Heterogeneity in chronic fatigue syndrome: evidence from magnetic resonance spectroscopy of muscle, 1998, Lane et al

[Andy]

Note that this is a study from 1998 and is posted for potential future reference.

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.

Paywall, https://www.nmd-journal.com/article/S0960-8966(98)00021-2/abstract

 

[Hutan]

We reported previously that a proportion of CFS patients have abnormal lactate responses to exercise at a work rate below the anaerobic threshold, and that this could not be readily explained by deconditioning or disuse 16, 17. More recently, we found that such patients have a relative deficiency of mitochondria-rich Type 1 muscle fibres compared to CFS patients with normal lactate responses [12].

In 1984, Arnold et al. [18]reported abnormal phosphorus magnetic resonance spectroscopy (MRS) findings in forearm muscles in a 30-year-old doctor who developed post-viral fatigue syndrome following varicella-zoster infection. Muscle metabolism was normal at rest but aerobic exercise induced an excessive intracellular acidosis, markedly disproportionate to phosphocreatine (PCr) depletion, and the rate of phosphocreatine regeneration post-exercise was also slowed while free [ADP], the main stimulus to mitochondrial ATP synthesis, was not increased.

These authors subsequently reported MRS findings in five further patients with similar clinical features [19]. While early excessive intracellular acidification was common, this was disproportionate to PCr depletion in only one other case. In addition, they found that such changes could be seen in a variety of other conditions, while many cases of `post-viral fatigue syndrome' had normal MRS findings. Subsequent larger studies have confirmed that there are no specific or consistent MRS changes in the majority of CFS patients 20, 21, although a significant minority of cases do show abnormalities, including more rapid exhaustion with lower end-exercise intracellular ATP concentrations than normal subjects [22], and reduced maximal rates of mitochondrial ATP synthesis 23, 24. These discrepancies suggest heterogeneity in the CFS population and the present study was designed to address this possibility.

 

[SNT Gatchaman]

In 1984, Arnold et al. [18]reported abnormal phosphorus magnetic resonance spectroscopy (MRS) findings in forearm muscles in a 30-year-old doctor who developed post-viral fatigue syndrome following varicella-zoster infection

Posted as Excessive Intracellular Acidosis Of Skeletal Muscle On Exercise In A Patient With A Post-Viral Exhaustion/Fatigue Syndrome: A 31P Nuclear Magnetic Resonance Study (1984, The Lancet)