INFLUENCE OF PULSATILE FLOW ON THE BEHAVIOR OF HUMAN FIBROBLASTS ADHERED TO GLASS

In the human body, cells contacting biomaterials surfaces are frequent ly exposed to pulsatile shear stresses, e.g. blood vessel prostheses. Most studies involving shear, however, try to achieve a steady, pulse- free shear stress in studying cell-biomaterial interactions. In this s tudy, human fibroblasts adhering to glass were exposed to an applied 0 .5 Hz square-wave pulsatile shear, created in a parallel plate flow ch amber by a computer-driven pump. Cells were also exposed to the single lower and higher shear stresses making up the square wave in the pres ence or absence of pressure variations due to the peristaltic roller p ump. Results indicate that cells exposed to the applied square-wave re gime showed a detachment rate in between that of the single shear stre sses making up the square wave. Furthermore, the presence of the pulsa tions gave rise to elongated cell shapes in the direction of flow and the formation of a more extensive filopodial network than in the absen ce of pulsations. This was also true for cells exposed to the high she ar component in the presence of pressure variations. Cells exposed to the high shear component without any pressure variations, however, ada pted spherical shapes after the onset of flow.