RESUMEN
Introduction: Type 2 diabetes, caused by an insulin resistant, is associated with endothelial cell dysfunction and impaired vascular homeostasis, resulting in vascular inflammation and atherosclerosis. Recently, endothelial progenitor cells (EPCs) which originated from the bone marrow are considered to be an important regulator in vascular homeostasis and a surrogate marker for vascular complications. According to this, EPC dysfunction may play an important role in causing the diabetic-associated vascular complications. Objective: To compare number and characteristic of EPCs in Type 2 diabetic patients with those of normal healthy subjects. Methods: The number of EPCs from twenty Type 2 diabetic patients and twenty healthy subjects was studied by using flow cytometry. The isolated EPCs were cultured and characterized by Dil-AcLDL engulfment. The various glucose concentrations were employed in the EPC culture in order to determine the effect of hyperglycemia on the number and viability of the EPCs. Results: The number of EPCs in Type 2 diabetic patients was significantly decreased compared to healthy subjects (5.5 \× 10⁶ \± 0.5 \× 10⁶ vs. 23 \× 10⁶ \± 2.3 x 10⁶; P \< 0.01). There was an inverse correlation between the EPC numbers and the concentrations of plasma glucose (r = -0.045) as well as HbA1c (r = -0.336). The culture of EPCs from diabetic patients took a significantly longer period of time to develop mature EPCs than control (30.8 \± 3.9 days vs. 22.4 \± 2.7 days, P \< 0.01). In addition, the number of cultured EPCs was significantly reduced when the glucose concentration in culture medium was greater than 16.5 mmol/l (P \< 0.05). These results demonstrated that glucose has a negative effect on the number and viability of EPCs in a dose-dependent fashion. Conclusion Hyperglycemic condition in Type 2 diabetes has a negative effect on the number and viability of circulating EPCs in a dose-dependent fashion.