Bilayered scaffolds colonized with dental pulp stem cells for osteochondral tissue engineering application

Abstract

The development of osteochondral tissue engineered interfaces would be a novel treatment for traumatic injuries and aging associated diseases that affect joints [1]. Dental Pulp Stem Cells (DPSC) are a promising alternative source in cell-based tissue engineering for the easily recruitment, the self-renewal and differentiation potential, being able to differentiate toward chondrogenic and osteogenic lineage [2]. The aim of this study was to develop scaffold that would support an osteochon- dral interface. DPSCs, isolated from dental pulp by selection with c-Kit-CD34 and STRO1 antibodies, were either cultured on fibroin and collagen scaffolds and differ- entiated into osteogenic cells or encapsulated in alginate and differentiated into chondrogenic cells. After 3 weeks of culture, the differentiation of the cell-scaffold con- structs was analyzed by histology and immunofluorescence. The cell seeded scaffolds were then brought together (fibroin+alginate and collagen+alginate) in order to form a combination that would provide a supportive scaffold for bone formation as well as a soft matrix for cartilage growth. The resulting single constructs were cultured for 2 weeks in a osteochondral media, developed by combining some of the growth factors and nutrients of osteoand chondrogenic media. The constructs were then characterized for expression of bone and cartilage specific markers to evaluate the capability of the cells to not dedifferentiate in the new cultured conditions. We demonstrated that both collagen and fibroin appear to be excellent scaffold for cells differentiated into osteogenic lineage, although they have different structural characteristics. Similarly, the alginate has allowed cells to produce ECM-rich in collagen II and aggrecan during chondrogenic differentiation. Moreover DPSC in the bilay- ered constructs remain viable and differentiated even in the osteochondral medium. Thus the integrated fibroin-alginate or collagen-alginate proved to be functional in vitro and may lead to the development of new strategies for osteochondral repair and regeneration.