PENE, nitric oxide and nitrosative stress

[Frunobulax]

I try to wrap my tired brain around the nitrosative stress theory but I can't make pieces fit. Any help connecting the dots is appreciated. Why do we produce more nitric oxide than healthy people?

A word of warning. I'm digging into biochemistry, but I still feel like it's a foreign language to me where I may make fundamental mistakes and misunderstand key issues. So this is me talking about something I don't understand, and hoping that you point out my mistakes

Background. I think "what causes PENE" is THE question for us. I'm convinced that we have various pathomechanisms for ME so there is (very likely) not a single cause and therefore not a unified treatment, but as long as we don't understand PENE we don't know where to look.
(I know about the virus theory, but 90% of the population have EBV and herpes, so I consider it more likely that our immune system is shot for some reason and can't keep viruses in check. That is, the virus might trigger the onset of ME, but the immunodeficiency was there first. I also know about CCI, but one thing about inflammation is that it damages connective tissue. So we might have a causative chain
immunodeficiency => chronic inflammation => damage to craniocervical junction => compression of the brain stem and/or deficiencies in micronutrients => onset or worsening of ME symptoms.)

But I can't seem to find anything where the ME experts agree on regarding PENE. I find studies like https://www.mdpi.com/2075-4418/9/3/70/htm not very convincing because a lot of them indicate that we have a problem with glucose metabolism (which might or might not be a problem with pyruvate carboxylase, resulting in abnormal quotients of lactate and pyruvate), but PENE happens also for patients on ketogenic diets who don't burn glucose. So PENE doesn't seem to be related to glucose metabolism, and whatever abnormalities we see there could be a completely different issue.

Then there is Myhill, Booth and McLaren-Howard. A problem with oxidative phosphorylation (ADP recycling) would explain PENE, but it is not clear if this process kicks in for most of us.

And there is the nitrosative stress theory https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3964747/. I think the basic theory is that we have increased production of nitric oxide for some unknown reason, which reacts to the toxic peroxinitrite which inhibits the citrate cycle further and permanently damages mitochondria. According to this theory we have a vicious cycle of
higher nitrosative stress => higher production of peroxinitrite => less capacity of ATP production => more nitric oxide => even higher nitrosative stress
plus long-term reduced mitochondrial capacity independent from nitrosative stress as damage from peroxinitrite. Personally, I'm not sure if nitrosative stress isn't simply another symptom (and not the cause) as my nitrosative stress, once very much elevated, has been in normal range for a year or so -- with no change in PENE severity.

So here is where I'm stuck.

• Has anyone tried to connect both theories?
  
  
• Has anyone tried to link either theory to dietary interventions? Do ATP recycling and/or nitrosative stress change if people switch from high-carb to ketogenic diets (either protein rich like carnivore or a mostly plant-based ketogenic diet)?
  
  
• Could the ATP recycling issue actually be a consequence of a pyruvate carboxylase issue? If we convert pyruvate to lactate we should have some excess conversion from NADH to NAD+, and lack of NADH would inhibit complex I of the citrate cycle. If this is true, the Myhill, Booth and McLaren-Howard couldn't explain PENE because this effect shouldn't happen on a ketogenic diet.
  
  
• Is Omega-6 intake (which is linked to chronic inflammation) in any case connected to either theory?
  
  
• Some new findings suggest that a lack of nitric oxide might be connected to arteriosclerosis and metabolic syndrome. Uric acid is known to inhibit nitric oxide (https://www.ncbi.nlm.nih.gov/pubmed/18696365) and glucose converts to fructose in hyperinsulinemic patients which is metabolized to uric acid. Therefore we have a link from hyperinsulinemia (metabolic syndrome) to high uric acid and inhibited nitric oxide production (I think Robert Lustig explains the connection in this video
  ), and Gary Fettke connects this to inflammation
  . Bottom line: Metabolic syndrome and high carb diet leads to low nitric oxide which causes hypertension, cardiovascular disease and reduced activity of the immune system (white blood cells) and other issues.
  
