Local immune response to food antigens drives meal-induced abdominal pain

Abstract:

Up to 20% of people worldwide develop gastrointestinal symptoms following a meal1, leading to decreased quality of life, substantial morbidity and high medical costs. Although the interest of both the scientific and lay communities in this issue has increased markedly in recent years, with the worldwide introduction of gluten-free and other diets, the underlying mechanisms of food-induced abdominal complaints remain largely unknown. Here we show that a bacterial infection and bacterial toxins can trigger an immune response that leads to the production of dietary-antigen-specific IgE antibodies in mice, which are limited to the intestine.

Following subsequent oral ingestion of the respective dietary antigen, an IgE- and mast-cell-dependent mechanism induced increased visceral pain. This aberrant pain signalling resulted from histamine receptor H1-mediated sensitization of visceral afferents. Moreover, injection of food antigens (gluten, wheat, soy and milk) into the rectosigmoid mucosa of patients with irritable bowel syndrome induced local oedema and mast cell activation. Our results identify and characterize a peripheral mechanism that underlies food-induced abdominal pain, thereby creating new possibilities for the treatment of irritable bowel syndrome and related abdominal pain disorders.

Source: Aguilera-Lizarraga, J., Florens, M.V., Viola, M.F. et al. Local immune response to food antigens drives meal-induced abdominal pain. Nature (2021). https://doi.org/10.1038/s41586-020-03118-2 https://www.nature.com/articles/s41586-020-03118-2#Abs1

Exercise modifies glutamate and other metabolic biomarkers in cerebrospinal fluid from Gulf War Illness and Myalgic encephalomyelitis / Chronic Fatigue Syndrome

Abstract:

Myalgic encephalomyelitis / Chronic Fatigue Syndrome (ME/CFS) and Gulf War Illness (GWI) share many symptoms of fatigue, pain, and cognitive dysfunction that are not relieved by rest. Patterns of serum metabolites in ME/CFS and GWI are different from control groups and suggest potential dysfunction of energy and lipid metabolism. The metabolomics of cerebrospinal fluid was contrasted between ME/CFS, GWI and sedentary controls in 2 sets of subjects who had lumbar punctures after either (a) rest or (b) submaximal exercise stress tests. Postexercise GWI and control subjects were subdivided according to acquired transient postexertional postural tachycardia. Banked cerebrospinal fluid specimens were assayed using Biocrates AbsoluteIDQ® p180 kits for quantitative targeted metabolomics studies of amino acids, amines, acylcarnitines, sphingolipids, lysophospholipids, alkyl and ether phosphocholines.

Glutamate was significantly higher in the subgroup of postexercise GWI subjects who did not develop postural tachycardia after exercise compared to nonexercise and other postexercise groups. The only difference between nonexercise groups was higher lysoPC a C28:0 in GWI than ME/CFS suggesting this biochemical or phospholipase activities may have potential as a biomarker to distinguish between the 2 diseases. Exercise effects were suggested by elevation of short chain acylcarnitine C5-OH (C3-DC-M) in postexercise controls compared to nonexercise ME/CFS. Limitations include small subgroup sample sizes and absence of postexercise ME/CFS specimens. Mechanisms of glutamate neuroexcitotoxicity may contribute to neuropathology and “neuroinflammation” in the GWI subset who did not develop postural tachycardia after exercise. Dysfunctional lipid metabolism may distinguish the predominantly female ME/CFS group from predominantly male GWI subjects.

Source: Baraniuk JN, Kern G, Narayan V, Cheema A. Exercise modifies glutamate and other metabolic biomarkers in cerebrospinal fluid from Gulf War Illness and Myalgic encephalomyelitis / Chronic Fatigue Syndrome. PLoS One. 2021 Jan 13;16(1):e0244116. doi: 10.1371/journal.pone.0244116. PMID: 33440400. https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0244116 (Full text)

Will COVID-19 Lead to ME/CFS?

