Postmortem cardiac troponin T levels in the blood and pericardial fluid. Part 2: Analysis for application in the diagnosis of sudden cardiac death with regard to pathology

Characteristics of deceased subjects transported to a postmortem imaging center due to unusual death related to epilepsy

OBJECTIVE

Patients with epilepsy have high risk of experiencing uncommon causes of death. This study aimed to evaluate patients who underwent unusual deaths related to epilepsy and identify factors that may contribute to these deaths and may also include sudden unexpected death in epilepsy (SUDEP).

METHODS

We analyzed 5291 cases in which a postmortem imaging (PMI) study was performed using plane CT, because of an unexplained death. A rapid troponin T assay was performed using peripheral blood samples. Clinical information including the cause of death suspected by the attending physician, body position, place of death, medical history, and antiseizure medications was evaluated.

RESULTS

A total of 132 (2.6%) patients had an obvious history of epilepsy, while 5159 individuals had no history of epilepsy (97.4%). Cerebrovascular disease was the cause of death in 1.6% of patients in the group with epilepsy, and this was significantly lower than that in the non-epilepsy group. However, drowning was significantly higher (9.1% vs. 4.4%). Unspecified cause of death was significantly more frequent in the epilepsy group (78.0% vs. 57.8%). Furthermore, the proportion of patients who demonstrated elevation of troponin T levels without prior cardiac disease was significantly higher in the epilepsy group (37.9% vs. 31.1%). At discovery of death, prone position was dominant (30.3%), with deaths occurring most commonly in the bedroom (49.2%). No antiseizure medication had been prescribed in 12% of cases, while 29.5% of patients were taking multiple antiseizure medications.

SIGNIFICANCE

The prevalence of epilepsy in individuals experiencing unusual death was higher than in the general population. Despite PMI studies, no definitive cause of death was identified in a significant proportion of cases. The high troponin T levels may be explained by long intervals between death and examination or by higher incidence of myocardial damage at the time of death.

PLAIN LANGUAGE SUMMARY

This study investigated unusual deaths in epilepsy patients, analyzing 5291 postmortem imaging cases. The results showed that 132 cases (2.6%) had a clear history of epilepsy. In these cases, only 22% cases were explained after postmortem examination, which is less than in non-epilepsy group (42.2%). Cerebrovascular disease was less common in the epilepsy group, while drowning was more common. Elevated troponin T levels, which suggest possibility of myocardial damage or long intervals between death and examination, were also more frequent in the epilepsy group compared to non-epilepsy group.

Usefulness of Heart-Type Fatty Acid-Binding Protein Measurement in Postmortem Urine Specimens

ABSTRACT

Heart-type fatty acid-binding protein (HFABP) is a 15-kDa substance reported to pass through the renal tubules and be renally excreted. Therefore, it is possible that its concentration in the urine collected postmortem may reflect antemortem blood levels. We measured the postmortem urine concentration of HFABP in 94 forensic autopsy cases and compared it between acute myocardial infarction (AMI), sepsis, heat stroke cases, and asphyxia cases as control cases to examine its diagnostic validity. Kidney tissue collected at autopsy was immunostained with antibodies against HFABP to evaluate the correlation with the urinary measurements. Urinary HFABP was significantly higher in AMI, sepsis, and heat stroke cases than in asphyxia cases. Quantitative immunostaining results showed no significant differences between any 2 groups. The usefulness of kidney immunostaining for HFABP in elucidating the cause of death was low. Two reasons may explain the lack of significant differences in kidney immunostaining: nonspecific leakage of tubular epithelial HFABP into the tubules because of postmortem changes and oliguria due to dehydration caused by heat stroke. In conclusion, the measurement of urinary HFABP may be useful in elucidating the cause of death; however, the kidney HFABP immunostaining was not significantly different from AMI.

