Endothelial dysfunction

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Comparison of healthy vs. dysfunctional vascular endothelium Viruses-13-00029-g001.webp
Comparison of healthy vs. dysfunctional vascular endothelium

In vascular diseases, endothelial dysfunction is a systemic pathological state of the endothelium. The main cause of endothelial dysfunction is impaired bioavailability of nitric oxide, [1]

Contents

In addition to acting as a semipermeable membrane, the endothelium is responsible for maintaining vascular tone and regulating oxidative stress by releasing mediators, such as nitric oxide, prostacyclin and endothelin, and by controlling local angiotensin-II activity. [2] [3]

Dysfunctional endothelium is characterized by vasoconstriction, increased vascular permeability, thrombosis, and inflammation. This pathological state is often associated with elevated levels of biomarkers such as prothrombin time, D-dimer, fibrin degradation products, C-reactive protein (CRP), ferritin, Interleukin 6 (IL-6), and plasma creatinine. The result of this endothelial dysregulation is a cascade of adverse effects, including vasoconstriction, vascular leakage, thrombosis, hyperinflammation, and a disrupted antiviral immune response. These changes contribute to the progression of vascular diseases. [4]

In a healthy state, the endothelium exhibits vasodilation, tightly controlled vascular permeability, and anti-thrombotic and anti-inflammatory properties. This balance ensures the smooth functioning of the vascular system. [4]

Research

Atherosclerosis

Stages of endothelial dysfunction in atherosclerosis of arteries Atherosclerosis timeline - endothelial dysfunction.svg
Stages of endothelial dysfunction in atherosclerosis of arteries

Endothelial dysfunction may be involved in the development of atherosclerosis [5] [6] [7] and may predate vascular pathology. [5] [8] Endothelial dysfunction may also lead to increased adherence of monocytes and macrophages, as well as promoting infiltration of low-density lipoprotein (LDL) in the vessel wall. [9] Oxidized LDL is a hallmark feature of atherosclerosis, [10] by promoting the formation of foam cells, monocyte chemotaxis, and platelet activation, leading to atheromatous plaque instability and ultimately to rupture. [11] Dyslipidemia and hypertension are well known to contribute to endothelial dysfunction, [12] [13] and lowering blood pressure and LDL has been shown to improve endothelial function, particularly when lowered with ACE inhibitors, calcium channel blockers, and statins. [14] Steadily laminar flow with high shear stress in blood vessels protects against atherosclerosis, whereas disturbed flow promotes atherosclerosis. [1]

Nitric oxide

Nitric oxide (NO) suppresses platelet aggregation, inflammation, oxidative stress, vascular smooth muscle cell migration and proliferation, and leukocyte adhesion. [6] A feature of endothelial dysfunction is the inability of arteries and arterioles to dilate fully in response to an appropriate stimulus, such as exogenous nitroglycerine, [5] that stimulates release of vasodilators from the endothelium like NO. Endothelial dysfunction is commonly associated with decreased NO bioavailability, which is due to impaired NO production by the endothelium or inactivation of NO by reactive oxygen species. [10] [15] As a co-factor for nitric oxide synthase, tetrahydrobiopterin (BH4) supplementation has shown beneficial results for the treatment of endothelial dysfunction in animal experiments and clinical trials, although the tendency of BH4 to become oxidized to BH2 remains a problem. [15]

Testing and diagnosis

In the coronary circulation, angiography of coronary artery responses to vasoactive agents may be used to test for endothelial function, and venous occlusion plethysmography and ultrasonography are used to assess endothelial function of peripheral vessels in humans. [5]

A non-invasive method to measure endothelial dysfunction is % Flow-Mediated Dilation (FMD) as measured by Brachial Artery Ultrasound Imaging (BAUI). [16] Current measurements of endothelial function via FMD vary due to technical and physiological factors. Furthermore, a negative correlation between percent flow mediated dilation and baseline artery size is recognised as a fundamental scaling problem, leading to biased estimates of endothelial function. [17]

A non-invasive, FDA-approved device for measuring endothelial function that works by measuring Reactive Hyperemia Index (RHI) is Itamar Medical's EndoPAT. [18] [19] It has shown an 80% sensitivity and 86% specificity to diagnose coronary artery disease when compared against the gold standard, acetylcholine angiogram. [20] This results suggests that this peripheral test reflects the physiology of the coronary endothelium.

