Endothelial dysfunction and altered endothelial biomarkers in patients with post-COVID-19 syndrome and chronic fatigue syndrome (ME/CFS).
Haffke, Milan, Freitag, Helma, Rudolf, Gordon et al. · Journal of translational medicine · 2022 · DOI
Quick Summary
This study looked at whether blood vessel function is damaged in people with long COVID and ME/CFS. Researchers tested blood vessel function and measured specific proteins in the blood that reflect endothelial (blood vessel lining) health. They found that some patients with both conditions showed signs of blood vessel dysfunction, and had abnormal levels of certain proteins compared to healthy people.
Why It Matters
This research provides biological evidence that blood vessel dysfunction may contribute to fatigue and exercise intolerance in ME/CFS and post-COVID syndrome. Understanding these vascular abnormalities could lead to better diagnostic tools and targeted treatments for these debilitating conditions. The finding of elevated endothelial markers offers potential biomarkers for future research and clinical assessment.
Observed Findings
Endothelial dysfunction (diminished RHI <1.67) was present in 36% of ME/CFS patients and 31% of PCS patients, but in 0% of healthy controls.
Endothelin-1 concentration was significantly elevated in both ME/CFS and PCS patients compared to healthy controls and post-COVID healthy controls.
Angiopoietin-2 levels were reduced in PCS patients and post-COVID healthy controls compared to healthy controls.
In PCS patients, RHI showed paradoxical positive correlation with age, blood pressure, and BMI, whereas this pattern was absent in ME/CFS patients.
A subset of post-COVID patients showed altered endothelial biomarker profiles, suggesting heterogeneous pathomechanisms.
Inferred Conclusions
Endothelial dysfunction appears to contribute to symptoms in a subset of post-COVID and ME/CFS patients, potentially related to SARS-CoV-2 endothelial infection.
Different biomarker profiles and RHI associations among patient subgroups suggest ME/CFS and PCS may involve distinct or overlapping vascular pathomechanisms.
Endothelial biomarkers (particularly ET-1) may serve as clinical or research markers for vascular involvement in post-COVID and ME/CFS populations.
Remaining Questions
Why do only some ME/CFS and post-COVID patients show endothelial dysfunction, and what determines which patients are affected?
What This Study Does Not Prove
This study does not prove that endothelial dysfunction causes ME/CFS or post-COVID fatigue—only that they are associated. The cross-sectional design means we cannot determine if vascular damage occurs before, during, or after symptom development. Additionally, not all patients with these conditions showed endothelial dysfunction, suggesting other mechanisms may be involved in some cases.