The Chronic Fatigue Syndrome, Mitochondrial Dysfunction and Monocyte Differentiation

The Chronic Fatigue Syndrome (CFS), also known as Myalgic Encephalomyelitis(ME), is a complex, multisystem disorder characterized by persistent fatigue and a wide range of symptoms as well as post-exertional malaise(PEM).CFS is observed in an estimated 50% of Long COVID patients. While the cause of CFS remains unclear, it is hypothesized to develop after viral infections such as EBV. Mitochondrial dysfunction and immune dysregulation are strongly implicated. In this study, we investigated mitochondrial dysfunction and monocyte differentiation in CFS. For the mitochondrial research we used cultured HUVECs treated with patient-derived serum, healthy serum, and untreated media controls, with and without the addition of K21,all cultured in triplicate. Mitochondrial morphology was assessed via fluorescence microscopy using GFP staining to visualize the mitochondria, while protein expression (p53,MFN1,DRP1andLONP1) was analyzed by Western blots. Microscopy revealed mitochondrial fragmentation in CFS-treated cultures. Western blot analysis showed significant differences in mitochondrial protein expres sion comparing CFS treated samples to healthy controls, however not all the data is consistent with visual observations. This suggests protein concentrations and therefore mitochondrial func tioning are affected but more research is required. To assess immune dysfunction, we cultured monocytes, treated with patient and healthy serum and controls with untreated media. Mono cyteifferentiation was evaluated using ELISA to detect markers of M1 (IL-12) and M2 (IL-10) macrophages. Results showed high intra-patient variability, suggesting the need for additional replicates and patient samples to reach statistical significance. These findings support the hypoth esis of mitochondrial impairment in CFS and provide a basis for future references into monocyte polarization as a contributing factor to chronic inflammation in this condition.