Tissue engineering and skeletal diseases.

Tissue engineering, a cross between the science of the living organism and that of engineering, aims to replace, maintain or improve human tissue functions, by means of tissue substitutes containing living elements. Thus, it is about production of artificial tissue, using (alone or in combination) cells, matrix or bioactive factors. Their association gives rise to a hybrid biomaterial combining biological components (cells, growth factors or adhesion proteins) and materials (polymers, ceramics). The applications are wide-ranging, from the skin, to the liver, or to the cornea as well as to the locomotor system. Bone tissue engineering has advanced the most in this field, partly because of the progress made by research into bone substitutes, although cartilage and tendons are also concerned. This technology requires cell culture (committed cells or more often bone marrow stem cells), biomaterials (porous materials with controlled architecture and cements), growth factors (such as 'Bone Morphogenetic Proteins'), the proteins implicated in cell adhesion (such as fibronectin or the aminoacid sequences specifically recognised by integrin subunits) or gene therapy (notably using transfected stem cells). Tissue engineering and regenerative stimulation of tissue are now booming on experimental and industrial levels and clinical applications are increasingly numerous. Considering the potential of these technologies, they should continue to develop widely.