Myocardial tissue troponins T and I

Myocardial tissue troponins T and I

An immunohistochemical study in experimental

models of myocardial ischemia

Michael C. Fishbeina,*, Tiffany Wanga, Maria Matijasevica,Longsheng Honga, Fred S. Appleb

aDivision of Anatomic Pathology, Department of Pathology and Laboratory Medicine, UCLA Center for the Health Sciences,

A7-149 CHS, 10833 Le Conte Avenue, Los Angeles, CA 90095-1732, USAbDepartment of Laboratory Medicine and Pathology, Hennepin County Medical Center, University of Minnesota School of Medicine,

914 S. 8th Street, Minneapolis, MN 55404, USA

Received 4 August 2002; received in revised form 30 September 2002; accepted 12 November 2002

Abstract

Background: Cardiac troponins T (cTnT) and I (cTnI) are proven diagnostic and risk stratification biomarkers in patients with acute

coronary syndromes. To date, no immunohistochemical studies have been performed which allow visualization of the time course and pattern

of myocardial troponin egress from the myocardium during the early evolution of ischemic injury in experimental systems. Methods: We

studied archival formalin-fixed, paraffin-embedded myocardium from 50 experimental animals (dogs, pigs and rats) that had undergone

permanent coronary occlusion (n = 34) for 0.5–6 h or occlusion of 0.75–6 h followed by reperfusion (n = 16). Histologic sections that

included ischemic and nonischemic myocardium were studied by immunohistochemistry with three different antibodies to human cTnI and

one to cTnT, using a standard avidin–biotin–peroxidase system. Results: All antibodies detected cTnT or cTnI in normal myocardium and its

loss from necrotic myocardium, in some cases as early as 30 min after coronary occlusion, before histologic evidence of necrosis was present.

Loss was nonuniform, being greater at the periphery of the infarcts then at their central regions. Usually, loss of cTnT appeared greater

than loss of cTnI. With reperfusion, findings were similar to those after permanent occlusion, except that there was a greater contrast between

loss at the periphery compared to the loss in the central region. Considerable residual staining persisted for hours after occlusion, indicating

delayed release over time, concordant with sustained serum elevations in patients with acute myocardial infarction. No loss of staining was

observed in nonnecrotic myocardium. Conclusions: Immunohistochemical staining using antibodies to human cTnT and cTnI can be used to

visualize cardiac troponins and document their loss in histologic sections of myocardium in different animal species. Loss of cTnT and cTnI

occurs very early following ischemic injury and may precede histologic evidence of necrosis, but does not occur in myocardium that is not

necrotic. Immunohistochemical staining of hearts for cTnT and cTnI can assist in the often difficult recognition of myocardial necrosis at

autopsy, in patients suspected of dying from acute myocardial ischemia. D 2003 Elsevier Inc. All rights reserved.

Keywords: Immunohistochemistry; Troponins; Myocardial Necrosis

1. Introduction

Until recently, measurement of creatine kinase (CK)

and its myocardial isoenzyme (CK-MB) in the blood have

been the gold standard for the enzymatic diagnosis of

acute myocardial infarction [1]. Recent data indicate

measurement of cardiac troponins T (cTnT) and I (cTnI)

may be even more useful in diagnosing acute myocardial

infarction and for risk stratification in acute myocardial

ischemia [2–5]. Indeed, a joint committee of the Amer-

ican College of Cardiology and the European Society of

Cardiology has recommended that cardiac troponin

replace CK-MB in the evaluation of patients for myocar-

dial ischemia/infarction, as cardiac troponin measurements

appear to be more sensitive, myocardial-tissue specific,

1054-8807/03/$ – see front matter D 2003 Elsevier Inc. All rights reserved.

doi:10.1016/S1054-8807(02)00188-6

Abbreviations: CK, creatine kinase; cTnI, cardiac troponin I; cTnT,

cardiac troponin T; EM, electron microscopy; LDH, lactic dehydrogenase;

NHS, normal horse serum; PAS, periodic acid Schiff; PBS, phosphate-

buffered saline; TTC, triphenyl tetrazolium chloride

* Corresponding author. Tel.: +1-310-825-9731; fax: +1-310-794-4161.

