White fat is the “bad” gut fat associated with obesity and enlarged abdomens. When a pound of new white fat forms in the body, it requires a full mile of new blood vessels to nourish and sustain it. That’s because white fat is much like a tumor in requiring a steady blood supply. To build the new blood vessels, it depends on a process called angiogenesis.
Using the tumor analogy, researchers at the University of Cincinnati’s Metabolic Diseases Institute wondered what would happen if they attacked white fat by cutting off its blood supply and starving it. To find the answer, they used a proapoptotic (literally, “leading to death”) peptide* targeted at the blood vessels in white fat. They found that without its blood supply, the fat “starved” and began to disappear.
The researchers treated both obese and lean rats and mice with the proapoptotic peptide for periods of four or 27 days, monitoring their food intake and energy levels. Some of the rodents, already obese, had been on high-fat diets to make them overweight. Others, not obese, were placed on high-fat diets for purposes of the study. Another group of non-obese mice and rats were on low-fat diets.
The researchers found that the peptide totally reversed the diet-induced obesity of the already obese mice, and it reduced the weight of the other rodents that had been recently placed on high-fat diets. The peptide had no effect on the mice and rats on the low-fat diet. The researchers also found that although the peptide lowered the appetite and food intake among the obese and high-fat-diet rodents, it did not affect their energy levels. Despite consuming less food, the mice and rats did not experience a drop-off in their expenditures of energy.
The study’s findings, published in the January 26, 2010, issue of Diabetes, the journal of the American Diabetes Association, opens the way to a possible new therapy for treating obesity. Obesity, along with other factors, such as high blood pressure, is often a precursor to type 2 diabetes and cardiovascular problems.
*Peptides, which are compounds consisting of two or more amino acids, are the building blocks of proteins.