Immunopathogenesis and treatment of myocarditis: the United States Myocarditis Treatment Trial

Effect of Acute Immunosuppression on Left Ventricular Recovery and Mortality in Fulminant Viral Myocarditis: A Case Series and Review of Literature

Background

Fulminant viral myocarditis (FVM) is a rare cause of cardiogenic shock associated with high morbidity and mortality rates. An inappropriately activated immune system results in severe myocardial inflammation. Acute immunosuppressive therapy for FVM therefore gained in popularity and was described in numerous retrospective studies.

Methods

We conducted an extensive review of the literature and compared it with our single-centre retrospective review of all cases of FVM from 2009-2019 to evaluate the possible effect of acute immunosuppression with intravenous immunoglobulins and/or high dose corticosteroids in patients with FVM.

Results

We report on 17 patients with a mean age of 46 ± 15 years with a mean left ventricular ejection fraction (LVEF) of 15 ± 9% at admission. Fourteen (82%) of our patients had acute LVEF recovery to ≥ 45% after a mean time from immunosuppression of 74 ± 49 hours (3.1 days). Extracorporeal membrane oxygenation (ECMO) was required in 35% (6/17) of our patients for an average support of 126 ± 37 hours. Overall mortality was 12% (2/17). No patient needed a long-term left ventricular assist device or heart transplant. All surviving patients achieved complete long-term LVEF recovery.

Conclusions

Our cohort of 17 severely ill patients received acute immunosuppressive therapy and showed a rapid LVEF recovery, short duration of ECMO support, and low mortality rate. Our suggested scheme of investigation and treatment is presented. These results bring more cases of successfully treated FVM with immunosuppression and ECMO to the literature, which might stimulate further prospective trials or a registry.

Angiotensin II-C-C chemokine receptor2/5 axis-dependent monocyte/macrophage recruitment contributes to progression of experimental autoimmune myocarditis

Angiotensin II (ANG II) plays critical roles in modulation of circulatory homeostasis and activation of innate and adaptive immunity and has also been implicated in several mouse models of autoimmune disease. However, how ANG II regulates macrophages and is involved in development of experimental autoimmune myocarditis (EAM) remains unclear. Therefore, the present study aimed to address the above question and explore possible mechanisms. EAM was induced in BALB/c mice. ANG II was quantitated by ELISA and hematoxylin and eosin staining was employed to analyze pathological changes and macrophage infiltration. The chemotactic ability of ANG II was assessed by using a Transwell system. It was found that ANG II is up-regulated in serum and heart tissues of mice with EAM and that ANG II significantly drives monocyte/macrophage infiltration through the C-C chemokine receptor 2/5 (CCR2/5) axis. CCR2/5 antagonists and ANG II receptor inhibitor could all abrogate monocyte/macrophage infiltration and ameliorate development of EAM. Our results have firstly identified a novel function of ANG II: that it is a critical chemokine for monocyte/macrophage recruitment. Furthermore, our results indicate that ANG II is a potential candidate for treatment of inflammatory diseases.

Corticosteroids for viral myocarditis

BACKGROUND

Myocarditis is an uncommon heart disease. There is experimental evidence showing that autoimmune mechanisms follow viral infection, resulting in inflammation and necrosis in myocardium. However, the use of corticosteroids as immunosuppressives in this condition remains controversial.

OBJECTIVES

To assess the beneficial and harmful effects of treating viral myocarditis with corticosteroids.

SEARCH STRATEGY

Trials were identified by searching The Cochrane Heart Group Register (to April 2004), the Cochrane Library (Issue 4, 2003), and MEDLINE, EMBASE, BIOSIS for meeting abstracts, LILACS, and Chinese Biomedical CD Database from their date of inception to April 20, 2004. Four Chinese medical journals were handsearched. A total of 507 articles were found but none of them was eligible to be included in our review.

SELECTION CRITERIA

Randomised controlled trials of corticosteroids for viral myocarditis compared with no intervention, placebo, supportive therapy, antiviral agents therapy or conventional therapy, including trials of corticosteroids plus other treatment versus other treatment alone, irrespective of blinding, publication status, or language.

