Vitamin B12 as a neuroprotectant in neuroinflammation

Neuroinflammation comprises an orchestrated cascade of cellular and molecular processes triggered in response to insults and aiming at protecting the central nervous system. The main agent of this response is the microglia, but astrocytes, neurons, oligodendrocytes, vascular pericytes, and infiltrated peripheral immune cells are also involved. Paradoxically, imbalanced and uncontrolled neuroinflammation is recognized as a major feature of neuropsychiatric disorders. B12 (cobalamin) vitamers, besides being key players in the energy metabolism and the sulfur amino acids pathway, also attenuate neuroinflammation by acting in various underlying and interconnected processes such as scavenging reactive species, maintaining adequate levels of H2S, preventing some harmful effects of excess homocysteine, and decreasing NMDA receptor-mediated excitotoxicity in central nervous system cells. B12 also modulates different chromatin remodeling mechanisms that can downregulate some pivotal genes in neuroinflammation. This pleiotropic mode of action in the control of various components of neuroinflammation makes B12 one of the most promising nutrients for neuroprotection in many neuropsychiatric disorders.