Linking Exercise, Immune activation, Pain and PEM flares and Connective tissue degradation AND female dominance

[dejurgen]

FIRST (and very messy) VERSION, need to give short summary and sleep now. I will reread later, post now without proofreading before computer crashes or something. Short summary will be next post after this one.


After reading https://www.healthrising.org/blog/2025/09/20/long-covid-missing-opportunity/, and opening one of the research papers linked in the blog, I think I managed to fill in a few important blanks connecting some major parts of our set of disaesses.

It is still of "brainstorming quality", so prone to plenty of need for adjustments and corrections later. Yet I feel I must write this down now. My brain is sort on fire now. I does fit in some ideas I am currently working on though.



The paper:
Title "Heightened innate immunity may trigger chronic inflammation, fatigue and post-exertional malaise in ME/CFS"

Heightened innate immunity may trigger chronic inflammation, fatigue and post-exertional malaise in ME/CFS - PMC

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is characterized by unexplained fatigue, post-exertional malaise (PEM), and cognitive dysfunction. ME/CFS patients often report a prodrome consistent with infection. We present a ...

pmc.ncbi.nlm.nih.gov

Figure 2; blue is upregulated, orange downregulated. Note: it is not just a ratio of healthy versus ME/CFS, but a statistical indication of how important the up / downregulation is.

=> At rest / before exercise (fig2a): glucuronic acid is (barely second after the most important one called 1-methylgalactose) is the most significant raised metabolite in ME/CFS of nearly 1000 measured in plasma.

=> By my memory, glucuronic acid is a good anti-oxidant but it can *and will* give plenty of pain mainly in joints when elevetad.

=> 24 h after exercise (fig2b): glucuronic acid is the most significant raised metabolite in plasma, well above all others, of nearly 1000 measured in plasma.

I saw that after looking to figure 1, where it sort of showed an image:

=> Test to determine immune response were done with "Staphylococcus aureus enterotoxin type B (SEB), heat-killed Candida albicans (HKCA), lipopolysaccharide (LPS) and polyinosinicolycytidylic acid (poly I:C)"; reaction to the last one is at first sight barely different from healthy controls versus ME/CFS (fig1f). poly I:C is a TLR3 activator (closely related to activation by a major class of virusses, note some virusses also trigger TLR2 and 4 on plus).

=> Staphylococcus aureus enterotoxin typ B is (although only few info pointing to it, so not that strong on the radar) a TLR 2 and or TLR4 receptor trigger. That TLR4 is a major trigger on all sorts of monocytes (innate immune cells):

Staphylococcus aureus enterotoxin B disrupts nasal epithelial barrier ...​

Concerning upstream mechanisms responsible for TJ defects, it was shown that enterotoxins released by S. aureusactivate TLR2 and/or TLR4

=> Above info is fairly weak, but Staphylococcus aureus enterotoxin also is a strong activator of T-cell receptor:

Frontiers | Binding of Staphylococcal Enterotoxin B (SEB) to B7 ...​

The inflammatory activity of staphylococcal enterotoxin B (SEB) relies on its capacity to trigger polyclonal T-cell activation by binding both T-cell receptor (TCR) and costimulatory receptor CD28 on T cells and MHC class II and B7 molecules on antigen presenting cells (APC).

=> Candida albicans is a strong activator of TLR2/TLR4:
https://duckduckgo.com/?q=Candida albicans tlr+site:www.nature.com&t=ffab
https://www.nature.com › articles › s41467-019-08950-3

A small secreted protein triggers a TLR2/4-dependent inflammatory response during invasive Candida albicans infection​

=> Candida albicans is a B-cell activator as well:

Frontiers | B Cell Recognition of Candida albicans Hyphae via TLR 2 ...​

In this study, we show that C. albicans hyphae but not yeast, as well as fungal cell wall components, directly activate B cells via MyD88 signaling triggered by Toll- like receptor 2, leading to increased IgG1 production.

=> LPS is mainly known as a TLR4 receptor activator (plenty of links to be found), but also a TLR2 relation:


PubMed
https://pubmed.ncbi.nlm.nih.gov › 22523073

Toll-like receptor 2 is required for LPS-induced Toll-like receptor 4 ...​

TLR2 plays a dual role in the induction of intracellular signals that impair MTAL function, both through cooperation with TLR4 to mediate ERK signaling by LPS and through a TLR4-independent signaling pathway activated by Gram-positive bacterial ligands.

=> LPS also activates T and B-cells

T Cell Stimulation In Vivo by Lipopolysaccharide (LPS) - PMC​

Lipopolysaccharide (LPS) from gram-negative bacteria causes polyclonal activation of B cells and stimulation of macrophages and other APC. We show here that, under in vivo conditions, LPS also induces strong stimulation of T cells. As manifested by ...

=> Now all of the above made me look at the link between glucoronic acid and TLR4 (and related to monocytes such as macrophages, (brain) microglia and other immune cells); the other receptors and cell types follow later:

from https://en.wikipedia.org/wiki/Glucuronic_acid:

Role in disease​

Glucuronic acid, as well as the glucuronidated metabolite of ethanol, ethyl glucuronide (ETG), acts on toll-like receptor 4 to aggravate both acute and chronic inflammatory conditions and increases the perceived severity of pain in patients with chronic pain conditions, via up-regulation of the production and release of endogenous inflammatory signaling molecules within the body. Long-term agonism of the TLR4 receptor (such as that which occurs from GCA, ETG, and opiates) results in chronically painful conditions being perceived as considerably more severe than they did previously, while pre-existing, tolerable yet occasionally painful activities can become more painful than before and will begin to be aggravated by briefer and less physically demanding activities. It also can cause equally painful responses to decreasingly noxious (irritating) stimuli, eventually resulting in considerable agony from stimuli which would not cause any amount of pain to most individuals.[6]

=> I know many scientists look down on Wikipedia, but link [6] is serious:
Lewis SS, Hutchinson MR, Zhang Y, Hund DK, Maier SF, Rice KC, Watkins LR (2013). "Glucuronic acid and the ethanol metabolite ethyl-glucuronide cause toll-like receptor 4 activation and enhanced pain". Brain, Behavior, and Immunity. 30: 24–32. doi:10.1016/j.bbi.2013.01.005. PMC 3641160. PMID 23348028.

=> (nice note from the paper: "

3.3. Experiment 2B: In vitro GA, EtG and EtOH induced increases in SEAP expression are blocked by the TLR4 antagonists LPS-RS and (+)-naloxone")​

Meaning TLR4 receptor antagonists and naloxone (related, as in somewhat similar behavior as, to naltrexone and ldn) reduce the effect of glucuronic acid in triggering the immune system so much.

=> Also from the paper
"TLR4 inhibition reduces the rewarding affects of morphine and cocaine (Galer et al., 2012, Hutchinson et al., 2012) and reduces sedative and ataxic effects of ethanol (EtOH) (Wu et al.)."
Meaning EtOH (alcohol) also hammers the TLR4 recptor. Many ME/CFS patients react badly to alcohol. Also, Reducing ethanol from binding to TLR4 reduces ataxia caused by ethanol. And glucuronic acid is also a strong TLR4 activator hence it makes sense that excess glucuronic acid can cause / worsen ataxia. Note: I am one of many ME/CFS patients whose walking gets *very* bad *very* quickly when crashing... and glucuronic acid is increased a lot after 24h (but not measured in between exercise and 24h laters in this research).

Note: no research points out excess glucuronic acid and ataxia YET. What one does not search for...

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NOW: where could this excess glucuronic acid come frome?
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=> Luckily I had a clue, and came quickly to hyaluronic acid (coming from oxidative stress breaking connective tissue down):

=> Hyaluronic acid is composed of glucosamine and glucuronic acid:

Hyaluronic Acid in the Third Millennium - PMC

Since its first isolation in 1934, hyaluronic acid (HA) has been studied across a variety of research areas. This unbranched glycosaminoglycan consisting of repeating disaccharide units of N-acetyl-d-glucosamine and d-glucuronic acid is almost ...

pmc.ncbi.nlm.nih.gov

Abstract​

Since its first isolation in 1934, hyaluronic acid (HA) has been studied across a variety of research areas. This unbranched glycosaminoglycan consisting of repeating disaccharide units of N-acetyl-d-glucosamine and d-glucuronic acid is almost ubiquitous in humans and in other vertebrates. HA is involved in many key processes, including cell signaling, wound reparation, tissue regeneration, morphogenesis, matrix organization and pathobiology, and has unique physico-chemical properties, such as biocompatibility, biodegradability, mucoadhesivity, hygroscopicity and viscoelasticity.

