Substrate utilisation of cultured skeletal muscle cells in patients with CFS, Tomas et al, 2020

<sigh>

 

It would be useful to know how many were female - other studies have flagged up a propensity for females to switch to aminos in preference to fat .

Also AMPK is a key signalling molecule which seems to have many functions , it modulates metabolism in many conditions including diabetes , affects clock genes and could kick off a cascade of other feedback loops via purinergic signalling (?) .
Exploring its role in ME in more detail may elicit other mechanisms

 

Thanks @Midnattsol .
I wondered if the lack of ATP upstream caused a mitochondrial feedback loop.
One complex is overproducing because the other is under producing .

 

Revisiting the study titled Metabolic profiling indicates impaired pyruvate dehydrogenase function in myalgic encephalopathy/chronic fatigue syndrome

I think this is entirely consistent with my experience of having to eat often throughout the day and craving carbs, getting a short energy boost from eating, benefitting somewhat from acetylcarnitine, as well as being capable of exerting strength but having problems with endurance.

If PDH is impaired, it means each unit of glucose yields less ATP than normal. So you have to eat more than normal.

Acetylcarnitine helps the body utillize fats as fuel.

The endurance problem is a mix of inefficient use of glucose and rapid lactic acid accumulation.

 

This fits with my experiences too. My partner spotted that my appetite has changed since getting ME, and I agree.

 

Diet and custom made formulas based on my test results didn't prevent or correct the problem. Yes, deficiencies can be corrected with supplementation, but it doesn't address the underlying pathology.

 

Agree 2A,E would make more sense to me as well, could be a typo.

Does anyone know if someone has tried to replicate these results?

 

I've always eaten a high protein diet. I feel better/stronger with a protein rich diet from meat products, but my amino acid test indicated low/poor values.

 

Something to add to the previous post.

Acetyl-CoA is neded to run the TCA cycle and produce energy (it's one of several energy production systems). Acetyl-CoA can be obtained either from glucose, from fatty acids, or from ketone bodies (acetoacetate, beta-hydroxybutyrate, acetone), or from some amino acids.

The pyruvate dehydrogenase impairment would limit the production of acetyl-CoA from glucose but not from other sources.

Fluge et al 2016 found that the relevant amino acids were reduced which could indicate that they're being used more than normal.

Some other studies found that carnitine was reduced. Carnitine is primarily used to transport fatty acids into mitochondria.

Maybe ME/CFS patients are relying more on non-glucose sources of energy.

It seems plausible that some combination of interventions like carnitine supplementation, a high fat diet, high amino acid diet, ketone or specific amino acid supplementation might help, but it needs to be tested. Anecdotally not everyone is going to be able to tolerate carnitine or specific diets.

The reported association between ME/CFS and mutations in the Ornithine Transporter type 1 gene could be important here as well.

 

Mutations affecting the Ornithine Transporter type 1 could be making this situation of having impaired pyruvate dehydrogenase worse. Two ways I can think of:

First, this protein transports ornitine, and lysine and arginine into the mitochondria. Lysine and arginine are two of the several amino acids that feed the TCA cycle without passing through a pyruvate step. If a mutation reduces the transport of lysine and arginine into mitochondria then it would interfere somewhat with the metabolic adaptation to an impaired pyruvate dehydrogenase.

Second, if the mutation affects the urea cycle then it could lead to higher ammonia levels as the ammonia resulting from protein breakdown can't be disposed of as easily (although anecdotally patients seem to generally do better with a high protein diet).

@Simon M has written a short article on this https://mecfsresearchreview.me/2018...on-of-dna-variants-with-self-reported-me-cfs/ He thinks that this would result in increased ornithine, which two studies have found but a third found lower levels.

Similarly, one would expect that additional problems that interfere with other kinds of metabolic adaptations to make the problem also worse. For example, a researcher recently said that in some patients oxidation of fats was also not working well (if I remember right). This could be a big problem because glucose and fatty acids are our main source of energy.

 

There is a good summary of this study by ME Research UK (who were the funders):
https://www.meresearch.org.uk/resea...CIkMUB--X9qdbtluU7HDTFsnMb4oqG__zSfIeBp4D7MqQ

The MERUK summary concludes:

 

Oligomycin is a Complex V inhibitor. When it is injected during a seahorse assay, the OCR is expected to drop. This drop (oligomycin-sensitive component) reflects the OCR by Complex V and thus is a measure of ATP synthesis rates. The value plotted is typically the result of the following: "ATP synthesis = basal OCR - post-oligomycin OCR". So yes the units are appropriate. Hope this helps.

 

Correct, and this is a clever analogy .

