Role of immunosuppression in patients with lymphocytic myocarditis and myocardial parvovirus B19 with or without human herpesvirus 6 co-presence

Background

Parvovirus B19 (B19V) and Human Herpesvirus 6 (HHV6) are commonly detected in endomyocardial biopsy (EMB) specimens of patients with myocarditis symptoms. Whether B19V- and HHV6-DNA belong to the cardiac bio-portfolio remains unclear [1,2]. Until today, the role of B19V-/HHV6-DNA presence in myocarditis is doubtful. Both viruses have been detected in the myocardium, even independent of cardiac inflammation. Yet, their contribution to myocarditis remains controversial. The European Society of Cardiology guidelines exclude the use of immunosuppression in patients with virus-associated myocarditis [3]. Whether myocarditis patients with the presence of B19V-DNA alone or with HHV6-DNA in EMB findings can be treated using immunosuppression, remains a delicate question for clinicians.

Methods

931 patients with unexplained heart failure symptoms underwent EMB investigation to determine the underlying cause. Patients with low-levels (<1000 copies/μg DNA) of B19V-DNA and HHV6-DNA were identified. A sub-cohort of 28 patients who suffered from chronic-persistent lymphocytic myocarditis with ongoing symptoms was treated with azathioprine 100 mg once daily and prednisolone 1 mg/kg/day tapered down by 10 mg every two weeks followed by a second EMB. Twenty out of 28 patients had B19V-DNA only (mean LVEF=38%, age=47±15) and eight patients had B19V-/HHV6-DNA copresence (mean LVEF=39%, age=42±10). Patients with systemic infections were excluded. Both cohorts received standard heart failure medications. Continuous variables are expressed as mean±SD.

Results

B19V-DNA alone and in the presence of HHV6-DNA was detectable in the EMB of 377 and 63 patients, respectively. Following the immunosuppression course, the patients with B19V-DNA only and those with B19V-/HHV6-DNA showed complete resolution of inflammation in 12/20 and 5/8 patients, New York Heart Association (NYHA) functional class improvement in 9/20 and 4/8 patients, LVEF improvement by 8.0±13.8% (p<0.05) and 8.4±9.6% (p<0.05), and a reduction of LVEDD by 3.8±6.1mm (p<0.05) and 1.0±7.7mm (p>0.05), respectively. Importantly, following immunosuppression B19V and HHV6-DNA copy numbers went down from 186±266 to 130±186 copies/μg DNA and from 71±141 to 58±143 copies/μg DNA, respectively.

Conclusion

Chronic lymphocytic myocarditis patients with persistent B19V-DNA even in co-presence of HHV6-DNA may benefit from combined immunosuppression therapy. The therapy is clinically effective and safe to reduce cardiac inflammation independent of B19V- and HHV6-DNA copy numbers. In conclusion, we show for the first time that cases with chronic lymphocytic myocarditis can be principally treated with immunosuppression, despite B19V-/HHV6-DNA EMB presence.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): Berlin Institute of Health-Center for Regenerative Therapies

GPR15-mediated T cell recruitment during acute viral myocarditis is associated with improved virus elimination and outcome

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): DZHK

Ernst und Berta Grimmke Stiftung

Background

Myocarditis is an inflammatory disease of the myocardium indicated by mononuclear cell infiltration. It is predominantly caused by infectious agents such as coxsackievirus B3 (CVB3). Especially in young adults, myocarditis is a major source of sudden cardiac arrest. However, its clinical course has a broad spectrum of outcomes, ranging from mild symptoms and complete recovery to cardiac dysfunction and dilated cardiomyopathy. G protein-coupled receptor 15 (GPR15) was identified as a T cell homing receptor in the context of inflammatory intestine and skin diseases. We found Gpr15 to be highly upregulated in the left ventricle (LV) 7 days after CVB3 infection in wild type (WT) mice.

Purpose

GPR15 has not been described in a cardiac context, yet. Our aim was to investigate the role of GPR15 in recruiting immune cell subsets and later in virus elimination during viral myocarditis.

Methods

Gpr15 deficient (Gpr15gfp/gfp) and WT mice were infected intraperitoneal with CVB3 to investigate the acute (6 & 7 days post infection(p.i.)) and the subacute phase (16 days p.i.) of myocarditis. To study differentially expressed genes, LV tissue was used for TaqMan analysis and RNA-sequencing. Inflammation and fibrosis were evaluated on histological level. For functional characterization, healthy and diseased mice were hemodynamically characterized 16 days p.i.. Furthermore, in vitro migration assays were used to study the interaction between GPR15 and its ligands in vitro.

