miR-1, miR-499 and miR-208 are sensitive markers to diagnose sudden death due to early acute myocardial infarction

Recent progress in the roles of microRNAs in pulmonary arterial hypertension associated with congenital heart disease

Research on noncoding RNA, particularly microRNAs (miRNAs), is growing rapidly. Advances in genomic technologies have revealed the complex roles of miRNAs in pulmonary arterial hypertension (PAH) associated with congenital heart disease (CHD). It has been demonstrated that the progression of PAH associated with CHD is characterized by particular dysregulation of miRNAs and is related to cardiovascular remodeling, cell death, and right ventricle dysfunction. This review provides a comprehensive overview of the current state of knowledge regarding the involvement of miRNAs in the pathogenesis and progression of PAH associated with CHD. We commence by explaining the process of miRNA synthesis and its mode of action, as well as the role of miRNA in PAH associated with CHD. Moreover, the article delves into current breakthroughs in research, potential clinical implications, and prospects for future investigations. The review provides the insight into novel approaches for diagnosis, prognosis, and therapy of PAH associated with CHD.

Research progress and potential application of microRNA and other non-coding RNAs in forensic medicine

At present, epigenetic markers have been extensively studied in various fields and have a high value in forensic medicine due to their unique mode of inheritance, which does not involve DNA sequence alterations. As an epigenetic phenomenon that plays an important role in gene expression, non-coding RNAs (ncRNAs) act as key factors mediating gene silencing, participating in cell division, and regulating immune response and other important biological processes. With the development of molecular biology, genetics, bioinformatics, and next-generation sequencing (NGS) technology, ncRNAs such as microRNA (miRNA), circular RNA (circRNA), long non-coding RNA (lncRNA), and P-element induced wimpy testis (PIWI)-interacting RNA (piRNA) are increasingly been shown to have potential in the practice of forensic medicine. NcRNAs, mainly miRNA, may provide new strategies and methods for the identification of tissues and body fluids, cause-of-death analysis, time-related estimation, age estimation, and the identification of monozygotic twins. In this review, we describe the research progress and application status of ncRNAs, mainly miRNA, and other ncRNAs such as circRNA, lncRNA, and piRNA, in forensic practice, including the identification of tissues and body fluids, cause-of-death analysis, time-related estimation, age estimation, and the identification of monozygotic twins. The close links between ncRNAs and forensic medicine are presented, and their research values and application prospects in forensic medicine are also discussed.

Forensic significance of intracardiac expressions of Nrf2 in acute myocardial ischemia

When exposed to oxidative and electrophilic stress, a protective antioxidant response is initiated by nuclear factor erythroid 2-related factor 2 (Nrf2). However, the extent of its importance in the forensic diagnosis of acute ischemic heart diseases (AIHD), such as myocardial infarction (MI), remains uncertain. On the other hand, immunohistochemical analyses of fibronectin (FN) and the terminal complement complex (C5b-9) prove valuable in identifying myocardial ischemia that precedes necrosis during the postmortem diagnosis of sudden cardiac death (SCD). In this study, we investigated the immunohistochemical levels of Nrf2, FN, and C5b-9 in human cardiac samples to explore their forensic relevance for the identification of acute cardiac ischemia. Heart samples were obtained from 25 AIHD cases and 39 non-AIHD cases as controls. Nrf2 was localized in the nuclei of cardiomyocytes, while FN and C5b-9 were detected in the myocardial cytoplasm. The number of intranuclear Nrf2 positive signals in cardiomyocytes increased in AIHD cases compared to control cases. Additionally, the grading of positive portions of cardiac FN and C5b-9 in the myocardium was also significantly enhanced in AIHD, compared to controls. Collectively, these results indicate that the immunohistochemical investigation of Nrf2 combined with FN, and/or C5b-9 holds the potential for identifying early-stage myocardial ischemic lesions in cases of SCD.

MicroRNA-1 Deficiency Is a Primary Etiological Factor Disrupting Cardiac Contractility and Electrophysiological Homeostasis

BACKGROUND

MicroRNA-1 (miR1), encoded by the genes miR1-1 and miR1-2, is the most abundant microRNA in the heart and plays a critical role in heart development and physiology. Dysregulation of miR1 has been associated with various heart diseases, where a significant reduction (>75%) in miR1 expression has been observed in patient hearts with atrial fibrillation or acute myocardial infarction. However, it remains uncertain whether miR1-deficiency acts as a primary etiological factor of cardiac remodeling.

METHODS

miR1-1 or miR1-2 knockout mice were crossbred to produce 75%-miR1-knockdown (75%KD; miR1-1+/-:miR1-2-/- or miR1-1-/-:miR1-2+/-) mice. Cardiac pathology of 75%KD cardiomyocytes/hearts was investigated by ECG, patch clamping, optical mapping, transcriptomic, and proteomic assays.

RESULTS

In adult 75%KD hearts, the overall miR1 expression was reduced to ≈25% of the normal wild-type level. These adult 75%KD hearts displayed decreased ejection fraction and fractional shortening, prolonged QRS and QT intervals, and high susceptibility to arrhythmias. Adult 75%KD cardiomyocytes exhibited prolonged action potentials with impaired repolarization and excitation-contraction coupling. Comparatively, 75%KD cardiomyocytes showcased reduced Na+ current and transient outward potassium current, coupled with elevated L-type Ca2+ current, as opposed to wild-type cells. RNA sequencing and proteomics assays indicated negative regulation of cardiac muscle contraction and ion channel activities, along with a positive enrichment of smooth muscle contraction genes in 75%KD cardiomyocytes/hearts. miR1 deficiency led to dysregulation of a wide gene network, with miR1's RNA interference-direct targets influencing many indirectly regulated genes. Furthermore, after 6 weeks of bi-weekly intravenous tail-vein injection of miR1 mimics, the ejection fraction and fractional shortening of 75%KD hearts showed significant improvement but remained susceptible to arrhythmias.

CONCLUSIONS

miR1 deficiency acts as a primary etiological factor in inducing cardiac remodeling via disrupting heart regulatory homeostasis. Achieving stable and appropriate microRNA expression levels in the heart is critical for effective microRNA-based therapy in cardiovascular diseases.

Influence of microRNAs on iNOS expression in postmortem human infarction hearts

MicroRNAs (miRNAs) are important post-transcriptional regulators in several diseases, including cancer, immunologic and cardiovascular diseases. A growing list of miRNAs are dysregulated in cardiac arrhythmias, contractility diseases, myocardial infarction (MI), sudden cardiac death (SCD), chronic heart failure and hypertrophy. However, the exact regulatory pathways, through which miRNAs exert their effects are often unclear. In this study, we measured the expression patterns of miR-21, miR-939 and miR-30e in postmortem human MI. The aim of the study was to examine the influence of these miRNAs on cardiac inducible nitric oxide synthase (iNOS) mRNA levels. We measured iNOS mRNA and miRNA expression patterns by means of qPCR. Further we used correlation analyses to determine causality between miRNA expression and cardiac iNOS levels. iNOS mRNA, miR-21, miR-939 and miR-30e were significantly upregulated in infarcted and non-infarcted regions of postmortem human MI hearts in comparison to healthy controls. While miR-21 and miR-939 showed their strongest expression in infarcted regions, miR-30e peaked in the non-infarcted myocardium. Further, we found a significant correlation between miR-939 and iNOS expression levels in controls and infarcted regions. The results indicate, that miR-939 is a regulator of cardiac iNOS expression. However, a massive iNOS activation might exceed the capability of miR-939 to keep its expression in balance. miR-21 and miR-30e do not seem to influence cardiac iNOS levels in MI. Further studies are needed to evaluate downstream targets of these miRNAs and their signaling pathways to clarify their role in human MI.

