Tag: proinflammatory cytokines

Chronic fatigue syndrome from vagus nerve infection: a psychoneuroimmunological hypothesis

Abstract:

Chronic fatigue syndrome (CFS) is an often-debilitating condition of unknown origin. There is a general consensus among CFS researchers that the symptoms seem to reflect an ongoing immune response, perhaps due to viral infection. Thus, most CFS research has focused upon trying to uncover that putative immune system dysfunction or specific pathogenic agent. However, no single causative agent has been found.

In this speculative article, I describe a new hypothesis for the etiology of CFS: infection of the vagus nerve. When immune cells of otherwise healthy individuals detect any peripheral infection, they release proinflammatory cytokines. Chemoreceptors of the sensory vagus nerve detect these localized proinflammatory cytokines, and send a signal to the brain to initiate sickness behavior. Sickness behavior is an involuntary response that includes fatigue, fever, myalgia, depression, and other symptoms that overlap with CFS.

The vagus nerve infection hypothesis of CFS contends that CFS symptoms are a pathologically exaggerated version of normal sickness behavior that can occur when sensory vagal ganglia or paraganglia are themselves infected with any virus or bacteria. Drawing upon relevant findings from the neuropathic pain literature, I explain how pathogen-activated glial cells can bombard the sensory vagus nerve with proinflammatory cytokines and other neuroexcitatory substances, initiating an exaggerated and intractable sickness behavior signal. According to this hypothesis, any pathogenic infection of the vagus nerve can cause CFS, which resolves the ongoing controversy about finding a single pathogen. The vagus nerve infection hypothesis offers testable hypotheses for researchers, animal models, and specific treatment strategies.

Copyright © 2013 Elsevier Ltd. All rights reserved.

 

Source: VanElzakker MB. Chronic fatigue syndrome from vagus nerve infection: a psychoneuroimmunological hypothesis. Med Hypotheses. 2013 Sep;81(3):414-23. doi: 10.1016/j.mehy.2013.05.034. Epub 2013 Jun 19. https://www.ncbi.nlm.nih.gov/pubmed/23790471

 

Daily cytokine fluctuations, driven by leptin, are associated with fatigue severity in chronic fatigue syndrome: evidence of inflammatory pathology

Abstract:

BACKGROUND: Chronic fatigue syndrome (CFS) is a debilitating disorder characterized by persistent fatigue that is not alleviated by rest. The lack of a clearly identified underlying mechanism has hindered the development of effective treatments. Studies have demonstrated elevated levels of inflammatory factors in patients with CFS, but findings are contradictory across studies and no biomarkers have been consistently supported. Single time-point approaches potentially overlook important features of CFS, such as fluctuations in fatigue severity. We have observed that individuals with CFS demonstrate significant day-to-day variability in their fatigue severity.

METHODS: Therefore, to complement previous studies, we implemented a novel longitudinal study design to investigate the role of cytokines in CFS pathophysiology. Ten women meeting the Fukuda diagnostic criteria for CFS and ten healthy age- and body mass index (BMI)-matched women underwent 25 consecutive days of blood draws and self-reporting of symptom severity. A 51-plex cytokine panel via Luminex was performed for each of the 500 serum samples collected. Our primary hypothesis was that daily fatigue severity would be significantly correlated with the inflammatory adipokine leptin, in the women with CFS and not in the healthy control women. As a post-hoc analysis, a machine learning algorithm using all 51 cytokines was implemented to determine whether immune factors could distinguish high from low fatigue days.

RESULTS: Self-reported fatigue severity was significantly correlated with leptin levels in six of the participants with CFS and one healthy control, supporting our primary hypothesis. The machine learning algorithm distinguished high from low fatigue days in the CFS group with 78.3% accuracy.

CONCLUSIONS: Our results support the role of cytokines in the pathophysiology of CFS.

