Myocarditis: causes, mechanisms, and evolving therapies.

INTRODUCTION: Myocarditis is a severe lymphocyte-mediated inflammatory disorder of the heart, mostly caused by viruses and immune checkpoint inhibitors (ICIs). Recently, myocarditis as a rare adverse event of mRNA vaccines for SARS-CoV-2 has caused global attention. The clinical consequences of myocarditis can be very severe, but specific treatment options are lacking or not yet clinically proven. AREAS COVERED: This paper offers a brief overview of the biology of viruses that frequently cause myocarditis, focusing on mechanisms important for viral entry and replication following host infection. Current and new potential therapeutic targets/strategies especially for viral myocarditis are reviewed systematically. In particular, the immune system in myocarditis is dissected with respect to infective viral and non-infective, ICI-induced myocarditis. EXPERT OPINION: Vaccination is an excellent emerging preventative strategy for viral myocarditis, but most vaccines still require further development. Anti-viral treatments that inhibit viral replication need to be considered following viral infection in host myocardium, as lower viral load reduces inflammation severity. Understanding how the immune system continues to damage the heart even after viral clearance will define novel therapeutic targets/strategies. We propose that viral myocarditis can be best treated using a combination of antiviral agents and immunotherapies that control cytotoxic T cell activity.

[Massive pancarditis-autopsy report]. / Massive Pankarditis ­ ein Autopsiebericht.

We report on a 69-year-old man suffering from chronic progressive oligoarthritis (localized in metacarpal and knee joints), which clinically was interpreted as steroid-sensitive seronegative chronic arthritis. The patient died from sudden death at the emergency department after a 4-week history of increasing cough and dyspnea (meanwhile obtaining negative testing results for SARS-CoV-2). During the autopsy, we found massive pancarditis affecting all cardiac compartments, in particular exhibiting constrictive pericarditis, myocarditis, and multivalvular endocarditis. Microscopically, interstitial myocarditis could be observed. Performing extensive molecular analyses, we detected Tropheryma whipplei in the tissue specimens of the heart, but not in various duodenal tissue probes or in the synovial membrane. Taken together, in the present case the cause of death was acute cardiac failure due to multivalvular pancarditis due to T. whipplei. Besides from classical symptoms and morphological signs, Whipple's disease may present with various features. Regarding the differential diagnosis of a chronic multisystem disorder with aspects of hitherto unknown arthralgia, Whipple's disease should be considered.

Recurrent Myocarditis Treated with Intravenous Immune Globulin and Steroids.

BACKGROUND Myocarditis is an inflammatory process that can present as acute or chronic with either focal or diffuse involvement of the myocardium. Its incidence is approximately 1.5 million cases per year worldwide. In the United States, viral infection is the most common cause of myocarditis. Most of the reported cases are singular and self-limiting in nature. We present the case of severe recurrent myocarditis in a young adult who was transferred to the Intensive Care Unit. CASE REPORT An 18-year-old man presented with chest pressure and troponin I 33 ng/mL. He had presented to another hospital with similar symptoms 3 months prior and was diagnosed with myocarditis that had resolved with colchicine. As part of his workup during this admission, coronary angiogram was normal and biopsy obtained without evidence of an inflammatory process; however, cardiac magnetic resonance imaging (MRI) was consistent with myocarditis and Coxsackie B titers indicated prior infection, leading to a diagnosis of clinically suspected recurrent viral myocarditis. He was treated with intravenous immunoglobulin (IV Ig) and a steroid taper, with rapid improvement in symptoms over the ensuing weeks without evidence of further recurrence or sequelae. CONCLUSIONS We present a case of recurrent Coxsackie B myocarditis based on presentation and imaging. Myocarditis is an important diagnosis to consider when a young, healthy individual presents with chest pain mimicking acute coronary syndrome, especially during the COVID pandemic. If there is evidence of myocarditis on MRI or endomyocardial biopsy, immunosuppressive therapy should be considered in patients with recurrent and severe presentations.

Computational identification of Shenshao Ningxin Yin as an effective treatment for novel coronavirus infection (COVID-19) with myocarditis.