From multi-omics approaches to personalized medicine in myocardial infarction

Myocardial infarction (MI) is a prevalent cardiovascular disease characterized by myocardial necrosis resulting from coronary artery ischemia and hypoxia, which can lead to severe complications such as arrhythmia, cardiac rupture, heart failure, and sudden death. Despite being a research hotspot, the etiological mechanism of MI remains unclear. The emergence and widespread use of omics technologies, including genomics, transcriptomics, proteomics, metabolomics, and other omics, have provided new opportunities for exploring the molecular mechanism of MI and identifying a large number of disease biomarkers. However, a single-omics approach has limitations in understanding the complex biological pathways of diseases. The multi-omics approach can reveal the interaction network among molecules at various levels and overcome the limitations of the single-omics approaches. This review focuses on the omics studies of MI, including genomics, epigenomics, transcriptomics, proteomics, metabolomics, and other omics. The exploration extended into the domain of multi-omics integrative analysis, accompanied by a compilation of diverse online resources, databases, and tools conducive to these investigations. Additionally, we discussed the role and prospects of multi-omics approaches in personalized medicine, highlighting the potential for improving diagnosis, treatment, and prognosis of MI.

The Role of miRNA Expression Profile in Sudden Cardiac Death Cases

Sudden cardiac death (SCD) is one of the leading causes of death in the world and for this reason it has attracted the attention of numerous researchers in the field of legal medicine. It is not easy to determine the cause in a SCD case and the available methods used for diagnosis cannot always give an exhaustive answer. In addition, the molecular analysis of genes does not lead to a clear conclusion, but it could be interesting to focus attention on the expression level of miRNAs, a class of non-coding RNA of about 22 nucleotides. The role of miRNAs is to regulate the gene expression through complementary binding to 3'-untraslated regions of miRNAs, leading to the inhibition of translation or to mRNA degradation. In recent years, several studies were performed with the aim of exploring the use of these molecules as biomarkers for SCD cases, and to also distinguish the causes that lead to cardiac death. In this review, we summarize experiments, evidence, and results of different studies on the implication of miRNAs in SCD cases. We discuss the different biological starting materials with their respective advantages and disadvantages, studying miRNA expression on tissue (fresh-frozen tissue and FFPE tissue), circulating cell-free miRNAs in blood of patients affected by cardiac disease at high risk of SCD, and exosomal miRNAs analyzed from serum of people who died from SCD.

Estrogen-mediated mitigation of cardiac oxidative stress in ovariectomized rats is associated with upregulated cardiac circadian clock Per2 and heart-specific miRNAs

AIM

Estrogen (E2) confers cardioprotection in premenopausal women and in models of menopause and its effects, mostly studied in female reproductive organs, vary on a circadian rhythm basis in relation to the circadian clock genes. However, it remains unknown if a similar circadian pattern exists in the female heart in a manner that explains, at least partly, the cardioprotective effect of E2. The aim of the present investigation was to determine if upregulation of the circadian clock Per2 and its regulated heart-specific miRNAs, and redox enzymes contribute to the E2-mediated cardioprotection in ovariectomized rats.

MAIN METHODS

Rats were subjected to ovariectomy (OVX) 2-weeks prior to a 2-week E2 treatment. On the last treatment day, hearts were collected every 4 h. for ex-vivo biochemical measurements. In parallel studies, telemetric mean arterial pressure (MAP) was obtained at the tissue collection times.

KEY FINDINGS

OVX + E2 rats exhibited lower body weight during daytime and MAP during day and night times, and their hearts exhibited: (1) higher Per2 protein abundance, cardioprotective miRNAs (miRNA1, miRNA133a, miRNA208a, miRNA499), mALDH2, and catalase; (2) lower reactive oxygen species, cardio-detrimental miRNA652, carbonyl, MDA and HO-1 levels. The reciprocal Per2/HO-1 relationship was more evident during the daytime and correlated with the upregulated cardioprotective miRNAs in OVX + E2 rats. Finally, cardiac Per2, heart-specific miRNAs and reactive oxygen species levels and redox enzymes activities were similar in normal female and OVX + E2 rats.

SIGNIFICANCE

Enhancement of cardiac Per2, redox enzymes and heart-specific miRNAs likely contribute to E2-mediated mitigation of cardiac oxidative stress in OVX rats.

Investigating miRNA subfamilies: Can they assist in the early diagnosis of acute myocardial infarction?

This report focuses on small non-coding RNA molecules (miRNAs), which have emerged as potential biomarkers with variable diagnostic values and false-positives in different conditions that limit their clinical preference. Current investigations focus on small non-coding RNA molecules (miRNAs), which have emerged as potential biomarkers with variable diagnostic values and false-positives in different conditions that limit their clinical preference. We thoroughly scrutinize the leading pathology of myocardial infarction and contemporary alterations in miRNAs for their specificity, stability and significant prognostic value at the early stage of acute myocardial infarction (AMI). Based on secondary data analysis, we explore common biomarkers and further investigate included miRNA biomarkers for their specificity, stability and area under the curve (AUC) values. We conclude that a group of novel biomarkers, including miRNA-1, miRNA-208a/b and miRNA-499, could help predict the emergence of AMI at an early stage.

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.

Emerging Biomarkers of Acute Myocardial Infarction, An Overview of the Newest MicroRNAs

Globally, acute myocardial infarction (AMI) is the leading cause of death. Early and precise diagnosis is essential for medical care to enhance prognoses and reduce mortality. The diagnosis of AMI relies primarily on conventional circulating biomarkers. However, these markers have many drawbacks. Non-coding RNAs (ncRNAs) form a significant fraction of the transcriptome and have been shown to be essential for many biological processes, including the pathogenesis of the disease. ncRNAs can be utilized as biomarkers due to their important role in the disease's development. The current manuscript describes recent progress on the role of ncRNAs as new AMI biomarkers.

miRNA Dysregulation in Cardiovascular Diseases: Current Opinion and Future Perspectives

MicroRNAs (miRNAs), small noncoding RNAs, are post-transcriptional gene regulators that can promote the degradation or decay of coding mRNAs, regulating protein synthesis. Many experimental studies have contributed to clarifying the functions of several miRNAs involved in regulatory processes at the cardiac level, playing a pivotal role in cardiovascular disease (CVD). This review aims to provide an up-to-date overview, with a focus on the past 5 years, of experimental studies on human samples to present a clear background of the latest advances to summarize the current knowledge and future perspectives. SCOPUS and Web of Science were searched using the following keywords: (miRNA or microRNA) AND (cardiovascular diseases); AND (myocardial infarction); AND (heart damage); AND (heart failure), including studies published from 1 January 2018 to 31 December 2022. After an accurate evaluation, 59 articles were included in the present systematic review. While it is clear that miRNAs are powerful gene regulators, all the underlying mechanisms remain unclear. The need for up-to-date data always justifies the enormous amount of scientific work to increasingly highlight their pathways. Given the importance of CVDs, miRNAs could be important both as diagnostic and therapeutic (theranostic) tools. In this context, the discovery of “TheranoMIRNAs” could be decisive in the near future. The definition of well-setout studies is necessary to provide further evidence in this challenging field.

Suitable biomarkers for post-mortem differentiation of cardiac death causes: Quantitative analysis of miR-1, miR-133a and miR-26a in heart tissue and whole blood

Cardiovascular diseases are the most common causes of death worldwide. Cardiac death can occur as reaction to myocardial infarction (MI). A diagnostic challenge arises for sudden unexpected death (SUD) cases with structural abnormalities (SA) or without any structural abnormalities (without SA). Therefore, the identification of reliable biomarkers to differentiate cardiac cases from each other is necessary. In the current study, the potential of different microRNAs (miRNAs) as biomarkers in tissue and blood samples of cardiac death cases was analyzed. Blood and tissue samples of 24 MI, 21 SUD and 5 control (C) cases were collected during autopsy. Testing for significance and receiver operating characteristic analysis (ROC) were performed. The results show that miR-1, miR-133a and miR-26a possess a high diagnostic power to discriminate between different cardiac death causes in whole blood and in tissue.

