Recent progress of vascular graft engineering in Japan.

The development of a small-diameter vascular graft has long been awaited. This review covers research activities, achievements and progress on vascular engineering in Japan, which was conducted over the last decade. The article includes recently developed experimental scaffolds, biologically active artificial extracellular matrices (ECMs) or non-fouling synthetic coatings, cell sourcing including the autologous vascular cell type, endothelial progenitor cells and genetically-engineered, temporary endothelial-like cells. The discussions were presented from biomechanical, biomaterial, cellular and tissue aspects. Once the mechano-biological and biologically active extracellular milieus are established in a designed vascular graft, the functional, structural and mechanical tissue morphogenesis and adaptation of implanted vascular grafts may proceed with implantation duration, and the spatio-temporal tissue modulations at cytokine, cellular, ECM levels under physiological stress proceed to regenerate vascular tissue architecture. The ultimate solution to a small-diameter vascular graft should be realized by optimal combinations of these factors.