Myocardial Fibrosis in Heart Failure: Anti-Fibrotic Therapies and the Role of Cardiovascular Magnetic Resonance in Drug Trials

Exploring in vivo and in vitro models for heart failure with biomarker insights: a review

BACKGROUND

Heart failure (HF) is a condition characterized by the heart's inability to meet the body's demands, resulting in various complications. Two primary types of HF exist, namely HF with preserved left ventricular ejection fraction (LVEF) and HF reduced with LVEF. The progression of HF involves compensatory mechanisms such as cardiac hypertrophy, fibrosis, and alterations in gene expression. Pressure overload and volume overload are common etiologies of HF, with pressure overload often stemming from conditions like hypertension, leading to left ventricular hypertrophy and fibrosis. In contrast, volume overload can arise from chronic valvular regurgitant disease, also inducing left ventricular hypertrophy.

MAIN BODY

In vitro cell culture techniques serve as vital tools in studying HF pathophysiology, allowing researchers to investigate cellular responses and potential therapeutic targets. Additionally, biomarkers, measurable biological characteristics, play a crucial role in diagnosing and predicting HF. Some notable biomarkers include adrenomedullin, B-type natriuretic peptide, copeptin, galectin-3, interleukin-6, matrix metalloproteinases (MMPs), midregional pro-atrial natriuretic peptide, myostatin, procollagen type I C-terminal propeptide, procollagen type III N-terminal propeptide and tissue inhibitors of metalloproteinases (TIMPs). These biomarkers aid in HF diagnosis, assessing its severity, and monitoring treatment response, contributing to a deeper understanding of the disease and potentially leading to improved management strategies and outcomes.

CONCLUSIONS

This review provides comprehensive insights into various in vivo models of HF, commonly utilized cell lines in HF research, and pivotal biomarkers with diagnostic relevance for HF. By synthesizing this information, researchers gain valuable resources to further explore HF pathogenesis, identify novel therapeutic targets, and enhance diagnostic and prognostic approaches.

Cardiac dysfunction in patients with cirrhosis and acute decompensation

The prevalence of cirrhotic cardiomyopathy (CCM) has been reported as high as 60%-70% in patients with liver cirrhosis and is associated with various negative outcomes. There has been a growing understanding of CCM over recent years. Indeed, the development of imaging techniques has enabled new diagnostic criteria to be proposed by the Cirrhotic Cardiomyopathy Consortium. However, important unanswered questions remain over pathophysiological mechanisms, optimal diagnostic modalities and potential treatment options. While there has been an increasing volume of literature evaluating CCM, there is a lack of clarity on its implications in acute decompensation, acute-on-chronic liver failure and following interventions such as transjugular intrahepatic portosystemic shunt insertion and liver transplantation. This review aims to summarise the literature in these challenging domains and suggest where future research should focus. We conclude that systemic inflammation and structural myocardial changes are likely to be crucial in the pathophysiology of the disease, but the relative contribution of different components remains elusive. Furthermore, future studies need to use standardised diagnostic criteria for CCM as well as incorporate newer imaging techniques assessing both myocardial structure and function. Finally, while specific treatments are currently lacking, therapeutics targeting systemic inflammation, microbial dysbiosis and bacterial translocation are promising targets and warrant further research.

Cardiac fibrosis as a predictor for sudden cardiac death after transcatheter aortic valve implantation

BACKGROUND

Cardiac fibrosis plays a major pathophysiological role in any form of chronic heart disease, and high levels are associated with poor outcome. Diffuse and focal cardiac fibrosis are different subtypes, which have different pathomechanisms and prognostic implications. The total fibrosis burden in endomyocardial biopsy tissue was recently proved to play an independent prognostic role in aortic stenosis patients after transcatheter aortic valve implantation (TAVI).

AIMS

Here, for the first time, we aim to assess the specific impact of different fibrosis subtypes on sudden cardiac death (SCD) as a primary reason for cardiovascular mortality after TAVI.

METHODS

The fibrosis pattern was assessed histologically in the left ventricular biopsies obtained during TAVI interventions in 161 patients, who received a structured follow-up thereafter.

RESULTS

Receiver operating characteristic analyses, performed 6, 12, 24 and 48 months after TAVI, showed diffuse, but not focal, fibrosis as a significant predictor for SCD at all timepoints, with the highest area under the curve at the first time point and a decrease in its SCD predictivity over time. In both multivariate Cox proportional hazards and Fine-Gray competing risk models, including both fibrosis subtypes, as well as age, sex and ejection fraction, high diffuse fibrosis remained statistically significant. Accordingly, it represents an independent SCD predictor, most importantly for the occurrence of early events.

CONCLUSIONS

The burden of diffuse cardiac fibrosis plays an important and independent prognostic role regarding SCD early after TAVI. Therefore, the histological evaluation of fibrosis topography has value as a prognostic tool for TAVI patients and may help to tailor individualised approaches to optimise their postinterventional management.

Fibroblast Diversity and Epigenetic Regulation in Cardiac Fibrosis

Cardiac fibrosis, a process characterized by excessive extracellular matrix (ECM) deposition, is a common pathological consequence of many cardiovascular diseases (CVDs) normally resulting in organ failure and death. Cardiac fibroblasts (CFs) play an essential role in deleterious cardiac remodeling and dysfunction. In response to injury, quiescent CFs become activated and adopt a collagen-secreting phenotype highly contributing to cardiac fibrosis. In recent years, studies have been focused on the exploration of molecular and cellular mechanisms implicated in the activation process of CFs, which allow the development of novel therapeutic approaches for the treatment of cardiac fibrosis. Transcriptomic analyses using single-cell RNA sequencing (RNA-seq) have helped to elucidate the high cellular diversity and complex intercellular communication networks that CFs establish in the mammalian heart. Furthermore, a significant body of work supports the critical role of epigenetic regulation on the expression of genes involved in the pathogenesis of cardiac fibrosis. The study of epigenetic mechanisms, including DNA methylation, histone modification, and chromatin remodeling, has provided more insights into CF activation and fibrotic processes. Targeting epigenetic regulators, especially DNA methyltransferases (DNMT), histone acetylases (HAT), or histone deacetylases (HDAC), has emerged as a promising approach for the development of novel anti-fibrotic therapies. This review focuses on recent transcriptomic advances regarding CF diversity and molecular and epigenetic mechanisms that modulate the activation process of CFs and their possible clinical applications for the treatment of cardiac fibrosis.

Association of Lipoprotein(a) Levels With Myocardial Fibrosis in the Multi-Ethnic Study of Atherosclerosis

BACKGROUND

Lipoprotein(a) (Lp[a]) has been identified as an emerging risk factor for adverse cardiovascular (CV) outcomes, including heart failure. However, the connections among Lp(a), myocardial fibrosis (interstitial and replacement), and cardiac remodeling as pathways to CV diseases remains unclear.

