Augmentation of Anaerobic Pentose Phosphate Pathway Dysregulates Tetrahydrobiopterin Metabolism in Myalgic Encephalomyelitis/ Chronic Fatigue Syndrome (ME/CFS) Patients with Orthostatic Intolerance: A Pilot Study

Abstract:

Tetrahydrobiopterin (BH4), an essential cofactor of amino acid metabolism, was found to be strongly elevated in ME/CFS patients with Orthostatic intolerance (ME + OI). However, the molecular mechanism of BH4 upregulation is poorly understood in ME + OI patients. Here, we report that the activation of the non-oxidative pentose phosphate pathway (PPP) plays a critical role in the biosynthesis of BH4 in ME + OI patients.

Microarray-based gene screening followed by real-time PCR-based validation, ELISA assay, and finally enzyme kinetic studies of glucose-6-phosphate dehydrogenase (G6PDH), transaldolase (TALDO1), and transketolase (TK) enzymes revealed that the augmentation of anaerobic PPP is critical in the pathogenesis of ME + OI. Along with the upregulated anaerobic PPP enzymes, we observed that biopterin metabolites such as BH4 and dihydrobiopterin (BH2) are strongly upregulated suggesting the disruption of biopterin homeostasis in ME + OI patients.

To explore the molecular role of anaerobic PPP in biopterin metabolism, we devised a novel cell culture strategy to induce non-oxidative PPP by treating human microglial cells with ribose-5-phosphate (R5P) under a hypoxic condition of 85%N2/10%CO2/5%O2 followed by the analysis of BH4 and BH2 upregulation via ELISA, immunoblot and dual immunocytochemical analyses.

These results confirmed that the activation of non-oxidative PPP is indeed required for the upregulation of both BH4 and BH2. Moreover, the siRNA knocking down of the taldo1 gene strongly inhibited the expression of GTP cyclohydrolase 1 (GTPCH1) and subsequent production of BH4 and its metabolic conversion to BH2 in R5P-treated and hypoxia-induced C20 human microglia cells. To test the functional role of ME + OI plasma-derived biopterins, exogenously added plasma samples of ME + OI plasma with high BH4 upregulated inducible nitric oxide synthase (iNOS) and nitric oxide (NO) in human microglial cells indicating that the non-oxidative PPP-induced-biopterins could stimulate inflammatory response in ME + OI patients.

Source: Sarojini Bulbule, Carl Gunnar Gottschalk, Molly E Drosen et al. Augmentation of Anaerobic Pentose Phosphate Pathway Dysregulates Tetrahydrobiopterin Metabolism in Myalgic Encephalomyelitis/ Chronic Fatigue Syndrome (ME/CFS) Patients with Orthostatic Intolerance: A Pilot Study, 11 December 2023, PREPRINT (Version 1) available at Research Square [https://doi.org/10.21203/rs.3.rs-3716093/v1] https://www.researchsquare.com/article/rs-3716093/v1 (Full text)

Myalgic Encephalomyelitis-Chronic Fatigue Syndrome Common Data Element item content analysis

Abstract:

Introduction: Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a multisystem chronic disease estimated to affect 836,000-2.5 million individuals in the United States. Persons with ME/CFS have a substantial reduction in their ability to engage in pre-illness levels of activity. Multiple symptoms include profound fatigue, post-exertional malaise, unrefreshing sleep, cognitive impairment, orthostatic intolerance, pain, and other symptoms persisting for more than 6 months. Diagnosis is challenging due to fluctuating and complex symptoms. ME/CFS Common Data Elements (CDEs) were identified in the National Institutes of Health (NIH) National Institute of Neurological Disorders and Stroke (NINDS) Common Data Element Repository. This study reviewed ME/CFS CDEs item content.

Methods: Inclusion criteria for CDEs (measures recommended for ME/CFS) analysis: 1) assesses symptoms; 2) developed for adults; 3) appropriate for patient reported outcome measure (PROM); 4) does not use visual or pictographic responses. Team members independently reviewed CDEs item content using the World Health Organization International Classification of Functioning, Disability and Health (ICF) framework to link meaningful concepts.

Results: 119 ME/CFS CDEs (measures) were reviewed and 38 met inclusion criteria, yielding 944 items linked to 1503 ICF meaningful concepts. Most concepts linked to ICF Body Functions component (b-codes; n = 1107, 73.65%) as follows: Fatiguability (n = 220, 14.64%), Energy Level (n = 166, 11.04%), Sleep Functions (n = 137, 9.12%), Emotional Functions (n = 131, 8.72%) and Pain (n = 120, 7.98%). Activities and Participation concepts (d codes) accounted for a smaller percentage of codes (n = 385, 25.62%). Most d codes were linked to the Mobility category (n = 69, 4.59%) and few items linked to Environmental Factors (e codes; n = 11, 0.73%).

