Cardiac Pericytes Acquire a Fibrogenic Phenotype and Contribute to Vascular Maturation After Myocardial Infarction

Construction of AgNPs-loaded oriented hydrogel based on Periostracum Cicadae chitosan by electro-assembly for rapid hemostasis and wound healing

Oriented hydrogels have been recognized for their ability to promote cell proliferation and enhance wound repair. Chitosan, valued for its biocompatibility and biodegradability, is widely used in hydrogel preparation. However, chitosan derived from Periostracum Cicadae ("Chantui") has not been explored for creating antibacterial-oriented hydrogels. In this study, we successfully developed a Periostracum Cicadae chitosan-based oriented hydrogel (O-CH) using an electro-assembly method. The O-CH hydrogel exhibited superior hemostatic performance and mechanical strength, with stress levels 7.6 times higher than those of traditional alkali-neutralized hydrogels. Subsequently, silver nanoparticles (AgNPs) were formed in situ on the O-CH hydrogel without the need for additional reducing agents or stabilizers, yielding O-CH@Ag20, which exhibited excellent biocompatibility and enhanced antibacterial properties. In an S. aureus-infected full-thickness rat skin defect model, O-CH@Ag20 reduced bacterial counts at the wound site by 6-fold compared to the gauze group on day 3 and achieved a 97 % wound healing rate by day 10, versus 75 % in the gauze group. Histological analysis revealed that O-CH@Ag20 regulated angiogenesis, collagen deposition, and fibroblast differentiation into myofibroblasts, thereby accelerating wound contraction during remodeling. This study presents a novel approach to addressing clinical challenges in infected wound healing using Periostracum Cicadae chitosan-based antibacterial hydrogels.

Cardiovascular dysfunction and altered lysosomal signaling in a murine model of acid sphingomyelinase deficiency

Niemann-Pick Disease (NPD) is a rare autosomal recessive lysosomal storage disorder (LSD) caused by the deficiency of acid sphingomyelinase (ASMD), which is encoded by the Smpd1 gene. ASMD impacts multiple organ systems in the body, including the cardiovascular system. This study is the first to characterize cardiac pathological changes in ASMD mice under baseline conditions, offering novel insights into the cardiac implications of NPD. Using histological analysis, biochemical assays, and echocardiography, we assessed cardiac pathological changes and function in Smpd1-/- mice compared to Smpd1+/+ littermate controls. Immunofluorescence and biochemical assays demonstrated that ASMD induced lysosomal dysfunction, as evidenced by the accumulation of lysosomal-associated membrane proteins, lysosomal protease, and autophagosomes in pericytes and cardiomyocytes. This lysosomal dysfunction was accompanied by pericytes and cardiomyocytes inflammation, characterized by increased expression of caspase1 and inflammatory cytokines, and infiltration of inflammatory cells in the cardiac tissues of Smpd1-/- mice. In addition, histological analysis revealed increased lipid deposition and cardiac steatosis, along with pericyte-to-myofibroblast transition (PMT) and interstitial fibrosis in Smpd1-/- mice. Moreover, echocardiography further demonstrated that Smpd1-/- mice developed coronary microvascular dysfunction (CMD), as evidenced by decreased coronary blood flow velocity and increased coronary arteriolar wall thickness. Additionally, these mice exhibited significant impairments in systolic and diastolic cardiac function, as shown by a reduced ejection fraction and prolonged left ventricular relaxation time constant (Tau value). These findings suggest that ASMD induces profound pathological changes and vascular dysfunction in the myocardium, potentially driven by mechanisms involving lysosomal dysfunction as well as both pericytes and cardiac inflammation. KEY MESSAGES: Lysosomal dysfunction in ASMD leads to impaired autophagic flux in cardiac pericytes ASMD causes cardiac inflammation with leukocyte and M2 macrophage infiltration Lipid buildup in the pericytes, fibroblasts and myocardium lead to cardiac steatosis Enhanced cardiac fibrosis in ASMD links to pericyte-to-myofibroblast transition ASMD results in coronary microvascular and diastolic and systolic cardiac dysfunction.

Cardiac Fibrosis in the Multi-Omics Era: Implications for Heart Failure

Cardiac fibrosis, a hallmark of heart failure and various cardiomyopathies, represents a complex pathological process that has long challenged therapeutic intervention. High-throughput omics technologies have begun revolutionizing our understanding of the molecular mechanisms driving cardiac fibrosis and are providing unprecedented insights into its heterogeneity and progression. This review provides a comprehensive analysis of how techniques-encompassing genomics, epigenomics, transcriptomics, proteomics, and metabolomics-are providing insight into our understanding of cardiac fibrosis. Genomic studies have identified novel genetic variants and regulatory networks associated with fibrosis susceptibility and progression, and single-cell transcriptomics has unveiled distinct cardiac fibroblast subpopulations with unique molecular signatures. Epigenomic profiling has revealed dynamic chromatin modifications controlling fibroblast activation states, and proteomic analyses have identified novel biomarkers and potential therapeutic targets. Metabolomic studies have uncovered important alterations in cardiac energetics and substrate utilization during fibrotic remodeling. The integration of these multi-omic data sets has led to the identification of previously unrecognized pathogenic mechanisms and potential therapeutic targets, including cell-type-specific interventions and metabolic modulators. We discuss how these advances are driving the development of precision medicine approaches for cardiac fibrosis while highlighting current challenges and future directions in translating multi-omic insights into effective therapeutic strategies. This review provides a systems-level perspective on cardiac fibrosis that may inform the development of more effective, personalized therapeutic approaches for heart failure and related cardiovascular diseases.

