Abstract 2048: Effects of Diabetes Mellitus and Cryopreservation on Bone Marrow Derived Endothelial Progenitor Cells
[Background] Bone marrow derived endothelial progenitor cells (EPCs) provide a therapeutic potential for angiogenesis. Applying stem cell therapy in patients will likely require large numbers of autologous EPCs. The ability to cryopreserve multiple harvests coupled with in-vitro expansion of EPCs will help achieve this goal. However, no one has evaluated the ability to preserve and expand EPCs in culture from specific populations at risk for coronary artery disease (CAD). Diabetic patients at risk for CAD could benefit from autologous EPCs transplantation, however diabetes mellitus (DM) is associated with reduced EPC function and impaired angiogenic responses. Therefore, we tested the feasibility of cryopreservation and in vitro expansion of EPCs from diabetic swine.
[Methods] Insulin dependent DM was induced in Yucatan miniswine with injection of 150 mg/kg of Alloxan for 15 weeks. Bone marrow mononuclear cells (MNCs) from iliac bone were isolated and seeded on fibronectin coated plates. Four days after culture, attached cells stained by acetylated low-density lipoprotein, lectin and DAPI were used as EPCs. EPC proliferation was assessed by measuring absorbance at 490nm (tetrazolium method). EPCs were obtained fresh from control (Con-EPC) or DM swine (DM-EPC) or obtained from cryopreserved MNC (Cryo-EPC and Cryo-DM-EPC).
[Results] The percentage of EPCs in MNCs was similar between control and DM (0.80 ±0.28 vs 0.68 ±0.20 %, p=0.73). The recovery rate of MNCs with DM had a slight trend to decrease compared to control (38.7 ± 11.6% vs 58.3 ±7.9%, p=0.21). There was no significant difference in EPC proliferation between C-EPC and DM-EPC (0.92 ±0.23 vs 0.66 ±0.10, p=0.26). In the control group, EPC proliferation was equivalent between Cryo-EPC and Con-EPC (0.92 ±0.23 vs 0.97±0.10, p=0.88). However, EPC proliferation in Cryo-DM-EPC trended to decrease compared to DM-EPC (0.66±0.10 vs 0.41±0.05, p=0.07). There was a significant decrease in proliferation of Cryo-DM-EPC compared to Cryo-EPC (0.97 ± 0.10 vs 0.41 ± 0.05, p<0.01).
[Conclusion] Cryopreservation of EPCs in DM is associated with decreased functional activity of EPCs, highlighting a challenge that needs to be overcome prior to application of autologous EPC transplantation in patients with DM.