Immunohistochemical detection of early myocardial infarction: a systematic review

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.

Morphological and Genetic Aspects for Post-Mortem Diagnosis of Hypertrophic Cardiomyopathy: A Systematic Review

Hypertrophic cardiomyopathy (HCM) is one of the most common genetic cardiovascular diseases, and it shows an autosomal dominant pattern of inheritance. HCM can be clinically silent, and sudden unexpected death due to malignant arrhythmias may be the first manifestation. Thus, the HCM diagnosis could be performed at a clinical and judicial autopsy and offer useful findings on morphological features; moreover, it could integrate the knowledge on the genetic aspect of the disease. This review aims to systematically analyze the literature on the main post-mortem investigations and the related findings of HCM to reach a well-characterized and stringent diagnosis; the review was performed using PubMed and Scopus databases. The articles on the post-mortem evaluation of HCM by gross and microscopic evaluation, imaging, and genetic test were selected; a total of 36 studies were included. HCM was described with a wide range of gross findings, and there were cases without morphological alterations. Myocyte hypertrophy, disarray, fibrosis, and small vessel disease were the main histological findings. The post-mortem genetic tests allowed the diagnosis to be reached in cases without morpho-structural abnormalities; clinical and forensic pathologists have a pivotal role in HCM diagnosis; they contribute to a better definition of the disease and also provide data on the genotype-phenotype correlation, which is useful for clinical research.

An Insight into Kounis Syndrome: Bridging Clinical Knowledge with Forensic Perspectives

Kounis syndrome (KS) is an acute coronary syndrome triggered by allergic or hypersensitivity reactions. Incidence rates vary, with studies reporting 19.4 per 100.000 among all admissions and 3.4% among allergy patients. This review explores the expanding understanding of KS, encompassing various manifestations, and focusing on both clinical data and forensic findings useful in performing a diagnosis. The pathophysiology of this syndrome involves a complex interplay between allergic reactions and the cardiovascular system. Mast cell activation, histamine release, leukotrienes, cytokines, and platelet activation can contribute to coronary events. Three types of classification systems (allergic angina, allergic myocardial infarction, allergic stent thrombosis) aid in categorizing presentations. The diagnosis of KS relies on clinical presentation, laboratory findings, and imaging. Postmortem assessment of KS is based on the integration of circumstantial data, autopsy, and histological findings. Biochemical and immunohistochemical analyses also contribute to postmortem diagnosis. In conclusion, a combined, multidisciplinary approach should be used to ease the diagnostic process, which is crucial for forensic practitioners in confirming KS occurrence.

Postmortem biochemistry in deaths from ischemic heart disease

Ischemic heart disease (IHD) is one of the leading causes of morbidity and sudden cardiac death worldwide and is an important public health problem. The presence of ischemia in clinical applications can be detected by ECG, biochemical markers, and radiological methods. Myocardial infarction is also frequently encountered in forensic autopsies. Postmortem diagnosis is determined as a result of histopathological examinations and additional exclusionary examinations (toxicology, microbiology, etc.). However, routine histopathological examinations are insufficient, especially when death occurs in the early period of ischemia. It creates a problem for forensic pathologists and forensic medicine specialists in such cases of sudden cardiac death. Postmortem biochemistry is one of the important and promising disciplines in which forensic applications work in order to diagnose these cases correctly. The issue of whether biomarkers used in the diagnosis of myocardial infarction in clinical studies can be used reliably in postmortem cases has been discussed by forensic medicine researchers for some time. This manuscript aims to review and summarize biomarkers belonging to various categories that have been studied in IHD-related deaths, in biological fluids taken at autopsy, or in animal experiments. Our study shows that the postmortem use of biochemical markers in the diagnosis of IHD yields promising results. However, it should not be forgotten that postmortem biochemistry is different from clinical applications due to its dynamics and that the body causes unpredictable changes in markers in the postmortem process. Therefore, comprehensive studies are needed to evaluate the postmortem stability of these markers in different biological fluids, their significance among various causes of death, and whether they are affected by any variable (Cardiopulmonary resuscitation, Postmortem interval, medications, etc.) before they are routinely applied. It is suggested by the authors that the cut-off values of biomarkers whose significance has been proven by these studies should be determined and that they should be used in this way in routine applications.

