Figure. Aortic mechanobiology.

(A) Cells of the thoracic aortic wall remodel an extracellular matrix (ECM). Endothelial cells (ECs) sense and respond to changes in wall shear stress resulting from blood flow; smooth muscle cells (SMCs) and fibroblasts (FBs) sense and respond to changes in intramural circumferential (σ_θ) and axial (σ_z) stresses resulting from blood pressure (P) and motion of the heart. Increases in P increase wall stress but adaptive thickening restores stress to normal values; decreases in P decrease stress but adaptive thinning restores stress.

(B) Cells sense and regulate the ECM via integrins and intracellular contractile structures (actin-myosin filaments). Sensing low versus high stress results in different cell signaling. Misperception of high stress as low stress can result in maladaptive remodeling.