Current treatment and immunomodulation strategies in Acute Myocarditis

Myocarditis is an inflammatory disease of the myocardium characterized by a great heterogeneity of presentation and evolution. Treatment of myocarditis is often supportive and the evidence for immunosuppression is scarce and debated. Conventional treatment is based on clinical presentation, ranging from conservative to advanced mechanical assist devices. In this setting, immunosuppression and immunomodulation therapies are mostly reserved for patients presenting with major clinical syndromes. In this review, we will summarise the current evidence and strategies for conventional and immunosuppressive treatments for patients presenting with acute myocarditis.

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

Hypertrophe Kardiomyopathien und die kardiale ATTR-Amyloidose – eine aktuelle Übersicht für den klinischen Alltag

Hypertrophe obstruktive Kardiomyopathie Mavacamten, der erste Myosin-Aktivator, konnte erfolgreich in dem EXPLORER-HCM-Studienprogramm getestet werden. Lebensqualität und linksventrikuläre Druckgradienten-Abnahme wurden optimiert. Ob damit jedoch auch die Überlebensrate und Prognose der betroffenen Patienten verbessert wird, kann bis heute noch nicht gesagt werden. Die europäischen Zulassungsbehörden sehen allerdings bisher die Ergebnisse als so bedeutsam an, dass mit einer Führung der Substanzklasse vielleicht schon in den nächsten 6–8 Monaten zu rechnen ist. In den USA ist die Substanz bereits seit April 2022 zugelassen. Der Einsatz der Substanz bei HCM-Patienten ohne Obstruktion wird ebenfalls zurzeit untersucht.

Kardiale Transthyretin-Amyloidosen Kardiale Amyloidosen haben meist eine gute Ejektionsfraktion, jedoch sind auch EF mit 40 oder < 30 % möglich. Das Auftreten einer kardialen Amyloidose bei Patienten mit der Symptomatik einer Herzinsuffizienz mit erhaltener Ejektionsfraktion (HFpEF) ist in bis zu 15 % der Fälle nachzuweisen. Tafamidis ist die einzige zurzeit zugelassene erfolgreiche Therapiemöglichkeit bei Patienten mit kardialer ATTR-Amyloidose. Dies wurde auch durch weitere Beobachtungsregister der ATTR-ACT-Studie gezeigt. Für die Klinik ist zusätzlich wichtig, dass die Amyloidose auch die Aortenklappe befällt. Zahlreiche Patienten entwickeln somit auch eine Aortenstenose, die erkannt und meist interventionell zu behandeln ist.

CMR findings after COVID-19 and after COVID-19-vaccination-same but different?

Cardiac involvement has been described in varying proportions of patients recovered from COVID-19 and proposed as a potential cause of prolonged symptoms, often described as post-COVID or long COVID syndrome. Recently, cardiac complications have been reported from COVID-19 vaccines as well. We aimed to compare CMR-findings in patients with clinical cardiac symptoms after COVID-19 and after vaccination. From May 2020 to May 2021, we included 104 patients with suspected cardiac involvement after COVID-19 who received a clinically indicated cardiac magnetic resonance (CMR) examination at a high-volume center. The mean time from first positive PCR to CMR was 112  ± 76 days. During their COVID-19 disease, 21% of patients required hospitalization, 17% supplemental oxygen and 7% mechanical ventilation. In 34 (32.7%) of patients, CMR provided a clinically relevant diagnosis: Isolated pericarditis in 10 (9.6%), %), acute myocarditis (both LLC) in 7 (6.7%), possible myocarditis (one LLC) in 5 (4.8%), ischemia in 4 (3.8%), recent infarction in 2 (1.9%), old infarction in 4 (3.8%), dilated cardiomyopathy in 3 (2.9%), hypertrophic cardiomyopathy in 2 (1.9%), aortic stenosis, pleural tumor and mitral valve prolapse each in 1 (1.0%). Between May 2021 and August 2021, we examined an additional 27 patients with suspected cardiac disease after COVID-19 vaccination. Of these, CMR provided at least one diagnosis in 22 (81.5%): Isolated pericarditis in 4 (14.8%), acute myocarditis in 9 (33.3%), possible myocarditis (acute or subsided) in 6 (22.2%), ischemia in 3 (37.5% out of 8 patients with stress test), isolated pericardial effusion (> 10 mm) and non-compaction-cardiomyopathy each in 1 (3.7%). The number of myocarditis diagnoses after COVID-19 was highly dependent on the stringency of the myocarditis criteria applied. When including only cases of matching edema and LGE and excluding findings in the right ventricular insertion site, the number of cases dropped from 7 to 2 while the number of cases after COVID-19 vaccination remained unchanged at 9. While myocarditis is an overall rare side effect after COVID-19 vaccination, it is currently the leading cause of myocarditis in our institution due to the large number of vaccinations applied over the last months. Contrary to myocarditis after vaccination, LGE and edema in myocarditis after COVID-19 often did not match or were confined to the RV-insertion site. Whether these cases truly represent myocarditis or a different pathological entity is to be determined in further studies.