Screening and evaluation of endogenous reference genes for miRNA expression analysis in forensic body fluid samples

MicroRNA (miRNA)-based methods for body fluid identification are promising tools in the practice of forensic science. The selection of appropriate endogenous reference genes as normalizers for the relative quantification of miRNA expression levels using quantitative reverse transcription-polymerase chain reaction (RTqPCR) is essential to avoid errors and improve the comparability of miRNA expression level data among different body fluids. In this study, small RNAs were isolated from individual donations of five forensically relevant body fluids (peripheral blood, menstrual blood, saliva, semen and vaginal secretions). Thirty-seven samples were subjected to high-throughput miRNA sequencing. By combining our results with those obtained through a literature investigation, 28 candidate RNAs were identified. Following RTqPCR validation, the candidate RNAs were preliminarily evaluated in 15 samples to exclude miRNAs with low expression and high variation. Then, the expression levels of 10 relatively stable candidate reference RNAs in 100 samples were determined and further analysed using four commonly employed programs (geNorm, NormFinder, BestKeeper and ΔCq). According to the comprehensive stability rankings of the four algorithms, miR-320a-3p was validated as the most stable endogenous reference gene among the five forensically relevant body fluids, followed by miR-484, SNORD43, miR-320c and RNU6b. Moreover, the combined application of miR-320a-3p with RNU6b could increase the normalization effect. In addition, a total of 56 mock samples placed outdoors and indoors for different times were prepared to further evaluate the stability of candidate reference RNAs, and miR-320a-3p remained the preferred reference gene. Furthermore, the relative expression levels of publicly accepted body fluid-specific miRNAs were determined in 30 samples to verify the practicality and effectiveness of the reference genes. Our results revealed a set of alternative reference genes and could promote the development and application of miRNA-based body fluid identification by determining optional reference genes for strict normalization.

Role of miR-143 and miR-146 in Risk Evaluation of Coronary Artery Diseases in Autopsied Samples

Coronary artery disease (CAD) is a common and fatal cardiovascular disease. Among known CAD risk factors, miRNA polymorphisms, such as Has-miR-143 (rs41291957 C>G) and Has-miR-146a (rs2910164 G>A), have emerged as important genetic markers of CAD. Despite many genetic association studies in multiple populations, no study assessing the association between CAD risk and SNPs of miR-143 and miR-146 was documented in the Japanese people. Therefore, using the TaqMan SNP assay, we investigated two SNP genotypes in 151 subjects with forensic autopsy-proven CAD. After pathological observation, we used ImageJ software to assess the degree of coronary artery atresia. Moreover, the genotypes and miRNA content of the two groups of samples with atresia <10% and >10% were analyzed. The results showed that the CC genotype of rs2910164 was more frequent in patients with CAD than in controls, which was associated with the risk of CAD in the study population. However, Has-miR-143 rs41291957 genotype did not show a clear correlation with the risk of CAD.

miR-208 inhibits myocardial tissues apoptosis in mice with acute myocardial infarction by targeting inhibition of PDCD4

This article aimed to investigate the role of miR-208 in the apoptosis of myocardial tissues in acute myocardial infarction (AMI) mice. The AMI mouse model was constructed. Then, miR-208 expression in AMI mice was regulated by transfection. The mouse myocardial tissues were subject to hematoxylin-eosin (HE) staining, TUNEL assay, and immunofluorescence analysis. H9c2 cell transfection and hypoxia induction were then completed, and cell apoptosis and cytokine levels were tested. Additionally, RNA pull-down and dual luciferase reporter gene assays were conducted for exploring the relation of miR-208 with programmed cell death 4 (PDCD4). Additionally, fluorescence in situ hybridization (FISH) was conducted for investigating miR-208 and PDCD4 colocalization within H9c2 cells. AMI mice had severe damage, apoptosis, decreased miR-208 expression, increased IL-1β, IL-6, IL-8 levels, whereas reduced IL-10 level within myocardial tissues. H9c2 cells under hypoxia induction exhibited decreased miR-208 expression, promoted apoptosis, increased protein expression of Bax and cleaved-caspase-3, decreased protein expression of Bcl-2 and caspase-3, elevated IL-1β, IL-6, IL-8 levels and decreased IL-10 level. miR-208 upregulation alleviated the damage and apoptosis of myocardial tissues in AMI mice. AMI mice with miR-208 upregulation showed decreased expression of Bax and cleaved-caspase-3, increased expression of Bcl-2 and caspase-3, reduced levels of IL-1β, IL-6, IL-8, whereas an increased level of IL-10. miR-208 showed direct inhibition of PDCD4. PDCD4 and miR-208 were mainly co-expressed in the cytoplasm. The upregulated PDCD4 expression abolished miR-208's suppression of H9c2 cell apoptosis induced by hypoxia. Besides this, miR-208 inhibited myocardial tissue apoptosis in AMI mice by inhibiting PDCD4 expression.

Clinical Application of Serum microRNAs in Atherosclerotic Coronary Artery Disease

MicroRNAs (miRs) are promising diagnostic, prognostic and therapeutic biomolecules for atherosclerotic cardiovascular disease. Atherosclerotic occlusive disease concerns a large population of patients, carrying the highest incidence of fatal and non-fatal adverse events, such as myocardial infarction, ischemic stroke, and limb ischemia, worldwide. Consistently, miRs are involved in regulation and pathogenesis of atherosclerotic coronary artery disease (CAD), acute coronary syndromes (ACS), both with ST-segment (STEMI) and non-ST segment elevation myocardial infarctions (NSTEMI), as well as cardiac remodeling and fibrosis following ACS. However, the genetic and molecular mechanisms underlying adverse outcomes in CAD are multifactorial, and sometimes difficult to interpret for clinicians. Therefore, in the present review paper we have focused on the clinical meaning and the interpretation of various miRs findings, and their potential application in routine clinical practice.

A systematic review of miRNAs as biomarkers for chemotherapy-induced cardiotoxicity in breast cancer patients reveals potentially clinically informative panels as well as key challenges in miRNA research

Breast cancer patients are at a particularly high risk of cardiotoxicity from chemotherapy having a detrimental effect on quality-of-life parameters and increasing the risk of mortality. Prognostic biomarkers would allow the management of therapies to mitigate the risks of cardiotoxicity in vulnerable patients and a key potential candidate for such biomarkers are microRNAs (miRNA). miRNAs are post-transcriptional regulators of gene expression which can also be released into the circulatory system and have been associated with the progression of many chronic diseases including many types of cancer. In this review, the evidence for the potential application of miRNAs as biomarkers for chemotherapy-induced cardiotoxicity (CIC) in breast cancer patientsis evaluated and a simple meta-analysis is performed to confirm the replication status of each reported miRNA. Further selection of miRNAs is performed by reviewing the reported associations of each miRNA with other cardiovascular conditions. Based on this research, the most representative panels targeting specific chemotherapy agents and treatment regimens are suggested, that contain several informative miRNAs, including both general markers of cardiac damage as well as those for the specific cancer treatments.

Bioengineering exosomes for treatment of organ ischemia-reperfusion injury

Ischemia-reperfusion (I/R) injury is a leading cause of death worldwide. It arises from blood reflowing after tissue hypoxia induced by ischemia that causes severe damages due to the accumulation of reactive oxygen species and the activation of inflammatory responses. Exosomes are the smallest members of the extracellular vesicles' family, which originate from nearly all eukaryotic cells. Exosomes have a great potential in the treatment of I/R injury either in native or modified forms. Native exosomes are secreted by different cell types, such as stem cells, and contain components such as specific miRNA molecules with tissue protective properties. On the other hand, exosome bioengineering has recently received increased attention in context of current advances in the purification, manipulation, biological characterization, and pharmacological applications. There are various pre-isolation and post-isolation manipulation approaches that can be utilized to increase the circulation half-life of exosomes or the availability of their bioactive cargos in the target site. In this review, the various therapeutic actions of native exosomes in different I/R injury will be discussed first. Exosome bioengineering approaches will then be explained, including pre- and post-isolation manipulation methods, applicability for delivery of bioactive agents to injured tissue, clinical translation issues, and future perspectives.