BACKGROUND: The newly identified betacoronavirus SARS-CoV-2 is the causative pathogen of the 2019 coronavirus disease (COVID-19), which has killed more than 4.5 million people. SARS-CoV-2 causes severe respiratory distress syndrome by targeting the lungs and also induces myocardial damage. Shenshao Ningxin Yin (SNY) has been used for more than 700 years to treat influenza. Previous randomized controlled trials (RCTs) have demonstrated that SNY can improve the clinical symptoms of viral myocarditis, reverse arrhythmia, and reduce the level of myocardial damage markers. METHODS: This work uses a rational computational strategy to identify existing drug molecules that target host pathways for the treatment of COVID-19 with myocarditis. Disease and drug targets were input into the STRING database to construct proteinɃprotein interaction networks. The Metascape database was used for GO and KEGG enrichment analysis. RESULTS: SNY signaling modulated the pathways of coronavirus disease, including COVID-19, Ras signaling, viral myocarditis, and TNF signaling pathways. Tumor necrosis factor (TNF), cellular tumor antigen p53 (TP53), mitogen-activated protein kinase 1 (MAPK1), and the signal transducer and activator of transcription 3 (STAT3) were the pivotal targets of SNY. The components of SNY bound well with the pivotal targets, indicating there were potential biological activities. CONCLUSION: Our findings reveal the pharmacological role and molecular mechanism of SNY for the treatment of COVID-19 with myocarditis. We also, for the first time, demonstrate that SNY displays multi-component, multi-target, and multi-pathway characteristics with a complex mechanism of action.

Comparison and Analysis on the Existing Single-Herbal Strategies against Viral Myocarditis.

Purpose: Herbal medicine is one of crucial symbols of Chinese national medicine. Investigation on molecular responses of different herbal strategies against viral myocarditis is immeasurably conducive to targeting drug development in the current international absence of miracle treatment. Methods: Literature retrieval platforms were applied in the collection of existing empirical evidences for viral myocarditis-related single-herbal strategies. SwissTargetPrediction, Metascape, and Discovery Studio coordinating with multidatabases investigated underlying target genes, interactive proteins, and docking molecules in turn. Results: Six single-herbal medicines consisting of Huangqi (Hedysarum Multijugum Maxim), Yuganzi (Phyllanthi Fructus), Kushen (Sophorae Flavescentis Radix), Jianghuang (Curcumaelongae Rhizoma), Chaihu (Radix Bupleuri), and Jixueteng (Spatholobus Suberectus Dunn) meet the requirement. There were 11 overlapped and 73 unique natural components detected in these herbs. SLC6A2, SLC6A4, NOS2, PPARA, PPARG, ACHE, CYP2C19, CYP51A1, and CHRM2 were equally targeted by six herbs and identified as viral myocarditis-associated symbols. MCODE algorithm exposed the hub role of SRC and EGFR in strategies without Jianghuang. Subsequently, we learned intermolecular interactions of herbal components and their targeting heart-tissue-specific CHRM2, FABP3, TNNC1, TNNI3, TNNT2, and SCN5A and cardiac-myocytes-specific IL6, MMP1, and PLAT coupled with viral myocarditis. Ten interactive characteristics such as π-alkyl and van der Waals were modeled in which ARG111, LYS253, ILE114, and VAL11 on cardiac troponin (TNNC1-TNNI3-TNNT2) and ARG208, ASN106, and ALA258 on MMP1 fulfilled potential communicating anchor with ellagic acid, 5α, 9α-dihydroxymatrine, and leachianone g via hydrogen bond and hydrophobic interaction, respectively. Conclusions: The comprehensive outcomes uncover differences and linkages between six herbs against viral myocarditis through component and target analysis, fostering development of drugs.

The Spontaneous Course of Human Herpesvirus 6 DNA-Associated Myocarditis and the Effect of Immunosuppressive Intervention.