E-mail address: [email protected] (M.C. Fishbein).

Cardiovascular Pathology 12 (2003) 65–71

and remain elevated longer after the onset of myocardial

infarction [6].

We have previously shown that the presence and

absence of the myocardial proteins CK-M, CK-B, myo-

globin, LDH-1, and cytosolic and mitochondrial aspartate

aminotransferase can be demonstrated in formalin-fixed,

paraffin-embedded tissues by immunohistochemical stain-

ing techniques [7–11]. Furthermore, we demonstrated loss

of these enzymes in necrotic human myocardium from

autopsied patients dying with myocardial infarction [8–

12]. In experimental models of myocardial infarction,

using electron microscopy (EM), gross triphenyl tetrazo-

lium chloride (TTC) staining, and periodic acid-Schiff

(PAS) staining for glycogen, we showed that loss of these

proteins did not occur with ischemia alone, but could be

demonstrated in necrotic myocardium as early as 3 h after

coronary occlusion [13].

Since we have retained paraffin blocks from our previous

immunohistochemical studies of well-characterized experi-

mental myocardial ischemic injury, we were able to restudy

these cases using antibodies to cTnI and cTnT to character-

ize the patterns of staining in experimental models in three

different animal species. The goals were to: (1) examine the

time course and pattern of loss of troponins from ischemic

myocardium; (2) to determine if troponin loss precedes

histologic evidence of necrosis; (3) to determine the spe-

cificity of loss of troponins as a marker of myocardial

necrosis; and (4) to determine if immunohistochemical

visualization of cardiac troponins would, therefore, be a

useful tool for the evaluation of myocardial ischemic injury

in experimental studies and in human autopsy material.

Preliminary immunohistochemical studies in autopsied

patients with well-developed infarcts have shown dimin-

ished staining in necrotic regions [14,15].

2. Materials and methods

2.1. Tissues

We reviewed our log books of experiments performed

from 1979 to 1997 to identify animal experiments in which

well-characterized myocardial injury was produced in open

and closed chest models of myocardial ischemia. These

consisted of archival formalin-fixed, paraffin-embedded

myocardium from 50 experimental animals (dogs, pigs

and rats) that had undergone permanent coronary occlusion

(n = 34) for 0.5–6 h or occlusion of 0.75–6 h followed by

reperfusion (n = 16). Ischemic injury was characterized by a

number of methods including EM, PAS staining for gly-

cogen loss, and TTC staining and evaluation of H&E-

stained sections to demonstrate myocardial necrosis. In

studies in larger animals, alternate gross slices of myocar-

dium (slices 1, 3 and 5) were stained with TTC and

sampled for histologic evaluation (H&E stain) from TTC

positive and negative regions. Adjacent surfaces from slices

2 and 4 were sampled and processed for EM and PAS

staining. This protocol allowed comparison of staining for

troponins with ultrastructural and histochemical findings in

the same regions of myocardium. The experimental meth-

ods of producing myocardial ischemia and evaluating the

myocardial ischemic injury have been described in detail

[8–11,16–18]. All experiments were done in compliance

with institutional and national research council guidelines

for the care and use of laboratory animals. All animals were

sacrificed with an overdose of intravenous KCl.

We identified 50 animal experiments to restudy. These

50 cases were selected from 145 studies reviewed, because

they provided a range of coronary occlusion from 0.5 to

6.0 h, and there was adequate paraffin-embedded tissue

remaining to perform immunohistochemical studies. The

archival paraffin blocks were retrieved and recut. One H&E-

stained section of each block was prepared and examined

for histologic evidence of myocardial ischemia/necrosis.

Necrosis was defined as hypereosinophilia of myocytes

with or without contraction bands, with surrounding edema.

In many of the cases, there were varying degrees of

neutrophilic infiltrate in the necrotic regions. Some sections

showed only edema and wavy fibers and only subtle hyper-

eosinophilia of fibers [19]. These regions were judged not to

show definite histologic evidence of necrosis; however, our

previous EM studies had demonstrated necrosis in these

regions. Numerous unstained slides were prepared from

each paraffin block for immunohistochemical staining.

