White matter astrocytes

Fern R. 1998. Intracellular calcium and cell death during ischemia in neonatal rat white matter astrocytes in situ. J Neurosci 18 7232-7243. 

Catalase and glutathione peroxidase provide two important cellular systems for eliminating H202. Catalase, a 56kDa cytosolic hemoprotein homotetramer that can act without a cofactor, although it may bind NAD(P)H, functions as a peroxidase to convert H202 to water. It can be irreversibly inactivated by oxidation and demonstrates decreased activity after ischemia-reperfusion. Catalase is more abundant in astrocytes than in neurons and in white matter than in gray matter, but it can be induced in neurons by neurotrophins. There is substantially less catalase activity in brain than in other tissues, such as liver. 

Figure 14.4 Different types of glial cells. Astrocytes connect capillaries and neurones. Fibrous astrocytes, with less branching and more filamentous processes, occur mainly in white matter while protoplasmic astrocytes are located principally in the grey matter. Oligodendrocytes form the myelin sheath by wrapping themselves around axons. The connection between the myelin sheath and the oligodendrocyte is permanent and provides material for the myelin sheath. Microgliocytes (microglia) are the phagocytes of the nervous system. The ciliated ependymal cells line the cavities of the central nervous system.

Histopathological features of white matter lesions include diffuse myelin pallor (sparing the U-fibers, that are supplied by cortical branches), astrocytic gliosis, widening of perivascular spaces, and loss of oligodendrocytes leading to rarefaction, spongiosis, as well as loss of myelin and axons without definite necrosis, which has also been described as incomplete white matter infarction, which may finally... 

Dietrich J, Lacagnina M, Gass D, Richfield E, Mayer-Proschel M, Noble M, Torres C, Proschel C (2005) E1F2B5 mutations compromise GFAP+ astrocyte generation in vanishing white matter leukodystrophy. Nat Med 11 277-283... 

Figure 3.4. Cellular components of the central nervous system. (A) Neurons impregnated with Golgi silver satin, (C) Calbindin immunoreactive intemeurons in the neocortex, (G) astrocytes immunoreactive with an antibody against GFAP, (H) peri-vascular astrocytes components of the BBB, (I) oligodendrocytes and white matter tracts stained with luxol fast blue, (F) ependimal cells around the periventricular zone.

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