OBJECTIVES

This study investigated the relationship between Lp(a) levels and myocardial fibrosis by cardiac magnetic resonance (CMR) T1 mapping and late gadolinium enhancement, as well as cardiac remodeling by cine CMR, in the MESA (Multi-Ethnic Study of Atherosclerosis) cohort.

METHODS

The study included 2,040 participants with baseline Lp(a) measurements and T1 mapping for interstitial myocardial fibrosis (IMF) evaluation in 2010. Lp(a) was analyzed as a continuous variable (per log unit) and using clinical cutoff values of 30 and 50 mg/dL. Multivariate linear and logistic regression were used to assess the associations of Lp(a) with CMR measures of extracellular volume (ECV fraction [ECV%]), native T1 time, and myocardial scar, as well as parameters of cardiac remodeling, in 2,826 participants.

RESULTS

Higher Lp(a) levels were associated with increased ECV% (per log-unit Lp[a]; β = 0.2%; P = 0.007) and native T1 time (per log-unit Lp[a]; β = 4%; P < 0.001). Similar relationships were observed between elevated Lp(a) levels and a higher risk of clinically significant IMF defined by prognostic thresholds per log-unit Lp(a) of ECV% (OR: 1.20; 95% CI: 1.04-1.43) and native T1 (OR: 1.2; 95% CI: 1.1-1.4) equal to 30% and 955 ms, respectively. Clinically used Lp(a) cutoffs (30 and 50 mg/dL) were associated with greater prevalence of myocardial scar (OR: 1.85; 95% CI: 1.1-3.2 and OR: 1.9; 95% CI: 1.1-3.4, respectively). Finally, higher Lp(a) levels were associated with left atrial enlargement and dysfunction.

CONCLUSIONS

Elevated Lp(a) levels are linked to greater subclinical IMF, increased myocardial scar prevalence, and left atrial remodeling.

Unveiling post-MIS-N cardiomyopathy by longitudinal multimodality global cardiac assessment from neonatal insult to 16-month follow-up

A full-term male neonate presented on the 11th day of life with late-onset multisystem inflammatory syndrome-neonate (MIS-N) (cardioneurological compromise). Immediate anti-inflammatory modulation led to a gradual recovery of neurological and coronary lesions. However, temporal evaluation unmasked silent myocardial dysfunction in echocardiography validated further by elevated biomarkers, myocardial fibrosis in cardiac magnetic resonance imaging, and abnormal strain study persisting till 16 months of follow-up. This revealed a hitherto unknown and rare progression of MIS-N into dilated cardiomyopathy.

The Role of Galectin-3 in Heart Failure-The Diagnostic, Prognostic and Therapeutic Potential-Where Do We Stand?

Heart failure (HF) is a clinical syndrome with high morbidity and mortality, and its prevalence is rapidly increasing. Galectin-3 (Gal-3) is an important factor in the pathophysiology of HF, mainly due to its role in cardiac fibrosis, inflammation, and ventricular remodeling. Fibrosis is a hallmark of cardiac remodeling, HF, and atrial fibrillation development. This review aims to explore the involvement of Gal-3 in HF and its role in the pathogenesis and clinical diagnostic and prognostic significance. We report data on Gal-3 structure and molecular mechanisms of biological function crucial for HF development. Over the last decade, numerous studies have shown an association between echocardiographic and CMR biomarkers in HF and Gal-3 serum concentration. We discuss facts and concerns about Gal-3's utility in acute and chronic HF with preserved and reduced ejection fraction for diagnosis, prognosis, and risk stratification. Finally, we present attempts to use Gal-3 as a therapeutic target in HF.

Myocardial fibrosis in rheumatic heart disease: emerging concepts and clinical implications

Rheumatic heart disease (RHD) remains a significant cardiovascular burden in the world even though it is no longer common in affluent countries. Centuries of history surrounding this disease provide us with a thorough understanding of its pathophysiology. Infections in the throat, skin, or mucosa are the gateway for Group A Streptococcus (GAS) to penetrate our immune system. A significant inflammatory response to the heart is caused by an immunologic cascade triggered by GAS antigen cross-reactivity. This exaggerated immune response is primarily responsible for cardiac dysfunction. Recurrent inflammatory processes damage all layers of the heart, including the endocardium, myocardium, and pericardium. A vicious immunological cycle involving inflammatory mediators, angiotensin II, and TGF-β promotes extracellular matrix remodeling, resulting in myocardial fibrosis. Myocardial fibrosis appears to be a prevalent occurrence in patients with RHD. The presence of myocardial fibrosis, which causes left ventricular dysfunction in RHD, might be utilized to determine options for treatment and might also be used to predict the outcome of interventions in patients with RHD. This emerging concept of myocardial fibrosis needs to be explored comprehensively in order to be optimally utilized in the treatment of RHD.

Myocardial Tissue-Level Characteristics of Adults With Metabolically Healthy Obesity

BACKGROUND

It remains unclear whether adults with metabolically healthy obesity (MHO) have altered myocardial tissue-level characteristics.

OBJECTIVES

This study aims to assess the subclinical myocardial tissue-level characteristics of adults with MHO.

METHODS

The EARLY-MYO-OBESITY (EARLY Assessment of MYOcardial Tissue Characteristics in OBESITY; NCT05277779) registry was a prospective, 3-center, cardiac imaging study of obese nondiabetic individuals without cardiac symptoms who underwent cardiac magnetic resonance. Myocardial tissue-level characteristics, including extracellular volume fraction (ECV) and native T2 values, were measured as indicators of myocardial fibrosis and edema. Global longitudinal peak systolic strain and early diastolic longitudinal strain rate were assessed by tissue tracking analysis to detect subclinical systolic and diastolic dysfunction.

RESULTS

A total of 120 participants were included: MHO (n = 32; mean age, 38 years; 41% men), metabolically healthy controls without obesity (n = 32; mean age: 37 years; 41% men), and metabolically unhealthy obesity (MUHO) (n = 56; mean age: 37 years; 55% men). The MHO group had higher ECV and native T2 values than healthy controls (both P < 0.001); furthermore, the ECV was higher in the MUHO group than in the MHO group (P = 0.002). The prevalence of myocardial fibrosis was 44% (14 of 32) in the MHO group and 71% (40 of 56) in the MUHO group. Although there was no intergroup difference in left ventricular ejection fraction, the MHO group had reduced global longitudinal peak systolic and early diastolic longitudinal strain rates, indicating subclinical systolic and diastolic dysfunction. Multivariate regression analysis identified increased body mass index to be an independent risk factor for myocardial fibrosis (OR: 6.28 [95% CI: 3.17-12.47]; P < 0.001).

