title: Growth factor stimulation improves the structure and properties of scaffold-free engineered auricular cartilage constructs.
abstract: The reconstruction of the external ear to correct congenital deformities or repair following trauma remains a significant challenge in reconstructive surgery. Previously, we have developed a novel approach to create scaffold-free, tissue engineering elastic cartilage constructs directly from a small population of donor cells. Although the developed constructs appeared to adopt the structural appearance of native auricular cartilage, the constructs displayed limited expression and poor localization of elastin. In the present study, the effect of growth factor supplementation (insulin, IGF-1, or TGF-β1) was investigated to stimulate elastogenesis as well as to improve overall tissue formation. Using rabbit auricular chondrocytes, bioreactor-cultivated constructs supplemented with either insulin or IGF-1 displayed increased deposition of cartilaginous ECM, improved mechanical properties, and thicknesses comparable to native auricular cartilage after 4 weeks of growth. Similarly, growth factor supplementation resulted in increased expression and improved localization of elastin, primarily restricted within the cartilaginous region of the tissue construct. Additional studies were conducted to determine whether scaffold-free engineered auricular cartilage constructs could be developed in the 3D shape of the external ear. Isolated auricular chondrocytes were grown in rapid-prototyped tissue culture molds with additional insulin or IGF-1 supplementation during bioreactor cultivation. Using this approach, the developed tissue constructs were flexible and had a 3D shape in very good agreement to the culture mold (average error <400 µm). While scaffold-free, engineered auricular cartilage constructs can be created with both the appropriate tissue structure and 3D shape of the external ear, future studies will be aimed assessing potential changes in construct shape and properties after subcutaneous implantation.
authors.affiliation: Human Mobility Research Centre, Kingston General Hospital and Queen's University, Kingston, Canada; Department of Histology and Embryology, Institute of Biology, University of Campinas (UNICAMP), Campinas, Brazil.
authors.forename: Renata G
authors.initials: RG
authors.lastname: Rosa
authors.affiliation: Department of Histology and Embryology, Institute of Biology, University of Campinas (UNICAMP), Campinas, Brazil.
authors.forename: Paulo P
authors.initials: PP
authors.lastname: Joazeiro
authors.affiliation: Human Mobility Research Centre, Kingston General Hospital and Queen's University, Kingston, Canada; Department of Histology and Embryology, Institute of Biology, University of Campinas (UNICAMP), Campinas, Brazil.
authors.forename: Juares
authors.initials: J
authors.lastname: Bianco
authors.affiliation: Human Mobility Research Centre, Kingston General Hospital and Queen's University, Kingston, Canada; School of Computing, Queen's University, Kingston, Canada.
authors.forename: Manuela
authors.initials: M
authors.lastname: Kunz
authors.affiliation: Human Mobility Research Centre, Kingston General Hospital and Queen's University, Kingston, Canada; Department of Mechanical & Materials Engineering, Queen's University, Kingston, Canada.
authors.forename: Joanna F
authors.initials: JF
authors.lastname: Weber
authors.affiliation: Human Mobility Research Centre, Kingston General Hospital and Queen's University, Kingston, Canada; Department of Chemical Engineering, Ryerson University, Toronto, Canada; Keenan Research Centre of the Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Canada.
authors.forename: Stephen D
authors.initials: SD
authors.lastname: Waldman
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D002478:Cells, Cultured; D019902:Chondrocytes / Q000502:physiology*; D003094:Collagen / Q000378:metabolism; D004425:Ear Cartilage / Q000166:cytology; D004549:Elastin / Q000378:metabolism; D005260:Female; D007328:Insulin / Q000502:physiology; D007334:Insulin-Like Growth Factor I / Q000502:physiology*; D011817:Rabbits; D023822:Tissue Engineering; D054457:Tissue Scaffolds
chemical_list: D007328:Insulin; D007334:Insulin-Like Growth Factor I; D003094:Collagen; D004549:Elastin