Tissue engineering of the vascular system: from capillaries to larger blood vessels

Tissue engineering is a novel approach to the repair of wounded tissues. Ap plication of this technology to the vascular system is important because of the fundamental nutritional role of the vasculature. This perspective is c urrently being applied to the first tissue-engineered organ: the skin. Know ledge of capillary constitution and factors inducing their formation has le d to attempts to induce their formation in reconstructed skin. Such Vascula r conduits grown in vitro could also benefit the nutrition of tissues and o rgans in vivo. The paper reviews recent progress in the in-vitro developmen t of vascularised skin and tissue-engineered blood vessels. It points out t he necessity of obtaining pure and well-characterised cultures of the diffe rent cell populations that are the basic building blocks of the reconstruct ions. The importance of an adequate cell-culture environment (nutrients and bi- or tri-dimensional scaffolds for cells) for success in elaborating a r econstructed living tissue able to replace the original is emphasised. Engi neered tissues can serve not only as tissue replacements bur also as in-vit ro models for research in organ physiology and physiopathology. These tissu es are also attractive vehicles for gene therapy, one of the more promising new methods of disease treatment.