Emery-Dreifuss muscular dystrophy with dilated cardiomyopathy preceding skeletal muscle symptoms

Emery-Dreifuss muscular dystrophy is a slowly progressive skeletal muscle and joint disorder associated with cardiac complications. Dilated cardiomyopathy was the initial manifestation of Emery-Dreifuss muscular dystrophy in an 8-year-old girl. Despite normal muscle and myocardial biopsies, genetic testing revealed LMNA mutations. As Emery-Dreifuss muscular dystrophy is associated with minimal skeletal muscle weakness, cardiac complications can facilitate its diagnosis.

Comparative Transcriptomics of Immune Checkpoint Inhibitor Myocarditis Identifies Guanylate Binding Protein 5 and 6 Dysregulation

Immune checkpoint inhibitors (ICIs) are revolutionizing cancer treatment. Nevertheless, their increasing use leads to an increase of immune-related adverse events (irAEs). Among them, ICI-associated myocarditis (ICIM) is a rare irAE with a high mortality rate. We aimed to characterize the transcriptional changes of ICIM myocardial biopsies and their possible implications. Patients suspected for ICIM were assessed in the cardio-oncology units of University Hospitals Heidelberg and Kiel. Via RNA sequencing of myocardial biopsies, we compared transcriptional changes of ICIM (n = 9) with samples from dilated cardiomyopathy (DCM, n = 11), virus-induced myocarditis (VIM, n = 5), and with samples of patients receiving ICIs without any evidence of myocarditis (n = 4). Patients with ICIM (n = 19) showed an inconsistent clinical presentation, e.g., asymptomatic elevation of cardiac biomarkers (hs-cTnT, NT-proBNP, CK), a drop in left ventricular ejection fraction, or late gadolinium enhancement in cMRI. We found 3784 upregulated genes in ICIM (FDR < 0.05). In the overrepresented pathway ‘response to interferon-gamma’, we found guanylate binding protein 5 and 6 (compared with VIM: GBP5 (log2 fc 3.21), GBP6 (log2 fc 5.37)) to be significantly increased in ICIM on RNA- and protein-level. We conclude that interferon-gamma and inflammasome-regulating proteins, such as GBP5, may be of unrecognized significance in the pathophysiology of ICIM.

Scleredema with biopsy-confirmed cardiomyopathy: A case report

Scleredema is a rare cutaneous mucinosis characterized by diffuse swelling and non-pitting induration. A 63-year-old man reported a 5-year history of skin thickening of the trunk and a 3-week history of dyspnea. Echocardiography revealed diffuse hypokinesis. Skin biopsies obtained from the waist showed thickened dermis with mucin. Myocardial biopsies showed alcian blue-stained tissue between the muscle fibers. The patient was referred to a dermatologist for phototherapy. Cardiomyopathy should be considered in patients with scleredema. Scleredema usually has a good prognosis; however, the mortality risk could be high when accompanied by cardiomyopathy.

Early Detection of Checkpoint Inhibitor-Associated Myocarditis Using 68Ga-FAPI PET/CT

Objective: Checkpoint inhibitors (ICIs) have gained importance in recent years regarding the treatment of a variety of oncologic diseases. The possibilities of diagnosing cardiac adverse autoimmune effects of ICIs are still limited. We aimed to implement FAPI PET/CT imaging in detecting ICI-associated myocarditis.Methods: In a retrospective study, FAPI PET/CT scans of 26 patients who received ICIs from 01/2017 to 10/2019 were analyzed. We compared tracer enrichment in the heart of patients without any signs of a cardiac disease (n = 23) to three patients with suspected ICI-associated myocarditis. To exclude any significant coronary heart disease, cardiac catherization was performed. All three patients' myocardial biopsies were examined for inflammatory cells.Results: Three patients showed clinical manifestations of an ICI syndrome including myocarditis with elevated levels of hsTnT (175 pg/ml, 1,771 pg/ml, 157 pg/ml). Further cardiological assessments revealed ECG abnormalities, lymphocyte infiltration of the myocardium in the biopsies or wall motion abnormalities in echocardiography. These patients' FAPI PET/CTs showed cardiac enrichment of the marker which was less distinct or absent in patients receiving ICIs without any signs of immunological adverse effects or cardiac impairment (n = 23) [Median SUV myocarditis patients: 1.79 (IQR: 1.65, 1.85), median SUV non-myocarditis patients: 1.15 (IQR: 0.955, 1.52)].Conclusions: Apart from the successful implementation of ICIs in oncological treatments, ICI-associated myocarditis is still a challenging adverse effect. FAPI PET/CT may be used in order to identify affected patients at an early stage. Moreover, when integrated into cancer stage diagnostics, it contributes to cardiac risk stratification besides biomarker, ECG and echocardiography.

