Mold-shaped, nanofiber scaffold-based cartilage engineering using human mesenchymal stem cells and bioreactor

Background. Mesenchymal stem cell (MSC)-based tissue engineering is a promising future alternative to autologous cartilage grafting. This study evaluates the potential of using MSCs, seeded into electrospun, biodegradable polymeric nanofibrous scaffolds, to engineer cartilage with defined dimensions and shape, similar to grafts used for subcutaneous implantation in plastic and reconstructive surgery. Materials and methods. Human bone marrow derived MSCs seeded onto nanofibrous scaffolds and placed in custom-designed molds were cultured for up to 42 days in bioreactors. Chondrogenesis was induced with either transforming growth factor-beta 1 (TGF-beta I) alone or in combination with insulin-like growth factor-I (IGF-I). Results. Constructs exhibited hyaline cartilage histology with desired thickness and shape as well as favorable tissue integrity and shape retention, suggesting the presence of elastic tissue. Time-dependent increase in cartilage matrix gene expression was seen in both types of culture: at Day 42, TGF-beta 1/IGF-I treated cultures showed higher collagen Type 2 and aggrecan expression. Both culture conditions showed significant time-dependent increase in sulfated glycosaminoglycan and hydroxyproline contents. TGF-beta 1/IGF-I-treated samples were significantly stiffer; with equilibrium compressive Young's modulus values reaching 17 kPa by Day 42. Conclusions. The successful ex vivo development of geometrically defined cartilaginous construct using customized molding suggests the potential of cell-based cartilage tissue for reconstructive surgery. (c) 2008 Elsevier Inc. All rights reserved.