Cardiac Biopsy Research Articles

Personalized Medicine Approach in a DCM Patient with LMNA Mutation Reveals Dysregulation of mTOR Signaling.

Background: Mutations in the Lamin A/C (LMNA) gene are responsible for about 6% of all familial dilated cardiomyopathy (DCM) cases which tend to present at a young age and follow a fulminant course. Methods: We report a 47-year-old DCM patient with severely impaired left ventricular ejection fraction and NYHA functional class IV despite optimal heart failure treatment. Whole-exome sequencing revealed an LMNA E161K missense mutation as the pathogenetic cause for DCM in this patient. We generated a patient-specific LMNA-knock in (LMNA-KI) in vitro model using mES cells. Results: Beta adrenergic stimulation of cardiomyocytes derived from LMNA-KI mES cells resulted in augmented mTOR signaling and increased dysregulation of action potentials, which could be effectively prevented by the mTOR-inhibitor rapamycin. A cardiac biopsy confirmed strong activation of the mTOR-signaling pathway in the patient. An off-label treatment with oral rapamycin was initiated and resulted in an improvement in left ventricular ejection fraction (27.8% to 44.5%), NT-BNP (8120 ng/L to 2210 ng/L) and NYHA functional class. Conclusion: We have successfully generated the first in vitro model to recapitulate a patient-specific LMNA E161K mutation which leads to a severe form of DCM. The model may serve as a template for individualized and specific treatment of heart failure.

What cardiologists should know about cardiac sarcoidosis in 2022?

Cardiac sarcoidosis (CS) is a potentially fatal condition when unrecognized or not treated adequately. The purpose of this review is to provide new strategies to increase clinical recognition of CS and to present an updated overview of the immunosuppressive treatments using most recent data published in the last 18 months. CS is an increasingly recognized pathology, and its diagnostic is made 20 times more often in the last two decades. Recent studies have shown that imaging alone usually lacks specificity to distinguish CS from other inflammatory cardiomyopathies. However, imaging can be used to increase significantly diagnostic yield of extracardiac and cardiac biopsy. Recent reviews have also demonstrated that nearly 25% of patients will be refractory to standard treatment with prednisone and that combined treatment with a corticosteroid-sparing agent is often necessary for a period that remains undetermined. CS is a complex pathology that should always require a biopsy attempt to have a histological proven diagnosis before starting immunosuppressive therapy consisting of corticosteroids with or without a corticosteroid-sparing agent.

Unusual diagnosis of feline cardiac lymphoma using cardiac needle biopsy

BackgroundCardiac tumors in cats are relatively rare, with lymphoma accounting for more than half of all cases. However, feline cardiac lymphoma is often diagnosed post-mortem, and it is difficult to diagnose while the cat is still alive. It is the first report of a direct, rather than estimative, diagnosis with cardiac needle biopsy of a living cat with cardiac lymphoma.Case presentationA 3-year-old domestic short-haired male cat experienced loss of energy and loss of appetite. Thoracic radiography and transthoracic echocardiography showed cardiomegaly with slight pleural effusion and cardiac tamponade due to pericardial effusion, respectively. In addition, partial hyperechoic and hypertrophy of the papillary muscle and myocardium were observed. Blood test showed an increase in cardiac troponin I levels. Pericardial fluid, removed by pericardiocentesis, was analyzed; however, the cause could not be determined. With the owner’s consent, pericardiectomy performed under thoracotomy revealed a discolored myocardium. Cardiac needle biopsy was performed with a 25G needle, and a large number of large atypical lymphocytes were collected; therefore, a direct diagnosis of cardiac lymphoma was made. Pathological examination of the pericardium diagnosed at a later date revealed T-cell large cell lymphoma. The cat underwent chemotherapy followed by temporary remission but died 60 days after the diagnosis. Postmortem, two-dimensional speckle-tracking echocardiography (data when alive) revealed an abnormal left ventricular myocardial deformation, which corresponded to the site of cardiac needle biopsy.ConclusionsThis rare case demonstrates that cardiac lymphoma should be added to the differential diagnosis in cats with myocardial hypertrophy and that the diagnosis can be made directly by thoracotomy and cardiac needle biopsy. In addition, the measurement of cardiac troponin I levels and local deformation analysis of the myocardium by two-dimensional speckle-tracking echocardiography may be useful in the diagnosis of cardiac tumors.

