Progressive impairment of erythrocyte deformability as indicator of microangiopathy in type 2 diabetes mellitus.

The erythrocyte deformability of blood samples, of diabetes mellitus (DM) patients with and without microangiopathic complications such as nephropathy and retinopathy, is determined and is compared with that of healthy control. The erythrocyte deformability is measured in terms of elongation index (EI) with microfluidic ektacytometer, which is very sensitive to detect changes in EI of erythrocytes due to hyperglycemic process. Each measurement of diffraction pattern of erythrocyte suspension in a highly viscous polyvinyl pyrroridone (PVP) solution in a disposable microchannel is carried out. The results show that EI is well correlated with the levels of glycated hemoglobin and creatinine, as determined from the blood samples of patients. A significant decrease in the EI in DM patients compared with that in normal control is observed. In patients with complications of chronic renal failure, end stage renal disease, retinopathy and with combination of retinopathy and nephropathy, the EI is significantly decreased in comparison with that of diabetes patients without these complications. Further reduction in EI is corresponded to the changes induced by the microangiopathy process despite the maintenance of blood glucose and glycated hemoglobin by drug therapy.