Research on the Biomechanics of Blood Vessels

　Blood vessels are not merely tubes; they are intelligent pipes that adaptively change their diameter and wall thickness in response to internal pressure and flow. For instance, prolonged high blood pressure causes the vessel walls to thicken, and sustained increased blood flow results in vessel dilation. Interestingly, the thickening of the vessel walls occurs to maintain circumferential tensile stress, and the dilation happens to maintain wall shear stress (mechanical homeostasis). If this response fails, it can lead to aneurysms or hypertension. Additionally, atherosclerosis tends to develop in areas where stress is concentrated within the vessel walls. Thus, it can be said that atherosclerosis, hypertension, and aneurysms arise from the failure of the vessels' mechanical adaptation. Blood vessels are also suitable for studying responses to mechanical forces due to their relatively simple cylindrical shape. We investigate how the mechanical properties and structure of blood vessels change under various conditions.
　Specifically, we measure the mechanical properties of the aorta in rabbits and pigs using various devices developed in our laboratory. We also aim to measure the mechanical properties of cells and fiber bundles within the vessel wall on a microscopic scale to clarify the micron-order stress and strain distribution within the vessel walls.