Cardiovascular Dysfunction and Altered Lysosomal Signaling in a Murine Model of Acid Sphingomyelinase Deficiency

Niemann-Pick Disease (NPD) is a rare autosomal recessive lysosomal storage disorder (LSD) caused by the deficiency of acid sphingomyelinase (ASMD), which is encoded by the Smpd1 gene. ASMD impacts multiple organ systems in the body, including the cardiovascular system. This study is the first to characterize cardiac pathological changes in ASMD mice under baseline conditions, offering novel insights into the cardiac implications of NPD. Using histological analysis, biochemical assays, and echocardiography, we assessed cardiac pathological changes and function in Smpd1 -/- mice compared to Smpd1 +/+ littermate controls. Immunofluorescence and biochemical assays demonstrated that ASMD induced lysosomal dysfunction, as evidenced by the accumulation of lysosomal-associated membrane proteins, lysosomal protease, and autophagosomes in pericytes and cardiomyocytes. This lysosomal dysfunction was accompanied by pericytes and cardiomyocytes inflammation, characterized by increased expression of caspase1 and inflammatory cytokines, and infiltration of inflammatory cells in the cardiac tissues of Smpd1 -/- mice. In addition, histological analysis revealed increased lipid deposition and cardiac steatosis, along with pericyte-to-myofibroblast transition (PMT) and interstitial fibrosis in Smpd1 -/- mice. Moreover, echocardiography further demonstrated that Smpd1 -/- mice developed coronary microvascular dysfunction (CMD), as evidenced by decreased coronary blood flow velocity and increased coronary arteriolar wall thickness. Additionally, these mice exhibited significant impairments in systolic and diastolic cardiac function, as shown by a reduced ejection fraction and prolonged left ventricular relaxation time constant (Tau value). These findings suggest that ASMD induces profound pathological changes and vascular dysfunction in the myocardium, potentially driven by mechanisms involving lysosomal dysfunction as well as both pericytes and cardiac inflammation.

Cilostazol alleviates imatinib-induced myocardial injury in rats by modulating the TGF-β1/MAPK, SHC/Grb2/SOS signaling pathways and upregulating miRNA-195-5P

Tyrosine kinase inhibitors have revolutionized cancer treatment, yet their association with cardiotoxicity remains a challenge. While the pathophysiological consequences of imatinib therapy involve diverse pathways, our understanding of these mechanisms is limited. Cilostazol, a selective phosphodiesterase 3 inhibitor used in intermittent claudication treatment, is known for its antioxidant and anti-inflammatory effects. In this study, we aimed to counteract the cardiotoxic effects of imatinib by administering cilostazol, concurrently investigating the precise mechanisms underlying imatinib-induced myocardial injury. Twenty-eight male Wistar rats were categorized into four groups: control (2 mL/kg normal saline, orally), cilostazol (10 mg/kg, orally), imatinib (40 mg/kg, intraperitonially), and combination (cilostazol and imatinib). Daily treatments were administered for 28 consecutive days. Imatinib therapy induced oxidative stress, pro-inflammatory responses, and cardiotoxicity biomarkers, alongside dysregulation of various protein and gene expressions. The addition of cilostazol to imatinib mitigated these deleterious effects, notably restoring measured biomarkers close to normal values. Histopathological investigations corroborated the biochemical findings. The co-administration of cilostazol with imatinib effectively protects against imatinib-induced myocardial injury in rats, reducing oxidative stress, apoptotic and inflammatory biomarkers, and modulating protein, gene, and miRNA-195-5p expression levels. While promising for alleviating and protecting against myocardial injury in imatinib-treated patients, these findings necessitate further confirmation through clinical studies.

Dynamic responses to rejection in the transplanted human heart revealed through spatial transcriptomics

Allograft rejection following solid-organ transplantation is a major cause of graft dysfunction and mortality. Current approaches to diagnosis rely on histology, which exhibits wide diagnostic variability and lacks access to molecular phenotypes that may stratify therapeutic response. Here, we leverage image-based spatial transcriptomics at sub-cellular resolution in longitudinal human cardiac biopsies to characterize transcriptional heterogeneity in 62 adult and pediatric heart transplant (HT) recipients during and following histologically-diagnosed rejection. Across 28 cell types, we identified significant differences in abundance in CD4 + and CD8 + T cells, fibroblasts, and endothelial cells across different biological classes of rejection (cellular, mixed, antibody-mediated). We observed a broad overlap in cellular transcriptional states across histologic rejection severity and biological class and significant heterogeneity within rejection severity grades that would qualify for immunomodulatory treatment. Individuals who had resolved rejection after therapy had a distinct transcriptomic profile relative to those with persistent rejection, including 216 genes across 6 cell types along pathways of inflammation, IL6-JAK-STAT3 signaling, IFNα/IFNγ response, and TNFα signaling. Spatial transcriptomics also identified genes linked to long-term prognostic outcomes post-HT. These results underscore importance of subtyping immunologic states during rejection to stratify immune-cardiac interactions following HT that are therapeutically relevant to short- and long-term rejection-related outcomes.

