Preprint Oxidative Stress is a shared characteristic of ME/CFS and Long COVID, 2024, Shankar, Bonilla, Davis et al.

Oxidative Stress is a shared characteristic of ME/CFS and Long COVID
Vishnu Shankar; Julie Wilhelmy; Basil Michael; Layla Cervantes; Vamsee Mallajosyula; Ronald Davis; Michael Snyder; Shady Younis; William H Robinson; Sadasivan Shankar; Paul Mischel; Hector Bonilla; Mark Davis

More than 65 million individuals worldwide are estimated to have Long COVID (LC), a complex multisystemic condition, wherein patients of all ages report fatigue, post-exertional malaise, and other symptoms resembling myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). With no current treatments or reliable diagnostic markers, there is an urgent need to define the molecular underpinnings of these conditions.

By studying bioenergetic characteristics of peripheral blood lymphocytes in over 16 healthy controls, 15 ME/CFS, and 15 LC, we find both ME/CFS and LC donors exhibit signs of elevated oxidative stress, relative to healthy controls, especially in the memory subset. Using a combination of flow cytometry, bulk RNA-seq analysis, mass spectrometry, and systems chemistry analysis, we also observed aberrations in ROS clearance pathways including elevated glutathione levels, decreases in mitochondrial superoxide dismutase levels, and glutathione peroxidase 4 mediated lipid oxidative damage.

Critically, these changes in redox pathways show striking sex-specific trends. While females diagnosed with ME/CFS exhibit higher total ROS and mitochondrial calcium levels, males with an ME/CFS diagnosis have normal ROS levels, but larger changes in lipid oxidative damage. Further analyses show that higher ROS levels correlates with hyperproliferation of T cells in females, consistent with the known role of elevated ROS levels in the initiation of proliferation. This hyperproliferation of T cells can be attenuated by metformin, suggesting this FDA-approved drug as a possible treatment, as also suggested by a recent clinical study of LC patients.

Thus, we report that both ME/CFS and LC are mechanistically related and could be diagnosed with quantitative blood cell measurements. We also suggest that effective, patient tailored drugs might be discovered using standard lymphocyte stimulation assays.


Link | PDF (Preprint: BioRxiv) [Open Access]

 

What is "over 16 healthy controls, 15 ME/CFS, and 15 LC" supposed to mean?

I haven't looked at the study at all but there is a large discrepancy between the sex ratios (HC: 46% female, ME/CFS: 77% female, LC: 53% female).

 

So what?

 

It might be of relevance since the authors report sex differences in their findings "Particularly striking was that only female patients had elevated ROS levels in ME/CFS and LC, together with the hyperproliferation of lymphocytes after stimulation in culture, whereas both sexes showed evidence of elevated levels of reduced glutathione and lipid oxidative damage." But like I've said I haven't even read the study yet.

 

Then maybe you could try to read it before you write?

 

It is very common on this forum for not everybody to have the energy and cognitive abilities to read every single study the moment it comes out. They way I've seen this forum work is that typically a bunch of different observations are made until more definite conclusions can be made.

Since you seem to be commenting on a study and demand that it must be read before doing so, can you explain which results might or might not be driven by general sex differences rather than health status (of course they looked at everything split into M and F as well but the sample sizes for that then might become less reliable even though some of the differences look striking in the graphs)?

 

I am not motivated to read further than the abstract here I am afraid. In the past an abstract was supposed to contain the highest concentration of hard numerical data you could fit in, with minimum of interpretation. The reader could do the interpreting. These days so many papers fill an abstract with speculative interpretation and no data at all. The overall impression is that a vast number of measurements have been made on a rather small sample and the few results that look as if they might support a theory are selected for that purpose.

 

Either I am getting the percentages wrong or there is something wrong about the data and sex ratios:

Sample sizes
16 HC (46.6% Female), 15 ME/CFS (76.9% Female), 15 LC (53.3% Female).

