Isolated cardiac sarcoidosis (iCS), defined by granulomatous inflammation limited to the myocardium, represents the most diagnostically challenging and prognostically adverse form of sarcoidosis. As it is fundamentally a diagnosis of exclusion, iCS diagnosis relies on the absence of extracardiac sarcoid and the integration of multimodality imaging, endomyocardial biopsy, and molecular testing, each with inherent limitations. Cardiac magnetic resonance and positron emission tomography provide complementary assessment of inflammation, fibrosis, and ventricular function, enhancing diagnostic confidence. Electroanatomic mapping-guided biopsy may improve histologic yield, whereas genetic testing helps exclude phenocopies such as arrhythmogenic, hypertrophic, or dilated cardiomyopathies. Circulating biomarkers remain non-specific but may complement imaging-based algorithms. Future research should focus on harmonized imaging protocols, non-FDG radiotracers, and molecular tissue profiling to refine activity assessment and guide therapy. Multimodal, probability-based frameworks represent the most promising approach for earlier, more accurate diagnosis and risk stratification in iCS.

BACKGROUND:Inflammatory cardiomyopathy (CMi) is a major cause of heart failure, but the prognostic significance of different inflammatory phenotypes remains uncertain. Advanced immunohistochemical analyses of endomyocardial biopsies (EMBs) may improve risk stratification. OBJECTIVES:This study aims to evaluate the prognostic value of quantitative inflammatory phenotypes in virus-negative CMi. METHODS:Among 1,467 patients with unexplained heart failure undergoing EMB, 478 virus-negative patients were included and followed for a median of 26 months (Q1-Q3: 10-49 months). None received immunosuppressive therapy. Myocardial inflammation was characterized by histology and immunohistochemistry (CD3-positive, macrophage-1 antigen positive, CD45R0-positive, leukocyte function antigen-1 positive), with prognostic thresholds defined for each marker. Associations with mortality, deterioration in left ventricular ejection fraction, and persistent systolic dysfunction were evaluated using multivariable Cox regression and Kaplan-Meier analyses. RESULTS:Elevated CD3-positive T cells (≥7.8 cells/mm2) were the strongest independent predictor of mortality and deterioration of left ventricular ejection fraction (HR: 1.037 [95% CI: 1.027-1.047]; P < 0.001). Increased macrophage-1 antigen positive (≥40 cells/mm2), CD45R0-positive (≥21 cells/mm2), or leukocyte function antigen-1-positive (≥12.5 cells/mm2) cell counts were also associated with poorer survival and ventricular function (P < 0.01), even without elevated CD3 cells. These additional markers identified intramyocardial inflammation in 26% of patients who would otherwise not have been diagnosed. CD3-positive inflammation was associated with a higher hazard of the outcome (HR: 5.15 [95% CI: 3.4-7.67]; P < 0.001), while CD3-negative inflammation was also associated with an increased risk compared with patients without inflammation (HR: 2.44 [95% CI: 1.31-4.55]; P > 0.01). Higher quantitative immune cell counts were associated with progressively worse clinical outcomes, indicating a dose-response relationship between inflammatory burden and prognosis. CONCLUSIONS:Quantitative inflammatory phenotyping of EMB provides independent prognostic information in virus-negative CMi. These findings reflect the natural course of the disease without treatment and support refined biopsy-based diagnostics for improved risk stratification and personalized treatment strategies.

