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.

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.

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.

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.

Wnt1 gene expression in the heart left ventricle as a response to the various durations of the intensive exercise: An experimental study.

Objective. Myocardial fibrosis is a devastating condition causing millions of deaths yearly. Several factors, such as aging, cause myocardial fibrosis. The Wnt/ß-catenin pathway is one of the critical intracellular signaling for the development of cardiac fibrosis. Molecular and cellular mechanism of myocardial fibrosis induced by intensive exercise is not well-understood. The current study evaluates the effects of short- and long-term intensive exercise on the Wnt1 gene expression in a heart left ventricle in an animal model. Methods. Twenty-one male Wistar rats (mean weight 250±50 g) were divided into three groups (n=7): 1) control group (C); 2) short-term regular intensive exercise group (S-RIE, high-intensity exercise for one month six days weekly for 60 min with speed of 35 m/min), and 3) long-term regular intensive exercise group (L-RIE, high-intensity exercise for six months six days daily for 60 min with speed of 35 m/min). The heart left ventricle was isolated at the end of the experiment, and the relative gene expression of the Wnt1 gene was measured by the Real-Time PCR. Results. The L-RIE group showed a significant increase in the Wnt1 expression compared to the S-RIE and the control group. Although no difference was observed in the Wnt1 mRNA level in the S-RIE group compared to the control group, Wnt1 mRNA level increased in the L-RIE group compared to the S-RIE group. Conclusion. The exercise duration was of a great importance in the Wnt1 gene expression. Regular intensive exercise may be involved in the formation of the myocardial fibrosis by increasing the expression of the Wnt1 gene.

SGK3 deficiency in macrophages suppresses angiotensin II-induced cardiac remodeling via regulating Ndufa13-mediated mitochondrial oxidative stress.

Infiltration of monocyte-derived macrophages plays a crucial role in cardiac remodeling and dysfunction. The serum and glucocorticoid-inducible protein kinase 3 (SGK3) is a downstream factor of PI3K signaling, regulating various biological processes via an AKT-independent signaling pathway. SGK3 has been implicated in cardiac remodeling. However, the contribution of macrophagic SGK3 to hypertensive cardiac remodeling remains unclear. A cardiac remodeling model was established by angiotensin II (Ang II) infusion in SGK3-Lyz2-CRE (f/f, +) and wild-type mice to assess the function of macrophagic SGK3. Additionally, a co-culture system of SGK3-deficient or wild-type macrophages and neonatal rat cardiomyocytes (CMs) or neonatal rat fibroblasts (CFs) was established to evaluate the effects of SGK3 and the underlying mechanisms. SGK3 levels were significantly elevated in both peripheral blood mononuclear cells and serum from patients with heart failure. Macrophage SGK3 deficiency attenuated Ang II-induced macrophage infiltration, myocardial hypertrophy, myocardial fibrosis, and mitochondrial oxidative stress. RNA sequencing suggested Ndufa13 as the candidate gene in the effect of SGK3 on Ang II-induced cardiac remolding. Downregulation of Ndufa13 in CMs and CFs prevented the suppression of cardiac remodeling caused by SGK3 deficiency in macrophages. Mechanistically, the absence of SGK3 led to a reduction in IL-1ß secretion by inhibiting the NLRP3/Caspase-1/IL-1ß pathway in macrophages, consequently suppressing upregulated Ndufa13 expression and mitochondrial oxidative stress in CMs and CFs. This study provides new evidence that SGK3 is a potent contributor to the pathogenesis of hypertensive cardiac remodeling, and targeting SGK3 in macrophages may serve as a potential therapy for cardiac remodeling.

Computer-Assisted Algorithm for Quantification of Fibrosis by Native Cardiac CT: A Pilot Study.

