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Cholesterol is any of a class of certain organic molecules. A cholesterol is a sterol, a type of lipid. Cholesterol is biosynthesized by all animal cells and is an essential structural component of animal cell membranes. When chemically isolated, it is a yellowish crystalline solid.
Low-density lipoprotein (LDL) is one of the five major groups of lipoprotein which transport all fat molecules around the body in the extracellular water. These groups, from least dense to most dense, are chylomicrons, very low-density lipoprotein (VLDL), intermediate-density lipoprotein (IDL), low-density lipoprotein (LDL) and high-density lipoprotein (HDL). LDL delivers fat molecules to cells. LDL is involved in atherosclerosis, a process in which it is oxidized within the walls of arteries.
Hypercholesterolemia, also called high cholesterol, is the presence of high levels of cholesterol in the blood. It is a form of hyperlipidemia, hyperlipoproteinemia, and dyslipidemia.
Dyslipidemia is an abnormal amount of lipids in the blood. Dyslipidemia is a risk factor for the development of atherosclerotic cardiovascular disease (ASCVD). ASCVD includes coronary artery disease, cerbrovascular disease, and peripheral artery disease. Although dyslipidemia is a risk factor for ASCVD, abnormal levels doesn't mean that lipid lowering agents need to be started. Other factors, such as comorbid conditions and lifestyle in addition to dyslipidemia, is considered in a cardiovascular risk assessment. In developed countries, most dyslipidemias are hyperlipidemias; that is, an elevation of lipids in the blood. This is often due to diet and lifestyle. Prolonged elevation of insulin resistance can also lead to dyslipidemia. Likewise, increased levels of O-GlcNAc transferase (OGT) may cause dyslipidemia.
In medicine, LDL apheresis is a form of apheresis, resembling dialysis, to eliminate the cholesterol-containing particle low-density lipoprotein (LDL) from the bloodstream.
Combined hyperlipidemia is a commonly occurring form of hypercholesterolemia characterised by increased LDL and triglyceride concentrations, often accompanied by decreased HDL. On lipoprotein electrophoresis it shows as a hyperlipoproteinemia type IIB. It is the most commonly inherited lipid disorder, occurring in around one in 200 persons. In fact, almost one in five individuals who develop coronary heart disease before the age of 60 have this disorder.
Hyperlipidemia is abnormally elevated levels of any or all lipids or lipoproteins in the blood. The term hyperlipidemia refers to the laboratory finding itself and is also used as an umbrella term covering any of various acquired or genetic disorders that result in that finding. Hyperlipidemia represents a subset of dyslipidemia and a superset of hypercholesterolemia. Hyperlipidemia is usually chronic and requires ongoing medication to control blood lipid levels.
Michael Stuart Brown ForMemRS is an American geneticist and Nobel laureate. He was awarded the Nobel Prize in Physiology or Medicine with Joseph L. Goldstein in 1985 for describing the regulation of cholesterol metabolism.
The low-density lipoprotein (LDL) receptor (LDL-R) is a mosaic protein of 839 amino acids that mediates the endocytosis of cholesterol-rich LDL. It is a cell-surface receptor that recognizes the apoprotein B100, which is embedded in the outer phospholipid layer of LDL particles. The receptor also recognizes the apoE protein found in chylomicron remnants and VLDL remnants (IDL). In humans, the LDL receptor protein is encoded by the LDLR gene on chromosome 19. It belongs to the low density lipoprotein receptor gene family. It is most significantly expressed in bronchial epithelial cells and adrenal gland and cortex tissue.
The very-low-density-lipoprotein receptor (VLDLR) is a transmembrane lipoprotein receptor of the low-density-lipoprotein (LDL) receptor family. VLDLR shows considerable homology with the members of this lineage. Discovered in 1992 by T. Yamamoto, VLDLR is widely distributed throughout the tissues of the body, including the heart, skeletal muscle, adipose tissue, and the brain, but is absent from the liver. This receptor has an important role in cholesterol uptake, metabolism of apolipoprotein E-containing triacylglycerol-rich lipoproteins, and neuronal migration in the developing brain. In humans, VLDLR is encoded by the VLDLR gene. Mutations of this gene may lead to a variety of symptoms and diseases, which include type I lissencephaly, cerebellar hypoplasia, and atherosclerosis.