Impact of Sirolimus as a Primary Immunosuppressant on Myocardial Fibrosis and Diastolic Function Following Heart Transplantation

Background Myocardial fibrosis is an important contributor for development of diastolic dysfunction. We investigated the impact of sirolimus as primary immunosuppression on diastolic dysfunction and fibrosis progression among heart transplantation recipients. Methods and Results In 100 heart transplantation recipients who were either treated with a calcineurin inhibitor (CNI) (n=51) or converted from CNI to sirolimus (n=49), diastolic function parameters were assessed using serial echocardiograms and right heart catheterizations. Myocardial fibrosis was quantified on serial myocardial biopsies. After 3 years, lateral e′ increased within the sirolimus group but decreased in the CNI group (0.02±0.04 versus −0.02±0.04 m/s delta change; P =0.003, respectively). Both pulmonary capillary wedge pressure and diastolic pulmonary artery pressure significantly decreased in the sirolimus group but remained unchanged in the CNI group (−1.50±2.59 versus 0.20±2.20 mm Hg/year; P =0.02; and −1.72±3.39 versus 0.82±2.59 mm Hg/year; P =0.005, respectively). A trend for increased percentage of fibrosis was seen in the sirolimus group (8.48±3.17 to 10.10±3.0%; P =0.07) as compared with marginally significant progression in the CNI group (8.76±3.87 to 10.56±4.34%; P =0.04). The percent change in fibrosis did not differ significantly between the groups (1.62±4.67 versus 1.80±5.31%, respectively; P =0.88). Conclusions Early conversion to sirolimus is associated with improvement in diastolic dysfunction and filling pressures as compared with CNI therapy. Whether this could be attributed to attenuation of myocardial fibrosis progression with sirolimus treatment warrants further investigation.

Abstract 15809: 68 Gallium Fibroblast Activating Protein Inhibitor Positron Emission Tomography is Able to Diagnose Checkpoint Inhibitor-induced Myocarditis

Introduction: Checkpoint inhibitors (ICIs) have gained importance in recent years regarding the treatment of a variety of oncologic diseases. The possibilities of diagnosing cardiac adverse autoimmune effects of ICIs are still limited. We aimed to implement FAPI PET/CT imaging in detecting ICI-induced myocarditis. Methods: In a retrospective study, FAPI PET/CT scans of 26 patients who received ICIs from 01/2017 to 10/2019 were analyzed. We compared tracer enrichment in the heart of patients without any signs of a cardiac disease (n=23) to three patients with suspected ICI-induced myocarditis. To exclude any significant coronary heart disease, cardiac catherization was performed. Myocardial biopsies were examined, especially in regard to the infiltration of immune cells. Results: Three patients showed clinical manifestations of an ICI syndrome including myocarditis with elevated levels of hsTnT (175 pg/ml, 1771 pg/ml, 157 pg/ml). Further cardiological assessments revealed ECG abnormalities, lymphocyte infiltration of the myocardium in the biopsies or wall motion abnormalities in echocardiography. These patients’ FAPI PET/CTs showed a locally defined cardiac enrichment of the marker which was absent in patients receiving ICIs without any signs of immunological adverse effects and cardiac impairment (n=23) (Median SUV myocarditis patients: 1.79 (IQR: 1.65, 1.85), median SUV non-myocarditis patients: 1.15 (IQR: 0.955, 1.52)). Conclusions: Myocardial biopsy, the current gold standard of the diagnosis of ICI-induced myocarditis, is susceptible to sampling errors and results arrive within a few days. We provide first evidence that FAPI PET/CT is able to diagnose ICI-induced myocarditis and can demonstrate locally enhanced manifestation of ICI-induced myocarditis on time.