Results

Infected Gpr15gfp/gfp mice exhibited higher upregulation of immune response related genes on mRNA level in the acute phase of myocarditis 7 days p.i.. For instance, Cd8a, a cytotoxic T cell marker, and Foxp3, a regulatory T cell marker, were significantly higher in infected Gpr15gfp/gfp compared to infected WT mice. Bulk RNA-sequencing confirmed that the response to virus did not decline from day 6 to 7 in infected GPR15-deficient mice as observed in infected WT mice. Subsequent gene ontology (GO) term analyses reveled enhanced chemotaxis and cytotoxic T cell-related GO terms in GPR15-deficient mice on day 7.

Among investigated T cell subsets, GPR15 was highest expressed on CD8+ T cell. Its deficiency abolished chemotaxis of T cells, especially of cytotoxic T cells, towards GPR15 ligand in vitro.

In the subacute phase of myocarditis 16 days p.i., viral persistence was observed in more than 85 % of Gpr15gfp/gfp mice. In contrast, more than 70 % of WT mice with verified viremia cleared the virus successfully. Furthermore, Gpr15gfp/gfp mice demonstrated a decreased cardiac function accompanied by increased fibrosis in comparison to WT mice.

Conclusion

Our findings indicate that despite the prolonged inflammatory response, scant virus elimination was presumably caused by decelerated recruitment of cytotoxic T cells leading to impaired outcome in the GPR15-deficient mice.

[Update on collaborative autopsy-based research in German pathology, neuropathology, and forensic medicine]

BACKGROUND

Autopsies are a valuable tool for understanding disease, including COVID-19.

MATERIALS AND METHODS

The German Registry of COVID-19 Autopsies (DeRegCOVID), established in April 2020, serves as the electronic backbone of the National Autopsy Network (NATON), launched in early 2022 following DEFEAT PANDEMIcs.

RESULTS

The NATON consortium's interconnected, collaborative autopsy research is enabled by an unprecedented collaboration of 138 individuals at more than 35 German university and non-university autopsy centers through which pathology, neuropathology, and forensic medicine autopsy data including data on biomaterials are collected in DeRegCOVID and tissue-based research and methods development are conducted. More than 145 publications have now emerged from participating autopsy centers, highlighting various basic science and clinical aspects of COVID-19, such as thromboembolic events, organ tropism, SARS-CoV‑2 detection methods, and infectivity of SARS-CoV-2 at autopsy.

CONCLUSIONS

Participating centers have demonstrated the high value of autopsy and autopsy-derived data and biomaterials to modern medicine. The planned long-term continuation and further development of the registry and network, as well as the open and participatory design, will allow the involvement of all interested partners.

A novel class of small tRNA-like noncoding transcripts arising from the human NEAT1-MALAT1 region critically influences innate immunity and angiogenesis

Background

The evolutionary conserved NEAT1-MALAT1 gene cluster encounters high interest in cardiovascular medicine and oncology. The cluster generates large primary transcripts which remain nuclear, whereas novel tRNA-like transcripts (mascRNA, menRNA) enzymatically generated from these precursors translocate to the cytosol. We previously found that NEAT1 and MALAT1 deficient mice display accelerated atherosclerosis and vascular inflammation due to immune dysfunctions.

Methods

While the previously investigated mice were deficient in the entire NEAT1 or MALAT1 locus, here we aimed to selectively disrupt only tRNA-like transcripts “menRNA” arising from NEAT1, or “mascRNA” arising from MALAT1. To none of these a biological function has been assigned so far. Both lncRNAs give rise to transcripts of vastly different size (NEAT1: 23kb MENb, 3.7kb MENe, 59nt “menRNA”; MALAT1: 8.3 kb primary, 59nt “mascRNA”), and traditional knockout methods are unable to selectively inactivate one of the small transcripts only. Through CRISPR/Cas9 editing we therefore developed human monocyte-macrophage cell lines with short deletions in the respective tRNA-encoding sequences to disrupt normal menRNA or mascRNA formation, respectively. These editing procedures do not affect transcription of the respective lncRNA parent transcripts, and also not disturb regular formation of the triple-helix structures at their 3'-ends which support stabilization of the respective lncRNAs (Fig. 1).

