Category: Pathophysiology

In the mind or in the brain? Scientific evidence for central sensitisation in chronic fatigue syndrome

Abstract:

BACKGROUND: Central sensitisation entails several top-down and bottom-up mechanisms, all contributing to the hyperresponsiveness of the central nervous system to a variety of inputs. In the late nineties, it was first hypothesised that chronic fatigue syndrome (CFS) is characterised by hypersensitivity of the central nervous system (i.e. central sensitisation). Since then, several studies have examined central sensitisation in patients with CFS. This study provides an overview of such studies.

MATERIALS AND METHODS: Narrative review.

RESULTS: Various studies showed generalised hyperalgesia in CFS for a variety of sensory stimuli, including electrical stimulation, mechanical pressure, heat and histamine. Various tissues are affected by generalised hyperalgesia: the skin, muscle tissue and the lungs. Generalised hyperalgesia in CFS is augmented, rather than decreased, following various types of stressors like exercise and noxious heat pain. Endogenous inhibition is not activated in response to exercise and activation of diffuse noxious inhibitory controls following noxious heat application to the skin is delayed.

CONCLUSIONS: The observation of central sensitisation in CFS is in line with our current understanding of CFS. The presence of central sensitisation in CFS corroborates with the presence of several psychological influences on the illness, the presence of infectious agents and immune dysfunctions and the dysfunctional hypothalamus-pituitary-adrenal axis as seen in these severely debilitated patients.

© 2011 The Authors. European Journal of Clinical Investigation

© 2011 Stichting European Society for Clinical Investigation Journal Foundation.

 

Source: Nijs J, Meeus M, Van Oosterwijck J, Ickmans K, Moorkens G, Hans G, De Clerck LS. In the mind or in the brain? Scientific evidence for central sensitisation in chronic fatigue syndrome. Eur J Clin Invest. 2012 Feb;42(2):203-12. doi: 10.1111/j.1365-2362.2011.02575.x. Epub 2011 Jul 27. https://www.ncbi.nlm.nih.gov/pubmed/21793823

 

Mitochondrial enzymes discriminate between mitochondrial disorders and chronic fatigue syndrome

Abstract:

We studied the extent of mitochondrial involvement in chronic fatigue syndrome (CFS) and investigated whether measurement of mitochondrial respiratory chain complex (RCC) activities discriminates between CFS and mitochondrial disorders.

Mitochondrial content was decreased in CFS compared to healthy controls, whereas RCC activities corrected for mitochondrial content were not. Conversely, mitochondrial content did not discriminate between CFS and two groups of mitochondrial disorders, whereas ATP production rate and complex I, III and IV activity did, all with higher activities in CFS. We conclude that the ATP production rate and RCC activities can reliably discriminate between mitochondrial disorders and CFS.

Copyright © 2011 Elsevier B.V. and Mitochondria Research Society. All rights reserved.

 

Source: Smits B, van den Heuvel L, Knoop H, Küsters B, Janssen A, Borm G, Bleijenberg G, Rodenburg R, van Engelen B. Mitochondrial enzymes discriminate between mitochondrial disorders and chronic fatigue syndrome. Mitochondrion. 2011 Sep;11(5):735-8. doi: 10.1016/j.mito.2011.05.005. Epub 2011 Jun 2. https://www.ncbi.nlm.nih.gov/pubmed/21664495

 

Lower whole blood glutathione peroxidase (GPX) activity in depression, but not in myalgic encephalomyelitis / chronic fatigue syndrome: another pathway that may be associated with coronary artery disease and neuroprogression in depression

Abstract:

BACKGROUND: Major depression and myalgic encephalomyelitis / chronic fatigue syndrome (ME/CFS) are two disorders accompanied by an upregulation of the inflammatory and oxidative and nitrosative (IO&NS) pathways and a decreased antioxidant status. Moreover, depression is accompanied by disorders in inflammatory and neuroprogressive (IN-PRO) pathways.

METHODS: This study examines whole blood glutathione peroxidase (GPX) in depression and in ME/CFS; GPX is an enzyme that reduces hydroperoxides by oxidizing glutathione and consequently protects the cells from oxidative damage. Blood was sampled in 39 patients with depression, 40 patients with ME/CFS and 24 normal volunteers. Whole blood was analysed for GPX activity using the Ransel assay (Randox). Severity of illness was measured by means of the Hamilton Depression Rating Scale (HDRS) and the Fibromyalgia and Chronic Fatigue Syndrome Rating Scale (FF scale).

RESULTS: We found that whole blood GPX activity was significantly (p=0.001) lower in depressed patients than in normal controls and that there were no significant differences between ME/CFS and controls. In depression and ME/CFS, there were significant and inverse relationships between GPX activity and the FF items, depressed mood and autonomic symptoms. In depression, there were significant and negative correlations between whole blood GPX and the HDRS score and autonomic symptoms.