DATA COLLECTION AND ANALYSIS

Two reviewers extracted data independently. We asked authors of trials to provide information when diagnosis or methodology was unclear or data were incomplete. Results were presented as risk ratios (RR) and weighted mean differences (WMD), both with 95% confidence intervals (CI).

MAIN RESULTS

No randomised controlled trials of corticosteroids for viral myocarditis were found that met our inclusion criteria.

AUTHORS' CONCLUSIONS

There is no randomised evidence to support the use of corticosteroids for viral myocarditis. Further clinical trials are needed.

Immunosuppressive Treatment for Inflammatory Cardiomyopathy: Meta-Analysis of Randomized Controlled Trials

The use of immunosuppressive therapy for inflammatory cardiomyopathy is controversial. The aim of this review is to summarize the current empirical evidence for immunosuppressive treatment in inflammatory cardiomyopathy. We conducted a meta-analysis of all randomized controlled trials (RCTs) that compared immunosuppressive therapy with either placebo or conventional treatment in patients with inflammatory cardiomyopathy. The pooled outcomes were all-cause death and heart transplantation for inflammatory cardiomyopathy, left ventricular ejection fraction (LVEF), and left ventricular end diastolic dimension (LVEDD). Five trials involving 316 patients were included. Overall, immunosuppressive therapy was not superior to placebo and conventional therapy in the pooled outcome of all-cause death and heart transplantation (odds ratio [OR] 1.03, 95% confidence intervals [CI] 0.58 to 1.80) in the long-term. The pooled data showed that there might be a short-term beneficial effect on LVEF improvement (5.06%, 95% CI -0.07% to 10.18%) in patients receiving immunosuppressive therapy, but no beneficial effect on LVEDD either in the short-term (-0.87 mm; 95% CI, -8.29 to 6.55 in adult patients) or long-term (-0.52 mm, 95% CI -3.64 to 2.60 in adult patients) was observed. There is no evidence to suggest that immunosuppressive therapy has an effect on improving the survival of patients with inflammatory cardiomyopathy. Current therapy in inflammatory cardiomyopathy seems to be limited to supportive measures or transplantation.

The group B coxsackieviruses and myocarditis

The six serotypes of the group B coxsackieviruses (CVB) are common human enteroviruses linked etiologically to inflammatory cardiomyopathies. This has been demonstrated by molecular detection of enteroviral RNA in human heart tissue, serologic associations with disease, and virus isolation from cases of fulminant myocarditis. The murine model of CVB-associated myocarditis has demonstrated that CVB can be attenuated through mutations at different genomic sites. Human CVB3 isolates demonstrate varying degrees of cardiovirulence in the murine model; one site of virulence determination has been mapped to domain II of the 5' non-translated region. The interplay of CVB replication and the immune response to that replication in the heart is a complex interaction determining the extent to which the virus replication is limited and the degree to which a pathogenic inflammation of cardiac muscle occurs. Studies of CVB3-induced myocarditis in murine strains lacking subsets of the immune system or genes regulating the immune response have demonstrated a pivotal role of the T cell response to the generation of myocarditis. While CVB are associated with 20-25% of cases of myocarditis or cardiomyopathy, the severity of the disease and the existence of attenuated strains shown to generate protective immunity in animal models indicates that vaccination against the CVBs would be valuable.

[Clinical guidelines of the Spanish Society of Cardiology for the most frequent congenital cardiopathies]

The use of diagnostic and therapeutic techniques is very important to ensure optimum, effective treatment in patients with heart disease to thereby obtain an adequate cost-benefit relationship. The aim of establishing guidelines for the evaluation and management is to achieve this relationship, but these guidelines are difficult to establish in pediatric cardiology despite 50 years of experience in this field. At present a large group of patients may benefit from these guidelines due to the improvement in the diagnostic techniques and better treatment results in congenital heart disease in the newborn. Protocols have been established in some groups and in others in which this is not possible, descriptive analysis and therapeutic schedules have been determined.