From https://en.wikipedia.org/wiki/Hyaluronic_acid, but again I searched for "real scientific papers" later:

"While it is abundant in extracellular matrices, hyaluronan also contributes to tissue hydrodynamics, movement, and proliferation of cells and participates in a number of cell surface receptor interactions, notably those including its primary receptors, CD44 and RHAMM. Upregulation of CD44 itself is widely accepted as a marker of cell activation in lymphocytes. Hyaluronan's contribution to tumor growth may be due to its interaction with CD44. Receptor CD44 participates in cell adhesion interactions required by tumor cells.[16]

Although hyaluronan binds to receptor CD44, there is evidence hyaluronan degradation products transduce their inflammatory signal through toll-like receptor 2 (TLR2), TLR4, or both TLR2 and TLR4 in macrophages and dendritic cells. TLR and hyaluronan play a role in innate immunity."

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=> BAM: that is connecting multiple types of epithelial surfaces, connective tissues adaptive immunity (B-cell and T-cell as lymphocytes) and innate immunity with TLR2 and 4 activation in macrophages (including microglia in the brain and dendritic cells)
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from https://en.wikipedia.org/wiki/CD44:

Function​

CD44 participates in a wide variety of cellular functions including lymphocyte activation, recirculation and homing, hematopoiesis, and tumor metastasis.

CD44 is a receptor for hyaluronic acid[7] and internalizes metals bound to hyaluronic acid[8][9] and can also interact with other ligands, such as osteopontin, collagens, and matrix metalloproteinases (MMPs). CD44 function is controlled by its posttranslational modifications.

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A remaining problem: hyaluronic acid turnover in the human body is high. In healthy people, already a lot of it needs to be broken down each day. Why could it and is break down products (glucuronic acid) then be a lot higher in ME/CFS? How could breakdown of it cause disease if breakdown is already high in healthy people?
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[dejurgen]

Hyaluronic Acid in the Third Millennium - PMC

Since its first isolation in 1934, hyaluronic acid (HA) has been studied across a variety of research areas. This unbranched glycosaminoglycan consisting of repeating disaccharide units of N-acetyl-d-glucosamine and d-glucuronic acid is almost ...

pmc.ncbi.nlm.nih.gov

with title "

Hyaluronic Acid in the Third Millennium"​

"In the human body, the total content of HA is about 15 g for a 70-kg adult [86]. HA is prevalently distributed around cells, where it forms a pericellular coating, and in the extracellular matrix (ECM) of connective tissues [61,82]. Approximately 50% of the total HA resides in the skin, both in the dermis and the epidermis [82]. Synovial joint fluid and eye vitreous body, being mainly composed of ECM, contain important amounts of hyaluronan: 3–4 mg/mL and 0.1 mg/mL (wet weight), respectively [61,82]. Moreover, HA is also abundant in the umbilical cord (4 mg/mL), where it represents the major component of Wharton’s jelly together with chondroitin sulfate [87,88]. The turnover of HA is fast (5 g/day) and is finely regulated through enzymatic synthesis and degradation [86]."

=> Of the 15 gram in the human body, 5 gram each day is "turned over" eg destroyed and produced anew.

The answer is given in the same paper:

"The primary structure of HA is a linear chain containing repeating disaccharide units linked by ß-1,4-glycosidic bonds. Each disaccharide consists of N-acetyl-d-glucosamine and d-glucuronic acid connected by ß 1,3-glycosidic bonds"

=> Hyaluronic acid is a long chain of [N-acetyl-d-glucosamine and d-glucuronic acid] linked after each other again and again through a single oxygen atom each time, see also figure 1. It therefore has the potential to be broken down along one or more weak links in that moleucle, in "countless (barely controled) fragments" due to things like oxidative stress. Remember that one of its components, glucoronic acid, is a good anti-oxidant hence it is easily chemically modified by ROS. This potential "falling apart of hyaluronic acid from connective tissue due to ROS / ROS from immune activation in plenty of pieces may create plenty more particles scattered all over our bodies then a controled degradation by enzymes.

=> From the same paper:

3.3. HA Degradation in the Human Body​

"HA degradation in the human body is accomplished by two different mechanisms: one is specific, mediated by enzymes (hyaluronidases (HYAL)), while the other is nonspecific, determined by oxidative damage due to reactive oxygen species (ROS) (Figure 3). Together, HYAL and ROS locally degrade roughly 30% of the 15 g HA present in the human body. The remaining 70% is catabolized systemically: hyaluronan is mostly transported by the lymph to the lymph nodes, where it is internalized and catabolized by the endothelial cells of the lymphatic vessels. Additionally, a small part of HA is carried to the bloodstream and degraded by liver endothelial cells [50]."

=> There is enzymatic deconstruction of HA and deconstruction due to ***ROS***. Now excess immune activation due to exercise in us (in an already prone state, working on that part later) is enough to break down plenty of hyaluronic acid parts of connective tissues (including those surrounding our blood vessels) in plenty of small fragments.

=> Still from the same paper:
"HMW hyaluronan can also be naturally degraded in the organism by ROS, including superoxide, hydrogen peroxide, nitric oxide, peroxynitrite and hypohalous acids, which are massively produced during inflammatory responses, tissue injury and tumorigenesis [60,109]. The depolymerization of HA occurs through mechanisms of the reaction that are dependent on the ROS species, but always involve the scission of the glycosidic linkages [86,110]."

=> Seems ROS always "cuts" the glycoside linkages meaning separating whole [N-acetyl-d-glucosamine and d-glucuronic acid], hence not modifying the d-glucoronic acid yet. This hence leaves d-glucoronic acid itself intact as part of a (whole lot of) N-acetyl-d-glucosamine and d-glucuronic acid groups(s). Those later may or may not be further split in two leaving (plenty of) "complete", unaltered glucuronic acid groups and glucosamine groups for further processing.

Still from the paper:
"Studies have shown that oxidation-related inflammatory processes, determining HA fragmentation, can increase the risk of injury in the airways and determine loss of viscosity in synovial fluid, with consequent cartilage degeneration, joint stiffness and pain [111,112,113]. ROS-induced degradation of HA might suggest why its antioxidant activity is one of its possible roles in reducing inflammation; however, so far, this biological function of HA has only been hypothesized, as it is not sufficiently supported by experimental data."

Still from the paper:

"Molecular mass and circumstances of synthesis/degradation are the key factors defining HA’s biological actions [50,51,100]. Indeed, high molecular weight (HMW) and low molecular weight (LMW) hyaluronan can even display opposite effects [51,60],"

and

"Extracellular HMW HA (≥106 Da) is anti-angiogenic, as it is able to inhibit endothelial cell growth [51,60,114]. Additionally, due its viscoelasticity, it acts as a lubricating agent in the synovial joint fluid, thus protecting the articular cartilage [115]. HMW HA has also important and beneficial roles in inflammation, tissue injury and repair, wound healing and immunosuppression: it binds fibrinogen and controls the recruitment of inflammatory cells, the levels of inflammatory cytokines and the migration of stem cells [60,93,114]."

and

"During some environmental and pathological conditions, such as asthma, pulmonary fibrosis and hypertension, chronic obstructive pulmonary disease and rheumatoid arthritis, HMW HA is cleaved into LMW HA (2 × 104–106 Da), which has been shown to possess pro-inflammatory and pro-angiogenic activities [51,100]. Indeed, LMW hyaluronan is able to stimulate the production of proinflammatory cytokines, chemokines and growth factors [51] and to promote ECM remodeling [50]. Moreover, LMW HA can also induce tumor progression, exerting its influence on cells [51,116] and provoking ECM remodeling."

=> Long chains of hyaluronic acid are more anti-inflammatory. Short fragments of hyaluronic acid are more pro-inflammatory. That makes a lot of sense: A molecule of for example a thousand lineary linked parts won't realisticaly be able to bind to / trigger more then a few immune cells at once. A "fragmentation bomb" of hundreds of small hyaluron fragments (produced by ROS) from that same molecule will be able to bind and influence (activate) to far more immune cells.