Human Heart Anoxia and Reperfusion Tissue (HEART) Model for the Rapid Study of Exosome Bound miRNA Expression As Biomarkers for Myocardial Infarction

Current biomarkers for myocardial infarction (MI) diagnosis are typically late markers released upon cell death, incapable of distinguishing between ischemic and reperfusion injury and can be symptoms of other pathologies. Circulating microRNAs (miRNAs) have recently been proposed as alternative biomarkers for MI diagnosis; however, detecting the changes in the human cardiac miRNA profile during MI is extremely difficult. Here, to study the changes in miRNA levels during acute MI, a heart-on-chip model with a cardiac channel, containing human induced pluripotent stem cell (hiPSC)-derived cardiomyocytes in human heart decellularized matrix and collagen, and a vascular channel, containing hiPSC-derived endothelial cells, is developed. This model is exposed to anoxia followed by normoxia to mimic ischemia and reperfusion, respectively. Using a highly sensitive miRNA biosensor that the authors developed, the exact same increase in miR-1, miR-208b, and miR-499 levels in the MI-on-chip and the time-matched human blood plasma samples collected before and after ischemia and reperfusion, is shown. That the surface marker profile of exosomes in the engineered model changes in response to ischemic and reperfusion injury, which can be used as biomarkers to detect MI, is also shown. Hence, the MI-on-chip model developed here can be used in biomarker discovery.

Differential Expression of microRNAs in acute and chronic heart Failure

BACKGROUND

MicroRNAs modify protein expression at a post-transcriptional level and their circulating levels may express the underlying molecular pathways.

OBJECTIVE

The purpose of this study was to assess the differential expression of microRNAs related to myocardial cell energy substrate, autophagy, and ischaemia in chronic and acute heart failure (HF).

METHODS

In this case-control study, we studied 19 patients with acute HF (AHF) and 19 patients with chronic HF (CHF). Basic demographic and clinical characteristics were collected from the patients upon arrival, at 48 hours, and at 120 hours. Blood samples for microRNAs measurements (miR-22, -92a, and -499), b type natriuretic peptide (BNP), C reactive protein, and high sensitivity cardiac troponin I were collected in all study points. In this study, we included subjects with a left ventricular ejection fraction of <40%.

RESULTS

At baseline circulating miR-22 levels were 1.9-fold higher (p<0.001), miR-92a levels were 1.25-fold higher (p=0.003), and miR-499 were 5-times lower (p<0.001) in AHF compared to CHF. Interestingly, circulating miR-499 was found to be associated with BNP levels (r=0.47, p=0.01). At follow-up there was a stepwise increase in the levels of all three examined microRNAs (miR-22, p=0.001, miR-92a, p=0.001, and miR-499, p<0.001) for AHF but not for CHF subjects.

CONCLUSIONS

MicroRNAs -22, -92a, and -499 are differentially expressed in chronic and acute HF subjects. MicroRNAs signatures are also differentially expressed up to the patients' discharge. These findings may have important implications in diagnosis, progression, and treatment in patients with chronic and acute heart failure.

Role of miRNA-1 and miRNA-21 in Acute Myocardial Ischemia-Reperfusion Injury and Their Potential as Therapeutic Strategy

Coronary artery disease remains the leading cause of death. Acute myocardial infarction (MI) is characterized by decreased blood flow to the coronary arteries, resulting in cardiomyocytes death. The most effective strategy for treating an MI is early and rapid myocardial reperfusion, but restoring blood flow to the ischemic myocardium can induce further damage, known as ischemia-reperfusion (IR) injury. Novel therapeutic strategies are critical to limit myocardial IR injury and improve patient outcomes following reperfusion intervention. miRNAs are small non-coding RNA molecules that have been implicated in attenuating IR injury pathology in pre-clinical rodent models. In this review, we discuss the role of miR-1 and miR-21 in regulating myocardial apoptosis in ischemia-reperfusion injury in the whole heart as well as in different cardiac cell types with special emphasis on cardiomyocytes, fibroblasts, and immune cells. We also examine therapeutic potential of miR-1 and miR-21 in preclinical studies. More research is necessary to understand the cell-specific molecular principles of miRNAs in cardioprotection and application to acute myocardial IR injury.

Heart-specific DNA methylation analysis in plasma for the investigation of myocardial damage

Background

Circulating cell-free DNA (cfDNA) can be released when myocardial damage occurs.

Methods

Here, we used the methylated CpG tandem amplification and sequencing (MCTA-seq) method for analyzing dynamic changes in heart-derived DNA in plasma samples from myocardial infarction (MI) patients.

Results

We identified six CGCGCGG loci showing heart-specific hypermethylation patterns. MCTA-seq deconvolution analysis combining these loci detected heart-released cfDNA in MI patients at hospital admission, and showed that the prominently elevated total cfDNA level after percutaneous coronary intervention (PCI) was derived from both the heart and white blood cells. Furthermore, for the top marker CORO6, we developed a digital droplet PCR (ddPCR) assay that clearly detected heart damage signals in cfDNA of MI patients at hospital admission.

Conclusions

Our study provides insights into MI pathologies and developed a new ddPCR assay for detecting myocardial damage in clinical applications.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-022-03234-9.

The Regulation Mechanisms and Clinical Application of MicroRNAs in Myocardial Infarction: A Review of the Recent 5 Years

Myocardial infarction (MI) is the most frequent end-point of cardiovascular pathology, leading to higher mortality worldwide. Due to the particularity of the heart tissue, patients who experience ischemic infarction of the heart, still suffered irreversible damage to the heart even if the vascular reflow by treatment, and severe ones can lead to heart failure or even death. In recent years, several studies have shown that microRNAs (miRNAs), playing a regulatory role in damaged hearts, bring light for patients to alleviate MI. In this review, we summarized the effect of miRNAs on MI with some mechanisms, such as apoptosis, autophagy, proliferation, inflammatory; the regulation of miRNAs on cardiac structural changes after MI, including angiogenesis, myocardial remodeling, fibrosis; the application of miRNAs in stem cell therapy and clinical diagnosis; other non-coding RNAs related to miRNAs in MI during the past 5 years.

The Role of miRNAs as New Molecular Biomarkers for Dating the Age of Wound Production: A Systematic Review

BACKGROUND

The timing of wounds production is a significant issue in forensic pathology. Although various methods have been evaluated, obtaining an accurate dating of lesions is still a challenge. The pathologist uses many parameters to value wound age, such as histological and immunohistochemical. In recent years, there have been many studies regarding the use of miRNAs in wound-age estimation; indeed, miRNAs have multiple potential uses in forensic pathology.

SCOPE

This review aims to verify the efficacy and feasibility of miRNAs as a tool for determining the timing of lesions.

MATERIALS AND METHODS

The authors conducted the systematic review according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. PubMed was used as a search engine to find articles published between January, 1st 2016 and October, 1st 2021, to evaluate the current state of the art regarding wound-age estimation.

RESULTS

A total of 256 articles were collected; after screening according to PRISMA guidelines, the systematic review included 8 articles. The studies included in this review were all Original articles evaluating the use of biomarkers for wound-age determination.

DISCUSSION AND CONCLUSION

The literature review showed that analysis of miRNA is an innovative field of study with significant potentiality in forensic pathology. There are few studies, and almost all of them are at an early stage. The challenge is to understand how to standardize the samples' selection to obtain reliable experimental data. This observation represents a necessary prerequisite to planning further clinical trials.

