A Mechanical Model of Porcine Vascular Tissues-Part I: Determination of Macromolecular Component Arrangement and Volume Fractions

Blood vessels are designed to transport blood to and from the various tissues of the body. To accomplish this task, they must support enough stress to prevent mechanical failure under normal physiological conditions yet must be able to remain flexible and elastic enough to aid the heart in maintaining blood flow. The endothelium, smooth muscles, fibroblasts and the extracellular matrix must act in concert to produce and maintain a material that is capable of withstanding these stresses and alter the mechanics of vascular tissue if needed. Over time, these requirements have led to the widely accepted view that the form and function of biological materials are intimately connected. The purpose of this study was to determine the morphological differences between various blood vessels and the impact of these differences, if any, on the mechanics of these tissues. The results of our work suggest that all vascular smooth muscle cells are embedded in a collagen matrix with a 1:1 volume fraction ratio. The primary differences between blood vessels of the juvenile porcine model appear to involve differences in the volume fraction and density of elastic tissue and medial thickness. In addition, cross-linking probably plays a significant role in altering mechanical properties.