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Background: Influenza B virus induced myocarditis is a rare complication with potentially wide variations in severity and clinical presentation, and the pathogenesis is unclear. Case presentation: We describe a rare case of a 7-year-old boy who developed fulminant myocarditis (FM) due to influenza B virus infection. Treatment measures included mechanical ventilation, vasoactive agents, Extracorporeal membrane oxygenation (ECMO), Continuous Renal Replacement Therapy (CRRT), anti-inflammatory, antiviral, anti-infection, and enteral nutrition support. After 10 days of treatment, the patient succumbed to multiorgan failure. Conclusions: After a systematic review of the literature, we found that this disease predominantly affects females, with pediatric cases exceedingly rare. Fulminant myocarditis (FM) progresses rapidly, poses significant treatment challenges sporadic, and carries a poor prognosis. Interestingly, literature reports suggest that anti-thymocyte globulin therapy may have a positive impact in treating FM, potentially offering new insights into its pathogenesis and clinical management. [ABSTRACT FROM AUTHOR]

Objective: To study the role and preliminary molecular mechanism of TRIM24 regulating macrophage polarization in viral myocarditis （VM）. Methods: VM mouse model was established by Coxsackie virus B3（ CVB3）, and expression of TRIM24 in myocardial tissue was detected. Cardiac inflammation level and polarization phenotype of cardiac infiltrating macrophages in a murine model of cardiac TRIM24 inhibition were detected in vivo. A polarization model of mouse bone marrow-derived macrophages（ BMDMs） in vitro was established to observe the role of TRIM24 inhibition in polarizing BMDMs to M1 and M2, as well as its effects on phagocytosis and bactericidal function of BMDMs. Effects of TRIM24 inhibition on total STAT6 protein level and phosphorylation were investigated. Results: TRIM24 was significantly highly expressed in myocardial tissue of VM mice （P<0.001）. Inhibition of TRIM24 expression in myocardium had an attenuating effect on VM and promoted polarization of cardiac infiltrating macrophages to M2. TRIM24 was significantly down-regulated in vitro during the polarization of BMDMs toward M2 （P<0.01）. Inhibition of TRIM24 expression significantly promoted macrophage polarization toward M2 type and inhibited polarization toward M1 type, accompanied by a significant increase in STAT6 phosphorylation levels （P<0.01）. Conclusion: TRIM24 regulates macrophage M2 polarization via activation of STAT6 signaling pathway to attenuate VM. [ABSTRACT FROM AUTHOR]

Background: This study aims to evaluate the role of parvovirus B19 (B19V) in the pathogenesis of myocarditis in a paediatric population, including post-mortem samples from two children. Methods: From 2004 to 2023, endomyocardial biopsies (EMBs) from children under 16 years of age were analyzed using histology, immunohistochemistry, and molecular pathology. A total of 306 children with acute and 1060 children with chronic lymphocytic myocarditis were identified. Results: B19V infection was more frequent in acute myocarditis than in chronic myocarditis (43% vs. 14%), with higher viral loads in acute cases regardless of age. The most prominent cardiac CD3+ T cell infiltration was noted in children < 2 years, correlating with high cardiac B19V loads. In two male infants who died from B19V infection, B19V DNA was localized in the endothelial cells of multiple organs using in situ hybridization. Virus replication was found in the endothelial cells of small cardiac arterioles and venules but not in capillaries. B19V DNA/mRNA was also detected in immune cells, especially in the spleen and lymph nodes, revealing virus replication in B lymphocytes. Conclusions: B19V can induce severe lymphocytic myocarditis, especially in young children. The simultaneous histopathological and molecular assessment of EMBs is important for early diagnosis of viral myocarditis, preventing severe disease, and ensuring appropriate therapy. [ABSTRACT FROM AUTHOR]

Viral myocarditis (VMC) is the major reason for sudden cardiac death among both children and young adults. Of these, coxsackievirus B3 (CVB3) is the most common causative agent of myocarditis. Recently, the role of signaling pathways in the pathogenesis of VMC has been evaluated in several studies, which has provided a new perspective on identifying potential therapeutic targets for this hitherto incurable disease. In the present study, in vivo and in vitro experiments showed that CVB3 infection leads to increased Bim expression and triggers apoptosis. In addition, by knocking down Bim using RNAi, we further confirmed the biological function of Bim in apoptosis induced by CVB3 infection. We additionally found that Bim and forkhead box O1 class (FOXO1) inhibition significantly increased the viability of CVB3-infected cells while blocking viral replication and viral release. Moreover, CVB3-induced Bim expression was directly dependent on FOXO1 acetylation, which is catalyzed by the co-regulation of CBP and SirTs. Furthermore, the acetylation of FOXO1 was an important step in Bim activation and apoptosis induced by CVB3 infection. The findings of this study suggest that CVB3 infection induces apoptosis through the FOXO1 acetylation-Bim pathway, thus providing new insights for developing potential therapeutic targets for enteroviral myocarditis. [ABSTRACT FROM AUTHOR]

Abstract Background Influenza B virus induced myocarditis is a rare complication with potentially wide variations in severity and clinical presentation, and the pathogenesis is unclear. Case presentation We describe a rare case of a 7-year-old boy who developed fulminant myocarditis (FM) due to influenza B virus infection. Treatment measures included mechanical ventilation, vasoactive agents, Extracorporeal membrane oxygenation (ECMO), Continuous Renal Replacement Therapy (CRRT), anti-inflammatory, antiviral, anti-infection, and enteral nutrition support. After 10 days of treatment, the patient succumbed to multiorgan failure. Conclusions After a systematic review of the literature, we found that this disease predominantly affects females, with pediatric cases exceedingly rare. Fulminant myocarditis (FM) progresses rapidly, poses significant treatment challenges sporadic, and carries a poor prognosis. Interestingly, literature reports suggest that anti-thymocyte globulin therapy may have a positive impact in treating FM, potentially offering new insights into its pathogenesis and clinical management.

Abstract 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.

Abstract Background Viral myocarditis (VMC) is a disease resulting from viral infection, which manifests as inflammation of myocardial cells. Until now, the treatment of VMC is still a great challenge for clinicians. Increasing studies indicate the participation of miR-29b-3p in various diseases. According to the transcriptome sequencing analysis, miR-29b-3p was markedly upregulated in the viral myocarditis model. The purpose of this study was to investigate the role of miR-29b-3p in the progression of VMC. Methods We used CVB3 to induce primary cardiomyocytes and mice to establish a model of viral myocarditis. The purity of primary cardiomyocytes was identified by immunofluorescence. The cardiac function of mice was detected by Vevo770 imaging system. The area of inflammatory infiltration in heart tissue was shown by hematoxylin and eosin (H&E) staining. The expression of miR-29b-3p and DNMT3A was detected by quantitative real time polymerase chain reaction (qRT–PCR). The expression of a series of pyroptosis-related proteins was detected by western blot. The role of miR-29b-3p/DNMT3A in CVB3-induced pyroptosis of cardiomyocytes was studied in this research. Results Our data showed that the expression of miR-29b-3p was upregulated in CVB3-induced cardiomyocytes and heart tissues in mice. To explore the function of miR-29b-3p in CVB3-induced VMC, we conducted in vivo experiments by knocking down the expression of miR-29b-3p using antagomir. We then assessed the effects on mice body weight, histopathology changes, myocardial function, and cell pyroptosis in heart tissues. Additionally, we performed gain/loss-of-function experiments in vitro to measure the levels of pyroptosis in primary cardiomyocytes. Through bioinformatic analysis, we identified DNA methyltransferases 3A (DNMT3A) as a potential target gene of miR-29b-3p. Furthermore, we found that the expression of DNMT3A can be modulated by miR-29b-3p during CVB3 infection. Conclusions Our results demonstrate a correlation between the expression of DNMT3A and CVB3-induced pyroptosis in cardiomyocytes. These findings unveil a previously unidentified mechanism by which CVB3 induces cardiac injury through the regulation of miR-29b-3p/DNMT3A-mediated pyroptosis.

