Interleukin-3 is required for thoracic aneurysm and dissection in a mouse model.

The pathogenesis of thoracic aortic aneurysm and dissection (TAAD) is complex and incompletely understood. The hallmarks of the disease process are aortic inflammatory cell infiltration and protease mediated elastic fiber disruption. In a study recently published in Clinical Science (2018) 132 (6), 655-668), Liu et al. explore the mechanism through which aortic vascular smooth cells and macrophages participate in TAAD using a mouse model. The authors propose that interleukin-3 (IL-3) released from aortic vascular smooth cells is central to the disease process. IL-3 stimulated matrixmetalloproteinase 12 (MMP12) release from macrophages via mitogen activated protein kinase pathways. MMP12 is a protease known to be involved in both aortic aneurysm and dissection. IL-3 knockout mice had significantly reduced aortic wall MMP12, and reduced protease activity. This was associated with protection against TAAD.