Diagnostic and Prognostic Value of miRNAs after Coronary Artery Bypass Grafting: A Review

MiRNAs are noncoding, 21-24 nucleotide-long RNA particles that control over 60% of genes. MiRNAs affect gene expression through binding to the 3'-untranslated region of messenger RNA (mRNA), thus inhibiting mRNA translation or inducing mRNA degradation. MiRNAs have been associated with various cardiovascular diseases, including heart failure, hypertension, left ventricular hypertrophy, or ischemic heart disease. In addition, miRNA expression alters during coronary artery bypass grafting (CABG) surgery, which could be used to predict perioperative outcomes. CABG is an operation in which complex coronary arteries stenosis is treated by bypassing atherosclerotic lesions with venous or arterial grafts. Despite a very low perioperative mortality rate and excellent long-term survival, CABG is associated with postoperative complications, including reperfusion injury, graft failure, atrial fibrillation and perioperative myocardial infarction. So far, no reliable diagnostic and prognostic tools to predict prognosis after CABG have been developed. Changes in the perioperative miRNA expression levels could improve the diagnosis of post-CABG myocardial infarction and atrial fibrillation and could be used to stratify risk after CABG. Herein, we describe the expression changes of different subtypes of miRNAs during CABG and review the diagnostic and prognostic utility of miRNAs in patients undergoing CABG.

Ferulic Acid Alleviates Oxidative Stress-Induced Cardiomyocyte Injury by the Regulation of miR-499-5p/p21 Signal Cascade

Objective

To investigate the protective effects and regulatory mechanisms of ferulic acid on oxidative stress-induced cardiomyocyte injury.

Methods

We established a cardiomyocyte oxidative stress cell model by H₂O₂ treatment and a mouse heart injury model by isoprenaline infusion of male C57BL/6 mice. Ferulic acid was applied to treat oxidative stress-induced cardiomyocyte injury. DHE staining was used to detect ROS production. DNA fragmentation, TUNEL assay, and cleaved caspase-3 were used to analyze cell apoptosis. Real-time PCR and Western blotting were used to analyze miRNA and protein levels to investigate the regulatory mechanisms of ferulic acid on oxidative stress-induced cardiomyocyte injury.

Results

Ferulic acid pretreatment significantly inhibited H₂O₂- and isoprenaline-induced oxidative stress and cell apoptosis by promoting miR-499-5p expression and inhibiting p21 expression. MiR-499-5p inhibition reversed the protective effects of ferulic acid. Further study found that ferulic acid could also attenuate isoprenaline-induced mouse heart fibrosis and cell apoptosis by reducing oxidative stress, inflammation, and apoptosis in vivo.

Conclusions

We proved that ferulic acid protects cardiomyocytes from oxidative stress-induced injury by regulating the miR-499-5p/p21signaling pathway, which provides insight into the clinical application of ferulic acid in the treatment of cardiovascular diseases.

MiRNAs as New Tools in Lesion Vitality Evaluation: A Systematic Review and Their Forensic Applications

Wound vitality demonstration is one of the most challenging fields in forensic pathology. In recent years, researchers focused on the application of histological and immunohistochemical staining in this sphere of study. It is based on the detection of inflammation, red cell infiltration, and tissue alterations at the histological examination, all of which are supposedly present in antemortem rather than post-mortem wounds. Nevertheless, some doubts about the reliability of those markers have arisen. Furthermore, the lack of a standardized protocol and the operator dependency of this approach make the proper interpretation of its results difficult. Moreover, a differential miRNAs expression has been demonstrated in antemortem and post-mortem wounds. Herein, a systematic review concerning the current knowledge about the use of miRNAs in lesion vitality evaluation is carried out, to encourage researchers to deepen this peculiar study area. A compendium about the potential miRNAs that may be further investigated as vitality markers is also provided. The aim is to collect all available data about this topic to direct further studies on this field and highlight the future applications of miRNAs in forensic pathology. We found 20 articles and a total of 51 miRNAs that are involved in inflammation and wound healing. Further studies are certainly needed to deepen the role of miRNAs in inflammatory processes in lesioned skin and to evaluate their reliability in distinguishing between antemortem and post-mortem lesions.

A Review on the Evolving Roles of MiRNA-Based Technologies in Diagnosing and Treating Heart Failure

MiRNA-regulated processes are pivotal in cardiovascular homeostasis and disease. These short non-coding RNAs have ideal properties that could be utilized as potential biomarkers; moreover, their functions as post-transcriptional regulators of mRNA make them interesting therapeutic targets. In this review, we summarize the current state of miRNA-based biomarkers in a variety of diseases leading to heart failure, as well as provide an outlook on developing miRNA-based therapies in the heart failure field.

miR-124 promotes apoptosis and inhibits the proliferation of vessel endothelial cells through P38/MAPK and PI3K/AKT pathways, making it a potential mechanism of vessel endothelial injury in acute myocardial infarction

Due to its rapid onset and high rates of fatality, acute myocardial infarction (AMI) has long been one of the most fatal diseases among all types of heart diseases. Therefore, intensive research efforts have been focused on understanding AMI's potential pathogenesis to seek effective treatment options. In the present study, 20 peripheral blood samples were collected from patients with AMI, after which reverse transcription-quantitative PCR analysis revealed that microRNA (miR)-124 levels in the peripheral blood of patients with AMI was significantly elevated compared with that in the control group. In vitro, a model using pcDNA3.1-miR-124 transfected human umbilical vein endothelial cells (HUVECs) indicated that overexpression of miR-124 could significantly promote the apoptosis and suppress the proliferation of HUVECs using flow cytometry, TUNEL assay and Cell Counting Kit-8 assays. Based on the present findings, RNA samples of HUVECs overexpressing miR-124 was extracted and sequenced to explore the gene expression profile after miR-124 overexpression. Gene Set Enrichment Analysis (GSEA) analysis revealed that the downregulated genes were mainly enriched in signaling pathways, such as PI3K-AKT, whilst the upregulated genes were mainly enriched in metabolism-related signaling pathways, such as the metabolism of xenobiotics by cytochrome P450 pathway. Additionally, Rideogram software was used to determine the chromosomal localization of the differentially expressed genes. The results demonstrated that they were distributed on all chromosomes except for chromosome Y. In addition, characteristic profiles of the differentially expressed genes caused by miR-124 overexpression were analyzed using Connectivity Map. In total, two medicines, anisomycin and sanguinarine, which function as p38/MAPK signaling agonists that can inhibit angiogenesis, presented with the highest enrichment scores. Together with the GSEA results, which indicated that the differentially expressed genes were mainly enriched in the angiogenesis-inhibiting PI3K/AKT signaling pathway, the present study reported that high expression of miR-124 was negatively associated with patients with AMI, promoting the apoptosis and suppressing the proliferation of vessel endothelial cells.

A multiplexed ion-exchange membrane-based miRNA (MIX·miR) detection platform for rapid diagnosis of myocardial infarction

Micro RNAs (miRNAs) have shown great potential as rapid and discriminating biomarkers for acute myocardial infarction (AMI) diagnosis. We have developed a multiplexed ion-exchange membrane-based miRNA (MIX·miR) preconcentration/sensing amplification-free platform for quantifying in parallel a panel of miRNAs, including miR-1, miR-208b, and miR-499, from the same plasma samples from: 1) reference subjects with no evident coronary artery disease (NCAD); 2) subjects with stable coronary artery disease (CAD); and 3) subjects experiencing ST-elevation myocardial infarction (STEMI) prior to (STEMI-pre) and following (STEMI-PCI) percutaneous coronary intervention. The picomolar limit of detection from raw plasma and 3-decade dynamic range of MIX·miR permits detection of the miRNA panel in untreated samples from disease patients and its precise standard curve, provided by large 0.1 to 1 V signals and eliminates individual sensor calibration. The use of molecular concentration feature reduces the assay time to less than 30 minutes and increases the detection sensitivity by bringing all targets close to the sensors. miR-1 was low for NCAD patients but more than one order of magnitude above the normal value for all samples from three categories (CAD, STEMI-pre, and STEMI-PCI) of patients with CAD. In fact, miR-1 expression levels of stable CAD, STEMI-pre and STEMI-PCI are each more than 10-fold higher than the previous class, in that order, well above the 95% confidence level of MIX·miR. Its overexpression estimate is significantly higher than the PCR benchmark. This suggests that, in contrast to protein biomarkers of myocardial injury, miR-1 appears to differentiate ischemia from both reperfusion injury and non-AMI CAD patients. The battery-operated MIX·miR can be a portable and low-cost AMI diagnostic device, particularly useful in settings where cardiac catheterization is not readily available to determine the status of coronary reperfusion.

