Foam Cells: The Origin of Formation and Target for Plant-derived Bioactive Compounds

Foam cells play a crucial role in the initiation and progression of atherosclerosis, a condition marked by the development and growth of plaques that narrow blood vessel lumens. This narrowing can prevent normal blood flow and, in severe cases, lead to plaque rupture and blood clot formation, which can cause stroke or myocardial infarction. The origin of foam cells is diverse, arising from monocytes, vascular smooth muscle cells, stem/progenitor cells, and dendritic and endothelial cells. In their attempt to eliminate excess lipoproteins and cholesterol, foam cells inadvertently contribute to plaque development and rupture. Cholesterol uptake, efflux, and esterification are the major processes regulating foam cell formation. Advances in technology, such as the identification of cell-surface markers for lineage tracing and single-cell RNA sequencing, have unveiled diverse molecular mechanisms involved in the formation of foam cells from different origins, offering new insights into plaque formation and potential targets for anti-foam cell therapies. In this review, we focus on recent studies exploringthe inhibitory effects of medicinal plants and their bioactive components on foam cell formation. Various mechanisms are explored, including the inhibition of cholesterol uptake and the up-regulation of cholesterol efflux, as well as the suppression of inflammatory and adhesion activities. Emphasising a cellular target-based therapeutic approach, this review envisions the development of innovative plant-based medications for atherosclerosis treatment.