Cardiac fibrosis: Cell biological mechanisms, molecular pathways and therapeutic opportunities

miR-210 overexpression increases pressure overload-induced cardiac fibrosis

Aortic stenosis, a common valvular heart disease, can lead to left ventricular pressure overload, triggering pro-fibrotic responses in the heart. miR-210 is a microRNA that responds to hypoxia and ischemia and plays a role in immune regulation and in cardiac remodeling upon myocardial infarction. This study investigated the effects of miR-210 on cardiac fibrosis caused by pressure overload. Using a mouse model with inducible miR-210 over-expression, we subjected mice to transverse aortic constriction (TAC) to induce pressure overload. Mice with miR-210 over-expression developed eccentric hypertrophy, heightened expression of hypertrophic markers (Nppa and Nppb) and increased cross sectional area of cardiomyocytes, impacting the free wall of the left ventricle. These findings suggest that miR-210 worsens cardiac dysfunction. Furthermore, miR-210 over-expression led to a more robust and sustained inflammatory response in the heart, increased interstitial and perivascular fibrosis, and activation of myofibroblasts. miR-210 also promoted angiogenesis. In vitro, cardiac fibroblasts over-expressing miR-210 showed increased adhesion, wound healing and migration capacity. Our results demonstrate that miR-210 contributes to adverse cardiac remodeling in response to pressure overload, including eccentric hypertrophy, inflammation, and fibrosis.

Mitochondrial dynamics and metabolism in macrophages for cardiovascular disease: A review

BACKGROUND

Mitochondria regulate macrophage function, affecting cardiovascular diseases like atherosclerosis and heart failure. Their dynamics interact with macrophage cell death mechanisms, including apoptosis and necroptosis.

PURPOSE

This review explores how mitochondrial dynamics and metabolism influence macrophage inflammation and cell death in CVDs, highlighting therapeutic targets for enhancing macrophage resilience and reducing CVD pathology, while examining molecular pathways and pharmacological agents involved.

STUDY DESIGN

This is a narrative review that integrates findings from various studies on mitochondrial dynamics and metabolism in macrophages, their interactions with the endoplasmic reticulum (ER) and Golgi apparatus, and their implications for CVDs. The review also considers the potential therapeutic effects of pharmacological agents on these pathways.

METHODS

The review utilizes a comprehensive literature search to identify relevant studies on mitochondrial dynamics and metabolism in macrophages, their role in CVDs, and the effects of pharmacological agents on these pathways. The selected studies are analyzed and synthesized to provide insights into the complex relationships between mitochondria, the ER, and Golgi apparatus, and their implications for macrophage function and fate.

RESULTS

The review reveals that mitochondrial metabolism intertwines with cellular architecture and function, particularly through its intricate interactions with the ER and Golgi apparatus. Mitochondrial-associated membranes (MAMs) facilitate Ca2+ transfer from the ER to mitochondria, maintaining mitochondrial homeostasis during ER stress. The Golgi apparatus transports proteins crucial for inflammatory signaling, contributing to immune responses. Inflammation-induced metabolic reprogramming in macrophages, characterized by a shift from oxidative phosphorylation to glycolysis, underscores the multifaceted role of mitochondrial metabolism in regulating immune cell polarization and inflammatory outcomes. Notably, mitochondrial dysfunction, marked by heightened reactive oxygen species generation, fuels inflammatory cascades and promotes cell death, exacerbating CVD pathology. However, pharmacological agents such as Metformin, Nitazoxanide, and Galanin emerge as potential therapeutic modulators of these pathways, offering avenues for mitigating CVD progression.

CONCLUSION

This review highlights mitochondrial dynamics and metabolism in macrophage inflammation and cell death in CVDs, suggesting therapeutic targets to improve macrophage resilience and reduce pathology, with new pharmacological agents offering treatment opportunities.

Latest developments of microphysiological systems (MPS) in aging-related and geriatric diseases research: A review

Aging is a gradual and irreversible process accompanied by the decline in tissue function and a significantly increased risk of various aging-related and geriatric diseases. Especially in the paradoxical context of accelerated global aging and the widespread emergence of pandemics, aging-related and geriatric diseases have become leading causes of individual mortality and disability, drawing increasing attention from researchers and investors alike. Despite the utility of current in vitro systems and in vivo animal models for studying aging, these approaches are limited by insurmountable inherent constraints. In response, microphysiological systems (MPS), leveraging advances in tissue engineering and microfluidics, have emerged as highly promising platforms. MPS are capable of replicating key features of the tissue microenvironment within microfabricated devices, offering biomimetic tissue culture conditions that enhance the in vitro simulation of intact or precise human body structure and function. This capability improves the predictability of clinical trial outcomes while reducing time and cost. In this review, we focus on recent advancements in MPS used to study age-related and geriatric diseases, with particular emphasis on the application of organoids and organ-on-a-chip technologies in understanding cardiovascular diseases, cerebrovascular diseases, neurodegenerative diseases, fibrotic diseases, locomotor and sensory degenerative disorders, and rare diseases. And we aim to provide readers with critical guidelines and an overview of examples for modeling age-related and geriatric diseases using MPS, exploring mechanisms, treatments, drug screening, and other subsequent applications, from a physiopathological perspective, emphasizing the characteristic of age-related and geriatric diseases and their established correlations with the aging process. We also discuss the limitations of current models and propose future directions for MPS in aging research, highlighting the potential of interdisciplinary approaches to address unresolved challenges in the field.

Ultrasmall PtIr Bimetallic Nanozyme Treats Myocardial Infarction via Ischemic/Inflammatory Cardiac Microenvironment Remodeling

Myocardial infarction (MI) poses a serious threat to human health. MI induces oxidative damage and inflammation, leading to myocardial death, scarring, and ventricular remodeling. Nanozymes have shown potential to alleviate reactive oxygen species (ROS)-induced damage and treat cardiovascular diseases. In this study, we developed an ultrasmall PtIr bimetallic nanozyme to treat MI. The PtIr nanozyme exhibited robust superoxide dismutase- and catalase-mimicking catalytic activities, modulating the conversion of excessive ROS into harmless products. Furthermore, PtIr nanozyme treatment reduced ROS levels and apoptosis in human cardiomyocyte AC16 cells under oxidative stress in vitro, while increasing the expression of cardiomyocyte-related functional genes, including cTnT, cTnI, Cx43, and ACTN2. It also maintained the intracellular mitochondrial membrane potential, increased mitochondrial activity, and protected mitochondrial structure. In a rat MI model, the PtIr nanozyme attenuated neutrophil extracellular trap formation, apoptosis, and inflammation in the infarcted heart 1 week postadministration. Four weeks postadministration, the PtIr nanozyme significantly enhanced cardiomyocyte activity and functional connectivity, reduced infarct size and fibrosis levels, and increased microvascular density compared with phosphate-buffered saline or Ir nanozyme treatment. Proteomic analysis revealed that proteins associated with energy metabolism, mitochondrial function, and myocardial contraction were upregulated, while multiple pathways related to mitochondrial function and energy metabolism, such as fatty acid β-oxidation and the citric acid cycle, were enriched in the PtIr nanozyme injection group. These results suggest that the PtIr nanozyme remodels the infarct microenvironment by modulating mitochondrial function and the inflammatory response, repairing the damaged myocardium, and improving cardiac function. Our findings highlight a promising therapeutic strategy for MI.

Rescue of mitochondrial dysfunction through alteration of extracellular matrix composition in barth syndrome cardiac fibroblasts

Fibroblast-ECM (dys)regulation is associated with a plethora of diseases. The ECM acts as a reservoir of inflammatory factors and cytokines that mediate molecular mechanisms within cardiac cell populations. The role of ECM-mitochondria crosstalk in the development and progression of cardiac disorders remains uncertain. We evaluated the influence of ECM produced by stromal cells from patients with the mitochondrial cardiomyopathy (Barth syndrome, BTHS) and unaffected healthy controls on cardiac fibroblast (CF) metabolic function. To do this, cell-derived matrices CDMs were generated from BTHS and healthy human pluripotent stem cell-derived CFs (hPSC-CF) and used as cell culture substrates. BTHS CDMs negatively impacted the mitochondrial function of healthy hPSC-CFs while healthy CDMs improved mitochondrial function in BTHS hPSC-CFs. Mass spectrometry comparisons identified 5 matrisome proteins differentially expressed in BTHS compared to healthy CDM. Our results highlight a key role for the ECM in disease through its impact on mitochondrial function.

Decoding the regulatory roles of circular RNAs in cardiac fibrosis

Cardiovascular diseases (CVDs) are the primary cause of death globally. The evolution of nearly all types of CVDs is characterized by a common theme: the emergence of cardiac fibrosis. The precise mechanisms that trigger cardiac fibrosis are still not completely understood. In recent years, a type of non-coding regulatory RNA molecule known as circular RNAs (circRNAs) has been reported. These molecules are produced during back splicing and possess significant biological capabilities, such as regulating microRNA activity, serving as protein scaffolds and recruiters, competing with mRNA, forming circR-loop structures to modulate transcription, and translating polypeptides. Furthermore, circRNAs exhibit a substantial abundance, notable stability, and specificity of tissues, cells, and time, endowing them with the potential as biomarkers, therapeutic targets, and therapeutic agents. CircRNAs have garnered growing interest in the field of CVDs. Recent investigations into the involvement of circRNAs in cardiac fibrosis have yielded encouraging findings. This study aims to provide a concise overview of the existing knowledge about the regulatory roles of circRNAs in cardiac fibrosis.