Discussion: Relatively few items assess the impact of ME/CFS symptoms on Activities and Participation. Findings support development of ME/CFS-specific PROMs, including items that assess activity limitations and participation restrictions. Development of psychometrically-sound, symptom-based item banks administered as computerized adaptive tests can provide robust assessments to assist primary care providers in the diagnosis and care of patients with ME/CFS.

Source: Slavin MD, Bailey HM, Hickey EJ, Vasudevan A, Ledingham A, Tannenbaum L, Bateman L, Kaufman DL, Peterson DL, Ruhoy IS, Systrom DM, Felsenstein D, Kazis LE. Myalgic Encephalomyelitis-Chronic Fatigue Syndrome Common Data Element item content analysis. PLoS One. 2023 Sep 12;18(9):e0291364. doi: 10.1371/journal.pone.0291364. PMID: 37698999. https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0291364 (Full text)

A multicenter virome analysis of blood, feces, and saliva in myalgic encephalomyelitis/chronic fatigue syndrome

Abstract:

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is estimated to affect 0.4%-2.5% of the global population. Most cases are unexplained; however, some patients describe an antecedent viral infection or response to antiviral medications.

We report here a multicenter study for the presence of viral nucleic acid in blood, feces, and saliva of patients with ME/CFS using polymerase chain reaction and high-throughput sequencing.

We found no consistent group-specific differences other than a lower prevalence of anelloviruses in cases compared to healthy controls. Our findings suggest that future investigations into viral infections in ME/CFS should focus on adaptive immune responses rather than surveillance for viral gene products.

Source: Briese T, Tokarz R, Bateman L, Che X, Guo C, Jain K, Kapoor V, Levine S, Hornig M, Oleynik A, Quan PL, Wong WH, Williams BL, Vernon SD, Klimas NG, Peterson DL, Montoya JG, Ian Lipkin W. A multicenter virome analysis of blood, feces, and saliva in myalgic encephalomyelitis/chronic fatigue syndrome. J Med Virol. 2023 Aug;95(8):e28993. doi: 10.1002/jmv.28993. PMID: 37526404. https://pubmed.ncbi.nlm.nih.gov/37526404/ 

Natural killer cytotoxicity in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS): a multi-site clinical assessment of ME/CFS (MCAM) sub-study

Abstract:

Background: Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a multisystem illness characterized by substantial reduction in function accompanied by profound unexplained fatigue not significantly relieved by rest, post-exertional malaise, and other symptoms. Reduced natural killer (NK) cell count and cytotoxicity has been investigated as a biomarker for ME/CFS, but few clinical laboratories offer the test and multi-site verification studies have not been conducted.

Methods: We determined NK cell counts and cytotoxicity in 174 (65%) ME/CFS, 86 (32%) healthy control (HC) and 10 (3.7%) participants with other fatigue associated conditions (ill control [IC]) from the Multi-Site Clinical Assessment of ME/CFS (MCAM) study using an assay validated for samples shipped overnight instead of testing on day of venipuncture.

Results: We found a large variation in percent cytotoxicity [mean and (IQR) for ME/CFS and HC respectively, 34.1% (IQR 22.4-44.3%) and 33.6% (IQR 22.9-43.7%)] and no statistically significant differences between patients with ME/CFS and HC (p-value = 0.79). Analysis stratified on illness domain measured with standardized questionnaires did not identify an association of NK cytotoxicity with domain scores. Among all participants, NK cytotoxicity was not associated with survey results of physical and mental well-being, or health factors such as history of infection, obesity, smoking, and co-morbid conditions.

Conclusion: These results indicate this assay is not ready for clinical implementation and studies are needed to further explore immune parameters that may be involved in the pathophysiology of ME/CFS.

