torsdag den 5. marts 2020

ME - a failure of inducing exercise tolerance?

ME hypothesis from Karolinska Institutet and Karolinska University Hospital in Sweden (1):

"ME - a failure of inducing disease tolerance upon chronic immune activation"

My question:
Is ME also a failure of inducing exercise tolerance?

At cellular level disease and inflammation result in increased reactive oxygen species (ROS) production. Stress-response pathways are countermeasures to ROS. Exercise also leads to increased ROS levels. The antioxidant enzyme superoxide dismutase 2 (SOD2) is one the primary mechanisms against ROS generated during exercise.

Quote from a review "Impact of oxidative stress on exercising skeletal muscle" (2):
"It is well established that muscle contractions during exercise lead to elevated levels of reactive oxygen species (ROS) in skeletal muscle. These highly reactive molecules have many deleterious effects, such as a reduction of force generation and increased muscle atrophy. Since the discovery of exercise-induced oxidative stress several decades ago, evidence has accumulated that ROS produced during exercise also have positive effects by influencing cellular processes that lead to increased expression of antioxidants. These molecules are particularly elevated in regularly exercising muscle to prevent the negative effects of ROS by neutralizing the free radicals. In addition, ROS also seem to be involved in the exercise-induced adaptation of the muscle phenotype.

Chronic oxidative stress is associated with an increase in protein loss and muscle atrophy. High ROS levels cause a sustained activation of NF-κB and of FoxO which then activate two muscle-specific E3 ubiquitin ligases, atrogin-1 or muscle atrophy F-box (MAFbx) and muscle RING (Really Interesting New Gene)-finger protein 1 (MuRF-1) [52]. MAFbx and MuRF-1 then degrade various proteins, such as titin, nebulin, troponin, myosin-binding protein C, myosin light chains 1 and 2 and myosin heavy chain [53,54]. Recently, it was demonstrated that excessive oxidative stress also enhances the transcription factor C/EBP homology protein (CHOP). This transcription factor also enhances expression of MuRF1, which again results in increased protein degradation [35]."

It seems like ME patients have increased muscle protein degradation:

Increased serum and urine 3-methylhistidine in ME patients

Increased plasma N,N,N-trimethyl-L-alanyl-L-proline betaine in ME patients

Proline, P5C and 4-hydroxyglutamate in ME

And do remember the transcription profile analysis of skeletal muscle from ME patients (3), quote:
"In an effort to establish which pathways might be involved in the onset and development of muscle symptoms, we used global transcriptome analysis to identify genes that were differentially expressed in the vastus lateralis muscle of female and male CFS patients. We found that the expression of genes that play key roles in mitochondrial function and oxidative balance, including superoxide dismutase 2, were altered, as were genes involved in energy production, muscular trophism and fiber phenotype determination. Importantly, the expression of a gene encoding a component of the nicotinic cholinergic receptor binding site was reduced, suggesting impaired neuromuscular transmission. We argue that these major biological processes could be involved in and/or responsible for the muscle symptoms of CFS."

Are the inflammatory reponse to disease and the adaptive response to exercise dysregulated in ME through the same pathways?


1) Lucie S.T. Rodriguez, Christian Pou, Tadepally Lakshmikanth, Jingdian Zhang, Constantin Habimana Mugabo, Jun Wang, Jaromir Mikes, Axel Olin, Yang Chen, Joanna Rorbach, Jan-Erik Juto, Tie Qiang Li, Per Julin, Petter Brodin: Achieving symptom relief in patients with Myalgic encephalomyelitis by targeting the neuro-immune interface and inducing disease tolerance

2) Peter Steinbacher, Peter Eckl:
Impact of Oxidative Stress on Exercising Skeletal Muscle

tirsdag den 3. marts 2020

Det inflammatoriske respons og induktion af sygdomstolerance er dysreguleret hos ME patienter

Forskere fra Karolinska Instituttet og Karolinska Universitetshospital har beskrevet en ME hypotese (1):

"ME - a failure of inducing disease tolerance upon chronic immune activation"

Sygdomstolerance er en overordnet betegnelse for en række stress-respons stiveje. Disse skal sørge for at begrænse skade fra patogene mikroorganismer og fra kroppens inflammationsproces.

