Dynamic compressive loading differentially regulates chondrocyte anabolic and catabolic activity with age

Authors

  • Nikki. L. Farnsworth,

    1. Department of Chemical and Biological Engineering, University of Colorado, 3415 Colorado Avenue, Boulder, Colorado 80303-0596; telephone: 303-735-6714; fax: 303-492-4341
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  • Lorena R. Antunez,

    1. Department of Chemical and Biological Engineering, University of Colorado, 3415 Colorado Avenue, Boulder, Colorado 80303-0596; telephone: 303-735-6714; fax: 303-492-4341
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  • Stephanie J. Bryant

    Corresponding author
    1. Department of Chemical and Biological Engineering, University of Colorado, 3415 Colorado Avenue, Boulder, Colorado 80303-0596; telephone: 303-735-6714; fax: 303-492-4341
    2. BioFrontiers Institute, University of Colorado, Boulder, Colorado
    3. Material Science and Engineering Program, University of Colorado, Boulder, Colorado
    • Department of Chemical and Biological Engineering, University of Colorado, 3415 Colorado Avenue, Boulder, Colorado 80303-0596; telephone: 303-735-6714; fax: 303-492-4341
    Search for more papers by this author

Abstract

Dynamic loading has emerged as an important part of cartilage tissue engineering strategies for enhancing tissue production and producing cartilage with functionally competent mechanical properties. As patients in need of cartilage span a range of age groups, questions arise as to the role of age in a cell's ability to respond to dynamic loading. Therefore, this study's goal was to characterize age-related anabolic and catabolic responses of chondrocytes to dynamic compressive loading. Bovine chondrocytes isolated from juvenile (3-week-old) and adult (2- to 3-year-old) donors were encapsulated in poly(ethylene glycol) hydrogels and subjected to dynamic loading applied intermittently in a sinusoidal waveform at 1 or 0.3 Hz with 5 or 10% amplitude strain up to 2 weeks. Loading significantly enhanced total sulfated glycosaminoglycan (sGAG) production by 220% for juvenile chondrocytes with 0.3 Hz/5% loading and by 88% for adult chondrocytes with 1 Hz/5% loading, while all other loading regimes did not affect or inhibited total sGAG production. Contrarily, deposition of larger matrix molecules of aggrecan and collagen II was either not affected or inhibited by loading. Collagen VI deposition was significantly upregulated by loading but only in adult chondrocytes and under different loading regimes (1 Hz/10% and 0.3 Hz/5%) when compared to total sGAGs. Both cell populations displayed catabolic activity, which appeared to be stimulated by loading. Taken together, findings from this study suggest that loading differentially regulates matrix synthesis and the response is highly dependent on donor age. Biotechnol. Bioeng. 2013; 110: 2046–2057. © 2013 Wiley Periodicals, Inc.

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