Targeting cardiac fibrosis with Chimeric Antigen Receptor-Engineered Cells

Cardiac fibrosis poses a significant challenge in cardiovascular diseases due to its intricate pathogenesis, and there is currently no standardized and effective treatment approach. The fibrotic process entails the involvement of various cell types and molecular mechanisms, such as fibroblast activation and proliferation, increased collagen synthesis, and extracellular matrix rearrangement. Traditional therapies often fall short in efficacy or carry substantial side effects. However, recent studies have shown that Chimeric Antigen Receptor T (CAR-T) cells can selectively target and eliminate activated cardiac fibroblasts (CFs) in mice, leading to reduced cardiac fibrosis and improved myocardial tissue compliance. This breakthrough presents a new and promising avenue for treating cardiac fibrosis. Currently, CAR-T cell-based therapy for cardiac fibrosis is undergoing animal experimentation, indicating ample scope for enhancement. Future investigations could explore the application of CAR cell therapy in cardiac fibrosis treatment, including the potential of CAR-natural killer (CAR-NK) cells and CAR macrophages (CAR-M), offering novel insights and strategies for combating cardiac fibrosis.

Autophagy and Its Association with Macrophages in Clonal Hematopoiesis Leading to Atherosclerosis

Atherosclerosis, a chronic inflammatory disease characterized by lipid accumulation and immune cell infiltration, is linked to plaque formation and cardiovascular events. While traditionally associated with lipid metabolism and endothelial dysfunction, recent research highlights the roles of autophagy and clonal hematopoiesis (CH) in its pathogenesis. Autophagy, a cellular process crucial for degrading damaged components, regulates macrophage homeostasis and inflammation, both of which are pivotal in atherosclerosis. In macrophages, autophagy influences lipid metabolism, cytokine regulation, and oxidative stress, helping to prevent plaque instability. Defective autophagy exacerbates inflammation, impairs cholesterol efflux, and accelerates disease progression. Additionally, autophagic processes in endothelial cells and smooth muscle cells further contribute to atherosclerotic pathology. Recent studies also emphasize the interplay between autophagy and CH, wherein somatic mutations in genes like TET2, JAK2, and DNMT3A drive immune cell expansion and enhance inflammatory responses in atherosclerotic plaques. These mutations modify macrophage function, intensifying the inflammatory environment and accelerating atherosclerosis. Chaperone-mediated autophagy (CMA), a selective form of autophagy, also plays a critical role in regulating macrophage inflammation by degrading pro-inflammatory cytokines and oxidized low-density lipoprotein (ox-LDL). Impaired CMA activity leads to the accumulation of these substrates, activating the NLRP3 inflammasome and worsening inflammation. Preclinical studies suggest that pharmacologically activating CMA may mitigate atherosclerosis progression. In animal models, reduced CMA activity accelerates plaque instability and increases inflammation. This review highlights the importance of autophagic regulation in macrophages, focusing on its role in inflammation, plaque formation, and the contributions of CH. Building upon current advances, we propose a hypothesis in which autophagy, programmed cell death, and clonal hematopoiesis form a critical intrinsic axis that modulates the fundamental functions of macrophages, playing a complex role in the development of atherosclerosis. Understanding these mechanisms offers potential therapeutic strategies targeting autophagy and inflammation to reduce the burden of atherosclerotic cardiovascular disease.

Deciphering myocardial fibrosis: a comprehensive bibliometric analysis of mechanism over the period 1992-2023

BACKGROUND

Myocardial fibrosis is a critical link in preventing the progression of heart disease. This study conducted a bibliometric analysis of its mechanism to identify trends and hotspots, aiming to provide valuable references for heart disease prevention and treatment.

METHODS

This research relies on the Web of Science Core Collection, capturing all related publications on the mechanism of myocardial fibrosis up to November 11, 2023. For the bibliometric analysis, CiteSpace 6.2.R5 (64-bit) and VOSviewer 1.6.19 software tools were utilized.

RESULTS

The mechanism of myocardial fibrosis research involves 14,931 authors from 2,370 institutions in 71 countries/regions, resulting in 2,431 published studies. Nattel Stanley is the most prolific author, while Francogianis Ng is noted for the highest co-publication frequency. The United States leads in countries/regions, with the University of California System being the top institution. Cardiovascular Research is a primary outlet for new studies, and Circulation is a key reference in this research community. Current research primarily examines how myocardial fibrosis contributes to heart failure, myocardial infarction, and myocardial hypertrophy. This emerging field also explores the role of fibroblasts in myocardial injury and investigates innovative treatments to reduce myocardial fibrosis.

CONCLUSIONS

Preventing myocardial fibrosis is a crucial strategy in the fight against heart disease. This study utilises bibliometric analysis to explore the vast array of literature on the mechanism of myocardial fibrosis, mapping the research landscape and provide literature references for potential breakthroughs in heart disease prevention and treatment strategies.

Fibroblast-Restricted Inflammasome Activation Promotes Atrial Fibrillation and Heart Failure With Diastolic Dysfunction

Atrial fibrillation (AF) often coexists with heart failure, both involving inflammatory signaling and cardiac fibroblasts. To understand the role of fibroblast NLR family pyrin domain containing 3 (NLRP3) inflammasome in cardiac function, we found that NLRP3 was up-regulated in atrial fibroblasts from AF patients. Fibroblast-specific activation of NLRP3 in mice induced AF-promoting atrial myopathy and heart failure with diastolic dysfunction, accompanied by increased fibrosis, and reduced conduction velocity. Knockdown of NLRP3 prevented the AF-promoting atrial substrate and cardiomyopathy in the context of NLRP3 activation in fibroblasts. We identify the fibroblast NLRP3 inflammasome as a key pathway governing the promotion of proarrhythmic fibrosis in AF and cardiomyopathy.

Dressed in Collagen: 2D and 3D Cardiac Fibrosis Models

Cardiovascular diseases (CVD), the leading cause of death worldwide, and their strong association with fibrosis highlight the pressing need for innovative antifibrotic therapies. In vitro models have emerged as valuable tools for replicating cardiac fibrosis 'in a dish', facilitating the study of disease mechanisms and serving as platforms for drug testing and development. These in vitro systems encompass 2D and 3D models, each with its own limitations and advantages. 2D models offer high reproducibility, cost-effectiveness, and high-throughput capabilities, but they oversimplify the complex fibrotic environment. On the other hand, 3D models provide greater biological relevance but are more complex, harder to reproduce, and less suited for high-throughput screening. The choice of model depends on the specific research question and the stage of drug development. Despite significant progress, challenges remain, including the integration of immune cells in cardiac fibrosis and optimizing the scalability and throughput of highly biomimetic systems. Herein, we review recent in vitro cardiac fibrosis models, with a focus on their shared characteristics and remaining challenges, and explore how in vitro fibrosis models of other organs could inspire novel approaches in cardiac research, showcasing potential strategies that could be adapted to refine myocardial fibrosis models.

From Bench to Bedside: Translational Approaches to Cardiotoxicity in Breast Cancer, Lung Cancer, and Lymphoma Therapies

Cardiotoxicity represents a critical challenge in cancer therapy, particularly in the treatment of thoracic tumors, such as lung cancer and lymphomas, as well as breast cancer. These malignancies stand out for their high prevalence and the widespread use of cardiotoxic treatments, such as chemotherapy, radiotherapy, and immunotherapy. This work underscores the importance of preclinical models in uncovering the mechanisms of cardiotoxicity and developing targeted prevention and mitigation strategies. In vitro models provide valuable insights into cellular processes, enabling the observation of changes in cell viability and function following exposure to various drugs or ionizing radiation. Complementarily, in vivo animal models offer a broader perspective, allowing for evaluating of both short- and long-term effects and a better understanding of chronic toxicity and cardiac diseases. By integrating these approaches, researchers can identify potential mechanisms of cardiotoxicity and devise effective prevention strategies. This analysis highlights the central role of preclinical models in advancing knowledge of cardiotoxic effects associated with common therapeutic regimens for thoracic and breast cancers.

Application of Cerium Oxide Nanozymes (CeONZs) in Human Pluripotent Stem Cell-Derived Cardiomyocytes

Cardiovascular diseases (CVDs) are a leading cause of death globally. Excessive production of reactive oxygen species (ROS) is detrimental to cardiomyocytes (CMs), triggering inflammation, inducing cell death, disrupting calcium homeostasis, and leading to arrhythmia. Thus, ROS is considered a common pathological factor in CVDs. Although the efficacy of antioxidants targeting ROS is currently limited, nanotechnology offers opportunities to develop antioxidants with improved selectivity and bioavailability, which can effectively prevent or treat oxidative stress-related CVDs. Cerium oxide nanozymes (CeONZs) can efficiently scavenge excessive ROS by mimicking the activity of endogenous antioxidant enzymes. However, their nanosafety and efficacy in human CMs remain unclear, posing a critical issue to be addressed before clinical applications. Due to the scarcity of primary human CMs, human pluripotent stem cells (hPSCs) and their derived cardiomyocytes (hPSC-CMs) provide a valuable source for modeling CVDs and their therapeutic interventions. This chapter presents a preparation method for CeONZs and outlines the assessment of their biosafety and antioxidant efficacy in hPSC-CMs.

