[Current questions of multiple sclerosis: the secunder progressive form of the disease]

Recent data suggest that long-term worsening is common in relapsing-remitting multiple sclerosis patients and is largely independent of relapses or new lesion formation on brain MRI. The current definition of secunder progressive multiple sclerosis is worsening of disability independent of relapses over at least 6-month interval. Early focal inflammatory disease activity and spinal cord lesion are predictors of very-long term disease outcomes in relapse - onset multiple sclerosis. The potential of PET imaging to visualize hidden inflammation in MS brain in vivo is an important contribution for better understanding the progression of the disease. Therefore, PET imaging is a promising tool in detecting the conversion from relapsing remitting multiple sclerosis to secunder progressive form of multiple sclerosis. Furthermore, neuro-axonal damage is the pathological substrate of permanent disability in different neurological disorders including multiple sclerosis. The neurofilament proteins have promise in this context because their levels rise upon neuro-axonal damage not only in the cerebrospinal fluid but also in blood. Patients with increased serum levels of neurofilament at baseline, independent of other clinical and MRI variables, experience significantly more brain and spinal cord volume loss over 2 years and 5 years of follow-up. The kynurenine-pathway abnormalities may be associated with the swich from early-mild stage multiple sclerosis to debilitating progressive forms of the disease. Analysis of these metabolites in serum may have application as multiple sclerosis disease biomarkers. Free radical action has been suggested as a causal factor in the illness. Increased free radical production and consumption of the scavenger molecules were found during the active phase of the disease. Based on the clinical findings (EXPAND Study) and pathomechanism of the disease siponimod is approved by the US Food and Drug Administration for the treatment of relapsing remitting forms of multiple sclerosis, to include secunder progressive multiple sclerosis with active disease, relapsing-remitting multiple sclerosis and clinically isolated syndrome.