title: Engineering cartilaginous grafts using chondrocyte-laden hydrogels supported by a superficial layer of stem cells.
abstract: During postnatal joint development, progenitor cells that reside in the superficial region of articular cartilage first drive the rapid growth of the tissue and later help direct the formation of mature hyaline cartilage. These developmental processes may provide directions for the optimal structuring of co-cultured chondrocytes (CCs) and multipotent stromal/stem cells (MSCs) required for engineering cartilaginous tissues. The objective of this study was to engineer cartilage grafts by recapitulating aspects of joint development where a population of superficial progenitor cells drives the development of the tissue. To this end, MSCs were either self-assembled on top of CC-laden agarose gels (structured co-culture) or were mixed with CCs before being embedded in an agarose hydrogel (mixed co-culture). Porcine infrapatellar fat pad-derived stem cells (FPSCs) and bone marrow-derived MSCs (BMSCs) were used as sources of progenitor cells. The DNA, sGAG and collagen content of a mixed co-culture of FPSCs and CCs was found to be lower than the combined content of two control hydrogels seeded with CCs and FPSCs only. In contrast, a mixed co-culture of BMSCs and CCs led to increased proliferation and sGAG and collagen accumulation. Of note was the finding that a structured co-culture, at the appropriate cell density, led to greater sGAG accumulation than a mixed co-culture for both MSC sources. In conclusion, assembling MSCs onto CC-laden hydrogels dramatically enhances the development of the engineered tissue, with the superficial layer of progenitor cells driving CC proliferation and cartilage ECM production, mimicking certain aspects of developing cartilage. Copyright © 2015 John Wiley & Sons, Ltd.
authors.affiliation: Trinity Centre for Bioengineering, Trinity Biomedical Sciences Institute, Trinity College Dublin, Ireland.|Department of Mechanical and Manufacturing Engineering, School of Engineering, Trinity College Dublin, Ireland.
authors.forename: Tariq
authors.initials: T
authors.lastname: Mesallati
authors.affiliation: Trinity Centre for Bioengineering, Trinity Biomedical Sciences Institute, Trinity College Dublin, Ireland.|Department of Mechanical and Manufacturing Engineering, School of Engineering, Trinity College Dublin, Ireland.
authors.forename: Conor T
authors.initials: CT
authors.lastname: Buckley
authors.affiliation: Trinity Centre for Bioengineering, Trinity Biomedical Sciences Institute, Trinity College Dublin, Ireland.|Department of Mechanical and Manufacturing Engineering, School of Engineering, Trinity College Dublin, Ireland.|Advanced Materials and Bioengineering Research Centre (AMBER), Trinity College Dublin and the Royal College of Surgeons in Ireland, Ireland.
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Kelly
mesh_terms: D000818:Animals; D002356:Cartilage / Q000166:cytology / Q000378:metabolism*; D019902:Chondrocytes / Q000166:cytology / Q000378:metabolism*; D018920:Coculture Techniques; D020100:Hydrogels / Q000737:chemistry*; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000378:metabolism*; D013552:Swine; D023822:Tissue Engineering
chemical_list: D020100:Hydrogels
keywords: agarose hydrogel; bone marrow-derived mesenchymal stem cells; cartilage; infrapatellar fat pad-derived stem cells; mixed co-culture; self-assembly; structured co-culture