TOKYO -- A health ministry task force conditionally approved a plan May 16 by an Osaka University team to carry out the world's first clinical study treating serious cases of heart failure with sheets of heart muscle cells created from induced pluripotent stem (iPS) cells.
The health minister is expected to issue a notice approving the research in the near future, and patient transplants could begin as early as this year.
The university team led by professor Yoshiki Sawa, a specialist in cardiovascular surgery, had applied in March to carry out the research. The conditions include tough restrictions on the selection of study subjects.
This is the third case of clinical research involving transplants using iPS cells to be approved. In the previous two cases, groups including the Riken research institute are transplanting several hundred thousand cells in the treatment of intractable diseases. The number of cells in the latest research is far greater -- at around 100 million. As there is a risk of iPS cells turning cancerous, it will be crucial for researchers to guarantee the safety of the process.
The approved plan will cover patients with ischemic cardiomyopathy, or hearts weakened by narrowed or blocked arteries preventing blood from reaching parts of the heart muscle. Three people aged between 18 and 79 will have two round cell sheets made from the iPS cells of other people attached to the surface of their hearts. The sheets will each be 0.05 millimeters thick and several centimeters in diameter. Researchers will examine the safety of the procedure, checking for cancer, immunorejection and other such signs, and will also observe changes in the function of the patients' hearts.
The experiments will use cells stocked at Kyoto University's Center for iPS Cell Research and Application. The cell sheets are expected to disappear within three months when the cells die. Administration of immunosuppressant drugs will then be reduced in stages. In experiments on animals, improvement of heart function even after the sheets have disappeared has been confirmed, researchers say.
The research team has already developed cardiac muscle cell sheets using muscle cells from patients' own legs, which in 2015 received conditional approval from the government as tissue-engineered medical products. It is thought that protein released by the sheets improves heart function. It is hoped that iPS cells will prove more effective.
(Japanese original by Suzuko Araki and Momoko Suda, Science and Environment News Department)