  Now, this makes me wonder. Plenty of ME/CFS patients have metabolic syndrome, high blood pressure and eat a high carb diet, possibly fuelled by the aforementioned problems in the glucose metabolism (we compensate by eating more carbs, forcing higher insulin levels which fasttracks us into metabolic syndrome). Potassium helps to downregulate uric acid, and plenty of us take potassium.
  Why in the world do we have increased NO production when it should be inhibited?

 

[Wishful]

Since there are no proven theories, I find it easier to just avoid worrying too much about possible theories. It's not likely to lead to an effective treatment, at least for us non-experts. All (okay, both of) my effective treatments were not based on any theory, and I still don't have a theory for why they work for me.

I think the basic theory is that we have increased production of nitric oxide for some unknown reason, which reacts to the toxic peroxinitrite which inhibits the citrate cycle further and permanently damages mitochondria.

I don't notice any effect from taking arginine, which should boost NO production. Furthermore, peroxynitrite scavengers make my ME symptoms very much worse, so I believe that if anything my ONOO- levels are too low. I couldn't find any safe, convenient ways to boost ONOO- levels, for experimenting.

I felt worse on a ketogenic diet (maybe wasn't full ketogenic). I do better on a fairly high-carb diet (whole grains).

From: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2953417/

The role of the cofactor tetrahydrobiopterin (BH4) in NO production and its relation with arginine availability is indicated as an important explanation for the arginine paradox. This offers potential for NO regulation by dietary factors like arginine or its precursors and vitamin C. Because diets with a high saturated fat content induce high plasma fatty acid levels, endothelial NO production is often impaired due to a reduction in NOS3 phosphorylation. Increasing the arginine availability by arginine therapy or arginase inhibition was therefore proposed as a potential therapy to treat hypertension. Recent studies in septic patients and transgenic mice models found that inadequate de novo arginine production from citrulline reduces NO production. Citrulline supplementation may therefore be a novel therapeutic approach in conditions of arginine deficiency.

 

[Hip]

PENE happens also for patients on ketogenic diets who don't burn glucose. So PENE doesn't seem to be related to glucose metabolism, and whatever abnormalities we see there could be a completely different issue.

Interesting point. Though I think you still get some degree of glucose in a ketogenic diet, as glucose is made by gluconeogenesis, which creates glucose without the need for carbohydrate intake.

Why in the world do we have increased NO production when it should be inhibited?

One major source of nitric oxide (NO) is the immune system, which creates NO via its enzyme iNOS in order to fight pathogens, since NO has antimicrobial effects. The two other sources of NO are the NO used as a signaling molecule for vasodilation (generated by the enzyme eNOS), and the NO used as a neurotransmitter signaling molecule in the brain (generated by nNOS).

The amount of NO created when the immune system fights infections is much higher than the NO created for vasodilation or as a neurotransmitter. So you might expect NO to be high when there are chronic infections in the body.

 

[Frunobulax]

Since there are no proven theories, I find it easier to just avoid worrying too much about possible theories. It's not likely to lead to an effective treatment, at least for us non-experts.

I disagree
After my ME diagnosis I started research into all symptoms I had, and managed to tweak my diet and supplements to get rid of heartburn (and eliminated PPI drugs), psoriasis, gout (+drugs), hypertension and obesity, plus my restless legs got a lot better. It only took a year, while numerous doctors only managed to make things worse in more than a decade. Most of what I did was pretty much the opposite of common recommendations, but was based on pathomechanisms. Example: I tried to get rid of the PPIs I took for my heartburn for many years, as they have really nasty side effects especially for ME/CFS patients. Everything failed, including fundoplication surgery. As it turned out all theories from my doctors were wrong (hiatus hernia and whatnot), heartburn in my case was caused by a combination of lectins, metabolic syndrome and potentially reduced nitric oxide - the solution was a low carb diet, getting rid of most lectins and a somewhat convoluted path to taper PPIs (which have a nasty rebound effect). It took some research to figure it out, but it's now crystal clear to me on a biochemical level, and it was certainly worth the effort.

Medical research today is mostly available to the public, only few studies are behind a pay wall. And there is so much bs out there that I don't believe a single thing without having a good look at the studies itself. Actually the vast majority of studies in nutrition needs to be chucked, for various reasons. (Nutrition is especially bad. Richard Feinmans book "Nutrition in crisis" is an excellent read if you want to know more about that.) That's the reason why we can literally vast numbers of studies with opposing claims, is there any good reason to have 60 studies as to whether sugar drinks cause obesity, with 25 studies saying "nay" and 35 saying "aye"? There is nothing scientific about that. But unfortunately most of our medical knowledge is built on such shaky ground.

