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Aims MicroRNAs (miRNAs) might be used as prospective biomarkers for the identification of unexplained heart failure caused by a viral and/or inflammatory process. The aim of this study was to identify and to evaluate prognostic miRNAs in serum of patients with inflammatory heart diseases diagnosed by endomyocardial biopsies. Methods and results After TaqMan® OpenArray® screening of 754 unique circulating miRNAs in serum of biopsy‐proven patients [184 patients with inflammatory and/or virally induced myocardial diseases (DCMi), 25 patients with dilated cardiomyopathy (DCM), and 25 healthy donors], we identified seven miRNAs of interest (P

Human parvovirus B19 (B19V) is the predominant cardiotropic virus associated with dilated inflammatory cardiomyopathy (DCMi). Transcriptionally active cardiotropic B19V infection is clinically relevant and triggers adverse long-term mortality. During the study, we evaluated whether antiviral treatment with the nucleoside analogue telbivudine (LTD) is effective in suppressing transcriptional active B19V in endomyocardial biopsies (EMBs) of B19V positive patients and improving clinical outcomes. Seventeen B19V-positive patients (13 male, mean age 45.7 ± 13.9 years, mean left ventricular ejection fraction (LVEF) 37.7 ± 13.5%) with positive B19V DNA and transcriptional activity (B19V mRNA) in EMBs were treated with 600 mg/d LTD over a period of six months. Patients underwent EMBs before and after termination of the LTD treatment. B19V RNA copy numbers remained unchanged in 3/17 patients (non-responder) and declined or disappeared completely in the remaining 14/17 patients (responder) (p ≤ 0.0001). Notably, LVEF improvement was more significant in patients who reduced or lost B19V RNA (responder, p = 0.02) in contrast to non-responders (p = 0.7). In parallel, responder patients displayed statistically significant improvement in quality of life (QoL) questionnaires (p = 0.03) and dyspnea on exertion (p = 0.0006), reflecting an improvement in New York Heart Association (NYHA) Classification (p = 0.001). Our findings demonstrated for the first time that suppression of B19V transcriptional activity by LTD treatment improved hemodynamic and clinical outcome significantly. Thus, the present study substantiates the clinical relevance of detecting B19V transcriptional activity of the myocardium.

Plasminogen activator inhibitor-1 (PAI-1) has a cardioprotective function in mice by repressing cardiac fibrosis through TGF-β and plasminogen-mediated pathways. In addition it is known to be involved in the recruitment and polarization of monocytes/macrophages towards a M2 phenotype in cancer. Here, we investigated the expression of PAI-1 in human dilated cardiomyopathy (DCM) and inflammatory dilated cardiomyopathy (DCMi) and its effect on cardiac fibrosis and macrophage polarization. We retrospectively analyzed endomyocardial biopsies (EMBs) of patients with DCM or DCMi for PAI-1 expression by immunohistochemistry. Furthermore, EMBs were evaluated for the content of fibrotic tissue, number of activated myofibroblasts, TGF-β expression, as well as for M1 and M2 macrophages. Patients with high-grade DCMi (DCMi-high, CD3+ lymphocytes > 30 cells/mm2) had significantly increased PAI-1 levels compared to DCM and low-grade DCMi patients (DCMi-low, CD3+ lymphocytes = 14–30 cells/mm2) (15.5 ± 0.4% vs. 1.0 ± 0.1% and 4.0 ± 0.1%, p ≤ 0.001). Elevated PAI-1 expression in DCMi-high subjects was associated with a diminished degree of cardiac fibrosis, decreased levels of TGF-β and reduced number of myofibroblasts. In addition, DCMi-high patients revealed an increased proportion of non-classical M2 macrophages towards classical M1 macrophages, indicating M2 macrophage-favoring properties of PAI-1 in inflammatory cardiomyopathies. Our findings give evidence that elevated expression of cardiac PAI-1 in subjects with high-grade DCMi suppresses fibrosis by inhibiting TGF-β and myofibroblast activation. Moreover, our data indicate that PAI-1 is involved in the polarization of M2 macrophages in the heart. Thus, PAI-1 could serve as a potential prognostic biomarker and as a possible therapeutic target in inflammatory cardiomyopathies.

Erythroparvovirus (B19V) genomes have been detected in various organs of infected individuals including endothelial cells of the heart muscle. However, the role of B19V as a causative pathogen of myocardial damage is still unknown. The majority of reports focus on the presence of viral DNA ignoring proof of viral RNAs as important markers for viral activity. During this study, we established (RT-) qPCR to characterize expression of B19V RNAs (NS1 and VP1/2) in endomyocardial biopsies (EMBs) of 576 patients with unexplained heart failure. 403/576 (70%) EMBs were positive for B19V DNA. B19V mRNAs NS1 and/or VP1/2, indicating viral activity, could be detected in 38.5% of B19V DNA positive samples using the newly established B19V RT-PCRs. 22.1% of samples were characterized by only NS1 mRNA detection while 6.0% revealed only VP1/2 mRNA expression. Detection of both intermediates was successful in 10.4% of samples. Applying the molecular testing, our study revealed that a high proportion (38.5%) of B19V DNA positive EMBs was characterized by viral transcriptional activity. Further prospective studies will evaluate relevance of viral transcription intermediates as a diagnostic marker to differentiate between latent B19V infection and clinically relevant transcriptionally active B19V-infection of the heart muscle.

