First Surgery Using Commercial Stem Cell-Derived Heart Muscle Sheets Performed in Japan

Ischemic heart disease causes damage when narrowed coronary arteries restrict blood flow to the heart. For patients who have exhausted other treatment options, persistent symptoms, reduced cardiac function, and limited exercise tolerance remain major concerns. Addressing this need, a Japanese hospital has performed the first surgery using commercially available sheets of stem cell-derived heart muscle cells.

At Osaka Keisatsu Hospital (Osaka, Japan), surgeons transplanted the cell sheets into the heart of a woman in her 50s. The operation, performed on September 29, 2026, lasted about an hour. It was the first clinical use of the therapy since it received conditional approval from the Japanese government in March 2026.

The sheets contain heart muscle cells derived from induced pluripotent stem (iPS) cells. These cells are created by returning mature, specialized cells to an earlier developmental state. They can then develop into different cell types. The therapy is intended primarily for heart patients who have exhausted other treatment options.

Trials of the therapy involved eight patients with ischemic heart disease. All eight experienced relief of symptoms, while four also showed improved heart function, according to Japanese media reports. The treatment is expected to improve heart muscle function, heart failure symptoms, cardiac performance, and exercise tolerance, although those broader outcomes have not yet been established.

The team plans to perform similar operations on 75 patients by 2033 and report on the treatment’s efficacy. Full authorization would depend on evidence of benefit and safety gathered over the next seven years. Japan also conditionally approved a separate iPS-cell treatment for Parkinson’s disease in March 2026. That treatment involves transplanting cells into a patient’s brain and was approved following a successful clinical trial.