Research: Endothelial dysfunction

Endothelial dysfunction in ME/CFS patients

This new research from Oystein Fluge, Olav Mella et al in Norway provides further support for the role of endothelial dysfunction in ME/CFS – and possibly in Long Covid as well.

The endothelium is a thin membrane that lines the inside of the heart and blood vessels.

Endothelial cells release substances that control vascular relaxation and contraction as well as enzymes that control blood clotting, immune function and platelet (a colourless substance in the blood) adhesion.

Research into endothelial dysfunction in ME/CFS is summarised and referenced in the Research section of the 2022 ME/CFS/PVFS Clinical & Research Guide (also known as the ‘purple book')

The full Research paper can be seen from the button below


Objective: A few earlier studies have found impaired endothelial function in patients with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS). The present study investigated large-vessel and small-vessel endothelial function in patients with ME/CFS.

Study design: The study was a substudy of the RituxME trial, a national, multicenter, randomized, double-blind, placebo-controlled phase III study on the effect of rituximab vs. placebo in ME/CFS patients in Norway. Flow-mediated dilation (FMD) and post-occlusive reactive hyperemia (PORH) was measured at baseline and after 18 months of treatment in 39 patients and compared with healthy controls. Other outcome measures were symptom severity and various physical function measures.

Results: ME/CFS patients had markedly reduced FMD compared to healthy controls at baseline (5.1% vs. 8.2%, p< 0.0001, adjusted for arterial diameter and sex), and significantly lower microvascular regulation measured by PORH than healthy controls (1354 PU vs. 2208 PU, p = 0.002). There were no differences between the treatment and placebo groups in symptom changes or vascular measures. As a group, the ME/CSF patients experienced a slight, but significant improvement in clinical symptoms after 18 months. PORH, but not FMD, was similarly improved (1360 to 1834 PU, p = 0.028). There was no significant correlation between FMD and PORH. There were non-significant tendencies towards associations between symptom severity/physical function measures and lower FMD and PORH, and a significant correlation between PORH and steps per 24 hours at baseline.

Conclusions: ME/CFS patients had reduced macro- and microvascular endothelial function, indicating that vascular homeostasis may play a role in the clinical presentation of this disease.

See also: 2022 study of Endothelial Dysfunction in ME/CFS

Dr Charles Shepherd,
Trustee and
Hon. Medical Adviser
to the ME Association.
Member of the 2018-2021 NICE Guideline Committee.
Member of the 2002 Independent Working Group on ME/CFS.

Dr Charles Shepherd
Shopping Basket