Emerging role of mesenchymal cells in cardiac and cerebrovascular diseases: Physiology, pathology, and therapeutic implications

In recent years, the therapeutic utility of mesenchymal stem cells (MSCs) has received substantial attention from investigators, owing to their pleiotropic properties. The emerging insights from the developments in tissue engineering provide perspectives for the repair of damaged tissue and the replacement of failing organs. Perivascular cells including MSC-like pericytes, vascular smooth muscles, and other cells located around blood vessels, have been acknowledged to contribute to in situ angiogenesis and repair process. MSCs offer a wide array of therapeutic applications in different pathological states. However, in the current article, we have highlighted the recent updates on MSCs and their key applications in cardiac and cerebrovascular diseases, evident in different preclinical and clinical studies. We believe the present article would assist the investigators in understanding the recent advances of MSCs and exploring their therapeutic potential in varied ailments, especially cardiac and cerebrovascular diseases.

Mural cell dysfunction contributes to diastolic heart failure by promoting endothelial dysfunction and vessel remodelling

BACKGROUND

Heart failure with preserved ejection fraction (HFpEF) is a complex cardiovascular disease associated with metabolic comorbidities. Microvascular dysfunction has been proposed to drive HFpEF, likely via endothelial cell (EC) dysfunction, yet the role of the mural cells herein has never been explored.

METHODS

We used the diabetic db/db mouse given 1% salt as a new model of HFpEF and crossed then with PDGFRβtg/tg-CreERT2-EYFPtg/tg mice to label the mural cells. We combined single-cell RNA sequencing, NichetNet analysis and histology to determine the role of mural cell dysfunction in HFpEF.

RESULTS

Db/db mice given 1% salt for 8 weeks developed diastolic dysfunction preceded by capillary density loss, pericyte loss and vessel regression. At 4 weeks of salt, hearts of db/db mice already showed EC dysfunction associated with an anti-angiogenic signature, and an increase in pericyte-EC intracellular space. Db/db + salt hearts were further characterised by increased ACTA2 expression, arteriole wall thickening and vessel enlargement. NicheNet analysis on the single cell transcriptomic data revealed little signalling from the ECs to the mural cells; instead, mural cells signalled strongly to ECs. Mechanistically, pericyte dysfunction induces an EC growth arrest via TNFα-dependent paracrine signalling and downstream signalling through STAT1.

CONCLUSION

Mural cell dysfunction contributes to HFpEF by inducing coronary vessel remodelling, at least in part by reducing EC proliferation and inducing EC inflammation through TNFα-dependent paracrine signalling.

Analysis of cellular NO-GC expression in the murine heart and lineage determination in angiotensin II-induced fibrosis

NO-sensitive guanylyl cyclase (NO-GC) is involved in the (patho)physiology of the mammalian heart. However, little is known about the individual cardiac cell types that express NO-GC and the role of the enzyme in cardiac fibrosis. Here, we describe the cellular expression of NO-GC in healthy and fibrotic murine myocardium; these data were compared with scRNA-seq data. In healthy myocardium, NO-GC is strongly expressed in pericytes and smooth muscle cells but not in endothelial cells or cardiomyocytes. Angiotensin II induced cardiac hypertrophy and fibrosis; fibrotic lesions contained cells positive for NO-GC identified as activated fibroblasts. Lineage tracing indicates that NO-GC-expressing activated fibroblasts originate from PDGFRβ- and Tcf21-positive fibroblast precursors. Our data indicate NO-GC expression in cardiac pericytes and SMC in naive myocardium and in activated fibroblast in fibrotic heart tissue. NO-mediated signaling may modulate fibrotic responses underlying the action of NO-GC stimulators used in the therapy of heart failure.

Indole-3-Lactic Acid Inhibits Doxorubicin-Induced Ferroptosis Through Activating Aryl Hydrocarbon Receptor/Nrf2 Signalling Pathway

The clinical application of doxorubicin (DOX) is limited due to its cardiotoxicity, which is primarily attributed to its interaction with iron in mitochondria, leading to lipid peroxidation and myocardial ferroptosis. This study aimed to investigate the role of the gut microbiota-derived metabolite, indole-3-lactic acid (ILA), in mitigating DOX-induced cardiotoxicity (DIC). Cardiac function, pathological changes, and myocardial ferroptosis were assessed in vivo. The cardioprotective effects and mechanisms of ILA were explored using multi-omics approaches, including single-nucleus RNA sequencing (snRNA-seq) and bulk RNA-seq, and were further validated in Nrf2 knockout mice. The findings revealed that DOX treatment disrupted gut microbiota, significantly reducing the levels of the tryptophan metabolite ILA. In DIC models, ILA supplementation markedly improved cardiac function, reduced collagen deposition, and mitigated cardiac atrophy. The bulk and snRNA-seq analyses indicated that myocardial ferroptosis played a crucial role in the cardioprotective effects of ILA. Experimental data demonstrated that ILA decreased DOX-induced ferroptosis in both DIC mice and DOX-treated H9C2 cells, evidenced by restoration of GPX4 and SLC7A11 levels and reduction of ACSL4. Mechanistically, ILA functions as a ligand for the aryl hydrocarbon receptor (AhR), leading to the upregulation of Nrf2 expression. The protective effects of ILA against ferroptosis were abolished by silencing AhR. Moreover, the beneficial effects of ILA on DIC were eliminated in Nrf2-deficient mice. In conclusion, ILA exerts therapeutic effects against DIC by inhibiting ferroptosis through activation of the AhR/Nrf2 signalling pathway. Identifying the cardioprotective role of the microbial metabolite ILA could offer viable therapeutic strategies for DIC.

