Lipoprotein(a)
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Lipoprotein(a) is a
low-density lipoprotein Low-density lipoprotein (LDL) is one of the five major groups of lipoprotein that transport all fat molecules around the body in extracellular water. These groups, from least dense to most dense, are chylomicrons (aka ULDL by the overall densi ...
variant containing a protein called apolipoprotein(a). Genetic and
epidemiological studies Epidemiology is the study and analysis of the distribution (who, when, and where), patterns and determinants of health and disease conditions in a defined population. It is a cornerstone of public health, and shapes policy decisions and evid ...
have identified lipoprotein(a) as a risk factor for
atherosclerosis Atherosclerosis is a pattern of the disease arteriosclerosis in which the wall of the artery develops abnormalities, called lesions. These lesions may lead to narrowing due to the buildup of atheromatous plaque. At onset there are usually no s ...
and related diseases, such as
coronary heart disease Coronary artery disease (CAD), also called coronary heart disease (CHD), ischemic heart disease (IHD), myocardial ischemia, or simply heart disease, involves the reduction of blood flow to the heart muscle due to build-up of atherosclerotic pl ...
and
stroke A stroke is a disease, medical condition in which poor cerebral circulation, blood flow to the brain causes cell death. There are two main types of stroke: brain ischemia, ischemic, due to lack of blood flow, and intracranial hemorrhage, hemorr ...
. Lipoprotein(a) was discovered in 1963 by
Kåre Berg Kåre Ingmar Berg, MD (1 March 1932 – 24 January 2009) was a Norwegian professor in medical genetics, physician-in-chief and well-cited researcher. Education and positions Kåre Berg was born in Hammerfest. He graduated as MD in 1957 and dr.m ...
. The human
gene In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a b ...
encoding apolipoprotein(a) was successfully cloned in 1987.


Structure

Lipoprotein(a)
p(a) P, or p, is the sixteenth letter of the Latin alphabet, used in the modern English alphabet, the alphabets of other western European languages and others worldwide. Its name in English is ''pee'' (pronounced ), plural ''pees''. History The ...
consists of an LDL-like particle and the specific apolipoprotein(a), which is bound covalently to the
apoB Apolipoprotein B (ApoB) is a protein that in humans is encoded by the gene. Function Apolipoprotein B is the primary apolipoprotein of chylomicrons, VLDL, Lp(a), IDL, and LDL particles (LDL—commonly known as "bad cholesterol" when in refer ...
contained in the outer shell of the particle. Lp(a) plasma concentrations are highly heritable and mainly controlled by the LPA gene located on
chromosome 6 Chromosome 6 is one of the 23 pairs of chromosomes in humans. People normally have two copies of this chromosome. Chromosome 6 spans more than 170 million base pairs (the building material of DNA) and represents between 5.5 and 6% of the total D ...
q26-27. Apo(a) proteins vary in size due to a size polymorphism VNTR.html"_;"title="variable_number_tandem_repeat.html"_;"title="IV-2_variable_number_tandem_repeat">VNTR">variable_number_tandem_repeat.html"_;"title="IV-2_variable_number_tandem_repeat">VNTR_which_is_caused_by_a_variable_number_of_kringle_domain.html" "title="ariable_number_tandem_repeat">VNTR.html" ;"title="variable_number_tandem_repeat.html" ;"title="IV-2 variable number tandem repeat">VNTR">variable_number_tandem_repeat.html" ;"title="IV-2 variable number tandem repeat">VNTR which is caused by a variable number of kringle domain">kringle Kringle (, ) is a Northern European pastry, a variety of pretzel. Pretzels were introduced by Roman Catholic monks in the 13th century in Denmark, and from there they spread throughout Scandinavia and evolved into several kinds of sweet, salty ...
IV repeats in the LPA gene. This size variation at the gene level is expressed on the protein level as well, resulting in apo(a) proteins with 10 to more than 50 kringle IV repeats (each of the variable kringle IV consists of 114 amino acids). These variable apo(a) sizes are known as "apo(a) protein isoform, isoforms". There is a general inverse correlation between the size of the apo(a) isoform and the Lp(a) plasma concentration. One theory explaining this correlation involves different rates of protein synthesis. Specifically, the larger the isoform, the more apo(a) precursor protein accumulates
intracellular This glossary of biology terms is a list of definitions of fundamental terms and concepts used in biology, the study of life and of living organisms. It is intended as introductory material for novices; for more specific and technical definitions ...
ly in the
endoplasmic reticulum The endoplasmic reticulum (ER) is, in essence, the transportation system of the eukaryotic cell, and has many other important functions such as protein folding. It is a type of organelle made up of two subunits – rough endoplasmic reticulum ...
. Lp(a) is not fully synthesised until the precursor protein is released from the cell, so the slower rate of production for the larger isoforms limits the plasma concentration.


