With the ability to be coaxed into different kinds of mature cell types, induced pluripotent stem cells (iPSCs) hold all kinds of potential in the world of regenerative medicine. One of the many possibilities could be repairing damaged hearts, something that will soon be put to the test for the first time ever in newly approved clinical trials in Japan.

Since emerging from the laboratory of researcher Shinya Yamanaka in Japan in 2006, the potential of iPSCs has been explored in all kinds of promising research efforts. We have seen them implanted into rabbits to restore their vision, become brain tumor predators, and turned into precursor cells for human organs.

IPSCs are created by first harvesting cells from body tissues and then infecting them with a virus, in turn introducing them to carefully selected genes that return them to their immature state. From there they can develop into any cell in the body, a capability so powerful it earned Yamanaka a Nobel Prize in 2012.

Professor Yoshiki Sawa, a cardiac surgeon from Osaka University in Japan, has been developing an IPSC therapy for patients with heart disease. The technique involves using IPSCs to create a sheet of 100 million heart muscle cells and grafting it onto a heart, where they then appear to release growth factors that promote the regeneration of damaged muscle.

The technique was tested on pigs last year and was shown to improve the organ's function, so Sawa promptly submitted a research plan to carry out trials on human patients. That plan has now been conditionally approved by Japan's health ministry. Three people are set to receive the treatment and then be observed over the 12-month period that follows.

This pathway to clinical use is made possible under Japan's fast-track approval system that was introduced in 2014, and not without criticism. The system aimed to increase access to regenerative medicines by introducing laws that allow for emerging treatments to be used so long as they have been proven safe, with only hints of their effectiveness.

The idea is that as patients receive these safe treatments, more conclusive data on their efficacy can be gathered thereafter. This negates the need for large-scale clinical trials that take place over several years and cost hundreds of millions of dollars. But the detractors say this effectively asks patients to foot the bill for clinical trials of unproven drugs. Economics aside, it could also see patients spurn other potentially life-saving treatments, and then there are the inherent risks of undergoing surgery.

In any case, the team will look to follow up this first human trial with a larger clinical trial involving around 10 patients. If all goes to plan on that front, commercial availability may follow.