Alzheimer’s in dogs: are we closer to finding an effective treatment?

It is a fact that older dogs naturally develop a dementia-like syndrome with biological, clinical and therapeutic similarities to Alzheimer’s disease (AD) in humans. Australian biomedical company Skin2Neuron has successfully tested a new kind of cell therapy in older dogs, that appears to reverse dementia-like symptoms.

Veterinary trial

The first phase of the veterinary trial, conducted with 6 companion dogs with Canine Cognitive Dysfunction (CCD) for a period of 3 months, concluded that cell therapy may have the potential for treating carefully chosen CCD sufferers based on neurosynaptic restoration in the hippocampus.

“We expanded the cells in the lab, and then a neurosurgeon microinjected the cells into the hippocampus. From there, the cells migrated to the right location and began to mature into adult neurons, eventually making connections within the relevant memory circuit,” Skin2Neuron co-founder Michael Valenzuela explains to PETS International. “As a result, we saw the dogs’ dementia reverse and their behavior get back to normal.”

Do dogs hold the key to treatment for humans?

However, this process requires sophisticated neurosurgical equipment that is usually only available for human patients, so a canine version of the treatment currently costs over $10,000 per animal. Nevertheless, Valenzuela, who is also an advisor to the World Health Organization (WHO) as part of the Clinical Consortium on Healthy Ageing, hopes that the treatment can eventually be successfully administered to both humans and dogs, thanks to the fact that the canine brain is so similar to the human brain.

A recent study led by the University of Washington in Seattle (US) recognized this similarity and stated that ‘dogs exhibiting CCD may offer researchers a valuable animal model in which to study characteristics of neurodegenerative diseases that are relevant to, but challenging to study in, human populations’. ‘Dogs with CCD could serve as candidates for AD-preventative and/ or therapeutic strategies,’ according to the University of Washington. This could represent a major breakthrough in view of the fact that Alzheimer’s disease is the sixth leading cause of death in humans in the US.

It is believed that CCD progresses at a faster rate in dogs as they have shorter lifespans. “There are certain diseases where in humans we have to wait 5 years, 10 years or 20 years to really see something which will happen in a year or 2 in a dog,” says Assistant Professor Jan Krumsiek from New York-based Weill Cornell Medicine.

Canine dementia risk doubling over age 10

“CCD is a huge issue for dogs and their owners because it destroys the human-animal bond, and is often a reason for euthanasia because the dogs become just too difficult to manage,” explains Michael Valenzuela. He points out that the prevalence of CCD is around 5% in dogs aged 10 years, doubling every 2 years thereafter.

This is echoed by a Scientific Reports study published in August, which was based on data from 2 surveys completed by the owners of 15,019 dogs as part of the Dog Ageing Project (DOP). The study was aimed at establishing baseline associations between selected characteristics collected through the Canine Social and Learned Behavior (CSLB) survey, consisting of 13 questions that assessed behaviors such as getting stuck behind objects, pacing, and failing to recognize familiar people. It found that while the prevalence of the condition was near zero in dogs below the age of 10, the likelihood of developing CCD increased by 52% with each year a dog aged. The results also showed that the odds of developing CCD were 6.5 times higher among dogs with lower activity levels over the past year.

Understanding the disease

While the current studies of dementia in dogs are focused on advancing human treatment, there are hopes that a better understanding of the cognitive disorder will also improve treatments for the canine population. In the meantime, drugs – including antidepressants –are also prescribed, and dog owners are often advised to change their pet’s diet as well as to increase their activity levels to manage the symptoms.

Nick Sutton, a dog health and science expert at The Kennel Club, backs up the idea that it is important to keep the dog fit and healthy in its senior years. “Walking the dog and taking it for exercise lowers its risk of dementia,” he comments.

One Health

Despite there being no known cure for canine dementia, the scientific community is trying to improve the understanding of this cognitive disease by working towards One Health: a joint initiative of several disciplines to bring about human, animal and plant health in sustainable ecosystems across the world using a chain approach.