Activation of the mTORC1 and mitochondrial signaling under diabetic and hypertensive cardiomyopathy

Introduction: Type 2 Diabetes Mellitus (T2DM) and hypertension (HTN) are correlated with cardiovascular disease (CVD). The presence of HTN in T2DM will lead to risk elevation in CVD. Inflammation, hypertrophy, apoptosis and fibrosis can be found in these patients. However, the mechanisms involved haven’t been fully depicted. Methodology: Cardiac biopsies from interventricular septum were isolated from patients with T2DM and/or HTN. Differential protein expression was evaluated by proteomics (hybrid trapped ion mobility spectrometry) and PEAKS software. Ingenuity Pathway Analysis (IPA, Qiagen) was used to predict the implication of molecular pathways. Cultured cardiomyocytes were used to reveal the alteration of relevant pathways under hyperglycemic, hyperlipidemic and pro-hypertensive milieu mimicked by high glucose, high fatty-acid (HF) and/or angiotensin-II. Results: By proteomics, there is a huge difference between T2DM/HTN group and HTN in number of altered factors and its fold-change when compared with control. HTN induced a decrease of cardiac factors related to carbohydrate metabolism, mitochondrial homeostasis and respiration, while factors decreased in T2DM/HTN most related to metabolism and mitochondrial dysfunction. Also, T2DM/HTN increased fibrosis and apoptosis related factors. Interestingly, a potential regulation of mTOR complexes was suggested by bioinformatics. Thus, we confirmed the phosphorylation on Thr421/Ser424 of p70S6, a mTORC1 downstream mediator, under HF in cardiomyocytes. Also, we observed an enhanced phosphorylation on Thr172 of AMPKα, and a decreased expression of PGC1α and ACADm, in parallel to a lessening of ATP production. These alterations were abolished by rapamycin, an inhibitor of mTORC1 and metformin. Also, the silencing of a subunit of mTORC2, Rictor, induced a decrease of p-p70s6 under HF. Conclusion: T2DM/ HTN can lead to dramatic protein changes in heart and induce a synergy cooperation when combined. The mitochondrial alteration may be major responsible of cardiac dysfunction. In particular, mTORC1 can be activated under hyperlipidemia to further lead to β-oxidation reduction and ATP synthesis. Therefore, the regulation of the mTOR-mitochondria signaling could be essential for prognosis of heart failure in T2DM and HTN patients.

Immunotherapy-related cardiovascular toxicity: Development of a preclinical murine model of acute myocarditis

