Myocarditis: causes, mechanisms, and evolving therapies

Effect of Astragalus injection treatment for viral myocarditis: a systematic review and meta-analysis

BACKGROUND

Astragalus injection has been utilized in traditional Chinese medicine to treat a variety of diseases. The purpose of this systematic review was to evaluate the effectiveness of Astragalus injection in the treatment of viral myocarditis.

METHODS

English databases such as PubMed, Cochrane Library, and EMBASE, and Chinese databases of Sino Med, China National Knowledge Infrastructure (CNKI), the VIP Information Resource Integration Service Platform, and Wanfang Data Information Site, were searched from their inception until May 1, 2024. The outcome measures of this study included the effectiveness rate, creatine kinase (CK), aspartate aminotransferase (AST), creatine kinase Isoenzyme (CK-MB), lactate dehydrogenase (LDH), cardiac troponin I (cTnI), and electrocardiogram (ECG).

RESULTS

Twenty-six studies were included in this analysis, comprising a total of 2793 patients. Meta-analyses indicated that, compared to standard treatment alone, the Astragalus injection group demonstrated significant advantages, achieving an effectiveness rate of 92.79% (1094 cases). In contrast, the control group, which included 1108 cases, had an effectiveness rate of 77.71% (861 cases). Additionally, the Astragalus injection group exhibited the following benefits for patients affected by viral myocarditis: decreasing ∆AST [weighted mean difference (WMD) = - 14.23, 95% confidence interval (CI) (- 24.17, - 4.30), P < 0.05]; ∆CK [weighted mean difference (WMD) = - 34.84, 95% confidence interval (CI) (- 48.03, - 21.65), P < 0.05], lowering ∆CK-MB [WMD = - 7.64, 95% CI (- 9.30, - 5.99), P < 0.001], ∆cTnl [WMD = - 0.18, 95% CI (- 0.27, - 0.10), P < 0.001], ∆LDH [WMD = -41.93, 95% CI (- 55.97, - 27.90), P < 0.05], and ∆cTnI [WMD = - 0.18, 95% CI (- 0.28, - 0.08), P < 0.05].

CONCLUSION

Astragalus injection may have a therapeutic effect in patients with viral myocarditis by reducing levels of AST, CK, CK-MB, LDH, and cTnI, improving ECG results, and increasing the overall effectiveness rate for those affected by this condition.

TRIAL REGISTRATION

This study registered with PROSPERO before conducting the systematic review. The registration number is CRD42021239660.

Artificial intelligence and myocarditis-a systematic review of current applications

Myocarditis, marked by heart muscle inflammation, poses significant clinical challenges. This study, guided by PRISMA guidelines, explores the expanding role of artificial intelligence (AI) in myocarditis, aiming to consolidate current knowledge and guide future research. Following PRISMA guidelines, a systematic review was conducted across PubMed, Cochrane Reviews, Scopus, Embase, and Web of Science databases. MeSH terms including artificial intelligence, deep learning, machine learning, myocarditis, and inflammatory cardiomyopathy were used. Inclusion criteria involved original articles utilizing AI for myocarditis, while exclusion criteria eliminated reviews, editorials, and non-AI-focused studies. The search yielded 616 articles, with 42 meeting inclusion criteria after screening. The identified articles, spanning diagnostic, survival prediction, and molecular analysis aspects, were analyzed in each subsection. Diagnostic studies showcased the versatility of AI algorithms, achieving high accuracies in myocarditis detection. Survival prediction models exhibited robust discriminatory power, particularly in emergency settings and pediatric populations. Molecular analyses demonstrated AI's potential in deciphering complex immune interactions. This systematic review provides a comprehensive overview of AI applications in myocarditis, highlighting transformative potential in diagnostics, survival prediction, and molecular understanding. Collaborative efforts are crucial for overcoming limitations and realizing AI's full potential in improving myocarditis care.

Formoterol Reduces the Pro-Inflammatory Phenotype by Enhancing the Activity of Glutaminase in Monocyte-Derived Macrophages in the CVB3-Induced Viral Myocarditis

BACKGROUND

Viral myocarditis (VMC) plays a significant role in heart failure, and there is currently a shortage of available targeted treatments. Macrophage phenotype and function are closely associated with the beta-2 adrenergic receptor (β2-AR).

METHOD

This research employed a BALB/c mouse model of VMC generated using Coxsackievirus B3 (CVB3), and the β2-AR agonist formoterol was administered as treatment. A bioinformatic analysis was conducted to identify the β2-AR in CCR2+MHCIIhigh monocyte-derived macrophages (MoMFs). Echocardiography and histopathological assessments were utilized to evaluate cardiac function and inflammation. The enzymatic activity of glutaminase (GLS) was quantified. Flow cytometry was employed to characterize the phenotype and function of the macrophages.

