MicroRNAs in Peripheral Mononuclear Cells as Potential Biomarkers in Hypertensive Patients With Heart Failure With Preserved Ejection Fraction

Heart Failure with Preserved Ejection Fraction in the Elderly: Basic Mechanisms and Clinical Considerations

Heart failure (HF) with preserved ejection fraction (HFpEF) refers to a clinical condition in which the signs of HF, such as pulmonary congestion, peripheral edema and increased natriuretic-peptide levels, are present despite normal ejection-fractions and the absence of other causes (e.g. pericardial disease). The ejection-fraction cutoff for the definition of HFpEF has varied in the past, but recent society guidelines have settled on a consensus of 50%. HFpEF is particularly common in the elderly. The aim of this narrative review is to summarize the available literature regarding HFpEF in the elderly in terms of evidence for the age-dependence, specific clinical features and underlying mechanisms. In the clinical arena, we review the epidemiology, discuss distinct clinical phenotypes typically seen in the elderly, the importance of frailty, the role of biomarkers and the role of medical therapies (including sodium-glucose cotransport protein 2 (SGLT2)-inhibitors, renin-angiotensin-aldosterone system (RAAS) blockers, angiotensin-receptor/neprilysin inhibitors, diuretics and beta-adrenergic receptor blockers). We then go on to discuss the basic mechanisms implicated in HFpEF, including cellular senescence, fibrosis, inflammation, mitochondrial dysfunction, enhanced production of reactive-oxygen species, abnormal cellular calcium handling, changes in microRNA signaling, insulin resistance, and sex-hormone changes. Finally, we review knowledge gaps and promising areas of future investigation. Improved understanding of the specific clinical manifestations of HFpEF in the elderly and of the fundamental mechanisms contributing to the age-related risk of HFpEF promises to lead to novel diagnostic and treatment approaches that will improve outcomes for this common cardiac disorder in a vulnerable population.

Peripheral Blood MicroRNA-21 as a Predictive Biomarker for Heart Failure With Preserved Ejection Fraction in Old Hypertensives

BACKGROUND

Heart failure with preserved ejection fraction (HFpEF) is a major health issue with high morbidity and mortality. The epidemiology and the factors that cause HFpEF have not been fully clarified, while accurate predictive biomarkers are lacking. Our aim was to determine whether levels of microRNA-21 (miR-21) in peripheral blood monocytes, which play a critical role in many pathophysiological pathways of hypertensive heart disease, can predict the occurrence of HFpEF in older hypertensives, as well as the associated mortality and morbidity.

METHODS

We enrolled 151 elderly patients >60 years old with essential hypertension but without HF at baseline. miRs expression levels in peripheral blood mononuclear cells had been quantified by real-time reverse transcription polymerase chain reaction.

RESULTS

During a median follow-up of 8.2 years, 56 patients (37%) had an event. Levels of miR-21 in peripheral mononuclear blood cells proved to be significantly associated with the occurrence of HFpEF. More specifically, the median HFpEF-free period was 110 months for those with miR-21 >2.1 and 114 months for those with miR-21 <2.1. In addition, multivariate analysis showed that miR-21 (hazard ratio 11.14), followed by hemoglobin (Hg) (hazard ratio 0.56 for Hg >13.6 g/dl, a 45% risk reduction), were independent and the most significant predictors of HFpEF events.

CONCLUSIONS

miR-21 levels in peripheral blood monocytes are associated with the development of future HFpEF. Our findings may alter the risk models of HFpEF and support the rationale for further research into the modulation of miRs as biomarkers and treatment targets for HFpEF.