Postmortem biochemical analysis of soluble ST2 in the pericardial fluid of patients with sudden cardiac death caused by ischemic heart disease: a pilot study

Soluble growth stimulation expressed gene 2 protein (sST2) is a myocardial protein induced by biomechanical stress. sST2 is widely present in the serum of patients with heart failure and is recommended as an important indicator to predict adverse outcomes in these patients. However, no postmortem biochemical analysis of sST2 in forensic practice has been reported. The present pilot study aimed to investigate the expression of sST2 in the pericardial fluid of patients with sudden cardiac death (SCD) caused by ischemic heart disease (IHD). In addition, to explore the relationship of sST2 with CK-MB, cTnT, and NT-proBNP, which have been proven to be auxiliary biomarkers for the diagnosis of SCD, we analyzed CK-MB, cTnT, NT-proBNP, and sST2 levels in twenty-one pericardial fluid samples from the Center of Forensic Investigation, China Medical University, with a Roche cobas e 411 electrochemiluminescence automatic immunoassay system and ST2/IL-33R Valukine™ enzyme-linked immunosorbent assay kit. The levels of sST2 in the pericardial fluid of patients with SCD caused by IHD were significantly increased (P < 0.01) and positively correlated with CK-MB and NT-proBNP (P < 0.0001). Receiver operating characteristic curve analysis indicated that the combined measurement of sST2 and NT-proBNP has a higher diagnostic value for SCD caused by IHD than the measurement of either indicator alone. This study preliminarily demonstrated that sST2 in the pericardial fluid was significantly increased in patients with SCD caused by IHD and might be used as a novel auxiliary biomarker for postmortem diagnosis of SCD in forensic practice.

Postmortem pericardial fluid sLOX-1 levels and LOX-1 immunostaining in forensic specimens: Relation to cause of death

Lectin-like oxidized LDL receptor-1 (LOX-1) is the endothelial receptor for oxidized LDL. This receptor's extracellular domain is released into the blood as soluble LOX-1 (sLOX-1) and has been linked to ischemic heart disease (IHD), cerebrovascular diseases (CVDs), obesity, and diabetes. We recently reported that sLOX-1 fluid levels in postmortem pericardial fluid were comparable to clinical values in live patients and that significant increases in sLOX-1 were observed in patients with IHD. However, postmortem serum and urine sLOX-1 levels were higher than serum levels in living patients. Here, we conducted LOX-1 immunostaining in forensic specimens (aorta and heart) and evaluated pericardial fluid sLOX-1 in 221 medicolegal autopsy cases (67 IHD, 11 CVD, 17 inflammatory diseases, and 126 control cases) with a postmortem interval < 72 h to assess the diagnostic efficiency of postmortem pericardial fluid sLOX-1. Furthermore, we evaluated the relationships between pericardial fluid sLOX-1 and body mass index (BMI), blood HbA1c, serum C-reactive protein (CRP), high-density lipoprotein cholesterol (HDL-C), and low-density-lipoprotein cholesterol (LDL-C). LOX-1 immunostaining positivity was found in the aortic intima. Pericardial fluid sLOX-1 levels were considerably higher in patients with IHD and CVD. However, there were no significant differences in patients with inflammatory diseases and controls. No associations between pericardial fluid sLOX-1 and BMI, HbA1c, CRP, HDL-C, or LDL-C were found. These results indicate sLOX-1 utility in the postmortem diagnosis of IHD and CVD.

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.

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 role of postmortem CK-MB in cardiac death: a systematic review and meta-analysis

Biochemical analysis of creatine kinase MB (CK-MB), which is a biomarker of myocardial damage, is used as a potential adjunct test in clinical and forensic medicine. However, there is no previous meta-analysis that summarizes the diagnostic value of postmortem biochemical analysis of CK-MB in cardiac death. The purpose of this study was to perform a systematic literature review and meta-analysis of postmortem CK-MB in cardiac death for forensic work. Six online databases, including PubMed, Embase, Cochrane Library, the China National Knowledge Infrastructure (CNKI), the China Biomedical Literature Database (CBM), and Wanfang Data, were used to search for related studies. The quality of the included literature was assessed according to the Newcastle-Ottawa Quality Assessment Scale (NOS). The meta-analysis was performed by Review Manager version 5.3 software to investigate the diagnostic role of postmortem CK-MB in cardiac death, especially in myocardial infarction. Sixteen pieces of related literature were identified, all of which were considered high quality. The results of the meta-analysis revealed that the postmortem CK-MB level in the pericardial fluid was significantly higher in the cardiac death group with a standard mean difference (SMD) = 0.63, 95% confidence interval (CI) = 0.09~1.17, p = 0.02. This was also the result in the myocardial infarction group (SMD = 0.83, 95% CI = 0.10~1.56, p = 0.03). No significant difference in CK-MB was found in serum for cardiac death (SMD = -0.31, 95% CI = -0.85~0.24, p = 0.27) or myocardial infarction (SMD = -0.10, 95% CI = -0.69~0.49, p = 0.74). The postmortem biochemical analysis of CK-MB in the pericardial fluid can be used as an auxiliary method in the postmortem diagnosis of cardiac death, along with autopsy and histological investigation.

