Correlation between Circulating Endothelial Progenitor Cell Markers, Vitamin D, and Iron Levels in Diabetic Nephropathy

Objective: Circulating endothelial progenitor cells (EPCs) play an essential role in endothelial repair and neovascularization. Vitamin D deficiency may contribute to EPC depletion and endothelial dysfunction in patients with type 2 diabetes. In addition, iron overload is closely related to the development of diabetes and its various chronic complications. This study was designed to determine the relationship between EPC markers (CD34, CD133), vitamin D, and iron in patients with diabetic nephropathy. Materials and Methods: This case-control study was conducted on 67 diabetic patients with or without nephropathy. Blood pressure and all biochemical parameters were measured and compared. Serum concentrations of insulin, vitamin D, CD34, and CD133 were measured using ELISA. Serum iron concentration was measured using atomic absorption spectrometry. Results: Body mass index (P= 0.006), diastolic pressure (P= 0.018), insulin level (P= 0.028), Creatinine (P= 0.013), duration of diabetes, uric acid, and glomerular filtration rate (GFR) were significantly different between the two groups (each P= 0.0001).The vitamin D (P= 0.034), CD34 (P= 0.0001), and CD133 (P= 0.025) levels decreased, and Iron (P= 0.0001) increased in the case group. Also, CD34 has a significant direct relationship with insulin, insulin resistance, and CD133. The results showed that vitamin D, iron, CD34, and CD133 had a significant relationship with the severity of nephropathy (P= 0.0001, each). Conclusion: Increased iron levels and decreased vitamin D, CD34, and CD133 levels are associated with the severity of nephropathy. This result indicates that diabetic nephropathy may directly reduce CD34 and CD133 levels in the body, increasing the incidence of secondary complications in these patients.