INTRODUCTION: This study investigated the spontaneous clinical course of patients with endomyocardial biopsy (EMB)-proven lymphocytic myocarditis and cardiac human herpesvirus 6 (HHV6) DNA presence, and the effectiveness of steroid-based intervention in HHV6-positive patients. RESULTS: 756 heart failure (HF) patients underwent an EMB procedure to determine the underlying cause of unexplained HF. Low levels of HHV6 DNA, detectable by nested PCR only, were found in 10.4% of the cases (n = 79) of which 62% (n = 49) showed myocardial inflammation. The spontaneous course of patients with EMB-proven HHV6 DNA-associated lymphocytic myocarditis (n = 26) showed significant improvements in the left ventricular ejection fraction (LVEF) and clinical symptoms, respectively, in 15/26 (60%) patients, 3-12 months after disease onset. EMB mRNA expression of components of the NLRP3 inflammasome pathway and protein analysis of cardiac remodeling markers, analyzed by real-time PCR and MALDI mass spectrometry, respectively, did not differ between HHV6-positive and -negative patients. In another cohort of patients with ongoing symptoms related to lymphocytic myocarditis associated with cardiac levels of HHV6-DNA copy numbers <500 copies/µg cardiac DNA, quantified by real-time PCR, the efficacy and safety of steroid-based immunosuppression for six months was investigated. Steroid-based immunosuppression improved the LVEF (≥5%) in 8/10 patients and reduced cardiac inflammation in 7/10 patients, without an increase in cardiac HHV6 DNA levels in follow-up EMBs. CONCLUSION: Low HHV6 DNA levels are frequently detected in the myocardium, independent of inflammation. In patients with lymphocytic myocarditis with low levels of HHV6 DNA, the spontaneous clinical improvement is nearby 60%. In selected symptomatic patients with cardiac HHV6 DNA copy numbers less than 500 copies/µg cardiac DNA and without signs of an active systemic HHV6 infection, steroid-based therapy was found to be effective and safe. This finding needs to be further confirmed in large, randomized trials.

The mechanism underlying extrapulmonary complications of the coronavirus disease 2019 and its therapeutic implication.

The coronavirus disease 2019 (COVID-19) is a highly transmissible disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that poses a major threat to global public health. Although COVID-19 primarily affects the respiratory system, causing severe pneumonia and acute respiratory distress syndrome in severe cases, it can also result in multiple extrapulmonary complications. The pathogenesis of extrapulmonary damage in patients with COVID-19 is probably multifactorial, involving both the direct effects of SARS-CoV-2 and the indirect mechanisms associated with the host inflammatory response. Recognition of features and pathogenesis of extrapulmonary complications has clinical implications for identifying disease progression and designing therapeutic strategies. This review provides an overview of the extrapulmonary complications of COVID-19 from immunological and pathophysiologic perspectives and focuses on the pathogenesis and potential therapeutic targets for the management of COVID-19.

Proposed Pathogenesis, Characteristics, and Management of COVID-19 mRNA Vaccine-Related Myopericarditis.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the novel coronavirus causing coronavirus disease 2019 (COVID-19), has affected human lives across the globe. On 11 December 2020, the US FDA granted an emergency use authorization for the first COVID-19 vaccine, and vaccines are now widely available. Undoubtedly, the emergence of these vaccines has led to substantial relief, helping alleviate the fear and anxiety around the COVID-19 illness for both the general public and clinicians. However, recent cases of vaccine complications, including myopericarditis, have been reported after administration of COVID-19 vaccines. This article discusses the cases, possible pathogenesis of myopericarditis, and treatment of the condition. Most cases were mild and should not yet change vaccine policies, although prospective studies are needed to better assess the risk-benefit ratios in different groups.

Taming the Storm in the Heart: Exploring Different Therapeutic Choices Against Myocardial Inflammation in COVID-19.

Mechanism of cardiac injury in COVID-19 is a serious problem and plays critical role in mediating the severity of the disease. However, the mechanistic insights of the induction of the inflammatory signal leading to cardiac injury was poorly understood. However, few recent studies have indicated the involvement of Toll-Like Receptors (TLRs) as the major 'culprit' behind eliciting the initial signal of 'cytokine storm'. As a result, TLRs are now considered as the therapeutic targets to develop efficacious therapeutics. Herein, we present an overall summary on the mechanistic insight of cardiac injury in COVID-19 patients and the therapeutic promises of TLR-targeted therapies.

HMG-CoA Reductase Inhibitor, Simvastatin Is Effective in Decreasing Degree of Myocarditis by Inhibiting Metalloproteinases Activation.

