Differential expression of B-type natriuretic peptide between left and right ventricles, with particular regard to sudden cardiac death

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.

Exploring the Potential of Proteome Analysis as a Promising Tool for Evaluation of Sudden Cardiac Death (SCD) in Forensic Settings: A Literature Review

Sudden cardiac death (SCD) represents a global emergency, with a high number of cases affecting all age groups every year. The prevention of these fatal events requires an accurate knowledge of etiology and pathogenesis, which can vary. Autopsy is an indispensable tool in cases of SCD for diagnostic purposes, as well as for judicial and preventive purposes for family members. Despite the completion of all routine post-mortem investigations, it is often complicated for the forensic pathologist to define the triggering cause of these events. The study of the proteome is proving to be extremely promising in the field of human cardiovascular disease. This paper aims to offer a literature review on the study of the proteome in post-mortem cadaveric biological samples obtained from SCD cases. The aim of this work is to outline the state of the art of the scientific advances that protein analysis can offer in the diagnosis of SCD and the limits that various studies have traced up to now. In conclusion, the work defines the future perspectives of this field in SCD, suggesting strategies to overcome the reported limits and improve the diagnostics of these events.

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.

Predictive role of C-reactive protein in sudden death: a meta-analysis of prospective studies

Objective

C-reactive protein (CRP) is a powerful predictor of and risk factor for cardiovascular disease. However, the relationship between CRP and sudden death (SD) is controversial. Therefore, we performed a meta-analysis to evaluate the association between CRP and SD.

Methods

We conducted a comprehensive search of the databases of PubMed, Web of Science, Embase, Cochrane Library, Wanfang, CNKI, China Biology Medicine disc, and Weipu. Two researchers independently screened the literature, extracted data, and evaluated the data quality. The overall effect size was meta-analyzed using Stata software version 12.0 (StataCorp, College Station, TX, USA).

Results

Twelve prospective studies involving 36,646 patients were included in the present meta-analysis. The data revealed that patients with higher CRP concentrations had a greater risk of SD (hazard ratio, 1.19; 95% confidence interval, 1.09–1.29). When the hazard ratio of SD was calculated by multivariate analysis of nine studies, CRP was confirmed to be an independent predictive factor for SD (hazard ratio, 1.05; 95% confidence interval, 1.03–1.07).

Conclusions

This meta-analysis confirmed that CRP is an independent predictor of SD. These results support the recommendation of recording the CRP concentration for risk assessment of SD in clinical practice.

Natriuretic peptides: new challenges — new solutions

Natriuretic peptides (NPs) are one of the most significant biomarkers, the practical use of which increases, and their diagnostic and prognostic value in patients with various chronic noncommunicable diseases is beyond doubt. Since the discovery of these markers, research has been actively carried out to study the biological and pathophysiological roles of NPs in a wide range of diseases, including hypertension and heart failure (HF). These studies showed that A-type and B-type NPs are hormones secreted by the heart in response to pre- or afterload, which prevent high blood pressure and fluid retention. In addition, C-type NPs are produced by the vascular endothelium and act as a local a  mediator with angioprotective properties. Since the NP system is a natural antagonist of the sympathoadrenal and renin-angiotensinaldosterone systems, it is interesting to study novel strategies to use new drug classes for hypertension. These drugs are neprilysin inhibitors, which destroys NPs; their action is to enhance the synthesis of endogenous peptides. Dual angiotensin receptor and neprilysin inhibition is widespread in clinical practice in patients with heart failure with reduced ejection fraction. Neprilysin inhibition has also been shown to be an effective strategy for hypertensive patients. The article discusses the role and value of NP system in  the dia - gnosis of heart failure and blood pressure regulation, and also considers new promising directions for neprilysin inhibition and activation of endogenous NP synthesis.

 

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.

