Community symposium on molecular basis of ME/CFS at Stanford Discussion Thread

[bthompsonjr1993]

I'm definitely not saying that. I'm saying that, if I understand the timeline correctly: Phair/the Ron Davis team noticed that the IDO2 gene might be a potential problem from the severely ill patients study. Phair then came up with the idea that a defective IDO2 might mean that tryptophan isn't getting properly catabolized if the tryptophan levels rise high enough to significantly inhibit the IDO1 enzyme - because there's not a working IDO2 enzyme as a backup. The team then did some tracer experiments that appear to show that indeed (intracellular) tryptophan levels are inappropriately increased and kynurenine decreased just as you'd expect. Bingo! So now they're thinking that the metabolic trap idea (i.e., an inhibited IDO1 with no IDO2 as backup) might very well be correct.

The possible problem, though, is that the Michaelis-Menten chart that Phair presented appears to indicate they may be giving IDO2 a much greater affinity (~200 μM) for tryptophan than what the literature is saying (i.e., ~7000 to 9000 μM). If that's true, then there’s likely no metabolic trap, per se, because even a perfectly working IDO2 enzyme isn't likely to help enough because its ability to catabolize tryptophan is so poor at physiological levels. But like I said previously, maybe I'm misinterpreting something.

IDO2 was only discovered in 2007, and at that time, if I remember correctly, it was thought it basically had the same function as IDO1, i.e., a (redundant) enzyme that catabolizes tryptophan. It's become apparent though, that it's role is much more likely to be immunomodulatory or regulatory (including with respect to IDO1). And that's consistent with its poor enzymatic ability (although it's possible that its true substrate hasn't been determined yet).

So IDO2 might very well be important with respect to tryptophan but, from what I can tell, probably indirectly and not by directly catabolizing it.

What “literature” is there saying that IDO2 has a weaker affinity for tryptophan than what Ron and Rob are saying?

 

[nandixon]

What “literature” is there saying that IDO2 has a weaker affinity for tryptophan than what Ron and Rob are saying?

The 3 studies that I cited higher up in this same thread here. I wrote to Dr Phair a few days ago to ask about the seeming discrepancy but haven't heard back yet.

I suppose it's possible that the team may have done their own kinetic study and came up with the much smaller Km and they're comfortable with that.

There is one example, too, in a specialized type of white blood cell called a dendritic cell where the activities of IDO1 and IDO2 towards tryptophan might actually be much more similar than what the 3 formal kinetic studies have shown. So perhaps cell type and/or reaction conditions are critical for IDO2 to achieve its true enzymatic capability. However, dendritic cells only constitute a tiny fraction of white blood cells (on the order of 0.5%, I believe), which I think is what Phair is studying. They might be very important though.

Whether the metabolic trap theory is correct or not, the preliminary finding of the reduced intracellular ratio of kynurenine/tryptophan that Phair’s hypothesis led to could end up being very helpful for figuring out what's going on in ME/CFS if it holds up beyond the 6 patients.

 

[GodGenghis]

I dont know what kind of effect a kynurenine pathway trap might have on urine metabolites, but my quinolinic acid and kynurenic acid are as follows. Kynurenic is center of reference range, and quinolinic is low normal.

Pulled from an old Organic Acids Test

 

[Jenny TipsforME]

You mention that using an antibiotic brought temporary relief. Could you give a few details about the antibiotic, duration of treatment, improvement experienced and how long it lasted?

No it’s a hazy memory (probably 10 years ago). It wasn’t a dramatic remission I just generally improved.

 

[Janet Dafoe]

I am not 100% sure of all of the intricacies of all of this, but prior to ME/CFS, my tryptophan level was normal. I developed ME\CFS after being on high dose melatonin for 2 years and then 5-HTP for sleep, and my tryptophan level became high when all my other aminos were low.

I am not severe, but am mild/moderate. A
Diagnostics Solutions Cytokine Panel was fairly inexpensive and showed the high IFN-gamma... I'm a little gunshy of all of this right now, and think getting good data before going off and experimenting might be a prudent step, as if something goes wrong, you can at least know what the test conditions were before trying something else.

Keep in mind that it matters where you measure the tryptophan. Ron is measuring it in CELLS, not in plasma. The results are different.

 

[Cam Newton]

Keep in mind that it matters where you measure the tryptophan. Ron is measuring it in CELLS, not in plasma. The results are different.

How did the scientists at the conference react to the metabolic trap? Did anyone think it was possible?

I’m referring to the conference you mentioned that Ron was presenting at.

