Electron-microscopic investigation of muscle mitochondria in chronic fatigue syndrome

Patients with chronic fatigue syndrome (CFS) suffer from disabling physical and mental fatigue. Abnormalities in mitochondrial function can lead to fatigue and weakness. Ultrastructural mitochondrial abnormalities have been reported to be present in CFS patients. We obtained percutaneous needle muscle biopsies from 15 CFS patients and 15 age- and sex-matched controls. We investigated previously reported ultrastructural abnormalities in CFS: subsarcolemmal mitochondrial aggregates, intermyofibrillar mitochondrial aggregates, mitochondrial circumference, area, pleomorphism and the presence of compartmentalization of the inner mitochondrial membrane. All of the steps of tissue processing, electron microscopy and data abstracting and analysis were performed in a totally blinded fashion. All of our data were rigorously quantified. We found no difference in any of these studied parameters between CFS patients and controls. Although there is no ultrastructural mitochondrial abnormality in CFS patients, other lines of evidence suggest the presence of a possible functional mitochondrial abnormality.