Since NO maintains low tone and high compliance of the small arteries at rest, [21] a reduction of age-dependent small artery compliance is a marker for endothelial dysfunction that is associated with both functional and structural changes in the microcirculation. [22] Small artery compliance or stiffness can be assessed simply and at rest and can be distinguished from large artery stiffness by use of pulsewave analysis. [23]

Endothelial dysfunction and stents

Stent implantation has been correlated with impaired endothelial function in several studies. [24] Sirolimus eluting stents were previously used because they showed low rates of in-stent restenosis, but further investigation showed that they often impair endothelial function in humans and worsen conditions. [24] One drug used to inhibit restenosis is iopromide-paclitaxel. [25]

Risk reduction

Treatment of hypertension and hypercholesterolemia may improve endothelial function in people taking statins (HMGCoA-reductase inhibitor), and renin angiotensin system inhibitors, such as ACE inhibitors and angiotensin II receptor antagonists. [26] [27] Calcium channel blockers and selective beta 1 antagonists may also improve endothelial dysfunction. [14] Life style modifications such as smoking cessation have also been shown to improve endothelial function and lower the risk of major cardiovascular events. [28]

See also

Related Research Articles

<span class="mw-page-title-main">Angioplasty</span> Procedure to widen narrow arteries or veins

Angioplasty, also known as balloon angioplasty and percutaneous transluminal angioplasty (PTA), is a minimally invasive endovascular procedure used to widen narrowed or obstructed arteries or veins, typically to treat arterial atherosclerosis.

<span class="mw-page-title-main">Atherosclerosis</span> Form of arteriosclerosis

Atherosclerosis is a pattern of the disease arteriosclerosis, characterized by development of abnormalities called lesions in walls of arteries. These lesions may lead to narrowing of the arterial walls due to buildup of atheromatous plaques. At onset there are usually no symptoms, but if they develop, symptoms generally begin around middle age. In severe cases, it can result in coronary artery disease, stroke, peripheral artery disease, or kidney disorders, depending on which body part(s) the affected arteries are located in the body.

<span class="mw-page-title-main">Endothelium</span> Layer of cells that lining inner surface of blood vessels

The endothelium is a single layer of squamous endothelial cells that line the interior surface of blood vessels and lymphatic vessels. The endothelium forms an interface between circulating blood or lymph in the lumen and the rest of the vessel wall. Endothelial cells form the barrier between vessels and tissue and control the flow of substances and fluid into and out of a tissue.

<span class="mw-page-title-main">Restenosis</span> Recurrence of stenosis, a narrowing of a blood vessel

Restenosis is the recurrence of stenosis, a narrowing of a blood vessel, leading to restricted blood flow. Restenosis usually pertains to an artery or other large blood vessel that has become narrowed, received treatment to clear the blockage, and subsequently become re-narrowed. This is usually restenosis of an artery, or other blood vessel, or possibly a vessel within an organ.

<span class="mw-page-title-main">Coronary thrombosis</span> Medical condition

Coronary thrombosis is defined as the formation of a blood clot inside a blood vessel of the heart. This blood clot may then restrict blood flow within the heart, leading to heart tissue damage, or a myocardial infarction, also known as a heart attack.

<span class="mw-page-title-main">Haemodynamic response</span>

In haemodynamics, the body must respond to physical activities, external temperature, and other factors by homeostatically adjusting its blood flow to deliver nutrients such as oxygen and glucose to stressed tissues and allow them to function. Haemodynamic response (HR) allows the rapid delivery of blood to active neuronal tissues. The brain consumes large amounts of energy but does not have a reservoir of stored energy substrates. Since higher processes in the brain occur almost constantly, cerebral blood flow is essential for the maintenance of neurons, astrocytes, and other cells of the brain. This coupling between neuronal activity and blood flow is also referred to as neurovascular coupling.

<span class="mw-page-title-main">Tetrahydrobiopterin</span> Chemical compound

Tetrahydrobiopterin (BH4, THB), also known as sapropterin (INN), is a cofactor of the three aromatic amino acid hydroxylase enzymes, used in the degradation of amino acid phenylalanine and in the biosynthesis of the neurotransmitters serotonin (5-hydroxytryptamine, 5-HT), melatonin, dopamine, norepinephrine (noradrenaline), epinephrine (adrenaline), and is a cofactor for the production of nitric oxide (NO) by the nitric oxide synthases. Chemically, its structure is that of a (dihydropteridine reductase) reduced pteridine derivative (quinonoid dihydrobiopterin).