Recent perspectives on the early expression immunohistochemical markers in post-mortem recognition of myocardial infarction

Acute Myocardial Infarction (AMI) refers to the death of heart tissue in the absence ofperfusion. It is one of the top causes of death globally, particularly in middle andhigher-age groups. However, for the pathologist, the post-mortem macroscopic andmicroscopic diagnosis of early AMI remains challenging. In the early acute stage ofAMI, no microscopic visible signs of tissue alterations like necrosis and neutrophilinfiltration can be seen. In such a scenario, immunohistochemistry (IHC) accounts forthe most suitable and safest alternative to study early diagnostic cases by selectivelydetecting changes in the cell population. This systematic review focuses on themultiple causes/changes that lead to the privation of blood flow as well as tissuechanges induced by the absence of perfusion.We performed a systematic review of the last 10-15 years' publications that focused ondetecting immunohistochemical changes that appear in the cell population in case ofacute myocardial infarction. We found around 160 articles on AMI, which we narroweddown to 50 with the use of specific filters such as: "Acute Myocardial Infarction," "Ischemia," "Hypoxia," "Forensic," "Immunohistochemistry, and "Autopsy." The presentreview comprehensively highlights the current knowledge of specific IHC markers usedas gold standards during post-mortem investigation of acute myocardial infarction. Thepresent review comprehensively highlights the current knowledge of specific IHCmarkers used as gold standards during post-mortem investigation of acute myocardialinfarction, and some new potential immunohistochemical markers that can be used inthe early detection of myocardial infarction.

Systematic Review on Post-Mortem Protein Alterations: Analysis of Experimental Models and Evaluation of Potential Biomarkers of Time of Death

Estimating the post-mortem interval (PMI) is a very complex issue due to numerous variables that may affect the calculation. Several authors have investigated the quantitative and qualitative variations of protein expression on post-mortem biological samples in certain time intervals, both in animals and in humans. However, the literature data are very numerous and often inhomogeneous, with different models, tissues and proteins evaluated, such that the practical application of these methods is limited to date. The aim of this paper was to offer an organic view of the state of the art about post-mortem protein alterations for the calculation of PMI through the analysis of the various experimental models proposed. The purpose was to investigate the validity of some proteins as “molecular clocks” candidates, focusing on the evidence obtained in the early, intermediate and late post-mortem interval. This study demonstrates how the study of post-mortem protein alterations may be useful for estimating the PMI, although there are still technical limits, especially in the experimental models performed on humans. We suggest a protocol to homogenize the study of future experimental models, with a view to the next concrete application of these methods also at the crime scene.

Immunohistochemical analysis of vimentin expression in myocardial tissue from autopsy cases of ischemic heart disease

Vimentin is a type III intermediate filament cytoskeletal protein that is expressed mainly in cells of mesenchymal origin and is involved in a plethora of cellular functions. In this study, myocardial tissues from patients with ischemic heart disease and a mouse model of acute myocardial infarction were subjected to immunohistochemistry for vimentin. We first examined 26 neutral formalin-fixed, paraffin-embedded myocardial tissue samples from autopsies of patients that were diagnosed with ischemic heart disease within 48 h postmortem. Myocardial cells were negative for vimentin, whereas non-myocardial cells, including vascular endothelium, vascular smooth muscle, fibroblasts, nerve fibers, adipocytes and mesothelial cells, showed positivity. Elevated vimentin expression was observed around myocardial cells undergoing remodeling, suggesting fibroblastic and endothelial proliferation in these locations. By contrast, myocardial foci that were completely fibrotic did not show upregulated vimentin expression. Inflammatory foci including macrophages and neutrophils were clearly visualized with vimentin immunostaining. The same vimentin expression phenomena as those found in human samples were observed in the mouse model. Our study indicates that immunostaining of vimentin as a marker for myocardial remodeling and the dynamics of all non-myocardial cell types may be useful for supplementing conventional staining techniques currently used in the diagnosis of ischemic heart disease.

