Evaluation of total, ceruloplasmin-associated and type II ferroxidase activities in serum and cerebrospinal fluid of multiple sclerosis patients

Multiple sclerosis (MS) patients have increased brain iron deposition with higher oxidative stress (OxS). These two features can be caused by an inefficient removal of free iron from extracellular compartment. Ferroxidase activity (Feox) exerted by ceruloplasmin (FeoxCp) and by other molecules (FeoxII) appears to have a central role in this process. The aim of this study was to investigate serum and cerebrospinal fluid (CSF) total Feox, FeoxII and FeoxCp activities in MS patients and neurological controls. Serum and CSF Feox activity, FeoxII and FeoxCp activity was measured in 91 relapsing-remitting (RR) MS patients, 79 subjects with other inflammatory neurological disorders (OIND) and 65 with non-inflammatory neurological disorders (NIND), as controls. This study was approved by the Local Committee for Medical Ethics in Research. Serum total Feox activity was lower in MS group than in both NIND and OIND, with only the former control group differing significantly (p<0.001); FeoxII and FeoxCp activities were comparable among the groups. Serum Feox activities were not associated with disease activity as assessed by clinical examination or by Magnetic Resonance Imaging (MRI). Only total Feox activity was detectable in the CSF and was not different in MS compared to either OIND or NIND. In conclusion, a condition of low systemic Feox may increase the susceptibility of MS patients to iron(II) mediated-oxidative damage. This alteration is not reflected in CSF, suggesting that agents endowed with Feox activity might have different impact in iron homeostasis in the central nervous system compared to periphery.