Results

We found the tRNA-like transcripts menRNA and mascRNA critically influence innate immunity and angiogenesis. In addition to common anomalies resulting from their selective CRISPR-Cas9 mediated deletion (Fig. 1), there are specific disturbances associated with either Δmasc or Δmen cells (Fig. 2).

Both ΔmascRNA and ΔmenRNA human monocytes show profoundly altered ribosomal RNA/protein and tRNA-modifying enzyme expression, display anomalous growth/ angiogenetic factor expression, fundamentally change angiogenetic patterns in co-cultures with human endothelial cells, and have gravely disturbed innate immune responses (LPS, DNA and RNA viruses) (Fig. 1).

CRISPR-engineered ΔmenRNA cells share remakable similarities with human post-MI PBMCs, suggesting the NEAT1-menRNA system may significantly contribute to post-MI residual inflammatory risk despite optimal standard therapy (Fig. 2).

Conclusions

Beyond prior work in knockout mice documenting immune function of the NEAT1-MALAT1 cluster, the current study identifies menRNA and mascRNA as important novel components of human innate immunity with relevance for angiogenetic processes. These data provide a second mechanistic link for the apparent relevance of the NEAT1-MALAT1 gene cluster in cardiovascular and malignant diseases. As prototypes of a novel class of small noncoding RNAs (distinct from miRNAs and siRNAs) they may constitute cytosolic therapeutic targets.

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): DZHK Shared Expertise Project/B19-006_SE/FKZ 81X2100257/Transcriptome analysis of circulating immune cells to improve the assessment of prognosis and the response to novel anti-inflammatory treatments after myocardial infarction Figure 1. Common anomaliesFigure 2. Specific anomalies

Value of cardiac magnetic resonance imaging derived spectral myocardial strain pattern for non-invasive diagnosis of myocarditis

Funding Acknowledgements

Type of funding sources: Public grant(s) – EU funding. Main funding source(s): European Society of Radiology European Institute for Biomedical Imaging Research

Background

Traditionally, cardiac function is quantified by measures of peak excursion, for example ejection fraction. However, myocardial strain estimation from cine- cardiac MRI allows quantification of cardiac motion over the whole heart cycle. We propose a spectral decomposition of the strain curves applying Discrete Fourier transformation (DFT).

Purpose

To evaluate a potential additive diagnostic value of spectral temporal strain curve quantification for non-invasive diagnosis of myocarditis using cardiac MRI.

Methods

In the single-center prospective study patients with suspected myocarditis underwent comprehensive cardiac MRI followed by biventricular endomyocardial biopsy (EMB) between 2012 and 2014. DFT was applied to myocardial strain curves extracted from cine-Images. As reference model, a L1- and L2-penalized logistic regression model using global native T1 time, T2 time and presence of late-gadolinium enhancement was trained to predict EMB results and compared to two models which additionally include three orders of DFT coefficients and ejection fraction, respectively. Predictive performance was evaluated in a tournament-leave-pair-out cross-validation approach with a bootstrap correction for testing of multiple hyperparameter configurations.

Results

Out of 100 patients (28 % female, median age 40 [IQR 32 to 56) years) with acute symptom-onset (<30 days) 65 had pathologically proven myocarditis in EMB. The DFT model showed best discrimination (Area under the receiver-operating-curve [AUC] 0.72 [95% CI 52 to 87]). Addition of ejection fraction (AUC 0.60 [95% CI: 0.43 to 0.74]) did not increase AUC compared to the reference (AUC 0.60 [95% CI: 0.43 to 0.74]). Posterior distribution of the bootstrap-corrected AUC difference between DFT and reference model was gaussian (mean 12%, standard deviation 12%) with a posterior probability of 86%, that DFT has a greater AUC.

Conclusions

Discrimination of myocarditis from similar clinical presentations remains challenging. The results support incremental discriminatory value of DFT-decomposed myocardial strain for non-invasive diagnosis of myocarditis. Future research should address the value of the spectral decomposition of cardiac motion trajectories in larger samples and different disease entities.

