Plasmatic oxidative stress biomarkers in multiple sclerosis: relation with clinical and demographic characteristics

In multiple sclerosis (MS) oxidative injury likely plays a major role in disease progression and in damaging tissue in the central nervous system (CNS), although with different mechanisms in the initial and the progressive disease stages. We compared the biomarker levels of plasmatic oxidative stress in patients with relapsing remitting (RR) and secondary progressive (SP) MS in order to correlate biomarker levels with demographic and clinical variables.

We included 60 consecutive MS patients (30 with RR-MS and 30 with SP-MS) and a control group of 81 healthy subjects. All patients underwent clinical assessment, including disability, fatigue and sleepiness evaluations and blood sample collection for advanced oxidation protein products (AOPPs), plasmatic ferric reducing ability (FRA) and thiol group dosage.

Plasmatic AOPPs were significantly higher while FRA and thiol levels were lower in MS patients compared to healthy controls. No difference was found in oxidative stress biomarker values in RR and SP-MS patients. However, in patients with "active" disease, FRA levels and thiol groups (expression of antioxidant power) were significantly lower. No significant correlation was found with demographic and clinical characteristics of patients, including age, disease duration, disability, fatigue, and daytime sleepiness.

Plasmatic AOPPs, FRA and thiol groups show oxidative damage and reduced antioxidant capability in MS. Although their power to characterize different courses of the disease is limited, they seem to be related to disease activity.