DISCUSSION: The results show that lowered whole blood GPX activity contributes to the lowered antioxidant status in depression. Since GPX activity is a predictor of neuroprogression and coronary artery disease (CAD), lowered GPX activity in depression contributes to the IN-PRO pathways and the comorbidity between depression and CAD. Our results suggest that patients with depression would benefit from Ebselen or a supplementation with glutathione, N-Acetyl-l-Cysteine and selenium.

 

Source: Maes M, Mihaylova I, Kubera M, Uytterhoeven M, Vrydags N, Bosmans E. Lower whole blood glutathione peroxidase (GPX) activity in depression, but not in myalgic encephalomyelitis / chronic fatigue syndrome: another pathway that may be associated with coronary artery disease and neuroprogression in depression. Neuro Endocrinol Lett. 2011;32(2):133-40. https://www.ncbi.nlm.nih.gov/pubmed/21552194

Sleep-wake behavior in chronic fatigue syndrome

Abstract:

STUDY OBJECTIVES: Disturbances of the internal biological clock manifest as fatigue, poor concentration, and sleep disturbances-symptoms reminiscent of chronic fatigue syndrome (CFS) and suggestive of a role for circadian rhythm disturbance in CFS. We examined circadian patterns of activity, sleep, and cortisol secretion in patients with CFS.

DESIGN: Case-control study, 5-day behavioral observation.

SETTING: Natural setting/home environment

PARTICIPANTS: 15 patients with CFS and 15 healthy subjects of similar age, sex, body mass index (BMI), and activity levels.

INTERVENTIONS: N/A.

MEASUREMENTS: Self-report questionnaires were used to obtain medical history and demographic information and to assess health behaviors, somatic and psychological symptoms, and sleep quality. An actiwatch accelerometer recorded activity and sleep patterns over 5 days with concurrent activity and symptom logs. Diurnal salivary cortisol secretion was measured. Additionally, overnight heart rate monitoring and pain sensitivity assessment was undertaken.

RESULTS: Ratings of symptoms, disability, sleep disturbance, and pain sensitivity were greater in patients with CFS. No between-group differences were found in the pattern or amount of sleep, activity, or cortisol secretion. Afternoon activity levels significantly increased evening fatigue in patients but not control subjects. Low nocturnal heart rate variability was identified as a biological correlate of unrefreshing sleep.

CONCLUSIONS: We found no evidence of circadian rhythm disturbance in CFS. However, the role of autonomic activity in the experience of unrefreshing sleep warrants further assessment. The activity symptom-relationship modelled here is of clinical significance in the approach to activity and symptom management in the treatment of CFS.

 

Source: Rahman K, Burton A, Galbraith S, Lloyd A, Vollmer-Conna U. Sleep-wake behavior in chronic fatigue syndrome. Sleep. 2011 May 1;34(5):671-8. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3079947/ (Full article)

 

Increased plasma peroxides as a marker of oxidative stress in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS)

Abstract:

BACKGROUND: There is evidence that myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is characterized by activation of immune, inflammatory, oxidative and nitrosative stress (IO&NS) pathways. The present study was carried out in order to examine whether ME/CFS is accompanied by increased levels of plasma peroxides and serum oxidized LDL (oxLDL) antibodies, two biomarkers of oxidative stress.

MATERIAL/METHODS: Blood was collected from 56 patients with ME/CFS and 37 normal volunteers. Severity of ME/CFS was measured using the Fibromyalgia and Chronic Fatigue Syndrome (FF) Rating Scale.

RESULTS: Plasma peroxide concentrations were significantly higher in patients with ME/CFS than in normal controls. There was a trend towards significantly higher serum oxLDL antibodies in ME/CFS than in controls. Both biomarkers contributed significantly in discriminating between patients with ME/CFS and normal controls. Plasma peroxide and serum oxLDL antibody levels were both significantly related to one of the FF symptoms.

CONCLUSIONS: The results show that ME/CFS is characterized by increased oxidative stress.

 

Source: Maes M, Kubera M, Uytterhoeven M, Vrydags N, Bosmans E. Increased plasma peroxides as a marker of oxidative stress in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). Med Sci Monit. 2011 Apr;17(4):SC11-5. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3539515/ (Full article)

Migraine headaches in chronic fatigue syndrome (CFS): comparison of two prospective cross-sectional studies

Abstract:

BACKGROUND: Headaches are more frequent in Chronic Fatigue Syndrome (CFS) than healthy control (HC) subjects. The 2004 International Headache Society (IHS) criteria were used to define CFS headache phenotypes.