Highlights • SARS-CoV-2 viral RNA positivity in the heart is present after a latent period of four weeks after onset of pulmonary symptoms in a COVID-19 patient. • Intramyocardial inflammation is a complication in a patient affected by COVID-19. • Histopathological and clinical improvement of the patient were in accordance with viral clearance on follow-up biopsy investigation., Emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has reached pandemic level. Cardiovascular complications in COVID-19 have been reported frequently, however, evidence for causal relationship has not been established. We describe detection of SARS-CoV-2 viral genomes in a patient with heart failure symptoms investigating endomyocardial biopsy following a latent period of four weeks after onset of pulmonary symptoms. Viral infection was accompanied by myocardial inflammation indicating infection of the heart muscle.

Aims: The diagnostic approach to idiopathic giant-cell myocarditis (IGCM) is based on identifying various patterns of inflammatory cell infiltration and multinucleated giant cells (GCs) in histologic sections taken from endomyocardial biopsies (EMBs). The sampling error for detecting focally located GCs by histopathology is high, however. The aim of this study was to demonstrate the feasibility of gene profiling as a new diagnostic method in clinical practice, namely in a large cohort of patients suffering from acute cardiac decompensation. Methods and Results: In this retrospective multicenter study, EMBs taken from n = 427 patients with clinically acute cardiac decompensation and suspected acute myocarditis were screened (mean age: 47.03 &plusmn, 15.69 years). In each patient, the EMBs were analyzed on the basis of histology, immunohistology, molecular virology, and gene-expression profiling. Out of the total of n = 427 patient samples examined, GCs could be detected in 26 cases (6.1%) by histology. An established myocardial gene profile consisting of 27 genes was revealed, this was narrowed down to a specified profile of five genes (CPT1, CCL20, CCR5, CCR6, TLR8) which serve to identify histologically proven IGCM with high specificity in 25 of the 26 patients (96.2%). Once this newly established profiling approach was applied to the remaining patient samples, an additional n = 31 patients (7.3%) could be identified as having IGCM without any histologic proof of myocardial GCs. In a subgroup analysis, patients diagnosed with IGCM using this gene profiling respond in a similar fashion to immunosuppressive therapy as patients diagnosed with IGCM by conventional histology alone. Conclusions: Myocardial gene-expression profiling is a promising new method in clinical practice, one which can predict IGCM even in the absence of any direct histologic proof of GCs in EMB sections. Gene profiling is of great clinical relevance in terms of a) overcoming the sampling error associated with purely histologic examinations and b) monitoring the effectiveness of therapy.

Aims Since December 2019, the novel coronavirus SARS‐CoV‐2 has spread rapidly throughout China and keeps the world in suspense. Cardiovascular complications with myocarditis and embolism due to COVID‐19 have been reported. SARS‐CoV‐2 genome detection in the heart muscle has not been demonstrated so far, and the underlying pathophysiological mechanisms remain to be investigated. Methods and results Endomyocardial biopsies (EMBs) of 104 patients (mean age: 57.90 ± 16.37 years; left ventricular ejection fraction: 33.7 ± 14.6%, sex: n = 79 male/25 female) with suspected myocarditis or unexplained heart failure were analysed. EMB analysis included histology, immunohistochemistry, and detection of SARS‐CoV‐2 genomes by real‐time reverse transcription polymerase chain reaction in the IKDT Berlin, Germany. Among 104 EMBs investigated, five were confirmed with SARS‐CoV‐2 infected by reverse real‐time transcriptase polymerase chain reaction. We describe patients of different history of symptoms and time duration. Additionally, we investigated histopathological changes in myocardial tissue showing that the inflammatory process in EMBs seemed to permeate vascular wall leading to small arterial obliteration and damage. Conclusions This is the first report that established the evidence of SARS‐CoV‐2 genomes detection in EMBs. In these patients, myocardial injury ischaemia may play a role, which could explain the ubiquitous troponin increases. EMB‐based identification of the cause of myocardial injury may contribute to explain the different evolution of complicated SARS‐CoV‐2‐infection and to design future specific and personalized treatment strategies.

Immunosuppression by retroviruses including the human immunodeficiency virus—1 (HIV-1) is well known, however the mechanisms how retroviruses induce this immunosuppression is not fully investigated. It was shown that non-infectious retroviral particles as well as retroviral or recombinant retroviral transmembrane envelope (TM) proteins demonstrated immunosuppressive properties. The same was shown for peptides corresponding to a highly conserved domain in the TM protein. This domain is called immunosuppressive (ISU) domain and it induces modulation of the cytokine release of peripheral blood mononuclear cells (PBMCs) from healthy donors. In addition, it changes the gene expression of these cells. Common indications for the immunosuppressive activity were tumour growth in vivo and interleukin—10 (IL-10) release from human PBMCs in vitro. Single mutations in the ISU domain abrogated the immunosuppressive activity. In order to develop a new model system for the expression of the ISU domain and presentation to PBMCs which is not prone to possible endotoxin contaminations, two expression systems were developed. In the first system, designated pOUT, retroviral proteins containing the ISU domain were expressed and released into the cell culture medium, and in the second system, tANCHOR, the ISU domain was presented by a tetraspanin-anchored sequence on the cell surface of human cells. Both systems were exploited to express the wild-type (wt) ISU domains of HIV-1, of the porcine endogenous retrovirus (PERV) and of the murine leukaemia virus (MuLV) as well as to express mutants (mut) of these ISU domains. PERV is of special interest in the context of virus safety of xenotransplantation using pig organs. Expression of the TM proteins was demonstrated by confocal laser scanning microscopy, ELISA and Western blot analyses using specific antibodies. However, when cells expressing and releasing the ISU were co-incubated with human PBMCs, no increased production of IL-10 was observed when compared with the mutants. Similar results were obtained when the released TM proteins were concentrated by immunoprecipitation and added to PBMCs. We suggest that the absence of IL-10 induction can be explained by a low amount of protein, by the lack of a biologically active conformation or the absence of additional factors.