Research news from Bhupesh Prusty

Copying the image from chillier's post with the fibronectin levels:

upload_2023-5-28_12-13-1-png.19614



From
Normal fibronectin levels as a function of age in the pediatric population
Normal adult serum fibronectin concentrations are typically 220 micrograms/ml +/- 20 micrograms/ml. Serum concentration is 35-40% lower than normal plasma concentration due to the binding of fibronectin to fibrin during clot formation.
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So, 220 ug/ml is a normal serum level for adults. From the charts, it is possible that there is a subset of people with ME/CFS and post-Covid fatiguing illness with higher fibronectin levels, although the mean for the healthy controls is perhaps lower than normal. Maybe the test was slightly different.

The chart separating out the levels by illness severity is quite interesting.

From
Plasma fibronectin in overweight men and women: correlation with serum triglyceride levels and serum cholinesterase activity
When compared with 67 age- and sex-matched normal weight control subjects, the 71 overweight patients displayed obviously higher levels of plasma fibronectin. For a similar body mass index (BMI) the 16 overweight men younger than 45 years had a significantly (P < 0.01) higher plasma fibronectin level (455 +/- 99.3 mg/l; mean +/- SD) than the 16 age-matched overweight women (351 +/- 105 mg/l) while there was no significant difference between the 22 overweight men (446 +/- 89.2 mg/l) and the 17 overweight women (475 +/- 111 mg/l) older than 45 years. Particularly high plasma fibronectin levels were noted in the five women with upper body (android) obesity. Plasma fibronectin was positively correlated with BMI, serum triglyceride concentration, plasma fibrinogen and serum cholinesterase activity. It is considered that metabolic disturbances related to upper body obesity may lead to an enhanced hepatic secretion of VLDL and of several plasma proteins including fibronectin.
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That paper (note it is talking about plasma not serum) does not seem to support the presence of the sex difference that Prusty is reported to have mentioned. Furthermore, it suggests that there might be a link between obesity and fibronectin levels. In that case, it perhaps would not be surprising that a higher percentage of people with a disease that limits activity would be obese, and would therefore show higher levels of a molecule associated with obesity.

from
Plasma Fibronectin Concentration A Risk Factor for Arterial Thrombosis?
There is a considerable range in fibronectin concentrations in the adult population, with a tendency for the concentration to be higher in men than in women, increase with age, and increase in the presence of malignancy or inflammation
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So, that paper also is not supporting the idea of higher levels of fibronectin in the serum of healthy women (vs healthy men).

So, I think it is possible that serum fibronectin levels might tend to be higher in people with ME/CFS and ME/CFS-like Long Covid. Whether that tells us anything useful about the underlying pathology, I don't know.

I'll be looking hard at the demographic information given for the samples in Prusty's paper, to see if there were differences in BMI, age and co-morbidities. And also looking for some very convincing support for his contention that fibronectin serum levels are higher in healthy women than healthy men, as my preliminary googling didn't support that.
 
Jonathan Edwards said:
Fibronectin is the molecular that sticks to anything, so the perfect candidate for giving spurious results.
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Fair point.

OTOH, given the apparent global effects in ME then whatever the underlying problem/process is in ME there is a real possibility that it involves something that is at least relatively widespread throughout the body, if not ubiquitous.

My particular interest is what, if any, mechanical effects could be produced, and hence be measurable, at the micro and/or macro level? Has there been a change, albeit subtle, to how the body handles both static and dynamic, and passive and active, mechanical forces?

It could explain why we are not finding many other consistent results, because so far they are all various secondary consequences of the body trying to function and maintain homeostasis under abnormal mechanical load conditions.

The reported changes to hemodynamics in at least a lot of patients might be a clue, for example. The problem may not be with the structures and processes of healthy hemodynamics, but that what they are being asked to do is outside their normal sustainable operating parameters.

If fibronectin is not sticking in its normal way, i.e. its mechanical characteristics have changed to an abnormal state, then what would be the consequences of that?
 
