Pathological hypertrophy and cardiac interstitium. Fibrosis and renin-angiotensin-aldosterone system

Autophagy in cardiac pathophysiology: Navigating the complex roles and therapeutic potential in cardiac fibrosis

Cardiac fibrosis is a critical factor in cardiac structural remodeling and dysfunction, closely associated with the progression of various cardiovascular diseases (CVDs), including heart failure and myocardial infarction (MI). It is characterized by excessive extracellular matrix (ECM) deposition, which disrupts normal cardiac architecture and impairs cardiac function. Autophagy, a cellular degradation and recycling mechanism, is essential for maintaining cardiac homeostasis, mitigating stress responses, and preventing cellular damage. Recent studies have revealed a significant link between autophagy and cardiac fibrosis, suggesting that autophagic dysregulation can exacerbate fibrosis by promoting fibroblast activation and ECM accumulation. Conversely, proper autophagic activity may attenuate cardiac fibrosis by removing damaged cellular components and regulating fibrotic signaling pathways. This review examines the role of autophagy in cardiac fibrosis. It also emphasizes potential pharmacological strategies that can be used to modulate autophagic processes. These strategies may serve as therapeutic approaches for treating cardiac fibrosis, with the ultimate goal of preventing excessive fibrosis and enhancing cardiac function.

The role of finerenone in heart failure

Heart failure (HF) with mildly reduced or preserved ejection fraction (HFmrEF/HFpEF) represents approximately half of all HF cases, yet therapeutic options are limited. Mineralocorticoid receptor (MR) overactivation by aldosterone has long been recognized as a key driver of vascular inflammation, cardiac fibrosis, and cardiac hypertrophy, pathophysiological processes integral to the development and progression of HFmrEF/HFpEF. The non-steroidal MRA finerenone has been developed with a distinct pharmacological profile: potent and selective MR blockade with a reduced risk of off-target hormone-related side effects. Large, multicenter randomized placebo-controlled trials in chronic kidney disease and type 2 diabetes patients (FIDELIO-DKD, FIGARO-DKD) first highlighted finerenone's cardiorenal benefits, including a reduction in death from cardiovascular causes and hospitalization for HF. More recently, the FINEARTS-HF trial extended this evidence to patients with HFmrEF/HFpEF, demonstrating a significant reduction in the risk of worsening HF events and death from cardiovascular causes. Ongoing studies, such as REDEFINE-HF, CONFIRMATION-HF, and FINALITY-HF, will examine the potential role of finerenone in HF across a broad spectrum of ejection fractions and different clinical settings. This review synthesizes the evolving evidence supporting the role of finerenone as a new option in the management of HF.

The Antifibrotic Effects of Eplerenone in Hypertrophic Cardiomyopathy: A Randomized Clinical Trial

BACKGROUND

Fibrosis plays a central role in hypertrophic cardiomyopathy (HCM), contributing to symptoms via impaired systolic and diastolic function and ventricular arrhythmias.

OBJECTIVES

The aim of this study was to determine if eplerenone has an antifibrotic effect in nonobstructive HCM (resting left ventricular outflow tract gradient <30 mm Hg).

METHODS

This was a randomized, double-blind, placebo-controlled trial of eplerenone in 61 patients with nonobstructive HCM over 12 months. The primary endpoint was native T1 time on cardiac magnetic resonance as an index of diffuse fibrosis. Secondary endpoints included changes in diastolic function.

RESULTS

Thirty patients were randomized to 50 mg eplerenone and 31 to placebo. There was a reduction in native T1 time within the eplerenone group (1,315 ± 134 ms at baseline vs 1,259 ± 92 ms at 12 months; P = 0.041), with no significant change in the placebo group (1,234 ± 28 ms at baseline vs 1,238 ± 70 ms at 12 months; P = 0.854). This represents a 3.7% ± 9% reduction in native T1 with eplerenone compared with a 1.1% ± 9% increase with placebo (P = 0.07). There was no significant change in functional status or markers of diastolic function (such as E/e' ratio or mitral E/A ratio).

CONCLUSIONS

In patients with nonobstructive HCM, there was a reduction in myocardial T1 time with eplerenone, consistent with a reduction in diffuse myocardial fibrosis. Larger and longer trials are needed to confirm this finding and explore whether it translates into improved exercise capacity or a reduction in mortality over time. (Anti-fibrotic role of eplerenone on diffuse myocardial fibrosis and diastolic function in patients with hypertrophic cardiomyopathy; ACTRN12613000065796).

Extracellular volume fraction and native T1 mapping in diabetic cardiomyopathy: a comprehensive meta-analysis

BACKGROUND

Type 2 diabetes mellitus (T2DM) is associated with myocardial fibrosis (MF), a major contributor to adverse cardiovascular outcomes. Cardiovascular magnetic resonance (CMR), specifically extracellular volume fraction (ECV) and native T1 mapping, offers a non-invasive approach to quantify MF. This study aims to evaluate the utility of ECV and native T1 mapping as biomarkers for cardiac fibrosis and to assess their relationship with diabetes severity, measured by hemoglobin A1C (HbA1C), in patients with T2DM.

METHODS

A systematic review and meta-analysis were conducted following PRISMA guidelines. Comprehensive searches identified 19 eligible studies comprising 4,117 participants. Weighted mean differences (WMDs) were calculated for ECV and native T1 values between diabetic and non-diabetic groups. Meta-regression assessed the correlation between ECV and HbA1C. Sensitivity and subgroup analyses were performed to explore heterogeneity.

RESULTS

Diabetic patients exhibited significantly higher ECV values than controls (WMD: 2.17; 95% CI: 1.32-3.02), consistent across subgroups excluding cardiac comorbidities (WMD: 2.02; 95% CI: 0.74-3.31). HbA1C levels were also significantly elevated in diabetics (WMD: 1.78; 95% CI: 1.37-2.19). However, no significant difference in native T1 values was observed (WMD: 13.40; 95% CI: -13.98-40.79). Meta-regression revealed no significant correlation between ECV and HbA1C, potentially due to limited data and high heterogeneity (I²: 93.37%).

CONCLUSIONS

ECV is a promising marker for quantifying MF in T2DM, demonstrating significant differences between diabetics and controls. The lack of correlation between ECV and HbA1C underscores the complexity of MF in diabetes and highlights the need for further research. Future studies with standardized protocols are essential to validate these findings and refine the use of CMR in diabetic cardiomyopathy.

Elevated septal native T1 time in cardiac magnetic resonance imaging suggesting myocardial fibrosis in young kidney transplant recipients

BACKGROUND

Patients after kidney transplantation (KTx) in childhood show a high prevalence of cardiac complications, but the underlying mechanism is still poorly understood. In adults, myocardial fibrosis detected in cardiovascular magnetic resonance (CMR) imaging is already an established risk factor. Data for children after KTx are not available. This study aimed to explore cardiac function and structure with focus on myocardial fibrosis and associated risk factors in KTx recipients.

METHODS

Forty-six KTx recipients (mean age 16.0 ± 3.5 years) and 46 age- and sex-matched healthy controls were examined with non-contrast CMR imaging. Native T1 time (nT1), a marker for myocardial fibrosis, was measured at the interventricular septum. Other parameters comprised left ventricular mass index (LVMI), left ventricular ejection fraction (LVEF), and global longitudinal strain (GLS). Multivariable linear regression analyses were used to explore associations with nT1.

RESULTS

Mean nT1 was significantly higher in KTx recipients compared to controls (1198.1 ± 48.8 vs 1154.4 ± 23.4 ms, p < 0.0001). 46% (21/46) had a nT1 above the upper limit of the normal range (mean + 2 standard deviations of controls). KTx recipients showed higher LVMI z-scores (0.1 ± 1.1 vs -0.3 ± 0.7, p = 0.026), higher LVEF (67.3 ± 3.8% vs 65.3 ± 3.6%, p = 0.012), and lower GLS (-19.0 ± 2.1% vs -20.3 ± 2.7%, p = 0.010). Higher systolic blood pressure (ß = 1.284, p = 0.001), LVMI (ß = 1.542, p < 0.001), and LVEF (ß = 3.535, p = 0.026) were associated with longer nT1 only in KTx recipients, but not in controls. Only 2 KTx recipients exhibited left ventricular hypertrophy; however, a total of 18 displayed elevated nT1 with LVMI z-score within the normal range.

CONCLUSION

Our data suggest the presence of cardiac remodeling with myocardial fibrosis in a significant proportion of young KTx recipients. Non-contrast CMR imaging has the potential to visualize early structural cardiac changes and could become an important diagnostic adjunct in the follow-up of KTx recipients. Longitudinal studies are needed to further evaluate the importance of nT1 in early identification of those at high risk for sudden cardiac death allowing to integrate preventive strategies.

A Vaccine Against Fibroblast Activation Protein Improves Murine Cardiac Fibrosis by Preventing the Accumulation of Myofibroblasts

BACKGROUND

Myofibroblasts are primary cells involved in chronic response-induced cardiac fibrosis. Fibroblast activation protein (FAP) is a relatively specific marker of activated myofibroblasts and a potential target molecule. This study aimed to clarify whether a vaccine targeting FAP could eliminate myofibroblasts in chronic cardiac stress model mice and reduce cardiac fibrosis.

METHODS

We coadministered a FAP peptide vaccine with a cytosine-phosphate-guanine (CpG) K3 oligonucleotide adjuvant to male C57/BL6J mice and confirmed an elevation in the anti-FAP antibody titer. After continuous angiotensin II and phenylephrine administration for 28 days, we evaluated the degree of cardiac fibrosis and the number of myofibroblasts in cardiac tissues.