=> One long strand of lineary chained hyaluronic acid in good health versus hundreds or thousand of fragments of glucuronic acid containing molecules formed from it under heavy ROS / immune activation

Remember (written above): each glucoronic acid molecule can activate TLR4
Lewis SS, Hutchinson MR, Zhang Y, Hund DK, Maier SF, Rice KC, Watkins LR (2013). "Glucuronic acid and the ethanol metabolite ethyl-glucuronide cause toll-like receptor 4 activation and enhanced pain". Brain, Behavior, and Immunity. 30: 24–32. doi:10.1016/j.bbi.2013.01.005. PMC 3641160. PMID 23348028.

AND: a small series of unmodified but cut out [N-acetyl-d-glucosamine and d-glucuronic acid] (meaning []-[]-[]-[] a number of those units lineary linked after each other) still is a molecule of hyalorunic acid, only a smaller one. Hyaluronic acid is like a long piece of wire. Cut it in a hundred pieces and you the pieces are still wires with the properties of wires, only much smaller ones. And (written above): each piece of glucoronic acid can activate TLR2, TLR4 and affect B-cells and T-cells:

From https://en.wikipedia.org/wiki/Hyaluronic_acid, but again I searched for "real scientific papers" later:

"While it is abundant in extracellular matrices, hyaluronan also contributes to tissue hydrodynamics, movement, and proliferation of cells and participates in a number of cell surface receptor interactions, notably those including its primary receptors, CD44 and RHAMM. Upregulation of CD44 itself is widely accepted as a marker of cell activation in lymphocytes. Hyaluronan's contribution to tumor growth may be due to its interaction with CD44. Receptor CD44 participates in cell adhesion interactions required by tumor cells.[16]

Although hyaluronan binds to receptor CD44, there is evidence hyaluronan degradation products transduce their inflammatory signal through toll-like receptor 2 (TLR2), TLR4, or both TLR2 and TLR4 in macrophages and dendritic cells. TLR and hyaluronan play a role in innate immunity."

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Side note: the other highly relevant upregulated metabolite in ME/CFS plasma at rest is another one hammering the TLR2/TLR4 system:

https://www.sciencedirect.com/science/article/pii/S0144861724012785

with title "

Methyl-esterification, degree of polymerization and ∆4,5-unsaturation of galacturonic acid oligosaccharides as determinants of immunomodulation"​

"Both methyl-esterified and non-methyl-esterified galacturonic acid oligosaccharides with a saturated non-reducing end (degree of polymerization 1–10) significantly induced cytokine production by THP-1 macrophages and directly activated TLR2 and TLR4 in transfected HEK-293 cells, even when accounting for minor endotoxin contamination. In contrast, both methyl-esterified and non-methyl-esterified galacturonic acid oligosaccharides with a Δ4,5-unsaturated non-reducing end (degree of polymerization 1–7) did not activate TLR2 and TLR4 and led to significantly reduced cytokine production (p < 0.05), suggesting Δ4,5-(un)saturation as a pivotal factor for immunomodulation by galacturonic acid oligosaccharides. "



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Now from another paper Cort linked in the blog:

Urine Metabolomics Exposes Anomalous Recovery after Maximal Exertion in Female ME/CFS Patients - PMC

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a debilitating disease with unknown etiology or effective treatments. Post-exertional malaise (PEM) is a key symptom that distinguishes ME/CFS patients. Investigating changes in the ...

pmc.ncbi.nlm.nih.gov

The MOST and massively upregulated excreted molecule (out of about 250 analyzed) is 11-ketoetiocholanolone glucoronide

https://en.wikipedia.org/wiki/Etiocholanolone_glucuronide is (*VERY likely*) either the same or a very much related molecule this
11-ketoetiocholanolone glucoronide can be transformed in.

=> That is the composition of etiocholanolone and glucoronide

Now per the much above mentioned paper, glucoronide is high at rest in ME/CFS and goes (very likely) even higher 24h post exertion.

And according to https://en.wikipedia.org/wiki/Etiocholanolone_glucuronide:

"Etiocholanolone glucuronide (ETIO-G) is an endogenous, naturally occurring metabolite of testosterone.[1][2] It is formed in the liver from etiocholanolone by UDP-glucuronyltransferases.[1] ETIO-G has much higher water solubility than etiocholanolone and is eventually excreted in the urine via the kidneys.[1][2] Along with androsterone glucuronide, it is one of the major inactive metabolites of testosterone.[3][4]"

=> Now this etiocholanolone produces, together with UDP-glucuronyltransferase (easy enough made from UDP and glucuronide IMO) something that is much more soluble in water and hence can be removed out of the plasma and dumped into urine.

now https://en.wikipedia.org/wiki/Etiocholanolone:
Etiocholanolone, also known as 5β-androsterone, as well as 3α-hydroxy-5β-androstan-17-one or etiocholan-3α-ol-17-one, is an etiocholane (5β-androstane) steroid as well as an endogenous 17-ketosteroid that is produced from the metabolism of testosterone. It causes fever, immunostimulation, and leukocytosis, and is used to evaluate adrenal cortex function, bone marrow performance, and in neoplastic disease to stimulate the immune system. Etiocholanolone is also known to be an inhibitory androstane neurosteroid,[1] acting as a positive allosteric modulator of the GABAA receptor,[2] and possesses anticonvulsant effects.

=> etiocholanolone is made from (a metabolite of) testosteron.

=> Men have very likely plenty more of it.
=> It is able to "catch and remove" IMMUNE SYSTEM HAMMERING glucuronide from the plasma.
=> Having more testosteron hence very likely produces more etiocholanolone and with it helps clearing this highly inflammatory (if in excess) glucuronide MUCH more quickly in men versus women
=> When it is used / removed for binding glucuronide, it drops and with it fever (body temperature), immunostimulation (less "normal" reaction of immune system to exercise in ME/CFS) and working as an inhibitory neurosteroid, GABA enhancer and anticonvulsant drops (increasing exitory brain and convulsions / spams as seen in ME/CFS)

=> Etiocholanolone, a breakdown product of testosterone, binds to glucuronic acid (the highly problematic molecule in this hypothesis) and removes is into the urine. Hence having more testosterone can dampen a quick rise in collagen / hyaluronic acid breakdown due to ROS due to immune activation VICIOUS circle A LOT FASTER, helping to explain the big gap in prevalence among men versus women for ME/CFS, FM and Connective tissue disseases.

 

[dejurgen]

The shorter version, still not proofread and with a rather fatigued brain :

The first major part comes from the paper:
Title "Heightened innate immunity may trigger chronic inflammation, fatigue and post-exertional malaise in ME/CFS"

=> Figure 1 shows a number of responses to different immune stimuli. It sort of looked to me at first sight that TLR2/TLR4 activators hammer ME/CFS cells a lot more then a simple viral part does. Yet for some activators there is only modest evidence for TLR2/TLR4 activation but it shows T-cell activation.

=> Figure 2a shows glucuronic acid to be a major elevated plasma metabolite (out of nearly 1000) at rest in ME/CFS and even more so 24 hours after exertion.

=> Combining both plus remembering that glucuronic acid can cause quite a bit of joint pain, I combined those.

=> Glucuronic acid turns out to be quite a potent TLR2/TLR4 activator. TLR2 and TLR4 are receptors that are common on many types of cells, including macrophages (and there brain variant called microglia) and B-cells.

=> Interesting, the paper says that naloxone, a TLR4 antagonist much like LDN reduces the inflammatory effect of glucuronic acid.

=> Glucuronic acid is a part of the molecule hyaluronic acid. That in turn is an important part of all sorts of connective tissue including tissue surrounding our blood vessels and giving it good support.

=> Humans have about 15 grams of hyaluronic acid, of which each day about 5 grams is turned-over / renewed. That raises the question how glucuronic acid in ME/CFS plasma could be so elevated *if that elevation came from breakdown of the hyaluronic acid in our connective tissue* if it already has such high percentual turnover in healthy people.

=> Hyaluronic acid is a long chain of [N-acetyl-d-glucosamine and d-glucuronic acid] building blocks after each other, each linked by a single atom to each other.

=> Hyaluronic acid is like a long wire. Cut it in a hundred smaller pieces, and each of the pieces is still a wire with the properties of a wire. All pieces are just smaller.

=> A paper details that hyaluronic acid, with its high renewal rate, can be broken down enzymatically (and in an ordered fashion) as well as through oxidative stress (ROS).

=> Oxidative stress always breaks it on the glycoside bond according to the paper, leaving "entire" but smaller pieces of hyaluron after cutting it in parts. The parts are not modifed by ROS, only the length of the chain is modified. This leaves most of the properties of the small parts of hyaluronic acid still intact.

