Mitochondrial activity is impaired in lymphocytes of MS patients in correlation with disease severity

Background: Multiple sclerosis (MS) is a multifactorial disease of the central nervous system in young adults. Mitochondrial respiration provides fuel necessary for cellular function and is especially important in cells with large energy demand including neurons. Various studies suggest that the pathogenesis of MS may be associated with mitochondrial dysfunction. Methods: We examined 145 volunteers including 62 MS patients and healthy controls. MS patients were divided into two groups according to their disease severity: those with mild disability (EDSS=0–3.0) and those with moderate-severe MS (EDSS=3.5–8). After signing an informed consent, blood was taken and was separated to platelets and lymphocytes. Mitochondria activity was monitored as mitochondrial transmembrane potential following staining with JC1 dye in platelets and lymphocytes utilizing flow cytometry. Results: We examined mitochondria activity as JC1 values from all separated lymphocyte samples and found significantly higher levels of mitochondrial activity in lymphocytes separated from healthy controls vs. MS patients (mean of 87.9% vs. 75.6%, p = 0.001). Significant differences in mitochondrial activity were also found when comparing means of groups divided according to MS disease severity. Interestingly, there were no significant differences in mitochondrial activity between patients treated with diverse medications or untreated patients. Mitochondrial activity was also examined in platelets, but no significant differences were found between groups. Conclusions: Results obtained here show that mitochondrial activity was significantly lower in MS patients in comparison to healthy controls. In addition, there was a significant difference in mitochondrial activity depending on MS degree of disability. These initial findings in a peripheral examination hold potential for new diagnostic biomarkers to be considered in the future.