A recent study funded by the American Heart Association on longevity unexpectedly took a turn and found an explanation for why some people who consume excessive calories don’t gain weight, says a recent press release by the Mayo Clinic in Rochester, Minn.
The Mayo Clinic web site states the study will appear in the November issue of the Federation of American Societies for Experimental Biology Journal.
The press release says that prior research in animal models has shown that restricted calories can lower cholesterol and blood pressure, both generally considered the biomarkers of aging. Published research has also shown that reduced caloric intake can turn on the SIRT1 gene, one of a family of seven genes linked to longevity.
Other studies have shown that the chemical receptor PGC1 plays a key role in obesity and metabolism. Research found that the SIRT genes activate PGC1 and in doing so, can offset the negative effects of obesity in mice. However, until this recent Mayo Clinic study, how the SIRT-PGC1 reaction works has not been understood or explained.
The press release says that in previous lab animal studies by the Mayo Clinic, gene CD38 was shown to be involved in regulating energy metabolism. Recent studies in humans also show a possible connection between CD38 and metabolism, specifically metabolic syndrome. Metabolic syndrome includes metabolic-related health issues that usually afflict people who are obese. These health issues include high blood pressure, elevated insulin levels and high cholesterol levels.
In this study, which was done in lab mouse models, researchers investigated and confirmed that CD38 inhibits SIRT and the expression of PGC1 in mouse models and, as a result, regulates body weight. In the absence of CD38, the SIRT-PGC1 pathway was activated and protected mice models from developing obesity. In other words, without the CD38 gene, mice on high fat diets did not gain weight. The mice burned more energy, were leaner and otherwise healthy. When the CD38 gene was present, the mice became obese.
Dr. Eduardo Chini is a Mayo Clinic anesthesiologist and author of the study. In the press release he is quoted as saying, “These changes contributed to the ability of these mice to fend off weight gain despite a high-fat diet and lack of exercise. Together these results suggest that a CD38 deficiency has a protective effect against high-fat, diet-induced obesity.”
Dr. Chini also said that “obesity is a complex problem compounded by multiple factors, one of which is our genes. Genes play a role in about 50 percent of cases, and in this study, we demonstrate that CD38 regulates body weight.”
According to the press release, Dr. Chini believes that identifying the signaling mechanisms that lead to obesity caused by high fat, high calorie diets is a critical part of understanding and developing new obesity treatments.
Mayo Clinic, Gene Deficiency is a Protective Barrier to Obesity; http://www.mayoclinic.org/news2007-rst/4114.html