Detection of cardiomyocyte apoptosis in forensic autopsy cases

Lighting up forensic science by aggregation-induced emission: A review

Forensic science requires a fast, sensitive, and anti-interfering imaging tool for on-site investigation and bio-analysis. The aggregation-induced emission (AIE) phenomenon exhibits remarkable luminescence properties (large Stokes shift, diverse molecular structures, and high photo-stability), which can provide a viable solution for on-site analysis, while at the same time overcoming the problem of aggregation-caused quenching (ACQ). Based on the outstanding performance in chemical analysis and bio-sensing, AIE materials have great prospects in the field of forensic science. Therefore, the application of AIE in forensic science has been summarized for the first time in this article. After a brief introduction to the concept and development of AIE, its applications in the determination of toxic or hazardous substances, based on data on poisoning deaths, has been summarized. Subsequently, besides the bio-imaging function, other applications of AIE in analyzing markers related to forensic genetics, forensic pathology, (focusing on the corpse) and clinical forensics (focusing on the living) have been discussed. In addition, applications of AIE molecules in criminal investigations, including recognition of fingerprints and blood stains, detection of explosives and chemical warfare agents, and anti-counterfeiting have also been presented. It is hoped that this review will light up the future of forensic science by stimulating more research work on the suitability of AIE materials in advancing forensic science.

When is myocarditis indeed the cause of death?

Attribution of death to myocarditis continues to be a controversial issue in forensic pathology, despite the existence of established histopathological criteria as well as complementary investigations. The aim of the study was two-fold: (a) to retrospectively analyse the data obtained from a series of clinical and forensic autopsies in order to assess the number of cases with death attributed to myocarditis, and (b) to reevaluate these cases in order to assess how properly the histopathological diagnosis of myocarditis conformed to established criteria and therefore how accurately these were used on the basis of all postmortem investigation findings to conclude the cause of death. 2474 clinical and forensic autopsies were taken into consideration. Myocarditis was recorded as the official, underlying cause of death in 48 cases. Of those, 8 cases were considered to accurately conform to the histopathological Dallas criteria for the presence of myocarditis and could therefore be classified as cases of fatal myocarditis. In 19 out of 48 cases, description of focal myocarditis was considered to accurately fulfill the histopathological Dallas criteria for the presence of myocarditis. However, data provided by histological analysis and virology testing result reevaluation allowed alternative causes of death to be speculated. In another 21 out of 48 cases, description of focal myocardial inflammation was considered to inaccurately meet the histopathological Dallas criteria for the presence of myocarditis. The findings of our own study appear to be in agreement with previous observations in similar study groups and highlight that since myocarditis may occur in association with many diseases, a great deal of evidence is required before settling on categorical conclusions.

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.

The effectiveness and limitations of triphenyltetrazolium chloride to detect acute myocardial infarction at forensic autopsy

Triphenyltetrazolium chloride (TTC) is one of the most conventional stains to detect infarcted area of the heart in animal experiments. However, its availability and limitations have not been thoroughly discussed in the forensic field. Here, authors stained human hearts with TTC soon after the harvest. Photographs of the samples were analyzed using image analysis software, which evaluated the occupying ratio of the stained area on the surface of each slice. The results showed that the stainability of TTC declines with the length of the postmortem interval (PMI). Specimens reacted well to TTC within 1.5 days after death and then decreased the stainability logarithmically with PMI (y = - 0.294 In (x) + 1.0441; x = PMI, y = TTC-stained area / total myocardial area, R = 0.5673). Samples with old myocardial infarction produced clear TTC contrast; normal tissue is vivid red, and fibrotic myocardium is white discoloration. In acute myocardial infarction cases where death occurred within 9 hours after the attack, however, the detection of infarcted area was very difficult even when PMI was less than 1.5 days. In summary, the TTC method may be useful within 1.5 days after death, but short suffering period before death disturbs its staining efficiency.

Caspases in myocardial infarction

The discovery of apoptosis sheds a new light on the role of cell death in myocardial infarction and other cardiovascular diseases. There is mounting evidence that apoptosis plays an important role at multiple points in the evolution of myocardial infarction, and comprises not only cardiomyocytes but also inflammatory cells, as well as cells of granulation tissue and fibrous tissue. It appears that apoptosis contributes to cardiomyocyte loss in the border zone and in remote myocardium in the early phase, as well as months after myocardial infarction, thus playing a role in remodeling and development of heart failure after myocardial infarction. Apoptosis, being a highly regulated process, is a potential target for therapeutic intervention. Caspases are the key effector molecules in apoptosis, and are therefore a particularly attractive target for pharmacological modulation of apoptosis. Although several potential therapeutic agents have been tested in animal models of ischemia/reperfusion heart injury with some success, nearly none of the specific antiapoptotic agents have reached the stage of clinical research.

