Foam cells are derived from which cell type?

Foam cells are derived from which cell type?

• A. Endothelial cells
• B. Lymphocytes
• C. Smooth muscle cells
• D. Macrophages

Answer: (D)

Foam cells come from macrophages. In the vessel wall, circulating monocytes migrate into the intima and differentiate into macrophages. These macrophages ingest large amounts of lipids, especially modified LDL such as oxidized LDL, via scavenger receptors. Unlike normal LDL uptake, this process isn’t downregulated by cholesterol buildup, so the macrophages continue taking in lipids. The cholesterol is stored as cholesterol esters in cytoplasmic lipid droplets, giving the cell a characteristic foamy appearance. This lipid-laden state forms the fatty streaks that are early signs of atherosclerotic plaque. Endothelial cells and lymphocytes don’t become foam cells, and while smooth muscle cells can become lipid-laden under some conditions, the classic origin of foam cells in pathology questions is macrophages.

Foam cells come from macrophages. In the vessel wall, circulating monocytes migrate into the intima and differentiate into macrophages. These macrophages ingest large amounts of lipids, especially modified LDL such as oxidized LDL, via scavenger receptors. Unlike normal LDL uptake, this process isn’t downregulated by cholesterol buildup, so the macrophages continue taking in lipids. The cholesterol is stored as cholesterol esters in cytoplasmic lipid droplets, giving the cell a characteristic foamy appearance. This lipid-laden state forms the fatty streaks that are early signs of atherosclerotic plaque. Endothelial cells and lymphocytes don’t become foam cells, and while smooth muscle cells can become lipid-laden under some conditions, the classic origin of foam cells in pathology questions is macrophages.