=> Hyaluronic acid also has a strong proven effect on TLR2, TLR4, B-cells and T-Cells. In fact, there is a dedicated receptor called the CD44 receptor for hyaluronic acid on immune cells.

=> The paper says that long strands of hyaluronic acid are more anti-inflammatory, and short strands of hyaluronic acid more pro-inflammatory.

=> Simple geometry says that it is VERY likely that one long strand of hyaluronic acid likely can't bind to / activate more then a few immune cells total. Hundreds or thousands of pieces of hyaluronic acid, still maintaining most of the properties of the longer strand, can easily be dispersed and activate much more immune cells. As they are very small fragments, they can spread quickly all over the body.

This leaves healthy versus ME/CFS. Weakened cells and immune systems can, in ME/CFS, trigger a strong immune response (also) near connective tissues. With too much oxidative stress and/or too few anti-oxidant defenses, that risks to quickly break down parts of the *already weakened* / "cheesehole" connective tissues into copious amounts of small pieces of hyaluronic acid and glucuronic acid, spreading as the splinters of a splinter bomb throughout our bodies and triggering immune cells all around the body. Overdoing it in one part of the body, activating such breakdown of connective tissue, could spread the fragments in minutes all around the body creating inflammatory flares from ankles over gut to brain and leaving connective tissue damage (including weak blood vessels) as a "residue gift".

=> One long strand of lineary chained hyaluronic acid in good health versus hundreds or thousand of fragments of glucuronic acid containing molecules formed from it under heavy ROS / immune activation
Now take the other linked paper:
Title: "Urine Metabolomics Exposes Anomalous Recovery after Maximal Exertion in Female ME/CFS Patients"

The most upregulated metabolite, among about 250 analyzed, in urine is 11-ketoetiocholanolone glucoronide.

=> I haven't been able to check yet, but that sounds a lot like a variant of (or something easily converted into) etiocholanolone glucuronide. Now etiocholanolone produces, together with UDP-glucuronyltransferase (easy enough made from UDP and glucuronide IMO) something that is much more soluble in water and hence can be removed out of the plasma and dumped into urine.

=> Etiocholanolone hence sounds as a rather good thing to clear this (at excessive amounts) highly inflammatory glucuronide from our bodies.

=> Etiocholanolone is one of the main breakdownproducts of testosterone, and it is known as an inhibitory neurosteroid, improve GABA effectiveness and be anticonvulsant.

=> When binding available etiocholanolone to glururonic acid to try and excreed it, there is less etiocholanolone available increasing brain hyperexcitability and convulsions / spams as seen in ME/CFS when crashing. Also: men obviously have much more of it then women to start with.

=> Then why do men still have a chance to get down with ME/CFS, FM, connective tissue disorders if they have so much more of this protective etiocholanole? My best guess at the moment is that ethiocholanole only clear one component of the "fragmentation bomb" I theorize: glucuronic acid. The other thing hammering the immune system, plenty of small fragments, probably can only be removed if hyaluronic acid first is broken down into glucuronic acid and glucosamine. Only then can the other "fragment" be removed quickly in men.

=> In simpler words: It may take plenty of time for women to clear out both glucuronic acid and hyaluronic acid "bomb fragments" hammering the immune system while men only / mainly have to deal with excess hyaluronic acid "bomb fragments". Both can hammer the immune system and create a vicious circle (by hammering the immune system to break down more connective tissue that produces more "bomb fragments" that can hammer the immune system more... Since both glucuronic acid and hyaluronic acid trigger the immune system in similar *but somewhat different* ways, it is reasonable to see a different immune activation profile in women versus men on top of the increased vulnearbility for this vicious circle.

=> Etiocholanolone, a breakdown product of testosterone, binds to glucuronic acid (the highly problematic molecule in this hypothesis) and removes is into the urine. Hence having more testosterone can dampen a quick rise in collagen / hyaluronic acid breakdown due to ROS due to immune activation VICIOUS circle A LOT FASTER, helping to explain the big gap in prevalence among men versus women for ME/CFS, FM and Connective tissue disseases.

 

[dejurgen]

I think I figured out another important piece of the puzzle:

The two main elevated plasma metabolites in ME/CFS at rest are Wikipedia(Methyl-α-D-galactose) and glucoronic acid according to the https://pmc.ncbi.nlm.nih.gov/articles/PMC12408823/ paper with title "Heightened innate immunity may trigger chronic inflammation, fatigue and post-exertional malaise in ME/CFS"

Looking at https://en.wikipedia.org/wiki/File:Methyl-alpha-D-galactose.svg and holding https://en.wikipedia.org/wiki/File:Glucosamine_Structural_Formulae_V.1.svg next to it, it looks like that:

a) The NH2 group in the bottom middle of glucosamine has been replaced by an OH group.
b) The OH group in the bottom right has been replaced by an OCH3 group.

a) looks close to a deanimation. See https://en.wikipedia.org/wiki/Deamination.
In a deanimation, a common biological reaction, ammonia is removed and in the wikipedia example water is added. Here an NH2 group is removed and and OH group is added. Mathematically:
NH2 - NH3 + H2O = -H + H2O = HO = OH group

In English: have an NH2 group, do what deanimation reactions would do (remove ammonia and add water or -NH3 + H2O) and you have just enough atoms left to add an OH group in the place where you removed the NH2 group.

b) looks a lot like a methylation reaction. For example in the Electrophylic Methylation part of https://en.wikipedia.org/wiki/Methylation, you replace in every example an OH group by an OCH3 group, just as in this molecule.

Then there is the left top OH arm that bends the other way in both molecules, but it is present in both at the same position. That is a conformational change that is also common in biochesmistry.

=> The 1-methyl-galactose looks to have high chance of being a degradation product of glucosamine.

=> As written in previous post, it also is a potent immune activator.

=> It will, in this hypothesis, be also part of cleaning up the hyaluronic acid fragments. So there will be plenty of it (as seen in figure 2a)

=> Another important thing: the 1-methyl-galactose levels where NOT increased 24h after exercise compared to healthy controls. They do not even show up on figure 2b. That is important and rather remarkable. It IMO indicates that both in healthy controls and ME/CFS 1-methyl-galactose is likely elevated (need to look into raw data, didn't yet, exhaustion...) (as I presume that exercise does not let dissapear the excess seen in ME/CFS at rest; since fig2b shows ratios, it then makes sense that it raised in healthy controls 24h after exercise to match ME/CFS levels ?as part of normal inflammatory response to exercise?)

=> If correct assumption (need to verify), then ME/CFS patients are not efficient at cleaning out the remaining 1-methyl-galactose after some long time of rest.

=> That may point to increased continuous (or at least every day) destruction of hyarulonic acid / connective tissue due to increased immune activity and decreased oxidative stress defenses. Plus possibly decreased glucosamine / 1-methyl-galactose clearance rates.

=> Methylation is often part of processing chemicals to remove them as waste from the body. Methylation also requires good working mehtylation pathways and enough coblamin (vit b12)

=> The two main metabolites increased (in this research) in ME/CFS at rest versus in healthy people have both a rather strong chance to be break-down products of hyaluronic acid. Hyaluronic acid is found in connective tissue and ROS can break down the glycoside bonds leaving plenty of small fragments of glucuronic acid and 1-methyl-galactose as observed to be the two dominant markers found out of a thousand metabolites in plasma. Plenty of hyaluronic acid fragments, glucuronic acid and 1-methyl-galactose have proven rather strong influence on multiple parts of the immune system. They are small molecules that can be made in very large numbers from a single strand of hyaluronic acid. One of these three components can be cleaned up a lot faster with a breakdown product of testosterone, a hormone obviously higher in men then women. All of this fits ME/CFS and its connection to FM, connective tissue disorders and even migraine being more prominent in women. The symptoms of plenty of hyaluronic acid fragments, glucuronic acid and 1-methyl-galactose show good overlap with what is seen in ME/CFS, FM and connective tissue disorders.

 

[dejurgen]

I am on a roll (and my sleep is broken for the night). I may have got a new angle on the low blood volume paradox:

When I crash, I always need to pee plenty. And I easily tend to (over)breathe even more. Many people / doctors consider both a wrong reaction. The body "should" hold more water and correct via the renin-angotension system and reacts "wrong and paradoxal" and patients "should learn to breath better because there breathing makes them worse".