Myocarditis and inflammatory cardiomyopathy are inflammatory diseases of the heart muscle that can have both infectious and non-infectious causes. They can be caused by an unresolved viral infection or other infection, or they can be autoimmune, toxic, or allergic in nature. The specific identification of the pathogen and/or confirmation of inflammation can only be achieved through direct tissue analysis using endomyocardial biopsy (EMB), as neither detection of the virus nor assessment of the quality and intensity of the inflammation is possible using non-invasive methods. Accordingly, the removal and analysis of an EMB is considered the diagnostic gold standard in international guidelines and statements. The sudden onset of atypical angina pectoris and initially exertion-dependent dyspnea, as well as arrhythmias, pericardial effusion, and progressive symptoms of heart failure, indicate an acute inflammatory process of the myocardium. In addition, nonspecific symptoms such as fatigue and reduced physical performance may also occur. Diagnostic evaluation includes an electrocardiogram (ECG), cardiac imaging, and laboratory tests. The analysis of the EMB is crucial for a definitive diagnosis and thus for the initiation of an etiology-based, specific and personalized therapy. This includes histological and immunohistochemical inflammation diagnostics as well as molecular virological diagnostics. These enable both the detection of viruses and the assessment of transcriptional virus activity. New analyses using metagenomic next generation sequencing (NGS) techniques provide insights of enormous diagnostic and therapeutic relevance. This applies both to the spectrum of detectable pathogens and to the possibility of confirming transcriptional viral activity. In addition, gene expression profiling enables the differentiation of specific forms of myocardial inflammation (e.g., giant cell myocarditis, cardiac sarcoidosis, and eosinophilic myocarditis) and reduces the influence of "sampling errors" in focal inflammatory processes. The treatment of heart failure or ventricular arrhythmias is always symptomatic according to general evidence-based guidelines. In severe cases, mechanical circulatory support or even a heart transplant may be necessary. Patients with histologically confirmed myocardial inflammation or intramyocardial viral infection can be offered specific, causal, and personalized therapy. These patients can be successfully treated with immunosuppressive or antiviral therapy, which significantly improves the prognosis of the disease.

AIMS:miRNAs, small non-coding RNAs, play key roles in gene regulation, cell differentiation and tissue development. They influence viral infection outcomes by directly interacting with viral genomes or modifying the host microenvironment. This study demonstrates miRNAs' ability to selectively suppress transcriptionally active erythroparvovirus, highlighting their potential in antiviral therapies. METHODS AND RESULTS:Seventy-five endomyocardial biopsy (EMB) specimens from patients with unexplained heart failure were analysed. The samples included 19 with dilated cardiomyopathy and inflammation (DCMi), 12 with dilated cardiomyopathy (DCM), 25 with inflammation and active erythroparvovirus infection, 13 with active erythroparvovirus infection only and 6 from undiagnosed patients as controls. miRNA expression was measured using TaqMan assays. miR-98, miR-222, miR-106b and miR-197 were significantly upregulated in patients with transcriptionally active erythroparvovirus infection, independent of inflammation (P < 0.005). These miRNAs differentiated these patients from all other groups with over 90% specificity. CONCLUSIONS:These specific miRNAs offer a novel diagnostic tool for active erythroparvovirus infections and hold promise as therapeutic targets, providing safer alternatives to traditional antiviral treatments.

AIMS:The analysis of endomyocardial biopsies (EMB) is a prerequisite for a definitive diagnosis in patients with unexplained heart failure (HF). The use of machine learning (ML) methods may help to identify high-risk patients and to initiate therapy. In this study, we develop ML models for risk stratification of parvovirus B19 (B19V) positive patients with HF based on key features from multiparametric EMB analyses. METHODS AND RESULTS:We retrospectively enrolled 263 B19V-positive patients with HF (mean age 51 ± 15 years, 62% male) and followed them over a median period of 22 months (interquartile range 4-35 months). All-cause mortality, left ventricular (LV) deterioration and persistent LV systolic dysfunction were used as clinical combined endpoint. EMB were analysed for a variety of inflammatory and infectious markers, and patient prognosis was assessed using ML methods (logistic regression, random forest, support vector machines and gradient boosting). Detection of intramyocardial inflammation and B19V viral activity was associated with poor clinical outcome (hazard ratio 3.50, 95% confidence interval 1.96-6.23, p < 0.001). Linear combination of demographic and clinical data with multiparametric EMB markers increased the prognostic performance (area under the curve [AUC] = 0.724) compared to using single features (AUC = 0.667). The use of gradient boosting ML methods significantly improved the accuracy of risk prediction (AUC = 0.926). CONCLUSIONS:Intramyocardial inflammation and B19V viral activity were detected more frequently in patients with poor clinical outcome, suggesting that they are risk factors for death and LV dysfunction. Using multiparametric EMB data, we present an ML-based prognostic tool that can determine the clinical outcome of patients with a high degree of accuracy. This could be helpful in assessing the progression of the disease and making appropriate treatment decisions.

