Bilayered constructs aimed at osteochondral strategies: the influence of medium supplements in the osteogenic and chondrogenic differentiation of amniotic fluid-derived stem cells.
ABSTRACT The development of osteochondral tissue engineered interfaces would be a novel treatment for traumatic injuries and aging associated diseases that affect joints. This study reports the development of a bilayered scaffold, which consists of both bone and cartilage regions. On the other hand, amniotic fluid-derived stem cells (AFSCs) could be differentiated into either osteogenic or chondrogenic cells, respectively. In this study we have developed a bilayered scaffolding system, which includes a starch/polycaprolactone (SPCL) scaffold for osteogenesis and an agarose hydrogel for chondrogenesis. AFSC-seeded scaffolds were cultured for 1 or 2 weeks in an osteochondral-defined culture medium containing both osteogenic and chondrogenic differentiation factors. Additionally, the effect of the presence or absence of insulin-like growth factor-1 (IGF-1) in the culture medium was assessed. Cell viability and phenotypic expression were assessed within the constructs in order to determine the influence of the osteochondral differentiation medium. The results indicated that, after osteogenic differentiation, AFSCs that had been seeded onto SPCL scaffolds did not require osteochondral medium to maintain their phenotype, and they produced a protein-rich, mineralized extracellular matrix (ECM) for up to 2 weeks. However, AFSCs differentiated into chondrocyte-like cells appeared to require osteochondral medium, but not IGF-1, to synthesize ECM proteins and maintain the chondrogenic phenotype. Thus, although IGF-1 was not essential for creating osteochondral constructs with AFSCs in this study, the osteochondral supplements used appear to be important to generate cartilage in long-term tissue engineering approaches for osteochondral interfaces. In addition, constructs generated from agarose-SPCL bilayered scaffolds containing pre-differentiated AFSCs may be useful for potential applications in regeneration strategies for damaged or diseased joints.
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ABSTRACT: Bilayered porous scaffolds have recently attracted interest because of their considerable promise for repairing osteochondral defects. However, determination of optimal pore size in bilayered porous scaffolds remains an important issue. This study investigated the in vivo effects of pore size in bilayered scaffolds using a rabbit model of osteochondral defects. We fabricated five types of integrated bilayered poly(lactide-co-glycolide) (PLGA) scaffolds with different pore sizes in the chondral and osseous layers (50-100 µm, 100-200 µm, 200-300 µm, and 300-450 µm). A subset of bilayered scaffolds seeded with or without allogenic bone marrow mesenchymal stem cells (BMSCs) was implanted in rabbit osteochondral defects. All of the cell/scaffold composite constructs supported the simultaneous regeneration of articular cartilage and subchondral bone, but the best results were observed in cell-seeded PLGA scaffolds with 100-200 µm pores in the chondral layer and 300-450 µm pores in the osseous layer. Our study supports the concept that the effects of pore size on osteochondral repair should be taken into consideration during scaffold design for tissue engineering. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A:, 2013.Journal of Biomedical Materials Research Part A 05/2013; · 2.83 Impact Factor
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ABSTRACT: The emerging field of tissue engineering reveals promising approaches for the repair and regeneration of skeletal tissues including the articular cartilage, bone, and the entire joint. Amongst the myriad of biomaterials available to support this strategy, hydrogels are highly tissue mimicking substitutes and thus of great potential for the regeneration of functional tissues. This review comprises an overview of the novel and most promising hydrogels for articular cartilage, osteochondral and bone defect repair. Chondro- and osteo-conductive and -instructive hydrogels are presented, highlighting successful combinations with inductive signals and cell sources. Moreover, advantages, drawbacks, and future perspectives of the role of hydrogels in skeletal regeneration are addressed, pointing out the current state of this rising approach.International Orthopaedics 06/2014; · 2.32 Impact Factor
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ABSTRACT: Chondrogenically primed bone marrow derived mesenchymal stem cells (MSCs) have been shown to become hypertrophic and undergo endochondral ossification when implanted in vivo. Modulating this endochondral phenotype may be an attractive approach to engineering the osseous phase of an osteochondral implant. The objective of this study was to engineer an osteochondral tissue by promoting endochondral ossification in one layer of a bi-layered construct and stable cartilage in the other. The top-half of bi-layered agarose hydrogels were seeded with culture expanded chondrocytes (termed chondral layer) and the bottom half of the bi-layered agarose hydrogels with MSCs (termed osseous layer). Constructs were cultured in a chondrogenic medium for 21 days and thereafter were either maintained in a chondrogenic medium, transferred to a hypertrophic medium, or implanted subcutaneously into nude mice. This structured chondrogenic bi-layered co-culture was found to enhance chondrogenesis in the chondral layer, appearing to help re-establish the chondrogenic phenotype that is lost in chondrocytes during monolayer expansion. Furthermore, the bi-layered co-culture appeared to suppress hypertrophy and mineralisation in the osseous layer. The addition of hypertrophic factors to the media was found to induce mineralisation of the osseous layer in vitro. A similar result was observed in vivo where endochondral ossification was restricted to the osseous layer of the construct leading to the development of an osteochondral tissue. This novel approach represents a potential new treatment strategy for the repair of osteochondral defects.Acta biomaterialia 11/2012; · 5.68 Impact Factor