AknaMontes said:
Sad that IVIG seems to be his suggested treatment, as it is impossibly expensive for almost everyone and I cannot imagine the NHS managing to provide it for even a tiny number of those in the UK with ME and LC.
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IVIg has been used for all kinds of ailments. I would suspect that in a clinical trial setting, unless you have very good reasons to try that, and unless you have objective trial endpoints (bio markers), that there are little chances that we’d go anywhere with it. It would also fail at randomized, placebo controlled.
 
Milo said:
unless you have objective trial endpoints (bio markers), that there are little chances that we’d go anywhere with it. It would also fail at randomized, placebo controlled.
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Assuming there was sufficient evidence to warrant trialling, could the following work?

One third receive the presumptively active IgM-enriched immunoglobulins (eg Pentaglobin), one third receive standard IgG as a "theoretical placebo", one third receive saline or whatever appropriately approximates the other two as an actual placebo.

Objective biomarkers could include anything from 6 minute walk, cerebral perfusion drop on standing/tilt, daily actigraphy, or even CPET. Markers relating to coagulation and cytokines would be useful to compare between the two Ig groups, plus placebo. Potentially cytology of monocytes and NKs. Appropriate questionnaires for patient-reported outcomes would round it out.
 
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Sean said:
My particular interest is what, if any, mechanical effects could be produced, and hence be measurable, at the micro and/or macro level? Has there been a change, albeit subtle, to how the body handles both static and dynamic, and passive and active, mechanical forces?
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I have no idea whether there is any real basis for any of the talk about fibronectin here but I don't think it has any mechanical implications. We are talking about fluid phase chemical interactions in lab dishes with IgM or complement or whatever. If that had any knock on effects sufficient to change mechanics it would have been noticed and measured years ago. If anything the presentation would be expected to be like veno-occlusive disease or atherosclerosis and nothing like that has been described in ME.

The problem is that you can string body chemicals together in a story pretty much like you can string letters together to form words - however you like - without any reference to reality. Moreover, the stories that people come up with are always the same old ones that don't really make any sense in terms of what we know clinically.

I cannot see any point in discussing this sort of stuff unless we have some clear data. A vague story about IgM antibodies does not sound like it will go anywhere to me.
 
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My impression is that what is being proposed is a kind of immune defect resulting from insufficient integration of fibronectin into immune complexes (complement?).

I don't think he is saying that higher circulating fibronectin is causing problems.

I still don't have a good understanding of his ideas though and am going from memory at the moment.
 
strategist said:
My impression is that what is being proposed is a kind of immune defect resulting from insufficient integration of fibronectin into immune complexes (complement?).
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But where does that take us?
What would be the upshot of such an immune defect - further viral activity?
As far as I am aware fibronectin is not a critical factor in binding of antibody and complement to viruses.

As an immunologist I don't see any coherent story here. And I have yet to see any data that might justify even creating a story.
 
Let's hope the preprint of the paper is published soon. I'm not even going to try to rewatch his Berlin conference talk or listen to this latest lengthy podcast until we have his data and some expert comment. Until then it's like trying to find the way through fog. Better to wait for the fog to clear.
 
SNT Gatchaman said:
Objective biomarkers could include anything from 6 minute walk, cerebral perfusion drop on standing/tilt, daily actigraphy, or even CPET. Markers relating to coagulation and cytokines would be useful to compare between the two Ig groups, plus placebo. Potentially cytology of monocytes and NKs. Appropriate questionnaires for patient-reported outcomes would round it out.
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Your first sentence describes objective measurement but either are non-specific to ME or have not been validated and accepted as of yet as being sensitive and specific to ME (in the case of cerebral perfusion). As for cytology of monocytes and NK cells, we have no definitive answers, either because it is too early to get this established, because the studies are very small and not clear cut with good sensitivity and specificity and also because there are contradicting studies in the case of NK cells. I will leave the coagulation and cytokines alone. There has not been any study on coagulation for ME patients it has simply not been on the radar at all until very recently. We need to hear from different teams in that regard.


What’s left is the patient-reported outcomes, which are very tricky and often time misleading. There is so much work that needs to be done.

When I said objective biomarker, I had in mind an objective measure of illness like when you measure the size of a tumour or a lymph node on imaging, before and after treatment. something in the blood that is present when sick and absent when recovered. We still don’t have that.
 
