Development of a cardiotoxicity evaluation system using a Heart-on-a-Chip Microdevice with aligned fiber device

Abstract Background and Purpose Cardiovascular cells differentiated from human induced pluripotent stem (iPS) cells, such as cardiomyocytes, are expected to be useful for evaluating cardiac pharmacology and toxicity in humans. In recent years, myocardial damage caused by anticancer drugs has begun to attract attention. Being able to evaluate human cardiotoxicity early in the development of novel drugs like anticancer agents confers advantages in terms of cost and development speed. The aim of this study was to develop a highly sensitive bioassay system that can evaluate the physiological function of the human heart, and to validate the efficacy of the system toward detection of cardiotoxicity of drugs. Methods We differentiated human iPS cells into cardiovascular cells (cardiomyocytes, endothelial cells and mural cells) and applied dynamic culture training to generate vascularized microtissues (VCM) with vascular network structures. By integrating this VCM with a microfluidic chip containing microchannels, we developed a heart-on-a-chip microdevice (HMD) specialized for evaluating cardiac function (Figure 1). Furthermore, through a collaborative study with the Stem Cell & Device Laboratory (SCAD), application of their aligned fiber device improved throughput and stability, allowing development of a SCAD-HMD capable of evaluating longer-term cardiotoxicity. Results SCAD-HMD can quantify physiological parameters of VCM such as ejection volume and force based on displacement of particles within the microchannels. Our results showed that SCAD-HMD not only exhibited pharmacological responses to representative circulatory stimulants, but also reproduced clinical events occurring in actual practice, demonstrating that the anticancer drug trastuzumab, commonly used for breast cancer treatment, causes myocardial disfunction when combined with doxorubicin. Conclusions This study demonstrated that SCAD-HMD can stably evaluate the toxicity of drugs on the human heart. In the future, establishing SCAD-HMD using iPS cells derived from individual patients and assessing responses to specific drugs may enable "individualized cardiotoxicity assessment systems" that can preemptively avoid cardiac complications associated with anticancer drugs and other pharmacological agents.