Troponin T

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Troponin T
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Troponin
Test of Troponin
Cardiac sarcomere structure featuring troponin T Cardiac sarcomere structure.png
Cardiac sarcomere structure featuring troponin T

Troponin T (shortened TnT [1] or TropT) is a part of the troponin complex, which are proteins integral to the contraction of skeletal and heart muscles. They are expressed in skeletal and cardiac myocytes. Troponin T binds to tropomyosin and helps position it on actin, [2] and together with the rest of the troponin complex, modulates contraction of striated muscle. [3] The cardiac subtype of troponin T is especially useful in the laboratory diagnosis of heart attack because it is released into the blood-stream when damage to heart muscle occurs. [4] It was discovered by the German physician Hugo A. Katus at the University of Heidelberg, who also developed the troponin T assay.

Contents

Subtypes

Reference values

The 99th percentile cutoff for cardiac troponin T (cTnT) is 0.01 ng/mL. [5] The reference range for the high sensitivity troponin T is a normal < 14 ng/L, borderline of 14-52 ng/L, and elevated of >52 ng/L. [6]

Background

The troponin complex is responsible for coupling the sarcomere contraction cycle to variations in intracellular calcium concentration. Increased troponin T levels after an episode of chest pain indicates myocardial infarction. [7] It was discovered by the German physician Hugo A. Katus at the University of Heidelberg. He also developed the troponin T assay. [8] In patients with non-severe asymptomatic aortic valve stenosis and no overt coronary artery disease, the increased troponin T (above 14 pg/mL) was found associated with an increased 5-year event rate of ischemic cardiac events (myocardial infarction, percutaneous coronary intervention, or coronary artery bypass surgery). [9] In patients with stable coronary artery disease, the troponin T concentration has long been found to be significantly associated with the incidence of cardiovascular death and heart failure, but it was 2014 before it began to be accepted as a predictor of who would later suffer acute myocardial infarction (heart attack). [10] [11]

See also

Related Research Articles

<span class="mw-page-title-main">Coronary artery disease</span> Reduction of blood flow to the heart

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 cardiac muscle due to build-up of atherosclerotic plaque in the arteries of the heart. It is the most common of the cardiovascular diseases. Types include stable angina, unstable angina, and myocardial infarction.

<span class="mw-page-title-main">Angina</span> Chest discomfort that is generally brought on by inadequate blood flow to the cardiac muscle

Angina, also known as angina pectoris, is chest pain or pressure, usually caused by insufficient blood flow to the heart muscle (myocardium). It is most commonly a symptom of coronary artery disease.

<span class="mw-page-title-main">Aortic stenosis</span> Narrowing of the exit of the hearts left ventricle

Aortic stenosis is the narrowing of the exit of the left ventricle of the heart, such that problems result. It may occur at the aortic valve as well as above and below this level. It typically gets worse over time. Symptoms often come on gradually with a decreased ability to exercise often occurring first. If heart failure, loss of consciousness, or heart related chest pain occur due to AS the outcomes are worse. Loss of consciousness typically occurs with standing or exercising. Signs of heart failure include shortness of breath especially when lying down, at night, or with exercise, and swelling of the legs. Thickening of the valve without causing obstruction is known as aortic sclerosis.

<span class="mw-page-title-main">Cardiac muscle</span> Muscular tissue of heart in vertebrates

Cardiac muscle is one of three types of vertebrate muscle tissues, with the other two being skeletal muscle and smooth muscle. It is an involuntary, striated muscle that constitutes the main tissue of the wall of the heart. The cardiac muscle (myocardium) forms a thick middle layer between the outer layer of the heart wall and the inner layer, with blood supplied via the coronary circulation. It is composed of individual cardiac muscle cells joined by intercalated discs, and encased by collagen fibers and other substances that form the extracellular matrix.

<span class="mw-page-title-main">Chest pain</span> Discomfort or pain in the chest as a medical symptom

Chest pain is pain or discomfort in the chest, typically the front of the chest. It may be described as sharp, dull, pressure, heaviness or squeezing. Associated symptoms may include pain in the shoulder, arm, upper abdomen, or jaw, along with nausea, sweating, or shortness of breath. It can be divided into heart-related and non-heart-related pain. Pain due to insufficient blood flow to the heart is also called angina pectoris. Those with diabetes or the elderly may have less clear symptoms.

