Exploring the anti­oxidative mechanisms of Rhodiola rosea in ameliorating myocardial fibrosis through network pharmacology and in vitro experiments.

Myocardial fibrosis (MF) significantly compromises cardiovascular health by affecting cardiac function through excessive collagen deposition. This impairs myocardial contraction and relaxation and leads to severe complications and increased mortality. The present study employed network pharmacology and in vitro assays to investigate the bioactive compounds of Rhodiola rosea and their targets. Using databases such as HERB, the Encyclopedia of Traditional Chinese Medicine, Pubchem, OMIM and GeneCards, the present study identified effective components and MF­related targets. Network analysis was conducted with Cytoscape to develop a Drug­Ingredient­Target­Disease network and the STRING database was utilized to construct a protein­protein interaction network. Key nodes were analyzed for pathway enrichment using Gene Ontology and Kyoto Encyclopedia of Genes and Genomes. Molecular interactions were further explored through molecular docking techniques. The bioactivity of salidroside (SAL), the principal component of Rhodiola rosea, against MF was experimentally validated in H9c2 cardiomyocytes treated with angiotensin II and assessed for cell viability, protein expression and oxidative stress markers. Network pharmacology identified 25 active ingredients and 372 targets in Rhodiola rosea, linking SAL with pathways such as MAPK, EGFR, advanced glycosylation end products­advanced glycosylation end products receptor and Forkhead box O. SAL showed significant interactions with core targets such as albumin, IL6, AKT serine/threonine kinase 1, MMP9 and caspase­3. In vitro, SAL mitigated AngII­induced increases in collagen I and alpha smooth muscle actin protein levels and oxidative stress markers, demonstrating dose­dependent effectiveness in reversing MF. SAL from Rhodiola rosea exhibited potent anti­oxidative properties that mitigated MF by modulating multiple molecular targets and signaling pathways. The present study underscored the therapeutic potential of SAL in treating oxidative stress­related cardiovascular diseases.

Reproducibility of myocardial extracellular volume quantification using dual-energy computed tomography in patients with cardiac amyloidosis.

BACKGROUND: Quantifying myocardial extracellular volume (ECV) using computed tomography (CT) has been shown to be useful in the evaluation of cardiac amyloidosis. However, the reproducibility of CT measurements for myocardial ECV, is not well-established in patients with proven cardiac amyloidosis. METHODS: This prospective single-center study enrolled cardiac amyloidosis patients to undergo dual-energy CT for myocardial fibrosis assessment. Delayed imaging at 7 and 8 â€‹min post-contrast and independent evaluations by two blinded cardiologists were performed for ECV quantification using 16-segment (ECVglobal) and septal sampling (ECVseptal). Inter- and intraobserver variability and test-retest reliability were measured using Spearman's rank correlation, Bland-Altman analysis, and intraclass correlation coefficients (ICC). RESULTS: Among the 24 participants (median age â€‹= â€‹78, 67 â€‹% male), CT ECVglobal and ECVseptal showed median values of 53.6 â€‹% and 49.1 â€‹% at 7 â€‹min, and 53.3 â€‹% and 50.1 â€‹% at 8 â€‹min, respectively. Inter- and intraobserver variability and test-retest reliability for CT ECVglobal (ICC â€‹= â€‹0.798, 0.912, and 0.894, respectively) and ECVseptal (ICC â€‹= â€‹0.791, 0.898, and 0.852, respectively) indicated good reproducibility, with no evidence of systemic bias between observers or scans. CONCLUSIONS: Dual-energy CT-derived ECV measurements demonstrated good reproducibility in patients with proven cardiac amyloidosis, suggesting potential utility as a repeatable imaging biomarker for this disease.

Microrna363-5p targets thrombospondin3 to regulate pathological cardiac remodeling.