Heart failure with preserved ejection fraction (HFpEF) accounts for half of heart failure cases and is characterised by reduced pericyte coverage. While the contributions of other cardiac cell types to HFpEF are well-studied, the role of pericytes remains less understood. Using murine single-nucleus RNA-sequencing to study cardiac pericytes in HFpEF, we identified reduced STAT3 expression as a hallmark of HFpEF pericytes. Mechanistic studies in vitro revealed that STAT3 deletion induces cellular senescence and impairs pericyte adhesion, recapitulating HFpEF-like characteristics. These findings suggest that STAT3 is crucial for maintaining pericyte homeostasis and highlight its reduction as a potential driver of pericyte loss, a defining feature of HFpEF.

Viral infections are a major cause of inflammatory heart disease, but conventional polymerase chain reaction (PCR) often fails to detect the causative pathogens, limiting diagnostic and therapeutic decisions. We investigated whether targeted metagenomic next-generation sequencing (NGS) improves virus detection in endomyocardial biopsies (EMB) compared to standard PCR, and examined the clinical implications of undetected viral infections in heart failure. EMB samples from 108 patients with unexplained heart failure underwent histologic and immunohistochemical analysis to assess myocardial inflammation. All samples were tested for common cardiotropic viruses using PCR. Targeted metagenomic NGS was performed in 36 PCR-positive and 72 PCR-negative cases. Virus prevalence and transcriptional activity were compared with PCR results and correlated with myocardial inflammation and left ventricular ejection fraction (LVEF). NGS identified all 45 viruses previously detected by PCR and revealed 31 additional viral genomes in PCR-positive patients, increasing diagnostic yield by 69%. In PCR-negative patients, NGS identified viral genomes in 56% of cases, uncovering a significant number of previously undiagnosed infections. Frequently detected viruses included parvovirus B19, Epstein-Barr virus, human herpesvirus 6, cytomegalovirus, and adenovirus, as well as less expected agents such as herpesvirus 7/8, adenovirus-associated virus, and pegivirus C. Transcriptionally active parvovirus B19 was more often detected by NGS than PCR (31% vs. 14%). Patients with NGS-confirmed viral infections showed significantly reduced LVEF compared to virus-negative individuals. Targeted metagenomic sequencing substantially improves virus detection in EMB samples and reveals clinically relevant infections missed by PCR. These results support the integration of NGS into diagnostic workflows for virus-associated heart failure in order to better guide clinical management. Targeted metagenomic sequencing of endomyocardial biopsies enables comprehensive, broad-range detection of cardiotropic viruses in patients with heart failure. Metagenomic sequencing demonstrates markedly higher sensitivity than conventional PCR and can distinguish latent from active viral infections. Viral genomes were frequently detected in patients with reduced left ventricular function, indicating a substantial contribution of unrecognized infections to the pathogenesis of heart failure. Targeted metagenomic sequencing provides a novel diagnostic tool for more accurate etiological classification of heart failure, thereby supporting more informed clinical decision-making. Identification of specific viral genomes, including the ability to distinguish latent from active infections, provides a basis for antiviral or immunomodulatory therapy decisions. These findings support incorporating metagenomic sequencing into diagnostic workflows to improve risk stratification and management of patients with heart failure.