RESULTS

We found that cardiac fibrosis was significantly decreased in the FAP-vaccinated mice compared with the angiotensin II and phenylephrine control mice (3.45±1.11% versus 8.62±4.79%; P=4.59×10-3) and that the accumulation of FAP-positive cells was also significantly decreased, as indicated by FAP immunohistochemical staining (4077±1746 versus 7327±1741 cells/mm2; FAP vaccine versus angiotensin II and phenylephrine control; P=6.67×10-3). No systemic or organ-specific inflammation due to antibody-dependent cell cytotoxicity induced by the FAP vaccine was observed. Although the transient activation of myofibroblasts has an important role in maintaining the structural robustness in the process of tissue repair, the FAP vaccine showed no adverse effects in myocardial infarction and skin injury models.

CONCLUSIONS

Our study demonstrates the FAP vaccine can be a therapeutic tool for cardiac fibrosis.

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.

Small extracellular vesicles derived from umbilical cord mesenchymal stem cells alleviate radiation-induced cardiac organoid injury

BACKGROUND

Radiation-induced heart disease (RIHD) is one of the most serious complications of radiation therapy (RT) for thoracic tumors, and new interventions are needed for its prevention and treatment. Small extracellular vesicles (sEVs) from stem cells have attracted much attention due to their ability to repair injury. However, the role of umbilical cord mesenchymal stem cell (UCMSC)-derived sEVs in protecting cardiac organoids from radiation-induced injury and the underlying mechanisms are largely unknown.

METHODS

A radiation-induced cardiac organoid injury model was established by using X-ray radiation, and the optimal radiation dose of 20 Gy was determined by live/dead staining. After radiation, the cardiac organoids were treated with sEVs derived from UCMSCs, and energy metabolism, calcium transient changes and the ultrastructure of the organoids were assessed through Seahorse analysis, optical mapping and transmission electron microscopy, respectively. Confocal microscopy was used to observe the changes in mitochondrial ROS and mitochondrial membrane potential (ΔΨm). Furthermore, real-time quantitative PCR was used to verify the RNA-seq results.

RESULTS

After X-ray radiation, the mortality of cardiac organoids significantly increased, energy metabolism decreased, and calcium transients changed. We also observed that the mitochondrial structure of cardiac organoids was disrupted and that ΔΨm was decreased. These effects could be inhibited by sEVs treatment. sEVs may protect against radiation-induced cardiac organoid injury by regulating oxidative phosphorylation and the p53 signaling pathway.

CONCLUSION

sEVs derived from UCMSCs can be used as a potential therapeutic strategy for radiation-induced heart disease.

Molecular and metabolomic characterization of hiPSC-derived cardiac fibroblasts transitioning to myofibroblasts

Background

Mechanical stress and pathological signaling trigger the activation of fibroblasts to myofibroblasts, which impacts extracellular matrix composition, disrupts normal wound healing, and can generate deleterious fibrosis. Myocardial fibrosis independently promotes cardiac arrhythmias, sudden cardiac arrest, and contributes to the severity of heart failure. Fibrosis can also alter cell-to-cell communication and increase myocardial stiffness which eventually may lead to lusitropic and inotropic cardiac dysfunction. Human induced pluripotent stem cell derived cardiac fibroblasts (hiPSC-CFs) have the potential to enhance clinical relevance in precision disease modeling by facilitating the study of patient-specific phenotypes. However, it is unclear whether hiPSC-CFs can be activated to become myofibroblasts akin to primary cells, and the key signaling mechanisms in this process remain unidentified.

Objective

We aim to explore the notable changes in fibroblast phenotype upon passage-mediated activation of hiPSC-CFs with increased mitochondrial metabolism, like primary cardiac fibroblasts.

Methods

We activated the hiPSC-CFs with serial passaging from passage 0 to 3 (P0 to P3) and treatment of P0 with TGFβ1.

Results

Passage-mediated activation of hiPSC-CFs was associated with a gradual induction of genes to initiate the activation of these cells to myofibroblasts, including collagen, periostin, fibronectin, and collagen fiber processing enzymes with concomitant downregulation of cellular proliferation markers. Most importantly, canonical TGFβ1 and Hippo signaling component genes including TAZ were influenced by passaging hiPSC-CFs. Seahorse assay revealed that passaging and TGFβ1 treatment increased mitochondrial respiration, consistent with fibroblast activation requiring increased energy production, whereas treatment with the glutaminolysis inhibitor BPTES completely attenuated this process.

Conclusion

Our study highlights that the hiPSC-CF passaging enhanced fibroblast activation, activated fibrotic signaling pathways, and enhanced mitochondrial metabolism approximating what has been reported in primary cardiac fibroblasts. Thus, hiPSC-CFs may provide an accurate in vitro preclinical model for the cardiac fibrotic condition, which may facilitate the identification of putative anti-fibrotic therapies, including patient-specific approaches.

Dexamethasone in COVID-19 treatment: Analyzing monotherapy and combination therapy approaches

The COVID-19 pandemic has prompted the exploration of effective treatment options, with dexamethasone emerging as a key corticosteroid for severe cases. This review evaluates the efficacy and safety of dexamethasone, highlighting its ability to reduce mortality rates, alleviate acute respiratory distress syndrome (ARDS), and mitigate hyperinflammation. While dexamethasone shows therapeutic promise, potential adverse effects-including cardiovascular issues, neuropsychiatric complications, lung infections, and liver damage-necessitate careful monitoring and individualized treatment strategies. The review also addresses the debate over using dexamethasone alone versus in combination with other therapies targeting SARS-CoV-2, examining potential synergistic effects and drug resistance. In summary, dexamethasone is a valuable treatment option for COVID-19 but its risks highlight the need for tailored surveillance approaches. Further research is essential to establish clear guidelines for optimizing treatment and improving patient outcomes.

Fibroblast Growth Factors in Cardiovascular Disease

Despite advancements in managing traditional cardiovascular risk factors, many cardiovascular diseases (CVDs) persist. Fibroblast growth factors (FGFs) have emerged as potential diagnostic markers and therapeutic targets for CVDs. FGF1, FGF2, and FGF4 are primarily used for therapeutic angiogenesis. Clinical applications are being explored based on animal studies using approaches such as recombinant protein administration and adenovirus-mediated gene delivery, targeting patients with coronary artery disease and lower extremity arterial disease. Although promising results have been observed in animal models and early-stage clinical trials, further studies are required to assess their therapeutic potential. The FGF19 subfamily, consisting of FGF19, FGF21, and FGF23, act via endocrine signaling in various organs. FGF19, primarily expressed in the small intestine, plays important roles in glucose, lipid, and bile acid metabolism and has therapeutic potential for metabolic disorders. FGF21, found in various tissues, improves glucose metabolism and insulin sensitivity, suggesting potential for treating obesity and diabetes. FGF23, primarily secreted by osteocytes, regulates vitamin D and phosphate metabolism and serves as an important biomarker for chronic kidney disease and CVDs. Thus, FGFs holds promise for both therapeutic and diagnostic applications in metabolic and cardiovascular diseases. Understanding the mechanisms of FGF may pave the way for novel strategies to prevent and manage CVDs, potentially addressing the limitations of current treatments. This review explores the roles of FGF1, FGF2, FGF4, and the FGF19 subfamily in maintaining cardiovascular health. Further research and clinical trials are crucial to fully understand the therapeutic potential of FGFs in managing cardiovascular health.

Multimodality imaging for the global evaluation of aortic stenosis: The valve, the ventricle, the afterload

Aortic stenosis (AS) is the most common valvular heart disease growing in parallel to the increment of life expectancy. Besides the valve, the degenerative process affects the aorta, impairing its elastic properties and leading to increased systemic resistance. The composite of valvular and systemic afterload mediates ventricular damage. The first step of a thorough evaluation of AS should include a detailed assessment of valvular anatomy and hemodynamics. Subsequently, the ventricle, and the global afterload should be assessed to define disease stage and prognosis. Multimodality imaging is of paramount importance for the comprehensive evaluation of these three elements. Echocardiography is the cornerstone modality whereas Multi-Detector Computed Tomography and Cardiac Magnetic Resonance provide useful complementary information. This review comprehensively examines the merits of these imaging modalities in AS for the evaluation of the valve, the ventricle, and the afterload and ultimately endeavors to integrate them in a holistic assessment of AS.

Left ventricular diastolic dysfunction in patients with heart failure with mildly reduced ejection fraction

OBJECTIVE

This study investigates the prevalence and prognostic impact of diastolic dysfunction (DD) in patients hospitalized with heart failure (HF) with mildly reduced ejection fraction (HFmrEF) in sinus rhythm.

BACKGROUND

Data regarding the prognostic impact of DD in patients with HFmrEF is limited.

METHODS

From 2016 to 2022, all patients hospitalized with HFmrEF (i.e., left ventricular ejection fraction 41-49% and signs and/or symptoms of HF) were retrospectively included at one institution. Patients with DD were compared to patients without (i.e., non-DD), further risk stratification was performed according to the severity of DD. The primary endpoint was all-cause mortality at 30 months (interquartile range (IQR) 15-61 months), key secondary endpoint was rehospitalization for worsening HF.

