Impaired deformability and association with density distribution of erythrocytes in patients with type 2 diabetes mellitus under treatment

BACKGROUND: Disturbed microcirculation is related to diabetic complications, and erythrocyte deformability is a critical factor regulating microcirculation. OBJECTIVES: To know the relationship between the impaired deformability and density profile in diabetic erythrocytes. METHODS: We recruited patients with type 2 diabetes (n = 15, diabetic group) and age-and sex-matched non-diabetic subjects (n = 15, control group). Erythrocyte density (ED) profile was obtained by the phthalate ester separation technique. ED distribution was fitted by sigmoidal curve, yielding specific gravity of phthalate ester allowing passage of half erythrocytes population (ED50) and slope factor. Erythrocyte deformability was estimated by our specific filtration technique. RESULTS: Diabetic group showed significantly (p < 0.001) higher HbA1c and fasting blood glucose concentration. Erythrocyte deformability in diabetic group was impaired as compared with that in control group (p < 0.001) and proportional to HbA1c (p = 0.009). However, ED50 and the slope factor in diabetic group did not differ from respective parameters in control group. CONCLUSIONS: This study demonstrated that erythrocyte deformability was impaired in diabetic patients even under treatment. HbA1c up to 7.5% is concluded not to alter the erythrocyte density but to impair the deformability, which might be a warning to clinicians for prevention of diabetic complications.