INTRODUCTION:

“Recovering” from COVID-19 does not guarantee a return to a person’s usual state of health. For one thing, some people with multi-system injury—particularly to the brain, heart and kidneys—may develop permanent dysfunction of those organs.
In addition, a more subtle form of chronic illness may develop. For some people with COVID-19, even those who are mildly affected at first, the ensuing weeks and months of “recovery” bring a surprise and a betrayal: they do not return to full health. Although nucleic acid tests no longer detect the virus, people still suffer from ongoing symptoms. They call themselves “long haulers”, and the condition is being called “long COVID”.

Source: Anthony L. Komaroff and Lucinda Bateman. Will COVID-19 Lead to ME/CFS? Front. Med. | doi: 10.3389/fmed.2020.606824 https://www.frontiersin.org/articles/10.3389/fmed.2020.606824/full (Full text)

High Prevalence of Perineural Cysts in Patients with Fibromyalgia and Chronic Fatigue Syndrome

Abstract:

Objective: Pain in fibromyalgia (FM) and chronic fatigue syndrome (CFS) is assumed to originate from central sensitization. Perineural cysts or Tarlov cysts (TCs) are nerve root dilations resulting from pathologically increased cerebrospinal fluid pressure. These cysts initially affect sensory neurons and axons in dorsal root ganglia and produce sensory symptoms (pain and paresthesia). Symptomatic TC (STC) patients often complain about widespread pain and fatigue. Consequently, STC patients may initially be diagnosed with FM, CFS, or both. The objective of this study was to document the prevalence of TCs in patients diagnosed with FM or CFS.

Design: A retrospective study.

Setting: An outpatient clinic for musculoskeletal disorders.

Subjects: Patients diagnosed with FM according to the 1990 American College of Rheumatology criteria or with CFS according to the 1994 Centers for Disease Control criteria were selected.

Methods: Review of lumbar and sacral magnetic resonance imaging scans including TCs ≥5 mm in size.

Results: In total, 197 patients with FM, CFS, or both underwent magnetic resonance imaging. Ninety-one percent were women. The mean age was 48.1 (±11.9) years. TCs were observed in 39% of patients, with a mean size of 11.8 (±5.2) mm. In males, the prevalence was 12%, vs. 42% in females.

Conclusions: In patients diagnosed with FM or CFS, the prevalence of TCs was three times higher than that in the general population. This observation supports the hypothesis that STCs, FM, and CFS may share the same pathophysiological mechanism, i.e., moderately increased cerebrospinal fluid pressure, causing irritation of neurons and axons in dorsal root ganglia.

Source: Hulens M, Bruyninckx F, Dankaerts W, Rasschaert R, De Mulder P, Stalmans I, Vansant G, Bervoets C. High Prevalence of Perineural Cysts in Patients with Fibromyalgia and Chronic Fatigue Syndrome. Pain Med. 2020 Dec 1:pnaa410. doi: 10.1093/pm/pnaa410. Epub ahead of print. PMID: 33260218. https://pubmed.ncbi.nlm.nih.gov/33260218/

Multi-omics examination of Q fever fatigue syndrome identifies similarities with chronic fatigue syndrome

Abstract:

Background: Q fever fatigue syndrome (QFS) is characterised by a state of prolonged fatigue that is seen in 20% of acute Q fever infections and has major health-related consequences. The molecular mechanisms underlying QFS are largely unclear. In order to better understand its pathogenesis, we applied a multi-omics approach to study the patterns of the gut microbiome, blood metabolome, and inflammatory proteome of QFS patients, and compared these with those of chronic fatigue syndrome (CFS) patients and healthy controls (HC).

Methods: The study population consisted of 31 QFS patients, 50 CFS patients, and 72 HC. All subjects were matched for age, gender, and general geographical region (South-East part of the Netherlands). The gut microbiome composition was assessed by Metagenomic sequencing using the Illumina HiSeq platform. A total of 92 circulating inflammatory markers were measured using Proximity Extension Essay and 1607 metabolic features were assessed with a high-throughput non-targeted metabolomics approach.