Non-coding RNAs in the pathophysiology of heart failure with preserved ejection fraction

Heart failure with preserved ejection fraction (HFpEF) is the largest unmet clinical need in cardiovascular medicine. Despite decades of research, the treatment option for HFpEF is still limited, indicating our ongoing incomplete understanding on the underlying molecular mechanisms. Non-coding RNAs, comprising of microRNAs (miRNAs), long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs), are non-protein coding RNA transcripts, which are implicated in various cardiovascular diseases. However, their role in the pathogenesis of HFpEF is unknown. Here, we discuss the role of miRNAs, lncRNAs and circRNAs that are involved in the pathophysiology of HFpEF, namely microvascular dysfunction, inflammation, diastolic dysfunction and cardiac fibrosis. We interrogated clinical evidence and dissected the molecular mechanisms of the ncRNAs by looking at the relevant in vivo and in vitro models that mimic the co-morbidities in patients with HFpEF. Finally, we discuss the potential of ncRNAs as biomarkers and potential novel therapeutic targets for future HFpEF treatment.

Literature Review: Pathophysiology of Heart Failure with Preserved Ejection Fraction

Heart failure with preserved ejection fraction is a growing public health concern, a disease with poor health outcomes, and is showing increased prevalence globally. This review paper explores the literature with a focus on the pathophysiology and microbiology of preserved ejection fraction heart failure while drawing connections between preserved and reduced ejection fraction states. The discussion teases out the cellular level changes that affect the overall dysfunction of the cardiac tissue, including the clinical manifestations, microbiological changes (endothelial cells, fibroblasts, cardiomyocytes, and excitation-contraction coupling), and the burden of structural diastolic dysfunction. The goal of this review is to summarize the pathophysiological disease state of heart failure with preserved ejection fraction to enhance understanding, knowledge, current treatment models of this pathology.

Diagnostic performance of microRNAs in the detection of heart failure with reduced or preserved ejection fraction: a systematic review and meta-analysis

AIM

Chronic heart failure (CHF) can be classified as heart failure with preserved ejection fraction (HFpEF) or with reduced ejection fraction (HFrEF). Currently, there is an unmet need for a minimally invasive diagnostic tool for different forms of CHF. We aimed to investigate the diagnostic potential of circulating microRNAs (miRNAs) for the detection of different CHF forms via a systematic review and meta-analysis approach.

METHODS AND RESULTS

Comprehensive search on Medline, Web of Science, Scopus, and EMBASE identified 45 relevant studies which were used for qualitative assessment. Out of these, 29 studies were used for qualitative and quantitative assessment and allowed to identify a miRNA panel able to detect HFrEF and HFpEF with areas under the curve (AUC) of 0.86 and 0.79, respectively. A panel of eight miRNAs (hsa-miR-18b-3p, hsa-miR-21-5p, hsa-miR-22-3p, hsa-miR-92b-3p, hsa-miR-129-5p, hsa-miR-320a-5p, hsa-miR-423-5p, and hsa-miR-675-5p) detected HFrEF cases with a sensitivity of 0.85, specificity of 0.88 and AUC of 0.91. A panel of seven miRNAs (hsa-miR-19b-3p, hsa-miR-30c-5p, hsa-miR-206, hsa-miR-221-3p, hsa-miR-328-5p, hsa-miR-375-3p, and hsa-miR-424-5p) identified HFpEF cases with a sensitivity of 0.82 and a specificity of 0.61.

CONCLUSIONS

Although conventional biomarkers (N-terminal pro-B-type natriuretic peptide and B-type natriuretic peptide) presented a better performance in detecting CHF patients, the results presented here pointed towards specific miRNA panels with potential additive values to circulating natriuretic peptides in the diagnosis of different classes of CHF. Equally important, miRNAs alone showed a reasonable capacity for 'ruling out' patients with HFrEF or HFpEF. Additional studies with large populations are required to confirm the diagnostic potential of miRNAs for sub-classes of CHF.

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.

