Taking a One Health Approach to Muscle Loss Research
Two Tufts scientists provide an example of how a One Health collaboration between animal and human health researchers can achieve better outcomes for people and pets.
Sarcopenia, the medical term for age-related decline in muscle mass and strength, is a syndrome commonly seen in humans and companion animals, such as dogs and cats. It is a common indicator of the aging process as well as diseases like cancer and heart disease.
That’s why veterinary nutritionist Lisa Freeman, A86, V91, N96, reached out to Roger Fielding, N93, associate center director of the Jean Mayer USDA Human Nutrition Research Center on Aging (HNRCA) at Tufts. Fielding is an expert on sarcopenia in humans, and Freeman wanted to see if the international conference he was helping to organize could include information on sarcopenia in animals.
The upshot is that the International Conference on Frailty and Sarcopenia Research, which kicks off April 20 in Boston, will include a satellite summit titled “Sarcopenia Across Species: A One Health Approach.” The goal: to get more scientists who work on human muscle wasting and frailty, as they affect healthy aging, talking with scientists who study similar issues in companion animal health .
“It’s just not as effective or efficient to study muscle wasting in parallel,” says Freeman, professor of clinical nutrition at the Cummings School of Veterinary Medicine, who holds a veterinary degree and a Ph.D. in Tufts Nutrition.
“We can each learn so much more from each other and by working together,” says Fielding, who is also a principal investigator on the HNRCA sarcopenia team and a professor of biochemical and molecular nutrition and medicine. “I thought that was a great idea.”
Why study aging in companion animals?
Relatively speaking, it is easier to study disease states and test potential treatments in laboratory rodent models. But rodents aren’t similar enough to humans to consistently be good predictors of positive outcomes in human clinical trials. “When we go from mice to humans, we frequently have translation failures, and what looked like a treatment that would succeed in preclinical studies often doesn’t work in humans,” Freeman says.
“In rodent models studied in the laboratory, all rodents are genetically identical,” adds Freeman. “They are brought up like that. By comparison, companion animals have greater genetic variability than laboratory animals, and they actually live in the same environments as their human companions. These two factors together make them potentially better to study.
Natural muscle wasting and weight loss are very common in pets as they age. Pet dogs and cats also commonly develop other human diseases that involve muscle and weight loss, including heart failure, cancer, and kidney disease.
Just as humans live longer, so do cats and dogs. As the population of older pets grows, it becomes easier to study natural diseases and conditions that, like sarcopenia, develop as part of aging.
In fact, one such study that will be discussed at the conference, called The Dog Aging Project, will follow tens of thousands of pet dogs for 10 years to identify biological and environmental factors that maximize healthy longevity. The goal is to use the information gathered to help dogs and humans increase their lifespan, or the period of life spent free of disease.
Increase the quality, not just the quantity, of life
Sarcopenia can cause decreased strength and balance and is a component of the so-called “frailty syndrome”, which can impact healthy aging in pets and older humans. because their body loses the ability to respond to stress, whether it is injury or illness.
Several classes of drugs under study target various pathways that may be involved in muscle loss as humans and pets age. These include steroidal and nonsteroidal anti-inflammatory drugs; drugs targeting ghrelin, a hormone that stimulates appetite and increases food and muscle intake; and drugs targeting myostatin, a protein that when overproduced in the body can inhibit muscle cell growth. The important roles that exercise and nutrition can play in slowing muscle loss are also reviewed.
“Much of the research and clinical efforts in the field of aging, both for humans and pets, are now focused on the study of health span rather than lifespan,” says Fielding. “People are not only interested in living longer, but in living disease and syndrome free for as long as they can. People are more concerned about their quality of life, about not losing their independence and having to rely on others for care.
“We are always looking for ways to improve our quality of life and that of our pets,” he adds.