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Why heart attacks can still happen even when bad cholesterol is low

from ScienceDaily

Even when bad cholesterol is brought down to healthy levels, some people remain at risk of heart attacks, and scientists may have discovered why. Researchers identified two types of fat-carrying particles that appear to promote inflammation and damage blood vessels through mechanisms beyond cholesterol buildup.

explained

A lipoprotein is a biochemical assembly whose primary function is to transport hydrophobic lipid (also known as fat) molecules in water, as in blood plasma or other extracellular fluids. They consist of a triglyceride and cholesterol center, surrounded by a phospholipid outer shell, with the hydrophilic portions oriented outward toward the surrounding water and lipophilic portions oriented inward toward the lipid center. A special kind of protein, called apolipoprotein, is embedded in the outer shell, both stabilising the complex and giving it a functional identity that determines its role.

Plasma lipoprotein particles are commonly divided into five main classes, based on size, lipid composition, and apolipoprotein content. They are, in increasing size order: HDL, LDL, IDL, VLDL and chylomicrons. Subgroups of these plasma particles are primary drivers or modulators of atherosclerosis.

Many enzymes, transporters, structural proteins, antigens, adhesins, and toxins are sometimes also classified as lipoproteins, since they are formed by lipids and proteins.

From Wikipedia: Lipoprotein (CC BY-SA 4.0) ↗ · text CC BY-SA 4.0
how it works

Blood vessels can be damaged when certain lipoprotein particles trigger inflammation in artery walls, which makes plaques grow and rupture. Lowering LDL cholesterol removes one trigger but leaves others untouched.

so what

It suggests that LDL alone is an incomplete risk measure. Future tests and drugs may target these particles and inflammation, not only cholesterol.

fun fact

Cholesterol is carried in the blood inside particles called lipoproteins because fat does not mix with water.

more on this

Illustrative photo · AntiSense, CC BY-SA 3.0, via Wikimedia Commons