Abstract
Incorporation of the hierarchical structure made of orientated cells into a hybrid vascular prosthesis might enable us to build a more vital and functional graft. Along with this hypothesis, we attempted to organize the smooth muscle cell layer with regulated orientation in vitro. A “hybrid artificial media” was prepared with inoculation of arterial smooth muscle cells (SMCs) derived from bovine aorta into Type I collagen gel in which a silicone tube was embedded. Subsequently, the “hybrid artificial media” was subjected to the mechanical stimulation, resembling a pulsatile stress in vivo, which was induced by periodic ballooning of the silicone tube with an amplitude of 5% in diameter and a frequency of 60 times per minute. In stress-loaded gels, bipolar spindle-shaped SMCs and collagen fiber bundles exhibited coaxial orientation around the tubes which proceeded time-dependently, while, in non-stressed gels, polygonal-shaped SMCs and collagen fiber networks showed random orientation. The mechanical stress-loaded “hybrid artificial media” constructed a highly-ordered structure similar to the media of native muscular arteries.