Populations

Lp(a) concentrations can vary by more than one thousand between individuals, from <0.2 to >200 mg/dL. This range of concentrations is observed in all populations studied by scientists so far. The mean and median concentrations differ among world populations. Most prominently, there is a two- to threefold higher mean Lp(a) plasma concentration in populations of African descent compared to Asian, Oceanic, or European populations. The general inverse correlation between apo(a) isoform size and Lp(a) plasma concentration is observed in all populations. However, it was also discovered that mean Lp(a) associated with certain apo(a) isoforms varies between populations. In addition to size effects, mutations in the LPA promoter may also lead to a decreased apo(a) production.


Function and pathology

Lp(a) is assembled at the
hepatocyte A hepatocyte is a cell of the main parenchymal tissue of the liver. Hepatocytes make up 80% of the liver's mass. These cells are involved in: * Protein synthesis * Protein storage * Transformation of carbohydrates * Synthesis of cholesterol, ...
cell membrane surface, which is similar to typical LDL particles. However, there are other possible locations of assembly. The particles mainly exist in plasma. Lp(a) contributes to the process of
atherogenesis Atherosclerosis is a pattern of the disease arteriosclerosis in which the wall of the artery develops abnormalities, called lesions. These lesions may lead to narrowing due to the buildup of atheromatous plaque. At onset there are usually no ...
. The structure of apolipoprotein(a) is similar to
plasminogen Plasmin is an important enzyme () present in blood that degrades many blood plasma proteins, including fibrin clots. The degradation of fibrin is termed fibrinolysis. In humans, the plasmin protein (in the zymogen form of plasminogen) is enco ...
and tPA (
tissue plasminogen activator Tissue plasminogen activator (abbreviated tPA or PLAT) is a protein involved in the breakdown of blood clots. It is a serine protease () found on endothelial cells, the cells that line the blood vessels. As an enzyme, it catalyzes the conversion ...
) and it competes with plasminogen for its binding site, leading to reduced
fibrinolysis Fibrinolysis is a process that prevents blood clots from growing and becoming problematic. Primary fibrinolysis is a normal body process, while secondary fibrinolysis is the breakdown of clots due to a medicine, a medical disorder, or some other ...
. Also, because Lp(a) stimulates secretion of
PAI-1 Plasminogen activator inhibitor-1 (PAI-1) also known as endothelial plasminogen activator inhibitor or serpin E1 is a protein that in humans is encoded by the ''SERPINE1'' gene. Elevated PAI-1 is a risk factor for thrombosis and atherosclerosis P ...
, it leads to thrombogenesis. It also may enhance coagulation by inhibiting the function of tissue factor pathway inhibitor. Moreover, Lp(a) carries
atherosclerosis Atherosclerosis is a pattern of the disease arteriosclerosis in which the wall of the artery develops abnormalities, called lesions. These lesions may lead to narrowing due to the buildup of atheromatous plaque. At onset there are usually no s ...
-causing cholesterol and binds atherogenic pro-inflammatory oxidised phospholipids as a preferential carrier of oxidised phospholipids in human plasma, which attracts inflammatory cells to vessel walls and leads to smooth muscle cell proliferation. Moreover, Lp(a) also is hypothesised to be involved in wound healing and tissue repair by interacting with components of the vascular wall and
extracellular matrix In biology, the extracellular matrix (ECM), also called intercellular matrix, is a three-dimensional network consisting of extracellular macromolecules and minerals, such as collagen, enzymes, glycoproteins and hydroxyapatite that provide s ...
. Apo(a), a distinct feature of the Lp(a) particle, binds to immobilized fibronectin and endows Lp(a) with the serine-proteinase-type proteolytic activity. Nonetheless, individuals without Lp(a) or with very low Lp(a) levels seem to be healthy. Thus, plasma Lp(a) is not vital, at least under normal environmental conditions. Since apo(a)/Lp(a) appeared rather recently in mammalian evolution – only
old world monkeys Old World monkey is the common English name for a family of primates known taxonomically as the Cercopithecidae (). Twenty-four genera and 138 species are recognized, making it the largest primate family. Old World monkey genera include babo ...
and humans have been shown to harbour Lp(a) – its function might not be vital, but just evolutionarily advantageous under certain environmental conditions, e.g. in case of exposure to certain infectious diseases. Another possibility, suggested by
Linus Pauling Linus Carl Pauling (; February 28, 1901August 19, 1994) was an American chemist, biochemist, chemical engineer, peace activist, author, and educator. He published more than 1,200 papers and books, of which about 850 dealt with scientific topi ...
, is that Lp(a) is a primate adaptation to
L-gulonolactone oxidase L-Gulonolactone oxidase ( ECbr>1.1.3.8 is an enzyme that produces vitamin C, but is non-functional in Haplorrhini (including humans), in some bats, and in guinea pigs. It catalyzes the reaction of L-gulono-1,4-lactone with oxygen to form L ...
(GULO) deficiency, found only in certain lines of mammals. GULO is required for converting
glucose Glucose is a simple sugar with the molecular formula . Glucose is overall the most abundant monosaccharide, a subcategory of carbohydrates. Glucose is mainly made by plants and most algae during photosynthesis from water and carbon dioxide, u ...
to
ascorbic acid Vitamin C (also known as ascorbic acid and ascorbate) is a water-soluble vitamin found in citrus and other fruits and vegetables, also sold as a dietary supplement and as a topical 'serum' ingredient to treat melasma (dark pigment spots) ...
(vitamin C), which is needed to repair arteries; following the loss of GULO, those primates who adopted diets less abundant in vitamin C may have used Lp(a) as an ascorbic-acid surrogate to repair arterial walls.


