Aug. 7, 2008
More disease-specific cell lines have been generated, again without using embryos, eggs, or cloning. Researchers at Harvard announced they had produced 20 new human cell lines using the iPS (induced pluripotent stem) cell technology. The technique directly reprograms a normal cell, such as a skin cell, using 3-4 genes added to the cell via viruses. The iPS cells behave like embryonic stem cells but do not use embryos, eggs, or cloning, avoiding any need to create, destroy, or harm any human embryos. Japanese scientist Shinya Yamanaka developed the technique first in mice, then used the identical technique for human cells, without use of human embryos or human embryonic stem cells for any of his research.
The Harvard researchers developed disease-specific stem cell lines from patients with ten different diseases, including Parkinson's disease, Huntington's disease, Type I (Juvenile) diabetes, Down's syndrome, and two types of muscular dystrophy. The Harvard team, led by George Daley, said the point is not yet to treat anyone, but to get as many researchers as possible experimenting with these cells in lab dishes to better understand the diseases. Their hope is that the cells will provide clues for how the diseases develop, and possibly be used to test for drug treatments. A similar disease-specific cell line for ALS (Lou Gehrig's disease) was announced recently by another Harvard lab. Doug Melton, co-director of Harvard's Stem Cell Institute, said it is important to simply understand the diseases. "We don't even know when a patient gets diabetes if each patient gets it the same way," Melton said. "There could be 50 different ways." Melton plans to generate 50 diabetes-specific iPS cell lines from different patients in the next year. The goal of the Harvard core lab facility is to create 50 to 200 new iPS cell lines each year, in addition to hundreds expected to be made in other Harvard labs and around the world by other investigators.
The creation of these new disease-specific stem cell lines would seem to ring the death-knell of cloning (somatic cell nuclear transfer, SCNT). Supposedly the ability to reprogram a normal cell into a stem cell was the ultimate goal, allowing scientists to make cells that were disease-specific and patient-specific, for laboratory study and potentially for treatment. The cloning technique creates an embryo that can be destroyed to harvest its stem cells for experiments, or that can be implanted in a womb for gestation and birth. But cloning has never worked well, and requires a tremendous number of eggs, risking the health of women (see Pining for Clones, Whining for Eggs.) Yet despite his new success with iPS cells (and previous failures with cloning), Daley says cloning technology is still superior. "The egg does it faster and better," he said. Well, maybe, if it actually worked, theoretically. In the same way that, theoretically, a Star Trek transporter might be better than an elevator. But only one will get me there now, reliably, repetitively. And maybe fantasy is superior to reality in some current biotechnology circles. But the evidence indicates that now the only real use for cloning technology is to birth clones.
The study is published in the August 8 issue of the journal Cell.