In Vivo Non-Invasive Analysis of the Mechanical Properties of Vessel Walls using Vibrational Optical Coherence Tomography

In this study we use vibrational optical coherence tomography and ultrasound to image and measure the mechanical properties of arteries and veins in vivo at rest and after running. Our results suggest that several arteries and veins are tethered together via the surrounding ECM, both laterally and longitudinally. The collagen fibers and smooth muscle cells of arterial and venous walls give rise to a mechano-vibrational peak at 140-160 Hz with a modulus of between 4 and 5 MPa. Exercise increases the arterial modulus by about 2 MPa and can influence the properties of surrounding arteries and veins via the adjacent extracellular matrix. It is concluded that lateral vascular tethering results in effective stress transfer between arteries and neighboring veins. This limits stress concentrations and transmits mechanical information between the arterial and venous sides of the vascular system. Longitudinal tethering provides mechanical coupling up and down the arterial system that conveys loading information via the wall shear stress wave that propagates through the vascular tree. In this manner local changes in external and internal mechanical loading can influence anabolic and catabolic responses in other segments of the vasculature as a result of mechanotransduction.

Keywords:ECM= Extracellular Matrix; VOCT= Vibrational Optical Coherence Tomography