Tag: Behan

A gene signature for post-infectious chronic fatigue syndrome

Abstract:

BACKGROUND: At present, there are no clinically reliable disease markers for chronic fatigue syndrome. DNA chip microarray technology provides a method for examining the differential expression of mRNA from a large number of genes. Our hypothesis was that a gene expression signature, generated by microarray assays, could help identify genes which are dysregulated in patients with post-infectious CFS and so help identify biomarkers for the condition.

METHODS: Human genome-wide Affymetrix GeneChip arrays (39,000 transcripts derived from 33,000 gene sequences) were used to compare the levels of gene expression in the peripheral blood mononuclear cells of male patients with post-infectious chronic fatigue (n = 8) and male healthy control subjects (n = 7).

RESULTS: Patients and healthy subjects differed significantly in the level of expression of 366 genes. Analysis of the differentially expressed genes indicated functional implications in immune modulation, oxidative stress and apoptosis. Prototype biomarkers were identified on the basis of differential levels of gene expression and possible biological significance.

CONCLUSION: Differential expression of key genes identified in this study offer an insight into the possible mechanism of chronic fatigue following infection. The representative biomarkers identified in this research appear promising as potential biomarkers for diagnosis and treatment.

 

Source: Gow JW, Hagan S, Herzyk P, Cannon C, Behan PO, Chaudhuri A. A gene signature for post-infectious chronic fatigue syndrome. BMC Med Genomics. 2009 Jun 25;2:38. doi: 10.1186/1755-8794-2-38. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2716361/ (Full article)

 

In vivo magnetic resonance spectroscopy in chronic fatigue syndrome

Abstract:

The pathogenic mechanisms of chronic fatigue syndrome (CFS) are not clearly known. Fatigue, poor short-term memory and muscle pain are the most disabling symptoms in CFS. Research data on magnetic resonance spectroscopy (MRS) of muscles and brain in CFS patients suggest a cellular metabolic abnormality in some cases.

31P MRS of skeletal muscles in a subset of patients indicate early intracellular acidosis in the exercising muscles. 1H MRS of the regional brain areas in CFS have shown increased peaks of choline derived from the cell membrane phospholipids.

Cell membrane oxidative stress may offer a common explanation for the observed MRS changes in the muscles and brain of CFS patients and this may have important therapeutic implications. As a research tool, MRS may be used as an objective outcome measure in the intervention studies. In addition, regional brain 1H MRS has the potential for wider use to substantiate a clinical diagnosis of CFS from other disorders of unexplained chronic fatigue.

 

Source: Chaudhuri A, Behan PO. In vivo magnetic resonance spectroscopy in chronic fatigue syndrome. Prostaglandins Leukot Essent Fatty Acids. 2004 Sep;71(3):181-3. http://www.ncbi.nlm.nih.gov/pubmed/15253888

 

Chronic fatigue syndrome: new evidence for a central fatigue disorder

Abstract:

Considerable evidence points towards a prominent role for central nervous system (CNS) mechanisms in the pathogenesis of chronic fatigue syndrome (CFS), a disorder characterized chiefly by persistent, often debilitating, fatigue. We wished to characterize circulating profiles of putative amino acid modulators of CNS 5-hydroxytryptamine (5-HT; serotoninergic) and dopaminergic function in CFS patients at rest, as well as during symptom-limited exercise and subsequent recovery.

Groups of 12 CFS patients and 11 age- and sex-matched sedentary controls, with similar physical activity histories, underwent ramp-incremental exercise to the limit of tolerance. Plasma amino acid concentrations, oxygen uptake and ratings of perceived exertion were measured at rest, and during exercise and recovery.

Peak oxygen uptake was significantly lower in the CFS patients compared with controls. Rating of perceived exertion in the patients was higher at all time points measured, including at rest, relative to controls. Levels of free tryptophan (free Trp), the rate-limiting 5-HT precursor, were significantly higher in CFS patients at exhaustion and during recovery, whereas concentrations of branched-chain amino acids (BCAA) and large neutral amino acids (LNAA) were lower in CFS patients at exhaustion, and for LNAA also during recovery. Consequently, the [free Trp]/[BCAA] and [free Trp]/[LNAA] ratios were significantly higher in CFS patients, except at rest.

On the other hand, levels of tyrosine, the rate-limiting dopaminergic precursor, were significantly lower at all time points in the CFS patients. The significant differences observed in a number of key putative CNS 5-HT and dopaminergic modulators, coupled with the exacerbated perception of effort, provide further evidence for a potentially significant role for CNS mechanisms in the pathogenesis of CFS.

