Abstract：
Human heart tissues grown as three-dimensional spheroids and consisting of different cardiac cell types derived from pluripotent stem cells (hiPSCs) recapitulate aspects of human physiology better than standard two-dimensional models in vitro. They typically consist of less than 5000 cells and are used to measure contraction kinetics although not contraction force. By contrast, engineered heart tissues (EHTs) formed around two flexible pillars, can measure contraction force but conventional EHTs often require between 0.5 and 2 million cells. This makes large-scale screening of many EHTs costly. Our goals here were (i) to create a physiologically relevant model that required fewer cells than standard EHTs making them less expensive, and (ii) to ensure that this miniaturized model retained correct functionality. We demonstrated that fully functional EHTs could be generated from physiologically relevant combinations of hiPSC-derived cardiomyocytes (70%), cardiac fibroblasts (15%) and cardiac endothelial cells (15%), using as few as 1.6 × 104 cells. Our results showed that these EHTs were viable and functional up to 14 days after formation. The EHTs could be electrically paced in the frequency range between 0.6 and 3 Hz, with the optimum between 0.6 and 2 Hz. This was consistent across three downscaled EHT sizes tested. These findings suggest that miniaturized EHTs could represent a cost-effective microphysiological system for disease modelling and examining drug responses particularly in secondary screens for drug discovery.
摘要：
人类心脏组织生长为三维球体，并由源自多能干细胞（hiPSC）的不同心脏细胞类型组成，在体外比标准二维模型更好地概括了人类生理学的各个方面。它们通常由少于5000个细胞组成，用于测量收缩动力学，尽管不是收缩力。相比之下,围绕两个柔性支柱形成的工程心脏组织（EHTs），可以测量收缩力，但传统的EHT通常需要0.5到2百万个细胞。这使得许多EHTs的大规模筛选成本很高。我们在这里的目标是（i）创建一个生理相关的模型，需要比标准EHTs更少的细胞，使它们更便宜，和(ii)确保该小型化模型保持正确的功能。我们证明，完全功能的EHTs可以从生理相关的组合产生hiPSC衍生的心肌细胞（70％），心脏成纤维细胞（15％）和心脏内皮细胞（15％），使用少至1.6×104个细胞。我们的结果表明，这些EHTs在形成后14天内都是可行的和起作用的。EHT可以在0.6和3Hz之间的频率范围内进行电起搏，最佳在0.6和2Hz之间。这在测试的三个缩小的EHT尺寸之间是一致的。这些发现表明，小型化的EHT可以代表一种经济有效的微生理系统，用于疾病建模和检查药物反应，特别是在用于发现药物的二次筛选中。
