The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA.
Tissue Eng Part A. 2011 Aug;17(15-16):2025-35. doi: 10.1089/ten.TEA.2010.0415. Epub 2011 May 11.
Achievement of viable engineered tissues through in vitro cultivation in bioreactor systems requires a thorough understanding of the complex interplay between hydrodynamic forces and biochemical cues such as serum. To this end, chondrocyte-seeded constructs were cultured under continuous fluid-induced shear forces with reduced serum content (0%-2%, v/v), which was partially or completely replaced by a potential substitute, insulin-transferrin-selenium, to minimize deleterious effects associated with the use of culture media containing high levels of serum (10%-20%). Low-serum cultures yielded constructs with similar biochemical properties to those cultivated with high-serum supplements, whereas the serum-free constructs exhibited poor cell proliferation, insufficient extracellular matrix production, and rapid degradation of and/or shear-induced damage to polyglycolic acid scaffolds. A fibrous outer capsule typically observed in hydrodynamic cultures and characterized by increased cell density and decreased (virtually none) glycosaminoglycan deposition was eliminated when serum concentration was equal to or <0.2% in the presence of hydrodynamic stimuli. Our findings suggest that serum is a requirement in insulin-transferrin-selenium-supplemented cultures in order for constructs to exhibit improved properties in response to hydrodynamic forces, and that mechanical and biochemical stimuli may synergistically modulate tissue properties and morphology through shear-responsive signals.
通过在生物反应器系统中进行体外培养来实现可行的工程化组织，需要深入了解流体力和生化线索（如血清）之间的复杂相互作用。为此，在减少血清含量（0%-2%，体积/体积）的情况下，对软骨细胞接种构建体进行连续流体诱导剪切力下的培养，部分或完全用潜在替代品胰岛素-转铁蛋白-硒替代，以最大程度地减少与使用含有高浓度血清（10%-20%）的培养基相关的有害影响。低血清培养物产生的构建体具有与高血清补充培养物相似的生化特性，而无血清培养物表现出较差的细胞增殖、不足的细胞外基质产生，以及聚乙醇酸支架的快速降解和/或剪切诱导损伤。当存在流体动力刺激时，当血清浓度等于或<0.2%时，在流体力培养中通常观察到的纤维状外壳被消除，其特征是细胞密度增加和糖胺聚糖沉积减少（几乎没有）。我们的发现表明，在胰岛素-转铁蛋白-硒补充培养物中，血清是必需的，以便构建体在响应流体力时表现出改善的特性，并且机械和生化刺激可能通过剪切响应信号协同调节组织特性和形态。
