Abstract
Purpose: :
Diabetic retinopathy is caused by capillary occlusions. Monocytes–derived microparticles (MDMPs) are released from activated monocytes and enhance the procoagulant activity, and also activate adhesion reactions. These are key events in the development of capillary occlusion. However, the correlation between the levels of MDMPs and diabetic retinopathy has not been precisely determined.The purpose of this study was to determine whether the microangiopathic changes in the retina arise from the increased level of MDMPs.
Methods: :
A total of 72 type 2 diabetic patients were studied. The stage of diabetic retinopathy was determined by ophthalmoscopy and fluorescein angiography. The MDMPs levels in the blood, and the levels of platelet activation markers (platelet–derived microparticles; PDMPs, CD62P, and CD63) were measured by flow cytometry. The plasma levels of ICAM–1 and P–selectin were analyzed by ELISA. The level of HbA1c was determined by standard laboratory procedures.
Results: :
The level of MDMPs was significantly correlated with the levels of PDMPs (r =0.52, P< 0.001), CD62P (r =0.37, P =0.001), CD63 (r =0.31 and P =0.007), P–selectin (r =0.38, P =0.001), and ICAM–1 (r =0.31, P =0.009). The MDMPs level increased with the progression of the diabetic retinopathy; 81 ± 14/104 plt in patients without retinopathy (n =10); 88 ± 8/104 plt with mild or moderate non–proliferative diabetic retinopahy (NPDR, n=12); 95 ± 8/104 plt with severe NPDR (n =24); and 112 ± 9/104 plt with PDR (n =26). The MDMPs level in patients with areas of capillary occlusion (123 ± 10/104 plt, n =25) was significantly higher than that in patients without areas of capillary occlusion (84 ± 5/104 plt, n =25; P=0.0008).
Conclusions: :
There was a tendency for an increase in the MDMPs levels according to the stage of diabetic retinopathy, and the significantly higher levels of MDMPs were detected in diabetic retinopathy with non–perfused areas. This would suggest that the high levels of MDMPs may accelerate the progression of diabetic retinopathy and may be a prognostic factor for diabetic retinopathy.
Keywords: diabetic retinopathy • diabetes • vascular occlusion/vascular occlusive disease