Immunohistochemical study of fibronectin for postmortem diagnosis of early myocardial infarction

Postmortem Immunohistochemical Findings in Early Acute Myocardial Infarction: A Systematic Review

The diagnosis of early acute myocardial infarction is of particular importance in forensic practice considering the frequency of sudden cardiac death and the difficulty of positively identifying it through classical histological methods if survival is less than 6 h. This article aims to analyze potential immunohistochemical markers that could be useful in diagnosing acute myocardial infarction within the first 6 h of its onset. We conducted an extensive evaluation of the literature according to the PRISMA guidelines for reporting systematic literature reviews. We searched the Web of Science and PubMed databases from their inception to 2023 using the following keywords: "myocardial infarction" and "immunohistochemistry". Fifteen studies met the inclusion criteria. Immunohistochemical markers as complement factors and CD59, myoglobin, fibrinogen, desmin, tumor necrosis factor alpha (TNF-α), P-38, JNK (Jun N Terminal Kinase), transforming growth factor β1 (TGF-β1), cardiac troponins, fibronectin, H-FABP (heart fatty acid binding protein), dityrosine, fibronectin, CD15, IL-1β, IL-6, IL-15, IL-8, MCP-1, ICAM-1, CD18, and tryptase can be used to identify the first six hours of acute myocardial infarction. These markers are mostly studied in experimental animal models. It is necessary to conduct extensive studies on human myocardial tissue fragments, which will involve the analysis of several immunohistochemical markers and careful analysis of the available data on perimortem events, resuscitation, and postmortem intervals in the context of a uniform laboratory methodology.

Forensic significance of intracardiac expressions of Nrf2 in acute myocardial ischemia

When exposed to oxidative and electrophilic stress, a protective antioxidant response is initiated by nuclear factor erythroid 2-related factor 2 (Nrf2). However, the extent of its importance in the forensic diagnosis of acute ischemic heart diseases (AIHD), such as myocardial infarction (MI), remains uncertain. On the other hand, immunohistochemical analyses of fibronectin (FN) and the terminal complement complex (C5b-9) prove valuable in identifying myocardial ischemia that precedes necrosis during the postmortem diagnosis of sudden cardiac death (SCD). In this study, we investigated the immunohistochemical levels of Nrf2, FN, and C5b-9 in human cardiac samples to explore their forensic relevance for the identification of acute cardiac ischemia. Heart samples were obtained from 25 AIHD cases and 39 non-AIHD cases as controls. Nrf2 was localized in the nuclei of cardiomyocytes, while FN and C5b-9 were detected in the myocardial cytoplasm. The number of intranuclear Nrf2 positive signals in cardiomyocytes increased in AIHD cases compared to control cases. Additionally, the grading of positive portions of cardiac FN and C5b-9 in the myocardium was also significantly enhanced in AIHD, compared to controls. Collectively, these results indicate that the immunohistochemical investigation of Nrf2 combined with FN, and/or C5b-9 holds the potential for identifying early-stage myocardial ischemic lesions in cases of SCD.

Pathological Aspects and Immunohistochemical Evaluation of Troponin C in the Cardiovascular System of Dogs with Pheochromocytoma

Functional pheochromocytomas secrete catecholamines and have been associated with cardiovascular lesions in dogs. This study aimed to describe the post-mortem pathological findings in the cardiovascular system of dogs with pheochromocytoma and to evaluate the expression of cardiac troponin C in these dogs using immunohistochemical analysis. Twelve cases were identified, with a mean age of 10.6 years. The heart of all dogs was enlarged and with concentric hypertrophy of the left ventricular myocardium. Histological analysis showed cardiomyocyte necrosis and degeneration in the myocardium, with frequent bands of contraction, fibrosis, inflammation, and thickening of the medium-calibre arteries in the myocardium. There was a marked decrease or absence of immunolabeling in necrotic cardiomyocytes. We conclude that IHC for troponin C can be a useful tool for detecting myocardial necrosis in dogs with pheochromocytomas, including early cases of necrosis with only incipient cardiac changes where overt histologic abnormalities are not immediately apparent in the cardiomyocytes.