Results: Inflammatory markers, including 4E-BP1 (P = 9.60-16 and 1.41-7) and MMP-1 (P = 7.09-9 and 3.51-9), are significantly more expressed in both QFS and CFS patients compared to HC. Blood metabolite profiles show significant differences when comparing QFS (319 metabolites) and CFS (441 metabolites) patients to HC, and are significantly enriched in pathways like sphingolipid (P = 0.0256 and 0.0033) metabolism. When comparing QFS to CFS patients, almost no significant differences in metabolome were found. Comparison of microbiome taxonomy of QFS and CFS patients with that of HC, shows both in- and decreases in abundancies in Bacteroidetes (with emphasis on Bacteroides and Alistiples spp.), and Firmicutes and Actinobacteria (with emphasis on Ruminococcus and Bifidobacterium spp.). When we compare QFS patients to CFS patients, there is a striking resemblance and hardly any significant differences in microbiome taxonomy are found.

Conclusions: We show that QFS and CFS patients are similar across three different omics layers and 4E-BP1 and MMP-1 have the potential to distinguish QFS and CFS patients from HC.

Source: Raijmakers RPH, Roerink ME, Jansen AFM, Keijmel SP, Gacesa R, Li Y, Joosten LAB, van der Meer JWM, Netea MG, Bleeker-Rovers CP, Xu CJ. Multi-omics examination of Q fever fatigue syndrome identifies similarities with chronic fatigue syndrome. J Transl Med. 2020 Nov 26;18(1):448. doi: 10.1186/s12967-020-02585-5. PMID: 33243243. https://translational-medicine.biomedcentral.com/articles/10.1186/s12967-020-02585-5  (Full text)

Not what it seems to be: Depression versus periodic limb movement disorder

Abstract:

Sleep disorders often disturb sleep. Daytime symptoms of disturb sleep mimic that of depression, somatoform disorder, fibromyalgia and chronic fatigue syndrome. We are presenting a case of depression who was not responding to antidepressant therapy. Based on clinical history, diagnosis was changed to chronic fatigue syndrome and in view of prominent sleep disturbances, polysomnography was done. Based on sleep study data, diagnosis of periodic limb movement disorder was made and he was started on ropinirole, that improved his symptoms.

Source: Gupta R, Kundu K, Khayyam K, Saini LK. Not what it seems to be: Depression versus periodic limb movement disorder. Indian J Psychiatry. 2020 Jul-Aug;62(4):437-439. doi: 10.4103/psychiatry.IndianJPsychiatry_450_19. Epub 2020 Jul 27. PMID: 33165358; PMCID: PMC7597704. https://pubmed.ncbi.nlm.nih.gov/33165358/

Post COVID-19 syndrome associated with orthostatic cerebral hypoperfusion syndrome, small fiber neuropathy and benefit of immunotherapy: a case report

Abstract:

Coronavirus disease (COVID-19) is a novel highly contagious infectious disease caused by the coronavirus SARS-CoV2. The virus affects the human respiratory and other systems, and presents mostly as acute respiratory syndrome with fever, fatigue, dry cough, myalgia and dyspnea. The clinical manifestations vary from no symptoms to multiple organ failure. Majority of patients fully recover. Several postinfectious presumably autoimmune complications of COVID-19 affecting the brain or peripheral large nerve fibers have been reported. This report describes a post COVID-19 patient who developed chronic fatigue, orthostatic dizziness and brain fog consistent with orthostatic hypoperfusion syndrome (OCHOS), a form of orthostatic intolerance, and painful small fiber neuropathy (SFN). Initially, the patient was diagnosed with. OCHOS (detected by the tilt test with transcranial Doppler monitoring) and SFN (confirmed by skin biopsy), and both OCHOS/SFN were attributed to Post Treatment Lyme Disease Syndrome of presumed autoimmune etiology. Patient recovered on symptomatic therapy. COVID-19 triggered exacerbation of OCHOS/SFN responded to immunotherapy with intravenous immunoglobulins. This case suggests that post COVID-19 syndrome may present as an autoimmune OCHOS/SFN and that early immunotherapy may be effective. Further studies are necessary to confirm the link between OCHOS/SFN and COVID-19 disease as well as to confirm the benefit of immunotherapy.