In general (not just necessarily in the context of ME/CFS) I think this is possible if something is wrong with the Complex V machinery itself (we don't know if this is the case or not in ME/CFS). But I think this would be pretty apparent and accompanied by other abnormalities, and so shouldn't confound anything - you would note it and look for how it is occurring. Plus, severe (eg: genetic) issues with Complex V are often lethal or present from birth.

We speculated what the cause of inefficient ATP synthesis in lymphoblasts could be, based on our knowledge at the time in our first ME/CFS study: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7036826/ , paragraph starting with "What might cause such a mitochondrial Complex V inefficiency?". Sorry if this is a hassle to read, it felt like bad etiquette to paste in a text block of my own findings in a thread about somebody else's research. Anyway, the tldr is: a mutational defect seems less likely than dysregulation.

Off the top of my head... we have measured it by luciferase luminescence, and so have Lawson et al 2016. But these were steady-state measurements of ATP levels, not sure if other techniques measuring the rate of ATP synthesis have been employed. I might be forgetful though. Vermeulen et al 2010 also measured it but the citation for their method is throwing up a dead end for me so I can't really comment. You are right, the findings do vary, but I think these can be explained by differences in cell/tissue type or methods employed, etc. Different-shaped pieces of the same puzzle.

Oxidisable substrate provision is relevant to the IACFS talk I just gave, the results from which are unpublished. I know Cort was covering the conference but not sure if he's written up anything that I spoke about yet. I did post a little about it previously but I don't want to discuss too much detail informally before it's all finalised. That discussion alongside our new results will be in everybody's hands in the future.

I can make a couple of observations more freely based on what is already published:

-this is another study showing no changes in the rate of glycolysis in seahorse, which is in line with lymphoblasts, PBMCs, NKs (sans glycolytic reserve). EDIT: another study showing reductions in glycolytic rate which I forgot to mention initially: https://pubmed.ncbi.nlm.nih.gov/31830003/

-Normal basal OCR and absolute rate of ATP synthesis, and elevated maximum OCR with galactose reported here, which for these parameters is the same pattern in lymphoblasts. Unchanged ROS, also the same as lymphoblasts. Glucose utilisation shows some differences in oxphos, but I need to think more about this. Could very well be an upstream defect as suggested. Glucose can also be increasingly or decreasingly utilised by the pentose phosphate pathway - this can also affect many relevant things such as redox balancing and pyruvate supply, which in turn affect mitochondrial function. Maybe another pathway to have a read about for you guys, if unfamiliar. I touched on it in the IACFS talk.

-Would be interesting to see how the cells use glutamine as well given previous metabolomic reports - through GDH and also through glutamate to aspartate (AST) - both routes assist with the provision of reducing equivalents (in different ways) to drive OXPHOS. There are other relevant amino acid degradative pathways (stay tuned) but glutamine is used the most by the cell, and has been discussed the most in the field.

-It is suggested that a metabolic inflexibility is present and lies outside of AMPK, since AMPK is proposed to behave normally. This is interesting since the chronically activated TORC1 signalling seen in lymphoblasts would likely contribute towards metabolic inflexibility. Different tissue types though, but interesting to think about.

 

Apologies if this sounds garbled ( and it could well be wrong ) , I looked at PPP some time ago when.looking at D Ribose as a means of reducing PEM.

Is the pentose phosphate pathway more energy intensive ? Ie net energy deficient and takes some time to generate ATP.

 

Sounds like you're thinking that TORC1 may be chronically activated in ME?

Fwiw, I'm a responder to rapamycin -- it has doubled my walking distance and diminishes and shortens my PEM.

 

The PPP is generally considered to support aspects of anabolic metabolism - that is it largely assists with the building of molecules such as adenine nucleotides and fatty acids. But it can also produce pyruvate, which can then be utilised to make energy. It also produces reducing equivalents.

So the answer isn't really simple, other than to say that it *can* constitute a roundabout way of contributing towards energy supply. The pathway has different arms that do different things. In terms of assisting with ATP supply you could consider it much less powerful than glycolysis or OXPHOS since it's doing lots of other things too, only some of which are more directly related to energy generation. These functions are also dependent on the tissue and metabolic requirements at the time.

We saw an elevation in steady-state TORC1 activity levels in lymphoblasts from ME/CFS patients, yes. But this will need to be followed up in other cell types and I certainly wouldn't want to advocate for using it to guide treatment yet. Still, I am glad that you've found something that works for you.

Don't want to distract the thread too much so I'll leave it there for now.

 

This fits with my experience pretty much spot on when I was still trying to function and keep going / working. The effort involved was immense which made me all the more angry when I read the GET deconditioning clap trap......

 

"The retention of bioenergetic defects in cultured cells indicates that there is a genetic or epigenetic component to the disease."

I just wanted to highlight this for consideration. I am not sure those are the only two options though. Signalling factors might still be present from before sample isolation.