Combined determination of B-type natriuretic peptide and high-sensitivity troponin I in the postmortem diagnosis of cardiac disease

Cardiac disease is the most common cause of sudden death in Western countries. It is known that high-sensitivity troponin I (hs-cTnI), widely used for detection of myocardial injury, is a sensitive biochemical marker. B-type natriuretic peptide (BNP) is a reliable tool for diagnosing heart failure, and for establishing prognosis or disease severity. We aimed to evaluate the diagnostic efficacy of the postmortem determination of BNP in serum alone or in addition to other biomarkers, such as hs-cTnI and MB isoenzyme of creatine kinase (CK-MB), to ascertain whether its determination improves the post-mortem diagnosis of heart failure-associated causes of death. This study involved 133 cadavers with a mean age of 58.2 (± 17.6) years and a mean postmortem interval of 12.8 (±6.6) h. Cases were assigned into two diagnostic groups, according to the cause of death: cardiac deaths (N = 62) and control (N = 71). In the cardiac group, two categories were established according to morphological features of the heart: 'ischemic deaths' (N = 39), and 'congestive heart' (n = 23). Both hs-cTnI and BNP were useful in diagnosing cardiac deaths, whereas CK-MB did not have any diagnostic relevance. hs-cTnI is higher in cases which acute ischemia as the principal pathology, while the presence of high BNP values is significantly related with chronic cardiac situations with significant ventricular overload. Our findings show that postmortem determination of hs-cTnI and BNP provides valuable information; hs-cTnI is useful for diagnosis of cardiac deaths, mainly with ischemic implications, and BNP gave better results for the diagnosis of congestive heart failure.

mRNA expression patterns in human myocardial tissue, pericardial fluid and blood, and its contribution to the diagnosis of cause of death

Gene expression has become an interesting research area in forensic pathology to investigate the process of death at the molecular level. The aims of this study were to analyze changes in gene expression patterns in relation to the cause of death, and to propose new molecular markers of myocardial ischemia of potential use for the postmortem diagnosis of early ischemic heart damage in cases of sudden cardiac death (SCD). We determined mRNA levels of five proteins related with ischemic myocardial damage and repair - TNNI3, MYL3, TGFB1, MMP9 and VEGFA - in specific sites of the myocardium, blood and pericardial fluid in samples from 30 cadavers with different causes of death (SCD, multiple trauma, mechanical asphyxia, and other natural deaths). TNNI3 expression in blood, and MMP9 expression in pericardial fluid, were significantly higher when the cause of death was mechanical asphyxia, probably because of the more sensitive response of these proteins to acute systemic hypoxia/ischemia. Specifically, among SCD cases, increased MYL3, VEGFA and MMP9 values in the anterior wall of the right ventricle were found when the confirmed cause of death was acute myocardial infarction (AMI). Higher TGFB1 expression was found in the interventricular septum when AMI was not the cause of death, most likely as a reflection of the short duration of ischemia. Molecular biology techniques can provide complementary tools for the forensic diagnosis of early ischemic myocardial damage and AMI, and may make it possible to determine the duration and severity of myocardial ischemia.

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.

BNP and NT-proBNP as Diagnostic Biomarkers for Cardiac Dysfunction in Both Clinical and Forensic Medicine

Currently, brain natriuretic peptide (BNP) and N-terminal proBNP (NT-proBNP) are widely used as diagnostic biomarkers for heart failure (HF) and cardiac dysfunction in clinical medicine. They are also used as postmortem biomarkers reflecting cardiac function of the deceased before death in forensic medicine. Several previous studies have reviewed BNP and NT-proBNP in clinical medicine, however, few articles have reviewed their application in forensic medicine. The present article reviews the biological features, the research and application status, and the future research prospects of BNP and NT-proBNP in both clinical medicine and forensic medicine, thereby providing valuable assistance for clinicians and forensic pathologists.

