Apolipoprotein-B (apoB)
Every single lipoprotein (LDL, VLDL, IDL) that contributes to atherosclerosis—carries this apoB protein signature.
So to gauge the true extent of your [cardivascular] risk, we have to know how many of these apoB particles are circulating in your bloodstream. That number is much more relevant than the total quantity of cholesterol that these particles are carrying. - Outlive see Atherosclerosis
Amount of cholesterol >2-fold per apoB particle.
- LDL is wrapped by 1-apoB particle.
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the amount of cholesterol per LDL particle varies >2-fold between individuals - pmc.nih.gov
- Hence, the amount of cholesterol per apoB particle varries >2-fold. And each separate apoB particle presents risk, not total cholesterol. Therefore we should measure apoB not just LDL/HDL.
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The reason they're called high- and low-density lipoprotein (HDL = High-Density Lipoprotein and LDL = Low-Density Lipoprotein, respectively) has to do with the amount of fat relative to protein that each one carries. LDLs carry more lipids, while HDLs carry more protein in relation to fat, and are therefore more dense.
Also, these particles (and other lipoproteins) frequently exchange cargo with one another, which is part of what drives me crazy about labeling them "good" and "bad." When an HDL transfers its "good cholesterol" to an LDL particle, does that cholesterol suddenly become "bad"?
The answer is no—because it's not the cholesterol per se that causes problems but the nature of the particle in which it's transported. Each lipoprotein particle is enwrapped by one or more large molecules, called apolipoproteins, that provide structure, stability, and, most importantly, solubility to the particle.
HDL particles are wrapped in a type of molecule called apolipoprotein A (or apoA), while LDL is encased in apolipoprotein B (or apoB). This distinction may seem trivial, but it goes to the very root cause of atherosclerotic disease: every single lipoprotein that contributes to atherosclerosis—not only LDL but several others—carries this apoB protein signature. - Outlive
There are also very-low-density lipoproteins, or VLDLs, which we mentioned in the previous chapter, as well as intermediate-density lipoproteins, or IDLs. These carry even more fat than the LDLs, much of it in the form of triglycerides, and they are also marked with apoB. Also: While HDL particles have multiple apoAs, each LDL (or VLDL, or IDL) has only one apoB particle, making it relatively easy to measure their concentration. - Outlive
Relationships
- wraps:LDL = Low-Density Lipoprotein
- wraps:VLDL = Very Low-Density Lipoprotein)
- wraps:IDL = Intermediate-density Lipoprotein
Notes
High levels of apolipoprotein B (apoB) have been shown to predict atherosclerotic cardiovascular disease (CVD) in adults even in the context of low levels of low-density lipoprotein cholesterol (LDL-C) - pubmed.nih.gov
Children
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