P136 ALTERED ADVENTITIAL COLLAGEN FIBRIL MECHANICS AND MORPHOLOGY WITH HIGH PULSE WAVE VELOCITY

• Main Authors: Zhuo Chang, Maria Lyck Hansen, Lars Melholt Rasmussen, Riaz Akhtar
• Format: Article
• Language: English
• Published: Atlantis Press 2017-12-01
• Series: Artery Research
• Online Access: https://www.atlantis-press.com/article/125930309/view

Background: Arterial stiffening, occurring as part of the natural aging process of the artery, is well- established as a powerful predictor of cardiovascular disease. However, little is known about how localised changes in the extracellular matrix and mechanical properties of arterial tissue contribute to gross stiffening in the vasculature, particularly in the adventitia. The mechanical properties of the adventitia are attributed to the collagen fibrils which exhibit high tensile strength when an axial load is placed on the vessel. Objective: To determine the relationship between the adventitial collagen fibril properties and carotid-femoral pulse wave velocity (PWV). Methods: 16 patients were split into high PWV (13.6±1.1ms−1) and low (8.5±0.3ms−1) PWV groups (t-test, P < 0.001). Internal mammary arteries (IMAs) which were collected during coronary artery bypass grafting (CABG) were used to nano-scale characterisation of the tissue with atomic force microscopy (AFM). AFM was used to determine nanomechanical properties and collagen fibril morphology. Results: Abundant, highly oriented collagen fibrils were observed in the adventitial layer in both groups. The adventitia had high elastic modulus values in the high PWV group (Low PWV = 2298.64±75.38MPa; High PWV = 2734.63±95.52MPa, P < 0.001). The collagen fibril diameters were found to be higher in patients with high PWV (Low PWV = 117.23±22.19nm, High PWV = 119.18±21.96nm, P < 0.001). Conclusion: Nanomechanical properties and collagen fibril morphology in arterial tissue associated with carotid-femoral PWV. Nano-scale changes in the IMA are therefore indicative of systematic changes in arterial stiffness in the vasculature.