In cardiovascular medicine, severe heart conditions such as dilated cardiomyopathy are often considered among the most difficult to treat. As heart muscle progressively loses its ability to contract, the traditional options of last resort are often highly invasive open-heart surgery, or a heart transplant that may never become available in time. On June 12, 2026, Shinshu University School of Medicine's affiliated hospital in Japan, together with a related medical startup, held a press conference announcing the world's first successful clinical trial transplanting iPS cell-derived cardiomyocytes via a vascular catheter — sparing the patient the trauma of open-heart surgery, with the entire cell transplant completed through a slender catheter.
From Open-Chest Patches to Minimally Invasive Intervention
Japan had previously approved ReHeart, the world's first iPS cardiomyocyte sheet therapy — but that approach still required opening the chest to apply the cell sheet to the surface of the heart. This new "catheter transplant method," developed by the Shinshu University team, dramatically reduces surgical trauma: the research team first differentiates and cultures iPS cells into highly viable cardiomyocytes, processed into tiny spherical cell clusters; the surgeon doesn't need to open the chest at all — instead, a slender catheter is inserted through a blood vessel near the patient's groin and guided into the heart; the cell clusters are then injected directly through the catheter into the damaged heart muscle tissue, where they integrate with the existing heart tissue and work together to help restore the heart's contractile function.
The First Patient: In Their 70s, with Improved Cardiac Function After the Procedure
This world-first clinical trial formally began in March 2026, with the first participant a man in his 70s with dilated cardiomyopathy, for whom conventional open-heart surgery carried significant risk due to his age and physical condition. Post-procedure follow-up showed no serious complications; one month after the procedure, all of the patient's core cardiac function indicators showed a clear trend of improvement. The project team noted that such short-term improvement in cardiac function indicators is relatively uncommon with other conventional treatment approaches.
Future Plans: Expanding the Clinical Trial Within Three Years
According to the project's announced roadmap, the company and hospital plan to perform this catheter transplant procedure on a total of 14 patients with severe cardiomyopathy over the next three years, systematically building up long-term safety and efficacy data to lay the groundwork for a future formal approval application. This technology is especially well suited to elderly, frail, or medically complex patients with severe heart disease who cannot tolerate open-heart surgery.
What We Can Do for You
If you or a family member is facing dilated cardiomyopathy, ischemic cardiomyopathy, or severe heart failure, and conventional open-heart surgery isn't an option due to age or limited physical tolerance, MIZUHO PHARMA can help arrange a remote consultation and treatment assessment with Japan's leading regenerative medicine specialists, along with medical translation and in-person accompaniment services while you're in Japan.