Why would objective measures have to be specific to ME? Can they not be part of the ME picture, established to be seen in well characterised ME patients, even if some may also be seen distributed around various other conditions?

Eg for the cerebral blood flow question, yes a significant drop with orthostatic challenge might also be seen in heart failure or diabetic autonomic neuropathy, but it's not seen in normal people. If that were to normalise and the patient's self report is "no longer dizzy on standing", I would have thought that was supportive evidence that the drug had done something useful. In which case it might be informing elements of the mechanism.

I agree an ML model of 20+ cytokines does not make a specific biomarker, despite the number of LC papers we see proposing this, but if they normalise, isn't that evidence of recovery from the pathological state?

But if a specific objective marker is required, then in the absence of an established mechanism and related blood biomarker, as far as I've seen a deteriorating 2-day CPET has a lot of evidence of being highly specific to ME (although of course has risks). Maybe something like Maureen Hanson's "flat" urinary metabolome following 1x moderate exercise challenge could work as a light version?
 
I think for diagnosis a disease specific biomarker would be great. For a clinical trial comparing outcomes with and without the drug and unblinded the objective outcome doesn't have to be disease specific but does need to be clinically significant, ie showing a real sustained and sustainable improvement in function and reduction in symptoms.
 
Trish said:
I think for diagnosis a disease specific biomarker would be great.
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I'd even be happy with a non-disease specific one! Which might be more likely in the scheme of things.

There seem to be other instances of this, where X result = Y or M or B, and very occasionally F. There then has to be further refinement based on the signs and symptoms to decide which, but it can still be reliable.

Even if ME shared a biomarker with a dozen different conditions, it'd radically improve participant selection for trials. At the moment it's really difficult, especially as researchers want to be able to compare their results with earlier studies, so we get the out of date case definitions being used.
 
I missed recent updates, including the wise suggestion lfrom @Trisha to wait until the paper is published. I'd already written some comments after watching watched the video, so here goes.

It was interesting that Bhupesh Prusty started off by saying he believed herpesviruses are the core explanation of postinfectious ME.  The aim of this work was to demonstrate how this might work.

Exhibit one – evidence for reactivation of herpesviruses in ME/CFS.

When these viruses reactivate, they produce a key enzyme called dUTPase. ME/CFS patients showed higher levels of antibodies against Epstein-Barr virus, herpes simplex virus and HHV-6 dUTPases than didhealthy controls. BP said this was evidence of recent herpesvirus activation.

Note, this is not evidence that these viruses are currently active, though it makes it more likely.

Exhibit two – herpesvirus dUTPase can have a negative effect on mitochondria.

Other work by BP has shown that Epstein-Barr virus dUTPase causes mitochondria to fuse together and reduces their ability to fragment and then reform (continually  fusing and fragmenting a sign of healthy mitochondria and can help fight viruses).

Crucially, dUTPase also reduces oxidative phosphorylation, so could lead to less energy production from mitochondria.

No evidence was presented that this is happening in ME/CFS. And the IgG fraction work discussed later suggests mitochondria are more likely to fragment than, fuse.

Exhibit three – something in the blood

The lab separated the IgG fraction from patient blood. They tested this on a variety of cells and BP showed the results from testing on human umbilical endothelial cells. (Apparently these were the most interesting results).

Rather than the fusion shown by dUTPase, the cells treated with the patient IgG fraction showed excessive fragmentation.

And it was "pathogenic" – ie different from the fragmentation happening with healthy mitochondria.

However, it wasn't clear how this might lead to clinical effects, though it's an interesting finding.

Another biomarker claim.

They used mass spectrometry to analyse the IgG fraction, and demonstrated it contains other proteins that bind to the IgG complex, notably a molecule called Fibronectin1.

Fibronectin1 bound to IgG was depleted in the IgG fraction of ME patients, though it is high in their serum.

PB argued that Fibronectin1 could be a biomarker.

It does a poor job of separating oh ME patients from  healthy, controls (AUC=0.67, 0.5 is no better than a Coin Toss).