Hypertension research 2024 update and perspectives: basic research

This review article introduces some basic studies that were recently published in this journal, as a part of Hypertension Research 2024 Update and Perspectives. Including recent basic research trends in other scientific journals, we would like to summarize basic research on keywords such as hypertension and its associated organ damage, new treatments, and others. It is expected that the accumulation of basic studies will lead to breakthroughs in hypertension treatment in the future and lead to the definitive treatment of hypertension beyond blood pressure control with anti-hypertensive drugs.

Peroxynitrite-Free Nitric Oxide-Embedded Nanoparticles Maintain Nitric Oxide Homeostasis for Effective Revascularization of Myocardial Infarcts

Revascularization is crucial for treating myocardial infarction (MI). Nitric oxide (NO), at an appropriate concentration, is recognized as an ideal and potent pro-angiogenic factor. However, the application of NO in the treatment of MI is limited. Improper NO supplementation is harmful to revascularization because NO is converted into harmful peroxynitrite (ONOO-) in MI tissues with high reactive oxygen species (ROS) levels. We overcome these obstacles by embedding biliverdin and NO into Prussian blue (PB) nanolattices to obtain an ONOO--free NO-embedded nanomedicine (OFEN). Unlike previous NO donors, OFEN provides NO stably and spontaneously for a longer time (>7 days), which makes it possible to maintain a stable concentration of NO, suitable for angiogenesis, through dose optimization. More importantly, based on the synergy between PB and biliverdin, OFEN converts ROS into beneficial O2 and inhibits the production of ONOO- from the source. OFEN specifically targets MI tissues and achieves sustained and stable NO delivery at the MI site. OFEN effectively promotes revascularization in the MI tissue, significantly reduces myocardial death and fibrosis, and ultimately promotes the complete recovery of cardiac function. Our strategy provides a promising approach for the treatment of myocardial and other ischemic diseases.

Heart regeneration from the whole-organism perspective to single-cell resolution

Cardiac regenerative potential in the animal kingdom displays striking divergence across ontogeny and phylogeny. Here we discuss several fundamental questions in heart regeneration and provide both a holistic view of heart regeneration in the organism as a whole, as well as a single-cell perspective on intercellular communication among diverse cardiac cell populations. We hope to provide valuable insights that advance our understanding of organ regeneration and future therapeutic strategies.

Novel Agonists of Adenosine Receptors in Animal Model of Acute Myocardial Infarction

Background and Purpose

Current treatments for acute myocardial infarction (AMI) include pain relief and attempts to improve survival. This study investigated the effects of two new ligands of the adenosine receptor, LASSBio-1027 and LASSBio-1860, on cardiac function in an experimental model of AMI.

Methods

AMI was induced in Wistar rats by ligating the anterior descending coronary arteries. Infarcted animals were treated orally with vehicle (DMSO), LASSBio-1027 (30 and 70 μmol/kg), or LASSBio-1860 (70 μmol/kg) for seven days. Hemodynamic parameters were observed using echocardiography, whereas inflammation and fibrosis were detected using histological analysis.

Results

MI increased the filling pressure from 23.0 ± 1.6 and 14.0 ± 2.0 to 37.0 ± 3.7 and 33.2 ± 8.0, respectively indicating diastolic dysfunction. However, treatment with LASSBio-1027 (70 μmol/kg) and LASSBio-1860 (70 μmol/kg) reduced this parameter to 23.9 ± 5.4 and 17.1 ± 6.7. An impairment in ejection fraction from 57.1 ± 3.2 to 36.6 ± 2.0% was observed after MI, partially recovered to 47.0 ± 7.4% by LASSBio-1027 and fully restored to 61.8 ± 4.3% after 7 days of treatment with LASSBio-1860. After MI, collagen deposition in LV free wall was increased to 31.4 ± 11.0% and treatment with LASSBio-1027 reduced to 23.4 ± 6.0 and 19.7 ± 8.0% at 30 and 70 μmol/kg, respectively. Similarly, LASSBio-1860 reduced collagen levels to 63.1 ± 2.0%.

Conclusion

Fibrosis and inflammatory components of MI reduced following treatment with agonist of adenosine receptor subtype A2A. Cardiac remodeling induced by LASSBio-1027 and LASSBio-1860 may be responsible for the improvement in cardiac function in AMI through the activation of A2A adenosine receptors.

Unveiling the Heart's Hidden Enemy: Dynamic Insights into Polystyrene Nanoplastic-Induced Cardiotoxicity Based on Cardiac Organoid-on-a-Chip

Exposure to micro- and nanoplastics (MNPs) has been implicated in potential cardiotoxicity. However, in vitro models based on cardiomyocyte cell lines lack crucial cardiac characteristics, while interspecies differences in animal models compromise the reliability of the conclusions. In addition, current research has predominantly focused on single-time point exposures to MNPs, neglecting comparative analyses of cardiac injury across early and late stages. Moreover, there remains a large gap in understanding the susceptibility to MNPs under pathological conditions. To address these limitations, this study integrated cardiac organoids (COs) and organ-on-a-chip (OoC) technology to develop the cardiac organoid-on-a-chip (COoC), which was validated for cardiotoxicity evaluation through multiple dimensions. Based on COoC, we conducted a dynamic observation of the cardiac damage caused by short- and long-term exposure to polystyrene nanoplastics (PS-NPs). Oxidative stress, inflammation, disruption of calcium ion homeostasis, and mitochondrial dysfunction were confirmed as the potential mechanisms of PS-NP-induced cardiotoxicity and the crucial events in the early stages, while cardiac fibrosis emerged as a prominent feature in late stages. Notably, low-dose exposure exacerbated myocardial infarction symptoms under pathological states, despite no significant cardiotoxicity shown in healthy models. In conclusion, these findings further deepened our understanding of PS-NP-induced cardiotoxic effects and introduced a promising in vitro platform for assessing cardiotoxicity.

