Abstract
It has been difficult to establish reliable biomarkers for multiple sclerosis due to the complex disease mechanisms. The pathophysiology is expressed in three main compartments: peripheral blood, the BBB, and the CNS. BDNF is a neurotrophin that potentiates proliferation of oligodendrocytes and myelination. Tau is a microtubule assembly phosphoprotein. Our purpose was to determine if serum levels of tau and BDNF could be used as severity biomarkers in multiple sclerosis. We measured total tau and BDNF by western blot and found increased tau and decreased BDNF in MS patients compared to controls. Serum total-tau has a peak in RRMS and falls to normal values in SPMS. BDNF levels were lower in all MS patients, compared to healthy controls. BDNF seems like a good biomarker for diagnosis since it always decreases in MS patients, but for our population, not for severity or progression. Tau was increased in RRMS, in the second decile of the MSSS and even in the lowest EDSS. We also found that in SPMS and the most severe cases measured by either EDSS or MSSS, tau returns to normal levels, suggesting an active role for this protein in MS.