RESULTS

From a total of 1154 patients (median age 68 years, 68% males) hospitalized with HFmrEF, concomitant DD was present in 72% (grade I: 56%, grade II: 14%, grade III: 2%). Patients with DD were older (71 years vs. 65 years; p = 0.001) and presented with higher rates of cardiovascular comorbidities. The presence of DD was not associated with the risk of long-term all-cause mortality (adjusted HR = 0.815; 95% CI 0.612-1.085; p = 0.161) or HF-related rehospitalization (adjusted HR = 0.736; 95% CI 0.442-1.225; p = 0.238). Furthermore, the outcome did not differ in patients with more advanced stages of DD.

CONCLUSION

DD is commonly prevalent in patients with HFmrEF, but not associated with long-term prognosis.

Diastolic dysfunction in hypertension: a comprehensive review of pathophysiology, diagnosis, and treatment

Diastolic dysfunction refers to impaired relaxation or filling of the ventricles during the diastolic phase of the cardiac cycle. Left ventricular diastolic dysfunction (LVDD) is common in hypertensive individuals and is associated with increased morbidity and mortality. LVDD serves as a critical precursor to heart failure, particularly heart failure with preserved ejection fraction. The pathophysiology of LVDD in hypertension is complex, involving alterations in cardiac structure and function, neurohormonal activation, and vascular stiffness. While the diagnosis of LVDD relies primarily on echocardiography, management remains challenging due to a lack of specific treatment guidelines for LVDD. This review offers an overview of the pathophysiological mechanisms underlying LVDD in hypertension, diagnostic methods, clinical manifestations, strategies for managing LVDD, and prospects for future research.

Imaging of Cardiac Fibrosis: An Update, From the AJR Special Series on Imaging of Fibrosis

Myocardial fibrosis (MF) is defined as excessive production and deposition of extra-cellular matrix proteins that result in pathologic myocardial remodeling. Three types of MF have been identified: replacement fibrosis from tissue necrosis, reactive fibrosis from myocardial stress, and infiltrative interstitial fibrosis from progressive deposition of nondegradable material such as amyloid. Although echocardiography, nuclear medicine, and CT play important roles in the assessment of MF, MRI is pivotal in the evaluation of MF, with the late gadolinium enhancement (LGE) technique used as a primary end point. The LGE technique focuses on the pattern and distribution of gadolinium accumulation in the myocardium and assists in the diagnosis and establishment of the cause of both ischemic and nonischemic cardiomyopathy. LGE MRI also aids prognostication and risk stratification. In addition, LGE MRI is used to guide the management of patients considered for ablation for arrhythmias. Parametric mapping techniques, including T1 mapping and extracellular volume measurement, allow detection and quantification of diffuse fibrosis, which may not be detected by LGE MRI. These techniques also allow monitoring of disease progression and therapy response. This review provides an update on the imaging of MF, including prognostication and risk stratification tools, electrophysiologic considerations, and disease monitoring.

Role of Vasoactive Hormone-Induced Signal Transduction in Cardiac Hypertrophy and Heart Failure

Heart failure is the common concluding pathway for a majority of cardiovascular diseases and is associated with cardiac dysfunction. Since heart failure is invariably preceded by adaptive or maladaptive cardiac hypertrophy, several biochemical mechanisms have been proposed to explain the development of cardiac hypertrophy and progression to heart failure. One of these includes the activation of different neuroendocrine systems for elevating the circulating levels of different vasoactive hormones such as catecholamines, angiotensin II, vasopressin, serotonin and endothelins. All these hormones are released in the circulation and stimulate different signal transduction systems by acting on their respective receptors on the cell membrane to promote protein synthesis in cardiomyocytes and induce cardiac hypertrophy. The elevated levels of these vasoactive hormones induce hemodynamic overload, increase ventricular wall tension, increase protein synthesis and the occurrence of cardiac remodeling. In addition, there occurs an increase in proinflammatory cytokines and collagen synthesis for the induction of myocardial fibrosis and the transition of adaptive to maladaptive hypertrophy. The prolonged exposure of the hypertrophied heart to these vasoactive hormones has been reported to result in the oxidation of catecholamines and serotonin via monoamine oxidase as well as the activation of NADPH oxidase via angiotensin II and endothelins to promote oxidative stress. The development of oxidative stress produces subcellular defects, Ca2+-handling abnormalities, mitochondrial Ca2+-overload and cardiac dysfunction by activating different proteases and depressing cardiac gene expression, in addition to destabilizing the extracellular matrix upon activating some metalloproteinases. These observations support the view that elevated levels of various vasoactive hormones, by producing hemodynamic overload and activating their respective receptor-mediated signal transduction mechanisms, induce cardiac hypertrophy. Furthermore, the occurrence of oxidative stress due to the prolonged exposure of the hypertrophied heart to these hormones plays a critical role in the progression of heart failure.

Combination of ADAM17 knockdown with eplerenone is more effective than single therapy in ameliorating diabetic cardiomyopathy

Background

The renin-angiotensin-aldosterone system (RAAS) members, especially Ang II and aldosterone, play key roles in the pathogenesis of diabetic cardiomyopathy (DCM). Angiotensin-converting enzyme inhibitors or angiotensin-receptor blockers combined with aldosterone receptor antagonists (mineralocorticoid receptor antagonists) have substantially improved clinical outcomes in patients with DCM. However, the use of the combination has been limited due to its high risk of inducing hyperkalemia.

Methods

Type 1 diabetes was induced in 8-week-old male C57BL/6J mice by intraperitoneal injection of streptozotocin at a dose of 55 mg/kg for 5 consecutive days. Adeno-associated virus 9-mediated short-hairpin RNA (shRNA) was used to knock down the expression of ADAM17 in mice hearts. Eplerenone was administered via gavage at 200 mg/kg daily for 4 weeks. Primary cardiac fibroblasts were exposed to high glucose (HG) in vitro for 24 h to examine the cardiac fibroblasts to myofibroblasts transformation (CMT).

Results

Cardiac collagen deposition and CMT increased in diabetic mice, leading to cardiac fibrosis and dysfunction. In addition, ADAM17 expression and activity increased in the hearts of diabetic mice. ADAM17 inhibition and eplerenone treatment both improved diabetes-induced cardiac fibrosis, cardiac hypertrophy and cardiac dysfunction, ADAM17 deficiency combined with eplerenone further reduced the effects of cardiac fibrosis, cardiac hypertrophy and cardiac dysfunction compared with single therapy in vivo. High-glucose stimulation promotes CMT in vitro and leads to increased ADAM17 expression and activity. ADAM17 knockdown and eplerenone pretreatment can reduce the CMT of fibroblasts that is induced by high glucose levels by inhibiting TGFβ1/Smad3 activation; the combination of the two can further reduce CMT compared with single therapy in vitro.

Conclusion

Our findings indicated that ADAM17 knockout could improve diabetes-induced cardiac dysfunction and remodeling through the inhibition of RAAS overactivation when combined with eplerenone treatment, which reduced TGF-β1/Smad3 pathway activation-mediated CMT. The combined intervention of ADAM17 deficiency and eplerenone therapy provided additional cardiac protection compared with a single therapy alone without disturbing potassium level. Therefore, the combination of ADAM17 inhibition and eplerenone is a potential therapeutic strategy for human DCM.

The role of cardiac microenvironment in cardiovascular diseases: implications for therapy

Due to aging populations and changes in lifestyle, cardiovascular diseases including cardiomyopathy, hypertension, and atherosclerosis, are the leading causes of death worldwide. The heart is a complicated organ composed of multicellular types, including cardiomyocytes, fibroblasts, endothelial cells, vascular smooth muscle cells, and immune cells. Cellular specialization and complex interplay between different cell types are crucial for the cardiac tissue homeostasis and coordinated function of the heart. Mounting studies have demonstrated that dysfunctional cells and disordered cardiac microenvironment are closely associated with the pathogenesis of various cardiovascular diseases. In this paper, we discuss the composition and the homeostasis of cardiac tissues, and focus on the role of cardiac environment and underlying molecular mechanisms in various cardiovascular diseases. Besides, we elucidate the novel treatment for cardiovascular diseases, including stem cell therapy and targeted therapy. Clarification of these issues may provide novel insights into the prevention and potential targets for cardiovascular diseases.

Roles of Integrin in Cardiovascular Diseases: From Basic Research to Clinical Implications

Cardiovascular diseases (CVDs) pose a significant global health threat due to their complex pathogenesis and high incidence, imposing a substantial burden on global healthcare systems. Integrins, a group of heterodimers consisting of α and β subunits that are located on the cell membrane, have emerged as key players in mediating the occurrence and progression of CVDs by regulating the physiological activities of endothelial cells, vascular smooth muscle cells, platelets, fibroblasts, cardiomyocytes, and various immune cells. The crucial role of integrins in the progression of CVDs has valuable implications for targeted therapies. In this context, the development and application of various integrin antibodies and antagonists have been explored for antiplatelet therapy and anti-inflammatory-mediated tissue damage. Additionally, the rise of nanomedicine has enhanced the specificity and bioavailability of precision therapy targeting integrins. Nevertheless, the complexity of the pathogenesis of CVDs presents tremendous challenges for monoclonal targeted treatment. This paper reviews the mechanisms of integrins in the development of atherosclerosis, cardiac fibrosis, hypertension, and arrhythmias, which may pave the way for future innovations in the diagnosis and treatment of CVDs.