Source: Querec TD, Lin JS, Chen Y, Helton B, Kogelnik AM, Klimas NG, Peterson DL, Bateman L, Lapp C, Podell RN, Natelson BH, Unger ER; MCAM Study Group. Natural killer cytotoxicity in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS): a multi-site clinical assessment of ME/CFS (MCAM) sub-study. J Transl Med. 2023 Apr 3;21(1):242. doi: 10.1186/s12967-023-03958-2. PMID: 37013608. https://translational-medicine.biomedcentral.com/articles/10.1186/s12967-023-03958-2 (Full text)

Altered Fatty Acid Oxidation in Lymphocyte Populations of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

Abstract:

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a disabling multisystem illness in which individuals are plagued with fatigue, inflammatory symptoms, cognitive dysfunction, and the hallmark symptom, post-exertional malaise. While the cause of this disease remains unknown, there is evidence of a potential infectious component that, along with patient symptoms and common onsets of the disease, implicates immune system dysfunction. To further our understanding of the state of ME/CFS lymphocytes, we characterized the role of fatty acids in isolated Natural Killer cells, CD4+ T cells, and CD8+ T cells in circulation and after overnight stimulation, through implicit perturbations to fatty acid oxidation.

We examined samples obtained from at least 8 and as many as 20 subjects for immune cell fatty acid characterization in a variety of experiments and found that all three isolated cell types increased their utilization of lipids and levels of pertinent proteins involved in this metabolic pathway in ME/CFS samples, particularly during higher energy demands and activation. In T cells, we characterized the cell populations contributing to these metabolic shifts, which included CD4+ memory cells, CD4+ effector cells, CD8+ naïve cells, and CD8+ memory cells.

We also discovered that patients with ME/CFS and healthy control samples had significant correlations between measurements of CD4+ T cell fatty acid metabolism and demographic data. These findings provide support for metabolic dysfunction in ME/CFS immune cells. We further hypothesize about the consequences that these altered fuel dependencies may have on T and NK cell effector function, which may shed light on the illness’s mechanism of action.

Source: Maya J, Leddy SM, Gottschalk CG, Peterson DL, Hanson MR. Altered Fatty Acid Oxidation in Lymphocyte Populations of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome. Int J Mol Sci. 2023 Jan 19;24(3):2010. doi: 10.3390/ijms24032010. PMID: 36768336; PMCID: PMC9916395. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9916395/ (Full text)

Potential molecular mechanisms of chronic fatigue in long haul COVID and other viral diseases

Abstract:

Historically, COVID-19 emerges as one of the most devastating diseases of humankind, which creates an unmanageable health crisis worldwide. Until now, this disease costs millions of lives and continues to paralyze human civilization’s economy and social growth, leaving an enduring damage that will take an exceptionally long time to repair.

While a majority of infected patients survive after mild to moderate reactions after two to six weeks, a growing population of patients suffers for months with severe and prolonged symptoms of fatigue, depression, and anxiety. These patients are no less than 10% of total COVID-19 infected individuals with distinctive chronic clinical symptomatology, collectively termed post-acute sequelae of COVID-19 (PASC) or more commonly long-haul COVID. Interestingly, Long-haul COVID and many debilitating viral diseases display a similar range of clinical symptoms of muscle fatigue, dizziness, depression, and chronic inflammation.

In our current hypothesis-driven review article, we attempt to discuss the molecular mechanism of muscle fatigue in long-haul COVID, and other viral diseases as caused by HHV6, Powassan, Epstein-Barr virus (EBV), and HIV. We also discuss the pathological resemblance of virus-triggered muscle fatigue with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS).

Source: Gottschalk CG, Peterson D, Armstrong J, Knox K, Roy A. Potential molecular mechanisms of chronic fatigue in long haul COVID and other viral diseases. Infect Agent Cancer. 2023 Feb 7;18(1):7. doi: 10.1186/s13027-023-00485-z. PMID: 36750846; PMCID: PMC9902840. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9902840/ (Full text)

Elevated ATG13 in serum of patients with ME/CFS stimulates oxidative stress response in microglial cells via activation of receptor for advanced glycation end products (RAGE)

Abstract:

Myalgic Encephalomyelitis, also known as Chronic Fatigue Syndrome (ME/CFS), is a multisystem illness characterized by extreme muscle fatigue associated with pain, neurocognitive impairment, and chronic inflammation. Despite intense investigation, the molecular mechanism of this disease is still unknown. Here we demonstrate that autophagy-related protein ATG13 is strongly upregulated in the serum of ME/CFS patients, indicative of impairment in the metabolic events of autophagy.

A Thioflavin T-based protein aggregation assay, array screening for autophagy-related factors, densitometric analyses, and confirmation with ELISA revealed that the level of ATG13 was strongly elevated in serum samples of ME/CFS patients compared to age-matched controls. Moreover, our microglia-based oxidative stress response experiments indicated that serum samples of ME/CFS patients evoke the production of reactive oxygen species (ROS) and nitric oxide in human HMC3 microglial cells, whereas neutralization of ATG13 strongly diminishes the production of ROS and NO, suggesting that ATG13 plays a role in the observed stress response in microglial cells. Finally, an in vitro ligand binding assay provided evidence that ATG13 employs the Receptor for Advanced Glycation End-products (RAGE) to stimulate ROS in microglial cells.

