Cardiac troponin T in forensic autopsy cases

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.

Significance of postmortem biomarkers and multimarker strategy in sudden cardiac death

The most common cause in the etiology of sudden cardiac death (SCD) is ischemic heart disease due to atherosclerosis. Postmortem diagnosis can be made by histopathological examinations, but routine histopathological examinations are limited, especially in the early period of postmortem ischemia. For this reason, many methods are being investigated for the postmortem diagnosis of ischemia, and postmortem biochemical studies are promising. In our study, we evaluated the biochemical markers; hs-cTnT, NT-proBNP, H-FABP, pentraxin-3, copeptin, ischemic modified albumin (IMA), and PAPP-A in postmortem serums. In forensic pathology practice, it was investigated whether it would be useful to go to the diagnosis by measuring more than one marker in a single biological fluid in SCD cases. The study included 35 sudden cardiac death cases and 24 control cases and as a result of our study, hs-cTnT, NT-proBNP, and H-FABP values were found to be significantly higher in the SCD group than in the control group. Within the scope of the multi-marker strategy, models were tried to be developed in which the markers were used together, and it was concluded that the model consisting of the myocardial ischemia marker hs-cTnT, the myocardial stress marker NT-proBNP, and the inflammation marker pentraxin 3 was the most accurate combination by correctly classifying the cases at a rate of 94.9%. As a result, it was thought that it would be appropriate to use the multi-marker strategy which is widely used in clinical applications, also in forensic medicine applications.

Diagnostic value of cardiac miR-126-5p, miR-134-5p, and miR-499a-5p in coronary artery disease-induced sudden cardiac death

Background

The identification of coronary artery disease-induced sudden cardiac death (CAD-SCD) has always been a medical challenge. MicroRNAs (miRNAs) played vital roles in pathogenesis processes and served as potential biomarkers for cardiovascular and many other diseases. The aim of this study was to investigate the diagnostic value of the specific miRNAs for CAD-SCD.

Methods

A total of 30 autopsy-verified CAD-SCD victims were selected, including 18 individuals who experienced more than once asymptomatic myocardial ischemia (CAD-activated SCD) and 12 victims without prominent pathological features of insufficient blood supply (CAD-silent SCD). Meanwhile, 30 traumatic victims were enrolled as controls. Systematic postmortem examinations were performed in all study population. The expressions of cardiac miR-126-5p, miR-134-5p, and miR-499a-5p were analyzed by real-time quantitative polymerase chain reaction (RT-qPCR).

Results

RT-qPCR showed significant downregulations of miR-126-5p and miR-499a-5p in CAD-SCD victims, with no obvious difference in miR-134-5p. Receiver-operating characteristic analysis revealed the diagnostic performance of miR-126-5p (areas under the curve [AUC] = 0.76) and validated miR-499a-5p (AUC = 0.82) as a sensitive marker. Additionally, the decreased expression of the two specific cardio-miRNAs was detected for discriminating CAD-silent SCD and CAD-activated SCD. Compared with the limited diagnostic value of single miR-126-5p and miR-499a-5p, their combination could achieve better discriminative capacity (AUC = 0.82, sensitivity = 91.7%, specificity = 77.8%).

Conclusion

Cardiac miR-126-5p and miR-499a-5p presented good diagnostic abilities for CAD-SCD, and their combination could help evaluate CAD condition. These targeted miRNAs as novel biomarkers are expected to be useful to discriminate the detailed causes in real SCD cases.

Diagnostic value of high-sensitivity troponin T in postmortem diagnosis of sudden cardiac death

INTRODUCTION

Ischemic heart disease is the most common cause of sudden cardiac death. By autopsy, there may be no histologic evidence of acute myocardial damage few hours after death. The use of cardiac troponins in the postmortem diagnosis of sudden cardiac death is well known in the forensic setting. However, high-sensitivity cardiac troponin T (Hs-TnT) assay in cadaver fluids was tested in few studies. The aim of this study is to assess the diagnostic value of postmortem dosage of Hs-TnT in the diagnosis of sudden cardiac death.