Abstract Background Parvovirus B19 (B19V) is the most common type of virus found in endomyocardial biopsies (EMB) from patients with inflammatory heart disease. However, the detection of genomic B19V-DNA appears to have little clinical significance and is often considered an incidental finding. Recent analyses of a large cohort of B19V-positive patients revealed that the detection of RNA transcripts rather than DNA is of clinical importance, as B19V-RNA-positive patients have a significantly worse cardiovascular outcome. Here, we applied machine learning (ML) methods to assess the impact of B19V transcriptional activity on cardiac inflammation and patient clinical outcome. Methods and results A total of 305 patients with a known clinical course and a positive endomyocardial B19V-DNA test were included in this study. Follow-up measurements of the B19V-specific transcripts VP1/2 and NS1 revealed significantly worse clinical courses than in patients without B19V-RNA detection (P=0.019, hazard ratio (95% CI)=1.62 (1.10-2.57)). LVEF at follow-up was significantly lower in patients with detected B19V-RNA (P=0.007), and adverse events such as worsening LV function (P=0.003) or stable systolic dysfunction (P=0.013) were more frequent in this group. Importantly, analysis of inflammatory markers in EMB showed no difference in patients with and without RNA detection (P=0.432), suggesting that the deterioration in clinical outcome was related to B19V transcriptional activity rather than an increase in inflammation. The analysis of area under the receiver operating characteristic curve (AUROC) of B19V-RNA-negative patients revealed that the macrophage marker MAC-1 (AUROC=0.66, P=0.002) was the single most prognostically relevant parameter, while the T cell marker CD3 (AUROC=0.73, P<0.001) was identified as the most prognostically relevant marker in B19V-RNA-positive patients. The linear combination of several inflammatory markers increased the AUROC value to 0.67 in B19V-RNA-negative patients and to 0.74 in B19V-RNA-positive patients. To further increase prognostic accuracy, we trained ML models on features derived from EMB inflammatory markers. For the prediction of major adverse cardiac events within 60 months, the best ML-models achieved an AUROC of 0.87 in B19V-RNA-positive and of 0.86 in B19V-RNA-negative patients, while models that neglect the differentiation of patients with regard to the presence of B19V RNA transcripts only achieved an AUROC of up to 0.76. Conclusions These results show that B19V transcriptional activity is an independent risk marker for adverse cardiac events in patients with viral cardiomyopathy and thus confirm the clinical-therapeutic importance of myocardial biopsy. Furthermore, we present an ML-based algorithm that accurately indicates disease progression in B19V-positive cardiomyopathy patients and is thus helpful for appropriate therapy recommendation.

Abstract Background Viral infection of the heart muscle is a common cause of myocarditis and viral persistence can lead to chronic inflammatory cardiomyopathies (DCMi). A number of viruses including parvovirus B19 (B19V), adenovirus (AdV), cytomegalovirus (CMV), Epstein-Barr virus (EBV), herpes virus 6 (HHV-6) and enteroviruses (EV) are known to infect the myocardium, but their prevalence and role in persisting DCMi are not well understood. Virological etiologies can only be determined via endomyocardial biopsy (EMB), but the low tissue amount limits the number of conventional viral nucleic acid tests (virus-specific PCR) that can be performed in parallel. This study aimed to detect known and novel cardiotropic viruses in EMB of DCMi patients using a targeted next generation sequencing (NGS) approach. Methods A cohort of 33 patients with inflammatory cardiomyopathy (DCMi) (LVEF=29±12%) were retrospectively analyzed and compared to previous results of virus-specific PCR. DNA and RNA extracted from EMB were used for sequencing library preparation, and viral nucleic acids were enriched via a custom myBaits hybridization capture approach. Enriched libraries were sequenced on an Illumina MiSeq-platform in paired-end mode (500.000 reads/sample), and reads were taxonomically classified via Kraken2 and mapped against viral reference genomes using BWA-MEM2 or HiSat2, and subsequently deduplicated. Viral reads detected via both Kraken2 and mapping were classified as valid. Results Targeted NGS confirmed 19 out of 22 (86%) of the previous PCR-based viral detections. However, NGS was able to detect B19V DNA and RNA in an additional 11 and 15 patient samples respectively; CMV DNA/RNA in additional 5 and 4 samples respectively; EBV DNA/RNA in additional 5 and 1 samples respectively; and HHV-6 DNA/RNA in additional 3 and 1 samples respectively. Furthermore, viral reads of adenovirus type 2, adenovirus-associated virus type 2 (AAV-2), herpes viruses 7 and 8, and human parvovirus 4 were also found among the cohort. Thus, targeted NGS was able to identify 82 viral infections in a cohort of 33 DCMi patients, while only 22 were found using routine PCR tests. For routinely tested B19V, the use of the new NGS diagnostic approach improved sensitivity by 42% and specificity by 72%. Conclusions The presented NGS method represents a powerful new tool for the diagnosis of viral and inflammatory heart disease. The sensitivity is significantly higher than with conventional PCR approaches and the taxonomic classification is more specific. This enables the detection of previously false-negative routine viruses as well as potentially new cardiotropic pathogens from limited bioptic patient material – thus significantly increasing the diagnostic yield of EMB. In addition, our study demonstrates a high prevalence of non-enteroviral cardiotropic viruses in DCMi patients, shedding new light on the etiology of this heterogenous diseases and paving the way for more specific future treatments.