CONCLUSIONS

This study provides the first evidence of subclinical myocardial tissue-level remodeling in adults with obesity, regardless of metabolic health. Early identification of cardiac impairment may facilitate preventive strategies against heart failure in the MHO population. (EARLY Assessment of MYOcardial Tissue Characteristics in OBESITY [EARLY-MYO-OBESITY]; NCT05277779).

Intrapericardial long non-coding RNA-Tcf21 antisense RNA inducing demethylation administration promotes cardiac repair

AIMS

Epicardium and epicardium-derived cells are critical players in myocardial fibrosis. Mesenchymal stem cell-derived extracellular vesicles (EVs) have been studied for cardiac repair to improve cardiac remodelling, but the actual mechanisms remain elusive. The aim of this study is to investigate the mechanisms of EV therapy for improving cardiac remodelling and develop a promising treatment addressing myocardial fibrosis.

METHODS AND RESULTS

Extracellular vesicles were intrapericardially injected for mice myocardial infarction treatment. RNA-seq, in vitro gain- and loss-of-function experiments, and in vivo studies were performed to identify targets that can be used for myocardial fibrosis treatment. Afterward, a lipid nanoparticle-based long non-coding RNA (lncRNA) therapy was prepared for mouse and porcine models of myocardial infarction treatment. Intrapericardial injection of EVs improved adverse myocardial remodelling in mouse models of myocardial infarction. Mechanistically, Tcf21 was identified as a potential target to improve cardiac remodelling. Loss of Tcf21 function in epicardium-derived cells caused increased myofibroblast differentiation, whereas forced Tcf21 overexpression suppressed transforming growth factor-β signalling and myofibroblast differentiation. LncRNA-Tcf21 antisense RNA inducing demethylation (TARID) that enriched in EVs was identified to up-regulate Tcf21 expression. Formulated lncRNA-TARID-laden lipid nanoparticles up-regulated Tcf21 expression in epicardium-derived cells and improved cardiac function and histology in mouse and porcine models of myocardial infarction.

CONCLUSION

This study identified Tcf21 as a critical target for improving cardiac fibrosis. Up-regulating Tcf21 by using lncRNA-TARID-laden lipid nanoparticles could be a promising way to treat myocardial fibrosis. This study established novel mechanisms underlying EV therapy for improving adverse remodelling and proposed a lncRNA therapy for cardiac fibrosis.

Inhibition of transglutaminase 2 (TG2) ameliorates ventricular fibrosis in isoproterenol-induced heart failure in rats

AIMS

Transglutaminase (TG) inhibitors represent promising therapeutic interventions in cardiac fibrosis and related dysfunctions. However, it remains unknown how TG inhibition, TG2 in particular, affects the signaling systems that drive pathological fibrosis. This study aimed to examine the effect TG inhibition by cystamine on the progression of isoproterenol (ISO)-induced cardiac fibrosis and dysfunction in rats.

MATERIALS AND METHODS

Cardiac fibrosis was established by intraperitoneal injection of ISO to rats (ISO group), followed by 6 weeks of cystamine injection (ISO + Cys group). The control groups were administered normal saline alone or with cystamine. Hemodynamics, lipid profile, liver enzymes, urea, and creatinine were assessed in conjunction with heart failure markers (serum NT-proANP and cTnI). Left ventricular (LV) and atrial (LA) fibrosis, total collagen content, and mRNA expression of profibrotic markers including TG2 were quantified by Masson's trichrome staining, LC-MS/MS and quantitative PCR, respectively.

KEY FINDINGS

Cystamine administration to ISO rats significantly decreased diastolic and mean arterial pressures, total cholesterol, triglycerides, LDL, liver enzymes, urea, and creatinine levels, while increasing HDL. NT-proANP and cTnI serum levels remained unchanged. In LV tissues, significant reductions in ISO-induced fibrosis and elevated total collagen content were achieved after cystamine treatment, together with a reduction in TG2 concentration. Reduced mRNA expression of several profibrotic genes (COL1A1, FN1, MMP-2, CTGF, periostin, CX43) was also evidenced in LV tissues of ISO rats upon cystamine administration, whereas TGF-β1 expression was depressed in LA tissues. Cystamine decreased TG2 mRNA expression in the LV of control rats, while LV expression of TG2 was relatively low in ISO rats irrespective of cystamine treatment.

SIGNIFICANCE

TG2 inhibition by cystamine in vivo exerted cardioprotective effects against ISO-induced cardiac fibrosis in rats decreasing the LV abundance of several profibrotic markers and the content of TG2 and collagen, suggesting that TG2 pharmacological inhibition could be beneficial to alleviate cardiac fibrosis.

Diabetes Mellitus and Heart Failure: Epidemiology, Pathophysiologic Mechanisms, and the Role of SGLT2 Inhibitors

Diabetes mellitus (DM) and heart failure (HF) are frequently encountered afflictions that are linked by a common pathophysiologic background. According to landmark studies, those conditions frequently coexist, and this interaction represents a poor prognostic indicator. Based on mechanistic studies, HF can be propagated by multiple pathophysiologic pathways, such as inflammation, oxidative stress, endothelial dysfunction, fibrosis, cardiac autonomic neuropathy, and alterations in substrate utilization. In this regard, DM may augment myocardial inflammation, fibrosis, autonomic dysfunction, and lipotoxicity. As the interaction between DM and HF appears critical, the new cornerstone in DM and HF treatment, sodium-glucose cotransporter-2 inhibitors (SGLT2i), may be able to revert the pathophysiology of those conditions and lead to beneficial HF outcomes. In this review, we aim to highlight the deleterious pathophysiologic interaction between DM and HF, as well as demonstrate the beneficial role of SGLT2i in this field.

GSK126 an inhibitor of epigenetic regulator EZH2 suppresses cardiac fibrosis by regulating the EZH2-PAX6-CXCL10 pathway

Myocardial fibrosis is a common pathological companion of various cardiovascular diseases. To date, the role of enhancer of zeste homolog 2 (EZH2) in cancer has been well demonstrated including in renal carcinoma and its inhibitors have entered the stage of phase I/II clinical trials. However, the precise mechanism of EZH2 in cardiac diseases is largely unclear. In the current study, we first found that EZH2 expression was increased in Ang-II-treated cardiac fibroblasts (CFs) and mouse heart homogenates following isoproterenol (ISO) administration for 21 days, respectively. Ang-II induces CFs activation and increased collagen-I, collagen-III, α-SMA, EZH2, and trimethylates lysine 27 on histone 3 (H3K27me3) expressions can be reversed by EZH2 inhibitor (GSK126) and EZH2 siRNA. The ISO-induced cardiac hypertrophy, and fibrosis in vivo which were also related to the upregulation of EZH2 and its downstream target, H3K27me3, could be recovered by GSK126. Furthermore, the upregulation of EZH2 induces the decrease of paired box 6 (PAX6) and C-X-C motif ligand 10 (CXCL10) "which" were also reversed by GSK126 treatment. In summary, the present evidence strongly suggests that GSK126 could be a therapeutic intervention, blunting the development and progression of myocardial fibrosis in an EZH2-PAX6-CXCL10-dependent manner.