2.2. Immunohistochemical staining

All tissues used for immunohistochemical studies came

from transverse slices of myocardium fixed in 10%

neutral-buffered formalin for 24–36 h, processed routinely

and embedded in paraffin. Four-micron-thick tissue sec-

tions were deparaffinized in xylene for 5 min. Slides were

rehydrated in graded alcohols. Endogenous peroxidase

Table 1

Troponin loss with permanent occlusion

Duration of

occlusion

Degree of

troponin loss

(0 to � 3)

Histologic

evidence

of necrosis

Species Hours n Scorea Mean n

Dogs 0.5 6 � 1 to� 3 � 2.0 3 of 6

0.75 5 � 1 to� 3 � 1.4 1 of 5

3.0 3 � 1 to� 3 � 1.7 3 of 3

5.0 1 � 3 – 1 of 1

6.0 10 � 1 to� 3 � 2.3 10 of 10

Pigs 4.0 5 � 1 to� 3 � 2.6 5 of 5

Rats 1.0 2 � 3 � 3.0 0 of 2

3.0 1 � 3 – 0 of 1

0.0b 1 0 – 0 of 1

a Maximum score for any antibody tested from center or periphery

of infarct.b Sham-operated positive control.

M.C. Fishbein et al. / Cardiovascular Pathology 12 (2003) 65–7166

activity was inhibited by incubation in 3% hydrogen

peroxidase in methanol for 15 min followed by two 5-min

washes in phosphate-buffered saline (PBS). Sections were

then incubated for 30 min with 3% normal horse serum

(NHS, diluted with PBS) and then incubated for 1.5–2 h

with primary antibodies: cTnI 3302 (1:200), cTnI 3350-1D

(1:50), cTnI 3350-2F (1:100) and cTnT (1:100). After

removal of the primary antibodies with three 5-min

washes in PBS, sections were incubated for 40 min with

biotinylated horse antimouse IgG (Vector) diluted 1:200 in

1% NHS. After three 5-min washes in PBS, sections were

incubated for 30 min with horseradish peroxidase avidin D

(HRP, Vector) diluted 1:1000 with PBS. After three 5-min

washes of PBS, the sections were developed with DAB kit

(Vector), stopped with rinses of double-distilled water.

Slides were counterstained with dilute hematoxylin, rinsed

with ammonia and then with tap water. Sections were

dehydrated with graded ethanol, cleared in xylene and

then coverslipped.

The 33-2 (IgG1), 3350-ID (IgG1) and 3350-2F (IgG2A)

mouse antihuman cTnI antibodies were produced for West-

ern blot assays by Main Biotechnology Services and kindly

Fig. 1. (a–c) Sections of left ventricle from dog with 6 h of coronary occlusion without reperfusion. (a) Note edema and hypereosinophilia of myocytes in zone

of necrosis (asterisk) (H&E, � 12); (b) immunostaining for troponin I showing decreased staining of necrotic myocardium; and (c) higher power (� 60)

showing cell to cell variation in staining intensity. (d– f) Sections of left ventricle from dog with 1 h of occlusion and 3 h of reperfusion. (d) Note

hypereosinophilia of myocytes in the zone of necrosis (asterisk) (H&E, � 12); (e) immunostaining for troponin T showing accentuation of loss of troponin at

the edge of the infarct (arrows); (f) higher power (� 60) showing cell to cell variation in staining intensity.

M.C. Fishbein et al. / Cardiovascular Pathology 12 (2003) 65–71 67

donated to us by Jack Ladenson, PhD at Washington

University School of Medicine in St. Louis. All three

antibodies are directed against the N terminus cTnI region.

We used these three antibodies available to us to evaluate if

they were equal in sensitivity and specificity for detecting

cTnI loss from necrotic myocardium. We also wished to

determine if they differed in cross-reactivity to cardiac cTnI

from myocardium of species other than human beings. The

cTnT antiserum was purchased from Neomarkers (Fremont,

CA). Antibody dilutions and incubation times were chosen

to optimize staining of tissues.