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. [ABSTRACT FROM AUTHOR]

The purpose of this paper was to unravel the clinical effect analysis of different doses of creatine phosphate sodium (CPS) combined with immunoglobulin in the treatment of pediatric viral myocarditis (VMC). One hundred and twenty children with VMC were recruited and randomized into three groups (40 patients each). Group I received 1.0 g of CPS dissolved in 100 mL of 5% glucose injection intravenously 1 time/day; group II received 1.25 g of CPS dissolved in 125 mL of 5% glucose injection intravenously 1 time/day; group III received 1.5 g of CPS dissolved in 150 mL of 5% glucose injection intravenously 1 time/day; then all three groups were treated with combined use of immunoglobulin (300–400 mg/day) intravenously once a day; and all three groups were treated for 14 days. The clinical efficacy, cardiac function, serum inflammatory factor levels, immune function, and the occurrence of drug toxicity and adverse effects of the children in the three groups were compared after 14 days of treatment. All three groups achieved better therapeutic effects after treatment, in which the effective rate of the Group II and Group III was notably higher versus the Group I. Lower levels of cTnI, CK-MB, LDH, AST, IL-18, IL-6, IFN-γ, and LVEDD and higher CD3+, CD4+, and CD4+/CD8+, FS, and LVEF values were noted in the Group II and Group III versus the Group I, and the results were more pronounced in the high-dose group. The liver and kidney functions of the children in the three groups before and after treatment did not show any significant changes and the incidence of adverse reactions during the treatment period was low in all three groups. Children with VMC can be treated with high-dose CPS in combination with immunoglobulin, which can improve their cardiac function and immune function and reduce the inflammatory response with good overall therapeutic efficacy and fewer adverse effects. [ABSTRACT FROM AUTHOR]

Calcium/calmodulin-dependent protein kinase II (CaMKII) has been demonstrated to be aberrantly activated in viral myocarditis (VMC), but the role of its subtype CaMKIIδ in VMC remains unclear. VMC mice and cardiomyocytes models were induced by Coxsackievirus B3 (CVB3) treatment. Mice that underwent sham surgery and saline-treated cardiomyocytes served as controls. Body weight, survival, left ventricular ejection fraction (LVEF), and fractional shortening (LVFS) were measured, and HE staining was performed to evaluate heart function in VMC mice model and sham control. Inflammation factors in serum or cell supernatant were detected by ELISA. Expressions of CaMKIIδ, Toll/interleukin-1 receptor domain containing adaptor protein (TIRAP), insulin-like growth factor 2 mRNA binding protein 2 (IGF2BP2), nuclear factor NF-kappaB (NF-κB) signals, and inflammation factors were examined by quantitative real time polymerase chain reaction (qRT-PCR) or western blot. CCK-8, EdU, and flow cytometry were used to evaluate cell behaviors. Co-immunoprecipitation (Co-IP), RNA immunoprecipitation (RIP), and RNA pull-down were utilized to validate molecule interaction. Methylated RNA immunoprecipitation (MeRIP) was performed to measure N6-methyladenosine (m6A) level of specific molecule. CaMKIIδ was upregulated in VMC mice and CVB3-treated primary cardiomyocytes, of which knockdown improved cell viability, proliferation, and suppressed cell apoptosis in vitro, thereby alleviating myocarditis in vivo. The stability of CaMKIIδ was attributed to the presence of IGF2BP2 through m6A modification. Loss of CaMKIIδ repressed NF-κB pathway via negatively and directly regulating TIRAP to be involved in inflammatory damage. CaMKIIδ, stabilized by m6A reader IGF2BP2, modulated NF-κB pathway via interacting with TIRAP to alter cell viability, proliferation, and apoptosis, thereby affecting VMC outcome. [ABSTRACT FROM AUTHOR]

Background: Viral myocarditis (VMC) is a disease resulting from viral infection, which manifests as inflammation of myocardial cells. Until now, the treatment of VMC is still a great challenge for clinicians. Increasing studies indicate the participation of miR-29b-3p in various diseases. According to the transcriptome sequencing analysis, miR-29b-3p was markedly upregulated in the viral myocarditis model. The purpose of this study was to investigate the role of miR-29b-3p in the progression of VMC. Methods: We used CVB3 to induce primary cardiomyocytes and mice to establish a model of viral myocarditis. The purity of primary cardiomyocytes was identified by immunofluorescence. The cardiac function of mice was detected by Vevo770 imaging system. The area of inflammatory infiltration in heart tissue was shown by hematoxylin and eosin (H&E) staining. The expression of miR-29b-3p and DNMT3A was detected by quantitative real time polymerase chain reaction (qRT–PCR). The expression of a series of pyroptosis-related proteins was detected by western blot. The role of miR-29b-3p/DNMT3A in CVB3-induced pyroptosis of cardiomyocytes was studied in this research. Results: Our data showed that the expression of miR-29b-3p was upregulated in CVB3-induced cardiomyocytes and heart tissues in mice. To explore the function of miR-29b-3p in CVB3-induced VMC, we conducted in vivo experiments by knocking down the expression of miR-29b-3p using antagomir. We then assessed the effects on mice body weight, histopathology changes, myocardial function, and cell pyroptosis in heart tissues. Additionally, we performed gain/loss-of-function experiments in vitro to measure the levels of pyroptosis in primary cardiomyocytes. Through bioinformatic analysis, we identified DNA methyltransferases 3A (DNMT3A) as a potential target gene of miR-29b-3p. Furthermore, we found that the expression of DNMT3A can be modulated by miR-29b-3p during CVB3 infection. Conclusions: Our results demonstrate a correlation between the expression of DNMT3A and CVB3-induced pyroptosis in cardiomyocytes. These findings unveil a previously unidentified mechanism by which CVB3 induces cardiac injury through the regulation of miR-29b-3p/DNMT3A-mediated pyroptosis. [ABSTRACT FROM AUTHOR]

