ArticleFrontiers in molecular neuroscience2023
Tryptophan catabolites, inflammation, and insulin resistance as determinants of chronic fatigue syndrome and affective symptoms in long COVID.
Article in Frontiers in molecular neuroscience, 2023. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 28 papers, 1 of them a synthesis 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
28 citing papers in PubMed, 1 synthesis or guideline pooled it, 51 citations in OpenAlex.
- Increased Insulin Resistance and Hyperglycaemia in Long COVID: A Systematic Review and Meta-Analysis.Expert reviews in molecular medicine · 2026Pooled it
- Hepato-Cardiac Axis in Epirubicin Toxicity: Role of Kynurenine Pathway and N-Acetylcysteine Antioxidant Intervention.Journal of applied toxicology : JAT · 2026Article
- Unifying the hallmarks of major depression through neuroimmune-metabolic-oxidative (NIMETOX) dysregulation: a mechanistic systems framework.Cellular & molecular immunology · 2026Review
- Network-based integration of metabolomics data from large-scale repositories.Metabolomics : Official journal of the Metabolomic Society · 2026Article
- Acute inflammation and fronto-striatal connectivity in the transition from acute to persistent fatigue after mild COVID-19: A longitudinal fMRI study.Brain, behavior, & immunity - health · 2026Article
- Kynurenic acid signaling expands in human and nonhuman primates and impairs dorsolateral prefrontal cortical cognition that is key to mental illness.Molecular psychiatry · 2026Article
- The kynurenine pathway in depression and schizophrenia: convergent signals, divergent states, and clinical signatures.EXCLI journal · 2026Review
- Immune remodeling and metabolic reprogramming in chronic fatigue: insights into GPCR signaling and epigenetic regulation.Frontiers in immunology · 2026Review
- The Post-COVID syndrome caused by excessive inflammation: pathogenesis, potential targets and therapeutic agents.Frontiers in pharmacology · 2026Review
- Differential Characteristics and Comparison Between Long-COVID Syndrome and Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS).Biomedicines · 2025Review
- Brain-targeted autoimmunity is strongly associated with Long COVID and its chronic fatigue syndrome as well as its affective symptoms.Journal of advanced research · 2025Article
- Role of Galanin system and insulin resistance parameters as predictive tools for diagnosis of Long-COVID patients.Biochemistry and biophysics reports · 2025Article
- Article
- Affective and chronic fatigue symptoms are associated with serum neuronal damage markers in Parkinson's disease.Scientific reports · 2025Article
- Printable molecule-selective core-shell nanoparticles for wearable and implantable sensing.Nature materials · 2025Article
- Observational
- The potential causes of myasthenia and fasciculations in severely ill ME/CFS patients: the role of disturbed electrophysiology.Frontiers in physiology · 2025Article
- Core features and inherent diversity of post-acute infection syndromes.Frontiers in immunology · 2025Review
- Decoding Fibromyalgia: Genetic Insights into Gut and Immune System Interactions.Journal of pain research · 2025Article
- LED-emitted blue light improves quality of life and reduces fatigue after COVID-19 infection.Postepy dermatologii i alergologii · 2024Article
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
5 authors at 4 institutions in 5 countries.
Funding
No grant is acknowledged in the PubMed record.
Abstract
Critical COVID-19 disease is accompanied by depletion of plasma tryptophan (TRY) and increases in indoleamine-dioxygenase (IDO)-stimulated production of neuroactive tryptophan catabolites (TRYCATs), including kynurenine (KYN). The TRYCAT pathway has not been studied extensively in association with the physiosomatic and affective symptoms of Long COVID. In the present study, we measured serum TRY, TRYCATs, insulin resistance (using the Homeostatic Model Assessment Index 2-insulin resistance, HOMA2-IR), C-reactive protein (CRP), physiosomatic, depression, and anxiety symptoms in 90 Long COVID patients, 3-10 months after remission of acute infection. We were able to construct an endophenotypic class of severe Long COVID (22% of the patients) with very low TRY and oxygen saturation (SpO2, during acute infection), increased kynurenine, KYN/TRY ratio, CRP, and very high ratings on all symptom domains. One factor could be extracted from physiosomatic symptoms (including chronic fatigue-fibromyalgia), depression, and anxiety symptoms, indicating that all domains are manifestations of the common physio-affective phenome. Three Long COVID biomarkers (CRP, KYN/TRY, and IR) explained around 40% of the variance in the physio-affective phenome. The latter and the KYN/TRY ratio were significantly predicted by peak body temperature (PBT) and lowered SpO2 during acute infection. One validated latent vector could be extracted from the three symptom domains and a composite based on CRP, KYN/TRY, and IR (Long COVID), and PBT and SpO2 (acute COVID-19). In conclusion, the physio-affective phenome of Long COVID is a manifestation of inflammatory responses during acute and Long COVID, and lowered plasma tryptophan and increased kynurenine may contribute to these effects.
Indexed as
Identifiers
What OpenQuestion holds
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.