Relations among Glycemic Control, Circulating Endothelial Cells, Nitric Oxide, and Flow Mediated Dilation in Patients with Type 2 Diabetes Mellitus

Objectives: Circulating endothelial cells (CEC) have been identified as a surrogate marker of endothelial dysfunction. The aim of this study was to determine the association of glycemic control with CEC and endothelial function in patients with type 2 diabetes mellitus (DM). Methods: We studied 30 patients with type 2 DM and 20 age and sex matched healthy controls (HC). Number of circulating endothelial cells was measured by flow cytometry. Endothelial function was studied by measuring flow mediated vasodilation (FMD%) in the brachial artery and serum level of nitric oxide (NO). Results: CEC count was significantly elevated in patients with DM, than HC (35.3 +/- 15.1 vs. 7.3 +/- 2.4, p < 0.001) and in patients with HbA1c > 7 than patients with HbA1c <= 7 (47.4 +/- 5.5 vs. 19.5 +/- 5.7, p < 0.001). FMD% and NO were lower in DM patients than HC (3.5 +/- 0.85 vs. 9.5 +/- 3.1, p < 0.001 and 37.8 +/- 6.1 vs. 64.1 +/- 5.7, p < 0.001 respectively). FMD% and NO were lower in patients with HbA1c > 7 as compared to patients with HA1c <= 7 (2.8 +/- 0.4 vs. 4.3 +/- 0.4, p < 0.001 and 33.1 +/- 2.9 vs. 43.9 +/- 2.8, respectively, p < 0.001). HbA1c correlated negatively with FMD% and NO levels and positively with CEC. CEC count correlated negatively with FMD% and NO. There was a significant positive correlation between CEC count and HBA1c (p < 0.001 for all correlations). Conclusion: CEC is associated with markers of endothelial dysfunction and disease control in patients with type 2 DM. These findings suggest a potential role of CEC in the pathophysiology of cardiovascular disease in type 2 diabetic and raise the importance of tight glycemic control.