Control of the shape of a thrombus-neointima-like structure by blood shear stress

Fluid mechanical factors are thought to influence vascular morphogenesis. Here we show how, blood shear stress regulates the shape of a thrombus-neointima-like tissue on a polymer micro-cylinder implanted in the center of the rat vena cava with the micro cylinder perpendicular to blood flow. In this model, the micro-cylinder is exposed to a laminar flow, with a known shear stress field in the leading region and a vortex flow in the trailing region. At 1, 5, 10, 20, and 30 days after implantation, it was found that the micro-cylinder was encapsulated by, a throinbus-neointima-like tissue with a streamlined body, profile. The highest growth rate of the thrombus-neointima-like tissue it-as found along the trailing and leading stagnation edges of the micro-cylinder Blood Shear stress in the laminar flow, region was inversely correlated with the rate of thrombus formation and cell proliferation, and the percentage of smooth muscle a actin-positive cells. These biological changes were also found in the trailing vortex flow region, which it-as associated with lowered shear stress. These results suggest that blood shear stress regulates the rate of thrombus and neointimal formation and, thus, influences the shape of the thrombus-neointima-like structure in the present model.