Aims: Myocardial inflammation is increasingly detected noninvasively by tissue mapping with cardiovascular magnetic resonance (CMR). Intraindividual agreement with endomyocardial biopsy (EMB) or markers of myocardial injury, high-sensitive cardiac troponin (hs-cTnT) in patients with clinically suspected viral myocarditis is incompletely understood. Methods: Prospective multicenter study of consecutive patients with clinically suspected myocarditis who underwent blood testing for hs-cTnT, CMR, and EMB as a part of diagnostic workup. EMB was considered positive based on immunohistological criteria in line with the European Society of Cardiology (ESC) definitions. CMR diagnoses employed tissue mapping using sequence-specific cut-off for native T1 and T2 mapping; active inflammation was defined as T1 >= 2 standard deviation (SD) and T2 >= 2 SD above the mean of normal range. HscTnT of greater than 13.9 ng/L was considered significant. Results: A total of 114 patients (age (mean +/- SD) 54 +/- 16, 65% males) were included, of which 79 (69%) had positive EMB criteria, 64 (56%) CMR criteria, and a total of 58 (51%) positive troponin. Agreement between EMB and CMR diagnostic criteria was poor (CMR vs ESC: area under the curve (AUC): 0.51 (0.39-0.62)). The agreement between a significant hs-cTnT rise and CMR-based diagnosis of myocarditis was good (AUC: 0.84 (0.68-0.92); p < 0.001), but poor for EMB (0.50 (0.40-0.61). Hs-cTnT was significantly associated with native T1 and T2, high-sensitive C-reactive protein, and N-terminal pro-hormone brain natriuretic peptide (r = 0.37, r = 0.35, r = 0.30, r = 0.25; p < 0.001), but not immunohistochemical criteria or viral presence. Conclusion: In clinically suspected viral myocarditis, all diagnostic approaches reflect the pathophysiological elements of myocardial inflammation; however, the differing underlying drivers only partially overlap. The EMB

The Epstein-Barr virus (EBV) is frequently found in endomyocardial biopsies (EMBs) from patients with heart failure, but the detection of EBV-specific DNA has not been associated with progressive hemodynamic deterioration. In this paper, we investigate the use of targeted next-generation sequencing (NGS) to detect EBV transcripts and their correlation with myocardial inflammation in EBV-positive patients with heart failure with reduced ejection fraction (HFrEF). Forty-four HFrEF patients with positive EBV DNA detection and varying degrees of myocardial inflammation were selected. EBV-specific transcripts from EMBs were enriched using a custom hybridization capture-based workflow and, subsequently, sequenced by NGS. The short-read sequencing revealed the presence of EBV-specific transcripts in 17 patients, of which 11 had only latent EBV genes and 6 presented with lytic transcription. The immunohistochemical staining for CD3+ T lymphocytes showed a significant increase in the degree of myocardial inflammation in the presence of EBV lytic transcripts, suggesting a possible influence on the clinical course. These results imply the important role of EBV lytic transcripts in the pathogenesis of inflammatory heart disease and emphasize the applicability of targeted NGS in EMB diagnostics as a basis for specific treatment.