Vagusnerve og hjernestamme regulerer systemisk inflammation ved at skrue op eller ned for den inflammatoriske refleks. Nerver der fører fra kroppen (afferent vagus nerve endings) til hjernestamme sender besked om immunstatus i kroppen. Nerverne kan f.eks. sende besked om aktivitet fra patogene mikroorganismer i tarmen. Nerver der fører fra hjernestamme (efferente) til kroppen  sender signaler via acetylcholin om at dæmpe inflammationen. 

Det er kendt viden, at påvirkning af vagusnerven kan dæmpe inflammatoriske tilstande.

Forskerne fra Karolinska afprøvede Intranasal Mekanisk Stimulation (INMEST) på en gruppe ME patienter. INMEST udstyret består af et tyndt plasticrør, som placeres i næsen. Udstyret vibrerer og danner en turbulent luftstrøm. Dette inducerer en nervereflex, som påvirker vagusnerven. Behandlingen dæmpede nogle ME symptomer (men ikke fatigue), og blodprøver fra patienterne viste normalisering af inflammatoriske tilstande (1).

En analyse af sygdomstoleranceprogrammer viste, at INMEST behandling opregulerede disse programmer.

Forskerene påpegede, at årsagen til den manglende induktion af tolerance hos ME patienter skal klarlægges. Samtidig henviser de til forskningen i IDO2 enzymet, som netop er involveret i regulering af sygdomstolerance.

Mere viden om emnet kan findes her:

Neural Reflexes in Inflammation and Immunity

The Vagus Nerve and the Inflammatory Reflex--Linking Immunity and Metabolism

Er der behandlingsmuligheder i lægemidler, der øger aktivitet i acetylcholin-stiveje?:

Central and peripheral anti-inflammatory effects of acetylcholinesterase inhibitors

Aryl Hydrocarbon Receptor Control of a Disease Tolerance Defence Pathway

Relevante blogindlæg:

Indånding af skimmel er noget, der kan gøre en ME/MCS patient ganske syg. IDO er med til at inducere tolerance i næsens slimhinder, og mutationer i IDO-generne har betydning for kroppens reaktion på skimmel infektion (AHR = Arylhydrocarbon receptor, MCS = multiple chemical sensitivity): 

IDO-ME hypotesen er forenelig med AHR-MCS hypotesen

Tryptofan metabolitten kynureninsyre har immunmodulerende egenskaber


1) Lucie S.T. Rodriguez, Christian Pou, Tadepally Lakshmikanth, Jingdian Zhang, Constantin Habimana Mugabo, Jun Wang, Jaromir Mikes, Axel Olin, Yang Chen, Joanna Rorbach, Jan-Erik Juto, Tie Qiang Li, Per Julin, Petter Brodin: Achieving symptom relief in patients with Myalgic encephalomyelitis by targeting the neuro-immune interface and inducing disease tolerance

mandag den 2. marts 2020

Increased serum and urine 3-methylhistidine in ME patients

3-metylhistidine is a breakdown product of muscle contractile proteins. Serum or urine 3-methylhistidine is used as a biomarker of muscle protein degradation (1).

Fluge et al found increased serum 3-metylhistidine in male ME patients (2).

McGregor et al found increased urine 3-metylhistidine in post-exertional malaise (PEM) ME patients (1).