 

[Badpack]

https://www.researchgate.net/figure...lar-tryptophan-levels-and-does_fig2_269765865

So is this maybe the reason why some ppl greatly improved using Sirolimus/Rapamun ? Because it changes the tryptophan intake into cells ?

Edit, btw i tried Sirolimus for 1 month and it did nothing for me

 

[energyoverload]

Just to feed in an extra case here - peviously having tried dietary tryptophan depletion combined with high dose BCAAs to inhibit LNAA dependent transport, and having personally found this transient deprivation not to have any major detrimental effects, I decided to revisit this in light of Phair's hypotheisis, but with an incremental reintroduction of tryptophan intake, so not to re-saturate IDO1.
Previously TRP depletion was tried based on the notion that Indoleamine dioxygenase activity could by hyper-activated in ME secondary to Th1 cytokine elevation with an increased production of the neurotoxic NMDA-r ligand quinolinic acid. A prior beneficial response to NMDA-r antagonist memantine and neuroprotective drugs (pregabalin, Flupirtine) for CNS symptoms, but without any appreciable effect on physical endurance supported this notion.

Protocol consisted of the following, but is not based on any specific published protocol:

3 days of dietary tryptophan depletion through consumption of only:

1) dextrose
2) omega oils
3) All essential amino acids (except for Tryptophan)
4) multivitamin and minerals

14-10-18

2 days of tryptophan reintroduction (so far, as of 14-10-18), with TRP exposure on day 1 and 2 @ 25mg 3x daily. (NB. the approximate recommended daily TRP intake appears to be around 200-350 mgs for an approx. 80kg adult). I will update on changes/no changes in coming days.

DISCLAIMER: I do not endorse any one trying this themselves. Typtophan is a dietary essential amino acid and this will deplete serotonin and melatonin. I was only comfortable trying this as I had tried this before with no major adverse effects and it was important to ensure I had not missed a potential benefit.

15-10-18

Titrating TRP intake to 50mgs twice daily (100mgs/D) today.

Aiming to resume a normal (carbohydrates, fats) but relatively low protein diet soon after for some days after. Of course at this point TRP intake cannot further be carefully incremented.

16-10-17

Continuation of a normal diet. Today a normal diet was continued, which wasn't especially high in protein, mostly carbohydrates, bread, some milk.

So far I would have to say overall no major change, but I potentially (hard to definitively tell) felt ever so slightly better during the full tryptophan deprivation compared to now. Maybe this is due to reduced serotonin, but 5Ht2A/2C antagonist (mirtazapine) does not have a similar effect with chronic or acute administration (neither with or without the profound hypnotic effect that persists for many months initially).

I considered whether adding ENADA NADH would help reset the trap more effectively but decided against adding additional B3 or NADH to multivitamin. Perhaps I have resumed TRP intake too rapidly.

 

[Badpack]

Interesting read, but i dont think its very helpful. Once Tryptophan is in the cell, it never gets out again. And if the cell is saturated with it, and without the work of ido2 you wont get ride of it. You need medication to decrease the trypto levels so that ido1 works again or activate the ido2 levels.Starvation wont do enough, maybe even kill you because of the serotonin levels.

Btw. if i remember correctly from the symposium, you would need to starve yourself for 6-8 weeks from all tryptophan to lower the levels in the cell that way. At that point you would be dead from missing serotonin.

 

[energyoverload]

rve yourself for 6-8 weeks from all tryptophan to lower the levels in the cell that way. At that point you would be dead from m

Interesting, so by that method maybe a long term low tryptophan diet in parallel with a drug to redirect amount of intracelullar substrate available for IDO could be of use - e.g. something that activates tryptophan hydroxylase.

Previously when I used BCAAs in conjuction with foods very low in tryptophan - I added 5htp and p-5-p at one point to determine any changes possibly due to lower serotonin.

Maybe a long term low, tryptophan diet combined with 5htp + p-5-p could be a better strategy for intracellular TRP depletion.

 

[Badpack]

i think i wouldnt mess with it for now. And thats from someone who bought Sirolimus and Rituximab in the past just to do nothing for me. But this is on another level. This can outright kill you if done wrong at home.

 

[JES]

It could also remain a possibility, at least to my layman's understanding, that the changes observed in tryptophan levels are not a result of a block but rather a switch as a protective mechanism against some kind of bigger threat. A similar switch was observed by the Norwegian researchers where the body is using amino acids instead of glucose as fuel. If this is the case and it's not a metabolic block, but for example a trypanosoma infection, then attempting to reduce tryptophan could make things worse for us.