Abstract Background Endomyocardial biopsy (EMB) is an important diagnostic tool for evaluating various cardiac diseases such as myocarditis and storage disorders as well as for the monitoring heart transplant patients. Despite advances in non-invasive imaging techniques to characterize myocardial tissue, EMB remains the gold standard for definitive diagnosis and initiation of specific therapy. Here we report EMB laboratory results from over 8,000 patients and demonstrate the diagnostic utility of EMB. Methods and results We retrospectively reviewed EMB analyses performed at our institution. EMBs for monitoring graft rejection were not included in this study. Clinical data, suspected clinical diagnoses and EMB-based laboratory results were collected. Histopathological, immunohistochemical and molecular biology biopsy findings were recorded and reviewed for degree of concordance with clinical diagnosis. In total, EMBs from N=8,085 consecutive patients with unexplained heart failure were analyzed. The comprehensive EMB analysis revealed that N=616 (7.6%) patients had cardiac storage disease, most of whom had cardiac amyloidosis (N=606). N=357 (4.4%) patients were diagnosed with acute forms of myocarditis, including N=95 cases with active myocarditis, N=148 cases with giant cell myocarditis, N=95 cases with sarcoidosis and N=19 cases with eosinophilic myocarditis. A total of N=3,392 (42%) patients were found to have inflammatory heart disease such as inflammatory cardiomyopathy and borderline myocarditis, whereby a differentiation of the inflammatory infiltrates revealed considerable differences in the quality of inflammation. Viral genomes were found in the myocardium of N=6,072 (75%) patients, with treatment-relevant viral infections detected in N=2,015 (25%) cases. The remaining N=1,705 (21%) patients were diagnosed with other cardiomyopathies, including dilated cardiomyopathy (N=1,252), heart failure with preserved ejection fraction (N=325), hypertrophic cardiomyopathy (N=117) and arrhythmogenic right ventricular cardiomyopathy (N=11). Conclusions This retrospective study of over 8,000 patients with heart failure clearly shows that a definitive diagnosis is only possible with a comprehensive EMB diagnosis and leads to specific therapy in 79% of the cases. In the remaining 21% of patients, infectious and inflammatory causes could be excluded in order to initiate standard heart failure therapy. It is important to emphasize here that the quality of the inflammation and therapy-relevant viral infections cannot be detected with imaging techniques, which underlines the clinical-therapeutic importance of endomyocardial biopsy.

Background Despite progress in diagnosis and therapy of heart failure (HF), etiology and risk stratification remain elusive in many patients. Methods The My Biopsy HF Study (German clinical trials register number: DRKS22178) is a retrospective monocentric study investigating an all-comer population of patients with unexplained HF based on a thorough workup including endomyocardial biopsy (EMB). Results 655 patients (70.9% men, median age 55 [45/66] years) with non-ischemic, non-valvular HF were included in the analyses. 489 patients were diagnosed with HF with reduced ejection fraction (HFrEF), 52 patients with HF with mildly reduced ejection fraction (HFmrEF) and 114 patients with HF with preserved ejection fraction (HFpEF). After a median follow-up of 4.6 (2.5/6.6) years, 94 deaths were enumerated (HFrEF: 68; HFmrEF: 8; HFpEF: 18), equating to mortality rates of 3.3% and 11.6% for patients with HFrEF, 7.7% and 15.4% for patients with HFmrEF and 5.3% and 11.4% for patients with HFpEF after 1 and 5 years, respectively. In EMB, we detected a variety of putative etiologies of HF, including incidental cardiac amyloidosis (CA, 5.8%). In multivariate logistic regression analysis adjusting for age, sex and comorbidities only CA, age and NYHA functional class III + IV remained independently associated with all-cause mortality (CA: HR perui 3.13, 95% CI 1.5–6.51; p = 0.002). Conclusions In an all-comer population of patients presenting with HF of unknown etiology, incidental finding of CA stands out to be independently associated with all-cause mortality. Our findings suggest that prospective trials would be helpful to test the added value of a systematic and holistic work-up of HF of unknown etiology. Graphical abstract

