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

HIF-1α expression by immunohistochemistry and mRNA-210 levels by real time polymerase chain reaction in post-mortem cardiac tissues: A pilot study

INTRODUCTION

The postmortem diagnosis of acute myocardial ischemia (AMI) represents a challenging issue in forensic practice. Immunohistochemical studies and gene expression studies are becoming a promising field of research in forensic pathology. The present study aims to evaluate HIF-1α expression through immunohistochemistry (IHC), and mRNA-210 level using real-time polymerase chain reaction (RT-PCR), in order to define if HIF-1α and mRNA-210 in post-mortem myocardium could be adopted in the diagnosis of AMI.

MATERIALS AND METHODS

Thirty-five deceased individuals, who underwent forensic autopsy at the Legal Medicine Service of the University of Parma, between 2010 and 2018, were investigated. The cohort was divided into two groups according to the cause of death (sudden deaths caused by AMI vs control cases). Cardiac specimens were collected during autopsy, then samples were processed for morphological evaluation using haematoxylin-eosin staining, for IHC, and for RT-PCR. HIF-1α expression and mRNA-210 levels were investigated.

RESULTS

Statistical evaluation demonstrated statistically significant differences in terms of number of IHC positive vessels, leukocytes, and cardiomyocytes between the two groups. Moreover, in the majority of cases, immunostaining positivity was observed only in myocardial and subendocardial samples. With reference to mRNA-210, the difference between the two groups proved to be statistically significant.

CONCLUSIONS

The present study indicates that HIF-1α and mRNA-210 in post-mortem cardiac specimens could represent appropriate biomarkers in the diagnosis of AMI. The current study was primarily limited by the scarcity of the cohort, so further research is required to confirm these preliminary observations.

The amino acid metabolomics signature of differentiating myocardial infarction from strangulation death in mice models

This study differentiates myocardial infarction (MI) and strangulation death (STR) from the perspective of amino acid metabolism. In this study, MI mice model via subcutaneous injection of isoproterenol and STR mice model by neck strangulation were constructed, and were randomly divided into control (CON), STR, mild MI (MMI), and severe MI (SMI) groups. The metabolomics profiles were obtained by liquid chromatography-mass spectrometry (LC-MS)-based untargeted metabolomics. Principal component analysis, partial least squares-discriminant analysis, volcano plots, and heatmap were used for discrepancy metabolomics analysis. Pathway enrichment analysis was performed and the expression of proteins related to metabolomics was detected using immunohistochemical and western blot methods. Differential metabolites and metabolite pathways were screened. In addition, we found the expression of PPM1K was significantly reduced in the MI group, but the expression of p-mTOR and p-S6K1 were significantly increased (all P < 0.05), especially in the SMI group (P < 0.01). The expression of Cyt-C was significantly increased in each group compared with the CON group, especially in the STR group (all P < 0.01), and the expression of AMPKα1 was significantly increased in the STR group (all P < 0.01). Our study for the first time revealed significant differences in amino acid metabolism between STR and MI.

Characterization of global research trends and prospects on sudden coronary death: A literature visualization analysis

Background

Sudden coronary death is a major global public health issue that has a significant impact on both individuals and society. Nowadays, scholars are active in sudden coronary death all over the world. However, no relevant bibliometric studies have been published. Here, we aim to gain a better understanding the current state of research and to explore potential new research directions through bibliometric analysis.

Methods

Articles and reviews on sudden coronary death from 2012 to 2023 were retrieved from the Web of Science Core Collection (WoSCC). The topic search was conducted using the following keywords: ((("sudden cardiac death" OR "sudden death") AND (coronary OR "myocardial infarction")) OR "sudden coronary death"). Knowledge maps of authors, countries, institutions, journals, keywords, and citations were conducted by CiteSpace. Publication dynamics, hotspots, and frontiers were analyzed independently by authors.

Results

A total of 2914 articles were identified from January 1, 2012 to June 20, 2023. The USA (n = 972) contributed the greatest absolute productivity and UK (centrality = 0.13) built a robust global collaboration. Harvard University was the institution with the highest number of publications (n = 143). Huikuri HV and Junttila MJ were the most published authors who devoted to searching for biomarkers of sudden coronary death. American Journal of Cardiology was the journal with the most publications, and Circulation was the most cited journal. Left ventricular ejection fraction, society, inflammation, and fractional flow reserve became novel burst words that lasted until 2023. Research on etiology and pathology, role of early risk factors in risk stratification, potential predictive biomarkers and novel measurement methods for the prevention and management of sudden coronary death were identified as the research hotspots and frontiers.

Conclusion

Our knowledge and understanding of sudden coronary death have significantly improved. Ongoing efforts should focus on the various etiologies and pathologies of sudden coronary death. Furthermore, a novel sudden coronary death risk model, large-scale population studies, and the rational use of multiple indicators to individualize the assessment of sudden coronary death and other risk factors are other emerging research trends.

