An overview of the immune mechanisms of viral myocarditis

Clinical Effect Analysis of Different Doses of Creatine Phosphate Sodium Combined with Immunoglobulin in the Treatment of Pediatric Viral Myocarditis

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.

Ivermectin ameliorates acute myocarditis via the inhibition of importin-mediated nuclear translocation of NF-κB/p65

BACKGROUND

Myocarditis is an important clinical issue which lacks specific treatment by now. Ivermectin (IVM) is an inhibitor of importin α/β-mediated nuclear translocation. This study aimed to explore the therapeutic effects of IVM on acute myocarditis.

METHODS

Mouse models of coxsackie B3 virus (CVB3) infection-induced myocarditis and experimental autoimmune myocarditis (EAM) were established to evaluate the effects of IVM. Cardiac functions were evaluated by echocardiography and Millar catheter. Cardiac inflammatory infiltration was assessed by histological staining. Cytometric bead array and quantitative real-time PCR were used to detect the levels of pro-inflammatory cytokines. The macrophages and their M1/M2 polarization were analyzed via flow cytometry. Protein expression and binding were detected by co-immunoprecipitation, Western blotting and histological staining. The underlying mechanism was verified in vitro using CVB3-infected RAW264.7 macrophages. Cyclic polypeptide (cTN50) was synthesized to selectively inhibit the nuclear translocation of NF-κB/p65, and CVB3-infected RAW264.7 cells were treated with cTN50.

RESULTS

Increased expression of importin β was observed in both models. IVM treatment improved cardiac functions and reduced the cardiac inflammation associated with CVB3-myocarditis and EAM. Furthermore, the pro-inflammatory cytokine (IL-1β/IL-6/TNF-α) levels were downregulated via the inhibition of the nuclear translocation of NF-κB/p65 in macrophages. IVM and cTN50 treatment also inhibited the nuclear translocation of NF-κB/p65 and downregulated the expression of pro-inflammatory cytokines in RAW264.7 macrophages.

CONCLUSIONS

Ivermectin inhibits the nuclear translocation of NF-κB/p65 and the expression of major pro-inflammatory cytokines in myocarditis. The therapeutic effects of IVM on viral and non-viral myocarditis models suggest its potential application in the treatment of acute myocarditis.

The roles of B cells in cardiovascular diseases

Damage to the heart can start the repair process and cause cardiac remodeling. B cells play an important role in this process. B cells are recruited to the injured place and activate cardiac remodeling through secreting antibodies and cytokines. Different types of B cells showed specific functions in the heart. Among all types of B cells, heart-associated B cells play a vital role in the heart by secreting TGFβ1. B cells participate in the activation of fibroblasts and promote cardiac fibrosis. Four subtypes of B cells in the heart revealed the relationship between the B cells' heterogeneity and cardiac remodeling. Many cardiovascular diseases like atherosclerosis, heart failure (HF), hypertension, myocardial infarction (MI), and dilated cardiomyopathy (DCM) are related to B cells. The primary mechanisms of these B cell-related activities will be discussed in this review, which may also suggest potential novel therapeutic targets.

Abundant Neutrophil-Initiated Acute Myocardial Injury Following Coxsackievirus A6 Infection

Coxsackievirus A6 (CVA6) is currently considered as a predominant pathogen of hand, foot, and mouth disease (HFMD), and is occasionally linked to myocardial injury. We first established a mouse model of CVA6-induced myocardial injury. Next, we analyzed the immune cell phenotypes CVA6-infected mice hearts by fluorescence-activated cell sorting, and found that CVA6 led to massive neutrophils infiltration, suggesting their potential link with the occurrence of myocardial injury. We further used either αGr-1 or αLy6G antibody to deplete neutrophils, and found that neutrophil-depleted animals showed decreased cardiac enzymes, lower degree of pathology in hearts, and reduced inflammatory cytokine production compared to isotype controls. Finally, we confirmed the involvement of neutrophils in myocardial injury of clinical patients with severe HFMD. Our study suggests that excessive neutrophils contribute to myocardial injury caused by CVA6 infection, which provides new insights into myocardial injury during the development of HFMD severity and the outcome of immune cell-mediated therapies.

Tissue-specific features of innate lymphoid cells in antiviral defense

Innate lymphocytes (ILCs) rapidly respond to and protect against invading pathogens and cancer. ILCs include natural killer (NK) cells, ILC1s, ILC2s, ILC3s, and lymphoid tissue inducer (LTi) cells and include type I, type II, and type III immune cells. While NK cells have been well recognized for their role in antiviral immunity, other ILC subtypes are emerging as players in antiviral defense. Each ILC subset has specialized functions that uniquely impact the antiviral immunity and health of the host depending on the tissue microenvironment. This review focuses on the specialized functions of each ILC subtype and their roles in antiviral immune responses across tissues. Several viruses within infection-prone tissues will be highlighted to provide an overview of the extent of the ILC immunity within tissues and emphasize common versus virus-specific responses.

Loss of TRIM29 mitigates viral myocarditis by attenuating PERK-driven ER stress response in male mice

Viral myocarditis, an inflammatory disease of the myocardium, is a significant cause of sudden death in children and young adults. The current coronavirus disease 19 pandemic emphasizes the need to understand the pathogenesis mechanisms and potential treatment strategies for viral myocarditis. Here, we found that TRIM29 was highly induced by cardiotropic viruses and promoted protein kinase RNA-like endoplasmic reticulum kinase (PERK)-mediated endoplasmic reticulum (ER) stress, apoptosis, and reactive oxygen species (ROS) responses that promote viral replication in cardiomyocytes in vitro. TRIM29 deficiency protected mice from viral myocarditis by promoting cardiac antiviral functions and reducing PERK-mediated inflammation and immunosuppressive monocytic myeloid-derived suppressor cells (mMDSC) in vivo. Mechanistically, TRIM29 interacted with PERK to promote SUMOylation of PERK to maintain its stability, thereby promoting PERK-mediated signaling pathways. Finally, we demonstrated that the PERK inhibitor GSK2656157 mitigated viral myocarditis by disrupting the TRIM29-PERK connection, thereby bolstering cardiac function, enhancing cardiac antiviral responses, and curbing inflammation and immunosuppressive mMDSC in vivo. Our findings offer insight into how cardiotropic viruses exploit TRIM29-regulated PERK signaling pathways to instigate viral myocarditis, suggesting that targeting the TRIM29-PERK axis could mitigate disease severity.

miR-29b-3p regulates cardiomyocytes pyroptosis in CVB3-induced myocarditis through targeting DNMT3A

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.