The Expression of BNP, ET-1, and TGF-β1 in Myocardium of Rats with Ventricular Arrhythmias

Ventricular arrhythmia (VA) is a major component of sudden cardiac death (SCD). To investigate the expression of brain natriuretic peptide (BNP), endothelin-1 (ET-1), and transforming growth factor-beta 1 (TGF-β1) during VA, we established a rat model of VA induced by BaCl₂ solution through a microinjector pump. PD142893 (ET-1 receptor blocker) and SB431542 (TGF-β1 receptor type I blocker) were used to explore the effect of ET-1 and TGF-β1 on BNP expression in the myocardium after VA. BNP, ET-1, and TGF-β1 in rat myocardium were assayed by western blot and immunohistochemical staining for proteins, and real-time quantitative polymerase chain reaction for mRNAs. We found increased expression of BNP and ET-1 in rat myocardium that was associated with the duration of VA. However, TGF-β1 protein expression remained unchanged. Such early increases in BNP and ET-1 may be attributed to fatal arrhythmias associated with SCD, suggesting these may be novel biomarkers of this disease. After intraperitoneal injection of PD142893 and SB431542, respectively, BNP was downregulated in the myocardium of the left ventricle; however, this was abrogated by co-application of the two inhibitors. These results suggested that both ET-1 and TGF-β1, by specifically binding to their receptors, might be involved in the myocardial synthesis of BNP during VA in vivo.

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.

AIN-93 Diet as an Alternative Model to Lieber-DeCarli Diet for Alcoholic Cardiomyopathy

BACKGROUND

The Lieber-DeCarli alcoholic liquid diet is a classical method for establishing animal models of alcoholic cardiomyopathy (ACM). No study has reported whether the AIN-93 diet, which is widely used as a standard diet for both long-term and short-term studies with laboratory animals, could be used to construct the ACM animal model. The present study intended to investigate whether the AIN-93 diet could be used to establish a mouse ACM model.

METHODS

Twenty-four C57BL/6 male mice were randomly divided into 4 equally sized groups. In ethanol (EtOH)-fed groups, mice were fed a 4%-EtOH (w/v, 28% of total calories) alcoholic liquid diet of Lieber-DeCarli or the AIN-93 diet for chronic alcohol exposure for 180 days. In control-fed groups, mice were fed with non-EtOH liquid diets with the same calories as EtOH-fed groups. Morphological observations of the hearts and molecular investigation of the brain natriuretic peptide (BNP) were carried out by echocardiography, hematoxylin and eosin (H&E) and immunohistochemistry (IHC) staining, real-time quantitative polymerase chain reaction (qPCR), and enzyme-linked immunosorbent assay.

RESULTS

Echocardiography showed that mice fed with either the 4%-EtOH Lieber-DeCarli diet or the 4%-EtOH AIN-93 diet had dilated ventricles and poor cardiac function. IHC staining of BNP, qPCR of BNP mRNA, and plasma concentration of BNP showed an up-regulated expression in mice fed with both the 4%-EtOH Lieber-DeCarli and 4%-EtOH AIN-93 diets. Less fatty liver was also observed in mice fed the AIN-93 alcoholic diet than those fed the Lieber-DeCarli alcoholic diet.

CONCLUSIONS

The AIN-93 alcoholic liquid diet can be used to establish ACM animal models, as with the conventional Lieber-DeCarli alcoholic liquid diet.

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.

Transcriptional and Epigenetic Regulation of Cardiac Electrophysiology

Spatiotemporal gene expression during cardiac development is a highly regulated process. Activation of key signaling pathways involved in electrophysiological programming, such as Notch and Wnt signaling, occurs in early cardiovascular development and these pathways are reactivated during pathologic remodeling. Direct targets of these signaling pathways have also been associated with inherited arrhythmias such as Brugada syndrome and arrhythmogenic cardiomyopathy. In addition, evidence is emerging from animal models that reactivation of Notch and Wnt signaling during cardiac pathology may predispose to acquired arrhythmias, underscoring the importance of elucidating the transcriptional and epigenetic effects on cardiac gene regulation. Here, we highlight specific examples where gene expression dictates electrophysiological properties in both normal and diseased hearts.