Objective: To analyze the serum levels of exosome miRNA-135-5p in children with viral myocarditis, and to evaluate its clinical value to the myocardial injury degree and prognosis by inhibiting AKT/mTOR signal pathway. Methods: The 50 children with viral myocarditis in our hospital were collected and divided into the two groups according to the degree of viral myocarditis, which were severe group (15 cases) and mild group (35 cases). The 30 healthy examinees were collected to control group. The serum levels of exosome miRNA-135-5p, AKT mRNA and mTOR mRNA were detected by reverse transcription-polymerase chain reaction (RT-PCR) and compared among 3 groups. The correlations of exosome miRNA-135-5p to serum AKT mRNA and mTOR mRNA were confirmed by Pearson linear correlation analysis. The risk factors of illness degree of children with viral myocarditis to the clinical indexes were confirmed by multivariate Logistic analysis. Follow-up 12 months, the diagnostic value of exosome miRNA-135-5p to the 12 months follow-up prognosis of the children with viral myocarditis were analyzed by receiver operating characteristic curves (ROC). Results: Compared to control group, the serum levels of exosome miRNA-135-5p in severe group and mild group were higher, and severe group higher than mild group(P<0.05). The serum levels of AKT, mTOR mRNA in severe group and mild group were lower than control group, and severe group lower than mild group (P<0.05). The negative correlations of exosome miRNA-135-5p to serum AKT mRNA and mTOR mRNA were confirmed by Pearson linear correlation analysis (P<0.05). Multivariate Logistic analysis showed that the serum levels of exosome miRNA-135-5p were independent risk factors to the 12 months follow-up prognosis of children with viral myocarditis, but the levels of AKT mRNA and mTOR mRNA were the protective factors (P<0.05). When the cut-off point of exosome miRNA-135-5p was 3.32, the AUC was 0.822 and the sensitivity was 86.3 % and specificity was 80.6 %. Conclusions: The serum levels of exosome miRNA-135-5p is the risk factor to the myocardial injury degree in children with viral myocarditis by inhibiting AKT/mTOR signal pathway, and can perfect assess the 6 months follow-up prognosis. [ABSTRACT FROM AUTHOR]

Background: Severe myocarditis is often accompanied by cardiac fibrosis, but the underlying mechanism has not been fully elucidated. CXCL4 is a chemokine that has been reported to have pro‐inflammatory and profibrotic functions. The exact role of CXCL4 in cardiac fibrosis remains unclear. Methods: Viral myocarditis (VMC) models were induced by intraperitoneal injection of Coxsackie B Type 3 (CVB3). In vivo, CVB3 (100 TCID50) and CVB3‐AMG487 (CVB3: 100 TCID50; AMG487: 5 mg/kg) combination were administered in the VMC and VMC+AMG487 groups, respectively. Hematoxylin and eosin staining, severity score, Masson staining, and immunofluorescence staining were performed to measure myocardial morphology in VMC. Enzyme‐linked immunosorbent assay (ELISA) and quantitative reverse transcription polymerase chain reaction (qRT‐PCR) were performed to quantify inflammatory factors (IL‐1β, IL‐6, TNF‐α, and CXCL4). Aspartate aminotransferase (AST), lactate dehydrogenase (LDH), and creatine kinase‐myocardial band (CK‐MB) levels were analyzed by commercial kits. CXCL4, CXCR3B, α‐SMA, TGF‐β1, Collagen I, and Collagen III were determined by Western blot and immunofluorescence staining. Results: In vivo, CVB3‐AMG487 reduced cardiac injury, α‐SMA, Collagen I and Collagen III levels, and collagen deposition in VMC+AMG487 group. Additionally, compared with VMC group, VMC+AMG group decreased the levels of inflammatory factors (IL‐1β, IL‐6, and TNF‐α). In vitro, CXCL4/CXCR3B axis activation TGF‐β1/Smad2/3 pathway promote mice cardiac fibroblasts differentiation. Conclusion: CXCL4 acts as a profibrotic factor in TGF‐β1/Smad2/3 pathway‐induced cardiac fibroblast activation and ECM synthesis, and eventually progresses to cardiac fibrosis. Therefore, our findings revealed the role of CXCL4 in VMC and unveiled its underlying mechanism. CXCL4 appears to be a potential target for the treatment of VMC. [ABSTRACT FROM AUTHOR]

Myocarditis is a serious condition that carries with it a high rate of morbidity and mortality. This review highlights the pearls and pitfalls of myocarditis, including presentation, diagnosis, and management in the emergency department (ED) based on current evidence. Myocarditis is an inflammatory syndrome of myocardium, most often resulting from a viral infection, that can cause life-threatening cardiovascular collapse. It has a highly variable presentation and no widely available specific diagnostic test, making it a challenging diagnosis. Emergency clinicians should obtain an electrocardiogram and perform bedside ultrasound to assess cardiac function. Treatment in the ED is largely supportive, focusing on resuscitation, cardiovascular support, cardiology specialist consultation, and appropriate disposition. An understanding of myocarditis can assist emergency clinicians in diagnosing and managing this potentially deadly disease. [ABSTRACT FROM AUTHOR]

To explore the association and impact between viral myocarditis and mortality in patients with severe fever with thrombocytopenia syndrome. A dynamic analysis was conducted between fatal group and nonfatal group regarding the daily epidemiology data, clinical symptoms, and electrocardiogram (ECG), echocardiogram, and laboratory findings. Outcomes of patients with and without viral myocarditis were compared. The association between viral myocarditis and mortality was analyzed. Among 183 severe fever with thrombocytopenia syndrome patients, 32 were in the fatal group and 151 in the nonfatal group; there were 26 (81.25%) with viral myocarditis in the fatal group, 66 (43.70%) with viral myocarditis in the nonfatal group (p < 0.001), 79.35% of patients had abnormal ECG results. The abnormal rate of ECG in the fatal group was 100%, and in the nonfatal group was 74.83%. Univariate analysis found that the number of risk factors gradually increased on Day 7 of the disease course and reached the peak on Day 10. Combined with the dynamic analysis of the disease course, alanine aminotransferase, aspartate aminotransferase, creatine kinase, creatine kinase fraction, lactate dehydrogenase, hydroxybutyrate dehydrogenase, neutrophil count, serum creatinine, Na, Ca, carbon dioxide combining power, amylase, lipase, activated partial thromboplastin time and thrombin time had statistically significant impact on prognosis. The incidence of fever with thrombocytopenia syndrome combined with viral myocarditis is high, especially in the fatal group of patients. Viral myocarditis is closely related to prognosis and is an early risk factor. The time point for changes in myocarditis is Day 7 of the course of the disease. [ABSTRACT FROM AUTHOR]

Abstract Objective This study aimed to investigate the clinical characteristics of severe fever with thrombocytopenia syndrome complicated by viral myocarditis (SFTS-VM) and analyze relevant influencing factors. Methods Retrospective analysis was conducted on clinical data from 79 SFTS-VM patients, categorized into common (SFTS-CVM, n = 40) and severe groups (SFTS-SVM, n = 39). Clinical manifestations, laboratory results, cardiac ultrasonography, and electrocardiogram features were analyzed. Univariate and multivariate analyses identified significant indicators, which were further assessed using ROC curves to predict SFTS-SVM. Results SFTS-SVM group exhibited higher rates of hypotension, shock, abdominal pain, cough with sputum, and consciousness disorders compared to SFTS-CVM group. Laboratory findings showed elevated platelet count, ALT, AST, amylase, lipase, LDH, D-dimer, procalcitonin, TNI, and NT-proBNP in SFTS-SVM. Abnormal electrocardiograms, especially atrial fibrillation, were more prevalent in SFTS-SVM (P 978.5U/L) and NT-proBNP (> 857.5pg/ml)) indicated increased likelihood of SFTS progression into SVM. Conclusion Elevated LDH, NT-proBNP, and consciousness disorders independently correlate with SFTS-SVM. LDH and NT-proBNP can aid in early identification of SFTS-SVM development when above specified thresholds.