Endoplasmic reticulum stress-related gene expression causes the progression of dilated cardiomyopathy by inducing apoptosis

Background: Previous studies have shown that endoplasmic reticulum stress (ERS) -induced apoptosis is involved in the pathogenesis of dilated cardiomyopathy (DCM). However, the molecular mechanism involved has not been fully characterized. Results: In total, eight genes were obtained at the intersection of 1,068 differentially expressed genes (DEGs) from differential expression analysis between DCM and healthy control (HC) samples, 320 module genes from weighted gene co-expression network analysis (WGCNA), and 2,009 endoplasmic reticulum stress (ERGs). These eight genes were found to be associated with immunity and angiogenesis. Four of these genes were related to apoptosis. The upregulation of MX1 may represent an autocompensatory response to DCM caused by a virus that inhibits viral RNA and DNA synthesis, while acting as an autoimmune antigen and inducing apoptosis. The upregulation of TESPA1 would lead to the dysfunction of calcium release from the endoplasmic reticulum. The upregulation of THBS4 would affect macrophage differentiation and apoptosis, consistent with inflammation and fibrosis of cardiomyocytes in DCM. The downregulation of MYH6 would lead to dysfunction of the sarcomere, further explaining cardiac remodeling in DCM. Moreover, the expression of genes affecting the immune micro-environment was significantly altered, including TGF-β family member. Analysis of the co-expression and competitive endogenous RNA (ceRNA) network identified XIST, which competitively binds seven target microRNAs (miRNAs) and regulates MX1 and THBS4 expression. Finally, bisphenol A and valproic acid were found to target MX1, MYH6, and THBS4. Conclusion: We have identified four ERS-related genes (MX1, MYH6, TESPA1, and THBS4) that are dysregulated in DCM and related to apoptosis. This finding should help deepen understanding of the role of endoplasmic reticulum stress-induced apoptosis in the development of DCM.

Coxsackievirus B3 HFMD animal models in Syrian hamster and rhesus monkey

Coxsackievirus B3 (CVB3) is the pathogen causing hand, foot and mouth disease (HFMD), which manifests across a spectrum of clinical severity from mild to severe. However, CVB3-infected mouse models mainly demonstrate viral myocarditis and pancreatitis, failing to replicate human HFMD symptoms. Although several enteroviruses have been evaluated in Syrian hamsters and rhesus monkeys, there is no comprehensive data on CVB3. In this study, we have first tested the susceptibility of Syrian hamsters to CVB3 infection via different routes. The results showed that Syrian hamsters were successfully infected with CVB3 by intraperitoneal injection or nasal drip, leading to nasopharyngeal colonization, acute severe pathological injury, and typical HFMD symptoms. Notably, the nasal drip group exhibited a longer viral excretion cycle and more severe pathological damage. In the subsequent study, rhesus monkeys infected with CVB3 through nasal drips also presented signs of HFMD symptoms, viral excretion, serum antibody conversion, viral nucleic acids and antigens, and the specific organ damages, particularly in the heart. Surprisingly, there were no significant differences in myocardial enzyme levels, and the clinical symptoms resembled those often associated with common, mild infections. In summary, the study successfully developed severe Syrian hamsters and mild rhesus monkey models for CVB3-induced HFMD. These models could serve as a basis for understanding the disease pathogenesis, conducting pre-trial prevention and evaluation, and implementing post-exposure intervention.

Repurposing of rituximab biosimilars to treat B cell mediated autoimmune diseases

Rituximab, the first monoclonal antibody approved for the treatment of lymphoma, eventually became one of the most popular and versatile drugs ever in terms of clinical application and revenue. Since its patent expiration, and consequently, the loss of exclusivity of the original biologic, its repurposing as an off-label drug has increased dramatically, propelled by the development and commercialization of its many biosimilars. Currently, rituximab is prescribed worldwide to treat a vast range of autoimmune diseases mediated by B cells. Here, we present a comprehensive overview of rituximab repurposing in 115 autoimmune diseases across 17 medical specialties, sourced from over 1530 publications. Our work highlights the extent of its off-label use and clinical benefits, underlining the success of rituximab repurposing for both common and orphan immune-related diseases. We discuss the scientific mechanism associated with its clinical efficacy and provide additional indications for which rituximab could be investigated. Our study presents rituximab as a flagship example of drug repurposing owing to its central role in targeting cluster of differentiate 20 positive (CD20) B cells in 115 autoimmune diseases.

Diagnostic challenges and forensic implications in a case of infantile fatal myocarditis

We present the case of a 23-month-old child who died less than 24 h after the onset of cardiac symptoms, despite being admitted to the hospital 72 h earlier. Autopsy revealed no significant macroscopic changes, and histologic examination revealed focal lymphocytic myocarditis with myocyte disruption, diffuse alveolar damage in the exudative phase, and generalized lymphocytic immune activation in other organs. Ante-mortem and post-mortem microbiological exams did not clearly prove a causative role of infectious agents. The peculiarity of this case was characterized by the contrast between the severe clinical features and the mild cardiac histological findings. This discrepancy, coupled with the suspicion of a viral causative role based on both ante-mortem and post-mortem microbiological examinations, presented significant challenges in reaching an etiological diagnosis. This case also confirms that the diagnosis of myocarditis in children cannot be made solely on the basis of histological cut-offs or microbiological results. Using abductive reasoning, various diagnostic hypotheses were formulated and evaluated to arrive at the final diagnosis of fatal myocarditis of viral or post-viral origin. Data from post-mortem examination are often the only source of information that is available to the experts, especially in cases of sudden infant death syndrome. In such cases, the forensic pathologists should accurately evaluate findings that may appear to indicate a different etiology, and, in the absence of clinical or radiological data, interpret post-mortem data in a logically correct manner. The autopsy is the first essential step to evaluate the cause of death and must be integrated with the results of ante- and post-mortem diagnostic tests in a holistic approach, which is crucial to allow forensic pathologists to provide an appropriate and relevant opinion.

Empagliflozin attenuates inflammation levels in autoimmune myocarditis through the STAT3 pathway and macrophage phenotype transformation

OBJECTIVE

To investigate the anti-inflammatory actions and molecular mechanisms of the sodium/glucose cotransporter 2 (SGLT-2) inhibitor empagliflozin on autoimmune myocarditis.

METHODS

The experimental autoimmune myocarditis (EAM) mouse model was constructed using peptides, and the therapeutic effects of empagliflozin on cardiac inflammation and fibrosis were observed using hematoxylin and eosin (HE), Sirius red staining, and Masson's trichome staining. Western blotting was used to identify the actions of empagliflozin on the surface marker expression levels of M2 macrophages and inflammatory factors. In vitro, experiments were completed using lentiviral overexpression of SGLT-2 in macrophages. Macrophage inflammation and anti-inflammatory models were constructed using lipopolysaccharide and interleukin-4, respectively. Enzyme-linked immunosorbent assay, immunofluorescence staining, and reverse-transcription polymerase chain reaction were applied to detect the effects of empagliflozin on the levels of inflammatory factors and macrophage surface markers. Western blotting was used to identify variability in SGLT-2 expression and the role of empagliflozin on the signal transducer and activator of the transcription 3 (STAT3) pathway. The Genomic Spatial Event 142564 dataset was studied in an EAM mouse model. We selected single-cell sequencing results from day 0 and day 21 of modeling to visualize differentially expressed genes. Immune cell infiltration correlation analysis was implemented to explore the expression of inflammatory factors and phenotypic markers.

