Ponderings and speculations about purinergic signaling, in pursuit of a unified ME/CFS theory

[Hip]

One thing perhaps of relevance is that when I was experimenting with an ATP supplement called Peak ATP (which contains ATP in the form of its sodium salt, adenosine 5’-triphosphate disodium), I found 400 mg doses of this supplement had little or no effect on my ME/CFS symptoms. I am not sure what extracellular ATP levels are reached in the tissues after cell damage and rupture, but if supplementing with ATP can produce anywhere near comparable levels, then you might expect a significant worsening of ME/CFS symptoms as a result, if CD39 is indeed disabled.

I am thinking that it might be possible to use such an ATP supplement as a means to test the theory.

 

[Jesse2233]

@Hip do we know what sort of bioavailability such oral ATP supplements have?

 

[Hip]

@Hip do we know what sort of bioavailability such oral ATP supplements have?

Actually it looks like such ATP supplements are not orally bioavailable at all, according to this study, which found that ATP concentrations in blood did not increase after ATP supplementation using enteric-coated tablets (stomach acid breaks down ATP, which is why enteric tablets are used; but it seems that even with these, you don't get any ATP absorbed into the bloodstream). Oh well, so much for that!

 

[Jesse2233]

@Hip hmm seems an IV infusion / suppository would be a better test

To further complicate issues here's a study @pattismith unearthed on another thread that indicates concentration level and duration of eATP exposure play a role in how cells react

Extracellular ATP in the immune system: more than just a "danger signal".
Trautmann A1.

Abstract
Extracellular adenosine 5'-triphosphate (eATP) is ubiquitously used for cell-to-cell communication. The low concentration of eATP ([eATP]) that exists in a "halo" surrounding resting cells signals the presence of neighboring living cells. Transient increases in [eATP] are used for basic physiological signaling, namely, in the nervous and vascular systems. Larger increases in [eATP] that are associated with cell death serve as a key "danger" signal in inflammatory processes. Two studies now point to roles for ATP in the immune system: providing a costimulatory signal to T cells and driving the differentiation of intestinal T helper 17 (T(H)17) cells.

 

[nandixon]

So the three possibilities are:

1. Not enough Tregs positive in CD39 and CD73 are being produced.
Not all Tregs express CD39, only a specific CD45RO+CCR6+ effector/memory-like subset of them, also called TREM. Interesting observations have been made in multiple sclerosis, where the overall number of Tregs was not much different from controls, but the amount of Tregs positive in CD39 was much lower in MS patients.[source] It is possible that a similar thing is happening in ME/CFS, perhaps by a different mechanism.

Good work @necessary8. I can't think of any inconsistencies with existing ME/CFS studies with your idea of there being some sort of CD39 deficit present. I still need to look at whether it can be determined if a CD39 issue is more likely to be upstream or downstream of one or two other possibilities, though.

In the meantime, has no one yet cited the ME/CFS studies where CD39 was looked at? There are at least two from Brenu et al (Marshall-Gradisnik’s group). Both appear to be consistent (or not inconsistent) with your hypothesis, I think. (There may be others.)

First study (2013):
Immune Abnormalities in Patients Meeting New Diagnostic Criteria for Chronic Fatigue Syndrome/Myalgic Encephalomyelitis

Second study (2013/2014):
Role of adaptive and innate immune cells in chronic fatigue syndrome/myalgic encephalomyelitis

(Full text for the second study is here.)

 

[Marco]

Second is the connection to the brain. In the nervous system eATP is a neurotransmitter. It also activates microglia, which are basically the nervous system's macrophages. Jarred Younger's research points to microglia activation in ME/CFS and it could also explain some, or all, of our neurological symptoms, as well as the common dysautonomia. There could also be a feedback loop in here.

Third is the connection to exercise and PEM. The exacerbation of symptoms after exercise is a very distinct, hallmark symptom of ME/CFS and is the main thing that makes ME/CFS such a disabling condition. I have yet to see a plausible biochemical model of PEM, and I believe this is a compulsory requirement for any general theory of ME/CFS. The delayed nature of PEM and the fact that mental exercise can also cause it, can be important clues to what it is biochemically.