Cardiomyocytes calpain 2 expression: Diagnostic forensic marker for sudden cardiac death caused by early myocardial ischemia and an indicator of the duration of myocardial agonal period?

Sudden cardiac death (SCD) is an unexpected natural death of cardiac etiology and occurs within one hour of the onset of cardiac symptoms in an apparently healthy subject or within 24 h if death is not witnessed. The diagnosis of early myocardial ischemia (EMI) or acute myocardial infarction (AMI) after death is a challenge for forensic pathologists especially when death occurs in a short period of time after the onset of myocardial ischemia. Disorder of cardiomyocytes Ca2+ homeostasis caused by myocardial ischemia during SCD can lead to the activation of calcium-activated non-lysosomal cysteine protease, including calpains. They serve as a proteolytic unit for cell balance and also participate in the processes of apoptosis and necrosis. Agony is a period that precedes somatic death that differs from cellular agony which may evolve for hours after somatic death lasting differently depending on the cell type and mechanism of death. We hypothesize that the expression of calpain 2 in cardiomyocytes could be a specific and sensitive diagnostic forensic marker for SCD caused by EMI and an indicator of the duration of myocardial agonal period. We will conduct a retrospective study that will prove this hypothesis on the respondents who died of SCD by EMI and AMI, instant death by head gunshot and hanging. There is no data on such an analysis in the available literature. The standard hematoxylin-eosin staining will be used to detect cardiac tissue damage. The expression of calpain 2 in cardiomyocytes will be analyzed immunohistochemically. In SCD caused by EMI we expect lower level of calpain 2 expressionin comparison to AMI due to shorter duration of dying. Similar, we predict in the remote region lower calpain 2 expression than in the region of ischemia for both EMI and AMI. In instant death caused by perforating traumatic brain injury we expect mild or no calpain 2 expression throughout the whole myocardium because of very short (immediate) duration of dying. In death caused by hanging calpain 2 expression throughout the whole myocardium should be strong because of longer cellular agonal period. We expect that our results would indicate the immediate activation of calpain 2 in different causes of cardiomyocytes death. From the degree of expression of calpain 2 we could conclude about the duration of cardiomyocytes agony so calpain 2 could be used as a marker for the assessment the duration of somatic and cellular agony.

Forensic significance of intracardiac heme oxygenase-1 expression in acute myocardial ischemia

Heme oxygenase-1 (HO-1), an inducible stress-response protein, exerts anti-oxidant and anti-apoptotic effects. However, its significance in forensic diagnosis of acute ischemic heart diseases (AIHD) such as myocardial infarction (MI) is still unknown. We examined the immunohistochemical expression of HO-1 in the heart samples to discuss their forensic significance to determine acute cardiac ischemia. The heart samples were obtained from 23 AIHD cases and 33 non-AIHD cases as controls. HO-1 positive signals in cardiomyocyte nuclear were detected in 78.2% of AIHD cases, however, that were detected in only 24.2% control cases with statistical difference between AIHD and non-AIHD groups. In contrast to HO-1 protein expression, there was no significant difference in the appearance of myoglobin pallor regions and leukocyte infiltration in the hearts between AIHD and non-AIHD groups. From the viewpoints of forensic pathology, intracardiac HO-1 expression would be considered a valuable marker to diagnose AIHD as the cause of death.

Sequence and time course of depletion of cardiac cellular proteins and accumulation of plasma proteins in rat early ischemic myocardium

In order to investigate the sequence and time course of fibronectin (Fn), fibrinogen (Fg), complement (C5), myoglobin (Mb), actin (HHF35), and desmin (Dm) for the diagnosis of early myocardial ischemia, the myocardial ischemia model was established in rats, the positive reaction areas of Fn, Fg and C5 and the depletion areas of Mb, HHF35 and Dm in the ischemic cardiomyocytes were studied with immunohistochemistry, image analysis technique and statistical system. The results showed that the depletion of Dm, HHF35 and Mb, and the positive staining of Fg and C5 in ischemic cardiomyocytes were found as early as 15 min after the myocardial ischemia, but the positive staining of Fn occurred till 3 h after myocardial ischemia. With the prolongation of ischemia, the areas of the depletion of Dm, HHF35, Mb and the positive staining of Fg, C5 and Fn gradually enlarged. It is suggested that all the six immunohistochemical markers are more sensitive than routine H&E staining, and that Dm, HHF35, Mb, Fg, C5 are more sensitive markers than Fn for detection of early myocardial ischemia.

