Increased adhesion of erythrocytes to endothelial cells in diabetes mellitus and its relation to vascular complications.

We studied the adhesion of erythrocytes from 30 diabetic patients and 25 controls to human endothelial cells. Washed erythrocytes were labeled with 51Cr and added to confluent endothelial cells cultured from umbilical veins. After incubation at 37 degrees C, the nonadherent erythrocytes were removed by sequential washings. The percentage of erythrocytes adhering to cultured endothelium after each wash was significantly higher when erythrocytes were from diabetics than when they were from controls (P less than 0.005). After the fifth wash, the mean adhesion ratio (percentage of adhering diabetic red cells: percentage of adhering control red cells) was 2.33 (range, 0.8 to 5.2). Increased adhesion was related to the extent of vascular complications in the diabetics, as assessed by a vascular score. With the same technique, fewer erythrocytes adhered to plastic and to cultured human fibroblasts than to endothelial cells, although the adhesion of the diabetic red cells to these surfaces was higher than that of the controls. These results suggest that in diabetes there is an intrinsic erythrocyte abnormality that is related to vascular disease.