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.

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.

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).

Astrocytic clasmatodendrosis in the cerebral cortex of methamphetamine abusers

Postmortem investigation of methamphetamine (MA) abuse is an important task in forensic pathology. The present study investigated morphological changes in the astrocytes in the parietal cerebral cortex of MA abusers. Glial fibrillary acidic protein immunoreactivity in the cerebral cortex was examined in forensic autopsy cases for MA-detected group and control group. Clasmatodendrotic astrocytes (including those with swollen cell bodies and disintegrating distal processes) were frequently observed in the cerebral cortex of MA abusers. Quantitative analysis using a colour image processor showed a concomitant increase in the astrocyte area and astrocyte-to-vessel area ratio (size and number of astrocytes) in the grey matter in acute MA fatality and other MA-involved cases, although the astrocyte area (size) was also increased in cases of asphyxiation. The total astrocyte area (size) in the white matter was significantly higher in MA fatalities and asphyxia than in the other groups involving MA abusers. Those indices were independent of blood MA level, age, sex, survival or postmortem time. These observations suggest the increasing number and hypertrophic changes of astrocytes in the grey matter in MA abusers can be the outcome of long-term abuse, while disintegrating distal processes may exist only in acute fatal MA intoxication.

Use of Cardiac Injury Markers in the Postmortem Diagnosis of Sudden Cardiac Death

In the daily practice of forensic pathology, sudden cardiac death (SCD) is a diagnostic challenge. Our aim was to determine the usefulness of blood biomarkers [creatine kinase CK-MB, myoglobin, troponins I and T (cTn-I and T), and lactate dehydrogenase] measured by immunoassay technique, in the postmortem diagnosis of SCD. Two groups were compared, 20 corpses with SCD and 8 controls. Statistical significance was determined by variance analysis procedures, with a post hoc Tukey multiple range test for comparison of means (p < 0.05). SCD cases showed significantly higher levels (p < 0.05) of cTn-T and cTn-I compared to the control group. Although only cases within the first 8 h of postmortem interval were included, and the control group consisted mainly of violent death cases, our results suggest that blood troponin levels may be useful to support a diagnosis of SCD.

Decreased mRNA levels of cardiac Cx43 and ZO1 in sudden cardiac death related to coronary atherosclerosis: a pilot study

Sudden cardiac death (SCD) is the most frequent cause of sudden unexplained death in forensic practice. The most common cause of SCD is coronary artery disease related to coronary atherosclerosis. Previous study suggested the possible application of connexin 43 (Cx43) and zonula occludens-1 (ZO1) immunostaining in the early diagnosis of myocardial ischemia. However, there appears to be insufficient data with regard to their mRNA levels. The present study investigated the cardiac mRNA levels of Cx43 and ZO1, using forensic autopsy materials consisting of 41 control cases without any disease or structural abnormality of the heart (group 1), 32 deaths due to acute ischemic heart disease related to coronary atherosclerosis without apparent myocardial necrosis (group 2), and 29 traumatic deaths with coronary atherosclerosis (group 3). Ten candidate reference genes were evaluated in the left ventricles of 10 forensic autopsy cases. EEF1A1, PPIA, TPT1, and RPL13A were identified as the most stable reference genes. Using these validated reference genes, mRNA levels of Cx43 and ZO1 were examined in the bilateral ventricles and atria of the heart. Relative mRNA quantification demonstrated decreased calibrated normalized relative quantity (CNRQ) values of Cx43 and ZO1 in bilateral ventricles of group 2. When using one conventional reference gene (GAPDH or ACTB) for normalization, nearly no difference was detected among the three groups. These findings indicate that ventricular gap junction remodeling may be a key contributor to rhythm disturbances. Analysis of cardiac Cx43 and ZO1 using real-time PCR is useful in diagnosis of SCD, and validation of reference genes is crucial.