Colchicine prevents disease progression in viral myocarditis via modulating the NLRP3 inflammasome in the cardiosplenic axis

Aim

The acute phase of a coxsackievirus 3 (CVB3)‐induced myocarditis involves direct toxic cardiac effects and the systemic activation of the immune system, including the cardiosplenic axis. Consequently, the nucleotide‐binding oligomerization domain‐like receptor pyrin domain‐containing‐3 (NLRP3) inflammasome pathway is activated, which plays a role in disease pathogenesis and progression. The anti‐inflammatory drug colchicine exerts its effects, in part, via reducing NLRP3 activity, and has been shown to improve several cardiac diseases, including acute coronary syndrome and pericarditis. The aim of the present study was to evaluate the potential of colchicine to improve experimental CVB3‐induced myocarditis.

Methods and results

C57BL6/j mice were intraperitoneally injected with 1 × 10⁵ plaque forming units of CVB3. After 24 h, mice were treated with colchicine (5 μmol/kg body weight) or phosphate‐buffered saline (PBS) via oral gavage (p.o.). Seven days post infection, cardiac function was haemodynamically characterized via conductance catheter measurements. Blood, the left ventricle (LV) and spleen were harvested for subsequent analyses. In vitro experiments on LV‐derived fibroblasts (FB) and HL‐1 cells were performed to further evaluate the anti‐(fibro)inflammatory and anti‐apoptotic effects of colchicine via gene expression analysis, Sirius Red assay, and flow cytometry. CVB3 + colchicine mice displayed improved LV function compared with CVB3 + PBS mice, paralleled by a 4.7‐fold (P < 0.01) and 1.7‐fold (P < 0.001) reduction in LV CVB3 gene expression and cardiac troponin‐I levels in the serum, respectively. Evaluation of components of the NLRP3 inflammasome revealed an increased percentage of apoptosis‐associated speck‐like protein containing a CARD domain (ASC)‐expressing, caspase‐1‐expressing, and interleukin‐1β‐expressing cells in the myocardium and in the spleen of CVB3 + PBS vs. control mice, which was reduced in CVB3 + colchicine compared with CVB3 + PBS mice. This was accompanied by 1.4‐fold (P < 0.0001), 1.7‐fold (P < 0.0001), and 1.7‐fold (P < 0.0001) lower numbers of cardiac dendritic cells, natural killer cells, and macrophages, respectively, in CVB3 + colchicine compared with CVB3 + PBS mice. A 1.9‐fold (P < 0.05) and 4.6‐fold (P < 0.001) reduced cardiac gene expression of the fibrotic markers, Col1a1 and lysyl oxidase, respectively, was detected in CVB3 + colchicine mice compared with CVB3 + PBS animals, and reflected by a 2.2‐fold (P < 0.05) decreased Collagen I/III protein ratio. Colchicine further reduced Col3a1 mRNA and collagen protein expression in CVB3‐infected FB and lowered apoptosis and viral progeny release in CVB3‐infected HL‐1 cells. In both CVB3 FB and HL‐1 cells, colchicine down‐regulated the NLRP3 inflammasome‐related components ASC, caspase‐1, and IL‐1β.

Conclusions

Colchicine improves LV function in CVB3‐induced myocarditis, involving a decrease in cardiac and splenic NLRP3 inflammasome activity, without exacerbation of CVB3 load.

