Affiliations: [a] Department of Physiology and Biophysics, University of Southern California, School of Medicine, Los Angeles, CA 90033, USA | [b] Department of Medicine, Section of Diabetes/Clinical Nutrition, University of Southern California, School of Medicine, Los Angeles, CA 90033, USA
Note: [] Accepted by: Editor G.D.O. Lowe
Abstract: RBC aggregation indices and blood viscoelasticity, at a hematocrit of 40%, were determined in 40 poorly controlled, hyperglycemic (serum glucose ≥ 21 mmol/l) Type 2 (NIDDM) diabetic patients and in 40 age-matched control subjects. Aggregation parameters were measured by a Myrenne Aggregometer and by the Zeta Sedimentation Ratio, and viscoelasticity via an OCRD viscometer. Compared to the control subjects, the patient data indicated: 1) a faster rate of RBC aggregation at stasis (33%, p<0.001); 2) higher shear rates (45%, p<0.001) and shear stresses (77%, p<0.001) for dispersion of RBC aggregates; 3) enhanced RBC aggregation at 10 s−1 (9%, p<0.001); 4) an elevated Zeta Sedimentation Ratio (19%, p<0.001); 5) higher viscous and elastic components of the complex viscosity (at 10 s−1, 7% for viscous and 30% for elastic, p<0.005). Plasma fibrinogen levels (N=16) were significantly greater than control (46%, p<0.005) and correlated with the Zeta Sedimentation Ratio (p<) and the rate of aggregation (p<0.01). However, neither serum glucose, percent HbA1 for a 12 patient subgroup, nor duration of the disease were found to significantly (p>0.2) influence either any of the aggregation indices or the two viscoelastic components. Correlations between blood viscoelasticity and the aggregation parameters could be demonstrated and the specific measures of RBC aggregation also exhibited cross correlations. Our results show that both RBC aggregation and blood viscoelasticity are markedly abnormal in hyperglycemic Type 2 diabetics and suggest that altered in vivo blood flow dynamics should be present in these individuals.
