Functional and Morphological Differences of Muscle Mitochondria in Chronic Fatigue Syndrome and Post-COVID Syndrome.
Daniel Alexander Bizjak, Birgit Ohmayer, Jasmine Leonike Buhl, Elisabeth Marion Schneider, Paul Walther, Enrico Calzia, Achim Jerg, Lynn Matits, Jürgen Michael Steinacker
Author Information
Daniel Alexander Bizjak: Division of Sports and Rehabilitation Medicine, University Hospital Ulm, 89075 Ulm, Germany. ORCID
Birgit Ohmayer: Division of Sports and Rehabilitation Medicine, University Hospital Ulm, 89075 Ulm, Germany.
Jasmine Leonike Buhl: Division of Sports and Rehabilitation Medicine, University Hospital Ulm, 89075 Ulm, Germany.
Elisabeth Marion Schneider: Clinic of Anaesthesiology and Intensive Care Medicine, University Hospital Ulm, 89081 Ulm, Germany. ORCID
Paul Walther: Central Facility for Electron Microscopy, Ulm University, 89081 Ulm, Germany.
Enrico Calzia: Institute for Anaesthesiologic Pathophysiology and Process Engineering, Ulm University, 89081 Ulm, Germany. ORCID
Achim Jerg: Division of Sports and Rehabilitation Medicine, University Hospital Ulm, 89075 Ulm, Germany.
Lynn Matits: Division of Sports and Rehabilitation Medicine, University Hospital Ulm, 89075 Ulm, Germany. ORCID
Jürgen Michael Steinacker: Division of Sports and Rehabilitation Medicine, University Hospital Ulm, 89075 Ulm, Germany. ORCID
patients suffering from chronic fatigue syndrome (CFS) or Post-COVID Syndrome (PCS) exhibit a reduced physiological performance capability. Impaired Mitochondrial function and morphology may play a pivotal role. Thus, we aimed to measure the muscle Mitochondrial oxidative phosphorylation (OXPHOS) capacity and assess Mitochondrial morphology in CFS and PCSpatients in comparison to healthy controls (HCs). Mitochondrial OXPHOS capacity was measured in permeabilized muscle fibers using high-resolution respirometry. Mitochondrial morphology (subsarcolemmal/intermyofibrillar Mitochondrial form/cristae/diameter/circumference/area) and content (number and proportion/cell) were assessed via electron microscopy. Analyses included differences in OXPHOS between HC, CFS, and PCS, whereas comparisons in morphology/content were made for CFS vs. PCS. OXPHOS capacity of complex I, which was reduced in PCS compared to HC. While the subsarcolemmal area, volume/cell, diameter, and perimeter were higher in PCS vs. CFS, no difference was observed for these variables in intermyofibrillar mitochondria. Both the intermyofibrillar and subsarcolemmal cristae integrity was higher in PCS compared to CFS. Both CFS and PCS exhibit increased fatigue and impaired Mitochondrial function, but the progressed pathological morphological changes in CFS suggest structural changes due to prolonged inactivity or unknown molecular causes. Instead, the significantly lower complex I activity in PCS suggests probably direct virus-induced alterations.