Quote from McGregor et al (1):
"The findings that the PEM is associated with a loss of metabolites, reduction in acetylation, deregulation of purine metabolism, increased contractile protein breakdown and bacteremia associated with exercise suggest that treatments such as graded exercise may be more detrimental than beneficial as claimed in some studies [39,40]. Until such time as these biological changes can be further investigated, the use of graded exercise as a therapy for those with severe forms of ME/CFS should be considered potentially harmful. In support of this, the use of graded exercise therapy has caused significant protest by ME/CFS sufferers as they see it as harmful [41,42]."

Further reading about possible breakdown of skeletal muscles in ME patients :

Proline, P5C and 4-hydroxyglutamate in ME

Increased plasma N,N,N-trimethyl-L-alanyl-L-proline betaine in ME patients

1) McGregor et al: Post-Exertional Malaise Is Associated with Hypermetabolism, Hypoacetylation and Purine Metabolism Deregulation in ME/CFS Cases Diagnostics (Basel). 2019 Jul 4;9(3). pii: E70. doi: 10.3390/diagnostics9030070.

2) Fluge et al: Metabolic profiling indicates impaired pyruvate dehydrogenase function in myalgic encephalopathy / chronic fatigue syndrome. JCI Insight. 2016; 1(21):e89376. Doi 10.1172/jci.insight.89276

onsdag den 19. februar 2020

Increased plasma N,N,N-trimethyl-L-alanyl-L-proline betaine in ME patients

N,N,N-trimethyl-L-alanyl-L-proline betaine (TMAP) is a plasma biomarker of reduced kidney function (1).

Quote from ref 1:
"TMAP was the most consistently cleared metabolite by all hemodialysis modalities in our untargeted metabolomics analysis. Although the biological origin of TMAP has not been identified, we suggest that TMAP may be produced from degradation of myosin light chain (MYL) proteins. N,N,N-trimethylalanine is mainly found in myosin light chain (MYL) proteins and in each of the four MYL isoforms (MYL1, MYL2, MYL3, and MYL4), the c-terminus of N,N,N-trimethylalanine forms a peptide bond with proline (26). Therefore, MYL protein degradation may be responsible for the release of TMAP. Further study is necessary to determine the biological origin and potential physiological effects of TMAP."

Myosin light chains are components of macromcular myosin complexes. Fx. myosin II is the myosin type responsible for producing muscle contractions in muscle cells. Myosin II contains two heavy chains and four ligtht chains. ( Wikipedia. Myosin )

Plasma TMAP was increased in ME patients in Germain et al's metabolomic study (2020) (2).

As far as I know, ME patients have normal kidney function, so why is TMAP increased? Is the turnover of myosin light chains increased? And/or do the increased TMAP level reflect the breakdown of skeletal muscles?

Further reading about possible breakdown of skeletal muscles in ME patients :

Proline, P5C and 4-hydroxyglutamate in ME

1) Velenosi, T.J., Thomson, B.K.A., Tonial, N.C. et al. Untargeted metabolomics reveals N, N, N-trimethyl-L-alanyl-L-proline betaine (TMAP) as a novel biomarker of kidney function. Sci Rep 9, 6831 (2019). PMID: 31048706  PMCID: PMC6497643

2Arnaud Germain , Dinesh K Barupal , Susan M Levine , Maureen R HansonComprehensive Circulatory Metabolomics in ME/CFS Reveals Disrupted Metabolism of Acyl Lipids and Steroids. Metabolites 2020, 10(1), 4;

onsdag den 5. februar 2020

Proline, P5C and 4-hydroxyglutamate in ME

What do

  • Pre-eclampsia
  • The inborn error of metabolism: Primary Hyperoxaluria Type 3
  • Myalgic encephalomyelitis (ME)

have in common?

Increased levels of 4-hydroxyglutamate (1, 2, 3).

Germain et al's (2020) new metabolomic study found increased level of plasma 4-hydroxyglutamate  in ME patients compared to controls (3).

From figure S1 in reference 3. 4-hydroxyglutamate. Box plot distribution of logged values from table 2 in reference 3. Controls are shown in red and ME patients in blue. The yellow diamond represents the mean.