Cardiac MRI findings to differentiate athlete's heart from hypertrophic (HCM), arrhythmogenic right ventricular (ARVC) and dilated (DCM) cardiomyopathy

To provide clinically relevant criteria for differentiation between the athlete’s heart and similar appearing hypertrophic (HCM), dilated (DCM), and arrhythmogenic right-ventricular cardiomyopathy (ARVC) in MRI. 40 top-level athletes were prospectively examined with cardiac MR (CMR) in two university centres and compared to retrospectively recruited patients diagnosed with HCM (n = 14), ARVC (n = 18), and DCM (n = 48). Analysed MR imaging parameters in the whole study cohort included morphology, functional parameters and late gadolinium enhancement (LGE). Mean left-ventricular enddiastolic volume index (LVEDVI) was high in athletes (105 ml/m²) but significantly lower compared to DCM (132 ml/m²; p = 0.001). Mean LV ejection fraction (EF) was 61% in athletes, below normal in 7 (18%) athletes vs. EF 29% in DCM, below normal in 46 (96%) patients (p < 0.0001). Mean RV-EF was 54% in athletes vs. 60% in HCM, 46% in ARVC, and 41% in DCM (p < 0.0001). Mean interventricular myocardial thickness was 10 mm in athletes vs. 12 mm in HCM (p = 0.0005), 9 mm in ARVC, and 9 mm in DCM. LGE was present in 1 (5%) athlete, 8 (57%) HCM, 10 (56%) ARVC, and 21 (44%) DCM patients (p < 0.0001). Healthy athletes’ hearts are characterized by both hypertrophy and dilation, low EF of both ventricles at rest, and increased interventricular septal thickness with a low prevalence of LGE. Differentiation of athlete’s heart from other non-ischemic cardiomyopathies in MRI can be challenging due to a significant overlap of characteristics also seen in HCM, ARVC, and DCM.

Diagnosis and treatment of cardiac amyloidosis: position statement of the German Cardiac Society (DGK)

Systemic forms of amyloidosis affecting the heart are mostly light-chain (AL) and transthyretin (ATTR) amyloidoses. The latter is caused by deposition of misfolded transthyretin, either in wild-type (ATTRwt) or mutant (ATTRv) conformation. For diagnostics, specific serum biomarkers and modern non-invasive imaging techniques, such as cardiovascular magnetic resonance imaging (CMR) and scintigraphic methods, are available today. These imaging techniques do not only complement conventional echocardiography, but also allow for accurate assessment of the extent of cardiac involvement, in addition to diagnosing cardiac amyloidosis. Endomyocardial biopsy still plays a major role in the histopathological diagnosis and subtyping of cardiac amyloidosis. The main objective of the diagnostic algorithm outlined in this position statement is to detect cardiac amyloidosis as reliably and early as possible, to accurately determine its extent, and to reliably identify the underlying subtype of amyloidosis, thereby enabling subsequent targeted treatment.

Mechanisms of angina in patients with biopsy-proven viral myocarditis: insights from intracoronary acetylcholine testing

Background

Patients with myocarditis often present with angina pectoris despite unobstructed coronary arteries. The underlying pathophysiological mechanism of angina in these patients remains to be elucidated. Coronary artery spasm is a well-known cause of angina in patients with unobstructed coronary arteries. In this study, we sought to assess the frequency of coronary vasomotor disorders in patients with biopsy-proven viral myocarditis.

Methods

In total, 700 consecutive patients who underwent endomyocardial biopsy for suspected myocarditis between 2008 and 2018 were retrospectively screened. Of these patients, viral myocarditis was confirmed in 303 patients defined as histological/immunohistological evidence of myocardial inflammation and presence of viral genome confirmed by PCR. Of these patients, 34 patients had angina despite unobstructed coronary arteries and underwent intracoronary acetylcholine (ACh) provocation testing in search of coronary spasm. Epicardial spasm was defined as acetylcholine-induced reproduction of the patient's symptoms associated with ischemic ECG changes and &gt;90% epicardial vasoconstriction. Microvascular spasm was defined as symptom reproduction and ECG changes in the absence of significant epicardial vasoconstriction.