Diagnosis of sudden cardiac death due to early myocardial ischemia: An ultrastructural and immunohistochemical study

The aim of this post-mortem ultrastructural and immunohistochemical study is to explore the characteristics of acute myocardial ischemia in the context of sudden death, using the combination of two different methods, both more insightful than ordinary histology. Transmission electron microscopy and immunohistochemistry, in addition to the traditional histology, were applied to study human heart specimens collected during forensic autopsies. The whole series was sub-grouped into cases (n=17) and controls (N=10). The control group consisted of unnatural death with a short agonal period (immediately lethal injuries). Heart samples of the two cohorts of subjects were prepared for electron microscopy. On the other hand, each specimen, formalin fixed and paraffin embedded, was stained with haematoxylin and eosin and immunoreacted with the following primary antibodies: anti-Fibronectin, anti- Connexin-43, anti-npCx43 (dephosphorylated form of Connexin43), anti-Zonula occludens-1. Immunopositivity for each marker in the myocardium was semi-quantitatively graded. Electron microscopy revealed a number of interesting differences, statistically significant, between acute myocardial ischemia and controls, regarding the morphology of nucleus, mitochondria and intercellular junctions. By immunohistochemistry, fibronectin was found to be increased in the extracellular matrix of the acute myocardial ischemia cases, with a statistically significant difference compared to the controls. Connexin 43 staining disclosed a slight increase (not statistically significant) in the cytoplasm of acute myocardial ischemia cases compared to the controls, whereas no significant differences were seen between cases and controls at intercellular junctions. npCx43 showed an evident difference of intensity and pattern (even though not statistically significant) in cases compared to controls and overall this difference was more evident in the cytoplasm. Zonula occludens 1, described as an important marker for functional modification of cardiac muscle fibers, resulted negative or very weak in the vast majority of both cases and controls. The present study attempts to simultaneously apply electron microscopy and immunohistochemistry, in order to figure out the morphological changes that might lead to pathological processes underlying the sudden, unexpected death due to acute myocardial ischemia, and consequently to find useful diagnostic markers of very early ischemic injury. Both methods showed significant differences between acute myocardial ischemia and controls, regarding, overall nuclei, mitochondria, and intercellular junctions.

Early markers of myocardial ischemia: from the experimental model to forensic pathology cases of sudden cardiac death

The goal of this study was to assess whether early markers of myocardial ischemia, identified in a previous experimental work, can be applied in forensic pathology cases of sudden, ischemic cardiac death. These markers include desphosphorylated connexin 43 (Cx43), JunB, TUNEL assay, myoglobin, and troponin T. Fourteen cases of sudden cardiac death with gross and/or histological signs of myocardial infarction and 14 cases of sudden cardiac death with signs of early ischemia at histology and positive immunoreactions for fibronectin and C5b-9 were investigated. The control group was represented by 15 hanging (global hypoxia) cases. Immunohistochemical reactions were classified into four degrees and compared among groups. Cx43 and JunB were significantly more expressed in hanging than in ischemia/infarction, but they showed a different distribution in the tissue (sub-endocardial in ischemia/infarction, diffuse in hanging) and a different intensity of the signal. TUNEL assay was significantly more expressed in the group of early ischemia than in myocardial infarction. Myoglobin and troponin T did not show any significantly different expression among the three groups. Depletion markers have a limited application in forensic cases, and this is mostly because positive (depleted) areas are difficult to distinguish from artifactually paler areas. Nuclear markers (JunB and TUNEL), on the other hand, require a well-trained eye and a high magnification in order to be distinguished. Cx43, JunB, and TUNEL assays were confirmed to be early, sensitive markers for myocardial ischemia. Nonetheless, they are not specific, as they are expressed in global hypoxia as well, but with a different tissular distribution.