According to the plots 7 out of 16 HC’s are female, however 7/16 is not 46.6% but rather 43.75%, so this would appear to be a mistake (7/15=46.6% so that might have been the mix-up). I hope they didn’t work with this in their statistical analysis.

Similarly I don’t understand how 76.9% of ME/CFS patients could be females (12/15=80% and 11/15=73.3) and according to the plots it looks like it should only be 10 ME/CFS females.

For LC it is clear that 53.3% of LC patients being female would mean 8 patients which is also what the data shows.

I wonder, if they are indeed mistakes, who much these mistakes would influence the results. It's hard for me to understand how they could have gotten the sex ratios wrong in a study that is focused on finding sex differences in M/F, so I'm hoping there is an alternative explanation.

 

There's a lot in the paper and possibly you'd need 5 separate papers to have a comprehensive abstract with the summary data in each. There's a lot that's interesting about T cell proliferation scaling with oxidative stress. They suggest that T cells proliferate more readily and that leads to far greater energy consumption (and starvation for other systems). I haven't finished reading but I'd have to wonder if T cell proliferation during the follicular (proliferative) phase of the menstrual cycle may explain cyclical symptom increase.

Can I entice you with the following?

 

I apologise to you @EndME for not getting the purpose of this forum. And I also apologise for upsetting you.
Together with what @Hutan wrote I get it better now.

 

No problem. I think it's also fair to suggest that I should sometimes read more before commenting. Unfortunately, for this study, not even the reported sex ratios make any sense to me and that doesn't make me enthusiastic to spend my energy to dive further into it.

Being active on this forum one quickly comes to the realisation that the majority of studies are in fact not particularly interesting at all and especially when it comes to LC studies, 95% of the time it suffices to look at patient selection to understand that the study can be discarded as "not interesting at all" (which I'm not suggesting is the case here).

 

How much energy does it take for T cells to proliferate? It is plausible to suggest that the proliferation of a certain type of immune cell has a non-negligible impact on overall energy use? I have always found it hard to believe that this type of energy consumption could be anywhere near the energy required to move or think.

 

Not really. I have heard people burbling on about oxidative stress for about 45 years now and have not seen anything that suggests it is of any great relevance to anything.

If you have good quality data you can put them in an abstract. If you have too much data that usually means that you are using a scattershot approach and have no real idea why you are measuring. Important findings do not nee all these complicated subsidiary analyses.

The idea that somehow oxidative status should be crucial to T cell dysfunction is to me pretty implausible. Immunology turns on much more specific things by and large.

 

Indeed, the statement referred to seems excessively naive.

 

The references 18 and 19 are bot to some guy called Straub, probably a rheumatologist, who I have never heard of, claiming to be able to explain to the rest of physicians how to understand inflammatory disease in terms of energy balance. Nature Reviews Rheumatology is a fluff journal that takes anything that pays I think. I am pretty sure this is just some oddball's speculation.

And anyway none of this makes sense. When I go on a skiing holiday I probably increase my metabolic demand, with six hours maximal effort in freezing temperatures, by 50-70 or even 100%. I feel well exercised at the end of the day but I don't feel 'fatigued' in the sense that ill people do. Human beings can easily accommodate an extra 60% metabolic demand without feeling in any way unwell. The whole thing seems have been dreamt up by someone who has no real grasp of medical science.

If, in contrast, you inject a few micrograms of endotoxin into someone they will feel dreadfully fatigued despite not doing anything much And if you block TNF in RA fatigue melts away within a hour or so. Not a lot of time for proliferation there!

 

I agree with Jonathan i.e. Oxidative Stress has been claimed to be the cause of all manner of things. If it were true then I'm guessing that DecodeME would turn up clues e.g. genes liked to selenium. Also, rare genetic variant/whole genome sequencing (family) studies should identify cases. The other thing is that presumably there'd be clues re immunology - I vaguely remember something re this from my time as a laboratory technician -- 40 ish years ago!
EDIT - haven't read the paper!