Proline and its metabolite hydroxyproline (OH-proline) are amino acids. They constitute one-third of the amino acids in collagen proteins.

High levels of 4-hydroxyglutamate could result from increased collagen turnover and the release of proline and 4-hydroxyproline. The latter is metabolized to 4-hydroxyglutamate. Proline is re-used and 4-hydroxyproline is broken down and excreted in this pathway (4):

Figure 1 from Riedel et al, reference 4: Metabolism of 4-hydroxyproline and glyoxylate.
Four mitochondrial enzymes are responsible for 4-hydroxproline (4-Hyp) breakdown: hydroxyproline oxidase (HPOX), Δ1-pyrroline-5-carboxylate dehydrogenase (1P5CDH), aspartate aminotransferase (AspAT), and 4-hydroxy-2-oxoglutarate aldolase (HOGA). The terminal HOGA reaction cleaves 4-hydroxy-2-oxoglutarate (HOG) into pyruvate and glyoxylate. Glyoxylate is metabolized either to glycolate by glyoxylate reductase (GR) in the mitochondria and cytoplasm or to glycine by peroxisomal alanine-glyoxylate aminotransferase (AGT). AGT and GR are mutated within primary hyperoxaluria (type 1 and 2, respectively) patients resulting in the buildup of glyoxylate and its conversion by lactate dehydrogenase (LDH) to oxalate, a key component of kidney stones.

Naviaux et al showed increased plasma level of hydroxyproline in female ME patients (5).

Primary hyperoxaluria type 3 with increased urine 4-hydroxyglutamate is caused by mutations in the HOGA1 gene (4, 6).

Increasd levels of 4-hydroxyglutamate could also result from decreased activity of glutamic-oxaloacetic transaminase 2 (GOT2 = AspAT in figure 1 from ref 4) (1).

Schutzer et al showed decreased level of GOT2 precursor in cerebrospinal fluid from ME patients. Number of unique peptides in cerebrospinal fluid (table S1 in ref. 7): 
1) Controls: 6
2) ME patients: 1
3) Post treatment Lyme patients: 8

Why is 4-hydroxyglutamate increased in ME?

Is the proline-P5C cycle dysregulated in ME?

Naviaux et al showed increased plasma level of 1-pyrroline-5-carboxylic acid  (P5C) in ME patients (5).

A unique aspect of proline metabolism is the cycling of proline and P5C to maintain redox homeostasis between the cytosol and mitochondria. Proline biosynthesis, catabolism, and cycling, known as "the proline-P5C cycle" have been implicated as metabolic pathways selectively altered in cancer cells providing ATP, macromolecules, and redox cofactors (8).

The proline metabolism plays an important role in metabolic reprogramming, not only in cancer but also in related fields such as aging, senescence, and development (9).

The proline-P5C cycle: 

Figure 3 from reference 9. Hypothesis for proline cycle revised.
The cycle has been revised according to locations of the enzymes. The colored areas are for emphasis and do not represent specific locations. The dotted arrows represent putative shuttle systems, for example, malate/aspartate shuttle. PYCR1/2/L, pyrroline-5-carboxylate reductase 1/2/L.

Quote from reference 9: 
"The enzyme that oxidizes proline to P5C is tightly bound to mitochondrial inner membranes (30, 37, 38) and is linked to site II of the mitochondrial electron transport chain (30, 61) with a flavine adenine dinucleotide at the active site, which transfers electrons from proline to coenzyme Q (30, 95); at site III, proline-derived electrons have two dispositions. They can be transferred to cytochrome c, which is oxidized at complex IV with electrons transferred to O2 to form H2O. On the contrary, proline-derived electrons can directly reduce dissolved oxygen at complex III to form superoxide (23, 30). Since complex III has access to both the matrix space and the intermembrane space, ROS can evolve in the mitochondrial matrix or in the intermembrane space to be transferred into the cytosol as a putative redox signal. "

Is the collagen being broken down in ME patients to provide electrons for ATP synthesis?