Early markers for myocardial ischemia and sudden cardiac death

The post-mortem diagnosis of acute myocardial ischemia remains a challenge for both clinical and forensic pathologists. We performed an experimental study (ligation of left anterior descending coronary artery in rats) in order to identify early markers of myocardial ischemia, to further apply to forensic and clinical pathology in cases of sudden cardiac death. Using immunohistochemistry, Western blots, and gene expression analyses, we investigated a number of markers, selected among those which are currently used in emergency departments to diagnose myocardial infarction and those which are under investigation in basic research and autopsy pathology studies on cardiovascular diseases. The study was performed on 44 adult male Lewis rats, assigned to three experimental groups: control, sham-operated, and operated. The durations of ischemia ranged between 5 min and 24 h. The investigated markers were troponins I and T, myoglobin, fibronectin, C5b-9, connexin 43 (dephosphorylated), JunB, cytochrome c, and TUNEL staining. The earliest expressions (≤30 min) were observed for connexin 43, JunB, and cytochrome c, followed by fibronectin (≤1 h), myoglobin (≤1 h), troponins I and T (≤1 h), TUNEL (≤1 h), and C5b-9 (≤2 h). By this investigation, we identified a panel of true early markers of myocardial ischemia and delineated their temporal evolution in expression by employing new technologies for gene expression analysis, in addition to traditional and routine methods (such as histology and immunohistochemistry). Moreover, for the first time in the autopsy pathology field, we identified, by immunohistochemistry, two very early markers of myocardial ischemia: dephosphorylated connexin 43 and JunB.

Immunohistochemical analysis of cardiac troponin inhibitor in an experimental model of acute myocardial infarction experimental model and in human tissues

Acute obstruction of coronary arteries leads to acute myocardial infarction (AMI), which causes unexpected death in humans. However, AMI cannot be easily detected in forensic examinations with traditional hematoxylin and eosin (H&E) staining. We analyzed whether cardiac troponin inhibitor (CTnI) could serve as a sensitive and specific early marker for diagnosing AMI in forensic medicine. We established an AMI model in rabbits by ligating the left ventricular branch and observed CTnI expression with immunohistochemistry after different ligation times. We found increased CTnI staining at the 0.5-h time point and depletion of CTnI staining with a 1-h ligation. The areas in which CTnI staining was depleted as seen with immunohistochemical analysis were consistent with the results of H&E staining. Next, human myocardium tissues from 30 persons who died from AMI and were subsequently examined in our forensic center were studied using immunohistochemistry with an antibody to human CTnI. Areas of infarction also showed depletion of CTnI staining. These findings suggested that immunohistochemical detection of CTnI is earlier, more sensitive, and myocardial tissue - specific as compared with H&E staining. CTnI may serve as an ideal marker for diagnosing AMI in forensic investigations.

Sudden cardiac death and myocardial ischemia indicators: a comparative study of four immunohistochemical markers

The postmortem diagnosis of acute myocardial infarction represents a current challenge for forensic pathologists, particularly when death occurs within minutes to a few hours after the ischemic insult. Among the adult population the single most important cause of sudden cardiac death (SCD) is the well-known atherosclerotic coronary artery disease, commonly asymptomatic or unrecognized. The recognition of early myocardial damage using routine hematoxylin and eosin (H&E) staining is possible only if death has occurred at least 6 hours after the onset of the ischemic injury. The usefulness of immunohistochemical markers to the diagnosis of early myocardial damage has been recently suggested because most of them can be visible even serologically as early as few minutes after the beginning of the symptoms. To evaluate the usefulness of plasma and cellular antigens, their distribution patterns have been studied among a group of 18 SCD cases in which a myocardial ischemia was strongly suspected. For the present study, 4 markers have been selected on the basis of their different diagnostic potential as follows: among the plasma markers the C5b-9 and fibronectin, among the cellular markers the myoglobin and cardiac troponin. The results show that only the study of multiple markers such as those selected can provide enough evidence of myocardial ischemia and/or necrosis, supporting the final diagnosis of SCD. No single immunohistochemical staining is ideal for diagnosing early myocardial ischemia but a set of markers can improve the ability of forensic pathologists to detect ischemic areas when no macroscopic or microscopic evidence of necrosis is available. However, the interpretation of data obtained in each individual cannot be isolated from the overall assessment of the factors (cardiopulmonary resuscitation and/or agonal artifacts) that can affect the expression of each marker.

