Low-density lipoprotein: Difference between revisions

Latest revision as of 12:05, 15 February 2025

Low-density lipoprotein

Atheroma formation in an artery

Low-density lipoprotein (LDL) is one of the five major groups of lipoproteins that transport all fat molecules throughout the body in the extracellular water. These groups, from least dense to most dense, are chylomicrons, very low-density lipoproteins (VLDL), intermediate-density lipoproteins (IDL), low-density lipoproteins (LDL), and high-density lipoproteins (HDL).

Structure[edit]

LDL particles are the major carriers of cholesterol in the blood. They are composed of a core of cholesteryl esters and triglycerides, surrounded by a shell of phospholipids, free cholesterol, and apolipoprotein B-100. The size of LDL particles can vary, and smaller, denser LDL particles are considered more atherogenic.

Function[edit]

The primary role of LDL is to transport cholesterol to peripheral tissues. Cells express LDL receptors on their surface, which bind to the apolipoprotein B-100 on LDL particles, allowing them to be internalized and utilized for membrane synthesis and other functions.

Clinical significance[edit]

Elevated levels of LDL cholesterol are associated with an increased risk of atherosclerosis, a condition characterized by the buildup of fatty deposits, or plaques, within the walls of arteries. This can lead to coronary artery disease, stroke, and other cardiovascular diseases.

Atheroma formation[edit]

File:Atheroma.jpg

Atheroma formation in an artery

Atheromas, or plaques, form when LDL particles penetrate the endothelial lining of arteries and become oxidized. This triggers an inflammatory response, attracting macrophages that engulf the oxidized LDL, becoming foam cells. Over time, these foam cells accumulate, forming the core of the atheroma.

Management[edit]

Management of elevated LDL cholesterol involves lifestyle modifications such as diet and exercise, as well as pharmacological interventions. Statins are the most commonly prescribed medications for lowering LDL cholesterol levels. Other medications include ezetimibe, PCSK9 inhibitors, and bile acid sequestrants.

Related pages[edit]

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-'''Low-density lipoprotein (LDL)''' represents one of the principal lipoproteins involved in the transport of lipids within the body's extracellular fluid. LDL serves the primary function of conveying lipid molecules to cells, and its role is essential in various physiological processes. However, LDL has been closely associated with the process of atherosclerosis, a significant contributor to cardiovascular disease.
+Low-density lipoprotein
-== Classification of Lipoproteins ==
+[[File:Atheroma.jpg|thumb|right|Atheroma formation in an artery]]
-Lipoproteins are complex particles composed of core lipids, surrounded by phospholipids and apolipoproteins. These particles facilitate the transport of hydrophobic lipid molecules in the blood, which is primarily composed of water. They are classified based on their density into five major groups from least dense to most dense: [[chylomicrons]], [[very low-density lipoprotein (VLDL)]], [[intermediate-density lipoprotein (IDL)]], LDL, and [[high-density lipoprotein (HDL)]].
+Low-density lipoprotein (LDL) is one of the five major groups of [[lipoproteins]] that transport all fat molecules throughout the body in the extracellular water. These groups, from least dense to most dense, are [[chylomicrons]], very low-density lipoproteins (VLDL), intermediate-density lipoproteins (IDL), low-density lipoproteins (LDL), and high-density lipoproteins (HDL).
-== Structure and Function of LDL ==
+==Structure==
+LDL particles are the major carriers of [[cholesterol]] in the blood. They are composed of a core of [[cholesteryl esters]] and [[triglycerides]], surrounded by a shell of [[phospholipids]], free cholesterol, and [[apolipoprotein B-100]]. The size of LDL particles can vary, and smaller, denser LDL particles are considered more atherogenic.
-LDL particles are made up of a single molecule of [[apolipoprotein B-100]] and about 80% of their weight is composed of lipids, including cholesterol and triglycerides. LDL particles are characterized by a core of esterified cholesterol and triglycerides surrounded by a single layer of free cholesterol and phospholipids.
+==Function==
+The primary role of LDL is to transport cholesterol to peripheral tissues. Cells express [[LDL receptors]] on their surface, which bind to the apolipoprotein B-100 on LDL particles, allowing them to be internalized and utilized for membrane synthesis and other functions.
-The primary role of LDL is to transport cholesterol and other fats to peripheral tissues, where they are either used for cell membrane synthesis or stored in adipose tissue. The LDL particles bind to LDL receptors on the cell surface, are internalized and then the cholesterol is released for use by the cell.
+==Clinical significance==
+Elevated levels of LDL cholesterol are associated with an increased risk of [[atherosclerosis]], a condition characterized by the buildup of fatty deposits, or plaques, within the walls of arteries. This can lead to [[coronary artery disease]], [[stroke]], and other cardiovascular diseases.
-== LDL and Atherosclerosis ==
+===Atheroma formation===
+[[File:Atheroma.jpg|thumb|left|Atheroma formation in an artery]]
+Atheromas, or plaques, form when LDL particles penetrate the endothelial lining of arteries and become oxidized. This triggers an inflammatory response, attracting [[macrophages]] that engulf the oxidized LDL, becoming [[foam cells]]. Over time, these foam cells accumulate, forming the core of the atheroma.
-Despite its essential role, LDL is often referred to as "bad cholesterol" due to its role in atherosclerosis, a condition characterized by the build-up of plaque within the artery walls. This occurs when LDL particles become oxidized and initiate an inflammatory response, leading to the recruitment of monocytes and the formation of foam cells. Over time, this process leads to the development of atherosclerotic plaques, which can obstruct blood flow and contribute to the risk of heart attack or stroke.
+==Management==
+Management of elevated LDL cholesterol involves lifestyle modifications such as diet and exercise, as well as pharmacological interventions. [[Statins]] are the most commonly prescribed medications for lowering LDL cholesterol levels. Other medications include [[ezetimibe]], [[PCSK9 inhibitors]], and [[bile acid sequestrants]].
+==Related pages==
+* [[High-density lipoprotein]]
+* [[Cholesterol]]
+* [[Atherosclerosis]]
+* [[Cardiovascular disease]]
-== References ==
-* Feingold KR, Grunfeld C. Introduction to Lipids and Lipoproteins. [Updated 2021 Jul 26]. In: Feingold KR, Anawalt B, Boyce A, et al., editors. Endotext [Internet]. South Dartmouth (MA): MDText.com, Inc.; 2000-.
-* Tabas I, Williams KJ, Borén J. Subendothelial lipoprotein retention as the initiating process in atherosclerosis: update and therapeutic implications. Circulation. 2007 Oct 16;116(16):1832-44. doi: 10.1161/CIRCULATIONAHA.106.676890. PMID: 17938300.
-* Libby P, Buring JE, Badimon L, Hansson GK, Deanfield J, Bittencourt MS, Tokgözoğlu L, Lewis EF. Atherosclerosis. Nat Rev Dis Primers. 2019 Jun 20;5(1):56. doi: 10.1038/s41572-019-0106-z. PMID: 31222035.
-* Williams KJ, Tabas I. The response-to-retention hypothesis of early atherogenesis. Arterioscler Thromb Vasc Biol. 1995 May;15(5):551-61. doi: 10.1161/01.atv.15.5.551. PMID: 7749869.
-{{stub}}
-{{Lipoproteins}}
-{{Vascular diseases}}
-{{Portal bar|Biology}}
-{{DEFAULTSORT:Low-Density Lipoprotein}}
-[[Category:Cardiology]]
-[[Category:Lipid disorders]]
 [[Category:Lipoproteins]]