Erythrocytes' antioxidative capacity as a potential marker of oxidative stress intensity in neuroinflammation

The study is designed to assess the oxidative stress intensity in erythrocytes obtained from patients in different clinical phenotypes of neuroinflammation, defined as clinically isolated syndrome (CIS) and relapsing-remitting multiple sclerosis (RRMS). Advanced oxidation protein products (AOPP), malondialdehyde (MDA) and superoxide dismutase (SOD) activity were measured and compared with patients' clinical severity (expanded disability status scale-EDSS), radiological findings (gadolinium enhancement lesion volume-Gd+) and disease duration (DD). AOPP, MDA values and SOD activity were significantly higher in both study patients than in the control group (p < 0.05). While AOPP and MDA approached higher values in RRMS, compared to the CIS group (p > 0.05, p < 0.05, respectively), SOD activity showed higher values in CIS than in RRMS patients (p < 0.05). Both study patients with higher EDSS, higher number of total radiological lesions and longer DD, had higher AOPP and MDA content (p < 0.05, p > 0.05). SOD activity was lower in both study patients with higher EDSS, higher number of total radiological lesions and longer DD (p < 0.05, p > 0.05). There were positive correlations between AOPP and DD and EDSS in CIS patients (p < 0.01), and MDA levels and DD, EDSS and Gd+ in CIS, as well as with EDSS in RRMS patients (p < 0.01). There were negative correlations between SOD activity and DD and EDSS in both study patients (p < 0.01), as well as, between SOD activity and Gd+ in CIS patients (p < 0.01). The measured erythrocytes' biomarkers might represent one of the important biomarkers for the evaluation of the oxidative status of neuroinflammation and disease severity, especially in its early phase, defined as CIS.