But: https://link.springer.com/article/10.1134/S0006297906060113
Title "pH-dependent regulation of myeloperoxidase activity"

Note: myeloperoxidase is an enzyme formed by (among others) neutrophils and neutrophil extracellular traps (NETS). It transforms relatively weak oxidant H2O2 into very potent (and highly damaging / inhibiting to mitochondrial respiration) HOCl or hypochlorous acid.

Saying "It is shown that at neutral pH MPO had higher affinity to peroxidase substrate guaiacol: at pH 7.4, chloride ions did not compete with guaiacol up to the concentration of 150 mM. At acidic pH, chlorinating activity of MPO dominates" and "Thus, in the presence of phenolic peroxidase substrate, MPO chlorinating activity can be displayed at acidic pH only. It can lead to elimination of hypochlorite production in normal tissues at neutral pH (7.4) and its enhancement in phagosomes where the pH range is 4.7–6.0."

=> If there is plenty of H202 ("basic oxidative stress molecule"), then presence of myeloperoxidase can produce copious amounts of much more aggressive HOCl or hypochlorous acid. HOCl is often formed in bleach and is highly effective at killing micro-organisms. Copious amounts of it all around our body would be pretty harsh.

=> Now it seems that much of that *might* be prevented by trying to get the liquid in our body (blood plus other water all around the body) less acid / more alkaline and just getting it to neutral or slightly alkaline would already inhibit HOCl production a lot.

One way to do that is: expelling CO2 as well as possible, as that slightly increases acidity. Basically: hyperventilate at rest, hyperventilate like a horse when crashing when the immune system kicks in one more extra gear (and lactic acid potentially is bilding up to increasing blood and tissue acidity).

It gets even better: while removing acidity from the blood and body fluid might be the "goal" of hyperventilating, increased alkalosys incourages the kidneys to try and secrete bicarbonate and dump it in the urine. In order to try and maintain ion balance, that'll require dumping sodium in the urine too. Combined extra NaHCO3 or sodium bicarbonate should be dumped in urine. That may not be easy to detect in tests, as that'll simple draw water from the blood into the urine (diluting the extra sodium bicarbonate). And it'll decrease blood / water content.

Possibly the lungs (hyperventilating) and kidneys (dumping (sodium-)bicarbonate) counteract each other by both being unaware of each others goal. One decreases acidity and one tries to restore it (or better said reduce excess alkality, not increase acidity above the neutral point). But that may not be an error. Doing so seems to be the better way to draw excess CO2 from every bit of liquid outside the blood to first in the alaklic blood and then bind it to sodium to dump it in the urine. IF so, decreasing blood acidity wouldn't be the only goal. Decreasing all tissue acidity would be the goal.

In light of the "collagen destruction" hypothesis, that would make sense as that would reduce immune cells that travelled from the blood into the connective tissue to have lower HOCl production as well and HOCl is likely very effective at destructing hyaluronic acid:

Degradation of hyaluronic acid, poly- and monosaccharides, and model compounds by hypochlorite: evidence for radical intermediates and fragmentation - PubMed

Degradation of hyaluronic acid by oxidants such as HO. and HOCl/CIO- is believed to be important in the progression of rheumatoid arthritis. While reaction of hyaluronic acid with HO. has been investigated extensively, reaction with HOCl/ClO- is less well defined. Thus, little is known about the...

pubmed.ncbi.nlm.nih.gov

with title "Degradation of hyaluronic acid, poly- and monosaccharides, and model compounds by hypochlorite: evidence for radical intermediates and fragmentation "

saying "The detection of increasing yields of low-molecular-weight radical adducts from hyaluronic acid and chondroitin sulphate A with increasing HOCl/ClO-concentrations suggests that formation of the initial nitrogen-centered species on the N-acetylglucosamine rings, and the carbon-centered radicals derived from them, brings about polymer fragmentation."

Rough translation: there seems to be strong indication that HOCl in reality breaks down long pieces of hyaluronic acid (a polymer of smaller building blocks) and creates radical intermediates and fragments from them. Radical intermediates counds like ROS, and fragments like the above described "hyaluronic acid, glucuronic acid and 1-methyl-galactose fragmentation bomb". And hyperventilating to get body fluid acidity down and peeing CO2 bind in sodium bicarbonate out might reduce the formation of HOCl.

 

[dejurgen]

=> Another important thing: the 1-methyl-galactose levels where NOT increased 24h after exercise compared to healthy controls. They do not even show up on figure 2b. That is important and rather remarkable. It IMO indicates that both in healthy controls and ME/CFS 1-methyl-galactose is likely elevated (need to look into raw data, didn't yet, exhaustion...) (as I presume that exercise does not let dissapear the excess seen in ME/CFS at rest; since fig2b shows ratios, it then makes sense that it raised in healthy controls 24h after exercise to match ME/CFS levels ?as part of normal inflammatory response to exercise?)

This may sound as if this methabolite, that also can hammer the immune system, reacts the same in healthy controls versus ME/CFS 24h after exercise. This is not entirely true however:

a) A healthy person may indeed experience a part of the symptoms we have when exhausting himself far too much. He may for example get excruciating pain, loose limb coordination, get brain fogged and feel like and effectively risk falling to the ground on the spot somewhere halfway when stubornly keep trying to finish an iron man (one of the most ridiculy harsh endurance sports ever) without training for it. We may get that when trying to walk 100 meters at a snails pace or going up one flight of stairs. The level of combined effort and time of effort at which this happens for producing the same amount of metabolite is orders of magnitude different.

b) When stopping the effort in a), both healthy controls and ME/CFS patients can take quite some time to recover. The drop in load on all tissue cells excluding the immune cells however massively drops in the healthy person going from stubornly attempting to finish an iron man. With it, the body only mainly sees "aggression" from the immune system remaining during recovery. Getting up from rest to go to the toilet or make a cup of coffee barely breaks this rest. With us, stopping this snails pace 100 meter walk barely (percentage wise, at least in comparison to the healthy person going from exhaustion to rest) decreases the load on much of our tissue cells when going from exhaustion to rest. The "aggression" of the upregulated immune system alone can upregulate the stress and danger signals send from all those non immune tissue cells into the body, compounding with the "aggression" of the upregulated immune system to keep the vicious circle going. Even a small effort like going to the toilet can break our rest and is hard to avoid.

Both differences, a) and b), are enough to cause healthy people recovering to normal health versus us keep being stuck at a very low level of performance and wellbeing. That is also seen in the continued upregulation of glucuronic acid in ME/CFS versus healthy controls at rest.

This view also tells why it seems a rather bad idea to get back to full activities too quickly after an infection (a common pattern in many people) or exhausting oneself again and again before being sufficiently recovered (IMO a likely way into gradual onset ME/CFS, especially when already having slumbering health and immune issues).

Now I am back to trying to recover from this mental marathon effort. I more then feel it and it will take some time.

 

[dejurgen]

For people asking: but what about one of the last promissing hypothesises, the itaconate shunt hypothesis? Is this completely different or another total different hypothesis?

I would say it is quite compatible. (modestly) Increased itaconate is observed in early research in ME/CFS [need to find reference, name of researcher, too tired now]. Monocytes, like macrophages, microglia and even more so dendrites produce copious amounts of itaconate when triggered by TLR4 (and TLR2?) agonists / activators. "Letting explode a hyaluronic acid fragmentation bomb" will spread copious amounts of small molecules excelling at triggering TLR2 and TLR4 receptors. Hence these monocytes would likely be able to produce plenty of itaconate and some itaconate will spill into the bloodstream and non-immune cells.

In addition, the itaconate *shunt* requires coblamin (vitamin B12) to remove a slow degrading itaconate metabolite "capturing, trapping" CoA and making CoA unavailable for the Krebbs cycle of our mitochondria. That (in combination with clearing metabolites of this "fragmentation bomb") has potential to be part of the PEM timeframe / cascade.

Now metabolizing plenty of glucosamine fragments to 1-methyl-galactose (IF that was indeed the source of it and the pathway) for processing and excretion would require a methylation step and a large amount of methylation effort. That also require coblamin (vitamin B12).

Combine both, and vitamin B12 risks to drop in blood, and have to "divide its workings" amoung two simultaneous happening "PEM related pathways". More stress on vitamin B12 / the methylation pathway reduces clearance of an itaconate / CoA intermediate (not sure the name now, will look up later). That would ty up CoA longer extending needed CoA availability recovery time in the mitochondria.