Cardiac remodeling is an end-stage manifestation of multiple cardiovascular diseases, and microRNAs are involved in a variety of posttranscriptional regulatory processes. miR-363-5p targeting Thrombospondin3 (THBS3) has been shown to play an important regulatory role in vascular endothelial cells, but the roles of these two in cardiac remodeling are unknown. Firstly, we established an in vivo model of cardiac remodeling by transverse aortic narrow (TAC), and then we stimulated a human cardiomyocyte cell line (AC16) and a human cardiac fibroblast cell line (HCF) using 1 µmol/L angiotensin II (Ang II) to establish an in vitro model of cardiac hypertrophy and an in vitro model of myocardial fibrosis, respectively. In all three of the above models, we found a significant decreasing trend of miR-363-5p, suggesting that it plays a key regulatory role in the occurrence and development of cardiac remodeling. Subsequently, overexpression of miR-363-5p significantly attenuated myocardial hypertrophy and myocardial fibrosis in vitro as evidenced by reduced the area of AC16, the cell viability of HCFs, the relative expression of the protein of fetal genes (ANP, BNP, ß-MHC) and fibrosis marker (collagen I, collagen III, α-SMA), whereas inhibition of miR-363-5p expression showed the opposite trend. In addition, we also confirmed the targeted binding relationship between miR-363-5p and THBS3 by dual luciferase reporter gene assay, and the expression of THBS3 was directly inhibited by miR-363-5p. Moreover, overexpression of miR-363-5p with THBS3 simultaneously partially eliminated the delaying effect of miR-363-5p on myocardial hypertrophy and myocardial fibrosis in vitro. In conclusion, Overexpression of miR-363-5p attenuated the prohypertrophic and profibrotic effects of Ang II on AC16 and HCF by a mechanism related to the inhibition of THBS3 expression.

Speckle-tracking echocardiography as screening tool for myocardial fibrosis and Iron overload in transfusion-dependent beta-thalassemia.

BACKGROUND: Transfusion-dependent beta thalassemia (TDT) is a genetic disorder characterized by low haemoglobin levels, often leading to myocardial iron overload (MIO) and myocardial fibrosis (MF). Cardiac Magnetic Resonance (CMR) represents the gold standard for MIO and MF assessment, although its limited availability and high costs pose challenges. Left Ventricular Global Longitudinal Strain (LV GLS) measured by Speckle Tracking Echocardiography (STE) could offer a valuable alternative. METHODS: A monocentric diagnostic accuracy study was conducted to compare the performance of LV GLS with CMR using T2* for evaluating MIO and late gadolinium enhancement (LGE) for detecting MF. Between January 2022 and January 2023, 44 consecutive patients with TDT were enrolled. For each participant was performed LV GLS with STE, including CMR with T2* technique and LGE sequences. RESULTS: CMR identified MIO in 8 patients (18 %) and MF in 5 (11 %). LV GLS STE was normal in patients without MIO (-20.6 ± 3.1 %) or MF (-20.6 ± 2.8 %), significantly differing from those with MIO (-18.2 ± 2.1 %, p = 0.043) and MF (-16.4 ± 1.7 %, p = 0.002). ROC analysis indicated an optimal LV GLS STE cutoff of -19.8 % for MIO (AUC = 0.76, 95 % CI: 0.59-0.93, p = 0.054) with an overall diagnostic accuracy of 64 % and an optimal cutoff of -18.3 % for MF (AUC = 0.93, 95 % CI: 0.85-1.00, p = 0.009) with an accuracy of 86 %. CONCLUSIONS: The findings of this pilot study indicate that LV GLS with STE, may be a cost-effective screening tool for the early detection of MIO and MF in TDT patients.

Non-specific myocardial fibrosis in young competitive athletes: clinical significance and risk prediction by a powerful machine learning-based model.

BACKGROUND: Non-specific myocardial fibrosis (NSMF) is a heterogeneous entity. We aimed to evaluate young athletes with and without NSMF to establish potentially clinically significance. METHODS: We analysed data from 328 young athletes. We identified 61 with NSMF and compared them with 75 matched controls. Athletes with NSMF were divided into Group 1 (n = 28) with 'minor' fibrosis and Group 2 (n = 33) with non-insertion point fibrosis, defined as 'major'. Athletes were followed-up for adverse events. Finally, we tested various machine learning (ML) algorithms to create a prediction model for 'major' fibrosis. We created 4 different classifiers. RESULTS: Athletes of black ethnicity were more likely to have a subepicardial pattern (OR: 5.0, p = 0.004). Athletes with 'major' fibrosis demonstrated a higher prevalence of lateral T-wave inversion (TWI) ( < 0.001) and ventricular arrhythmias (VEs > 500/24 h, p = 0.046; non-sustained VT, p = 0.043). Athletes with 'minor' fibrosis demonstrated higher right ventricular volumes (p = 0.013), maximum Watts (p = 0.022) and maximum VO2 (p = 0.005). Lateral TWI (p = 0.026) and VO2 < 44 mL/min/Kg (p = 0.040) remained the only significant predictors for 'major' fibrosis. During follow up, athletes with 'major' fibrosis were 9.1 times more likely to exhibit adverse events (OR 13.4, p = 0.041). All ML models outperformed the benchmark method in predicting significant MF, best accuracy achieved by the random forest classifier (90%). CONCLUSIONS: Lateral TWI and reduced exercise performance are associated with higher burden of fibrosis. Fibrosis was associated with increased ventricular arrhythmia and adverse events. A comprehensive assessment can help develop a ML-based model for significant fibrosis, which could also guide clinical practice and appropriate CMR referrals.

