E3 PreliminaryPreliminaryPEM unclearMechanisticPeer-reviewedReviewed
Decreased NO production in endothelial cells exposed to plasma from ME/CFS patients.
Bertinat, Romina, Villalobos-Labra, Roberto, Hofmann, Lidija et al. · Vascular pharmacology · 2022 · DOI
Quick Summary
This study looked at how blood from ME/CFS patients affects the inner lining of blood vessels in a laboratory setting. Researchers found that blood vessels exposed to ME/CFS patient blood produced less of a substance called nitric oxide, which is important for healthy blood vessel function. This suggests that problems with blood vessel health in ME/CFS patients may involve reduced nitric oxide production.
Why It Matters
Endothelial dysfunction has been observed in some ME/CFS patients and may contribute to symptoms like fatigue and exercise intolerance. This research identifies a specific molecular mechanism—reduced nitric oxide production—that could underlie blood vessel dysfunction in ME/CFS, potentially opening new avenues for understanding disease pathophysiology and developing targeted treatments.
Observed Findings
- HUVECs exposed to ME/CFS-plasma produced significantly less nitric oxide than those exposed to healthy control plasma
- Nitric oxide deficiency occurred both at baseline and when cells were stimulated with eNOS-activating compounds
- GPCR agonists (bradykinin, histamine, acetylcholine) induced greater NO production deficits than TKR agonist (insulin) in ME/CFS-plasma conditions
- Inhibitory eNOS phosphorylation at Thr495 was elevated in ME/CFS-plasma-treated cells compared to control-plasma-treated cells
Inferred Conclusions
- ME/CFS patient plasma contains factors that impair eNOS-mediated nitric oxide production in endothelial cells
- eNOS dysfunction may represent a previously unrecognized component of endothelial dysfunction in ME/CFS
- The preferential impairment of GPCR-mediated signaling suggests a specific disruption in certain endothelial activation pathways in ME/CFS
Remaining Questions
- What specific molecular factors or circulating markers in ME/CFS plasma are responsible for reducing eNOS activity?
- Does reduced nitric oxide production occur in blood vessels of ME/CFS patients in vivo, and does it correlate with symptom severity?
- How does this endothelial dysfunction relate to other proposed mechanisms in ME/CFS, such as immune activation or mitochondrial dysfunction?
What This Study Does Not Prove
This laboratory study does not prove that the identified nitric oxide deficiency occurs in patients' bodies or causes ME/CFS symptoms. Because the study uses plasma components in cell culture rather than intact living systems, it cannot establish causation or determine whether this mechanism is primary or secondary to other disease processes. The findings require validation in larger patient cohorts and in vivo studies.
Tags
Symptom:Fatigue
Biomarker:Blood Biomarker
Method Flag:Small SampleExploratory OnlyWeak Case Definition
Metadata
- DOI
- 10.1016/j.vph.2022.106953
- PMID
- 35074481
- Review status
- Editor reviewed
- Evidence level
- Early hypothesis, preprint, editorial, or weak support
- Last updated
- 12 April 2026
About the PEM badge: “PEM required” means post-exertional malaise was an explicit required diagnostic criterion for participant inclusion in this study — not that PEM was studied, observed, or discussed. Studies using criteria that do not require PEM (e.g. Fukuda, Oxford) are tagged “PEM not required”. How the atlas works →
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