What is the predominant cellular element of the vascular media that plays an important role in normal vascular repair and pathologic processes?

What is the predominant cellular element of the vascular media that plays an important role in normal vascular repair and pathologic processes?

• A. Smooth muscle
• B. Endothelial cells
• C. Fibroblasts
• D. Pericytes

Answer: (A)

Smooth muscle cells are the predominant cellular element of the vascular media. They form the concentric layers that surround the lumen and control vessel diameter through contraction and relaxation, regulating blood flow and pressure. But they aren’t just contractile; smooth muscle cells can switch from a contractile to a synthetic phenotype, proliferate, migrate, and synthesize extracellular matrix as part of normal repair after vascular injury. This same plasticity underlies pathologic remodeling, such as neointimal hyperplasia and remodeling seen in atherosclerosis or after angioplasty. Endothelial cells line the intima, not the media; pericytes are mainly in microvessels and support capillary stability, while fibroblasts are more associated with the adventitia. Thus, smooth muscle cells best explain both the normal repair process and the pathologic changes of the vascular media.

Smooth muscle cells are the predominant cellular element of the vascular media. They form the concentric layers that surround the lumen and control vessel diameter through contraction and relaxation, regulating blood flow and pressure. But they aren’t just contractile; smooth muscle cells can switch from a contractile to a synthetic phenotype, proliferate, migrate, and synthesize extracellular matrix as part of normal repair after vascular injury. This same plasticity underlies pathologic remodeling, such as neointimal hyperplasia and remodeling seen in atherosclerosis or after angioplasty. Endothelial cells line the intima, not the media; pericytes are mainly in microvessels and support capillary stability, while fibroblasts are more associated with the adventitia. Thus, smooth muscle cells best explain both the normal repair process and the pathologic changes of the vascular media.