Journal Article Endomyocardial biopsy in fulminant myocarditis: need for early and accurate diagnosis to improve the outcome Get access Heinz-Peter Schultheiss, Heinz-Peter Schultheiss Institute of Cardiac Diagnostics and Therapy, IKDT GmbH, Moltkestrasse 31, D-12203 Berlin, Germany Corresponding author. Tel: +49 30 84415550, Fax: +49 30 85525555, Email: heinz-peter.schultheiss@ikdt.de https://orcid.org/0000-0002-2185-3710 Search for other works by this author on: Oxford Academic PubMed Google Scholar Felicitas Escher Felicitas Escher Deutsches Herzzentrum der Charité, Department of Cardiology, Angiology and Intensive Care Medicine, Campus Virchow Klinikum, Berlin, GermanyDZHK (German Centre for Cardiovascular Research), Partner Site Berlin, Germany https://orcid.org/0000-0003-0678-5681 Search for other works by this author on: Oxford Academic PubMed Google Scholar European Heart Journal, Volume 44, Issue 48, 21 December 2023, Pages 5125–5127, https://doi.org/10.1093/eurheartj/ehad489 Published: 07 November 2023

Abstract Introduction Dilated cardiomyopathy (DCM) characterized by left ventricular dilation and impaired left ventricular function represents a common and severe cause of heart failure (HF). Predominantly affecting younger patients, it is considered a leading cause for sudden cardiac death and heart transplantation. Several studies identified myocarditis as a substantive precursor and potential cause of DCM. Inflammatory cardiomyopathy (DCMi) can lead to cardiomyocytal damage and exposure of cardiac myosin and other heart proteins. This cascade can in susceptible individuals trigger an altered immune response consecutively leading to autoimmunity and chronic inflammation. A variety of inflammatory and immunologic agents are discussed to be involved in the pathophysiology of myocardial inflammation. Several studies suggested a role of Interleukin -17 (IL-17) and Interferon-γ (IFN-γ) in chronic HF, myocardial infarction and other cardiovascular diseases. Underlying pathomechanisms, however, are poorly understood. Methods In this study we measured IL-17 and IFN-γ levels in serum by ELISA in patients in which an endomyocardial biopsy (EMB) was performed due to chronic unexplained heart failure symptoms after exclusion of ischemic or valvular heart disease at our center. All patients underwent transthoracic echocardiography prior to EMB sampling. Patients were classified according to the histological presence of inflammation into DCMi, DCM and patients with preserved left ventricular ejection fraction (LVEF) without inflammation. EMB specimens were analyzed including histology, immunohistochemistry and molecular virology. Results A total of 289 patients were included into the final analysis. Mean age was 47 years and 71% were male. Mean LVEF was 50% and mean left ventricular end-diastolic diameter (LVEDD) was 57 mm. Based on EMB results, 71 (25%) samples were categorized as DCMi and 113 (39%) as DCM. 105 (36%) samples were assigned to the group without myocardial inflammation and normal LVEF. The groups differed significantly in their inflammatory profiles. Levels of IL-17 (p < 0.001) and IFN-γ (p < 0.01) were significantly higher in patients with DCMi compared to the DCM as well as the normal LVEF group (Figure 1, Figure 2). Therefore, this effect is not specific for heart failure, but seems to be an important mediator in inflammatory cardiomyopathy. Conclusion Our data showed a significant elevation of IL-17 and IFN-γ in patients with inflammatory dilated cardiomyopathy. These findings suggest that these agents play an important role in the disease entity development and progression that remains poorly understood. So far treatment strategies in DCMi are unspecific. Therefore, blocking IL-17 expression could be an interesting potential therapeutic target in future (personalized) treatment for a wide group of patients with heart failure generated by inflammatory causes.Serum IL-17 levels.t-SNE analysis of the different groups.

