Abnormalities of AMPK Activation and Glucose Uptake in Cultured Skeletal Muscle Cells from Individua

[Bob]

OK, so, looking for clues, what follows is a stream of (Bob's) consciousness (scary thought) based on my extremely basic (Wikipedia-based) knowledge... Join me if you're brave enough to follow my stream of consciousness...

If there is a build up of lactic acid, but little glucose metabolism, could this suggest a blockage in a metabolic process that affects both the metabolism of glucose and the conversion of lactic acid (i.e. an inability to process both glucose and lactic acid)?

The production of lactate is a beneficial process because it regenerates NAD+ (pyruvate is reduced to lactate while NADH is oxidized to NAD+), which is used up in oxidation of glyceraldehyde 3-phosphate during creation of pyruvate from glucose, and this ensures that energy production is maintained and exercise can continue.

http://en.m.wikipedia.org/wiki/Lactic_acid#Exercise_and_lactate

So this seems to indicate that there is a reverse metabolic process that involves both lactic acid and glucose: i.e. Lactic acid helps convert NADH to NAD+, which in turn helps convert glucose to pyruvate. (Unless I've misunderstood it.)

So could we have a problem converting NADH to NAD+? Which means that lactic acid isn't processed and that, in turn, glucose isn't converted to pyruvate? (Or have I completely misunderstood this metabolic processes?)

In metabolism, nicotinamide adenine dinucleotide is involved in redox reactions, carrying electrons from one reaction to another. The coenzyme is, therefore, found in two forms in cells: NAD+ is an oxidizing agent – it accepts electrons from other molecules and becomes reduced. This reaction forms NADH, which can then be used as a reducing agent to donate electrons. These electron transfer reactions are the main function of NAD. However, it is also used in other cellular processes, the most notable one being a substrate of enzymes that add or remove chemical groups from proteins, inposttranslational modifications. Because of the importance of these functions, theenzymes involved in NAD metabolism are targets for drug discovery.

http://en.m.wikipedia.org/wiki/Nicotinamide_adenine_dinucleotide

If there was a problem converting NADH to NAD+, then there may be an imbalance of NAD+ vs NADH within cells. How would this affect an organism?

There's more info about NAD+ and NADH here:
http://en.m.wikipedia.org/wiki/Nicotinamide_adenine_dinucleotide

The above quote refers to "redox reactions". If redox reactions are faulty, then a "redox state" can arise in a cell or organism. Wiki says:

The term redox state is often used to describe the balance of GSH/GSSG, NAD+/NADH andNADP+/NADPH in a biological system such as a cell or organ. The redox state is reflected in the balance of several sets of metabolites (e.g., lactate and pyruvate, beta-hydroxybutyrate, andacetoacetate), whose interconversion is dependent on these ratios. An abnormal redox state can develop in a variety of deleterious situations, such as hypoxia, shock, and sepsis. Redox mechanism also control some cellular processes. Redox proteins and their genes must be co-located for redox regulation according to the CoRR hypothesis for the function of DNA in mitochondria and chloroplasts.

http://en.m.wikipedia.org/wiki/Redox#Redox_reactions_in_biology

The above quote seems to confirm that the balance of lactate and pyruvate are influenced/determined by the balance of NAD+/NADH.

OK, that's as far as I've got for now. Should we be looking at the metabolic process involving NAD+/NADH, lactic acid, and glucose/pyruvate? Could there be something causing a blockage in this metabolic process? A faulty enzyme? A missing protein? An epigenetic issue? A virus?

 

[bel canto]

Lacking the biochem background to fully understand this discussion, I'm wondering whether levels of pyruvate (in urine) as measured by Metametrix would be higher or lower than expected. What about levels of the other metabolites mentioned? Thanks. I surely appreciate you all for these analyses!

