Study considers human medicine for answers on common canine immune disease
Like many other 3-year-old dogs, Oakley is full of energy. After coming back to her home in Beckley, West Virginia, after a run one day, everything seemed normal — but suddenly, Oakley’s nose started dripping blood.
Oakley is a rambunctious, “accident-prone” Doberman pinscher pup who gets knicks and scratches all the time and has never had a problem before, so the sudden, unstoppable bleeding terrified her owners, MacKenzie Milam and her mother Jennifer Milam.
After driving to multiple clinics, Oakley and her owners landed at the Virginia-Maryland College of Veterinary Medicine’s Veterinary Teaching Hospital (VTH) in the early hours of the morning.
Oakley didn’t lose any of her pep and playfulness, but she kept bleeding. At the VTH, the internal medicine team determined that Oakley had a disorder called immune-mediated thrombocytopenia (ITP). With medication, Oakley’s bleeding subsided.
When MacKenzie and Jennifer learned that assistant professor of small animal internal medicine Ashley Wilkinson is conducting a study on ITP, they jumped at the chance to enroll her.
"If you can help someone, or another animal, by all means,” Jennifer Milam said.
Research into ITP has the potential to help many dogs, as canine ITP is a common disorder, and it’s one of the top causes of a low platelet count in dogs.
"We see ITP very frequently in the hospital — there are many happy cases, but there are unfortunately also sad ones, so there's a lot of work to be done there," said Wilkinson.
ITP is an autoimmune disorder where the immune system destroys platelets, blood cells that bind together to stop bleeding. Most dogs are diagnosed with ITP after a scary, unstoppable bleeding incident like in Oakley's case, but some dogs are diagnosed after routine bloodwork finds an unexplainably low platelet count.
This discrepancy piqued Wilkinson's interest.
"With ITP in dogs, there's a huge spectrum in terms of presentation — some will be very stable and won't even have bleeding tendencies, and some will be very critical in the ICU with multiple blood transfusions, and some won't make it. It seems that the platelet count doesn't dictate what they look like clinically — it seems that there's something we're missing that affects their clinical picture," said Wilkinson.
The answer may lie in human medicine. In humans, it's difficult to differentiate between ITP and immune thrombotic thrombocytopenic purpura (iTTP), a diagnosis that does not exist in dogs.
Humans with iTTP have a deficiency of an enzyme called ADAMTS13 that's responsible for breaking down proteins that help with blood clotting called von Willebrand factor. With von Willebrand factor unchecked, blood clots excessively, resulting in a low platelet count due to the platelets being used excessively in the blood clots. Paradoxically, people with iTTP experience problems with both blood clots and excessive bleeding.
Wilkinson's study looks at the levels of ADAMTS13 in dogs with ITP, exploring the possibility that some dogs diagnosed with ITP may in fact have a different disorder similar to iTTP in humans.
"We typically use animal models to help us understand human disease, but in this case, humans are helping us consider this as a disease in animals," explained Sierrah Travis, a small animal internal medicine resident who also works on the study.
If they find that some dogs with ITP have low ADAMST13, it could kick off more research that could yield new, more effective treatments for those dogs who struggle with low platelets and bleeding problems.
That means more happy endings like Oakley’s.
Thanks to treatment and routine blood tests to monitor her ITP, Oakley has bounced back. Her owners report that she's had incidents where she's had nicks and scratches, and her blood has clotted like normal.
"We’re so happy she’s doing well — these success stories really warm our hearts,” said Travis.
