Characteristics of vascular wall cells subjected to dynamic cyclic strain and fluid shear conditions in vitro

We recently developed an in vitro silicone rubber tubular apparatus, the vascular simulating device (VSD), which simulates pressure, flow, and strain characteristics of peripheral arteries (Benbrahim et al., 1994, J. Vasc. Surg. 20, 184-194). In this report, we tested the ability of silicone rubber surfaces to support the growth and differentiation of endothelial cells (EC) and smooth muscle cells (SMC) and studied the effects of arterial levels of pressure, flow, and strain on these properties. Human umbilical and saphenous vein EC and bovine aortic EC and SMC were cultured on coated and uncoated silicone rubber in flat and tubular configurations (6 mm inner diameter) and on tissue culture plastic (TCP). Attachment, growth, and differentiation were compared on these surfaces. In addition, the effects of arterial pressure, flow, and strain conditions on adhesion and subsequent growth and differentiation were studied in the tubular configuration. Attachment and growth of vascular wall cells on fibronectin-coated silicone rubber was similar to that obtained on TCP. Application of arterial levels of pressure, flow, and strain did not alter adhesion of the cells to the tubes. Subsequent passage of these cells demonstrated that attachment, growth, and differentiation (uptake of LDL and expression of factor VIII-related antigen by EC and expression of muscle-specific actin by SMC) were similar in cells derived from experimental and control tubes which were not subjected to arterial conditions. Finally, mRNA expression of specific "housekeeping" genes was similar in cells isolated from experimental and control tubes. We conclude that the VSD supports the culture of viable and differentiated EC and SMC. These experiments demonstrate that it is possible to evaluate the effects of arterial strain and fluid shear on vascular wall cells in vitro, in a configuration similar to the blood vessel wall.