Preprint Indistinguishable mitochondrial phenotypes after exposure of healthy myoblasts to myalgic encephalomyelitis or control serum, 2025, Ryback et al

[chillier]

Indistinguishable mitochondrial phenotypes after exposure of healthy myoblasts to myalgic encephalomyelitis or control serum

Audrey A. Ryback, Charles Hillier, Camila M Loureiro, Chris P Ponting, Caroline F Dalton

Myalgic Encephalomyelitis (ME)/Chronic Fatigue Syndrome is a disease of uncertain aetiology that affects up to 400,000 individuals in the UK. Exposure of cultured cells to the sera of people with ME has been proposed to cause phenotypic changes in these cells in vitro when compared to sera from healthy controls. ME serum factors causing these changes could inform the development of diagnostic tests. In this study, we performed a large-scale, pre-registered replication of an experiment from Fluge et al (2016) that reported an increase in maximal respiratory capacity in healthy myoblasts after treatment with serum from people with ME compared to serum from healthy controls. We replicated the original experiment with a larger sample size, using sera from 67 people with ME and 53 controls to treat healthy cultured myoblasts, and generated results from over 1,700 mitochondrial stress tests performed with a Seahorse Bioanalyser. We observed no significant differences between treatment with ME or healthy control sera for our primary outcome of interest, oxygen consumption rate at maximal respiratory capacity. Results from our study provide strong evidence against the hypothesis that ME blood factors differentially affect healthy myoblast mitochondrial phenotypes in vitro.

Link: https://www.biorxiv.org/content/10.1101/2025.06.03.657595v1

 

[ME/CFS Skeptic]

Sad that that this paper couldn't find the same result of 'something in the blood' but good that they checked anyway.

 

[Jonathan Edwards]

Sad that that this paper couldn't find the same result of 'something in the blood' but good that they checked anyway.

Not at all sad, I would say. It is part of making sense of things - some of which were not making a lot of sense previously.

 

[jnmaciuch]

Thanks to the authors for the incredible amount of work that went into this study

A further limitation of our study is that participants with ME may not have been experiencing post exertional malaise (PEM) on the day of sampling. Participants had to travel to the university site to donate a blood sample, and due to ethical concerns around inducing crashes, we encouraged participant to re-schedule if they were not able to attend the site on that day. If ME-biased factors are episodic in people with mild and moderate ME, and only present when they experience PEM, in contrast to people with severe ME where they are present all the time, it could explain the difference in findings between this study and Fluge et al (2016).

This detail would have been my first thought about the discrepancy between findings. It is extremely admirable to have this level of consideration for participants, though it is a shame that it might skew the ability to replicate findings in this way.

Is there any study that collected blood from severe patients through home visits?

 

[Utsikt]

This detail would have been my first thought about the discrepancy between findings.

But why would these «episodic factors» only be present when in PEM in mild/moderate, but always present in severe/+ even when not in PEM?

 

[SNT Gatchaman]

Severe might simply equate to being in constant PEM.

 

[jnmaciuch]

But why would these «episodic factors» only be present when in PEM in mild/moderate, but always present in severe/+ even when not in PEM?

As just one example, it's what I would expect if the disease were driven by something being produced constantly in the tissue, and that production gets amplified during PEM. In mild/moderate, it may only reach the circulation when it is amplified during PEM. But severity may be correlated with how much is being produced in the tissue at any given moment, and a high enough level might be more likely to leak into the circulation.

That's just my pet theory, though. Could also be that severe was more likely to be in PEM just from participating in Fluge's trial

[Edit: cross-posted that last thought with @SNT Gatchaman]

 

[Utsikt]

Severe might simply equate to being in constant PEM.

My n=1 is that it isn’t. It can very easily be if you don’t have enough help, but that is a different issue.

 

[Utsikt]

As just one example, it's what I would expect if the disease were driven by something being produced constantly in the tissue, and that production gets amplified during PEM.

But wouldn’t symptoms severity correlate with this something in the blood? I had far worse symptoms when in PEM when moderate than what I have when severe and not in PEM. PEM when severe is even worse again.

 

[V.R.T.]

My n=1 is that it isn’t. It can very easily be if you don’t have enough help, but that is a different issue.

Maybe it isn't constant PEM per se but there is always something holding me back and slowing down/disordering my movements now that was only present during my worst crashes when mild/moderate.

