International Centre for Genetic Engineering and Biotechnology, Trieste, Italy.
ACS Nano. 2013 Jul 23;7(7):5746-56. doi: 10.1021/nn4002193. Epub 2013 Jun 11.
Myocardial tissue engineering currently represents one of the most realistic strategies for cardiac repair. We have recently discovered the ability of carbon nanotube scaffolds to promote cell division and maturation in cardiomyocytes. Here, we test the hypothesis that carbon nanotube scaffolds promote cardiomyocyte growth and maturation by altering the gene expression program, implementing the cell electrophysiological properties and improving networking and maturation of functional syncytia. In our study, we combine microscopy, biological and electrophysiological methodologies, and calcium imaging, to verify whether neonatal rat ventricular myocytes cultured on substrates of multiwall carbon nanotubes acquire a physiologically more mature phenotype compared to control (gelatin). We show that the carbon nanotube substrate stimulates the induction of a gene expression profile characteristic of terminal differentiation and physiological growth, with a 2-fold increase of α-myosin heavy chain (P < 0.001) and upregulation of sarcoplasmic reticulum Ca(2+) ATPase 2a. In contrast, markers of pathological hypertrophy remain unchanged (β-myosin heavy chain, skeletal α-actin, atrial natriuretic peptide). These modifications are paralleled by an increase of connexin-43 gene expression, gap junctions and functional syncytia. Moreover, carbon nanotubes appear to exert a protective effect against the pathologic stimulus of phenylephrine. Finally, cardiomyocytes on carbon nanotubes demonstrate a more mature electrophysiological phenotype of syncytia and intracellular calcium signaling. Thus, carbon nanotubes interacting with cardiomyocytes have the ability to promote physiological growth and functional maturation. These properties are unique in the current vexing field of tissue engineering, and offer unprecedented perspectives in the development of innovative therapies for cardiac repair.
心肌组织工程目前代表了心脏修复最具现实意义的策略之一。我们最近发现碳纳米管支架能够促进心肌细胞的细胞分裂和成熟。在这里，我们通过改变基因表达程序、实施细胞电生理特性以及改善功能性合胞体的网络和成熟度来检验碳纳米管支架通过促进心肌细胞生长和成熟的假设。在我们的研究中，我们结合显微镜、生物和电生理方法以及钙成像，验证了在多壁碳纳米管基底上培养的新生大鼠心室肌细胞是否比对照（明胶）获得了更具生理成熟表型的特性。我们表明，碳纳米管基底刺激了特征性的终末分化和生理生长的基因表达谱的诱导，α-肌球蛋白重链增加了 2 倍（P < 0.001），肌浆网 Ca(2+)ATP 酶 2a 上调。相比之下，病理性肥大的标志物保持不变（β-肌球蛋白重链、骨骼肌α-肌动蛋白、心钠肽）。这些变化与连接蛋白 43 基因表达、缝隙连接和功能性合胞体的增加相平行。此外，碳纳米管似乎对苯肾上腺素的病理性刺激具有保护作用。最后，碳纳米管上的心肌细胞表现出更成熟的合胞体电生理表型和细胞内钙信号。因此，与心肌细胞相互作用的碳纳米管具有促进生理生长和功能成熟的能力。这些特性在当前令人困扰的组织工程领域是独特的，并为心脏修复的创新疗法的发展提供了前所未有的前景。