Immunotherapies represent a major advance in oncology and an increasing number of patients will benefit from them. However, activation of the immune system can lead to severe myocarditis with a fatality rate up to 50%. The pathophysiological mechanisms of myocarditis induced by anti-PD-1 and anti-CTLA-4, the most commonly used immune checkpoint inhibitor (ICIs), are poorly understood and require models to study this cardiotoxicity. PD-1 and CTLA-4 KO mouse models do show cardiomyopathy but still do not reflect the immuno-induced myocarditis observed in patients. Our objective is to develop a preclinical mouse model to characterize in vivo the pathophysiological mechanisms of ICIs-induced myocarditis. We used a syngeneic model with adult BALB/c mice grafted with murine melanoma cells. Ten days after graft, mice were treated every 2 days with peritoneal injection of a combination of anti-PD-1 (6.5 mg/kg) and anti-CTLA-4 (20 mg/kg) monoclonal antibodies. A group of ICIs-treated mice with melanoma also received diphtheria toxin to amplify the cardiotoxic response, by depletion of regulatory T cells. To follow-up the cardiac function, an ECG was recorded before each ICIs injection and 1 week after the 3rd injection before euthanasia. A submaxillary blood sample was taken before and after ICIs injection. To investigate inflammation, hearts were dissected for transcriptomic analysis and immunostaining. All transplanted mice developed a palpable melanocytic tumor. They maintained a stable clinical condition (no weight loss or signs of pain). ECG analysis showed some arrhythmias and numerous extrasystoles. Analyses are currently underway to determine the characteristics of the different intervals in each of the groups tested and to verify the significance of the results. qPCR analyzes are in progress to verify the inflammatory state of the myocardium. We are looking for changes in the expression of genes of the JAK/STAT pathway and of the NLRP3 inflammasome, including the GBP5 , GBP6 , and CCDC175 , CXCL9 , CXCL11 genes which have been described in cardiac biopsies from patients. This model of in vivo cardiotoxicity is very important to unravel the mechanisms that lead to immuno-induced myocarditis. The results obtained will be integrated with data from patients followed at the Cardio-Oncology center in Marseille and those from the in vitro hiPSC model in order to better understand the pathology and identify prognosis markers.

Characterization of the inflammasome IFN-dependent in hiPSC-derived endothelial cells from ICIs-induced myocarditis patients

Immune checkpoint inhibitors (ICIs) reactivate T cells to fight tumor cells, unraveling a new approach in cancer treatment. However, cardiovascular complications induced by these ICIs, especially myocarditis, have emerged as particularly dangerous complications with a mortality rate close to 50%. A recent study on cardiac biopsies showed that the IFN-γ pathway and inflammasome regulating proteins was specifically involved in myocarditis induced by ICIs treatment; this mechanism was not found in viral myocarditis and in dilated cardiomyopathies [1] . It is therefore crucial to set up models to study these pathophysiological mechanisms so that the benefit of immunotherapies is not compromised by their adverse cardiac effects. To better understand pathophysiological mechanisms of myocarditis induced by ICIs, we characterized the response to IFN-γ of endothelial cells (hiPSC-EC) generated from cells of patients with and without ICIs-induced myocarditis. We generated human-induced pluripotent stem cell (hiPSC), differentiated in hiPSC-EC, from cells of patients followed in the MediCO Center, Marseille. We considered two groups of patients: with myocarditis (Myoc) and without myocarditis (non-Myoc) following anti-PD-1/anti-CTLA4 immunotherapy. hiPSC-EC were treated with 10 ng/mL of IFN-γ during 48 h. Endothelial cells differentiated from hiPSC clones exhibited the characteristics expected for this cell type in all clones tested, both in the Myoc and non-Myoc patient groups. Stimulation by IFN-γ activated inflammatory intracellular signaling in hiPSC-EC, in particular overexpression of MHC class I and II, and PDL-1. Moreover, changes in the expression of genes of the JAK/STAT pathway and of the inflammasome, particularly the NLRP3 inflammasome, were observed in all groups of tested cells after the IFN-γ stimulation. However, the cells from Myoc patients seemed to be more impaired than those from non-Myoc patients. In particular, hiPSC-EC proliferation was more altered in this group by IFN-γ, and the expression of genes associated with the inflammatory response was strongly increased. Further analyses are in progress to confirm these preliminary data. These preliminary results, obtained in cells reprogrammed from cells of patients with immuno-induced myocarditis, are in agreement with the data published by Finke et al. (2021) in myocardial biopsies, indicating that these hiPSCs are a good model to study the pathophysiological mechanisms associated with the cardiotoxicitiy of anticancer immunotherapy.