Familial hypercholesterolemia (FH) is a genetic disorder characterized by high cholesterol levels, specifically very high levels of low-density lipoprotein, in the blood and early cardiovascular disease. The most common mutations diminish the number of functional LDL receptors in the liver. Since the underlying body biochemistry is slightly different in individuals with FH, their high cholesterol levels are less responsive to the kinds of cholesterol control methods which are usually more effective in people without FH. Nevertheless, treatment is usually effective.
Hypolipoproteinemia, hypolipidemia, or hypolipidaemia is a form of dyslipidemia that is defined by abnormally lowered levels of any or all lipids and/or lipoproteins in the blood. It occurs through genetic disease, malnutrition, malabsorption, wasting disease, cancer, hyperthyroidism, and liver disease.
Low density lipoprotein receptor-related protein-associated protein 1 also known as LRPAP1 or RAP is a chaperone protein which in humans is encoded by the LRPAP1 gene.
Stormie Dawn Jones was the world's first recipient of a successful simultaneous heart and liver organ transplant. On February 14, 1984, under the direction of Dr. Thomas E. Starzl, Drs. Byers W. Shaw Jr. and Henry T. Bahnson replaced the six-year-old's heart and liver at the Children's Hospital of Pittsburgh in Pittsburgh, Pennsylvania. Stormie had a condition which raised her blood cholesterol to 10 times normal levels. The condition, a severe form of familial hypercholesterolemia, and the resultant high levels of low density lipoprotein that damaged her organs, gave her two heart attacks when she was six years old. The case showed that the liver controls blood cholesterol and that high cholesterol is controllable, and was part of the research on cholesterol and the liver that won Joseph L. Goldstein and Michael S. Brown the Nobel prize in medicine in 1985. Stormie died on November 11, 1990. Her death was related to rejection of the heart transplant she had received in 1984.
Blood lipids are lipids in the blood, either free or bound to other molecules. They are mostly transported in a protein capsule, and the density of the lipids and type of protein determines the fate of the particle and its influence on metabolism. The concentration of blood lipids depends on intake and excretion from the intestine, and uptake and secretion from cells. Hyperlipidemia is the presence of elevated or abnormal levels of lipids and/or lipoproteins in the blood, and is a major risk factor for cardiovascular disease.
Proprotein convertase subtilisin/kexin type 9 (PCSK9) is an enzyme encoded by the PCSK9 gene in humans on chromosome 1. It is the 9th member of the proprotein convertase family of proteins that activate other proteins. Similar genes (orthologs) are found across many species. As with many proteins, PCSK9 is inactive when first synthesized, because a section of peptide chains blocks their activity; proprotein convertases remove that section to activate the enzyme. The PCSK9 gene also contains one of 27 loci associated with increased risk of coronary artery disease.
Low-density lipoprotein receptor adapter protein 1 is a protein that in humans is encoded by the LDLRAP1 gene.
Hypoalphalipoproteinemia is a high-density lipoprotein deficiency, inherited in an autosomal dominant manner.
Lomitapide, sold under the brand name Juxtapid in the US and as Lojuxta in the EU) is a medication used as a lipid-lowering agent for the treatment of familial hypercholesterolemia, developed by Aegerion Pharmaceuticals. It has been tested in clinical trials as single treatment and in combinations with atorvastatin, ezetimibe and fenofibrate.
YWTD repeats are four-stranded beta-propeller repeats found in low-density lipoprotein receptors (LDLR). The six YWTD repeats together fold into a six-bladed beta-propeller. Each blade of the propeller consists of four antiparallel beta-strands; the innermost strand of each blade is labeled 1 and the outermost strand, 4. The sequence repeats are offset with respect to the blades of the propeller, such that any given 40-residue YWTD repeat spans strands 24 of one propeller blade and strand 1 of the subsequent blade. This offset ensures circularization of the propeller because the last strand of the final sequence repeat acts as an innermost strand 1 of the blade that harbors strands 24 from the first sequence repeat. The repeat is found in a variety of proteins that include, vitellogenin receptor from Drosophila melanogaster, low-density lipoprotein (LDL) receptor, preproepidermal growth factor, and nidogen (entactin).
References
- ↑ Braunwald, Eugene; Hauser, Stephen L.; et al. (2001). Harrison's Principles of Internal Medicine . McGraw-hill. pp. 2246–2247. ISBN 978-0-07-007272-5.
- ↑ Homer VM, George PM, du Toit S, Davidson JS, Wilson CJ (July 2005). "Mental retardation and ataxia due to normotriglyceridemic hypobetalipoproteinemia". Ann. Neurol. 58 (1): 160–3. doi:10.1002/ana.20531. PMID 15984016. S2CID 6981284.