Subtyping based on immune cell fractions reveal heterogeneity of cardiac fibrosis in end-stage heart failure

Background

A central issue hindering the development of effective anti-fibrosis drugs for heart failure is the unclear interrelationship between fibrosis and the immune cells. This study aims at providing precise subtyping of heart failure based on immune cell fractions, elaborating their differences in fibrotic mechanisms, and proposing a biomarker panel for evaluating intrinsic features of patients' physiological statuses through subtype classification, thereby promoting the precision medicine for cardiac fibrosis.

Methods

We inferred immune cell type abundance of the ventricular samples by a computational method (CIBERSORTx) based on ventricular tissue samples from 103 patients with heart failure, and applied K-means clustering to divide patients into two subtypes based on their immune cell type abundance. We also designed a novel analytic strategy: Large-Scale Functional Score and Association Analysis (LAFSAA), to study fibrotic mechanisms in the two subtypes.

Results

Two subtypes of immune cell fractions: pro-inflammatory and pro-remodeling subtypes, were identified. LAFSAA identified 11 subtype-specific pro-fibrotic functional gene sets as the basis for personalised targeted treatments. Based on feature selection, a 30-gene biomarker panel (ImmunCard30) established for diagnosing patient subtypes achieved high classification performance, with the area under the receiver operator characteristic curve corresponding to 0.954 and 0.803 for the discovery and validation sets, respectively.

Conclusion

Patients with the two subtypes of cardiac immune cell fractions were likely having different fibrotic mechanisms. Patients' subtypes can be predicted based on the ImmunCard30 biomarker panel. We envision that our unique stratification strategy revealed in this study will unravel advance diagnostic techniques for personalised anti-fibrotic therapy.

Cardiac fibroblasts and mechanosensation in heart development, health and disease

The term 'mechanosensation' describes the capacity of cells to translate mechanical stimuli into the coordinated regulation of intracellular signals, cellular function, gene expression and epigenetic programming. This capacity is related not only to the sensitivity of the cells to tissue motion, but also to the decryption of tissue geometric arrangement and mechanical properties. The cardiac stroma, composed of fibroblasts, has been historically considered a mechanically passive component of the heart. However, the latest research suggests that the mechanical functions of these cells are an active and necessary component of the developmental biology programme of the heart that is involved in myocardial growth and homeostasis, and a crucial determinant of cardiac repair and disease. In this Review, we discuss the general concept of cell mechanosensation and force generation as potent regulators in heart development and pathology, and describe the integration of mechanical and biohumoral pathways predisposing the heart to fibrosis and failure. Next, we address the use of 3D culture systems to integrate tissue mechanics to mimic cardiac remodelling. Finally, we highlight the potential of mechanotherapeutic strategies, including pharmacological treatment and device-mediated left ventricular unloading, to reverse remodelling in the failing heart.

The impact of myocardial fibrosis biomarkers in a heart failure population with atrial fibrillation—The HARVEST-Malmö study

Background

Several studies suggest that circulating biomarkers of myocardial fibrosis are associated with worse prognosis in subjects with atrial fibrillation (AF). Here, we aimed to explore associations between fibrosis biomarkers, prevalent AF, and left atrial volume (LAV) enlargement in subjects with heart failure (HF). Additionally, we evaluated the prognostic impact of fibrotic biomarkers in HF with co-existing AF.

Materials and methods

Patients hospitalized for HF (n = 316, mean age 75 years; 30% women) were screened for AF. Seven proteins previously associated with myocardial fibrosis [metalloproteinase inhibitor 4 (TIMP-4), suppression of tumorigenicity 2 (ST-2), galectin-3 (GAL-3), growth/differentiation factor-15 (GDF-15), and matrix metalloproteinase 2, 3, and 9 (MMP-3, MMP-3, and MMP-9, respectively)] were analyzed using a proximity extension assay. Proteins with significant Bonferroni-corrected associations with mortality and re-hospitalization risk were taken forward to multivariable Cox regression analyses. Further, Bonferroni-corrected multivariable logistic regression models were used to study associations between protein plasma levels, prevalent AF, and severely enlarged left atrial volume index (LAVI ≥ 48 ml/m²).

Results

Prevalent AF was observed in 194 patients at the hospitalization of whom 178 (92%) were re-hospitalized and 111 (57%) died during the follow-up period. In multivariable logistic regression models, increased plasma levels of TIMP-4, GDF-15, and ST-2 were associated with the prevalence of AF, whereas none of the seven proteins showed any significant association with severely enlarged LAVI. Increased plasma levels of five proteins yielded significant associations with all-cause mortality in patients with co-existing AF; TIMP-4 (HR 1.33; CI95% 1.07–1.66; p = 0.010), GDF-15 (HR 1.30; CI95% 1.05–1.62; p = 0.017), GAL-3 (HR 1.29; CI95% 1.03–1.61; p = 0.029), ST-2 (HR 1.48; CI95% 1.18–1.85; p < 0.001), and MMP-3 (HR 1.33; CI95% 1.09–1.63; p = 0.006). None of the proteins showed any significant association with re-hospitalization risk.

Conclusion

In this study, we were able to demonstrate that elevated levels of three plasma proteins previously linked to myocardial fibrosis are associated with prevalent AF in a HF population. Additionally, higher levels of five plasma proteins yielded an increased risk of mortality in the HF population with or without co-existing AF.

Comparative Evaluation of Inducible Cre Mouse Models for Fibroblast Targeting in the Healthy and Infarcted Myocardium

Several Cre recombinase transgenic mouse models have been generated for cardiac fibroblast (CF) tracking and heart regulation. However, there is still no consensus on the ideal mouse model to optimally identify and/or regulate these cells. Here, a comparative evaluation of the efficiency and specificity of the indirect reporter Cre-loxP system was carried out in three of the most commonly used fibroblast reporter transgenic mice (Pdgfra-CreERT2, Col1a1-CreERT2 and PostnMCM) under healthy and ischemic conditions, to determine their suitability in in vivo studies of cardiac fibrosis. We demonstrate optimal Cre recombinase activity in CF (but also, although moderate, in endothelial cells (ECs)) derived from healthy and infarcted hearts in the PDGFRa-creERT2 mouse strain. In contrast, no positive reporter signal was found in CF derived from the Col1a1-CreERT2 mice. Finally, in the PostnMCM line, fluorescent reporter expression was specifically detected in activated CF but not in EC, which leads us to conclude that it may be the most reliable model for future studies on cardiovascular disease. Importantly, no lethality or cardiac fibrosis were induced after tamoxifen administration at the established doses, either in healthy or infarcted mice of the three fibroblast reporter lineages. This study lays the groundwork for future efficient in vivo CF tracking and functional analyses.

