Department of Biomedical Engineering, Columbia University, New York, NY 10032, USA.
J Tissue Eng Regen Med. 2012 Nov;6(10):e12-23. doi: 10.1002/term.525. Epub 2011 Dec 13.
Maintenance of normal myocardial function depends intimately on synchronous tissue contraction, driven by electrical activation and on adequate nutrient perfusion in support thereof. Bioreactors have been used to mimic aspects of these factors in vitro to engineer cardiac tissue but, due to design limitations, previous bioreactor systems have yet to simultaneously support nutrient perfusion, electrical stimulation and unconstrained (i.e. not isometric) tissue contraction. To the best of our knowledge, the bioreactor system described herein is the first to integrate these three key factors in concert. We present the design of our bioreactor and characterize its capability in integrated experimental and mathematical modelling studies. We then cultured cardiac cells obtained from neonatal rats in porous, channelled elastomer scaffolds with the simultaneous application of perfusion and electrical stimulation, with controls excluding either one or both of these two conditions. After 8 days of culture, constructs grown with simultaneous perfusion and electrical stimulation exhibited substantially improved functional properties, as evidenced by a significant increase in contraction amplitude (0.23 ± 0.10% vs 0.14 ± 0.05%, 0.13 ± 0.08% or 0.09 ± 0.02% in control constructs grown without stimulation, without perfusion, or either stimulation or perfusion, respectively). Consistently, these constructs had significantly improved DNA contents, cell distribution throughout the scaffold thickness, cardiac protein expression, cell morphology and overall tissue organization compared to control groups. Thus, the simultaneous application of medium perfusion and electrical conditioning enabled by the use of the novel bioreactor system may accelerate the generation of fully functional, clinically sized cardiac tissue constructs.
维持正常心肌功能取决于电激活驱动的同步组织收缩，以及支持其的充足营养灌注。生物反应器已被用于体外模拟这些因素的某些方面，以构建心肌组织，但由于设计限制，以前的生物反应器系统尚未同时支持营养灌注、电刺激和无约束（即非等长）的组织收缩。据我们所知，本文所述的生物反应器系统是第一个协同整合这三个关键因素的系统。我们介绍了我们的生物反应器设计，并在综合实验和数学建模研究中对其功能进行了描述。然后，我们在多孔通道弹性体支架中培养了来自新生大鼠的心脏细胞，同时施加灌注和电刺激，对照实验则排除了这两种条件中的一种或两种。在 8 天的培养后，同时进行灌注和电刺激的构建体表现出显著改善的功能特性，这表现在收缩幅度显著增加（0.23 ± 0.10%与 0.14 ± 0.05%、0.13 ± 0.08%或 0.09 ± 0.02%，分别为对照构建体在无刺激、无灌注或无刺激或无灌注条件下的生长）。一致地，与对照组相比，这些构建体具有显著改善的 DNA 含量、支架厚度内的细胞分布、心脏蛋白表达、细胞形态和整体组织结构。因此，使用新型生物反应器系统同时施加培养基灌注和电调节可以加速具有完全功能的、临床尺寸的心脏组织构建体的生成。