 

Source: Stringer EA, Baker KS, Carroll IR, Montoya JG, Chu L, Maecker HT, Younger JW. Daily cytokine fluctuations, driven by leptin, are associated with fatigue severity in chronic fatigue syndrome: evidence of inflammatory pathology. J Transl Med. 2013 Apr 9;11:93. doi: 10.1186/1479-5876-11-93. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3637529/ (Full article)

 

Inflammatory and cell-mediated immune biomarkers in myalgic encephalomyelitis/chronic fatigue syndrome and depression: inflammatory markers are higher in myalgic encephalomyelitis/chronic fatigue syndrome than in depression

Abstract:

BACKGROUND: Depression is an inflammatory disorder while many authors declare myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) to be a functional disorder. The aim of the present study is to compare inflammatory and cell-mediated immune (CMI) responses between depression and ME/CFS.

METHODS: We measured two proinflammatory cytokines (PICs) in plasma, interleukin-1 (IL-1) and tumor necrosis factor-α (TNF-α), with enzyme-linked immunosorbent assays, and serum neopterin with a radioimmunoassay in controls, ME/CFS and depressive patients.

RESULTS: Plasma PICs were significantly higher in ME/CFS than in depression and higher in both patient groups than in controls. Increased PIC levels in depression were attributable to the presence of fatigue and physio-somatic symptoms. Serum neopterin did not differ significantly between depression and ME/CFS but was higher in both patient groups than in controls. The significant positive correlations between neopterin and either IL-1 or TNF-α were significantly greater in depression than in ME/CFS.

CONCLUSIONS: Since PICs cause depression-like behaviors and fatigue/malaise, we suggest that inflammation may play a role in the pathophysiology of ME/CFS and depression. Increased neopterin also seems to contribute to the pathophysiology of both disorders. This study has detected a shared ‘pathway phenotype’, i.e. disorders in inflammatory and CMI pathways, which underpins both ME/CFS and depression and, therefore, may explain the co-occurrence of both disorders. ME/CFS and depression are discriminated from each other by increased PICs in ME/CFS and differences in the immune cell communication networks.

Copyright © 2012 S. Karger AG, Basel.

 

Source: Maes M, Twisk FN, Ringel K. Inflammatory and cell-mediated immune biomarkers in myalgic encephalomyelitis/chronic fatigue syndrome and depression: inflammatory markers are higher in myalgic encephalomyelitis/chronic fatigue syndrome than in depression. Psychother Psychosom. 2012;81(5):286-95. doi: 10.1159/000336803. Epub 2012 Jul 20. https://www.ncbi.nlm.nih.gov/pubmed/22832503

 

Evidence for inflammation and activation of cell-mediated immunity in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS): increased interleukin-1, tumor necrosis factor-α, PMN-elastase, lysozyme and neopterin

Abstract:

BACKGROUND: There is evidence that inflammatory pathways and cell-mediated immunity (CMI) play an important role in the pathophysiology of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS). Activation of inflammatory and CMI pathways, including increased levels of cytokines, is known to induce fatigue and somatic symptoms. Given the broad spectrum inflammatory state in ME/CFS, the aim of this study was to examine whether inflammatory and CMI biomarkers are increased in individuals with ME/CFS.

METHODS: In this study we therefore measured plasma interleukin-(IL)1, tumor necrosis factor (TNF)α, and PMN-elastase, and serum neopterin and lysozyme in 107 patients with ME/CFS, 37 patients with chronic fatigue (CF), and 20 normal controls. The severity of ME/CFS was measured with the Fibromyalgia and Chronic Fatigue Syndrome (FF) Rating Scale.

RESULTS: Serum IL-1, TNFα, neopterin and lysozyme are significantly higher in patients with ME/CFS than in controls and CF patients. Plasma PMN-elastase is significantly higher in patients with ME/CFS than in controls and CF patients and higher in the latter than in controls. Increased IL-1 and TNFα are significantly correlated with fatigue, sadness, autonomic symptoms, and a flu-like malaise; neopterin is correlated with fatigue, autonomic symptoms, and a flu-like malaise; and increased PMN-elastase is correlated with concentration difficulties, failing memory and a subjective experience of infection.

