Diagnostic efficacy of biochemical markers in diagnosis post-mortem of ischaemic heart disease

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 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.

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.

Abnormal fatty acid metabolism and ceramide expression may discriminate myocardial infarction from strangulation death: A pilot study

Determining myocardial infarction (MI) and mechanical asphyxia (MA) was one of the most challenging tasks in forensic practice. The present study aimed to investigate the potential of fatty acid (FAs) metabolism, and lipid alterations in determining MI and MA. MA and MI mouse models were constructed, and metabolic profiles were obtained by LC-MS-based untargeted metabolomics. The metabolic alterations were explored using the PCA, OPLS-DA, the Wilcoxon test, and fold change analysis. The contents of lipid droplets (LDs) were detected by the transmission scanning electron microscope and Oil red O staining. The immunohistochemical assay was performed to detect CD36 and dysferlin. The ceramide was assessed by LC-MS. PCA showed considerable differences in the metabolite profiles, and the well-fitting OPLS-DA model was developed to screen differential metabolites. Thereinto, 9 metabolites in the MA were reduced, while metabolites were up- and down-regulated in MI. The increased CD36 suggested that MI and MA could enhance the intake of FAs and disturb energy metabolism. The increased LDs, decreased dysferlin, and increased ceramide (C18:0, C22:0, and C24:0) were observed in MI groups, confirming the lipid deposition. The present study indicated significant differences in myocardial FAs metabolism and lipid alterations between MI and MA, suggesting that FAs metabolism and related proteins, certain ceramide may harbor the potential as biomarkers for discrimination of MI and MA.

Circulating long non-coding RNA TTTY15 and HULC serve as potential novel biomarkers for predicting acute myocardial infarction

INTRODUCTION

Acute myocardial infarction (AMI) is a ubiquitous cardiovascular disease ensuing adverse prognosis caused by myocardial necrosis. Effective and rapid diagnosis of AMI is essential to following treatment in clinical practice while the existed biomarkers have inherent limitations. Consequently, exploration of novel biomarkers is needed. Long noncoding RNA (lncRNA) emerges as the upcoming biomarkers adopted in clinical use, and we aim at investigating the diagnostic power of lncRNA TTTY15 and HULC in AMI patients.

METHOD

We measured lncRNA level in 80 AMI patients and 36 healthy volunteers in discovering cohort and 50 AMI patients and 20 healthy volunteers in verification cohort with quantitative RT-PCR method. Receiver operating characteristic (ROC) analysis was administered to detect the diagnostic power of selected lncRNAs. Regression and correlation analyses were performed to explore the related factors.

RESULTS

ROC analysis reveals the superiority of TTTY15 and HULC as biomarkers against conventional AMI biomarkers CKMB (AUC of TTTY15: 0.915 versus CKMB: 0.768 versus TnT: 0.869); AUC of HULC: 0.905 versus CKMB: 0.768 versus TnT: 0.869). Regression and correlation analysis indicates that TTTY15 and HULC may be one of the contributing factors to AMI and related to accepted risk factors.

CONCLUSION

Our results revealed the diagnostic potency of lncRNA TTTY15 and HULC, and they could also be treated as novel therapeutic targets in AMI therapy, hinting inspiration to the cardiologist in clinical practice.

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.

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.

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.

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.

Mueller-matrix-based polarization imaging and quantitative assessment of optically anisotropic polycrystalline networks

We introduce a Mueller-matrix imaging polarization-based approach for the quantitative digital screening of the polycrystalline structure of fibrillary-based biological tissues in vitro. The morphometric evaluation of histological sections of myocardium was performed utilizing the high-order statistical moments calculated based on the spatial distribution of linear and circular birefringence and dichroism obtained experimentally. We demonstrate that spatial distributions of phase of light and optical anisotropy of scattering inherent to fibrillar networks of myocardium at different necrotic stages can be effectively used as a quantitative marker of stages of myosin fibril degradation. Processing the images of phase of light scattered in biological tissues with high order statistical analysis provides a functional tool for the quantitative characterization of necrotic conditions of the myocardium.