Identification and Verification of Potential Markers Related to Myocardial Fibrosis by Bioinformatics Analysis.

Mounting evidence indicates that myocardial fibrosis (MF) is frequently intertwined with immune and metabolic disorders. This comprehensive review aims to delve deeply into the crucial role of immune-related signature genes in the pathogenesis and progression of MF. This exploration holds significant importance as understanding the underlying mechanisms of MF is essential for developing effective diagnostic and therapeutic strategies. The dataset GSE9735 about myocardial fibrosis and non-fibrosis was downloaded from GEO database. Differentially expressed genes (DEGs) were identified by 'limma' package in R software. Then, the biological function of DEG was determined by gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis. XCell was used to estimate the composition pattern of matrix and immune cells. Protein-protein interaction (PPI) network was constructed based on STRING analysis software, and Hub genes were screened and functional modules were analyzed. The correlation between hub genes and immune cell subtypes was analyzed. Hub genes with |correlation coefficient|> 0.45 and p-value < 0.05 were used as characteristic biomarkers. Finally, the logistic regression model is used to verify the three markers in the training set and verification set (GSE97358 and GSE225336). A total of 635 DEGs were identified. Functional enrichment analysis shows that inflammation and immune response, extracellular matrix and structural remodeling play an important role in the pathological mechanism of MF. Immune cell infiltration analysis showed that immune cells (Plasma cells, Eosinophils, Chondrocytes and Th2 cells) significantly changed in MF pathological conditions. In PPI network analysis, IL1ß, TTN, PTPRC, IGF1, ALDH1A1, CYP26A1, ALDH1A3, MYH11, CSF1R and CD80 were identified as hub genes, among which IL1ß, CYP26A1 and GNG2 were regarded as immune-related characteristic markers. The AUC scores of the three biomarkers are all above 0.65, which proves that they have a good discrimination effect in MF. In this study, three immune-related genes were identified as diagnostic biomarkers of MF, which provided a new perspective for exploring the molecular mechanism of MF. This study takes a comprehensive approach to understanding the intricate relationship between myocardial fibrosis and immune metabolism. By identifying key immune-related biomarkers, this study not only reveals the molecular basis of myocardial fibrosis but also paves the way for the development of novel diagnostic tools and therapeutic strategies. These findings are critical for improving patient prognosis and may have broader implications for studying and treating other cardiovascular diseases associated with immune dysregulation.

Utility of Cardiac Magnetic Resonance in Assessing Arrhythmic Risk in Patients With Nonischemic Cardiomyopathy Undergoing Biventricular Pacing.

BACKGROUND: Nonischemic cardiomyopathy (NICM) is responsible for approximately one-third of heart failure and is associated with significant morbidity and mortality. Recent data suggested the lack of mortality reduction from adding a defibrillator to cardiac resynchronization therapy (CRT) in all patients with NICM. Myocardial fibrosis detected by cardiac magnetic resonance late gadolinium enhancement (CMR-LGE) can help risk stratify patients who would benefit from adding a defibrillator to CRT in this patient population. OBJECTIVES: We aim to assess the relationship between the presence of myocardial fibrosis detected by CMR-LGE and the rate of major arrhythmic events (MAE) that included sustained ventricular tachycardia (VT), appropriate cardiac resynchronization therapy-defibrillator (CRT-D) intervention, ventricular fibrillation (VF), and sudden cardiac death (SCD) in patients with NICM undergoing CRT and to compare all-cause mortality and heart failure improvement between patients receiving cardiac resynchronization therapy-pacing (CRT-P) versus those receiving CRT-D based on the presence of myocardial fibrosis. METHODS: All consecutive patients with NICM satisfying a guideline-directed indication for CRT implantation were included in the study after excluding patients who refused to consent, patients with acute decompensated heart failure, and those contraindicated for a cardiac magnetic resonance (CMR). Patients were divided into two groups based on the presence of fibrosis in cardiac MRI: the LGE/CRT-D group and the No LGE/CRT-P group. They were then followed for 1 year. RESULTS: Sixty patients were enrolled. Sixteen patients (26.6%) developed MAE during the study duration, among those patients, seven had myocardial fibrosis (receiving CRT-D as per protocol), while nine had no myocardial fibrosis (receiving CRT-P as per protocol), (41.2% vs. 20.9%, p = 0.045). The presence of CMR-LGE, regardless of the extent and distribution, predicted MAE with an odds ratio of 2.6 (CI = 1.78-8.9, p = 0.04). The presence of ≥7.5% of myocardial fibrosis by CMR was associated with 54% sensitivity and 100% specificity for MAE in the study population. All-cause mortality was significantly higher in the No LGE/CRT-P group versus the LGE/CRT-D group (15 [34.9%] vs. 2 [11.8%], p = 0.076). CONCLUSION: In patients with NICM candidates for biventricular pacing, the presence of LGE on CMR, irrespective of the extent or segmental pattern, is independently associated with an MAE and is associated with worse heart failure outcomes. However, the absence of LGE did not rule out MAE, and implanting CRT-P based on lack of fibrosis may result in higher all-cause mortality.