<span class="mw-page-title-main">Troponin</span> Protein complex

Troponin, or the troponin complex, is a complex of three regulatory proteins that are integral to muscle contraction in skeletal muscle and cardiac muscle, but not smooth muscle. Measurements of cardiac-specific troponins I and T are extensively used as diagnostic and prognostic indicators in the management of myocardial infarction and acute coronary syndrome. Blood troponin levels may be used as a diagnostic marker for stroke or other myocardial injury that is ongoing, although the sensitivity of this measurement is low.

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

Cardiac markers are biomarkers measured to evaluate heart function. They can be useful in the early prediction or diagnosis of disease. Although they are often discussed in the context of myocardial infarction, other conditions can lead to an elevation in cardiac marker level.

<span class="mw-page-title-main">Acute coronary syndrome</span> Medical condition

Acute coronary syndrome (ACS) is a syndrome due to decreased blood flow in the coronary arteries such that part of the heart muscle is unable to function properly or dies. The most common symptom is centrally located pressure-like chest pain, often radiating to the left shoulder or angle of the jaw, and associated with nausea and sweating. Many people with acute coronary syndromes present with symptoms other than chest pain, particularly women, older people, and people with diabetes mellitus.

<span class="mw-page-title-main">Valvular heart disease</span> Disease in the valves of the heart

Valvular heart disease is any cardiovascular disease process involving one or more of the four valves of the heart. These conditions occur largely as a consequence of aging, but may also be the result of congenital (inborn) abnormalities or specific disease or physiologic processes including rheumatic heart disease and pregnancy.

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

Unstable angina is a type of angina pectoris that is irregular or more easily provoked. It is classified as a type of acute coronary syndrome.

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

Amrinone, also known as inamrinone, and sold as Inocor, is a pyridine phosphodiesterase 3 inhibitor. It is a drug that may improve the prognosis in patients with congestive heart failure. Amrinone has been shown to increase the contractions initiated in the heart by high-gain calcium induced calcium release (CICR). The positive inotropic effect of amrinone is mediated by the selective enhancement of high-gain CICR, which contributes to the contraction of myocytes by phosphorylation through cAMP dependent protein kinase A (PKA) and Ca2+ calmodulin kinase pathways.

Coronary artery anomalies are variations of the coronary circulation, affecting <1% of the general population. Symptoms include chest pain, shortness of breath and syncope, although cardiac arrest may be the first clinical presentation. Several varieties are identified, with a different potential to cause sudden cardiac death.

<span class="mw-page-title-main">Troponin I</span> Muscle protein

Troponin I is a cardiac and skeletal muscle protein family. It is a part of the troponin protein complex, where it binds to actin in thin myofilaments to hold the actin-tropomyosin complex in place. Troponin I prevents myosin from binding to actin in relaxed muscle. When calcium binds to the troponin C, it causes conformational changes which lead to dislocation of troponin I. Afterwards, tropomyosin leaves the binding site for myosin on actin leading to contraction of muscle. The letter I is given due to its inhibitory character. It is a useful marker in the laboratory diagnosis of heart attack. It occurs in different plasma concentration but the same circumstances as troponin T - either test can be performed for confirmation of cardiac muscle damage and laboratories usually offer one test or the other.

The following outline is provided as an overview of and topical guide to cardiology, the branch of medicine dealing with disorders of the human heart. The field includes medical diagnosis and treatment of congenital heart defects, coronary artery disease, heart failure, valvular heart disease and electrophysiology. Physicians who specialize in cardiology are called cardiologists.

