Science – Last week, a Japanese ethics panel decided that they are, recommending that the government lift a ban on certain experiments that mix human cells with those of other animals. But the scientist who is pioneering this research area and who pushed for an end to the ban, stem cell biologist Hiromitsu Nakauchi of the University of Tokyo, is planning to set up a lab in California, bringing the debate—and the possible benefits—to the United States.
Nakauchi has been pursuing the idea of implanting human pluripotent stem cells into pig embryos genetically engineered to be incapable of developing their own pancreases. These cells could be either embryonic stem cells or, preferably, induced pluripotent stem (iPS) cells. iPS cells derived from a patient’s own skin or other tissue should avoid immune rejection, because the generated organ would genetically match the recipient. If all goes to plan, the stem cells would develop into human pancreases in the pig fetus. (Mouse experiments have shown that pluripotent cells can fill the developmental niche opened by the absence of an organ.) After the piglet’s birth, the pancreas would be harvested and islet cells isolated for transplantation into human type 1 diabetes patients, whose islets either no longer produce insulin or produce too little of the sugar-regulating hormone …. >>Contine Reading<<.