However, the results were stronger (AUC= 0.8), though not spectacular for severe ME patients compared with healthy controls.

I find this unconvincing, because the severe patients had a Bell score of 20/100 or less. It's hardly surprising that such sick patients are different from healthy controls

We need not only replication but also, as for any putative biomarker, comparison with disease controls.

Fibronectin 1 seems to be a multipurpose molecule, and it’s not clear how it would link to ME.

There was also some work on antibodies and autoantibodies, but the findings seems rather vague to me.

Not convinced

Maybe I'm missing something, but I can't see a logical chain that leads from herpesviruses to ME/CFS. Perhaps the missing links will be added at some point.
 
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Simon M said:
I missed recent updates, including the wise suggestion lfrom @Trisha to wait until the paper is published. I'd already written some comments after watching watched the video, so here goes.

It was interesting that Bhupesh Prusty started off by saying he believed herpesviruses are the core explanation of postinfectious ME.  The aim of this work was to demonstrate how this might work.

Exhibit one – evidence for reactivation of herpesviruses in ME/CFS.

When these viruses reactivate, they produce a key enzyme called dUTPase. ME/CFS patients showed higher levels of antibodies against Epstein-Barr virus, herpes simplex virus and HHV-6 dUTPases than didhealthy controls. BP said this was evidence of recent herpesvirus activation.

Note, this is not evidence that these viruses are currently active, though it makes it more likely.

Exhibit two – herpesvirus dUTPase can have a negative effect on mitochondria.

Other work by BP has shown that Epstein-Barr virus dUTPase causes mitochondria to fuse together and reduces their ability to fragment and then reform (continually  fusing and fragmenting a sign of healthy mitochondria and can help fight viruses).

Crucially, dUTPase also reduces oxidative phosphorylation, so could lead to less energy production from mitochondria.

No evidence was presented that this is happening in ME/CFS. And the IgG fraction work discussed later suggests mitochondria are more likely to fragment than, fuse.

Exhibit three – something in the blood

The lab separated the IgG fraction from patient blood. They tested this on a variety of cells and BP showed the results from testing on human umbilical endothelial cells. (Apparently these were the most interesting results).

Rather than the fusion shown by dUTPase, the cells treated with the patient IgG fraction showed excessive fragmentation.

And it was "pathogenic" – ie different from the fragmentation happening with healthy mitochondria.

However, it wasn't clear how this might lead to clinical effects, though it's an interesting finding.

Another biomarker claim.

They used mass spectrometry to analyse the IgG fraction, and demonstrated it contains other proteins that bind to the IgG complex, notably a molecule called Fibronectin1.

Fibronectin1 bound to IgG was depleted in the IgG fraction of ME patients, though it is high in their serum.

The suggestion was that Fibronectin1 could be a biomarker.

It does a poor job of separating oh ME patients from  healthy, controls (AUC=0.67, 0.5 is no better than a Coin Toss).

However, the results were stronger (A U,C= 0.8), though not spectacular for severe ME patients compared with healthy controls.

I find this unconvincing, because the severe patients had a Bell score of 20/100 or less. It's hardly surprising that such sick patients are different from healthy controls:we need not only replication but also, as for any putative biomarker comparison with disease controls.

Fibronectin 1 seems to be a multipurpose molecule, and it’s not clear how it would link to ME.

There was also some work on antibodies and autoantibodies, but these seems rather vague to me.

Not convinced

Maybe I'm missing something, but I can't see a logical chain that leads from herpesviruses to ME/CFS. Perhaps the missing links will be added at some point.
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Thank you Simon, this is really helpful.
 
Thanks, @Trish @Tia. It’s good to hear that these commentaries help.

But to a large extent, I write them to help me get things straight in my own mind. Often, when I first try to explain something, I realise I haven’t understood the situation properly myself.

ADDED
Einstein is supposed to have said, “You don't really understand something unless you can explain it to your grandmother.”
My aim is actually to explain things to people who are smart without having a huge amount* of science. But I think it’s true that attempting explanations can really find you out.

*okay, on forum posts I do assume quite a bit of science.
 
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