Aim: The aim of this study was to compare the therapeutic potential of purified CD34+ cells with that of unfractioned mononuclear cells (MNCs) for the antithrombogenic property after seeding on the small caliber man-made grafts.
Methods: Unfractioned MNCs and CD34+ cells were isolated from canine bone marrow. Differentiation of CD34 cells and unfractioned MNCs into endothelial cells were examined by CD31and vWF immunohistochemistry or immunofluorescence stain, endothelial cell function were evaluated via low-density lipoprotein (ac-LDL) - DiL incorpration and in vitro angiogenesis assay. Platelet adhesion assay was performed to determine antiplatelet adhesion property of the cells in vitro. Equal number of both cells were seeded onto the luminal surface of small caliber man-made grafts and implanted to replace a segment of common carotid artery. At different time points (24 h, 72 h, and 1 week) the grafts were retrieved. HE staining and SEM exam were performed.
Results: CD34+ cells acquired significantly more CD31 and VWF expression, increased angiogenic potential and low-density lipoprotein (ac-LDL) incorporation compared to unfractioned MNCs under the induction of VEGF. More platelets were found to adhere to the surface of unfractioned MNCs group than to the CD34+ cell group. In vivo study demonstrated that more platelet adhesion and thrombus formation were observed in the unfractioned MNCs group rather than the CD34+ group. All the grafts in both groups were patent after implantation, except one graft seeded with unfractioned MNCs, occluded at 1 week. Statistically lower ratio of thrombi was found in the CD34+ cell seeding group at 24 h and 1 week after implantation, compared with the unfractioned MNCs one (P<0.05).
Conclusion: CD34+ cell exerted better antithrombogenic property than unfractioned MNCs after seeding onto the small caliber vessel grafts.