Catabolism and clearance

The half-life of Lp(a) in circulation is approximately three to four days. The mechanism and sites of Lp(a) catabolism are largely unknown. Uptake via the LDL receptor is not a major pathway of Lp(a) metabolism. The kidney has been identified as playing a role in Lp(a) clearance from plasma.


Disease

High Lp(a) in blood correlates with
coronary heart disease Coronary artery disease (CAD), also called coronary heart disease (CHD), ischemic heart disease (IHD), myocardial ischemia, or simply heart disease, involves the reduction of blood flow to the heart muscle due to build-up of atherosclerotic pl ...
(CHD),
cardiovascular disease Cardiovascular disease (CVD) is a class of diseases that involve the heart or blood vessels. CVD includes coronary artery diseases (CAD) such as angina and myocardial infarction (commonly known as a heart attack). Other CVDs include stroke, hea ...
(CVD),
atherosclerosis Atherosclerosis is a pattern of the disease arteriosclerosis in which the wall of the artery develops abnormalities, called lesions. These lesions may lead to narrowing due to the buildup of atheromatous plaque. At onset there are usually no s ...
,
thrombosis Thrombosis (from Ancient Greek "clotting") is the formation of a blood clot inside a blood vessel, obstructing the flow of blood through the circulatory system. When a blood vessel (a vein or an artery) is injured, the body uses platelets (th ...
, and stroke. However, the association between Lp(a) levels and stroke is not as strong as that between Lp(a) and cardiovascular disease. Lp(a) concentrations may be affected by disease states (for example kidney failure), but are only slightly affected by diet, exercise, and other environmental factors. Most commonly prescribed lipid-reducing drugs have little or no effect on Lp(a) concentration. Results using
statin Statins, also known as HMG-CoA reductase inhibitors, are a class of lipid-lowering medications that reduce illness and mortality in those who are at high risk of cardiovascular disease. They are the most common cholesterol-lowering drugs. Low ...
medications have been mixed in most trials, although a meta-analysis published in 2012 suggests that
atorvastatin Atorvastatin is a statin medication used to prevent cardiovascular disease in those at high risk and to treat abnormal lipid levels. For the prevention of cardiovascular disease, statins are a first-line treatment. It is taken by mouth. Common ...
may be of benefit.
Niacin Niacin, also known as nicotinic acid, is an organic compound and a form of vitamin B3, an essential human nutrient. It can be manufactured by plants and animals from the amino acid tryptophan. Niacin is obtained in the diet from a variet ...
(Vitamin B3) has been shown to reduce the levels of Lp(a) in individuals with high levels of low-molecular weight Lp(a). High Lp(a) correlates with early atherosclerosis independently of other cardiac risk factors, including LDL. In patients with advanced cardiovascular disease, Lp(a) indicates a coagulant risk of plaque thrombosis. Apo(a) contains domains that are very similar to plasminogen (PLG). Lp(a) accumulates in the vessel wall and inhibits the binding of PLG to the cell surface, reducing plasmin generation, which increases clotting. This inhibition of PLG by Lp(a) also promotes the proliferation of
smooth muscle Smooth muscle is an involuntary non- striated muscle, so-called because it has no sarcomeres and therefore no striations (''bands'' or ''stripes''). It is divided into two subgroups, single-unit and multiunit smooth muscle. Within single-unit ...
cells. These unique features of Lp(a) suggest that Lp(a) causes generation of clots and atherosclerosis. In one homogeneous tribal population of Tanzania, vegetarians have higher levels of Lp(a) than fish eaters, raising the possibility that pharmacologic amounts of fish oil supplements may help lower the levels of Lp(a). Some studies have shown that regular consumption of moderate amounts of alcohol leads to a significant decline in plasma levels of Lp(a), while other studies have not.


