Experiment Begins on Cardiac Treatment with iPS Cells by Japanese Innovative Enterprise
In a groundbreaking development, Japanese startup iHeart Japan Corp. has successfully conducted a clinical trial to transplant a regenerative treatment sheet containing cardiac muscle cells derived from human induced pluripotent stem (iPS) cells into a patient with dilated cardiomyopathy.
The surgery was performed at the Tokyo Women's Medical University Hospital at the end of May 2025. The patient, who had been suffering from dilated cardiomyopathy, has since been discharged and is currently under monitoring for safety and efficacy assessment.
Key details of the treatment reveal that the sheet, which is about 4 cm in diameter and 1 mm thick, was created by layering three types of cells, including cardiac muscle cells and blood vessel cells, with gelatin particles to form the structure. When applied to the heart's surface, the sheet is expected to improve heart contractions partly through exosomes (cell-produced vesicles).
iHeart Japan plans to first confirm the safety of the treatment with three patients who receive the sheet, then gradually expand to up to 10 patients by the end of 2027. Based on clinical results, the startup aims to seek regulatory approval for commercial manufacturing and sales.
This trial marks an important step as one of the earliest uses of iPS cell–derived cardiac tissue sheets in humans, demonstrating initial safety and moving toward proving efficacy in treating heart muscle diseases such as dilated cardiomyopathy.
Parallel to this development, other Japanese groups are also conducting iPS cell-based cardiac regenerative therapies, including injection of cardiac spheroids and applications for Ministry of Health approval for iPS-derived myocardial cell treatments.
This approach builds on earlier foundational work that developed differentiation methods to produce beating cardiac muscle cells from iPS cells, enabling regenerative medicine applications in cardiology.
The treatment sheet produced by iHeart Japan Corp. contains exosomes, vesicles produced by cells. The patient received a treatment derived from human iPS cells. The dimensions of the treatment sheet were not previously mentioned. The treatment sheet was designed to function partially through the actions of exosomes and was intended to be placed on the surface of the heart.
The startup, based in the western city of Kyoto, Japan, has its sights set on expanding the trials and seeking regulatory approvals in the coming years. This promising development in regenerative medicine offers hope for those suffering from heart muscle diseases.
[1] Source: iHeart Japan Corp. Press Release, May 2025. [2] Source: Tokyo Women's Medical University Hospital News, May 2025. [3] Source: Nature Medicine, January 2023.
Science has advanced with the use of human induced pluripotent stem (iPS) cells to create a regenerative treatment sheet for medical-conditions such as dilated cardiomyopathy. This health-and-wellness innovation, produced by iHeart Japan Corp., was recently tested on a patient at Tokyo Women's Medical University Hospital, offering hope for those suffering from heart muscle diseases.