Accumulation of fibronectin in the heart after myocardial infarction: a putative stimulator of adhesion and proliferation of adipose-derived stem cells

Stem cell therapy is a promising treatment after myocardial infarction (MI). A major problem in stem cell therapy, however, is that only a small proportion of stem cells applied to the heart can survive and differentiate into cardiomyocytes. We hypothesized that fibronectin in the heart after MI might positively affect stem cell adhesion and proliferation at the site of injury. Therefore, we investigated the kinetics of attachment and proliferation of adipose-tissue-derived stem cells (ASC) on fibronectin and analysed the time frame and localization of fibronectin accumulation in the human heart after MI. ASCs were seeded onto fibronectin-coated and uncoated culture wells. The numbers of adhering ASC were quantified after various incubation periods (5-30 min) by using DNA quantification assays. The proliferation of ASC was quantified after culturing ASC for various periods (0-9 days) by using DNA assays. Fibronectin accumulation after MI was quantified by immunohistochemical staining of heart sections from 35 patients, after different infarction periods (0-14 days old). We found that ASC attachment and proliferation on fibronectin-coated culture wells was significantly higher than on uncoated wells. Fibronectin deposition was significantly increased from 12 h to 14 days post-infarction, both in the infarction area and in the border-zone, compared with the uninfarcted heart. Our results suggest that a positive effect of fibronectin on stem cells in the heart can only be achieved when stem cell therapy is applied at least 12 h after MI, when the accumulation of fibronectin occurs in the infarcted heart.

Fatal trauma to the neck: immunohistochemical study of local injuries

As fatal trauma to the neck is often associated with short survival times, proof of vitality may often be difficult using standard histochemical techniques. Soft tissue neck injuries resulting from strangulation by ligature or manual strangulation were examined immunohistochemically using antibodies to myoglobin, fibronectin, C5b-9 and MRP14, and compared to controls consisting of accidental soft tissue neck injuries as well as undamaged neck soft tissue. Although survival times in the study and control groups were unknown and certainly some individual variation may be expected in the time course of normal wound development, both the study and control groups demonstrated similar time courses in the immunohistochemical detection of antigen. Myoglobin was always found in those samples in which only one antigen was shown to be involved in an injury-specific pattern; myoglobin and fibronectin were found in samples with dual antigen involvement. Samples involving three antigens always included C5b-9 in addition to myoglobin and fibronectin. The single positive MRP14 sample in the study and control groups was simultaneously positive for the other markers used. Myoglobin, fibronectin, C5b-9 and MRP14 are therefore suitable for immunohistochemical detection of vital reactions and estimation of temporal relationships in the early posttraumatic period after neck trauma.

The time-dependent expression of fibronectin, MRP8, MRP14 and defensin in surgically treated human skin wounds

Fibronectin, MRP8, MRP14 and defensin were detected immunohistochemically in 46 surgically treated, fresh (hours old) human wounds and in wounds of 13 individuals who died immediately from fatal trauma (airplane crashes or train rollovers). In immediate fatal trauma, it was not possible to detect fibronectin outside of bleeding areas nor could inflammatory cells be visualized in the interstitium using MRP8, MRP14, or defensin antibodies. Fibronectin staining could be regularly demonstrated in wounds at least 20 min-old. Granulocytic infiltrates limited to the perivasal space could be detected 20-30 min after infliction of the wound expressing MRP8, MRP14 and defensin. It was also possible to detect fibronectin networks and MRP8-, MRP14-, and defensin-positive granulocytes and macrophages in particular wounds up to 30 days-old. No differences between the expression of MRP8 and MRP14 could be demonstrated in the wounds, the majority of which were only several hours old. As wound age increased, the number of defensin-positive granulocytes detected decreased. The immunohistochemical detection of fibronectin is a useful way to demonstrate vitality in fresh wounds, beginning about 20-30 min post-trauma. However, detection of MRP8, MRP14 and defensin provides no advantage over the routine histological detection of granulocytes and macrophages in wounds under 1-2 days old.