Results

Patients were 49±16 years old, 62% were male and left ventricular ejection fraction was 54±16%. Most frequent viruses were parvovirus B19 (PVB19, 59%) and human herpes virus 6 (HHV6, 26%), 2 patients had combined PVB19/HHV6 infection and 3 patients other herpesviruses (CMV, EBV, VZV). Epicardial spasm was observed in 10 patients (29%) during ACh testing and microvascular spasm was found in 11 patients (32%). The rate of coronary spasm (epicardial and microvascular) was higher in the PVB19 subgroup compared to HHV6 (80% vs. 33%, p=0.031). In particular, there was a higher prevalence of microvascular spasm in PVB19 compared to HHV6 (45% vs. 0%, p=0.018).

Conclusion

We observed a high prevalence of microvascular and epicardial spasm in patients with biopsy-proven viral myocarditis suggesting coronary spasm as a potential underlying mechanism for angina in these patients. Microvascular spasm was most often observed in patients with PVB19-associated myocarditis.

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): Robert-Bosch-Stiftung; Berthold-Leibinger-Stiftung

4323Detection of early inflammation in myocarditis by molecular magnetic resonance imaging of activated platelets

Introduction

A noninvasive imaging strategy for diagnosis and localization of early myocarditis would be of great clinical interest. However, resolution of current imaging techniques is limited. Platelets play an important role in inflammatory processes but the role in myocarditis is unknown. Therefore, the aim of this project was to examine the role of platelets in myocarditis and establish a sensitive non-invasive molecular MRI in-vivo imaging strategy for diagnosis of myocarditis with a contrast agent against activated platelets in mice.

Methods

Myocarditis was induced by subcutaneous injection of an emulsion of porcine cardiac myosin and complete freud's adjuvant (CFA) in Balb/c mice. Inflammatory activity was targeted with a contrast agent against activated platelets consisting of microparticles of iron oxide (MPIO) conjugated to a single chain antibody directed against ligand-induced binding sites (LIBS) on activated glycoprotein IIb/IIIa (=LIBS-MPIO). In comparison, we applied an unspecific control antibody linked to microparticles of iron oxide (control-MPIO) and injected LIBS-MPIO to mice subjected to incomplete freud's adjuvant (iCFA). All imaging results were correlated to immunohistochemistry findings.

Results

Histological evaluation showed significantly higher binding of LIBS-MPIOs to platelet enriched, CD41-positive inflamed myocardium two days after induction of myocarditis in comparison to later time points (7d, 14d, 21d) (p<0.05) and control-MPIO (p<0.05) injection. In iCFA injected mice no significant LIBS-MPIO binding was found (p<0.05). In 3D in-vivo MRI we could specifically detect focal signal effects in LIBS-MPIO injected mice 2 days after induction of myocarditis, whereas in control-MPIO injected mice no signal effect was visible. Quantification of the myocardial MRI signal confirmed a signal decrease after LIBS-MPIO injection and significant fewer signals in comparison to control-MPIO injection (p<0.05).

As a perspective, we also found CD41 positive areas in histology of human myocarditis specimens.

Conclusions

Platelets are involved in the inflammation of myocarditis. Molecular MRI with LIBS-MPIO can image them at an early time point. This noninvasive imaging strategy is of clinical interest for both diagnostic and prognostic purposes, and highlights the potential of molecular MRI for characterization of cardiovascular pathologies such as myocardial inflammation.

P3688Familial recurrent autoimmune myocarditis associated with a truncating nonsense mutation of the desmoplakin gene

Background

Arrhythmogenic cardiomyopathy (AC) is an important cause of ventricular arrhythmias in children and young adults. AC is associated with mutation of desmosomal proteins, however, cardiac disease penetrance is incomplete and the clinical course varies widely without recognizable exogenous or epi/genetic co-factors. Importantly, DSP mutation carriers may also display entirely non-cardiac e.g. dermatological phenotypes.

Methods and results

In two brothers with recurrent fulminant myocarditis, mutation screening of 218 cardiomyopathy-related genes identified a truncating mutation Arg1458* of desmoplakin (DSP). DSP immunhistology unexpectedly revealed complete loss (“knockout”) of DSP protein in endomyocardial biopsies (EMBs), but none of the histological anomalies of AC. Criteria for histological diagnosis of myocarditis were not either fulfilled, and cardiac MRI revealed no features associated with AC. Screening for infections was negative, there was no substance abuse, medication or vaccination. Possible disease triggers were competitive sport events. Myosin and troponin I autoantibodies were detected at titers up to 1:320.