Interesting to note perhaps that both 'exemplary' PAMPs https://www.frontiersin.org/articles/10.3389/fimmu.2015.00422/full ATP http://www.brainimmune.com/innate-i...l-stress-atpp2x7r-inflammasome-nlrp3-cascade/ and HMGB1 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4508196/ are increased during psychological stress.

HMGB1 is a 'late' inflammatory mediator with peak levels occurring 8-72 hours (eta after the 'insult').

 

[Hip]

It's interesting that the P2 family of receptors are implicated in neuropathic pain: I wonder if this could explain (at least in part) the joint and muscle pain (myalgia) that can be found in ME/CFS?

See:
The role of P2X7 in pain and inflammation
P2 receptors and chronic pain

 

[Philipp]

Actually it looks like such ATP supplements are not orally bioavailable at all, according to this study

I don't understand this topic at all so I do not know if it is worth bringing this up, but someone who is selling this stuff claimed elsewhere:

Previous research has led people to believe that adenosine triphosphate (ATP) is not orally bioavailable, thus dismissing its use as a sports supplement. While the research itself was not inherently incorrect, it turns out researchers were just measuring ATP at the wrong place (they should have been measuring venous portal blood).

He cited https://www.ncbi.nlm.nih.gov/pubmed/21129239 as another example for research finding no bioavailability, and https://www.ncbi.nlm.nih.gov/pubmed/15179168 & https://www.ncbi.nlm.nih.gov/pubmed/24330670 as examples for research showing mild ergogenic benefits, but provided no citation as to how he arrived at the '[...]should have been measuring venous portal blood' claim as far as I can see.

If these ergogenic benefits are not artifacts of the research settings, this may point to blood concentrations as measured in the study you cited not being as relevant as one would intuitively assume.
But like I said, I know nothing about the kinetics (and so on) of ATP and do not know how one would go about legitimately extrapolating the effects of externally sourced ATP to those of the eATP that might be relevant for us.

 

[Hip]

@Philipp, the Peak ATP study I cited above suggested that the ergogenic benefits of this supplement may be due to the fact it converts to uric acid, which may have ergogenic itself. They found that uric acid levels in the blood were increased after Peak ATP supplementation.

 

[voner]

It's interesting that the P2 family of receptors are implicated in neuropathic pain: I wonder if this could explain (at least in part) the joint and muscle pain (myalgia) that can be found in ME/CFS?

See:
The role of P2X7 in pain and inflammation
P2 receptors and chronic pain

@Hip, thanks for the post. here is another and more recent paper by the same author, Kazuhide Inoue......

Purinergic signaling in microglia in the pathogenesis of neuropathic pain

 

[Hip]

@necessary8, do you think your theory would require a source of ATP from virally-ruptured cells in order to kick off the cascade of positive feedback that results in excess extracellular ATP? Or is simply having a faulty CD39 negative feedback loop enough to trigger this cascade?

Because I don't think much viral lysis (cell rupture) is going on in ME/CFS: in enterovirus-associated ME/CFS, much of the infection is an intracellular infection of non-cytolytic enteroviruses (which don't rupture and kill cells); and in herpesvirus-associated ME/CFS, Dr Lerner proposed that ME/CFS involved abortive herpesvirus infections (which are closely analogous to non-cytolytic infections, and also don't rupture and kill cells).

 

[Hip]

I found this paper, which contains a large list of natural compounds which have effects on P2 receptors. I have added some of these compounds to the list in my earlier post.

 

[Hip]

I have just determined that high dose magnesium injections, Emodin (from the herb Rheum palmatum), kaempferol (from canned capers), and possibly Brilliant Blue FCF are viable as orally administered inhibitors of Panx1, P2X7 and P2Y2. See this post and this post for details.

 

[Murph]

Back when Naviaux did his paper on the metabolic features of chronic fatigue syndrome (Dauer, worms, hypometabolism, etc) he released data on all the metabolites he found, at the metabolomics workbench.

At the time I dived in and tried to make sense of it all. If I know little about cellular biology now I knew even less then, but I know how to drive Microsoft Excel so I made a few tables and a few charts.

I decided to have a look back at my graphs and to see where ATP levels were at. It is, sadly, not found to be wildly out of line between patients and controls: levels in female patients were 97% that of female controls. (For some reason he measured it in women but not men).