Positive control slides came from a sham-operated rat

heart. Negative control slides consisted of animal tissues

with smooth muscle and skeletal muscle but no cardiac

muscle. A positive and negative control slide were stained

every time immunohistochemical staining was done. In

addition, each slide had its own built in negative and

positive controls: arteries within the myocardium were

expected to be negative for cTnT and cTnI, and nonischemic

regions of myocardium were expected to be positive. Strong

positive staining in the nonischemic regions also showed

that the integrity of the tissue antigenicity was preserved,

even in tissues stored up to 20 years in paraffin blocks. An

additional negative control for our staining procedure con-

sisted of replacing the primary antisera with saline.

Each immunostained slide was reviewed by two observ-

ers. Foci of ischemic injury were divided into peripheral and

central regions. The peripheral region consisted of several

Fig. 2. (a, b) Sections of left ventricle from dog sacrificed after 45 min of coronary occlusion. (a) Note only patches of hypereosinophilic, necrotic myocardium

(asterisks) (H&E, � 30); (b) loss of troponin I is visible in these regions of myocyte necrosis (asterisks). (c, d) Sections of left ventricular papillary muscle from

rat sacrificed after 3 h of coronary occlusion. (c) There is very subtle hypereosinophilia of necrotic myocytes (asterisk) (H&E, � 12) and (d) immunostaining

for troponin I showing decreased but variable staining of myocytes within the zone of necrosis (asterisk).


layers of myocytes immediately adjacent to viable myocar-

dium. The central region consisted of the remaining myo-

cardium within the ischemic zone. Loss of cardiac troponin

staining was scored for each region from 0 to � 3: 0 = no

loss of staining; � 1 =minimal decrease in staining, com-

pared to normally stained tissue; � 2 = clear decrease in

staining with some positivity (brown color) remaining; and

� 3 = no positive (brown) staining. The grade was based on

the maximum loss of cardiac troponin noted in the region.

3. Results

Permanent occlusion (no reperfusion) (Table 1): There

were 34 animals that had undergone permanent occlusions:

25 dogs with occlusions from 0.5 to 6 h; 5 pigs with 4-h

occlusions; and 3 rats, 2 with 1-h occlusion and 1 with a

3-h occlusion.

In all dogs with occlusions ranging from 0.5 to 6 h, if

there was histologic evidence of necrosis, there was some

loss of cTnT and cTnI from the tissue (Figs. 1 and 2). In

general, cTnT loss was more prominent than loss of cTnI

and, for all antisera, loss of troponin tended to be greater at

the periphery of the regions than at their centers. Two dogs

with 30-min occlusions and no histologic evidence of

necrosis showed no loss (score = 0) of cTnI (with all three

antibodies), but loss of cTnT (score =� 2). In three dogs

with 45-min occlusions and no histologic evidence of

necrosis (normal or edema only), all four antisera studied

demonstrated mild loss of cTnT and cTnI (score =� 1). In

all of these, dogs with brief periods of occlusion tissues

from the ischemic zone sampled for EM showed ultrastruc-

tural evidence of necrosis. Myocardium outside of the area

at risk showed no troponin loss and no morphologic

evidence of necrosis.

Four pigs each had 4 h of coronary occlusion accom-

panied by histologic evidence of myocardial necrosis. Three

had at least focal complete loss of cTnI and cTnT

(score =� 3); one had only mild loss (score =� 1).

Of the three rat hearts studied with 1 or 3 h of occlusion,

all had histologic evidence of myocardial edema. In addi-

tion, two had very subtle hypereosinophilia of myocytes.

These two showed focal marked loss of cTnI and cTnT

(score =� 3). One rat heart with a 1-h occlusion that had no

histologic evidence of necrosis showed no loss of either

cTnT or cTnI. Ultrastructural studies were not performed in

the rat hearts.

To summarize the findings with permanent occlusion,

all antibodies could detect both cTnT and cTnI in normal

myocardium and their loss in necrotic myocardium. Most

of the time, there was greater loss at the periphery than at

the center of the lesions; however, in all cases, the loss

was nonuniform in that some fibers showed complete loss

(score =� 3) with other fibers having varying degrees of

incomplete loss. Some fibers clearly within the necrotic

zone stained normally (score = 0). Usually, loss of cTnT

appeared to be greater than and appeared earlier than, loss

of cTnI. All three antibodies to cTnI gave similar results.