We used allele-specific RT-PCR to distinguish if the patients' allele classified as “normal” was actually defective due to promotor mutation or epigenetic silencing. RT-PCRs were done on EMBs and peripheral blood mononuclear cells (PBMCs). In a cohort of dilated cardiomyopathy (DCM) patients we were able to detect DSP transcripts in both, PBMC and left-ventricular heart tissue. RNA sequencing of human PBMC subpopulations suggested that DSP transcription may be restricted to certain immune cell subtypes. RT-PCRs revealed that both Arg1458* carriers have a functional second DSP allele, indicating that their “DSP knockout” occurs at the protein level and may be due to protein instability and degradation within desmosomes.

We screened additional existing cohorts for such variants and identified stopgain variant Gln307Ter in a 37-yrs-old woman with ARVC. This patient's sister died from heart failure at the age of 39. In a 59-yrs-old female LVNC patient, stopgain variant Y1391X was identified. Here, family history was unclear, her brother probably died from coronary artery disease. In a 71-yrs-old female DCM patient with no family history, stopgain variant Tyr1512Ter was identified.

Conclusions

The described patients with DSP truncations strongly suggest the existence of additional genetic or exogenous modifiers driving pathogenesis either way. DSP defects may cause recurrent myocarditis, and mutation screening is advisable to enable early detection of high-risk patients with similar phenotypes. Our finding of complete myocardial DSP protein loss emphasizes that DNA sequencing may miss critical molecular disturbances. It is indispensable to also analyze transcriptome and protein level in the tissue actually affected in a patient in order to recognize his/her individual pathogenesis.

5035Comparative assessment of diagnostic algorithms of myocardial inflammation by endomyocardial biopsy and tissue mapping by CMR against high-sensitive troponin in viral myocarditis

Background

Myocarditis is defined by inflammatory involvement of the myocardium, either histologically by evidence of myocardial necrosis and cellular infiltration on endomyocardial biopsy (EMB), or non-invasively by presence of myocardial oedema using tissue mapping with cardiovascular magnetic resonance (CMR). Objective: to undertake intra-individual comparisons of EMB vs. CMR diagnostic algorithms of myocardial inflammation, as well as against an independent gold-standard of myocardial injury, high-sensitive troponin (hs-TropT).

Methods

Prospective multicentre study of consecutive patients (n=109) with clinical diagnosis of myocarditis. EMBs were analysed by 2 reference centres using the ESC diagnostic and their local algorithms. The CMR criteria used sequence-specific cut-offs for native T1 and T2 (standard deviation, SD); myocardial inflammation T1 ≥2SD, T2 ≥2SD and no inflammation: T1 and T2<2SD, with subcategories for acute/high-grade: T1 ≥5SD, T2 ≥2SD; chronic/low-grade: T1 ≥2SD, T2 ≥2SD; healed: T1 <2SD, T2 <2SD but myocardial impairment and non-inflammatory cardiomyopathy: T1 ≥2SD, T2 <2SD.

Results

The agreement between ESC criteria and CMR criteria (AUC: 0.56, p=0.381) was poor. There was a significant agreement between myocardial injury (hs-TropT ≥13.9 ng/L) and CMR criteria (AUC: 0.84, p<0.001), but not ESC algorithm. hs-TropT levels had significant associations with native T1 and T2 (r=0.37 and 0.35, p<0.001), but not with immunohistochemical inflammatory markers. Viral presence was similarly proportioned between inflammatory/non-inflammatory subjects, irrespective of the algorithm.

AUC of CMR and EMB versus hs-TroponinT

Conclusions

Poor agreement between CMR and EMB-based diagnostic algorithms suggests non-overlapping definitions of myocardial inflammatory involvement. Excellent agreement between CMR algorithm and hs-TropT reiterates its high sensitivity for inflammatory myocardial injury.

Acknowledgement/Funding

1. National Institute for Health Research (NIHR) Biomedical Research Centre 2. German Centre for Cardiovascular Research (DZHK)

P1614Soluble guanylate cyclase as a therapeutic target in heart failure: myocardial gene expression in response to sGC stimulation in pressure overload

Background

Heart Failure (HF) is associated with endothelial dysfunction and reduced bioavailability of NO with insufficient stimulation of sGC and reduced production of cGMP. Therefore, the impairment of the NO-sGC-cGMP pathway results in vasoconstriction, platelet aggregation, inflammation, fibrosis and most importantly maladaptive cardiac hypertrophy. The restoration of the NO-sGC -cGMP pathway is an attractive pharmacological target for HF therapy.

