Microsurgical Isolation and Molecular Characterization of the Mouse Left Internal Mammary Artery: Insights into Natural Resistance to Atherosclerosis

Atherosclerosis develops unevenly across the vascular tree, yet the molecular basis for this regional susceptibility remains poorly defined. The left internal mammary artery (LIMA), the most durable conduit for coronary artery bypass (CABG) surgery, is uniquely resistant to atherosclerosis in humans; however, it has never been isolated or studied in mouse models, limiting mechanistic insight into atheroprotective pathways. Here, we establish the first method to identify and isolate the murine LIMA and generate the first transcriptomic atlas of this artery. Cross-species analyses of human and mouse LIMA reveal a conserved protective signature that distinguishes the LIMA from atheroprone vessels and uncover fundamental molecular differences that govern vascular resilience. This study presents a transformative experimental platform for dissecting the determinants of atheroprotection and identifying molecular targets to improve CABG graft performance and long-term cardiovascular outcomes.