 

Source: Georgiades E, Behan WM, Kilduff LP, Hadjicharalambous M, Mackie EE, Wilson J, Ward SA, Pitsiladis YP. Chronic fatigue syndrome: new evidence for a central fatigue disorder. Clin Sci (Lond). 2003 Aug;105(2):213-8. http://www.ncbi.nlm.nih.gov/pubmed/12708966

 

Antiviral pathway activation in patients with chronic fatigue syndrome and acute infection

Abstract:

Gene expression of key enzymes in 2 antiviral pathways (ribonuclease latent [RNase L] and RNA-regulated protein kinase [PKR]) was compared in 22 patients with chronic fatigue syndrome (CFS), 10 patients with acute gastroenteritis, and 21 healthy volunteers. Pathway activation in the group of patients with infections differed significantly from that of the other 2 groups, in whom there was no evidence of upregulation. Therefore, assay of activation is unlikely to provide the basis for a diagnostic test for CFS.

Comment in: Antiviral pathway activation in chronic fatigue syndrome and acute infection. [Clin Infect Dis. 2002]

 

Source: Gow JW, Simpson K, Behan PO, Chaudhuri A, McKay IC, Behan WM. Antiviral pathway activation in patients with chronic fatigue syndrome and acute infection. Clin Infect Dis. 2001 Dec 15;33(12):2080-1. Epub 2001 Nov 6. http://cid.oxfordjournals.org/content/33/12/2080.long (Full article)

 

The symptoms of chronic fatigue syndrome are related to abnormal ion channel function

Abstract:

The pathogenesis of chronic fatigue syndrome (CFS) is unknown but one of the most characteristic features of the illness is fluctuation in symptoms which can be induced by physical and/or mental stress. Other conditions in which fluctuating fatigue occurs are caused by abnormal ion channels in the cell membrane.

These include genetically determined channelopathies, e.g. hypokalemic periodic paralysis, episodic ataxia type 2 and acquired conditions such as neuromyotonia, myasthenic syndromes, multiple sclerosis and inflammatory demyelinating polyneuropathies.

Our hypothesis is that abnormal ion channel function underlies the symptoms of CFS and this is supported also by the finding of abnormal cardiac-thallium201 SPECT scans in CFS, similar to that found in syndrome X, another disorder of ion channels. CFS and syndrome X can have identical clinical symptoms. CFS may begin after exposure to specific toxins which are known to produce abnormal sodium ion channels.

Finally, in CFS, increased resting energy expenditure (REE) occurs, a state influenced by transmembrane ion transport. The hypothesis that ion channels are abnormal in CFS may help to explain the fluctuating fatigue and other symptoms.

Comment in:

Chronic fatigue syndrome and channelopathies. [Med Hypotheses. 2000]

Re: Letter from professors Waxman and Ptacek (Med Hypotheses 2000; 55: 457). [Med Hypotheses. 2000]

 

Source: Chaudhuri A, Watson WS, Pearn J, Behan PO. The symptoms of chronic fatigue syndrome are related to abnormal ion channel function. Med Hypotheses. 2000 Jan;54(1):59-63. http://www.ncbi.nlm.nih.gov/pubmed/10790725

 

Demonstration of delayed recovery from fatiguing exercise in chronic fatigue syndrome

Abstract:

Patients with the chronic fatigue syndrome (CFS) complain consistently of delay in recovery of peripheral muscle function after exercise. The purpose of this study was to try to confirm this observation.

A fatiguing exercise test was carried out on the quadriceps muscle group of ten patients and ten control subjects. The test consisted of 18 maximum voluntary contractions (MVCs) with a 50% duty cycle (10 s contraction, 10 s rest), and the force generated by each contraction was recorded using a KinCom dynamometer. This was followed by a recovery phase lasting 200 min in which quadriceps strength was evaluated at increasing intervals, and a follow-up session at 24 h post-exercise involving three 10 s MVCs.

Throughout the exercise period, the MVCs obtained from the control group were significantly higher than those of the patient group (P = 0.006), but both groups showed a parallel decline in force over the 18 contractions, in keeping with a similar endurance capacity.

Recovery was prolonged in the patient group, however, with a significant difference compared to initial MVCs being evident during the recovery phase after exercise (P = 0.001) and also at 24 h (P < 0.001). In contrast, the control group achieved MVCs which were not significantly different from initial values during the recovery phase, and maintained these at 24 h.

These findings support the clinical complaint of delayed recovery after exercise in patients with CFS.