Abstract 16928: Discordant Mechanisms in Heart Failure and Hypertrophy

Introduction: Patients with heart failure and a preserved ejection fraction (HFpEF) present heart function abnormalities that remain poorly understood. Defining proteomic signature of HF that is independent of left ventricular hypertrophy (LVH) should allow for stratification of its subtypes and potential mechanism that contributes to the disease. Hypothesis: We hypothesized that HFpEF proteomic signature would be comprised of the hypertrophy and contractile protein phenotype. Methods: Intraoperative left ventricular (LV) myocardial biopsies were obtained from patients (n=21) recruited to undergo coronary artery bypass grafting (CABG). Patients were categorized to: control non-hypertensive (n=9), LVH (n=5), and HFpEF (n=7). Myocardial tissue was subfractionated: cytoplasmic- (neutral pH), myofilament- (acidic pH), and membrane-enriched extract (SDS-soluble). All fractions were assessed for protein quantity and Lys/Arg modifications using liquid chromatography mass spectrometry (LC-MS). Results: In HFpEF, 13% of the cardiac LV proteome changed compared to control heart, with a substantial proportion (77%) decreasing in quantity across all three cardiac fractions, while with LVH, 61% of the proteomic LV changes were increased. Although glycolysis and gluconeogenesis increased in both cardiopathies with respect to control, in HFpEF more subtly than in LVH. Modified proteome of the HFpEF was dominated by decreases in protein succinylation (e.g. ATP5L, THIM, IDHP, APOB, GSH1, KNTC1) and to a lesser degree in methylation (ROA3, HSP7C) or acetylation compared to control. This general trend of down-regulation of succinylation can be attributed to depletion in the levels of succinyl-CoA, the cofactor of enzymatic Lys succinylation. Importantly, there was a striking discordant activation/inhibition of cell death and proliferation pathways between the HFpEF and LVH. Two major upstream regulator clusters linked the proteome changes in cell growth and proliferation to RICTOR and Myc that showed completely opposite trends in LVH and HFpEF groups. Conclusions: HFpEF has a unique proteome signature compared to LV hypertrophy profile which does not arise from sub-proteome involved in contraction but rather is involved in overall cell death.

Accurate Noninvasive Assessment of Myocardial Iron Load in Advanced Heart Failure Patients

Background. Heart failure patients presenting with iron deficiency can benefit from systemic iron supplementation; however, there is the potential for iron overload to occur, which can seriously damage the heart. Therefore, myocardial iron (M-Iron) content should be precisely balanced, especially in already failing hearts. Unfortunately, the assessment of M-Iron via repeated heart biopsies or magnetic resonance imaging is unrealistic, and alternative serum markers must be found. This study is aimed at assessing M-Iron in patients with advanced heart failure (HF) and its association with a range of serum markers of iron metabolism. Methods. Left ventricle (LV) myocardial biopsies and serum samples were collected from 33 consecutive HF patients (25 males) with LV dysfunction (LV ejection fraction 22 (11) %; NT-proBNP 5464 (3308) pg/ml) during heart transplantation. Myocardial ferritin (M-FR) and soluble transferrin receptor (M-sTfR1) were assessed by ELISA, and M-Iron was determined by Instrumental Neutron Activation Analysis in LV biopsies. Nonfailing hearts ( n = 11 ) were used as control/reference tissue. Concentrations of serum iron-related proteins (FR and sTfR1) were assessed. Results. LV M-Iron load was reduced in all HF patients and negatively associated with M-FR ( r = − 0.37 , p = 0.05 ). Of the serum markers, sTfR1/logFR correlated with ( r = − 0.42 ; p = 0.04 ) and predicted (in a step-wise analysis, R 2 = 0.18 ; p = 0.04 ) LV M-Iron. LV M-Iron load (μg/g) can be calculated using the following formula: 210.24 – 22.869 × sTfR 1 / logFR . Conclusions. The sTfR1/logFR ratio can be used to predict LV M-Iron levels. Therefore, serum FR and sTfR1 levels could be used to indirectly assess LV M-Iron, thereby increasing the safety of iron repletion therapy in HF patients.