Background/Objectives: Recent advances in artificial intelligence, particularly in cardiac imaging, can potentially enhance patients' diagnosis and prognosis and identify novel imaging markers. We propose an automated, computer-aided algorithm utilizing native cardiac computed tomography (CT) imaging to identify myocardial fibrosis. This study aims to evaluate its performance compared to CMR markers of fibrosis in a cohort of patients diagnosed with breast cancer. Methods: The study included patients diagnosed with early HER2+ breast cancer, who presented LV dysfunction (LVEF < 50%) and myocardial fibrosis detected on CMR at the time of diagnosis. The patients were also evaluated by cardiac CT, and the extracted images were processed for the implementation of the automatic, computer-assisted algorithm, which marked as fibrosis every pixel that fell within the range of 60-90 HU. The percentage of pixels with fibrosis was subsequently compared with CMR parameters. Results: A total of eight patients (n = 8) were included in the study. High positive correlations between the algorithm's result and the ECV fraction (r = 0.59, p = 0.126) and native T1 (r = 0.6, p = 0.112) were observed, and a very high positive correlation with LGE of the LV(g) and the LV-LGE/LV mass percentage (r = 0.77, p = 0.025; r = 0.81, p = 0.015). A very high negative correlation was found with GLS (r = -0.77, p = 0.026). The algorithm presented an intraclass correlation coefficient of 1 (95% CI 0.99-1), p < 0.001. Conclusions: The present pilot study proposes a novel promising imaging marker for myocardial fibrosis, generated by an automatic algorithm based on native cardiac CT images.

Left Ventricular Fibrosis by Cardiac Magnetic Resonance Tissue Characterization in Chronic Mitral Regurgitation Patients.

Background: Left ventricular remodeling in chronic mitral regurgitation (MR) encompasses two types of myocardial fibrosis: replacement fibrosis, identified by late gadolinium enhancement (LGE), and diffuse interstitial fibrosis, assessed by pre- and postcontrast T1 mapping techniques. These may explain irreversible LV dysfunction after MR correction. We aimed to assess the presence of myocardial fibrosis in patients with moderate and severe MR with no criteria for surgery versus mild MR controls. Methods: We enrolled 137 patients with chronic primary MR and 130 controls; all underwent cardiac magnetic resonance, and were followed up in a median of 2.9 years to assess mortality and the need for mitral valve replacement. Results: Patients in the study group displayed significantly higher degrees of LGE (28.4% vs 7.69%, p < 0.05), higher native T1 values (1167 ± 58.5 versus 971 ± 51.4 (p < 0.05)), and higher extracellular volumes compared to controls (32.3% ± 3.5 versus 23.9 ± 2.2, (p < 0.05)). The composite outcome occurred in 28 patients in the study group (20.4%), and significantly higher with LGE+ (78.5%). Replacement fibrosis (HR = 1.83, 95% CI, p < 0.01) and interstitial fibrosis (HR = 1.61, 95% CI, p < 0.01) were independent predictors for the composite outcome. Conclusions: Patients with moderate and severe MR with no criteria for surgery still exhibit a significant degree of both replacement and interstitial fibrosis, with prognostic implications.

[Effects of Luhong Yixin Granules on myocardial fibrosis in heart failure rats based on TGF-ß1/Smads signaling pathway].