RESULTS

Empagliflozin increased the expression of the M2 macrophage surface marker CD206 and reduced the level of inflammatory factors in the EAM mouse model while reducing the levels of inflammation and fibrosis. In vitro experiments revealed that the phosphorylation of STAT3 pathway was enhanced after macrophages were polarized to M1 phenotype by LPS, the phosphorylation of STAT3 pathway was inhibited after empagliflozin intervention, and the levels of inflammatory factors were decreased.

CONCLUSION

Empagliflozin can reduce the level of inflammation in autoimmune myocarditis through the STAT3 pathway and macrophage phenotype transformation. These results indicate the expression of SGLT-2 can be a target for autoimmune myocarditis therapy.

Immune checkpoint inhibitors break whose heart? Perspectives from cardio-immuno-oncology

Immune checkpoint inhibitors (ICIs) are monoclonal antibody antagonists, which can block cytotoxic T lymphocyte antigen-4 (CTLA-4), programmed death-1/ligand-1 (PD-1/PD-L1) pathways, and other molecules exploited by tumor cells to evade T cell-mediated immune response. ICIs have transformed the treatment landscape for various cancers due to their amazing efficacy. Many anti-tumor therapies, including targeted therapy, radiotherapy, and chemotherapy, combine ICIs to make the treatment more effective. However, the off-target immune activation caused by ICIs may lead to a broad spectrum of immune-related adverse events (irAEs) affecting multiple organ systems. Among irAEs, cardiotoxicity induced by ICIs, uncommon but fatal, has greatly offset survival benefits from ICIs, which is heartbreaking for both patients and clinicians. Consequently, such cardiotoxicity requires special vigilance, and it has become a common challenge both for patients and clinicians. This article reviewed the clinical manifestations and influence of cardiotoxicity from the view of patients and clinicians, elaborated on the underlying mechanisms in conjunction with animal studies, and then attempted to propose management strategies from a cardio-immuno-oncology multidisciplinary perspective.

The inflammatory spectrum of cardiomyopathies

Infiltration of the myocardium with various cell types, cytokines and chemokines plays a crucial role in the pathogenesis of cardiomyopathies including inflammatory cardiomyopathies and myocarditis. A more comprehensive understanding of the precise immune mechanisms involved in acute and chronic myocarditis is essential to develop novel therapeutic approaches. This review offers a comprehensive overview of the current knowledge of the immune landscape in cardiomyopathies based on etiology. It identifies gaps in our knowledge about cardiac inflammation and emphasizes the need for new translational approaches to improve our understanding thus enabling development of novel early detection methods and more effective treatments.

Identification of the communal pathogenesis and immune landscape between viral myocarditis and dilated cardiomyopathy

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.

Myocarditis: A multi-omics approach

Myocarditis, an inflammatory condition of weakened heart muscles often triggered by a variety of causes, that can result in heart failure and sudden death. Novel ways to enhance our understanding of myocarditis pathogenesis is available through newer modalities (omics). In this review, we examine the roles of various biomolecules and associated functional pathways across genomics, transcriptomics, proteomics, and metabolomics in the pathogenesis of myocarditis. Our analysis further explores the reproducibility and variability intrinsic to omics studies, underscoring the necessity and significance of employing a multi-omics approach to gain profound insights into myocarditis pathogenesis. This integrated strategy not only enhances our understanding of the disease, but also confirms the critical importance of a holistic multi-omics approach in disease analysis.

CD4+TEM cells drive the progression from acute myocarditis to dilated cardiomyopathy in CVB3-induced BALB/c mice

Acute viral myocarditis can progress to chronic myocarditis leading to dilated cardiomyopathy (DCM). Persistent CD4+ T-cell-mediated autoimmunity triggered by infection plays a critical role in this progression. Increasing evidence demonstrates that effector memory CD4+T (CD4+TEM) cells, a subset of memory CD4+ T cells, are crucial pathogenic mediators of many autoimmune diseases. However, the role of CD4+TEM cells during the progression from acute viral myocarditis to DCM remains unknown. In this study, we observed an increase in CD4+TEM cells both in the periphery and the heart, and memory CD4+ T cells were the predominant sources of IL-17A and IFN-γ among inflamed heart-infiltrating CD4+ T cells during the progression from acute myocarditis to chronic myocarditis and DCM in CVB3-induced BALB/c mice. Moreover, splenic CD4+TEM cells sorted from DCM mice induced by CVB3 were found to respond to cardiac self-antigens ex vivo. Additionally, adoptive transfer experiments substantiated their pathogenic impact, inducing sustained myocardial inflammation, tissue fibrosis, cardiac injury, and impairment of cardiac systolic function in vivo. Our findings illustrate that long-lived CD4+TEM cells are important contributors to the progression from acute viral myocarditis into DCM.

Role of immune cells in the pathogenesis of myocarditis

Myocarditis is an inflammatory heart disease that mostly affects young people. Myocarditis involves a complex immune network; however, its detailed pathogenesis is currently unclear. The diversity and plasticity of immune cells, either in the peripheral blood or in the heart, have been partially revealed in a number of previous studies involving patients and several kinds of animal models with myocarditis. It is the complexity of immune cells, rather than one cell type that is the culprit. Thus, recognizing the individual intricacies within immune cells in the context of myocarditis pathogenesis and finding the key intersection of the immune network may help in the diagnosis and treatment of this condition. With the vast amount of cell data gained on myocarditis and the recent application of single-cell sequencing, we summarize the multiple functions of currently recognized key immune cells in the pathogenesis of myocarditis to provide an immune background for subsequent investigations.

Macrophage CAPN4 regulates CVB3-induced cardiac inflammation and injury by promoting NLRP3 inflammasome activation and phenotypic transformation to the inflammatory subtype

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.

Critical diseases in neonates after discharge home from birth hospital: A retrospective study from a tertiary hospital in Japan

INTRODUCTION

To establish actionable neonatal screening during the first month of life, we investigated critical diseases in seemingly healthy newborns discharged from birth hospitals.

METHODS

This retrospective study enrolled previously healthy full-term infants who visited our hospital, a tertiary hospital in Japan, from home between 5 and 28 days after birth from 2009 to 2018. Infants with known perinatal or congenital diseases, positive newborn screening results, or accidental injuries were excluded. Data were collected from electronic medical records, including principal diagnosis, clinical details, and prognosis at 18 months of age.

RESULTS

Ninety-seven (58 %) of 168 eligible neonates were admitted to the hospital, and 71 (42 %) were not. The median admission rate in patients with disease onset at ≤14 days after birth (80 %) was significantly higher than that in patients with disease onset at ≥15 days (42 %). Among 45 patients who received intensive medical care, 5 died and 10 developed neurodevelopmental sequelae. Four of 5 patients died by 100 days. Among 25 diseases treated in intensive care unit, 17 (68 %) diseases had a prevalence of <1 per 2000 live births. The commonly used diagnostic methods were imaging (n = 58, 35 %) and physical examination (n = 34, 20 %).