The Spontaneous Course of Human Herpesvirus 6 DNA-Associated Myocarditis and the Effect of Immunosuppressive Intervention

Introduction: This study investigated the spontaneous clinical course of patients with endomyocardial biopsy (EMB)-proven lymphocytic myocarditis and cardiac human herpesvirus 6 (HHV6) DNA presence, and the effectiveness of steroid-based intervention in HHV6-positive patients. Results: 756 heart failure (HF) patients underwent an EMB procedure to determine the underlying cause of unexplained HF. Low levels of HHV6 DNA, detectable by nested PCR only, were found in 10.4% of the cases (n = 79) of which 62% (n = 49) showed myocardial inflammation. The spontaneous course of patients with EMB-proven HHV6 DNA-associated lymphocytic myocarditis (n = 26) showed significant improvements in the left ventricular ejection fraction (LVEF) and clinical symptoms, respectively, in 15/26 (60%) patients, 3–12 months after disease onset. EMB mRNA expression of components of the NLRP3 inflammasome pathway and protein analysis of cardiac remodeling markers, analyzed by real-time PCR and MALDI mass spectrometry, respectively, did not differ between HHV6-positive and -negative patients. In another cohort of patients with ongoing symptoms related to lymphocytic myocarditis associated with cardiac levels of HHV6-DNA copy numbers <500 copies/µg cardiac DNA, quantified by real-time PCR, the efficacy and safety of steroid-based immunosuppression for six months was investigated. Steroid-based immunosuppression improved the LVEF (≥5%) in 8/10 patients and reduced cardiac inflammation in 7/10 patients, without an increase in cardiac HHV6 DNA levels in follow-up EMBs. Conclusion: Low HHV6 DNA levels are frequently detected in the myocardium, independent of inflammation. In patients with lymphocytic myocarditis with low levels of HHV6 DNA, the spontaneous clinical improvement is nearby 60%. In selected symptomatic patients with cardiac HHV6 DNA copy numbers less than 500 copies/µg cardiac DNA and without signs of an active systemic HHV6 infection, steroid-based therapy was found to be effective and safe. This finding needs to be further confirmed in large, randomized trials.

An optimized imaging protocol for [99mTc]Tc-DPD scintigraphy and SPECT/CT quantification in cardiac transthyretin (ATTR) amyloidosis

BACKGROUND

In [99mTc]Tc-DPD scintigraphy for myocardial ATTR amyloidosis, planar images 3 hour p.i. and SPECT/CT acquisition in L-mode are recommended. This study investigated if earlier planar images (1 hour p.i.) are beneficial and if SPECT/CT acquisition should be preferred in H-mode (180° detector angle) or L-mode (90°).

METHODS

In SPECT/CT phantom measurements (NaI cameras, N = 2; CZT, N = 1), peak contrast recovery (CRpeak) was derived from sphere inserts or myocardial insert (cardiac phantom; signal-to-background ratio [SBR], 10:1 or 5:1). In 25 positive and 38 negative patients (reference: endomyocardial biopsy or clinical diagnosis), Perugini scores and heart-to-contralateral (H/CL) count ratios were derived from planar images 1 hour and 3 hour p.i.

RESULTS

In phantom measurements, accuracy of myocardial CRpeak at SBR 10:1 (H-mode, 0.95-0.99) and reproducibility at 5:1 (H-mode, 1.02-1.14) was comparable for H-mode and L-mode. However, L-mode showed higher variability of background counts and sphere CRpeak throughout the field of view than H-mode. In patients, sensitivity/specificity were ≥ 95% for H/CL ratios at both time points and visual scoring 3 hour. At 1 hour, visual scores showed specificity of 89% and reduced reader's confidence.

CONCLUSIONS

Early DPD images provided no additional value for visual scoring or H/CL ratios. In SPECT/CT, H-mode is preferred over L-mode, especially if quantification is applied apart from the myocardium.

Epicardial Fat Expansion in Diabetic and Obese Patients With Heart Failure and Preserved Ejection Fraction-A Specific HFpEF Phenotype

Heart failure with preserved ejection fraction (HFpEF) is a heterogeneous syndrome with diverse etiologies and pathophysiological factors. Obesity and type 2 diabetes mellitus (T2DM), conditions that coexist frequently, induce a cluster of metabolic and non-metabolic signaling derangements which are in favor to induce inflammation, fibrosis, myocyte stiffness, all hallmarks of HFpEF. In contrast to other HFpEF risk factors, obesity and T2DM are often associated with the generation of enlarged epicardial adipose tissue (EAT). EAT acts as an endocrine tissue that may exacerbate myocardial inflammation and fibrosis via various paracrine and vasocrine signals. In addition, an abnormally large EAT poses mechanical stress on the heart via pericardial restrain. HFpEF patients with enlarged EAT may belong to a unique phenotype that can benefit from specific EAT-targeted interventions, including life-style modifications and pharmacologically via statins and fat modifying anti-diabetics drugs; like metformin, sodium-glucose cotransporter 2 inhibitors, or glucagon-like peptide-1 receptor agonists, respectively.