 

[Badpack]

You could be right, but than it begs the question, why is the ido2 activity low. And the metabolites that follow tryptophan are also low. Which means its not processed at all.

 

[Murph]

A little bit more evidence I found on possible consequences of high intracellular tryptophan. It could hyperactivate the mTor pathway.

Amino acid transport and mTOR signalling


Elevated amino acid availability signals via mTOR and culminates in increased cellular translation rates.


With respect to TOR signalling, many studies have focused on the potent stimulatory effects of leucine, and several lines of research have implicated the intracellular accumulation of this amino acid in signal initiation [53,182]. Leucine is transported into most mammalian cells by System L, but, in mammalian studies, mTOR signalling is typically much more sensitive to leucine than to other closely related System L substrates such as valine and isoleucine [41,183,184].

Using a combination of amino acid microinjection and System L transporter overexpression techniques in Xenopus laevis oocytes, our group has been able to demonstrate that only under circumstances where amino acid concentrations are increased within the cytoplasm do they activate the TOR pathway [182].

Overexpression of System L confers sensitivity to extracellular amino acids only inasmuch as it facilitates their delivery to the cytosol. Such evidence indicates an intracellular localization for an amino acid sensor upstream of the TOR pathway in X. laevis oocytes, but also highlights the importance of plasma-membrane transporters as conduits for amino acid delivery to the intracellular receptor mechanism. Our evidence is also consistent both with the proposal that the size of the intracellular free amino acid pool regulates mTOR signalling (given that aminoacyl-tRNA composition may not be significantly affected by short-term amino acid deprivation [22]) and the demonstration that competitive inhibitors of amino acid transport inhibit amino-acid-induced activation of mTOR in human Jurkat cells [185]. Injected amino acids activating the TOR pathway in X. laevis oocytes included leucine, tryptophan, phenylalanine, arginine and lysine, whereas glutamine, glutamate, proline and alanine were relatively ineffective.

source


I found this because I was wondering if maybe there was any link from the metabolic trap to our known problems with cellular membrane transport, (in particular calcium). And I came across the whole field of amino acid transporters. Phair's hypothesis certainly wouldn't exclude a dysfunctional tryptophan transport mechanism, whether it was overxcited at uptaking trp into cells, or not good enough at dumping it out.

 

[dreamydays]

Well i'm still alive on the low tryptophan diet, but no changes in ME or really anything. It's been 11 days now and not felt any need for 5HTP supplementation. I would guess i'm getting about 25-60mg a day and the RDA is about 250-300mg

 

[dreamydays]

The MTOR link and sirolimus is interesting. A medication I may consider adding at some point.

 

[Badpack]

Even low tryptophan diet should do nothing for you, you need absolut 0 tryptophan for weeks, thats what i said is the only thing that would help you from a nutrition side. And that is what would kill you.

 

[dreamydays]

Even low tryptophan diet should do nothing for you, you need absolut 0 tryptophan for weeks, thats what i said is the only thing that would help you from a nutrition side. And that is what would kill you.

Badpack, I appreciate your suggestion. My intake is low and I am having enough other aminos. I don't have any symptoms of low serotonin but have had short spells of fatigue which is a little different than what I would normally have. I have 5-HTP supplements but don't feel any need to take them. I don't understand your certainty when it comes to this matter when its pretty new to the ME discussion. Also my NAD+ and Niacin supplementation doesn't seem to make a tangible difference. I must have low serum levels now so less new tryptophan is available to get into cells, so if they are clearing it but at a rate so slow its negligible as IDO2 has failed... The lack of new tryptophan to uptake must help eventually? (and we are talking weeks/months).

 

[Badpack]

Im not certain on this at all, i just take the given information that we have at this point from the symposium from Phair. And he showed us the tryptophan curves. So i go from there with some knowledge about medicine. Your goal needs to be to get completely rid of tryptophan in the serum. Because otherwise the cells arent in the mood to let tryptophan go. Its not natural from a cell to give nutrients away, there are no natural pathways for that. So you would need a high
diffusion coefficient. But the problem is, so it seems, the ido pathway. That means serotonin still is produced (thats a good thing otherwise this illness would kill you in an instant).

If you are really in a need to try it right now, i would suggest 0 trypto + somthing like Sirulismus/Ibuprofen (200mg every 4-6h) to further block the cell trypto intake + 5-htp for serotonin for at least 3 months.

But in the end we dont even know if this is all really relevant. Because if you look up other studies. Many other autoimmun diseases have the same kynurenin problem. Im way more on the g-coupled AAks. Thats the real Problem in my eyes.

 

[raghav]

Can we know how many existing medicines have been tried on the nanoneedle ?