MATERIAL AND METHODS

Our study is prospective, dealing with cadavers autopsied at the Department of Forensic Medicine of the University Hospital Habib Bourguiba of Sfax-Tunisia from December 2016 to April 2018. Were excluded from the study resuscitated cases, severely traumatized victims and cadavers that were examined more than 36 h after death. Levels of Hs-TnT were measured in pericardial fluid, cardiac blood and peripheral blood.

RESULTS

A total of 80 cases were identified with an average age of 44.5 ± 19 years. Hs-TnT levels in pericardial fluid and heart blood were correlated significantly between cardiac and non-cardiac groups with a p-value respectively at 0.14 and 0.04. Receiver-operator characteristic curves analysis showed that the pericardial fluid had the best sensibility (75%) and specificity (64%) with a cut-off level at 17.72 ng/ml and an area under the curve at 0.747. We found also a significant correlation between postmortem interval and Hs-TnT levels in pericardial fluid, cardiac and peripheral blood.

CONCLUSION

Our data indicate that determination of cardiac troponin T by a highly sensitive assay in pericardial fluid may be a powerful aid in the postmortem diagnosis of sudden cardiac death.

Biomarkers of myocardial injury in rats after cantharidin poisoning: Application for postmortem diagnosis and estimation of postmortem interval

Postmortem diagnosis of cantharidin-induced myocardial injury and postmortem interval estimation (PMI) are the challenges in forensic science. Cardiac biomarkers play an important role in the prediction and diagnosis of myocardial injury and can be used to determine the PMI. Based on the evidence, we aimed to explore the biomarkers which may be used for the postmortem diagnosis of cantharidin-induced myocardial injury and PMI estimation using the study of the proteins expression of TN-T, VEGF and HIF-1α by ELISA. Results of this study suggested that postmortem pathological changes were difficult to identify due to the autolysis of myocardium 72 h after death in cantharidin poisoning group. The plasma levels of TN-T and HIF-1α/TN-T are cardiac biomarkers with higher diagnostic accuracy for postmortem diagnosis of cantharidin-induced myocardial injury, VEGF/HIF-1α promises to be a biomarker for PMI estimation. Further studies are needed to verify these biomarkers, based on population, for being a useful tool in postmortem diagnosis of cantharidin-induced myocardial injury and PMI estimation.

Diagnostic Roles of Postmortem cTn I and cTn T in Cardiac Death with Special Regard to Myocardial Infarction: A Systematic Literature Review and Meta-Analysis

Background: Cardiac troponin I (cTn I) and cardiac troponin T (cTn T) are currently widely used as diagnostic biomarkers for myocardial injury caused by ischemic heart diseases in clinical and forensic medicine. However, no previous meta-analysis has summarized the diagnostic roles of postmortem cTn I and cTn T. The aim of the present study was to meta-analyze the diagnostic roles of postmortem cTn I and cTn T for cardiac death in forensic medicine, present a systematic review of the previous literature, and determine the postmortem cut-off values of cTn I and cTn T. Methods: We searched multiple databases for the related literature, performed a meta-analysis to investigate the diagnostic roles of postmortem cardiac troponins, and analyzed the receiver operating characteristic (ROC) curve to determine their postmortem cut-off values. Results and Conclusions: The present meta-analysis demonstrated that postmortem cTn I and cTn T levels were increased in pericardial fluid and serum in cardiac death, especially in patients with acute myocardial infarction (AMI). We determined the postmortem cut-off value of cTn I in the pericardial fluid at 86.2 ng/mL, cTn I in serum at 9.5 ng/mL, and cTn T in serum at 8.025 ng/mL.