Abstract Aims Studies have confirmed that viral myocarditis (VMC) is one of the risk factors for dilated cardiomyopathy (DCM). The molecular mechanisms underlying the progression from VMC to DCM remain unclear and require further investigation. Methods and results The mRNA microarray datasets GSE57338 (DCM) and GSE1145 (VMC) were obtained from the Gene Expression Omnibus database. The candidate key genes were further screened using weighted correlation network analysis (WGCNA), protein–protein interaction and external dataset validation, and the correlation between the candidate key genes and immune cells and the signalling pathways of the candidate key genes were observed by enrichment analysis and immune infiltration analysis. The expression of key genes was validated in the external dataset GSE35182. The crosstalk genes between DCM and VMC were mainly enriched in ‘transcriptional misregulation in cancer’, ‘FoxO signalling pathway’, ‘AGE‐RAGE signalling pathway in diabetic complications’, ‘thyroid hormone signalling pathway’, ‘AMPK signalling pathway’, and other signalling pathways. The immune infiltration analysis indicated that VMC was mainly associated with resting dendritic cells and M0 macrophages, while DCM was mainly associated with monocytes, M0 macrophages, CD8+ T cells, resting CD4 memory T cells, naive CD4+ T cells, and resting mast cells. In DCM‐related dataset GSE57338 and VMC‐related dataset GSE1145, a total of 18 candidate key genes were differentially expressed. BLC6, FOXO1, and UBE2M were identified as the key genes that lead to the progression from VMC to DCM by GSE35182. Conclusions Three key genes (BLC6, FOXO1, and UBE2M) were identified and provided new insights into the diagnosis and treatment of VMC with DCM.

Objective: To explore the mechanism by which icariin alleviates viral myocarditis. Methods: CVB3-induced cardiomyocytes were used as an in vitro model of viral myocarditis to assess the effects of icariin treatment on cell viability, inflammation, and apoptosis. Moreover, the effects of icariin on ferroptosis and TLR4 signaling were assessed. After AC16 cells were transfected with TLR4 overexpression plasmids, the role of TLR4 in mediating the regulatory effect of icariin in viral myocarditis was investigated. Results: Icariin significantly elevated cell viability and reduced inflammatory factors TNF-α, IL-1β, IL-6, and IL-18. Flow cytometry revealed that icariin decreased apoptosis rate, and the protein expression of Bax and cleaved caspase 3 and 9 in CVB3-induced cardiomyocytes. Additionally, it suppressed ferroptosis including lipid peroxidation and ferrous ion, as well as the TLR4 signaling. However, TLR4 overexpression abrogated the modulatory effects of icariin. Conclusions: Icariin mitigates CVB3-induced myocardial injury by inhibiting TLR4-mediated ferroptosis. Further animal study is needed to verify its efficacy.

Objective: This study aimed to investigate the clinical characteristics of severe fever with thrombocytopenia syndrome complicated by viral myocarditis (SFTS-VM) and analyze relevant influencing factors. Methods: Retrospective analysis was conducted on clinical data from 79 SFTS-VM patients, categorized into common (SFTS-CVM, n = 40) and severe groups (SFTS-SVM, n = 39). Clinical manifestations, laboratory results, cardiac ultrasonography, and electrocardiogram features were analyzed. Univariate and multivariate analyses identified significant indicators, which were further assessed using ROC curves to predict SFTS-SVM. Results: SFTS-SVM group exhibited higher rates of hypotension, shock, abdominal pain, cough with sputum, and consciousness disorders compared to SFTS-CVM group. Laboratory findings showed elevated platelet count, ALT, AST, amylase, lipase, LDH, D-dimer, procalcitonin, TNI, and NT-proBNP in SFTS-SVM. Abnormal electrocardiograms, especially atrial fibrillation, were more prevalent in SFTS-SVM (P < 0.05). Multivariate analysis identified elevated LDH upon admission (OR = 1.004, 95% CI: 1-1.008, P = 0.050), elevated NT-proBNP (OR = 1.005, 95% CI: 1.001–1.008, P = 0.007), and consciousness disorders (OR = 112.852, 95% CI: 3.676 ~ 3464.292, P = 0.007) as independent risk factors for SFTS-SVM. LDH and NT-proBNP had AUCs of 0.728 and 0.744, respectively, in predicting SFTS-SVM. Critical values of LDH (> 978.5U/L) and NT-proBNP (> 857.5pg/ml)) indicated increased likelihood of SFTS progression into SVM. Conclusion: Elevated LDH, NT-proBNP, and consciousness disorders independently correlate with SFTS-SVM. LDH and NT-proBNP can aid in early identification of SFTS-SVM development when above specified thresholds. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the effectiveness of sodium creatine phosphate (SCP) in pediatric viral myocarditis, and cellular immune functions. Methods: Clinical data of 83 children with viral myocarditis admitted to Dezhou Traditional Chinese Medicine Hospital, China between May 2019 and June 2021 were collected and randomly assigned to control (n = 41) and study groups (n = 42). Control group (CNG) received conventional treatment for 14 days, including intravenous drip of sodium fructose diphosphate, vitamin C, and ribavirin, with the addition of prednisone if necessary. Study group (SG) received SCP in addition to conventional treatment for 14 days. Clinical efficacy, cardiac function, inflammatory and immune markers, myocardial injury, and adverse effects at the end of treatment were determined. Results: Results indicated a significantly higher total effective rate in study group (95.24 %) compared to control group (78.05 %) (p < 0.05). Study group demonstrated significantly lower heart rates and improved cardiac output, stroke volume, and left ventricular ejection fraction after 14 days of treatment compared to control group (p < 0.05). Furthermore, study group exhibited significant reduction in levels of inflammatory markers (p < 0.05), enhanced cellular immune markers (p < 0.05), and reduced myocardial injury and remodeling markers (p < 0.05). Both groups showed similar incidence of adverse reactions. Conclusion: Sodium creatine phosphate (SCP) is effective in treating pediatric viral myocarditis, enhances cardiac function, restores cellular immune function, reduces inflammation, and minimizes myocardial damage and remodeling. There will be need to evaluate the long-term efficacy and prognosis of SCP in treating pediatric viral myocarditis in the future. [ABSTRACT FROM AUTHOR]