In some animals, primarily those with relatively brief

coronary occlusion (30–45 min) and ultrastructural evid-

ence of irreversible injury, loss of cardiac troponin stain-

ing could be identified even in the absence of histologic

proof of necrosis. The H&E-stained sections of these

slides showed only edema and, at most, subtle hyper-

eosinophilia. In our prior studies, EM evidence of nec-

rosis was present in the regions of troponin loss. No loss

of troponins was seen in myocardium that was viable by

H&E and TTC staining, and EM.

Occlusion followed by reperfusion (Table 2): In this

group, there were 10 dogs with occlusions of 0.75–6 h

followed by 15–30 min of reperfusion, and 6 pigs with 1 or

1.5 h of occlusion followed by 15 min of reperfusion. All of

these dogs and pigs had histologic evidence of myocardial

necrosis. All demonstrated at least focal loss of cardiac

troponins: 13 had a score of � 3, 1 had a score of � 2, and

2 had a score of � 1. As with animals with permanent

occlusion, there appeared to be more loss of cTnT than

cTnI. However, the marked difference observed between the

center and periphery of infarction in the group was much

more striking. The loss of staining at the periphery was

much greater than the loss observed in the center of the

infarct after reperfusion compared to permanent occlusion

(see Figs. 1 and 2). No loss of troponins was seen in

myocardium that was viable by H&E and TTC staining,

and EM.

4. Discussion

There have been a number of studies in a variety of

experimental models indicating that measurement of cardiac

troponins in serum might be useful for the diagnosis of

myocardial necrosis. O’Brien et al. showed that in both dog

and rat models of myocardial infarction, serum elevations of

cTnT were highly correlated with infarct size, 3 h after

occlusion. Further, using several animal species (dog, rat,

mouse and ferret), these authors showed that serum cTnT

Table 2

Troponin loss with occlusion followed by reperfusion

Duration

of occlusion

before reperfusiona

Degree of

troponin loss

(0 to � 3)

Histologic

evidence

of necrosis

Species Hours n Scorea Mean n

Dogs 0.75 1 � 3 – 1 of 1

1.0 3 � 3 � 3.0 3 of 3

2.0 4 � 2 to� 3 � 2.8 4 of 4

3.0 1 � 3 – 1 of 1

6.0 1 � 1 – 1 of 1

Pigs 1.0 5 � 1 to� 3 � 2.6 5 of 5

1.5 1 � 3 � 1 of 1

a Maximum score from center or periphery of infarct.


was a useful biomarker to detect myocardial injury associ-

ated with doxorubicin and trauma, as well as ischemic injury

[20]. Furthermore, Ricchiuti et al. [21] demonstrated that in

dogs with experimental myocardial infarction, increases in

serum troponins occurred in parallel with loss of troponins

from the ischemic myocardium. In rats, alterations in cTnT

and cTnI occurred with severe left ventricular remodeling

[22] and after prolonged intense exercise [23]. Direct

measurement of cTnT and cTnI in dogs, goats, cows, sheep,

horses, rabbits, turkeys, chicken and fish have confirmed

tissue reactivity of varying degrees indicating that elevations

in the blood would serve as useful biomarkers of myocardial

injury in many animal species [24,25]. Directly relevant to

man, Voss et al. [26] showed a 35–50% loss of cytosolic

myofibrillar cTnT in human myocardium from three patients

who died after myocardial infarction. All of the above

studies were biochemical rather than morphologic. None

examined the tissue microscopically to visualize the pattern

of cardiac troponin loss from the injured myocardium.

Initial observations suggest that cardiac troponin immu-

nostaining might be useful for identifying myocardial

necrosis in human autopsy hearts [14,15]. Our study, in

well-characterized animal models of myocardial infarction,

demonstrates that loss of tissue cTnT and cTnI can be seen

in infarcts only 30 min old, even before histologic evidence

of necrosis is apparent. It is well known that while EM can

detect necrotic myocytes 15–20 min after occlusion, histo-

logic changes take longer to evolve, often several hours

[27]. Thus, our studies indicate that immunohistochemical

staining for cTnI and cTnT may be more sensitive than

routine H&E staining for the recognition of myocardial

necrosis in experimental animals and human hearts at

autopsy. In addition, our study demonstrates that all of the

antibodies to human cardiac troponins we used cross-react

with canine, porcine and rodent cTnT and cTnI and can

therefore be applied to experimental animal studies of

myocardial ischemia.