If so, is AMPK involved in the process? And when/if AMPK "gives up", do ME cells go into senescence?

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Figure 2 from reference 9. PRODH/POX-mediated signaling. 
AMPK, AMP-activated protein kinase; ETC, electron transport chain; MYC, myelocytomatosis oncogene cellular homologue; PPARγ, peroxisome proliferator-activated receptor gamma. PRODH/POX, proline dehydrogenase/proline oxidase; ROS, reactive oxygen species.

A concern for a dysregulated proline-P5C cycle is the potential for cells to accumulate P5C, which was recently listed among the top 30 damage-prone endogenous metabolites. (8, 10).


1) Sovio et al: 4-Hydroxyglutamate Is a Novel Predictor of Pre-Eclampsia.
PMID: 31098639 DOI: 10.1093/ije/dyz098

2) Pitt et al: 4-hydroxyglutamate Is a Biomarker for Primary Hyperoxaluria Type 3
PMID: 24563386 PMCID: PMC4270872 DOI: 10.1007/8904_2013_291

3) Arnaud Germain , Dinesh K Barupal , Susan M Levine , Maureen R Hanson:
Comprehensive Circulatory Metabolomics in ME/CFS Reveals Disrupted Metabolism of Acyl Lipids and Steroids. Metabolites 2020, 10(1), 4;

4) Travis J Riedel , Lynnette C Johnson, John Knight, Roy R Hantgan, Ross P Holmes, W Todd Lowther: Structural and Biochemical Studies of Human 4-hydroxy-2-oxoglutarate Aldolase: Implications for Hydroxyproline Metabolism in Primary Hyperoxaluria.
Plos One

5) Naviaux RK, Naviaux JC, Li K, Bright AT, Alaynick WA, Wang L, Baxter A, Nathan N et al (2016) Metabolic features of chronic fatigue syndrome. Proc Natl Acad Sci U S A 113:E5472–E5480.

6) Greed, L., Willis, F., Johnstone, L. et al. Metabolite diagnosis of primary hyperoxaluria type 3. Pediatr Nephrol 33, 1443–1446 (2018).

7) Schutzer et al: Distinct Cerebrospinal Fluid Proteomes Differentiate Post- Treatment Lyme Disease from Chronic Fatigue Syndrome. PLOS One February 2011, volume 6, Issue

8) John J Tanner, Sarah-Maria Fendt , Donald F Becker , John J Tanner, Sarah-Maria Fendt , Donald F Becker: The Proline Cycle As a Potential Cancer Therapy Target

9) Phang: Proline Metabolism in Cell Regulation and Cancer Biology: Recent Advances and Hypotheses. Antioxid Redox Signal, 30 (4), 635-649 2019 Feb 1

10) Claudia Lerma-Ortiz et al: Nothing of Chemistry Disappears in Biology': The Top 30 Damage-Prone Endogenous Metabolites.
PMID: 27284066 DOI: 10.1042/BST20160073 Biochem Soc Trans (2016) 44 (3): 961–971.

fredag den 17. januar 2020

Naltrexone til behandling af ME

NK (Natural Killer) celler er en del af immunforsvaret. Det er gentagne gange påvist, at NK celler ikke fungerer optimalt hos ME patienter (1).

NK celler reguleres af en lang række celle signaler, - herunder calcium ion signalering. Ionkanalen TRPM3 bidrager væstentligt til calcium ion signalering i NK celler. 

Der er påvist signifikant reduktion af TRPM3 ekspression på overfladen af NK celler fra ME patienter (1).

Den G-protein-koblede receptor mu-opoid receptor (μOR) interagerer med TRPM3. Når μOR stimuleres inhiberes TRPM3 (1).

