Lipoproteins are biochemical assemblies that transport hydrophobic lipid molecules in water, such as in blood plasma or other extracellular fluids. They are complex particles that have a central hydrophobic core of non-polar lipids, primarily cholesteryl esters and triglycerides, surrounded by a hydrophilic membrane consisting of phospholipids, free cholesterol, and apolipoproteins. Lipoproteins are important for carrying triglycerides and cholesterol through the bloodstream for use throughout the body. There are different types of lipoproteins, which are categorized based on their size, biological role, and contents. The main types of lipoproteins are:
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Chylomicrons: These are large, triglyceride-rich lipoproteins that intestinal cells produce from dietary fats.
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Very low-density lipoproteins (VLDL): The liver produces these triglyceride-rich particles, which are smaller than chylomicrons, though their size can vary.
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Intermediate density lipoproteins (IDL): These carry cholesterol and triglycerides.
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Low-density lipoproteins (LDL): These are the main carrier of cholesterol in the blood and they deliver to cholesterol-dependent tissues, such as the adrenal glands and the gonads.
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High-density lipoproteins (HDL): These collect fat molecules from the bodys cells/tissues and take them back to the liver. HDLs are sometimes referred to as "good" lipoprotein because higher concentrations correlate with low rates of atherosclerosis progression and/or regression.
Lipoprotein (a) or LP(a) is a type of LDL that carries cholesterol to the cells in the arteries. High levels of LP(a) are a risk factor for atherosclerosis, which can lead to serious medical conditions such as coronary artery disease, heart attack, and stroke.
