In the pathogenesis of atherosclerosis, monocytes migrate into the intima and transform into which type of cells?

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

Answer: (D)

Monocytes that enter the arterial intima differentiate into macrophages. In the vessel wall, these macrophages ingest modified lipids (notably oxidized LDL) through scavenger receptors and become lipid-laden foam cells, laying down the fatty streaks that start atherosclerotic lesions. Beyond forming foam cells, macrophages release inflammatory mediators and matrix-degrading enzymes that drive plaque progression and potential instability. Lymphocytes are involved in plaque inflammation but do not arise from monocytes transforming into them; smooth muscle cells come from the media and migrate into the intima, while neutrophils are transient inflammatory cells, not the result of monocyte differentiation in this context.