Epithelial and mesothelial basement membranes in diabetic patients and dogs

The influence of diabetes on the thickness of basement membrane of the ciliary epithelium, lens epithelium, and corneal mesothelium (endothelium) was investigated post mortem in eyes from 27 human subjects and 30 dogs. Ten of the human subjects were diabetic, 10 were non-diabetic matched for age and sex, and seven were non-diabetic subjects who had been diagnosed as hypertensive 2-8 years before death. The dogs comprised three prospectively identified groups: 10 were alloxan diabetic for 5 years and kept in poor glucose control, 10 were alloxan diabetic for 5 years and kept in good glucose control, and 10 were non-diabetic animals. Basement membranes at the three sites measured appeared to be normal in the seven non-diabetic hypertensive subjects. Basement membrane of the ciliary epithelium was found to be significantly thicker than normal both in diabetic human subjects and in poorly controlled diabetic dogs. The thickness of the anterior lens capsule was significantly greater in poorly controlled diabetic dogs than in non-diabetic dogs, and showed a significant positive correlation with duration of diabetes in human subjects. Better glucose control in diabetic dogs resulted in significant inhibition of the epithelial basement membrane thickening. The basement membrane of the corneal mesothelium failed to thicken with diabetes both in human subjects and in animals.