I don't notice any effect from taking arginine, which should boost NO production. Furthermore, peroxynitrite scavengers make my ME symptoms very much worse, so I believe that if anything my ONOO- levels are too low. I couldn't find any safe, convenient ways to boost ONOO- levels, for experimenting.

ROS and RNS have a u-shaped optimal curve, so too much is just as bad as not enough. I wouldn't be surprised if we were on somehow distributed on both sides of the optimum, with some (maybe more) having too much ROS/RNS and others having not enough.

However, our nitrosative stress could also come from the fact that (for whatever reason) more NO reacts to nitric peroxide and less NO is where it's supposed to be, so we could have high nitrosative stress and low NO levels. But that's only a theoretical approach. (You should always consider the inverse theories. Sometimes biochemistry is complicated.)

Are your homocysteine and uric acid low? Both can inhibit NO generation. What's your blood pressure?

I felt worse on a ketogenic diet (maybe wasn't full ketogenic). I do better on a fairly high-carb diet (whole grains).

Did you give it enough time? Depending on your insulin levels (HOMA-IR and the like) it takes 3-4 weeks for the metabolic change to ketones, and the "keto flu" might actually be worse if you are not strictly keto. If you digest some carbs you'll still have fairly high insulin levels, which block ketone generation from your body fat. Thus, there is not enough energy from carbs (as you eat low carb) but you can't use energy from your fat cells (as insulin is too high).

There are some people who can't go on keto due to fat metabolism issues or allergies, but for most of us keto should be much better as it avoids the pyruvate carboxylase problems mentioned above.

From: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2953417/

I'll check out that article. I'm a bit wary as they didn't mention uric acid which is crucial, and there seem to be errors regarding dietary factors (the usual bs mixing up carbs and fat, because today we know that a high-carb diet causes hypertension and arteriosclerosis and cholesterol has nothing to do with that), and frankly there is no biochemical model to explain whatever they want to say. But then I only scanned it briefly.

 

[Frunobulax]

Interesting point. Though I think you still get some degree of glucose in a ketogenic diet, as glucose is made by gluconeogenesis, which creates glucose without the need for carbohydrate intake.

Our muscles run exclusively on ketones after a few weeks. We need some glucose for red blood cells (that have no mitochondria) and just a little bit for sperm (which needs fructose that is generated from glucose). Some people claim that the brain needs glucose, but AFAIK there isn't a single study to back that up. In any case the rate of the conversion is really low, people can water fast forever (where some muscle protein is converted to glucose) and still not lose a lot of lean muscle mass.

One major source of nitric oxide (NO) is the immune system, which creates NO via its enzyme iNOS in order to fight pathogens, since NO has antimicrobial effects. The two other sources of NO are the NO used as a signaling molecule for vasodilation (generated by the enzyme eNOS), and the NO used as a neurotransmitter signaling molecule in the brain (generated by nNOS).

The amount of NO created when the immune system fights infections is much higher than the NO created for vasodilation or as a neurotransmitter. So you might expect NO to be high when there are chronic infections in the body.

Very interesting, thanks. So where does the NO come from, and how is NO production triggered? The body simply manufactures NO, which convert to RNS automatically causing nitrosative stress? I somehow assumed that ROS/RNS production is the result of a more targeted reaction.

My favorite ME theory is still brain inflammation (Jarred Youngers research), which could be triggered by toxins but also by stuff like arachidonic acid. AFAIK arachidonic acid activates the immune system which could create RNS/ROS. So basically, it might be possible that (at least for some of us) there is no infection but only an autoimmune condition where the immune system is activated through arachidonic acid, which comes from omega-6 intake in our diet? (See Gary Fettkes talk that I linked.) If that is true, it would be helpful to reduce nitrosative stress (for example via agressive B12 supplementation). OTOH, if we're fighting real invaders (EBV theory or bacteria) it might actually be better to increase RNS production?