The use of cardiac troponin T (cTnT) in the postmortem diagnosis of acute myocardial infarction and sudden cardiac death: A systematic review

Being sudden cardiac death (SCD) and acute myocardial infarction (AMI) frequent occurrences in forensic medicine, extensive research has been published about the use of cardiac troponin T (cTnT) as a potential specific postmortem biochemical marker. However, cTnT has produced uncertain results, leading to the lack of a standardized application in routine postmortem examinations. The present systematic review focuses on the determination of whether cTnT may be considered as a suitable marker for the postmortem diagnosis of AMI and SCD, analysing the literature according to the following criteria: only human experiments, published from 1st January 2001 to 12th April 2018, available in English, on the following databases: (1). Medline/PubMed/MeSH search words: (("heart"[MeSH Terms] OR "cardiac"[All Fields]) AND ("troponin"[MeSH Terms] OR "troponins"[All Fields]) AND forensic[All Fields] AND "postmortem"[All Fields]); (2). Embase, Lilacs and Cochrane Library. 16 full-text articles were included. cTnT has been demonstrated to be elevated in a variety of pathological conditions, not strictly related to cardiac causes, but rather to the severity and extent of myocardial damage from various causes. cTnT levels have been consistently found higher in pericardial fluid than in the peripheral blood. Reviewed studies showed that the most suitable biological sample for cTnT evaluation seems to be pericardial fluid, since it may be less affected by haemolysis of blood. cTnT seems to be quite stable up to a PMI (postmortem interval) smaller than 48h; after this time, a mild time-dependent increase has been demonstrated. CPR seems to have no influence on cTnT values. The postmortem cut-offs differ from clinical ones, and at present no consensus has been reached concerning the postmortem ranges. Further research needs to be carried out in order to establish a common accepted cut-off value for forensic use.

Intra-individual alterations of serum markers routinely used in forensic pathology depending on increasing post-mortem interval

Post-mortem biochemistry of serum markers has been the subject of numerous studies, but in-situ marker stability after death has not been sufficiently evaluated yet. Such laboratory analyses are especially necessary in the cases of functional deaths without morphological evidence of the death causes and also in cardiac death cases with only very short survival times. The aim of the study was to determine the post-mortem stability of commonly-used serum markers at predefined time points. In 20 cases, peripheral venous samples were taken starting immediately after circulatory arrest and ending 48 hours after death. Serum creatinine, urea, 3-β-hydroxybutyrate, tryptase, myoglobin, troponin T, creatin kinase and creatin kinase-MB have been included. For all markers, we observed increasing marker levels for longer post-mortem intervals. Significant marker level changes began two hours after death. Excessive increases were observed for cardiac and muscle markers. Marker levels showed high intra-assay precision. Furthermore, the markers were robust enough to withstand freeze-thaw cycles. Potential contamination of arteriovenous blood did not influence the post-mortem marker levels. Post-mortem blood should be sampled as soon as possible, as increased post-mortem intervals may heavily change marker levels in-situ in individual cases, whereas the markers are mostly unaffected by laboratory conditions.

High-sensitive cardiac troponin hs-TnT levels in sudden deaths related to atherosclerotic coronary artery disease

INTRODUCTION

Ischemic heart disease (IHD) related to atherosclerotic coronary artery disease (CAD) is one of the most prevalent causes of death in Europe. Postmortem evaluation of IHD remains a challenge because of possible non-specific autopsy finding in some autopsy cases, especially in early myocardial ischemia. High-sensitive cardiac troponin T (hs-TnT) is used today in clinical practice as the "gold standard" to diagnose the myocardial ischemia, and might also be applied as an ancillary tool for post-mortem evaluation.

PURPOSE

The goal of this study is to evaluate the diagnostic value of post-mortem serum hs-TnT assay in cases of sudden death related to IHD. We will also investigate the influence of cardiopulmonary resuscitation (CPR) attempts on post-mortem hs-TnT levels.

METHODS

The hs-TnT values in serum were retrospectively analysed in 85 autopsy data. 52 cases with clinical history and morphological results suggesting cardiac ischemia were included in the study group (mean age 53.5; age range 34-75) and 33 cases in the control group (mean age 40.4; age range 15-69). The group's statistical comparison was performed using logistic regression model.