Cardiac dilatation index as an indicator of terminal central congestion evaluated using postmortem CT and forensic autopsy data

Previous studies demonstrated possible application of postmortem quantitative CT data analysis of the heart and lung in situ to investigate terminal cardiopulmonary pathophysiology. The present study analyzed virtual CT morphometric and autopsy data of the heart to investigate terminal central congestion in forensic autopsy cases (n=113, within 3 days postmortem); the virtual total heart weight in situ was estimated using CT morphometry, and the difference from and ratio to the measured weight at autopsy were calculated as indicators of heart blood pooling and the cardiac dilatation index (CDI) before dissection, respectively. There were substantial differences between the estimated heart blood pooling in situ and volume recovered at autopsy, including a characteristic decrease in drowning, alcohol/sedative-hypnotic intoxication and sudden cardiac death (SCD), possibly due to blood redistribution after thoracic dissection. The estimated in situ heart blood pool and CDI values were higher in SCD but lower in fatal hemorrhage and hemopericardium, as well as in acute mechanical asphyxiation and hyperthermia (heatstroke). In addition, there was a significant difference in heart blood pooling between mechanical asphyxiation or drowning and SCD. The CDI was significantly lower in fatal hyperthermia (heatstroke) than in drowning, fatal methamphetamine abuse, alcohol/sedative-hypnotic intoxication and SCD. These findings suggest the usefulness of applying the CDI and postmortem heart blood volume in situ as supplementary indicators of terminal central congestion, especially for investigating deaths from hemorrhage, hemopericardium, hyperthermia (heatstroke) and SCD.

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.

Changes in Surface Charge Density of Blood Cells in Fatal Accidental Hypothermia

The objective of this research was to evaluate postmortem changes concerning electric charge of human erythrocytes and thrombocytes in fatal accidental hypothermia. The surface charge density values were determined on the basis of the electrophoretic mobility measurements of the cells conducted at various pH values of electrolyte solution. The surface charge of erythrocyte membranes after fatal accidental hypothermia increased compared to the control group within whole range of experimental pH values. Moreover, a slight shift of the isoelectric point of erythrocyte membranes towards high pH values was observed. The surface charge of thrombocyte membranes in fatal accidental hypothermia decreased at low pH compared to the control group. However, at pH range 4-9, the values increased compared to the control group. The isoelectric point of thrombocyte membranes after fatal accidental hypothermia was slightly shifted towards low pH values compared to the control group. The observed changes are probably connected with the partial destruction and functional changes of the blood cell structure.

Cardiac biomarkers in blood, and pericardial and cerebrospinal fluids of forensic autopsy cases: A reassessment with special regard to postmortem interval

Previous studies suggested possible application of postmortem biochemistry of myocardial biomarkers to the investigation of sudden cardiac death; however, differences from clinical findings should be considered in autopsy materials. The present study involved a comprehensive investigation of cardiac troponin T and I (cTnT and cTnI), and creatine kinase MB (CK-MB) in cardiac and peripheral external iliac venous blood, pericardial fluid (PCF) and cerebrospinal fluid (CSF) for reassessment, with special regard to the estimated postmortem interval in relation to the cause of death, reviewing a large number of forensic autopsy cases (n=1923). These cardiac biomarkers showed cause-of-death- and postmortem-time-dependent differences: blood and PCF levels of each marker were higher in hyperthermia (heatstroke), bathwater drowning and chronic congestive heart disease in cases of postmortem interval (PMI) <12h. After 12h postmortem, these markers were also higher in fatal drug abuse, spontaneous cerebral/subarachnoid bleeding, electrocution and pulmonary embolism. In addition, most other causes of death, including ischemic heart disease, showed substantial elevations, while these markers remained low in acute hemorrhagic death from sharp instrument injury, hypothermia (cold exposure) and sea-/freshwater drowning during PMI of <48h. CSF cTnI and CK-MB showed similar findings. There was no difference between myocardial infarction and other causes of death to be discriminated, including asphyxiation, drowning and fire fatality. These findings are similar to clinical observations in critical ill patients, suggesting that elevated cardiac biomarkers cannot be a specific finding for death from acute ischemic heart disease, but indicate the severity of myocardial injury in postmortem investigation.