To investigate the effects of Luhong Yixin Granules on myocardial fibrosis in rats with heart failure and its possible mechanism, a total of 60 male Wistar rats were randomly divided into the control group, model group, and low-, medium-and high-dose Luhong Yixin Granules groups, with 12 rats in each group. Except for those in the control group, rats in the other groups were induced by intraperitoneal injection of doxorubicin(DOX) into a rat model. After the Luhong Yixin Granules were dissolved in the same amount of normal saline, they were given by gavage at low, medium and high doses(2.8, 5.6, 11.2 g·kg~(-1)·d~(-1)), and the control group and the model group were given the same amount of normal saline by gavage for 40 days. After the end of dosing, echocardiography was used to measure left ventricular ejection fraction(LVEF) and left ventricular fractional shortening(LVFS). Rat body weight(BW) and heart weight(HW) were calculated as HW/BW. Enzyme-linked immunosorbent assay was used to measure the levels of interleukin-6(IL-6), interleukin-17(IL-17), tumor necrosis factor-α(TNF-α), transforming growth factor-ß1(TGF-ß1), growth stimulation expressed gene 2 protein(ST2), N-terminal pro-B-type natriuretic peptide(NT-proBNP), galectin-3(Gal-3) and creatine kinase isoenzyme(CK-MB) in serum. Hematoxylin-eosin(HE) staining and Masson staining were used to observe the pathological morphology of myocardial tissue. Western blot and quantitative real-time polymerase chain reaction were used to detect the protein and mRNA expression levels of IL-6, IL-17, TNF-α, TGF-ß1, Smad3, Smad7, α-smooth muscle actin(α-SMA), and collagen Ⅰ(COL-Ⅰ), respectively. RESULTS:: showed that compared with those in the control group, LVEF, LVFS, and HW/BW in the model group were decreased(P<0.05), and the levels of IL-6, IL-17, TNF-α, TGF-ß1, ST2, NT-proBNP, Gal-3, and CK-MB were increased(P<0.05). HE staining showed inflammatory changes in myocardial tissue; Masson staining showed decreases in the cross-sectional area and ventricular cavity area of the heart, and myocardial fibrosis of varying degrees(P<0.05). The protein and mRNA expression of IL-6, IL-17, TNF-α, TGF-ß1, Smad3, α-SMA, and COL-Ⅰ were increased(P<0.05), and the protein and mRNA expression of Smad7 protein was decreased(P<0.01). Compared with those in the model group, LVEF, LVFS and HW/BW of the low-, medium-and high-dose Luhong Yixin Granules groups were increased(P<0.05), and the levels of IL-6, IL-17, TNF-α, TGF-ß1, ST2, NT-proBNP, Gal-3 and CK-MB were decreased(P<0.05). HE staining showed gradually reduced inflammatory changes of myocardial tissue, and Masson staining showed increased cross-sectional area and ventricular cavity area of the heart and decreased area of myocardial fibrosis(P<0.05). The protein and mRNA expression levels of IL-6, IL-17, TNF-α, TGF-ß1, Smad3, α-SMA, and COL-Ⅰ were decreased(P<0.05), while the protein and mRNA expression levels of Smad7 were increased(P<0.05). Luhong Yixin Granules may be of great value in the treatment of heart failure by regulating the TGF-ß1/Smads signaling pathway, inhibiting the expression of inflammation-related proteins, reducing the deposition of extracellular matrix, and alleviating myocardial fibrosis.

Targeting SOCS2 alleviates myocardial fibrosis by reducing nuclear translocation of ß-catenin.

BACKGROUND: Myocardial fibrosis is an important pathological feature of dilated cardiomyopathy (DCM). The roles of SOCS2 in fibrosis of different organs are controversial. Herein, we investigated the function and potential mechanism of SOCS2 in myocardial fibrosis. METHODS: Bioinformatics, immunohistochemistry (IHC), immunofluorescence (IF), western blot (WB), real-time fluorescence quantitative PCR (qPCR), rat primary myocardial fibroblasts (rCFs) culture, doxorubicin (DOX) induced mouse dilated cardiomyopathy (DCM) model, and in vivo adeno-associated virus (AAV) infection were used to explore the role of SOCS2 in DCM. RESULTS: Bioinformatics analysis showed that SOCS2 was positively correlated with fibrosis related factors. SOCS2 was significantly upregulated in patients and mice with DCM. In vivo experiments showed that targeted inhibition of cardiac SOCS2 could improve mouse cardiac function and alleviate myocardial fibrosis. Further research demonstrated that SOCS2 promoted the transformation of myofibroblasts. Knockdown of SOCS2 reduced the nuclear localization of ß-catenin, which inhibited the fibrogenic effect of Wnt/ß-catenin pathway. In addition, bioinformatics analysis suggested that lymphoid enhancer binding factor 1 (LEF1) was significantly positively correlated with SOCS2. Finally, dual luciferase assays demonstrated that LEF1 could bind to the promoter region of SOCS2, thereby mediating its transcriptional activation. CONCLUSION: SOCS2 could activate the Wnt/ß-catenin by regulating the nuclear translocation of ß-catenin, which induces the transcriptional activation of SOCS2. Overall, these results indicated a positive feedback activation phenomenon between SOCS2, ß-catenin and LEF1 in DCM. These results suggested that inhibition of SOCS2 could effectively alleviate the progression of myocardial fibrosis and improve cardiac function.

The influence of endurance exercise training on myocardial fibrosis and arrhythmogenesis in a coxsackievirus B3 myocarditis mouse model.

