Dysregulation of the Kynurenine Pathway, Cytokine Expression Pattern, and Proteomics Profile Link to Symptomology in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS). — CFSMEATLAS
Dysregulation of the Kynurenine Pathway, Cytokine Expression Pattern, and Proteomics Profile Link to Symptomology in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS).
Kavyani, Bahar, Ahn, Seong Beom, Missailidis, Daniel et al. · Molecular neurobiology · 2024 · DOI
Quick Summary
This study found that ME/CFS patients have imbalances in a particular chemical pathway in their body (the kynurenine pathway) that appears connected to inflammation and symptom severity. The researchers discovered that higher levels of one early chemical in this pathway correlated with worse symptoms, while lower levels of later chemicals in the pathway might affect how cells produce energy. Interestingly, they also found that five of the most significantly changed proteins in ME/CFS patients are involved in gut health, suggesting the gut microbiome may play an important role in the disease.
Why It Matters
This research identifies specific, measurable biological abnormalities in ME/CFS that could eventually lead to diagnostic biomarkers and targeted treatments. The novel finding linking gut health proteins to ME/CFS pathology opens an entirely new avenue for investigation and potential intervention, particularly given growing evidence that the microbiome influences systemic inflammation and the kynurenine pathway.
Observed Findings
Plasma kynurenine levels were elevated in ME/CFS patients and correlated with symptom severity.
Downstream kynurenine metabolites (3-HK, 3-HAA, QUIN, PIC) were reduced in ME/CFS patients, potentially impairing cellular energy production.
Hepcidin levels were decreased by approximately 50% in ME/CFS patients, suggesting iron dysregulation or possible systemic hypoxia.
Five of seven most significantly modulated proteins in ME/CFS patient plasma have roles in gut barrier function and health.
Inflammatory cytokine patterns were dysregulated and correlated with kynurenine pathway disturbances.
Inferred Conclusions
Inflammation-driven dysregulation of the kynurenine pathway is mechanistically linked to ME/CFS symptomology.
Reduced downstream kynurenine metabolites may contribute to impaired cellular energy metabolism in ME/CFS.
Gut barrier dysfunction or microbiome dysbiosis may be a significant factor in ME/CFS pathogenesis, potentially via effects on systemic kynurenine pathway regulation.
Iron dysregulation and possible tissue hypoxia may be relevant pathogenic features worthy of further investigation.
Remaining Questions
Does kynurenine pathway dysregulation in ME/CFS cause symptoms and energy deficit, or is it a consequence of other primary pathogenic processes?
What This Study Does Not Prove
This study demonstrates associations between biomarkers and symptoms but does not prove that kynurenine pathway dysregulation causes ME/CFS symptoms or that gut microbiome alterations are the primary driver of disease. The cross-sectional design cannot establish causality, temporal relationships, or whether observed changes are primary pathogenic mechanisms versus secondary consequences of illness. Additionally, plasma biomarker levels may not fully reflect tissue-specific or compartmentalized processes.