METHODS: Subjects in Cohort 1 (HC = 368; CFS = 203) completed questionnaires about many diverse symptoms by giving nominal (yes/no) answers. Cohort 2 (HC = 21; CFS = 67) had more focused evaluations. They scored symptom severities on 0 to 4 anchored ordinal scales, and had structured headache evaluations. All subjects had history and physical examinations; assessments for exclusion criteria; questionnaires about CFS related symptoms (0 to 4 scale), Multidimensional Fatigue Inventory (MFI) and Medical Outcome Survey Short Form 36 (MOS SF-36).

RESULTS: Demographics, trends for the number of diffuse “functional” symptoms present, and severity of CFS case designation criteria symptoms were equivalent between CFS subjects in Cohorts 1 and 2. HC had significantly fewer symptoms, lower MFI and higher SF-36 domain scores than CFS in both cohorts. Migraine headaches were found in 84%, and tension-type headaches in 81% of Cohort 2 CFS. This compared to 5% and 45%, respectively, in HC. The CFS group had migraine without aura (60%; MO; CFS+MO), with aura (24%; CFS+MA), tension headaches only (12%), or no headaches (4%). Co-morbid tension and migraine headaches were found in 67% of CFS. CFS+MA had higher severity scores than CFS+MO for the sum of scores for poor memory, dizziness, balance, and numbness (“Neuro-construct”, p = 0.002) and perceived heart rhythm disturbances, palpitations and noncardiac chest pain (“Cardio-construct”; p = 0.045, t-tests after Bonferroni corrections). CFS+MO subjects had lower pressure-induced pain thresholds (2.36 kg [1.95-2.78; 95% C.I.] n = 40) and a higher prevalence of fibromyalgia (47%; 1990 criteria) compared to HC (5.23 kg [3.95-6.52] n = 20; and 0%, respectively). Sumatriptan was beneficial for 13 out of 14 newly diagnosed CFS migraine subjects.

CONCLUSIONS: CFS subjects had higher prevalences of MO and MA than HC, suggesting that mechanisms of migraine pathogenesis such as central sensitization may contribute to CFS pathophysiology.

CLINICAL TRIAL REGISTRATION: Georgetown University IRB # 2006-481

TRIAL REGISTRATION: ClinicalTrials.gov NCT00810329 NCT00810329.

 

Source: Ravindran MK, Zheng Y, Timbol C, Merck SJ, Baraniuk JN. Migraine headaches in chronic fatigue syndrome (CFS): comparison of two prospective cross-sectional studies. BMC Neurol. 2011 Mar 5;11:30. doi: 10.1186/1471-2377-11-30. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3058027/ (Full article)

 

Nitric oxide concentrations are normal and unrelated to activity level in chronic fatigue syndrome: a case-control study

Abstract:

AIM: since patients with chronic fatigue syndrome (CFS) often present elevated levels of nitric oxide (NO) and low levels of physical activity, this study aimed at revealing possible correlations between NO concentration and physical activity.

PATIENTS AND METHODS: thirty CFS patients and 29 age- and gender-matched sedentary controls wore an accelerometer for one week and underwent venous blood sampling at the beginning and the end of the week.

RESULTS: CFS patients were significantly less active (p=0.001), but no significant differences in the amounts of NO (p=0.464 and 0.569) or interaction between NO levels and activity levels in either the CFS patients or controls were revealed.

CONCLUSION: these results provide further evidence for reduced activity levels in CFS patients, but refute there being any interaction between the amount of blood NO and activity level in both groups. The blood NO was neither predictive of, nor dependent on the activity level in CFS.

 

Source: Meeus M, VAN Eupen I, Hondequin J, DE Hauwere L, Kos D, Nijs J. Nitric oxide concentrations are normal and unrelated to activity level in chronic fatigue syndrome: a case-control study. In Vivo. 2010 Nov-Dec;24(6):865-9. https://www.ncbi.nlm.nih.gov/pubmed/21164046

 

Lipid peroxidation is elevated in female patients with chronic fatigue syndrome

Abstract:

BACKGROUND: Chronic fatigue syndrome is a debilitating disease of unclear cause and pathogenesis. It affects mostly women from lower socioeconomic classes. There is mounting evidence that oxidative stress, specifically lipid peroxidation (LPO) contributes to the disease process. We investigated levels of LPO and its possible consequences for these patients.

MATERIAL/METHODS: Forty women aged 15-45 years who fulfilled the 1994 Centers for Disease Control’s diagnostic criteria for chronic fatigue syndrome (CFS) with no comorbidities were recruited and were age matched to a control group of 40 healthy women. Levels of total cholesterol (TC), triglycerides (TG), LDL cholesterol (LDLc), HDL cholesterol (HDLc), and malondialdehyde (MDA) levels were measured.

RESULTS: Although initial statistical analyses showed no differences between groups (P=.345), when subdivided according to the level of MDA, a difference was found in the subgroup of high-level MDA (P=.034). There was a negative correlation between HDLc and MDA levels (r=0.3; P=.046), a positive correlation between TG and MDA levels (r=0.4; P=.006), and lower levels of HDL cholesterol in the CFS group (P=.036).

