CAHF research: 2020-21

Eight research teams at the Western College of Veterinary Medicine (WCVM) have received $117,429 in funding to conduct vital companion animal health research.

What do EphA proteins tell us about a common eye tumour?
Drs. Stephanie Osinchuck, Behzad Toozi, Lynne Sandmeyer and Leila Bedos, and Evelyn Harris, WCVM

Ocular melanoma, the most common type of eye tumour in dogs and cats, usually causes blindness. While current treatment involves removing the eye once blindness occurs, there’s a risk that the tumour will have already spread to other parts of the body.

Studies of human tumours have shown the overexpression of a group of proteins known as the EphA receptors. Since these receptors regulate cancer cell multiplication, survival and invasion, they are considered possible targets for new cancer treatments.

Using fresh and archived tissue samples from canine and feline tumours as well as matching normal samples, researchers will employ quantitative polymerase chain reaction (qPCR) and immunofluorescence staining to investigate the expression of EphA receptors. This information will inform how EphA receptors influence tumour development. The scientists will also use messenger (mRNA) sequencing to evaluate alterations in gene expression within the tumours compared to the normal tissue.

By studying the involvement of EPhA receptors in tumours, researchers strive to predict the invasiveness of the tumours and identify new targets for ocular melanoma therapy in dogs and cats.

How do nesfatin-1 levels differ in healthy dogs and cats compared obese or diabetic pets?
Drs. Suraj Unniappan, Elisabeth Snead and Melissa Meachem, WCVM

Obesity and diabetes are two major diseases affecting companion animal health. Research indicates that a hormone called nesfatin-1, which is present in dogs and cats, plays a role in human clinical conditions including diabetes and obesity.

This project will develop tests for measuring nesfatin-1 in the tissues and bodily fluids of cats and dogs. By comparing the levels of nesfatin-1 in healthy animals to those affected by diabetes or obesity, researchers can develop a better understanding of the hormone’s role.

The researchers will begin by developing antibodies specific for nesfatin-1 in dogs and cats and will then use them to create a measurement tool called a radioimmunoassay (RIA). After validating this RIA using canine and feline serum, plasma and tissue samples, the research team will use the test to measure nesfatin-1 levels in the serum and plasma of healthy dogs and cats compared to those animals deemed obese or diabetic.

Developing these nesfatin-1 antibodies and nesfatin-1 RIAs will help to support veterinary diagnostics, treatments and research involving diabetes and obesity in dogs and cats.

Can we treat canine osteosarcoma by targeting EphA2 proteins?
Drs. Behzad Toosi, Valerie MacDonald, Jerome Gagnon and Jessica Sharpe, WCVM

Osteosarcoma is a common canine bone cancer that is routinely treated with amputation combined with chemotherapy. Unfortunately, most animals survive less than a year following treatment.

While immunotherapy treatments for cancer have proven effective, their development is based on targeting the specific proteins that promote cancerous growth. Researchers have identified EphA2 as one such protein group and will further investigate its role in promoting osteosarcoma cell growth.

Using up to 10 osteosarcoma tumour samples and normal bone specimens from the WCVM Veterinary Medical Centre, the researchers will compare EphA2 expression in tumour versus normal cells. They will then “silence” EphA2 expression in specific osteosarcoma samples and compare to non-silenced samples to determine the impact of EphA2 on osteosarcoma cells — their growth, viability and migration. Researchers will also use mice to compare the growth patterns and metastases of osteosarcoma cells with silenced versus unsilenced EphA2 expression.

This study will significantly contribute to an understanding of the molecular biology of osteosarcoma, a key requirement for developing new treatments. Since human and canine osteosarcomas are very similar, these findings will also benefit oncology treatments for people.

How do different anesthetic drugs affect peri-anesthetic cardiac arrhythmias in cats?
Drs. Shannon Beazley and Tanya Duke, WCVM

Abnormal heart rhythms can occur in dogs and cats following general anesthesia, but so far, scientists have only investigated the prevalence of post-operative cardiac arrhythmias in dogs.

Dexmedetomidine and acepromazine are two anesthetic agents that veterinarians frequently use to premedicate healthy cats undergoing elective surgical procedures. However, no one has studied the drugs’ impact on cats’ cardiac activity in the intra- and post-operative period.

During this study, researchers will investigate 50 client-owned cats brought to the WCVM Veterinary Medical Centre for spay procedures (ovariohysterectomy/ovariectomy). Team members will fit each animal with a lead Holter monitor before sedation with acepromazine or dexmedetomidine mixed with hydromorphone. All cats will receive similar dosages of anesthetic drugs (alfaxalone and isoflurane) mixed with hydromorphone. After surgery, the cats will receive similar pain control drugs. At 20 to 24 hours post-surgery, researchers will remove the Holter monitors and analyze their recordings.