CONCLUSION

Critical diseases due to rare and heterogeneous causes in ostensibly healthy newborns occurred predominantly in the first two weeks of life. Optimal newborn screening and health check-up protocols may benefit from the wide spectrum of life-threatening diseases occurring in home after birth.

Epoxyeicosatrienoic Acids Prevent Cardiac Dysfunction in Viral Myocarditis via Interferon Type I Signaling

Myocarditis is a challenging inflammatory disease of the heart, and better understanding of its pathogenesis is needed to develop specific drug therapies. Epoxyeicosatrienoic acids (EETs), active molecules synthesized by CYP (cytochrome P450) enzymes from arachidonic acids and hydrolyzed to less active dihydroxyeicosatrienoic acids by sEH (soluble epoxide hydrolase), have been attributed anti-inflammatory activity. Here, we investigated whether EETs have immunomodulatory activity and exert protective effects on coxsackie B3 virus-induced myocarditis. Viral infection altered eicosanoid epoxide and diol levels in both patients with myocarditis and in the murine heart and correlated with the increased expression and activity of sEH after coxsackie B3 virus infection. Administration of a sEH inhibitor prevented coxsackie B3 virus-induced cardiac dysfunction and inflammatory infiltration. Importantly, EET/sEH inhibitor treatment attenuated viral infection or improved viral resistance by activating type I IFN (interferon) signaling. At the molecular level, EETs enhanced the interaction between GSK3β (glycogen synthase kinase-3 beta) and TBK1 (TANK-binding kinase 1) to promote IFN-β production. Our findings revealed that EETs and sEH inhibitors prevent the progress of coxsackie B3 virus-induced myocarditis, particularly by promoting viral resistance by increasing IFN production.

Appendectomy Mitigates Coxsackievirus B3-Induced Viral Myocarditis

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.

Cardiac miR-19a/19b was induced and hijacked by CVB3 to facilitate virus replication via targeting viral genomic RdRp-encoding region

Coxsackievirus B3 (CVB3) is one of the major pathogens of viral myocarditis, lacking specific anti-virus therapeutic options. Increasing evidence has shown an important involvement of the miR-17-92 cluster both in virus infection and cardiovascular development and diseases, while its role in CVB3-induced viral myocarditis remains unclear. In this study, we found that miR-19a and miR-19b were significantly up-regulated in heart tissues of CVB3-infected mice and exerted a significant facilitatory impact on CVB3 biosynthesis and replication, with a more pronounced effect observed in miR-19b, by targeting the encoding region of viral RNA-dependent RNA polymerase 3D (RdRp, 3Dpol) to increase viral genomic RNA stability. The virus-promoting effects were nullified by the synonymous mutations in the viral 3Dpol-encoding region, which corresponded to the seed sequence shared by miR-19a and miR-19b. In parallel, treatment with miR-19b antagomir not only resulted in a noteworthy suppression of CVB3 replication and infection in infected cells, but also demonstrated a significant reduction in the cardiac viral load of CVB3-infected mice, resulting in a considerable alleviation of myocarditis. Collectively, our study showed that CVB3-induced cardiac miR-19a/19b contributed to viral myocarditis via facilitating virus biosynthesis and replication, and targeting miR-19a/19b might represent a novel therapeutic target for CVB3-induced viral myocarditis.

Immunopathogenesis and immunomodulatory therapy for myocarditis

Myocarditis is an inflammatory cardiac disease characterized by the destruction of myocardial cells, infiltration of interstitial inflammatory cells, and fibrosis, and is becoming a major public health concern. The aetiology of myocarditis continues to broaden as new pathogens and drugs emerge. The relationship between immune checkpoint inhibitors, severe acute respiratory syndrome coronavirus 2, vaccines against coronavirus disease-2019, and myocarditis has attracted increased attention. Immunopathological processes play an important role in the different phases of myocarditis, affecting disease occurrence, development, and prognosis. Excessive immune activation can induce severe myocardial injury and lead to fulminant myocarditis, whereas chronic inflammation can lead to cardiac remodelling and inflammatory dilated cardiomyopathy. The use of immunosuppressive treatments, particularly cytotoxic agents, for myocarditis, remains controversial. While reasonable and effective immunomodulatory therapy is the general trend. This review focuses on the current understanding of the aetiology and immunopathogenesis of myocarditis and offers new perspectives on immunomodulatory therapies.

Infection by exosome-carried Coxsackievirus B3 induces immune escape resulting in an aggravated pathogenesis

Increasing evidence has shown that extracellular vesicles or exosomes released from virus-infected cells contain viral particles, genomes, or other pathogenic factors that move to neighbor cells, contributing to virus dissemination and productive infection. Our recent study demonstrated that exosomes carrying CVB3 virions exhibited greater infection efficiency than free virions because they accessed various entry routes, overcoming restrictions to viral tropism. However, the pathogenicity of exosomes carried CVB3 and their effect on immunological properties have not yet been completely explained. In the current study, we sought to explore whether exosomes exert their effect on the CVB3-induced pathogenesis or evade the immune attack. Our results showed that exosomes-carried CVB3 could effectively infect viral receptor-negative immune cells in vivo, resulting in inducing immune system loss. Importantly, the exosomes-carried CVB3 had the ability to escape the neutralizing antibodies activity resulting in inducing the severe onset of myocarditis. Using the genetically engineered mouse with deficiency of exosomes, we observed that the exosomes-carried CVB3 reinforced an aggravated pathogenesis. By understanding how exosomes promote the course of viral disease, clinical applications of exosomes can be developed.

Myocarditis: Etiology, Pathogenesis, and Their Implications in Clinical Practice

Myocarditis is an inflammatory disease of the myocardium caused by infectious or non-infectious agents. It can lead to serious short-term and long-term sequalae, such as sudden cardiac death or dilated cardiomyopathy. Due to its heterogenous clinical presentation and disease course, challenging diagnosis and limited evidence for prognostic stratification, myocarditis poses a great challenge to clinicians. As it stands, the pathogenesis and etiology of myocarditis is only partially understood. Moreover, the impact of certain clinical features on risk assessment, patient outcomes and treatment options is not entirely clear. Such data, however, are essential in order to personalize patient care and implement novel therapeutic strategies. In this review, we discuss the possible etiologies of myocarditis, outline the key processes governing its pathogenesis and summarize best available evidence regarding patient outcomes and state-of-the-art therapeutic approaches.

Sema3A alleviates viral myocarditis by modulating SIRT1 to regulate cardiomyocyte mitophagy

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.