Aims: Studies have confirmed that viral myocarditis (VMC) is one of the risk factors for dilated cardiomyopathy (DCM). The molecular mechanisms underlying the progression from VMC to DCM remain unclear and require further investigation. Methods and results: The mRNA microarray datasets GSE57338 (DCM) and GSE1145 (VMC) were obtained from the Gene Expression Omnibus database. The candidate key genes were further screened using weighted correlation network analysis (WGCNA), protein–protein interaction and external dataset validation, and the correlation between the candidate key genes and immune cells and the signalling pathways of the candidate key genes were observed by enrichment analysis and immune infiltration analysis. The expression of key genes was validated in the external dataset GSE35182. The crosstalk genes between DCM and VMC were mainly enriched in 'transcriptional misregulation in cancer', 'FoxO signalling pathway', 'AGE‐RAGE signalling pathway in diabetic complications', 'thyroid hormone signalling pathway', 'AMPK signalling pathway', and other signalling pathways. The immune infiltration analysis indicated that VMC was mainly associated with resting dendritic cells and M0 macrophages, while DCM was mainly associated with monocytes, M0 macrophages, CD8+ T cells, resting CD4 memory T cells, naive CD4+ T cells, and resting mast cells. In DCM‐related dataset GSE57338 and VMC‐related dataset GSE1145, a total of 18 candidate key genes were differentially expressed. BLC6, FOXO1, and UBE2M were identified as the key genes that lead to the progression from VMC to DCM by GSE35182. Conclusions: Three key genes (BLC6, FOXO1, and UBE2M) were identified and provided new insights into the diagnosis and treatment of VMC with DCM. [ABSTRACT FROM AUTHOR]

Abstract Background Severe myocarditis is often accompanied by cardiac fibrosis, but the underlying mechanism has not been fully elucidated. CXCL4 is a chemokine that has been reported to have pro‐inflammatory and profibrotic functions. The exact role of CXCL4 in cardiac fibrosis remains unclear. Methods Viral myocarditis (VMC) models were induced by intraperitoneal injection of Coxsackie B Type 3 (CVB3). In vivo, CVB3 (100 TCID50) and CVB3‐AMG487 (CVB3: 100 TCID50; AMG487: 5 mg/kg) combination were administered in the VMC and VMC+AMG487 groups, respectively. Hematoxylin and eosin staining, severity score, Masson staining, and immunofluorescence staining were performed to measure myocardial morphology in VMC. Enzyme‐linked immunosorbent assay (ELISA) and quantitative reverse transcription polymerase chain reaction (qRT‐PCR) were performed to quantify inflammatory factors (IL‐1β, IL‐6, TNF‐α, and CXCL4). Aspartate aminotransferase (AST), lactate dehydrogenase (LDH), and creatine kinase‐myocardial band (CK‐MB) levels were analyzed by commercial kits. CXCL4, CXCR3B, α‐SMA, TGF‐β1, Collagen I, and Collagen III were determined by Western blot and immunofluorescence staining. Results In vivo, CVB3‐AMG487 reduced cardiac injury, α‐SMA, Collagen I and Collagen III levels, and collagen deposition in VMC+AMG487 group. Additionally, compared with VMC group, VMC+AMG group decreased the levels of inflammatory factors (IL‐1β, IL‐6, and TNF‐α). In vitro, CXCL4/CXCR3B axis activation TGF‐β1/Smad2/3 pathway promote mice cardiac fibroblasts differentiation. Conclusion CXCL4 acts as a profibrotic factor in TGF‐β1/Smad2/3 pathway‐induced cardiac fibroblast activation and ECM synthesis, and eventually progresses to cardiac fibrosis. Therefore, our findings revealed the role of CXCL4 in VMC and unveiled its underlying mechanism. CXCL4 appears to be a potential target for the treatment of VMC.

Background: This study aims to evaluate the role of parvovirus B19 (B19V) in the pathogenesis of myocarditis in a paediatric population, including post-mortem samples from two children. Methods: From 2004 to 2023, endomyocardial biopsies (EMBs) from children under 16 years of age were analyzed using histology, immunohistochemistry, and molecular pathology. A total of 306 children with acute and 1060 children with chronic lymphocytic myocarditis were identified. Results: B19V infection was more frequent in acute myocarditis than in chronic myocarditis (43% vs. 14%), with higher viral loads in acute cases regardless of age. The most prominent cardiac CD3+ T cell infiltration was noted in children < 2 years, correlating with high cardiac B19V loads. In two male infants who died from B19V infection, B19V DNA was localized in the endothelial cells of multiple organs using in situ hybridization. Virus replication was found in the endothelial cells of small cardiac arterioles and venules but not in capillaries. B19V DNA/mRNA was also detected in immune cells, especially in the spleen and lymph nodes, revealing virus replication in B lymphocytes. Conclusions: B19V can induce severe lymphocytic myocarditis, especially in young children. The simultaneous histopathological and molecular assessment of EMBs is important for early diagnosis of viral myocarditis, preventing severe disease, and ensuring appropriate therapy.

Exploring the immune mechanism of coxsackievirus B3 (CVB3)-induced myocarditis may provide a promising therapeutic strategy. Here, we investigated the regulatory role of macrophage CAPN4 in the phenotypic transformation of macrophages and NOD-like receptor protein 3 (NLRP3) inflammasome activation. We found that CAPN4 was the most upregulated subtype of the calpain family in CVB3-infected bone marrow-derived macrophages (BMDMs) and Raw 264.7 cells after CVB3 infection and was upregulated in cardiac macrophages from CVB3-infected mice. Conditional knockout of CAPN4 (CAPN4flox/flox; LYZ2-Cre, CAPN4-cKO mice) ameliorated inflammation and myocardial injury and improved cardiac function and survival after CVB3 infection. Enrichment analysis revealed that macrophage differentiation and the interleukin signaling pathway were the most predominant biological processes in macrophages after CVB3 infection. We further found that CVB3 infection and the overexpression of CAPN4 promoted macrophage M1 polarization and NLRP3 inflammasome activation, while CAPN4 knockdown reversed these changes. Correspondingly, CAPN4-cKO alleviated CVB3-induced M1 macrophage transformation and NLRP3 expression and moderately increased M2 transformation in vivo. The culture supernatant of CAPN4-overexpressing or CVB3-infected macrophages impaired cardiac fibroblast function and viability. Moreover, macrophage CAPN4 could upregulate C/EBP-homologous protein (chop) expression, which increased proinflammatory cytokine release by activating the phosphorylation of transducer of activator of transcription 1 (STAT1) and 3 (STAT3). Overall, these results suggest that CAPN4 increases M1-type and inhibits M2-type macrophage polarization through the chop-STAT1/STAT3 signaling pathway to mediate CVB3-induced myocardial inflammation and injury. CAPN4 may be a novel target for viral myocarditis treatment. [Display omitted] • Macrophage CAPN4 regulates cell polarization and NLRP3 inflammasome activation after coxsackievirus B3 (CVB3) infection. • Chop expression was altered by the effects of CAPN4 and CVB3 infection. • Chop regulates M1 polarization and NLRP3 inflammasome activation via the STAT1/STAT3 signaling pathway. • Macrophage CAPN4 is a novel therapeutic target for infectious, inflammatory diseases. [ABSTRACT FROM AUTHOR]

