The Effect of Vitamin D on Endothelial Progenitor Cells Function in Healthy Subjects and Patients with Diabetes Mellitus

Introduction: Endothelial progenitor cells (EPCs) are circulating bone marrow derived cells that possess the ability to differentiate into mature endothelial cells at certain target organs. Impairment of EPCs is related to endothelial dysfunction and adverse clinical outcome. Furthermore, the levels of EPC`s in patients with cardiovascular risk factors, especially diabetes mellitus (DM), are lower and their functional properties impaired. Vitamin D has multiple effects on various target organs, yet data regarding its influence on EPC`s is sparse. We hypothesized that vitamin D may improve EPC`s in both level and function.

Aim: To assess the influence of vitamin D on EPC`s level and function in diabetic patients and healthy volunteers.

Methods: Human EPCs were isolated from PMNCs of 24 Patients with DM (with HbA1C level ≥ 8%) and 13 normal healthy volunteers. EPCS were grown for 7 days on traditional fibronectin matrix with or without vitamin D. Functional properties of the cultured cells were evaluated by colony forming unit`s (CFUs) quantification and MTT viability assay. Endothelial cell lineage was confirmed by Immunostaining with antibodies directed against VEGFR-2, CD31, VE-cadherin and Tie-2.

Results: After 7 days of culture EPCs from 24 diabetic patients and 13 healthy volunteers were analyzed. In diabetic patients, EPC`s treated with vitamin D, compared to untreated cells, displayed better cellular morphology, increased colony numbers and higher number of viable cells (evaluated by MTT test ) (Figure 1). While in healthy volunteers EPCs treated with vitamin D had better functional activity and viability, there was no significant effect on colony numbers.

Conclusion: These preliminary results indicate that in-vitro vitamin D has a favorable influence on EPC`s of diabetic patients and healthy volunteers. Further investigation is required to clarify the mechanism through which vitamin D exerts its influences.