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.

Immunohistochemical analysis of von Willebrand factor expression in myocardial tissues from autopsies of patients with ischemic heart disease

von Willebrand factor (VWF) plays a crucial role in hemostasis and thrombosis. VWF is involved in platelet attachment to the subendothelium, serving as a carrier protein for coagulation factor VIII. In this study, myocardial tissues from deceased patients with ischemic heart disease and a mouse model of acute myocardial infarction were subjected to immunohistochemistry to determine VWF expression. We examined 28 neutral formalin-fixed, paraffin-embedded myocardial tissue samples obtained from the autopsies of patients who were diagnosed with ischemic heart disease within 48 h postmortem. Most myocardial cells were negative for VWF, although some cells showed nonspecific positivity. Elevated VWF expression was observed around myocardial cells undergoing remodeling, suggesting that endothelial proliferation occurred at these sites. In contrast, completely fibrotic myocardial foci did not show upregulated VWF expression. Positivity in fibrin deposition and hemorrhagic sites was observed. The same VWF expression characteristics as those observed in the human samples were observed in the mouse model. VWF immunostaining as an endothelial marker may be a useful supplementation to conventional staining techniques that are currently used in the diagnosis of ischemic heart disease in terms of examining the timing of myocardial remodeling in detail and highlighting the remodeling process.

Endoplasmic reticulum stress-related secretory proteins as biomarkers of early myocardial ischemia-induced sudden cardiac deaths

Early myocardial ischemia-induced sudden cardiac deaths (EMI-SCD) remain a great diagnostic challenge for forensic pathologists due to no gross or non-specific histological pathology. The goal of this study was to assess whether three secretory proteins, related with cellular endoplasmic reticulum stress, can be applied in forensic diagnosis of EMI-SCD. These markers included LMAN2, CAPN-1, and VCP and were compared with two clinically used markers (CK-MB and cTnI). A total of 21 EMI-SCD cases with a mean age of 53.0 (± 10.5) years and a mean ischemia interval of < 2.77 (± 2.56) hours were collected. Another 23 cases (mean 44.6 ± 15.0 year old) that died from non-cardiac causes served as control. Enzyme-linked immunosorbent assay (ELISA) was performed to detect target proteins' serum concentrations in the EMI-SCD and control groups. We found that LMAN2, CAPN-1, and VCP were all significantly increased in the EMI-SCD group as compared with control serum, with the fold changes ranging from 1.48 (p = 0.0022, LMAN2), 1.33 (p = 0.041, CAPN-1), to 1.26 (p = 0.021, VCP), respectively. The concentrations of these proteins remained highly stable within 6 h and were not affected by death time, postmortem interval (< 4 h), age, and month at death. Receiver operating characteristic (ROC) curves showed that the areas under the curve (AUC) were 0.8178 (LMAN2), 0.6988 (CAPN-1), and 0.7267 (VCP), all of which were higher than CK-MB (AUC 0.5590) and cTn-I (AUC 0.5911). The diagnostic specificity (all above 60%) was obviously higher than CK-MB (43.48%) and cTnI (34.78%). In conclusion, LMAN-2, CAPN-1, and VCP could be stable serological biomarkers for diagnosis of EMI-SCD cases.

Dystrophin and metalloproteinase 9 in myocardial ischemia: A post-mortem immunohistochemical study

