Scientists Reversed Aging in Mice, but It's No Fountain of Youth

Legends about the fountain of youth describe a well full of water that miraculously makes people who drink it or bathe in it young again. The groundbreaking study showing that gene therapy can reverse the aging process in mice, published Thursday in Cell, is not quite the same thing. But it’s just as cool.

In the study, a team of scientists spearheaded by the Salk Institute’s Juan Carlos Izpisua Belmonte, Ph.D., showed that they could genetically engineer mice in a way that allowed the researchers to wind back the clock on key signs of aging, kind of like hitting “rewind” on Netflix. After administering their new gene therapy to the mice for six weeks, the animals appeared visibly younger, had straighter spines, healed more quickly and, on the whole, lived 30 percent longer than their untreated counterparts.

That’s not going to happen for us anytime soon.

That’s because the study began with mice that were genetically engineered, from the single-cell embryo stage, to benefit from this sort of treatment. Until we get to the point where we can (and are willing to) edit the genomes of our own embryos, it’s unlikely that the results from this study can be applied directly to human aging. But the findings do point scientists in the direction of a set of genes that appear to drive aging as time passes — and can be “rewound” to more youthful states.

But the fact that these genes exist — the scientists refer to them as OSKM, a handy acronym for Oct4, Sox2, Klf4, and c-Myc — calls into question the idea that aging is simply a result of our bodies literally existing for too long. It seems intuitive to think that we get old because our bodies just get beat up over time, but the findings suggest that aging might be programmed into our cells from birth. It follows, then, that the programming that tells a cell to kick into “aging” mode at a certain point in time can be reset. Put another way, the life of a cell doesn’t always have to move in the forward direction.

The researchers chose these genes because they’ve been implicated in the formation of induced pluripotent stem cells, which have the potential to become any sort of cell in the body. In a way, these cells are “young” — they have a future full of options ahead of them. In nature, stem cells like these are normally not found anywhere but in early stage embryos (as young as it gets), whose cells haven’t yet specialized. But recently, scientists have discovered that they can take a specialized, “old” cell — say, a skin cell or heart cell — and activate some genes that tell it to revert to a younger, less specialized version of itself. The genes that Izpisua Belmonte’s team focused on are those genes.

Age reversal isn't just the stuff of legends.

In their experiment, the researchers genetically engineered the mice so that the OSKM were sensitive to a chemical that forced them to turn back their clocks. When the grown mice, carrying these genes, were exposed to a special chemical through their drinking water, these genes would turn on and the cell’s timeline would begin to roll back. The mice they used also had a disease known as progeria, which is associated with accelerated aging, so the results of the treatment were especially pronounced.

While it’s unlikely humans are going to be genetically edited in the same way as these mice anytime soon, it is possible that scientists will figure out how to achieve the same results using drugs that can turn the OSKM genes on or off. Izpisua Belmonte told the Guardian that he thinks such clinical applications won’t be happening for another decade. “These chemicals could be administrated in creams or injections to rejuvenate skin, muscle or bones,” he said. “We think these chemical approaches might be in human clinical trials in the next ten years.”

Science rarely hands us solutions that are as thorough or instantaneous as those that we’ve imagined through magic, but that doesn’t make them any less impressive or influential. Izpisua Belmonte’s findings don’t just have the potential to help us slow down aging in the future — they also have the ability to change how we think about aging now. What humans have long assumed was written in our stars, it seems, can actually be erased.

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