RESULTS

Our study showed a significant non-linear association between hs-TnT serum values and post-mortem diagnosis of sudden deaths related to IHD (p-value 0.005). The shape of the relationship is showing that the probability of death due to IHD increases quickly with a light level of hs-TnT (maximum around 90ng/L) then decreases slightly while remaining at high in values. No significant difference in the hs-TnT serum values was found between the CPR and the non-CPR cases (p-value 0.304).

CONCLUSION

The measurement of hs-TnT serum values might be considered as an ancillary tool for the evaluation of death related to IHD, while taking necessary precautions in the interpretation of the results.

Application of Fourier transform infrared spectroscopy with chemometrics on postmortem interval estimation based on pericardial fluids

Postmortem interval (PMI) evaluation remains a challenge in the forensic community due to the lack of efficient methods. Studies have focused on chemical analysis of biofluids for PMI estimation; however, no reports using spectroscopic methods in pericardial fluid (PF) are available. In this study, Fourier transform infrared (FTIR) spectroscopy with attenuated total reflectance (ATR) accessory was applied to collect comprehensive biochemical information from rabbit PF at different PMIs. The PMI-dependent spectral signature was determined by two-dimensional (2D) correlation analysis. The partial least square (PLS) and nu-support vector machine (nu-SVM) models were then established based on the acquired spectral dataset. Spectral variables associated with amide I, amide II, COO-, C-H bending, and C-O or C-OH vibrations arising from proteins, polypeptides, amino acids and carbohydrates, respectively, were susceptible to PMI in 2D correlation analysis. Moreover, the nu-SVM model appeared to achieve a more satisfactory prediction than the PLS model in calibration; the reliability of both models was determined in an external validation set. The study shows the possibility of application of ATR-FTIR methods in postmortem interval estimation using PF samples.

Cardiac troponins and NT-proBNP in the forensic setting: Overview of sampling site, postmortem interval, cardiopulmonary resuscitation, and review of the literature

The possible use of biochemical markers in the postmortem diagnosis of myocardial ischemia is well known in the forensic setting, though several issues have limited its widespread adoption. The study presented herein focuses of N-terminal pro-B-type natriuretic peptide, troponin T, and troponin I, and the possible influence due to sampling site chosen, postmortem interval elapsed, and cardiopulmonary resuscitation attempts. Comparisons were performed between antemortem serum levels of these markers and postmortem levels measured in pericardial fluid and postmortem serum samples obtained from different sampling sites (n=16). Levels of these markers were also compared in cases characterized by various postmortem intervals (n=48, consisting of 24 ischemic heart disease cases and 24 controls) as well as in cases with and without cardiopulmonary resuscitation (n=22, consisting of 14 cases of hanging and 8 cases of drug intoxication). Our results indicate that N-terminal pro-B-type natriuretic peptide, troponin T, and troponin I values determined in postmortem serum from femoral blood (collected up to 24h after death) do not differ significantly from those measured in venous blood antemortem serum samples (collected at the upper limbs). In addition, our results reveal that the time elapsed after death should always be taken into consideration when cardiac troponins are measured in postmortem samples. Lastly, our findings reveal the absence of statistically significant differences between levels of the tested biomarkers (in postmortem serum from femoral blood) in cases without cardiopulmonary resuscitation compared to cases with cardiopulmonary resuscitation (at least for postmortem intervals up to 24h).