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).

Human Pericardial Fluid Contains Exosomes Enriched with Cardiovascular-Expressed MicroRNAs and Promotes Therapeutic Angiogenesis

The pericardial fluid (PF) is contained in the pericardial sac surrounding the heart. MicroRNA (miRNA) exchange via exosomes (endogenous nanoparticles) contributes to cell-to-cell communication. We investigated the hypotheses that the PF is enriched with miRNAs secreted by the heart and that it mediates vascular responses through exosome exchange of miRNAs. The study was developed using leftover material from aortic valve surgery. We found that in comparison with peripheral plasma, the PF contains exosomes enriched with miRNAs co-expressed in patients' myocardium and vasculature. At a functional level, PF exosomes improved survival, proliferation, and networking of cultured endothelial cells (ECs) and restored the angiogenic capacity of ECs depleted (via Dicer silencing) of their endogenous miRNA content. Moreover, PF exosomes improved post-ischemic blood flow recovery and angiogenesis in mice. Mechanistically, (1) let-7b-5p is proangiogenic and inhibits its target gene, TGFBR1, in ECs; (2) PF exosomes transfer a functional let-7b-5p to ECs, thus reducing their TGFBR1 expression; and (3) let-7b-5p depletion in PF exosomes impairs the angiogenic response to these nanoparticles. Collectively, our data support the concept that PF exosomes orchestrate vascular repair via miRNA transfer.

Potential use of pericardial cTnI, Mg2+ and Ca2+ in the forensic investigation of seawater drowning in Greece: An initial assessment

The investigation of drowning constitutes one of the biggest problems in forensic practice. Elevated cardiac troponin I (cTnI) levels in biological fluids have been associated with myocardial damage, whereas increased Mg²⁺ and Ca²⁺ levels were found in cases of seawater drowning. The aim of this study was to examine the diagnostic utility of postmortem determination of cTnI, Mg²⁺ and Ca²⁺ in the pericardial fluid, in differentiating between cases of seawater drowning related to myocardial injury and those brought about by other causes. This study included 76 cases selected during a 2-year period from medicolegal autopsies. The cases were divided into three groups, according to the cause of death established based on macroscopic and microscopic evidence. The groups were: 1) seawater drowning (n=23), 2) seawater drowning with histological evidence of myocardial infarction (n=28), and 3) myocardial infarction unrelated to drowning (n=25). cTnI was determined with an enzyme immunoassay; Mg²⁺ and Ca²⁺ with standard colorimetric assays. Pericardial cTnI levels were significantly lower in group 1 compared to groups 2 and 3. In contrast, pericardial Mg²⁺ and Ca²⁺ levels were both significantly higher in groups 1 and 2 compared to group 3. Our results suggest that the postmortem determination of pericardial cTnI levels may be useful in detecting previous myocardial damage as a contributory factor in death from seawater drowning and provide independent confirmation of the usefulness of pericardial Mg²⁺ and Ca²⁺ levels for differentiating between seawater drowning and fatal acute myocardial injury unrelated to the former.

Jones-matrix mapping of complex degree of mutual anisotropy of birefringent protein networks during the differentiation of myocardium necrotic changes

The azimuthally stable method of Jones-matrix mapping of histological sections of myocardium tissue biopsy using spatial-frequency selection of the mechanisms of linear and circular birefringence is proposed. Correlation parameter-the complex degree of mutual anisotropy-and its diagnostic application are analytically substantiated. The method of measuring the complex degree of mutual-anisotropy coordinate distributions using spatial filtration of their high- and low-frequency components is developed. The interconnections between such distributions and parameters of linear and circular birefringence of myocardium tissue histological sections are defined. The comparative investigations of coordinate distributions of the complex degree of mutual anisotropy formed by fibrillar networks of myocardium tissues of different necrotic states (dead due to coronary heart disease and acute coronary insufficiency) are performed. The values and ranges of change of the statistical (moments of the first-fourth order) parameters of coordinate distributions of the complex degree of mutual anisotropy are defined. The objective criteria of cause of death differentiation are determined.

