The Concept of CMR

Overview

Atherogenic dyslipidemia is one of the metabolic abnormalities that define the metabolic syndrome, the cluster of cardiovascular risk factors frequently associated with intra-abdominal (or visceral) obesity. This section outlines the components of the dyslipidemia that characterizes intra-abdominal obesity and the metabolic syndrome, as well as their causes and impact on cardiovascular disease (CVD) risk. A brief review of the intravascular lipid transport system will help place the dyslipidemia of intra-abdominal obesity in proper context.

The major lipids involved in dyslipidemia are cholesterol and triglycerides. These lipids are insoluble in blood (like oil in water) and must be packaged into macromolecular lipid-protein complexes called lipoproteins for export to other organs (Figure 1). Lipoproteins are classified according to their lipid and protein composition. The major lipoprotein classes are as follows: chylomicrons, very-low-density lipoproteins (VLDL), remnants (or intermediate-density lipoproteins, IDL), low-density lipoproteins (LDL), and high-density lipoproteins (HDL). Chylomicrons and VLDL are the main transporters of dietary and endogenous triglycerides respectively, while LDL and HDL mainly carry cholesterol between the liver and extrahepatic tissues (1-4). Following is a brief, simplified overview of the metabolic fate of each of these lipoprotein families (Figures 2 & 3).