In this study, we were not able to precisely map entire

regions that were proven to be ischemic, but not necrotic.

However, whenever we did observe loss of staining, there

was histologic or ultrastructural evidence of irreversibly

injured myocytes in the tissue. In the dog studies, we had

performed ultrastructural studies on samples of tissue within

the zone at risk of ischemic injury. In regions of myocar-

dium that did not demonstrate irreversible injury by EM, we

did not observe decreased staining for troponins.

We observed greater loss of cardiac troponin at the

periphery of an infarct than at its center. This likely reflects

greater antegrade and retrograde flow at the periphery with

‘‘washout’’ of proteins from the necrotic myocardium [28].

There was accentuation of this phenomenon with reperfu-

sion. Since reflow is known to be associated with the

‘‘washout phenomenon,’’ and greater, earlier blood pro-

tein/enzyme elevations in man, it is likely that the greater

loss of cardiac troponin seen at the periphery, especially

with reperfusion, represents a manifestation of this washout.

We observed heterogeneous loss of cTnT and cTnI in

necrotic myocardium. Even with relatively long periods of

occlusion (6 h), with or without reperfusion, there was a

great deal of variability of intensity of residual staining for

cardiac troponins within the necrotic region. There are

several explanations for this. First, since the distribution

of flow within the ischemic tissue is heterogeneous, necrosis

may evolve faster in some parts of the infarct than others.

Second, flow away from the necrotic fibers may also be

variable, resulting in different rates of ‘‘washout’’ from

different fibers. Since cell to cell variation in staining

occurred within small regions, as well as the entire infarcts,

these two mechanisms do not seem to explain the observed

findings. It is known that cardiac troponins are cleared from

the blood faster than CK-MB, but levels stay elevated

longer [29]. These observations suggest continued, delayed

release from the necrotic myocytes. We found substantial

positive staining of necrotic myocytes hours after coronary

occlusion in our experimental infarcts. This finding may

explain the observation in patients with myocardial infarcts

that cardiac troponin levels in the blood remain elevated for

several days, as opposed to CK-MB levels which return to

baseline more quickly. Our findings support the notion that

the sustained elevation of cardiac troponin in the blood,

days after coronary occlusion, is not the result of slow

elimination from the circulation, but rather, ongoing release

during infarct evolution. This persistent elevation in the

serum does not appear to be eliminated by reperfusion.

Concordant with the clinical observation, considerable posi-

tivity in necrotic myocardium persisted, even in animals

with coronary occlusion followed by reperfusion.

This study, as well as our previous studies of other

myocardial proteins in these models [7–11], indicate that

troponins are not lost from ischemic but nonnecrotic myo-

cardium. These findings are in concordance with the major-

ity of experimental work and clinical studies. Carlson et al.

[30] have reported that in patients undergoing dobutamine

stress echocardiography, stress-related reversible ischemia

was not accompanied by increased troponin levels in the

blood, even when using very sensitive methods and strin-

gent criteria. On the other hand, Venge et al. [31] have

shown that patients with unstable angina who do manifest

elevated c troponin in blood are at higher risk of adverse

outcome than those patients who do not. These patients who

presumably are experiencing episodes of myocardial nec-

rosis may benefit from more aggressive antithrombotic and

revascularization strategies. In our studies, we did not

sample blood for markers of necrosis; however, our mor-

phologic studies in well-characterized models of ischemic

injury support the concept that troponin release is specific

and sensitive for myocardial necrosis.

Lastly, in these studies, antibodies generated against

human cardiac troponins, stained normal rat, dog and pig

myocardium and were diminished in necrotic myocardium

in these animals. Thus, these antibodies should be useful in

experimental studies of myocardial ischemic injury in a


variety of animal models. The ability to detect loss of

cardiac troponins so early in the evolution of myocardial

necrosis also suggests a role for immunohistochemical

studies for cardiac troponins in human autopsies. Such

studies might assist pathologists in the recognition and

verification of myocardial infarction at autopsy, which has

been a challenge for pathologists to date. In this regard, a

preliminary report appears encouraging [14].