This study will quantify and characterize cardiac arrhythmias during the post-anesthetic period following the use of two common drug protocols, and it will contribute to current knowledge regarding cardiac conduction abnormalities during and following anesthesia and surgery in cats.

Should we use Yunnan Baiyao as a hemostatic drug for dogs?
Drs. Anthony Carr, Kevin Cosford and Siu To Koo, WCVM

Yunnan Baiyao (YB) is a traditional Chinese medicine that’s often used to treat bleeding in veterinary patients — but there’s no information available to support its efficacy as a treatment. Previous studies indicate that administering YB is safe in dogs. However, its impact on blood clotting in healthy animals is still undetermined.

This study will evaluate the efficacy of YB by using a platelet aggregation test to measure its impact on a group of healthy dogs with a mild bleeding tendency induced by acetylsalicylic acid (Aspirin).

Using a group of staff-owned dogs, researchers will begin by establishing the animals’ baseline platelet values using aggregometry (measuring how well platelets clump together to form blood clots). After giving them a fixed dose of Aspirin for seven days, the researchers will then retest the dogs to determine their platelet response. Those animals with decreased platelet function will enter phase two for an additional seven days during which they will receive Aspirin plus an oral dose of YB. On day 14, their blood platelet function will be measured again.

If results indicate that oral administration of YB improves the animals’ platelet function, researchers will recommend that YB be used in clinical patients with bleeding disorders.

Is PET-CT effective for staging mast cell tumours in dogs?
Drs. Jerome Gagnon, Valerie MacDonald-Dickinson, Ryan Dickinson, Monique Mayer and Alison Williams, WCVM

While mast cell tumours (MCT) are the most common canine skin tumours, their impact on life expectancy varies greatly. Clinical staging of patients requires tests to determine evidence of metastases (spreading) to other sites — most significantly, the local draining lymph nodes.

The positron emission tomography-computed tomography (PET-CT) scan has proven valuable for detecting the changes in human cell metabolism that indicate tumour cells — particularly the increased uptake of a radiopharmaceutical drug such as F18 FDG, which is evidence of increased glucose metabolism.

The researchers will use PET-CT imaging to detect the presence of potential metastases in 20 client-owned dogs with MC tumours. After surgical removal of the primary mass and the local draining lymph node, histologic grading and lymph node analysis will enable researchers to determine whether the PET-CT scan results accurately predicted tumour metastases. They will also compare the histopathologic grade of the primary tumour to the rate of F18 FDG uptake observed during the scan.

This study should present evidence that PET-CT imaging is valuable for staging MC tumours, providing prognostic information and directing treatment of veterinary patients.

Can a preservative help to extend neutrophil function in blood samples?
Drs. Ryan Dickinson, Nicole Fernandez and Khawaja Ashfaque Ahmed, WCVM

Neutrophils are a type of white blood cell that is critical to the body’s immune defense mechanism. Laboratories commonly use flow cytometry to evaluate neutrophil function; low neutrophil numbers indicate increased susceptibility to infection — a particular concern for animals undergoing chemotherapy treatments.

Since neutrophil viability deteriorates over time, patient blood samples must be assessed within 24 hours after collection. That limitation causes issues when blood samples are required of patients living far away.

In this study, researchers will investigate the value of Q-VD-OOPh as a preservative. They will compare neutrophil function in standard blood samples to those containing a specific concentration of Q-VD-OOPh within six hours after collection and again at 24, 48, 72 and 96 hours. Using the same procedure, the second study component will evaluate and compare refrigerated blood samples, and the third will evaluate and compare samples containing various concentrations of Q-VD-OOPh.

Outcomes demonstrating that Q-VD-OOPh preserves neutrophil function over longer time periods will significantly increase opportunities for follow-up evaluation of blood samples, particularly for chemotherapy patients that don’t live close by.

Do specific genetic factors contribute to canine dilated cardiomyopathy?
Drs. Elemir Simko, Oksana Moshynska and Jennifer Loewen, WCVM

Clinicians are concerned about unusually high numbers of canine dilated cardiomyopathy (DCM) cases, particularly since dogs remain asymptomatic until the advanced stage when the heart can no longer pump blood to the body, resulting in death.

Since genetic factors have been attributed to DCM in people and several other species, researchers hope to identify genetic markers that will enable early diagnosis and treatment for dogs with the disease.

Using DNA cheek swab samples from 40 purebred dogs with DCM as well as 20 healthy age- and breed-matched dogs, the researchers will determine each dog’s genetic status of clear, carrier or at risk for two specific genes: PDK4/DCM1 and TTN/DCM2. Team members will also genotype and analyze samples using 200,000 genetic markers in order to identify other candidate genetic markers for canine DCM. By comparing the genetic status of those clear versus carrier or at risk, the scientists can then determine any correlation between DCM and the DCM genetic markers.

Early identification of dogs at risk will provide valuable information for veterinarians, dog owners and breeders, and it will help to support early diagnosis and treatment of DCM.