Hometown: Knoxville, Tennessee
Major: Biology (pre-vet)
Thesis Title: The Comparison of the Effect of Dietary Changes or Dirlotapide Treatment on Canine Obesity in a Small Animal Veterinary Practice
Advisor: Dr. Drew Crain


Thesis Abstract

Anna McRee ’10

Hometown: Knoxville, Tennessee
Major: Biology (pre-vet)
Thesis Title: The Comparison of the Effect of Dietary Changes or Dirlotapide Treatment on Canine Obesity in a Small Animal Veterinary Practice
Advisor: Dr. Drew Crain

‘Tis the season for “packing on the pounds” for many Americans. But what about man’s best friend?

Before sharing leftovers with the furriest member of the family, consider the research findings of Maryville College senior Anna McRee.

The Rock Hill, S.C., native moved to Knoxville, Tenn., during her junior year of high school. After graduating from Farragut High School in 2006, she began working as a veterinary assistant at a small clinic.

But she heard the call of veterinary medicine years before.

“I was the inquisitive kindergartner who proudly declared that I wanted to be a veterinarian,” McRee recalls. “But a simple love of creatures was not the sole driving force behind my career choice… I have a passion for life and fulfillment of purpose that has only grown in fervor as I’ve matured.”

She learned a valuable life lesson: “Often, to relieve greater suffering, we must encounter pain,” she shared. “But, it is in the heart of healing, of caring, of tending, that I have found the most fulfilling joy.”

Needless to say, focusing on a veterinary issue for her Senior Study came naturally for McRee, who is majoring in biology.

She selected canine obesity after she observed this topic of growing concern at the small animal veterinary practice where she currently works.

“Little research has been conducted on this topic, and it was manageable for the year-long study,” said Dr. Drew Crain, associate professor of biology and McRee’s Senior Study advisor.

In her 54-page study, McRee evaluated the incidence of obesity at My Pet’s Animal Hospital, a small animal veterinary practice in Knoxville, Tenn., and assessed the efficacy of two treatment tools: medication and dietary intervention.

Obesity was measured by recording the Canine Body Condition Score (BCS) on a scale of one through nine for every dog that entered the clinic over a two-month period. A score of six or seven indicated that the dog was overweight; a score greater than seven indicated obesity, or a weight at least 15% above the ideal.

Data was collected for 594 dogs to determine incidence of obesity. Four treatment groups (comprised of 134 dogs total) were evaluated to examine the effectiveness of three treatment options. One group was treated with the newly-released pharmaceutical agent dirlotapide; one was treated with a restricted-calorie diet; another was assigned a specially formulated high fiber diet; and the fourth group acted as the control, receiving no treatment.

Each dog’s weight was recorded at the beginning of the study, during treatment and at the conclusion of treatment.

According to McRee, one of the most promising canine medications today is dirlotapide, manufactured by Pfizer Inc. It is a “microsomal triglyceride transfer protein (MTP) inhibitor that acts primarily within the endoplasmic reticulum of enterocyte intestinal cells, preventing the formation and release of chylomicrons into the lymphatic circulation and reduces food intake in dogs.”

Basically, MTP inhibitors, such as dirlotapide have the ability to lower triglyceride concentrations and plasma cholesterol, reducing intestinal fat absorption.

McRee’s study presented two major findings: 1) 67% of dogs at the vet clinic were overweight/obese, and 2) both dietary changes and pharmaceutical treatment were equally effective in promoting a healthy percent of weight loss over a 30-day period in obese canines. The control group actually gained weight, illustrating that therapy is necessary to induce weight loss, she concluded.

“It was interesting to note the dynamics between people and their pets. Most didn’t realize that their dogs were overfed or obese,” observed McRee.

In her thesis, she said, “The knowledge obtained from this study and the flexibility it provides for treatment options will hopefully reduce the prevalence of canine obesity.”

According to McRee, the most challenging part of the study was determining the logistics – what angle to approach the topic. The data collection process was also tedious.

“It was hard not to become overwhelmed with how big the project was,” said McRee. “I like to sit down and get something done. You can’t do that with a year-long project. I grew a lot through the process.”

Crain added, “Deferred gratification is the difficult part of a long-term project. When you’re in the midst of it, it’s hard to see a positive, fruitful outcome.”

McRee and Crain were confident in being able to determine the incidence of obesity. The challenge lay with obtaining repeated measures on individual dogs that were in the treatment groups.

“We were unsure if the dog owners would comply with the treatment for at least two months, or if they would even bring their dogs back for follow-up,” he explained. “Thankfully, they did.”

Impressed with the final result, Crain recommended McRee’s thesis for the College’s permanent library collection.

He pointed out that a good thesis consists of several components: a unique and important question, meticulous collection of data and successfully bringing data together to answer the question.

“Anna’s study has all of these components. She generated her own data, analyzed and presented it. She grew in her ability to utilize data to answer her thesis question. And she is a good, thorough writer. She now has a wonderful document to submit for publication,” he raved. (They opted to submit the study to the journal Bios.)

Crain noted that his job in the study was to ensure that the scientific process was complete, that there were no fatal flaws in the experimental design.

“The most successful, effective and important research projects are collaborative. That is modeled perfectly by our Senior Study Program,” he commented.

While completing her final year at Maryville College, McRee works part-time at My Pet’s Animal Hospital. Anticipating fall enrollment, she has applied to the veterinarian schools at the University of Tennessee and Auburn University.

According to Crain, one of the greatest benefits of McRee’s thesis has yet to transpire.

“When Anna interviews at vet schools and talks about the study, she will set herself apart from the other students by showing her excellence as scientist,” he commented.

McRee said that the Senior Study experience has confirmed that she is on the right vocational path. While still unsure of an area of specialization, she expressed her openness to different specialties within the field of veterinary medicine.

“I am immensely intrigued by exotic medicine. I would love to be part of research expeditions or on staff at a zoological park, caring for species so that the rest of the world can learn from them,” she shared.