More Studies of the Deranged Myelinotrophic Factors in Multiple Sclerosis Central Nervous System Are Needed to Clarify Their Pathogenic Meaning

Many molecules (mainly growth factors and/or cytokines) are produced by human central nervous system (CNS) cells and may positively or negatively influence oligodendrogenesis, proliferation, and the migration of oligodendrocyte precursor cells (OPCs). Multiple sclerosis (MS) leads to the destruction of CNS myelin sheaths and myelin-producing oligodendrocytes (ODCs). This review considers the few published studies of platelet-derived growth factor (PDGF), nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), and ciliary-neurotrophic factor (CNTF) in cerebrospinal fluid and/or post-mortem CNS samples which, like previously reviewed studies of epidermal growth factor (EGF), have shown deranged levels in MS, and also considers the abnormal levels of Nuclear Factor kappa-light-chain-enhancer of activated B cells and some microRNAs in MS CNS. The derangements of all of these molecules in MS CNS surely hinder ODC differentiation, proliferation, and migration, and ultimately they contribute to remyelination failure. Despite the differences between MS and experimental autoimmune encephalomyelitis (EAE), it is also worth noting that the individual administration of PDGF, BDNF, CTNF, and EGF prevents the onset and/or “cures” EAE in mice, and so, together with findings concerning other aspects of MS, the results of the reviewed studies seem to support the idea that MS demyelination is a consequence of oligodendrocytopathy followed by an autoimmunity reaction.