Modulation of the acute defence reaction by eplerenone prevents cardiac disease progression in viral myocarditis

Aims

Left ventricular (LV) dysfunction in viral myocarditis is attributed to myocardial inflammation and fibrosis, inducing acute and long‐time cardiac damage. Interventions are not established. On the basis of the link between inflammation, fibrosis, aldosterone, and extracellular matrix regulation, we aimed to investigate the effect of an early intervention with the mineralocorticoid receptor antagonist (MRA) eplerenone on cardiac remodelling in a murine model of persistent coxsackievirus B3 (CVB3)‐induced myocarditis.

Methods and results

SWR/J mice were infected with 5 × 10⁴ plaque‐forming units of CVB3 (Nancy strain) and daily treated either with eplerenone (200 mg/kg body weight) or with placebo starting from Day 1. At Day 8 or 28 post infection, mice were haemodynamically characterized and subsequently sacrificed for immunohistological and molecular biology analyses. Eplerenone did not influence CVB3 load. Already at Day 8, 1.8‐fold (P < 0.05), 1.4‐fold (P < 0.05), 3.2‐fold (P < 0.01), and 2.1‐fold (P < 0.001) reduction in LV intercellular adhesion molecule 1 expression, presence of monocytes/macrophages, oxidative stress, and apoptosis, respectively, was observed in eplerenone‐treated vs. untreated CVB3‐infected mice. In vitro, eplerenone led to 1.4‐fold (P < 0.01) and 1.2‐fold (P < 0.01) less CVB3‐induced cardiomyocyte oxidative stress and apoptosis. Furthermore, collagen production was 1.1‐fold (P < 0.05) decreased in cardiac fibroblasts cultured with medium of eplerenone‐treated vs. untreated CVB3‐infected HL‐1 cardiomyocytes. These ameliorations were in vivo translated into prevention of cardiac fibrosis, as shown by 1.4‐fold (P < 0.01) and 2.1‐fold (P < 0.001) lower collagen content in the LV of eplerenone‐treated vs. untreated CVB3‐infected mice at Days 8 and 28, respectively. This resulted in an early and long‐lasting improvement of LV dimension and function, as indicated by reduced LV end‐systolic volume and end‐diastolic volume, and an increase in LV contractility (dP/dt_max) and LV relaxation (dP/dt_min), respectively (P < 0.05).

Conclusions

Early intervention with the MRA eplerenone modulates the acute host and defence reaction and prevents cardiac disease progression in experimental CVB3‐induced myocarditis without aggravation of viral load. The findings advocate for an initiation of therapy of viral myocarditis as early as possible, even before the onset of inflammation‐induced myocardial dysfunction. This may also have implications for coronavirus disease‐19 therapy.

A Toolbox of Potential Immune-Related Therapies for Inflammatory Cardiomyopathy

Myocarditis is a multifactorial disorder, characterized by an inflammatory reaction in the myocardium, predominantly triggered by infectious agents, but also by antigen mimicry or autoimmunity in susceptible individuals. Unless spontaneously resolved, a chronic inflammatory course concludes with cardiac muscle dysfunction portrayed by ventricular dilatation, clinically termed inflammatory cardiomyopathy (Infl-CM). Treatment strategies aim to resolve chronic inflammation and preserve cardiac function. Beside standard heart failure treatments, which only play a supportive role in this condition, systemic immunosuppressants are used to diminish inflammatory cell function at the cost of noxious side effects. To date, the treatment protocols are expert-based without large clinical evidence. This review describes concept and contemporary strategies to alleviate myocardial inflammation and sheds light on potential inflammatory targets in an evidence-based order.

Serelaxin Improves Regional Myocardial Function in Experimental Heart Failure: An In Vivo Cardiac Magnetic Resonance Study

Background

Animal studies demonstrated that serelaxin lessens fibrosis in heart failure. This study assessed its effect on myocardial deformation using cardiac magnetic resonance and elucidated its relationship to gene regulation and histology in a mouse heart failure model.