 

[MeSci]

There's more info about NAD+ and NADH here:
http://en.m.wikipedia.org/wiki/Nicotinamide_adenine_dinucleotide

The above quote refers to "redox reactions". If redox reactions are faulty, then a "redox state" can arise in a cell or organism. Wiki says:

Thanks for the contributions, @Bob. My brain isn't yet in a state to take them in or think about them - will try later!

I think that 'redox state' just means the balance between oxidation and reduction, so it can describe any such balance, not a specific state.

I wonder if this paper from 2012 about mitochondrial abnormalities in ME by Myhill's team can throw any light on the current discussion.

 

[Bob]

More random ramblings about metabolic pathways (i really don't have any insight into this subject area - I'm just brainstorming - or braincrawling in my case)..

In organisms, NAD can be synthesized from simple building-blocks (de novo) from the amino acids tryptophan or aspartic acid.

http://en.m.wikipedia.org/wiki/NADH

I've heard the tryptophan pathway mentioned before in relation to ME/CFS. (Can't remember where.) If there were a problem converting tryptophan into NAD, then would there be a build up of aspartic acid and lactic acid in cells, and also an associated reduction in glucose metabolism? There are a number of metabolic pathways that create NAD, so if only one pathway were faulty it might explain why our cells can handle a certain amount of metabolism (i.e. at rest) but can't handle increased metabolism (i.e. increased exertion).

 

[adreno]

@Bob

@Kimsie has hypothesised about NAD in relation to ME, see for example:

http://forums.phoenixrising.me/index.php?threads/recipe-for-nad-and-atp.33962/
http://forums.phoenixrising.me/inde...ods-and-can-cfs-people-get-really-well.34385/

 

[Bob]

I think my previous two posts demonstrate that I know next-to-nothing about mitochondrial processes, metabolic pathways, the Krebs cycle, and ATP etc. It's exceptionally complex, and I have a basic school text-book understanding of this aspect of biology. It seems that there are myriad possibilities, in terms of what could go wrong in the metabolic pathways. I've got some reading to do!

 

[Bob]

Anyone interested in this thread may be interested in this:

In silico analysis of exercise intolerance in myalgic encephalomyelitis/chronic fatigue syndrome
http://forums.phoenixrising.me/inde...phalomyelitis-chronic-fatigue-syndrome.36750/

 

[MeSci]

I am also wondering about this. If (relatively) less glucose is absorbed, then why is lactate higher? It seems a contradiction. So maybe it wasn't higher in this test bed. Which raises questions about how much this might reflect in vivo muscle metabolism, that is how it works in the body.

I still have a lot of messages to read, and maybe these questions have been answered, but thought I'd post a link to this paper which is about how the body deals with lactate in health and disease, with some useful diagrams.

 

[MeSci]

As @nandixon says, AMP-K is active in other tissues, including the brain (they study doens't look at other tissues for comparison) and problems with AMP-K in the brain could explain problems with mental fatigue too. Interestingly, the finding of reduced IL-6 production by the muscle cells from CFS patients ties in with the low AMPK activation as IL-6 is an AMPK activator.

IL-6 is one of the cytokines that Hornig and Lipkin found to be increased in the first 3 years of ME and decreased in later years, compared to healthy controls.

I definitely had muscle fatigue in the early years of ME (if I have judged the onset correctly) but don't specifically recall much mental fatigue then. That seems to have worsened later, maybe in a progressive manner.

 

[MeSci]

@Bob ... you missed my point.

Deconditioning as a theory of why we are ill is obviously nonsense.

However we do over time loose condition... ie our muscles do become weaker.

Therefore when comparing muscle tissues, ME patients' muscle really should be compared to muscle from healthy people who are also deconditioned. That is not easy, because I cannot imagine any healthy couch potato physically doing as little as I do.

Hence the reason I was suggesting the NASA bedrest folk - the healthy volunteers asked to spend a year in bed... if I remember right.

Those folk would make excellent controls for Severe ME patients.

