Single-cell transcriptomics of the immune system in ME/CFS at baseline and following symptom provocation, PP, Ahmed, Hanson

jaybee00

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https://www.biorxiv.org/content/10.1101/2022.10.13.512091v1

SUMMARY
ME/CFS is a serious and poorly understood disease. To understand immune dysregulation in ME/CFS, we used single-cell RNA-seq (scRNA-seq) to examine immune cells in cohorts of patients and controls. Post-exertional malaise (PEM), an exacerbation of symptoms following strenuous exercise, is a characteristic symptom of ME/CFS. Thus, to detect changes coincident with PEM, we also performed scRNA-seq on the same cohorts following exercise. At baseline, ME/CFS patients displayed dysregulation of classical monocytes suggestive of inappropriate differentiation and migration to tissue. We were able to identify both diseased and more normal monocytes within patients, and the fraction of diseased cells correlated with metrics of disease severity. Comparing the transcriptome at baseline and post-exercise challenge, we discovered patterns indicative of improper platelet activation in patients, with minimal changes elsewhere in the immune system. Taken together, these data identify immunological defects present at baseline in patients and an additional layer of dysregulation following exercise.

Highlights ME/CFS is a debilitating disease with unknown causes. Here, we provide, for the first time, an extensive single cell resolution dataset detailing the gene expression programs of circulating immune cells of ME/CFS cases at baseline and after symptom provocation. We were able to detect robust dysregulation in certain immune cells from patients, with dysregulation of classical monocytes manifesting the strongest signal. Indeed, the fraction of aberrant monocytes in ME/CFS patients correlated with the degree of disease severity. Surprisingly, platelet transcriptomes were also altered in ME/CFS, and they were the only component of the immune system that showed large-scale changes following symptom provocation.
 

Consul

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I have been hyped for this study about the monocytes, Cort Johnson mentioned it in a recent article. Looks to me like the big deal is the two tall columns in figure 2A showing 800 genes expressed different between patients and controls. I guess thats concidered alot then. In the twitter thread i think Herbert Polster suggests these monocytes are migrating into the brain.

(edit: im talking about the cluster 2 cells which is classical monocytes)
 
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This is awesome. I'm pleased they found 2 clear problems in monocytes and platelets, not 100. It allows researchers to focus.

In particular I care about the platelet response because it correlates with PEM. Seems like pre-exercise we have few active platelets, afterwards our platelets get activated very strongly and catch up to normal people.

My theory is the platelets are being activated by eATP released by red blood cells trying to move through blood vessels that are insufficiently dilated (tying Hanson's work here to Carmen Scheinbenbogen's). We have more eATP than a healthy person because of the insufficient dilation, enough to bring our platelets up to normal, but doing so comes at high cost - PEM.

Weird monocytes are also being linked to blood vessel problems in long covid by this guy Bruce Patterson: https://www.frontiersin.org/articles/10.3389/fimmu.2021.746021/full

So to me what's exciting here is the research is finally circling in on the answer: circulation. Less "something in the blood" as "something's up with the blood":

Cort wrote about Patterson's work a while ago:
https://www.healthrising.org/blog/2021/07/21/patterson-cracked-long-covid/

"[monocytes] appear to be unique in the patrolling behavior they exhibit around the blood vessels.

The authors believe these monocytes were drawn to coronavirus-infected cells in the blood vessels, where they ingested them, and then put a coronavirus protein on their surface to alert the immune system. The problem in long COVID occurs when they are drawn to the blood vessels and injure them, or cause the blood vessels to inappropriately dilate."


It potentially also ties in with Systrom's work on circulation and the cholinergic systems that control vasodilation and vasoconstriction. I'm relentlessly optimistic I know but I can't help feel we're getting somewhere!
 