Acknowledgments

The authors are grateful to Dr. Jack Ladenson for

donating antisera to troponin I. The authors also wish to

recognize the expert secretarial assistance and word

processing skills of Ms. Judy Wiltz and the photographic

expertise of Ms. Carol Appleton. This study was support-

ed by a generous endowment from the Piansky Family

Trust (MCF).

References

[1] Jaffe AS, Ravkilde J, Roberts R, Naslund U, Apple FS, Galvani M,

Katus H. Its time for a change to a troponin standard. Circulation

2000;102:1216–20.

[2] Antman EM, Tanasijevic MJ, Thompson B, Schactman M,

McCabe CH, Cannon CP, Fischer GA, Fung AY, Thompson C,

Wybenga D, Braunwald E. Cardiac-specific troponin I levels to

predict the risk of mortality in patients with acute coronary syn-

dromes. N Engl J Med 1996;335:1342–9.

[3] Ohman ME, Armstrong PW, Christenson RH, Granger CB, Katus HA,

Hamm W, O’Hanesian MA, Wagner GS, Kleiman NS, Harrell FE,

Califf RM, Topol EJ. Cardiac troponin T levels for risk stratification in

acute myocardial ischemia. N Engl J Med 1996;335:1333–41.

[4] Apple FS, Falahati A, Paulson PR, Miller E, Sharkey SW. Improved

detection of minor ischemic myocardial injury with measurement of

serum cardiac troponin I. Clin Chem 1997;43:2047–51.

[5] Giannitsis E, Muller-Bardorff M, Lehrke S, Wiegand U, Tolg R,

Weidtmann B, Hartmann F, Richardt G, Katus HA. Admission tro-

ponin T level predicts clinical outcome, TIMI flow, and myocardial

tissue perfusion after primary percutaneous intervention for acute

ST-segment elevation myocardial infarction. Circulation 2001;104:

630–5.

[6] Alpert JS, Thygesen K, Antman E, Bassand JP. Myocardial infarction

redefined—a consensus of the Joint European Society of Cardiology/

American College of Cardiology Committee for the Redefinition of

Myocardial Infarction. J Am Coll Cardiol 2000;36:959–69.

[7] Moran MM, Siegel RJ, Said JW, Fishbein MC. Demonstration of

myoglobin CK-M in myocardium. J Histochem Cytochem 1985;33:

1110–5.

[8] Siegel RJ, Said JW, Shell WE, Corson G, Fishbein MC. Identification

and localization of creatine kinase B and M in normal, ischemic and

necrotic myocardium: an immunohistochemical study. J Mol Coll

Cardiol 1984;16:95–103.

[9] Block MI, Said JW, Siegel RJ, Fishbein MC. Myocardial myoglobin

following coronary artery occlusion: an immunohistochemical study.

Am J Pathol 1983;111:374–9.

[10] Herscher LL, Siegel RJ, Said JW, Edwalds LL, Moran MM, Fishbein

MC. Distribution of LDH-1 in normal, ischemic, and necrotic myo-

cardium. Am J Clin Pathol 1984;81:198–203.

[11] Siegel RJ, Edwalds G, Rej R, Fishbein MC. Distribution of cytosolic

and mitochondrial aspartate aminotransferase in normal, ischemic, and

necrotic myocardium: an immunohistochemical study. Lab Invest

1984;51:648.

[12] Edwalds GM, Said JW, Block MI, Herscher LL, Siegel RJ, Fishbein

MC. Myocytolysis (vacuolar degeneration) of myocardium: immuno-

histochemical evidence of viability. Hum Pathol 1984;15:753–6.

[13] FishbeinMC,Meerbaum S, Rit J, LandoU, Kanmatsuse K,Mercier JC,

Corday E, Ganz W. Early phase acute myocardial infarct size quantifi-

cation: validation of the triphenyl tetrazolium chloride tissue enzyme

staining technique. Am Heart J 1981;101:593–600.

