmentioning

confidence: 99%

Tryptophan metabolism in animals important roles in nutrition and health

Yao

Fang²,

Yin³

et al. 2011

Front Biosci

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L-Tryptophan is a nutritionally essential amino acid for monogastric animals and preweaning ruminants because it cannot be synthesized in the body. Besides serving as a building block for proteins, tryptophan is a critical nutrient for the functions of nervous and immune systems. Over the past decades, much attention has been directed to study the role of tryptophan as a limiting amino acid in mammalian and avian nutrition. However, emerging evidence from recent studies shows that tryptophan and its metabolites (e.g., serotonin (5-hydroxytryptamine, 5-HT) and melatonin)) can regulate feed intake, reproduction, immunity, neurological function, and anti-stress responses. Additionally, tryptophan may modulate gene expression and nutrient metabolism to impact whole-body homeostasis in organisms. Thus, adequate intake of this amino acid from the diet is crucial for growth, development, and health of animals and humans.

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Section: Safety Of Oral Trp and Its Metabolitesmentioning

confidence: 99%

Tryptophan metabolism in animals important roles in nutrition and health

Yao

Fang²,

Yin³

et al. 2011

Front Biosci

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“…Before direct determinations became available a so-called 'tryptophan load test' [234,235] was routinely employed as a relatively sensitive index of PLP status [236,237]. The tryptophan load test is thought to refl ect the relative activity of PLP-dependent kynureninase [184].…”

Section: The 'Tryptophan Load Test' Pyridoxaldehydes (As Molecular Mmentioning

confidence: 99%

A heretofore undisclosed crux of Eosinophilia-Myalgia Syndrome: compromised histamine degradation

Smith

Garrett

2005

Inflamm. res.

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In contrast to early epidemiological evidence offering links between eosinophilia-myalgia syndrome (EMS) and microimpurities of L-tryptophan-containing dietary supplements (LTCDS), this account shows why reliance on a finite impurity from one manufacturer is both unnecessary and insufficient to explain the etiology of EMS. Excessive histamine activity has induced blood eosinophilia and myalgia (Greek: mys, muscle + algos, pain). Termination of the multiple actions of histamine is dependent on particular amine oxidases and histamine-N-methyltransferase. Histamine metabolism is rapid when these degradative reactions are operative. The latent effects of incurred histamine can be potentiated and aggravating when these mechanisms are impaired. Overloads of tryptophan supplements cause - among other relevant side-effects - an increased formation of formate and indolyl metabolites, several of which inhibit the degradation of histamine. Moreover, (non-EMS) subjects with hypothalamic-pituitary- adrenal (HPA) axis dysregulation have also manifested greatly increased sensitivities to incurred tryptophan and histamine. A final common pathway for syndromes characterized by eosinophilia with myalgia is now evident.

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“…To this end, the main aim of this study is to examine the sex-related differences in the KP in SSc patients considering the peripheral concentrations of TRP, KYNA, and KYN as well as kynurenine pathway enzyme activity indicators, indoleamine 2,3-dioxygenase In recent decades, there has been increasing discussion about the role of KP metabolites in SSc [5][6][7], as these metabolites are closely associated with inflammation [8]. Previous studies in SSc patients have shown an increase in the urinary excretion of certain TRP metabolites, particularly kynurenine (KYN), which allowed formulation of the hypothesis regarding dysregulation of TRP metabolism in SSc [9][10][11][12]. Furthermore, other studies revealed that metabolites of TRP formed along KP, specifically KYN and kynurenic acid (KYNA), have been found to inhibit fibroblast metabolism and proliferation and alleviate fibrosis [13,14].…”

Section: Introductionmentioning

confidence: 99%

Different Kynurenine Pathway Dysregulation in Systemic Sclerosis in Men and Women

Turska-Kozłowska,

Pedraz-Petrozzi,

Paluszkiewicz

et al. 2024

IJMS

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Systemic sclerosis (SSc), a predominantly female-affected systemic autoimmune disease, requires tailored treatment strategies contingent on organ involvement and symptom severity. Given SSc’s inflammatory nature, the involvement of the kynurenine pathway (KP) in its pathophysiology is underexplored. Our study aimed to investigate sex-related differences in KP activation among SSc patients and assess the impact of angiotensin-converting enzyme (ACE) inhibitors and estimated glomerular filtration rate (eGFR) on KP metabolite concentrations. We enrolled 48 SSc patients and 53 healthy controls, quantifying KP metabolites (tryptophan (TRP), kynurenine (KYN), and kynurenic acid (KYNA)) in serum via high-performance liquid chromatography. Separate multivariate analyses of covariance (MANCOVAs) for women and men were performed to ascertain mean differences between patients and healthy controls while correcting for age. For our secondary objective, we conducted a MANCOVA to explore disparities in ACE inhibitor users and non-users among patients, with BMI correction. Our findings revealed decreased TRP concentrations but increased KYNA/TRP ratio and KYN/TRP ratio in both male and female SSc patients compared to their respective controls. Unlike women, SSc males exhibited higher KYN concentrations and decreased KYNA/KYN ratio relative to their controls. Additionally, SSc patients using ACE inhibitors had higher serum KYNA levels than non-users. Notably, we established a significant correlation between eGFR and KYNA in SSc patients. These results indicate differential KP activation in male and female SSc patients, with males demonstrating heightened KP activation. While ACE inhibitors may influence the KP in SSc patients, further research is necessary to comprehensively understand their impact on symptoms and prognosis in the context of these KP alterations.

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Tryptophan metabolism in man (with special reference to rheumatoid arthritis and scleroderma)☆

Cited by 16 publications

References 62 publications

Tryptophan metabolism in animals important roles in nutrition and health

Tryptophan metabolism in animals important roles in nutrition and health

A heretofore undisclosed crux of Eosinophilia-Myalgia Syndrome: compromised histamine degradation

Different Kynurenine Pathway Dysregulation in Systemic Sclerosis in Men and Women

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