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My theory is the platelets are being activated by eATP released by red blood cells trying to move through blood vessels that are insufficiently dilated (tying Hanson's work here to Carmen Scheinbenbogen's). We have more eATP than a healthy person because of the insufficient dilation, enough to bring our platelets up to normal, but doing so comes at high cost - PEM.
Interesting theory. Does anyone have experience taking a vasodilator and then doing an exercise challenge? Or know of a study that did the same?
For example, could 20 or 30 mg of Sildenafil (generic Viagra) be used as a PEM blocker? Or say 20 mg before exercise and 20 mg after? Just throwing it out there.
Yes, I know I am setting myself up for a few jokes.
 

Wishful

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Does anyone have experience taking a vasodilator and then doing an exercise challenge?
That's also my question about vessel/blood hypotheses: where's the evidence from vessel/blood modulators? I don't recall any threads about numerous people effectively treating their ME with aspirin, viagra, coumarin, etc. I would also have expected strenuous exercise to affect blood flow, oxygenation, etc, yet I don't notice any changes in my ME symptoms between exercise and rest.
 
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Are you saying that ATP is being released when and where it should'nt?
well, red blood cells release extracellular ATP (eATP) to ask blood vessels to dilate. that's one signalling mechanism they use. So i'm not sayign that the release is inappropriate per se, just that if there is no reponse from the blood vessel and so the signal builds up, you could end up with blood vessels full of lots of eATP. That could, at a certain point, begin to look like a crisis signal to other parts of the immune system.

Certainly that's why eATP activates platelets - it's a sign cells are broken and leaking their insides out, and platelets respond to help heal that up.

(n.b. many other things also activate platelets, and many other mechanisms dilate blood vessels. Nobody should get the impression my theory is definitive! Theories are cheap and it's easy to spell out in words something that looks logically perfect but has no bearing on biological reality.)
 
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Interesting theory. Does anyone have experience taking a vasodilator and then doing an exercise challenge? Or know of a study that did the same?
For example, could 20 or 30 mg of Sildenafil (generic Viagra) be used as a PEM blocker? Or say 20 mg before exercise and 20 mg after? Just throwing it out there.
Yes, I know I am setting myself up for a few jokes.
Would you accept alcohol as an example?

I've tried doing exercise under the influence of alcohol, and the combination gave me extreme PEM. It is clear to me that any activity that asks my body for vasodilation causes PEM. (exercise followed by hot shower is also much worse for me than just exercise).

It is unclear if the problem is that the body can't vasodilate, or can vasodilate but then can't snap back to normal later. or maybe something else (can vasodilate, but at great cost?)

There are some studies on vasodilation in mecfs that suggest the former explanation: we can't vasodilate well. The norwegians find mecfs patients have "flow-mediated dilation" that operates with a score of 5.9 vs 7.7 in healthy controls. it's not a huge difference but statistically significant. they also did a different measurement of blood flow called post occlusive reactive hyperemia which seems to measure more peripheral blood flow and we were worse on that too.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8019750/

Scheinbenbogen herself has a small study and another small study that measure blood flow in patients, and finds problems. She measures reactive hyperemia, which I think is just cutting off blood flow to an area (say the hand) temporarily and then seeing how good the body is at refilling it with blood. It's unclear to me the extent to which that is really a measure of vasodilation. Anyway more me/cfs patients had low reactive hyperaemia:

"ED was defined by reactive hyperaemia index ≤1.81. Twenty healthy subjects of similar age and body mass index were used as a control group. Peripheral ED was found in 18 of 35 patients (51%) with ME/CFS and in 4 healthy subjects (20%, P < 0.05). Patients with ED, in contrast to patients with normal endothelial function, reported more severe disease according to Bell score."
 
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I'd also like to draw attention to a question asked by @HTester a while ago about whether we go red. going red is a sign your surface blood vessels have dilated.

https://forums.phoenixrising.me/thr...nd-body-temperature.82073/page-3#post-2311167

He asks if people "flush" . Several people said they do not.

I find this question hard to answer personally, as I just don't do any more the sort of things that would omnce have made me flush, like hard exercise in the heat. Is the capacity to vasodilate surface blood vessels still there? maybe, i did have a weird allergic response to something a few months ago that suddenly made me all red. If so, that would be a clue that vasodilation is possible, and a hint that perhaps it is just more costly for us.