Quantitative analysis of retinal vessel changes in galactose-fed dogs

Retinal vessel changes in 36-month 30% galactose-fed beagles treated with or without aldose reductase inhibitors were quantified using an Olympus Cue-3 color image analysis system. Individual maps of the intact retinal vasculature, isolated by trypsin-digestion, were divided into 24 distinct subregions and measurements of either the endothelial cell to pericyte (E/P) ratio or cell densities, expressed as pericytes per mm capillary length or endothelial cells per mm capillary length, were conducted in 0.1 mm2 areas surrounding the midpoints of 12 subregions associated with the highest incidence of microaneurysms. Significantly increased E/P ratios and decreased pericyte densities were observed with the duration of galactose-feeding. These retinal changes were reduced by aldose reductase inhibitor treatment. Correlations between the E/P ratio and either number of microaneurysms or cataract severity were also observed. These data support the dose-dependent effects of aldose reductase inhibitors in preventing pericyte degeneration and subsequent formation of microaneurysms (Archives Ophthalmol. 108:1301, 1990).