Cardiac preservation using ex vivo organ perfusion: new therapies for the treatment of heart failure by harnessing the power of growth factors using BMP mimetics like THR-184

As heart transplantation continues to be the gold standard therapy for end-stage heart failure, the imbalance between the supply of hearts, and the demand for them, continues to get worse. In the US alone, with less than 4,000 hearts suitable for transplant and over 100,000 potential recipients, this therapy is only available to a very few. The use of hearts Donated after Circulatory Death (DCD) and Donation after Brain Death (DBD) using ex vivo machine perfusion (EVMP) is a promising approach that has already increased the availability of suitable organs for heart transplantation. EVMP offers the promise of enabling the expansion of the overall number of heart transplants and lower rates of early graft dysfunction. These are realized through (1) safe extension of the time between procurement and transplantation and (2) ex vivo assessment of preserved hearts. Notably, ex vivo perfusion has facilitated the donation of DCD hearts and improved the success of transplantation. Nevertheless, DCD hearts suffer from serious preharvest ischemia/reperfusion injury (IRI). Despite these developments, only 40% of hearts offered for transplantation can be utilized. These devices do offer an opportunity to evaluate donor hearts for transplantation, resuscitate organs previously deemed unsuitable for transplantation, and provide a platform for the development of novel therapeutics to limit cardiac injury. Bone Morphogenetic Protein (BMP) signaling is a new target which holds the potential for ameliorating myocardial IRI. Recent studies have demonstrated that BMP signaling has a significant role in blocking the deleterious effects of injury to the heart. We have designed novel small peptide BMP mimetics that act via activin receptor-like kinase (ALK3), a type I BMP receptor. They are capable of (1) inhibiting inflammation and apoptosis, (2) blocking/reversing the epithelial-mesenchymal transition (EMT) and fibrosis, and (3) promoting tissue regeneration. In this review, we explore the promise that novel therapeutics, including these BMP mimetics, offer for the protection of hearts against myocardial injury during ex vivo transportation for cardiac transplantation. This protection represents a significant advance and a promising ex vivo therapeutic approach to expanding the donor pool by increasing the number of transplantable hearts.

Quantitative histologic assessment of atrial fibrillation-associated fibrosis in animal models: A systematic review

Atrial fibrillation (AF) is the most common sustained arrhythmia, and cardiac fibrosis is a major component in driving its progressive nature. Quantitative histologic assessment of fibrosis in animal models is crucial for understanding AF, but current published studies present various methodologies that limit comparison. This systematic review examines 195 AF studies across multiple animal models (mice, rats, goats, dogs, pigs, and horses) to summarize (1) quantified fibrosis results and (2) methodologies for histologic fibrosis assessment; and (3) evaluate antifibrotic therapies used in these studies. The fibrosis quantified across the studies ranged from 0.34%-60.2% depending on the animal, intervention model, and quantification method. The findings underscore the need for a standardized fibrosis quantification protocol in AF research, enabling comparison across studies and offering greater insight into potential pharmacologic interventions.

The role and mechanism of TXNDC5 in cardio-oncology: Killing two birds with one stone?

Cardio-oncology has emerged as a new translational and clinical field owing to the growing repertory of cancer therapy. To date, there is a lack of effective pharmacological therapy to target cardiotoxicity. Cardio-oncology, which began by investigating the negative effects of cancer medicines on cardiovascular system, has since grown to include research into the similarities between cardiovascular disease (CVD) and cancer. Thioredoxin domain-containing protein 5 (TXNDC5) belongs to the protein disulfide isomerase (PDI) family. Many diseases, including CVD and cancer, improperly express TXNDC5. This review provides a comprehensive analysis of the expression patterns of TXNDC5 in diseases. It outlines the processes via which TXNDC5 contributes to the advancement of malignant diseases such as CVD and cancer. Additionally, it summarizes prospective therapeutic approaches that can be used to target TXNDC5 for the treatment of these diseases. This will offer novel perspectives for enhancing anticancer therapy and advancing cardio-oncology research and drug development.

The role of fibromodulin in myocardial fibrosis in a diabetic cardiomyopathy rat model

Diabetic cardiomyopathy (DCM) is pathologically characterized by excessive deposition of extracellular matrix proteins, leading to myocardial fibrosis. Fibromodulin (Fmod) plays a crucial role in the pathogenesis of fibrotic diseases. However, the role and mechanism of Fmod in DCM-related myocardial fibrosis remain unclear. In the present study, we established a DCM rat model and an in vitro model of rat primary cardiac fibroblasts (RPCFs) exposed to high glucose. We assessed mRNA and protein expression levels of Col1a1, Col3a1, α-SMA and Fmod in both models. Fmod-overexpressing (ov-Fmod) and Fmod-knockdown (si-Fmod) rat cardiac fibroblasts (RCFs) were generated. Subsequently, whole RNA sequencing was conducted on ov-Fmod RCFs. The gene Col15a1 was evaluated in the DCM rat and all cell models. The correlation between plasma levels of Fmod and Col15a1 in DCM rat models was assessed. Transcription and protein levels of Fmod, Col1a1, Col3a1 and α-SMA were significantly elevated in DCM rat hearts and RPCFs. In ov-Fmod RCFs, fibrosis markers were similarly increased, except for Col3a1, which decreased. The Col1a1/Col3a1 ratio was elevated. Conversely, knocking down Fmod yielded opposite results. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses indicated that Fmod participates in multiple fibrosis-related pathways, affecting Col15a1. Expression of Col15a1 was significantly decreased in all models, compared to controls, except in si-Fmod RCFs. Importantly, Col15a1 and Fmod in plasma exhibited an inverse relationship in DCM. In summary, Fmod is implicated in DCM, with Fmod overexpression downregulating Col15a1 and increasing the Col1a1/Col3a1 ratio. This mechanism may influence diastolic heart failure in DCM by modulating myocardial stiffness and elasticity.

Lnc PVT1 facilitates TGF-β1-induced human cardiac fibroblast activation in vitro and ISO-induced myocardial fibrosis in vivo through regulating MYC

Cardiac fibrosis is a commonly seen pathophysiological process in various cardiovascular disorders, such as coronary heart disorder, hypertension, and cardiomyopathy. Cardiac fibroblast trans-differentiation into myofibroblasts (MFs) is a key link in myocardial fibrosis. LncRNA PVT1 participates in fibrotic diseases in multiple organs; however, its role and mechanism in cardiac fibrosis remain largely unknown. Human cardiac fibroblasts (HCFs) were stimulated with TGF-β1 to induce myofibroblast; Immunofluorescent staining, Immunoblotting, and fluorescence in situ hybridization were used to detect the myofibroblasts phenotypes and lnc PVT1 expression. Cell biological phenotypes induced by lnc PVT1 knockdown or overexpression were detected by CCK-8, flow cytometry, and Immunoblotting. A mouse model of myocardial fibrosis was induced using isoproterenol (ISO), and the cardiac functions were examined by echocardiography measurements, cardiac tissues by H&E, and Masson trichrome staining. In this study, TGF-β1 induced HCF transformation into myofibroblasts, as manifested as significantly increased levels of α-SMA, vimentin, collagen I, and collagen III; the expression level of lnc PVT1 expression showed to be significantly increased by TGF-β1 stimulation. The protein levels of TGF-β1, TGFBR1, and TGFBR2 were also decreased by lnc PVT1 knockdown. Under TGF-β1 stimulation, lnc PVT1 knockdown decreased FN1, α-SMA, collagen I, and collagen III protein contents, inhibited HCF cell viability and enhanced cell apoptosis, and inhibited Smad2/3 phosphorylation. Lnc PVT1 positively regulated MYC expression with or without TGF-β1 stimulation; MYC overexpression in TGF-β1-stimulated HCFs significantly attenuated the effects of lnc PVT1 knockdown on HCF proliferation and trans-differentiation to MFs. In the ISO-induced myocardial fibrosis model, lnc PVT1 knockdown partially reduced fibrotic area, improved cardiac functions, and decreased the levels of fibrotic markers. In addition, lnc PVT1 knockdown decreased MYC and CDK4 levels but increased E-cadherin in mice heart tissues. lnc PVT1 is up-regulated in cardiac fibrosis and TGF-β1-stimulated HCFs. Lnc PVT1 knockdown partially ameliorates TGF-β1-induced HCF activation and trans-differentiation into MFs in vitro and ISO-induced myocardial fibrosis in vivo, potentially through interacting with MYC and up-regulating MYC.

Analysis of Biomarker Levels in Nasopharyngeal Swabs, Serum, and Saliva Across Different Health Conditions

BACKGROUND

Coronavirus disease 2019 (COVID-19) is associated with a wide variety of clinical manifestations.

AIM

This study aims to evaluate the levels of angiotensin-converting enzyme 2 (ACE2), metalloprotease 17 (ADAM17), Interleukin-17A (IL-17A), transmembrane serine protease 2 (TMPRSS2), apelin (AP), and vitamin D (VD) biomarkers in nasopharyngeal swab (NPS), serum, and saliva, as well as the change in their values depending on the health status of individuals.

MATERIAL AND METHODS

The analysis was performed by using enzyme-linked immunosorbent assay (ELISA) methods.

RESULTS

Comparing the levels of the investigated markers in saliva, we found significantly elevated ACE2 values in vaccinated patients, followed by those with severe COVID-19, compared to healthy, previously infected, and mild COVID-19 groups. For TMPRSS2, IL-17A, ADAM-17, and AP, values were significantly higher in all non-healthy groups (previously infected, mild, and severe COVID-19) compared to healthy individuals. Serum levels of VD were consistently low across all five studied groups, suggesting values below normal ranges. Analysis of marker data in saliva, NPS, and serum revealed a positive correlation between NPS and serum and saliva and serum, as well as between saliva and NPS for all studied markers.

CONCLUSIONS

In summary, monitoring changes in biomarkers present in Saliva holds promise as a predictive tool for various diseases. This approach enables the early implementation of preventive measures and protective strategies, potentially improving overall health outcomes.

Viscoelastic Mechanics: From Pathology and Cell Fate to Tissue Regeneration Biomaterial Development

Viscoelasticity is the mechanical feature of living tissues and the cellular extracellular matrix (ECM) and has been recognized as an essential biophysical cue in cell function and fate regulation, tissue development and homeostasis maintenance, and disease progression. These findings provide new insights for the development of biomaterials with comparable viscoelastic properties as native ECMs and the tissue matrix, displaying promising applications in regeneration medicine. In this review, the relationship between matrix viscoelasticity and tissue functions (e.g., development and regeneration) in physiological conditions and disease progression (e.g., aging, degenerative, fibrosis, and tumor) in pathological conditions will be especially highlighted to figure out the potential therapeutic target for disease treatment and inspiration for tissue regeneration related biomaterial development. Furthermore, findings and an understanding of the cell response to ECM viscoelasticity and the mechanism behind it are comprehensively summarized to provide a pathophysiological basis for viscoelastic biomaterials design. The advances of viscoelastic biomaterials on defect tissue repair are also reviewed, suggesting the significance of the native matrix matchable microenvironment on tissue regeneration. Although challenging, tunable viscoelastic biomaterials that match the mechanical properties of native tissues and ECMs show great promise. They could promote tissue regeneration, treat degenerative diseases, and support the development of organoids and artificial organs.