Aldosterone levels do not predict 28-day mortality in patients treated for COVID-19 in the intensive care unit

The immunotropic effects of aldosterone might play a role in COVID-19, as SARS-CoV-2 reportedly uses angiotensin-converting enzyme 2 receptors as an entry point into cells. Aldosterone function is closely linked to its action on mineralocorticoid receptors in kidneys; it increases the renal retention of sodium and the excretion of potassium, which increases blood pressure. Despite the large number of studies examining the effect of Ang-II and its blockers on the course of COVID-19 infection, there is still uncertainty about the role of aldosterone. The aim of the study was to assess the correlation of aldosterone, urea, creatinine, C-reactive protein (CRP), and procalcitonin (PCT) levels with 28 days of mortality in patients treated for COVID19 in an intensive care unit (ICU). This cross-selection study involved 115 adult patients who were divided into two groups: those who died within a 28-day period (n = 82) and those who survived (n = 33). The correlation of aldosterone, urea, creatinine, C-reactive protein (CRP), and procalcitonin (PCT) levels with 28 days of mortality in patients treated for COVID-19 were performed. The patients' age, sex, scores from the APACHE II, SAPS II, and SOFA scales and comorbidities like HA, IHD and DM were also analyzed. Remarkably, the individuals who survived for 28 days were of significantly lower mean age and achieved notably lower scores on the APACHE II, SAPS II, and SOFA assessment scales. Statistically significantly higher CRP levels were observed on days 3, 5, and 7 in individuals who survived for 28 days. Creatinine levels in the same group were also statistically significantly lower on days 1, 3, and 5 than those of individuals who died within 28 days. The investigation employed both univariate and multivariate Cox proportional hazard regression models to explore factors related to mortality. In the univariate analysis, variables with a p value of less than 0.50 were included in the multivariate model. Age, APACHE II, SAPS II, and SOFA demonstrated significance in univariate analysis and were considered to be associated with mortality. The outcomes of the multivariate analysis indicated that age (HR = 1.03, p = 0.033) served as a robust predictor of mortality in the entire study population. In conclusion the plasma aldosterone level is not associated with ICU mortality in patients with COVID-19. Other factors, including the patient's age, creatinine or CRP contribute to the severity and prognosis of the disease. This study was retrospectively registered in the Australian New Zealand Clinical Trials Registry (ANZCTR) with registration no. ACTRN12621001300864 (27/09/2021: https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=382563&isReview=true ).

Point-of-care diagnosis of tissue fibrosis: a review of advances in vibrational spectroscopy with machine learning

Histopathology is the gold standard for diagnosing fibrosis, but its routine use is constrained by the need for additional stains, time, personnel and resources. Vibrational spectroscopy is a novel technique that offers an alternative atraumatic approach, with short scan times, while providing metabolic and morphological data. This review evaluates vibrational spectroscopy for the assessment of fibrosis, with a focus on point-of-care capabilities. OVID Medline, Embase and Cochrane databases were systematically searched using PRISMA guidelines for search terms including vibrational spectroscopy, human tissue and fibrosis. Studies were stratified based on imaging modality and tissue type. Outcomes recorded included tissue type, machine learning technique, metrics for accuracy and author conclusions. Systematic review yielded 420 articles, of which 14 were relevant. Ten of these articles considered mid-infrared spectroscopy, three dealt with Raman spectroscopy and one with near-infrared spectroscopy. The metrics for detecting fibrosis were Pearson correlation coefficients ranging from 0.65-0.98; sensitivity from 76-100%; specificity from 90-99%; area under receiver operator curves from 0.83-0.98; and accuracy of 86-99%. Vibrational spectroscopy identified fibrosis in myeloproliferative neoplasms in bone, cirrhotic and hepatocellular carcinoma in liver, end-stage heart failure in cardiac tissue and following laser ablation for acne in skin. It also identified interstitial fibrosis as a predictor of early renal transplant rejection in renal tissue. Vibrational spectroscopic techniques can therefore accurately identify fibrosis in a range of human tissues. Emerging data show that it can be used to quantify, classify and provide data about the nature of fibrosis with a high degree of accuracy with potential scope for point-of-care use.

Pterostilbene: a potential therapeutic agent for fibrotic diseases

Fibrosis is a prevailing pathology in chronic diseases and accounts for 45% of deaths in developed countries. This condition is primarily identified by the transformation of fibroblasts into myofibroblasts and the overproduction of extracellular matrix (ECM) by myofibroblasts. Pterostilbene (PTS) is a natural analogue of resveratrol and is most commonly found in blueberries. Research has shown that PTS exerts a wide range of pharmacological effects, such as antioxidant, anti-inflammatory, and anticancer effects. As a result, PTS has the potential to prevent and cure numerous diseases. Emerging evidence has indicated that PTS can alleviate myocardial fibrosis, renal fibrosis, pulmonary fibrosis, hepatic fibrosis, and colon fibrosis via the inhibition of inflammation, oxidative stress, and fibrogenesis effects in vivo and in vitro, and the potential mechanisms are linked to various pathways, including transforming growth factor-β1 (TGF-β1)/small mother against decapentaplegic proteins (Smads) signalling, the reactive oxygen species (ROS)-driven Pitx2c/mir-15b pathway, nuclear factor kappa B (NF-κB) signalling, Kelch-like epichlorohydrin-associated protein-1 (Keap-1)/NF-E2-related factor-2 (Nrf2) cascade, the NLR family pyridine structure domain 3 (NLRP3) pathway, the Janus kinase-2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) pathway, and the Src/STAT3 pathway. In this review, we comprehensively summarize the antifibrotic effects of PTS both in vivo and in vitro and the pharmacological mechanisms, pharmacokinetics, and toxicology of PTS and provide insights into and strategies for exploring promising agents for the treatment of fibrosis.

Potential of Plant-Derived Compounds in Preventing and Reversing Organ Fibrosis and the Underlying Mechanisms

Increased production of extracellular matrix is a necessary response to tissue damage and stress. In a normal healing process, the increase in extracellular matrix is transient. In some instances; however, the increase in extracellular matrix can persist as fibrosis, leading to deleterious alterations in organ structure, biomechanical properties, and function. Indeed, fibrosis is now appreciated to be an important cause of mortality and morbidity. Extensive research has illustrated that fibrosis can be slowed, arrested or even reversed; however, few drugs have been approved specifically for anti-fibrotic treatment. This is in part due to the complex pathways responsible for fibrogenesis and the undesirable side effects of drugs targeting these pathways. Natural products have been utilized for thousands of years as a major component of traditional medicine and currently account for almost one-third of drugs used clinically worldwide. A variety of plant-derived compounds have been demonstrated to have preventative or even reversal effects on fibrosis. This review will discuss the effects and the underlying mechanisms of some of the major plant-derived compounds that have been identified to impact fibrosis.

Anti-Arrhythmic Effects of Heart Failure Guideline-Directed Medical Therapy and Their Role in the Prevention of Sudden Cardiac Death: From Beta-Blockers to Sodium-Glucose Cotransporter 2 Inhibitors and Beyond

Sudden cardiac death (SCD) accounts for a substantial proportion of mortality in heart failure with reduced ejection fraction (HFrEF), frequently triggered by ventricular arrhythmias (VA). This review aims to analyze the pathophysiological mechanisms underlying VA and SCD in HFrEF and evaluate the effectiveness of guideline-directed medical therapy (GDMT) in reducing SCD. Beta-blockers, angiotensin receptor-neprilysin inhibitors, and mineralocorticoid receptor antagonists have shown significant efficacy in reducing SCD risk. While angiotensin-converting enzyme inhibitors and angiotensin receptor blockers exert beneficial impacts on the renin-angiotensin-aldosterone system, their direct role in SCD prevention remains less clear. Emerging treatments like sodium-glucose cotransporter 2 inhibitors show promise but necessitate further research for conclusive evidence. The favorable outcomes of those molecules on VA are notably attributable to sympathetic nervous system modulation, structural remodeling attenuation, and ion channel stabilization. A multidimensional pharmacological approach targeting those pathophysiological mechanisms offers a complete and synergy approach to reducing SCD risk, thereby highlighting the importance of optimizing GDMT for HFrEF. The current landscape of HFrEF pharmacotherapy is evolving, with ongoing research needed to clarify the full extent of the anti-arrhythmic benefits offered by both existing and new treatments.

Serum fibroblast growth factor-2 levels complement vital biomarkers for diagnosing heart failure

BACKGROUND

Early diagnosis of atrial fibrillation is important as it is crucial for improving patient outcomes. Fibroblast growth factor-2 (FGF2) may serve as a diagnostic biomarker for heart failure due to its ability to promote cardiac fibrosis and hypertrophy; however, the relationship between FGF2 concentration and heart failure is unclear. Therefore, this study aimed to explore whether FGF2 could aid in distinguishing patients with heart failure from healthy controls and those with dyspnea without heart failure. Additionally, to evaluate the possible correlation between serum FGF2 levels and its diagnostic parameters in patients with heart failure.

METHODS

Plasma FGF2 concentration was measured in 114 patients with a complaint of dyspnea (enrolled in the study between January 2022 and August 2022). Based on heart failure diagnosis, the patients were assigned to three groups, as follows: heart failure (n = 80), non-heart-failure dyspnea (n = 34), and healthy controls (n = 36), following physical examination. Possible correlations between serum FGF2 levels and other prognostic parameters in patients with heart failure were analyzed.