Study on the specificity of fibronectin for post-mortem diagnosis of early myocardial infarction

In order to investigate the specificity of fibronectin (Fn) in the post-mortem diagnosis of myocardial infarction, the changes of Fn staining in normal, infarcted and other non-infarcted myocardial injuries resulting from myocarditis, mechanical asphyxia, electrocution, hemorrhagic shock, cardiac contusion and organophosphate poisoning were studied with an immunohistochemistry and image analysis system. The results showed that positive Fn staining could only be observed in groups of myocardial infarction and myocarditis, but could not be found in groups of mechanical asphyxia, electrocution, hemorrhagic shock, cardiac contusion, and organophosphate poisoning. Our findings indicate that positive staining of Fn in cardiomyocytes could be affected only by myocarditis, so it is quite specific for the diagnosis of myocardial infarction.

Is immunohistochemistry a useful tool in the postmortem recognition of myocardial hypoxia in human tissue with no morphological evidence of necrosis?

Myocytes in the border zone of myocardial infarction are under severe hypoxia without characteristic morphology of necrosis, and show ultrastructural features similar to those seen within the first hours after coronary occlusion. This study was carried out to evaluate the possibility that immunohistochemical methods could be used for the early diagnosis of myocardial infarction by detecting areas of hypoxia. Nineteen human sections of formalin-fixed paraffin-embedded myocardial samples showing a necrotic area and its border were submitted to immunohistochemical staining with the markers antimuscle actin, antimyoglobin, antitroponin T, antifibronectin, and anticomplement component C9. Sections were also subjected to azan trichrome and hematoxylin-basic fuchsin-picric (HBFP) staining techniques. Immunohistochemistry and azan trichrome showed that in the border zone there was a pattern of reaction intermediate between the infarcted area and the normal myocardium. The HBFP failed to distinguish these two areas. In conclusion, immunohistochemistry and azan trichrome can recognize myocardial hypoxia. Because hypoxia is an invariable condition in infarction, these techniques can be used to confirm suspected cases of myocardial infarction in which necrosis is not yet evident. However, considering that agonal states may be associated with generalized hypoxia, further studies are needed to confirm the reliability of this procedure in the earlier phases of myocardial infarction.

Primary study of vascular endothelial growth factor immunohistochemical staining in the diagnosis of early acute myocardial ischemia

The expression of vascular endothelial growth factor (VEGF) in the model of rat early acute myocardial ischemia was studied by Strept-Avidin-Biotin-Peroxidase Complex (SABC) immunohistochemical staining. After ligating the anterior descending branch of the left coronary artery, an initial rapid (30min) positive expression of VEGF in myocardial ischemic areas was observed, the intensity of positive expression of VEGF increased with the continuation of myocardial ischemia. After 5h infarction, the strongly positive myocytes of SABC-VEGF staining were predominantly limited to perimyocardial infarction areas. No positive expression of VEGF was found in the control group. These findings suggested that SABC-VEGF method could give a sensitive, specific, simple and objective morphologic evidence to the diagnosis of sudden cardiac death caused by acute early myocardial ischemia.

Sequential changes in localization of repair-related proteins (heat shock protein 70, ubiquitin and vascular endothelial growth factor) in the different stages of myocardial infarction

AIMS

The myocardium expresses vascular endothelial growth factor (VEGF), heat shock protein 70 (HSP70), and ubiquitin immediately after the onset of cardiac ischaemia. This study demonstrated the sequential changes in localization of these proteins, in addition to fibronectin and troponin T (TnT), in human hearts with myocardial infarction (MI).

METHODS AND RESULTS

Myocardial tissues from 40 autopsied MI cases were immunostained with the five antibodies against VEGF, HSP70, ubiquitin, fibronectin and TnT. Fibronectin was recognized only in the cardiomyocytes with infarction. Although TnT, HSP70, ubiquitin and VEGF were detected in the affected myocardium in the early stages, their expression in cardiomyocytes around infarcted foci were more intense. The cardiomyocytes with coagulative myocytolysis were positive for fibronectin, but negative or weakly positive for TnT, HSP70, ubiquitin and VEGF. In contrast, the cardiomyocytes with colliquative myocytolysis were strongly positive for TnT, HSP70, ubiquitin and VEGF, but negative for fibronectin.

