Abstract Body: Background:
Hypercholesterolemia promotes lipid accumulation and inflammation of the aortic valve, contributing to early aortic valve disease. The cellular and spatial mechanisms governing regression of lipid-driven valve remodeling remain poorly defined, leaving it unclear whether therapies should eliminate disease-associated macrophages or reprogram their interactions within valve tissue. This exploratory study tested the hypothesis that regression involves reprogramming of macrophage–vascular niches rather than macrophage lineage replacement.
Methods:
Spatial transcriptomics integrated with histology was used to characterize aortic valve remodeling in male Reversa mice in four conditions: wild type, hypercholesterolemic, lipid normalization, and lipid normalization with the pro-resolving Ac2-26 peptide. Valve annulus, cusp base, and free cusp were analyzed relative to the full spatial dataset. Assistive computational tools were used to support data interpretation under investigator oversight.
Results:
Hypercholesterolemia promoted lipid-enriched, hypercellular remodeling of the valve annulus, cusp base, and free cusps accompanied by enrichment of macrophage, extracellular matrix, and endothelial interface programs consistent with early inflammatory aortic valve disease. Disease-associated macrophage regions expressed SPP1, TREM2, apolipoprotein E, galectin-3, and lysosomal genes. Lipid normalization did not eliminate this macrophage program, but instead was associated with macrophage-enriched regions being co-enriched with endothelial transcriptional programs (Pecam1, Cdh5, Kdr, Emcn, Vwf, Ptgis, Aqp1, Eng) and less associated with extracellular matrix–remodeling stromal niches (Col1a1, Col3a1, Fn1, Mmp12, Timp1, Postn, Thbs1), reflecting reorientation toward immune–vascular interactions and regulated tissue repair. Ac2-26 further enhanced endothelial-associated and immune–vascular interface transcriptional programs within macrophage-rich regions, without evidence of a distinct reparative macrophage lineage.
Conclusions:
Regression of lipid-driven inflammatory aortic valve remodeling occurs through spatial and functional reorientation of a persistent disease-associated macrophage program rather than lineage replacement, suggesting that resolution-directed therapies retune macrophage–vascular niches within mechanically specialized valve tissue.