Differential reactivity of cardiac and skeletal muscle from various species in a cardiac troponin I immunoassay

Abstract

To identify a blood test that can differentiate cardiac from skeletal muscle injury in animals, we compared tissue reactivities for various species with the use of an immunoassay for human cardiac troponin I (cTnI). Tissue reactivity varied as a function of the homology of tissue troponin with human cTnI. Cardiac reactivity in large mammals was equivalent to cTnI, 9.8 ± 0.6 mg/g, and was 2-fold, 10-fold, and 100-fold greater than in small mammals, birds, and fish, respectively. Skeletal muscle reactivity was equivalent to cTnI, 5.1 ± 0.6 μg/g, in all species except fish, in which it was 50% lower. The ratio of reactivities of cardiac and skeletal muscle was: 1800 in large mammals, 1100 in small mammals, 230 in birds, and 43 in fish. We conclude that cTnI is a powerful candidate in mammals, a possible candidate in birds, but unlikely to be of use in fish as a sensitive and tissue-selective diagnostic test for cardiac injury.

Validation of a Commercially Available Immunoassay for the Measurement of Bovine Cardiac Troponin I

“…Capture antibodies used in commercially available cTnI assays have negligible cross reactivity with skeletal muscle troponin. 19,27,28 We did not observe a clinically relevant increase in cTnI concentration when various amounts of skeletal muscle homogenate were added. The increase in cTnI concentration was not proportionate to the volume of skeletal muscle homogenate added.…”

“…Results of this study are similar to those of previous studies in other species. 16,[19][20][21] but cannot necessarily be extrapolated to results of studies with different cTnI assays for the detection of bovine cTnI. Additional research on the evaluation of circulating cTnI in cows with naturally occurring myocardial injury secondary to viral or bacterial infections, traumatic reticuloperitonitis, glycoside and ionophore toxicity, and nutritional deficiencies affecting myocardial integrity and function as well as the effect of noncardiac diseases on circulating cTnI concentrations are needed.…”

“…Bovine cTnI has high amino acid sequence homology (4 96%) with human cTnI. 16 Therefore, it is anticipated that antibodies against human cTnI used in commercially available immunoassays will cross-react with bovine cTnI. The objective of the present study was to evaluate the analytical performance of the ADVIA Centaur TnI-Ultra immunoassay a for the detection of circulating bovine cTnI and to determine a reference range for serum cTnI concentration in healthy cows.…”

Effect of clopidogrel on the expression of inflammatory markers in rabbit ischemic coronary artery

“…After 24 h, the rabbits were anesthetized exanguinated and the entire ischemic coronary artery removed and quickly frozen in liquid nitrogen for molecular biology determinations. The blood was collected in both acid-citrate dextrose (ACD) for P-selectin evaluation in the platelet surface and in a glass tube for sera isolation to determine troponin I. Sera troponin I was determined using a commercially available Dade-Behring immunoassay for human cardiac troponin I, which has been shown to react with rabbit cardiac troponin I (Zaninotto et al, 1996;O'Brien et al, 1997). The experimental procedure was approved by the institutional Animal Care and Use Committee.…”

Right ventricular pressure dynamics and stress echocardiography in pharmacological and exercise stress testing

“…With significant ischaemia and anoxia resulting in myocardial cell necrosis and death, larger concentrations of cTnI are released. The majority of cTnI is structurally bound to thin filaments, however a small percentage in humans and dogs is present as an unbound cytosolic pool (Mair et al 1996;O'Brien et al 1997;Schober et al 2002). This cytosolic pool may account for the early, mild increase in cTnI, not associated with ischemic events.…”