Novel Therapies for the Treatment of Cardiac Fibrosis Following Myocardial Infarction

Cardiac fibrosis is a common pathological consequence of most myocardial diseases. It is associated with the excessive accumulation of extracellular matrix proteins as well as fibroblast differentiation into myofibroblasts in the cardiac interstitium. This structural remodeling often results in myocardial dysfunctions such as arrhythmias and impaired systolic function in patients with heart conditions, ultimately leading to heart failure and death. An understanding of the precise mechanisms of cardiac fibrosis is still limited due to the numerous signaling pathways, cells, and mediators involved in the process. This review article will focus on the pathophysiological processes associated with the development of cardiac fibrosis. In addition, it will summarize the novel strategies for anti-fibrotic therapies such as epigenetic modifications, miRNAs, and CRISPR technologies as well as various medications in cellular and animal models.

Automated Dual-energy Computed Tomography-based Extracellular Volume Estimation for Myocardial Characterization in Patients With Ischemic and Nonischemic Cardiomyopathy

OBJECTIVES

We aimed to validate and test a prototype algorithm for automated dual-energy computed tomography (DECT)-based myocardial extracellular volume (ECV) assessment in patients with various cardiomyopathies.

METHODS

This retrospective study included healthy subjects (n=9; 61±10 y) and patients with cardiomyopathy (n=109, including a validation cohort n=60; 68±9 y; and a test cohort n=49; 69±11 y), who had previously undergone cardiac DECT. Myocardial ECV was calculated using a prototype-based fully automated algorithm and compared with manual assessment. Receiver-operating characteristic analysis was performed to test the algorithm's ability to distinguish healthy subjects and patients with cardiomyopathy.

RESULTS

The fully automated method led to a significant reduction of postprocessing time compared with manual assessment (2.2±0.4 min and 9.4±0.7 min, respectively, P <0.001). There was no significant difference in ECV between the automated and manual methods ( P =0.088). The automated method showed moderate correlation and agreement with the manual technique ( r =0.68, intraclass correlation coefficient=0.66). ECV was significantly higher in patients with cardiomyopathy compared with healthy subjects, regardless of the method used ( P <0.001). In the test cohort, the automated method yielded an area under the curve of 0.98 for identifying patients with cardiomyopathies.

CONCLUSION

Automated ECV estimation based on DECT showed moderate agreement with the manual method and matched with previously reported ECV values for healthy volunteers and patients with cardiomyopathy. The automatically derived ECV demonstrated an excellent diagnostic performance to discriminate between healthy and diseased myocardium, suggesting that it could be an effective initial screening tool while significantly reducing the time of assessment.

A Simplified Herbal Formula Improves Cardiac Function and Reduces Inflammation in Mice Through the TLR-Mediated NF-κB Signaling Pathway

Nuanxinkang tablet (NXK), a Chinese herbal formula, can improve heart function and quality of life in patients with chronic heart failure (CHF). However, the mechanisms of action of NXK are not fully understood. In this study, we investigated the effects of NXK on inflammation in the CHF mouse model. This model was established by transverse aortic constriction (TAC) and treated with NXK for 8 weeks. Then, the cardiac function and myocardial fibrosis were evaluated. The monocytes/macrophages were evaluated by immunofluorescence. The mRNA levels of IL-1β, IL-6, TNF-α, ICAM-1, and VCAM-1 were measured by quantitative real-time polymerase chain reaction (qRT-PCR), while TLR4, MyD88, NF-κB p65, P-IκBα, TLR2, TLR7 and TLR9 protein levels were evaluated by Western blot. The results showed that NXK improved the left ventricular ejection fraction (LVEF) and left ventricular end-systolic dimension, reversed myocardial fibrosis, and inhibited pro-inflammatory (CD11b + Ly6C+) monocytes/macrophages in the TAC mouse model. NXK also reduced the mRNA and protein levels of the above markers. Taken together, NXK improved heart function and reduced inflammation through the TLR-mediated NF-κB signaling pathway, suggesting that it might be used as an innovative treatment strategy for CHF.

Downregulation of lncRNA Miat contributes to the protective effect of electroacupuncture against myocardial fibrosis

Background

Myocardial fibrosis changes the structure of myocardium, leads to cardiac dysfunction and induces arrhythmia and cardiac ischemia, threatening patients’ lives. Electroacupuncture at PC6 (Neiguan) was previously found to inhibit myocardial fibrosis. Long non-coding RNAs (lncRNAs) play a variety of regulatory functions in myocardial fibrosis, but whether electroacupuncture can inhibit myocardial fibrosis by regulating lncRNA has rarely been reported.

Methods

In this study, we constructed myocardial fibrosis rat models using isoproterenol (ISO) and treated rats with electroacupuncture at PC6 point and non-point as control. Hematoxylin–eosin, Masson and Sirius Red staining were performed to assess the pathological changes and collagen deposition. The expression of fibrosis-related markers in rat myocardial tissue were detected by RT-qPCR and Western blot. Miat, an important long non-coding RNA, was selected to study the regulation of myocardial fibrosis by electroacupuncture at the transcriptional and post-transcriptional levels. In post-transcriptional level, we explored the myocardial fibrosis regulation effect of Miat on the sponge effect of miR-133a-3p. At the transcriptional level, we studied the formation of heterodimer PPARG–RXRA complex and promotion of the TGF-β1 transcription.

Results

Miat was overexpressed by ISO injection in rats. We found that Miat can play a dual regulatory role in myocardial fibrosis. Miat can sponge miR-133a-3p in an Ago2-dependent manner, reduce the binding of miR-133a-3p target to the 3ʹUTR region of CTGF mRNA and improve the protein expression level of CTGF. In addition, it can also directly bind with PPARG protein, inhibit the formation of heterodimer PPARG–RXRA complex and then promote the transcription of TGF-β1. Electroacupuncture at PC6 point, but not at non-points, can reduce the expression of Miat, thus inhibiting the expression of CTGF and TGF-β1 and inhibiting myocardial fibrosis.

Conclusion

We revealed that electroacupuncture at PC6 point can inhibit the process of myocardial fibrosis by reducing the expression of lncRNA Miat, which is a potential therapeutic method for myocardial fibrosis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13020-022-00615-6.

Diabetes and Myocardial Fibrosis: A Systematic Review and Meta-Analysis

OBJECTIVES

This systematic review and meta-analysis investigated the association of diabetes and glycemic control with myocardial fibrosis (MF).

BACKGROUND

MF is associated with an increased risk of heart failure, coronary artery disease, arrhythmias, and death. Diabetes may influence the development of MF, but evidence is inconsistent.

METHODS

The authors searched EMBASE, Medline Ovid, Cochrane CENTRAL, Web of Science, and Google Scholar for observational and interventional studies investigating the association of diabetes, glycemic control, and antidiabetic medication with MF assessed by histology and cardiac magnetic resonance (ie, extracellular volume fraction [ECV%] and T₁ time).