Collectively, our results suggest that an impairment of autophagy following the release of ATG13 into serum could be a pathological signal in ME/CFS.

Source: Gottschalk G, Peterson D, Knox K, Maynard M, Whelan RJ, Roy A. Elevated ATG13 in serum of patients with ME/CFS stimulates oxidative stress response in microglial cells via activation of receptor for advanced glycation end products (RAGE). Mol Cell Neurosci. 2022 Apr 26:103731. doi: 10.1016/j.mcn.2022.103731. Epub ahead of print. PMID: 35487443. https://www.sciencedirect.com/science/article/abs/pii/S1044743122000379?via%3Dihub (Full text)

Individualizing medical treatment in chronic fatigue syndrome/ myalgic encephalomyelitis: Evidence for effective medications and possible relevance to “Long-Hauler Syndrome” in Covid-19 affected patients

Abstract:

Large controlled studies of Chronic Fatigue Syndrome/Myalgic Encephalomyelitis (CFS/ME) have shown no effective medical treatment for this disorder. There are individual patients, however, with dramatic responses to some medications.

We report two patients with clear responses to rintatolimod and galantamine characterized by rapid reduction of symptoms on starting treatment and return of symptoms on withdrawal.

As in cancer, CFS/ME is a heterogeneous disorder but unlike most cancers, such as melanoma, breast cancer, and B-cell lymphoma, CFS/ME has no known biological marker that can distinguish between subtypes.

We suggest an approach to medical treatment of CFS/ME that could be utilized by primary caregivers that offer the possibility of more rapid and complete recovery from this debilitating disorder.

Current studies indicate that prolonged symptomatic recovery from infection with Covid-19 (“long hauler syndrome” or PASC, for post-acute sequelae of Covid-19) represents a severe form of CFS/ME and thus may also be amenable to personalized medicine with specific medications.

Source: Levine PH, Ajmera KM, Bjorke B, Peterson D. Individualizing medical treatment in chronic fatigue syndrome/myalgic
encephalomyelitis: Evidence for effective medications and possible relevance to “Long-Hauler Syndrome” in Covid-19 affected
patients. J Clin Images Med Case Rep. 2022; 3(1): 1681. https://jcimcr.org/pdfs/JCIMCR-v3-1681.pdf (Full text)

 

Evidence for Peroxisomal Dysfunction and Dysregulation of the CDP-Choline Pathway in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

Abstract:

Background: Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a chronic and debilitating disease that is characterized by unexplained physical fatigue unrelieved by rest. Symptoms also include cognitive and sensory dysfunction, sleeping disturbances, orthostatic intolerance, and gastrointestinal problems. A syndrome clinically similar to ME/CFS has been reported following well-documented infections with the coronaviruses SARS-CoV and MERS-CoV. At least 10% of COVID-19 survivors develop post acute sequelae of SARS-CoV-2 infection (PASC). Although many individuals with PASC have evidence of structural organ damage, a subset have symptoms consistent with ME/CFS including fatigue, post exertional malaise, cognitive dysfunction, gastrointestinal disturbances, and postural orthostatic intolerance. These common features in ME/CFS and PASC suggest that insights into the pathogenesis of either may enrich our understanding of both syndromes, and could expedite the development of strategies for identifying those at risk and interventions that prevent or mitigate disease.

Methods: Using regression, Bayesian and enrichment analyses, we conducted targeted and untargeted metabolomic analysis of 888 metabolic analytes in plasma samples of 106 ME/CFS cases and 91 frequency-matched healthy controls.

Results: In ME/CFS cases, regression, Bayesian and enrichment analyses revealed evidence of peroxisomal dysfunction with decreased levels of plasmalogens. Other findings included decreased levels of several membrane lipids, including phosphatidylcholines and sphingomyelins, that may indicate dysregulation of the cytidine-5’-diphosphocholine pathway. Enrichment analyses revealed decreased levels of choline, ceramides and carnitines, and increased levels of long chain triglycerides (TG) and hydroxy-eicosapentaenoic acid. Elevated levels of dicarboxylic acids were consistent with abnormalities in the tricarboxylic acid cycle. Using machine learning algorithms with selected metabolites as predictors, we were able to differentiate female ME/CFS cases from female controls (highest AUC=0.794) and ME/CFS cases without self-reported irritable bowel syndrome (sr-IBS) from controls without sr-IBS (highest AUC=0.873).

