Two Tufts scientists are providing an example of how a collaboration between animal and human health researchers can achieve better outcomes for both people and pets.
Sarcopenia, the medical term for age-related decline in muscle mass and strength, is a syndrome seen frequently in both 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; it can lead to decreased strength and balance; and it is a component of so-called “frailty syndrome,” which can impact healthy aging in older pets and humans as their bodies lose the ability to respond to stress, whether it be injury or illness.
That's why veterinary nutritionist Lisa Freeman, D.V.M., Ph.D., DACVIM, approached Roger Fielding, associate center director of the Jean Mayer USDA Human Nutrition Research Center on Aging (HNRCA) at Tufts. Fielding is an expert in sarcopenia in humans, and Freeman wanted to collaborate on issues related to sarcopenia in both humans and animals.
Relatively speaking, it is easier to study disease states and test potential treatments in rodent models in a laboratory. But rodents are not similar enough to humans to always be good predictors of positive results in human clinical trials. Companion animals have more genetic variability than lab animals, Freeman noted. This, along with the fact that companion animals live in the same environments as humans, makes them potentially better to study than rodent models.
Several classes of drugs being studied target various pathways that may be involved in muscle loss as humans and pets age. These include: steroidal and non-steroidal anti-inflammatory drugs; drugs targeting ghrelin, a hormone that stimulates appetite and increases food intake and muscle; and drugs targeting myostatin, a protein that when overproduced in the body can inhibit muscle cell growth. The important roles exercise and nutrition can play in slowing muscle loss are also being examined.
One goal, the HNRCA’s Fielding said, is to find ways to extend the “health span” of both humans and companion animals. In comparison to lifespan, which focuses just on the number of years an individual or pet lives, the term health span focuses on the quality of life during those years. Collaborating on the study of health span in humans and animals, offered Fielding, can help both groups live disease-free and syndrome-free for as long as possible.