RESULTS

A total of 32 studies (88% exclusively on type 2 diabetes) involving 5,053 participants were included in the systematic review. Meta-analyses showed that diabetes was associated with a higher degree of MF assessed by histological collagen volume fraction (n = 6 studies; mean difference: 5.80; 95% CI: 2.00-9.59) and ECV% (13 studies; mean difference: 2.09; 95% CI: 0.92-3.27), but not by native or postcontrast T₁ time. Higher glycosylated hemoglobin levels were associated with higher degrees of MF.

CONCLUSIONS

Diabetes is associated with higher degree of MF assessed by histology and ECV% but not by T₁ time. In patients with diabetes, worse glycemic control was associated with higher MF degrees. These findings mostly apply to type 2 diabetes and warrant further investigation into whether these associations are causal and which medications could attenuate MF in patients with diabetes.

Myocardial Parametric Mapping by Cardiac Magnetic Resonance Imaging in Pediatric Cardiology and Congenital Heart Disease

Parametric mapping, that is, a pixel-wise map of magnetic relaxation parameters, expands the diagnostic potential of cardiac magnetic resonance by enabling quantification of myocardial tissue-specific magnetic relaxation on an absolute scale. Parametric mapping includes T₁ mapping (native and postcontrast), T₂ and T₂* mapping, and extracellular volume measurements. The myocardial composition is altered in various disease states affecting its inherent magnetic properties and thus the myocardial relaxation times that can be directly quantified using parametric mapping. Parametric mapping helps in the diagnosis of nonfocal disease states and allows for longitudinal disease monitoring, evaluating therapeutic response (as in Thalassemia patients with iron overload undergoing chelation), and risk-stratification of certain diseases. In this review article, we describe various mapping techniques and their clinical utility in congenital heart disease. We will also review the available literature on normative values in children, the strengths, and weaknesses of these techniques. This review provides a starting point for pediatric cardiologists to understand and implement parametric mapping in their practice.

Arrhythmogenic Hearts in PKD2 Mutant Mice Are Characterized by Cardiac Fibrosis, Systolic, and Diastolic Dysfunctions

Autosomal dominant polycystic kidney disease (PKD) is a hereditary disorder affecting multiple organs, including the heart. PKD has been associated with many cardiac abnormalities including the arrhythmogenic remodeling in clinical evaluations. In our current study, we hypothesized that Pkd2 gene mutation results in structural and functional defects in the myocardium. The structural and functional changes of Pkd2 mutant hearts were analyzed in the myocardial-specific Pkd2 knockout (KO) mouse. We further assessed a potential role of TGF-b₁ signaling in the pathology of Pkd2-KO hearts. Hearts from age-matched 6-month-old MyH6•Pkd2 ^wt/wt (control or wild-type) and MyH6•Pkd2 ^flox/flox (mutant or Pkd2-KO) mice were used to study differential heart structure and function. Cardiac histology was used to study structure, and the "isolated working heart" system was adapted to mount and perfuse mouse heart to measure different cardiac parameters. We found that macrophage1 (M1) and macrophage 2 (M2) infiltration, transforming growth factor (TGF-b₁) and TGF-b₁ receptor expressions were significantly higher in Pkd2-KO, compared to wild-type hearts. The increase in the extracellular matrix in Pkd2-KO myocardium led to cardiac hypertrophy, interstitial and conduction system fibrosis, causing cardiac dysfunction with a predisposition to arrhythmia. Left ventricular (LV) expansion or compliance and LV filling were impaired in fibrotic Pkd2-KO hearts, resulted in diastolic dysfunction. LV systolic contractility and elastance decreased in fibrotic Pkd2-KO hearts, resulted in systolic dysfunction. Compared to wild-type hearts, Pkd2-KO hearts were less responsive to the pharmacological stress-test and changes in preload. In conclusion, Pkd2-KO mice had systolic and diastolic dysfunction with arrhythmogenic hearts.

Astaxanthin Ameliorates high-fat diet-induced cardiac damage and fibrosis by upregulating and activating SIRT1

This study evaluated the protective effect of astaxanthin (ASX) against high-fat diet (HFD)-induced cardiac damage and fibrosis in rats and examined if the mechanism of protection involves modulating SIRT1. Rat were divided into 5 groups (n = 10/group) as: 1) control: fed normal diet (3.82 kcal/g), 2) control + ASX (200 mg/kg/orally), 3) HFD: fed HFD (4.7 kcal/g), 4) HFD + ASX (200 mg/kg/orally), and HFD + ASX + EX-527 (1 mg/kg/i.p) (a selective SIRT1 inhibitor). All treatments were conducted for 14 weeks. Administration of ASX reduced cardiomyocyte damage, inhibited inflammatory cell infiltration, preserved cardiac fibers structure, prevented collagen deposition and protein levels of TGF-β 1 in the left ventricles (LVs) of HFD-fed rats. In the LVs of both the control and HFD-fed rat, ASX significantly reduced levels of reactive oxygen species (ROS), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and p-smad2/3 (Lys19) but increased the levels of glutathione (GSH), catalase, and manganese superoxide dismutase (MnSOD). Concomitantly, it increased the nuclear activity of Nrf2 and reduced that of NF-κB p65. Furthermore, administration of ASX to both the control and HFD-fed rats increased total and nuclear levels of SIRT1, stimulated the nuclear activity of SIRT1, and reduced the acetylation of Nrf2, NF-κB p65, and Smad3. All these cardiac beneficial effects of ASX in the HFD-fed rats were abolished by co-administration of EX-527. In conclusion, ASX stimulates antioxidants and inhibits markers of inflammation under basal and HFD conditions. The mechanism of protection involves, at least, activation SIRT1 signaling.

Perspective on Stem Cell Therapy in Organ Fibrosis: Animal Models and Human Studies

Tissue fibrosis is characterized by excessive deposition of extracellular matrix (ECM) components that result from the disruption of regulatory processes responsible for ECM synthesis, deposition, and remodeling. Fibrosis develops in response to a trigger or injury and can occur in nearly all organs of the body. Thus, fibrosis leads to severe pathological conditions that disrupt organ architecture and cause loss of function. It has been estimated that severe fibrotic disorders are responsible for up to one-third of deaths worldwide. Although intensive research on the development of new strategies for fibrosis treatment has been carried out, therapeutic approaches remain limited. Since stem cells, especially mesenchymal stem cells (MSCs), show remarkable self-renewal, differentiation, and immunomodulatory capacity, they have been intensively tested in preclinical studies and clinical trials as a potential tool to slow down the progression of fibrosis and improve the quality of life of patients with fibrotic disorders. In this review, we summarize in vitro studies, preclinical studies performed on animal models of human fibrotic diseases, and recent clinical trials on the efficacy of allogeneic and autologous stem cell applications in severe types of fibrosis that develop in lungs, liver, heart, kidney, uterus, and skin. Although the results of the studies seem to be encouraging, there are many aspects of cell-based therapy, including the cell source, dose, administration route and frequency, timing of delivery, and long-term safety, that remain open areas for future investigation. We also discuss the contemporary status, challenges, and future perspectives of stem cell transplantation for therapeutic options in fibrotic diseases as well as we present recent patents for stem cell-based therapies in organ fibrosis.