CONCLUSIONS: High levels of MDA, positively correlated with TG and lower HDL levels, might be indicative of proatherogenic events in female CFS patients, a group not otherwise considered a risk for atherosclerosis.

 

Source: Brkic S, Tomic S, Maric D, Novakov Mikic A, Turkulov V. Lipid peroxidation is elevated in female patients with chronic fatigue syndrome. Med Sci Monit. 2010 Dec;16(12):CR628-32. https://www.ncbi.nlm.nih.gov/pubmed/21119582

 

Gynecological history in chronic fatigue syndrome: a population-based case-control study

Abstract:

BACKGROUND: Chronic fatigue syndrome (CFS) affects disproportionately more women than men, and the condition is more common at perimenopause. We examined gynecological history events as risk factors for CFS.

METHODS: In a case-control study from a randomly selected population sample from Wichita, Kansas, 36 women with CFS and 48 nonfatigued controls, of similar age, race, and body mass index (BMI), answered a structured gynecological history questionnaire.

RESULTS: CFS cases and controls had the same mean age (51 years) and age at menarche (12 years). Overall, a greater proportion of women with CFS than controls reported pelvic pain unrelated to menstruation (22.2% vs. 1.7%, p = 0.004), endometriosis (36.1% vs. 16.7, %, p = 0.046), and periods of amenorrhea (53.9 % vs. 46.2%, p = 0.06). Compared to controls, women in the CFS group had a higher mean number of pregnancies (2.8 vs 2.0, p = 0.05) and gynecological surgeries (1.8 vs. 1.1, p = 0.05). Similar proportions of the CFS (69.4%) and control (72.9%) groups were menopausal. Although menopausal women in the CFS and control groups had similar mean age (55.5 and 55.8, respectively), menopause occurred about 4.4 years earlier in the CFS group (41.7 years vs. 46.1 years, respectively, p = 0.11). Among menopausal women, 76% of the CFS group reported hysterectomy vs. 54.6% of controls (p = 0.09), and 56% of women with CFS reported oophorectomy vs. 34.3% of controls (p = 0.11).

CONCLUSIONS: The higher prevalence of gynecological conditions and gynecological surgeries in women with CFS highlights the importance of evaluating gynecological health in these patients and the need for more research to clarify the chronologic and the pathophysiological relationships between these conditions and CFS.

 

Source: Boneva RS, Maloney EM, Lin JM, Jones JF, Wieser F, Nater UM, Heim CM, Reeves WC. Gynecological history in chronic fatigue syndrome: a population-based case-control study. J Womens Health (Larchmt). 2011 Jan;20(1):21-8. doi: 10.1089/jwh.2009.1900. Epub 2010 Nov 20. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3017420/ (Full article)

 

Gut inflammation in chronic fatigue syndrome

Abstract:

Chronic fatigue syndrome (CFS) is a debilitating disease characterized by unexplained disabling fatigue and a combination of accompanying symptoms the pathology of which is incompletely understood.

Many CFS patients complain of gut dysfunction. In fact, patients with CFS are more likely to report a previous diagnosis of irritable bowel syndrome (IBS), a common functional disorder of the gut, and experience IBS-related symptoms. Recently, evidence for interactions between the intestinal microbiota, mucosal barrier function, and the immune system have been shown to play a role in the disorder’s pathogenesis.

Studies examining the microecology of the gastrointestinal (GI) tract have identified specific microorganisms whose presence appears related to disease; in CFS, a role for altered intestinal microbiota in the pathogenesis of the disease has recently been suggested. Mucosal barrier dysfunction promoting bacterial translocation has also been observed. Finally, an altered mucosal immune system has been associated with the disease.

In this article, we discuss the interplay between these factors in CFS and how they could play a significant role in GI dysfunction by modulating the activity of the enteric nervous system, the intrinsic innervation of the gut. If an altered intestinal microbiota, mucosal barrier dysfunction, and aberrant intestinal immunity contribute to the pathogenesis of CFS, therapeutic efforts to modify gut microbiota could be a means to modulate the development and/or progression of this disorder.

For example, the administration of probiotics could alter the gut microbiota, improve mucosal barrier function, decrease pro-inflammatory cytokines, and have the potential to positively influence mood in patients where both emotional symptoms and inflammatory immune signals are elevated. Probiotics also have the potential to improve gut motility, which is dysfunctional in many CFS patients.

 

Source: Lakhan SE, Kirchgessner A. Gut inflammation in chronic fatigue syndrome. Nutr Metab (Lond). 2010 Oct 12;7:79. doi: 10.1186/1743-7075-7-79. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2964729/ (Full article)