CAHF research: 2021-22

Eight research teams at the Western College of Veterinary Medicine (WCVM) have received $102,542 in funding to conduct vital companion animal health research. Read the following research summaries for more information about each study.

Can grain-free, legume-based diets cause heart failure in dogs?
Drs. Lynn Weber, Matheus Costa and Dylan Olver, and Elise Bokshowan, WCVM

In the past two decades, the addition of legumes to grain-free diets in dog food have become increasingly popular as they are seen as a healthy alternative. But in the past few years, there have been worries that diets containing no grain and instead containing legumes such as peas and lentils may cause dilated cardiomyopathy (DCM) in dogs. DCM is a disease of the heart muscle that can lead to congestive heart failure in dogs. It may also cause decreased cognitive function by a change in blood flow to the brain.

These concerns have left pet owners wondering where to turn when feeding their pets. Grain-free, legume-based diets, which were previously perceived as healthy, are now being investigated as potentially harmful to their pets. 

Researchers believe a deficiency of taurine (an amino acid) contributes to an increased risk of DCM. In this study, WCVM researchers are looking to study whether or not the oligosaccharide (dietary fibre) in legumes correlates to low taurine levels in dogs. Previous research has shown that dogs with DCM have improved heart function when they receive taurine supplements.

As there is currently no link between the two, the researchers in this study strive to verify this link and whether the dietary fiber in legume-based diets is detrimental to dogs’ intestinal and heart health as well as their brain function. This critical information will help to support or refute the unproven hypothesis that grain-free, legume-based diets are unhealthy.

How can cancer-destroying molecules target canine osteosarcomas more efficiently?
Drs. Behzad Toosi and Valerie MacDonald, and Evelyn Harris, WCVM; and Dr. Franco Vizeacoumar, Saskatchewan Cancer Agency

Osteosarcoma is an extremely common bone cancer seen in dogs and it accounts for a large majority –– nearly 80 per cent –– of all bone tumours in dogs. Current treatment for a canine osteosarcoma is quite aggressive and includes chemotherapy and amputation of the affected limb. However, even with the treatment, there is a chance the cancer may spread throughout the body. Even after aggressive treatment, dogs diagnosed with osteosarcoma usually only survive for a year after the procedure.

The WCVM researchers in this study aim to find a precise and effective treatment for canine osteosarcoma that has better outcomes. They will first identify molecules that will destroy cancer cells in order to improve the treatment for canine osteosarcomas. The group has already identified erythropoietin-producing hepatocellular receptor tyrosine kinases (Eph RTKs) as possible targets for bone cancer treatments. These Eph receptors have been studied in malignant human bone tumours and are often associated with increased tumour spread. These receptors have not yet been studied in dogs.

Through analysis of healthy canine bone cells as well as bone cells affected with an osteosarcoma, the research team will work to design a better treatment for bone cancer in dogs. 

Does yeast cause skin conditions in guinea pigs?
Drs. Allison Foster and Isabelle Desprez, WCVM

Guinea pigs are common pets and are often seen by veterinarians due to skin conditions. There are relatively few studies on guinea pigs in relation to skin conditions, so it’s often difficult to diagnose them correctly. 

Yeast is an organism often found on dogs and cats. Described as a commensal organism, yeast survives on the food provided in the internal or external environment of their host without establishing a close relationship. The organism can be found on healthy skin but can also cause dermatological problems such as allergic dermatitis and endocrinopathies. Due to the lack of information available on the normal state of a guinea pig’s skin, researchers still don’t know how yeast can benefit or damage its skin.

WCVM researchers aim to report on the status of yeast on the skin of guinea pigs with different skin conditions: healthy guinea pigs with no apparent skin condition, guinea pigs with a skin condition and guinea pigs with other conditions unrelated to skin. The team will also observe what types of yeast organisms are present on the skin of guinea pigs. This study’s findings will help to provide veterinarians with a baseline of information about skin conditions in guinea pigs.

How can we distinguish between two feline oral cancers?
Drs. Bruce Wobeser, Helene Philibert, Shelagh Copeland and Vasyl Shpyrka, WCVM

There are very few published studies targeting feline oral tumours. Squamous cell carcinoma (SCC) and peripheral ameloblastoma (PA) are two oral cancers found in cats. These two cancers are very different and have very different outcomes, but when it comes to diagnosing them, it’s very difficult to distinguish between the two. 

Cats diagnosed with SCC generally survive less than two months. To diagnose this type of cancer, veterinarians rely on histopathology –– the diagnosis and microscopic study of tissue diseases. What’s challenging is that PA presents similarly to SCC but has a much better prognosis; this type of ameloblastoma doesn’t spread and isn’t deadly. Veterinarians don’t have access to any other test beyond microscopic examination to differentiate the two cancers.

Based on past studies, scientists have identified two immunohistochemical (IHC) markers –– ameloblastin (AB) and amelogenin (AG) –– that could be used to potentially distinguish these oral cancers. WCVM researchers will conduct a larger study to determine if these IHC markers, which should be present in PAs and absent in SCCs, are effective in differentiating these two feline oral tumours when histopathology results are not enough. 