Diagnostic testing

Numerous studies confirming a strong correlation between elevated Lp(a) and heart disease have led to the consensus that Lp(a) is an important independent predictor of
cardiovascular disease Cardiovascular disease (CVD) is a class of diseases that involve the heart or blood vessels. CVD includes coronary artery diseases (CAD) such as angina and myocardial infarction (commonly known as a heart attack). Other CVDs include stroke, hea ...
. Animal studies have shown that Lp(a) may directly contribute to atherosclerotic damage by increasing plaque size, inflammation, instability, and smooth muscle cell growth. Genetic data also support the theory that Lp(a) causes cardiovascular disease. The European Atherosclerosis Society currently recommends that patients with a moderate or high risk of cardiovascular disease should have their Lp(a) levels checked. Any patient with one of the following risk factors should be screened: * premature cardiovascular disease * familial hypercholesterolaemia * family history of premature cardiovascular disease * family history of elevated Lp(a) * recurrent cardiovascular disease despite statin treatment * ≥3% ten-year risk of fatal cardiovascular disease according to the European guidelines * ≥10% ten-year risk of fatal and/or non-fatal cardiovascular disease according to the U.S. guidelines If the level is elevated, treatment should be initiated to bring the level below 50 mg/dL. In addition, the patient's other cardiovascular risk factors (including LDL levels) should be managed optimally. Apart from the total Lp(a) plasma concentration, the apo(a) isoform might be an important risk parameter as well. Prior studies of the relationship between Lp(a) and ethnicity have shown inconsistent results. Lp(a) levels seem to differ in different populations. For example, in some African populations, Lp(a) levels are higher on average than in other groups, so that using a risk threshold of 30 mg/dl could classify over 50% of the individuals as higher risk. Some part of this complexity may be related to the different genetic factors involved in determining Lp(a) levels. One recent study showed that in different ethnic groups, different genetic alterations were associated with increased Lp(a) levels. More recent data suggest that prior studies were underpowered. The Atherosclerosis Risk in Communities (ARIC) Study followed 3467 African Americans and 9851 whites for 20 years. The researchers found that an elevated Lp(a) conferred the same risk in each group. African Americans had roughly three times the level of Lp(a), however, and Lp(a) also predicted an increased risk of stroke. Approximate levels of risk are indicated by the results below, although at present there are a variety of different methods by which to measure Lp(a). A standardized international reference material has been developed and is accepted by the
WHO Expert Committee on Biological Standardization WHO Expert Committee on Biological Standardization is a functioning body of World Health Organization. The Expert Committee has been meeting annually since 1947. Reports The Committee reports are published as WHO Technical Report Series. All the re ...
and the International Federation of Clinical Chemistry and Laboratory Medicine. Although further standardization is still needed, development of a reference material is an importance step toward standardizing results. Lipoprotein(a) - Lp(a) : Desirable: <14 mg/dL (<35 nmol/L) : Borderline risk: 14–30 mg/dL (35–75 nmol/L) : High risk: 31–50 mg/dL (75–125 nmol/L) : Very high risk: >50 mg/dL (>125 nmol/L) Lp(a) appears with different isoforms (per kringle repeats) of apolipoprotein; 40% of the variation in Lp(a) levels when measured in mg/dl can be attributed to different isoforms. Lighter Lp(a) are also associated with disease. Thus, a test with simple quantitative results may not provide a complete assessment of risk.