[14] Hansen SH, Rossen K. Evaluation of cardiac troponin I immunoreac-

tion in autopsy hearts: a possible marker of early myocardial infarc-

tion. Forensic Sci Int 1999;99:189–96.

[15] Lambie WK, Afify AM. Immunohistochemical evaluation of recent

myocardial infarction using troponin I, troponin T, and complement 9.

Lab Invest 2002;82:6A.

[16] Hatori N, Tadokoro H, Satomura K, Miyazaki A, Fishbein MC,

Ryden L, Corday E, Drury JK. Beneficial effects of coronary venous

retroinfusion but not left atrial administration of superoxide dismu-

tase on myocardial necrosis in pigs. Eur Heart J 1991;12:442–50.

[17] HatoriN,RobertsRL, TadokoroH,RydenL, SatomuraK, FishbeinMC,

Stiehm ER, Corday E, Drury JK. Differences of infarct size with

lidocaine as compared with bretylium tosylate in acute myocardial

ischemia and reperfusion in pig. J Cardiol Pharm 1991;18:581–8.

[18] McElroy CL, Gissen SA, Fishbein MC. Exercise-induced reduction in

myocardial infarct size after coronary artery occlusion in the rat. Cir-

culation 1978;57:5.

[19] Bouchardy B, Majno G. Histopathology of early myocardial infarcts.

Am J Pathol 1974;74:301–30.

[20] O’Brien PJ, Dameron GW, Beck ML, Kang YJ, Erickson BK, Di

Battista TH, Miller KE, Jackson KN, Mittelstadt S. Cardiac troponin

T is a sensitive specific biomarker of cardiac injury in laboratory

animals. Lab Anim Sci 1997;47:5.

[21] Ricchiuti V, Sharkey SW, Murakami MM, Voss EM, Apple FS. Car-

diac troponin I and T alterations in dog hearts with myocardial in-

farction. Am J Clin Pathol 1998;110:241–7.

[22] Ricchiuti V, Zhang J, Apple FS. Cardiac troponin I and T alterations in

hearts with severe left ventricular remodeling. Clin Chem 1997;43–

46:990–5.

[23] Chen Y, Serfass RC, Mackey-Bojack S, Kelly KL, Titus JL, Apple

FS. Cardiac troponin T alterations in myocardium and serum of rats

after stressful, prolonged intense exercise. J Appl Physiol 2000;88:

1949–55.

[24] O’Brien PJ, Dameron GW, Beck ML, Brandt M. Differential reactivity

of cardiac and skeletal muscle from various species in two generations

of cardiac troponin T immunoassays. Res Vet Sci 1998;65:135–7.

[25] O’Brien PJ, Landt Y, Ladenson JH. Differential reactivity of cardiac

and skeletal muscle from various species in a cardiac troponin I im-

munoassay. Clin Chem 1997;43:2333–8.

[26] Voss EM, Sharkey SW, Gernert AE, Murakami MM, Johnston RB,

Hsieh CC, Apple FS. Human and canine cardiac troponin T and

creatine kinase-MB distribution in normal and diseased myocardium:

infarct sizing using serum profiles. Arch Pathol Lab Med 1995;119.

[27] Jennings RB, Ganote CE. Structural changes in myocardium during

acute ischemia. Circ Res 1974;34–35(suppl III):156–72.

[28] Fishbein MC. Reperfusion injury. Clin Cardiol 1990;13:213–7.

[29] Katus HA, Remppis A, Scheffold T, Diederich KW, Kuebler W. Intra-

cellular compartmentation of cardiac troponin T and its release ki-

netics in patients with reperfused and nonreperfused myocardial

infarction. Am J Cardiol 1991;67:1360–7.

[30] Carlson RJ, Navone A, McConnell JP, Burritt M, Castle MC, Grill D,

Jaffe AS. Effect of myocardial ischemia on cardiac troponin I and T.

Am J Cardiol 2002;89:224–6.

[31] Venge P, Lagerqvist B, Diderholm E, Lindahl B, Wallentin L. Clinical

performance of three cardiac troponin assays in patients with unstable

coronary artery disease (a FRISC II substudy). Am J Cardiol 2002;

89:1035–41.


Myocardial tissue troponins T and I

Documents

Transcript of Myocardial tissue troponins T and I