Conclusion: Our findings are consistent with earlier ME/CFS work indicating compromised energy metabolism and redox imbalance, and highlight new abnormalities that may provide insights into the pathogenesis of ME/CFS.

One sentence summary: Plasma levels of plasmalogens are decreased in patients with myalgic encephalomyelitis/chronic fatigue syndrome suggesting peroxisome dysfunction.

Source: Che X, Brydges CR, Yu Y, Price A, Joshi S, Roy A, Lee B, Barupal DK, Cheng A, Palmer DM, Levine S, Peterson DL, Vernon SD, Bateman L, Hornig M, Montoya JG, Komaroff AL, Fiehn O, Lipkin WI. Evidence for Peroxisomal Dysfunction and Dysregulation of the CDP-Choline Pathway in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome. medRxiv [Preprint]. 2022 Jan 11:2021.06.14.21258895. doi: 10.1101/2021.06.14.21258895. PMID: 35043127; PMCID: PMC8764736. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8764736/ (Full text)

Deficient butyrate-producing capacity in the gut microbiome of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome patients is associated with fatigue symptoms

Abstract:

Background Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a complex, debilitating disease of unknown cause for which there is no specific therapy. Patients suffering from ME/CFS commonly experience persistent fatigue, post-exertional malaise, cognitive dysfunction, sleep disturbances, orthostatic intolerance, fever and irritable bowel syndrome (IBS). Recent evidence implicates gut microbiome dysbiosis in ME/CFS. However, most prior studies are limited by small sample size, differences in clinical criteria used to define cases, limited geographic sampling, reliance on bacterial culture or 16S rRNA gene sequencing, or insufficient consideration of confounding factors that may influence microbiome composition. In the present study, we evaluated the fecal microbiome in the largest prospective, case-control study to date (n=106 cases, n=91 healthy controls), involving subjects from geographically diverse communities across the United States.

Results Using shotgun metagenomics and qPCR and rigorous statistical analyses that controlled for important covariates, we identified decreased relative abundance and quantity of FaecalibacteriumRoseburia, and Eubacterium species and increased bacterial load in feces of subjects with ME/CFS. These bacterial taxa play an important role in the production of butyrate, a multifunctional bacterial metabolite that promotes human health by regulating energy metabolism, inflammation, and intestinal barrier function. Functional metagenomic and qPCR analyses were consistent with a deficient microbial capacity to produce butyrate along the acetyl-CoA pathway in ME/CFS. Metabolomic analyses of short-chain fatty acids (SCFAs) confirmed that fecal butyrate concentration was significantly reduced in ME/CFS. Further, we found that the degree of deficiency in butyrate-producing bacteria correlated with fatigue symptom severity among ME/CFS subjects. Finally, we provide evidence that IBS comorbidity is an important covariate to consider in studies investigating the microbiome of ME/CFS subjects, as differences in microbiota alpha diversity, some bacterial taxa, and propionate were uniquely associated with self-reported IBS diagnosis.

Conclusions Our findings indicate that there is a core deficit in the butyrate-producing capacity of the gut microbiome in ME/CFS subjects compared to healthy controls. The relationships we observed among symptom severity and these gut microbiome disturbances may be suggestive of a pathomechanistic linkage, however, additional research is warranted to establish any causal relationship. These findings provide support for clinical trials that explore the utility of dietary, probiotic and prebiotic interventions to boost colonic butyrate production in ME/CFS.

Source: Cheng Guo, Xiaoyu Che, Thomas Briese, Orchid Allicock, Rachel A. Yates, Aaron Cheng, Amit Ranjan, Dana March, Mady Hornig, Anthony L. Komaroff, Susan Levine, Lucinda Bateman, Suzanne D. Vernon, Nancy G. Klimas, Jose G. Montoya, Daniel L. Peterson, W. Ian Lipkin, Brent L. Williams. Deficient butyrate-producing capacity in the gut microbiome of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome patients is associated with fatigue symptoms. medRxiv 2021.10.27.21265575; doi: https://doi.org/10.1101/2021.10.27.21265575 https://www.medrxiv.org/content/10.1101/2021.10.27.21265575v1?fbclid=IwAR16pb6by73xZx5lZM3j-5dOc_YT2JapILaRS-DcUZj5EHZxnoSa2fAAIuE (Full text available to download)