[Mechanism of Linggui Zhugan Decoction in inhibiting myocardial fibrosis by regulating Wnt/ß-catenin pathway].

This study aimed to investigate the regulatory mechanism of Linggui Zhugan Decoction(LGZGD)-medicated serum on the fibrosis of cardiac fibroblasts(CFs) and the protein expression of the Wnt/ß-catenin signaling pathway. Blank serum and LGZGD-medicated serum were prepared, and primary CFs were isolated and cultured using trypsin-collagenase digestion and differential adhesion method. Immunofluorescence labeling was used to identify primary CFs. Cells were divided into normal control group, model group, 20% blank serum group, and 5%, 10%, and 20% LGZGD-medicated serum groups. Except for the normal control group, all other groups were stimulated with hydrogen peroxide(H_2O_2) after pretreatment with 20% blank serum or 5%, 10%, 20% LGZGD-medicated serum for 12 hours to establish a model of fibrosis in primary CFs. Scratch healing assay was used to observe cell migration ability. ELISA was used to detect the content of collagen type Ⅰ(Col Ⅰ) and type Ⅲ(Col Ⅲ). Western blot was used to detect the protein expression of α-smooth muscle actin(α-SMA), Wnt1, glycogen synthase kinase 3ß(GSK-3ß), phosphorylated GSK-3ß(p-GSK-3ß), ß-catenin, and nuclear ß-catenin. RT-qPCR was used to detect the gene expression of ß-catenin and matrix metalloproteinase 9(MMP9), and immunofluorescence technique was used to detect the expression and localization of key proteins α-SMA and ß-catenin. CFs with Wnt1 overexpression were prepared and treated with H_2O_2. The following groups were set up: normal control group, model group, 20% LGZGD-medicated serum group, empty plasmid+20% LGZGD-medicated serum group, and Wnt1 overexpression+20% LGZGD-medicated serum group. ELISA was used to detect the content and ratio of Col Ⅰ and Col Ⅲ. Western blot was used to detect the protein expression of α-SMA, Wnt1, GSK-3ß, p-GSK-3ß, ß-catenin, and nuclear ß-catenin. RT-qPCR was used to detect the gene expression of ß-catenin and MMP9. Immunofluorescence staining showed that CFs expressed Vimentin positively, appearing green, with blue nuclei and purity greater than 90%, which were identified as primary CFs. RESULTS:: showed that compared with the normal control group, CFs in the model group had enhanced healing rate, increased content of Col Ⅰ and Col Ⅲ, increased ratio of Col Ⅰ/Col Ⅲ, upregulated protein expression of α-SMA, Wnt1, p-GSK-3ß, ß-catenin, nuclear ß-catenin, decreased GSK-3ß expression, elevated mRNA expression of ß-catenin and MMP9, and enhanced fluorescence intensity and expression of ß-catenin and α-SMA. Compared with the model group, 5%, 10%, 20% LGZGD-medicated serum significantly inhibited cell migration ability, reduced the content of Col Ⅰ and Col Ⅲ, decreased ratio of Col Ⅰ/Col Ⅲ, downregulated protein expression of α-SMA, Wnt1, p-GSK-3ß, ß-catenin, nuclear ß-catenin, increased GSK-3ß expression, decreased mRNA expression of ß-catenin and MMP9, and reduced fluorescence intensity and expression of ß-catenin and α-SMA. Compared with the empty plasmid+20% LGZGD-medicated serum group, the effect of LGZGD-medicated serum was significantly reversed after overexpression of Wnt1. LGZGD can reduce excessive deposition of collagen fibers, inhibit excessive proliferation of fibroblasts, and improve the process of myocardial fibrosis. The improvement of myocardial fibrosis by LGZGD is related to the regulation of the Wnt/ß-catenin pathway, reduction of collagen deposition, and protection of myocardial cells.

