title: Heterogeneity in chronic fatigue syndrome: evidence from magnetic resonance spectroscopy of muscle.
abstract: It has been shown previously that some patients with chronic fatigue syndrome show an abnormal increase in plasma lactate following a short period of moderate exercise, in the sub-anaerobic threshold exercise test (SATET). This cannot be explained satisfactorily by the effects of 'inactivity' or 'deconditioning', and patients with abnormal lactate responses to exercise (SATET +ve) have been found to have significantly fewer Type 1 muscle fibres in quadriceps biopsies than SATET -ve patients. We performed phosphorus magnetic resonance spectroscopy on forearm muscles of 10 SATET +ve patients, 9 SATET -ve patients and 13 sedentary volunteers. There were no differences in resting spectra between these groups but at the end of exercise, intracellular pH in the SATET +ve patients was significantly lower than in both the SATET -ve cases and controls (P < 0.03), and the SATET +ve patients also showed a significantly lower ATP synthesis rate during recovery (P < 0.01), indicating impaired mitochondrial oxidative phosphorylation. These observations support other evidence which indicates that chronic fatigue syndrome is a heterogeneous disorder, and confirms the view that some chronic fatigue syndrome patients have a peripheral component to their fatigue.
authors.affiliation: Division of Clinical Neuroscience and Psychological Medicine, Imperial College School of Medicine, Charing Cross Hospital, London, UK. r.lane@cxwms.ac.uk
authors.forename: R J
authors.initials: RJ
authors.lastname: Lane
authors.forename: M C
authors.initials: MC
authors.lastname: Barrett
authors.forename: D J
authors.initials: DJ
authors.lastname: Taylor
authors.forename: G J
authors.initials: GJ
authors.lastname: Kemp
authors.forename: R
authors.initials: R
authors.lastname: Lodi
mesh_terms: D000244:Adenosine Diphosphate / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000328:Adult; D001706:Biopsy; D015673:Fatigue Syndrome, Chronic / Q000175:diagnosis* / Q000378:metabolism; D005260:Female; D005542:Forearm; D014644:Genetic Variation; D006801:Humans; D019344:Lactic Acid / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000378:metabolism / Q000473:pathology*; D010725:Phosphocreatine / Q000378:metabolism; D012016:Reference Values
chemical_list: D010725:Phosphocreatine; D019344:Lactic Acid; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate