Remnant Lipoproteins: Measurement and Clinical Significance (Editorial‪)‬

In this issue of the Journal, Chan et al. (1) make the significant observation, by three distinct measures, that the concentrations of remnant lipoproteins (RLPs) in plasma are increased in patients with obesity. This increase in RLPs could explain, in part, the increased cardiovascular risk associated with obesity (2). To date, although LDL- and HDL-cholesterol are clearly accepted as independent risk factors for premature atherosclerosis, the role of plasma triglycerides as a risk factor remains somewhat controversial. Plasma triglycerides are clearly a measure of triglyceride-rich lipoproteins (TRLs), which derive from both the intestine and the liver. Measurement of plasma triglycerides, however, does not distinguish the various subspecies of TRLs, which clearly have various degrees of atherogenicity. Triglyceride-rich RLPs are formed in the circulation when chylomicrons of intestinal origin [with apolipoprotein B-48 (apo B-48)] and VLDL of hepatic origin (with apo B-100) are converted by lipoprotein lipase (and to a lesser extent by hepatic lipase) into smaller and more dense particles. Compared with their nascent precursors, RLPs are depleted of triglycerides, phospholipids, and apo C and are enriched in cholesteryl esters and apo E and are believed to be more atherogenic than the larger TRLs (3).