Current Knowledge of MicroRNAs (miRNAs) in Acute Coronary Syndrome (ACS): ST-Elevation Myocardial Infarction (STEMI)

Regardless of the newly diagnostic and therapeutic advances, coronary artery disease (CAD) and more explicitly, ST-elevation myocardial infarction (STEMI), remains one of the leading causes of morbidity and mortality worldwide. Thus, early and prompt diagnosis of cardiac dysfunction is pivotal in STEMI patients for a better prognosis and outcome. In recent years, microRNAs (miRNAs) gained attention as potential biomarkers in myocardial infarction (MI) and acute coronary syndromes (ACS), as they have key roles in heart development, various cardiac processes, and act as indicators of cardiac damage. In this review, we describe the current available knowledge about cardiac miRNAs and their functions, and focus mainly on their potential use as novel circulating diagnostic and prognostic biomarkers in STEMI.

MiR-124 Regulates the Inflammation and Apoptosis in Myocardial Infarction Rats by Targeting STAT3

This study aimed to discover the effect of miR-124/STAT3 axis on the inflammation and cell apoptosis in myocardial infarction (MI) rats. Sprague-Dawley (SD) male rats were selected for establishing MI models and divided into Sham, MI, MI + anti-miR-124 and MI + Ad-miR-124 groups. Cardiac function was detected via echocardiography. Hematoxylin & eosin (HE) and triphenyltetrazolium chloride (TTC) staining were used to observe the pathological changes and infarction area, while transferase (TdT)-mediated D-UTP-biotin nick end labeling (TUNEL) assay was to observe myocardial apoptosis. Enzyme-linked immunosorbent assay (ELISA) was used to determine the serum levels of inflammatory cytokines. Quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) and western blotting were performed to determine the mRNA and protein levels, respectively. Dual luciferase reporter gene assay revealed that STAT3 was a target gene of miR-124. The expression levels of miR-124 were increased and the pSTAT3/STAT3 ratio was reduced in the MI rats. The rats in the MI group showed enhanced LVEDD and LVESD, reduced LVEF and LVFS, as well as larger myocardial infarction area compared with the Sham group, Besides, IL-1β, IL-6, TNF-α and MCP-1 levels were elevated and the expressions of Bax/Bcl-2 ratio and cleaved caspase-3 were downregulated in MI group. We further found that silencing miR-124 improved cardiac function, reduced infarction area and the levels of inflammatory cytokines, as well as prevented myocardial apoptosis in MI rats. Silencing miR-124 could inhibit the inflammation and apoptosis of myocardial cells, thereby relieving the MI injury via upregulation of STAT3.

miR-6718-5p and miR-4329 can be used as potential biomarkers for acute myocardial infarction

BACKGROUND

The prevention and prognosis of the onset or recurrence of acute myocardial infarction (AMI) is a difficult problem in contemporary research.

METHODS

In this study, peripheral blood samples were collected from seven patients with AMI and nine healthy adults, and exosome microRNAs (miRNAs) were extracted. The miRNA differential expression profiles of serum exosomes in patients with AMI were obtained by using the next-generation sequencing technology combined with bioinformatics analysis. Reverse-transcriptase polymerase chain reaction (RT-PCR) was used to verify the primary screening of differential exosome miRNAs to reveal the possible mechanism of their action on AMI.

RESULTS

Compared with healthy individuals, 544 miRNAs were upregulated and 518 miRNAs were downregulated in AMI patients preoperatively. Among these miRNAs, we selected miR-6718 and miR-4329 for qPCR verification. The expression of miR6718 and miR-4329 in patients with myocardial infarction was significantly lower than that in normal controls.

miR-3113-5p, miR-223-3p, miR-133a-3p, and miR-499a-5p are sensitive biomarkers to diagnose sudden cardiac death

Background

Sudden cardiac death (SCD) remains a great health threat and diagnostic challenge, especially those cases without positive autopsy findings. Molecular biomarkers have been urgently needed for the diagnosis of SCD displaying negative autopsy results. Due to their nature of stability, microRNAs (miRNAs) have emerged as promising diagnostic biomarkers for cardiovascular diseases.

Methods

This study investigated whether specific cardio-miRNAs (miR-3113-5p, miR-223-3p, miR-499a-5p, and miR-133a-3p) could serve as potential biomarkers for the diagnosis of SCD. Thirty-four SCD cases were selected, 18 categorized as SCD with negative autopsy (SCD-negative autopsy) findings and 16 as SCD with positive autopsy (SCD-positive autopsy) findings such as coronary atherosclerosis and gross myocardial scar. Carbon monoxide (CO) intoxication (n = 14) and fatal injury death (n = 14) that displayed no pathological changes of myocardium were selected as control group, respectively. Histological analyses were performed to reveal the pathological changes and real-time quantitative polymerase chain reaction (RT-qPCR) was used to determine the expression of those miRNAs.

Results

It showed that heart samples from the SCD-negative autopsy group displayed no remarkable difference with regard to the expression of cleaved-caspase3, CD31, and CD68 and the extent of fibrotic tissue accumulation when compared with control samples. The four cardio-miRNAs were significantly up-regulated in the SCD samples as compared with control. When discriminating SCD from controls, receiver operating characteristic (ROC) curve analysis revealed that the areas under the curve (AUC) of these 4 miRNAs were from 0.7839 to 0.9043 with sensitivity of 64.71–97.06% and specificity of 70–100%. Moreover, when discriminating the specific causes of SCD, the four miRNA expressions increased in the heart from the SCD-negative autopsy group as relative to that from the SCD-positive autopsy group, and a combination of two miRNAs presented higher diagnostic value (AUC = 0.7407–0.8667).

Conclusion

miR-3113-5p, miR-223-3p, miR-499a-5p, and miR-133a-3p may serve as independent diagnostic biomarkers for SCD, and a combination of two of these miRNAs could further discriminate detailed causes of SCD.

Insights into how environment shapes post-mortem RNA transcription in mouse brain

Most biological features that occur on the body after death were already deciphered by traditional medicine. However, the molecular mechanisms triggered in the cellular microenvironment are not fully comprehended yet. Previous studies reported gene expression alterations in the post-mortem condition, but little is known about how the environment could influence RNA degradation and transcriptional regulation. In this work, we analysed the transcriptome of mouse brain after death under three concealment simulations (air exposed, buried, and submerged). Our analyses identified 2,103 genes differentially expressed in all tested groups 48 h after death. Moreover, we identified 111 commonly upregulated and 497 commonly downregulated genes in mice from the concealment simulations. The gene functions shared by the individuals from the tested environments were associated with RNA homeostasis, inflammation, developmental processes, cell communication, cell proliferation, and lipid metabolism. Regarding the altered biological processes, we identified that the macroautophagy process was enriched in the upregulated genes and lipid metabolism was enriched in the downregulated genes. On the other hand, we also described a list of biomarkers associated with the submerged and buried groups, indicating that these environments can influence the post-mortem RNA abundance in its particular way.

Role of induced pluripotent stem cells in diagnostic cardiology

Ethical concerns about stem cell-based research have delayed important advances in many areas of medicine, including cardiology. The introduction of induced pluripotent stem cells (iPSCs) has supplanted the need to use human stem cells for most purposes, thus eliminating all ethical controversies. Since then, many new avenues have been opened in cardiology research, not only in approaches to tissue replacement but also in the design and testing of antiarrhythmic drugs. This methodology has advanced to the point where induced human cardiomyocyte cell lines can now also be obtained from commercial sources or tissue banks. Initial studies with readily available iPSCs have generally confirmed that their behavioral characteristics accurately predict the behavior of beating cardiomyocytes in vivo. As a result, iPSCs can provide new ways to study arrhythmias and heart disease in general, accelerating the development of new, more effective antiarrhythmic drugs, clinical diagnoses, and personalized medical care. The focus on producing cardiomyocytes that can be used to replace damaged heart tissue has somewhat diverted interest in a host of other applications. This manuscript is intended to provide non-specialists with a brief introduction and overview of the research carried out in the field of heart rhythm disorders.