Like gravity has been turned up or I'm wading through treacle.

That's not PEM as such but it is something that is constantly 'switched on' now that wasn't before I became severez and only showed up in and around crashes.

 

[Utsikt]

Maybe it isn't constant PEM per se but there is always something holding me back and slowing down/disordering my movements now that was only present during my worst crashes when mild/moderate.

Like gravity has been turned up or I'm wading through treacle.

That's not PEM as such but it is something that is constantly 'switched on' now that wasn't before I became severez and only showed up in and around crashes.

I also have things that are more constant when severe, that were not there when moderate and not in PEM, but I also have things that are not present when severe, even when in PEM, that were present when moderate. It keeps changing, and I have no idea of knowing if it’s just correlated with severity or if it’s caused by the severity.

 

[jnmaciuch]

But wouldn’t symptoms severity correlate with this something in the blood? I had far worse symptoms when in PEM when moderate than what I have when severe and not in PEM. PEM when severe is even worse again.

Not necessarily, if it is something triggered by activity itself which creates that amplified response. Severe would have higher baseline (high enough to have a physiological effect in the serum, anyways), and would be expected to increase in PEM as well.

Theoretically, if you compared serum levels between now and when you were moderate, you'd find that baseline levels are higher at severe, but "PEM" levels were actually higher in moderate [edit: than at severe baseline]. If this theory holds any water, that is. [Edit: That's why I'm really eager to get funding for some home visits to actually test it out]

[Removed some sentences where my wording was just really confusing. Apologies, bad brain fog atm]

 

[Utsikt]

Theoretically, if you compared serum levels between now and when you were moderate, you'd find that baseline levels are higher at severe, but "PEM" levels were actually higher in moderate. If this theory holds any water, that is.

So essentially like this mockup?

 

[jnmaciuch]

So essentially like this mockup?

Exactly! Thanks--I think my words were failing me initially, a graph might be better for getting the point across. Excuse all the edits on my last post, tried to go back and make it more coherent.

 

[Sean]

Doesn't matter if they found something or not. What matters is if they got the correct answer.

A robust negative result is just as valuable and valid as a robust positive result.

We do not want to waste time and resources pursuing false leads.

 

[hotblack]

Is there any study that collected blood from severe patients through home visits?

Plenty of us have given samples to the CureME biobank but I’m not sure how these samples being frozen would impact things? Anyway they’re doing free samples for researchers atm

My n=1 is that it isn’t.

Make that n=2

 

[hotblack]

The study has almost as many severe patients as Fluge et al 2016 (5 out of 67 versus 6 out of 12). They’re being very fair in their stated limitations but the sample size is so much bigger..
But the difference in cohorts is interesting. I wonder what it would look like comparing data from just the more severe with HC?

edit: oh they did that I’m going to be quiet until I can get through the whole paper!

 

[chillier]

Sad that that this paper couldn't find the same result of 'something in the blood' but good that they checked anyway.

We would have liked to a see a positive result obviously but what we really wanted was to get a clear answer about whether the 'factor in blood' work done previously was real. It's been an unresolved question for quite a while now and we thought we and the community deserved to know. We put a lot of emphasis on making sure the methodology was as ironclad as we could make it and we feel the finding is pretty solid.

 

[chillier]

The points raised about PEM and severity are the biggest limitations I completely agree. All the participants had to have been well enough to physically attend the university, but this doesn't mean they weren't very sick. The complete lack of any even incremental trend towards increased OCR in the ME group overall or after breaking down by severity suggests to me that this is not going to be a meaningful part of the biology in ME.

That doesn't necessarily mean there aren't differences in the blood detectable in other ways though.

 

[butter.]

The points raised about PEM and severity are the biggest limitations I completely agree. All the participants had to have been well enough to physically attend the university, but this doesn't mean they weren't very sick. The complete lack of any even incremental trend towards increased OCR in the ME group overall or after breaking down by severity suggests to me that this is not going to be a meaningful part of the biology in ME.

That doesn't necessarily mean there aren't differences in the blood detectable in other ways though.

Could you test severe ME patients using the same methodology, or are there any hindrances like pre-analytical stuff like handling and processing in time etc? Could you do sample acquisition in the home setting of severe patients? Thank you!