[Effect of Linggui Zhugan Decoction on myocardial fibrosis and Lats1/Yap signaling pathway in mice after myocardial infraction].

This study aims to investigate the effects of Linggui Zhugan Decoction(LGZGD) on myocardial fibrosis(MF) and the Lats1/Yap signaling pathway in mice after myocardial infarction(MI), exploring its role and mechanism in inhibiting MF. The MI-induced ischemic mouse model was established by left anterior descending coronary artery ligation, followed by continuous intervention for six weeks. Doppler ultrasound imaging-system of small animals was used to detect left ventricular ejection fraction(LVEF), left ventricular fractional shortening(LVFS), left ventricular internal diameter at end-systole(LVIDs), and left ventricular internal diameter at end-diastole(LVIDd). Pathological changes in myocardial tissue were observed by HE and Masson staining. Serum levels of creatine kinase isoenzyme MB(CK-MB) and lactate dehydrogenase(LDH) were detected by using ELISA. Myocardial tissue mRNA levels of Lats1, Yap, and connective tissue growth factor(CTGF) were determined by RT-qPCR. Protein expression of alpha-smooth muscle actin(α-SMA), collagen Ⅰ(Col Ⅰ), collagen Ⅲ(Col Ⅲ), tissue inhibitor of metal protease 1(TIMP1), matrix metallopeptidase 2(MMP2), Yap, p-Yap, and n-Yap was determined by Western blot. Compared with the sham group, the model group showed significantly decreased LVEF and LVFS levels, increased LVIDd and LVIDs levels(P<0.01), disordered arrangement of myocardial cells, partial fracture of myocardial fibers, and massive deposition of collagen fibers. Moreover, serum levels of CK-MB and LDH were significantly increased(P<0.01), while myocardial tissue mRNA levels of Lats1 were significantly decreased(P<0.01), and mRNA levels of Yap and CTGF were significantly increased(P<0.01). Protein expression of α-SMA, Col Ⅰ, Col Ⅲ, MMP2, Yap, and n-Yap was significantly increased(P<0.01), while protein expression of Lats1, TIMP1, p-Yap, and the ratio of p-Yap/Yap were significantly decreased(P<0.01). Compared with the model group, after intervention with LGZGD(9.36 g·kg~(-1)), mice showed significantly increased LVEF and LVFS levels, decreased LVIDd and LVIDs levels(P<0.01), more orderly arrangement of myocardial cells, significantly reduced myocardial fiber fracture and collagen fiber deposition. Serum levels of CK-MB and LDH were significantly decreased(P<0.01), while myocardial tissue mRNA levels of Lats1 were significantly increased(P<0.01), and mRNA levels of Yap and CTGF were significantly decreased(P<0.01). Protein expression of α-SMA, Col Ⅰ, Col Ⅲ, MMP2, Yap, and n-Yap was significantly decreased(P<0.01), while protein expression of Lats1, TIMP1, p-Yap, and the ratio of p-Yap/Yap were significantly increased(P<0.01). LGZGD can inhibit MF in mice after MI and improve mouse cardiac function, which is closely related to the activation of the Lats1/Yap signaling pathway.

An Intriguing Case of Myocardial Deposits.

Cardiac calcification refers to calcium deposits in the coronary arteries, heart valves, pericardium, or myocardium. Calcium deposition within the myocardium is unique and can be secondary to metastatic or dystrophic calcification. Both forms are linked to cardiac abnormalities and poor prognosis. The most common causes include myocardial infarction, sepsis, myocarditis, renal failure, and hyperparathyroidism. Here, we report the case of a 74-year-old male who was found to have gallbladder adenocarcinoma with subsequent preoperative workup indicating possible metastases to the myocardium. With the use of multimodality imaging, particularly cardiac MRI, the differentiation between metastatic disease and intramyocardial calcification was made. The case aims to highlight the complexity of diagnosing and managing myocardial calcifications and underscores the need for further research into their etiology and implications.

Unveiling the Mechanism of Protective Effects of Tanshinone as a New Fighter Against Cardiovascular Diseases: A Systematic Review.

Tanshinone, a natural compound found in the roots of Salvia miltiorrhiza, has been shown to possess various pharmacological properties, including anti-inflammatory, antioxidant, and cardiovascular protective effects. This article aims to review the literature on the cardiovascular protective effects of tanshinone and its underlying mechanisms. Tanshinone has been demonstrated to improve cardiac function, reduce oxidative stress, and inhibit inflammation in various animal models of cardiovascular diseases. Additionally, it has been shown to regulate multiple signaling pathways involved in the pathogenesis of cardiovascular diseases, such as the PI3K/AKT, MAPK, and NF-κB pathways. Clinical studies have also suggested that tanshinone may have therapeutic potential for treating cardiovascular diseases. In conclusion, tanshinone has emerged as a promising natural compound with significant cardiovascular protective effects, and further research is warranted to explore its potential clinical applications.