Vasospasm refers to a condition in which an arterial spasm leads to vasoconstriction. This can lead to tissue ischemia and tissue death (necrosis). Cerebral vasospasm may arise in the context of subarachnoid hemorrhage. Symptomatic vasospasm or delayed cerebral ischemia is a major contributor to post-operative stroke and death especially after aneurysmal subarachnoid hemorrhage. Vasospasm typically appears 4 to 10 days after subarachnoid hemorrhage.

<span class="mw-page-title-main">Endothelin</span>

Endothelins are peptides with receptors and effects in many body organs. Endothelin constricts blood vessels and raises blood pressure. The endothelins are normally kept in balance by other mechanisms, but when overexpressed, they contribute to high blood pressure (hypertension), heart disease, and potentially other diseases.

<span class="mw-page-title-main">Variant angina</span> Medical condition

Variant angina, also known as Prinzmetal angina,vasospastic angina, angina inversa, coronary vessel spasm, or coronary artery vasospasm, is a syndrome typically consisting of angina. Variant angina differs from stable angina in that it commonly occurs in individuals who are at rest or even asleep, whereas stable angina is generally triggered by exertion or intense exercise. Variant angina is caused by vasospasm, a narrowing of the coronary arteries due to contraction of the heart's smooth muscle tissue in the vessel walls. In comparison, stable angina is caused by the permanent occlusion of these vessels by atherosclerosis, which is the buildup of fatty plaque and hardening of the arteries.

In blood vessels Endothelium-Derived Hyperpolarizing Factor or EDHF is proposed to be a substance and/or electrical signal that is generated or synthesized in and released from the endothelium; its action is to hyperpolarize vascular smooth muscle cells, causing these cells to relax, thus allowing the blood vessel to expand in diameter.

The epoxyeicosatrienoic acids or EETs are signaling molecules formed within various types of cells by the metabolism of arachidonic acid by a specific subset of cytochrome P450 enzymes termed cytochrome P450 epoxygenases. These nonclassic eicosanoids are generally short-lived, being rapidly converted from epoxides to less active or inactive dihydroxy-eicosatrienoic acids (diHETrEs) by a widely distributed cellular enzyme, soluble epoxide hydrolase (sEH), also termed epoxide hydrolase 2. The EETs consequently function as transiently acting, short-range hormones; that is, they work locally to regulate the function of the cells that produce them or of nearby cells. The EETs have been most studied in animal models where they show the ability to lower blood pressure possibly by a) stimulating arterial vasorelaxation and b) inhibiting the kidney's retention of salts and water to decrease intravascular blood volume. In these models, EETs prevent arterial occlusive diseases such as heart attacks and brain strokes not only by their anti-hypertension action but possibly also by their anti-inflammatory effects on blood vessels, their inhibition of platelet activation and thereby blood clotting, and/or their promotion of pro-fibrinolytic removal of blood clots. With respect to their effects on the heart, the EETs are often termed cardio-protective. Beyond these cardiovascular actions that may prevent various cardiovascular diseases, studies have implicated the EETs in the pathological growth of certain types of cancer and in the physiological and possibly pathological perception of neuropathic pain. While studies to date imply that the EETs, EET-forming epoxygenases, and EET-inactivating sEH can be manipulated to control a wide range of human diseases, clinical studies have yet to prove this. Determination of the role of the EETS in human diseases is made particularly difficult because of the large number of EET-forming epoxygenases, large number of epoxygenase substrates other than arachidonic acid, and the large number of activities, some of which may be pathological or injurious, that the EETs possess.

<span class="mw-page-title-main">Drug-eluting stent</span> Medical implant

A drug-eluting stent (DES) is a tube made of a mesh-like material used to treat narrowed arteries in medical procedures both mechanically and pharmacologically. DES is inserted into a narrowed artery using a balloon. Once the balloon inside the stent is inflated, the stent expands, pushing against the artery wall, keeping the artery open, thereby improving blood flow. The mesh design allows cells to grow through and around it, securing it in place.