On the other hand, this extra load on vitamine B12 / methylation pathways due to need for clearing itaconate metabolites would slow down break down excess (TLR2 and TLR4 triggering) glucosamine levels by slowing methylation to 1-methyl-galactose IF that were the needed pathway. Being low on ATP wouldn't help either.

=> So both hypothesises seem to be complementairy, not competing.

 

[dejurgen]

https://en.wikipedia.org/wiki/Glucuronidation:

"Glucuronidation is often involved in drug metabolism of substances such as drugs, pollutants, bilirubin, androgens, estrogens, mineralocorticoids, glucocorticoids, fatty acid derivatives, retinoids, and bile acids. These linkages involve glycosidic bonds.[1]"

=> So binding to glucuronide is a common way to make "waste", polutants or metabolites more soluble in water and easier to remove by urine and feaces. It removes many androgens and glucocorticoids (like anti inflammatory cortisol related molecules). Here we say glucoride removes the excess of something else.

=> But when glucoride itself is in excess, the other molecules can be scooped up "too early", before their "end of use time". So excess glucuronide has the potential to scoop up and remove still usefull androgens and glucocorticoids. According to the 1000 plasma metabolite study, tesoterone metabolites seem to be particularly suited to do that, more then female hormones (IF the test studied those, didn't check yet).

=================================================================================
Now an attempt at another ME/CFS mistery: often very strong *temporary* progress during pregnancy
=================================================================================

Pregnane-x-receptor controls hepatic glucuronidation during pregnancy and neonatal development in humanized UGT1 mice - PubMed

PXR is a key regulator of pregnancy induced glucuronidation capacity in addition to modulating the severity of neonatal jaundice.

pubmed.ncbi.nlm.nih.gov

Title "Pregnane-x-receptor controls hepatic glucuronidation during pregnancy and neonatal development in humanized UGT1 mice"

Saying "In humanized UDP glucuronosyltransferase-1 (hUGT1) mice that express the entire UGT1 locus, the maternal hepatic UGT1A genes are dramatically induced 12-14 days after conception."

In play English meaning IMO: pregnancy increases (parts of) the womens body to "add, glue" glucuronic acid to plenty of other molecules.

=> Whatever the purpose of that, that IMO has the potential to get rid of a lot extra glucuronic acid to "somehwere", wherever that is. That could / might include synthesizing hyaluronic acid anew for the womb and growing baby but I am not sure about that yet.

Still: https://pmc.ncbi.nlm.nih.gov/articles/PMC6120812/
Title "Cervical hyaluronan biology in pregnancy, parturition and preterm birth"

Saying "

ROLE OF HA IN THE CERVIX DURING PREGNANCY AND PARTURITION​

HA Synthesis​

The enzyme responsible for HA synthesis, hyaluronan synthase (Has), is encoded by three genes termed Has1, Has2, and Has3 [14, 15]. The expression of Has2 is critical in development as mice with a global targeted mutation in the Has 2 gene die on gestation day 10.5 due to cardiac defects [16]. In contrast mice lacking Has1 and Has 3 are viable with no essential role in development [17]. The development of a floxed Has2 allele provides a valuable tool for assessment of Has2’s role in the adult mouse [18]. Has1 and Has3 expression is low to negligible in the nonpregnant and pregnant cervix of women and mice [11]. In contrast, Has2 expression is induced at term in women and in mice on gestation day 15 with peak expression during cervical ripening on gestation day 18. Consistent with the expression of Has2, the HA content in the mouse cervix increases from 7.4 nmol/mg dry wt in nonpregnant to 24.6 nmol/mg dry wt on gestation day 18 [19]. Thus during term ripening on gestation day 18 the total GAG content more than doubles with HA comprising 71% of total GAGs as compared to nonpregnant in which HA comprises 51% of total GAGs."

=> So more hyaluronic acid production during pregnancy (potentially scooping up excess glucosmaine and gluuronic acid molecules quickely as that are the building blocks of hyaluronic acid.

=> Also of note: I recently found a paper that showed that female blood volume significantly rose during pregancy (already able to explain some of the variance in disease behavior) and it seemed percent wise a lot greater then the weight gain during pregnancy (resulting in more blood volume per kg of woman plus growing baby). Too tired to look that one up.

Now, it seems that increased blood volume might be a side effect of less hyperventialation to get CO2 out and acidity down as there is less need to tame the immune system IF pregnancy would reduce free floating hyaluronic acid plus glucuronide plus glucosamine fragments after each exertion.

=================================================================================
Also a weaker link with glucuronic acid and the female cycle
=================================================================================

The Use of Estrone-3-Glucuronide and Pregnanediol-3-Glucuronide Excretion Rates to Navigate the Continuum of Ovarian Activity - PMC

The patterns of a woman's normal ovarian activity can take many forms from childhood to menopause. These patterns lie on a continuum ranging from no ovarian activity to a fully fertile ovulatory cycle, but among the other defined patterns are cycles ...

pmc.ncbi.nlm.nih.gov

title "

The Use of Estrone-3-Glucuronide and Pregnanediol-3-Glucuronide Excretion Rates to Navigate the Continuum of Ovarian Activity"​

=> See figure1: some female hormones bound to glucuronic acid are excreted up to 10 fold during certain days of the female cycle, potentially getting rid of a significant amount of excess glucuronic acid. In women with ME/CFS, FM, connective tissue this opens the path to stronger fluctuations during the cycle then healthy women too as more glucuronic acid in the plasma *could* increase this process. But depending on the bottlenecks, it could go the other way around too. As a man I have no experience with ME/CFS plus cycle variation. Still, the increased removal of glucuronic acid bound to sterols during part of the cycle still seems to hold for all woman.


Note to self: NOW REST AND STICK TO IT!

 

[dejurgen]

I found another interesting link with low Dopamine levels and Serotonin metabolism (dr. Robert Phair's hypothesis we produce excessive seratonine but that isn't reported in metabolomic studies yet).

The UDP-glucuronosyltransferases of the blood-brain barrier: their role in drug metabolism and detoxication - PMC

UDP-glucuronosyltransferases (UGTs) form a multigenic family of membrane-bound enzymes expressed in various tissues, including brain. They catalyze the formation of β-D-glucuronides from structurally unrelated substances (drugs, other xenobiotics, ...

pmc.ncbi.nlm.nih.gov

"Both DA and 5HT and their respective metabolites can undergo conjugation with glucuronic acid or sulfonate mediated by UGTs and SULTs respectively, that occurs in both central nervous system and periphery."

"However, in rat CSF, DA glucuronide was found predominant over DA-sulfate and free DA, suggesting that glucuronidation was an important metabolic pathway for DA of central origin"

"The presence of intact glucuronide as the major DA conjugate was recently confirmed in rat and mouse brain microdialysates using liquid chromatography tandem mass spectrometry (LC-MS/MS; Uutela et al., 2009a). LC-MS/MS also detected 5-HT-glucuronides at concentration 2-times than HT itself (Uutela et al., 2009b). Altogether, the results indicated that in rat, neurotransmitters are glucuronidated whereas their phase I metabolites are sulfated"

=> In English: in some cases, brain (and other places) dopamine is found more in its glucuronidated form then as free dopamine itself and the same holds for 5-HT (alternative seratonin name).

=> Increase glucuronic acid a lot in ME/CFS as in this post subject / hypothesis and that metabolic study, and the balance of those metabolites should further shift away from dopamine and seratonin towards their glucuronidated form.

=> That could help explain the (likely) reduced dopamine levels in ME/CFS and the (likely) normal-ish seratonine levels despite dr. Robert Phair finding genetic computational indications it should be increased a lot.

Melatonin is a derivative of seratonin. And it too exist in glucronide form:

Associations between Melatonin, Neuroinflammation, and Brain Alterations in Depression - PMC

Pro-inflammatory systemic conditions that can cause neuroinflammation and subsequent alterations in brain regions involved in emotional regulation have been suggested as an underlying mechanism for the pathophysiology of major depressive disorder ...

pmc.ncbi.nlm.nih.gov

" Circulating melatonin is metabolized primarily in the liver and secondarily in the kidney. Melatonin is hydroxylated to 6-hydroxymelatonin, followed by sulfate conjugation to 6-hydroxymelatonin sulfate (90%) or glucuronide conjugation to 6-hydroxymelatonin glucuronide (10%), with approximately 5% of serum melatonin being excreted unmetabolized through urine."

glucuronidation may be a minor pathway under normal glucuronic acid levels, but with the observed (in the metabolomic study) increased glucuronic acid levels in ME/CFS, there is a *chance* this pathway becomes a whole lot more active in us. How much is hard to predict, those relationships do not need to be linear. But I do know I can be "too tired to sleep" when I crash, and sleep disorder is rather common in ME/CFS.

