Researchers find new links between obesity and cardiovascular disease

In a new study published in the Journal of Biological Chemistry, a research group led by James A. Hamilton, PhD, professor of Physiology, Biophysics and Radiology at Boston University School of Medicine, applied novel methods to detect binding of fatty acids to CD36 and their effect on internalization of oxidized LDL. Although other research groups have characterized a fatty acid binding site on CD36 and postulated CD36 to be a gatekeeper for fatty acid entry into cells, the Hamilton lab previously found that CD36 did not increase fatty acid translocation across the plasma membrane.

In the current study all of the common dietary fatty acid types (saturated, unsaturated, trans and polyunsaturated) were shown by a new assay to bind to CD36 at levels greater than expected for a single binding site characterized in previous studies. In cells with CD36 present in the plasma membrane, all of the fatty acids also enhanced oxidized LDL uptake, except for the fish oil fatty acid DHA. This current study adds to the possible mechanisms for fish oil benefits that are now widely recognized.

"Since obesity and type 2 diabetes are characterized by high plasma levels of fatty acids, the demonstrated enhancement of oxLDL uptake by increases in common dietary fatty acids may contribute to the pathophysiology of these diseases. Furthermore, our new results provided a link between fatty acids, CD36, and atherosclerosis and new drugs can be designed that target the exact mechanism more precisely." added Hamilton.

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The work was supported by a grant from the American Diabetes Association. The study's co-authors are Anthony Jay, Alex Chen, Justin Hung, and Miguel Paz.

Obesity and Cardiovascular Disease: Risk Factor, Paradox, and Impact of Weight Loss

Obesity has reached global epidemic proportions in both adults and children and is associated with numerous comorbidities, including hypertension (HTN), type II diabetes mellitus, dyslipidemia, obstructive sleep apnea and sleep-disordered breathing, certain cancers, and major cardiovascular (CV) diseases. Because of its maladaptive effects on various CV risk factors and its adverse effects on CV structure and function, obesity has a major impact on CV diseases, such as heart failure (HF), coronary heart disease (CHD), sudden cardiac death, and atrial fibrillation, and is associated with reduced overall survival. Despite this adverse association, numerous studies have documented an obesity paradox in which overweight and obese people with established CV disease, including HTN, HF, CHD, and peripheral arterial disease, have a better prognosis compared with nonoverweight/nonobese patients. This review summarizes the adverse effects of obesity on CV disease risk factors and its role in the pathogenesis of various CV diseases, reviews the obesity paradox and potential explanations for these puzzling data, and concludes with a discussion regarding the current state of weight reduction in the prevention and treatment of CV diseases.