CircSMARCC1 and CircLRBA are potential biomarkers in forensic postmortem diagnosis of acute myocardial infarction

Postmortem diagnosis of acute myocardial infarction (AMI), especially early AMI, is a challenge for forensic scientists. Circular RNAs (circRNA) are a unique type of RNA with a closed loop structure and more stability, compared with linear RNA. We aimed at evaluating whether circRNAs are ideal postmortem diagnostic markers for AMI. We employed bioinformatics methods to screen for target circRNAs. Divergent and convergent primers were used to confirm the loop structure. Ribonuclease R (RNaseR) digestion and artificial simulated room temperature test were performed to evaluate the stability of circRNAs. Furthermore, RT-PCR analysis was performed to assess the expressions of target circRNAs in a mouse model of AMI and in autopsy cases, while the diagnostic significance of circRNAs was evaluated by the receiver-operator characteristic (ROC) curve. The bioinformatics analysis screened out circSMARCC1 and circLRBA as target circRNAs. Agarose gel electrophoresis revealed the loop structure of target circRNAs. RNaseR digestion and the artificial simulated room temperature test showed that the stability of circRNAs was good. In mouse AMI model, circSMARCC1 levels were elevated while circLRBA levels were suppressed. Finally, in forensic autopsy cases, circSMARCC1 levels were significantly elevated, while circLRBA levels were significantly suppressed in the MI and early-MI group, relative to the normal control group. The ROC curve analysis showed that both circSMARCC1 and circLRBA can distinguish between AMI and normal control cases. Futher, a combination of the two circRNAs can increase the diagnostic efficacy of AMI. Thus, circSMARCC1 and circLRBA are potential biomarkers for postmortem diagnosis of AMI.

Research Progress on Molecular Markers Related to Unexplained Sudden Cardiac Death and Its Forensic Application

Routine pathological examination of unexplained sudden cardiac death (USCD) lacks significant morphological characteristics. In the field of forensic medicine, molecular biology methods have been used to find the cause of death by detecting genes and research related to the mechanism of sudden cardiac death has been carried out. From the molecular pathology point of view, the application of multiple levels of biomarkers to resolve the causes of USCD has already shown potential and provides an important path for forensic identification of USCD. This article reviews the latest research progress on USCD-related genes, RNA, proteins and USCD, and summarizes forensic application.

Metabolomics improves the histopathological diagnosis of asphyxial deaths: an animal proof-of-concept model

The diagnosis of mechanical asphyxia remains one of the most difficult issues in forensic pathology. Asphyxia ultimately results in cardiac arrest (CA) and, as there are no specific markers, the differential diagnosis of primitive CA and CA secondary to asphyxiation relies on circumstantial details and on the pathologist experience, lacking objective evidence. Histological examination is currently considered the gold standard for CA post-mortem diagnosis. Here we present the comparative results of histopathology versus those previously obtained by ¹H nuclear magnetic resonance (NMR) metabolomics in a swine model, originally designed for clinical purposes, exposed to two different CA causes, namely ventricular fibrillation and asphyxia. While heart and brain microscopical analysis could identify the damage induced by CA without providing any additional information on the CA cause, metabolomics allowed the identification of clearly different profiles between the two groups and showed major differences between asphyxiated animals with good and poor outcomes. Minute-by-minute plasma sampling allowed to associate these modifications to the pre-arrest asphyxial phase showing a clear correlation to the cellular effect of mechanical asphyxia reproduced in the experiment. The results suggest that metabolomics provides additional evidence beyond that obtained by histology and immunohistochemistry in the differential diagnosis of CA.

CircSLC8A1 and circNFIX can be used as auxiliary diagnostic markers for sudden cardiac death caused by acute ischemic heart disease

Sudden cardiac death (SCD) caused by acute ischemic heart disease (IHD) is a major cause of sudden death worldwide. Circular RNAs (circRNAs) are abundant in the heart and play important roles in cardiovascular diseases, but the role of circRNAs as biomarkers in the forensic diagnosis of SCD caused by acute IHD remains poorly characterized. To investigate the potential of two heart-enriched circRNAs, circNFIX and circSLC8A1, we explored the expression of these two circRNAs in different kinds of commonly used IHD models, and further verified their expressions in forensic autopsy cases. The results from both the IHD rat and H9c2 cell models revealed that circSlc8a1 level was upregulated, while the circNfix level was elevated in the early stage of ischemia and subsequently downregulated. The time-dependent expression patterns of the two circRNAs suggested their potential as SCD biomarkers. In autopsy cases, the results showed that the expression of these two circRNAs in the myocardium with acute IHD-related SCDs corresponded to the observations in the ischemic models. Further analysis related to myocardial ischemia indicated that circSLC8A1 showed high sensitivity and specificity for myocardial infarction and was positively correlated with creatine kinase MB in pericardial fluid. Downregulated circNFIX level could indicate the ischemic myocardial damage, and it was negatively correlated with the coronary artery stenosis grade. The combination of circSLC8A1 and circNFIX had better performance to discriminate IHD-related SCDs. The results suggested that circSLC8A1 and circNFIX may be used as auxiliary diagnostic markers for SCD caused by acute IHD in forensic medicine.