OBJECTIVE:Inflammatory cardiomyopathy is characterised by inflammatory infiltrates leading to cardiac injury, left ventricular (LV) dilatation and reduced LV ejection fraction (LVEF). Several viral pathogens and autoimmune phenomena may cause cardiac inflammation.The effects of the gain of function FOXO3A single-nucleotide polymorphism (SNP) rs12212067 on inflammation and outcome were studied in a cohort of patients with inflammatory dilated cardiomyopathy (DCMi) in relation to cardiac viral presence.METHODS:Distribution of the SNP was determined in virus-positive and virus-negative DCMi patients and in control subjects without myocardial pathology. Baseline and outcome data were compared in 221 virus-negative patients with detection of cardiac inflammation and reduced LVEF according to their carrier status of the SNP.RESULTS:Distribution of SNP rs12212067 did not differ between virus-positive (n=22, 19.3%), virus-negative (n=45, 20.4 %) and control patients (n=18, 23.4 %), indicating the absence of susceptibility for viral infection or inflammation per se (p=0.199). Patients in the virus-negative DCMi group were characterised by reduced LVEF 35.5% (95% CI) 33.5 to 37.4) and increased LVEDD (LV end-diastolic diameter) 59.8 mm (95% CI 58.5 to 61.2). Within the group, SNP and non-SNP carriers had similarly impaired LVEF 39.2% (95% CI 34.3% to 44.0%) vs 34.5% (95% CI 32.4 to 36.5), p=0.083, and increased LVEDD 58.9 mm (95% CI 56.3 to 61.5) vs 60.1 mm (95% CI 58.6 to 61.6), p=0.702, respectively. The number of inflammatory infiltrates was not different in both SNP groups at baseline. Outcome after 6 months showed a significant improvement in LVEF and clinical symptoms in SNP rs12212067 carriers 50.9% (95% CI 45.4 to 56.3) versus non-SNP carriers 41.7% (95% CI 39.2 to 44.2), p≤0.01. The improvement in clinical symptoms and LVEF was associated with a significant reduction in cardiac inflammation (ΔCD45RO+ p≤0.05; ΔMac-1+ p≤0.05; ΔLFA-1+ p≤0.01; ΔCD54+ p≤0.01) in the SNP cohort versus non-SNP cohort, respectively. Subgroup analyses identified ΔMac-1+, ΔLFA-1+, ΔCD3+ and Δperforin+ as predictors for improvement in cardiac function in SNP-positive patients.CONCLUSION:FOXO3A might act as modulator of the cardiac immune response, diminishing cardiac inflammation and injury in pathogen-negative DCMi.

Viral myocarditis is characterized by infiltration of mononuclear cells essential for virus elimination. GPR15 has been identified as a homing receptor for regulatory T cells in inflammatory intestine diseases, but its role in inflammatory heart diseases is still elusive. Here we show that GPR15 deficiency impairs coxsackievirus B3 elimination, leading to adverse cardiac remodeling and dysfunction. Delayed recruitment of regulatory T cells in GPR15-deficient mice was accompanied by prolonged persistence of cytotoxic and regulatory T cells. In addition, RNA sequencing revealed prolonged inflammatory response and altered chemotaxis in knockout mice. In line, we identified GPR15 and its ligand GPR15L as an important chemokine receptor–ligand pair for the recruitment of regulatory and cytotoxic T cells. In summary, the insufficient virus elimination might be caused by a delayed recruitment of T cells as well as delayed interferon-γ expression, resulting in a prolonged inflammatory response and an adverse outcome in GPR15-deficient mice.