Purpose

Riociguat is an NO independent stimulator of the sGC that sensitizes the sGC to endogenous NO and directly stimulates sGC to produce cGMP. We therefore hypothesized that Riociguat prevents pathological effects occurring during HF.

Methods

Pressure overload was induced by transverse aortic constriction (TAC) in 8 weeks old male C57Bl6/N mice. Three weeks after TAC when cardiac hypertrophy has developed either Riociguat (RIO; 3 mg/kg) or a Solvent was administered daily for 5 more weeks (n=12 per group). Animals with sham surgery and same drug regime served as controls. The heart function in all groups was evaluated weekly by small animal echocardiography. Eight weeks after surgery, the transcriptome of the left ventricles (LV) of sham and TAC mice were analysed by RNA Sequencing. Differentially expressed genes (DEG) were categorised using Ingenuity Pathway Analysis (IPA).

Results

TAC resulted in a steady decrease of left ventricular fractional shortening (FS) in the mice until week 3. When Riociguat treatment commenced, the systolic LV function of the TAC+Rio group recovered significantly whereas the solvent group showed a further decline until week 8 (FS 21.4±3.4% vs. 9.5±2%, p<0.001). Both sham groups (Sham+Sol and Sham+Rio) showed no changes in the heart function over timer. Regarding the hypertrophic response to LV pressure overload, Riociguat treatment attenuated significantly the increase of the left ventricular mass (LVM 208.3±15.8mg vs. 148.9±11.8mg, p<0.001) after TAC. In line with the reduced LVM, histological staining showed a significantly reduced fibrosis and myocyte cross sectional area in the TAC+Rio group compared to TAC+Sol group. Regarding the myocardial transcriptome, the treatment with Riociguat resulted in less changes of gene expression pattern after TAC (TAC+Sol vs. Sham+Sol 3160 DEG; TAC+Rio vs. Sham+Rio 2237 DEG). The expression of heart failure marker genes like ANP (Nppa), BNP (Nppb), β-Myosin Heavy Chain (Myh7) and the Collagens 1 and 3 (Col1a1, Col1a2, Col3a1) were significantly decreased in TAC+Rio, when compared to TAC+Sol. IPA analysis revealed that the activation of biological pathways in response to TAC, like actin cytoskeleton- and Integrin signalling, renin-angiotensin or cardiac hypertrophy signalling was attenuated when Riociguat was administered.

Conclusion

Riociguat attenuates pressure overload induced LV remodelling resulting in less hypertrophy, improved heart function and less alteration of gene expression pattern.

2424Long-term outcome of patients with biopsy-proven viral myocarditis: 12-year results from a late gadolinium enhancement cardiac magnetic resonance study

Purpose

Myocarditis is a common cardiac disease that is associated with significant mortality as demonstrated by several studies. Late gadolinium enhancement (LGE) by cardiac magnetic resonance imaging (CMR) is a valuable tool for risk stratification of patients with suspected myocarditis. Previous studies using CMR-LGE have reported a good negative predictive value over follow-up periods of 4–6 years, while its positive predictive value was only modest. However, there is a lack of data regarding the long-term prognosis (>10 years) of these patients. This study reports an extended long-term follow-up of a large cohort of patients with biopsy-proven viral myocarditis.

Methods

At initial presentation, all patients underwent endomyocardial biopsy and CMR for the work-up of suspected myocarditis or unclear cardiomyopathy and had evidence of virus in PCR analyses. The primary endpoints were: all-cause death, cardiac death, and the occurrence of sudden cardiac death (SCD).

Results

183 patients with biopsy-proven viral myocarditis were followed for a median of 11.5 years. At baseline, patients were 52 years old, 31% were females, and the median ejection fraction was moderately reduced (44%). Initial CMR assessment revealed LGE in 101 (55%) patients, while 82 (45%) patients had LGE-negative CMR. During the follow-up period, the following endpoints occurred in the overall cohort: all-cause death (n=71, 39%), cardiac death (n=50, 27%) and SCD (n=20, 11%). Most importantly, only a single LGE-negative patient experienced a SCD during this 12-year follow-up, while all other SCDs occurred in patients with LGE-positive CMR (1% vs. 19%, p<0.001). Consequently, the negative predictive value (NPV) of normal CMR-LGE regarding SCD was 98%. In addition, cardiac mortality (12% vs. 40%, p<0.001, NPV=88%) and all-cause mortality (20% vs. 54%, p<0.001, NPV=79%) were significantly lower in patients without LGE.

