[Cell therapy and its clinical applications. Cartilage cell therapy, present and future]

Articular cartilage has a very poor capacity for repair. In order to get a normal functional efficacy, the replaced tissue has to reproduce the structure, composition and physico-chemical properties of native cartilage tissue. The transplantation of cultured autologous chondrocytes into chondral defects is currently applicable only in the case of young sportive people with a limited lesion in an otherwise relatively normal joint. Recent experimental studies have shown that pluripotent mesenchymal cells from bone marrow could also repair experimental osteochondral defects. An advantage of this grafting procedure is that large areas of cartilage surface could be covered. Bone marrow cells are not so difficult to get, they have a high potency to divide and they can develop in vitro as chondrogenic, osteogenic or adipogenic cells. The present ways of research are: to characterize one or several growth factors capable to specifically induce the chondrogenic lineage; to determine nutrient and environmental conditions allowing the cultured chondrogenic cells to undergo a maturation process within the cell pellet; to elaborate three-dimensional synthetic, biodegradable polymeric scaffolds assessed with respect to chondrogenic cell adhesion, proliferation, maturation and cartilage matrix secretion; finally, to elaborate a mixed biomaterial composed of chondrogenic and osteogenic cells selectively distributed within polymeric scaffolds in order to get a better adherence of the implanted cells to the lesion sites.