Many types of cells live in a mechanical environment and are sensitive to changes in mechanical forces. A few examples of these mechanical load-responsive cells include fibroblasts in skin, osteocytes in bones, chondrocytes in cartilage, and endothelial cells lining the blood vessels. These cells in vivo are subjected to tension, compression, shear stresses, hydrostatic pressure, or a combination of these forces (Figure 16.1). Mechanical forces on cells regulate a wide range of cellular events, including proliferation, differentiation, gene expression, and protein secretion. 13,23,35,52,67,72,128,132,135,161,175 As such, mechanical forces on cells have a profound effect on tissue homeostasis and pathophysiology. Therefore, in vitro model systems have been developed over the years to investigate cellular mechanobiological responses under well-controlled mechanical loading conditions. 21,68 A schematic illustration of the mechanical forces acting on cells. https://s3-euw1-ap-pe-df-pch-content-public-u.s3.eu-west-1.amazonaws.com/9780429444982/6a44cb2a-ac79-4ad2-aa01-8574565384bf/content/fig16_1.jpg"/>