Appropriate blood sampling sites for measuring Tg concentrations for forensic diagnosis

Previous studies have reported that thyroglobulin (Tg) concentrations in heart blood are high in cases of asphyxia caused by neck compression such as hanging, strangulation, and throttling and in those with fatal traumatic brain injuries. However, even in cases without these findings presumed to increase the Tg concentration in the previous studies, we previously reported that in some cases the Tg concentration in right heart blood (RHB) and left heart blood (LHB) exceeded the standard value for diagnosis (200 ng/mL) defined in previous studies and the Tg concentration in RHB was significantly higher than that in LHB. In the present study, in our 46 forensic autopsy cases without findings presumed to increase Tg concentration, we separately collected external iliac venous blood (IVB) and external iliac arterial blood (IAB) in addition to RHB and LHB, measured Tg concentrations in RHB, LHB, IVB, and LAB (TRHB, TLHB, TIVB, and TIAB, respectively), and investigated the appropriate blood sampling site for measuring Tg concentrations for forensic diagnosis. TRHB, TLHB, TIVB, and TIAB were 386.3 ± 674.1, 105.8 ± 179.0, 109.2 ± 166.8, and 43.7 ± 90.9 ng/mL, respectively. There were statistically significant differences between TRHB and TLHB, TIVB and TIAB, TRHB and TIVB, and TLHB and TIAB. Tg is more readily diffused by the venous system (RHB, IVB) than by the arterial system (LHB, IAB) because the venous system retains more blood volume after death. Tg is more readily diffused to heart blood (RHB, LHB) than to peripheral blood (IVB, IAB) because of the proximity of the heart to the thyroid gland. Therefore, we conclude that Tg leaks into the vessels around the thyroid gland because of the influences of postmortem changes and subsequently diffuses through the blood after death, and therefore the Tg concentration increases after death. When Tg concentration values are used for forensic diagnosis, it is appropriate to measure them using peripheral arterial blood situated distant from the thyroid gland.

Urea nitrogen, creatinine, and uric acid levels in postmortem serum, vitreous humor, and pericardial fluid

Urea nitrogen, creatinine, and uric acid are relatively stable in postmortem serum and may, therefore, be used for diagnostic purposes when chronic kidney disease and end-stage renal failure are investigated as causes of death. Nevertheless, uncertainties remain in defining the best alternative to postmortem serum for the identification and assessment of significantly decreased kidney function. In this study, we investigated urea nitrogen, creatinine, and uric acid levels in postmortem serum, pericardial fluid, and vitreous humor in a series of medico-legal cases (500 autopsies) with various causes of death. No postmortem interval-related differences were observed in any of the investigated fluids for any analyzed parameter, confirming the biochemical stability of all compounds after death. Data analysis failed to reveal statistically significant differences between postmortem serum and pericardial fluid urea nitrogen, creatinine, and uric acid concentrations. Conversely, statistically significant differences were observed in all analyzed biomarkers between postmortem serum and vitreous humor levels, with lower concentrations of all markers measured in vitreous. The results of this study suggest that, in order to estimate as accurately as possible blood analyte concentrations at the time of death, pericardial fluid should be preferred to vitreous humor.

Forensic molecular pathology: its impacts on routine work, education and training

The major role of forensic pathology is the investigation of human death in relevance to social risk management to determine the cause and process of death, especially in violent and unexpected sudden deaths, which involve social and medicolegal issues of ultimate, personal and public concerns. In addition to the identification of victims and biological materials, forensic molecular pathology contributes to general explanation of the human death process and assessment of individual death on the basis of biological molecular evidence, visualizing dynamic functional changes involved in the dying process that cannot be detected by morphology (pathophysiological or molecular biological vital reactions); the genetic background (genomics), dynamics of gene expression (up-/down-regulation: transcriptomics) and vital phenomena, involving activated biological mediators and degenerative products (proteomics) as well as metabolic deterioration (metabolomics), are detected by DNA analysis, relative quantification of mRNA transcripts using real-time reverse transcription-PCR (RT-PCR), and immunohisto-/immunocytochemistry combined with biochemistry, respectively. Thus, forensic molecular pathology involves the application of omic medical sciences to investigate the genetic basis, and cause and process of death at the biological molecular level in the context of forensic pathology, that is, 'advanced molecular autopsy'. These procedures can be incorporated into routine death investigations as well as guidance, education and training programs in forensic pathology for 'dynamic assessment of the cause and process of death' on the basis of autopsy and laboratory data. Postmortem human data can also contribute to understanding patients' critical conditions in clinical management.