Source: Novak P. Post COVID-19 syndrome associated with orthostatic cerebral hypoperfusion syndrome, small fiber neuropathy and benefit of immunotherapy: a case report. eNeurologicalSci. 2020 Dec;21:100276. doi: 10.1016/j.ensci.2020.100276. Epub 2020 Sep 20. PMID: 32984564; PMCID: PMC7502253. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7502253/ (Full text)

An analysis of 2‐day cardiopulmonary exercise testing to assess unexplained fatigue

Abstract:

Two consecutive maximal cardiopulmonary exercise tests (CPETs) performed 24 hr apart (2-day CPET protocol) are increasingly used to evaluate post-exertional malaise (PEM) and related disability among individuals with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). This protocol may extend to other fatiguing illnesses with similar characteristics to ME/CFS; however, 2-day CPET protocol reliability and minimum change required to be considered clinically meaningful (i.e., exceeding the standard error of the measure) are not well characterized. To address this gap, we evaluated the 2-day CPET protocol in Gulf War Illness (GWI) by quantifying repeatability of seven CPET parameters, establishing their thresholds of clinically significant change, and determining whether changes differed between veterans with GWI and controls.

Excluding those not attaining peak effort criteria (n = 15), we calculated intraclass correlation coefficients (ICCs), the smallest real difference (SRD%), and repeated measures analysis of variance (RM-ANOVA) at the ventilatory anaerobic threshold (VAT) and peak exercise in 15 veterans with GWI and eight controls. ICC values at peak ranged from moderate to excellent for veterans with GWI (mean [range]; 0.84 [0.65 – 0.92]) and were reduced at the VAT (0.68 [0.37 – 0.78]).

Across CPET variables, the SRD% at peak exercise for veterans with GWI (18.8 [8.8 – 28.8]) was generally lower than at the VAT (28.1 [9.5 – 34.8]). RM-ANOVAs did not detect any significant group-by-time interactions (all p > .05). The methods and findings reported here provide a framework for evaluating 2-day CPET reliability, and reinforce the importance of carefully considering measurement error in the population of interest when interpreting findings.

Source: Lindheimer JB, Alexander T, Qian W, et al. An analysis of 2-day cardiopulmonary exercise testing to assess unexplained fatigue. Physiol Rep. 2020;8(17):e14564. doi:10.14814/phy2.14564 (Full text) https://physoc.onlinelibrary.wiley.com/doi/full/10.14814/phy2.14564

Using Plasma Autoantibodies of Central Nervous System Proteins to Distinguish Veterans with Gulf War Illness from Healthy and Symptomatic Controls

Abstract:

For the past 30 years, there has been a lack of objective tools for diagnosing Gulf War Illness (GWI), which is largely characterized by central nervous system (CNS) symptoms emerging from 1991 Gulf War (GW) veterans. In a recent preliminary study, we reported the presence of autoantibodies against CNS proteins in the blood of veterans with GWI, suggesting a potential objective biomarker for the disorder.

Now, we report the results of a larger, confirmatory study of these objective biomarkers in 171 veterans with GWI compared to 60 healthy GW veteran controls and 85 symptomatic civilian controls (n = 50 myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and n = 35 irritable bowel syndrome (IBS)). Specifically, we compared plasma markers of CNS autoantibodies for diagnostic characteristics of the four groups (GWI, GW controls, ME/CFS, IBS).