The presented study evaluated the expression of dystrophin and MMP-9 in cases of sudden cardiac death (SCD) due to coronary atherosclerotic disease (CAD) in order to analyze the characteristics and the chronology of their expression, providing evidence on the possible role in post-mortem diagnosis of myocardial ischemia. The expression of these proteins was also compared to C5b-9 complex and fibronectin expression to evaluate any differences. Two groups of CAD-related SCD, respectively group 1 with gross and/or histological evidence and group 2 with no specific histological signs of myocardial ischemia, were used. A third group formed by cases of acute mechanical asphyxiation was used as a control. The immunohistochemical staining by dystrophin, MMP-9, C5b-9, and fibronectin antibodies was performed. The study revealed that dystrophin and MMP-9 showed different expression in group 1 and group 2 as, respectively, different degree of sarcolemmal staining depletion and increasing of interstitial and granulocytes immunopositivity. Moreover, loss of dystrophin staining and C5b-9 immunopositivity were more significant when compared to MMP-9 increasing. Dystrophin and MMP-9 seemed to be useful immunohistochemical markers for the detection of myocardial ischemic damage. However, the comparison of the four markers suggested that loss of dystrophin could be considered as an earlier marker.

Effect of unilateral renal ischemia on the contralateral kidney assessed by Caspase 3 expression

Background

Studies have demonstrated with histological analysis and Doppler flow measurement analysis that unilateral renal ischemia, which is performed in some surgeries, interfered with the contralateral kidney, identifying the phenomenon of kidney-kidney crosstalk.

Objectives

To identify the effects on the ischemic and contralateral kidney of renal ischemia induced by two types of clamping technique by analyzing the volume of kidney cells positive for Caspase 3.

Methods

Sixteen pigs were divided into 2 groups, as follows: A (n = 8) – clamping of left renal artery only and AV (n = 8) – clamping of left renal artery and vein. Immunohistochemical analyses (anti Caspase 3) were conducted with biopsy specimens collected from the ischemic and contralateral kidney at 0, 30, 60, and 90 minutes of ischemia and morphometric analysis was performed, taking the mean to represent the volume of the Caspase 3 positive area (%).

Results

Morphometric analysis of specimens collected at 30, 60, and 90 minutes of ischemia showed that the mean area marked for Caspase 3 was statistically larger in the contralateral kidney than the ischemic kidney in both groups: clamped renal artery (A) and clamped renal artery and vein (AV). Comparing the ischemic and contralateral kidney, there was no statistically significant difference in the area marked for Caspase 3 between the two types of clamping.

Conclusions

In the experimental model of unilateral renal ischemia, the non-ischemic kidney exhibited cell damage, demonstrated by Caspase 3 expression. The type of hilum clamping does not appear to influence the area marked for Caspase 3.

Estimation of postmortem interval in myocardial stab wounds and firearm injuries: An immunohistochemical comparative study using C5b-9 and cardiac Troponin C

BACKGROUND

Estimation of postmortem interval (PMI) is a critical component of forensic death investigations. C5b-9 and cardiac Troponin C (cTnC) have the potential as markers for myocardial damage and can be suitable markers for determination of PMI. The aim of current study was to estimate different postmortem intervals using C5b-9 and cTnC detected by immunohistochemical technique in stab wounds and firearm injuries of the heart.

MATERIALS AND METHODS

Cardiac tissue samples from 70 forensic autopsy cadavers were obtained from XXXXXXX morgue, processed, for histopathological examination as well as immunohistochemical detection of C5b-9 and cTnC expression. The surface area of the positive C5b-9 and troponin C immune reactive cardiac tissue was measured morphometrically then the data were used to construct multiple regression equations for the estimation of PMI.

RESULTS

Histopathological autolytic changes occurred in all groups and increased in intensity with the increase in the PMI in stab wound and firearm injury groups. These findings were supported by immunohistochemical morphometric analysis. Constructed equations to estimate PMI were highly accurate especially those combining both markers.

CONCLUSION

C5b-9 and cTnC can be considered reliable indicators of myocardial damage and can be used either separately or in combination for accurate estimation of PMI.

Investigation of the skin lesions in lightning strike death

Lightning strike-related deaths are unusual, and the victim bodies can present different lesions due to the different injury mechanisms associated with this event. Since the post mortem assessment can be challenging, the evaluation of the characteristics of the skin lesions becomes fundamental to reconstruct the event. Due to the paucity of literature on this topic, the authors report the case of a 59-year-old man found dead near his home after a thunderstorm. Initially considered a murder by gunshot, the autopsy revealed the typical lightning strike lesions, also known as Lichtenberg figures. The adequate interpretation of the autopsy data and the histological evidences allowed to reconstruct the death dynamic and to relate it to a lightning strike. The main lesions due to lightening are here reported and discussed in order to provide a workflow for the identification of lightening as cause of death in unwitnessed cases.

