Cyclic Strain Stimulates Endothelial Cell Proliferation: Characterization of Strain Requirements

Previous studies from our laboratory show that vascular cell biology can be modulated by cyclic strain. However, the precise relationship between cyclic strain and endothelial cell responsiveness remains unclear. The objective of this study was to better characterize this relationship by examining the proliferative response of endothelial cells to sharply defined ranges of strain. This was accomplished by seeding bovine aortic endothelial cells (passages 1–3; N = 9) (10,000 cells/cm2) either on the outer 2/3 (periphery) or the inner 1/3 (center) regions of collagen-coated flexible bottomed wells. The wells were deformed at a frequency of 100 cycles per minute with either -5 kPa vacuum (center, 0–3.2% strain; periphery, 3.2–11% strain) or -20 kPa vacuum (center, 0.37–6.3% strain; periphery, 6.3–25% strain) for up to 5 days. Static, unstretched wells served as controls. At 5 days, endothelial cells subjected to either low (-5 kPa) or high vacuum (-20 kPa), exhibited a stimulated proliferative response in bo...