SMAD3 mediates the specification of human induced pluripotent stem cell-derived epicardium into progenitors for the cardiac pericyte lineage

Understanding the molecular mechanisms of epicardial epithelial-to-mesenchymal transition (EMT), particularly in directing cell fate toward epicardial derivatives, is crucial for regenerative medicine using human induced pluripotent stem cell (iPSC)-derived epicardium. Although transforming growth factor β (TGF-β) plays a pivotal role in epicardial biology, orchestrating EMT during embryonic development via downstream signaling through SMAD proteins, the function of SMAD proteins in the epicardium in maintaining vascular homeostasis or mediating the differentiation of various epicardial-derived cells (EPDCs) is not yet well understood. Our study reveals that TGF-β-independent SMAD3 expression autonomously predicts epicardial cell specification and lineage maintenance, acting as a key mediator in promoting the angiogenic-oriented specification of the epicardium into cardiac pericyte progenitors. This finding uncovers a novel role for SMAD3 in the human epicardium, particularly in generating cardiac pericyte progenitors that enhance cardiac microvasculature angiogenesis. This insight opens new avenues for leveraging epicardial biology in developing more effective cardiac regeneration strategies.

The Role of Pericytes in Inner Ear Disorders: A Comprehensive Review

Inner ear disorders, including sensorineural hearing loss, Meniere's disease, and vestibular neuritis, are prevalent conditions that significantly impact the quality of life. Despite their high incidence, the underlying pathophysiology of these disorders remains elusive, and current treatment options are often inadequate. Emerging evidence suggests that pericytes, a type of vascular mural cell specialized to maintain the integrity and function of the microvasculature, may play a crucial role in the development and progression of inner ear disorders. The pericytes are present in the microvasculature of both the cochlea and the vestibular system, where they regulate blood flow, maintain the blood-labyrinth barrier, facilitate angiogenesis, and provide trophic support to neurons. Understanding their role in inner ear disorders may provide valuable insights into the pathophysiology of these conditions and lead to the development of novel diagnostic and therapeutic strategies, improving the standard of living. This comprehensive review aims to provide a detailed overview of the role of pericytes in inner ear disorders, highlighting the anatomy and physiology in the microvasculature, and analyzing the mechanisms that contribute to the development of the disorders. Furthermore, we explore the potential pericyte-targeted therapies, including antioxidant, anti-inflammatory, and angiogenic approaches, as well as gene therapy strategies.

Endothelial Cell-Specific Prolyl Hydroxylase-2 Deficiency Augments Angiotensin II-Induced Arterial Stiffness and Cardiac Pericyte Recruitment in Mice

BACKGROUND

Endothelial prolyl hydroxylase-2 (PHD2) is essential for pulmonary remodeling and hypertension. In the present study, we investigated the role of endothelial PHD2 in angiotensin II-mediated arterial stiffness, pericyte recruitment, and cardiac fibrosis.

METHODS AND RESULTS

Chondroitin sulfate proteoglycan 4 tracing reporter chondroitin sulfate proteoglycan 4- red fluorescent protein (DsRed) transgenic mice were crossed with PHD2flox/flox (PHD2f/f) mice and endothelial-specific knockout of PHD2 (PHD2ECKO) mice. Transgenic PHD2f/f (TgPHD2f/f) mice and TgPHD2ECKO mice were infused with angiotensin II for 4 weeks. Arterial thickness, stiffness, and histological and immunofluorescence of pericytes and fibrosis were measured. Infusion of TgPHD2f/f mice with angiotensin II resulted in a time-dependent increase in pulse-wave velocity. Angiotensin II-induced pulse-wave velocity was further elevated in the TgPHD2ECKO mice. TgPHD2ECKO also reduced coronary flow reserve compared with TgPHD2f/f mice infused with angiotensin II. Mechanistically, knockout of endothelial PHD2 promoted aortic arginase activity and angiotensin II-induced aortic thickness together with increased transforming growth factor-β1 and ICAM-1/VCAM-1 expression in coronary arteries. TgPHD2f/f mice infused with angiotensin II for 4 weeks exhibited a significant increase in cardiac fibrosis and hypertrophy, which was further developed in the TgPHD2ECKO mice. Chondroitin sulfate proteoglycan 4 pericyte was traced by DsRed+ staining and angiotensin II infusion displayed a significant increase of DsRed+ pericytes in the heart, as well as a deficiency of endothelial PHD2, which further promoted angiotensin II-induced pericyte increase. DsRed+ pericytes were costained with fibroblast-specific protein 1 and α-smooth muscle actin for measuring pericyte-myofibroblast cell transition. The knockout of endothelial PHD2 increased the amount of DsRed+/fibroblast-specific protein 1+ and DsRed+/α-smooth muscle actin+ cells induced by angiotensin II infusion.

