Mice Genome Reprogrammed to Rejuvenate Organs and Extend Life
(p. A22) At the Salk Institute in La Jolla, Calif., scientists are trying to get time to run backward.
Biological time, that is. In the first attempt to reverse aging by reprogramming the genome, they have rejuvenated the organs of mice and lengthened their life spans by 30 percent. The technique, which requires genetic engineering, cannot be applied directly to people, but the achievement points toward better understanding of human aging and the possibility of rejuvenating human tissues by other means.
The Salk team's discovery, reported in the Thursday issue of the journal Cell, is "novel and exciting," said Jan Vijg, an expert on aging at the Albert Einstein College of Medicine in New York.
Leonard Guarente, who studies the biology of aging at M.I.T., said, "This is huge," citing the novelty of the finding and the opportunity it creates to slow down, if not reverse, aging. "It's a pretty remarkable finding, and if it holds up it could be quite important in the history of aging research," Dr. Guarente said.
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Ten years ago, the Japanese biologist Shinya Yamanaka amazed researchers by identifying four critical genes that reset the clock of the fertilized egg. The four genes are so powerful that they will reprogram even the genome of skin or intestinal cells back to the embryonic state.
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Dr. Izpisua Belmonte believes these beneficial effects have been obtained by resetting the clock of the aging process. The clock is created by the epigenome, the system of proteins that clads the cell's DNA and controls which genes are active and which are suppressed.
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Dr. Izpisua Belmonte sees the epigenome as being like a manuscript that is continually edited. "At the end of life there are many marks and it is difficult for the cell to read them," he said.
What the Yamanaka genes are doing in his mice, he believes, is eliminating the extra marks, thus reverting the cell to a more youthful state.
The Salk biologists "do indeed provide what I believe to be the first evidence that partial reprogramming of the genome ameliorated symptoms of tissue degeneration and improved regenerative capacity," Dr. Vijg said.
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(Note: the online version of the story has the date DEC. 15, 2016, and has the title "Scientists Say the Clock of Aging May Be Reversible.")