Abstract 13606: Cardiac Fibroblast Derived Matrix-educated Macrophages Express VEGF and IL-6, and Recruit Mesenchymal Stromal Cells

Abstract

Introduction: Polarizing monocytes into macrophages that possess anti-inflammatory and angiogenic properties could be cardio-reparative following myocardial infarction. Co-culturing cardiac fibroblasts (CF) with monocytes is observed to lead to alternatively activated macrophages. We previously showed that CF produce a unique cardiac matrix (CX) that is fibronectin enriched. Whether decellularized CX can drive differentiation of monocytes to macrophages with angiogenic and anti-inflammatory properties is unknown. Hypotheses: (i) CX educated macrophages (CXMq) that secrete VEGF and IL-6, which have known angiogenic and anti-inflammatory properties respectively, (ii) CXMq can recruit mesenchymal stromal cells (MSC), which have known anti-inflammatory properties and (iii) fibronectin is responsible for this effect. Methods: Human monocytes (CD14 + ) were cultured on CX, plastic and gelatin. After 3 days, flow expression of the macrophage markers CD14, CD16, CD163, CD206, PDL1, CD86, and HLA-DR was measured. VEGF and IL-6 levels were measured from the spent media. A transwell migration assay was performed by placing monocytes on CX in the lower chamber and MSC in the upper chamber. CX was enzymatically dispersed and flow cytometry was performed for CD14 (macrophage marker) and CD73 (MSC marker). Migration was defined as the % of MSCs reaching the lower chamber (see Figure). Controls included monocytes plated on plastic, and monocyte/CX combination cultured with and without fibronectin integrin receptor inhibitor. Results: CXMq secreted high levels of VEGF and IL-6 and also had low expression of inflammatory markers CD16, CD86, HLADR. Further, CXMq recruited MSC more robustly than monocytes and CX alone (see Figure). Selective fibronectin integrin receptor blockade prevented MSC recruitment (*p<0.05). Conclusions: CXMq has anti-inflammatory and pro-angiogenic properties that is potentially mediated by fibronectin.