Nonischaemic myocardial fibrosis is associated with cardiac dysfunction, malignant arrhythmias and sudden cardiac death. In the absence of a specific aetiology, its finding as late gadolinium enhancement (LGE) on cardiac magnetic resonance imaging is often attributed to preceding viral myocarditis. Athletes presenting with ventricular arrhythmias often have nonischaemic LGE. Previous studies have demonstrated an adverse effect of exercise on the course of acute viral myocarditis. In this study, we have investigated, for the first time, the impact of endurance training on longer-term outcomes such as myocardial fibrosis and arrhythmogenicity in a murine coxsackievirus B3 (CVB)-induced myocarditis model. Male C57BL/6J mice (n = 72) were randomly assigned to 8 weeks of forced treadmill running (EEX) or no exercise (SED). Myocarditis was induced 2 weeks later by a single intraperitoneal injection with CVB, versus vehicle in the controls (PBS). In a separate study, mice (n = 30) were subjected to pretraining for 13 weeks (preEEX), without continuation of exercise during myocarditis. Overall, continuation of exercise resulted in a milder clinical course of viral disease, with less weight loss and better preserved running capacity. CVB-EEX and preEEX-CVB mice tended to have a lower mortality rate. At sacrifice (i.e. 6 weeks after inoculation), the majority of virus was cleared from the heart. Histological assessment demonstrated prominent myocardial inflammatory infiltration and cardiomyocyte loss in both CVB groups. Inflammatory lesions in the CVB-EEX group contained higher numbers of pro-inflammatory cells (iNOS-reactive macrophages and CD8+ T lymphocytes) compared to these in CVB-SED. Treadmill running during myocarditis increased interstitial fibrosis [82.4% (CVB-EEX) vs. 56.3% (CVB-SED); P = 0.049]. Additionally, perivascular and/or interstitial fibrosis with extensive distribution was more likely to occur with exercise [64.7% and 64.7% (CVB-EEX) vs. 50% and 31.3% (CVB-SED); P = 0.048]. There was a numerical, but not significant, increase in the number of scars per cross-section (1.9 vs. 1.2; P = 0.195), with similar scar distribution and histological appearance in CVB-EEX and CVB-SED. In vivo electrophysiology studies did not induce sustained monomorphic ventricular tachycardia, only nonsustained (usually polymorphic) runs. Their cumulative beat count and duration paralleled the increased fibrosis between CVB-EEX and CVB-SED, but the difference was not significant (P = 0.084 for each). Interestingly, in mice that were subjected to pretraining only without continuation of exercise during myocarditis, no differences between pretrained and sedentary mice were observed at sacrifice (i.e. 6 weeks after inoculation and training cessation) with regard to myocardial inflammation, fibrosis, and ventricular arrhythmogenicity. In conclusion, endurance exercise during viral myocarditis modulates the inflammatory process with more pro-inflammatory cells and enhances perivascular and interstitial fibrosis development. The impact on ventricular arrhythmogenesis requires further exploration.

Are Endomyocardial Ventricular Biopsies Useful for Assessing Myocardial Fibrosis?

Myocardial fibrosis is an important factor in the progression of cardiovascular diseases. However, there is still no universal lifetime method of myocardial fibrosis assessment that has a high prognostic significance. The aim of the study was to determine the significance of ventricular endomyocardial biopsies for the assessment of myocardial fibrosis and to identify the severity of myocardial fibrosis in different cardiovascular diseases. Material and Methods: Endomyocardial biopsies (EMBs) of 20 patients with chronic lymphocytic myocarditis (CM), endomyocardial fragments obtained during septal reduction of 21 patients with hypertrophic cardiomyopathy (HCM), and 36 patients with a long history of hypertensive and ischemic heart disease (HHD + IHD) were included in the study. The control group was formed from EMBs taken on 12-14 days after heart transplantation (n = 28). Also, for one patient without clinical and morphological data for cardiovascular pathology, postmortem myocardial fragments were taken from typical EMB and septal reduction sites. The relative area of fibrosis was calculated as the ratio of the total area of collagen fibers to the area of the whole biopsy. Endocardium and subendocardial fibrosis were not included in the total biopsy area. Results: The relative fibrosis area in the EMBs in the CM patient group was 5.6 [3.3; 12.6]%, 11.1 [6.6; 15.9]% in the HHD + IHD patient group, 13.4 [8.8; 16.7]% in the HCM patient group, and 2.7 [1.5; 4.6]% in the control group. When comparing the fibrosis area of the CM patients in repeat EMBs, it was found that the fibrosis area in the first EMBs was 7.6 [4.8; 12.0]%, and in repeat EMBs, it was 5.3 [3.2; 7.6]%. No statistically significant differences were found between the primary and repeat EMBs (p = 0.15). In ROC analysis, the area of fibrosis in the myocardium of 1.1% (or lower than one) was found to be highly specific for the control group of patients compared to the study patients. Conclusions: EMB in the assessment of myocardial fibrosis has a questionable role because of the heterogeneity of fibrotic changes in the myocardium.