RESULTS

Serum FGF2 levels were higher in patients with heart failure (125.60 [88.95, 183.40] pg/mL) than in those with non-heart-failure dyspnea (65.30 [28.85, 78.95] pg/mL) and healthy controls (78.90 [60.80, 87.20] pg/mL) (p < 0.001). Receiver operating characteristic curve analysis identified FGF2 concentration as a significant predictor in heart failure diagnosis, with an area under the curve of 0.8693 (p < 0.0001). Importantly, in the heart failure group, serum FGF2 concentrations correlated with key prognostic parameters for heart failure, such as reduced left ventricular ejection fraction and elevated serum levels of N-terminal pro-B-type natriuretic peptide.

CONCLUSIONS

Elevated serum FGF2 level is strongly associated with an increased risk of heart failure and could serve as a useful biomarker to complement vital diagnostic parameters for heart failure.

Antifibrotic effects of sodium-glucose cotransporter-2 inhibitors: A comprehensive review

BACKGROUND AND AIMS

Scar tissue accumulation in organs is the underlying cause of many fibrotic diseases. Due to the extensive array of organs affected, the long-term nature of fibrotic processes and the large number of people who suffer from the negative impact of these diseases, they constitute a serious health problem for modern medicine and a huge economic burden on society. Sodium-glucose cotransporter-2 inhibitors (SGLT2is) are a relatively new class of anti-diabetic pharmaceuticals that offer additional benefits over and above their glucose-lowering properties; these medications modulate a variety of diseases, including fibrosis. Herein, we have collated and analyzed all available research on SGLT2is and their effects on organ fibrosis, together with providing a proposed explanation as to the underlying mechanisms.

METHODS

PubMed, ScienceDirect, Google Scholar and Scopus were searched spanning the period from 2012 until April 2023 to find relevant articles describing the antifibrotic effects of SGLT2is.

RESULTS

The majority of reports have shown that SGLT2is are protective against lung, liver, heart and kidney fibrosis as well as arterial stiffness. According to the results of clinical trials and animal studies, many SGLT2 inhibitors are promising candidates for the treatment of fibrosis. Recent studies have demonstrated that SGLT2is affect an array of cellular processes, including hypoxia, inflammation, oxidative stress, the renin-angiotensin system and metabolic activities, all of which have been linked to fibrosis.

CONCLUSION

Extensive evidence indicates that SGLT2is are promising treatments for fibrosis, demonstrating protective effects in various organs and influencing key cellular processes linked to fibrosis.

Towards a point-of-care multimodal spectroscopy instrument for the evaluation of human cardiac tissue

To demonstrate that point-of-care multimodal spectroscopy using Near-Infrared (NIR) and Raman Spectroscopy (RS) can be used to diagnose human heart tissue. We generated 105 spectroscopic scans, which comprised 4 NIR and 3 RS scans per sample to generate a "multimodal spectroscopic scan" (MSS) for each heart, done across 15 patients, 5 each from the dilated cardiomyopathy (DCM), Ischaemic Heart Disease (IHD) and Normal pathologies. Each of the MSS scans was undertaken in 3 s. Data were entered into machine learning (ML) algorithms to assess accuracy of MSS in diagnosing tissue type. The median age was 50 years (IQR 49-52) for IHD, 47 (IQR 45-50) for DCM and 36 (IQR 33-52) for healthy patients (p = 0.35), 60% of which were male. MSS identified key differences in IHD, DCM and normal heart samples in regions typically associated with fibrosis and collagen (NIR wavenumbers: 1433, 1509, 1581, 1689 and 1725 nm; RS wavelengths: 1658, 1450 and 1330 cm-1). In principal component (PC) analyses, these differences explained 99.2% of the variation in 4 PCs for NIR, 81.6% in 10 PCs for Raman, and 99.0% in 26 PCs for multimodal spectroscopic signatures. Using a stack machine learning algorithm with combined NIR and Raman data, our model had a precision of 96.9%, recall of 96.6%, specificity of 98.2% and Area Under Curve (AUC) of 0.989 (Table 1). NIR and Raman modalities alone had similar levels of precision at 94.4% and 89.8% respectively (Table 1). MSS combined with ML showed accuracy of 90% for detecting dilated cardiomyopathy, 100% for ischaemic heart disease and 100% for diagnosing healthy tissue. Multimodal spectroscopic signatures, based on NIR and Raman spectroscopy, could provide cardiac tissue scans in 3-s to aid accurate diagnoses of fibrosis in IHD, DCM and normal hearts. Table 1 Machine learning performance metrics for validation data sets of (a) Near-Infrared (NIR), (b) Raman and (c and d) multimodal data using logistic regression (LR), stochastic gradient descent (SGD) and support vector machines (SVM), with combined "stack" (LR + SGD + SVM) AUC Precision Recall Specificity (a) NIR model  Logistic regression 0.980 0.944 0.933 0.967  SGD 0.550 0.281 0.400 0.700  SVM 0.840 0.806 0.800 0.900  Stack 0.933 0.794 0.800 0.900 (b) Raman model  Logistic regression 0.985 0.940 0.929 0.960  SGD 0.892 0.869 0.857 0.932  SVM 0.992 0.940 0.929 0.960  Stack 0.954 0.869 0.857 0.932 (c) MSS: multimodal (NIR + Raman) to detect DCM vs. IHD vs. normal patients  Logistic regression 0.975 0.841 0.828 0.917  SGD 0.847 0.803 0.793 0.899  SVM 0.971 0.853 0.828 0.917  Stack 0.961 0.853 0.828 0.917 (d) MSS: multimodal (NIR + Raman) to detect pathological vs. normal patients  Logistic regression 0.961 0.969 0.966 0.984  SGD 0.944 0.967 0.966 0.923  SVM 1.000 1.000 1.000 1.000  Stack 1.000 0.944 0.931 0.969 Bold values indicate values obtained from the stack algorithm and used for analyses.

Hypertrophic Cardiomyopathy-Advances in Imaging and Diagnostic Strategies

Hypertrophic cardiomyopathy (HCM) is the most important and prevalent cardiac disease in cats. Due to the highly variable nature of HCM, a multimodal approach including physical examination, genetic evaluation, cardiac biomarkers, and imaging are all essential elements to appropriate and timely diagnosis. These foundational elements are advancing rapidly in veterinary medicine. Newer biomarkers such as galectin-3 are currently being researched and advances in tissue speckle-tracking and contrast-enhanced echocardiography are readily available. Advanced imaging techniques, such as cardiac MRI, are providing previously unavailable information about myocardial fibrosis and paving the way for enhanced diagnostic capabilities and risk-stratification in cats with HCM.

Beyond Angiotensin-Converting Enzyme Inhibitors: Modulation of the Renin-Angiotensin-Aldosterone System to Delay or Manage Congestive Heart Failure

The renin-angiotensin-aldosterone system (RAAS) consists of bioactive angiotensin peptides, enzymatic pathways, receptors, and the steroid hormone aldosterone. The RAAS regulates blood pressure, sodium, and electrolyte homeostasis and mediates pathologic disease processes. Within this system is an alternative arm that counterbalances the vasoconstrictive, sodium and water retentive, and pro-fibrotic and inflammatory effects of the classical arm. Improved biochemical methodologies in RAAS quantification are elucidating how this complex system changes in health and disease. Future treatments for cardiovascular and kidney disease will likely involve a more nuanced manipulation of this system rather than simple blockade.

Point-of-care detection of fibrosis in liver transplant surgery using near-infrared spectroscopy and machine learning

Introduction

Visual assessment and imaging of the donor liver are inaccurate in predicting fibrosis and remain surrogates for histopathology. We demonstrate that 3-s scans using a handheld near-infrared-spectroscopy (NIRS) instrument can identify and quantify fibrosis in fresh human liver samples.

Methods

We undertook NIRS scans on 107 samples from 27 patients, 88 from 23 patients with liver disease, and 19 from four organ donors.

Results

Liver disease patients had a median immature fibrosis of 40% (interquartile range [IQR] 20-60) and mature fibrosis of 30% (10%-50%) on histopathology. The organ donor livers had a median fibrosis (both mature and immature) of 10% (IQR 5%-15%). Using machine learning, this study detected presence of cirrhosis and METAVIR grade of fibrosis with a classification accuracy of 96.3% and 97.2%, precision of 96.3% and 97.0%, recall of 96.3% and 97.2%, specificity of 95.4% and 98.0% and area under receiver operator curve of 0.977 and 0.999, respectively. Using partial-least square regression machine learning, this study predicted the percentage of both immature (R 2 = 0.842) and mature (R 2 = 0.837) with a low margin of error (root mean square of error of 9.76% and 7.96%, respectively).

Conclusion

This study demonstrates that a point-of-care NIRS instrument can accurately detect, quantify and classify liver fibrosis using machine learning.

Rationale and design of the ARAMIS trial: Anakinra versus placebo, a double blind randomized controlled trial for the treatment of acute myocarditis

BACKGROUND

Acute myocarditis is an inflammation of the myocardium that can cause life-threatening events. However, anti-inflammatory strategies did not reduce the risk of clinical outcomes in randomized trials. Recently, experimental studies have suggested that specific blockade of the interleukin-1β immune innate pathway could be effective in acute myocarditis.

AIM

To test the hypothesis that inhibition of the interleukin-1β immune innate pathway can reduce the risk of clinical events in acute myocarditis.