Immunohistochemical analysis of thrombomodulin expression in myocardial tissue from autopsy cases of ischemic heart disease

Thrombomodulin is a transmembrane glycoprotein that is ubiquitously expressed on the surface of vascular endothelial cells. Thrombomodulin exerts its anticoagulant effects by combining with thrombin, activating protein C, and inactivating the coagulation factors FVa and FVIIIa. Clinically, thrombomodulin is also known as a marker of vascular injury because it circulates freely in response to endothelial injury. In this study, myocardial tissue from cases of ischemic heart disease was subjected to immunohistochemistry by thrombomodulin. We examined 40 neutral-formalin-fixed, paraffin-embedded myocardial tissue samples from autopsy cases that were diagnosed with ischemic heart disease (within 48 h postmortem). Thrombomodulin expression was observed in vascular endothelial cells between myocardial cells and in mesothelial cells of the epicardium. In necrotic myocardium, diffusion of thrombomodulin, which reflected endothelial injury, was observed. Upregulated thrombomodulin expression was observed around myocardial cells under ongoing remodeling, which suggested endothelial proliferation in these locations. Completed fibrotic foci of the myocardium did not show upregulated thrombomodulin expression. In a mouse model of acute myocardial infarction, the same phenomena as that found in human samples were observed by immunohistochemistry of thrombomodulin. Immunostaining of thrombomodulin, as a marker for endothelial injury or myocardial remodeling, may be useful for supplementing conventional staining techniques in the diagnosis of ischemic heart disease in forensic pathology.

Pathological Findings in COVID-19 as a Tool to Define SARS-CoV-2 Pathogenesis. A Systematic Review

Introduction: The World Health Organization declared the COVID-19 pandemic in March 2020. COVID-19 still represents a worldwide health emergency, which causesa severe disease that has led to the death of many patients. The pathophysiological mechanism of SARS-CoV-2 determining the tissue damage is not clear and autopsycan be auseful tool to improve the knowledge of this infection and, thus, it can help achieve a timely diagnosis and develop an appropriate therapy. This is an overview of the main post-mortem findings reporting data on the infection effects on several organs. Methods: A systematic literature search was conducted in the PubMed database searching for articles from 1 January to August 31, 2020. Thearticles were selected identifying words/concepts in the titles and/or abstracts that indicated the analysis of the morphological/pathological tissue injuries related to SARS-CoV-2 disease by several investigations. Results: A total of 63 articles were selected. The main investigated tissue was the lung showing a diffuse alveolar damage (DAD) frequently associated with pulmonary thrombotic microangiopathy. Inflammatory findings and vascular damage were observed in other organs such as heart, liver, kidney, brain, spleen, skin and adrenal gland. The immunohistochemical analysis showed tissue inflammatory cells infiltrates. The virus presence was detected by several investigations such as RT-PCR, immunohistochemistry and electron microscope, showing the effect ofSARS-CoV-2not exclusively in the lung. Discussion: The evidence emerging from this review highlighted the importance of autopsy to provide a fundamental base in the process of understanding the consequences ofSARS-CoV-2 infection. COVID-19 is strictly related to a hyper inflammatory state that seems to start with DAD and immuno-thrombotic microangiopathy. Massive activation of the immune system and microvascular damage might also be responsible for indirect damage to other organs, even if the direct effect of the virus on these tissues cannot be excluded.

