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Endothelial dysfunction and altered endothelial biomarkers in patients with post-COVID-19 syndrome and chronic fatigue syndrome (ME/CFS)


Senior Member

Background: Fatigue, exertion intolerance and post-exertional malaise are among the most frequent symptoms of Post-COVID Syndrome (PCS), with a subset of patients fulfilling criteria for Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS). As SARS-CoV-2 infects endothelial cells, causing endotheliitis and damaging the endothelium, we investigated endothelial dysfunction (ED) and endothelial biomarkers in patients with PCS.

Methods: We studied the endothelial function in 30 PCS patients with persistent fatigue and exertion intolerance as well as in 15 age- and sex matched seronegative healthy controls (HCs). 14 patients fulfilled the diagnostic criteria for ME/CFS. The other patients were considered to have PCS. Peripheral endothelial function was assessed by the reactive hyperaemia index (RHI) using peripheral arterial tonometry (PAT) in patients and HCs. In a larger cohort of patients and HCs, including post-COVID reconvalescents (PCHCs), Endothelin-1 (ET-1), Angiopoietin-2 (Ang-2), Endocan (ESM-1), IL-8, Angiotensin-Converting Enzyme (ACE) and ACE2 were analysed as endothelial biomarkers.

Results: Five of the 14 post-COVID ME/CFS patients and five of the 16 PCS patients showed ED defined by a diminished RHI (< 1.67), but none of HCs exhibited this finding. A paradoxical positive correlation of RHI with age, blood pressure and BMI was found in PCS but not ME/CFS patients. The ET-1 concentration was significantly elevated in both ME/CFS and PCS patients compared to HCs and PCHCs. The serum Ang-2 concentration was lower in both PCS patients and PCHCs compared to HCs.

Conclusion: A subset of PCS patients display evidence for ED shown by a diminished RHI and altered endothelial biomarkers. Different associations of the RHI with clinical parameters as well as varying biomarker profiles may suggest distinct pathomechanisms among patient subgroups.


Senior Member
We have an #endothelial-repair protocol on the discord. Might want to check it out
Ah cool it's the one we chatted about. Yeah I need to try and source some of the meds.. Everything is so difficult with ME sigh.

Edit: you don't think ara would be useful though in addition? I can't take it atm anyway but just wondering. You also had said that you had to stay on to keep the benefits - is there any way we can just repair the tissue and it'll stay healed..
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Senior Member
I wonder if endothelial dysfunction in ME/CFS/Long COVID is linked to endothelial Insulin Resistance (this cause endothelial dysfunction via impaired vasodilation of the microvasculature)...

Valtrex/valacyclovir is often used as a long lasting treatment for ME/CFS and this recent paper released in sept 2022 shows that this AntiHerpetic Drug is improving insulin sensitivity!

Acyclovir alleviates insulin resistance via activating PKM1 in diabetic mice - ScienceDirect