METHODS

The "Anakinra versus placebo double blind Randomized controlled trial for the treatment of Acute MyocarditIS" (ARAMIS) trial (ClinicalTrials.gov identifier: NCT03018834) is a national multicentre randomized parallel-group double blind study among symptomatic patients with elevated cardiac troponin and cardiac magnetic resonance-proven acute myocarditis. Patients (n=120) are randomized within 72hours of hospital admission to receive a daily subcutaneous dose of anakinra 100mg or placebo during the hospitalization, in addition to standard of care, including an angiotensin-converting enzyme inhibitor and a beta-blocker. The primary endpoint is the number of days alive free from any myocarditis complication, including ventricular arrhythmias, heart failure, recurrent chest pain requiring medication and ventricular dysfunction (defined as left ventricular ejection fraction<50%), from randomization to 28 days after hospital discharge. At 28 days after discharge, patients with normal left ventricular ejection fraction are then randomized to angiotensin-converting enzyme inhibitor continuation or discontinuation and all patients are followed for 1 year, with regular left ventricular function evaluation.

CONCLUSIONS

ARAMIS is the first trial evaluating inhibition of the interleukin-1β immune innate pathway in the setting of acute myocarditis. Although of small size, it will be the largest randomized trial in acute myocarditis, a serious and poorly studied cardiac condition.

Progress and prospect of nanotechnology for cardiac fibrosis treatment

Cardiac fibrosis is the excessive accumulation of extracellular matrix components in the heart, leading to reduced cardiac functionality and heart failure. This review provides an overview of the therapeutic applications of nanotechnology for the treatment of cardiac fibrosis. We first delve into the fundamental pathophysiology of cardiac fibrosis, highlighting the key molecular players, including Matrix Metalloproteinases, Transforming Growth Factor-beta, and several growth factors, cytokines, and signaling molecules. Each target presents a unique opportunity to develop targeted nano-therapies. We then focus on recent advancements in nanotechnology and how nanoparticles can be engineered to deliver drugs or therapeutic genes. These advanced delivery approaches have shown significant potential to inhibit fibrosis-promoting factors, thereby mitigating the fibrotic response and potentially reversing disease progression. In addition, we discuss the challenges associated with developing and translating nanotechnology-based drug delivery systems, including ensuring biocompatibility, safety, and regulatory compliance. This review highlights how nanotechnology can bridge the gap between lab research and clinical practice for treating cardiac fibrosis.

Insulin-Like Growth Factor 1 Receptor Deficiency Alleviates Angiotensin II-Induced Cardiac Fibrosis Through the Protein Kinase B/Extracellular Signal-Regulated Kinase/Nuclear Factor-κB Pathway

Background The renin-angiotensin system plays a crucial role in the development of heart failure, and Ang II (angiotensin II) acts as the critical effector of the renin-angiotensin system in regulating cardiac fibrosis. However, the mechanisms of cardiac fibrosis are complex and still not fully understood. IGF1R (insulin-like growth factor 1 receptor) has multiple functions in maintaining cardiovascular homeostasis, and low-dose IGF1 treatment is effective in relieving Ang II-induced cardiac fibrosis. Here, we aimed to investigate the molecular mechanism of IGF1R in Ang II-induced cardiac fibrosis. Methods and Results Using primary mouse cardiac microvascular endothelial cells and fibroblasts, in vitro experiments were performed. Using C57BL/6J mice and clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated 9 (Cas9)-mediated IGF1R heterozygous knockout (Igf1r+/-) mice, cardiac fibrosis mouse models were induced by Ang II for 2 weeks. The expression of IGF1R was examined by quantitative reverse transcription polymerase chain reaction, immunohistochemistry, and Western blot. Mice heart histologic changes were evaluated using Masson and picro sirius red staining. Fibrotic markers and signal molecules indicating the function of the Akt (protein kinase B)/ERK (extracellular signal-regulated kinase)/nuclear factor-κB pathway were detected using quantitative reverse transcription polymerase chain reaction and Western blot. RNA sequencing was used to explore IGF1R-mediated target genes in the hearts of mice, and the association of IGF1R and G-protein-coupled receptor kinase 5 was identified by coimmunoprecipitation. More important, blocking IGF1R signaling significantly suppressed endothelial-mesenchymal transition in primary mouse cardiac microvascular endothelial cells and mice in response to transforming growth factor-β1 or Ang II, respectively. Deficiency or inhibition of IGF1R signaling remarkably attenuated Ang II-induced cardiac fibrosis in primary mouse cardiac fibroblasts and mice. We further observed that the patients with heart failure exhibited higher blood levels of IGF1 and IGF1R than healthy individuals. Moreover, Ang II treatment significantly increased cardiac IGF1R in wild type mice but led to a slight downregulation in Igf1r+/- mice. Interestingly, IGF1R deficiency significantly alleviated cardiac fibrosis in Ang II-treated mice. Mechanistically, the phosphorylation level of Akt and ERK was upregulated in Ang II-treated mice, whereas blocking IGF1R signaling in mice inhibited these changes of Akt and ERK phosphorylation. Concurrently, phosphorylated p65 of nuclear factor-κB exhibited similar alterations in the corresponding group of mice. Intriguingly, IGF1R directly interacted with G-protein-coupled receptor kinase 5, and this association decreased ≈50% in Igf1r+/- mice. In addition, Grk5 deletion downregulated expression of the Akt/ERK/nuclear factor-κB signaling pathway in primary mouse cardiac fibroblasts. Conclusions IGF1R signaling deficiency alleviates Ang II-induced cardiac fibrosis, at least partially through inhibiting endothelial-mesenchymal transition via the Akt/ERK/nuclear factor-κB pathway. Interestingly, G-protein-coupled receptor kinase 5 associates with IGF1R signaling directly, and it concurrently acts as an IGF1R downstream effector. This study suggests the promising potential of IGF1R as a therapeutic target for cardiac fibrosis.

Quantification of myocardial extracellular volume without blood sampling

Aims

Cardiac magnetic resonance (CMR) T1 relaxation time mapping is an established technique primarily used to identify diffuse interstitial fibrosis and oedema. The myocardial extracellular volume (ECV) can be calculated from pre- and post-contrast T1 relaxation times and is a reproducible parametric index of the proportion of volume occupied by non-cardiomyocyte components in myocardial tissue. The conventional calculation of the ECV requires blood sampling to measure the haematocrit (HCT). Given the high variability of the HCT, the blood collection is recommended within 24 h of the CMR scan, limiting its applicability and posing a barrier to the clinical routine use of ECV measurements. In recent years, several research groups have proposed a method to determine the ECV by CMR without blood sampling. This is based on the inverse relationship between the T1 relaxation rate (R1) of blood and the HCT. Consequently, a 'synthetic' HCT could be estimated from the native blood R1, avoiding blood sampling.

Methods and results

We performed a review and meta-analysis of published studies on synthetic ECV, as well as a secondary analysis of previously published data to examine the effect of the chosen regression modell on bias. While, overall, a good correlation and little bias between synthetic and conventional ECV were found in these studies, questions regarding its accuracy remain.

Conclusion

Synthetic HCT and ECV can provide a 'non-invasive' quantitative measurement of the myocardium's extracellular space when timely HCT measurements are not available and large alterations in ECV are expected, such as in cardiac amyloidosis. Due to the dependency of T1 relaxation times on the local setup, calculation of local formulas using linear regression is recommended, which can be easily performed using available data.

Flt3 Activation Mitigates Mitochondrial Fragmentation and Heart Dysfunction through Rebalanced L-OPA1 Processing by Hindering the Interaction between Acetylated p53 and PHB2 in Cardiac Remodeling

Recent studies have shown that FMS-like receptor tyrosine kinase 3 (Flt3) has a beneficial effect on cardiac maladaptive remodeling. However, the role and mechanism of Flt3 in mitochondrial dynamic imbalance under cardiac stress remains poorly understood. This study aims to investigate how Flt3 regulates p53-mediated optic atrophy 1 (OPA1) processing and mitochondrial fragmentation to improve cardiac remodeling. Mitochondrial fragmentation in cardiomyocytes was induced by isoprenaline (ISO) and H2O2 challenge, respectively, in vitro. Cardiac remodeling in mice was established by ligating the left anterior descending coronary artery or by chronic ISO challenge, respectively, in vivo. Our results demonstrated that the protein expression of acetylated-p53 (ac-p53) in mitochondria was significantly increased under cell stress conditions, facilitating the dissociation of PHB2-OPA1 complex by binding to prohibitin 2 (PHB2), a molecular chaperone that stabilizes OPA1 in mitochondria. This led to the degradation of the long isoform of OPA1 (L-OPA1) that facilitates mitochondrial fusion and resultant mitochondrial network fragmentation. This effect was abolished by a p53 K371R mutant that failed to bind to PHB2 and impeded the formation of the ac-p53-PHB2 complex. The activation of Flt3 significantly reduced ac-p53 expression in mitochondria via SIRT1, thereby hindering the formation of the ac-p53-PHB2 complex and potentiating the stability of the PHB2-OPA1 complex. This ultimately inhibits L-OPA1 processing and leads to the balancing of mitochondrial dynamics. These findings highlight a novel mechanism by which Flt3 activation mitigates mitochondrial fragmentation and dysfunction through the reduction of L-OPA1 processing by dampening the interaction between ac-p53 and PHB2 in cardiac maladaptive remodeling.