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.

Circulating Long Noncoding RNA UCA1 as a Novel Biomarker of Acute Myocardial Infarction

Acute myocardial infarction (AMI) is the most serious cardiovascular disease with high morbidity and mortality. Recent studies have showed that long noncoding RNAs (lnc RNA) play important roles in pathophysiology of cardiovascular diseases, but the investigations are still in their infancy. An lnc RNA named urothelial carcinoma-associated 1 (UCA1) is found in tumors such as bladder cancers and lung cancer. And the UCA1 could be as a predictive biomarker for bladder cancer in urine samples or lung cancer in plasma, respectively. In normal states, UCA1 is specifically expressed in heart of adult, indicating that UCA1 might be as a biomarker for heart diseases such as AMI. To test the speculation, we detect the level of UCA1 in plasma of AMI patients and health control using quantitative reverse transcription-polymerase chain reaction (qRT-PCR). In addition, we also test the level of miR-1 as it is reported to regulate the expression of UCA1. The results show that the level of plasma UCA1 is decreased at the early state of AMI patients and increased at day 3 after AMI. In addition, the UCA1 alteration is inversely associated with the expression of miR-1. These findings indicate that the circulating UCA1 could be used as a promising novel biomarker for the diagnosis and/or prognosis of AMI.

Diagnostic value of cardiac troponin I in postmortem diagnosis of myocardial infarction

Troponin I (cTnI) is a very sensitive biochemical marker for the diagnosis of myocardial infarction (MI). Cardiac troponin (cTnI or cTnT) has nearly absolute myocardial tissue specificity, thereby reflecting even microscopic zones of myocardial necrosis. The aim of this study is to evaluate the pericardial fluid levels of cTnI in medicolegal autopsy cases where patients died of MI and compare them with cases where patients died of other causes. This study included 89 cases selected during a 1-year period from medicolegal autopsies. These were classified into 4 groups: (A) myocardial infarction (n = 28), (B) salt water drowning (n = 20), (C) death resulting from injury in the respiratory system (n = 16), and (D) other causes of death (n = 25), excluding MI. The mean concentrations of cTnI were 1067.03 mg/dL for group A, 546.98 mg/dL for group B, 398.75 mg/dL for group C, and 577.47 mg/dL for group D. In cases with MI (group A), there was a significant difference in the levels of cTnI compared with the other cases. More research needs to be done in order for a cutoff level to be determined.

Can early myocardial infarction-related deaths be diagnosed using postmortem urotensin receptor expression levels?

PURPOSE

Myocardial infarction (MI) is one of the most prevalent causes of sudden adult death. It is difficult to diagnose early MI postmortem because there are no typical or characteristic changes in morphology. In this study, changes in the level of the mRNA for the urotensin receptor (UR) were investigated postmortem to determine the suitability of UR as a biomarker for diagnosis of early MI after death.

METHODS

An MI rat model was developed by injecting rats with isoproterenol (ISO) (lethal dose 850 mg/kg) or normal saline (control group). The hearts of rats in the control and ISO-induced MI groups were harvested at 0, 1, 3, 6, 12, 24, 48, and 72 h (h) postmortem. The hearts were then immediately submerged in 1 mL of RNA stabilization solution and stored at 4 °C for <1 week before RNA extraction. Relative UR expression analysis was performed using the StepOne Plus Real Time PCR System with cDNA synthesized from rat heart.

RESULTS

Postmortem UR mRNA expression was higher in the ISO-induced MI group than in the control group, at both 4 and 20 °C, at all of the time points examined except 72 h postmortem (p < 0.0001). The largest increases were observed at ambient temperature and 6 h postmortem.