BACKGROUND: Acute myocarditis often progresses to heart failure because there is no effective, etiology-targeted therapy of this disease. Simvastatin has been shown to be cardioprotective by decreasing matrix metalloproteinases' (MMPs) activity. The study was designed to determine whether simvastatin inhibits MMPs activity, decreases the severity of inflammation and contractile dysfunction of the heart in experimental autoimmune myocarditis (EAM). METHODS: Simvastatin (3 or 30 mg/kg/day) was given to experimental rats with EAM by gastric gavage for 21 days. Then transthoracic echocardiography was performed, MMPs activity and troponin I level were determined and tissue samples were assessed under a light and transmission electron microscope. RESULTS: Hearts treated with simvastatin did not show left ventricular enlargement. As a result of EAM, there was an enhanced activation of MMP-9, which was significantly reduced in the high-dose simvastatin group compared to the low-dose group. It was accompanied by prevention of myofilaments degradation and reduction of severity of inflammation. CONCLUSIONS: The cardioprotective effects of simvastatin in the acute phase of EAM are, at least in part, due to its ability to decrease MMP-9 activity and subsequent decline in myofilaments degradation and suppression of inflammation. These effects were achieved in doses equivalent to therapeutic doses in humans.

Six Month Follow-up of Patients With Multi-System Inflammatory Syndrome in Children.

BACKGROUND AND OBJECTIVES: Myocardial dysfunction and coronary abnormalities are prominent features of multisystem inflammatory syndrome in children (MIS-C). In this study we aim to evaluate the early and midterm outcomes of MIS-C. METHODS: This is a longitudinal 6-month cohort study of all children admitted and treated for MIS-C from April 17 to June 20, 2020. Patients were followed ∼2 weeks, 8 weeks, and 6 months postadmission, with those with coronary aneurysms evaluated more frequently. RESULTS: Acutely, 31 (62%) patients required intensive care with vasoactive support, 26 (52%) had left ventricular (LV) systolic dysfunction, 16 (32%) had LV diastolic dysfunction, 8 (16%) had coronary aneurysms (z score ≥2.5), and 4 (8%) had coronary dilation (z score <2.5). A total of 48 patients (96%) received immunomodulatory treatment. At 2 weeks, there was persistent mild LV systolic dysfunction in 1 patient, coronary aneurysms in 2, and dilated coronary artery in 1. By 8 weeks through 6 months, all patients returned to functional baseline with normal LV systolic function and resolution of coronary abnormalities. Cardiac MRI performed during recovery in select patients revealed no myocardial edema or fibrosis. Some patients demonstrated persistent diastolic dysfunction at 2 weeks (5, 11%), 8 weeks (4, 9%), and 6 months (1, 4%). CONCLUSIONS: Children with MIS-C treated with immunomodulators have favorable early outcomes with no mortality, normalization of LV systolic function, recovery of coronary abnormalities, and no inflammation or scarring on cardiac MRI. Persistence of diastolic dysfunction is of uncertain significance and indicates need for larger studies to improve understanding of MIS-C. These findings may help guide clinical management, outpatient monitoring, and considerations for sports clearance.

A Case Report for Myopericarditis after BNT162b2 COVID-19 mRNA Vaccination in a Korean Young Male.

Mass vaccination with the Pfizer-BioNTech coronavirus disease 2019 (COVID-19) vaccine (BNT162b2) in Korea has resulted in many reported adverse effects. These side effects are the object of much scrutiny in the medical community. We report the case of a 29-year-old male who was diagnosed with myopericarditis after his second dose of Pfizer-BioNTech COVID-19 vaccine. This patient is the second recognized case of Pfizer-BioNTech COVID-19 vaccine induced myopericarditis in Korea and the first to have recovered from it. He originally presented with chest discomfort and exertional chest pain. Lab tests revealed elevated cardiac marker levels and echocardiographic findings displayed minimal pericardial effusion, prompting diagnosis as myopericarditis. We decided on two weeks of outpatient treatment with non-steroidal anti-inflammatory drugs (NSAIDs) due to the patient's mild symptoms and his occupation in the military. When this proved insufficient, we shifted to combination therapy with low dose corticosteroids and NSAIDs. After two weeks of treatment, the patient's symptoms and pericardial effusion had improved, and he was recovered completely 37 days after the onset.

Immunosuppressive therapy in childhood-onset arrhythmogenic inflammatory cardiomyopathy.

We present, to our knowledge, the first case of immunosuppressive therapy (IST) application in a 12-year-old child with arrhythmogenic inflammatory cardiomyopathy resulting from the overlap between autoimmune myocarditis and primary arrhythmogenic cardiomyopathy. Indication to off-lable IST was compelling, because of recurrent drug-refractory ventricular arrhythmias (VAs). We show that IST was feasible, safe, and effective on multiple clinical endpoints, including symptoms, VA recurrences, and T-troponin release. Remarkably, all diagnostic and therapeutic strategies were worked out by a dedicated multidisciplinary team, including specialized pediatric immunologists.