RESULT

Our study revealed that formoterol treatment effectively mitigated cardiac inflammation and fibrosis, improved cardiac function, and prolonged survival compared to the VMC group. Formoterol reduced the infiltration of CCR2+MHCIIhigh MoMFs in the heart, inhibited M1 phenotypic expression and activity, and reduced the percentage of Ly6Chigh monocytes in circulation. Additionally, formoterol stimulated M2 phenotypic expression and activity and increased the percentage of Ly6Clow monocytes in circulation. Additionally, the combination of NICB3344, a C-C motif chemokine receptor 2 inhibitor, with formoterol did not exhibit synergistic effects on reducing cardiac pathological scores or enhancing cardiac function. In vitro studies involving the use of lipopolysaccharide (LPS)-induced bone marrow-derived macrophages, revealed the ability of formoterol to suppress the M1 phenotype and functions induced by LPS while promoting the M2 phenotype and functions. Nevertheless, the observed effects were negated by the introduction of the GLS inhibitor BPTES.

CONCLUSION

Formoterol potentially serves as a significant metabolic regulator in the differentiation process of cardiac MoMFs, influencing this process by controlling GLS activity. Targeting β2-AR exhibits potential as an effective approach for managing VMC. It is essential to acknowledge that these findings were derived under specific experimental conditions, with the current conclusions predominantly based on animal models. Future research is necessary to further investigate the feasibility of formoterol in clinical practice.

A Narrative Review of Preclinical In Vitro Studies Investigating microRNAs in Myocarditis

According to the World Health Organization's statement, myocarditis is an inflammatory myocardium disease. Although an endometrial biopsy remains the diagnostic gold standard, it is an invasive procedure, and thus, cardiac magnetic resonance imaging has become more widely used and is called a non-invasive diagnostic gold standard. Myocarditis treatment is challenging, with primarily symptomatic therapies. An increasing number of studies are searching for novel diagnostic biomarkers and potential therapeutic targets. Microribonucleic acids (miRNAs) are small, non-coding RNA molecules that decrease gene expression by inhibiting the translation or promoting the degradation of complementary mRNAs. Their role in different fields of medicine has been recently extensively studied. This review discusses all relevant preclinical in vitro studies regarding microRNAs in myocarditis. We searched the PubMed database, and after excluding unsuitable studies and clinical and preclinical in vivo trials, we included and discussed 22 preclinical in vitro studies in this narrative review. Several microRNAs presented altered levels in myocarditis patients in comparison to healthy controls. Moreover, microRNAs influenced inflammation, cell apoptosis, and viral replication. Finally, microRNAs were also found to determine the level of myocardial damage. Further studies may show the vital role of microRNAs as novel therapeutic agents or diagnostic/prognostic biomarkers in myocarditis management.

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.

Regulatory T cells and cardiovascular diseases

ABSTRACT

Inflammation is a major underlying mechanism in the progression of numerous cardiovascular diseases (CVDs). Regulatory T cells (Tregs) are typical immune regulatory cells with recognized immunosuppressive properties. Despite the immunosuppressive properties, researchers have acknowledged the significance of Tregs in maintaining tissue homeostasis and facilitating repair/regeneration. Previous studies unveiled the heterogeneity of Tregs in the heart and aorta, which expanded in CVDs with unique transcriptional phenotypes and reparative/regenerative function. This review briefly summarizes the functional principles of Tregs, also including the synergistic effect of Tregs and other immune cells in CVDs. We discriminate the roles and therapeutic potential of Tregs in CVDs such as atherosclerosis, hypertension, abdominal arterial aneurysm, pulmonary arterial hypertension, Kawasaki disease, myocarditis, myocardial infarction, and heart failure. Tregs not only exert anti-inflammatory effects but also actively promote myocardial regeneration and vascular repair, maintaining the stability of the local microenvironment. Given that the specific mechanism of Tregs functioning in CVDs remains unclear, we reviewed previous clinical and basic studies and the latest findings on the function and mechanism of Tregs in CVDs.

Clinically Suspected Acute Myocarditis in the First Trimester of Twin Gestation: A Case Report

Acute myocarditis (AM) in early pregnancy is a rare disease. Its clinical presentation varies from asymptomatic disease to cardiogenic shock and death. A 28-year-old woman, 12 weeks primigravida of a dichorionic and diamniotic pregnancy, was admitted for hyperemesis gravidarum, associated with a common cold-like condition. During hospitalization, she developed new-onset sinus tachycardia and dyspnea. An electrocardiogram revealed sinus tachycardia and diffuse ST-segment elevation. Laboratory tests showed elevated levels of troponin and pro-B-type natriuretic peptide. Pelvic obstetric ultrasound and chest X-ray were normal. Speckle-tracking echocardiography showed mild apical hypokinesia with preserved left ventricular ejection fraction. In view of these findings, AM was suspected, and cardiac magnetic resonance imaging was highly suggestive of AM. The patient had a favorable recovery without cardiovascular or obstetric complications.