Researchers Report Two Experiments Growing Human Replacement Organs In Animals.

“Biologists are reporting two significant advances” this week in “replacing a patient’s diseased organs with ones derived from that person’s own cells, and grown in an animal host.” One team of researchers, led by Jun Wu and Juan Carlos Izpisua Belmonte at the Salk Institute, “has shown for the first time that human stem cells can contribute to forming the tissues of a pig, despite the 90 million years of evolution between the two species.” Meanwhile, a second group, led by Tomoyuki Yamaguchi and Hideyuki Sato of the University of Tokyo and Hiromitsu Nakauchi of Stanford, “has reversed diabetes in mice by inserting pancreas glands composed of mouse cells that were grown in a rat.” One report was published in Cell and the other was published in Nature. The AP (1/26, Ritter) reports, “The Salk team is working on making humanized pancreases, hearts and livers in pigs. The animals would grow those organs in place of their own, and they’d be euthanized before the organ is removed.” Scientists “used human stem cells, which are capable of producing a wide variety of specialized cells. They injected pig embryos made in the lab with three to 10 of those cells apiece, and implanted the embryos into sows.” After about three weeks of development, “186 embryos were removed and examined.” The cells “generated the precursors of muscle, heart, pancreas, liver and spinal cord tissue in the embryos.” They said they would test “ways to focus human cells on making specific tissues while avoiding any contribution to the brain, sperm or eggs.” The AP adds, “Ethics experts were also impressed by the results.” http://hosted.ap.org/dynamic/stories/U/US_SCI_PIG_HUMAN_EMBRYOS?SITE=AP&SECTION=HOME&TEMPLATE=DEFAULT