The effect of calcium on the mechanical behaviour of aorta media elastin and collagen.

Mechanical tests were conducted on rings of pig thoracic aorta that had been treated with calcium ions to evaluate their effect on aorta media collagen and elastin. There was an increase in stiffness just before rupture and a decrease in storage energy when calcium was introduced into intact rings, but there was no significant difference in mechanical properties when it was introduced into the elastin framework of the media. The calcium was able to bind to the intact aorta media far more readily than to the elastin alone, suggesting that the collagen and muscle framework were far more susceptible to the introduction of calcium than elastin. The calcium content rose along the length of the aorta, as did the collagen content, whilst the elastin content fell, which was also reflected in the change in mechanical properties along the aorta.