CONCLUSIONS

Based on our findings, increased postmortem UR expression could serve as a biomarker to aid diagnosis of early MI.

Laser polarization autofluorescence of endogenous porphyrins of optically anisotropic biological tissues and fluids in diagnostics of necrotic and pathological changes of human organs

This research presents the results of investigation of laser polarization fluorescence of biological layers (histological sections, cytological smears). The polarization structural properties of autofluorescent images of human biological tissues layers and fluids were found and investigated. A model describing the formation of polarizationally heterogeneous images of optically anisotropic biological layers is suggested. On this basis, the practical method of polarization-variable autofluorescence is analytically substantiated and experimentally tested. The efficiency of applying this method to various tasks of medical diagnostics is analyzed: objectification of histological conclusions, defining and differentiating of various forms of cancer (dysplasia--microinvasive cancer) of the cervix uteri, and forensic medical express-differentiation of cause of death. The objective criteria (statistical moments) of differentiation of autofluorescent images of histological sections of myocardium biopsy and endometrium and cytological smears of its mucous tunic are defined. The operational characteristics (sensitivity, specificity, accuracy) of this method are determined concerning the positions of probative medicine, and the clinical efficiency of the technique is demonstrated.

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.

Serum biochemical markers in drowning: diagnostic efficacy of Strontium and other trace elements

The aim of our study was to analyse several serum biochemical markers in order to evaluate the discriminant capacity of trace elements individually and jointly in drowning (seawater drowning and freshwater drowning) and their correlation with age, sex, postmortem interval, time in water and concentrations of the trace elements in the drowning medium. Sixty-seven cases of drowning (53 seawater drownings (SWD); 14 freshwater drownings (FWD) and 73 control cases (other asphyxias, n=44, and other causes of death, n=29) were selected according to the scene, cause and circumstances of death, together with autopsy findings. Serum strontium (Sr), magnesium (Mg), sodium (Na), chloride (Cl), calcium (Ca), iron (Fe), urea, creatinine (Cr) and cardiac Troponine T (cTn-T) were measured in the left ventricle (Lv), right ventricle (Rv) and peripheral blood. Lv-Rv differences for each marker and Sr, Mg, Na, Cl, Ca and Fe concentrations in the drowning medium were determinated. Mean concentrations of Sr, Cl and Mg in both ventricles and peripheral serum and Lv-Rv differences and Ca Lv and Na Rv were significantly higher in cases of drowning than for other causes of death. In SWD, Sr, Mg, Ca, Na and Cl were significantly higher in Lv than in Rv as a result of aspirating water. In contrast, haemodilution is evident from the significantly higher levels of Fe and urea in Rv than in Lv in cases of SWD, and from the higher Mg and Cr levels in Rv in FWD. In the case of SWD, serum levels of Sr are confirmed as the best parameter for diagnosis, although other trace elements may also be useful, such as the serum concentrations of Mg and Cl. In the case of FWD, the joint determination of Sr and other biochemical markers, especially Fe, may increase correct diagnosis.

The role of postmortem cardiac markers in the diagnosis of acute myocardial infarction

Sudden cardiac deaths because of acute myocardial infarction (MI) constitute a significant percentage of the caseload for death investigators, coroners, and forensic pathologists. Clinicians use cardiac markers, highly sensitive and specific for myocardial damage, to screen living patients for acute MI; however, to this point, the utility of these markers in the autopsy setting has not been fully established. The current study included 10 decedents, five who died of acute MI, and five subjects who died of noncardiac disease. Samples of pericardial fluid and blood from multiple sites were tested for creatine kinase, creatinine kinase MB, and troponin-I. Three main conclusions were drawn: the levels of cardiac markers from all patients are significantly higher than the reference range for living patients, there are significant differences in cardiac marker levels between samples from different anatomic locations, and only three cardiac marker/anatomic site combinations were significantly different between the control and study groups.

