Link Between Inflammation and Obesity Becomes More Clear
Australian researchers may have found the biological key to preventing and treating obesity. The study authors think the findings could lead to an “obesity drug” sooner rather than later, helping bring many closer to their ideal weight which in turn could prevent such obesity-related conditions such as Type 2 diabetes, heart disease and certain cancers.
Globally, there are more than 1 billion overweight adults, per the World Health Organization. About 300 million of them are obese (BMI greater than 30).
Poor diet and lack of exercise contribute to excess body fat, but those two conditions alone do not adequately explain the rapid increase in obesity rates in the United States and other parts of the developed world. One theory is that inflammation in response to excess calories causes disruption within certain tissues, including adipose (fat cells).
It was once thought that fat cells were simply storage for energy that could be used by the body at a later time. However, we now know that these cells are a critical component of metabolic control, including acting as an inflammatory mediator.
Seemingly confirming this link, University of Queensland researchers have discovered that obese and overweight fat tissue contains disproportionate amount of a specific inflammatory protein known as protease-activated receptor 2. PAR2 modulates inflammatory responses, especially during times of infection. Notably, it is activated by a digestive compound known as trypsin.
Excess food intake, especially consuming too much fat and sugar, triggers the fat cell dysfunction and the start of the inflammatory process. Thus, PAR2 may become a biomarker for obesity and metabolic dysfunction.
Senior author David Fairlie believes that the discovery could also lead to a new target for anti-obesity drug producers. For the study, rats fed a high-carbohydrate, high-fat diet for 16 weeks to bring about obesity and inflammation were then given a PAR2 antagonist currently known as GB88 which lead to a 10% body weight reduction.
“Drugs designed to block certain inflammatory proteins, says Dr. Fairlie, “may be able to prevent and treat obesity, which in turn is a major risk factor for type 2 diabetes, heart disease, stroke, kidney failure, limb amputation, and cancers."
Gerard Weissman, editor-in-chief of FASEB Journal, told reporters. “The bottom line of this report is that obesity is an inflammatory disease, and inflammation plays a greater role in the downward spiral to obesity than most people realize.”
"It appears that once we can control the inflammation, we can begin to get everything else in line,” Weissmann concluded. “Fortunately, these scientists have already identified one promising compound that seems to work."
Of course, you can take control of inflammation on your own without drugs, says Dr. Russell Greenfield MD, an assistant professor of medicine at the University of North Carolina at Chapel Hill. A change in diet can be helpful, specifically, cutting back on the amount of “unhealthy” fats (those from processed and fast foods), trading refined carbohydrates (white pasta, white rice) for whole grains, and eating plenty of fruits, vegetables, and sources of omega-3 fatty acids (fish, walnuts.)
Not surprisingly, an anti-inflammatory diet will takes longer to work than an anti-inflammatory medicine. "With an anti-inflammatory drug, you feel better in an hour or two," Dr. Greenfield says. However, "I would say clearly within just a few weeks most of the patients I have see a noticeable difference [in symptoms]."
Source: Junxian Lim, David P. Fairlie et al. Diet-induced obesity, adipose inflammation, and metabolic dysfunction correlating with PAR2 expression are attenuated by PAR2 antagonism. FASEB J December 2013 27:4757-4767; doi:10.1096/fj.13-232702
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