Indicial functions of arterial remodeling in response to locally altered blood pressure.

We investigated the effect of locally altered blood pressure on the remodeling processes of the cells and extracellular matrices of the splenic and ileal arteries and used an indicial function approach to quantitatively analyze the relationship between the altered blood pressure and the remodeling processes. Blood pressure in these arteries was locally modulated by constricting the aorta at a location between the celiac and mesenteric bifurcations, resulting in a higher blood pressure at the splenic arteries then at the ileal arteries, After the pressure changes, the cross-sectional areas and the fractions of the cells and extracellular matrices of the splenic and ileal arteries were examined by electron microscopy at 2, 6, 10, 20, and 30 days. We found that both arteries remodeled, but the splenic arteries (higher blood pressure) remodeled more rapidly and to a larger degree than the ileal arteries (lower pressure compared with the splenic arteries) of the same animal. To verify whether an identical change in the blood pressure at the splenic and ileal arteries leads to the same remodeling process in these arteries, we created another model by constricting the aorta at a location between the mesenteric and renal bifurcations, resulting in hypertension of the same level at both splenic and ileal arteries. We found that the remodeling processes of the cells and matrices were almost identical in the arteries with similar changes in blood pressure. Thus we conclude that the remodeling processes of cells and matrices of the splenic and ileal arteries are dependent on the local blood pressure in aorta constriction-induced hypertension, and the indicial analysis is a useful approach in the description of the relationship between the blood pressure and the arterial remodeling processes.