title: Synthesis rates and binding kinetics of matrix products in engineered cartilage constructs using chondrocyte-seeded agarose gels.
abstract: Large-sized cartilage constructs suffer from inhomogeneous extracellular matrix deposition due to insufficient nutrient availability. Computational models of nutrient consumption and tissue growth can be utilized as an efficient alternative to experimental trials to optimize the culture of large constructs; models require system-specific growth and consumption parameters. To inform models of the [bovine chondrocyte]-[agarose gel] system, total synthesis rate (matrix accumulation rate+matrix release rate) and matrix retention fractions of glycosaminoglycans (GAG), collagen, and cartilage oligomeric matrix protein (COMP) were measured either in the presence (continuous or transient) or absence of TGF-β3 supplementation. TGF-β3's influences on pyridinoline content and mechanical properties were also measured. Reversible binding kinetic parameters were characterized using computational models. Based on our recent nutrient supplementation work, we measured glucose consumption and critical glucose concentration for tissue growth to computationally simulate the culture of a human patella-sized tissue construct, reproducing the experiment of Hung et al. (2003). Transient TGF-β3 produced the highest GAG synthesis rate, highest GAG retention ratio, and the highest binding affinity; collagen synthesis was elevated in TGF-β3 supplementation groups over control, with the highest binding affinity observed in the transient supplementation group; both COMP synthesis and retention were lower than those for GAG and collagen. These results informed the modeling of GAG deposition within a large patella construct; this computational example was similar to the previous experimental results without further adjustments to modeling parameters. These results suggest that these nutrient consumption and matrix synthesis models are an attractive alternative for optimizing the culture of large-sized constructs.
authors.affiliation: Department of Biomedical Engineering, Columbia University, 1210 Amsterdam Avenue, MC 8904, 351 Engineering Terrace, New York, NY 10027, USA.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Nims
authors.affiliation: Department of Biomedical Engineering, Columbia University, 1210 Amsterdam Avenue, MC 8904, 351 Engineering Terrace, New York, NY 10027, USA.
authors.forename: Alexander D
authors.initials: AD
authors.lastname: Cigan
authors.affiliation: Department of Mechanical Engineering, Columbia University, 500 West 120th Street, MC 4703, 220 Mudd, New York, NY 10027, USA.
authors.forename: Michael B
authors.initials: MB
authors.lastname: Albro
authors.affiliation: Department of Biomedical Engineering, Columbia University, 1210 Amsterdam Avenue, MC 8904, 351 Engineering Terrace, New York, NY 10027, USA.
authors.forename: Clark T
authors.initials: CT
authors.lastname: Hung
authors.affiliation: Department of Biomedical Engineering, Columbia University, 1210 Amsterdam Avenue, MC 8904, 351 Engineering Terrace, New York, NY 10027, USA; Department of Mechanical Engineering, Columbia University, 500 West 120th Street, MC 4703, 220 Mudd, New York, NY 10027, USA. Electronic address: ateshian@columbia.edu.
authors.forename: Gerard A
authors.initials: GA
authors.lastname: Ateshian
mesh_terms: D000818:Animals; D002356:Cartilage / Q000502:physiology*; D064236:Cartilage Oligomeric Matrix Protein / Q000378:metabolism; D002417:Cattle; D002478:Cells, Cultured; D019902:Chondrocytes; D003094:Collagen / Q000378:metabolism; D005109:Extracellular Matrix / Q000378:metabolism*; D005782:Gels; D005947:Glucose / Q000378:metabolism; D006025:Glycosaminoglycans / Q000378:metabolism; D007700:Kinetics; D008954:Models, Biological; D012685:Sepharose; D023822:Tissue Engineering; D053782:Transforming Growth Factor beta3 / Q000494:pharmacology
chemical_list: D064236:Cartilage Oligomeric Matrix Protein; D005782:Gels; D006025:Glycosaminoglycans; D053782:Transforming Growth Factor beta3; D003094:Collagen; D012685:Sepharose; D005947:Glucose
keywords: Anatomical models; Cartilage; Extracellular matrix; Growth; Tissue engineering