Although current evidence mainly suggests immunopathogenesis of demyelination and neurodegeneration in multiple sclerosis (MS), there are results which document the importance of other factors, such as oxidative stress and its mediated injuries. The oxidative stress intensity in axonal damage during acute demyelination is little known. We performed this study as a cross-sectional biomarker validation study in order to evaluate the parameters of axonal damage (phosphorylated neurofilaments heavy chain (pNF-H)) and oxidative stress (8-hydroxy-2'-deoxyguanosine (8-OHdG)) in plasma of patients with initial and relapsing-remitting demyelination attacks, defined as clinically isolated syndrome (CIS) and relapsing-remitting multiple sclerosis (RRMS); and the correlations between these parameters and biological (index of blood brain barrier (BBB) permeability), clinical (index of disease progression), and radiological (T1-Gd-enhancing lesion volume) activities of disease. Both parameters were increased in CIS and RRMS compared to control subjects (p < 0.05). The positive correlations were observed between 8-OHdG values and index of BBB permeability, clinical severity of disease, and demyelinated brain lesion volume, in CIS group (r > 0.50; p < 0.05). Similar correlations were obtained between pNF-H values and the above parameters, as well as the index of disease progression, in RRMS group (r > 0.30; p < 0.05). There was a significant correlation between values of 8-OHdG and pNF-H only in CIS group, r = 0.52, p < 0.05. While the plasma values of 8-OHdG reflect the degree of acute demyelination in CIS, pNF-H values reflect that in RRMS. The obtained results must be reevaluated in similar prospective studies related to their prognostic values.
Keywords: 8-hydroxy-2′-deoxyguanosine; Demyelination; Neurofilament heavy chain.