CAHF Research Grants: 2015-16
This year, the WCVM Companion Animal Health Fund provided financial support for eight pet health research projects at the regional veterinary college. Read the following research summaries for more details about each study.
Could a method used to treat liver disease in humans be applied to cats?
Drs. Ahmad Al-Dissi and Jolanda Verhoef, WCVM
Inflammatory liver disease is the second most common liver disease in cats. The exact cause of the disease is rarely identified, and because deterioration of liver function can’t be controlled, it results in poor patient outcomes.
In human medicine, physicians are taking a new approach to treating chronic liver diseases in people: they’re using a protein called metallothionein (MT) to protect against liver injury. MT is anti-inflammatory, decreases fibrosis and promotes liver regeneration. Recent research showed that MT expression in the liver decreases fibrosis in dogs affected by hepatitis, and a similar study evaluating liver disease in horses is also underway.
Because researchers have a poor understanding of liver function in cats, no one has explored the option of using MT to treat liver disease in the species. WCVM researcher Dr. Ahmad Al-Dissi has created a study that will measure the effect of MT on the liver defence mechanisms of cats with inflammatory liver disease.
In this study, researchers will use archived tissue samples from 30 cats that were diagnosed with inflammatory liver disease. They will compare levels of MT between normal and diseased liver samples and correlate these with abnormal changes often seen in the liver. While the study’s results will give veterinarians a better understanding of liver defence mechanisms in cats, it will also open doors for future use of MT as a treatment of inflammatory liver disease in cats.
Is pulse oximetry reliable for measuring oxygen levels in anesthetized patients?
Dr. Tanya Duke, WCVM
It’s essential to constantly monitor patients under anesthesia because these real-time physiological measurements allow clinicians to make informed decisions while managing their patients. But since inaccurate information can lead to incorrect decisions about patient management, it’s vital that monitors undergo regular testing.
Veterinarians consider a non-invasive method called pulse oximetry as a reliable way to monitor oxygen levels in their patients, but certain drugs may affect the accuracy of this method. Using nitrous oxide – which has pain-relieving properties and is used during surgery to diminish physiological responses – can cause erroneously low oxygen measurements in dogs, often resulting in a termination of nitrous oxide delivery.
Dr. Tanya Duke will lead a team in research to determine reliability of the pulse oximetry method during nitrous oxide administration in dogs. The project will determine if the pulse oximetry measurements are correct or whether they are created by changes in the delivery of oxygen to the blood due to the use of nitrous oxide.
The study will compare pulse oximetry measurements to arterial blood gas measurements obtained from samples taken before and after administration of nitrous oxide. This research will help determine whether pulse oximetry measurements are reliable and could result in more effective monitoring and pain management in canine patients undergoing surgery.
Improving diagnostic tools for the treatment of dogs in emergency situations
Drs. Matthew (Casey) Gaunt, Dr. Alison Khoo, Anthony Carr, WCVM
Administration of fluid therapy remains the cornerstone of treatment for veterinary patients in emergency settings. During emergencies, it can be difficult for veterinarians to distinguish whether a canine patient is suffering from a disease affecting the heart or the lungs. Trouble breathing can indicate chronic respiratory disease, cardiac problems – or both.
As a diagnostic tool, researchers have turned their attention to the presence of cardiac biomarkers — proteins or molecules in the bloodstream that could confirm a diagnosis of heart failure. B-type natriuretic peptide (BNP) is a biomarker that’s produced when the heart muscle is stretched. Presence of this protein can indicate heart problems, but some studies have shown elevation of BNP in patients without heart disease, which could be attributed to fluid therapy. Ultimately, it’s important to accurately diagnose the problem because incorrect treatment for one condition could worsen the other.
A research team led by Dr. Casey Gaunt will attempt to determine whether different treatments have different effects on the presence of BNP. Working with a group of six healthy dogs, the team will administer three different types of fluid therapy and measure the effect of each treatment on BNP levels in the dogs’ blood.
Researchers expect that all three methods will elevate BNP levels. Even if no changes in BNP levels occur, these results are still significant since they may validate the use of BNP as a diagnostic tool.
Can a novel tool for assessing clotting in whole blood help improve emergency treatment for dogs?
Drs. Marion Jackson, Sunita Seshia, Matthew (Casey) Gaunt and Anthony Carr, WCVM
The use of intravenous fluid therapy in veterinary medicine is essential. Veterinarians rely on fluids to treat their patients for dehydration, low blood pressure and to help the tissues continue to receive blood flow during anesthesia. Although essential, studies have shown the solutions used in fluid therapy may have the adverse effect of dilution of the blood and impair the blood’s ability to properly clot.
A novel diagnostic tool called rotational thromboelastometry (ROTEM) will help to determine the effect of fluid therapy on blood clotting. ROTEM measures clot formation in whole blood. Human researchers have used thromboelastometry (TEM) in studies on the effects of colloids on blood clotting, and now, Dr. Marion Jackson’s team will apply it to veterinary patients.
The WCVM researchers will use ROTEM to determine the effect of different intravenous fluids on whole blood clotting in dogs. They will administer three different fluid protocols used regularly in emergency situations to six healthy dogs.
