Effect of pulse rate on collagen deposition in the tissue-engineered blood vessel.
The effect of mechanical stimulation on the development of tissue-engineered blood vessels was examined. In particular, three different rates of radial distension were chosen to produce a nonpulsed environment (0 beats per minute [bpm]), an adult heart rate (90 bpm), and a fetal heart rate (165 bpm). Engineered vessels were cultured for an average of 7 weeks. Vessel walls were then analyzed for collagen content and distribution. In addition, extracellular matrix remodeling was assessed through measurement of active matrix metalloproteinase type 1 (MMP-1) and tissue inhibitor of metalloproteinases type 1 (TIMP-1) levels. Vessels grown at a distension rate of 165 bpm had significantly higher collagen levels than those grown under static conditions. MMP-1 and TIMP-1 levels were also higher under pulsed conditions as compared with nonpulsed conditions. For the 90- and 165-bpm conditions, collagen and MMP-1 levels were not significantly different. TIMP-1 levels were significantly elevated at 165 bpm, indicating an increased cellular response to mechanical stimulation. Mechanical forces and their transduction represent a means to enhance the physical properties of artificial blood vessels, possibly by affecting the rate of extracellular matrix deposition and remodeling.
D000818:Animals; D001808:Blood Vessels / Q000378:metabolism; D003094:Collagen / Q000378:metabolism*; D006339:Heart Rate / Q000502:physiology*; D020781:Matrix Metalloproteinase 1 / Q000378:metabolism; D013552:Swine; D023822:Tissue Engineering; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000378:metabolism
D019715:Tissue Inhibitor of Metalloproteinase-1; D003094:Collagen; D020781:Matrix Metalloproteinase 1