KYOTO -- A team of Japanese doctors last week performed landmark surgery that transplanted stocked, donated induced pluripotent stem, or iPS cells, into a patient with an intractable eye disease.
If successful, the surgery at Kobe City Medical Center General Hospital, performed under a joint project also involving researchers from Riken and Kyoto University's Center for iPS Cell Research and Application, or CiRA, will pave the way for wider use of regenerative treatment.
The new method is expected to cut the costs and time required to prepare for such surgery to a tenth of exitsting methods.
CiRA head Shinya Yamanaka, who won the Nobel Prize for discovering iPS cells, said he hopes the operation will prove a breakthrough in making the treatment more widely available.
Q: Can you tell us what effect the use of stored, donor-derived iPS cells will have on the proliferation of regenerative treatment?
A: I think that the possibility of regenerative treatment using iPS cells has started to grow in earnest. In 2014, researchers from Riken and other institutions created iPS cells from the patient's cells and transplanted them back into the patient. But this method is costly and time-consuming, so using it more broadly is difficult in terms of medical treatment. If you can create from donor iPS cells and store them, you can use them in multiple patients, and save the costs and time required to grow cultures of them.
The previous procedure was the first example of regenerative treatment using iPS cells, and was tried on one patient. This time, multiple patients are slated to undergo [iPS cell] transplant. After data is collected on these cases, researchers can perform a detailed analysis of the safety and efficacy of the treatment in arresting deterioration of the patients' eyesight, for example.
Q: What do you think are key issues for the spread of regenerative medicine?
A: First of all, safety must be ascertained. This is because there is risk that the graft of cells or organs from someone else's body, rather than from one's own, may be rejected by the patient's immune system. The researchers this time screened iPS cells for immunity types that reduce the risk of rejection. If the immunity type of the iPS cells used in the transplant matches that of the patient to a certain degree, that will reduce the possibility of rejection. It is also important to monitor and make sure that the graft does not grow into cancer cells.
Q: What treatment-research projects using iPS cells are currently being pursued?
A: Starting in the 2018 academic year or later, Kyoto University plans to treat patients of Parkinson's disease, an intractable nerve disease that causes patients' hands and feet to shake, and a blood-related disease that stops blood from clotting. Keio University aims to treat damaged spinal cords, while Osaka University is focusing on heart-failure treatment. There are also plans for cancer and kidney disease treatment. One thing to note is that the rejection risk differs depending on the organ or tissue to undergo treatment. There is also a higher risk for transplanted cells to grow into cancer cells when a large number are transplanted. By contrast, transplants on eyes (like the latest surgery) are less prone to rejection, and the number of transplanted cells is small. So you cannot talk about these cases as if they are similar [to the latest surgery].
Q: How is stocking large amounts of iPS cells important to regenerative treatment?
A: In order for treatment using iPS cells to be used on many people, you need to secure a pool of iPS cells of many immunity types so that you can reduce the risk of rejection. Kyoto University has been working to increase its stock of iPS cells for treatment. If there were just 10 types of necessary cells, it would be able to handle them on its own, but if we establish we need to stock something like 100 types in the future, then the load of managing them will increase significantly.
In order to create high-quality iPS cells, we started a project in January to build a quality control system with cooperation from Takara Bio. But we do not think that working with a business alone will necessarily reduce costs. We create iPS cells from blood donors with good intentions. In that sense, I have reservations about working with a profit-driven company.
Interviewed by Nikkei staff writer Takuro Kusashio