The WCVM team believes that the resuscitative fluid therapy techniques will result in impaired clotting, and they also anticipate differences depending on the type of fluid used. Ultimately, the findings from this study will provide clinicians with a better understanding of resuscitative fluid effects on hemostasis, as measured by TEM.
A new cost-effective method for accurately positioning dogs during radiation therapy
Drs. Monique Mayer, Candace Lowe, Cheryl Waldner, Vivian Fan and Rachel Bloomfield (WCVM); Dr. Narinder Sidhu, British Columbia Cancer Agency; Dr. Susan LaRue, Colorado State University
As animals experience longer lives, cancer has become the leading cause of death for older dogs. In response, cancer treatments for animals have improved immensely due to developments in veterinary radiation therapy. The options have increased and owners are starting to ask for new treatments such as stereotactic body radiation therapy (SRT) that use highly targeted radiation beams. In particular, dog owners whose animals have brain and nasal cancers are demanding these new types of treatment.
However, many facilities do not have costly on-board imaging systems or positioning software that are essential to ensure proper positioning of the canine patient before using SRT and other new treatments.
A study led by Dr. Monique Mayer will investigate an alternate system of marking head position that can be temporarily attached to the teeth of dogs and allow accurate head positioning for patients receiving radiation therapy.
If their results show that this marker system is accurate, animals could receive new treatment techniques that reduce side effects, can increase tumour control rates and require significantly less treatment time. They could also save treatment centres the hundreds of thousands of dollars required to upgrade imaging systems.
Is radiation therapy the right decision for your pet?
Drs. Monique Mayer, Candace Lowe, Cheryl Waldner, Vivian Fan and Rachel Bloomfield (WCVM); Dr. Narinder Sidhu, British Columbia Cancer Agency; and Dr. Susan LaRue, Colorado State University
Forty-five per cent of animals treated with radiation at WCVM are palliative patients. Despite the frequent use of radiation therapy to alleviate pain in pets with incurable tumours, very little scientific literature exists measuring the improvement in quality of life for pets after palliative radiation therapy.
A team of researchers led by Dr. Monique Mayer will conduct a survey study to address this lack of information through collaboration with facilities in the United States and Canada. They will conduct studies with families of pets undergoing palliative radiation therapy to determine owner satisfaction and to improve the ability of veterinarians to guide families in this treatment option.
This study will help owners and veterinarians more accurately determine the best treatment for cancer patients at the end of their lives.
Can a non-invasive imaging tool help to accurately diagnose retinal conditions?
Drs. Lynne Sandmeyer, Bianca Bauer, Bruce Grahn and Marina Simair, WCVM
Retinal dysplasia is a common inherited disorder in all breeds of dogs, and in severe cases, the condition can lead to blindness. At the same time, retinal dysplasia can be difficult to differentiate from other conditions affecting the retina that may not be passed on through breeding.
Because retinal dysplasia is hereditary, a diagnosis of the condition can result in a recommendation not to breed the animal. A proper diagnosis allows breeders to make informed decisions about their breeding animals’ reproductive future. However, the current method of achieving a definitive diagnosis of retinal dysplasia involves microscopic examination that requires removal of the eye.
Dr. Lynne Sandmeyer and her team will study retinal dysplasia in live dogs using a non-invasive, non-contact diagnostic tool called optical coherence tomography (OCT). The imaging modality has been used in humans but is fairly new to veterinary medicine. This technique will allow researchers to produce high-resolution images of the eye, similar to what is seen by looking under a microscope. OCT may allow researchers to discern whether the animal has retinal dysplasia or a similar-looking condition.
Using cadavers, the WCVM research team will also compare OCT images of normal retinas to those images produced by looking under a microscope — providing a frame of reference for normal retinal appearance using OCT imaging. This will also help future researchers understand what a normal retina looks like using OCT.
Could nesfatin-1 be a useful marker of diabetic remission in cats?
Drs. Elisabeth Snead, Melissa Meachem and Suraj Unniappan, WCVM
Obesity in cats is a growing problem, and as a result, feline diabetes is also on the rise. The good news is that up to 80 per cent of newly-diagnosed diabetic cats can enter diabetic remission with insulin therapy and a high protein diet. However, veterinarians lack a reliable tool to determine how individual cats will respond to this treatment and properly predict remission.
A newly-discovered hormone called nesfatin-1 is shown to be important in regulating food intake and blood sugar levels in people. Elevated levels of the hormone have been connected with insulin resistance in obese and diabetic people. In addition, nesfatin-1 levels decrease significantly with remission of human type 2 diabetes.
Because feline diabetes shares many features with human diabetes, researchers see measurement of nesfatin-1 in cats as a potentially useful marker of remission of feline diabetes.
Dr. Elisabeth Snead and her team will evaluate levels of the hormone in normal weight, obese and diabetic cats. For part of the study, researchers will use tissue samples collected from an earlier study on feline obesity and diabetes as well as those collected from deceased cats.
If the study’s results show that nesfatin-1 is a useful marker of feline diabetic remission, the hormone may also show promise as a potential pharmaceutical treatment for feline obesity and diabetes.