Conclusion

This cohort of biopsy-proven viral myocarditis demonstrates substantial mortality (39% in 11.5 years). However, absence of LGE on CMR was associated with favorable prognosis. This was applicable regarding all-cause and cardiac mortality, but most importantly with regard to SCD with a NPV of 98% over almost 12 years median follow-up.

Acknowledgement/Funding

This work was funded by the Robert-Bosch-Stiftung, Stuttgart, Germany and the Berthold-Leibinger-Stiftung, Ditzingen, Germany.

[Fatigue, breathlessness and chest pain in a 31-year-old man with schizoaffective disorder]

BACKGROUND

Clozapine is an alternative antipsychotic medication used to control symptoms of schizophrenia and to reduce risks of suicidal behavior in patients who did not adequately respond to standard medication. Due to severe side effects including cardiomyopathy and myocarditis its clinical use is limited.

CASE REPORT

A 31-year-old man of east European descent presented to the emergency medical department with fatigue, shortness of breath and chest pain. Due to a schizoaffective disorder he was treated with clozapine and lithium. Echocardiography revealed severely impaired left ventricular systolic function. After exclusion of coronary artery disease by coronary angiography an endomyocardial biopsy was performed according to the guidelines. This confirmed the clinically suspected toxic cardiomyopathy. Therefore, antipsychotic treatment was immediately changed and state of the art heart failure medication was started resulting in a clear improvement of left ventricular function.

CONCLUSION

In patients treated with clozapine or lithium and clinical signs of heart failure, toxic cardiomyopathy should be considered.

[Atrioventricular block and left ventricular wall mobility disorder in a 44-year-old female patient : A case report of a rarity with pitfalls]

Eosinophilic myocarditis is a rare condition with good treatment options, which can be difficult to diagnose. The clinical presentation can vary from asymptomatic to life-threatening forms. This article describes the case of a 44-year-old woman who suffered from vertigo, chest pain and dyspnea. The woman presented with an intermittent atrioventricular (AV) block II Mobitz type II° and mild impairment of left ventricular ejection fraction. Hypereosinophilia in the peripheral blood, cardiac magnetic resonance imaging (MRI) and endomyocardial biopsy led to the diagnosis of eosinophilic myocarditis, most likely as a result of an allergic reaction to Aspergillus fumigatus. A general treatment recommendation cannot be made due to the lack of evidence-based guidelines; however, recent scientific studies confirmed timely, high-dose steroid administration over several months to be the mainstay of treatment of eosinophilic myocarditis. The following article may be helpful in the early diagnosis and treatment of this underdiagnosed and insidious disease.

["Catecholamine refractory" cardiogenic shock? "Bridging-to-recovery" by implantation of a percutaneous cardiac assist device]

HISTORY AND ADMISSION FINDINGS

A 27-year-old man presented with acute dyspnea and a previous respiratory tract infection with progressive dyspnoea and chest pain over 2 weeks. Clinical findings revealed severe cardiac failure with development of cardiogenic shock and need for adrenergic drug therapy for circulatory support.

INVESTIGATIONS

The electrocardiogram showed a sinus tachycardia with unspecific T-wave-inversions, the echocardiogram revealed a dilated left ventricle and severely reduced systolic LV-function. An acute coronary syndrome could be excluded by coronary angiogram.

TREATMENT AND COURSE

A myocardial biopsy was taken to exclude giant cell myocarditis. The immediate initiation of a mechanical circulatory support by an Extracorporal Membrane Oxygenator (ECMO) facilitated rapid hemodynamic stabilization and recovery of organ function.

CONCLUSIONS

A drug-only circulatory support very often does not enable stabilization of a patient in progressive cardiogenic shock and cannot prevent multiorgan dysfunction. Therefore implantation of an assist device facilitates a "bridging-to-recovery" or a "bridging-to transplant" concept in critically ill patients presenting with cardiogenic shock. The bridging also allows for reviewing etiology and evaluation of further treatment options. In case of recovery continuous care in a specialized Heart Failure Clinic can help to maintain the clinical status and offer frequent reevaluation of cardiac status and therapeutic concepts.