Inflammation

Microglia

Immune system

Cell

Central nervous system

Neuroinflammation

Gene

Neuroscience

Disease

Biology

Phenotype

Pathology

Immunology

Genetics

Medicine

Internalization

Myelin

Multiple sclerosis

Biochemistry

Acta Neuropathologica Communications

Multiple sclerosis (MS) is a chronic disease of the central nervous system characterized by massive infiltration of immune cells, demyelination, and axonal loss. Active MS lesions mainly consist of macrophages and microglia containing abundant intracellular myelin remnants. Initial studies showed that these foamy phagocytes primarily promote MS disease progression by internalizing myelin debris, presenting brain-derived autoantigens, and adopting an inflammatory phenotype. However, more recent studies indicate that phagocytes can also adopt a beneficial phenotype upon myelin internalization. In this review, we summarize and discuss the current knowledge on the spatiotemporal physiology of foamy phagocytes in MS lesions, and elaborate on extrinsic and intrinsic factors regulating their behavior. In addition, we discuss and link the physiology of myelin-containing phagocytes to that of foamy macrophages in other disorders such atherosclerosis.

The physiology of foamy phagocytes in multiple sclerosis