title: Glucose concentration and medium volume influence cell viability and glycosaminoglycan synthesis in chondrocyte-seeded alginate constructs.
abstract: Increasing the thickness of tissue-engineered cartilage is associated with loss of chondrocyte viability and biosynthetic activity at the tissue center. Exceptionally high volumes of culture medium, however, can maintain cellularity and glycosaminoglycan synthesis throughout 4-mm-thick constructs. We hypothesized that glucose supplementation could replicate the augmentation of tissue formation achieved by medium volume. Chondrocyte-alginate constructs (40x10(6) cells/mL) were cultured for 14 days in 0.4-6.4 mL/10(-6) cells of either low- (5.1 mM) or high- (20.4 mM) glucose medium. Glucose was critical to chondrocyte viability, and glucose uptake increased significantly (P < .001) with both medium volume and glucose supplementation. After 14 days, constructs cultured in 0.4 mL/10(-6) cells of low-glucose medium had a mass of 172 +/- 6.1 mg and glycosaminoglycan (GAG) content of 0.32 +/- 0.03 mg (mean +/- standard deviation). A 4-fold increase in medium volume increased the final construct mass by 44% and GAG content by 207%. An equivalent increase in glucose supply in the absence of volume change increased these parameters by just 10% and 73%, respectively. A similar trend was observed from 0.8 to 3.2 mL/10(-6) cells, when maximal values of construct GAG content and mass were obtained. Therefore, medium volume remains an important consideration for the optimal culture of tissue-engineered cartilage.
authors.affiliation: Medical Engineering Division and IRC in Biomedical Materials, Department of Engineering, Queen Mary University of London, London, UK.
authors.forename: Hannah K
authors.initials: HK
authors.lastname: Heywood
authors.forename: Dan L
authors.initials: DL
authors.lastname: Bader
authors.forename: David A
authors.initials: DA
authors.lastname: Lee
mesh_terms: D000464:Alginates; D000818:Animals; D002358:Cartilage, Articular / Q000166:cytology / Q000378:metabolism*; D002417:Cattle; D002470:Cell Survival / Q000502:physiology; D002478:Cells, Cultured; D019902:Chondrocytes / Q000166:cytology / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism* / Q000502:physiology; D006025:Glycosaminoglycans / Q000096:biosynthesis*; D023822:Tissue Engineering
chemical_list: D000464:Alginates; D006025:Glycosaminoglycans; D005947:Glucose