CONCLUSIONS: The findings show that ME/CFS is characterized by low-grade inflammation and activation of CMI. The results suggest that characteristic symptoms of ME/CFS, such as fatigue, autonomic symptoms and a flu-like malaise, may be caused by inflammatory mediators, e.g. IL-1 and TNFα.

Copyright © 2011 Elsevier B.V. All rights reserved.

 

Source: Maes M, Twisk FN, Kubera M, Ringel K. Evidence for inflammation and activation of cell-mediated immunity in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS): increased interleukin-1, tumor necrosis factor-α, PMN-elastase, lysozyme and neopterin. J Affect Disord. 2012 Feb;136(3):933-9. doi: 10.1016/j.jad.2011.09.004. Epub 2011 Oct 4. https://www.ncbi.nlm.nih.gov/pubmed/21975140

 

Curcumin, a polyphenolic antioxidant, attenuates chronic fatigue syndrome in murine water immersion stress model

Abstract:

Chronic fatigue syndrome, infection and oxidative stress are interrelated in epidemiological case studies. However, data demonstrating scientific validation of epidemiological claims regarding effectiveness of nutritional supplements for chronic fatigue syndrome are lacking. This study is designed to evaluate the effect of natural polyphenol, curcumin, in a mouse model of immunologically induced fatigue, where purified lipopolysaccharide (LPS) and Brucella abortus (BA) antigens were used as immunogens.

The assessment of chronic fatigue syndrome was based on chronic water-immersion stress test for 10 min daily for 19 days and the immobility time was taken as the marker of fatigue. Mice challenged with LPS or BA for 19 days showed significant increase in the immobility time and hyperalgesia on day 19, as well as marked increase in serum tumor necrosis factor-alpha (TNF-alpha) levels. Concurrent treatment with curcumin resulted in significantly decreased immobility time as well as hyperalgesia. There was significant attenuation of oxidative stress as well as TNF-alpha levels.

These findings strongly suggest that during immunological activation, there is significant increase in oxidative stress and curcumin can be a valuable option in the treatment of chronic fatigue syndrome.

 

Source: Gupta A, Vij G, Sharma S, Tirkey N, Rishi P, Chopra K. Curcumin, a polyphenolic antioxidant, attenuates chronic fatigue syndrome in murine water immersion stress model. Immunobiology. 2009;214(1):33-9. doi: 10.1016/j.imbio.2008.04.003. Epub 2008 Jun 17. https://www.ncbi.nlm.nih.gov/pubmed/19159825

 

A first study of cytokine genomic polymorphisms in CFS: Positive association of TNF-857 and IFNgamma 874 rare alleles

Abstract:

OBJECTIVE: In the past two years we have developed a biological bank of genomic DNA, cDNA, serum and red blood cells of Italian patients with certified CFS from the two Italian referral centers for the syndrome. Recent studies have shown an imbalance in cytokine production in disease states similar to Chronic Fatigue Syndrome (CFS), such as sickness behavior, both in animals and in humans. However we notice that serum cytokine concentrations are often inconstant and degrade rapidly. With this in mind, we investigated cytokine gene polymorphisms in 80 Italian patients with CFS in order to ascertain whether in this group of patients it is possible to describe a genetic predisposition to an inflammatory response.

METHODS: We analyzed the promoter polymorphisms of IL-10, IL-6 and the IFNgamma 874 T/A polymorphism in intron 1 with a PCR-SSP method (Cytogen One Lambda Inc. Canoga Park, CA, U.S.A) in 54 patients and TNF-308 G/A and -857 C/T promoter polymorphisms with a PCR-RFLP method (in 54 and 80 patients respectively).