For veterans with GWI, the results showed statistically increased levels of nine of the ten autoantibodies against neuronal “tubulin, neurofilament protein (NFP), Microtubule Associated Protein-2 (MAP-2), Microtubule Associated Protein-Tau (Tau), alpha synuclein (α-syn), calcium calmodulin kinase II (CaMKII)” and glial proteins “Glial Fibrillary Acidic Protein (GFAP), Myelin Associated Glycoprotein (MAG), Myelin Basic Protein (MBP), S100B” compared to healthy GW controls as well as civilians with ME/CFS and IBS.

Next, we summed all of the means of the CNS autoantibodies for each group into a new index score called the Neurodegeneration Index (NDI). The NDI was calculated for each tested group and showed veterans with GWI had statistically significantly higher NDI values than all three control groups. The present study confirmed the utility of the use of plasma autoantibodies for CNS proteins to distinguish among veterans with GWI and other healthy and symptomatic control groups.

Source: Mohamed B. Abou-Donia, Elizabeth S. Lapadula, Maxine H. Krengel, Emily Quinn, Jessica LeClair, Joseph Massaro, Lisa A. Conboy, Efi Kokkotou, Maria Abreu, Nancy G. Klimas, Daniel D. Nguyen and Kimberly Sullivan.  Using Plasma Autoantibodies of Central Nervous System Proteins to Distinguish Veterans with Gulf War Illness from Healthy and Symptomatic Controls. Brain Sci. 2020, 10(9), 610; https://doi.org/10.3390/brainsci10090610  https://www.mdpi.com/2076-3425/10/9/610/htm (Full text)

Exercise alters brain activation in Gulf War Illness and Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

Abstract:

Gulf War Illness affects 25–30% of American veterans deployed to the 1990–91 Persian Gulf War and is characterized by cognitive post-exertional malaise following physical effort. Gulf War Illness remains controversial since cognitive post-exertional malaise is also present in the more common Myalgic Encephalomyelitis/Chronic Fatigue Syndrome. An objective dissociation between neural substrates for cognitive post-exertional malaise in Gulf War Illness and Myalgic Encephalomyelitis/Chronic Fatigue Syndrome would represent a biological basis for diagnostically distinguishing these two illnesses.

Here, we used functional magnetic resonance imaging to measure neural activity in healthy controls and patients with Gulf War Illness and Myalgic Encephalomyelitis/Chronic Fatigue Syndrome during an N-back working memory task both before and after exercise. Whole brain activation during working memory (2-Back > 0-Back) was equal between groups prior to exercise. Exercise had no effect on neural activity in healthy controls yet caused deactivation within dorsal midbrain and cerebellar vermis in Gulf War Illness relative to Myalgic Encephalomyelitis/Chronic Fatigue Syndrome patients.

Further, exercise caused increased activation among Myalgic Encephalomyelitis/Chronic Fatigue Syndrome patients within the dorsal midbrain, left operculo-insular cortex (Rolandic operculum) and right middle insula. These regions-of-interest underlie threat assessment, pain, interoception, negative emotion and vigilant attention. As they only emerge post-exercise, these regional differences likely represent neural substrates of cognitive post-exertional malaise useful for developing distinct diagnostic criteria for Gulf War Illness and Myalgic Encephalomyelitis/Chronic Fatigue Syndrome.

Source: Stuart D Washington, Rakib U Rayhan, Richard Garner, Destie Provenzano, Kristina Zajur, Florencia Martinez Addiego, John W VanMeter, James N Baraniuk, Exercise alters brain activation in Gulf War Illness and Myalgic Encephalomyelitis/Chronic Fatigue Syndrome, Brain Communications, Volume 2, Issue 2, 2020, fcaa070, https://doi.org/10.1093/braincomms/fcaa070 https://academic.oup.com/braincomms/article/2/2/fcaa070/5885074 (Full text)