Postmortem cardiac troponin I and creatine kinase MB levels in the blood and pericardial fluid as markers of myocardial damage in medicolegal autopsy

The present study investigated cardiac troponin I (cTnI) and creatine kinase MB (CK-MB) in the blood and pericardial fluid from medicolegal autopsy cases (n=234, within 48h postmortem) with regard to the cause of death. The cTnI and CK-MB levels in cardiac, peripheral blood and pericardial fluid generally showed a mild and gradual postmortem time-dependent elevation (r=0.231-0.449, P<0.05-0.001). However, postmortem elevation of cTnI was larger for specific causes of death including acute myocardial infarction (AMI), cerebrovascular diseases (CVD), hyperthermia, fatal methamphetamine (MA) abuse and carbon monoxide (CO) intoxication and insignificant for recurrent myocardial infarction (RMI), chronic congestive heart diseases (CHD) and drowning, while that of CK-MB was greater for CO intoxication and insignificant for drowning. Cardiac blood and pericardial cTnI levels were relatively high for AMI, RMI, hyperthermia, MA abuse and CO intoxication, and was low for drowning. Elevated CK-MB level was observed for cardiac blood in asphyxiation and MA abuse cases and for peripheral blood in hyperthermia and MA abuse cases. When the cTnI/CK-MB ratio was estimated, it was independent of postmortem time, and the ratios for cardiac blood and pericardial fluid were significantly higher in cases of AMI, RMI, hyperthermia and CO intoxication but lower in cases of drowning. Elevations of cTnI levels in cardiac blood and pericardial fluid were related to the morphological severity of myocardial damage. These findings suggest that elevated cTnI and CK-MB levels in blood and pericardial fluid are related to ischemic, hypoxic and/or cytotoxic myocardial damage, which are characteristic of the cause of death, although the levels increase after death depending on myocardial damage at the time of death.

Increase in clusterin-containing follicles in the adenohypophysis of drug abusers

The hypothalamic-pituitary-adrenocortical (HPA) system in drug abusers may be affected due to disorders of the hypothalamic dopaminergic system. The present study investigated alterations in the adenohypophysis of middle-aged drug abusers (40-60 years of age), using clusterin-containing mixed cell-follicles as the indicator, in which clusterin (apolipoprotein J) is a multifunctional glycoprotein related to neurodegeneration. The paraffin-embedded adenohypophyses of methamphetamine and psychotropic drug abusers (n = 76) were compared with those of non-abusers (n = 82). The number of follicles was larger in drug abusers independent of the immediate cause of death, although the size was not significantly different. When cell types forming the follicles were immunohistochemically examined, drug abusers showed an increase of prolactin (PRL) cells and gonadotroph cells and a reciprocal decrease of growth hormone cells, suggesting hypofunction of dopaminergic neurons in the hypothalamus, while there was no change in the adrenocorticotropic hormone and thyroid-stimulating hormone cells. These increases of the clusterin-containing follicles and PRL cells in the follicles may be related to the dysfunction of dopaminergic neurons in the hypothalamus of chronic drug abusers and may be useful for investigating drug abuse in forensic casework.