Treatment

The current simplest treatment for elevated Lp(a) is to take 1–3 grams of
niacin Niacin, also known as nicotinic acid, is an organic compound and a form of vitamin B3, an essential human nutrient. It can be manufactured by plants and animals from the amino acid tryptophan. Niacin is obtained in the diet from a variet ...
daily, typically in an extended-release form. Niacin therapy may reduce Lp(a) levels by 20–30%. Aspirin may be beneficial, but it has only been tested in patients who carry the apolipoprotein(a) gene minor allele variant, (rs3798220). A meta-analysis suggested that atorvastatin also may lower Lp(a) levels. In severe cases, such as familial hypercholesterolemia or treatment-resistant hypercholesterolemia, lipid apheresis may dramatically reduce Lp(a). The goal of the treatment is to reduce levels to below 50 mg/dL. Other medications that are in various stages of development include thyromimetics, cholesterol-ester-transfer protein (CETP inhibitors), anti-sense oligonucleopeptides, and proprotein convertase subtilisin/kexin type 9 (PCSK-9) inhibitors. L-carnitine may also reduce Lp(a) levels. A meta-analysis of six clinical trials confirmed that flaxseed supplementation modestly lowers Lp(a) levels.{{{cite journal , vauthors = Sahebkar A, Katsiki N, Ward N, Reiner Ž , title = Flaxseed supplementation reduces plasma lipoprotein(a) levels: A meta-analysis , journal = Altern Ther Health Med , volume = 27 , issue = 3 , pages = 50–53 , date = May 2021 , pmid = 31634874 Gingko biloba may be a beneficial treatment, but clinical verification does not exist.{{cite journal , vauthors = Rodríguez M, Ringstad L, Schäfer P, Just S, Hofer HW, Malmsten M, Siegel G , title = Reduction of atherosclerotic nanoplaque formation and size by Ginkgo biloba (EGb 761) in cardiovascular high-risk patients , journal = Atherosclerosis , volume = 192 , issue = 2 , pages = 438–44 , date = June 2007 , pmid = 17397850 , doi = 10.1016/j.atherosclerosis.2007.02.021 {{primary source inline, date=January 2021 Coenzyme Q-10 and pine bark extract have been suggested as beneficial, but neither has been proven in clinical trials.{{cite journal , vauthors = Lee YJ, Cho WJ, Kim JK, Lee DC , title = Effects of coenzyme Q10 on arterial stiffness, metabolic parameters, and fatigue in obese subjects: a double-blind randomized controlled study , journal = J Med Food , volume = 14 , issue = 4 , pages = 386–90 , date = April 2011 , pmid = 21370966 , doi = 10.1089/jmf.2010.1202 {{cite journal , vauthors = Drieling RL, Gardner CD, Ma J, Ahn DK, Stafford RS , title = No beneficial effects of pine bark extract on cardiovascular disease risk factors , journal = Arch. Intern. Med. , volume = 170 , issue = 17 , pages = 1541–7 , date = September 2010 , pmid = 20876405 , doi = 10.1001/archinternmed.2010.310 , doi-access = free Testosterone is known to reduce Lp(a) levels.{{cite journal , vauthors = Zmunda JM, Thompson PD, Dickenson R, Bausserman LL , title = Testosterone decreases lipoprotein(a) in men , journal = The American Journal of Cardiology , volume = 77 , issue = 14 , pages = 1244–7 , year = 1996 , pmid = 8651107 , doi = 10.1016/S0002-9149(96)00174-9 Testosterone replacement therapy also appears to be associated with lower Lp(a) levels.