Optimizing nutrient channel spacing and revisiting TGF-beta in large engineered cartilage constructs

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• 作者：Alexander D. Cigan ; Robert J. Nims ; Gordana Vunjak-Novakovic ; Clark T. Hung ; Gerard A. Ateshian ; ^{ateshian@columbia.edu" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Tissue engineering ; Cartilage ; Agarose ; Chondrocytes ; Nutrient transport ; Growth factors
• 刊名：Journal of Biomechanics
• 出版年：2016
• 出版时间：5 July 2016
• 年：2016
• 卷：49
• 期：10
• 页码：2089-2094
• 全文大小：1849 K

文摘

Cartilage tissue engineering is a promising approach to treat osteoarthritis. However, current techniques produce tissues too small for clinical relevance. Increasingly close-packed channels have helped overcome nutrient transport limitations in centimeter-sized chondrocyte-agarose constructs, yet optimal channel spacings to recapitulate native cartilage compositional and mechanical properties in constructs this large have not been identified. Transient active TGF-β treatment consistently reproduces native compressive Young׳s modulus (E_Y) and glycosaminoglycan (GAG) content in constructs, but standard dosages of 10 ng/mL exacerbate matrix heterogeneity. To ultimately produce articular layer-sized constructs, we must first optimize channel spacing and investigate the role of TGF-β in the utility of channels. We cultured ∅10 mm constructs with 0, 12, 19, or 27 nutrient channels (∅1 mm) for 6–8 weeks with 0, 1, or 10 ng/mL TGF-β; subsequently we analyzed them mechanically, biochemically, and histologically. Constructs with 12 or 19 channels grew the most favorably, reaching E_Y=344±113 kPa and GAG and collagen contents of 10.8±1.2% and 2.2±0.2% of construct wet weight, respectively. Constructs with 27 channels had significantly less deposited GAG than other groups. Channeled constructs given 1 or 10 ng/mL TGF-β developed similar properties. Without TGF-β, constructs with 0 or 12 channels exhibited properties that were indistinguishable, and lower than TGF-β-supplemented constructs. Taken together, these results emphasize that nutrient channels are effective only in the presence of TGF-β, and indicate that spacings equivalent to 12 channels in ∅10 mm constructs can be employed in articular-layer-sized constructs with reduced dosages of TGF-β.