Sequential enzymolysis of human aorta and resultant stress-strain behavior.

The human aorta has five major components from which the aortic walls can be characterized: mucopolysaccharides, smooth muscle, collagen, micro-fibrilar glycoprotein (associated with the elastic fiber), and elastin. Enzymes were employed to remove four of the components sequentially without destroying the mechanical characteristics of the remaining components in order to elucidate the structure-property relationship in the human aorta. Before treatment the initial mechanical behavior was recorded on an Instron Tensile testing machine. After enzymolysis the samples and controls were again tested and these results compared to their prior characteristics. Stress-strain characteristics after a sequence of enzyme treatments indicate that two of the components share the major part of the stress in the circumferential direction. These components, elastin and collagen, contribute as if they were in parallel to each other with the collagen in a crimped state.