{{cite journal , vauthors = Zmunda JM, Thompson PD, Dickenson R, Bausserman LL , title = Testosterone decreases lipoprotein(a) in men , journal = The American Journal of Cardiology , volume = 77 , issue = 14 , pages = 1244–7 , year = 1996 , pmid = 8651107 , doi = 10.1016/S0002-9149(96)00174-9 {{cite journal , vauthors = Parhofer KG , title = Lipoprotein(a): medical treatment options for an elusive molecule , journal = Curr. Pharm. Des. , volume = 17 , issue = 9 , pages = 871–6 , year = 2011 , pmid = 21476974 , doi = 10.2174/138161211795428777 One large study suggested that there was a decreased association between Lp(a) levels and risk.{{fact, date=April 2017 Estrogen as a prevention strategy for heart disease is a current topic of much research and debate. Risks and benefits may need to be considered for each individual. At present, estrogen is not indicated for treatment of elevated Lp(a).{{cite journal , vauthors = Harman SM, Vittinghoff E, Brinton EA, Budoff MJ, Cedars MI, Lobo RA, Merriam GR, Miller VM, Naftolin F, Pal L, Santoro N, Taylor HS, Black DM , title = Timing and duration of menopausal hormone treatment may affect cardiovascular outcomes , journal = Am. J. Med. , volume = 124 , issue = 3 , pages = 199–205 , date = March 2011 , pmid = 21396500 , pmc = 3107840 , doi = 10.1016/j.amjmed.2010.09.021
Raloxifene Raloxifene, sold under the brand name Evista among others, is a medication used to prevent and treat osteoporosis in postmenopausal women and those on glucocorticoids. For osteoporosis it is less preferred than bisphosphonates. It is also used to ...
has not been shown to reduce Lp(a), while
tamoxifen Tamoxifen, sold under the brand name Nolvadex among others, is a selective estrogen receptor modulator used to prevent breast cancer in women and treat breast cancer in women and men. It is also being studied for other types of cancer. It has b ...
has.{{cite journal , vauthors = Sahebkar A, Serban MC, Penson P, Gurban C, Ursoniu S, Toth PP, Jones SR, Lippi G, Kotani K, Kostner K, Rizzo M, Rysz J, Banach M , title = The Effects of Tamoxifen on Plasma Lipoprotein(a) Concentrations: Systematic Review and Meta-Analysis , journal = Drugs , volume = 77 , issue = 11 , pages = 1187–1197 , year = 2017 , pmid = 28573436 , pmc = 5501893 , doi = 10.1007/s40265-017-0767-4 The
American Academy of Pediatrics The American Academy of Pediatrics (AAP) is an American professional association of pediatricians, headquartered in Itasca, Illinois. It maintains its Department of Federal Affairs office in Washington, D.C. Background The Academy was found ...
now recommends that all children between the ages of nine and eleven years old be screened for hyperlipidemia. Lp(a) levels should be considered in particular in children with a family history of early heart disease or high blood cholesterol levels. Unfortunately, there have not been enough studies to determine which therapies might be beneficial.{{cite journal , title = Expert panel on integrated guidelines for cardiovascular health and risk reduction in children and adolescents: summary report , journal = Pediatrics , volume = 128 Suppl 5 , pages = S213–56 , date = December 2011 , pmid = 22084329 , doi = 10.1542/peds.2009-2107C , pmc=4536582, author1 = Expert Panel on Integrated Guidelines for Cardiovascular Health Risk Reduction in Children Adolescents , last2 = National Heart , first2 = Lung


