Cardiac Troponin I and Troponin T: Recent Players in the Field of Myocardial Markers

Chapelle, Jean-Paul

doi:10.1515/cclm.1999.002

Cited by 53 publications

(31 citation statements)

References 88 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…TnI is the inhibitory subunit that can bind to actin-tropomyosin and prevent muscle contraction by inhibition of actin-activated myosin (actomyosin) ATPase activity (33). TnI has received considerable attention as a serum biomarker of myocardial tissue damages (2,31) and as a key phosphoprotein that regulates cardiac contractile function (13,40). Its role in mediating cardiac dysfunction in humans and experimental animals is controversial and continues to be actively investigated.…”

mentioning

confidence: 99%

Progressive troponin I loss impairs cardiac relaxation and causes heart failure in mice

Liu

Zhang³

et al. 2007

American Journal of Physiology-Heart and Circulatory Physiology

View full text Add to dashboard Cite

XP. Progressive troponin I loss impairs cardiac relaxation and causes heart failure in mice. Am J Physiol Heart Circ Physiol 293: H1273-H1281, 2007. First published May 25, 2007; doi:10.1152/ajpheart.01379.2006.-Cardiac troponin I (TnI) knockout mice exhibit a phenotype of sudden death at 17-18 days after birth due to a progressive loss of TnI. The objective of this study was to gain insight into the physiological consequences of TnI depletion and the cause of death in these mice. Cardiac function was monitored serially between 12 and 17 days of age by using high-resolution ultrasonic imaging and Doppler echocardiography. Two-dimensional B-mode and anatomical M-mode imaging and Doppler echocardiography were performed using a high-frequency (ϳ20 -45 MHz) ultrasound imaging system on homozygous cardiac TnI mutant mice (cTnI Ϫ/Ϫ ) and wild-type littermates. On day 12, cTnI Ϫ/Ϫ mice were indistinguishable from wildtype mice in terms of heart rate, atrial and LV (LV) chamber dimensions, LV posterior wall thickness, and body weight. By days 16 through 17, wild-type mice showed up to a 40% increase in chamber dimensions due to normal growth, whereas cTnI Ϫ/Ϫ mice showed increases in atrial dimensions of up to 97% but decreases in ventricular dimensions of up to 70%. Mitral Doppler analysis revealed prolonged isovolumic relaxation time and pronounced inversion of the mitral E/A ratio (early ventricular filling wave-to-late atrial contraction filling wave) only in cTnI Ϫ/Ϫ mice indicative of impaired LV relaxation. cTnI Ϫ/Ϫ mouse hearts showed clear signs of failure on day 17, characterized by Ͼ50% declines in cardiac output, ejection fraction, and fractional shortening. B-mode echocardiography showed a profoundly narrowed tube-like LV and enlarged atria at this time. Our data are consistent with TnI deficiency causing impaired LV relaxation, which leads to diastolic heart failure in this model. damaged relaxation; echocardiography; Doppler analysis THE CONTRACTILE SARCOMERIC PROTEINS consist of a highly ordered arrangement of myosin thick filaments, actin thin filaments, and associated proteins, such as the troponin-tropomyosin complex. Contractile sarcomeric protein mutations, truncations, and deletions have been identified for various cardiac disorders in humans and experimental animals (8,16,18,23,25,28

show abstract

mentioning

confidence: 99%

Progressive troponin I loss impairs cardiac relaxation and causes heart failure in mice

Liu

Zhang³

et al. 2007

American Journal of Physiology-Heart and Circulatory Physiology

View full text Add to dashboard Cite

show abstract

“…Key Words: troponin Ⅲ myocardial infarction Ⅲ biological markers Ⅲ diagnosis Ⅲ blotting, western I t is widely accepted that the presence of cardiac troponin I or T (cTnI or cTnT) in blood serum indicates myocardial damage; thus, cTnI and cTnT are considered specific biochemical markers for acute myocardial infarction (AMI). [1][2][3] Despite the widespread use of cTnI and cTnT detection as a diagnostic tool in acute coronary syndromes, problems arise from variations in the sensitivity, selectivity, and specificity of various commercially available diagnostic cTnI immunoassay kits. 4 -7 These differences are due to (1) the lack of mass standardization, 8 -10 (2) the presence of post-translationally modified cTnI in the serum, and (3) variations in antibody cross-reactivities to the various detectable forms of cTnI.…”

mentioning

confidence: 99%

“…[1][2][3] Despite the widespread use of cTnI and cTnT detection as a diagnostic tool in acute coronary syndromes, problems arise from variations in the sensitivity, selectivity, and specificity of various commercially available diagnostic cTnI immunoassay kits. 4 -7 These differences are due to (1) the lack of mass standardization, 8 -10 (2) the presence of post-translationally modified cTnI in the serum, and (3) variations in antibody cross-reactivities to the various detectable forms of cTnI.…”

mentioning

confidence: 99%

Extensive Troponin I and T Modification Detected in Serum From Patients With Acute Myocardial Infarction