MicroRNAs as the Potential Regulators of SARS-CoV-2 Infection and Modifiers of the COVID-19 Clinical Features

The pandemic of coronavirus disease 2019 (COVID-19) warrants the identification of factors that may determine both risk and severity of infection. The factors include microRNAs that have a wide regulatory potential and hence are particularly interesting. The review focuses on the potential roles of human microRNAs and the viral genome as well as microRNAs in SARS-CoV-2 infection and clinical features of COVID-19. The review summarizes the information about the human microRNAs that are thought to specifically bind to the SARS-CoV-2 genome and considers their expression levels in various organs (cells) in both healthy state and pathologies that are risk factors for severe COVID-19. Potential mechanisms whereby SARS-CoV-2 may affect the clinical features of COVID-19 are discussed in brief. The mechanisms include blocking of human microRNAs and RNA-binding proteins, changes in gene expression in infected cells, and possible epigenetic modifications of the human genome with the participation of coronavirus microRNAs.

Combined detection of miR-21-5p, miR-30a-3p, miR-30a-5p, miR-155-5p, miR-216a and miR-217 for screening of early heart failure diseases

The use of circulating microRNAs as biomarkers opens up new opportunities for the diagnosis of cardiovascular diseases because of their specific expression profiles. The aim of the present study was to identify circulating microRNAs in human plasma as potential biomarkers of heart failure and related diseases. We used real-time quantitative PCR to screen microRNA in plasma samples from 62 normal controls and 62 heart failure samples. We found that circulating miR-21-5p, miR-30a-3p, miR-30a-5p, miR-155-5p, miR-216a and miR-217 expressed differently between healthy controls and heart failure patients. Plasma levels of miR-21-5p, miR-30a-3p, miR-30a-5p, miR-155-5p, miR-216a and miR-217 were unaffected by hemolysis. Correlation analysis showed any two of these miRNAs possess a strong correlation, indicating a possibility of combined analysis. MiR-21-5p, miR-30a-3p, miR-30a-5p, miR-155-5p, miR-216a and miR-217 could be combined in two or three or more combinations. The results suggest that miR-21-5p, miR-30a-3p, miR-30a-5p, miR-155-5p, miR-216a and miR-217 may be a new diagnostic biomarker for heart failure and related diseases.

Aging, MicroRNAs, and Heart Failure

Aging is a major risk factor for heart failure, one of the leading causes of death in Western society. The mechanisms that underlie the different forms of heart failure have been elucidated only in part and the role of noncoding RNAs is still poorly characterized. Specifically, microRNAs (miRNAs), a class of small noncoding RNAs that can modulate gene expression at the posttranscriptional level in all cells, including myocardial and vascular cells, have been shown to play a role in heart failure with reduced ejection fraction. In contrast, miRNAs role in heart failure with preserved ejection fraction, the predominant form of heart failure in the elderly, is still unknown. In this review, we will focus on age-dependent miRNAs in heart failure and on some other conditions that are prevalent in the elderly and are frequently associated with heart failure with preserved ejection fraction.

Transcriptomic Research in Heart Failure with Preserved Ejection Fraction: Current State and Future Perspectives

Heart failure with preserved ejection fraction (HFpEF) is increasing in incidence and has a higher prevalence compared with heart failure with reduced ejection fraction. So far, no effective treatment of HFpEF is available, due to its complex underlying pathophysiology and clinical heterogeneity. This article aims to provide an overview and a future perspective of transcriptomic biomarker research in HFpEF. Detailed characterisation of the HFpEF phenotype and its underlying molecular pathomechanisms may open new perspectives regarding early diagnosis, improved prognostication, new therapeutic targets and tailored therapies accounting for patient heterogeneity, which may improve quality of life. A combination of cross-sectional and longitudinal study designs with sufficiently large sample sizes are required to support this concept.