Coronary vasospasm refers to when a coronary artery suddenly undergoes either complete or sub-total temporary occlusion.

<span class="mw-page-title-main">Endothelial NOS</span> Protein and coding gene in humans

Endothelial NOS (eNOS), also known as nitric oxide synthase 3 (NOS3) or constitutive NOS (cNOS), is an enzyme that in humans is encoded by the NOS3 gene located in the 7q35-7q36 region of chromosome 7. This enzyme is one of three isoforms that synthesize nitric oxide (NO), a small gaseous and lipophilic molecule that participates in several biological processes. The other isoforms include neuronal nitric oxide synthase (nNOS), which is constitutively expressed in specific neurons of the brain and inducible nitric oxide synthase (iNOS), whose expression is typically induced in inflammatory diseases. eNOS is primarily responsible for the generation of NO in the vascular endothelium, a monolayer of flat cells lining the interior surface of blood vessels, at the interface between circulating blood in the lumen and the remainder of the vessel wall. NO produced by eNOS in the vascular endothelium plays crucial roles in regulating vascular tone, cellular proliferation, leukocyte adhesion, and platelet aggregation. Therefore, a functional eNOS is essential for a healthy cardiovascular system.

The chronic endothelial injury hypothesis is one of two major mechanisms postulated to explain the underlying cause of atherosclerosis and coronary heart disease (CHD), the other being the lipid hypothesis. Although an ongoing debate involving connection between dietary lipids and CHD sometimes portrays the two hypotheses as being opposed, they are in no way mutually exclusive. Moreover, since the discovery of the role of LDL cholesterol (LDL-C) in the pathogenesis of atherosclerosis, the two hypotheses have become tightly linked by a number of molecular and cellular processes.

Endothelial activation is a proinflammatory and procoagulant state of the endothelial cells lining the lumen of blood vessels. It is most characterized by an increase in interactions with white blood cells (leukocytes), and it is associated with the early states of atherosclerosis and sepsis, among others. It is also implicated in the formation of deep vein thrombosis. As a result of activation, enthothelium releases Weibel–Palade bodies.

A dual therapy stent is a coronary artery stent that combines the technology of an antibody-coated stent and a drug-eluting stent. Currently, second-generation drug-eluting stents require long-term use of dual-antiplatelet therapy, which increases the risk of major bleeding occurrences in patients. Compared to drug-eluting stents, dual therapy stents have improved vessel regeneration and cell proliferation capabilities. As a result, dual therapy stents were developed to reduce the long-term need for dual-antiplatelet therapy.

Flow-mediated dilation (FMD) refers to dilation (widening) of an artery when blood flow increases in that artery. The primary cause of FMD is release of nitric oxide by endothelial cells.

In medicine, vein graft failure (VGF) is a condition in which vein grafts, which are used as alternative conduits in bypass surgeries, get occluded.