Early Effects of Modern Radiotherapy for Lung Cancer on Endothelial Damage and Myocardial Fibrosis: A Prospective Single-Center Study.

Radiotherapy (RT) may have a cardiotoxic effect on the heart and cardiovascular system. Postulated mechanisms mediating these complications include vascular endothelium damage and myocardial fibrosis. The aim of our study was to assess endothelial damage and myocardial fibrosis in the early period after RT on the basis of cardiac biomarkers and in relation to the radiation dose applied to individual heart structures in patients treated for non-small-cell lung cancer. This single-center prospective study included consecutive patients with lung cancer (LC) who were referred for treatment with radiochemotherapy (study group) or chemotherapy (control group). The study protocol included performing an echocardiographic examination, a standard ECG examination, and collecting blood samples for laboratory tests before starting treatment for lung cancer in the first week after completing RT (after four cycles of chemotherapy in the control group) and after 12 weeks from the end of treatment. The study included 23 patients in the study group and 20 patients in the control group. Compared to the baseline values, there was a significant increase in total cholesterol concentration in the study group immediately after the end of RT, which persisted for three months after the end of therapy. After taking into account the use of statins in the analysis, it was found that an increase in total cholesterol concentration after oncological treatment was observed only among patients who did not use statins. Taking into account the assessment of myocardial fibrosis markers, there were no significant changes in the concentration of matrix metallopeptidase 9 (MMP-9) and tissue inhibitors of metalloproteinases 1 (TIMP-1) in the study group. In patients treated with radiochemotherapy, there was a significant increase in the concentration of intercellular adhesion molecule 1 (ICAM-1) immediately after RT, when compared to the baseline. After taking into account the use of statins, an increase in ICAM-1 concentration immediately after RT was observed only in patients who did not use statins. There was also a significant correlation between the radiation dose received by the left anterior descending coronary artery (LAD) and left circumferential coronary artery, and vascular cell adhesion protein 1 (VCAM-1) concentration measured at three months after the end of RT. Immediately after completion of radiotherapy, a significant increase in the level of ICAM-1 is observed indicating endothelial damage. The radiation dose to coronary arteries should be minimized, as it correlates with the concentration of VCAM-1. The use of statins may prevent the increase in total cholesterol and ICAM-1 concentration after irradiation for lung cancer; however, further studies designed for this specific purpose are necessary to confirm the effectiveness of statins in this area.

Plasma SMOC2 Predicts Prognosis in Patients with Heart Failure: A Prospective Cohort.