Characterizing the Heart and the Myocardium With Photon-Counting CT

ABSTRACT

Noninvasive cardiac imaging has rapidly evolved during the last decade owing to improvements in computed tomography (CT)-based technologies, among which we highlight the recent introduction of the first clinical photon-counting detector CT (PCD-CT) system. Multiple advantages of PCD-CT have been demonstrated, including increased spatial resolution, decreased electronic noise, and reduced radiation exposure, which may further improve diagnostics and may potentially impact existing management pathways. The benefits that can be obtained from the initial experiences with PCD-CT are promising. The implementation of this technology in cardiovascular imaging allows for the quantification of coronary calcium, myocardial extracellular volume, myocardial radiomics features, epicardial and pericoronary adipose tissue, and the qualitative assessment of coronary plaques and stents. This review aims to discuss these major applications of PCD-CT with a focus on cardiac and myocardial characterization.

Galectin-3 as a novel biomarker in cats with hypertrophic cardiomyopathy

INTRODUCTION/OBJECTIVES

Galectin-3 (Gal-3) is a circulating biomarker of fibrosis. In humans, increased Gal-3 is predictive of myocardial fibrosis and adverse cardiac events. The aim of this study was to evaluate the potential for Gal-3 as a cardiac biomarker in cats with hypertrophic cardiomyopathy (HCM).

MATERIALS AND METHODS

Eighty cats were enrolled (25 healthy cats with normal hearts, 35 with HCM American College of Veterinary Internal Medicine (ACVIM) stage B, and 21 with HCM ACVIM stage C). Each cat received a full echocardiogram, health panel, and total thyroxin level. Galectin-3 levels were measured for each enrolled patient. Troponin I and N-terminal pro-brain natriuretic peptide (NT-proBNP) were obtained for the majority of cats. Additionally, 17 ACVIM stage B cats underwent cardiac-gated magnetic resonance (CMR) imaging to assess myocardial extracellular volume (ECV), a noninvasive measure of myocardial fibrosis.

RESULTS

Galectin-3 levels are increased in cats with HCM ACVIM stage B and C compared to healthy cats; however, no significant differences were detected between ACVIM stage B and ACVIM stage C cats. In HCM-affected cats, Galectin-3 showed statistically significant correlations with left atrial dimensions, left atrial:aorta ratio, and CMR-derived ECV. Quantitative NT-proBNP showed excellent discrimination between all groups and troponin I was able to discriminate between ACVIM stage C and normal cats, but not between other groups.

CONCLUSIONS

Circulating Gal-3 levels are increased in cats with HCM and is positively correlated with left atrial dimensions and ECV in affected cats. Further studies evaluating the relationship between Gal-3, myocardial fibrosis, and clinical outcomes are warranted.

Renin-Angiotensin System: Updated Understanding and Role in Physiological and Pathophysiological States

The classical view of the renin-angiotensin system (RAS) is that of the circulating hormone pathway involved in salt and water homeostasis and blood pressure regulation. It is also involved in the pathogenesis of cardiac and renal disorders. This led to the creation of drugs blocking the actions of this classical pathway, which improved cardiac and renal outcomes. Our understanding of the RAS has significantly expanded with the discovery of new peptides involved in this complex pathway. Over the last two decades, a counter-regulatory or protective pathway has been discovered that opposes the effects of the classical pathway. Components of RAS are also implicated in the pathogenesis of obesity and its metabolic diseases. The continued discovery of newer molecules also provides novel therapeutic targets to improve disease outcomes. This article aims to provide an overview of an updated understanding of the RAS, its role in physiological and pathological processes, and potential novel therapeutic options from RAS for managing cardiorenal disorders, obesity, and related metabolic disorders.

A comprehensive review of acute cardio-renal syndrome: need for novel biomarkers

Cardiorenal syndrome represents a wide-spectrum disorder involving the heart and kidneys as the primary affected organs. India has an increasingly high burden of acute CRS, coinciding with the rise in global statistics. Up to 2022, approximately 46.1% of all cardiorenal patients have been diagnosed with acute CRS in India. Acute CRS involves a sudden deterioration of kidney functionalities, referred to as acute kidney injury (AKI) in acute heart failure patients. The pathophysiology of CRS involves hyperactivation of the sympathetic nervous system (SNS) and the renin-angiotensin-aldosterone system (RAAS) following acute myocardial stress. The pathological phenotype of acute CRS is associated with perturbed inflammatory, cellular, and neurohormonal markers in circulation. These complications increase the risk of mortality in clinically diagnosed acute CRS patients, making it a worldwide healthcare burden. Hence, effective diagnosis and early prevention are crucial to prevent the progression of CRS in AHF patients. Present biomarkers, such as serum creatinine (sCr), cystatin C (CysC), glomerular filtration rate (GFR), blood urea nitrogen (BUN), serum and/or urine neutrophil gelatinase-associated lipocalin (NGAL), B-type natriuretic peptide (BNP), and NT-proBNP, are clinically used to diagnose AKI stages in CRS patients but are limitedly sensitive to the early detection of the pathology. Therefore, the need for protein biomarkers is emerging for early intervention in CRS progression. Here, we summarized the cardio-renal nexus in acute CRS, with an emphasis on the present clinicopathological biomarkers and their limitations. The objective of this review is to highlight the need for novel proteomic biomarkers that will curb the burgeoning concern and direct future research trials.

Left ventricular adaptation to aortic regurgitation in adults with repaired coarctation of aorta

BACKGROUND

Aortic regurgitation (AR) can develop in adults with repaired coarctation of aorta (COA), but there are limited data about left ventricular (LV) remodeling and clinical outcomes in this population. The purpose of the study was to compare LV remodeling (LV mass index [LVMI], LV ejection fraction [LVEF], and septal E/e') and onset of symptoms before aortic valve replacement, and LV reverse remodeling (%-change in LVMI, LVEF and E/e') after aortic valve replacement in patients with versus without repaired COA presenting with AR.

METHODS

Asymptomatic adults with repaired COA presenting with moderate/severe AR (AR-COA group) were matched 1:2 to asymptomatic adults without COA and similar severity of AR (control group).

RESULTS

Although both groups (AR-COA n = 52, and control n = 104) had similar age, sex, body mass index, aortic valve gradient, and AR severity, the AR-COA group had higher LVMI (124 ± 28 versus 102 ± 25 g/m², p < 0.001) and E/e' (12.3 ± 2.3 versus 9.5 ± 2.1, p = 0.02) but similar LVEF (63 ± 9% versus 67 ± 10%, p = 0.4). COA diagnosis (adjusted HR 1.95, 95%CI 1.49-2.37, p < 0.001), older age, E/e', and LV hypertrophy were associated with onset of symptoms. Of 89 patients (AR-COA n = 41, and control n = 48) with echocardiographic data at 1-year post- aortic valve replacement, the AR-COA group had less regression of LVMI (-8% [95%CI -5 to -11] versus -17% [95%CI -15 to -21], p < 0.001) and E/e' (-5% [95% CI -3 to -7] versus -16% [95% CI -13 to -19], p < 0.001).

CONCLUSIONS

Patients with COA and AR had a more aggressive clinical course, and perhaps may require a different threshold for surgical intervention.

Case report: Diagnosis of apical hypertrophic cardiomyopathy that escaped clinical and echocardiographic investigations for twenty years: Reasons and clinical implications

BACKGROUND

Apical hypertrophic cardiomyopathy (ApHCM) is a rare form of hypertrophic cardiomyopathy which predominantly affects the apex of the left ventricle. The diagnosis can be challenging due to several factors, ranging from no typical clinical and electrocardiogram (EKG) findings to potential difficulties in executing and interpreting the echocardiographic examination.

CASE PRESENTATION

We report the case of an 84-year-old woman who came to our echo-lab to undergo a routine echocardiogram. She had a history of permanent atrial fibrillation, paced rhythm and previous episodes of heart failure (HF), allegedly explained by a diagnosis of hypertensive heart disease that had been confirmed many times over the previous 20 years. The clinical examination and the EKG were unremarkable. The echocardiographic images were poor quality. But a senior cardiologist, expert in imaging and echocardiography, noted the lack of delineation of the endocardial border of the left ventricular (LV) apex region. Contrast echocardiography was performed and severe apical hypertrophy discovered.

CONCLUSION

ApHCM can be a challenging diagnosis. Contrast echocardiography must always be applied in cases of poor delineation of the LV apical endocardial border at baseline echocardiography. Timely detection and appropriate lifestyle intervention might slow the development of LV hypertrophy, and possibly minimize and delay heart failure (HF) related symptoms and arrhythmias. The prognosis remains relatively benign during long term follow-up.

A novel caffeic acid derivative prevents angiotensin II-induced cardiac remodeling

Differentiation of cardiac fibroblasts into myofibroblasts is a critical event in the progression of cardiac fibrosis that causes pathological cardiac remodeling. Cardiac fibrosis is a hallmark of heart disease and is associated with a stiff myocardium and heart failure. This study investigated the effect of caffeic acid ethanolamide (CAEA), a novel caffeic acid derivative, on cardiac remodeling. Angiotensin (Ang) II was used to induce cardiac remodeling both in cell and animal studies. Treating cardiac fibroblast with CAEA in Ang II-exposed cell cultures reduced the expression of fibrotic marker α-smooth muscle actin (α-SMA) and collagen and the production of superoxide, indicating that CAEA inhibited the differentiation of fibroblast into myofibroblast after Ang II exposure. CAEA protects against Ang II-induced cardiac fibrosis and dysfunction in vivo, characterized by the alleviation of collagen accumulation and the recovery of ejection fraction. In addition, CAEA decreased Ang II-induced transforming growth factor-β (TGF-β) expression and reduced NOX4 expression and oxidative stress in a SMAD-dependent pathway. CAEA participated in the regulation of Ang II-induced TGF-β/SMAD/NOX4 signaling to prevent the differentiation of fibroblast into myofibroblast and thus exerted a cardioprotective effect. Our data support the administration of CAEA as a viable method for preventing the progression of Ang II-induced cardiac remodeling.

