Advancing ME/CFS Research: Identifying Targets for Intervention and Learning from Long COVID Dec. 12-13, 2023

See also abstract from a 2022 ISMRM presentation: Lower Cerebral Venous Oxygenation in Post-acute Sequelae of COVID-19 (I can't find a subsequent publication)

Post-COVID Syndrome (PCS) is highly prevalent amongst COVID-19 survivors. Neuropsychiatric symptoms are often reported in patients with PCS, suggesting brain involvement in the early stages of COVID-19. One potential etiology is the cerebral microcirculation dysfunction due to SARS-CoV-2 infection, which may affect oxygen delivery and consumption in the brain. In the present study, we investigated the changes in cerebral venous oxygenation, which reflects the balance between oxygen supply and consumption, in convalescent COVID-19 participants with PCS. Our results showed that participants with PCS had altered venous oxygenation in their brain, which was also associated with slower locomotion.
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These findings suggesting increased oxygen extraction in the brain are opposite to findings indicating impaired peripheral oxygen extraction for muscles.
 
SNT Gatchaman said:
“Structural and Oxygen Metabolic Magnetic Resonance Imaging of long-COVID and ME/CFS” Xiang Xu (Icahn/Mt Sinai)
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I just watched this again, attempting to gather info on how POT(S) / OI / cerebral blood flow could be coherently understood (Day 2 @ 3h 07m).

Note that they found differences in LC vs HC but not CFS vs HC/LC. Apart from the disease duration differences, the "CFS" patients may therefore be less well characterised and some may not fulfil modern criteria for ME/CFS with PEM, while perhaps it's more likely that the LC cohort does. We'll have to wait for a publication to evaluate that.

My summary notes —

- Used Fukuda for LC and CFS inclusion, with LC needing confirmed infection and subsequent ongoing symptoms

- TRUST (T2 Relaxation Under Spin-Tagging)
- Measures venous oxygenation (Yv) - superior sagittal sinus (ie SvO2)
- Compare against SpO2 as surrogate for arterial oxygenation (Ya)

- OEF (Oxygen Extraction Fraction)
- OEF = Ya - Yv
- Yv decreased in LC, not CFS
- OEF increased in LC, not CFS
- But note outliers in CFS

- CMRO2 (Cerebral metabolic rate of oxygen consumption)
- "Remarkably well-conserved in normal conditions"
- CMRO2 = Ca x CBF x OEF
- Ca is a constant representing the amount of oxygen-carrying molecules per unit volume of blood
- If OEF increased then accompanied by decreased CBF

- CBF measured by phase-contrast MRI of the 4 arteries (carotid, vertebrals)
- No significant differences between HC/LC/CFS
- But one LC low outlier

- Physical functioning positively correlated with SvO2 (Yv)
- General fatigue is negatively correlated with SvO2 (Yv)
 
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