Abstract 1045: Using Multiplex Imaging For Cell Phenotyping Of Early Human Atherosclerosis

Abstract

Background: In the past few years, animal models and cultured cells have shown that smooth muscle cells (SMCs) and inflammatory cytokines are important new players in atherosclerotic disease. Validating the roles of these new players in human atherogenesis is crucial for the development of therapeutics targeting them. Multiplex imaging is a powerful tool for mapping cell phenotypes and microenvironment in tissue sections, enabling proof-of-concept studies using biobanked human specimens. However, this technology has seldom been applied to human atherosclerotic lesions. This study is a trial to benchmark the application of the multiplex imaging platform PhenoCycler to biobanked human coronary lesions. We hypothesize that this technology is a powerful tool to prove theories raised by previous studies: SMCs initiate foam cell formation and inflammation is associated with phenotypic switching in SMCs. Methods: We created an 8-plex imaging panel to map lesion cells previously identified as key players in atherogenesis, including foam cells from SMC and macrophage origins, CD68 + SMCs, apoptotic cells, and cells expressing inflammatory cytokines interleukin-1β and tumor necrosis factor α. They were imaged simultaneously on each section of early human lesions (n=9) to test theories related to foam cell formation, phenotypic transition, and inflammatory cytokines. Results: Foam cells of SMC origin greatly outnumbered those of macrophage origin and were enriched in the deep intima, where lipids accumulate in early atherogenesis, distinct from macrophage foam cells in the superficial intima. A higher presence of CD68 + SMCs was observed among lesion SMCs highly expressing interleukin-1β, but not TNF-α. Highly inflamed SMCs exhibited a trend of increased apoptosis compared to macrophages with similar cytokine levels. Conclusions: Our multiplex imaging results confirmed that SMCs form the majority of foam cells in early atherogenesis, and their phenotypic transition to macrophage-like is related to inflammation. Applying multiplex imaging to biobanked human lesions unlocks opportunities to prove that theories based on animal models and cultured cells apply to human atherogenesis.