Scientists at the Salk Institute in La Jolla, California, have used gene therapy to reverse aspects of the aging process in mice. Though the researchers caution that a clinical application for humans is at best decades away, the research does open the door to such a treatment, and supports recent research suggesting that aging is driven by an internal genetic clock instead of simple wear and tear. After six weeks of treatment, the mice appeared younger, had straighter spines, improved cardiovascular health, healed faster, and ultimately had a 30 percent longer lifespan.
According to Juan Carlos Izpisua Belmonte, who led the research, “Our study shows that aging may not have to proceed in one single direction. With careful modulation, aging might be reversed.”
The research suggests a future in which doctors are able to treat the aging process itself, instead of just treating associated ailments and disease. The scientists are not claiming such treatments would be able to eliminate aging entirely, but that they may be able to slow aging and extend lifespan.
“We believe that this approach will not lead to immortality. There are probably still limits that we will face in terms of complete reversal of aging. Our focus is not only extension of lifespan but most importantly health-span,” said Izpisua Belmonte.
The technique used induced pluripotent stem (ips) cells to turn back the clock of aging on adult cells, such as skin cells. The cells are turned into powerful stem cells, not unlike the ones found in embryos, able be coaxed into becoming any cell type in the body. The new study uses these cells reverse aging cells without taking away their specialized function.
The mice used in the research were genetically engineered so the four genes used to turn skin cells into ips cells could be switched on when they were exposed to a chemical in their drinking water. The mice used in the experiment had progeria, a genetic disorder associated with accelerated aging, as well as damage to DNA and shortened lifespan. Six weeks of treatment improved skin and muscle tone and extended lifespan, and when the same genes were targeted in cells, DNA damage was mitigated, and mitochondrial function was improved.
“This is the first time that someone has shown that reprogramming in an animal can provide a beneficial effect in terms of health and extend their lifespan,” according to Izpisua Belmonte.
One concern was that cells would be fully turned into stem cells, which can spread uncontrollably through the body, leading to increased risk of cancer. Ultimately, the experiment did not increase cancer risk in the mice, but the risk means that such treatments would be first used for those with genetic conditions such as progeria, where the risk would be medically justified.
While the same treatment could not be used in humans since embryos would need to be genetically engineered, the researchers believe the same genes could be targeted with the use of drugs.
Izpisua Belmonte said, “These chemicals could be administrated in creams or injections to rejuvenate skin, muscle or bones. We think these chemical approaches might be in human clinical trials in the next ten years.”