Tu166 - Human Femoral Atheroma Exhibit Enhanced Myeloid Inflammation-resolving Potential and Reduced Inflammatory Monocyte Mobilization Compared with Human Carotid Atheroma

Joshua Slysz; Arjun Sinha; matthew DeBerge; Harris Avgousti; Shalini Singh; Shaina Alexandria; Samuel Weinberg; Donald Lloyd-Jones; Karen Ho; Jon Lomasney; Klaus Ley; Chiara Giannarelli; Edward Thorp

Abstract Text: Femoral and carotid atherosclerotic plaques differ in morphology and clinical sequelae: carotid plaques are comparatively rupture-prone and implicated in acute atherothrombotic events, whereas femoral plaques are stable and not rupture prone. However, few cellular level insights exist into immunologic features underlying these differences. We performed single-cell ribonucleic acid sequencing (scRNA-seq) on 65,920 leukocytes from freshly excised atheroma of 13 unique individuals who underwent femoral (N=9; 35265 CD45+ cells analyzed) or carotid (N=4; 30655 CD45+ cells analyzed) endarterectomy, then validated plaque niche-level findings by flow cytometry and immunohistochemistry in 36 distinct femoral or carotid endarterectomy patients. Inflammatory foam cell-like macrophages and monocytes comprised 2.5- to 4-fold higher proportions of myeloid cells in carotid versus femoral plaques, whereas anti-inflammatory foam cell-like macrophages and LYVE1-overexpressing resident-like macrophages comprised 3.5- to 9-fold higher proportions of myeloid cells in femoral versus carotid plaque (p < 0.001 for all). Metabolic gene expression scoring revealed bias toward oxidative phosphorylation in femoral plaque macrophages. Flow cytometry of plaque and blood confirmed a significant comparative excess of CCR2+ (versus CCR2-) macrophages in carotid versus femoral plaque, as well as higher CCR2 expression in classical (CD14++CD16-) monocytes in the blood of patients undergoing carotid versus femoral endarterectomy. Lymphoid-focused analyses revealed comparative B cell bias and anti-inflammatory B cell transcriptional profiles femoral versus carotid plaque, whereas CD8+ T cells comprised a higher proportion of T cells in carotid plaque. Overall, our findings in 49 unique individuals undergoing femoral or carotid endarterectomy suggest novel, translationally relevant plaque niche-specific leukocyte trafficking and differentiation cues.