Photo/IllutrationOsaka University professor Yoshiki Sawa, second from right, explains the clinical study in a news conference held in the university’s Tokyo Office in Chiyoda Ward on May 16. (Satoru Semba)

  • Photo/Illustraion

A team of doctors got the go-ahead May 16 to carry out the world’s first clinical study for heart failure treatment using sheets of cardiac muscle created from induced pluripotent stem (iPS) cells.

The Osaka University team plans to convert the iPS cells into thin cardiac muscle cell sheets and transplant them into the hearts of patients.

The first transplant will likely be performed as early as this fiscal year, which ends next March.

“I have high hopes that this new treatment will prevent heart failure from becoming serious," said Yoshiki Sawa, a professor of cardiovascular surgery at the university and head of the group. "That has been my longstanding dream.”

Sawa gave a news conference after winning approval for the procedure from a panel of the health ministry.

The three patients who will take part in the clinical study suffer from ischemic cardiomyopathy, or clogged blood vessels. This stalls blood flow to the heart, damaging the organ's muscles.

The sheets are expected to improve blood flow, and thus heart function. The group will monitor the method's safety and effectiveness by noting any changes to heart functions over the course of a year.

The health ministry panel attached a condition to the clinical study, calling on the group to modify certain sentences in documents given to the patients to explain the possible risks involved in the clinical trial.

In 2016, Tokyo-based medical equipment maker Terumo Corp. began selling “Heart Sheet,” which has the same functions as the cell sheets to be transplanted by the Osaka University group.

However, Terumo’s products are made from cells taken from patients’ leg muscles, unlike the sheets that the Osaka University group will use.

The Osaka group's sheets have proved more effective than Terumo’s products in animal tests.

Heart disease is the second most common cause of death in Japan after cancer. Heart disease patients across Japan are thought to number in the several tens of thousands.

Some of them will need heart transplants in the future. However, patients aged 65 or older are, in principle, not eligible for heart transplants.

If the clinical trial is a success, many lives could be saved.

“As this is still new technology, we can’t allow ourselves to place excessive expectations on it right now,” said Tooru Masuyama, a professor of cardiovascular internal medicine at Hyogo College of Medicine.

“But it is reasonable to conclude that if the sheets are transplanted into patients before their heart condition becomes serious, their health should improve,” he added.

In 2014, researchers at Riken, a government-affiliated research institute, and other organizations used iPS cells to treat a patient with age-related macular degeneration, an intractable disease that affects vision.

It was the first time iPS cells had been used in medical treatment.

Experts pointed out that using iPS cells to treat heart disease is much more difficult than applying the same technology to correct vision problems.

In the case of eye disease, about 250,000 cells are transplanted. Heart failure, on the other hand, requires about 100 million cells to be transplanted.

If iPS cells don't properly morph into heart muscle cells or cause changes to cells for other parts of the body, they could induce tumors.

“The more cells that are transplanted, the higher the risk. The doctors in this clinical study will have to proceed very cautiously,” said Akifumi Matsuyama, a professor of regenerative medicine at Fujita Health University and a member of the health ministry’s panel.