Detection of Elevated Level of Tetrahydrobiopterin in Serum Samples of ME/CFS Patients with Orthostatic Intolerance: A Pilot Study.
Gottschalk, Carl Gunnar, Whelan, Ryan, Peterson, Daniel et al. · International journal of molecular sciences · 2023 · DOI
Quick Summary
This study looked at a molecule called BH4 in the blood of ME/CFS patients, particularly those who experience dizziness when standing up. The researchers found that ME/CFS patients have higher levels of BH4 than healthy people, and this may be connected to oxidative stress (harmful chemical reactions in the body). This finding could help explain why some ME/CFS patients struggle with dizziness and blood flow problems.
Why It Matters
Orthostatic intolerance affects a substantial subset of ME/CFS patients and current treatments are limited. Identifying BH4 dysregulation as a potential biomarker and mechanism opens new avenues for understanding cardiovascular and neurological complications in ME/CFS, potentially leading to targeted therapeutic interventions.
Observed Findings
Serum BH4 levels were significantly elevated in CFS patients compared to healthy controls.
BH4 levels remained elevated across all three patient subgroups (CFS, CFS+OI, and CFS+OI+SFN).
Elevated BH4 in CFS+OI patients showed correlation with markers of oxidative stress in microglial cell culture assays.
The association between elevated BH4 and oxidative stress was demonstrated using ROS production assays.
Inferred Conclusions
BH4 dysregulation may represent a shared biochemical abnormality across ME/CFS phenotypes.
Elevated BH4 in orthostatic intolerance may reflect an oxidative stress response and could contribute to endothelial dysfunction.
BH4 metabolism represents a potential molecular target for understanding and treating ME/CFS and its cardiovascular complications.
Remaining Questions
Is elevated BH4 a cause or consequence of ME/CFS pathology, or merely a biomarker of oxidative stress?
Do BH4 levels correlate with severity of orthostatic intolerance symptoms or disease progression?
Would interventions targeting BH4 metabolism or the underlying oxidative stress improve symptom severity in ME/CFS+OI patients?
What This Study Does Not Prove
This study does not prove that elevated BH4 causes orthostatic intolerance or ME/CFS symptoms—it only shows an association. The findings are preliminary from a small pilot study and have not been replicated in larger populations. The study does not establish that targeting BH4 metabolism would be an effective treatment.