Aldose reductase in retinal mural cells.

Cultured mural cells (intramural pericytes) from adult rhesus retinal capillaries were examined for the presence of the sorbitol pathway. A radioimmunoassay for human aldose reductase, cross-reactive with rhesus lens aldose reductase, showed the presence of this enzyme in our cultured cells. Mural cells grown in culture media containing normal (10 mM) and high (40 mM) levels of glucose were examined for polyol accumulation by gas-liquid chromatography. Cells incubated in high glucose medium showed a threefold increase in sorbitol concentration over cells grown at low glucose levels. After 30 days in high glucose medium, mural cells formed dense multilayered areas with extensive cellular debris. These findings suggest the presence of the sorbitol pathway in cultured retinal mural cells and cellular degeneration in high glucose medium; this may have possible implications in the pathogenesis of diabetic retinopathy.