Ammonia and BH4 - is this a myth or something?

[Kimsie]

I have always assumed that Amy Yasko's statements about how getting rid of ammonia takes BH4, and I have even quoted her on this. But now I have been looking, and I can't find any evidence at all the BH4 is used to get rid of ammonia.

Does anyone have any info on this?
Thanks,
Kim

 

[Kimsie]

I think I have found my own answer on this. I saw the other thread that was last posted on earlier this year on this subject.

My conclusion is that BH4 is not used to detoxify ammonia, and it is not used in the urea cycle. It happens that BH4 is used to make nitric oxide, and that one product of that pathway can also be used in the urea cycle, but the urea cycle goes along just fine without BH4.

That said, ammonia is costly in terms of ATP and in the end it costs 2 ATP for each molecule of ammonia. When the electron transport chain is inhibited this is metabolically expensive.

There is a link between ammonia and low thiamine, which I don't really understand at this point. Formerly I thought it had something to do with the Pentose Phosphate pathway and NADPH, but now I need to do more research on it.

 

[Gondwanaland]

Hopefully this article can give you some insight into a missing link...
http://www.health24.com/Diet-and-nu...omplete-guide-to-thiamine-vitamin-B1-20120721

 

[nandixon]

@Kimsie
I also believe it's true that Yasko is incorrect about ammonia elimination consuming BH4, but the one caveat I think may be present is:

It would appear that the more arginine that is produced from ammonia in the Urea Cycle then the more arginine is likely to enter the Nitric Oxide (NO) Cycle. There, BH4 is used to convert the arginine to NO. And while it's true that BH4 only acts as a catalyst for this reaction and is not actually consumed (which Yasko may not have realized), if sufficient methylfolate is not present to protect the BH4 from peroxynitrite, then decoupling occurs and significant loss of BH4 could result as a vicious cycle ensues (i.e., decoupling->superoxide-> peroxynitrite->destruction of BH4-> more decoupling-> superoxide, etc.).

So with sufficient methylfolate, ammonia detoxification should not cause a loss of BH4. But if there's not enough methylfolate present to scavenge peroxynitrite then I think ammonia could, indirectly, cause some loss of BH4. That's how I'm presently looking at it, anyway.

(Note: The literature reference for BH4 not being consumed in the production of NO by nitric oxide synthase is given in this post here: http://forums.phoenixrising.me/index.php?threads/bh4-needed-for-ammonia-detox.21614/#post-411430)

 

[adreno]

Quite a few of Yasko's claims have been found to be unsupported by any evidence, so this is not surprising.

AKG should help to clear ammonia.

 

[Kimsie]

@Kimsie
I also believe it's true that Yasko is incorrect about ammonia elimination consuming BH4, but the one caveat I think may be present is:

It would appear that the more arginine that is produced from ammonia in the Urea Cycle then the more arginine is likely to enter the Nitric Oxide (NO) Cycle. There, BH4 is used to convert the arginine to NO.

The synthesis of NO is very tightly regulated, so argenine levels can only limit NO synthesis by being too low, it can't raise NO synthesis by being high.

And while it's true that BH4 only acts as a catalyst for this reaction and is not actually consumed (which Yasko may not have realized), if sufficient methylfolate is not present to protect the BH4 from peroxynitrite, then decoupling occurs and significant loss of BH4 could result as a vicious cycle ensues (i.e., decoupling->superoxide-> peroxynitrite->destruction of BH4-> more decoupling-> superoxide, etc.).

Peroxynitrite is metabolized by glutathione, as is H2O2, and so the destruction of BH4 by peroxynitrite is probably happens because of a lack of NADPH to recycle the glutathione to get rid of the peroxynitrite. (I am figuring these things out by thinking about your response, I hadn't thought about this before.)The lack of NADPH also affects the synthesis of BH4 because it is used to make BH4 in both BH4 recycling pathways, and in the pathway to synthesize BH4. .