Methods and Results

C57BL/6J mice were subjected to SHAM (n=4) or transverse aortic constriction (TAC). At week 10, TAC mice were randomized to receive either serelaxin (0.5 mg/kg per day; n=11) or vehicle (n=13) for 4 weeks. Cardiac magnetic resonance imaging was performed at baseline and repeated at the end of the study (week 14). Cine images were used to calculate left ventricular (LV) global longitudinal, circumferential, and radial strain. Hearts were examined for histology and gene expression. Compared with SHAM, mice 10 weeks after TAC showed increased LV mass with significant decreases in LV deformation parameters, indicating subclinical deterioration of myocardial function. At week 14, TAC mice given serelaxin demonstrated significant improvements in all LV strain parameters and no decrease in LV stroke volume and ejection fraction compared with TAC mice given vehicle. A significant positive correlation between global circumferential strain and the extent of myocardial fibrosis was found, and global circumferential strain correlated significantly with the expression of heart failure genes in serelaxin‐treated mice.

Conclusions

Serelaxin improved cardiac magnetic resonance–derived myocardial deformation parameters as well as histomorphometric and gene expression findings in mice with heart failure. Cardiac magnetic resonance–derived myocardial mechanics correlate with histology and gene expression, stressing its utilization in myocardial remodeling.

Targeting CD20+ B-lymphocytes in inflammatory dilated cardiomyopathy with rituximab improves clinical course: a case series

Background 

The aetiology of dilated cardiomyopathy (DCM) is highly heterogeneous including genetic and/or acquired (infective, toxic, immune, endocrine, and nutritional) factors. The major part of acquired DCM in developed countries is caused by either viral or autoimmune myocarditis. It is believed that the activation of the T-lymphocyte cell system is the major pathomechanism underlying autoimmune myocarditis and inflammatory DCM (DCMi). However, in the hearts of a subset of patients, a significant number of CD20+ B-lymphocytes can be detected too. Limited information exists on the role of B-cell-dependent mechanisms in the progression of DCMi. Particularly CD20+ B-lymphocytes, which can be targeted by anti-CD20+ B-lymphocytes antibodies or inhibitors, might contribute to the pathogenesis of myocardial damage beyond antibody production.

Case summary 

Here, we present a case series of six patients with subacute and chronic endomyocardial biopsy-proven CD20+ B-lymphocyte-associated DCMi, where symptomatic heart failure therapy, with or without combined immunosuppressive therapy with steroid-based treatment regime, was insufficient to improve cardiac function. Five patients improved clinically several weeks after a standard infusion protocol with rituximab, a chimeric monoclonal antibody against the pan-B-cell surface molecule CD20.

Discussion 

Our case series shows that CD20+ B-lymphocyte persistence can play a pathophysiologic role in a subset of DCMi patients and highlights the potential of targeting CD20+ B cells in patients with prominent CD20+ B-lymphocyte persistence.

Telbivudine in chronic lymphocytic myocarditis and human parvovirus B19 transcriptional activity

Aims

Myocarditis is often associated with parvovirus B19 (B19V) persistence, which can induce vascular damage. Based on the antiviral and anti‐inflammatory properties of telbivudine, we aimed to evaluate its efficacy to protect B19V‐infected endothelial cells in vitro and to treat chronic lymphocytic myocarditis patients with B19V transcriptional activity.

Methods and results

We evaluated the endothelial‐protective potential of telbivudine in human microvascular endothelial cells‐1, which were infected with B19V. Treatment with 10 ng/mL of telbivudine decreased the B19V‐induced endothelial cell apoptosis and endothelial‐to‐mesenchymal transition. Along with this finding, telbivudine reduced the expression of transforming growth factor‐β1 and of tenascin‐C. The endothelial‐protective properties of telbivudine were also found in tumour necrosis factor‐α‐stressed human microvascular endothelial cells‐1. In addition, oxidative stress in angiotensin II‐stressed and transforming growth factor‐β1‐stressed HL‐1 cardiomyocytes and fibroblasts, respectively, was reduced upon telbivudine treatment, illustrating that telbivudine exerts multimodal protective effects. Based on these in vitro findings, four patients severely suffering from an endomyocardial biopsy‐proven myocarditis associated with B19V transcriptional activity (VP1/VP2‐mRNA positive) were treated with telbivudine (600 mg/dL) for 6 months in a single‐patient‐use approach. Follow‐up biopsies 6 months after treatment showed that VP1/VP2‐mRNA levels and CD3 cells decreased in all patients and were associated with an improvement in ejection fraction and New York Heart Association class. These findings were paralleled by a drop in tenascin‐C expression as shown via matrix‐assisted laser desorption ionization–imaging mass spectrometry.

Conclusions

Telbivudine exerts endothelial‐protective effects in B19V‐infected endothelial cells and improves chronic myocarditis associated with B19V transcriptional activity. These findings will be further evaluated in the clinical exploratory trial: the PreTopic study.