Unveiling the role of TRPA1 in cardiovascular health and disease: a mini review.

The transient receptor potential ankyrin 1 (TRPA1) ion channel has emerged as significant regulators of cardiovascular physiology and pathology. TRPA1 is a non-selective cation channel permeable to calcium ions. A unique feature of the channel is its function as a sensor of various temperature, chemical and mechanical stimuli, while it can also be activated by endogenous inflammatory mediators and reactive oxygen species. Over the last two decades, much progress has been made in illuminating the role of TRPA1 in the regulation of cardiovascular physiology and pathophysiology in addition to its important function in pain sensation. This review provides a comprehensive analysis of recent studies investigating the involvement of TRPA1 channels in various cardiovascular diseases, including myocardial infarction, ischemia-reperfusion injury, myocardial fibrosis, and response to environmental toxins. We discuss the diverse roles of TRPA1 channels in cardiac pathology and highlight their potential as therapeutic targets for cardiovascular disorders. Moreover, we explore the challenges and opportunities linked with targeting TRPA1 channels for treating cardiovascular diseases, alongside future research directions.

Modulation of the Cardiovascular Risk in Type 1 Diabetic Rats by Endurance Training in Combination with the Prebiotic Xylooligosaccharide.

Diabetic cardiomyopathy is a major etiological factor in heart failure in diabetic patients, characterized by mitochondrial oxidative metabolism dysfunction, myocardial fibrosis, and marked glycogen elevation. The aim of the present study is to evaluate the effect of endurance training and prebiotic xylooligosaccharide (XOS) on the activity of key oxidative enzymes, myocardial collagen, and glycogen distribution as well as some serum biochemical risk markers in streptozotocin-induced type 1 diabetic rats. Male Wistar rats (n = 36) were divided into four diabetic groups (n = 9): sedentary diabetic rats on a normal diet (SDN), trained diabetic rats on a normal diet (TDN), trained diabetic rats on a normal diet with an XOS supplement (TD-XOS), and sedentary diabetic rats with an XOS supplement (SD-XOS). The results show that aerobic training managed to increase the enzyme activity of respiratory Complex I and II and the lactate dehydrogenase in the cardiomyocytes of the diabetic rats. Furthermore, the combination of exercise and XOS significantly decreased the collagen and glycogen content. No significant effects on blood pressure, heart rate or markers of inflammation were detected. These results demonstrate the beneficial effects of exercise, alone or in combination with XOS, on the cardiac mitochondrial enzymology and histopathology of diabetic rats.

Ischemic-Preconditioning Induced Serum Exosomal miR-133a-3p Improved Post-Myocardial Infarction Repair via Targeting LTBP1 and PPP2CA.

Background: Ischemic preconditioning-induced serum exosomes (IPC-exo) protected rat heart against myocardial ischemia/reperfusion injury. However, whether IPC-exo regulate replacement fibrosis after myocardial infarction (MI) and the underlying mechanisms remain unclear. MicroRNAs (miRs) are important cargos of exosomes and play an essential role in cardioprotection. We aim to investigate whether IPC-exo regulate post-MI replacement fibrosis by transferring cardioprotective miRs and its action mechanism. Methods: Exosomes obtained from serum of adult rats in control (Con-exo) and IPC groups were identified and analyzed, subsequently intracardially injected into MI rats following ligation. Their miRs profiles were identified using high-throughput miR sequencing to identify target miRs for bioinformatics analysis. Luciferase reporter assays confirmed target genes of selected miRs. IPC-exo transfected with selected miRs antagomir or NC were intracardially administered to MI rats post-ligation. Cardiac function and degree of replacement fibrosis were detected 4 weeks post-MI. Results: IPC-exo exerted cardioprotective effects against excessive replacement fibrosis. MiR sequencing and RT-qPCR identified miR-133a-3p as most significantly different between IPC-exo and Con-exo. MiR-133a-3p directly targeted latent transforming growth factor beta binding protein 1 (LTBP1) and protein phosphatase 2, catalytic subunit, alpha isozyme (PPP2CA). KEGG analysis showed that transforming growth factor-ß (TGF-ß) was one of the most enriched signaling pathways with miR-133a-3p. Comparing to injection of IPC-exo transfected with miR-133a-3p antagomir NC, injecting IPC-exo transfected with miR-133a-3p antagomir abolished protective effects of IPC-exo on declining excessive replacement fibrosis and cardiac function enhancement, while increasing the messenger RNA and protein expression of LTBP1, PPP2CA, and TGF-ß1in MI rats. Conclusion: IPC-exo inhibit excessive replacement fibrosis and improve cardiac function post-MI by transferring miR-133a-3p, the mechanism is associated with directly targeting LTBP1 and PPP2CA, and indirectly regulating TGF-ß pathway in rats. Our finding provides potential therapeutic effect of IPC-induced exosomal miR-133a-3p for cardiac repair.

