- BioTime and its collaborators reported on March 16, 2010 in a scientific paper titled “Spontaneous Reversal of the Developmental Aging of Normal Human Cells Following Transcriptional Reprogramming” the reversal of human cellular aging. The paper is online at
- The Company reported that by selecting for cells with sufficient levels of the immortalizing protein telomerase, they were able to reset the clock of aging back to the embryonic state.
- Using the new technologies of reprogramming, BioTime scientists showed that time’s arrow of development, as well as aging, could be reversed.
- BioTime revealed why existing Induced Pluripotent Stem (iPS) cell lines being studied showed signs of premature aging, and a means to overcome that roadblock.
- This new capability does not require the use of human embryos or egg cells.
- BioTime’s reversal of developmental aging may be the seed for future technologies that will one day allow young cells of any kind to be produced that might be useful for aging patients in repairing the heart, the blood system, the brain, and the retina, as well as many others applications. In this way, we might increase the “healthspan,” that is, the years free from expensive and debilitating disease.
In 1997 when Dolly the sheep was cloned, it occurred to some scientists that the transfer of DNA from the aged cells of the body into an egg cell was capable of changing the state of the cell in what could be compared to a cellular time machine. Despite the rumors that Dolly the sheep was born old because she came from an aged breast cell (hence her being named after Dolly Parton), scientists soon demonstrated that the cloning process really could reverse both the process of specialization of the body cell to make embryonic cells again, and surprisingly, cloning could also reset the clock of aging in cells. So, just like the immortal perpetuation of the species, cloning would allow a baby animal cloned from an aged body cell to be born young, and theoretically, the process could be repeated forever. If this could be tapped in the cause of medicine, it might be possible, similarly, to make unlimited young replacement body cell types forever to repair cells and tissues worn out with age. Early efforts to clone human embryonic stem cells, a process called therapeutic cloning to distinguish it from human reproductive cloning (the cloning of a human being), led to cloned embryos that would only grow to a small number of cells. In addition to the difficulties in making human therapeutic cloning efficient, the difficulty of sourcing human egg cells and the intense ethical controversy over the use of cloning in medicine made progress in the field relatively difficult. The good news is that in the years that followed, scientists identified some of the molecules within the egg cell that accomplish the work of cloning. These discoveries allowed these molecules to be used in such a way that egg cells were not required and no embryos were cloned. In other words, a cell type, such as a skin cell, could be coaxed back to an embryonic state in an ethically noncontroversial manner. Because these cells do not come from an embryo, they are called “induced pluripotent stem (iPS) cells” instead of embryonic stem cells. This transformation of a body cell back to an embryonic state uses proteins that are master regulators of other genes called “transcription factors.” Therefore this process is called “transcriptional reprogramming” or “iPS” technology. These cells exhibit pluripotent capabilities, meaning they have the potential to mature into all of the cell types or tissues types — skin, blood, bone or retinal cells, for example.