MicroRNA-1: Diverse role of a small player in multiple cancers

The process of cancer initiation and development is a dynamic and complex mechanism involving multiple genetic and non-genetic variations. With the development of high throughput techniques like next-generation sequencing, the field of cancer biology extended beyond the protein-coding genes. It brought the functional role of noncoding RNAs into cancer-associated pathways. MicroRNAs (miRNAs) are one such class of noncoding RNAs regulating different cancer development aspects, including progression and metastasis. MicroRNA-1 (miR-1) is a highly conserved miRNA with a functional role in developing skeletal muscle precursor cells and cardiomyocytes and acts as a consistent tumor suppressor gene. In humans, two discrete genes, MIR-1-1 located on 20q13.333 and MIR-1-2 located on 18q11.2 loci encode for a single mature miR-1. Downregulation of miR-1 has been demonstrated in multiple cancers, including lung, breast, liver, prostate, colorectal, pancreatic, medulloblastoma, and gastric cancer. A vast number of studies have shown that miR-1 affects the hallmarks of cancer like proliferation, invasion and metastasis, apoptosis, angiogenesis, chemosensitization, and immune modulation. The potential therapeutic applications of miR-1 in multiple cancer pathways provide a novel platform for developing anticancer therapies. This review focuses on the different antitumorigenic and therapeutic aspects of miR-1, including how it regulates tumor development and associated immunomodulatory functions.

Forensic Application of Monoclonal Anti-Human Glycophorin A Antibody in Samples from Decomposed Bodies to Establish Vitality of the Injuries. A Preliminary Experimental Study

Glycophorins are an important group of red blood cell (RBC) transmembrane proteins. Monoclonal antibodies against GPA are employed in immunohistochemical staining during post-mortem examination: Through this method, it is possible to point out the RBC presence in tissues. This experimental study aims to investigate anti-GPA immunohistochemical staining in order to evaluate the vitality of the lesion from corpses in different decomposition state. Six cases were selected, analyzing autopsies’ documentation performed by the Institute of Legal Medicine of Rome in 2010–2018: four samples of fractured bones and three samples of soft tissues. For the control case, the fracture region of the femur was sampled. The results of the present study confirm the preliminary results of other studies, remarking the importance of the GPA immunohistochemical staining to highlight signs of survival. Moreover, this study suggests that the use of this technique should be routinely applied in cases of corpses with advanced putrefaction phenomena, even when the radiological investigation is performed, the macroscopic investigation is inconclusive, the H&E staining is not reliable. This experimental application demonstrated that the use of monoclonal antibody anti-human GPA on bone fractures and soft tissues could be important to verify whether the lesion is vital or not.

Circular RNAs in Sudden Cardiac Death Related Diseases: Novel Biomarker for Clinical and Forensic Diagnosis

The prevention and diagnosis of sudden cardiac death (SCD) are among the most important keystones and challenges in clinical and forensic practice. However, the diagnostic value of the current biomarkers remains unresolved issues. Therefore, novel diagnostic biomarkers are urgently required to identify patients with early-stage cardiovascular diseases (CVD), and to assist in the postmortem diagnosis of SCD cases without typical cardiac damage. An increasing number of studies show that circular RNAs (circRNAs) have stable expressions in myocardial tissue, and their time- and tissue-specific expression levels might reflect the pathophysiological status of the heart, which makes them potential CVD biomarkers. In this article, we briefly introduced the biogenesis and functional characteristics of circRNAs. Moreover, we described the roles of circRNAs in multiple SCD-related diseases, including coronary artery disease (CAD), myocardial ischemia or infarction, arrhythmia, cardiomyopathy, and myocarditis, and discussed the application prospects and challenges of circRNAs as a novel biomarker in the clinical and forensic diagnosis of SCD.

Diagnostic and Prognostic Biomarkers for Myocardial Infarction

The incidence of myocardial infarction (MI) increases every year worldwide. Better diagnostic and prognostic biomarkers for clinical applications are the consistent pursuit of MI research. In addition to electrocardiogram, echocardiography, coronary angiography, etc., circulating biomarkers are essential for the diagnosis, prognosis, and treatment effect monitoring of MI patients. In this review, we assessed both strength and weakness of MI circulating biomarkers including: (1) originated from damaged myocardial tissues including current golden standard cardiac troponin, (2) released from non-myocardial tissues due to MI-induced systems reactions, and (3) preexisted in blood circulation before the occurrence of MI event. We also summarized newly reported MI biomarkers. We proposed that the biomarkers preexisting in blood circulation before MI incidents should be emphasized in research and development for MI prevention in near future.

Difference in microRNA levels in the post-mortem blood from different sampling sites: A proof of concept

MicroRNAs have various characteristics, including stability, and tissue and disease specificity. One of the important issues in forensics is that biomarkers can differ quantitatively depending on the sampling site. We aimed at evaluating the differences in microRNA levels in the post-mortem (PM) blood from different sampling sites. The study subjects comprised seventeen males and eleven females. The number of cardiac deaths (CD) and non-cardiac deaths (NCD) was eleven and seventeen, respectively. A cardiopulmonary resuscitation (CPR) was performed in fifteen cases. Venous blood was obtained from the external iliac vein for peripheral blood (PB), inferior vena cava for pre-cardiac blood (CB), and coronary sinus for post-cardiac blood (coronary sinus blood, CSB). The selected target microRNAs were cardiac-specific (miR208 and miR-1) and non-cardiac microRNAs (miR-16 and let-7e). The levels of miR-208b and miR-1 in the PM blood differed according to its sampling site and showed an increasing order of tendency in the PB, CB, and CSB. However, these variations according to sampling sites did not correlate with the post-mortem interval and the levels did not differ between the CD and NCD groups, and between the CPR and non-CPR groups. MiR-16 and let-7e levels did not vary according to the sampling site. The present study confirms that the cardiac-specific microRNA levels in the PM blood from different sampling sites are different. In addition, this study showed that the characteristics of target microRNAs, such as tissue-specificity, should be considered and the sampling site for microRNAs should be presented in forensic applications.

MicroRNAs as Useful Tools to Estimate Time Since Death. A Systematic Review of Current Literature

Estimating the time of death remains the most challenging question in forensic medicine, because post-mortem interval (PMI) estimation can be a remarkably difficult goal to achieve. The aim of this review is to analyze the potential of microRNAs (miRNAs) to evaluate PMI. MiRNAs have been studied as hallmarks and biomarkers in several pathologies and have also showed interesting applications in forensic science, such as high sensible biomarkers in body fluid and tissue, for wound age determination and PMI evaluation due to their low molecular weight and tissue-specific expression. The present systematic review was carried out according to the Preferred Reporting Items for Systematic Review (PRISMA) standards. We performed an electronic search of PubMed, Science Direct Scopus, and Excerpta Medica Database (EMBASE) from the inception of these databases to 12 August 2020. The search terms were (“PMI miRNA” or “PMI micro RNA”) and (“miRNA” and “time of death”) in the title, abstract and keywords. Through analysis of scientific literature regarding forensic uses of miRNAs, has emerged that the intrinsic characteristics of such molecules, and their subsequent resistance to degradation, make them suitable as endogenous markers in order to determine PMI. However, further and larger studies with human samples and standardized protocols are still needed.

miR-1: A comprehensive review of its role in normal development and diverse disorders

MicroRNA-1 (miR-1) is a conserved miRNA with high expression in the muscle tissues. In humans, two discrete genes, MIRN1-1 and MIRN1-2 residing on a genomic region on 18q11.2 produce a single mature miRNA which has 21 nucleotides. miR-1 has a regulatory role on a number of genes including heat shock protein 60 (HSP60), Kruppel-like factor 4 (KLF4) and Heart And Neural Crest Derivatives Expressed 2 (HAND2). miR-1 has critical roles in the physiological processes in the smooth and skeletal muscles as well as other tissues, thus being involved in the pathogenesis of a wide range of disorders. Moreover, dysregulation of miR-1 has been noted in diverse types of cancers including gastric, colorectal, breast, prostate and lung cancer. In the current review, we provide the summary of the data regarding the role of this miRNA in the normal development and the pathogenic processes.