 

[Hip]

Our muscles run exclusively on ketones after a few weeks. We need some glucose for red blood cells (that have no mitochondria) and just a little bit for sperm (which needs fructose that is generated from glucose). Some people claim that the brain needs glucose, but AFAIK there isn't a single study to back that up.

Fair enough.

So where does the NO come from, and how is NO production triggered?

NO has an extremely short half life in the blood of around 1 second, so it has to be constantly produced when needed.

It's these three NOS enzymes I mentioned which create NO: the enzymes act on arginine, and from that they create NO. That's why arginine supplementation can increase NO levels.

 

[Frunobulax]

One major source of nitric oxide (NO) is the immune system, [...]

The amount of NO created when the immune system fights infections is much higher than the NO created for vasodilation or as a neurotransmitter.

After sleeping on this... This would rule out nitrosative stress as PENE mechanism, wouldn't it? The theory that peroxinitrite is responsible for PENE would require a mechanism to generate NO primarily under physical activity.

 

[percyval577]

The amount of NO created when the immune system fights infections is much higher than the NO created for vasodilation or as a neurotransmitter. So you might expect NO to be high when there are chronic infections in the body.

After sleeping on this... This would rule out nitrosative stress as PENE mechanism, wouldn't it? The theory that peroxinitrite is responsible for PENE would require a mechanism to generate NO primarily under physical activity.

It´s not necessarily ruled out, the immunesystem might produce small amounts of triggered NO regularily, and this might be subject to an adjustment, which could get high driven, say after certain infections or chemicals.

I for long thought that this is the main mechanism in (my) mecfs. I tried a short theory here (including the two surrounding posts). This article gives a summarizing on the iNOS in this respect.

I held to the theory also as it explained all observations of influences I discovered, a strong sensitivity to manganese, the - not lasting - success of iNOS inhibitors, and the fact that I could get worse from ham (compared to non-ham) - containing some LPS -, and some fungi in a fish from the supermarket. I felt good for half a day after having removed a candida albicans. Especially, I improved very slowly from a low manganese diet (pain), though while being worse in thinking and seeing (non-progredient), which I blame/d partly the try to make new synapses, like in a small child. Confusion got somehow worse over the time, but sleep was immediatly fine.

Currently I don´t know how important a factor the iNOS may be. I think the symptoms are generated in the basal ganglia and the thalamus, causing downstream effects as well being open for effects, of course. I think the geometry of synpatical patterns has changed, but each cell works still in a mode that would also occur in health.

 

[Hip]

After sleeping on this... This would rule out nitrosative stress as PENE mechanism, wouldn't it? The theory that peroxinitrite is responsible for PENE would require a mechanism to generate NO primarily under physical activity.

Well ME/CFS patients' muscles are found to have enterovirus infections, and we know from coxsackievirus B myocarditis patients that exercise makes enterovirus infection worse, so perhaps exercise will worsen the muscle in infections in ME/CFS, leading to an increase immune response, which may involve more NO. But that's very speculative.

 

[Cherry]

What does PENE stand for?

 

[Hip]

What does PENE stand for?

PENE is just a different name for PEM (post-exertional malaise). The term PENE is used in the International Consensus Criteria for ME/CFS.

PENE stands for post-exertional neuroimmune exhaustion. However, I dont think it is a good name, because it assumes that PEM is caused by neuroimmune effects, but in fact we still have no idea of what causes PEM, so it is jumping the gun a bit to call ME/CFS patients' post-exertional symptoms PENE.

 

[Cherry]

Thanks

 

[Wishful]

Are your homocysteine and uric acid low? Both can inhibit NO generation. What's your blood pressure?

If those factors were measured in general testing, nothing unusual came up. My blood pressure was normal. I'm not surprised that it's taken so long for ME to be recognized, given the lack of clearly measurable abnormalities in normal medical testing.

 

[Frunobulax]

If those factors were measured in general testing, nothing unusual came up. My blood pressure was normal. I'm not surprised that it's taken so long for ME to be recognized, given the lack of clearly measurable abnormalities in normal medical testing.

