Summary
Arterial ageing may be associated with a reduction in vasodilation due to increased
reactive oxygen species (ROS) production, whereas endothelial cell activation induces
procoagulant changes. However, little is known on the effect of ageing on expression
of anticoagulant endothelial markers such as endothelial protein C receptor (EPCR).
To study age-associated alterations in smooth muscle cell (SMC) and endothelial cell
(EC) structure and function, the aorta was isolated from 10-week-and 12– and 24-month-old
C57BL/6J mice and analysed for its expression of genes involved in senescence, oxidative
stress production, coagulation and matrix remodelling. In addition, vasorelaxation
experiments were performed using 10-week-and 24-month-old thoracic aortic ring segments
in organ chamber baths. The media thickness of the thoracic aorta progressively increased
with age, associated with hypertrophy of vascular SMCs. Basal nitric oxide production
and sensitivity to acetylcholine-mediated vasodilation in thoracic aorta rings was
reduced with age, whereas no significant differences in ROS production could be demonstrated.
Gene expression of tissue factor, EPCR and von Willebrand factor was not affected
by ageing of the aorta, whereas that of thrombomodulin was mildly reduced and that
of xanthine dehydrogenase, NADPH oxidase 4, tumour necrosis factor-α and vascular
cell adhesion molecule-1 significantly enhanced. In conclusion, a reduction in endothelial
cell-mediated vasodilation in aged thoracic aortas of C57BL/6J mice was accompanied
by a shift towards a pro-inflammatory state of the endothelium.
Keywords
Vascular ageing - C57BL/6J mice - endothelial dysfunction - EPCR