Increased shear rate resistance and fastest kinetics of erythrocyte aggregation in diabetes measured with ultrasound

OBJECTIVE - To measure with ultrasound the increased erythrocyte aggregation (EA) kinetics and adhesion energy between erythrocytes in patients with type 2 diabetes and poor metabolic control. RESEARCH DESIGN AND METHODS - Blood samples were analyzed in a Couette rheometer at 32 MHz following shear rate reductions from 500 s(-1) to residual shears of 0 (stasis), 1, 2, 10, 50, 100, and 200 s(-1). The increase in EA was determined with the integrated backscatter coefficient as a function of time and shear rate. RESULTS - The time required to form aggregates was shorter in diabetic patients at shear rates below 200 s(-1) (P < 0.01). Erythrocytes formed larger aggregates in diabetic patients than in control subjects (P < 0.05 at 2 to 100 s(-1)). CONCLUSIONS - Ultrasound can potentially noninvasively demonstrate, in vivo and in situ, the impact of local abnormal EA on arteriovenous flow disorders in diabetes.