Hydrogen Sulfide Attenuates Angiotensin II-Induced Cardiac Fibroblast Proliferation and Transverse Aortic Constriction-Induced Myocardial Fibrosis through Oxidative Stress Inhibition via Sirtuin 3

Sirtuin 3 (SIRT3) is critical in mitochondrial function and oxidative stress. Our present study investigates whether hydrogen sulfide (H₂S) attenuated myocardial fibrosis and explores the possible role of SIRT3 on the protective effects. Neonatal rat cardiac fibroblasts were pretreated with NaHS followed by angiotensin II (Ang II) stimulation. SIRT3 was knocked down with siRNA technology. SIRT3 promoter activity and expression, as well as mitochondrial function, were measured. Male wild-type (WT) and SIRT3 knockout (KO) mice were intraperitoneally injected with NaHS followed by transverse aortic constriction (TAC). Myocardium sections were stained with Sirius red. Hydroxyproline content, collagen I and collagen III, α-smooth muscle actin (α-SMA), and dynamin-related protein 1 (DRP1) expression were measured both in vitro and in vivo. We found that NaHS enhanced SIRT3 promoter activity and increased SIRT3 mRNA expression. NaHS inhibited cell proliferation and hydroxyproline secretion, decreased collagen I, collagen III, α-SMA, and DRP1 expression, alleviated oxidative stress, and improved mitochondrial respiration function and membrane potential in Ang II-stimulated cardiac fibroblasts, which were unavailable after SIRT3 was silenced. In vivo, NaHS reduced hydroxyproline content, ameliorated perivascular and interstitial collagen deposition, and inhibited collagen I, collagen III, and DRP1 expression in the myocardium of WT mice but not SIRT3 KO mice with TAC. Altogether, NaHS attenuated myocardial fibrosis through oxidative stress inhibition via a SIRT3-dependent manner.

ST-segment resolution as a marker for severe myocardial fibrosis in ST-segment elevation myocardial infarction

Objective

To investigate the relationship between ST-segment resolution (STR) and myocardial scar thickness after percutaneous coronary intervention (PCI) in patients with ST-segment elevation myocardial infarction (STEMI).

Methods

Forty-two STEMI patients with single-branch coronary artery stenosis or occlusion were enrolled. ST-segment elevations were measured at emergency admission and at 24 h after PCI. Late gadolinium-enhanced cardiac magnetic resonance imaging (CMR-LGE) was performed 7 days after PCI to evaluate myocardial scars. Statistical analyses were performed to assess the utility of STR to predict the development of transmural (> 75%) or non-transmural (< 75%) myocardial scars, according to previous study.

Results

The sensitivity and specificity of STR for predicting transmural scars were 96% and 88%, respectively, at an STR cut-off value of 40.15%. The area under the curve was 0.925. Multivariate logistic proportional hazards regression analysis disclosed that patients with STR < 40.15% had a 170.90-fold higher probability of developing transmural scars compared with patients with STR ≥ 40.15%. Pearson correlation and linear regression analyses showed STR percentage was significantly associated with myocardial scar thickness and size.

Conclusion

STR < 40.15% at 24 h after PCI may provide meaningful diagnostic information regarding the extent of myocardial scarification in STEMI patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12872-021-02269-y.

Need for Speed: The Importance of Physiological Strain Rates in Determining Myocardial Stiffness

The heart is viscoelastic, meaning its compliance is inversely proportional to the speed at which it stretches. During diastolic filling, the left ventricle rapidly expands at rates where viscoelastic forces impact ventricular compliance. In heart disease, myocardial viscoelasticity is often increased and can directly impede diastolic filling to reduce cardiac output. Thus, treatments that reduce myocardial viscoelasticity may provide benefit in heart failure, particularly for patients with diastolic heart failure. Yet, many experimental techniques either cannot or do not characterize myocardial viscoelasticity, and our understanding of the molecular regulators of viscoelasticity and its impact on cardiac performance is lacking. Much of this may stem from a reliance on techniques that either do not interrogate viscoelasticity (i.e., use non-physiological rates of strain) or techniques that compromise elements that contribute to viscoelasticity (i.e., skinned or permeabilized muscle preparations that compromise cytoskeletal integrity). Clinically, cardiac viscoelastic characterization is challenging, requiring the addition of strain-rate modulation during invasive hemodynamics. Despite these challenges, data continues to emerge demonstrating a meaningful contribution of viscoelasticity to cardiac physiology and pathology, and thus innovative approaches to characterize viscoelasticity stand to illuminate fundamental properties of myocardial mechanics and facilitate the development of novel therapeutic strategies.

Cardiac Contractility Modulation in Patients with Ischemic versus Non-ischemic Cardiomyopathy: Results from the MAINTAINED Observational Study

BACKGROUND

Cardiac contractility modulation (CCM) is an FDA-approved device-based therapy for patients with systolic heart failure and normal QRS width who are symptomatic despite optimal drug therapy. The purpose of this study was to compare the long-term therapeutic effects of CCM therapy in patients with ischemic (ICM) versus non-ischemic cardiomyopathy (NICM).

METHODS

Changes in NYHA class, KDIGO CKD stage, left ventricular ejection fraction (LVEF), tricuspid annular plane systolic excursion (TAPSE), and NT-proBNP levels were compared as functional parameters. Moreover, observed mortality rates at 1 and 3 years were compared to those predicted by the MAGGIC heart failure risk score, and observed mortality rates were compared between groups for the entire follow-up period.

RESULTS

One hundred and seventy-four consecutive patients with chronic heart failure and CCM device implantation between 2002 and 2019 were included in this retrospective analysis. LVEF was significantly higher in NICM patients after 3 years of CCM therapy (35 ± 9 vs. 30 ± 9%; p = 0.0211), and after 5 years, also TAPSE of NICM patients was significantly higher (21 ± 5 vs. 18 ± 5%; p = 0.0437). There were no differences in other effectiveness parameters. Over the entire follow-up period, 35% of all patients died (p = 0.81); only in ICM patients, mortality was lower than predicted at 3 years (35 vs. 43%, p = 0.0395).

CONCLUSIONS

Regarding improvement of biventricular systolic function, patients with NICM appear to benefit particularly from CCM therapy.