Background: Heart failure (HF) is a chronic disease with a poor prognosis, making it extremely important to assess the prognosis of patients with HF for accurate treatment. Secreted modular calcium-binding protein 2 (SMOC2) is a cysteine-rich acidic secreted protein that plays a pathophysiological role in many diseases, including regulation of vascular growth factor activity. It has previously been found that SMOC2 plays an essential role in cardiac fibrosis in our previous preclinical study, but whether it can be used as a clinical marker in heart failure patients remains unclear. The purpose of this research was to evaluate the correlation between plasma levels of SMOC2 and the prognosis for individuals with HF. Methods: HF patients diagnosed with ischemic cardiomyopathy were enrolled from January to December 2021. Baseline plasma levels of SMOC2 were measured after demographic and clinical features were collected. Linear and nonlinear multivariate Cox regression models were used to determine the association between plasma SMOC2 and patient outcomes during follow-up. All analysis was performed using SPSS, EmpowerStats, and R software. Results: The study included 188 patients, and the average follow-up time was 489.5±88.3 days. The plasma SMOC2 concentrations were positively correlated with N-terminal pro-B-type Natriuretic Peptide (NT-proBNP), left ventricular end-diastolic diameter (LVEDd), and length of hospital stay and were negatively correlated with left ventricular ejection fraction (LVEF) at baseline. A total of 53 patients (28.2%) were rehospitalized due to cardiac deterioration, 14 (7.4%) died, and 37 (19.7%) developed malignant arrhythmias. A fully adjusted multivariate COX regression model showed that SMOC2 is associated with readmission (HR = 1.02, 95% CI:1.012-1.655). A significant increase in rehospitalization risk was observed in group Q2 (HR =1.064, 95% CI: 1.037, 3.662, p=0.005) and group Q3 (HR =1.085, 95% CI:1.086, 3.792, p=0.009) in comparison with group Q1. The p for trend also shows a linear correlation across the three models (P < 0.001). SMOC2 was associated with the severity of HF in patients, but not with all-cause deaths and arrhythmias during follow-up. Conclusion: Plasma SMOC2 is associated with the severity of HF and readmission rate, and is a good predictor of the risk of readmission in patients.

PD-1 Inhibitor Aggravate Irradiation-Induced Myocardial Fibrosis by Regulating TGF-ß1/Smads Signaling Pathway via GSDMD-Mediated Pyroptosis.

Cancer therapy has entered a new era with the use of programmed cell death protein 1 (PD-1) immune checkpoint inhibitors. When combined with thoracic radiotherapy, it demonstrates synergistic anti-tumor effects and potentially worsens radiation-induced myocardial fibrosis (RIMF). RIMF is the final stage of radiation-induced heart disease (RIHD) and a potentially fatal clinical complication of chest radiotherapy. It is characterized by decreased ventricular elasticity and distensibility, which can result in decreased ejection fraction, heart failure, and even sudden cardiac death. Pyroptosis, a type of programmed cell death, is mediated by members of the gasdermin (GSDM) family and has been associated with numerous cardiac disorders. The effect of pyroptosis on myocardial fibrosis caused by a combination of radiotherapy and PD-1 inhibitors remains uncertain. In this study, a 6MV X-ray of 20 Gy for local heart irradiation was used in the RIHD mouse model. We noticed that PD-1 inhibitors aggravated radiation-induced cardiac dysfunction and RIMF, concurrently enhancing the presence of CD8+ T lymphocytes in the cardiac tissue. Additionally, our findings indicated that the combination of PD-1 inhibitor and thoracic radiation can stimulate caspase-1 to cleave GSDMD, thereby regulating pyroptosis and liberating interleukin-8 (IL-18). In the myocardium of mice, the manifestation of pyroptosis mediated by GSDMD is accompanied by the buildup of proteins associated with fibrosis, such as collagen I, transforming growth factor ß1 (TGF-ß1), interleukin-6 (IL-6), vascular endothelial growth factor (VEGF), and tumor necrosis factor α (TNF-α). Moreover, it was discovered that TFG-ß1 induced the phosphorylation of Smad2/Smad3 when the cardiac underwent PD-1 inhibitor in conjunction with thoracic irradiation (IR). The findings of this research indicate that PD-1 inhibitor worsen RIMF in mice by triggering GSDMD-induced pyroptosis and influencing the TGF-ß1/Smads pathway. While using the caspase-1 inhibitor Z-YVAD-FMK, RIMF can be alleviated. Blocking GSDMD may be a viable strategy for managing myocardial fibrosis caused by the combination of PD-1 inhibitors and radiotherapy.

Alterations of Myocardial Mitochondrial Morphology and Function in a Canine Model of Premature Ventricular Contractions-Induced Cardiomyopathy.

