Abstract
Abstract: :
Purpose: Type 2 diabetes occurs spontaneously in monkeys. The retinal changes, which are similar to changes that occur in human diabetic subjects, include large areas of nonperfusion in retina. We and others have documented an increased number of leukocytes, especially neutrophils (PMNs), in diabetic retinas and choroids. The purpose of this study was to determine the number of PMNs in retina and determine its association with diabetic retinopathy and circulating levels of lipids. Methods: Eyes were obtained from 16 diabetic and 7 nondiabetic monkeys. Four diabetic monkeys had severe retinopathy (large nonperfused areas), 5 had mild retinopathy (small nonperfused areas), and seven had no retinopathy. The retinas were incubated for ADPase (viable blood vessels) and nonspecific esterase (NSE, stains granulocytes) enzyme histochemical activity, and the number of PMNs/mm2 of retina was determined. Mean levels of total cholesterol, LDL, and triglycerides were determined just prior to the start of the animal’s final decline. Results: The number of PMNs was significantly higher in retinas of diabetic compared to nondiabetic monkeys (p = 0.035) and also significantly higher in monkeys with retinopathy versus no retinopathy (p = 0.05). PMNs were associated with aneurysms and areas of ADPase loss in capillary segments often adjacent to areas of capillary dropout. Very few PMNs appeared to have diapedesed from the retinal blood vessels. There was a significant linear correlation between the number of PMNs/mm2 and the levels of total cholesterol (R=0.907), LDL (R=0.875), and triglycerides (R=0.888). Conclusions: The number of PMNs in retina increased in diabetic retinopathy and the PMNs appear to be associated with vaso–occlusive processes. The increased numbers were associated with increased levels of circulating lipid, suggesting that lipid is perhaps associated with activation of PMNs in diabetes.
Keywords: diabetic retinopathy • vascular occlusion/vascular occlusive disease • lipids