So with sufficient methylfolate, ammonia detoxification should not cause a loss of BH4. But if there's not enough methylfolate present to scavenge peroxynitrite then I think ammonia could, indirectly, cause some loss of BH4. That's how I'm presently looking at it, anyway.

Here is an interesting article.
I am going to do more research on these lines. I want to know by what mechanism folate can scavenge peroxynitrite, because if it is because the folate cycle can be a net NADPH producer, then since CFS people are probably using the folate cycle as an ATP producer, it won't produce NADPH very well along with ATP, but if it has some other way of scavenging peroxynitrite, well, I would be interested to know what that was.

Ammonia is tied into these problems in some way. In this article they talk about how in vitro cells produce NADPH, but when glycine is added to the nutrient mix, the more glycine, the less cell growth. I think that is because when glycine is metabolized to produce either NADPH or ATP, ammonia is produced, and the cells in vitro have no way to get rid of the ammonia. I need to think about this more. There might be something helpful here.

 

[Kimsie]

Quite a few of Yasko's claims have been found to be unsupported by any evidence, so this is not surprising.

AKG should help to clear ammonia.

AKG does help clear ammonia; it should help in the peripheral parts of the body, but I am pretty sure it doesn't cross the BBB.

I have seen people confidently asserting the AKG does cross the BBB, but I can't find any studies that show that it does, and I tried it with our son who has depression quite some time ago and it should have helped his symptoms if it crosses the BBB but it didn't do a thing.

Pyruvate does cross the BBB and can help with ammonia to some degree. Thiamine can help, at least with some people, but I haven't figured out why it helps yet.

The worst thing about ammonia is that it drains ATP, whether you take extra AKG or pyruvate or not.

 

[aquariusgirl]

kimsie...thiamine might help cos it requires atp to make urea...would that fit? but regular thiamine doesn't cross the bbb very effectively. you would need sulbutiamine.

 

[Gondwanaland]

There is a (not very explicit) simplified chart here showing how thiamine is needed to generate ATP and CO2 which are needed to clear ammonia by turning it into urea.

 

[Kimsie]

Gondwanaland, I already know which enzymes in the body are known to use thiamine (there are not very many) and how thiamine is used in the TCA cycle. The thing that puzzles me is that my husband, who does not have CFS has taken many things which push the TCA cycle and none of them had any effect on the amount of ammonia in his sweat, only thiamine about 1 gram a day affected the ammonia smell of his sweat, and it didn't have any other noticeable effects. I think it is possible that the thiamine affects ammonia in some way not really connected with the TCA cycle.

Thiamine deficiency has a lot of symptoms that can't really be easily explained by the known enzymes which use thiamine. I can't help thinking that some day they will discover some other functions of thiamine.

 

[Kimsie]

I would like to post on some of my research for today. Here is a quote (followed by a translation into layman's terms) from this article I linked above.

One of the most important mechanisms for producing mitochondrial dysfunction in NO/ONOO- cycle diseases is thought to involve the nicking of deoxyribonucleic acid by peroxynitrite-derived free radicals, leading to major stimulation of polyadenosine diphosphate (ADP)-ribosylation of chromosomal proteins. The substrate for ADP ribosyltransferase activity is nicotinamide adenine dincleotide (NAD) and many inflammatory diseases can lead to major depletion of NAD/NADH pools via this mechanism, with NADH depletion leading to mitochondrial dysfunction. High concentrations of nicotinamide effectively inhibit poly ADP-ribosylation, leading to restoration of NAD/NADH pools and therefore improved mitochondrial function, also lowering other NO/ONOO- cycle elements.

Simplified translation: The nitric oxide/peroxynitrite cycle damage to mitochondria is thought to involve damage to DNA leading to a draining of niacinamide by an enzyme that uses niacinamide as a substrate. Many inflammatory diseases can have a depletion of the NAD/NADH pool this way, which causes mitochondrial dysfunction. High concentrations of niacinamide will prevent this type of inhibition of the NAD/NADH pools and improve mitochondrial function and help slow down the negative cycle.