Upregulated LIMD1 alleviates pressure overload-induced cardiac hypertrophy via inhibits YAP1/AKT/GSK3β signaling

OBJECTIVES

Pathological cardiac hypertrophy plays a significant role in the development and progression of heart failure (HF). LIM Domain Containing 1 (LIMD1) serves as a crucial regulatory factor in protein-protein interactions during cellular signal transduction. This study aims to investigate the specific roles and mechanisms of LIMD1 in pathological cardiac remodeling.

METHODS

We employed an adeno-associated virus 9 (AAV9) system to overexpress LIMD1 in the hearts through tail vein injection. C57BL/6 mice underwent transverse aortic constriction (TAC) for four weeks. Cardiac function was assessed using echocardiography, while cardiac remodeling was evaluated through histopathology and molecular techniques.

RESULTS

Our findings demonstrated elevated levels of LIMD1 in murine hearts subjected to TAC treatment and H9c2 cells challenged with angiotensin II (Ang II). Compared with wild-type (WT) mice, those injected with AAV-9-LIMD1 exhibited significantly reduced TAC-induced cardiac dysfunction, hypertrophy, and fibrosis. Mechanistically, both in vitro and in vivo experiments suggested that the beneficial effects of LIMD1 might be associated with the inhibition of the YAP1/AKT/GSK3β signaling pathway.

CONCLUSION

In summary, this study is the first to demonstrate the protective effects of LIMD1 against TAC-induced pathological cardiac remodeling. These effects are attributed to the inhibition of the YAP1/AKT/GSK3β signaling pathway.

Dan-shen Yin attenuates myocardial fibrosis after myocardial infarction in rats: Molecular mechanism insights by integrated transcriptomics and network pharmacology analysis and experimental validation

ETHNOPHARMACOLOGICAL RELEVANCE

Dan-shen Yin (DSY) originated from the "Shi Fang Ge Kuo" is a Chinese formula composed of three medicines: Salvia miltiorrhiza (Dan-shen), Santalum album L. (Tan-xiang) and Amomum villosum Lour. (Sha-ren). It has many years of clinical experience in the prevention of myocardial fibrosis (MF). However, the specific mechanism of DSY in prevent MF is not clear.

AIM OF THE STUDY

This study aimed to assess the efficacy of DSY in the prevention of MF and reveal its underlying mechanism in a rat model of MF after myocardial infarction (MI) induced by ligation of the left anterior descending branch (LAD) of the coronary artery.

MATERIALS AND METHODS

The blood-entry components of DSY were analyzed by UHPLC-Q-TOF-MS/MS. LAD-ligated rats were used to assess the efficacy of DSY in the prevention of MF. Network pharmacology and transcriptomics analysis were used to predict possible target signaling pathways of DSY in MF. Echocardiography, immunohistochemistry and ELISA methods were used to evaluate the cardiac functions and biochemical changes of the rats. The mRNA expressions of target genes were measured by RT-qPCR. The proteins expressions, including Collagen I, Collagen III, α-smooth muscle actin (α-SMA), matrix metallopeptidase 2 (MMP 2), matrix metallopeptidase 9 (MMP 9), transforming growth factor-β (TGF-β), protein kinase B (AKT), phospho-AKT, extracellular regulated protein kinases (ERK), phospho-ERK, c-Jun N-terminal kinase (JNK), phospho-JNK, mothers against decapentaplegic protein (Smad3), and phospho-Smad3 were detected and quantified by Western Blot.

RESULTS

UHPLC-Q-TOF-MS/MS analysis disclosed that 20 components within DSY could be absorbed into blood of rats. DSY improved myocardial injury in the myocardial tissue of LAD-ligated rats, as evidenced by the elevation of left ventricular ejection fraction and left ventricular fractional shortening, and the decrease of the serum CK-MB and LDH levels. Network pharmacology and transcriptomics predicted that DSY could interfere biological processes, such as extracellular matrix organization, focal adhesion and ECM-receptor interaction, and modulate TGF-β mediated signaling pathways, including PI3K/AKT, MAPK, and Smad3. Further study confirmed that DSY reduced MF, accompanied by reduced TGF-β, Collagen I, Collagen III, α-SMA, MMP 2 and MMP 9. Moreover, DSY repressed the phosphorylation of AKT, MAPKs and Smad3. In addition, DSY reduced inflammation and suppressed the mRNA expressions of IL-1β, IL-6, TNF-α, COX2 and iNOS in MF rats.

CONCLUSIONS

Our study demonstrated that DSY prevented MF in vivo, the action of which was probably via reducing extracellular matrix organization, focal adhesion ECM-receptor interaction and inflammation by regulating TGF-β mediated PI3K/AKT, MAPK and Smad signaling pathways.

Comparative Efficacy of β-Carotene and Losartan Against Isoproterenol-Induced Cardiac Fibrosis: An Experimental and Computational Studies

OBJECTIVE

β-carotene, a vitamin A precursor is reported to inhibit molecular pathways cardinal to pathogenesis of fibrotic tissue alterations and in this study, the effectiveness of 14 days oral administration of β-carotene (10, 20, and 40 mg/kg/day) in the cardiac fibrosis (CF) in rats was studied and explored the mechanisms through network pharmacology.

METHODS

CF was induced by isoproterenol (ISO) 6 mg/kg/SC from day 1 to day 7. Losartan (LOS) 10 mg/kg/day/p.o. served as the standard. Both β-carotene and LOS were administered from day 1 to 14. On the 15th day, ECG and blood pressure (systolic, diastolic and mean) were recorded in the anesthetized rats followed by their euthanasia. The extent of cardiac fibrosis in the isolated hearts was determined using heart coefficient, tissue levels of hydroxyproline, histological examination. The oxidative stress in cardiac tissue was estimated, as GSH, SOD, catalase, MDA and NO. β-carotene targeted proteins pathway, process, and functional enrichment analysis were explored through network pharmacology.

RESULTS

β-carotene dose-dependently mitigated the biochemical and histological changes induced by ISO in heart tissues. In ECG, it restored ST height, QT, and QRS intervals. Additionally, it normalized systolic, diastolic, and mean arterial pressures. The reduction in heart coefficient suggests β-carotene's potential to inhibit collagen deposition in heart tissue. β-carotene normalized oxidative stress markers, and hydroxyproline levels. All other biochemical parameters were restored to normal levels with β-carotene treatment. β-carotene 40 mg/kg dose showed comparable effect to that of LOS 10 mg/kg. β-carotene modulated IL-17, TNF, NF-kappa B, HIF-1, Sphingolipid, Relaxin, Adipocytokine, cAMP, Toll-like receptor, MAPK, PI3K-Akt, cGMP-PKG, VEGF, Ras, and PPAR signaling pathways.

CONCLUSIONS

β-carotene dose-dependently protects against ISO-induced CF in rats, with 40 mg/kg as an effective antifibrotic dose.

Engineered Strategies to Interfere with Macrophage Fate in Myocardial Infarction

Myocardial infarction (MI), a severe cardiovascular condition, is typically triggered by coronary artery disease, resulting in ischemic damage and the subsequent necrosis of the myocardium. Macrophages, known for their remarkable plasticity, are capable of exhibiting a range of phenotypes and functions as they react to diverse stimuli within their local microenvironment. In recent years, there has been an increasing number of studies on the regulation of macrophage behavior based on tissue engineering strategies, and its regulatory mechanisms deserve further investigation. This review first summarizes the effects of key regulatory factors of engineered biomaterials (including bioactive molecules, conductivity, and some microenvironmental factors) on macrophage behavior, then explores specific methods for inducing macrophage behavior through tissue engineering materials to promote myocardial repair, and summarizes the role of macrophage-host cell crosstalk in regulating inflammation, vascularization, and tissue remodeling. Finally, we propose some future challenges in regulating macrophage-material interactions and tailoring personalized biomaterials to guide macrophage phenotypes.

The Chinese Herbal Medicine Li Qi Huo Xue Di Wan Ameliorates Ischemia or Hypoxia-Induced Cardiac Injury and Remodeling in the Heart Through a Mechanism Involving Reduction of Necroptosis

Li Qi Huo Xue Di Wan (LQHXDW), a Chinese herbal medicine, is commonly used to treat symptoms such as palpitations, chest tightness, chest pain, and shortness of breath. However, its potential to reduce ischemia or hypoxia-induced cardiac injury and remodeling, along with the precise mechanisms involved, remains unclear. This study aims to investigate the effects of LQHXDW on cardiac injury and remodeling induced by ischemia or hypoxia, both in vivo and in vitro, and to elucidate the underlying mechanisms. The mouse heart was subjected to ischemia for 14 days, showing evident myocardial injury and notable cardiac remodeling, accompanied by a reduction in cardiac function; these phenomena were reversed in the presence of LQHXDW. In the cultured cardiomyocyte exposed to hypoxia, incubation with LQHXDW increased the cell viability and reduced lactate dehydrogenase release. Mechanistically, LQHXDW exerted inhibitory effect on the phosphorylation levels of RIPK1, RIPK3, and MLKL as well as oxidative stress in the mice hearts suffered ischemia and the cultured cardiomyocytes exposed to hypoxia. Using the methods of ultra-high performance liquid chromatography-quadrupole time-of-flight-mass spectrometry, network pharmacology, and cellular thermal shift assay, phenethyl caffeate and isoliquiritigenin were identified as the potential active compounds in LQHXDW that counteract necroptosis. Based on these observations, we conclude that LQHXDW protects the heart against ischemia or hypoxia-induced cardiac injury and remodeling through suppression of the RIPK1/RIPK3/MLKL pathway-dependent necroptosis and oxidative stress.