Decreased expression of ErbB2 on left ventricular epicardial cells in patients with diabetes mellitus

We investigated the cell surface expression of ErbB receptors on left ventricular (LV) epicardial endothelial cells and CD105+ cells obtained from cardiac biopsies of patients undergoing coronary artery bypass grafting surgery (CABG). Endothelial cells and CD105+ non-endothelial cells were freshly isolated from LV epicardial biopsies obtained from 15 subjects with diabetes mellitus (DM) and 8 controls. The expression of ErbB receptors was examined using flow cytometry. We found that diabetes mellitus (DM) and high levels of hemoglobin A1C are associated with reduced expression of ErbB2. To determine if the expression of ErbB2 receptors is regulated by glucose levels, we examined the effect of high Glucose in human microvascular endothelial cells (HMEC-1) and CD105+ non-endothelial cells, using a novel flow cytometric approach to simultaneously determine the total level, cell surface expression, and phosphorylation of ErbB2. Incubation of cells in the presence of 25 mM d-glucose resulted in decreased cell surface but not total levels of ErbB2. The level of ErbB2 at the cell surface is controlled by disintegrin and metalloproteinase domain-containing protein 10 (ADAM10) that is expressed on LV epicardial cells. Inhibition of ADAM10 prevented the high glucose-dependent decrease in the cell surface expression of ErbB2. We suggest that high Glucose depresses ErbB receptor signaling in endothelial cells and cardiac progenitor cells via the promotion of ADAM10-dependent cleavage of ErbB2 at the cell surface, thus contributing to vascular dysfunction and adverse remodeling seen in diabetic patients.

P325 CARDIAC SARCOIDOSIS…TYPICAL CLINICAL PRESENTATION

Abstract We report the case of a 50–year–old man without previous medical hystory who was admitted to our department for recurrent syncopes for several months. Throughout the 24 hours ECG Holter it has been underlined several advanced atrioventricular block episodes, hence the patient underwent to definitive pacemaker implant. After 3 months, due to sustained ventricular tachycardia, the patient incurred a out–of–hospital cardiac arrest; the patient was subjeced to cardio pulmonary resuscitation with the restoration of the sinus rithm following defibrillation. Unfortunatly, due to the resuscitation maneuvers, sternal fracture resulted. During the hospitalization in the Cardiology department, he underwent coronary angiography wich showed non significant lesions. Cardiac Magnetic Resonance was also performed among the tests. The examination was found to be particularly hard to understand due to the presence of the sternal injury that deformed the pectus and affected dynamics of the right ventricle, causing systolic bulging of the subtricuspid region of the right ventricular wall. During the dynamic sequences, there was a mild bi–ventricular reduction in systolic function. In post contrast imaging, extended transmural LGE of the basal interventricular septum and right ventricular wall, as well as multifocal involvement of the left ventricle were found. Examination was not of univolcal interpretation: the patient was tranferred to another Center to perform MR PET wich was found to be strongy suggestive of sarcoidosis, later confirmed by extra cardiac biopsy. For this reason an ICD upgrade was performed along side the immunosoppressive therapy. Sarcoidosis is an inflammatory disease characterized by the presence of noncaseous granulomas in one or more organs or tissues; at the cardiac level it can “mimic” different cardiomyopathies as an insidious diagnosis. The presence of a post–traumatic pectus excavatum leads to dyskinesia of the rignt venticular wall, reduction of the bi–ventricular systolic funcion combine with an extensive late enhancement could suggest arrhytmogenic dysplasia with bi–ventricular involvement. However, by focusing on the clinical presentation (in particular the onset charaterized by unexplained advanced AV block in a young and healthy subjet and subsequent ventricular arrhytmias), through a multimodal and multidisciplinary imaging approach it was posible to diagnose sarcoidosis with cardiac involvement and refer the patient to adequate therapy.

Data Mining Identifies CCN2 and THBS1 as Biomarker Candidates for Cardiac Hypertrophy.