Elevation of NT-proBNP and cardiac troponins in sepsis-related deaths: a forensic perspective

In the present study, the levels of NT-proBNP, troponin T, and troponin I were measured in postmortem serum from femoral blood in a series of sepsis-related fatalities that had undergone forensic autopsies. We aimed to assess whether a possible increase in the concentrations of these biomarkers was correlated to macroscopic or microscopic observations that suggest myocardial damage or cardiac dysfunction. Two study groups were retrospectively formed, a sepsis-related fatalities group and a control group. Both groups consisted of 16 forensic autopsy cases. Unenhanced computed tomography scan, autopsy, histological, toxicological, microbiological, and biochemical analyses were performed for all cases in both groups. Levels of procalcitonin, C-reactive protein, NT-proBNP, troponin T, and troponin I were systematically measured in postmortem serum from femoral blood. The preliminary results suggest that the postmortem serum troponin I, troponin T, and NT-proBNP levels are increased in sepsis-related deaths in the absence of any relevant coronary artery disease, myocardial ischemia, or signs of heart failure. These findings corroborate clinical data from previous studies pertaining to the usefulness of troponins and natriuretic peptides as indicators of toxic and inflammatory damage to the heart in cases of severe sepsis and septic shock without concomitant underlying coronary syndromes.

Cardiac troponin T determination by a highly sensitive assay in postmortem serum and pericardial fluid

PURPOSE

The main objective of this study was to test, for the first time, a highly sensitive cardiac troponin T (cTnThs) assay in postmortem serum and pericardial fluid and to evaluate cardiac troponin T (cTnT) levels and their stability after death at different postmortem intervals, in an attempt to determine the viability of the cTnThs assay in the postmortem diagnosis of the cause of death.

METHODS

cTnT levels were determined in serum and pericardial fluid samples taken from 58 cadavers at known postmortem intervals, whose causes of death were categorized into the following groups: (1) sudden cardiac deaths, (2) multiple trauma, (3) mechanical asphyxia, and (4) other natural deaths. cTnT was determined by inmunoassay, using the Troponin T highly sensitive STAT assay (Roche(®)).

RESULTS

Average cTnT levels measured by a highly sensitive assay in postmortem serum were markedly higher than clinical serum levels. Moreover, similar results, higher cTnT levels in postmortem pericardial fluid, were obtained when compared to levels found in pericardial fluid taken from two living patients during coronary artery bypass surgery. cTnT levels in both postmortem fluids remained stable for up to 34 h after death. No differences in cTnT levels in either postmortem fluid by sex and age were detected. Levels of cTnT found in pericardial fluid in the other natural deaths group were significantly lower than the cTnT levels found in that postmortem fluid from any of the other causes of death groups.

CONCLUSION

It is therefore reasonable to conclude that determination of cTnT by a highly sensitive assay in pericardial fluid can provide forensic pathologists with a complementary test to the diagnosis of cause of death.

The effect of elapsed time on cardiac troponin-T (cTnT) degradation and its dependency on the cause of death

PURPOSE

The aim of the present study is to evaluate the effect of elapsed time on cardiac troponin-T degradation and its dependency on the cause of death.

METHODS

The cases included in this study were divided into six groups depending upon the cause of death without any prior history of disease that died in the hospital and their exact time of death was known. The analysis involves extraction of the protein, separation by denaturing gel electrophoresis and visualization by Western blot.

RESULTS

Western blot data shows the rate of degradation of cTnT into lower molecular weight fragments with respect to time. In cases of control group the greatest amount of protein breakdown was observed within the first 64 h while in MI cases within first 6 h, the original band of cTnT (42 kDa) decreased markedly into seven major fragments, with 25 kDa & 20 kDa fragments being the most prominent. In burn group, at 41.40 h blot shows maximum fragmentation. In electrocution group the greatest amount of protein breakdown was observed within the first 50 Hrs. Within asphyxia cases, the original band of cTnT (42 kDa) decreased markedly into many major and minor fragments which continues up to 210 Hrs while the original band of cTnT (42 kDa) in poisoning cases decreased markedly into many major & minor fragments up to 140 h but after it blot shows only intact protein of very less intensity with few minor fragments.

CONCLUSION

It can be observed that in case of death due to MI, the intact cTnI fragmented at a much faster rate than in burn, electrocution, control, poisoning and asphyxia group. Thus, the rate of fragmentation of intact cTnT into lower molecular weight fragments depends upon the cause of death.