I don't think that my muscles have become weaker. They are only weak when I am exhausted from activity or have PEM. They also functioned poorly when I was carrying a lot of fat, but once I got rid of that they became strong again, to the extent that a man collecting some 13kg heating gas bottles I was giving away thought that I was carrying an empty one when it was in fact substantially full. It was amusing and gratifying to see him suddenly buckle under its weight when he picked it up, and the look of surprise on his face!

I think there has been at least one study on muscle strength and/or structure in ME, which found it/them to be normal.

 

[Bob]

Perhaps our muscle strength varies quite a lot from individual to individual. It might depend on many factors including severity of illness (i.e. semi-active/house-bound/bed-bound), length of illness, stage of illness, diet, ability to digest food and absorb nutrients, age, comorbid conditions (e.g. fibro, thyroid) etc etc.

Edit: Other factors might include: POTS and HPA axis dysfunction.

 

[Keela Too]

.........
I think there has been at least one study on muscle strength and/or structure in ME, which found it/them to be normal.

Hmmmm..... I'd be very surprised if my muscles remained undiminished by my 3 years of inactivity.

Even were I to be miraculously cured tomorrow, I still think it would take at least a year to build my muscle strength and capacity back to pre-illness levels. I have certainly lost a lot of muscle mass, and that alone would take time to rebuild.

A horse kept in a stable without exercise looses muscle compared to one running in a hilly field. In my view we are like the stabled horses... unable to exercise properly.

 

[alex3619]

I am not sure lack of muscle strength is a common finding. The actual finding by Ramsay was excessive muscle fatigueability, which is not the same thing. I do think some of us get sudden muscle weakness, but that is probably due to neurological issues. I also think some of us get muscle weakness from excessive activity, not just PEM but maybe something that could be called post-PEM, in which overused muscles recover even more slowly than the rest of the body.

Having said that I used to be the guy with the party trick that I could open any bottle or jar with my hands in under a second (hint, its about applied physics). Now I cannot even properly grip the jar or bottle.

PS I do think we get some muscle deconditioning from prolonged under-use, but this is not excessive compared to other sedentary groups. When its worse, I think there is a reason, and deconditioning does not explain it.

 

[MeSci]

I am not sure lack of muscle strength is a common finding. The actual finding by Ramsay was excessive muscle fatigueability, which is not the same thing. I do think some of us get sudden muscle weakness, but that is probably due to neurological issues. I also think some of us get muscle weakness from excessive activity, not just PEM but maybe something that could be called post-PEM, in which overused muscles recover even more slowly than the rest of the body.

Having said that I used to be the guy with the party trick that I could open any bottle or jar with my hands in under a second (hint, its about applied physics). Now I cannot even properly grip the jar or bottle.

PS I do think we get some muscle deconditioning from prolonged under-use, but this is not excessive compared to other sedentary groups. When its worse, I think there is a reason, and deconditioning does not explain it.

I don't know about the rest of you, but my muscles, even/especially when I have been relatively unwell, seem to exercise themselves through involuntary contraction, e.g. fasciculations (twitches), occasional cramps, myoclonus, restless legs, etc.

I don't know whether it is due to cholinergic dysfunction. I suspected early in my then-undiagnosed illness that I had organophosphate poisoning, which involves inhibition of acetylcholinesterase, which increases levels of acetylcholine and thus increased/excessive muscle contraction.

I guess we could be looking at subgroups again, and/or differences due to severity levels?

 

[lansbergen]

I don't know about the rest of you, but my muscles, even/especially when I have been relatively unwell, seem to exercise themselves through involuntary contraction, e.g. fasciculations (twitches), occasional cramps, myoclonus, restless legs, etc.

I don't know whether it is due to cholinergic dysfunction. I suspected early in my then-undiagnosed illness that I had organophosphate poisoning, which involves inhibition of acetylcholinesterase, which increases levels of acetylcholine and thus increased/excessive muscle contraction.