Not sure as there are significant differences depending on which country you're in.
Here in Germany homocysteine is not covered by insurance and therefore not routinely measured, a test is something like $40. Uric acid is a standard parameter, but IMO the normal range goes up way too high. Very many patients have high uric acid (as fructose is metabolized to uric acid) so maybe half the population has values that are higher than they should be. And as we redefine "normal range" as "as observed in the population" and not "as it should be", that may be a problem. Metabolic syndrome causes high blood pressure (say over 130:85), possibly via high uric acid. So people with high blood pressure should always check if they have high insulin resistance (metabolic syndrome) - low carb diet may resolve a lot of things including high uric acid.

The thing is that we don't know the role of uric acid. We discovered the importance of nitric oxide just 20 years ago (or so) -- uric acid in low doses is important (antioxidant and whatnot), in high doses it's really bad (gout), but we haven't really figured out it's place in the puzzle that is inflammation and ME/CFS.

There is a snag: High oxalate consumption may lead to high uric acid too. Many people who go on a low carb diet to fix metabolic syndrome may actually observe rising uric acid because they suddenly eat a lot of high-oxalate food (almonds, spinach, other green vegetables). That's where I'm at right now, I got a lot of relief from lowering my insulin but my uric acid is still high, and I'm going low-oxalate for a few months to see if it makes a difference.

 

[Frunobulax]

PENE stands for post-exertional neuroimmune exhaustion. However, I dont think it is a good name, because it assumes that PEM is caused by neuroimmune effects, but in fact we still have no idea of what causes PEM, so it is jumping the gun a bit to call ME/CFS patients' post-exertional symptoms PENE.

Naming in a ME context is difficult. I distinctly prefer ME over CFS -- most people over here don't make a difference (which is a discussion I don't want to go into right now) and use CFS, but people not familiar with the disease usually react "fatigue? Yeah, I'm often fatigued after a hard days work". ME sounds much more serious and mysterious

It's similar with PEM/PENE. I prefer PENE to make a point that we have neurological symptoms after exertion.

 

[olegsel]

Are your homocysteine and uric acid low? Both can inhibit NO generation.

???

 

[Cherry]

Forgive me for not fully understanding the whole thread, but I wanted to ask a question about NO (nitric oxide). Like most ME/CFS sufferers I have orthostatic intolerance. Mine is the Neurally Mediated Hypotension variety, meaning my blood pressure drops if I've been standing still (waiting in line?) for more than 5 minutes, and my heart rate does not increase to compensate. (This is especially a problem for me after a long period of bed rest.)

I'm wondering if orthostatic intolerance is a consequence of excess NO causing the blood vessels to relax when they should be contracting. To maintain adequate blood supply to the brain, a higher blood pressure must be sustained during standing then was typical for a person when they are sitting or lying down. Am I correct in assuming the increase in blood pressure is achieved by the contraction of blood vessels? I have seen suggestions to tighten abdominal muscles to reduce blood pooling in the abdomen, and using leg muscles by, for example, swaying back and forth to encourage blood flow when stuck standing in line.

Another question. Dr. Systrom has observed that people with ME/CFS tend to have cardiac preload failure during an exercise challenge. Is it likely that this is the result of the same poor vascular tone that may be causing orthostatic intolerance?

 

[Cherry]

Is Omega-6 intake (which is linked to chronic inflammation) in any case connected to either theory?

I have read that the theory that high Omega 6 intake, or high Omega 6 to Omega 3 ratio leading to more inflammation, is being disputed, and new studies fail to support it. https://www.health.harvard.edu/newsletter_article/no-need-to-avoid-healthy-omega-6-fats
However, there are current journal articles that still support the theory, so we may have to wait for the final verdict.

 

[Cherry]

Some new findings suggest that a lack of nitric oxide might be connected to arteriosclerosis and metabolic syndrome. Uric acid is known to inhibit nitric oxide (https://www.ncbi.nlm.nih.gov/pubmed/18696365) and glucose converts to fructose in hyperinsulinemic patients which is metabolized to uric acid. Therefore we have a link from hyperinsulinemia (metabolic syndrome) to high uric acid and inhibited nitric oxide production

i thought I had read somewhere that the typical ME/CFS sufferer does not have metabolic syndrome. I know for myself, my blood pressure, blood sugar and cholesterol are all normal.
You mention that metabolic syndrome suppresses NO, and that ME/CFS patients tend to have high NO (or nitrosative stress), so is there any connection between these things?