Cardiac hypertrophy is a condition that may contribute to the development of heart failure. In this study, we compare the gene-expression patterns of our in vitro stem-cell-based cardiac hypertrophy model with the gene expression of biopsies collected from hypertrophic human hearts. Twenty-five differentially expressed genes (DEGs) from both groups were identified and the expression of selected corresponding secreted proteins were validated using ELISA and Western blot. Several biomarkers, including CCN2, THBS1, NPPA, and NPPB, were identified, which showed significant overexpressions in the hypertrophic samples in both the cardiac biopsies and in the endothelin-1-treated cells, both at gene and protein levels. The protein-interaction network analysis revealed CCN2 as a central node among the 25 overlapping DEGs, suggesting that this gene might play an important role in the development of cardiac hypertrophy. GO-enrichment analysis of the 25 DEGs revealed many biological processes associated with cardiac function and the development of cardiac hypertrophy. In conclusion, we identified important similarities between ET-1-stimulated human-stem-cell-derived cardiomyocytes and human hypertrophic cardiac tissue. Novel putative cardiac hypertrophy biomarkers were identified and validated on the protein level, lending support for further investigations to assess their potential for future clinical applications.

Soluble Isoform of ST2 is a Cardiac Inducer of Collagen Deposition in an Ex Vivo Model of Obesity

IntroductionOne of the main cardiac mechanosensor is the IL‐33/ST2L complex composed by the allarmin IL‐33 released into extracellular space by damaged cells during cardiac overload and its receptor, ST2L, which their binding promotes cell survival and anti‐fibrotic signaling. After damage, to stop IL‐33/ST2L signal, resident cardiac cells release sST2, the soluble isoform of transmembrane receptor of ST2, which sequesters IL‐33, functioning as a decoy receptor and blocking its signal. In obesity, the sST2 become over express especially by hypertrophic fat cells. The aim of our study is to evaluate in an ex vivo model of obesity the role of sST2 in the promotion of collagen production by cardiac cells.MethodsTen obese nondiabetic male Zucker rats (OB) (fa/fa‐, 10 weeks of age) and 10 lean littermates (L) (Fa/+) at the age of 25 weeks were weighted and scarified according to Italian Ministry of Health Authorization (N°325/2015PR of 2015/04/05) and their heart and visceral adipose tissue (VAT) were collected for the analysis. VAT biopsies were cut in 30mg pieces and added into a co‐culture system with H9C2 for 6‐24 and 48 hours. At each time points, cells and culture medium were collected. In all samples were evaluated ST2 by ELISA and collagen were quantified by quantitative Sircol assay for measurement of both acid‐soluble and pepsin‐soluble collagens.ResultsOB cardiac biopsies showed higher protein level of both ST2 and collagen than L rats (p<0.02 and p<0.002 respectively) and the rat weight positively correlates with ST2 cardiac protein level (p<0.05). Co‐culture data demonstrated that OB VAT promotes ST2 releases in both cardiac and fat cells, resulting an incremental increase of sST2 release in cell culture medium than L VAT in time. sST2 quantification in correspondent H9C2 co‐cultured lysate is more incremented in OB than L H9C2 after 48h.total collagen quantification in co‐culture medium resulted higher in OB than L (p<0.05).ConclusionOur results demonstrated in a co‐culture system that obesity promotes sST2 increase in the heart and this promotes collagen releases by cardiac cells, suggesting sST2 role in activation of pro‐fibrotic signaling and detrimental heart remodeling.

Progressive Reduction in Right Ventricular Contractile Function Attributable to Altered Actin Expression in an Aging Mouse Model of Arrhythmogenic Cardiomyopathy.