 

[dejurgen]

Further indications that "hyaluron fragmentation" could strongly stimulate the immune system:

Hyaluronic acid - Wikipedia

en.wikipedia.org

"Hyaluronic acid is also a component of the group A streptococcal extracellular capsule,[8]"

Link [8] checks out:
"The results obtained are consistent with the hypothesis that chain elongation of hyaluronic acid proceeds by alternate addition of monosaccharides from UDP-sugars by a membrane-bound synthesizing system fol-
lowed by release of completed hyaluronic acid chains"

=> In English: hyaluronic acid is part of larger molecules on the "skin" of common bacteria Streptococcus. Hence it makes sens that our (innate) immune system reacts quite strong to it.

 

[dejurgen]

Subject: Gut microbial diversity under influence of glucuronic acid in the bowels, part 1

The research in this paper designed ways to test the impact of glucoronic acid on the gut microbiome. The limited results to test the method that they published are enough to give us a glance at the potential relationship between increased glucuronic acid levels and reduced gut microbiome diversity:

Synthetic β-d-Glucuronides: Substrates for Exploring Glucuronide Degradation by Human Gut Bacteria - PMC

The human gut microbiota (HGM) is a complex ecosystem subtly dependent on the interplay between hundreds of bacterial species and numerous metabolites. Dietary phenols, whether ingested (e.g., plant-derived guaiacol, mequinol, or resveratrol) or ...

pmc.ncbi.nlm.nih.gov

Figure 4A shows the average decrease in growth of 9 different bacterial species when 1mM of glucoronic acid is added to the mix. The best performing species see "only" a 30% reduction in growth rate. The 3 worst performing species see a (hard to read) 97 to 98% reduction in growth. Put another way, the growth rate of the best performing species dropped to 70% of the speed without glucuronic acid while the growth rate of the 3 worst performing species dropped to a whooping 2 to 3%!

=> Under those laboratory conditions, the worst performing species grow roughly 25 to 30 times slower then the best performing species. Since bacterial / microbial communities are rather competitive, the very slow growers would have a good chance to be near erradicated if that translated to in vivo (in our gut) conditions if we had significantly increased glucoronic acid in the gut. That fits with decreased gut microbial diversity as seen in ME/CFS microbiome research:

Fecal metagenomic profiles in subgroups of patients with myalgic encephalomyelitis/chronic fatigue syndrome - Microbiome

Background Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is characterized by unexplained persistent fatigue, commonly accompanied by cognitive dysfunction, sleeping disturbances, orthostatic intolerance, fever, lymphadenopathy, and irritable bowel syndrome (IBS). The extent to...

microbiomejournal.biomedcentral.com

 

[dejurgen]

Subject: Gut microbial diversity under influence of glucuronic acid in the bowels, part 2

The research highlighted another part of altered gut microbiome in:

Synthetic β-d-Glucuronides: Substrates for Exploring Glucuronide Degradation by Human Gut Bacteria - PMC

The human gut microbiota (HGM) is a complex ecosystem subtly dependent on the interplay between hundreds of bacterial species and numerous metabolites. Dietary phenols, whether ingested (e.g., plant-derived guaiacol, mequinol, or resveratrol) or ...

pmc.ncbi.nlm.nih.gov

The paper shows that the reaction of bacteria to many chemicals is rather different to the "free form" versus the "glucuronidated form of it". One form can considerably decrease bacterial growth while the other can considerably increase growth.

We therefore look at Figure 3A and 3B. The Figure needs some explanation to interprete. 2 bacterias, species B. Caccae in Figure 3A and species B. thetaiotaomicron in Figure 3B are subjected to 3 forms of non-glucuronide methoxyphenyl and 3 forms of β d-glucuronide forms of methoxyphenyl.

For example species B. Caccae grows 27% slower when subjected to (the non glucuronide form of) 2-methoxyphenyl and 28% faster when subjected to the (glucuronide form) 2-methoxyphenyl β d-glucuronide, as depicted in Figure 3A.

Now this shows that bacteria B) grows better on all three glucuronidated forms of the added chemicals but worse on the non-glucuronidated form. For bacteria A) the same holds for 2 out of 3 tested variants (2- and 4- form) of methoxyphenyl.

The test chemical is artificial, but a surprising long list of (often considered healthy anti-oxidants) can exist in both glucuronidated as non-glucuronidated form:

" Dietary phenols, whether ingested (e.g., plant-derived guaiacol, mequinol, or resveratrol) or products of bacterial fermentation (e.g., p-cresol), have been attributed with influencing bacterial growth and host health."

Many of those are anti-oxidants (for both plants and us when we consume them) but many of these chemicals also double as anti-fungal or anti-bacterial defense chemicals to the plant. In humans, glucuronidation of a chemical is one of multiple steps in removing (sometimes toxic) waste from the body. Often, but not always, the glucuronidated version of the chemical is less active / less toxic then the free form of the chemical. We see roughly the same above: the non-glucurodinated (free) form of the tested chemicals in Figure 3 lead most often to slower bacterial growth then the glucuronidated form (or "potentially desactivated form").

Still: an important conclusion here is that glucurodinated biochemicals versus non-glucurodinated (free form) chemicals alters microbial growth rates and with it the balance between gut microbiome species and amount of total gut microbiome species.

Why this is important: if we would have an abundance of glucuronic acid in the gut during rest and / or crashes then it could help further explain the altered microbiome diversity seen in ME/CFS. Since the studies in the first comment of this thread showed increased glucuronide and related chemicals in blood plasma AND urine, it would be reasonable to assume it is increased / excreted in the bowel too.

 

[dejurgen]

Subject: glucuronic acid availability in the gut and food (and drug) absorption.

The body uses glucuronidation of many (often "oil like", hard to disolve in water) chemicals to make them better soluble in water and then remove them via the liver into urine and faeces. It also in part works the other way around: chemicals that are in the glucuronide form often are poorly absorbed from the gut. That makes sense, as otherwise the body would keep absorbing it's own waste it dumped in the gut.

If you look at the above comment, you might already spot a problem: resveratrol, often considered a healthy chemical with plenty of good properties (although it can be toxic under specific circumstances too), also can exist in both free form and glucuronide form in the gut. And there is rather good chance that bioavailability of the later is very poor. This is the subject of:

Intestinal glucuronidation metabolism may have a greater impact on oral bioavailability than hepatic glucuronidation metabolism in humans: a study with raloxifene, substrate for UGT1A1, 1A8, 1A9, and 1A10 - PubMed

The kinetic impact of intestinal glucuronidation metabolism on oral bioavailability (F) was assessed using reported human data of raloxifene, of which oral bioavailability was only 2%. Kinetic analysis showed that presystemic intestinal availability (Fpg) was 5.4%, whereas fraction absorbed (Ff)...

pubmed.ncbi.nlm.nih.gov

Saying "Therefore, it is also suggested that intestinal glucuronidation catalyzed by UGTs, particularly UGT1A8 and UGT1A10, may play important roles in the first-pass metabolism, causing low oral bioavailability."

For example for a drug (more commercial interest to do extensive studies on absorption then on unpatented nutrients), so better data is available:

https://www.sciencedirect.com/science/article/abs/pii/S0378517320307158

"the absorbed drug undergoes pre-systemic glucuronide conjugation limiting its oral bioavailability (Deguchi et al., 2011). Across different animal species, the oral bioavailability of RLX varies from 0 (dogs) to 39% (rats) (Mizuma, 2009). The low solubility of RLX coupled with gut wall glucuronide conjugation, significantly contributes to the poor oral bioavailability across different animal species (Mizuma, 2009, Trdan Lusin et al., 2012)."

=> It is a recurring subject (with hard to find details on it): at the interface of the gut, chemicals can undergo a transformation from "free form" to "glucuronide form" and with it often have much lower bioavalability (passing from gut to blood). Also bile (in one of the studies cited in this thread) can get glucuronidated and excreted rather then mostly reabsorbed leading to diarrea.