What’s the best way to administer pain medications to ferrets?
Drs. Barbara Ambros, Isabelle Desprez and Dennilyn Parker, WCVM; and Dr. Heather Knych, University of California Davis

Ferrets are common pets around the world. Researchers also use ferrets in the laboratory as animal models to study human diseases such as COVID-19. The appropriate use of pain medication (analgesic drugs) for ferrets when they undergo surgery or disease processes is of utmost importance to animal welfare. However, when it comes to managing pain in ferrets, researchers currently rely on methods largely based on those used in other species. 

Scientists have previously studied hydromorphone, a morphine-like medication, that’s commonly used to manage pain in dogs and cats. WCVM researchers will administer a single dose of hydromorphone to ferrets in two different ways to measure its effectiveness and pharmacokinetics –– the way the medication moves through the body. The study’s two groups of ferrets will have hydromorphone administered either intravenously (in a vein) or subcutaneously (under the skin). After the dose is given, researchers will collect blood samples so they can measure hydromorphone concentrations. The research team will also observe the ferrets for behavioural side effects, like sedation, after treatment.

This study will determine accurate dosages of pain medication in ferrets, which will help to improve overall pain management and the animals’ welfare.

How does hyperthyroidism affect blood clots in cats?
Drs. Kevin Cosford, Tony Carr, Elisabeth Snead and Daniel Moreno Reyes, WCVM

Hyperthyroidism, a condition common in both cats and people, occurs when the thyroid gland produces excess amounts of the hormone thyroxine. Humans with hyperthyroidism are twice as likely to develop a blood clotting disorder in their veins or pulmonary artery than others with a normally functioning thyroid. Cats with hyperthyroidism can also form blood clots, leading to complications including hindlimb paralysis and death.

Researchers aren’t well-versed in the relationship between hyperthyroidism and hemostasis (the state in which the body is balanced) disturbances in cats. In this study, WCVM researchers will use three methods to evaluate hemostasis in cats and to better understand the effects of hyperthyroidism: Chrono-Log platelet aggregometry, thromboelastometry (TEG) and rotational thromboelastometry (ROTEM) to better understand the effects of hyperthyroidism on hemostasis. 

The research team will use these three technologies to measure primary and secondary hemostasis in cats with hyperthyroidism and with euthyroidism (in which the thyroid functions normally). Their objective is to discover if and how hyperthyroidism is directly linked to the development of blood clots in cats. By working to understand what tends to lead toward blood clotting more quickly, the researchers’ findings may prevent potentially devastating cardiovascular complications in cats.

Can a surgery to prevent lameness in large dogs be equally as effective in small dogs?
Drs. Koji Aoki and Ariel Schlag, WCVM; and Dr. Kei Hayashi, Cornell University College of Veterinary Medicine

Cranial cruciate ligament (CrCL) disease is the most common cause of lameness in a dog’s hind legs. As the knee bone and shinbones slide past one another, CrCL can cause knee instability and arthritis. 

Before conducting a surgical procedure called the tibial plateau leveling osteotomy (TPLO), veterinary surgeons use X-rays to determine where to cut the dog’s upper shinbone and rotate it to stabilize the knee. This surgery is typically done in larger dogs weighing over 15 kilograms (about 33 pounds). Large breed dogs have a more gradual slope between their shins and thighbones than small breed dogs. The TPLO procedure is less commonly used in smaller dogs (under 15 kg) because of the steeper slope between their shins and thighbones.

A recent study showed improved weight-bearing in small breed dogs that underwent TPLO surgery –– results that will likely lead to more veterinary surgeons using TPLO surgery in small dogs. In this study, WCVM researchers will examine the accuracy of the operation as well as any complications that may arise in small dogs. They will also investigate the possible improvements that could be made and compare these results to those of large breed dogs. This study will help to evaluate the surgery’s accuracy, which could ultimately help to improve treatment for small dogs diagnosed with CrCL.

Can a fluid-to-tissue conversion method diagnose conditions in cats and dogs more effectively?
Drs. Melissa Meachem and Bruce Wobeser, WCVM

Assessing the bodily fluids of cats and dogs under a microscope doesn’t always result in definitive diagnoses, especially in animals with underlying cancers. The cell tube block (CTB) is a new method that may improve diagnoses by transforming fluid into tissue through sedimentation and formalin fixation of cells. 

CTB is a quick and inexpensive procedure. The benefits of this method include the routine use of immunological stains, the preservation of three-dimensional tissue architecture and the ability to store fluid samples for future diagnoses and research. Past studies have found that cell blocks are better diagnostic indicators than cytology alone, especially in possible cancer cases.

WCVM researchers will assess 50 fluid samples from dogs and cats using the CTB method and study the appropriate immunological stains. The researchers expect CTB to improve diagnosis rates and be useful in identifying populations of lymphocytes –– a type of white blood cell. The CTB method may also be beneficial in diagnosing feline infectious peritonitis (FIP) –– a viral infection caused by strains of the feline coronavirus.

Findings from this study may result in the more routine use of CTB in diagnostic laboratories, which will improve patient outcome. If successful, the study’s results may also help to avoid the need for further –– and possibly invasive –– tissue collection.