Your dog may be on anti-aging medication before you are

It is likely that anti-aging drugs will be developed for dogs before they are developed for humans. Our best friends, dogs, are becoming increasingly popular as animal models of human aging, and there are currently multiple clinical trials testing potential anti-aging compounds in dogs. Dogs also represent a potentially huge market.

While this science could benefit both species, the premature claims are already raising questions about credibility.

Recently, Harvard biologist David Sinclair began selling a supplement that extends the lifespan of dogs. He touts unpublished clinical trial data that others in the field found wholly unconvincing. In March, Sinclair, who did not respond to requests for an interview, changed the wording of a press release that originally promised that the chewy treats would “reverse aging.” It now says they reverse the effects of age-related decline.

Sinclair’s studies used subjective owner assessments of changes in cognitive function in older pets, but other scientists have said trials haven’t shown enough consistent benefits to support even this modest claim. (Sinclair rose to fame in the 1990s with several highly publicized papers linking aging to proteins called sirtuins, an idea that led to the now widely debated belief that red wine has anti-aging properties.)

Although the FDA has the authority to regulate veterinary drugs, it does not approve supplements for pets or humans, which can be sold without being tested for safety or effectiveness.

Whether or not anti-aging supplements for dogs work, there’s likely to be a demand for them, says Arthur Kaplan, a professor of ethics at New York University. Until now, desperate dog owners have had their dead or dying dogs cloned, hoping that the clones will be a reincarnation of their dead pets.

Some aging researchers worry that the sight of a high-ranking professor peddling a longevity supplement for dogs will further tarnish the reputation of a field already tarnished by self-proclaimed experts promoting fad diets and unproven anti-aging treatments for humans.

There is much to be gained from a better scientific understanding of aging: Age is a risk factor for all the leading killer diseases, including heart disease, cancer, and even severe COVID-19. And in the United States, the number of people over 70 will increase dramatically over the next few years, dramatically increasing the number of people suffering from dementia and other age-related problems.

But scientists still don’t agree on what causes ageing or how best to slow it down. Wasting eventually affects all living things, but even among closely related species, some live many times longer than others. Some researchers believe that the rate at which animals age is controlled by specific genes.

Other experts blame it on the shortening of the caps at the ends of chromosomes, called telomeres. Others blame it on the deterioration of the packaging that holds our DNA together, or so-called epigenetic markers that activate or repress certain genes. Others blame damage from chronic inflammation. Still others blame it on the accumulation of cellular waste.

Some of the mechanisms of aging can be altered by drugs, extending lifespan in nematodes, fruit flies and mice. Which drugs should be tried in humans? Clinical trials to test effects on human lifespan can take decades, long enough for subjects to live the rest of their lives.

One way to identify more promising candidates is to see which treatments also work in dogs, which have longer life spans than mice and are good models of human aging, but their life spans are short enough that treatments can be tested within a few years.

Matt Kaeberlein, CEO of OptiSpan and an associate professor at the University of Washington, has been one of Sinclair’s most vocal critics of dog lifespan claims. He’s also in the race as co-director of the Dog Aging Project, which is collecting data from thousands of dogs and conducting clinical trials in dogs with a drug called rapamycin, which is currently approved for use in people who have received organ transplants. While high doses cause nasty side effects, such as mouth ulcers, Kaeberlein acknowledges, it can extend the lifespan of mice, and lower doses may have a similar effect in dogs and humans.

Biohacker groups are already taking rapamycin off-label in hopes of extending life, Kaplan says, and he’s trying to get data from them that might provide useful information, even if it’s messy. (Kaplan, the New York University ethicist, thinks it would be unethical for doctors to prescribe the drug off-label in hopes of extending life.)

Kaeberlein said biological data collected from thousands of dogs may explain why larger dogs don’t live as long as smaller ones: “If you compare the life expectancy of a Great Dane to that of a Chihuahua, the difference is at least two-fold,” he said.

But his project may have fallen victim to a field-wide credibility problem: The project was funded by the National Institutes of Health, but he and his colleagues recently learned that the five-year grant, which began in 2018 and was extended for one year, likely won’t be renewed. He’s now working on securing private funding.

Charles Brenner, a biochemist at the City of Hope National Medical Center in Los Angeles, has also been a vocal critic of Sinclair’s claims about dogs and humans. (Like most researchers at the forefront of aging research, Brenner has ties to the supplement industry as chief scientific adviser to a bioscience company called Chromadex.)

Brenner is also skeptical of those who claim that various treatments or drugs can reverse a person’s “biological age,” as calculated by telomeres, epigenetic markers or other indicators in the blood, none of which measure aging as well as walking speed, he says.

When I asked him about the dog study with rapamycin, he said the trial is “worth a try” because it measures actual lifespan, not a surrogate. But he’s not betting on this particular drug. He’s more optimistic about a study done by a company called Royal, which was featured in Bloomberg Businessweek in 2021.

Brenner said Royal has been secretive about the drug so far, but believes it blocks the production and action of growth hormone, which he says is linked to faster aging in larger dogs than smaller ones.

There’s potential in studying how and why animals age — not just dogs, but also clams that can live up to 500 years, rockfish that can reach 200 years, and whales that can live up to 80 years. If scientists understand the mechanisms of aging, they may be better able to find ways to help humans and our furry friends live longer, healthier lives.

But first, it needs to be taken seriously by investors and the public.

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