Interactions

Lp(a) has been shown to
interact Advocates for Informed Choice, doing business as, dba interACT or interACT Advocates for Intersex Youth, is a 501(c)(3) nonprofit organization using innovative strategies to advocate for the legal and human rights of children with intersex trai ...
with
calnexin Calnexin (CNX) is 67kDaintegral protein (that appears variously as a 90kDa, 80kDa, or 75kDa band on western blotting depending on the source of the antibody) of the endoplasmic reticulum (ER). It consists of a large (50 kDa) N-terminal calcium- ...
,{{cite journal , vauthors = Bonen DK, Nassir F, Hausman AM, Davidson NO , title = Inhibition of N-linked glycosylation results in retention of intracellular apo in hepatoma cells, although nonglycosylated and immature forms of apolipoprotein are competent to associate with apolipoprotein B-100 in vitro , journal = J. Lipid Res. , volume = 39 , issue = 8 , pages = 1629–40 , date = August 1998 , doi = 10.1016/S0022-2275(20)32192-1 , pmid = 9717723 , doi-access = free {{cite journal , vauthors = Nassir F, Xie Y, Davidson NO , title = Apolipoprotein secretion from hepatoma cells is regulated in a size-dependent manner by alterations in disulfide bond formation , journal = J. Lipid Res. , volume = 44 , issue = 4 , pages = 816–27 , date = April 2003 , pmid = 12562843 , doi = 10.1194/jlr.M200451-JLR200 , doi-access = free
fibronectin Fibronectin is a high- molecular weight (~500-~600 kDa) glycoprotein of the extracellular matrix that binds to membrane-spanning receptor proteins called integrins. Fibronectin also binds to other extracellular matrix proteins such as coll ...
, and
fibrinogen beta chain Fibrinogen beta chain, also known as FGB, is a gene found in humans and most other vertebrates with a similar system of blood coagulation. The protein encoded by this gene is the beta component of fibrinogen, a blood-borne glycoprotein composed ...
.{{cite journal , vauthors = Klose R, Fresser F, Kochl S, Parson W, Kapetanopoulos A, Fruchart-Najib J, Baier G, Utermann G , title = Mapping of a minimal apolipoprotein(a) interaction motif conserved in fibrin(ogen) beta - and gamma -chains , journal = J. Biol. Chem. , volume = 275 , issue = 49 , pages = 38206–12 , date = December 2000 , pmid = 10980194 , doi = 10.1074/jbc.M003640200 , doi-access = free


See also

*
Lipoprotein 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, ...
*
Apolipoprotein Apolipoproteins are proteins that bind lipids (oil-soluble substances such as fats, cholesterol and fat soluble vitamins) to form lipoproteins. They transport lipids in blood, cerebrospinal fluid and lymph. The lipid components of lipoproteins ...
*
Very-low-density lipoprotein Very-low-density lipoprotein (VLDL), density relative to extracellular water, is a type of lipoprotein made by the liver. VLDL is one of the five major groups of lipoproteins (chylomicrons, VLDL, intermediate-density lipoprotein, low-density lipo ...
*
Combined hyperlipidemia Combined hyperlipidemia (or -aemia) is a commonly occurring form of hypercholesterolemia (elevated cholesterol levels) characterised by increased LDL and triglyceride concentrations, often accompanied by decreased HDL. On lipoprotein electropho ...


References

{{Reflist


External links

* {{MeshName, Lipoprotein(a) * {{PDBe-KB2, P08519, Apolipoprotein(a) {{PDB Gallery, geneid=4018 {{Lipoproteins * Apolipoproteins Lipid disorders Cardiology