AIMS: Changes in myocardial mitochondrial morphology and function in premature ventricular contractions (PVCs)-induced cardiomyopathy (PVCCM) remain poorly studied. Here, we investigated the effects of PVCs with different coupling intervals (CIs) on myocardial mitochondrial remodelling in a canine model of PVCCM. METHODS AND RESULTS: Twenty-one beagles underwent pacemaker implantation and were randomised into the sham (n = 7), short-coupled PVCs (SCP, n = 7), and long-coupled PVCs (LCP, n = 7) groups. Right ventricular (RV) apical bigeminy was produced for 12-week to induce PVCCM in the SCP (CI, 250 ms) and LCP (CI, 350 ms) groups. Echocardiography was performed at baseline and biweekly thereafter to evaluate cardiac function. Masson's trichrome staining measured ventricular interstitial fibrosis. The ultrastructural morphology of the myocardial mitochondria was analysed using transmission electron microscopy. Mitochondrial Ca2+ concentration, reactive oxygen species (ROS) levels, adenosine triphosphate (ATP) content, membrane potential, and electron transport chain (ETC) complex activity were measured to assess myocardial mitochondrial function. Twelve-week-PVCs led to left ventricular (LV) enlargement with systolic dysfunction, disrupted mitochondrial morphology, increased mitochondrial Ca2+ concentration and ROS levels, decreased mitochondrial ATP content and membrane potential, and impaired ETC complex activity in both the SCP and LCP groups (all p < 0.01 vs the sham group). Ventricular fibrosis was observed only in canines with LCP. Worse cardiac function and more pronounced abnormalities in mitochondrial morphology and function were observed in the LCP group than to the SCP group (all p < 0.05). CONCLUSION: We demonstrated myocardial mitochondrial abnormalities in dogs with PVCCM, characterised by abnormal mitochondrial morphology, mitochondrial Ca2+ overload, oxidative stress, and impaired mitochondrial energy metabolism. Compared to SCP, long-term LCP exposure resulted in more severe mitochondrial remodelling and cardiac dysfunction in dogs.

Resistance exercise upregulates Irisin expression and suppresses myocardial fibrosis following myocardial infarction via activating AMPK-Sirt1 and inactivating TGFß1-Smad2/3.

AIM: To reveal the contribution of Irisin in the beneficial effects of resistance exercise on myocardial fibrosis (MF) and cardiac function in the mice with myocardial infarction (MI). METHODS: The MI model was built by ligating the left anterior descending coronary artery in Fndc5 knockout mice (Fndc5-/-). Resistance exercise was started one week after surgery and continued for four weeks. In addition, H2O2, AICAR, recombinant human Irisin protein (rhIRISIN), and Sirt1 shRNA lentivirus (LV-Sirt1 shRNA) were used to intervene primary isolated cardiac fibroblasts (CFs). MF was observed through Masson staining, and apoptosis was assessed using TUNEL staining. MDA and T-SOD contents were detected by biochemical kits. The expression of proteins and genes was detected by Western blotting and RT-qPCR. RESULTS: Resistance exercise increased Fndc5 mRNA level, inhibited the activation of TGFß1-TGFßR2-Smad2/3 pathway, activated AMPK-Sirt1 pathway, reduced the levels of oxidative stress, apoptosis, and MF in the infarcted heart, and promoted cardiac function. However, Fndc5 knockout attenuated the protective effects of resistance exercise on the MI heart. Results of the in vitro experiments showed that AICAR and rhIRISIN intervention activated the AMPK-Sirt1 pathway and inactivated the TGFß1-Smad2/3 pathway, and promoted apoptosis in H2O2-treated CFs. Notably, these effects of rhIRISIN intervention, except for the TGFßR2 expression, were attenuated by LV-Sirt1 shRNA. CONCLUSION: Resistance exercise upregulates Fndc5 expression, activates AMPK-Sirt1 pathway, inhibits the activation of TGFß1-Smad2/3 pathway, attenuates MF, and promotes cardiac function after MI.

Integrative transcriptomics and proteomics analysis reveal the protection of Astragaloside IV against myocardial fibrosis by regulating senescence.