Comparative Effects of Single-Dose Cardioplegic Solutions Especially in Repeated Doses During Minimally Invasive Aortic Valve Surgery

Objective This study aims to compare del Nido cardioplegia (DNC) and histidine–tryptophan–ketoglutarate (HTK) cardioplegic solutions in minimally invasive aortic valve replacement (mini-AVR) surgery to discuss the safety level of myocardial protection and rationale for redosing intervals. Methods During the period from January 2017 to June 2019, 200 patients undergoing mini-AVR (solely or with concomitant procedures) were prospectively randomized to DNC ( n = 100) and HTK ( n = 100), both up to 90 minutes ischemic time. Patients with ischemic time over 90 minutes, needing a redosing, were further analyzed in 2 subgroups with DNC-R ( n = 30) and HTK-R ( n = 36). Sensitive biomarkers, in addition to routine biochemistry, were also documented at baseline (T1), after cessation of cardiopulmonary bypass (T2), and on the first postoperative day (T3). Transmural myocardial biopsies were sampled for staining. Results No statistical differences could be demonstrated in DNC and HTK groups with up to 90 minutes cross-clamp times in routine biochemical measurements and basic perioperative clinical outcomes. DNC-R showed significantly more arrhythmia/AV block incidence resulting in more extended intensive care unit (ICU) stay. Interleukin-6 and syndecan-1 in DNC and DNC-R groups were substantially higher at T2. Aquaporin-4 levels were significantly lower in the DNC-R group, demonstrating unsatisfactory response of cells to an excessive volume at T2. Conclusions DNC and HTK provided acceptable myocardial protection as single-dose applications. DNC-R had significantly unbalanced levels of biomarkers, and more arrhythmia/AV block incidence resulting in more extended ICU stay. For patients who may need redosing HTK may be preferable to DNC.

Direct effects of canagliflozin on human myocardial redox signalling: a novel role for SGLT1 inhibition

Background Recent clinical trials have demonstrated a role for sodium glucose cotransporter 2 (SGLT2) inhibitors in improving cardiovascular outcomes in heart failure patients, but the underlying mechanisms remain unknown. We investigated the direct effects of canagliflozin, a non-selective SGLT1/SGLT2 inhibitor on myocardial redox signalling in humans. Methods Study 1 included 364 patients undergoing cardiac surgery. Human right atrial appendage biopsies, obtained during surgery, were used to quantify the sources of superoxide (O2.-) and the gene expression of inflammation, fibrosis and myocardial stretch markers. In Study 2, myocardial biopsies from 51 patients were used ex vivo to study the direct effects of canagliflozin on O2.- generation and understand its role in controlling the activity of NADPH-oxidases and uncoupled nitric oxide synthase (NOS). Finally, we used differentiated H9C2 and human primary cardiomyocytes (hCM) to further characterise the key regulatory mechanisms (Study 3). Results SGLT1 was abundantly expressed in the human myocardial biopsies and hCM whilst SGLT2 was barely detectable. SGLT1 expression levels were positively correlated with basal O2.- production and the expression of natriuretic peptides, proinflammatory cytokines and pro-fibrotic markers in human myocardial biopsies from study 1. Incubation of human myocardium with canagliflozin significantly reduced basal and NADPH-oxidase-derived O2.- via AMP kinase (AMPK)-mediated suppression of GTP-activation and consequent reduction of membrane translocation of Rac1, an NADPH-oxidase subunit. This resulted in reduced oxidation and increased bioavailability of tetrahydrobiopterin, the nitric oxide synthase (NOS) co-factor essential for enzymatic coupling, leading to improved NOS coupling. These findings were replicated in hCM, where canagliflozin was shown to regulate AMP/ATP ratio, which could be upstream of AMPK activation. The effects of canagliflozin were significantly attenuated by knocking-down SGLT1 in hCM. Transcriptional profiling of hCM treated with canagliflozin revealed that canagliflozin had striking effects on myocardial redox signalling, causing suppression of apoptotic and inflammatory pathways in the human heart. Conclusions We demonstrate for the first time in humans that canagliflozin suppresses myocardial NADPH-oxidase activity and improves NOS coupling through an SGLT1/AMPK/Rac1-mediated pathway, leading to global anti-inflammatory and anti-apoptotic effects in the human myocardium. These findings provide a mechanistic basis for the beneficial effects of SGLT1/2 inhibitors in patients with heart failure. Funding Acknowledgement Type of funding source: Foundation. Main funding source(s): 1. British Heart Foundation (FS/16/15/32047 and PG/13/56/30383 to CA, CH/16/1/32013 to KC, and Centre of Research Excellence award RG/13/1/30181), 2. The Japanese Heart Rhythm Society-European Heart Rhythm Association fellowship grant sponsored by Biotronik.