Myocarditis can result from various infectious and non‐infectious causes that can lead to dilated cardiomyopathy (DCM) and heart failure. Among the infectious causes, viruses are commonly suspected. But the challenge is our inability to demonstrate infectious viral particles during clinical presentations, partly because by that point, the viruses would have damaged the tissues and be cleared by the immune system. Therefore, viral signatures such as viral nucleic acids and virus‐reactive antibodies may be the only readouts pointing to viruses as potential primary triggers of DCM. Thus, it becomes hard to explain persistent inflammatory infiltrates that might occur in individuals affected with chronic myocarditis/DCM manifesting myocardial dysfunctions. In these circumstances, autoimmunity is suspected, and antibodies to various autoantigens have been demonstrated, suggesting that immune therapies to suppress the autoimmune responses may be necessary. From this perspective, we endeavoured to determine whether or not the known viral causes are associated with development of autoimmune responses to cardiac antigens that include both cardiotropic and non‐cardiotropic viruses. If so, what their nature and significance are in developing chronic myocarditis resulting from viruses as primary triggers. [ABSTRACT FROM AUTHOR]

Appendix has a distinct abundance of lymphatic cells and serves as a reservoir of microbiota which helps to replenish the large intestine with healthy flora. And it is the primary site of IgA induction, which shapes the composition of the intestinal microbiota. Recent population-based cohort studies report that appendectomy is associated with an increased risk of acute myocardial infarction and ischemic heart disease. Here, whether appendectomy has an effect on the occurrence and development of coxsackievirus B3 (CVB3)−induced viral myocarditis is studied. 103 TCID50 CVB3 was inoculated i.p. into appendectomized and sham-operated mice. RNA levels of viral load and pro-inflammatory cytokines in the hearts and the intestine were detected by RT−PCR. Compared to sham-operated mice, appendectomized mice exhibited attenuated cardiac inflammation and improved cardiac function, which is associated with a systemic reduced viral load. Appendectomized mice also displayed a reduction in cardiac neutrophil and macrophage infiltration and pro-inflammatory cytokine production. Mechanistically, we found that CVB3 induced an early and potent IL-10 production in the cecal patch at 2 days post infection. Appendectomy significantly decreased intestinal IL-10 and IL-10+ CD4+ Treg frequency which led to a marked increase in intestinal (primary entry site for CVB3) anti-viral IFN-γ+ CD4+ T and IFN-γ+ CD8+ T response and viral restriction, eventually resulting in improved myocarditis. Our results suggest that appendix modulates cardiac infection and inflammation through regulating intestinal IL-10+ Treg response. [ABSTRACT FROM AUTHOR]

Viral myocarditis (VM) is a clinically common inflammatory disease. Accumulating literature has indicated that M2 macrophages protect mice from Coxsackievirus B3 (CVB3)-induced VM. However, mechanisms that underlie M2 macrophages alleviating myocardial inflammation remain largely undefined. We found that M2 macrophage-derived exosomes (M2-Exo) can effectively attenuate VM. The long non-coding RNA (lncRNA) AK083884 in M2-Exo was found to be involved in the regulation of macrophage polarization by exosome lncRNA sequencing combined with in vitro functional assays. M2-Exo-derived AK083884 promotes macrophage M2 polarization and protects mice from CVB3-induced VM. Furthermore, we identified pyruvate kinase M2 (PKM2) as a protein target binding to AK083884 and found that PKM2 knockdown could promote macrophages to polarize to M2 phenotype. Intriguingly, functional assay revealed that downregulation of AK083884 promotes metabolic reprogramming in macrophages. In addition, co-immunoprecipitation was performed to reveal AK083884 could interact with PKM2 and inhibition of AK083884 can facilitate the binding of PKM2 and HIF-1α. Collectively, our findings uncovered an important role of M2-Exo-derived AK083884 in the regulation of macrophage polarization through metabolic reprogramming, identified a new participant in the development of VM and provided a potential clinically important therapeutic target.

Dengue is a global public health concern, affecting around 50 million individuals and causing mortality in 20,000 patients per year. It is an arboviral disease caused by a single-stranded Ribonucleic Acid (RNA) virus belonging to the Flavivirus group and is transmitted by mosquitoes, specifically Aedes aegypti or albopictus. It comprises four serotypes, DENV1 to DENV4, and infection from one serotype only provides lifelong immunity for that subtype. Due to antibody-dependent enhancement, past infection with one serotype increases the prevalence of dengue haemorrhagic fever. The disease spectrum can range from asymptomatic infection to fever, fatal dengue haemorrhagic fever, or dengue shock syndrome. Due to improved disease knowledge, its involvement in the neurological system has been explored. Neurological abnormalities in dengue infection are rare and can be misdiagnosed due to other causes. Present case is of a young 23-year-old male with a history of fever 3-4 days prior, which later manifested with seizures and drowsiness. Despite emergency treatment, encephalitis and viral myocarditis developed, eventually leading to brain death within 24 hours of admission.

Abstract Background Acute viral myocarditis (AVMC) is an inflammatory disease of the myocardium. Evidence indicates that dysbiosis of gut microbiome and related metabolites intimately associated with cardiovascular diseases through the gut-heart axis. Methods We built mouse models of AVMC, then applied 16 S rDNA gene sequencing and UPLC-MS/MS metabolomics to explore variations of gut microbiome and disturbances of cardiac metabolic profiles. Results Compared with Control group, analysis of gut microbiota showed lower diversity in AVMC, decreased relative abundance of genera mainly belonging to the phyla Bacteroidetes, and increased of phyla Proteobacteria. Metabolomics analysis showed disturbances of cardiac metabolomics, including 62 increased and 84 decreased metabolites, and mainly assigned to lipid, amino acid, carbohydrate and nucleotide metabolism. The steroid hormone biosynthesis, cortisol synthesis and secretion pathway were particularly enriched in AVMC. Among them, such as estrone 3-sulfate, desoxycortone positively correlated with disturbed gut microbiome. Conclusion In summary, both the structure of the gut microbiome community and the cardiac metabolome were significantly changed in AVMC. Our findings suggest that gut microbiome may participate in the development of AVMC, the mechanism may be related to its role in dysregulated metabolites such as steroid hormone biosynthesis.

Abstract This case study aimed to identify rare viral myocarditis combined with encephalitis as a COVID‐19 vaccine complication. A 59‐year‐old male patient with a 2 day history of headache and rapidly progressive cognitive decline, who had received the third dose of COVID‐19 vaccine 12 days before, was admitted to our hospital. The patient had no underlying systemic conditions, no prior medical history, and no prior history of COVID‐19 infection. The patient was diagnosed with viral myocarditis and encephalitis by two neurologists and two cardiologists after laboratory examination, head computed tomography, and magnetic resonance imaging evaluation. The patient experienced cardiogenic shock and developed severe arrhythmia, resulting in his death 10 h after admission. Clinically suspected lethal viral myocarditis combined with encephalitis in the patient could be related to COVID‐19 vaccination. Adverse effects of the Chinese COVID‐19 vaccine, especially serious complications, have been uncommon. This case study highlights a rare complication after COVID‐19 vaccination that needs high attention.