Atlas of Regional Left Ventricular Scar in Nonischemic Cardiomyopathies: Substrates and Etiologies.

Most acquired and inherited cardiomyopathies are characterized by regional left ventricular involvement and nonischemic myocardial scars, often with a disease-specific pattern. Irrespective of the etiology and pathophysiological mechanisms, myocardial disorders are invariably associated with cardiac fibrosis, which contributes to dysfunction and electrical instability. Accordingly, cardiac magnetic resonance plays a central role in the diagnostic work-up and prognostic risk stratification of cardiomyopathies, particularly with the increasing correlation between genetic background and specific disease phenotype. Starting from pattern and distribution of myocardial fibrosis at cardiac magnetic resonance, we provide a practical regional atlas of nonischemic myocardial scar to guide the diagnostic approach to nonischemic cardiomyopathies.

Exploring the role of iNOS in HFpEF-Related myocardial fibrosis: Involvement of PTEN-PI3K/AKT signaling pathway.

BACKGROUND: Heart failure with preserved ejection fraction (HFpEF) is a challenging condition to treat with myocardial fibrosis being a pivotal pathological component. Previous studies have suggested a role for inducible nitric oxide synthase (iNOS) in the progression of this condition, but the precise mechanisms remain unclear. This study aimed to investigate the role of iNOS in HFpEF-related myocardial fibrosis and identify potential therapeutic targets. METHODS: A 'two-hit' mouse model of HFpEF was established, and echocardiography, histopathology and biochemical analyses were performed. In vitro experiments were conducted in mouse cardiac fibroblasts, with iNOS overexpression and application of iNOS or phosphatidylinositol 3 kinase (PI3K) inhibitors. The iNOS-S-nitrosylated phosphatase and TENsin homolog (SNO-PTEN)-phosphorylated-protein kinase B (p-AKT) pathway was investigated, along with the effects on fibrotic markers and cell proliferation and migration. RESULTS: HFpEF mice exhibited significant cardiac dysfunction and fibrosis, with increased expression of iNOS, SNO-PTEN, and p-AKT, indicative of the activation of the iNOS-SNO-PTEN-p-AKT pathway. iNOS overexpression in mouse cardiac fibroblasts led to increased SNO-PTEN, decreased PTEN, activated phosphorylated PI3K (p-PI3K) and p-AKT, and enhanced cell proliferation and migration, as well as increased collagen I and III expression. The use of an iNOS inhibitor (L-NIL) or a PI3K inhibitor (LY294002) partially reversed these changes. CONCLUSION: Our findings suggest that the iNOS-SNO-PTEN-p-AKT pathway may play a crucial role in HFpEF-related myocardial fibrosis, with iNOS and PI3K inhibitors offering potential therapeutic benefits. These insights may pave the way for the development of effective drug therapies for HFpEF.

Free-Breathing Non-Contrast T1ρ Dispersion MRI of Myocardial Interstitial Fibrosis in Comparison with Extracellular Volume Fraction.