μOR kan hæmmes af lægemidlet Naltrexone, som er et lægemiddel målrettet til opioid-afhængige mennesker (2). Naltrexone i lav dosis anvendes også off-label til at modulere immunforsvaret i en række forskellige sygdomme.

Et forsøg med NK celler isoleret fra ME patienter viste at ved tilsætning af Naltrexone til NK cellerne, blev TRPM3 aktiviteten normaliseret (1).

Spørgsmålet er om Naltrexone kan være en behandlingsmulighed til ME? 

Læs også:
Low-dose naltrexone as a treatment for chronic fatigue syndrome

Finally Found – A Natural Killer Cell Enhancer for ME/CFS?


1) Helene Cabanas, Katsuhiko Muraki, Donald Staines1 and Sonya Marshall-Gradisnik: Naltrexone Restores Impaired Transient Receptor Potential Melastatin 3 Ion Channel Function in Natural Killer Cells From Myalgic Encephalomyelitis/Chronic Fatigue Syndrome Patients. Front. Immunol., 31 October 2019 |

2) Naltrexone

torsdag den 2. januar 2020

Trådløs teknologi påvirker mitokondrierne, når cellerne er stressede

Forskere fra et universitet i Schweiz har undersøgt, hvordan nerveceller påvirkes af radiofrekvente elektromagnetiske felter (RF-EMF). Forskerne udsatte en cellekultur af nerveceller for 935 MHz, 4 W/kg i 24 timer. Forsøget viste ikke påvirkning af cellerne, når næring og metabolisme var under normale forhold. Men når glucosen blev fjernet og cellerne blev stressede, registrerede man forringet mitokondrie funktion ved den følgende maximale respiration (1):

"These findings indicate that RF-EMF might lead to an impairment of mitochondrial function that is only manifest at maximal respiration and additional stressors such as glucose deprivation."

I et andet studie af RF-EMF udsætter man immunceller for 1,8 GHz og 200 V/m i 20 timer. Forsøget viste øget mitokondriel respiration, som var relateret til mitokondrie complex V aktivitet (2). Complex V danner energi-molekylerne ATP og kaldes derfor også for ATP syntase.

En del patienter med Myalgisk Encephalomyelitis (ME) udvikler elektromagnetisk hypersensitivitet (EHS). Man kan således formode, at ME sygdomsmekanismen er relateret til en RF-EMF følsom celleproces.

En undersøgelse af en lymfoblast cellekultur fra ME patienter viste (3): 

  • det stress-registrerende protein TORC1 var opreguleret
  • mitokondrie complex V fungerede ineffektivt
  • den mitokondrielle respiratoriske kapacitet var opreguleret (sandsynligvis for at kompensere for complex V ineffektivitet)

Cellestress, øget mitokondriel respiration og complex V påvirkning er således fællesnævnere for RF-EMF påvirkning og for ME.

Læs også:

Complex V is down in ME - does it also explain Electromagnetic Hypersensitivity?

Are rises in Electro-Magnetic Field in the human environment, interacting with multiple environmental pollutions, the tripping point for increases in neurological deaths in the Western World?

1) Niederhäusern et al: Effects of radiofrequency electromagnetic field exposure on neuronal differentiation and mitochondrial function in SH-SY5Y cells Toxicol In Vitro. 2019 Dec;61:104609. doi: 10.1016/j.tiv.2019.104609. Epub 2019 Jul 24.

2) Lassaivia et al: Exposure to 1.8 GHz electromagnetic fields affects morphology, DNA-related Raman spectra and mitochondrial functions in human lympho-monocytes. PLOS ONE. February 20, 2018.

3) Missailidis, D.; Annesley, S.; Allan, C.; Sanislav, O.; Lidbury, B.; Lewis, D.; Fisher, P. An Isolated Complex V Inefficiency and Dysregulated Mitochondrial Function in Immortalized Lymphocytes from ME/CFS Patients. Preprints 2019, 2019090043 (doi: 10.20944/preprints201909.0043.v1).