Dynamic mechanobiology of cardiac cells and tissues: Current status and future perspective

Mechanical forces impact cardiac cells and tissues over their entire lifespan, from development to growth and eventually to pathophysiology. However, the mechanobiological pathways that drive cell and tissue responses to mechanical forces are only now beginning to be understood, due in part to the challenges in replicating the evolving dynamic microenvironments of cardiac cells and tissues in a laboratory setting. Although many in vitro cardiac models have been established to provide specific stiffness, topography, or viscoelasticity to cardiac cells and tissues via biomaterial scaffolds or external stimuli, technologies for presenting time-evolving mechanical microenvironments have only recently been developed. In this review, we summarize the range of in vitro platforms that have been used for cardiac mechanobiological studies. We provide a comprehensive review on phenotypic and molecular changes of cardiomyocytes in response to these environments, with a focus on how dynamic mechanical cues are transduced and deciphered. We conclude with our vision of how these findings will help to define the baseline of heart pathology and of how these in vitro systems will potentially serve to improve the development of therapies for heart diseases.

Biochemical evidence of PM2.5 critical components for inducing myocardial fibrosis in vivo and in vitro

PM_2.5 constituents are tightly linked to the initiation of many cardiovascular diseases (CVDs). Little is known, however, about the events which critical components of PM_2.5 can induce the initiating events in CVDs. C57BL/6 female mice were exposed to PM_2.5 (3 mg/kg b.w.) from four different cities (Taiyuan, Beijing, Hangzhou, and Guangzhou) by oropharyngeal aspiration every other day. PM_2.5 from Taiyuan increased the diastolic function of the hearts and induced myocardial fibrosis with increased areas of interstitial fibrosis through the NOX4/TGF-β1/Smad 3/Col1a1 pathways. Pb, Cr, Mn, Zn, and most of the polycyclic aromatic hydrocarbons (PAHs) were positively associated with the related indicators of cardiac diastolic function and myocardial fibrosis by using Pearson correlation (R² = 0.9085-0.9897). To determine the critical components in PM_2.5 that can induce the occurrence of myocardial fibrosis, BEAS-2b cells were treated with one or more of five candidate components with/without Guangzhou PM_2.5, and then the conditioned medium of BEAS-2b was used to culture AC16 cells. The results showed that Zn + Pb + Mn + BaP with PM_2.5 from Guangzhou exposure significantly increased reactive oxygen species production of BEAS-2b cells and induced a dramatic increase of myocardial fiber-related gene expression (Col1a1 and TGF-β) in AC16 cells. It indicated that the different mass concentrations of Zn, Pb, Mn, and ΣPAHs in PM_2.5 might be the critical factors that modulated myocardial fibrosis induction by targeted. Our study provided a novel avenue for further elucidation of molecular mechanisms of PM_2.5 components-induced myocardial fibrosis.

Research Update on the Pathophysiological Mechanisms of Heart Failure with Preserved Ejection Fraction

Heart failure (HF) is a serious clinical syndrome, usually occurs at the advanced stage of various cardiovascular diseases, featured by high mortality and rehospitalization rate. According to left ventricular (LV) ejection fraction (LVEF), HF has been categorized as HF with reduced EF (HFrEF; LVEF<40%), HF with mid-range EF (HFmrEF; LVEF 40-49%), and HF with preserved EF (HFpEF; LVEF ≥50%). HFpEF accounts for about 50% of cases of heart failure and has become the dominant form of heart failure. The mortality of HFpEF is similar to that of HFrEF. There are no welldocumented treatment options that can reduce the morbidity and mortality of HFpEF now. Understanding the underlying pathological mechanisms is essential for the development of novel effective therapy options for HFpEF. In recent years, significant research progress has been achieved on the pathophysiological mechanism of HFpEF. This review aimed to update the research progress on the pathophysiological mechanism of HFpEF.

Serum aldosterone effect on left ventricular structure and diastolic function in essential hypertension

Aldosterone has hypertrophic and profibrotic effects on the heart. This study aims to determine the relationship between serum aldosterone concentration (SAC) and aldosterone-to-renin ratio (ARR) with left ventricular (LV) geometry and diastolic function in essential hypertension (EH). We investigated 213 EH patients (50.3 ± 12.6 years; 57.7% male). SAC, ARR measurements, and echocardiographic analysis were performed for participants. Overall, stepwise multiple regression analysis showed significant associations between SAC and interventricular septum, LV posterior wall thickness, LV amass, LV mass index, e' velocity, a' velocity, and E/e' ratio after adjustment of potentially confounding covariates. When patients were divided into three SAC tertiles, multivariate-adjusted analysis of covariance (ANCOVA) demonstrated a significant increase in LV mass (P ˂ 0.001), LV mass index (P ˂ 0.001), relative wall thickness (P = 0.003), interventricular septum (P = 0.001), LV posterior wall thickness (P = 0.001) and E/e' ratio (P ˂ 0.001), but a decrease in e' velocity (P = 0.002) from the first to third tertile of SAC. In logistic regression analysis, increased SAC was independently associated with concentric LV hypertrophy [OR: 1.21, 95% CI: 1.11-1.33, P ˂ 0.001]. No significant associations were found between ARR and echocardiographic parameters of LV structure or diastolic function. In conclusion, SAC, but not ARR, is independently associated with echocardiographic indices of LV structure and diastolic function and is also related to concentric LV hypertrophy. Our findings suggest that aldosterone's pro-hypertrophic and myocardial fibrosis effects contribute to alterations in LV structure and diastolic function in EH beyond blood pressure.

Apitherapy combination improvement of blood pressure, cardiovascular protection, and antioxidant and anti-inflammatory responses in dexamethasone model hypertensive rats

Hypertension-induced ventricular and vascular remodeling causes myocardial infarction, heart failure, and sudden death. Most available pharmaceutical products used to treat hypertension lead to adverse effects on human health. Limited data is available on apitherapy (bee products) combinations for treatment of hypertension. This study aims to evaluate the antihypertensive effects of combinations of natural apitherapy compounds used in the medical sector to treat a variety of diseases. Rats were assigned into six groups consisting of one control group and five hypertensive groups where hypertension (blood pressure > 140/90) was induced with dexamethasone. One of these groups was used as a hypertension model, while the remaining four hypertensive groups were treated with a propolis, royal jelly, and bee venom combination (PRV) at daily oral doses of 0.5, 1.0, and 2.0 mg/kg, and with losartan 10 mg/kg. The PRV combination at all doses decreased arterial blood pressure below the suboptimal value (p < 0.001), and PRV combination treatment improved dexamethasone-induced-ECG changes. The same treatment decreased angiotensin-II, endothelin-1, and tumor growth factor β serum levels in hypertensive rats. Additionally, PRV combination improved histopathological structure, and decreased serum levels of NF-kB and oxidative stress biomarkers. We concluded that PRV combination therapy may be used as a potential treatment for a variety of cardiovascular diseases.

Exploring the cardiac ECM during fibrosis: A new era with next-gen proteomics

Extracellular matrix (ECM) plays a critical role in maintaining elasticity in cardiac tissues. Elasticity is required in the heart for properly pumping blood to the whole body. Dysregulated ECM remodeling causes fibrosis in the cardiac tissues. Cardiac fibrosis leads to stiffness in the heart tissues, resulting in heart failure. During cardiac fibrosis, ECM proteins get excessively deposited in the cardiac tissues. In the ECM, cardiac fibroblast proliferates into myofibroblast upon various kinds of stimulations. Fibroblast activation (myofibroblast) contributes majorly toward cardiac fibrosis. Other than cardiac fibroblasts, cardiomyocytes, epithelial/endothelial cells, and immune system cells can also contribute to cardiac fibrosis. Alteration in the expression of the ECM core and ECM-modifier proteins causes different types of cardiac fibrosis. These different components of ECM culminated into different pathways inducing transdifferentiation of cardiac fibroblast into myofibroblast. In this review, we summarize the role of different ECM components during cardiac fibrosis progression leading to heart failure. Furthermore, we highlight the importance of applying mass-spectrometry-based proteomics to understand the key changes occurring in the ECM during fibrotic progression. Next-gen proteomics studies will broaden the potential to identify key targets to combat cardiac fibrosis in order to achieve precise medicine-development in the future.

Role of Cardiac Natriuretic Peptides in Heart Structure and Function

Cardiac natriuretic peptides (NPs), atrial NP (ANP) and B-type NP (BNP) are true hormones produced and released by cardiomyocytes, exerting several systemic effects. Together with C-type NP (CNP), mainly expressed by endothelial cells, they also exert several paracrine and autocrine activities on the heart itself, contributing to cardiovascular (CV) health. In addition to their natriuretic, vasorelaxant, metabolic and antiproliferative systemic properties, NPs prevent cardiac hypertrophy, fibrosis, arrhythmias and cardiomyopathies, counteracting the development and progression of heart failure (HF). Moreover, recent studies revealed that a protein structurally similar to NPs mainly produced by skeletal muscles and osteoblasts called musclin/osteocrin is able to interact with the NPs clearance receptor, attenuating cardiac dysfunction and myocardial fibrosis and promoting heart protection during pathological overload. This narrative review is focused on the direct activities of this molecule family on the heart, reporting both experimental and human studies that are clinically relevant for physicians.