Evidence for the possible function of the fluorescent granular perithelial cells in brain as scavengers of high-molecular-weight waste products

Abstract

The fluorescent granular perithelium (FGP) of rats and humans under experimental and pathological conditions was examined with the electron microscope. The FGP incorporated high molecular-weight protein (ferritin) and carbon particles administered intraventricularly. In a case of spontaneous cerebral hemorrhage, the FGP was found to contain lipoidal products and minute fragmented cell debris. The FGP in a patient with lipidosis contained pale inclusion bodies. In aged individuals, the inclusion bodies formed irregular larger aggregates.

Involvement of specific macrophage-lineage cells surrounding arterioles in barrier and scavenger function in brain cortex.

“…2A). At higher magnification it could be seen that these cells surrounded arterioles; HRP-positive cells were rich in brownish granules and some of them were located at the bifurcation of microvessels (7,11). The granules in these cells emitted autofluorescence with the greatest intensity between 520 and 560 nm.…”

“…Morphologically, the barrier is attributed to the continuous tight junctions between endothelial cells. In addition to the existence of a barrier function of capillary endothelial cells, accumulating evidence suggests the involvement of a specific type of cell in the barrier and scavenger functions in brain blood vessels (5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17). Exogenous macromolecules injected into blood vessels or cerebral ventricles accumulated in a specific type of perivascular cell.…”

“…Collagen fibers appeared around regressing FGP/perivascular cells (Fig. 5B) (9)(10)(11)(12)(13) and identified some serological markers on their surfaces (14).…”

Growth retardation of Mato's fluorescent granular perithelial (FGP) cells in scavenger receptor knockout (SRKO) mice

“…Using light and electron microscopy and immunohistochemistry, we have been engaged in the study of a specific type of perivascular macrophage, known as Mato's fluorescent granular perithelial (FGP) cells (Mato and Ookawara, 1979;Mato et al, 1980Mato et al, , 1984Mato et al, , 1985Mato et al, , 1986Mato et al, , 1989Mato and Sakamoto, 1994;Ookawara et al, 1996). We recently demonstrated the localization of the scavenger receptor on the cytoplasmic membrane of these cells (Mato et al, 1996).…”

Localization of Lipids and Lipoprotein in Perivascular FGP Cells of Rat Cerebellar Cortex.

“…Fluorescent granular perithelial cells (FGP cells) are a type of perivascular cell with yellow autofluorescent granules in their cytoplasm and are present in the brains of many animals including humans (9)(10)(11)(12)(13)(14)(15)(16). The FGP cells are located outside blood vessels, in the space between the basal lamina of vascular smooth muscle cells and glia limitans of astrocytic processes (Virchow-Robin space).…”