The improvement of cognitive functions is associated with a decrease of plasma Osteopontin levels in Natalizumab treated relapsing multiple sclerosis

Objective: To investigate the effect of two-years Natalizumab treatment on plasma Osteopontin levels, cognitive performances and fatigue in relapsing multiple sclerosis (RRMS) patients.

Methods: Forty-nine RRMS patients scheduled for Natalizumab treatment as second-line therapy were enrolled. Plasma samples of twenty-four treatment-naïve RRMS and 22 healthy controls (HCs) were used as controls of baseline Osteopontin levels. Plasma Osteopontin levels, using an enzyme-linked immunosorbent assay, cognitive functions using the brief repeatable battery, and fatigue, by the fatigue severity scale (FSS), were assessed at baseline and every 12months. A global cognitive impairment index (CII) was calculated for each patient.

Results: Patients scheduled for Natalizumab treatment had higher baseline Osteopontin levels (mean [SD] 65.42 [22.20]ng/ml) (p=0.013) than HCs (53.20 [12.68]ng/ml), but not different from those in the treatment-naïve RRMS group (67.70 [24.23]ng/ml); 30.6% of patients showed a cognitive impairment (failure ⩾3 tests) and 47.6% complained fatigue interfering with daily activities(FSS score ⩾4.5). A significant decrease of mean Osteopontin levels (p<0.005), of mean CII values (p<0.005) and of mean FSS score (p<0.05) was found during the treatment. Baseline Osteopontin levels significantly correlated (p=0.002) with baseline CII values, and the reduction of the CII values during Natalizumab treatment significantly correlated with the decrease of the Osteopontin levels (p<0.05). No correlations were found between Osteopontin levels and FSS score before and during Natalizumab treatment.

Conclusions: Natalizumab treatment reduces plasma Osteopontin levels and improves cognition and fatigue in RRMS patients. The results suggest that the improvement of cognitive functions is associated to a decrease of plasma Osteopontin levels.