Abstract 14624: Delivery of Osteocalcin (OCN+) Expressing Myeloid Cells is Sufficient to Generate Vascular Calcification
Introduction: Recent data have suggested that a distinct subpopulation of myeloid cells expressing osteocalcin (OCN) and bone alkaline phosphatase (BAP) has procalcific activity. In this study we directly tested the hypothesis that peripheral blood-derived human myeloid cells that co-express CD14 and OCN are capable of mineralization in a murine carotid artery delivery model.
Methods: Blood was obtained from normal human donors and peripheral blood mononuclear cells were isolated by Ficoll density centrifugation. Fluorescence-activated cell sorting was used to fractionate the peripheral blood-derived human myeloid cells into CD14+OCN+ and CD14+OCN- subpopulations. 3x105 cells were resuspended in MatrigelTM and injected periadventitialy via an open surgical approach to the left carotid artery of 4-6 month old male NOD-scid IL2Rgammanull mice (n=5 for each cell group). As an internal control, an equal volume of MatrigelTM without cells was injected around the right carotid artery. An additional control group consisted of 5 mice which did not undergo surgery. Carotid arteries were harvested after twelve weeks for histological evaluation by hematoxylin and eosin and von Kossa staining. Fluorescence in situ hybridization (FISH) was also performed to investigate for the presence of donor human cells.
Results: Positive von Kossa staining was identified in the periadventitial region of the left carotid artery in all mice that received CD14+OCN+ cells as compared to 2/5 (40%) recipients of CD14+OCN- cells and none of the mice in the no surgery control group (p<0.01). Only 1/5 (20%) of the right carotid artery specimens (MatrigelTM only) demonstrated evidence of mineralization in the CD14+OCN+ group (p<0.05). Donor human cells were identified in the periadventitium of left carotid specimens twelve weeks after implantation.
Conclusions: Expression of OCN by human blood derived CD14+ myeloid cells increases their capacity to form mineral in a perivascular milieu. The current study may support the contribution of OCN+ myeloid cells in calcific vascular disease.
- © 2012 by American Heart Association, Inc.