ReviewFrontiers in immunology2021
Amino Acid Trp: The Far Out Impacts of Host and Commensal Tryptophan Metabolism.
Review in Frontiers in immunology, 2021. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 63 papers, 2 of them syntheses that pooled it.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
63 citing papers in PubMed, 2 syntheses or guidelines pooled it, 98 citations in OpenAlex.
- Metabolomics and Cardiovascular Risk in Patients with Heart Failure: A Systematic Review and Meta-Analysis.International journal of molecular sciences · 2024Pooled it
- The Mechanism Underlying the Influence of Indole-3-Propionic Acid: A Relevance to Metabolic Disorders.Frontiers in endocrinology · 2022Pooled it
- Mechanism-First Psychobiotics: Fermented Vegetables, Dairy, and Soy for Depression and Anxiety.International journal of molecular sciences · 2026Review
- Insomnia: the gut microbiome connection, prospects for probiotic and postbiotic therapies, and future directions.Journal of advanced research · 2026Review
- Highly sensitive enantiomeric detection of tryptophan using microchannel-based chiral sensors.Mikrochimica acta · 2026Article
- Regulation of infant gut microbiota and metabolic pathways by human milk oligosaccharides: a multi-omics investigation.RSC advances · 2026Article
- Nanomedicine-Driven Therapeutic Strategies for Rheumatoid Arthritis-Associated Depression: Mechanisms and Pharmacological Progress.Pharmaceuticals (Basel, Switzerland) · 2026Review
- A cross-kingdom metabolite signal: tryptophan fromFrontiers in microbiology · 2026Article
- Nutritional interventions for late-life depression: evidence, mechanisms, and clinical assessment tools.Frontiers in nutrition · 2026Review
- Gut microbiota-derived tryptophan metabolites: molecular mechanisms, nutritional strategies and implications for swine health.Frontiers in veterinary science · 2026Review
- The nasal-oral microbiome axis in allergic rhinitis: environmental triggers, microbial dysbiosis, and immune dysregulation.Frontiers in allergy · 2026Review
- Harnessing Dietary Tryptophan: Bridging the Gap Between Neurobiology and Psychiatry in Depression Management.International journal of molecular sciences · 2026Review
- Co-fermentation ofFrontiers in nutrition · 2026Article
- Article
- Pediococcus acidilactici GR-5 alleviates hyperuricemia by degrading purine nucleosides and improving gut microbiota metabolism.NPJ science of food · 2025Article
- Indole Propionic Acid Regulates Gut Immunity: Mechanisms of Metabolite-Driven Immunomodulation and Barrier Integrity.Journal of microbiology and biotechnology · 2025Review
- Roux-en-Y gastric bypass surgery decreases intestinal aryl hydrocarbon receptor signaling in male mice.Physiological reports · 2025Article
- The inconsistent pathogenesis of endometriosis and adenomyosis: insights from endometrial metabolome and microbiome.mSystems · 2025Article
- Gut-brain connection in schizophrenia: A narrative review.World journal of psychiatry · 2025Review
- Targeting gut microbiota and its associated metabolites as a potential strategy for promoting would healing in diabetes.World journal of diabetes · 2025Review
3 more citing papers are in PubMed but not listed here.
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
3 authors at 1 institution in 1 country.
Funding
Abstract
Tryptophan (Trp) is an essential amino acid primarily derived from the diet for use by the host for protein synthesis. The intestinal tract is lined with cells, both host and microbial, that uptake and metabolize Trp to also generate important signaling molecules. Serotonin (5-HT), kynurenine and its downstream metabolites, and to a lesser extent other neurotransmitters are generated by the host to signal onto host receptors and elicit physiological effects. 5-HT production by neurons in the CNS regulates sleep, mood, and appetite; 5-HT production in the intestinal tract by enterochromaffin cells regulates gastric motility and inflammation in the periphery. Kynurenine can signal onto the aryl hydrocarbon receptor (AHR) to elicit pleiotropic responses from several cell types including epithelial and immune cells, or can be further metabolized into bioactive molecules to influence neurodegenerative disease. There is a remarkable amount of cross-talk with the microbiome with regard to tryptophan metabolites as well. The gut microbiome can regulate the production of host tryptophan metabolites and can use dietary or recycled trp to generate bioactive metabolites themselves. Trp derivatives like indole are able to signal onto xenobiotic receptors, including AHR, to elicit tolerogenic effects. Here, we review studies that demonstrate that tryptophan represents a key intra-kingdom signaling molecule.
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Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.