Unlocking the Value of White Blood Cells for Heart Failure Diagnosis

Cardiovascular disease (CVD) is the single greatest cause of mortality and morbidity worldwide. Inciting 85% of CVD fatalities is heart failure, often resulting in or from a myocardial infarction. Early detection along with pharmacological treatment and lifestyle adaptation can result in better prognosis. Biomarkers are molecular or physiological measures that indicate disease presence, status, and severity. However, not all forms of heart failure are created equal. Current mainstay biomarkers for heart failure, including NT-pro-BNP and ejection fraction, lack sensitivity for many patients. Circulating white blood cells and peripheral blood mononuclear cells (PBMCs) are emerging as surrogate biopsies, reflecting molecular changes in the heart. We discuss the advantages of PBMCs over other sources, as well as limitations and considerations. We urge medical center biobanks to collect, isolate and store circulating white blood cells as a rich source of biomarkers to catalyze the discovery of novel diagnostic tools for heart failure.

Cardiac miRNA Expression and their mRNA Targets in a Rat Model of Prediabetes

Little is known about the mechanism of prediabetes-induced cardiac dysfunction. Therefore, we aimed to explore key molecular changes with transcriptomic and bioinformatics approaches in a prediabetes model showing heart failure with preserved ejection fraction phenotype. To induce prediabetes, Long-Evans rats were fed a high-fat diet for 21 weeks and treated with a single low-dose streptozotocin at week 4. Small RNA-sequencing, in silico microRNA (miRNA)-mRNA target prediction, Gene Ontology analysis, and target validation with qRT-PCR were performed in left ventricle samples. From the miRBase-annotated 752 mature miRNA sequences expression of 356 miRNAs was detectable. We identified two upregulated and three downregulated miRNAs in the prediabetic group. We predicted 445 mRNA targets of the five differentially expressed miRNAs and selected 11 mRNAs targeted by three differentially expressed miRNAs, out of which five mRNAs were selected for validation. Out of these five targets, downregulation of three mRNAs i.e., Juxtaposed with another zinc finger protein 1 (Jazf1); RAP2C, member of RAS oncogene family (Rap2c); and Zinc finger with KRAB and SCAN domains 1 (Zkscan1) were validated. This is the first demonstration that prediabetes alters cardiac miRNA expression profile. Predicted targets of differentially expressed miRNAs include Jazf1, Zkscan1, and Rap2c mRNAs. These transcriptomic changes may contribute to the diastolic dysfunction and may serve as drug targets.

Epigenetic Biomarkers in Cardiovascular Diseases

Cardiovascular diseases are the number one cause of death worldwide and greatly impact quality of life and medical costs. Enormous effort has been made in research to obtain new tools for efficient and quick diagnosis and predicting the prognosis of these diseases. Discoveries of epigenetic mechanisms have related several pathologies, including cardiovascular diseases, to epigenetic dysregulation. This has implications on disease progression and is the basis for new preventive strategies. Advances in methodology and big data analysis have identified novel mechanisms and targets involved in numerous diseases, allowing more individualized epigenetic maps for personalized diagnosis and treatment. This paves the way for what is called pharmacoepigenetics, which predicts the drug response and develops a tailored therapy based on differences in the epigenetic basis of each patient. Similarly, epigenetic biomarkers have emerged as a promising instrument for the consistent diagnosis and prognosis of cardiovascular diseases. Their good accessibility and feasible methods of detection make them suitable for use in clinical practice. However, multicenter studies with a large sample population are required to determine with certainty which epigenetic biomarkers are reliable for clinical routine. Therefore, this review focuses on current discoveries regarding epigenetic biomarkers and its controversy aiming to improve the diagnosis, prognosis, and therapy in cardiovascular patients.