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

Although previous forensic pathological studies have suggested the possible application of cardiac troponins in the diagnosis of myocardial infarction, there appears to be insufficient data with regard to its cardiac pathology. The present study analyzed the heart blood, peripheral blood and pericardial fluid levels of cardiac troponin T (cTnT) in sudden cardiac deaths (n = 96) within 48h postmortem in relation to pathological findings of acute myocardial infarction (AMI, n = 34), recurrent myocardial infarction (RMI, n = 23), ischemic heart disease without any pathological evidence of infarction (IHD, n = 24) and other heart diseases (OHD, n = 15). Control groups (n = 75, survival time <24 h) within 48 h postmortem consisted of asphyxiation (n = 35), drowning (n = 27) and cerebrovascular diseases (n = 13). There was a marked correlation in the cTnT levels between right and left heart blood samples. The pericardial level was usually higher than either heart blood level, and the external iliac venous blood level was the lowest. Although postmortem time-dependent increases in heart and pericardial blood cTnT levels were observed in most groups, they were most evident for AMI and asphyxiation. In the early postmortem period (<12 h) there was no significant difference between AMI or RMI and the other groups except for drowning. After 12 h postmortem, significantly elevated heart blood and pericardial cTnT levels were observed for AMI and RMI showing multiple interstitial hemorrhages and necrosis compared to those with localized eosinophilic changes or patchy interstitial hemorrhages, IHD and OHD. These differences were the smallest for peripheral blood. For sudden cardiac death cases, the difference in cTnT level at each site among the causes of death was independent of gender, age, heart or lung weight and pathologies of affected coronary artery and severity of coronary stenosis. These observations suggest that the elevation in postmortem blood and pericardial cTnT levels in sudden cardiac death may depend on the severity of ischemic myocardial damage including the size and intensity of myocardial lesions involving multiple interstitial hemorrhages and necrosis, and also the postmortem period for heart and pericardial levels.

Postmortem serum protein S100B levels with regard to the cause of death involving brain damage in medicolegal autopsy cases

The protein S100 is an acidic calcium-binding protein, and the subunit S100B is the most abundantly found in the brain. The aim of the present study was a comprehensive analysis of serum S100B levels in medicolegal autopsy cases (within 48 h postmortem, n = 283) including victims with head and non-head injuries and also non-injury fatalities with regard to the cause of death involving brain damage. The serum level was usually higher in the subclavian vein than in the right heart and external iliac vein, and the lowest in the left heart blood, showing no significant postmortem influence. The serum level in the right heart and subclavian vein was markedly higher for acute deaths from head injury and asphyxiation due to neck compression (strangulation and hanging), and moderately and mildly elevated for other blunt and sharp instrument injury cases, respectively. For head injury, the serum levels were lower for subacute deaths than for acute deaths. These observations suggest that the elevation of serum S100B may mainly be caused by leakage following massive brain damage due to injury and cerebral hypoxia/ischemia, and in part by systemic hypoxic/traumatic tissue damage, depending on the survival time.

Postmortem cardiac troponin T levels in the blood and pericardial fluid. Part 1. Analysis with special regard to traumatic causes of death

In forensic pathology, previous studies have suggested the possible application of cardiac troponins in the diagnosis of myocardial infarction. However, there appears to be insufficient practical data on other causes of death. The present study was a comprehensive analysis of the cardiac, peripheral blood and pericardial levels of cardiac troponin T (cTnT) in serial medicolegal autopsy cases (n = 405) with a survival time <24 h and within 48 h postmortem to assess the validity of investigating myocardial damage with special regard to traumatic causes of death. These included blunt and sharp instrument injury (n = 122 and 21, respectively), asphyxiation (n = 35), drowning (n = 27), fire fatalities (n = 94), hyperthermia (n = 13), hypothermia (n = 6), fatal methamphetamine (MA) abuse (n = 12) and carbon monoxide (CO) poisoning (n = 5) in comparison with myocardial infarction (MI, n = 57) and cerebrovascular diseases (n = 13). Cases within 12h postmortem usually showed lower cardiac and pericardial cTnT levels than did those of longer postmortem time of 12-48 h. In the early postmortem period of <12 h, significantly elevated serum cTnT levels were observed for hyperthermia. Thereafter, fatal MA abuse, CO poisoning and MI cases also showed higher levels. However, cTnT remained at lower levels for hypothermia and drowning. The elevation of cTnT was associated with the pathology of advanced myocardial damage involving swelling and liquefactive necrosis. The above-mentioned differences were the smallest for peripheral blood. These findings suggest that elevations in postmortem serum and pericardial cTnT levels depend on the severity of myocardial damage at the time of death and are related to the pathological findings, although postmortem interference should be taken into consideration.