CONCLUSIONS

Knockout of endothelial PHD2 enhanced angiotensin II-induced cardiac fibrosis by mechanisms involving increasing arterial stiffness and pericyte-myofibroblast cell transitions.

Cardiac tissue engineering: an emerging approach to the treatment of heart failure

Heart failure is a major health problem in which the heart is unable to pump enough blood to meet the body's needs. It is a progressive disease that becomes more severe over time and can be caused by a variety of factors, including heart attack, cardiomyopathy and heart valve disease. There are various methods to cure this disease, which has many complications and risks. The advancement of knowledge and technology has proposed new methods for many diseases. One of the promising new treatments for heart failure is tissue engineering. Tissue engineering is a field of research that aims to create living tissues and organs to replace damaged or diseased tissue. The goal of tissue engineering in heart failure is to improve cardiac function and reduce the need for heart transplantation. This can be done using the three important principles of cells, biomaterials and signals to improve function or replace heart tissue. The techniques for using cells and biomaterials such as electrospinning, hydrogel synthesis, decellularization, etc. are diverse. Treating heart failure through tissue engineering is still under development and research, but it is hoped that there will be no transplants or invasive surgeries in the near future. In this study, based on the most important research in recent years, we will examine the power of tissue engineering in the treatment of heart failure.

The fate and role of the pericytes in myocardial diseases

The adult mammalian heart contains a large population of pericytes that play important roles in homeostasis and disease. In the normal heart, pericytes regulate microvascular permeability and flow. Myocardial diseases are associated with marked alterations in pericyte phenotype and function. This review manuscript discusses the role of pericytes in cardiac homeostasis and disease. Following myocardial infarction (MI), cardiac pericytes participate in all phases of cardiac repair. During the inflammatory phase, pericytes may secrete cytokines and chemokines and may regulate leukocyte trafficking, through formation of intercellular gaps that serve as exit points for inflammatory cells. Moreover, pericyte contraction induces microvascular constriction, contributing to the pathogenesis of 'no-reflow' in ischemia and reperfusion. During the proliferative phase, pericytes are activated by growth factors, such as transforming growth factor (TGF)-β and contribute to fibrosis, predominantly through secretion of fibrogenic mediators. A fraction of pericytes acquires fibroblast identity but contributes only to a small percentage of infarct fibroblasts and myofibroblasts. As the scar matures, pericytes form a coat around infarct neovessels, promoting stabilization of the vasculature. Pericytes may also be involved in the pathogenesis of chronic heart failure, by regulating inflammation, fibrosis, angiogenesis and myocardial perfusion. Pericytes are also important targets of viral infections (such as SARS-CoV2) and may be implicated in the pathogenesis of cardiac complications of COVID19. Considering their role in myocardial inflammation, fibrosis and angiogenesis, pericytes may be promising therapeutic targets in myocardial disease.

Repair of the Infarcted Heart: Cellular Effectors, Molecular Mechanisms and Therapeutic Opportunities

The adult mammalian heart has limited endogenous regenerative capacity and heals through the activation of inflammatory and fibrogenic cascades that ultimately result in the formation of a scar. After infarction, massive cardiomyocyte death releases a broad range of damage-associated molecular patterns that initiate both myocardial and systemic inflammatory responses. TLRs (toll-like receptors) and NLRs (NOD-like receptors) recognize damage-associated molecular patterns (DAMPs) and transduce downstream proinflammatory signals, leading to upregulation of cytokines (such as interleukin-1, TNF-α [tumor necrosis factor-α], and interleukin-6) and chemokines (such as CCL2 [CC chemokine ligand 2]) and recruitment of neutrophils, monocytes, and lymphocytes. Expansion and diversification of cardiac macrophages in the infarcted heart play a major role in the clearance of the infarct from dead cells and the subsequent stimulation of reparative pathways. Efferocytosis triggers the induction and release of anti-inflammatory mediators that restrain the inflammatory reaction and set the stage for the activation of reparative fibroblasts and vascular cells. Growth factor-mediated pathways, neurohumoral cascades, and matricellular proteins deposited in the provisional matrix stimulate fibroblast activation and proliferation and myofibroblast conversion. Deposition of a well-organized collagen-based extracellular matrix network protects the heart from catastrophic rupture and attenuates ventricular dilation. Scar maturation requires stimulation of endogenous signals that inhibit fibroblast activity and prevent excessive fibrosis. Moreover, in the mature scar, infarct neovessels acquire a mural cell coat that contributes to the stabilization of the microvascular network. Excessive, prolonged, or dysregulated inflammatory or fibrogenic cascades accentuate adverse remodeling and dysfunction. Moreover, inflammatory leukocytes and fibroblasts can contribute to arrhythmogenesis. Inflammatory and fibrogenic pathways may be promising therapeutic targets to attenuate heart failure progression and inhibit arrhythmia generation in patients surviving myocardial infarction.

