equis - Articles
Blood: troponin I
Overview
- In humans, increased serum concentrations of cardiac troponins provide a sensitive and specific marker of myocardial damage, including physical or metabolic myocardial injury, myocardial ischemia or necrosis.
- Cardiac troponin has been studied intensively in man, and it has been found that there is a high (95%) structural agreement between mammals, making it likely that monoclonal antibodies established from the human field will be a useful in veterinary clinical pathology.
- The cardiac troponins are thin filament-associated regulatory proteins of the heart muscle. They are crucial to the interaction between actin and myosin and occur at regular intervals along the tropomyosin molecule.
- Cardiac troponin I (I for inhibition) is uniquely expressed in the myocardium and is a potent inhibitor of the process of actin-myosin cross-bridge formation.
- Cardiac specificity for CTnI is 100%.
Uses
Alone
- Detection of myocardial cell injury of:
- Inflammatory (myocarditis Heart: endocarditis ).
- Physical (myocardial contusion).
- Metabolic (secondary to renal pathology, cushing's disease Pituitary pars intermedia dysfunction (PPID) ).
- Toxic (bacterial endotoxemia Endotoxemia: overview , certain drugs, ionophore toxicity).
- Ischemic (tachycardia induced) or infarctive etiology.
- A significant amount of research has shown the usefulness of measuring cardiac troponin to detect subtle or ongoing pathology following monesin or lascaloid poisoning.
In combination
- With Lactate dehydrogenase Blood: biochemistry - lactate dehydrogenase isoenzyme 2, electrocardiography (ECG) Heart: echocardiography , doppler and cardiac ultrasonography, in the evaluation of suspected cardiac abnormality.
Other points
- Not offered as part of routine equine profile.
- Must request separately.
Sampling
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Tests
Methodologies
- Commercially available ELISA test (human).
Availability
- Limited.
- An increasing number of laboratories are now offering this test.
Validity
Sensitivity
- A high sensitivity is reported in dogs and humans but is yet to be established in horses.
Specificity
- CTnI is highly specific for myocardial pathology.
Predictive value
- CTnI has not been associated with survival, but has been associated with the degree of cardiac damage at necropsy.
Technique intrinsic limitations
- Purified equine CTnI is not available and thus absolute assay specificity cannot be achieved. However, CTnI is highly conserved among mammalian species (>95% DNA homology between human and bovine cTnI).
- Though CTnI is specific for cardiac pathology it may be elevated in diseases in which cardiac disease is not the primary pathology, eg endotoxemia, renal disease and pulmonary embolism.
- New test in equine clinical pathology, too few studies yet to fully validate.
- Laboratory evaluation is currently required, however a point-of-care analyzer has undergone preliminary investigation.
Result Data
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Further Reading
Publications
Refereed papers
- Recent references from PubMed and VetMedResource.
- Rossi T M et al (2014) Troponin assays in the assessment of the equine myocardium. Equine Vet J 46 (3), 270-275 PubMed.
- Decloedt A, Verheyen T et al (2012) Acute and long-term cardiomyopathy and delayed neurotoxicity after accidental lasalocid poisoning in horses. J Vet Intern Med 26 (4), 1005-1011 PubMed.
- Nath L C, Anderson G A et al (2012) Serum cardiac troponin I concentrations in horses with cardiac disease. Aust Vet J 90 (9), 351-357 PubMed.
- Kraus M S, Jesty S A et al (2010) Measurement of plasma cardiac troponin I concentration by use of a point-of-care analyzer in clinically normal horses and horses with experimentally induced cardiac disease. Am J Vet Res 71 (1), 55-59 PubMed.
- Divers T J, Kraus M S et al (2009) Clinical findings and serum cardiac troponin I concentrations in horses after intragastric administration of sodium monensin. J Vet Diag Invest 21 (3), 338-343 PubMed.
- Phillips W, Giguère S et al (2003) Cardiac Troponin I in pastured and race-training Thoroughbred horses. J Vet Intern Med 17 (4), 597-599 PubMed.
- Cornelisse C J, Schott H C, Olivier N B et al (2000) Concentration of cardiac troponin I in a horse with a ruptured aortic regurgitation jet lesion and ventricular tachycardia. JAVMA 217 (2), 231-235 PubMed.
Other sources of information
- Schober K E, Kirbach B, Cornand C & Oechtering G (2001) Circulating Cardiac Tropinins in Small Animals. In: Proc 19th ACVIM.