Polaryzacja mikrogleju i makrofagów w wybranych chorobach degeneracyjnych i zapalnych układu nerwowego

Macrophages are effector immune cells that have an ability to undergo polarization, i.e. a change in phenotype and their activity. Therefore, two major types of macrophages have been distinguished: classically polarized (M1) macrophages, which play a role in host defense and which have proinflammatory activity and alternatively polarized (M2) macrophages, which have a regulatory role and promote tissue regeneration. Macrophages can be found in almost all tissues of the body and thus polarization influences various processes. In the central nervous system, tissue macrophages (microglia) can be found; however, in many pathological situations macrophages can also be recruited from blood-circulating monocytes. Neurodegenerative diseases, injuries and especially autoimmune diseases are often associated with the immune system response. This response can exert significant effects on the course of the disease and/or tissue regeneration. The topic of macrophage polarization is interesting because activity of M1 and M2 cells differently affect neuronal and oligodendrocyte survival, axon growth, demyelination and remyelination processes and the blood–brain barrier permeability. This is due to differences in the production of reactive oxygen species and nitric oxide, cytokine and growth factor secretion, direct cell-to-cell communication and abilities to phagocyte. In this paper the topic was discussed in the context of stroke, spinal cord injury, Alzheimer’s disease, amyotrophic lateral sclerosis and multiple sclerosis. In many of these pathologies, a certain temporal or spatial gradient of microglia/macrophage phenotypes is observed. Therefore, it is likely that changes of macrophage polarization can potentially promote tissue regeneration and hinder neurodegenerative diseases.