Electrocardiographic abnormalities in methamphetamine abusers

AIMS

Although many adverse cardiovascular outcomes are mentioned in conjunction with methamphetamine use, a causal relationship between methamphetamine use and arrhythmia or cardiomyopathy has not been demonstrated in man. Clinical experience with methamphetamine users suggested a higher incidence of electrocardiographic abnormalities. This study seeks to quantify that incidence, among subjects enrolled in a study of adults with methamphetamine dependence.

METHODS

Electrocardiograms obtained during screening in a previous clinical trial were examined. The study population (n = 158) of adults with methamphetamine dependence [Diagnostic and Statistical Manual version IV (DSM IV-TR)] was drawn from five sites across the United States, recruited in the interval 2002-03.

RESULTS

A significant variance from the normal population was noted in the electrocardiograms of the study cohort. Among the abnormalities was a prolongation of the QTc beyond 440 ms in 27.2% of the group. QTc prolongation to this extent poses a particular risk for ventricular arrhythmias, most notably torsades de pointes.

CONCLUSIONS

We believe that this is the first demonstration of clinically significant QTc prolongation in a methamphetamine-using population, and that this has implications for the types of arrhythmias for which this population is at risk. It may further provide a marker for risk of cardiomyopathy. The fact of electrocardiographic changes with potential cardiac risks may be useful in a motivational interviewing approach, in challenging the methamphetamine user's basis for continuing use.

Apoptotic cardiomyocyte death in fatal myocarditis

Acute myocarditis is often a self-limited process with a good outcome. Experimental animal studies have found that cardiomyocyte apoptosis occurs in severe forms of myocarditis. We studied whether cardiomyocyte apoptosis plays a role in the development of fatal acute human myocarditis. Myocardial autopsy samples from subjects who died of acute myocarditis in Finland between 1970 and 1998 were studied. Thirty-three of these cases(16 men and 17 women; 45 +/- 6 years old) were randomly selected for this study. All cases fulfilled the histopathologic Dallas criteria for myocarditis. Eight subjects who had died accidentally served as controls. Apoptotic DNA fragmentation (terminal transferase-mediated DNA nick end labeling) and activation of caspase-3 (immunohistochemistry) were detected. The mode of death was determined retrospectively from all available clinical data. In fatal myocarditis, large amounts of cardiomyocytes showed apoptotic DNA fragmentation or contained active caspase-3 (2.0 +/- 0.3% and 2.8 +/- 0.4%, respectively). In the controls, few apoptotic cardiomyocytes were found (0.008 +/- 0.003% by terminal transferase-mediated DNA nick end labeling and 0.009 +/- 0.003% by detection of active caspase-3, p <0.001 vs myocarditis). The amount of apoptosis did not correlate with the age or gender of the cases, recognized viral etiology, histologic features, or duration of disease. However, more apoptotic cardiomyocytes were detected in the subjects who had myocarditis and had died of heart failure (n = 18) than in those who had myocarditis and died suddenly of cardiac arrest (n = 15; 2.6 +/- 0.4% vs 1.1 +/- 0.2%, p <0.001). In conclusion, cardiomyocyte apoptosis is a common mechanism of myocardial damage in severe acute human myocarditis. Moreover, higher rates of cardiomyocyte apoptosis are associated with the development of fatal heart failure in acute myocarditis.

Pathological changes of the heart in sudden infant death

There are more than 120 different theories on the possible causes of sudden infant death (SID). In particular, dysfunctions of the central nervous system, cardiorespiratory insufficiency due to infections including atypical immune reactions, and cardiac dysregulation have been discussed during the previous decade. Reports on disturbances of the cardiac rhythmogenic function due to LQTS were among the most speculative. Based on gross histological, immunohistochemical and molecular genetic investigations of SID cases, the most important and most frequent findings of the heart are shown. The significance of different types of myocarditis, hypoxia-related changes, disturbances of the rhythmogenic function, cardiomyopathy, and other changes is discussed with regard to the cause of death. In conclusion, most of the changes reported in the literature are not sufficient to explain the cause of death. Problems in the diagnosis are shown which influence the classification of these disturbances as well as the classification of SID.