Chronic ethanol exposure induces cardiac fibroblast transdifferentiation via ceramide accumulation and oxidative stress

AIMS

Excessive alcohol consumption is associated with cardiac dysfunction and the development of myocardial fibrosis. In this study, we aimed to investigate the direct impacts of ethanol on myocardial fibroblasts and elucidate the underlying mechanism responsible for chronic ethanol-induced myocardial fibrosis.

METHODS

Rat primary cardiac fibroblasts exposed to ethanol for 24 h and C57BL/6J mice fed on Lieber-DeCarli diet to establish an ethanol intoxication model in vitro and in vivo, respectively. Histological analyses, molecular biology techniques, and analytical chemistry methods were then conducted.

RESULTS AND CONCLUSION

In vivo and vitro experiments revealed that chronic ethanol exposure induced increased myocardial fibrosis and augmented the transdifferentiation of myocardial fibroblasts. Simultaneously, it elicited an upregulation in the production of long-chain and very-long-chain ceramides in cardiac fibroblasts. The excessive accumulation of ceramide leads to elevated levels of intracellular oxidative stress, culminating in the activation of TGF-β-SMAD3 signaling and the development of fibrosis. Intervention of these pathways with pharmacological inhibitors in vitro or in vivo inhibited fibrosis. In conclusion, ethanol increased ceramides and reactive oxygen species (ROS) in cardiac fibroblasts, resulting in the activation of TGF-β-SMAD3 signaling, transdifferentiation of fibroblasts, and myocardial fibrosis.

G protein regulation by RGS proteins in the pathophysiology of dilated cardiomyopathy

Regulators of G protein signaling (RGS) proteins fine-tune signaling via heterotrimeric G proteins to maintain physiologic homeostasis in various organ systems of the human body including the brain, kidney, heart, and vasculature. Impaired regulation of G protein signaling by RGS proteins is implicated in the pathogenesis of several human diseases including various forms of cardiomyopathy such as hypertrophic cardiomyopathy and dilated cardiomyopathy (DCM). Both genetic and nongenetic changes that impinge on G protein signaling in cardiomyocytes are implicated in the etiology of DCM, and there is accumulating evidence that such genetic and nongenetic changes affecting G protein signaling in cell types other than cardiomyocytes could serve as a DCM trigger in humans. This review discusses and highlights mammalian RGS proteins and their roles in cardiac physiology and disease, with a specific focus on the current understanding of the etiology of DCM and the pathogenic roles of RGS proteins that are prominently expressed in the cardiovascular system. Growing evidence suggests that defects in G protein regulation by RGS proteins in the cardiovascular system likely contribute to cardiomyocyte structural damage and decreased contractile function that hallmark DCM. Further studies that enhance the understanding of the dynamics of G protein regulation by RGS proteins in several cell types in the myocardium and the vasculature are critical to gaining more insight into the etiology of DCM and heart failure, and to the identification of novel therapeutic targets.

The role of fibroblast in chronic rhinosinusitis with nasal polyps: a key player in the inflammatory process

INTRODUCTION

Fibroblasts are the primary supporting cells in connective tissue and have long been thought to contribute to chronic rhinosinusitis with nasal polyps (CRSwNP) by producing extracellular matrix (ECM), leading to fibrosis and tissue remodeling. However, recent studies have highlighted the critical role of nasal polyp-derived fibroblasts (NPDFs) in triggering and intensifying the inflammatory response in CRSwNP.

AREAS COVERED

This review undertook a comprehensive literature search across the PubMed database, Web of Science since 2000, offering an in-depth summary of the pivotal role of NPDFs in tissue remodeling and inflammatory responses in CRSwNP. Additionally, single-cell RNA sequencing data provides a deeper exploration of the heterogeneity and functional mechanisms of fibroblasts in CRSwNP. Consequently, these insights point to fibroblasts as promising therapeutic targets for effectively treating CRSwNP.

EXPERT OPINION

Current data underscore the essential role of fibroblasts in the pathogenesis of CRSwNP. Fully elucidating the specific mechanisms by which fibroblasts contribute to the disease process is crucial for developing targeted therapies. Furthermore, advancements in single-cell RNA sequencing pave the way for selectively targeting and depleting pathological fibroblast subpopulations. Despite these advancements, the clinical development of fibroblast-targeted therapies in CRSwNP remains challenging.

Fibulin 1 and 2 Levels in Patients with Heart Failure: Comparison of Different Heart Failure Stages and Exploring the Temporal Changes During Acute Exacerbation

Background

Fibulin 1 and Fibulin 2 are members of the extracellular matrix (ECM) glycoprotein family. ECMs drive prognosis through remodeling, a key step in the pathogenesis of heart failure (HF). We aimed to compare Fibulin 1 and 2 levels in different stages of HF and to investigate their relationship with other prognostic factors of HF.

Methods

Patients with HF were divided into two groups according to left ventricular ejection fraction (LVEF): reduced and non-reduced LVEF. The control and patient groups consisted of individuals with Stages A and B HF, Stages C and D HF, respectively. Fibulin levels were measured at different stages of HF and in the control group. Additionally, Fibulin levels were measured at admission, discharge, and in the first month in patients who were hospitalized due to decompensated HF.

Results

Serum Fibulin 1 and N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels were significantly higher in the patient group than in the control group. Serum Fibulin 2 levels were similar between the groups. Although serum Fibulin 2 levels were similar at repeated measurements, serum Fibulin 1 and NT-proBNP levels significantly decreased at discharge and remained similar at 1 month compared with admission. There was a significant positive correlation between Fibulin 1 and NT-proBNP levels and a significant negative correlation between Fibulin 1 levels and LVEF. Fibulin 2 levels were not correlated with LVEF and NT-proBNP.

Conclusions

Our study demonstrated that serum Fibulin 1 levels differ among different HF stages and have a similar temporal change as observed for NT-proBNP levels. A similar association was not observed for Fibulin 2 in our study.

Involvement of TGF-β, mTOR, and inflammatory mediators in aging alterations during myxomatous mitral valve disease in a canine model

Inflammaging, a state of chronic low-grade inflammation associated with aging, has been linked to the development and progression of various disorders. Cellular senescence, a state of irreversible growth arrest, is another characteristic of aging that contributes to the pathogenesis of cardiovascular pathology. Senescent cells accumulate in tissues over time and secrete many inflammatory mediators, further exacerbating the inflammatory environment. This senescence-associated secretory phenotype can promote tissue dysfunction and remodeling, ultimately leading to the development of age-related cardiovascular pathologies, such as mitral valve myxomatous degeneration. The species-specific form of canine myxomatous mitral valve disease (MMVD) provides a unique opportunity to investigate the early causes of induction of ECM remodeling in mitral valve leaflets in the human form of MMVD. Studies have shown that in both humans and dogs, the microenvironment of the altered leaflets is inflammatory. More recently, the focus has been on the mechanisms leading to the transformation of resting VICs (qVICs) to myofibroblast-like VICs (aVICs). Cells affected by stress fall into a state of cell cycle arrest and become senescent cells. aVICs, under the influence of TGF-β signaling pathways and the mTOR complex, enhance ECM alteration and accumulation of systemic inflammation. This review aims to create a fresh new view of the complex interaction between aging, inflammation, immunosenescence, and MMVD in a canine model, as the domestic dog is a promising model of human aging and age-related diseases.

Esaxerenone Attenuates Cardiac Hypertrophy in a Pressure Overload Model in Mice

Esaxerenone, a non-steroidal mineralocorticoid receptor (MR) blocker, exhibits high selectivity for MR. While clinically used as an anti-hypertensive drug, its impact on cardiac remodeling remains poorly understood. This study investigated the effect of esaxerenone on pressure overload-induced cardiac hypertrophy in mice.Eight-week-old C57BL/6 mice underwent either transverse aortic constriction (TAC) or sham surgery. Animals were divided into 2 groups: 0.003% (3.0 mg/kg) Esaxerenone-fed (EX) and normal-fed (CNT) groups (n = 64, Sham/CNT = 12, Sham/EX = 13, TAC/CNT = 18, TAC/EX = 21). Cardiac gene expressions were analyzed using quantitative real-time PCR.Food intake and body weight variations showed no significant differences between CNT and EX groups during the 2-week experimental period. The mortality rate from 24 hours after TAC surgery to the end of the experiment was 30.8% in the CNT group, however, all mice survived following TAC surgery in EX group. CNT group showed a remarkable increase in heart weight/tibial length ratio 2 weeks after TAC compared with the Sham group. The EX group demonstrated a significant decrease in HW/TL following TAC surgery (-23.4%, P = 0.041). Masson's trichrome staining revealed that the TAC/CNT group had a significantly higher proportion of fibrotic area than the Sham/CNT group. However, the TAC/EX group had a slightly lower proportion of fibrotic area than the TAC/CNT group. In cardiac gene expression analysis, ANP and Collagen 3a1 were upregulated in the TAC group but were significantly reduced following treatment with esaxerenone.Esaxerenone attenuates cardiac hypertrophy and hypertrophy-related gene expression, resulting in improved survival in a pressure overload model in mice.