If this is true, then it would be another reason besides ones I have given in other threads for taking niacinamide in larger doses. Taking niacinamide can certainly increase the NAD/NADH pool, especially if you take some ribose and maybe glutamine with it. That said I have to warn against increasing activity when you take these things (a person wants to increase activity because they lead to an increase in energy). I explain why in the rest periods thread.

 

[Gondwanaland]

And B3 impairs B1 absorption, they should not be taken at the same time (sorry, don't have the reference at hand now)
And low folate impairs B1 absorption

 

[nandixon]

The synthesis of NO is very tightly regulated, so argenine levels can only limit NO synthesis by being too low, it can't raise NO synthesis by being high.

I was thinking in terms of inducible NOS (NOS2), which isn't regulated like eNOS and nNOS. Increased arginine concentrations are definitely going to result in increased NO production by iNOS, subject to obvious physiological considerations.

Peroxynitrite is metabolized by glutathione, as is H2O2, and so the destruction of BH4 by peroxynitrite is probably happens because of a lack of NADPH to recycle the glutathione to get rid of the peroxynitrite. (I am figuring these things out by thinking about your response, I hadn't thought about this before.)The lack of NADPH also affects the synthesis of BH4 because it is used to make BH4 in both BH4 recycling pathways, and in the pathway to synthesize BH4.

It's true that glutathione is also a peroxynitrite scavenger, but with respect to the specific action of maintaining the integrity of BH4 during its catalytic role of one-electron transfer for NOS activity, methylfolate has the preeminent role of peroxynitrite scavenger during that process.

 

[adreno]

I find that if I increase B3, I also have to increase B2, and B1.

 

[Kimsie]

And B3 impairs B1 absorption, they should not be taken at the same time (sorry, don't have the reference at hand now)

I have never heard this before. If you get the chance, I would like to see the reference.

 

[Gondwanaland]

I have never heard this before. If you get the change, I would like to see the reference.

It actually is the other way around, B1 inhibits B3. Sorry, no scientific study to reference here.

B1 inhibits B3 absorption
Biotin inhibits B5 absorption

I think B1 can be taken with B2, and I certainly don't see any contraindication for taking B9 with B12.

I will let others chime in on this subject, but like others, I found that B2 has obvious absorption/competition issues when combined in a complex.

And here is a very interesting post by @Violeta about a B1 cascade effects.

 

[Kimsie]

I find that if I increase B3, I also have to increase B2, and B1.

It's a good idea to take extra of all the B's when you take a lot of any one of them. How much extra of B1 and B2 is somewhat individual from what I can see.

 

[Kimsie]

I was thinking in terms of inducible NOS (NOS2), which isn't regulated like eNOS and nNOS. Increased arginine concentrations are definitely going to result in increased NO production by iNOS, subject to obvious physiological considerations.

I have to study this some more. I started looking into it, but it will take some time for me to get a handle on it.

I think the most important thing about the subject is that we need to do what we can to avoid producing a lot of ammonia, even if BH4 isn't affected by it, because is is costly in terms of ATP. I am thinking of what might be the best way to do this. Limiting protein, especially meat protein to a certain extent would be helpful, but I think you would want to take methionine and some NAC to make sure that you are not short in methylation or glutathione synthesis. Limiting meat protein is difficult for people who have trouble with glucose metabolism, though, so that might not work for everyone.

It's true that glutathione is also a peroxynitrite scavenger, but with respect to the specific action of maintaining the integrity of BH4 during its catalytic role of one-electron transfer for NOS activity, methylfolate has the preeminent role of peroxynitrite scavenger during that process.

So far I can't find anything to convince me that the role of folate in scavenging peroxynitrite is not related to it's role in NADPH synthesis, either by producing BH4 or by recycling glutathione. Don't get me wrong - I would be delighted if folate could reduce superoxide or scavenge peroxynitrite in another way because I am looking for supplements that could do that very thing without using NADPH.