A combination of Sophora flavescens alkaloids and Panax quinquefolium saponins attenuates coxsackievirus B3‑induced acute myocarditis in mice via NF‑κB signaling

Timely treatment of viral myocarditis (VMC), a form of cardiac inflammation caused by viral infections, can reduce the occurrence of dilated cardiomyopathy and sudden death. Our previous study demonstrated the anti-inflammatory and anti-fibrotic effects of KX, a combination of Sophora flavescens alkaloids and Panax quinquefolium saponins, on an autoimmune myocarditis model in vivo. The present study explored the effects of KX on coxsackievirus B3 (CVB3)-induced acute VMC in mice. Mice were randomly divided into four groups: Control, VMC, KX-high (275 mg/kg) and KX-low (138 mg/kg). Mice in the VMC, KX-high and KX-low groups received injections of CVB3 to establish the VMC model, and those in the KX-high and KX-low groups also received KX by gavage (10 ml/kg) 2 h after virus injection until euthanasia was performed on day 7 or 21. Mice in the control group received an equal KX volume of purified water. The levels of lactate dehydrogenase (LDH), creatine kinase-myocardial band (CK-MB), cardiac troponin I (cTn-I), IL-1β, IL-6, TNF-α and high-sensitive C-reactive protein (hs-CRP) in mouse serum was measured using ELISA. Myocardial tissue structure and degree of injury were observed using hematoxylin and eosin staining. Western blotting and reverse transcription-quantitative PCR were performed to detect the expression levels of NF-κB pathway-related mRNA and protein in myocardial tissue. The results showed that the inflammation and myocardial damage levels of the mice in the VMC group were higher at 7 days than those at 21 days. At both 7 and 21 days, KX decreased the serum CK-MB, LDH, cTn-I, IL-6, TNF-α and hs-CRP levels, and inhibited NF-κB pathway-related mRNA and protein expression in the myocardium of mice. These findings indicated that KX may reduce the inflammatory response and attenuate the pathological damage in the acute and subacute phases of CVB3-induced VMC through the NF-κB pathway.

Viral Heart Disease: Diagnosis, Management, and Mechanisms

"Viral heart disease" is a term encompassing numerous virus-triggered heart conditions, wherein cardiac myocytes are injured, causing contractile dysfunction, cell death, or both. Cardiotropic viruses may also damage interstitial cells and vascular cells. Clinical presentation of the disorder varies widely. In most cases, patients are asymptomatic. Presentation includes-but is not limited to-flu-like symptoms, chest pain, cardiac arrhythmias, heart failure, cardiogenic shock, and sudden cardiac death. Laboratory studies, including blood-based heart injury indicators and cardiac imaging, may be needed. Management of viral heart disease requires a graded approach. Watchful observation at home may be the first step. Closer observation, with additional testing such as echocardiography in the clinic or hospital is less common yet may inform the use of cardiac magnetic resonance imaging. Intensive care may be indicated in severe acute illness. Viral heart disease mechanisms are complex. Initially, damage is predominantly virus mediated, whereas, in the second week, immune responses bring unintended obverse consequences for the myocardium. Innate immunity is largely beneficial in initial attempts to quell viral replication, whereas adaptive immunity brings helpful and antigen-specific mechanisms to fight the pathogen but also introduces the capability of autoimmunity. Each cardiotropic virus family has its own pathogenesis signature, including attack on myocytes, vascular cells, and other constitutive cells of myocardial interstitium. The stage of disease and preponderant viral pathways lend opportunities for potential intervention but also the likelihood of uncertainty about management. Overall, this review provides a novel glimpse into the depth of and need for solutions in viral heart disease.

Alterations of the gut microbiome and metabolic profile in CVB3-induced mice acute viral myocarditis

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.

SARS-CoV-2 induces cardiomyocyte apoptosis and inflammation but can be ameliorated by ACE inhibitor Captopril

Although the clinical manifestation of COVID-19 is mainly respiratory symptoms, approximately 20% of patients suffer from cardiac complications. COVID-19 patients with cardiovascular disease have higher severity of myocardial injury and poor outcomes. The underlying mechanism of myocardial injury caused by SARS-CoV-2 infection remains unclear. Using a non-transgenic mouse model infected with Beta variant (B.1.351), we found that the viral RNA could be detected in lungs and hearts of infected mice. Pathological analysis showed thinner ventricular wall, disorganized and ruptured myocardial fiber, mild inflammatory infiltration, and mild epicardia or interstitial fibrosis in hearts of infected mice. We also found that SARS-CoV-2 could infect cardiomyocytes and produce infectious progeny viruses in human pluripotent stem cell-derived cardiomyocyte-like cells (hPSC-CMs). SARS-CoV-2 infection caused apoptosis, reduction of mitochondrial integrity and quantity, and cessation of beating in hPSC-CMs. In order to dissect the mechanism of myocardial injury caused by SARS-CoV-2 infection, we employed transcriptome sequencing of hPSC-CMs at different time points after viral infection. Transcriptome analysis showed robust induction of inflammatory cytokines and chemokines, up-regulation of MHC class I molecules, activation of apoptosis signaling and cell cycle arresting. These may cause aggravate inflammation, immune cell infiltration, and cell death. Furthermore, we found that Captopril (hypotensive drugs targeting ACE) treatment could alleviate SARS-CoV-2 induced inflammatory response and apoptosis in cardiomyocytes via inactivating TNF signaling pathways, suggesting Captopril may be beneficial for reducing COVID-19 associated cardiomyopathy. These findings preliminarily explain the molecular mechanism of pathological cardiac injury caused by SARS-CoV-2 infection, providing new perspectives for the discovery of antiviral therapeutics.

Roles of inflammasomes in viral myocarditis

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 domain-containing protein 3 (NLRP3) inflammasome, the caspase recruitment domain-containing 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.

Role of Coxsackievirus B3-Induced Immune Responses in the Transition from Myocarditis to Dilated Cardiomyopathy and Heart Failure

Dilated cardiomyopathy (DCM) is a cardiac disease marked by the stretching and thinning of the heart muscle and impaired left ventricular contractile function. While most patients do not develop significant cardiac diseases from myocarditis, disparate immune responses can affect pathological outcomes, including DCM progression. These altered immune responses, which may be caused by genetic variance, can prolong cytotoxicity, induce direct cleavage of host protein, or encourage atypical wound healing responses that result in tissue scarring and impaired mechanical and electrical heart function. However, it is unclear which alterations within host immune profiles are crucial to dictating the outcomes of myocarditis. Coxsackievirus B3 (CVB3) is a well-studied virus that has been identified as a causal agent of myocarditis in various models, along with other viruses such as adenovirus, parvovirus B19, and SARS-CoV-2. This paper takes CVB3 as a pathogenic example to review the recent advances in understanding virus-induced immune responses and differential gene expression that regulates iron, lipid, and glucose metabolic remodeling, the severity of cardiac tissue damage, and the development of DCM and heart failure.