Immunohistochemistry in the Detection of Early Myocardial Infarction: Systematic Review and Analysis of Limitations Because of Autolysis and Putrefaction

The postmortem diagnosis of acute myocardial infarction is one of the main problems in forensic practice, especially in cases in which death occurs soon after (from minutes to a few hours) the onset of the ischemic damage. Several authors have highlighted the possibility to overcome the limits of conventional histology in this diagnosis by utilizing immunohistochemistry. In the present research, we examined over 30 scientific studies and picked out over 20 main immunohistochemical antigens analyzed with a view to enabling the rapid diagnosis of early myocardial infarction. The aim of our review was to examine and summarize all the principal markers studied to date and also to consider their limitations, including protein alteration because of cadaveric autolysis and putrefaction.

Membrane Attack Complex in Myocardial Ischemia/Reperfusion Injury: A Systematic Review for Post Mortem Applications

The complement system has a significant role in myocardial ischemia/reperfusion injury, being responsible for cell lysis and amplification of inflammatory response. In this context, several studies highlight that terminal complement complex C5b-9, also known as the membrane attack complex (MAC), is a significant contributor. The MAC functions were studied by many researchers analyzing the characteristics of its activation in myocardial infarction. Here, a systematic literature review was reported to evaluate the principal features, advantages, and limits (regarding the application) of complement components and MAC in post mortem settings to perform the diagnosis of myocardial ischemia/infarction. The review was performed according to specific inclusion and exclusion criteria, and a total of 26 studies were identified. Several methods studied MAC, and each study contributes to defining better how and when it affects the myocardial damage in ischemic/reperfusion injury. The articles were discussed, focusing on the specificity, sensibility, and post mortem stability of MAC as a marker of myocardial ischemia/infarction, supporting the usefulness in routine post mortem investigations.

Post-Mortem Investigations for the Diagnosis of Sepsis: A Review of Literature

To date, sepsis is still one of the most important causes of death due to the difficulties concerning the achievement of a correct diagnosis. As well as in a clinical context, also in a medico-legal setting the diagnosis of sepsis can reveal challenging due to the unspecificity of the signs detected during autopsies, especially when no ante-mortem clinical data, laboratory, and cultural results are available. Thus, a systematic review of literature was performed to provide an overview of the main available and updated forensic tools for the post-mortem diagnosis of sepsis. Moreover, the aim of this review was to evaluate whether a marker or a combination of markers exist, specific enough to allow a correct and definite post-mortem diagnosis. The review was conducted searching in PubMed and Scopus databases, and using variable combinations of the keywords "post mortem sepsis diagnosis", "macroscopic signs", "morphology", "histology", "immunohistochemical markers", "biochemical markers", and "forensic microbiology". The article selection was carried out following specific inclusion and exclusion criteria. A total of 44 works was identified, providing data on morphological aspects of the organs examined, histological findings, immunohistochemical and biochemical markers, and cultural assays. The review findings suggested that the post-mortem diagnosis of sepsis can be achieved by a combination of data obtained from macroscopic and microscopic analysis and microbial investigations, associated with the increased levels of at least two of three biochemical and/or immunohistochemical markers evaluated simultaneously on blood samples.

T2 and T2∗ mapping in ex situ porcine myocardium: myocardial intravariability, temporal stability and the effects of complete coronary occlusion

Diagnosis of ischaemia-related sudden cardiac death in the absence of microscopic and macroscopic ischaemic lesions remains a challenge for medical examiners. Medical imaging techniques increasingly provide support in post-mortem examinations by detecting and documenting internal findings prior to autopsy. Previous studies have characterised MR relaxation times to investigate post-mortem signs of myocardial infarction in forensic cohorts. In this prospective study based on an ex situ porcine heart model, we report fundamental findings related to intramyocardial variability and temporal stability of T₂ as well as the effects of permanent coronary occlusion on T₂ and T₂^∗ relaxation in post-mortem myocardium. The ex situ porcine hearts included in this study (n= 19) were examined in two groups (S_s, n= 11 and S_i, n= 8). All magnetic resonance imaging (MRI) examinations were performed ex situ, at room temperature and at 3 T. In the S_s group, T₂ mapping was performed on slaughterhouse porcine hearts at different post-mortem intervals (PMI) between 7 and 26 h. Regarding the intramyocardial variability, no statistically significant differences in T₂ were observed between myocardial segments (p= 0.167). Assessment of temporal stability indicated a weak negative correlation (r=- 0.21) between myocardial T₂ and PMI. In the S_i group, animals underwent ethanol-induced complete occlusion of the left anterior descending artery. T₂ and T₂^∗ mapping were performed within 3 h of death. Differences between the expected ischaemic and remote regions were statistically significant for T₂ (p= 0.007), however not for T₂^∗ (p= 0.062). Our results provide important information for future assessment of the diagnostic potential of quantitative MRI in the post-mortem detection of early acute myocardial infarction.