I guess we could be looking at subgroups again, and/or differences due to severity levels?

It sure is related to severity. When I was at my worst I had it all over my body and very frequent. Now I have not had the twitches for a while. The cramps very much decreased in frequency and are only local.

I still wonder how it is possible all this movements happen and at the same time the muscles/bones feel dull/dead.

 

[lansbergen]

I do think some of us get sudden muscle weakness, but that is probably due to neurological issues.

I think so too.

 

[Bob]

Is anyone able to explain how lactate could possibly be a fuel for energy metabolism in the brain, if it's usually considered a waste product of energy metabolism? What am I missing?

Brain metabolism
Although glucose is usually assumed to be the main energy source for living tissues, there are some indications that it is lactate, and not glucose, that is preferentially metabolized by neuronsin the brain of several mammalian species (the notable ones being mice, rats, andhumans).[13][14] According to the lactate-shuttle hypothesis, glial cells are responsible for transforming glucose into lactate, and for providing lactate to the neurons.[15][16] Because of this local metabolic activity of glial cells, the extracellular fluid immediately surrounding neurons strongly differs in composition from the blood or cerebro-spinal fluid, being much richer with lactate, as was found in microdialysis studies.[13]

The role of lactate for brain metabolism seems to be even more important at early stages of development (prenatal and early postnatal), with lactate at these stages having higher concentrations in body liquids, and being utilized by the brain preferentially over glucose.[13] It was also hypothesized that lactate may exert a strong action over GABAergic networks in thedeveloping brain, making them more inhibitory than it was previously assumed,[17] acting either through better support of metabolites,[13] or alterations in base intracellular pH levels,[18][19] or both.[20]

A more recent paper by Zilberter's group looked directly at the energy metabolism features in brain slices of mice and showed that beta-hydroxybutyrate, lactate, and pyruvate acted as oxidative energy substrates, causing an increase in the NAD(P)H oxidation phase, that glucose was insufficient as an energy carrier during intense synaptic activity and, finally, that lactate can be an efficient energy substrate capable of sustaining and enhancing brain aerobic energy metabolism in vitro.[21] The paper was positively commented by Kasischke: "The study by Ivanov et al. (2011) also provides novel data on biphasic NAD(P)H fluorescence transients, an important physiological response to neural activation that has been reproduced in many studies and that is believed to originate predominately from activity-induced concentration changes to the cellular NADH pools."[22]

https://en.m.wikipedia.org/wiki/Lactic_acid#Exercise_and_lactate

 

[Marky90]

I think this is an important study in the puzzle.

But what i dont understand is, if the muscle cells genetically change to be "worse" than normal, why do the responders to Rituximab function at previous level again? Thoughts @Jonathan Edwards? I saw your remarks about telomere, but i didnt quite get my head around it..

 

[Gijs]

I think this is an important study in the puzzle.

But what i dont understand is, if the muscle cells genetically change to be "worse" than normal, why do the responders to Rituximab function at previous level again? Thoughts @Jonathan Edwards? I saw your remarks about telomere, but i didnt quite get my head around it..

There are different subgroups that makes thinking about the puzzle so difficult. Some have autoimmunity others do have mitochondrial problems. We have different diseases even here on this forum. I really can't fit the puzzle with the findings of Julia Newton and rituximab, it doesn't make any sense to me.

 

[Marky90]

There are different subgroups that makes thinking about the puzzle so difficult. Some have autoimmunity others do have mitochondrial problems. We have different diseases even here on this forum. I really can't fit the puzzle with the findings of Julia Newton and rituximab, it doesn't make any sense to me.

A researcher on the norwegian CFS facebook group proposed that the muscle cells have adapted to autoimmunity, she thought the cellular changes probably arent short term, but the kind that lasts a while. So some sort of epigenetic adaptation. This is at least a view that could fit for those where their CFS is of autoimmune origin. I like it, was my first thought as well..