While aging is not widely considered a disease, there are countless conditions that occur with increasing frequency as we age, such as heart or neurodegenerative disease. A new wave of therapeutics aims to prevent a whole host of age-related diseases by slowing the aging process itself. Decades of research have shed light on the genetics of aging and have pointed us to genes that may promote longer lifespans when activated, and developments in gene therapy are making it possible to activate these genes with a single injection.
A recent study from the Church lab at Harvard Medical School shows that over-expressing a combination of key genes can lower the risk for several age-related diseases in mice. The researchers injected mice with viruses modified to carry three genes implicated in aging, either individually or in combination and waited about 30 days for the treatment to take effect. Importantly, although these viruses insert DNA into the mouse cells, they do not edit the genome and this treatment is not passed on to the next generation. The virus mostly infects the liver, where these proteins will be made and transported throughout the body. Specifically, the researchers looked at symptoms of obesity and diabetes in mice fed a high fat diet, as well as kidney disease and heart function. Overall, they found that one or several of the genes they tested had significant effects in reducing symptoms for each of these age-related diseases. Indeed, hearts and kidneys from treated mice looked much more like the organs from younger mice than did the hearts and kidneys from untreated mice.
Therapies like this may one day be used in humans to help delay or prevent age-related diseases, but right now they’re being used to help prevent heart disease in dogs. Rejuvenate Bio, operated by several of the authors of this study, is currently running trials to treat mitral valve disease (MVD) in Cavalier King Charles Spaniels, a breed of dog naturally predisposed to the condition. The company does not say exactly what gene they use for this therapy, but it is likely the canine version of one of the genes from the mouse study.
Importantly, although the genes were selected for their effect on longevity, the researchers did not specifically test lifespan. Instead, they showed that by targeting the aging process they could mitigate the effects of multiple age-associated diseases at once. As this treatment is still in the early phases, many questions remain. For example, what will become the leading cause of death if not age-related diseases, and will this treatment increase healthspan, i.e. the amount of time lived before being afflicted with symptoms of old age? Only time will tell.
Managing correspondent: Julian Segert
Press article: A New Approach to Gene Therapy—Now In Dogs, Maybe Later In Humans Wall Street Journal
Original article: A single combination gene therapy treats multiple age-related diseases PNAS
Photo credit: Wikimedia Commons