Shoukhrat Mitalipov of the Oregon Health & Science University, who led the research, said the success came not from a single technical innovation, but from revising a series of steps in the process. Therapeutic cloning, or somatic-cell nuclear transfer (SCNT), begins with the same process used to create Dolly, the famous cloned sheep, in 1996. The cells are then harvested and cultured to create a stable cell line that is genetically matched to the donor and that can become almost any cell type in the human body. Scientists have tried to get stem cells from cloned human embryos for about a decade, but they've failed. In 2004, a South Korean scientist claimed to have gotten stem cells from cloned human embryos, but that turned out to be a fraud. Their first cell lines were created using fetal skin cells; others were derived using donor cells from an 8-month-old patient with a rare metabolic disorder called Leigh syndrome, to prove that ESCs could be made from more mature donor cells. Dr. George Daley, a stem cell expert at Children's Hospital Boston who didn't participate in the work, called the new results "one landmark step in a very long journey" toward creating DNA-matched transplant tissue. Mitalipov also said that based on monkey work, he believes human embryos made with the technique could not develop into cloned babies, and he has no interest in trying to do that. This reprogramming approach is technically simpler and doesn't involve embryos or require the donation of human eggs, and it was widely acclaimed when it was reported in 2007. Mitalipov and Tachibana are now conducting a study to compare iPS cells and SCNT cells derived from the same donor cell.
– Scientists have made a long-sought—and controversial—breakthrough: They created stem cells from cloned human embryos for the first time, reports AP. In theory, the development by researchers at Oregon Health & Science University means that doctors might someday be able to grow tissue from an ailing patient's own DNA, thus reducing the chance of rejection in a transplant. Commonly cited examples are growing brain tissue to help a patient with Parkinson's disease, or pancreatic tissue to help diabetics. It's "one landmark step in a very long journey," says an expert at Children's Hospital Boston who wasn't involved with the work. The Oregon scientists say they don't think the embryos used in their process could develop into babies, reports NBC News, but the procedure is nonetheless controversial because it requires that the embryos be destroyed. Nature notes that competing technology in the last decade has made the push toward embryonic stem cells less intensive, but adds that the new paper in Cell is sure to reignite the debate. The scientists used eggs from donors, and it took six years to replicate the success they had with monkey embryos. They chalked it up to a series of small revisions over the years instead of a single aha! moment.