 

[Frunobulax]

i thought I had read somewhere that the typical ME/CFS sufferer does not have metabolic syndrome.

If you find that quote then please share it Two thirds of the population have MetS, why should ME/CFS patients be different? Severe cases of metabolic syndrome usually show signs of mitochondrial disorder. There are many reports about patients doing better on ketogenic diet, and
http://simmaronresearch.com/2019/08/me-cfs-seahorse-energy-production-study-shows-surprises/ reports on glycolysis issues that presumably could be resolved using a ketogenic diet.

And there is another possible connection. MetS drives inflammation, and ME/CFS is an inflammation driven disease https://forums.phoenixrising.me/threads/causes-for-me-cci-vs-inflammation.78586/. So clearly MetS could be one (of many) factors in this disease.

The reason for that claim may be that there is no formal definition of MetS, and many people use bad glucose control as criteria. The damage (especially the inflammation) is driven by high insulin, and there are many people with very high insulin levels but still decent glucose control. These people pass the usual diabetics tests (Kraft patterns II and IIIa) but may show other symptoms.

You mention that metabolic syndrome suppresses NO, and that ME/CFS patients tend to have high NO (or nitrosative stress), so is there any connection between these things?

I wish I knew

I'm wondering if orthostatic intolerance is a consequence of excess NO causing the blood vessels to relax when they should be contracting. To maintain adequate blood supply to the brain, a higher blood pressure must be sustained during standing then was typical for a person when they are sitting or lying down. Am I correct in assuming the increase in blood pressure is achieved by the contraction of blood vessels?

I'm no cardiologist. Heck, I'm no doctor. But there is a heated scientific debate about this. Most people claim that external factors will drive blood pressure (like salt), however there is some good evidence contradicting this (one of them that lowering salt intake will change blood pressure only to a very small degree, and it does not change mortality at all). The opposing view is that the body regulates blood pressure itself, for example if arteries are too rigid (possibly because there is not enough NO), then blood pressure goes up. That's why MetS causes high blood pressure (and we know this connection for sure, because the overwhelming majority of patients will see a marked improvement in their BP if they go on a ketogenic diet within 2 weeks). So a lack of NO would actually drive up blood pressure.

I suspect that orthostatic intolerance is simply a lack of energy. Perhaps we DO have low NO levels, the usual regulating mechanisms would drive up BP and we don't have the extra energy to do that.

But this is pure speculation. I wish I had a more definitive answer.

I really, really, really would like to see a study how ME/CFS patient metabolism changes with ketogenic diet. This would answer a LOT of these questions. It might also prevent us from researching a dead end, that is glucose metabolism. It is very possible that the effects that Maureen Hanson and others are researching are just signs of severe metabolic syndrome, however MetS is clearly not the root cause for ME/CFS (though I believe it to contribute to the severity of the disease).

Another question. Dr. Systrom has observed that people with ME/CFS tend to have cardiac preload failure during an exercise challenge. Is it likely that this is the result of the same poor vascular tone that may be causing orthostatic intolerance?

No idea. Interesting question. I'll think about this.

I have read that the theory that high Omega 6 intake, or high Omega 6 to Omega 3 ratio leading to more inflammation, is being disputed, and new studies fail to support it. https://www.health.harvard.edu/newsletter_article/no-need-to-avoid-healthy-omega-6-fats

Well, I'll try to find the study and have a look at it. (The article really could have linked it directly.) However, there were many AHA publications in the past of a very questionable nature, dismissing evidence from new studies without giving any proof to the contrary and citing papers from the 60s in support of their views. I strongly suggest to read this commentary from Gary Taubes on one of their recent statements.

One trick that they routinely use is to cite studies that show that omega-6 lowers rates of heart disease. This is 100% true, however the very same studies show that total mortality goes up if you replace saturated fat (butter) with omega-6. So you will actually die earlier if you do that, but you will die of cancer, artherosclerosis or any of the other reasons -- but not of heart disease. Great achievement, isn't it? Many of these studies are sponsored by the food industrie making tons of profit from vegetable oils.