Metformin ameliorates cardiac conduction delay by regulating microRNA-1 in mice

Cardiac conduction delay may occur as a common complication of several cardiac diseases. A few therapies and drugs have a good effect on cardiac conduction delay. Metformin (Met) has a protective effect on the heart. This study's aim was to investigate whether Met could ameliorate cardiac conduction delay and its potential mechanism. Cardiac-specific microRNA-1 (miR-1) transgenic (TG) and myocardial infarction (MI) mouse models were used. Mice were administered with Met in an intragastric manner. We found that the expression of miR-1 was significantly up-regulated in H₂O₂ treated cardiomyocytes as well as in TG and MI mice. The protein levels of inwardly rectifying potassium channel 2.1 (Kir2.1) and Connexin43 (CX43) were down-regulated both in cardiomyocytes treated with H₂O₂ as well as cardiac tissues of TG and MI mice, as compared to their controls. Furthermore, the PR and QT intervals were prolonged, action potential duration (APD) was delayed, and conduction velocity (CV) was reduced, with upregulation of miR-1 in the hearts. In the meanwhile, intercalated disc injuries were found in the hearts of MI mice. Interestingly, Met can noticeably inhibit miR-1 upregulation and attenuate the changes mentioned above. Taken together, this suggested that Met could play an important role in improving cardiac conduction delay through inhibition of miR-1 expression. Our study proposes that Met is a potential candidate for the treatment of cardiac conduction delay and provides a new idea of treating arrhythmia with a drug.

Changes in gene expression patterns in postmortem human myocardial infarction

In murine models, the expression of inducible nitric oxide synthase (iNOS) in myocardial infarction (MI) has been reported to be the result of tissue injury and inflammation. In the present study, mRNA expression of iNOS, hypoxia-inducible factor-1α (HIF-1α), and vascular endothelial growth factor (VEGF) was investigated in postmortem human infarction hearts. Since HIF-1α is the inducible subunit of the transcription factor HIF-1, which regulates transcription of iNOS and VEGF, the interrelation between the three genes was observed, to examine the molecular processes during the emergence of MI. iNOS and VEGF mRNAs were found to be significantly upregulated in the affected regions of MI hearts in comparison to healthy controls. Upregulation of HIF-1α was also present but not significant. Correlation analysis of the three genes indicated a stronger and significant correlation between HIF-1α and iNOS mRNAs than between HIF-1α and VEGF. The results of the study revealed differences in the expression patterns of HIF-1 downstream targets. The stronger transcription of iNOS by HIF-1 in the affected regions of MI hearts may represent a pathological process, since no correlation of iNOS and HIF-1α mRNA was found in non-affected areas of MI hearts. Oxidative stress is considered to cause molecular changes in MI, leading to increased iNOS expression. Therefore, it may also represent a forensic marker for detection of early changes in heart tissue.

Disease severity-related alterations of cardiac microRNAs in experimental pulmonary hypertension

Right ventricular (RV) failure is the primary cause of death in pulmonary arterial hypertension (PAH). We hypothesized that heart‐relevant microRNAs, that is myomiRs (miR‐1, miR‐133a, miR‐208, miR‐499) and miR‐214, can have a role in the right ventricle in the development of PAH. To mimic PAH, male Wistar rats were injected with monocrotaline (MCT, 60 mg/kg, s.c.); control group received vehicle. MCT rats were divided into two groups, based on the clinical presentation: MCT group terminated 4 weeks after MCT administration and prematurely terminated group (ptMCT) displaying signs of terminal disease. Myocardial damage genes and candidate microRNAs expressions were determined by RT‐qPCR. Reduced blood oxygen saturation, breathing disturbances, RV enlargement as well as elevated levels of markers of myocardial damage confirmed PH in MCT animals and were more pronounced in ptMCT. MyomiRs (miR‐1/miR‐133a/miR‐208a/miR‐499) were decreased and the expression of miR‐214 was increased only in ptMCT group (P < 0.05). The myomiRs negatively correlated with Fulton index as a measure of RV hypertrophy in MCT group (P < 0.05), whereas miR‐214 showed a positive correlation (P < 0.05). We conclude that the expression of determined microRNAs mirrored the disease severity and targeting their pathways might represent potential future therapeutic approach in PAH.

MicroRNA Expression Profile Changes after Cardiopulmonary Bypass and Ischemia/Reperfusion-Injury in a Porcine Model of Cardioplegic Arrest

Identification of microRNAs (miRNA) associated with cardiopulmonary bypass, cardiac arrest and subsequent myocardial ischemia/reperfusion may unravel novel therapeutic targets and biomarkers. The primary aim of the present study was to investigate the effects of cardiopulmonary bypass and temperature of cardioplegic arrest on myocardial miRNA profile in pigs' left ventricular tissue. We employed next-generation sequencing to analyse miRNA profiles in the following groups: (1) hearts were arrested with antegrade warm St Thomas Hospital No. 2 (STH2) cardioplegia (n = 5; STH2-warm, 37 °C) and (2) cold STH2 (n = 6; STH2-cold, 4 °C) cardioplegia. Sixty min of ischemia was followed by 60 min of on-pump reperfusion with an additional 90 min of off-pump reperfusion. In addition, two groups without cardiac arrest (off-pump and on-pump group; n = 3, respectively) served as additional controls. STH2-warm and STH2-cold cardioplegia revealed no hemodynamic differences. In contrast, coronary venous creatine kinase-myocardial band (CK-MB) levels were significantly lower in pigs receiving STH2-warm cardioplegia (p < 0.05). Principal component analysis revealed that cardiopulmonary bypass and cardioplegic arrest markedly affected miRNAs in left ventricular tissue. Accordingly, ssc-miR-122, ssc-miR-10a-5p, ssc-miR-193a-3p, ssc-miR-499-3p, ssc-miR-374a-5p, ssc-miR-345-5p, ssc-miR-142-3p, ssc-miR-424-5p, ssc-miR-545-3p, ssc-miR-30b-5p, ssc-miR-145-5p, ssc-miR-374b-5p and ssc-miR-139-3p were differently regulated by cardiopulmonary bypass (false discovery rate (FDR) < 0.05 versus off-pump group). However, only ssc-miR-451 was differently expressed between STH2-warm and STH2-cold (FDR < 0.05). These data demonstrate for the first time that cardiopulmonary bypass and temperature of cardioplegic solution affected the expression of miRNAs in left ventricular tissue. In conclusion, specific miRNAs are potential therapeutic targets for limiting ischemia-reperfusion injury in patients undergoing cardiac surgery.

Identification of the miRNA-3185/CYP4A11 axis in cardiac tissue as a biomarker for mechanical asphyxia

Death by mechanical asphyxia is one of the most difficult conclusions to make in forensic science, especially in corpses displaying slight or no trauma to the surface of the body. Therefore, death by mechanical asphyxia is difficult to prove in medico-legal practice. MicroRNAs (miRNAs) are a class of small, non-coding RNAs involved in the regulation of numerous physiological and pathological cellular processes. In the present study, we demonstrate that significantly increased expression of miR-3185 in cardiac tissues was detected among cases of mechanical asphyxia compared to case of craniocerebral injury, hemorrhagic shock, sudden cardiac death and poisoning. We observed no correlation between the expression of miR-3185 and postmortem interval, age or temperature. Further work indicated that CYP4A11 is a putative target gene of miR-3185 and expressed at a relatively low level in cardiac tissue specimens from cases of mechanical asphyxia compared with specimens from cases of craniocerebral injury, hemorrhagic shock, sudden cardiac death and poisoning. Our results suggest that the miRNA-3185/CYP4A11 axis is associated with mechanical asphyxia-induced death and may provide new insight into asphyxial death investigations.