(Patients at left, numbered; Controls at right labelled fctrl_0XX.) The variance is low and there's no clear pattern.

However, another purine was one of the clearest and most consistent results: adenosine.

(nicotinamide and continine were further out but showed *extremely* high variance and are related to nicotine, and I suspect smoking may explain them.) As you can see here adenosine levels were within a more narrow range and quite different on average between patients and controls. I haven't done p values on this but I guess I should.

Adenosine certainly has a range of interesting roles.

I'm personally always interested in vasodilation/vasocontraction problems (because of POTS, widespread problems with alcohol, the Fluge Mella NO patent, etc.). I think endothelial cells, being bloodflow facing immune signalling cells, are a perfect suspect that might decide to turn a local problem (lack of appropriate vascular tone) into a global one: an acute systemic immune response. Which could be a great explanation for PEM.

Adenosine is also tied up in metabolism, of course.

I'm certainly interested to hear if anyone can find any strong links from Adenosine to the puringeric signalling theory!

EDIT: this paper may be interesting:
Extracellular Adenosine-Mediated Modulation of Regulatory T Cells

 

[nandixon]

Nice @Murph - low adenosine is potentially good evidence for a CD39 problem. It also might suggest that a CD39 issue is actually upstream to Naviaux’ cell danger response (CDR) theory, at least in ME/CFS.

 

[dreampop]

I think my original comment was wrong, since it wouldn't matter what the ATP levels in the blood were.

 

[dreampop]

Since this is a thread about the purinergic receptors, I wanted to summarize 4 Alan Light studies that have keyed in on purinergic signalling.

• After a sustained moderate exercise test, CFS patients showed greater increases than control subjects in gene expression for metabolite detecting receptors ASIC3, P2X4, and P2X5, for SNS receptors alpha-2A, beta-1, beta-2, and COMT and IS genes for IL10 and TLR4 lasting from 0.5 to 48 hours (P < .05). (1997)

• Regression analysis predicting these biologic factors using FMS, CFS, depression...revealed that greater expression in factors 1 and 3 was positively associated with CFS and negatively associated with depression severity... but not associated with FMS. Factor 1 is purinergic and cellular modulators, factor 3 is nociception and stress mediators. (I wish I could read this whole study, 2016)

• CFS patients showed higher P2RX7 and lower HSPA2 versus controls and PCF [Androgen deprived prostate cancer patients]. Correlations with fatigue severity were similar in PCF and CFS for only DBI, the GABA-A receptor modulator (r=-0.50, p<0.005 and r=-0.34, p<0.05). (2013)

• Patients with CFS had greater postexercise increases in fatigue and pain and greater mRNA increases in purinergic type 2X4 receptor, transient receptor potential vanilloid type 1, CD14, and all adrenergic receptors than controls (mean ± standard error = 1.3 ± 0.14- to 3.4 ± 0.90-fold increase above baseline, p = .04-.005). (2012)

I thought it was interesting the P2X4 came up twice in exercise tests.

 

[Jesse2233]

@Murph nice! would be interested to see the P-value on adenosine for men and women

 

[Murph]

(I wish I could read this whole study, 2016)

 

[bertiedog]

I decided to have a look back at my graphs and to see where ATP levels were at. It is, sadly, not found to be wildly out of line between patients and controls: levels in female patients were 97% that of female controls. (For some reason he measured it in women but not men).

This isn't what Dr McClaren Howard who owns his own lab, Acumen, here in the UK has found. In the study between Dr Myhill, Dr Booth and McClaren Howard there was a very distinct lack of ATP available in the patients and this correlated more or less completely with the patients' symptoms. From memory the ATP was low even to start off with and things got worse as the process went on. He found that many patients had blockages in the energy pathways, with things like viruses, heavy metals and organophosphates showing up.

I watched an excellent You Tube video of Dr Myhill yesterday and she said regarding this study in effect it was blinded because she found the patients, Dr McLaren Howard didn't know whether the patients were mildly or severely affected, he just worked on their blood and Dr Booth independently put the results together not knowing any of the patients and their symptoms. Naturally Dr Myhill was delighted to see how the results confirmed to her the severity of her patients symptoms with differences between those who were mildly affected and those who were badly affected. I think there were around 70 patients and controls which I realise is a small study but it did have some interesting results.

Pam