References

  1. 1 2 Marchio P, Guerra-Ojeda S, Mauricio MD (2019). "Targeting Early Atherosclerosis: A Focus on Oxidative Stress and Inflammation". Oxidative Medicine and Cellular Longevity . 2019: 8563845. doi: 10.1155/2019/8563845 . PMC   6636482 . PMID   31354915.
  2. ↑ Sitia, S.; Tomasoni, L.; Atzeni, F.; Ambrosio, G.; Cordiano, C.; Catapano, A.; Tramontana, S.; Perticone, F.; Naccarato, P. (2010). "From endothelial dysfunction to atherosclerosis". Autoimmunity Reviews. 9 (12): 830–834. doi:10.1016/j.autrev.2010.07.016. PMID   20678595.
  3. ↑ Flammer AJ, Anderson T, Celermajer DS, Creager MA, Deanfield J, Ganz P, Hamburg NM, Lüscher TF, Shechter M, Taddei S, Vita JA, Lerman A (Aug 2012). "The assessment of endothelial function: from research into clinical practice". Circulation. 126 (6): 753–67. doi:10.1161/circulationaha.112.093245. PMC   3427943 . PMID   22869857.
  4. 1 2 Bernard, Isabelle; Limonta, Daniel; Mahal, Lara K.; Hobman, Tom C. (January 2021). "Endothelium Infection and Dysregulation by SARS-CoV-2: Evidence and Caveats in COVID-19". Viruses. 13 (1): 29. doi: 10.3390/v13010029 . ISSN   1999-4915. PMC   7823949 . PMID   33375371.
  5. 1 2 3 4 Maruhashi, T; Kihara, Y; Higashi, Y (2018). "Assessment of endothelium-independent vasodilation: From methodology to clinical perspectives". Journal of Hypertension. 36 (7): 1460–1467. doi:10.1097/HJH.0000000000001750. PMID   29664811. S2CID   4948849.
  6. 1 2 Eren E, Yilmaz N, Aydin O (2013). "Functionally defective high-density lipoprotein and paraoxonase: a couple for endothelial dysfunction in atherosclerosis". Cholesterol. 2013: 792090. doi: 10.1155/2013/792090 . PMC   3814057 . PMID   24222847.
  7. ↑ Botts SR, Fish JE, Howe KL (December 2021). "Dysfunctional Vascular Endothelium as a Driver of Atherosclerosis: Emerging Insights Into Pathogenesis and Treatment". Frontiers in Pharmacology. 12: 787541. doi: 10.3389/fphar.2021.787541 . PMC   8727904 . PMID   35002720.
  8. ↑ Münzel T, Sinning C, Post F, Warnholtz A, Schulz E (2008). "Pathophysiology, diagnosis and prognostic implications of endothelial dysfunction". Annals of Medicine. 40 (3): 180–96. doi: 10.1080/07853890701854702 . PMID   18382884. S2CID   18542183.
  9. ↑ Poredos, P. (2001). "Endothelial dysfunction in the pathogenesis of atherosclerosis". Clinical and Applied Thrombosis/Hemostasis. 7 (4): 276–280. doi:10.1177/107602960100700404. ISSN   1076-0296. PMID   11697708. S2CID   71334997.
  10. 1 2 Gradinaru D, Borsa C, Prada GI (2015). "Oxidized LDL and NO synthesis--Biomarkers of endothelial dysfunction and ageing". Mechanisms of Ageing and Development . 151: 101–113. doi: 10.1016/j.mad.2015.03.003 . PMID   25804383.
  11. ↑ Jiang M, Zhou Y, Ge J (2022). "Mechanisms of Oxidized LDL-Mediated Endothelial Dysfunction and Its Consequences for the Development of Atherosclerosis". Frontiers in Cardiovascular Medicine . 9: 925923. doi: 10.3389/fcvm.2022.925923 . PMC   9199460 . PMID   35722128.
  12. ↑ Le Master, Elizabeth; Levitan, Irena (2019-01-22). "Endothelial stiffening in dyslipidemia". Aging. 11 (2): 299–300. doi:10.18632/aging.101778. ISSN   1945-4589. PMC   6366977 . PMID   30674709.
  13. ↑ Konukoglu, Dildar; Uzun, Hafize (2017). "Endothelial Dysfunction and Hypertension". Hypertension: From basic research to clinical practice. Advances in Experimental Medicine and Biology. Vol. 956. pp. 511–540. doi:10.1007/5584_2016_90. ISBN   978-3-319-44250-1. ISSN   0065-2598. PMID   28035582.
  14. 1 2 Ghiadoni, Lorenzo; Taddei, Stefano; Virdis, Agostino (2012). "Hypertension and endothelial dysfunction: therapeutic approach". Current Vascular Pharmacology. 10 (1): 42–60. doi:10.2174/157016112798829823. ISSN   1875-6212. PMID   22112351.
  15. 1 2 Yuyun MF, Ng LL, Ng GA (2018). "Endothelial dysfunction, endothelial nitric oxide bioavailability, tetrahydrobiopterin, and 5-methyltetrahydrofolate in cardiovascular disease. Where are we with therapy?". Microvascular Research . 119: 7–12. doi:10.1016/j.mvr.2018.03.012. PMID   29596860.