2000

View full text Add to dashboard Cite

Background-Cardiac troponin I and T (cTnI and cTnT) are specific biochemical serum markers for acute myocardial infarction (AMI). However, cTnI diagnostic assays are plagued by difficulties, resulting in Ն20-fold differences in measured values. These discrepancies may result from the release of the numerous cTnI modification products that are present in ischemic myocardium. The resolution of these discrepancies requires an investigation of the exact forms of cTnI present in the bloodstream of patients after myocardial injury. Methods and Results-A western blot-direct serum analysis protocol was developed that allowed us to detect intact cTnI and a spectrum of up to 11 modified products in the serum from patients with AMI. For the first time, we document both a cTnI degradation pattern and the existence of phosphorylated cTnI in serum. The number and extent of these modifications reflect patterns similar to the time profiles of the routine clinical serum markers of total creatine kinase, creatine kinase-MB, and cTnI (determined by ELISA). Data from in vitro experiments, which were undertaken to study the degradation of human recombinant cTnI and cTnT when spiked in serum, indicate that some modification products present in patient serum existed in the myocardium and that recombinant cTnI alteration dramatically reduces the detectability of cTnI by the Immuno1 assay over time (our assay was unaffected). Key Words: troponin Ⅲ myocardial infarction Ⅲ biological markers Ⅲ diagnosis Ⅲ blotting, western I t is widely accepted that the presence of cardiac troponin I or T (cTnI or cTnT) in blood serum indicates myocardial damage; thus, cTnI and cTnT are considered specific biochemical markers for acute myocardial infarction (AMI). [1][2][3] Despite the widespread use of cTnI and cTnT detection as a diagnostic tool in acute coronary syndromes, problems arise from variations in the sensitivity, selectivity, and specificity of various commercially available diagnostic cTnI immunoassay kits. 4 -7 These differences are due to (1) the lack of mass standardization, 8 -10 (2) the presence of post-translationally modified cTnI in the serum, and (3) variations in antibody cross-reactivities to the various detectable forms of cTnI. 10,11 Although cTnT is thought to be unaffected by such problems, this remains to be proven: thus far, only one manufacturer has marketed a diagnostic cTnT assay. The underlying reason for this controversy is the inability to determine reliably the exact forms and amounts of cTnI and cTnT present in blood. Conclusions-ThisOn the basis of previous findings, some have proposed that only a small amount of free intact cTnI is detectable in blood, with the predominant form being a complex between cTnI and cardiac tropinin C. 11-13 However, post-translational modifications, including selective degradation, covalent complex formation, and phosphorylation of cTnI, occur in the myocardium of ischemic-reperfused rat hearts 14 -16 and human postischemic myocardium. 17,18 In fact, these modification products, and ...

show abstract

“…5 It has been observed that this structural cell protein may be detected in the blood of patients with acute coronary syndrome, 6 after coronary angioplasty, 7 in heart failure, 8 acute myocarditis, 9 and other clinical situations in which conventional markers of myocyte necrosis are often negative. Thus, the new concept of 'minor myocardial damage' has emerged.…”

mentioning

confidence: 99%

Serum cardiac troponin I levels and ECG/Echo monitoring in breast cancer patients undergoing high-dose (7 g/m2) cyclophosphamide

Morandi

Ruffini

Benvenuto

et al. 2001

Bone Marrow Transplant

View full text Add to dashboard Cite

Summary:High-dose cyclophosphamide (HD-CTX) is largely employed in high-dose chemotherapy (HD-CHT) protocols. HD-CTX dose-limiting toxicity expresses itself as cardiac toxicity which is fatal in a minority of patients. The pathophysiology of HD-CTX-associated cardiotoxicity is still poorly understood. Autopsy studies in patients who died from acute HD-CTX-induced cardiac toxicity revealed hemorrhagic myocardial cell death and interstitial edema. Recently troponins, in particular troponin I (cTnI), have been found to represent a uniquely sensitive and specific marker of myocyte membrane integrity and therefore to increase in response to minimal myocardial cell damage in different settings, including doxorubicin-induced cardiotoxicity. We performed a multiparametric cardiologic monitoring in 16 consecutive breast cancer patients undergoing HD-CTX by means of serial ECG registrations and cardiac enzymes (CPK, CPK-MB and cTnI) determinations plus echocardiography in order to clarify acute cardiac events following HD-CTX administration. Neither overt cardiac toxicity nor cardiac enzymes elevation were recorded. Serial ECGs revealed in six cases little and reversible reduction of QRS voltage and/or ST abnormalities. Echo monitoring showed in four cases mild and transient increase of LV diastolic/systolic diameter/volume without decrease of FS% or EF% below normal values: in two of them abnormalities of diastolic function (E/A mitral doppler ratio) were also recorded. We conclude that our protocol of HD-CTX administration does not cause myocardial cell damage as analyzed by serum cTnI levels, thus suggesting that myocyte membrane injury may not be the first direct mechanism of HD-CTX cardiotoxicity. ECG (ie QRS voltages ) and Echo (ie E/A ratio) monitoring leads us to hypothesize that slight interstitial edema with reduction of LV diastolic compliance may be initial signs of cardiac dysfunction in this clinical setting. Bone Marrow Transplantation (2001) 28, 277-282.

show abstract

Cardiac Troponin I and Troponin T: Recent Players in the Field of Myocardial Markers

Cited by 53 publications

References 88 publications

Progressive troponin I loss impairs cardiac relaxation and causes heart failure in mice

Progressive troponin I loss impairs cardiac relaxation and causes heart failure in mice

Extensive Troponin I and T Modification Detected in Serum From Patients With Acute Myocardial Infarction

Serum cardiac troponin I levels and ECG/Echo monitoring in breast cancer patients undergoing high-dose (7 g/m2) cyclophosphamide

Contact Info

Product

Resources

About