Comparison of Cardiac miRNA Transcriptomes Induced by Diabetes and Rapamycin Treatment and Identification of a Rapamycin-Associated Cardiac MicroRNA Signature

Rapamycin (Rap), an inhibitor of mTORC1, reduces obesity and improves lifespan in mice. However, hyperglycemia and lipid disorders are adverse side effects in patients receiving Rap treatment. We previously reported that diabetes induces pansuppression of cardiac cytokines in Zucker obese rats (ZO-C). Rap treatment (750 μg/kg/day for 12 weeks) reduced their obesity and cardiac fibrosis significantly; however, it increased their hyperglycemia and did not improve their cardiac diastolic parameters. Moreover, Rap treatment of healthy Zucker lean rats (ZL-C) induced cardiac fibrosis. Rap-induced changes in ZL-C's cardiac cytokine profile shared similarities with that of diabetes-induced ZO-C. Therefore, we hypothesized that the cardiac microRNA transcriptome induced by diabetes and Rap treatment could share similarities. Here, we compared the cardiac miRNA transcriptome of ZL-C to ZO-C, Rap-treated ZL (ZL-Rap), and ZO (ZO-Rap). We report that 80% of diabetes-induced miRNA transcriptome (40 differentially expressed miRNAs by minimum 1.5-fold in ZO-C versus ZL-C; p ≤ 0.05) is similar to 47% of Rap-induced miRNA transcriptome in ZL (68 differentially expressed miRNAs by minimum 1.5-fold in ZL-Rap versus ZL-C; p ≤ 0.05). This remarkable similarity between diabetes-induced and Rap-induced cardiac microRNA transcriptome underscores the role of miRNAs in Rap-induced insulin resistance. We also show that Rap treatment altered the expression of the same 17 miRNAs in ZL and ZO hearts indicating that these 17 miRNAs comprise a unique Rap-induced cardiac miRNA signature. Interestingly, only four miRNAs were significantly differentially expressed between ZO-C and ZO-Rap, indicating that, unlike the nondiabetic heart, Rap did not substantially change the miRNA transcriptome in the diabetic heart. In silico analyses showed that (a) mRNA-miRNA interactions exist between differentially expressed cardiac cytokines and miRNAs, (b) human orthologs of rat miRNAs that are strongly correlated with cardiac fibrosis may modulate profibrotic TGF-β signaling, and (c) changes in miRNA transcriptome caused by diabetes or Rap treatment include cardioprotective miRNAs indicating a concurrent activation of an adaptive mechanism to protect the heart in conditions that exacerbate diabetes.

Combined Use of Circulating miR-133a and NT-proBNP Improves Heart Failure Diagnostic Accuracy in Elderly Patients

Background

Circulating microRNAs (miRNAs) are emerging as novel biomarkers for detecting cardiovascular diseases. Here, circulating miR-133a and miR-221 were investigated as potential diagnostic biomarkers for heart failure (HF) patients, particularly in elderly patients.

Material/Methods

A total of 94 elderly HF patients (mean age=77.4 years old) and 31 healthy controls (age- and sex-matched) participated in this study. Plasma NT-proBNP levels were measured using an electrochemiluminescence immunoassay, and circulating miR-133a and miR-221 levels were examined using real-time quantitative PCR, with diagnostic efficacies determined for each independently and in combination.

Results

MiR-133a expression increased by 4.6-fold (P<0.001) and miR-221 expression increased by 2.0-fold (P<0.001) in the elderly HF patients relative to the healthy controls. ROC curves were generated and AUC values of 0.863 for miR-133a (CI95%: 0.800–0.927), 0.718 for miR-221 (CI95%: 0.622–0.813), and 0.895 for NT-proBNP (CI95%: 0.841–0.948) were obtained. Unlike NT-proBNP, miR-133a and miR-221 were found to be unaffected by age, BMI, renal function, albumin, or Hb levels. More importantly, the diagnostic value of NT-proBNP was found to be improved when combined with any of the examined miRNA biomarkers alone or in a panel. When combining miR-133a with NT-proBNP, an AUC value of 0.975 (CI95%: 0.950–0.999) was obtained, which was significantly higher than for NT-proBNP alone (z=2.395, P=0.016).

Conclusions

miR-133a and miR-221 can serve as potential HF diagnostic biomarkers in elderly patients. Moreover, the diagnostic accuracy of NT-proBNP can be improved by the addition of miR-133a.