Myocardial fibrosis (MF) is a pivotal pathological process implicated in various cardiovascular diseases, particularly heart failure. Astragaloside IV (AS-IV), a natural compound derived from Astragalus membranaceus, possesses potent cardioprotective properties. However, the precise molecular mechanisms underlying its anti-MF effects, particularly in relation to senescence, remain elusive. Thus, this study aimed to investigate the therapeutic potential and underlying molecular mechanisms of AS-IV in treating ISO-induced MF in mice, employing transcriptomics, proteomics, in vitro, and in vivo experiments. We assessed the positive effects of AS-IV on ISO-induced MF using HE staining, Masson staining, ELISA, immunohistochemical staining, transthoracic echocardiography, transmission electron microscopy, and DHE fluorescence staining. Additionally, we elucidated the regulatory role of AS-IV in MF through comprehensive transcriptomics and proteomics analyses, complemented by Western blotting and RT-qPCR validation of pertinent molecular pathways. Our findings demonstrated that AS-IV treatment markedly attenuated ISO-induced myocardial injury and oxidative stress, concomitantly inhibiting the release of SASPs. Furthermore, integrated transcriptomics and proteomics analyses revealed that the anti-MF mechanism of AS-IV was associated with regulating cellular senescence and the p53 signaling pathway. These results highlight AS-IV exerts its anti-MF effects not only by inhibiting oxidative stress but also by modulating senescence through the p53 signaling pathway.

Elucidating the mechanism of action of Radix Angelica sinensis (Oliv.) Diels and Radix Astragalus mongholicus Bunge ultrafiltration extract on radiation-induced myocardial fibrosis based on network pharmacology and experimental research.

Myocardial fibrosis can induce cardiac dysfunction and remodeling. Great attention has been paid to traditional chinese medicine (TCM) 's effectiveness in treating MF. Radix Angelica sinensis (Oliv.) Diels and Radix Astragalus mongholicus Bunge ultrafiltration extract (RAS-RA), which is a key TCM compound preparation, have high efficacy in regulating inflammation. However, studies on its therapeutic effect on radiation-induced myocardial fibrosis (RIMF) are rare. In this study, RAS-RA had therapeutic efficacy in RIMF and elucidated its mechanism of action. First, we formulated the prediction network that described the relation of RAS-RA with RIMF according to data obtained in different databases. Then, we conducted functional enrichment to investigate the functions and pathways associated with potential RIMF targets for RAS-RA. In vivo experiments were also performed to verify these functions and pathways. Second, small animal ultrasound examinations, H&E staining, Masson staining, transmission electron microscopy, Enzyme-linked immunosorbent assay (ELISA), Western-blotting, Immunohistochemical method and biochemical assays were conducted to investigate the possible key anti-RIMF pathway in RAS-RA. In total, 440 targets were detected in those 21 effective components of RAS-RA; meanwhile, 1,646 RIMF-related disease targets were also discovered. After that, PPI network analysis was conducted to identify 20 key targets based on 215 overlap gene targets. As indicated by the gene ontology (GO) and kyoto encyclopedia of genes and genomes (KEGG) analysis results, inflammation and PI3K/AKT/mTOR pathways might have important effects on the therapeutic effects on RIMF. Molecular docking analysis revealed high binding of effective components to targets (affinity < -6 kcal/mol). Based on experimental verification results, RAS-RA greatly mitigated myocardial fibrosis while recovering the cardiac activity of rats caused by X-rays. According to relevant protein expression profiles, the PI3K/AKT/mTOR pathway was important for anti-fibrosis effect of RAS-RA. Experimental studies showed that RAS-RA improved cardiac function, decreased pathological damage and collagen fiber deposition in cardiac tissues, and improved the mitochondrial structure of the heart of rats. RAS-RA also downregulated TNF-α, IL-6, and IL-1ß levels. Additionally, RAS-RA improved the liver and kidney functions and pathological injury of rat kidney and liver tissues, enhanced liver and kidney functions, and protected the liver and kidneys. RAS-RA also increased PI3K, AKT and mTOR protein levels within cardiac tissues and downregulated α-SMA, Collagen I, and Collagen III. The findings of this study suggested that RAS-RA decreased RIMF by suppressing collagen deposition and inflammatory response by inhibiting the PI3K/AKT/mTOR pathway. Thus, RAS-RA was the potential therapeutic agent used to alleviate RIMF.