Targeting Fibrosis: From Molecular Mechanisms to Advanced Therapies

As the final stage of disease-related tissue injury and repair, fibrosis is characterized by excessive accumulation of the extracellular matrix. Unrestricted accumulation of stromal cells and matrix during fibrosis impairs the structure and function of organs, ultimately leading to organ failure. The major etiology of fibrosis is an injury caused by genetic heterogeneity, trauma, virus infection, alcohol, mechanical stimuli, and drug. Persistent abnormal activation of "quiescent" fibroblasts that interact with or do not interact with the immune system via complicated signaling cascades, in which parenchymal cells are also triggered, is identified as the main mechanism involved in the initiation and progression of fibrosis. Although the mechanisms of fibrosis are still largely unknown, multiple therapeutic strategies targeting identified molecular mechanisms have greatly attenuated fibrotic lesions in clinical trials. In this review, the organ-specific molecular mechanisms of fibrosis is systematically summarized, including cardiac fibrosis, hepatic fibrosis, renal fibrosis, and pulmonary fibrosis. Some important signaling pathways associated with fibrosis are also introduced. Finally, the current antifibrotic strategies based on therapeutic targets and clinical trials are discussed. A comprehensive interpretation of the current mechanisms and therapeutic strategies targeting fibrosis will provide the fundamental theoretical basis not only for fibrosis but also for the development of antifibrotic therapies.

Impact of Type 2 Diabetes Mellitus on Left Atrioventricular Coupling and Left Atrial Deformation in Patients with Essential Hypertension: An MRI Feature Tracking Study

BACKGROUND

Hypertension (HTN) and type 2 diabetes mellitus (T2DM) are both associated with left ventricular (LV) and left atrial (LA) structural and functional abnormalities; however, the relationship between the left atrium and ventricle in this population is unclear.

PURPOSE

To identify differences between hypertensive patients with and without T2DM as the basis for further investigation the atrioventricular coupling relationship.

STUDY TYPE

Cross-sectional, retrospective study.

POPULATION

89 hypertensive patients without T2DM [HTN (T2DM-)] (age: 58.4 +/- 11.9 years, 48 male), 62 hypertensive patients with T2DM [HTN (T2DM+)] (age: 58.5 +/- 9.1 years, 32 male) and 70 matched controls (age: 55.0 +/- 9.6 years, 37 male).

FIELD STRENGTH/SEQUENCE

2D balanced steady-state free precession cine sequence at 3.0 T.

ASSESSMENT

LA reservoir, conduit, and booster strain (εs, εe, and εa) and strain rate (SRs, SRe, and SRa), LV radial, circumferential and longitudinal peak strain (PS) and peak systolic strain rate and peak diastolic strain rate (PSSR and PDSR) were derived from LA and LV cine images and compared between groups.

STATISTICAL TESTS

Chi-square or Fisher's exact test, one-way analysis of variance, analysis of covariance, Pearson's correlation, multivariable linear regression analysis, and intraclass correlation coefficient. A P value <0.05 was considered significant.

RESULTS

Compared with controls, εs, εe, SRe and PS-longitudinal, PDSR-radial, and PDSR-longitudinal were significantly lower in HTN (T2DM-) group, and they were even lower in HTN (T2DM+) group than in both controls and HTN (T2DM-) group. SRs, εa, SRa, as well as PS-radial, PS-circumferential, PSSR-radial, and PSSR-circumferential were significantly lower in HTN (T2DM+) compared with controls. Multivariable regression analyses demonstrated that: T2DM and PS-circumferential and PS-longitudinal (β = -4.026, -0.486, and -0.670, respectively) were significantly associated with εs; T2DM and PDSR-radial and PDSR-circumferential were significantly associated with εe (β = -3.406, -3.352, and -6.290, respectively); T2DM and PDSR-radial were significantly associated with SRe (β = 0.371 and 0.270, respectively); T2DM and PDSR-longitudinal were significantly associated with εa (β = -1.831 and 5.215, respectively); and PDSR-longitudinal was significantly associated with SRa (β = 1.07).

DATA CONCLUSION

In hypertensive patients, there was severer LA dysfunction in those with coexisting T2DM, which may be associated with more severe LV dysfunction and suggests adverse atrioventricular coupling.

EVIDENCE LEVEL

3.

TECHNICAL EFFICACY

Stage 3.

Emerging Role of Macrophage-Fibroblast Interactions in Cardiac Homeostasis and Remodeling

As major noncardiomyocyte components in cardiac tissues, macrophages and fibroblasts play crucial roles in maintaining cardiac homeostasis, orchestrating reparative responses after cardiac injuries, facilitating adaptive cardiac remodeling, and contributing to adverse cardiac remodeling, owing to their inherent heterogeneity and plasticity. Recent advances in research methods have yielded novel insights into the intricate interactions between macrophages and fibroblasts in the cardiac context. This review aims to comprehensively examine the molecular mechanisms governing macrophage-fibroblast interactions in cardiac homeostasis and remodeling, emphasize recent advancements in the field, and offer an evaluation from a translational standpoint.

Novel Therapeutic Strategies Targeting Fibroblasts to Improve Heart Disease

Cardiac fibrosis represents the terminal pathological manifestation of various heart diseases, with the formation of fibroblasts playing a pivotal role in this process. Consequently, targeting the formation and function of fibroblasts holds significant potential for improving outcomes in heart disease. Recent research reveals the considerable potential of fibroblasts in ameliorating cardiac conditions, demonstrating different functional characteristics at various time points and spatial locations. Therefore, precise modulation of fibroblast activity may offer an effective approach for treating cardiac fibrosis and achieving targeted therapeutic outcomes. In this review, we focus on the fate and inhibition of fibroblasts, analyze their dynamic changes in cardiac diseases, and propose a framework for identifying markers of fibroblast activation mechanisms and selecting optimal time windows for therapeutic intervention. By synthesizing research findings in these areas, we aim to provide new strategies and directions for the precise treatment of fibroblasts in cardiac diseases.

Modeling the contribution of cardiac fibroblasts in dilated cardiomyopathy using induced pluripotent stem cells

Fibrosis is implicated in nearly all forms of cardiomyopathy and significantly influences disease severity and outcomes. The primary cell responsible for fibrosis is the cardiac fibroblast, which remains understudied relative to cardiomyocytes in the context of cardiomyopathy. The development of induced pluripotent stem cell-derived cardiac fibroblasts (iPSC-CFs) allows for the modeling of patient-specific disease characteristics and provides a scalable source of fibroblasts. iPSC-CFs are invaluable for understanding molecular pathways that affect disease progression and outcomes. This review explores various aspects of cardiomyopathy, with a focus on dilated cardiomyopathy, that can be modeled using iPSC-CFs and their application in drug discovery, given the current lack of approved therapies for cardiac fibrosis. We examine how iPSC-CFs can be utilized to study heart development, fibroblast heterogeneity, and activation, with the ultimate goal of developing better therapies for patients with cardiomyopathies. SIGNIFICANCE STATEMENT: We explore how induced pluripotent stem cell-derived cardiac fibroblasts (iPSC-CFs) are used to study the fibrotic component of dilated cardiomyopathy. Most research has focused on cardiomyocytes, but iPSC-CFs serve as a valuable tool to elucidate molecular pathways leading to fibrosis and paracrine interactions with cardiomyocytes. Gaining insights into these events could aid in the development of new therapies and enable the use of patient-derived iPSC-CFs for precision medicine, ultimately improving patient outcomes.

Heart remodelling affects ECG in rat DOCA/salt model

Myocardial remodelling involves structural and functional changes in the heart, potentially leading to heart failure. The deoxycorticosterone acetate (DOCA)/salt model is a widely used experimental approach to study hypertension-induced cardiac remodelling. It allows to investigate the mechanisms underlying myocardial fibrosis and hypertrophy, which are key contributors to impaired cardiac function. In this study, myocardial remodelling in rat deoxycorticosterone acetate/salt model was examined over a three-week period. The experiment involved 11 male Sprague-Dawley rats, divided into two groups: fibrosis (n=6) and control (n=5). Myocardial remodelling was induced in the fibrosis group through unilateral nephrectomy, deoxyco-rticosterone acetate administration, and increased salt intake. The results revealed significant structural changes, including increased left ventricular wall thickness, myocardial fractional volume, and development of myocardial fibrosis. Despite these changes, left ventricular ejection fraction was preserved and even increased. ECG analysis showed significant prolongation of the PR interval and widening of the QRS complex in the fibrosis group, indicating disrupted atrioventricular and ventricular conduction, likely due to fibrosis and hypertrophy. Correlation analysis suggested a potential relationship between QRS duration and myocardial hypertrophy, although no significant correlations were found among other ECG parameters and structural changes detected by MRI. The study highlights the advantage of the DOCA/salt model in exploring the impact of myocardial remodelling on electrophysiological properties. Notably, this study is among the first to show that early myocardial remodelling in this model is accompanied by distinct electrophysiological changes, suggesting that advanced methods combined with established animal models can open new opportunities for research in this field. Key words Myocardial fibrosis, Remodelling, Animal model, DOCA-salt, Magnetic resonance imaging.

Effects of Empagliflozin and Dapagliflozin in alleviating cardiac fibrosis through SIRT6-mediated oxidative stress reduction

Sodium-glucose co-transport protein 2 (SGLT2) inhibitors, a novel category of oral hypoglycemic agents, offer a promising outlook for individuals experiencing heart failure with reduced ejection fraction. Evidence is emerging that highlights their potential in alleviating myocardial fibrosis and oxidative stress. However, the precise mechanisms through which SGLT2 inhibitors influence myocardial fibrosis induced by angiotensin II (Ang II) or transforming growth factor-β1 (TGF-β1) are not fully understood. This study aims to explore the intricate mechanisms by which SGLT2 inhibitors ameliorate myocardial fibrosis, particularly focusing on the nuanced interplay within the SIRT6 signaling pathway. Primary cardiac fibroblasts were isolated from the hearts of 1-3-day-old neonatal KM mice, were stimulated with Ang II or TGF-β1 to establish an in vitro model of myocardial fibrosis. Treatment with 10 µM Empagliflozin (EMPA) and Dapagliflozin (DAPA) significantly curtailed the proliferation of cardiac fibroblasts, substantially reduced collagen expression induced by Ang II/TGF-β1, and mitigated the phenotypic transformation and oxidative stress response. SIRT6, which is closely associated with myocardial fibrosis, demonstrated that the suppression its expression attenuated the protective effects of EMPA and DAPA against myocardial fibrosis and oxidative stress. Our findings suggest that SGLT2 inhibitors markedly decrease the Ang II/TGF-β1-induced transformation of cardiac fibroblasts to a myofibroblast phenotype by upregulating SIRT6 protein expression, thereby inhibiting oxidative stress and ameliorating myocardial fibrosis.