ABSTRACTViral myocarditis is known to be a primary cause of dilated cardiomyopathy (DCM) that can lead to heart failure and sudden cardiac death and is invariably caused by myocardial viral infection following active inflammatory destruction of the myocardium. Although acute viral myocarditis frequently recovers on its own, current chronic myocarditis therapies are unsatisfactory, where the persistence of viral or immunological insults to the heart may play a role. Cellular and mouse experimental models that utilized the most prevalent Coxsackievirus group B type 3 (CVB3) virus infection causing myocarditis have illustrated the pathophysiology of viral myocarditis. In this review, immunological insights into the different stages of development of viral myocarditis were discussed, concentrating on the mechanisms of innate and adaptive immunity in the development of CVB3-induced myocarditis.

This study investigated the mechanisms of Jingfang Granule (JFG) in viral myocarditis (VMC) treatment via network pharmacology-based approach combined with molecular docking and validated the results through in vitro and in vivo experiments. The chemical composition of JFG and its therapeutic targets was queried in Traditional Chinese Medicine Systems Pharmacology (TCMSP) database. The targets related to VMC were retrieved from the disease database, and the overlapping targets were screened. Based on the STRING database, a protein–protein interaction network was constructed. Cytoscape software was used to construct the "component-target-disease" interaction network for visualization. GO and KEGG pathway enrichment analyses were performed using Metascape data. Molecular docking was performed using PyMoL2.3.0 and AutoDock Vina software programs. The target genes were further verified in vitro and in vivo. JFG contains 88 active components. The main biological targets of JFG in VMC include quercetin, luteolin, and kaempferol. The molecular docking results showed that the three key targets showed strong binding properties with both the height components of the molecular docking interaction energies. The results of experimental verification results showed that JFG may be used to treat VMC mainly by down-regulating inflammatory factors TNF-α and NF-κB and inhibiting myocardial apoptosis. The results support the network pharmacological data. JFG reduces myocardial inflammation and myocardial cell apoptosis in VMC and protects myocardial tissue. [ABSTRACT FROM AUTHOR]

The diagnosis and specific and causal treatment of myocarditis and inflammatory cardiomyopathy remain a major clinical challenge. Despite the rapid development of new imaging techniques, endomyocardial biopsies remain the gold standard for accurate diagnosis of inflammatory myocardial disease. With the introduction and continued development of immunohistochemical inflammation diagnostics in combination with viral nucleic acid testing, myocarditis diagnostics have improved significantly since their introduction. Together with new technologies such as miRNA and gene expression profiling, quantification of specific immune cell markers, and determination of viral activity, diagnostic accuracy and patient prognosis will continue to improve in the future. In this review, we summarize the current knowledge on the pathogenesis and diagnosis of myocarditis and inflammatory cardiomyopathies and highlight future perspectives for more in-depth and specialized biopsy diagnostics and precision, personalized medicine approaches. [ABSTRACT FROM AUTHOR]

Soluble interleukin 1 receptor-like 1 (sST2) is a novel predictor of poor outcomes, which is involved in inflammatory response and fibrosis of myocarditis. Cellular senescence is a state of irreversible cell cycle arrest. Studies have shown that senescence of myofibroblasts can limit or reduce cardiac fibrosis. However, the molecular mechanism of sST2 regulating cellular senescence is still unclear. Here, we investigate the role of sST2 on cellular senescence in cardiac fibrosis. Our results found that sST2 was upregulated in coxsackievirus group B type 3 (CVB3)-induced viral myocarditis (VMC), which correlated with the expression of senescence markers. In vitro, sST2 activated TGFβ signaling through the phosphorylation of the SMAD complex to induce mouse cardiac fibroblast (MCF) activation and inhibit cellular senescence by the Sirt1/p53/p21 signaling pathway. In vivo, anti-ST2 mAb attenuated CVB3-induced cardiac fibrosis. Our findings elucidate a crucial mechanism underlying through which sST2 inhibits cellular senescence and regulates MCF activation, providing a potential treatment strategy for cardiac fibrosis. [ABSTRACT FROM AUTHOR]

Although most patients with acute viral myocarditis recover spontaneously, some patients progress to heart failure. Perturbations in innate immunity may partially explain the heterogeneity of clinical outcomes. As the most abundant immune cells in the heart, cardiac macrophages have heterogeneous origins, including embryonic‐derived resident macrophages (ResMϕs) and monocyte‐derived macrophages (MoMFs). However, the time course change and role of cardiac macrophage subsets has not been fully explored. In the present study, we found that BALB/c mice had prolonged MoMF accumulation and low proportions of ResMϕs that could not be restored to normal levels. MoMFs of BALB/c mice generally exhibit an M1‐dominant functional phenotype. Moreover, the preferential depletion of MoMF by a C‐C chemokine receptor type 2 (CCR2) inhibitor resulted in improved acute myocarditis and chronic fibrosis, as well as the recovery of ResMϕs number and reduced CD4+ T cell expansion. Hence, immunomodulatory therapy that targets the balance among cardiac macrophages and modulates their function is expected to prevent the progression of cardiac injury to overt heart failure and improve adverse outcomes. [ABSTRACT FROM AUTHOR]

Dengue is a global public health concern, affecting around 50 million individuals and causing mortality in 20,000 patients per year. It is an arboviral disease caused by a single-stranded Ribonucleic Acid (RNA) virus belonging to the Flavivirus group and is transmitted by mosquitoes, specifically Aedes aegypti or albopictus. It comprises four serotypes, DENV1 to DENV4, and infection from one serotype only provides lifelong immunity for that subtype. Due to antibody-dependent enhancement, past infection with one serotype increases the prevalence of dengue haemorrhagic fever. The disease spectrum can range from asymptomatic infection to fever, fatal dengue haemorrhagic fever, or dengue shock syndrome. Due to improved disease knowledge, its involvement in the neurological system has been explored. Neurological abnormalities in dengue infection are rare and can be misdiagnosed due to other causes. Present case is of a young 23-year-old male with a history of fever 3-4 days prior, which later manifested with seizures and drowsiness. Despite emergency treatment, encephalitis and viral myocarditis developed, eventually leading to brain death within 24 hours of admission. [ABSTRACT FROM AUTHOR]