Post-Mortem Immunohistochemical Evidence of β2-Adrenergic Receptor Expression in the Adrenal Gland

The evidence from post-mortem biochemical studies conducted on cortisol and catecholamines suggest that analysis of the adrenal gland could provide useful information about its role in human pathophysiology and the stress response. Authors designed an immunohistochemical study on the expression of the adrenal β2-adrenergic receptor (β2-AR), a receptor with high-affinity for catecholamines, with the aim to show which zones it is expressed in and how its expression differs in relation to the cause of death. The immunohistochemical study was performed on adrenal glands obtained from 48 forensic autopsies of subjects that died as a result of different pathogenic mechanisms using a mouse monoclonal β2-AR antibody. The results show that immunoreactivity for β2-AR was observed in all adrenal zones. Furthermore, immunoreactivity for β2-AR has shown variation in the localization and intensity of different patterns in relation to the original cause of death. To the best of our knowledge, this is the first study that demonstrates β2-AR expression in the human cortex and provides suggestions on the possible involvement of β2-AR in human cortex hormonal stimulation. In conclusion, the authors provide a possible explanation for the observed differences in expression in relation to 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.

Biomarkers in acute myocardial infarction: current perspectives

PURPOSE

Acute myocardial infarction (AMI) is the most common cause of death in the world. Comprehensive risk assessment of patients presenting with chest pain and eliminating undesirable results should decrease morbidity and mortality rates, increase the quality of life of patients, and decrease health expenditure in many countries. In this study, the advantages and disadvantages of the enzymatic and nonenzymatic biomarkers used in the diagnosis of patients with AMI are given in historical sequence, and some candidate biomarkers - hFABP, GPBB, S100, PAPP-A, RP, TNF, IL6, IL18, CD40 ligand, MPO, MMP9, cell-adhesion molecules, oxidized LDL, glutathione, homocysteine, fibrinogen, and D-dimer procalcitonin - with a possible role in the diagnosis of AMI are discussed.

METHODS

The present study was carried out using meta-analyses, reviews of clinical trials, evidence-based medicine, and guidelines indexed in PubMed and Web of Science.

RESULTS

These numerous AMI biomarkers guide clinical applications (diagnostic methods, risk stratification, and treatment). Today, however, TnI remains the gold standard for the diagnosis of AMI. Details in the text will be given of many biomarkers for the diagnosis of AMI.

CONCLUSION

We evaluated the advantages and disadvantages of routine enzymatic and nonenzymatic biomarkers and the literature evidence of other candidate biomarkers in the diagnosis of AMI, and discuss challenges and constraints that limit translational use from bench to bedside.

Postmortem Diagnosis of Myocardial Infarction Due to Butane Gas Intoxication in a Child: A Case Report

Volatile substance addiction and toxic gas inhalation are now an important health problem. The pleasure-based inhalation of butane gas, also known as lighter refill gas, is especially prevalent among children and young people. The most important reasons for this situation are that they are cheap and easy to obtain and lack of legal supervision. The exhaled gas is absorbed through the alveolar surface and rapidly enters the bloodstream and leads to clinical signs. It can cause dizziness, nausea, vomiting, confusion, hallucinations, and euphoria in the acute phase. In severe cases, bronchospasm, hypoxia, ventricular arrhythmia, cardiopulmonary arrest, and death can occur. Our case is one of the rare cases in the literature that was diagnosed by postmortem histopathological examination. Our case is a 15-year-old girl who was found in front of a tobacco product store. On gross examination, there was a hemorrhagic area under the aortic valve that continued to interventricular septum. There was no coronary artery lesion. Histopathological examination revealed hypereosinophilia and contraction band necrosis in myocardial fibers, which was more intense in papillary muscle. Immunohistochemical studies also supported early myocardial ischemic changes. Upon toxicological examination, butane gas was detected in lung and blood samples.

