Troponin T (shortened TnT or TropT) is a part of the

troponin image:Troponin Ribbon Diagram.png, 400px, Ribbon representation of the human cardiac troponin core complex (52 kDa core) in the calcium-saturated form. Blue = troponin C; green = troponin I; magenta = troponin T.; ; rendered with PyMOL Troponin, ...

complex, which are

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respo ...

s integral to the contraction of skeletal and heart muscles. They are expressed in skeletal and cardiac

myocyte A muscle cell is also known as a myocyte when referring to either a cardiac muscle cell (cardiomyocyte), or a smooth muscle cell as these are both small cells. A skeletal muscle cell is long and threadlike with many nuclei and is called a muscl ...

s. Troponin T binds to

tropomyosin Tropomyosin is a two-stranded alpha-helical, coiled coil protein found in actin-based cytoskeletons. Tropomyosin and the actin skeleton All organisms contain organelles that provide physical integrity to their cells. These type of organelles a ...

and helps position it on

actin Actin is a family of globular multi-functional proteins that form microfilaments in the cytoskeleton, and the thin filaments in muscle fibrils. It is found in essentially all eukaryotic cells, where it may be present at a concentration of over ...

, and together with the rest of the troponin complex, modulates contraction of striated muscle. 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. It was discovered by the German physician Hugo A. Katus at the

University of Heidelberg } Heidelberg University, officially the Ruprecht Karl University of Heidelberg, (german: Ruprecht-Karls-Universität Heidelberg; la, Universitas Ruperto Carola Heidelbergensis) is a public research university in Heidelberg, Baden-Württemberg, ...

, who also developed the troponin T

assay An assay is an investigative (analytic) procedure in laboratory medicine, mining, pharmacology, environmental biology and molecular biology for qualitatively assessing or quantitatively measuring the presence, amount, or functional activity of a ...

Subtypes

* Slow skeletal troponin T1,

TNNT1 Slow skeletal muscle troponin T (sTnT) is a protein that in humans is encoded by the ''TNNT1'' gene. The TNNT1 gene is located at 19q13.4 in the human chromosomal genome, encoding the slow twitch skeletal muscle isoform of troponin T (ssTnT). ss ...

(19q13.4, ) * Cardiac troponin T2,

TNNT2 Cardiac muscle troponin T (cTnT) is a protein that in humans is encoded by the ''TNNT2'' gene. Cardiac TnT is the tropomyosin-binding subunit of the troponin complex, which is located on the thin filament of striated muscles and regulates muscle c ...

(1q32, ) * Fast skeletal troponin T3,

TNNT3 Fast skeletal muscle troponin T (fTnT) is a protein that in humans is encoded by the ''TNNT3'' gene. The TNNT3 gene is located at 11p15.5 in the human genome, encoding the fast skeletal muscle isoform of troponin T (fsTnT). fsTnT is an ~31-kDa pr ...

(11p15.5, )

Reference values

The 99th percentile cutoff for cardiac troponin T (cTnT) is 0.01 ng/mL. 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.

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 A myocardial infarction (MI), commonly known as a heart attack, occurs when blood flow decreases or stops to the coronary artery of the heart, causing damage to the heart muscle. The most common symptom is chest pain or discomfort which may ...

. It was discovered by the German physician Hugo A. Katus at the

. He also developed the troponin T assay. In patients with stable

coronary artery 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 pla ...

, 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

(heart attack).

Significance in Covid-19 mRNA vaccinations

A study carried out by the

University of Basel The University of Basel (Latin: ''Universitas Basiliensis'', German: ''Universität Basel'') is a university in Basel, Switzerland. Founded on 4 April 1460, it is Switzerland's oldest university and among the world's oldest surviving universit ...

and the

University Hospital of Basel The University Hospital of Basel (German: ''Universitätsspital Basel'', USB), in Basel, is one of the five university hospitals of Switzerland. Since 1842 it is located in a former palace, the Markgräflerhof. USB brings together 50 clinics, u ...

found that a

Covid-19 Coronavirus disease 2019 (COVID-19) is a contagious disease caused by a virus, the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The first known case was COVID-19 pandemic in Hubei, identified in Wuhan, China, in December ...

mRNA vaccination significantly elevates the cardiac troponin T levels in the blood stream. 3 % of the study subjects have shown elevated amounts of the protein after their 3rd vaccination. The effect was most pronounced among young men. It is not yet clear what the mechanism is, and the observed troponin levels were still much lower than in clinically significant heart disease. Given that previous studies only registered 35 cases of heart muscle inflammation per million subjects, the involved researchers were surprised by the results.

References

External links