After sharing the Nobel Prize for Medicine for his research work on 8 October with John Gurdon, the Japanese researcher Shinya Yamanaka stated in an interview with AFP [Agence France Presse] that “the principle of reprogramming [adult cells] is finally very simple, by using three or four genes to convert for example one adult skin cell into an iPS cell that is malleable like an embryonic cell."
To the question of the journalist whether "this reprogramming technique used in 2006 on mouse cells and then in 2007 on human cells is the answer to the ethical problems raised by the use of human embryos for work on stem cells," the Japanese researcher explained: "Now we can avoid the use of human embryos, so it’s good. However, we are facing new ethical issues. For example, we can make reproductive sperm or oocyte cells from skin or blood, passing through the iPS stage. It is a new ethical issue: can we make sperm from blood and can we fertilise these oocytes (eggs)?" he asked. "We really need discussion in society about how much we can do with this new technology."
Pointing out that he had "realised from the beginning the ethical implication", i.e. in 2006, he added that initially, "in terms of medical applications, [he thought that] this technology would be used mainly for regenerative medicine [i.e. to repair a damaged organ] […]. But soon afterwards, [he] realised that this technology had a greater potential for discovering new medications."
When asked about the use of iPS cells IPS for tests on humans, Shinya Yamanaka pointed out that these would be carried out soon: "scientists in Kobe had already applied to the Japanese authorities for permission to carry out the world’s first iPS trial on humans, using cells on patients suffering from retinal disease.”
Lastly, when asked about the Japanese project to set up a bank of iPS stem cells, a project approved in July, the Japanese researcher replied: "In theory, we can make iPS cells from each patient. But it would be very expensive” and would take too long. He spoke about the alternative: "A stem cell bank would be a good alternative. The idea is to choose donors whose DNA profile is least likely to trigger rejection by a patient’s immune system. We may be able to cover many patients by having only a handful of iPS stock, that’s our plan," he said. "By our estimations, we identified 140 such specific donors, (and with these) we could cover up to 90 percent of the whole population [of Japan]."