Natalizumab reduces serum pro-angiogenic activity in MS patients.

Angiogenesis has been implicated in the pathobiology of multiple sclerosis (MS). Osteopontin exerts a pro-angiogenetic effect and is increased in body fluid of MS patients. To evaluate the effect of 1 year natalizumab treatment on serum pro-angiogenic activity and on plasma osteopontin levels in relapsing (RR) MS patients. Ten RRMS patients scheduled for natalizumab treatment were enrolled and evaluated at baseline and after 1-year natalizumab treatment. Pro-angiogenic activity was assessed by a chick embryo chorioallantoic membrane assay (CAM), osteopontin levels were evaluated by an enzyme-linked immunosorbent assay. Plasma and serum samples of 10 treatment-naïve RRMS and 10 healthy controls (HCs) were used as controls of baseline evaluations. Both treatment-naïve and natalizumab scheduled RRMS patients had higher baseline vessel density (22.0 ± 3.9 and 22.5 ± 2.6, p < 0.0001) and higher osteopontin levels (65.7 ± 24.3 ng/ml and 65.9 ± 16.6 ng/ml, p = 0.019 and p = 0.029, respectively) than HCs (9.0 ± 2.2; 48.5 ± 7.8 ng/ml, respectively). Baseline osteopontin levels and vessel density were significantly correlated (rs = 0.373, p = 0.043). After 1 year of treatment, the number of vessels and the osteopontin levels, were significantly reduced (11.9 ± 2.1, p < 0.005; 49.3 ± 20.0 ng/ml, p = 0.028). Our results suggest that natalizumab could exert its anti-inflammatory properties also by inhibiting the angiogenetic mechanisms in RRMS patients.