In cartilaginous tissues, perichondrium cambium layer may be the source of new cartilage. Human nasal septal perichondrium is considered to be a homogeneous structure in which some authors do not recognize the perichondrium internal zone or the cambium layer as a layer distinct from adjacent cartilage surface. In the present study, we isolated a chondrogenic cell population from human nasal septal cartilage surface zone. Nasoseptal chondrogenic cells were positive for surface markers described for mesenchymal stem cells, with exception of CD146, a perivascular cell marker, which is consistent with their avascular niche in cartilage. Although only Sox-9 was constitutively expressed, they also revealed osteogenic and chondrogenic, but not adipogenic, potentials in vitro, suggesting a more restricted lineage potential compared to mesenchymal stem cells. Interestingly, even in absence of chondrogenic growth factors in the pellet culture system, nasoseptal chondrogenic cells had a capacity to synthesize sulfated glycosaminoglycans, large amounts of collagen type II and to a lesser extent collagen type I. The spontaneous chondrogenic potential of this population of cells indicates that they may be a possible source for cartilage tissue engineering. Besides, the pellet culture system using nasoseptal chondrogenic cells may also be a model for studies of chondrogenesis.

Silks are naturally occurring polymers and fibroin, its filament core protein, has been shown to support stem cell differentiation in vitro, and promote tissue repair in vivo. The aim of this study is to develop a biomaterial based on silk-fibroin fibers that can be associated with mesenchymal progenitor cells from human perichondrium in vitro, in order to promote auricular reconstruction in vivo. Silk-fibroin concentrate was dissolved with formic acid solution and freeze-dried in auricular moulds. Fibroin-based material was characterized by scanning electron microscopy and by cytotoxic assays. Perichondrium mesenchymal progenitor cells were characterized by flow cytometry. They expressed the standard mesenchymal stem cell markers, and were able to differentiate into several mesenchymal lineages in vitro. This fibroin-based material is a three-dimensional fibrillar scaffold, non-woven and biocompatible, which was also well integrated with alginate and mesenchymal cells.