Localised micro-mechanical stiffening in the ageing aorta

Publication date: October 2011 Source:Mechanisms of Ageing and Development, Volume 132, Issue 10 Author(s): Helen K. Graham , Riaz Akhtar , Constantinos Kridiotis , Brian Derby , Tribikram Kundu , Andrew W. Trafford , Michael J. Sherratt Age-related loss of tissue elasticity is a common cause of human morbidity and arteriosclerosis (vascular stiffening) is associated with the development of both fatal strokes and heart failure. However, in the absence of appropriate micro-mechanical testing methodologies, multiple structural remodelling events have been proposed as the cause of arteriosclerosis. Therefore, using a model of ageing in female sheep aorta (young: <18 months, old: >8 years) we: (i) quantified age-related macro-mechanical stiffness, (ii) localised in situ micro-metre scale changes in acoustic wave speed (a measure of tissue stiffness) and (iii) characterised collagen and elastic fibre remodelling. With age, there was an increase in both macro-mechanical stiffness and mean microscopic wave speed (and hence stiffness; young wave speed: 1701±1ms−1, old wave speed: 1710±1ms−1, p <0.001) which was localized to collagen fibril-rich regions located between large elastic lamellae. These micro-mechanical changes were associated with increases in both collagen and elastic fibre content (collagen tissue area, young: 31±2%, old: 40±4%, p <0.05; elastic fibre tissue area, young: 55±3%, old: 69±4%, p <0.001). Localised coll...
Source: Mechanisms of Ageing and Development - Category: Geriatrics Source Type: research