Why Old Dogs Might Be Able to Teach Alzheimer’s Researchers New Tricks

When I was growing up, my grandmother struggled with dementia, and I saw firsthand how difficult that was for our family. That experience was one reason I became a neurotoxicologist who studies how misshapen proteins and inflammation in the brain can increase over time and cause dementia. While there are ways to treat the symptoms of dementia, researchers are still in search of a cure.

Alzheimer’s disease and other types of dementia are difficult to study, in part because diagnosing the disease early in people is challenging. These diseases typically begin developing two decades prior to most symptoms that would prompt someone to see a clinician. As a result, most researchers use mouse models to test potential therapies for Alzheimer’s.

However, the effects of drugs developed in mice rarely translate to people. In fact, 99% of drugs developed for Alzheimer’s that showed promise in the lab failed in human clinical trials. Brain aging is hard to study in mice, as they do not naturally have the buildup of misshapen proteins seen in dementia.

Researchers can genetically modify mice to mimic what happens in a human brain, but it is difficult to mimic every aspect of dementia in one mouse. So, scientists have set out to research other animals that naturally experience what happens in the brains of people with Alzheimer’s or dementia. One particular species showing promise as a model to study neurodegenerative disease is the aging dog.

In our newly published research in the journal npj Dementia, my colleagues and I show that the aging dog brain changes in similar ways to a human brain with dementia – highlighting the value of companion dogs as a natural model of neurodegeneration that could help researchers develop better diagnostics and treatments for this disease. Our work on aging dogs all began with a desire to develop better treatments for dementia. Was there a better way to study the toxic proteins that cause disease than using mice?

Around the same time, I had learned that dogs also get dementia and partnered with my colleague Stephanie McGrath, a veterinary neurologist who studies companion dogs with brain diseases. She was interested in canine cognitive dysfunction syndrome, a condition similar to dementia in people. Canine cognitive dysfunction affects more than a quarter of dogs over age 12.