Cardiac and perivascular myofibroblasts, matrifibrocytes, and immune fibrocytes in hypertension; commonalities and differences with other cardiovascular diseases

Hypertension is a major cause of cardiovascular diseases such as myocardial infarction and stroke. Cardiovascular fibrosis occurs with hypertension and contributes to vascular resistance, aortic stiffness, and cardiac hypertrophy. However, the molecular mechanisms leading to fibroblast activation in hypertension remain largely unknown. There are two types of fibrosis: replacement fibrosis and reactive fibrosis. Replacement fibrosis occurs in response to the loss of viable tissue to form a scar. Reactive fibrosis occurs in response to an increase in mechanical and neurohormonal stress. Although both types of fibrosis are considered adaptive processes, they become maladaptive when the tissue loss is too large, or the stress persists. Myofibroblasts represent a subpopulation of activated fibroblasts that have gained contractile function to promote wound healing. Therefore, myofibroblasts are a critical cell type that promotes replacement fibrosis. Although myofibroblasts were recognized as the fibroblasts participating in reactive fibrosis, recent experimental evidence indicated there are distinct fibroblast populations in cardiovascular reactive fibrosis. Accordingly, we will discuss the updated definition of fibroblast subpopulations, the regulatory mechanisms, and their potential roles in cardiovascular pathophysiology utilizing new knowledge from various lineage tracing and single-cell RNA sequencing studies. Among the fibroblast subpopulations, we will highlight the novel roles of matrifibrocytes and immune fibrocytes in cardiovascular fibrosis including experimental models of hypertension, pressure overload, myocardial infarction, atherosclerosis, aortic aneurysm, and nephrosclerosis. Exploration into the molecular mechanisms involved in the differentiation and activation of those fibroblast subpopulations may lead to novel treatments for end-organ damage associated with hypertension and other cardiovascular diseases.

Cardiac fibrogenesis: an immuno-metabolic perspective

Cardiac fibrosis is a major and complex pathophysiological process that ultimately culminates in cardiac dysfunction and heart failure. This phenomenon includes not only the replacement of the damaged tissue by a fibrotic scar produced by activated fibroblasts/myofibroblasts but also a spatiotemporal alteration of the structural, biochemical, and biomechanical parameters in the ventricular wall, eliciting a reactive remodeling process. Though mechanical stress, post-infarct homeostatic imbalances, and neurohormonal activation are classically attributed to cardiac fibrosis, emerging evidence that supports the roles of immune system modulation, inflammation, and metabolic dysregulation in the initiation and progression of cardiac fibrogenesis has been reported. Adaptive changes, immune cell phenoconversions, and metabolic shifts in the cardiac nonmyocyte population provide initial protection, but persistent altered metabolic demand eventually contributes to adverse remodeling of the heart. Altered energy metabolism, mitochondrial dysfunction, various immune cells, immune mediators, and cross-talks between the immune cells and cardiomyocytes play crucial roles in orchestrating the transdifferentiation of fibroblasts and ensuing fibrotic remodeling of the heart. Manipulation of the metabolic plasticity, fibroblast-myofibroblast transition, and modulation of the immune response may hold promise for favorably modulating the fibrotic response following different cardiovascular pathological processes. Although the immunologic and metabolic perspectives of fibrosis in the heart are being reported in the literature, they lack a comprehensive sketch bridging these two arenas and illustrating the synchrony between them. This review aims to provide a comprehensive overview of the intricate relationship between different cardiac immune cells and metabolic pathways as well as summarizes the current understanding of the involvement of immune-metabolic pathways in cardiac fibrosis and attempts to identify some of the previously unaddressed questions that require further investigation. Moreover, the potential therapeutic strategies and emerging pharmacological interventions, including immune and metabolic modulators, that show promise in preventing or attenuating cardiac fibrosis and restoring cardiac function will be discussed.

Myocardial ischemia/reperfusion: Translational pathophysiology of ischemic heart disease

Ischemic heart disease is the greatest health burden and most frequent cause of death worldwide. Myocardial ischemia/reperfusion is the pathophysiological substrate of ischemic heart disease. Improvements in prevention and treatment of ischemic heart disease have reduced mortality in developed countries over the last decades, but further progress is now stagnant, and morbidity and mortality from ischemic heart disease in developing countries are increasing. Significant problems remain to be resolved and require a better pathophysiological understanding. The present review attempts to briefly summarize the state of the art in myocardial ischemia/reperfusion research, with a view on both its coronary vascular and myocardial aspects, and to define the cutting edges where further mechanistic knowledge is needed to facilitate translation to clinical practice.

Effects of scutellarin on the mechanism of cardiovascular diseases: a review

Cardiovascular diseases represent a significant worldwide problem, jeopardizing individuals' physical and mental wellbeing as well as their quality of life as a result of their widespread incidence and fatality. With the aging society, the occurrence of Cardiovascular diseases is progressively rising each year. However, although drugs developed for treating Cardiovascular diseases have clear targets and proven efficacy, they still carry certain toxic and side effect risks. Therefore, finding safe, effective, and practical treatment options is crucial. Scutellarin is the primary constituent of Erigeron breviscapus (Vant.) Hand-Mazz. This article aims to establish a theoretical foundation for the creation and use of secure, productive, and logical medications for Scutellarin in curing heart-related illnesses. Additionally, the examination and analysis of the signal pathway and its associated mechanisms with regard to the employment of SCU in treating heart diseases will impart innovative resolving concepts for the treatment and prevention of Cardiovascular diseases.

TGF-β as a therapeutic target in the infarcted and failing heart: cellular mechanisms, challenges, and opportunities

INTRODUCTION

Myocardial fibrosis accompanies most cardiac conditions and can be reparative or maladaptive. Transforming Growth Factor (TGF)-β is a potent fibrogenic mediator, involved in repair, remodeling, and fibrosis of the injured heart.

