Obesity has become an epidemic throughout the United States over the last decade. Medical professionals, political figures, health advocates, and even the First Lady are all attempting to put an end to the spread of obesity.

The pre-clinical research sector is also studying the link between energy intake and expenditure to have a greater understanding of obesity. Obesity results from a larger intake of energy and a much smaller expenditure of this same energy, which is then stored as body lipids.

A study from the UK-based University of Aberdeen published in the Laboratory Animals journal discussed how animal models have provided a clear method for learning about the energy balance of biological systems. The paper explains that gene mutations and genetic disruptions increase the risk of obesity in animal models.

Genetic Causes

It has been found that random single gene loss-of-function mutations lead to widespread obesity. In an obesity animal model study, a defect was found in the ob/ob mouse in the form of a single base pair deletion. The completion of sequencing mouse and rat genomes along with the creation of high throughput sequencing technology has streamlined the study of new mutations or genetic defects.

Over the years, scientists have discovered at least 10 single gene loss-of-function defects in animal models that lead to massive obesity. Additionally, this research has led to a greater understanding of how the human energy regulation system functions.

Effect of Diet

Many animal model studies have also discovered the response of rodents to high fat and/or high sugar diets and the effect of food restrictions on the overall mass and fat loss of an animal. Additionally, certain pharmaceutical medications have been used on animal models to determine how it affects energy balance and obesity. Past research has uncovered that the cytokine hormone leptin and its receptor play a significant role in obesity development.

Studying Obesity in Dog Models

Along with rodent models, dogs have also been used to study satiety signals and discover the pancreatic regulatory hormone insulin. By the mid-1980s, domestic dogs were found to be significantly overweight and obese in veterinary clinics, with as many as 25 percent classified in the obese range. With a majority of the dog physiology already discovered and its genome completely mapped, this animal model is a prime example for a human obesity comparison. It is predicted that dog models will be useful in the near future for studying the spread of obesity.

Utilizing Non-human Primate Models

While mice and rats are some of the most common animals used in preclinical research, Old World monkeys such as macaques, the rhesus monkey, baboons, and other apes are more closely related to the human species. This provides a better comparison when studying obesity levels in humans.

Several species have illustrated that obesity may be related to age even when maintained on a low-fat diet. These primates were also put on high-fat diets to uncover any relation to obesity. Additionally, epigenetic effects were analyzed in the Old World monkeys to connect to weight gain in humans.

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Categories: Obesity

Tags: animal models, dog models, obesity studies, primate models