An Aptamer-based Biosensor for Troponin I Detection in Diagnosis of Myocardial Infarction

BACKGROUND

Acute myocardial infarction (MI) accounts for one third of deaths. Cardiac troponin I (TnI) is a reliable biomarker of cardiac muscle tissue injury and is employed in the early diagnosis of MI.

OBJECTIVE

In this study, a molecular method is introduced to early diagnosis of MI by rapid detection of TnI.

MATERIALS AND METHODS

The detection method was based on electrochemical aptasensing, being developed using different methods and evaluation steps. A gold electrode was used as a transducer to successful immobilize 76base aptamer to fabricate a TnI biosensor.

RESULTS

The designed aptasensor could detect TnI in a range of 0.03 to 2.0 ng mL-1 without using any label, pre-concentration or amplification steps. The limit of detection was attained as 10 pg mL-1 without significant trouble of interfering species. The TnI biosensor demonestrated a stable, regenerative and reproducible function. 89 human samples were used to evaluate the performance of the TnI biosensor, and it represented 100% and 81%, diagnostic sensitivity and specificity, respectively.

CONCLUSION

This aptasensor may be used as an applicable tool in the future of early medical diagnosis of MI.

Immunohistochemical study on dystrophin expression in CAD-related sudden cardiac death: a marker of early myocardial ischaemia

The aims of this study were to assess if dystrophin can be a tool for the forensic evaluation of sudden cardiac death due to coronary atherosclerotic disease (CAD) and particularly if it can be a marker of early myocardial ischaemia. Then in this investigation, the dystrophin was compared to C5b-9 and fibronectin to analyze if there are some differences in the expression of these proteins. Two groups of CAD-related sudden cardiac death, respectively the group 1 with gross and/or histological evidence and the group 2 with no specific histological signs of myocardial ischaemia were used. A third group formed by cases of acute mechanical asphyxiation was used as a control. The immunohistochemical staining by dystrophin, C5b-9 and fibronectin antibodies was performed. Loss of sarcolemmal dystrophin was observed in different degrees according to more or less significant histological evidence of myocardial ischaemia. Moreover, the comparison between loss of dystrophin expression and fibronectin positivity showed significant differences in group 2. The results suggested that dystrophin can be used in forensic diagnosis of CAD-related sudden cardiac death and as marker of early myocardial ischaemia.

Analysis on sarcoglycans expression as markers of septic cardiomyopathy in sepsis-related death

The post-mortem assessment of sepsis-related death can be carry out by many methods recently suggested as microbiological and biochemical investigations. In these cases, the cause of death is a multiple organ dysfunction due to a dysregulated inflammatory response occurring after the failure of infection control process. It was highlighted also that the heart can be a target organ in sepsis which determines the so-called septic cardiomyopathy characterized by myocardial depression. Several mechanisms to explain the pathophysiology of septic cardiomyopathy were suggested, but very few studies about the structural alterations of cardiac cells responsible for myocardial depression were carried out. The aim of this study was to evaluate whether sarcoglycans (SG) were involved in septic cardiac damage analyzing their expression in sepsis-related deaths and, particularly, if these proteins can be used as markers of septic myocardial dysfunction. Cases of septic-related death confirmed by clinical and autopsy records were investigated and compared to a control group of traumatic deaths. Indirect immunofluorescence analysis was performed to analyze α-SG, β-SG, δ-SG, ζ-SG, ε-SG, and γ-SG. Decrease of fluorescence staining pattern for all tested sarcoglycans was observed in the septic-related deaths compared to normal fluorescence staining pattern of control group. These results provide new findings about the myocytes structural alterations due to sepsis and suggest that these proteins could be used in forensic assessment of septic cardiomyopathy.