CAHF Research Grants: 2017-2018

Research conducted by Dr. Marina Leis will identify factors that put cataract surgery patients at risk for developing glaucoma. Photo by Christina Weese.

Six research teams at the Western College of Veterinary Medicine (WCVM) have received more than $68,500 in funding to conduct vital companion animal health research in the next 12 months.

Four of the research projects received funding from the WCVM Companion Animal Health Fund, while two other WCVM-administered funds — the Anka Best Friend Fund and the Olga and Constance Kaye Canine Research Trust Fund — provided financial support for two more studies.

All of the research work will be conducted by WCVM scientists and their collaborators over the next 12 months. Read the following research summaries for more details about each study.

How can we improve post-operative care and pain management in guinea pigs?
Drs. Barbara Ambros and Miranda Sadar, WCVM

As a prey species, guinea pigs often freeze to avoid predators’ attention. But this trait makes it difficult for researchers to assess how much pain guinea pigs feel and whether pain-relieving drugs are effective. Guinea pigs might behave one way under observation, and then another way when they think they’re alone.

In this study, WCVM researcher Dr. Barbara Ambros will validate the use of thermal threshold (TT) testing to assess how well certain drugs relieve pain in guinea pigs. In TT testing, researchers observe animals for their responses to stimuli so they learn more about the animals’ pain thresholds. The WCVM research team will use an adapted version of a TT testing device that was previously used with cats.

Researchers will explore whether the presence of an observer influences TT testing results. They will also look at the opioid drug buprenorphine to see how well it manages pain in guinea pigs. Their findings will help researchers learn more about pain management in guinea pigs — an area in which there is very little information available.

Study results will help veterinarians and researchers understand and improve post-operative care and pain management in guinea pigs — a species that has become a popular pet around the world and a common subject in biomedical research studies.

What’s the best X-ray technique for detecting free gas in a dog’s abdomen?

Drs. Kathleen Linn, Jiaying Ng, Cindy Shmon, Gregory Starrak, Sally Sukut and Justin Whitty, WCVM

The abnormal presence of gas in a dog’s abdomen can be a potential sign of a rupture in the stomach or intestinal tract — a life-threatening condition that requires emergency surgery to correct. But it can be difficult to detect the gas: overlapping abdominal structures can make it hard to tell if gas bubbles are within or outside the gut, plus the intestine normally contains some gas.

Veterinarians use several X-ray and ultrasound techniques as well as computed tomography (CT) to try and get a look at what’s going on inside of a dog when they show signs of a stomach or intestinal tract rupture. But so far, no one has identified the best technique for detecting small amounts of free gas.

In this study, Dr. Kathleen Linn and a team of WCVM researchers will attempt to define the best X-ray technique for diagnosing abdominal and intestinal ruptures. Once this study is complete, they will use the identified technique in a second prospective study to determine how long veterinarians can expect free gas to persist after abdominal surgery.

These findings will also help clinicians determine whether post-operative gas is a normal result of the abdominal surgery, or if it indicates complications such as a surgical incision rupture.

What’s the metabolic response to dexmedetomidine in healthy cats?

Drs. Kevin Cosford, Elisabeth Snead, Tanya Duke and Juliette Bouillon, WCVM

Veterinarians commonly use a drug called dexmedetomidine to keep cats and dogs comfortable during simple procedures such as ultrasound examinations and suturing of small wounds. The drug has become popular because it’s a reliable sedative and the effects can be reversed. However, it may also increase blood glucose concentrations by decreasing the release of insulin from the pancreas.

Although veterinarians routinely sedate diabetic cats with dexmedetomidine, no studies have been done to assess the drug’s endocrine effects in this group of pets. As a first step, WCVM researcher Dr. Kevin Cosford will explore the effects of the sedative on the endocrine systems of eight healthy cats. Over a period of two weeks, the cats will be given doses of dexmedetomidine or saline. The team will take blood samples before and after the animals are sedated to see if the blood sugar and the hormones that control the blood sugar are affected.

Once the WCVM research team understands how dexmedetomidine affects glucose regulation in healthy cats, that information can help veterinarians determine the drug’s impact on pre-diabetic, obese and diabetic cats — and whether it’s a safe option for these patients.

Are fecal bacteria in dogs resistant to chemotherapeutic drugs?