Early Myocardial Strain Reduction and miR-122-5p Elevation Associated with Interstitial Fibrosis in Anthracycline-Induced Cardiotoxicity

Echocardiographic myocardial strain is crucial for early detection of anthracycline-induced cardiotoxicity, particularly in patients at moderate or high risk.

BACKGROUND/OBJECTIVES

This study investigates changes in global longitudinal strain (GLS) in breast cancer patients with low baseline risk for cardiotoxicity during cancer therapy. We also examined the relationship between echocardiographic strain, structural myocardial changes, and microRNA (miRNA) dysregulation associated with cancer treatment using an animal model.

METHODS

Echocardiography and blood tests were examined in 33 breast cancer patients with low baseline risk for cardiotoxicity during anthracycline treatment, with a follow-up at 12 months. Additionally, 16 Wistar rats received epirubicin (20 mg/kg over 4 weeks) to examine cardiac strain and structural changes. Moreover, circulating miRNA levels were assessed in patients' serum using microarray at the end of the treatment and further analyzed in peripheral blood from the animal model.

RESULTS

Pathological GLS values were observed in 27.27% of patients after four cycles, with 15.15% showing reduced left ventricular ejection fraction (LVEF) after 12 months. In the animal model, epirubicin-induced circumferential strain (CS) decrease correlates with myocardial fibrosis assessed histologically and by a significant increase in COL1 and TGFB2 expression. Furthermore, we found a significant decrease in aquaporin1 expression associated with the presence of vacuoles in treated rats. Furthermore, dysregulation in the expression of miRNAs was observed in patients with cardiotoxicity. Among them, hsa-miR-122-5p is increased in both patient and rat serum post-treatment.

CONCLUSIONS

A notable percentage of low-risk patients exhibited cardiac strain reduction due to cardiotoxicity. Epirubicin treatment caused structural heart changes in rats, highlighting miR-122-5p as a potential fibrosis marker that correlated with echocardiographic parameters.

Integration of Microarray Data and Single-Cell Sequencing Analysis to Explore Key Genes Associated with Macrophage Infiltration in Heart Failure

Background

Cardiac macrophages are a heterogeneous population with high plasticity and adaptability, and their mechanisms in heart failure (HF) remain poorly elucidated.

Methods

We used single-cell and bulk RNA sequencing data to reveal the heterogeneity of non-cardiomyocytes and assess the immunoreactivity of each subpopulation. Additionally, we employed four integrated machine learning algorithms to identify macrophage-related genes with diagnostic value, and in vivo validation was performed. To assess the immune infiltration characteristics in HF, we utilized the CIBERSORT and single sample gene set enrichment analysis (ssGSEA). An unsupervised consensus clustering algorithm was applied to identify the macrophage-related HF subtypes. Furthermore, the scMetabolism was employed to explore the specific metabolic patterns of the macrophage subtypes. Finally, CellChat was used to investigate cell-cell interactions among the identified subtypes.

Results

The immunoreactivity score of macrophages in the HF was higher than that in the other cell types. GSEA of macrophage clusters indicated a significant enrichment of leukocyte-mediated immune processes, antigen processing, and presentation. The intersection of the results from machine learning revealed that SERPINA3, GPAT3, ANPEP, and FCER1G can serve as feature genes and form a diagnostic model with a good predictive capability. Unsupervised consensus clustering algorithms reveal the immune and metabolic subtypes of macrophages. The metabolic heterogeneity of macrophage subpopulations can lead to macrophage polarization into different types, which may be related to the metabolic reprogramming between glycolysis and mitochondrial oxidative phosphorylation. Cellular communication revealed that macrophages form a network of interactions with neutrophils to support each other's functions and maintenance. The complex efferent and afferent signals are closely associated with myocardial fibrosis.

Conclusion

SERPINA3, GPAT3, ANPEP, and FCER1G can potentially serve as immune therapeutic targets and central biomarkers. The immunological and metabolic heterogeneity of macrophages may offer a more precise direction to explore the mechanisms underlying HF and novel immunotherapies.

WITHDRAWN: Myocardial Fibrosis in Diabetic Cardiomyopathy: Mechanisms, Implications, and Therapeutic Perspectives

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An antioxidant nanozyme for targeted cardiac fibrosis therapy post myocardial infarction

The excessive release of reactive oxygen species (ROS) after myocardial infarction (MI) disrupts the natural healing process, leading to cardiac fibrosis and compromising patient prognosis. However, the clinical application of many antioxidant drugs for MI treatment is hindered by their poor antioxidant efficacy and inability to specifically target the heart. Here we developed a tannic acid-modified MnO2 nanozyme (named MnO2@TA), which can achieve cardiac targeting to inhibit post-MI fibrosis and enhance cardiac function. Specifically, the MnO2@TA nanozyme, endowed with superoxide dismutase (SOD) and catalase (CAT) activities, effectively scavenges ROS, suppressing fibroblast activation and mitigating cardiac fibrosis without affecting cardiac repair. Notably, the incorporation of TA improves the nanozyme's affinity for the elastin and collagen-rich extracellular matrix in cardiac tissues, significantly increasing its retention and uptake within the heart and thereby enhancing its anti-fibrotic efficacy. In a murine myocardial infarction model, MnO2@TA demonstrates remarkable cardiac protection and safety, significantly improving cardiac function while attenuating cardiac fibrosis. This study presents a valuable reference for clinical research aimed at inhibiting cardiac fibrosis and advancing myocardial infarction treatments.

Quercetin Alleviates Cardiac Fibrosis via Regulating the SIRT3 Signaling Pathway

PURPOSE

Cardiovascular diseases, exacerbated by cardiac fibrosis, are the leading causes of mortality. We aimed to determine the role of quercetin (QU) in cardiac fibrosis and the underlying mechanism.

METHODS

In this study, 8-week-old mice were subjected to either transverse aortic constriction (TAC) or sham surgery, then they were administered QU or saline. Thereafter, cardiac function and cardiac hypertrophy were accessed. In vitro, cardiac fibroblasts (CFs) were treated with angiotensin II (Ang II) with or without QU. Western blot, qPCR, EdU incorporation assay, and immunofluorescence staining analysis were used to investigate the molecular and cellular features.

RESULTS

For the TAC mouse model, cardiac fibrosis was alleviated by QU. The study revealed that the trans-differentiation and proliferation of CFs promoted by Ang II would be reversed by QU in vitro. Mechanistically, QU exerted the anti-fibrotic effect by regulating the SIRT3/TGF-β/Smad3 signaling pathway.

CONCLUSION

Quercetin protects against cardiac fibrosis by mediating the SIRT3 signaling pathway.

Epigenetic regulation of mitochondrial fission and cardiac fibrosis via sFRP3 promoter methylation

In the process of cardiac fibrosis, the balance between the Wnt/β-catenin signalling pathway and Wnt inhibitory factor genes plays an important role. Secreted frizzled-related protein 3 (sFRP3), a Wnt inhibitory factor, has been linked to epigenetic mechanisms. However, the underlying role of epigenetic regulation of sFRP3, which is crucial in fibroblast proliferation and migration, in cardiac fibrosis have not been elucidated. Therefore, we aimed to investigate epigenetic and transcription of sFRP3 in cardiac fibrosis. Using clinical samples and animal models, we investigated the role of sFRP3 promoter methylation in potentially enhancing cardiac fibrosis. We also attempted to characterize the underlying mechanisms using an isoprenaline-induced cardiac fibrosis mouse model and cultured primary cardiac fibroblasts. Hypermethylation of sFRP3 was associated with perpetuation of fibroblast activation and cardiac fibrosis. Additionally, mitochondrial fission, regulated by the Drp1 protein, was found to be significantly altered in fibrotic hearts, contributing to fibroblast proliferation and cardiac fibrosis. Epigenetic modification of sFRP3 promoter methylation also influenced mitochondrial dynamics, linking sFRP3 repression to excessive mitochondrial fission. Moreover, sFRP3 hypermethylation was mediated by DNA methyltransferase 3A (DNMT3A) in cardiac fibrosis and fibroblasts, and DNMT3A knockdown demethylated the sFRP3 promoter, rescued sFRP3 loss, and ameliorated the isoprenaline-induced cardiac fibrosis and cardiac fibroblast proliferation, migration and mitochondrial fission. Mechanistically, DNMT3A was shown to epigenetically repress sFRP3 expression via promoter methylation. We describe a novel epigenetic mechanism wherein DNMT3A represses sFRP3 through promoter methylation, which is a critical mediator of cardiac fibrosis and mitochondrial fission. Our findings provide new insights for the development of preventive measures for cardiac fibrosis.

Features of cardiovascular magnetic resonance native T1 mapping in maintenance hemodialysis patients and their related factors

PURPOSE

Increased myocardial T1 values on cardiovascular MRI (CMRI) have been shown to be a surrogate marker for myocardial fibrosis. The use of CMRI in patients on hemodialysis (HD) remains limited. This research aimed to explore the characteristics of native T1 values in HD patients and identify factors related to T1 values.