Cardiac troponin T in forensic autopsy cases

The aim of the present study was to describe the findings of postmortem serum and pericardial fluid (PF) cardiac troponin T (cTnT) in various causes of death with regard to the postmortem interval (PMI) and comorbid cardiovascular disease, using 101 autopsy cases with PMI of 8-141 h divided into 9 groups: cardiovascular disease (CVD), other diseases (OD), poisoning (P), asphyxia (A), drowning (D), hypothermia (H), thoracic trauma (TT), other trauma (OT) and fire fatalities (F). The results suggest that cTnT levels may help to differentiate cardiovascular death from poisoning and non-thoracic trauma, as well as to differentiate cardiovascular and other diseases as cause of death from drowning and hypothermia. However, the effect of PMI, unlike comorbid cardiovascular disease, has to be taken into account.

[Cardiac troponin I and the post-mortem diagnosis of myocardial damage]

The aim of this study is to analyse the diagnostic efficacy of post-mortem dosage of cardiac troponine I in cadaver fluids in detection of myocardial damage.

MATERIAL AND METHODS

Our study is prospective, interesting 72 corps autopsied at the Department of Forensic Medicine of the University Hospital Fattouma Bourguiba of Monastir-Tunisia. Were excluded from the study, resuscitated cases and those examined more than 48h after death. Levels of cardiac troponine I were measured in pericardial fluid, cardiac blood and peripheral blood. Statically significant correlations between different variables levels of cardiac troponine I and cardiac damage were studied. Receiver-operator characteristic (ROC) curves were generated and areas under the curves were determined. SPSS (version 12.0) et MedCalc statistical software (version 11.0) were used for statistical analysis. Results were considered to be statistically significant when P<0.05.

MAIN RESULTS

Cardiac troponin I levels in pericardial fluid, cardiac and peripheral blood are correlated significantly between subject with and without observable signs of myocardial damage with a P value respectively at 0.0007, 0.0009 and 0.004. ROC curves analysis showed that the pericardial fluid have the best sensibility and specificity with a cut-off level at 108ng/ml and an area under the curve at 0.925.

CONCLUSION

Our data indicate that cardiac troponin I may be a powerful aid in the diagnosis of myocardial damages. This biological test can be used in triaging sudden deaths before to external examination versus complete autopsy.

Postmortem serum tenascin-C (TN-C) concentrations in forensic autopsy cases: A pilot study

In forensic investigations, autopsy findings offer major clues for the diagnosis of the cause of death. Thus, various clinical biochemical markers are now being tested to complement conventional investigation in the field of forensic medicine. In this study, we focused on tenascin-C (TN-C), a glycoprotein present in the extracellular matrix and expressed in pathological states. We reviewed autopsy cases for a 4-year period (2006-2009) using autopsy records, and analyzed the blood serum concentrations of TN-C and C-reactive protein (CRP) in these cases (N=101). The TN-C levels were relatively higher in the postmortem serum samples than in the samples from healthy individuals, and in cases of head injury, both TN-C and CRP levels were high in the postmortem serum sample. Moreover, high TN-C levels were observed particularly in cases with a long survival period. These findings indicate that postmortem serum TN-C levels may represent a useful tool for identifying the cause of specific fatal traumas.

Sensitivity and specificity of NT-proBNP to detect heart failure at post mortem examination

NT-proBNP, a marker of cardiac failure, has been shown to be stable in post mortem samples. The aim of this study was to assess the accuracy of NT-proBNP to detect heart failure in the forensic setting. One hundred sixty-eight consecutive autopsies were included in the study. NT-proBNP blood concentrations were measured using a chemiluminescent immunoassay kit. Cardiac failure was assessed by three independent forensic experts using macro- and microscopic findings complemented by information about the circumstances of body discovery and the known medical story. Area under the receiving operator curve was of 65.4% (CI 95%, from 57.1 to 73.7). Using a standard cut-off value of >220 pg/mL for NT-proBNP blood concentration, heart failure was detected with a sensitivity of 50.7% and a specificity of 72.6%. NT-proBNP vitreous humor values were well correlated to the ones measured in blood (r (2) = 0.658). Our results showed that NT-proBNP can corroborate the pathological findings in cases of natural death related to heart failure, thus, keeping its diagnostic properties passing from the ante mortem to the post mortem setting. Therefore, biologically inactive polypeptides like NT-proBNP seem to be stable enough to be used in forensic medicine as markers of cardiac failure, taking into account the sensitivity and specificity of the test.