Global, regional, and national burdens of myocarditis, 1990-2019: systematic analysis from GBD 2019 : GBD for myocarditis

OBJECTIVES

Myocarditis, a health-threatening heart disease, is attracting increasing attention. This systematic study was conducted to study the prevalence of disease through the trends of incidence, mortality, disability-adjusted life years (DALYs) over the last 30 years, which would be helpful for the policymakers to better the choices for reasonable decisions.

METHODS

The global, regional, and national burdens of myocarditis from 1990-2019 were analyzed by using the 2019 Global Burden of Disease (GBD) database. This study on myocarditis produced new findings according to age, sex, and Social-Demographic Index (SDI) by investigating DALYs, age-standardized incidence rate (ASIR), age-standardized death rate (ASDR), and corresponding estimated annual percentage change (EAPC).

RESULTS

The number of myocarditis incidence increased by 62.19%, from 780,410 cases in 1990 to 1,265,770 cases in 2019. The ASIR decreased by 4.42% (95%CI, from -0.26% to -0.21%) over the past 30 years. The number of deaths from myocarditis increased by 65.40% from 19,618 in 1990 to 324,490 in 2019, but the ASDR was relatively stable over the investigated period. ASDR increased in low-middle SDI regions (EAPC=0.48; 95%CI, 0.24 to 0.72) and decreased in low SDI regions (EAPC=-0.97; 95%CI, from -1.05 to -0.89). The age-standardized DALY rate decreased by 1.19% (95%CI, from -1.33% to -1.04%) per year.

CONCLUSIONS

Globally, the ASIR and DALY for myocarditis decreased and the ASDR was stable over the past 30 years. The risk of incidences and death cases increased with age. Measures should be taken to control the risk of myocarditis in high-burden regions. Medical supplies should be improved in the high-middle SDI regions and middle SDI regions to reduce the deaths from myocarditis in these regions.

Current status of hand-foot-and-mouth disease

Hand-foot-and-mouth disease (HFMD) is a viral illness commonly seen in young children under 5 years of age, characterized by typical manifestations such as oral herpes and rashes on the hands and feet. These symptoms typically resolve spontaneously within a few days without complications. Over the past two decades, our understanding of HFMD has greatly improved and it has received significant attention. A variety of research studies, including epidemiological, animal, and in vitro studies, suggest that the disease may be associated with potentially fatal neurological complications. These findings reveal clinical, epidemiological, pathological, and etiological characteristics that are quite different from initial understandings of the illness. It is important to note that HFMD has been linked to severe cardiopulmonary complications, as well as severe neurological sequelae that can be observed during follow-up. At present, there is no specific pharmaceutical intervention for HFMD. An inactivated Enterovirus A71 (EV-A71) vaccine that has been approved by the China Food and Drug Administration (CFDA) has been shown to provide a high level of protection against EV-A71-related HFMD. However, the simultaneous circulation of multiple pathogens and the evolution of the molecular epidemiology of infectious agents make interventions based solely on a single agent comparatively inadequate. Enteroviruses are highly contagious and have a predilection for the nervous system, particularly in child populations, which contributes to the ongoing outbreak. Given the substantial impact of HFMD around the world, this Review synthesizes the current knowledge of the virology, epidemiology, pathogenesis, therapy, sequelae, and vaccine development of HFMD to improve clinical practices and public health efforts.

Atherosclerosis, Cardiovascular Disorders and COVID-19: Comorbid Pathogenesis

The article describes how atherosclerosis and coronavirus disease 19 (COVID-19) may affect each other. The features of this comorbid pathogenesis at various levels (vascular, cellular and molecular) are considered. A bidirectional influence of these conditions is described: the presence of cardiovascular diseases affects different individuals' susceptibility to viral infection. In turn, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can have a negative effect on the endothelium and cardiomyocytes, causing blood clotting, secretion of pro-inflammatory cytokines, and thus exacerbating the development of atherosclerosis. In addition to the established entry into cells via angiotensin-converting enzyme 2 (ACE2), other mechanisms of SARS-CoV-2 entry are currently under investigation, for example, through CD147. Pathogenesis of comorbidity can be determined by the influence of the virus on various links which are meaningful for atherogenesis: generation of oxidized forms of low-density lipoproteins (LDL), launch of a cytokine storm, damage to the endothelial glycocalyx, and mitochondrial injury. The transformation of a stable plaque into an unstable one plays an important role in the pathogenesis of atherosclerosis complications and can be triggered by COVID-19. The impact of SARS-CoV-2 on large vessels such as the aorta is more complex than previously thought considering its impact on vasa vasorum. Current information on the mutual influence of the medicines used in the treatment of atherosclerosis and acute COVID-19 is briefly summarized.

Vaccines against Group B Coxsackieviruses and Their Importance

The group B coxsackieviruses (CVBs) exist in six serotypes (CVB1 to CVB6). Disease associations have been reported for most serotypes, and multiple serotypes can cause similar diseases. For example, CVB1, CVB3, and CVB5 are generally implicated in the causation of myocarditis, whereas CVB1 and CVB4 could accelerate the development of type 1 diabetes (T1D). Yet, no vaccines against these viruses are currently available. In this review, we have analyzed the attributes of experimentally tested vaccines and discussed their merits and demerits or limitations, as well as their impact in preventing infections, most importantly myocarditis and T1D.

Mitochondria Dysfunction at the Heart of Viral Myocarditis: Mechanistic Insights and Therapeutic Implications

The myocardium/heart is the most mitochondria-rich tissue in the human body with mitochondria comprising approximately 30% of total cardiomyocyte volume. As the resident "powerhouse" of cells, mitochondria help to fuel the high energy demands of a continuously beating myocardium. It is no surprise that mitochondrial dysfunction underscores the pathogenesis of many cardiovascular ailments, including those of viral origin such as virus-induced myocarditis. Enteroviruses have been especially linked to injuries of the myocardium and its sequelae dilated cardiomyopathy for which no effective therapies currently exist. Intriguingly, recent mechanistic insights have demonstrated viral infections to directly damage mitochondria, impair the mitochondrial quality control processes of the cell, such as disrupting mitochondrial antiviral innate immune signaling, and promoting mitochondrial-dependent pathological inflammation of the infected myocardium. In this review, we briefly highlight recent insights on the virus-mitochondria crosstalk and discuss the therapeutic implications of targeting mitochondria to preserve heart function and ultimately combat viral myocarditis.

Cardiovascular manifestations of monkeypox virus outbreak: An overview of the reported cases

BACKGROUND

Monkeypox (Mpox) is a zoonotic DNA virus related to the orthopoxvirus family that causes also smallpox infection.

OBJECTIVES

In this paper, we aimed to study the cardiovascular manifestations of Mpox.

METHOD

A literature databases search was conducted on 20th October 2022 and limited to 2022 (the new outbreak) to collect all the relevant papers that discussed cardiovascular manifestations in Mpox.

