CD13 is essential for inflammatory trafficking and infarct healing following permanent coronary artery occlusioninmice

Abstract

Aims: To determine the role of CD13 asanadhesion molecule in trafficking of inflammatory cellsto the site of injury in vivo and its function in wound healing following myocardial infarction induced by permanent coronary artery occlusion. Methods and results: Seven days post-permanent ligation, hearts from CD13 knockout (CD13KO) mice showed significant reductions in cardiac function, suggesting impaired healing in the absence of CD13. Mechanistically, CD13KO infarcts showed an increase in small, endothelial-lined luminal structures, but no increase in perfusion, arguing against an angiogenic defect in the absence of CD13. Cardiac myocytes of CD13KO mice showed normal basal contractile function, eliminating myocyte dysfunction as a mechanism of adverse remodelling. Conversely, immunohistochemical and flow cytometric analysis of CD13KO infarcts demonstrated a dramatic 65% reduction in infiltrating haematopoietic cells, including mono-cytes, macrophages, dendritic, and T cells, suggesting a critical role for CD13 adhesion in inflammatory trafficking. Accordingly, CD13KO infarcts also contained fewer myofibroblasts, consistent with attenuation of fibroblast differentiation resulting from the reduced inflammation, leading to adverse remodelling. Conclusion: In the ischaemic heart, while compensatory mechanisms apparently relieve potential angiogenic defects, CD13 is essential for proper trafficking of the inflammatory cells necessarytoprime and sustain the reparative response, thus promoting optimal post-infarction healing. © The Author 2013.