Mitral Valve Prolapse and Its Motley Crew-Syndromic Prevalence, Pathophysiology, and Progression of a Common Heart Condition

Mitral valve prolapse (MVP) is a commonly occurring heart condition defined by enlargement and superior displacement of the mitral valve leaflet(s) during systole. Although commonly seen as a standalone disorder, MVP has also been described in case reports and small studies of patients with various genetic syndromes. In this review, we analyzed the prevalence of MVP within syndromes where an association to MVP has previously been reported. We further discussed the shared biological pathways that cause MVP in these syndromes, as well as how MVP in turn causes a diverse array of cardiac and noncardiac complications. We found 105 studies that identified patients with mitral valve anomalies within 18 different genetic, developmental, and connective tissue diseases. We show that some disorders previously believed to have an increased prevalence of MVP, including osteogenesis imperfecta, fragile X syndrome, Down syndrome, and Pseudoxanthoma elasticum, have few to no studies that use up-to-date diagnostic criteria for the disease and therefore may be overestimating the prevalence of MVP within the syndrome. Additionally, we highlight that in contrast to early studies describing MVP as a benign entity, the clinical course experienced by patients can be heterogeneous and may cause significant cardiovascular morbidity and mortality. Currently only surgical correction of MVP is curative, but it is reserved for severe cases in which irreversible complications of MVP may already be established; therefore, a review of clinical guidelines to allow for earlier surgical intervention may be warranted to lower cardiovascular risk in patients with MVP.

Cardiac Fibrosis and Fibroblasts

Cardiac fibrosis is the excess deposition of extracellular matrix (ECM), such as collagen. Myofibroblasts are major players in the production of collagen, and are differentiated primarily from resident fibroblasts. Collagen can compensate for the dead cells produced by injury. The appropriate production of collagen is beneficial for preserving the structural integrity of the heart, and protects the heart from cardiac rupture. However, excessive deposition of collagen causes cardiac dysfunction. Recent studies have demonstrated that myofibroblasts can change their phenotypes. In addition, myofibroblasts are found to have functions other than ECM production. Myofibroblasts have macrophage-like functions, in which they engulf dead cells and secrete anti-inflammatory cytokines. Research into fibroblasts has been delayed due to the lack of selective markers for the identification of fibroblasts. In recent years, it has become possible to genetically label fibroblasts and perform sequencing at single-cell levels. Based on new technologies, the origins of fibroblasts and myofibroblasts, time-dependent changes in fibroblast states after injury, and fibroblast heterogeneity have been demonstrated. In this paper, recent advances in fibroblast and myofibroblast research are reviewed.

Targeting fibrosis in the failing heart with nanoparticles

Heart failure (HF) is a clinical syndrome characterized by typical symptoms and signs caused by a structural and/or functional cardiac abnormality, resulting in a reduced cardiac output and/or elevated intracardiac pressures at rest or during stress. Due to increasing incidence, prevalence and, most importantly mortality, HF is a healthcare burden worldwide, despite the improvement of treatment options and effectiveness. Acute and chronic cardiac injuries trigger the activation of neurohormonal, inflammatory, and mechanical pathways ultimately leading to fibrosis, which plays a key role in the development of cardiac dysfunction and HF. The use of nanoparticles for targeted drug delivery would greatly improve therapeutic options to identify, prevent and treat cardiac fibrosis. In this review we will highlight the mechanisms of cardiac fibrosis development to depict the pathophysiological features for passive and active targeting of acute and chronic cardiac fibrosis with nanoparticles. Then we will discuss how cardiomyocytes, immune and inflammatory cells, fibroblasts and extracellular matrix can be targeted with nanoparticles to prevent or restore cardiac dysfunction and to improve the molecular imaging of cardiac fibrosis.

HPLC-QTOF/MS-based metabolomics to explore the molecular mechanisms of Yiqi Fumai Lyophilized Injection in heart failure mice

Chronic heart failure is a common and fatal disease triggered by loss of normal cardiac function. Yiqi Fumai Lyophilized Injection is widely used in the treatment of cardiovascular diseases, especially chronic heart failure. In this study, a model of chronic heart failure in mice was established with permanent coronary artery ligation followed by Yiqi Fumai Lyophilized Injection intervention for 14 days. Then, the endogenous metabolites of mice plasma and urine samples were screened through nontargeted metabolomics techniques. The results indicated that Yiqi Fumai Lyophilized Injection treatment changed the metabolic pattern of chronic heart failure and regulated valine, leucine, and isoleucine biosynthesis, taurine and hypotaurine metabolism, histidine metabolism and arginine biosynthesis, etc. Finally, the cardioprotective mechanism of Yiqi Fumai Lyophilized Injection was further verified in the mouse model of chronic heart failure and angiotensin II-induced cardiac fibroblasts based on metabolomics. The results showed that Yiqi Fumai Lyophilized Injection could inhibit myocardial fibrosis to improve chronic heart failure. This study firstly elucidated the metabolic network and pathways regulated by Yiqi Fumai Lyophilized Injection, which might facilitate the realization of the clinically accurate application of Yiqi Fumai Lyophilized Injection in the treatment of chronic heart failure.

New Targets in Heart Failure Drug Therapy

Despite recent advances in chronic heart failure management (either pharmacological or non-pharmacological), the prognosis of heart failure (HF) patients remains poor. This poor prognosis emphasizes the need for developing novel pathways for testing new HF drugs, beyond neurohumoral and hemodynamic modulation approaches. The development of new drugs for HF therapy must thus necessarily focus on novel approaches such as the direct effect on cardiomyocytes, coronary microcirculation, and myocardial interstitium. This review summarizes principal evidence on new possible pharmacological targets for the treatment of HF patients, mainly focusing on microcirculation, cardiomyocyte, and anti-inflammatory therapy.

Starch based hydrogel NPs loaded by anthocyanins might treat glycogen storage at cardiomyopathy in animal fibrotic model

Many reports have been published recently confirmed the limitation of cargo molecules delivered into the heart. This failure is mostly associated with lymphatic or vascular channels washing or to the immune system recognition. Delivery of anthocyanins by encapsulation may augment it retention in the heart at early time points as the capsules are too large to wash out by lymphatic or venous channels and the physical structure of the capsule may shield the anthocyanins from immunoglobulins and cellular components of the immune system. In the current study, the cardiac dysfunction was induced by using carbon tetrachloride and then animal were treated orally by using anthocyanins incorporated into hydrogel NPs twice time /week for 4 weeks. The results showed anthocyanin loaded hydrogel NPs has ability to re-maintain the glycogen content in the liver and heart tissues of fibrotic group (13 ± 1.4 and 5 ± 0.7 μmol glucose/g tissue). Additionally, MDA and hydroxyproline were significantly reduced. PAS stain showed depletion of glycogen granules from heart tissue. It is concluded that starch based hydrogel loaded by anthocyanins can improve histological cardiac functions after their injury .