Capillary lesions develop in retina rather than cerebral cortex in diabetes and experimental galactosemia
T. S. Kern and R. L. Engerman
Department of Ophthalmology and Visual Science, University of Wisconsin, Madison, 53706-1532, USA.
OBJECTIVE: To isolate microvessels from cerebral cortex of dogs with
alloxan-induced diabetes and dogs with experimental galactosemia to compare
the prevalence of microvascular lesions in cerebral cortex with that in
retina. METHODS: Microvessels were isolated from cerebral cortex of
experimental animals using a sieving method, and compared with the retinal
vasculature isolated from the same animals using the trypsin digestion
method. RESULTS: Dogs with diabetes or experimental galactosemia of 5
years' duration had retinopathy that was morphologically indistinguishable
from that of humans with diabetes, including microaneurysms, acellular
capillaries, and pericyte ghosts. These lesions never were seen in cerebral
cortical vessels of the same animals. The only morphologic abnormality
observed in cerebral capillaries of dogs with diabetes and dogs fed
galactose was thickening of basement membrane. CONCLUSIONS: Local
influences in the eye apparently play an important role in the development
of diabetic retinopathy. Current hypotheses about the pathogenesis of the
retinopathy do not account adequately for such differences in the tissue
distribution of vascular lesions.
