Increase of acidic fibroblast growth factor in the brains of hamsters infected with either 263K or 139H strains of scrapie

Ependymal cells: biology and pathology

The literature was reviewed to summarize the current understanding of the role of ciliated ependymal cells in the mammalian brain. Previous reviews were summarized. Publications from the past 10 years highlight interactions between ependymal cells and the subventricular zone and the possible role of restricted ependymal populations in neurogenesis. Ependymal cells provide trophic support and possibly metabolic support for progenitor cells. Channel proteins such as aquaporins may be important for determining water fluxes at the ventricle wall. The junctional and anchoring proteins are now fairly well understood, as are proteins related to cilia function. Defects in ependymal adhesion and cilia function can cause hydrocephalus through several different mechanisms, one possibility being loss of patency of the cerebral aqueduct. Ependymal cells are susceptible to infection by a wide range of common viruses; while they may act as a line of first defense, they eventually succumb to repeated attacks in long-lived organisms. Ciliated ependymal cells are almost certainly important during brain development. However, the widespread absence of ependymal cells from the adult human lateral ventricles suggests that they may have only regionally restricted value in the mature brain of large size.

Increased expression of the embryonic intermediate filament, nestin, in the brains of scrapie-infected mice

This study investigated the immunohistochemical localization of nestin and its expression level in the brains of mice infected with scrapie, a disease which is characterized by spongiform neurodegeneration, neuronal vacuolation, and astrogliosis. Western blot analysis showed that the protein level of nestin was significantly increased in scrapie-infected brains compared with those of control brains. Nestin immunoreactivity in vascular endothelial cells was more intense in the brains of scrapie-infected mice compared with those of controls. There was marked nestin immunostaining in reactive astrocytes, but not in the neurons of the scrapie-infected brains. Considering all the findings, this study suggests that the nestin-positive cells, including glial cells and vascular endothelial cells, may have the potential to differentiate into mature glial cells and other neuronal elements, which would replenish lost neurons.