It may be surprising to learn that humans and horses share many physiological similarities, particularly in terms of health and development. Jane Manfredi, associate professor of pathobiology and diagnostic investigation in Michigan State University’s College of Veterinary Medicine, is an expert when it comes to identifying these similarities. Manfredi answers questions on what we can learn from equine health research and how it can benefit humans.
Responses are excerpts from an article originally published in The Conversation.
Why look for connections between equine and human health?
There’s a principle in medicine called One Health, which says that animals, humans and the environment are inextricably connected — for one to be healthy, all must be healthy.
It also means that we can learn a lot about our own health by studying the health of animals, and vice versa, including the many parallels in endocrine disorders between humans and horses.
How are human and horse endocrine systems similar?
The endocrine system produces hormones that support many of the body’s basic functions, including growth and development, metabolism, sleep and more. Hormones also play a role in the health of the tendons and ligaments. Some endocrine disorders change how the body produces and releases hormones and can lead to osteoporosis, arthritis, ligament injury and other orthopedic diseases.
Humans are not the only species affected by this dynamic — horses are, too. In fact, approximately 20% of horses and over 34% of people in the U.S. are affected by endocrine disorders such as metabolic syndrome. These disorders are often accompanied by obesity.
Like people, obese horses with endocrine disorders often develop low-grade inflammation. Inflammation is a normal response to injuries and sickness. But chronic, low-grade inflammation can have long-term negative effects on the body. In people, childhood obesity, which is related to maternal obesity, is associated with a type of joint disease called osteochondrosis. Foals born from obese mares are also predisposed to this same type of joint disease.
Both horses and people with endocrine disorders like Type 2 diabetes can suffer multiple types of musculoskeletal disorders. For example, horses with pituitary pars intermedia dysfunction — similar to Cushing’s disease in people — suffer from tendon and ligament degeneration.
What are some treatments that benefit both species and support the need for further research?
Because of the similarities between people and horses, research on diagnostics and treatments for metabolic conditions could provide health benefits to both species.
For example, a class of drug called glucagon-like peptide-1 agonists, which includes brands like Trulicity (dulaglutide) and Ozempic (semaglutide), is commonly used to treat metabolic syndrome and Type 2 diabetes in people. This class of medication is also effective in treating these conditions in horses, similarly, slowing down how quickly food empties the stomach and reducing glucose release into the bloodstream.
Another class of drugs called sodium-glucose cotransporter protein-2 inhibitors, which includes such treatments as Jardiance (empagliflozin) and FARXIGA (dapagliflozin), are used to treat Type 2 diabetes in people and a similar condition in horses. These drugs alter the kidneys’ ability to absorb sugar from urine such that the body eliminates some of the glucose it would normally absorb. This greatly reduces blood insulin spikes, which can help prevent obesity, metabolic syndrome and cardiovascular disease in both horses and people.
What is precision medicine and why is it important?
Instead of the standard one-size-fits-all protocol, precision medicine uses information from a person’s genes, environment and medical history to create a customized treatment plan. For example, precision medicine is often applied in oncology when doctors gather genetic information about the patient’s cancer tumor to inform which treatments might work best for them.
In horses, precision medicine currently focuses on DNA-based diagnostic tests to inform exercise regimens, treatment and breeding decisions. Recent work with horses also suggests that measuring the heritability of certain metabolic traits could be used to screen for metabolic syndrome in the future.
Within precision medicine, doctors aim to get a full-picture view of an individual and their metabolic health. The more researchers learn from individual patients, including horses, the better equipped doctors will be to treat every patient.