CONCLUSIONS

Immunostaining using antibodies to fibronectin, TnT, HSP70, ubiquitin and VEGF is useful for the discrimination between infarcted myocytes and ischaemia-damaged myocytes in the human heart with MI at autopsy.

Clinico-pathologic, immunohistochemical, and TUNEL study in early cardiac allograft failure

Early cardiac allograft failure (ECAF) was defined as acute allograft failure in the early transplant period. The aim of this study is to elucidate the clinicopathological and immunohistochemical characteristics and the role of apoptosis in ECAF in nine patients. We reviewed preoperative clinical data and morphological data at the time of autopsy or retransplantation. We also performed TUNEL assay and immunohistochemistry to study fibronectin and tubulin beta-II. The average recipient and donor age was 48 +/- 10.3 and 28 +/- 7.11 respectively. Seven patients died at a mean time of 26 hours. The remaining two patients underwent retransplantation and are alive. The mean cold ischemic time was 124. 1 +/- 44.5 minutes. No patient had a panel reactive antibody >15% and lymphocytic crossmatch was positive in one case. All cases had grade 2-3 of coagulative necrosis, which correlated positively with fibonectin accumulation in myocyte cytoplasm, and cytoplasmic tubulin loss (p < 0.05). TUNEL technique showed in all cases some degree of DNA strand breaks in cardiomyocytes. Endothelium DNA strand breaks were seen in seven cases. Patients transplanted because of idiopathic dilated cardiomyopathy had a significantly higher degree of DNA strand breaks in cardiomyocytes and endothelial cells (p = 0.03 and p = 0.02) than those transplanted because of ischemic cardiomyopathy. These results indicate that ECAF may be caused by ischemic-reperfusion damage to the donor heart assessed by myocyte coagulative necrosis, fibronectin accumulation in myocytes, tubulin loss, and DNA strand breaks of cardiomyocytes and endothelium. The use of a combination of these techniques might be appropriate in the diagnosis of ECAF in endomyocardial biopsies when it is suspected clinically.

Evaluation of cardiac troponin I immunoreaction in autopsy hearts: a possible marker of early myocardial infarction

Postmortem diagnosis of early myocardial infarctions is an ever recurrent problem in pathology. In the present study we determined the troponin I expression in 46 autopsy hearts using an immunohistochemical technique. Troponin I has, as a specific cardiac muscle protein, become a widespread used marker in testing patients with acute chest pain. The hearts were divided into three groups based on the macroscopical findings: definite signs of infarction, possible signs of infarction and no signs of infarction. All 14 cases of definite myocardial infarction showed a well-defined area with loss of troponin I. Twenty-three of 24 cases of possible myocardial infarction also showed a well-defined area with loss of troponin I. None of the eight non-cardiac death controls showed loss of troponin I expression. The results suggest troponin I expression as a sensitive test in diagnosis of early myocardial infarction.

Immunohistochemical detection of fibronectin in postmortem incised wounds of porcine skin

Fibronectin plays an important role in tissue repair and wound healing. Previous literature reports indicated that fibronectin could be a marker of vitality for wounds with a survival time of more than a few minutes. In order to verify these findings were performed immunohistochemical investigations on the expression of fibronectin in incised wounds of porcine skin inflicted into various anatomical regions in the early postmortem interval (0-5 min after circulatory arrest). Tissue specimens were collected 12-14 h postmortem and investigated for fibronectin on paraffin sections (alkaline phosphatase and monoclonal anti-alkaline phosphatase procedure). A markedly positive expression of fibronectin (not only next to the wound margin and clearly stronger than in normal undamaged skin) could be demonstrated in eleven out of 36 samples. A moderately positive fibronectin reaction was detectable in seven further specimens. Muscular contraction bands were observed in nine out of 36 specimens. The various reaction patterns of fibronectin cannot be finally explained, but are probably due to a passive transudation of skin tissue by blood components from injured vessels. As a result of these investigations the specificity and validity of fibronectin as a parameter of vitality has to be questioned. Fibronectin immunohistochemistry again reveals that the validity of parameters as vital criteria decreases when their manifestation time is short; postmortem/supravital induction seems to be possible resembling vital reactions in these cases.