CD117+/CXCR4+ stem cell mobilization is associated to SDF1α, IL-6 and -8 in off-pump coronary revascularization open heart surgery

Abstract

Myocardial function recovery in ischemic cardiomyopathy patients requires engraftment of hematopoietic stem cells and coronary artery bypass grafting. Bypass surgery produces an inflammatory response that probably influences bloodstream stem cell mobilization. Although off-pump coronary surgery minimizes myocardial inflammation, the surgical bypass procedure produces myocardial inflammation thus influencing myocardial regeneration. Our aim was to determine if the inflammation associated to the bypass surgical procedure favors CD117+/CXCR4+ stem cell bloodstream mobilization. Method: Ten ml blood samples of 20 patients undergoing off-pump coronary revascularization open heart surgery were obtained pre-surgery, at the sternotomy moment, during Left Internal Thoracic Artery grafting, and at sternotomy closure. 1 ml of total blood was used to quantitate CD117+/CXCR4+ cells by flow cytometry with Specific monoclonal antibodies (BioLegend), whereas the remaining blood was used to obtain serum to evaluate IL-6, 8, TNFα, and SDF1α by chemiluminescence. Results: Pre-surgery IL-6 (10.2 pg/ml) and IL8 (18.6 pg/ml) serum concentration began to increase at the moment of sternotomy and reached their peak (79.1 and 28.4 pg/ml, respectively) at sternotomy closure; the already meaningful increase of IL-6 during Left Internal Thoracic Artery grafting (32.5 pg/ml) was associated with a significantly increase in SDF1α serum concentration (199 pg/ml vs 8.6 pg/ml pre-surgery value) and CD117+/CXCR4 + cell numbers (375x103 cells/ml vs 4x103 cell/ml pre-surgery value) that diminished to 114x103 cells/ml at sternotomy closure. Conclusion: CD117+/CXCR4+ stem cell mobilization in off-pump coronary artery bypass surgery is mediated by an increase in SDF1α result of an enhanced IL-6 and IL-8 serum concentration.