Viral myocarditis (VMC) is a common myocardial inflammatory disease characterized by inflammatory cell infiltration and cardiomyocyte necrosis. Sema3A was reported to reduce cardiac inflammation and improve cardiac function after myocardial infarction, but its role in VMC remains to be explored. Here, a VMC mouse model was established by infection with CVB3, and Sema3A was overexpressed in vivo by intraventricular injection of an adenovirus‐mediated Sema3A expression vector (Ad‐Sema3A). We found that Sema3A overexpression attenuated CVB3‐induced cardiac dysfunction and tissue inflammation. And Sema3A also reduced macrophage accumulation and NLRP3 inflammasome activation in the myocardium of VMC mice. In vitro, LPS was used to stimulate primary splenic macrophages to mimic the macrophage activation state in vivo. Activated macrophages were co‐cultured with primary mouse cardiomyocytes to evaluate macrophage infiltration‐induced cardiomyocyte damage. Ectopic expression of Sema3A in cardiomyocytes effectively protected cardiomyocytes from activated macrophage‐induced inflammation, apoptosis, and ROS accumulation. Mechanistically, cardiomyocyte‐expressed Sema3A mitigated macrophage infiltration‐caused cardiomyocyte dysfunction by promoting cardiomyocyte mitophagy and hindering NLRP3 inflammasome activation. Furthermore, NAM (a SIRT1 inhibitor) reversed the protective effect of Sema3A against activated macrophage‐induced cardiomyocyte dysfunction by suppressing cardiomyocyte mitophagy. In conclusion, Sema3A promoted cardiomyocyte mitophagy and suppressed inflammasome activation by regulating SIRT1, thereby attenuating macrophage infiltration‐induced cardiomyocyte injury in VMC. [ABSTRACT FROM AUTHOR]

Viral myocarditis (VMC), characterized by viral infection-induced inflammation, is a life-threatening disease associated with dilated cardiomyopathy or heart failure. Innate immunity plays a crucial role in the progression of inflammation, in which inflammasomes provide a platform for the secretion of cytokines and mediate pyroptosis. Inflammasomes are rising stars gaining increasing attention. The nucleotide oligomerization domain-, leucine-rich repeat-, and pyrin domaincontaining protein 3 (NLRP3) inflammasome, the caspase recruitment domaincontaining protein 8 (CARD8) inflammasome, and the caspase-11 inflammasome are three inflammasomes that were reported to affect the process and prognosis of VMC. These inflammasomes can be activated by a wide range of cellular events. Accumulating evidence has suggested that inflammasomes are involved in different stages of VMC, including the trigger and progression of myocardial injury and remodeling after infection. In this review, we summarized the pathways involving inflammasomes in VMC and discussed the potential therapies targeting inflammasomes and related pathways. [ABSTRACT FROM AUTHOR]

Background: Acute viral myocarditis (AVMC) is an inflammatory disease of the myocardium. Evidence indicates that dysbiosis of gut microbiome and related metabolites intimately associated with cardiovascular diseases through the gut-heart axis. Methods: We built mouse models of AVMC, then applied 16 S rDNA gene sequencing and UPLC-MS/MS metabolomics to explore variations of gut microbiome and disturbances of cardiac metabolic profiles. Results: Compared with Control group, analysis of gut microbiota showed lower diversity in AVMC, decreased relative abundance of genera mainly belonging to the phyla Bacteroidetes, and increased of phyla Proteobacteria. Metabolomics analysis showed disturbances of cardiac metabolomics, including 62 increased and 84 decreased metabolites, and mainly assigned to lipid, amino acid, carbohydrate and nucleotide metabolism. The steroid hormone biosynthesis, cortisol synthesis and secretion pathway were particularly enriched in AVMC. Among them, such as estrone 3-sulfate, desoxycortone positively correlated with disturbed gut microbiome. Conclusion: In summary, both the structure of the gut microbiome community and the cardiac metabolome were significantly changed in AVMC. Our findings suggest that gut microbiome may participate in the development of AVMC, the mechanism may be related to its role in dysregulated metabolites such as steroid hormone biosynthesis. [ABSTRACT FROM AUTHOR]

Viral myocarditis (VMC) is a common disease characterized by cardiac inflammation. AC-73, an inhibitor of CD147, disrupts the dimerization of CD147, which participates in the regulation of inflammation. To explore whether AC-73 could alleviate cardiac inflammation induced by CVB3, mice were injected intraperitoneally with AC-73 on the fourth day post-infection (dpi) and sacrificed on the seventh dpi. Pathological changes in the myocardium, T cell activation or differentiation, and expression of cytokines were analyzed using H&E staining, flow cytometry, fluorescence staining and multiplex immunoassay. The results showed that AC-73 alleviated cardiac pathological injury and downregulated the percentage of CD45+CD3+ T cells in the CVB3-infected mice. The administration of AC-73 reduced the percentage of activated CD4+ and CD8+ T cells (CD69+ and/or CD38+) in the spleen, while the percentage of CD4+ T cell subsets in the spleen was not changed in the CVB3-infected mice. In addition, the infiltration of activated T cells (CD69+) and macrophages (F4/80+) in the myocardium also decreased after the AC-73 treatment. The results also showed that AC-73 inhibited the release of many cytokines and chemokines in the plasma of the CVB3-infected mice. In conclusion, AC-73 mitigated CVB3-induced myocarditis by inhibiting the activation of T cells and the recruitment of immune cells to the heart. Thus, CD147 may be a therapeutic target for virus-induced cardiac inflammation. [ABSTRACT FROM AUTHOR]

This case study aimed to identify rare viral myocarditis combined with encephalitis as a COVID‐19 vaccine complication. A 59‐year‐old male patient with a 2 day history of headache and rapidly progressive cognitive decline, who had received the third dose of COVID‐19 vaccine 12 days before, was admitted to our hospital. The patient had no underlying systemic conditions, no prior medical history, and no prior history of COVID‐19 infection. The patient was diagnosed with viral myocarditis and encephalitis by two neurologists and two cardiologists after laboratory examination, head computed tomography, and magnetic resonance imaging evaluation. The patient experienced cardiogenic shock and developed severe arrhythmia, resulting in his death 10 h after admission. Clinically suspected lethal viral myocarditis combined with encephalitis in the patient could be related to COVID‐19 vaccination. Adverse effects of the Chinese COVID‐19 vaccine, especially serious complications, have been uncommon. This case study highlights a rare complication after COVID‐19 vaccination that needs high attention. [ABSTRACT FROM AUTHOR]

Coronavirus disease 2019 (COVID-19) is a pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). COVID-19 is defined by respiratory symptoms, but cardiac complications including viral myocarditis are also prevalent. Although ischemic and inflammatory responses caused by COVID-19 can detrimentally affect cardiac function, the direct impact of SARS-CoV-2 infection on human cardiomyocytes is not well understood. Here, we utilize human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) as a model to examine the mechanisms of cardiomyocyte-specific infection by SARS-CoV-2. Microscopy and RNA sequencing demonstrate that SARS-CoV-2 can enter hiPSC-CMs via ACE2. Viral replication and cytopathic effect induce hiPSC-CM apoptosis and cessation of beating after 72 h of infection. SARS-CoV-2 infection activates innate immune response and antiviral clearance gene pathways, while inhibiting metabolic pathways and suppressing ACE2 expression. These studies show that SARS-CoV-2 can infect hiPSC-CMs in vitro, establishing a model for elucidating infection mechanisms and potentially a cardiac-specific antiviral drug screening platform.