=> Wether that glucuronide comes from inside the body (blood and intracellular fluids) or from the gut (through bacteria splitting glucurodinated chemicals in the free form of it plus free glucuronide) is unclear, but information points to the first. Regardless, glucuronic acid has been found elevated in ME/CFS plasma and in this hypothesis quite like also in the gut so there should be enough glucuronic acid available to increased "gut wall glucuronide conjugation".

In other words: a rather increased availability of glucuronic acid in ME/CFS has *a good chance* to lead to transform a lot of free form nutrients to its glucuronide form *on the outside side of the bowel*, leading in most cases to drastic lower bioavailability.

I had found a list of chemicals that exist both in free form and glucuronic acid and it was extensive (but can't find it back now). It included plenty of strong nutritional anti-oxidants and things like vitamin E (tocopherol). Even omega-3 and omega-6 and monostaurated fatty acids can exist in glucurodinated form.

In summary: excess glucuronide availability can both account for decreased gut microbiome diversity (part 1 and 2 above this) and poor to rather poor absorption of a long list of anti-oxidants and anti-inflammatory nutrients. The already low amount of these (class of) absorbed nutrients may in addition be quickly glucurodinated in the plasma and with it potentially less active and quickly excreted again. Both are in line with what is observed in ME/CFS.

 

[dejurgen]

The idea that the gut would transform many important nutrients to a form it can only poorly absorb may seem plain wrong in a condition as ME/CFS, where we *might* (no certainty, with ME/CFS it can go all directions) need more not less of these normally protective nutrients.

Yet, many toxins are also prone to glucurodination. That may be a main purpose when the immune system gets in a state of strong defense: to keep out all potential threats as well as possible.

The brain-blood-barrier (BBB) seems to take a simmilar approach, as well as some blood vessels:

Frontiers | The UDP-glucuronosyltransferases of the blood-brain barrier: their role in drug metabolism and detoxication

UDP-glucuronosyltransferases (UGTs) form a multigenic family of membrane-bound enzymes expressed in various tissues, including brain. They catalyze the forma...

www.frontiersin.org

saying "In brain, UGTs actively participate to the overall protection of the tissue against the intrusion of potentially harmful lipophilic substances that are metabolized as hydrophilic glucuronides. These metabolites are generally inactive, except for important pharmacologically glucuronides such as morphine-6-glucuronide. UGTs are mainly expressed in endothelial cells and astrocytes of the blood brain barrier (BBB). They are also associated to brain interfaces devoid of BBB, such as circumventricular organ, pineal gland, pituitary gland and neuro-olfactory tissues."

In more common English: at the BBB, a class of UGT enzymes actively transform chemicals to their glucuronide form to try and keep out potentially harmfull (fat based, lipophyillic) substances.

That also may mean: if glucuronide is increased in ME/CFS plasma, then many lipophyllic components *that are normally usefull and needed substances to the brain like maybe vitamin E and resveratrol?* are allowed to get into the brain at reduced speed (compared to healthy controls), much like what happens to many nutrients trying to enter the blood from the gut.

If so, the problem would compound as the rate of transfer from these nutrients would not only decrease from the blood to the brain. The starting amount of those nutrients in the blood (in the body minus the brain) would already be reduced by the same mechanism in the gut. That would pottentially severally deprive the brain from some nutrients. On the plus side, the double whammy to usefull nutrients would also happen to harmfull substances. Those would see two consecutive bottlenecks as well.

Many people believe in ME/CFS the BBB is compromised and more harmfull substances get in the brain, and therefore our brain has a hard time. Maybe the mirror hypothesis is that in ME/CFS the BBB is extra selective and reduces the supply of a selection of much needed nutrients to the brain, and therefore our brain has a hard time. Both may even be possible at the same time, depending on the type of substance.

 

[dejurgen]

I have been digging some deeper into this.

* Glucosamine will not be the source of Methyl-α-D-galactose. Deanimation of D-glucosamine will yield fructose 6-phosphate by the enzyme Glucose 6-Phosphate Deanimase:
D-glucosamine 6-phosphate + H2O ⇌ D-fructose 6-phosphate + NH3
* Where it comes from is rather hard to trace. There seem to be very few functional routes to create that chemical.

* There are other human produced polysaccharides that are prone to HOCl and can produce plenty of glucuronic acid. One of them is heparin, a chemical involved in (reducing) blood clotting and is secreted by activated mast cells. Both are prone to fragmentation, multiplying potential for quick TLR2/TLR4 activation when HOCl producing immune cells / enzymes fire up their activity.

* I before disregarded heparin as it is often highly sulfated, but I found that the body has sufficient means to remove the sulphur groups in order for it to not hamper the conversion to glucuronic acid.

* While there is clear potential for the glucuronic acid to come from an altered gut microbiome, I feel the quick escalation of symptoms when severe ME/CFS patients overdo it align well with quick hyaluronic acid or another relevant endogenous polyssacharide fragmentation under influence of quickly rising oxidative stress.

That's it for now. I'll go back and work in silence trying to sort out more things.

 

[Rockt]

dejurgen, any progress with this? Have you thought of any drugs or supplements or foods that could help with this?

 

[dejurgen]

Hi Rockt,

I've been picking this back up a few times but unfortunately it seems to leave pretty few margin for treatment options. The problem is that glucuronic acid has both protective properties and problematic properties. That seems to be the recurring storry with (my understanding of ME/CFS): many things that cause typical ME/CFS symptoms and form part of the vicious circle keeping us sick are also things that serve a role in stopping or reducing the problems another mechanism causes. Glucuronic acid is a good antioxidant and vital chemical for detoxifying a wide array of toxins on one hand and can exacerbate inflammatory symptoms and pain on the other hand.

Therefor there seems to be no simple conclusion possible. Each persons body seems to optimize this as well as possible. Trying to finetune this both at baseline (constant dosing) as during acute circumstances (near PEM) seems to be highly dependent of individual body chemistry. It's not that our bodies are too conservative detoxifying nor that they are too lose with allowing inflammation. The problem is more that we need more detoxifying then most people (which should shift glucuronic acid up) and are more prone to inflammation then most people (which should shift glucuronic acid down). So we in essence are (in this understanding) stuck between a rock and a hammer.

Still I have a few thoughts that may help:
* It seems that several anti-oxidants / anti-inflammatory natural products that have poor bio-availability (think of quercetin and curcumin...) may not entirely have poor bio-availability. They seem to enter the mouth as the pure product and leave the body in a glucuronidated form. Conventionally, that is seen as poor bio-availability as the product tends to show very low concentration in the blood. The often chosen solution is to go for special (and expensive) high-uptake versions and / or really high concentrations.
I think this may be a wrong view. The product seems to be taken up rather quickly but even excreted even faster in a glucuronidated form. In the bloodstream it then effectively modified / reduced glucuronic acid and that is a biomedical action.
=> Conventionally dosing may be ironically too high for us to help, since there is only a small margin in which we can *try* (difficult!) to optimize it's concentration. Trying to super-dose so that a product like curcumin gets elevated in the blood may too aggressively remove glucuronic acid and hamper our detoxing ability when we try to reduce inflammation by it. We then sort of trade one set of symptoms for another set of symptoms and just shift them rather then improve. Going with that: I found a lot of evidence that some forms of curcumin are taken up better then others but rather few research proving that those forms actually work better then the simple product itself.

* In line with that, microdosing a few products (like curcumin plus quercetin plus...) able to take away glucuronic acid may work better then an equivallent (total weight / activity of those separate products) dose of a single one of those.

* My understanding may help to explain why some people report taking a modest dose of curcumin some time ahead of an expected exertion helps reduce PEM (IF I remember those claims well, hard to find them back). Then they can arrive at the time that excess inflammation triggers excess glucuronic acid that triggers even more inflammation, and dampen a (possible significant) signal in this inflammatory upswing. Still I believe timing is hard to achieve and dosing best to be rather low. More importantly: it should NEVER be used to excuse overexertion e.g. seen as an excuse to push even deeper in the red. Pacing is and remains king.

* There are differences in glucuronic acid breakdown speed between males and females, but those are less then I anticipated. The common lab animal called mouse is the biggest excemption to this, coloring research reports. However the inflammatory upswing (which in this view drives immune cell made HOCl to damage connective tissue and raise glucuronic acid) is bigger in females. Now I believe that is a main difference in ME/CFS susceptibility. A slightly (as in a healthy and rounded diet, nothing aggressive) less acidic diet (compared to standard Western diet) therefor could help, as that should reduce HOCl production by the immune system. But that is nothing new.