METHODS

A total of thirty-two patients on HD and fourteen healthy controls were included in this study. All participants underwent CMRI. Using modified Look-Locker inversion recovery (MOLLI) sequence, native T1 mapping was achieved. Native CMRI T1 values were compared between the two groups. In order to analyze the relationship between T1 values and clinical parameters, correlation analysis was performed in patients on HD.

RESULTS

Patients on HD exhibited elevated global native T1 values compared to control subjects. In the HD group, the global native T1 value correlated positively with intact parathyroid hormone (iPTH) (r = 0.418, p = 0.017) and negatively with triglycerides (r= -0.366, p = 0.039). Moreover, the global native T1 value exhibited a positive correlation with the left ventricular end-diastolic volume indexed to body surface area (BSA; r = 0.528, p = 0.014), left ventricular end-systolic volume indexed to BSA (r = 0.506, p = 0.019), and left ventricular mass indexed to BSA (r = 0.600, p = 0.005). A negative correlation was observed between the global native T1 value and ejection fraction (r = 0.-0.551, p = 0.010).

CONCLUSION

The global native T1 value was prolonged in HD patients compared with controls. In the HD group, the global T1 value correlated strongly with iPTH, triglycerides, and cardiac structural and functional parameters.

Pathobiology of myocardial and cardiomyocyte injury in ischemic heart disease: Perspective from seventy years of cell injury research

This review presents a perspective on the pathobiology of acute myocardial infarction, a major manifestation of ischemic heart disease, and related mechanisms of ischemic and toxic cardiomyocyte injury, based on advances and insights that have accrued over the last seventy years, including my sixty years of involvement in the field as a physician-scientist-pathologist. This analysis is based on integration of my research within the broader context of research in the field. A particular focus has been on direct measurements in cardiomyocytes of electrolyte content by electron probe X-ray microanalysis (EPXMA) and Ca2+ fluxes by fura-2 microspectrofluorometry. These studies established that increased intracellular Ca2+ develops at a transitional stage in the progression of cardiomyocyte injury in association with ATP depletion, other electrolyte alterations, altered cell volume regulation, and altered membrane phospholipid composition. Subsequent increase in total calcium with mitochondrial calcium accumulation can occur. These alterations are characteristic of oncosis, which is an initial pre-lethal state of cell injury with cell swelling due to cell membrane dysfunction in ATP depleted cells; oncosis rapidly progresses to necrosis/necroptosis with physical disruption of the cell membrane, unless the adverse stimulus is rapidly reversed. The observed sequential changes fit a three-stage model of membrane injury leading to irreversible cell injury. The data establish oncosis as the primary mode of cardiomyocyte injury in evolving myocardial infarcts. Oncosis also has been documented to be the typical form of non-ischemic cell injury due to toxins. Cardiomyocytes with less energy impairment have the capability of undergoing apoptosis and autophagic death as well as oncosis, as is seen in pathological remodeling in chronic heart failure. Work is ongoing to apply the insights from experimental studies to better understand and ameliorate myocardial ischemia and reperfusion injury in patients. The perspective and insights in this review are derived from basic principles of pathology, an integrative discipline focused on mechanisms of disease affecting the cell, the organizing unit of living organisms.

Silencing DOCK2 Attenuates Cardiac Fibrosis Following Myocardial Infarction in Mice Via Targeting PI3K/Akt and Wnt/β-Catenin Pathways

Cardiac fibrosis following myocardial infarction (MI) seriously affects the prognosis and survival rate of patients. This study aimed to determine the effect and regulation mechanism of the dedicator of cytokinesis 2 (DOCK2) during this process. Experiments were carried out in mice in vivo, and in Ang II treated cardiac fibroblasts (CFs) in vitro. DOCK2 was increased in mouse myocardial tissues after MI and Ang II-treated CFs. In MI mice, DOCK2 silencing improved cardiac function, and ameliorated cardiac fibrosis. DOCK2 knockdown suppressed the activation of CFs and decreased the expression of α-SMA, collagen I, and collagen III. Suppression of DOCK2 mitigated Ang II induced migration of CFs. DOCK2 inhibition reduced the activity of the PI3K/Akt and Wnt/β-catenin pathways, while this change could be reversed by the pathway activators, SC79 and SKL2001. In summary, DOCK2 suppression improves cardiac dysfunction and attenuates cardiac fibrosis after MI via attenuating PI3K/Akt and Wnt/β-catenin pathways.

Single-cell transcriptomics reveal distinctive patterns of fibroblast activation in heart failure with preserved ejection fraction

Inflammation, fibrosis and metabolic stress critically promote heart failure with preserved ejection fraction (HFpEF). Exposure to high-fat diet and nitric oxide synthase inhibitor N[w]-nitro-l-arginine methyl ester (L-NAME) recapitulate features of HFpEF in mice. To identify disease-specific traits during adverse remodeling, we profiled interstitial cells in early murine HFpEF using single-cell RNAseq (scRNAseq). Diastolic dysfunction and perivascular fibrosis were accompanied by an activation of cardiac fibroblast and macrophage subsets. Integration of fibroblasts from HFpEF with two murine models for heart failure with reduced ejection fraction (HFrEF) identified a catalog of conserved fibroblast phenotypes across mouse models. Moreover, HFpEF-specific characteristics included induced metabolic, hypoxic and inflammatory transcription factors and pathways, including enhanced expression of Angiopoietin-like 4 (Angptl4) next to basement membrane compounds, such as collagen IV (Col4a1). Fibroblast activation was further dissected into transcriptional and compositional shifts and thereby highly responsive cell states for each HF model were identified. In contrast to HFrEF, where myofibroblast and matrifibrocyte activation were crucial features, we found that these cell states played a subsidiary role in early HFpEF. These disease-specific fibroblast signatures were corroborated in human myocardial bulk transcriptomes. Furthermore, we identified a potential cross-talk between macrophages and fibroblasts via SPP1 and TNFɑ with estimated fibroblast target genes including Col4a1 and Angptl4. Treatment with recombinant ANGPTL4 ameliorated the murine HFpEF phenotype and diastolic dysfunction by reducing collagen IV deposition from fibroblasts in vivo and in vitro. In line, ANGPTL4, was elevated in plasma samples of HFpEF patients and particularly high levels associated with a preserved global-longitudinal strain. Taken together, our study provides a comprehensive characterization of molecular fibroblast activation patterns in murine HFpEF, as well as the identification of Angiopoietin-like 4 as central mechanistic regulator with protective effects.

Schisandrin C prevents regorafenib-induced cardiotoxicity by recovering EPHA2 expression in cardiomyocytes

Regorafenib, an oral multikinase inhibitor of angiogenic, stromal, and oncogenic receptor tyrosine kinases, has been approved for the treatment of metastatic colorectal cancer, gastrointestinal stromal tumors, and hepatocellular carcinoma by the US Food and Drug Administration and European Medicines Agency. However, regorafenib-induced cardiotoxicity increases the risk of mortality. Despite reports that regorafenib can cause mitochondrial dysfunction in cardiomyocytes, the molecular mechanism of regorafenib-induced cardiotoxicity is much less known and there is an urgent need for intervention strategies. Here, we treated mice with vehicle or 200 mg/kg regorafenib daily for 42 d by gavage or treated cardiomyocyte lines with 8, 16, or 32 μM regorafenib, and we found that regorafenib could cause apoptosis, mitochondrial injury, and DNA damage in cardiomyocytes. Mechanistically, regorafenib can reduce the expression of EPHA2, which inhibits AKT signaling, leading to cardiomyocyte apoptosis and cardiotoxicity. In addition, we showed that recovering EPHA2 expression via plasmid-induced overexpression of EPHA2 or schisandrin C, a natural product, could prevent regorafenib-induced cardiotoxicity. These findings demonstrated that regorafenib causes cardiomyocyte apoptosis and cardiac injury by reducing the expression of EPHA2 and schisandrin C could prevent regorafenib-induced cardiotoxicity by recovering EPHA2 expression, which provides a potential management strategy for regorafenib-induced cardiotoxicity and will benefit the safe application of regorafenib in clinic.

Bushen Huoxue Yiqi formula alleviates cardiac fibrosis in ischemic heart failure through SIRT1/Notch1 pathway-mediated EndMT

BACKGROUND

Cardiac fibrosis plays a crucial role in the development of heart failure (HF) following myocardial infarction (MI). Endothelial-mesenchymal transition (EndMT) is one of the key drivers of cardiac fibrosis and subsequent cardiac dysfunction. The traditional Chinese medicine formula Bushen Huoxue Yiqi Formula (BHYF) is an effective prescription for treating HF, significantly improving cardiac function in patients. However, the underlying mechanisms of BHYF's efficacy remain inadequately understood.

OBJECTIVE

This study aims to determine whether BHYF ameliorates HF by inhibiting cardiac fibrosis and to elucidate the intrinsic mechanisms involved.

METHODS

A post-MI HF model was established by ligating the left anterior descending coronary artery in rats, and human umbilical vein endothelial cells (HUVEC) were stimulated with hypoxia/reoxygenation (H/R) in vitro. Active compounds in BHYF were identified using HPLC. Cardiac function and morphology were assessed using echocardiography, TTC staining, HE staining, Masson's trichrome, and Sirius Red staining. The mechanism of action of BHYF was evaluated using Western blotting, immunohistochemistry, and immunofluorescence.

RESULTS

A total of 98 compounds, including glycosides, phenolic compounds, carboxylic acids, and others, were identified or preliminarily identified. BHYF improved cardiac function and myocardial damage in rats with MI-induced HF and mitigated cardiac fibrosis by inhibiting EndMT. Mechanistically, BHYF treatment inhibited EndMT by modulating the SIRT1/Notch1 pathway, thereby exerting anti-fibrotic effects in the heart.

CONCLUSION

Targeting EndMT based on the SIRT1/Notch1 pathway, BHYF may represent a novel antifibrotic therapeutic strategy, providing a scientific basis for the development of new cardiovascular drugs.