RESULTS

The literature included 6 cases of myocarditis, one case of pericarditis, one case of myopericarditis and one case of atrial fibrillation. Of total 6 cases with completed data, ECG results and troponin levels were abnormal in 5 cases while only three cases had abnormal ECHO and CMR results. In the four cases who undergone chest X-rays, only one patient had non-specific retro-cardiac opacities. All patients (9 cases) recovered well from their cardiovascular manifestations with no deaths and only 3 of them required ICU admission.

CONCLUSION

With the limited reported cases, we recommend performing cardiovascular examinations -in particular ECG and troponin levels- in order to exclude cardiovascular insult in patients with suspected Mpox -cardiovascular involvement. However, in our series the infection was mild in most patients with no mortality.

Development of dilated cardiomyopathy with a long latent period followed by viral fulminant myocarditis: A case report

BACKGROUND

The clinical course of acute myocarditis ranges from the occurrence of a few symptoms to the development of fatal fulminant myocarditis. Specifically, fulminant myocarditis causes clinical deterioration very rapidly and aggressively. The long-term prognosis of myocarditis is varied, and it fully recovers without leaving any special complications. However, even after recovery, heart failure may occur and eventually progress to dilated cardiomyopathy (DCM), which causes serious left ventricular dysfunction. In the case of follow-up observation, no clear guidelines have been established.

CASE SUMMARY

We report the case of a 21-year-old woman who presented with dyspnea. She became hemodynamically unstable and showed sustained fatal arrhythmias with decreased heart function. She was clinically diagnosed with fulminant myocarditis based on her echocardiogram and cardiac magnetic resonance results. After 2 d, she was readmitted to the emergency department under cardiopulmonary resuscitation and received mechanical ventilation and extracorporeal membrane oxygenation. An implantable cardioverter defibrillator was inserted for secondary prevention. She recovered and was discharged. Prior to being hospitalized for sudden cardiac function decline and arrhythmia, she had been well for 7 years without any complications. She was finally diagnosed with dilated cardiomyopathy.

CONCLUSION

DCM may develop unexpectedly in patients who have been cured of acute fulminant myocarditis and have been stable with a long period of remission. Therefore, they should be carefully and regularly observed clinically throughout long-term follow-up.

Effect of Astragalus injection on inflammatory mediators in patients with viral myocarditis: A systematic review and meta-analysis

BACKGROUND

To explore the therapeutic effect and mechanism of Astragalus injection on viral myocarditis, we conducted a systematic review and meta-analysis to identify the influence of Astragalus injection on inflammatory mediators and overall efficiency in patients undergoing viral myocarditis.

METHODS

EMBASE, Cochrane Library, PubMed, Chinese Biomedical Literature, Chinese National Knowledge Infrastructure (CNKI), and Wanfang databases were searched to screen randomized controlled trials (RCTs) published before July 3, 2022. The quality of participating studies was assessed by the Cochrane Collaboration Risk of Bias tool. The calculation of qualitative data used a risk ratio (RR) with a 95% confidence interval (95% CI), and quantitative data had standardized mean differences (SMDs) with a 95% CI. The heterogeneity among trials was quantified with Cochran's Q test and the I² statistic. Confounding factors were estimated by sensitivity analysis, meta-regression, and subgroup analysis. The publication bias of participating articles was evaluated by funnel plot and Egger's test. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) system was recommended for assessing the strength of evidence.

RESULTS

Nineteen available studies were included in our present meta-analysis, all of which were conducted in China. The outcomes expose that Astragalus injection dramatically decreased the levels of pro-inflammatory TNF-α (SMD=-2.271, 95% CI=-2.802 to -1.739, p<0.001, I²=90.6%), IL-6 (SMD=-1.501, 95% CI=-1.872 to -1.130, p<0.001, I²=83.2%), IL-17 (SMD=-3.194, 95% CI=-4.569 to -1.818, p<0.001, I²=88.9%), 1L-8 (SMD=-6.133, 95% CI=-9.938 to -2.328, p = 0.002, I²=97%), 1L-1 (SMD=-1.814, 95% CI=-2.557 to -1.070, p<0.001, I²=92.1%), CRP (SMD=-2.020, 95% CI=-3.107 to -0.932, p<0.001, I²=92.7%), and IFN-γ (SMD=-1.512, 95% CI=-2.771 to -0.253, p = 0.019, I²=92%) and increased the total effective rate of treatment (RR=1.225, 95% CI=1.17 to 1.29, p<0.001, I²=0.0%) in patients with viral myocarditis.

CONCLUSION

Astragalus injection can play a therapeutic role in patients with viral myocarditis through immunomodulatory effects. Outcomes were treated with caution due to significant heterogeneity among studies. Large-scale RCTs should be performed to support these conclusions.

Myocarditis Attributable to Monkeypox Virus Infection in 2 Patients, United States, 2022

We report 2 immunocompetent and otherwise healthy adults in the United States who had monkeypox and required hospitalization for viral myocarditis. Both patients were unvaccinated against orthopoxviruses. They had shortness of breath or chest pain and elevated cardiac biomarkers. No immediate complications were observed. They were discharged home after symptoms resolved.

Stem cell factor/mast cell/CCL2/monocyte/macrophage axis promotes Coxsackievirus B3 myocarditis and cardiac fibrosis by increasing Ly6Chigh monocyte influx and fibrogenic mediators production

Mast cells (MCs), central players in allergy and parasitic infections, play key roles in inflammation and fibrosis. Here, the impact of MCs on the progression of Coxsackievirus B3 (CVB3)-induced viral myocarditis (VMC) and fibrosis was investigated using MC-deficient Kit^W-sh mice. Viral titres, cellular infiltrates and heart pathologies were evaluated and compared with wild-type (WT) mice during acute CVB3 infection of C57BL/6 mice. CVB3 infection induced an increased accumulation and degranulation of MCs in the hearts of mice during acute infection. MC-deficient Kit^W-sh mice had slightly higher viral titres, decreased VMC and cardiac fibrosis and improved cardiac dysfunction compared to WT mice via decreasing cardiac influx of Ly6C^high monocytes/macrophages (Mo/Mφ). While bone marrow-derived MC reconstitution decreased viral titre and worsened improved survival and VMC severity in Wsh mice. MC-fibroblasts co-culture revealed a cardiac MC-fibroblasts crosstalk during early infection: fibroblasts trigger MC degranulation and secretion of CCL2 and tumour necrosis factor alpha (TNF-α) via producing early stem cell factor (SCF); while MCs-fibrogenic mediators (TNF-α) stimulate fibroblasts to increase CCL2, α-smooth muscle actin (SMA), collagen and transforming growth factor beta（TGFβ) expression, thus aggravating cardiac fibrosis. MCs and fibroblast-derived CCL2s are both essential for cardiac Ly6C^high Mo/Mφ influx. Administration of recombinant mouse SCF to CVB3-infected mice aggravates VMC via accelerating MCs accumulation and cardiac influx of Ly6C^hi Mo/Mφ. Collectively, our data highlight an early MC-fibroblast crosstalk and SCF/MC/CCL2/Mo/Mφ axis as important mechanisms required for triggering VMC and myocardial fibrosis. This finding indicates critical roles of MCs in initiating and modulating cardiac innate response to CVB3 and has an implication in developing new and more effective treatments for VMC.