AREAS COVERED

This review manuscript discusses the role of TGF-β in heart failure focusing on cellular mechanisms and therapeutic implications. TGF-β is activated in infarcted, remodeling and failing hearts. In addition to its fibrogenic actions, TGF-β has a broad range of effects on cardiomyocytes, immune, and vascular cells that may have both protective and detrimental consequences. TGF-β-mediated effects on macrophages promote anti-inflammatory transition, whereas actions on fibroblasts mediate reparative scar formation and effects on pericytes are involved in maturation of infarct neovessels. On the other hand, TGF-β actions on cardiomyocytes promote adverse remodeling, and prolonged activation of TGF-β signaling in fibroblasts stimulates progression of fibrosis and heart failure.

EXPERT OPINION

Understanding of the cell-specific actions of TGF-β is necessary to design therapeutic strategies in patients with myocardial disease. Moreover, to implement therapeutic interventions in the heterogeneous population of heart failure patients, mechanism-driven classification of both HFrEF and HFpEF patients is needed. Heart failure patients with prolonged or overactive fibrogenic TGF-β responses may benefit from cautious TGF-β inhibition.

Spatiotemporal signaling underlies progressive vascular rarefaction in myocardial infarction

Therapeutic angiogenesis represents a promising avenue to revascularize the ischemic heart. Its limited success is partly due to our poor understanding of the cardiac stroma, specifically mural cells, and their response to ischemic injury. Here, we combine single-cell and positional transcriptomics to assess the behavior of mural cells within the healing heart. In response to myocardial infarction, mural cells adopt an altered state closely associated with the infarct and retain a distinct lineage from fibroblasts. This response is concurrent with vascular rarefaction and reduced vascular coverage by mural cells. Positional transcriptomics reveals that the infarcted heart is governed by regional-dependent and temporally regulated programs. While the remote zone acts as an important source of pro-angiogenic signals, the infarct zone is accentuated by chronic activation of anti-angiogenic, pro-fibrotic, and inflammatory cues. Together, our work unveils the spatiotemporal programs underlying cardiac repair and establishes an association between vascular deterioration and mural cell dysfunction.

Protocatechuic aldehyde increases pericyte coverage and mitigates pericyte damage to enhance the atherosclerotic plaque stability

Pericyte dysfunction and loss contribute substantially to the destabilization and rupture of atherosclerotic plaques. Protocatechuic aldehyde (PCAD), a natural polyphenol, exerts anti-atherosclerotic effects. However, the effects and mechanisms of this polyphenol on pericyte recruitment, coverage, and pericyte function remain unknown. We here treated apolipoprotein E-deficient mice having high-fat diet-induced atherosclerosis with PCAD. PCAD achieved therapeutic effects similar to rosuvastatin in lowering lipid levels and thus preventing atherosclerosis progression. With PCAD administration, plaque phenotype exhibited higher stability with markedly reduced lesion vulnerability, which is characterized by reduced lipid content and macrophage accumulation, and a consequent increase in collagen deposition. PCAD therapy increased pericyte coverage in the plaques, reduced VEGF-A production, and inhibited intraplaque neovascularization. PCAD promoted pericyte proliferation, adhesion, and migration to mitigate ox-LDL-induced pericyte dysfunction, which thus maintained the capillary network structure and stability. Furthermore, TGFBR1 silencing partially reversed the protective effect exerted by PCAD on human microvascular pericytes. PCAD increased pericyte coverage and impeded ox-LDL-induced damages through TGF-β1/TGFBR1/Smad2/3 signaling. All these novel findings indicated that PCAD increases pericyte coverage and alleviates pericyte damage to improve the stability of atherosclerotic plaques, which is accomplished by regulating TGF-β1/TGFBR1/Smad2/3 signaling in pericytes.

Role of Pericytes in Cardiomyopathy-Associated Myocardial Infarction Revealed by Multiple Single-Cell Sequencing Analysis

Acute myocardial infarction (AMI) is one of the leading causes of cardiovascular death worldwide. AMI with cardiomyopathy is accompanied by a poor long-term prognosis. However, limited studies have focused on the mechanism of cardiomyopathy associated with AMI. Pericytes are important to the microvascular function in the heart, yet little attention has been paid to their function in myocardial infarction until now. In this study, we integrated single-cell data from individuals with cardiomyopathy and myocardial infarction (MI) GWAS data to reveal the potential function of pericytes in cardiomyopathy-associated MI. We found that pericytes were concentrated in the left atrium and left ventricle tissues. DLC1/GUCY1A2/EGFLAM were the top three uniquely expressed genes in pericytes (p < 0.05). The marker genes of pericytes were enriched in renin secretion, vascular smooth muscle contraction, gap junction, purine metabolism, and diabetic cardiomyopathy pathways (p < 0.05). Among these pathways, the renin secretion and purine metabolism pathways were also found in the process of MI. In cardiomyopathy patients, the biosynthesis of collagen, modulating enzymes, and collagen formation were uniquely negatively regulated in pericytes compared to other cell types (p < 0.05). COL4A2/COL4A1/SMAD3 were the hub genes in pericyte function involved in cardiomyopathy and AMI. In conclusion, this study provides new evidence about the importance of pericytes in the pathogenesis of cardiomyopathy-associated MI. DLC1/GUCY1A2/EGFLAM were highly expressed in pericytes. The hub genes COL4A2/COL4A1/SMAD3 may be potential research targets for cardiomyopathy-associated MI.