RESULTS: There is a highly significant increase of TNF -857 TT and CT genotypes (p = 0.002) among patients with respect to controls and a significant decrease of IFN gamma low producers (A/A) (p = 0.04) among patients with respect to controls.

CONCLUSIONS: We hypothesize that CFS patients can have a genetic predisposition to an immunomodulatory response of an inflammatory nature probably secondary to one or more environmental insults of unknown nature.

 

Source: Carlo-Stella N, Badulli C, De Silvestri A, Bazzichi L, Martinetti M, Lorusso L, Bombardieri S, Salvaneschi L, Cuccia M, Carlo-Stella N, Badulli C, De Silvestri A, Bazzichi L, Martinetti M, Lorusso L, Bombardieri S, Salvaneschi L, Cuccia M. A first study of cytokine genomic polymorphisms in CFS: Positive association of TNF-857 and IFNgamma 874 rare alleles. Clin Exp Rheumatol. 2006 Mar-Apr;24(2):179-82. https://www.ncbi.nlm.nih.gov/pubmed/16762155

 

Stress-induced changes in LPS-induced pro-inflammatory cytokine production in chronic fatigue syndrome

Abstract:

OBJECTIVE: It has been suggested that a hypofunctional hypothalamic-pituitary-adrenal (HPA) axis in chronic fatigue syndrome could result in an exaggerated release of pro-inflammatory cytokines during stress. As pro-inflammatory cytokines are involved in the induction of sickness behavior and thus constitute a potential physiological correlate of stress-induced symptom exacerbation in chronic fatigue syndrome, we set out to evaluate the LPS-induced production of pro-inflammatory cytokines during psychosocial stress in CFS and healthy controls.

METHOD: Twenty-one CFS patients and 20 healthy controls matched for age and gender underwent a standardized psychosocial stress test (Trier social stress test, TSST). Adrenocorticotropine hormone (ACTH), salivary cortisol and plasma cortisol levels were measured before and repeatedly following exposure to the stressor. Lipopolysaccharide-stimulated production of interleukin-6 and tumor necrosis factor-alpha were assessed at baseline as well as 10 and 60 min after the stress test.

RESULTS: CFS patients showed an inverse stress-induced response pattern of LPS-stimulated cytokines responses in comparison to healthy controls, i.e. stimulated cytokine production decreased shortly after stress in CFS patients, while it increased in controls. Fatigue scores and basal LPS-induced cytokine levels were significantly associated for TNF-alpha in controls and for both cytokines in CFS patients. Stress-induced changes in stimulated cytokine production were not associated with general fatigue scores in the control group, whereas in the CFS group, fatigue scores were significantly correlated with integrated levels of LPS-induced cytokines. However, partial correlations revealed that these results were due to the high correlations with basal LPS-induced cytokine levels.

CONCLUSION: CFS patients do not show an exaggerated secretion of LPS-induced cytokines. Although cortisol responses to stress were normal, pro-inflammatory cytokine levels in CFS patients were significantly attenuated. Possible intracellular mechanisms, such as for example an enhanced sensitivity to inhibitory effects of glucocorticoids, a diminished responsivity to catecholaminergic stimulation, and a disruption of intracellular activation are discussed. Basal levels of stimulated pro-inflammatory Il-6 levels are generally related to fatigue scores. However, in CFS patients this association is of greater magnitude and can also be observed for TNF-alpha.

 

Source: Gaab J, Rohleder N, Heitz V, Engert V, Schad T, Schürmeyer TH, Ehlert U. Stress-induced changes in LPS-induced pro-inflammatory cytokine production in chronic fatigue syndrome. Psychoneuroendocrinology. 2005 Feb;30(2):188-98. http://www.ncbi.nlm.nih.gov/pubmed/15471616

 

Normal production of inflammatory cytokines in chronic fatigue and fibromyalgia syndromes determined by intracellular cytokine staining in short-term cultured blood mononuclear cells

Abstract:

It has been proposed that cytokines play a role in the pathogenesis of chronic fatigue syndrome (CFS) and fibromyalgia syndrome (FMS). However, different studies have reported conflicting results using enzyme-linked immunosorbent assay or polymerase chain reaction to detect cytokines in these conditions.