Copyright 1999 Lippincott Williams & Wilkins

 

Source: Paul L, Wood L, Behan WM, Maclaren WM. Demonstration of delayed recovery from fatiguing exercise in chronic fatigue syndrome. Eur J Neurol. 1999 Jan;6(1):63-9. http://www.ncbi.nlm.nih.gov/pubmed/10209352

 

Blunted serotonin-mediated activation of the hypothalamic-pituitary-adrenal axis in chronic fatigue syndrome

Abstract:

We examined 5HT1a-mediated ACTH release in patients with chronic fatigue syndrome (CFS) using a between-subjects design. Patients attending a specialist outpatient clinic for CFS, who fulfilled CDC criteria, together with age- and sex-matched healthy comparison subjects, were recruited. Subjects had a cannula inserted in a forearm vein at 0830 h and were allowed to relax until 0900 h, when baseline bloods for ACTH and cortisol were drawn.

They were then given ipsapirone 20 mg PO and further blood for hormone estimation was taken at +30, +60, +90, +120 and +180 min. Baseline ACTH and cortisol levels did not differ between the two groups. Release of ACTH (but not cortisol) in response to ipsapirone challenge was significantly blunted in patients with CFS. We conclude that serotonergic activation of the hypothalamic-pituitary-adrenal axis is defective in CFS. This defect may be of pathophysiological significance.

 

Source: Dinan TG, Majeed T, Lavelle E, Scott LV, Berti C, Behan P. Blunted serotonin-mediated activation of the hypothalamic-pituitary-adrenal axis in chronic fatigue syndrome. Psychoneuroendocrinology. 1997 May;22(4):261-7. http://www.ncbi.nlm.nih.gov/pubmed/9226729

 

Abnormalities of carnitine metabolism in chronic fatigue syndrome

Abstract:

Carnitine may be involved in the pathogenesis of the chronic fatigue syndrome (CFS). However, no information about the cellular metabolism of carnitine in CFS patients is currently available. Therefore, we aimed to measure the levels of carnitine (total, free and short-chain) in both peripheral blood lymphocytes (PBLs) and sera from patients with CFS.

The serum levels of total, free and short-chain were comparable in CFS patients, considered as the whole group, to those in healthy control subjects, even though a trend indicating slightly reduced serum concentrations of free carnitine was observed in male patients with CFS. In contrast, the concentrations of total, free and short-chain carnitine in PBLs from patients with CFS were significantly lower than in cells from healthy controls.

Our study indicates that patients with CFS require exogenous carnitine supplementation. The low carnitine concentrations in PBLs from patients with CFS probably reflect the carnitine deficiency occurring in other tissues, including the skeletal muscles. The low cellular concentrations of carnitines may help to explain both the immunological abnormalities and the impaired energy metabolism in skeletal muscles.

 

Source: Majeed T, de Simone C, Famularo G, Marcellini S, Behan PO. Abnormalities of carnitine metabolism in chronic fatigue syndrome. Eur J Neurol. 1995 Nov;2(5):425-8. doi: 10.1111/j.1468-1331.1995.tb00151.x. http://www.ncbi.nlm.nih.gov/pubmed/24283722

 

Studies on enterovirus in patients with chronic fatigue syndrome

Abstract:

A large study on 121 patients with the chronic fatigue syndrome (CFS) that examined muscle biopsy samples for enterovirus by means of polymerase chain reaction analysis was carried out. The results were compared with those obtained from 101 muscle biopsy specimens from patients with a variety of other neuromuscular disorders (OND), including neurogenic atrophies, dystrophies, and mitochondrial, metabolic, and endocrine myopathies.

Thirty-two (26.4%) of the biopsy specimens from the group of patients with CFS were positive, compared with 20 (19.8%) from the group of patients with OND, a difference that was not significant.

This finding is in contrast to those of our previous smaller study in which significantly more patients with CFS than control subjects (53% [32 of 60] vs. 15% [6 of 41]) had enterovirus RNA sequences in their muscle. It was concluded that it is unlikely that persistent enterovirus infection plays a pathogenetic role in CFS, although an effect in initiating the disease process cannot be excluded.

 

Source: Gow JW, Behan WM, Simpson K, McGarry F, Keir S, Behan PO. Studies on enterovirus in patients with chronic fatigue syndrome. Clin Infect Dis. 1994 Jan;18 Suppl 1:S126-9. http://www.ncbi.nlm.nih.gov/pubmed/8148439

 

Serum folate and chronic fatigue syndrome

Abstract:

We assayed serum folate levels of 60 patients with chronic fatigue syndrome (CFS) and found that 50% had values below 3.0 micrograms/l. Some patients with CFS are deficient in folic acid.

Comment in: Folate and chronic fatigue syndrome. [Neurology. 1994]

 

Source: Jacobson W, Saich T, Borysiewicz LK, Behan WM, Behan PO, Wreghitt TG. Serum folate and chronic fatigue syndrome. Neurology. 1993 Dec;43(12):2645-7. http://www.ncbi.nlm.nih.gov/pubmed/8255470