  16. ↑ Peretz, Alon; Daniel F Leotta; Jeffrey H Sullivan; Carol A Trenga; Fiona N Sands; Mary R Aulet (2007). "Flow mediated dilation of the brachial artery: an investigation of methods requiring further standardization". BMC Cardiovascular Disorders. 7 (11): 11. doi: 10.1186/1471-2261-7-11 . PMC   1847451 . PMID   17376239.
  17. ↑ Thijssen DH, Black MA, Pyke KE, Padilla J, Atkinson G, Harris RA, Parker B, Widlansky ME, Tschakovsky ME, Green DJ (Jan 2011). "Assessment of flow-mediated dilation in humans: a methodological and physiological guideline". Am J Physiol Heart Circ Physiol. 300 (1): H2–12. doi:10.1152/ajpheart.00471.2010. PMC   3023245 . PMID   20952670.
  18. ↑ Kuvin JT, Mammen A, Mooney P, Alsheikh-Ali AA, Karas RH (Feb 2007). "Assessment of peripheral vascular endothelial function in the ambulatory setting". Vasc. Med. 12 (1): 13–6. doi: 10.1177/1358863x06076227 . PMID   17451088.
  19. ↑ Axtell AL, Gomari FA, Cooke JP (October 2010). "Assessing endothelial vasodilator function with the Endo-PAT 2000". Journal of Visualized Experiments (44). doi:10.3791/2167. PMC   3143035 . PMID   20972417.
  20. ↑ Bonetti PO, Pumper GM, Higano ST, Holmes DR Jr, Kuvin JT, Lerman A (Dec 2004). "Noninvasive identification of patients with early coronary atherosclerosis by assessment of digital reactive hyperemia". J Am Coll Cardiol. 44 (11): 2137–41. doi: 10.1016/j.jacc.2004.08.062 . PMID   15582310.
  21. ↑ Gilani M, Kaiser DR, Bratteli CW, Alinder C, Rajala Bank AJ, Cohn JN (2007). "Role of nitric oxide deficiency and its detection as a risk factor in pre-hypertension". JASH. 1 (1): 45–56. doi:10.1016/j.jash.2006.11.002. PMID   20409832.
  22. ↑ Duprez DA, Jacobs DR, Lutsey PL, Bluemke FA, Brumback LC, Polak JF, Peralta CA, Greenland P, Kronmal RA (2011). "Association of small artery elasticity with incident cardiovascular disease in older adults: the multiethnic study of atherosclerosis". Am J Epidemiol. 174 (5): 528–36. doi:10.1093/aje/kwr120. PMC   3202150 . PMID   21709134.
  23. ↑ Cohn JN, Duprez DA, Finkelstein SM (2009). "Comprehensive noninvasive arterial vascular evaluation". Future Cardiology. 5 (6): 573–9. doi:10.2217/fca.09.44. PMID   19886784.
  24. 1 2 Bedair, T. M; Elnaggar, M. A; Joung, Y. K; Han, D. K (2017). "Recent advances to accelerate re-endothelialization for vascular stents". Journal of Tissue Engineering. 8: 2041731417731546. doi:10.1177/2041731417731546. PMC   5624345 . PMID   28989698.
  25. ↑ Unverdorben, Martin; Vallbracht, Christian; Cremers, Bodo; Heuer, Hubertus; Hengstenberg, Christian; Maikowski, Christian; Werner, Gerald S.; Antoni, Diethmar; Kleber, Franz X. (2009-06-16). "Paclitaxel-coated balloon catheter versus paclitaxel-coated stent for the treatment of coronary in-stent restenosis". Circulation. 119 (23): 2986–2994. doi: 10.1161/circulationaha.108.839282 . ISSN   0009-7322. PMID   19487593.
  26. ↑ Ruilope LM, Redón J, Schmieder R (2007). "Cardiovascular risk reduction by reversing endothelial dysfunction: ARBs, ACE inhibitors, or both? Expectations from the ONTARGET Trial Programme". Vascular Health and Risk Management. 3 (1): 1–9. PMC   1994043 . PMID   17583170.
  27. ↑ Briasoulis A, Tousoulis D, Androulakis ES, Papageorgiou N, Latsios G, Stefanadis C (Apr 2012). "Endothelial dysfunction and atherosclerosis: focus on novel therapeutic approaches". Recent Pat Cardiovasc Drug Discov. 7 (1): 21–32. doi:10.2174/157489012799362386. PMID   22280336.
  28. ↑ Messner, Barbara; Bernhard, David (2014). "Smoking and cardiovascular disease: mechanisms of endothelial dysfunction and early atherogenesis". Arteriosclerosis, Thrombosis, and Vascular Biology. 34 (3): 509–515. doi: 10.1161/ATVBAHA.113.300156 . ISSN   1524-4636. PMID   24554606.
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