Vascular tissue engineering : designer arteries.

The fields of vascular biology and vascular medicine are so intertwined that advances in one predict, explain, or are required for progress in the other. Bypass grafting, which once served as a “bailout” procedure,1 2 is now performed more than 600 000 times annually in the United States. In major part, this increase can be attributed to a surge in understanding of the vascular response to injury. At the same time, the science of vascular biology has been primarily stimulated by the clinical imperative to combat complications that ensue from vascular interventions.3 Thus, when a novel vascular biological finding or cardiovascular medical/surgical technique is presented, we are required to ask the 2-fold question: what have we learned about the biology of the blood vessel, and how might this knowledge be used to enhance clinical perspective and treatment? The innovative method of engineering arterial conduits presented by Campbell et al4 in this issue of Circulation Research presents us with just such a challenge, and I will attempt to deal with the biological and clinical ramifications of this work. Although routinely applied and ubiquitously used, vascular grafting is not without significant constraints and complications.3 Arterial conduits are in limited supply and restricted dimensions. Venous conduits are more abundant but lack vasomotor tone and are prone to thrombotic and hyperplastic occlusion and, less frequently, infection. Veins and arteries must be harvested from sites that leave wounds that can break down or become infected. Synthetic materials do not fare well in small-bore vascular beds and are excessively thrombotic. Graft passivation has been attempted to minimize material-blood interaction by surface modification with coatings of proteins,5 polymer materials, or cells.6 7 Although somewhat successful in limiting thrombosis and hyperplasia, such linings do not provide vascular responsiveness or other biochemical secretory …