Effects of off-pump versus on-pump coronary artery bypass grafting on function and viability of circulating endothelial progenitor cells
Marc Ruel1, Erik J Suuronen, Jianming Song
1Division of Cardiac Surgery, University of Ottawa, Ottawa, Ontario, Canada. mruel@ottawaheart.ca
Insights
Off-pump coronary artery bypass grafting preserves endothelial progenitor cell function and viability, unlike on-pump surgery. This study highlights potential benefits of off-pump procedures for vascular repair cells.
Area of Science:
- Cardiovascular Surgery
- Regenerative Medicine
- Vascular Biology
Background:
- Off-pump coronary artery bypass grafting (CABG) may reduce complications compared to on-pump CABG.
- Aortic manipulation differences are suspected, but systemic endothelial progenitor cell (EPC) responses are unexamined.
Purpose of the Study:
- To investigate and compare EPC characteristics after off-pump versus on-pump CABG.
Main Methods:
- Prospective enrollment of 20 patients undergoing either off-pump or on-pump CABG.
- Isolation and culture of peripheral blood EPCs pre- and post-surgery.
- Analysis of EPC number, phenotype, proliferation, migration, and viability.
Main Results:
- EPC phenotype and proliferation were similar between groups.
- EPC migratory function was significantly higher post-off-pump CABG (P=.04).
- Postoperative EPC viability was preserved after off-pump CABG but reduced after on-pump CABG (P=.01).
Conclusions:
- Both CABG types mobilize EPCs, but on-pump surgery impairs their migratory function and viability.
- Off-pump CABG preserves EPC function and viability, suggesting a potential advantage for vascular repair.
- Further research is needed to link EPC function/viability to clinical outcomes and therapeutic potential.
Objective:
Off-pump coronary artery bypass grafting may result in fewer myocardial and vascular complications than on-pump. Although differences in aortic manipulations likely play a role, the systemic responses of endothelial progenitor cells to both types of operations have not been examined. We sought to examine endothelial progenitor cell characteristics after off-pump versus on-pump coronary artery bypass grafting.
Methods:
Twenty patients undergoing off-pump or on-pump coronary artery bypass grafting were prospectively enrolled and had endothelial progenitor cells isolated and cultured from their peripheral blood before and 24 hours after surgery. Endothelial progenitor cells were identified by fluorescent dual lectin/low-density lipoprotein binding. Their number, phenotype characteristics, proliferation, migratory function, and viability were determined in a blinded fashion.
Results:
Patient characteristics and numbers of grafts were equivalent. Endothelial progenitor cells had similar phenotypes between groups before and after surgery. Off-pump and on-pump coronary artery bypass grafting resulted in similar increases in endothelial progenitor cell numbers and showed equivalent proliferation activity. However, endothelial progenitor cell migratory function was higher in off-pump patients (25.3 +/- 5.0 vs 5.0 +/- 1.0 cells per high-powered field for off-pump vs on-pump coronary artery bypass grafting, respectively; P = .04). Postoperative endothelial progenitor cell viability adjusted for preoperative baseline was also higher after off-pump than on-pump coronary artery bypass grafting by 72.4% +/- 14.6% (P = .01). Endothelial progenitor cells of on-pump patients were less viable after surgery than before surgery, whereas the reverse was observed in off-pump patients.
Conclusions:
Both on-pump and off-pump coronary artery bypass grafting elicit mobilization of endothelial progenitor cells into the peripheral blood. On-pump coronary artery bypass grafting, however, impairs the migratory function and viability of these vascular repair cells, which are conversely preserved after off-pump surgery. Further work is necessary to determine whether the function and viability of endothelial progenitor cells correlate with vascular outcomes and whether their therapeutic modulation may one day benefit coronary artery bypass grafting patients.