IL-37 alleviates Coxsackievirus B3-induced viral myocarditis via inhibiting NLRP3 inflammasome-mediated pyroptosis

Our study aims to verify the potential effects and underlying mechanisms of IL-37 in Coxsackievirus B3 (CVB3)-induced viral myocarditis (VMC). VMC model was established by intraperitoneal injection of CVB3 into 6-week-old male balb-c mice on day 0. Each mouse of the IL-37-control group and IL-37-VMC CVB3 groups was intraperitoneally injected with IL-37 on day 4 and day 7. The cardiac function was evaluated by transthoracic echocardiography including LVEF, LVFE, IVSs and IVSd. Myocardial injury was measured by Elisa for serum cTnI. The inflammation infiltration and fibrosis were evaluated by hematoxylin and eosin (HE) staining and Masson staining. The expression levels of NLRP3 inflammasome components in pyroptosis were determined by western blot, Elisa, and immunofluorescent analysis. We also detected the expression of IL-37-IL-1R8 in PBMCs by immunofluorescence after injection with CVB3 and IL-37. Compared with the VMC group, mice received CVB3 and IL-37 have improved cardiac function, reduced inflammation infiltration and fibrosis, and with lower expression of cTnI, IL-1β, IL-18 and NLRP3 inflammasome component. IL-37 weakened the upregulation of GSDMD and phosphorylation of NF-κB p65 induced by CVB3. Exogenous addition of IL-37 with CVB3 further increases the production of IL-37-IL-1R8 -IL-18RA complex in vitro. Our findings indicate that IL-37 alleviates CVB3-induced VMC, which may be produced by inhibiting NLRP3 inflammasome-mediated pyroptosis, NF-κB signaling pathway, and IL-37-IL-1R8 -IL-18RA complex.

Spatiotemporal transcriptomics reveals pathogenesis of viral myocarditis

A significant fraction of sudden death in children and young adults is due to viral myocarditis, an inflammatory disease of the heart. In this study, by using integrated single-cell and spatial transcriptomics, we created a high-resolution, spatially resolved transcriptome map of reovirus-induced myocarditis in neonatal mouse hearts. We assayed hearts collected at three timepoints after infection and studied the temporal, spatial and cellular heterogeneity of host–virus interactions. We further assayed the intestine, the primary site of reovirus infection, to establish a full chronology of molecular events that ultimately lead to myocarditis. We found that inflamed endothelial cells recruit cytotoxic T cells and undergo pyroptosis in the myocarditic tissue. Analyses of spatially restricted gene expression in myocarditic regions and the border zone identified immune-mediated cell-type-specific injury and stress responses. Overall, we observed a complex network of cellular phenotypes and spatially restricted cell–cell interactions associated with reovirus-induced myocarditis in neonatal mice.

PhIP-Seq Reveals Autoantibodies for Ubiquitously Expressed Antigens in Viral Myocarditis

Simple Summary

Myocarditis is the inflammation of the heart muscle, and viral infections are a common cause of this disease. Myocarditis in some patients can progress to dilated cardiomyopathy (DCM). The mouse model of coxsackievirus B3 (CVB3) is commonly used to understand this disease progression in DCM patients. In this paper, we have attempted to analyze antibodies for heart antigens that could be produced as a result of heart damage in animals infected with CVB3 using a technique called Phage ImmunoPrecipitation Sequencing (PhIP-Seq). The analyses led us to identify antibodies for several proteins that were not previously reported that may have relevance to human disease.

Abstract

Enteroviruses such as group B coxsackieviruses (CVB) are commonly suspected as causes of myocarditis that can lead to dilated cardiomyopathy (DCM), and the mouse model of CVB3 myocarditis is routinely used to understand DCM pathogenesis. Mechanistically, autoimmunity is suspected due to the presence of autoantibodies for select antigens. However, their role continues to be enigmatic, which also raises the question of whether the breadth of autoantibodies is sufficiently characterized. Here, we attempted to comprehensively analyze the autoantibody repertoire using Phage ImmunoPrecipitation Sequencing (PhIP-Seq), a versatile and high-throughput platform, in the mouse model of CVB3 myocarditis. First, PhIP-Seq analysis using the VirScan library revealed antibody reactivity only to CVB3 in the infected group but not in controls, thus validating the technique in this model. Second, using the mouse peptide library, we detected autoantibodies to 32 peptides from 25 proteins in infected animals that are ubiquitously expressed and have not been previously reported. Third, by using ELISA as a secondary assay, we confirmed antibody reactivity in sera from CVB3-infected animals to cytochrome c oxidase assembly factor 4 homolog (COA4) and phosphoinositide-3-kinase adaptor protein 1 (PIK3AP1), indicating the specificity of antibody detection by PhIP-Seq technology. Fourth, we noted similar antibody reactivity patterns in CVB3 and CVB4 infections, suggesting that the COA4- and PIK3AP1-reactive antibodies could be common to multiple CVB infections. The specificity of the autoantibodies was affirmed with influenza-infected animals that showed no reactivity to any of the antigens tested. Taken together, our data suggest that the autoantibodies identified by PhIP-Seq may have relevance to CVB pathogenesis, with a possibility that similar reactivity could be expected in human DCM patients.

Establishment of a novel myocarditis mouse model based on cyclosporine A

BACKGROUND

Myocarditis is a myocardial injury that can easily cause adolescent death. Traditional research models of animal invasion with viral components, lipopolysaccharide (LPS) or porcine myocardial myosin, among others, have the shortcomings of potential biological safety hazards and high animal mortality.

OBJECTIVE

To explore the construction of a novel myocarditis model with cyclosporine A and the potential genes and pathways associated with it.

METHODS

BALB/c mice were used in this study, and cyclosporin A and LPS were injected into the peritoneal cavity of mice. The successful establishment of the model was assessed by detecting serum myocardial injury markers and inflammatory factors levels, HE, IHC staining, and RT-qPCR methods. Key genes were obtained using the GSE35182 dataset from the GEO database and validated with the RT-qPCR method.

RESULTS

We found that a large number of inflammatory cells infiltrated the myocardium of mice in each group of Cyclosporin A constructed model, while the expression of inflammatory factor indicators was increased, and this model has the characteristics of high degree of local inflammation in myocardial tissue, low mortality, and safe and non-toxic treatment. Using GSE35182 data, we selected 18 Hub genes and validated Hub genes in myocardial tissue with RT-qPCR and found that multiple signaling pathways such as Toll-likereceptor signaling pathway(TLRs), Rap1 signal pathway(Rap1), and Chemokine signaling pathway may be involved in the development of myocarditis.

CONCLUSION

Cyclosporin A can construct a new myocarditis model, and TLRs, Chemokines and Rap1 signaling pathways may be the core pathways of myocarditis.