Perimyocarditis following first dose of the mRNA-1273 SARS-CoV-2 (Moderna) vaccine in a healthy young male: a case report.

BACKGROUND: Half of U.S. adults have received at least one dose of the COVID-19 vaccines produced by either Pfizer, Moderna, or Johnson and Johnson, which represents a major milestone in the ongoing pandemic. Given the emergency use authorizations for these vaccines, their side effects and safety were assessed over a compressed time period. Hence, ongoing monitoring for vaccine-related adverse events is imperative for a full understanding and delineation of their safety profile. CASE PRESENTATION: An 22-year-old Caucasian male presented to our hospital center complaining of pleuritic chest pain. Six months prior he had a mild case of COVID-19, but was otherwise healthy. He had received his first dose of the Moderna vaccine three days prior to developing symptoms. Laboratory analysis revealed a markedly elevated troponin and multiple imaging modalities during his hospitalization found evidence of wall motion abnormalities consistent with a diagnosis of perimyocarditis. He was started on aspirin and colchicine with marked improvement of his symptoms prior to discharge. CONCLUSIONS: We present a case of perimyocarditis that was temporally related to COVID-19 mRNA vaccination in an young male with prior COVID-19 infection but otherwise healthy. Our case report highlights an albeit rare but important adverse event for clinicians to be aware of. It also suggests a possible mechanism for the development of myocardial injury in our patient.

Recent Experience: Corticosteroids as a First-line Therapy in Children With Multisystem Inflammatory Syndrome and COVID-19-related Myocardial Damage.

BACKGROUND: Cardiovascular complications with myocarditis in multisystem inflammatory syndrome in children (MIS-C) associated with severe acute respiratory syndrome coronavirus 2 infection have been reported, but the optimal therapeutic strategy remains unknown. METHODS: A retrospective cohort study included 19 patients with acute left ventricular systolic dysfunction associated with MIS-C, average years of age 13.2 ± 3.8, treated from April 2020 to April 2021. RESULTS: Treatment failure (TF) was observed in 8 patients (in the intravenous immunoglobulin [IVIG] group 7/10; in the corticosteroid [CS] group 1/9). The independent risk factor for TF was IVIG treatment (odds ratio [OR] 18.6, 95% confidence interval [CI] 1.6-222.93, P = 0.02). Patients initially treated with CS became afebrile during in-hospital day 1 (1.5, interquartile range [IQR] 1-2), while IVIG-treated patients became afebrile on in-hospital day 4 (IQR 2-4.25), after CS was added. The C-reactive protein (CRP) significantly declined in CS-treated patients on day 2 (P = 0.01), while in the IVIG group, CRP decreased significantly on the fourth day (P = 0.04). Sodium and albumin levels were higher on third in-hospital day in the CS group than in the IVIG group (P = 0.015, P = 0.03). A significant improvement and normalization of ejection fraction (EF) during the first 3 days was observed only in the CS group (P = 0.005). ICU stays were shorter in the CS group (4, IQR 2-5.5) than in the IVIG group (IVIG group 7, IQR 6-8.5) (P = 0.002). CONCLUSIONS: Among children with MIS-C with cardiovascular involvement, treatment with CS was associated with faster normalization of LV EF, fever, laboratory analysis, and shorter ICU than IVIG-treated patients.

COVID-19-associated myocarditis presenting as new-onset heart failure and atrial fibrillation.

A 58-year-old man presented to the emergency department with recent-onset palpitations and progressive exertional dyspnoea. ECG demonstrated new-onset atrial fibrillation. Transthoracic echocardiogram showed global impairment in left ventricular systolic function with left ventricular ejection fraction of 20%. Cardiac MRI (CMRI) demonstrated generalised severe myocarditis. A SARS-CoV-2 PCR was positive for SARS-CoV-2 RNA. As such, we diagnosed our patient with COVID-19-associated myocarditis based on CMRI appearances and positive SARS-CoV-2 swab. This case highlights that COVID-19-associated myocarditis can present as new atrial fibrillation and heart failure without the classic COVID-19-associated symptoms.