Structural remodelling of the vascular wall in relation to ageing and arterial stiffening

Abstract

Structural remodelling of the vascular wall has been investigated in this study in terms of ageing and the process of vascular stiffening. While common structural adaptations are often presumed for ageing and vascular stiffening, recent evidence suggests that independent alterations may occur. Age-associated vascular remodelling was investigated in both the central elastic artery- the aorta and the smaller muscular artery- the internal mammary artery (IMA) by the quantification of matrix metalloproteinase-2 and -9 activities in the arterial homogenates, using gelatin zymography. MMP-2 and -9 activities were localised within the vessel wall using in situ zymography. These studies demonstrated an age-associated increase in aortic MMP-2 activity and activation, confirming the results of previous animal studies. Age-related changes in matrix degrading activity were not present in the IMA. Structural remodelling of the vessel wall in relation to both ageing and arterial stiffening was investigated using human vascular tissue samples from subjects following the measurement of arterial stiffriess. Aortic stiffriess was measured by pulse wave velocity (PWV), and augmentation index (AIx) was obtained to provide indices of systemic arterial stiffriess. MMP-2 and -9 activities were quantified in the arterial homogenates to assess the activity of these enzymes in relation to measures of vascular stiffhess. Collagen content was also measured in vascular tissue following Sirius red staining, as was intimal thickness and elastin tissue fragmentation following elastin staining. The results demonstrated increased aortic MMP-9 expression in subjects with stiffer arteries and increased