Drs. Joe Rubin, Jerome Gagnon, Olivier Campbell, Valerie MacDonald Dickinson, WCVM

The rise of antimicrobial resistance (AMR) is considered one of the greatest threats to modern medicine, and it’s changing the way that veterinarians and human doctors think about treating their patients. Every time we use an antibiotic, we encourage the bacteria to adapt and develop resistance — but other non-antibiotic drugs can also affect bacteria and may similarly select for resistance. In this study, WCVM scientist Dr. Joe Rubin and his research team will seek to understand how the antimicrobial susceptibility of fecal bacteria (Staphylococcus pseudintermedius and Escherichia coli, specifically) respond to chemotherapeutic drugs used to treat dogs with lymphoma.

The drugs used against lymphoma have antibiotic properties, but so far, no one has investigated whether these drugs can lead to the development of AMR in canine patients. Since chemotherapy compromises patients’ immune systems, the treatments could make cancer patients more vulnerable to infection from their own bacteria.

Rubin and his team suggest that chemotherapy may select for antimicrobial-resistant populations of E. coli and S. pseudintermedius by killing off susceptible bacteria.

During this study, Rubin’s team will study fecal antimicrobial resistance in dogs diagnosed with lymphoma before and during chemotherapy. Their findings will provide a deeper understanding of how antimicrobial resistance develops and could potentially change how veterinarians select antibiotics for dogs undergoing chemotherapy. Since no similar study has been performed with human patients, the study’s results may also have an impact on human medicine.

Can we trust CT images as the sole predictor of a gross tumour’s volume?

Drs. Monique Mayer, Sally Sukut, Cheryl Waldner and Jerome Gagnon, WCVM; Dr. Hiroto Yoshikawa, North Carolina State University; Dr. Keijiro Shiomitsu, University of Florida; and Dr. Elissa Randall, Colorado State University

Intensity modulated radiation therapy (IMRT) is a technique for treating tumours that uses precise radiation beams. In IMRT treatment, healthy organs surrounding the tumour are at less of a risk for tissue damage, and the tumour itself receives a higher concentration of radiation. Because the beam is so precise, performing this treatment without a detailed picture of the gross tumour could mean that some pieces are missed in treatment. Untargeted and left alone, the tumour regrows and the radiation therapy fails.

The best tumour imaging is accomplished with a combination of computed tomography (CT) and magnetic resonance imaging (MRI). Because access to MRI units is limited, some veterinary radiation facilities offer IMRT treatments with planning based only on CT images.

In this study, a research team led by WCVM radiation oncologist Dr. Monique Mayer will examine the potential consequences of using only CT imaging to prescribe IMRT treatment. MR images have better neuroanatomical detail than CT images. Mayer and her team hypothesize that using only CT images will mean an incorrect reading of the tumour’s size and shape, which means that in IMRT treatment some pieces of the tumour go untreated.

This research project is supported by the Anika Best Friend Fund

How can we prevent post-operative hypertension and glaucoma in dogs?

Drs. Marina Leis, Bianca Bauer, Lynne Sandmeyer, Bruce Grahn, WCVM 

Cataracts are the leading cause of blindness in dogs, but the surgical procedure for the disease has a high success rate. Unfortunately, the post-surgery outcomes aren’t as positive: 50 per cent of dogs can develop post-operative ocular hypertension (POH) and over time, about 15 per cent of dogs will develop glaucoma due to changes in the eye’s drainage structure. Glaucoma is a high-pressure ocular condition that can cause blindness and loss of the eye.

The filtration angle in a dog’s eye plays a key role in draining fluid away. With the use of ultrasound biomicroscopy (UBM), researchers can examine the filtration angle of a dogs’ eye structure before and after cataract surgery to better understand what puts some patients at risk for developing POH and glaucoma.

Dr. Marina Leis and a team of researchers will follow the cases of dogs undergoing cataract surgery at the WCVM with the goal of monitoring 100 dogs over the course of three years. The study’s primary objective is to identify factors that put cataract surgery patients at risk for developing glaucoma. The second objective is to report the filtration angle measurements of a dog’s eye structure in a controlled population of healthy dogs.

This research project is supported by the Olga and Constance Kaye Canine Research Trust Fund