The impact of oxidative stress on symptoms associated with multiple sclerosis.

Multiple sclerosis (MS) is a chronic, inflammatory and degenerative disease affecting the central nervous system, the pathophysiology of which is unknown. Oxidative stress appears to play a significant role in the initiation and the perpetuation of the inflammatory and neurodegenerative processes associated with MS. We have analysed parameters relating to oxidative stress in people with multiple sclerosis (pwMS) and in healthy individuals.Superoxide dismutase (SOD) activity was higher in pwMS than the control group. Meanwhile, total antioxidant capacity (TAC), 4-hydroxynonenal (4-HNE) and 8-hydroxy-2'-deoxyguanosine (8-OHdG) were lower in pwMS. The TAC levels correlated with age and disease duration. Regarding the relationship with disease activity, SOD levels were related to T2-FLAIR lesion burden in MRI and 8-OHdG to annualised relapse rate. PwMS with slower processing speeds exhibited lower levels of TAC and higher 4-HNE levels. No relationship was found between oxidative stress and the presence of depression, fatigue or quality of life. These results link oxidative stress to the pathogenesis of MS. Our findings suggest that these parameters might vary in function of disease activity or be related to the presence of MS-associated symptoms such as CI.