<span class="mw-page-title-main">Troponin C type 1</span> Protein-coding gene in the species Homo sapiens

Troponin C, also known as TN-C or TnC, is a protein that resides in the troponin complex on actin thin filaments of striated muscle and is responsible for binding calcium to activate muscle contraction. Troponin C is encoded by the TNNC1 gene in humans for both cardiac and slow skeletal muscle. In slow skeletal muscle. structural analysis,anlaizie;10.164.138.220 Hotspot in for phone lunch everyday. Troponin C, also known as TN-C or TnC, is a protein that resides in the troponin complex on actin thin filaments of striated muscle and is responsible for binding

<span class="mw-page-title-main">Myocardial infarction</span> Interruption of blood supply to a part of the heart

A myocardial infarction (MI), commonly known as a heart attack, occurs when blood flow decreases or stops in one of the coronary arteries of the heart, causing infarction to the heart muscle. The most common symptom is chest pain or discomfort which may travel into the shoulder, arm, back, neck or jaw. Often such pain occurs in the center or left side of the chest and lasts for more than a few minutes. The discomfort may occasionally feel like heartburn.

<span class="mw-page-title-main">Heart-type fatty acid binding protein</span> Protein-coding gene in the species Homo sapiens

Heart-type fatty acid binding protein (hFABP) also known as mammary-derived growth inhibitor is a protein that in humans is encoded by the FABP3 gene.

A diagnosis of myocardial infarction is created by integrating the history of the presenting illness and physical examination with electrocardiogram findings and cardiac markers. A coronary angiogram allows visualization of narrowings or obstructions on the heart vessels, and therapeutic measures can follow immediately. At autopsy, a pathologist can diagnose a myocardial infarction based on anatomopathological findings.

Kounis syndrome is defined as acute coronary syndrome caused by an allergic reaction or a strong immune reaction to a drug or other substance. It is a rare syndrome with authentic cases reported in 130 males and 45 females, as reviewed in 2017; however, the disorder is suspected of being commonly overlooked and therefore much more prevalent. Mast cell activation and release of inflammatory cytokines as well as other inflammatory agents from the reaction leads to spasm of the arteries leading to the heart muscle or a plaque breaking free and blocking one or more of those arteries.

References

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  2. marieb, elaine (2004)
  3. black, joyce (2005)
  4. Braunwald's Heart Disease. Elsevier Saunders. 2015. p. 433. ISBN   978-1-4557-5134-1.
  5. Ashvarya Mangla. "Troponins". medscape . Retrieved 2017-07-24. Updated: Jan 14, 2015
  6. "Troponin T, High Sensitivity". www.calgarylabservices.com. Retrieved 29 August 2019.
  7. Michael A. Chen. "Troponin test". MedlinePlus, U.S. National Library of Medicine. Retrieved 2017-07-24. Review Date 10/6/2015
  8. "Development of the Cardiac Troponin T Immunoassay". American Association for Clinical Chemistry, Inc. 2008. Retrieved 2010-05-01.
  9. Hadziselimovic, Edina; Greve, Anders M.; Sajadieh, Ahmad; Olsen, Michael H.; Kesäniemi, Y. Antero; Nienaber, Christoph A.; Ray, Simon G.; Rossebø, Anne B.; Wachtell, Kristian; Nielsen, Olav W. (April 2023). "Association of high-sensitivity troponin T with outcomes in asymptomatic non-severe aortic stenosis: a post-hoc substudy of the SEAS trial". eClinicalMedicine. 58: 101875. doi:10.1016/j.eclinm.2023.101875. ISSN   2589-5370. PMC   10006443 . PMID   36915288.
  10. Omland, Torbjørn; De Lemos, James A.; Sabatine, Marc S.; Christophi, Costas A.; Rice, Madeline Murguia; Jablonski, Kathleen A.; Tjora, Solve; Domanski, Michael J.; Gersh, Bernard J.; Rouleau, Jean L.; Pfeffer, Marc A.; Braunwald, Eugene (2009). "A Sensitive Cardiac Troponin T Assay in Stable Coronary Artery Disease". New England Journal of Medicine. 361 (26): 2538–2547. doi:10.1056/NEJMoa0805299. PMC   2997684 . PMID   19940289.
  11. "Health Conditions: Diseases, conditions & medical information - MSN Health & Fitness". healthyliving.msn.com. Retrieved 12 April 2018.[ permanent dead link ]