In the present study, for the first time, the production of inflammatory [interleukin (IL)-1alpha, IL-6, and TNF-alpha] and anti-inflammatory (IL-10) cytokines by CD14+ and CD14- peripheral blood mononuclear cells (PBMC) from chronic fatigue syndrome (CFS) and fibromyalgia syndrome (FMS) patients and sex- and age-matched normal subjects was investigated at the level of individual cells using the technique of intracellular cytokine staining and flow cytometry. Cultures were carried out in the presence of polymyxin B to inhibit the effect of endotoxins on cytokine production by monocytes.

The mean intensity of fluorescence (MIF) and percentage of CD14+ (monocytes) and CD14- (lymphocytes) cytokine-producing mononuclear cells were comparable in patients and controls in either unstimulated or IFN-gamma-stimulated conditions. Our study indicates that dysregulation of cytokine production by circulating monocytes or non-monocytic cells (lymphocytes) is not a dominant factor in the pathogenesis of CFS/FMS.

 

Source: Amel Kashipaz MR, Swinden D, Todd I, Powell RJ. Normal production of inflammatory cytokines in chronic fatigue and fibromyalgia syndromes determined by intracellular cytokine staining in short-term cultured blood mononuclear cells. Clin Exp Immunol. 2003 May;132(2):360-5. http://www.ncbi.nlm.nih.gov/pubmed/12699429

 

TNF-alpha and chronic fatigue syndrome

Abstract:

Based upon the clinical presentation of chronic fatigue syndrome (CFS), we hypothesized that proinflammatory cytokines may play a role in the pathogenesis of the disease. We therefore undertook a retrospective cross-sectional study to examine the role of TNF-alpha in patients with CFS. Our results suggest a significant increase serum TNF-alpha in patients with CFS (P<0.0001) compared to non-CFS controls. This study supports the further examination of the role of proinflammatory mediators in CFS. Furthermore, the clinical testing of TNF-alpha blockers and other antiinflammatory agents for the treatment of this disease is warranted.

 

Source: Moss RB, Mercandetti A, Vojdani A. TNF-alpha and chronic fatigue syndrome. J Clin Immunol. 1999 Sep;19(5):314-6. http://www.ncbi.nlm.nih.gov/pubmed/10535608

 

Serum neopterin and somatization in women with chemical intolerance, depressives, and normals

Abstract:

The symptom of intolerance to low levels of environmental chemicals (CI, chemical intolerance) is a feature of several controversial polysymptomatic conditions that overlap symptomatically with depression and somatization, i.e., chronic fatigue syndrome, fibromyalgia, multiple chemical sensitivity, and Persian Gulf syndrome. These syndromes can involve many somatic symptoms consistent with possible inflammation. Immunological or neurogenic triggering might account for such inflammation.

Serum neopterin, which has an inverse relationship with l-tryptophan availability, may offer a marker of inflammation and macrophage/monocyte activation. This study compared middle-aged women with CI (who had high levels of affective distress; n = 14), depressives without CI (n = 10), and normals (n = 11).

Groups did not differ in 4 p.m. resting levels of serum neopterin. However, the CI alone had strong positive correlations between neopterin and all of the scales measuring somatization. These preliminary findings suggest the need for additional research on biological correlates of ‘unexplained’ multiple somatic symptoms in subtypes of apparent somatizing disorders.

 

Source: Bell IR, Patarca R, Baldwin CM, Klimas NG, Schwartz GE, Hardin EE. Serum neopterin and somatization in women with chemical intolerance, depressives, and normals. Neuropsychobiology. 1998;38(1):13-8. http://www.ncbi.nlm.nih.gov/pubmed/9701717