BACKGROUND: Myocardial fibrosis is a common feature in various cardiac diseases. It causes adverse cardiac remodeling and is associated with poor clinical outcomes. Late gadolinium enhancement (LGE) and extracellular volume fraction (ECV) are the standard MRI techniques for detecting focal and diffuse myocardial fibrosis. However, these contrast-enhanced techniques require the administration of gadolinium contrast agents, which is not applicable to patients with gadolinium contraindications. To eliminate the need of contrast agents, we develop and apply an endogenous free-breathing T1ρ dispersion imaging technique (FB-MultiMap) for diagnosing diffuse myocardial fibrosis in a cohort with suspected cardiomyopathies. METHODS: The proposed FB-MultiMap technique, enabling T2, T1ρ and their difference (myocardial fibrosis index, mFI) quantification in a single scan was developed in phantoms and 15 healthy subjects. In the clinical study, 55 patients with suspected cardiomyopathies were imaged using FB-MultiMap, conventional native T1 mapping, LGE, and ECV imaging. The accuracy of the endogenous parameters for predicting increased ECV was evaluated using receiver operating characteristic (ROC) curve analysis. In addition, the correlation of native T1, T1ρ, and mFI with ECV was respectively assessed using Pearson correlation coefficients. RESULTS: FB-MultiMap showed a good agreement with conventional separate breath-hold mapping techniques in phantoms and healthy subjects. Considering all the patients, T1ρ was more accurate than mFI and native T1 for predicting increased ECV, with area under the curve (AUC) values of 0.91, 0.79 and 0.75, respectively, and showed stronger correlation with ECV (correlation coefficient r: 0.72 vs. 0.52 vs. 0.40). In the subset of 47 patients with normal T2 values, the diagnostic performance of mFI was significantly strengthened (AUC=0.90, r=0.83), outperforming T1ρ and native T1. CONCLUSION: The proposed free-breathing T1ρ dispersion imaging technique enabling simultaneous quantification of T2, T1ρ and mFI in a single scan has shown great potential for diagnosing diffuse myocardial fibrosis in patients with complex cardiomyopathies without contrast agents.

Effect of fibroblasts small- conductance Ca2+ -activated potassium channel subtype 2 (SK2) on myocardial fibrosis in pressure overload mouse.

Studies have shown that Small conductance Ca2 + -activated K+ (SK) channel are expressed in fibroblasts. We aimed to determine the expression of SK2 channels in cardiac fibroblasts during myocardial hypertrophy and investigate its relationship with fibrotic remodeling. Myocardial hypertrophy and fibrotic remodeling induced by transverse aortic constriction (TAC) were assessed by echocardiography, Masson's trichrome staining and Western blot. Knockdown and overexpression of the SK2 protein were used to assess relationship between SK2 expression in fibroblasts and myocardial fibrosis. There is a positive correlation between myocardial fibrosis and SK2 channel protein expression during the development of myocardial hypertrophy. The differentiation and secretion of fibroblasts in mice with cardiac hypertrophy are enhanced, and the expression of SK2 channel protein is increased. Manipulating SK2 levels in fibroblasts can either promote or inhibit their differentiation and secretory function. Knocking down SK2 reduces the up-regulation of TGF ß1, p-Smad2/3/GAPDH, p-p38/GAPDH, p-ERK1/2/GAPDH, and p-JNK/GAPDH proteins induced by Ang II in cardiac fibroblasts without significantly affecting total protein levels. AAV9-SK2-RNAi injection in mice improves cardiac function. Collectively, our study suggests that the expression of the SK2 channel is significantly increased in fibroblasts of mice with myocardial hypertrophy, potentially impacting myocardial fibrosis remodeling via the TGF-ß signaling pathway.

Identification of macrophage driver genes in fibrosis caused by different heart diseases based on omics integration.

BACKGROUND: Myocardial fibrosis, a hallmark of heart disease, is closely associated with macrophages, yet the genetic pathophysiology remains incompletely understood. In this study, we utilized integrated single-cell transcriptomics and bulk RNA-seq analysis to investigate the relationship between macrophages and myocardial fibrosis across omics integration. METHODS: We examined and curated existing single-cell data from dilated cardiomyopathy (DCM), ischemic cardiomyopathy (ICM), myocardial infarction (MI), and heart failure (HF), and analyzed the integrated data using cell communication, transcription factor identification, high dimensional weighted gene co-expression network analysis (hdWGCNA), and functional enrichment to elucidate the drivers of macrophage polarization and the macrophage-to-myofibroblast transition (MMT). Additionally, we assessed the accuracy of single-cell data from the perspective of driving factors, cell typing, anti-fibrosis performance of left ventricular assist device (LVAD). Candidate drugs were screened using L1000FWD. RESULTS: All four heart diseases exhibit myocardial fibrosis, with only MI showing an increase in macrophage proportions. Macrophages participate in myocardial fibrosis through various fibrogenic molecules, especially evident in DCM and MI. Abnormal RNA metabolism and dysregulated transcription are significant drivers of macrophage-mediated fibrosis. Furthermore, profibrotic macrophages exhibit M1 polarization and increased MMT. In HF patients, those responding to LVAD therapy showed a significant decrease in driver gene expression, M1 polarization, and MMT. Drug repurposing identified cinobufagin as a potential therapeutic agent. CONCLUSION: Using integrated single-cell transcriptomics, we identified the drivers of macrophage-mediated myocardial fibrosis in four heart diseases and confirmed the therapeutic effect of LVAD on improving HF with single-cell accuracy, providing novel insights into the diagnosis and treatment of myocardial fibrosis.