Keep in mind that when a study says that 5-MTHF did something in a study, what they mean is that 5-MTHF was the form of folate they used in the study, it doesn't necessarily mean that 5-MTFH was the form that accomplished whatever the study said that the folate did. The form of folate molecules changes rapidly all the time in the cell. So far I haven't seen anything that shows that they proved that 5-MTHF was the form that did the job. So it could easily be another reaction, such as the MTHD or the dihydrofolate reductase that helped lower peroxynitrite.

One reason I think it is so important to know how folate reduces peroxynitrite is because if a person has an inhibited electron transport chain and is using the folate cycle for ATP recycling, then adding more folate can limit the availability of B6 if the SHMT enzyme is working well in that person. This is what happens to my son, D (for depression). He has been working on rest periods for over a week, and he hasn't felt depressed since I lowered his folate to 1 mg per day. Today I decided to try giving more folate, because I thought that if he was using the rest periods it might not drain his B6 enough to cause depression and maybe it would have a net effect of lowering ROS. Well, he got depressed again, but not too badly, since it was only 1.6 mg extra.

Even if a person does not get obvious symptoms from the lack of B6 availability, it will affect their ability to make heme, which is required in the electron transport chain and for the synthesis of catalase, and so a lack of available B6 will increase oxidative stress.

I suspect that the studies showing a peroxynitrite scavenging effect of folate might only apply when there is not a shortage of ATP, and the folate cycle is not being used as a backup ATP source. Also, if the ETC is not inhibited, and ATP synthesis is not a problem, then the ammonia produced by the glycine decarboxylase, which is inevitable when the folate cycle is going top speed, is not going to be a problem.

I know that you have seen my folate cycle illustration but I put it here for those reading this thread who have not seen it to show what I am talking about.

In someone who is low on ATP and NADPH these pathways will be pulled more towards the directions I have in the red arrows.

Anyway, my point is that I think it is very important to be sure that folate will really work as a net antioxident in people with mitochondrial failure, because taking a lot of folate (maybe more than 2 mg a day, maybe a little less) might increase problems in other areas for those individuals. I haven't seen tests on this that were done with people with mitochondrial dysfunction, have you?

If you have the time maybe you can give me the most convincing reference that you have to support the idea that folate has a role as a peroxynitrite scavenger that does not rely on its ability to generate NADPH and/or BH4. I have spent quite a bit of time looking and I haven't found a good one, yet.

 

[nandixon]

This article here:

5-Methyltetrahydrofolate Rapidly Improves Endothelial Function and Decreases Superoxide Production in Human Vessels: Effects on Vascular Tetrahydrobiopterin Availability and Endothelial Nitric Oxide Synthase Coupling
http://circ.ahajournals.org/content/114/11/1193.long

which builds upon (or explains) the earlier work of two other research groups (neither of which were aware of the peroxynitrite scavenging ability of methylfolate as related to BH4):

Interaction of 5-methyltetrahydrofolate and tetrahydrobiopterin on endothelial function
http://ajpheart.physiology.org/content/282/6/H2167.full

and

Folic Acid Reverts Dysfunction of Endothelial Nitric Oxide Synthase
http://circres.ahajournals.org/content/86/11/1129.full

(Also, this easy to read article here gives a good overview of the whole BH4/NOS/decoupling issue:
Recoupling the Cardiac Nitric Oxide Synthases: Tetrahydrobiopterin Synthesis and Recycling
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3406312/)

 

[adreno]

It's a good idea to take extra of all the B's when you take a lot of any one of them. How much extra of B1 and B2 is somewhat individual from what I can see.

Would you say that it's a good idea to increase even folate when increasing B3? I am wondering which ratio between B3 and folate is optimal. How much folate would you need to take when taking, say 500mg B3?