The complement system in central nervous system diseases.
The activation of complement system is important factor in inflammatory, neurodegenerative and cerebrovascular diseases. CNS cells are able to synthesize complement components, and myelin and oligodendrocytes (OLG) are known to activate the classical pathway of complement in vitro in the absence of antibodies. Although activation of the complement system is known to promote tissue injury, recent evidence has also indicated that this process can have neuroprotective effects. In particular, terminal C5b-9 complexes enhance OLG survival both in vitro and in vivo. Complement activation may also reduce the accumulation of amyloid and degenerating neurons by promoting their clearance and suggest that certain inflammatory defense mechanisms in the brain may be beneficial in neurodegenerative disease. Complement system activation plays also an important role in brain damage after ischemic injury or head trauma. These findings strongly suggest that complement activation and membrane assembly of C5b-9 can play a role in injury but can also provide neuroprotection depending on the pathophysiological context.
Rus
Horea
H
Department of Neurology, School of Medicine, University of Maryland, Baltimore, MD 21201, USA. hrus@umaryland.edu
Cudrici
Cornelia
C
David
Stefan
S
Niculescu
Florin
F
D000818:Animals; D017209:Apoptosis / Q000276:immunology; D020274:Autoimmune Diseases of the Nervous System / Q000276:immunology*; D002545:Brain Ischemia / Q000276:immunology; D003167:Complement Activation / Q000276:immunology*; D015938:Complement Membrane Attack Complex / Q000009:adverse effects / Q000276:immunology*; D003711:Demyelinating Diseases / Q000276:immunology / Q000473:pathology; D006801:Humans; D020721:Nervous System Autoimmune Disease, Experimental / Q000276:immunology*; D019636:Neurodegenerative Diseases / Q000276:immunology; D009836:Oligodendroglia / Q000276:immunology
D015938:Complement Membrane Attack Complex