Arrhythmogenic cardiomyopathy (ACM) is an inherited genetic disorder of desmosomal dysfunction, and PKP2 (plakophilin-2) has been reported to be the most common disease-causing gene when mutation-positive. In the early concealed phase, the ACM heart is at high risk of sudden cardiac death before cardiac remodeling occurs because of mistargeted ion channels and altered Ca2+ handling. However, the results of pathogenic PKP2 variants on myocyte contraction in ACM pathogenesis remain unknown. We studied the outcomes of a human truncating variant of PKP2 on myocyte contraction using a novel knock-in mouse model with insertion of thymidine in exon 5 of Pkp2, which mimics a familial case of ACM (PKP2-L404fsX5). We used serial echocardiography, electrocardiography, blood pressure measurements, histology, cardiomyocyte contraction, intracellular calcium measurements, and gene and protein expression studies. Serial echocardiography of Pkp2 heterozygous (Pkp2-Het) mice revealed progressive failure of the right ventricle (RV) in animals older than 3 months. By contrast, left ventricular function remained normal. ECGs of 6-month-old anesthetized Pkp2-Het mice showed normal baseline heart rates and QRS complexes. Cardiac responses to β-adrenergic agonist isoproterenol (2 mg/kg) plus caffeine (120 mg/kg) were also normal. However, adrenergic stimulation enhanced the susceptibility of Pkp2-Het hearts to tachyarrhythmia and sudden cardiac death. Histological staining showed no significant fibrosis or adipocyte infiltration in the RVs and left ventricles of 6- and 12-month-old Pkp2-Het hearts. Contractility assessment of isolated myocytes demonstrated progressively reduced Pkp2-Het RV cardiomyocyte function consistent with RV failure measured by echocardiography. However, aging Pkp2-Het and control RV myocytes loaded with intracellular Ca2+ indicator Fura-2 showed comparable Ca2+ transients. Western blotting of Pkp2-RV homogenates revealed a 40% decrease in actin, whereas actin immunoprecipitation followed by a 2,4-dinitrophenylhydrazine staining showed doubled oxidation level. This correlated with a 39% increase in troponin-I phosphorylation. In contrast, Pkp2-Het left ventricular myocytes had normal contraction, actin expression and oxidation, and troponin-I phosphorylation. Last, Western blotting of cardiac biopsies revealed that actin expression was 40% decreased in RVs of patients with end-stage ACM. During the early concealed phase of ACM, reduced actin expression drives loss of RV myocyte contraction, contributing to progressive RV dysfunction.

54-Year-Old Man With Acute Dyspnea on Exertion

54-Year-Old Man With Acute Dyspnea on Exertion

A multicenter, randomized, double-blind, placebo-controlled study to evaluate the efficacy of immunosuppression in biopsy-proven virus-negative myocarditis or inflammatory cardiomyopathy (IMPROVE-MC).

Myocarditis is frequently associated with poor prognosis as there is no evidence-based treatment. Therefore, current international recommendations indicate that a well-designed prospective trial to confirm benefits from immunosuppressive therapy is highly warranted. The aim of the IMPROVE-MC study is to assess the efficacy and safety of immunosuppressive treatment compared with placebo on top of the guideline-recommended medical therapy in patients with biopsy-proven virus-negative myocarditis/inflammatory cardiomyopathy. The IMPROVE-MC (ClinicalTrials.gov: NCT04654988) is a prospective, randomized, double-blind, placebo-controlled, parallel-group, multicenter trial that will recruit 100 adults, with biopsy-proven myocarditis/inflammatory cardiomyopathy, with left ventricular ejection fraction (LVEF) ≤ 45% and ≥ 3-month history of symptoms. Patients will be randomized (1:1 ratio) to a group treated with prednisone and azathioprine vs. placebo. Patients will undergo 1-year double-blind therapy followed by a 1-year observation period to assess the long-term effects of the treatment. Apart from a routine clinical work-up, all patients will undergo cardiac magnetic resonance (CMR) and biopsy during screening and 1 year after applying the therapy. Primary endpoint is a change from baseline in LVEF at 12 months. Secondary endpoints are related to clinical evaluation (including New York Heart Association class, distance in 6-minute walk test, number of patients with the need for hospitalization), laboratory findings (biomarkers of fibrosis and myocardial necrosis, concentration of anti-heart auto-antibodies, heart tissue immunohistologic assessment), diagnostic tools (e.g., changes of echocardiographic, CMR and Holter-ECG parameters) and quality of life. The IMPROVE-MC study will provide high-quality scientific data on the efficacy and safety of immunosuppressive therapy for patients with biopsy-proven myocarditis. Trial registration number and date of registration: ClinicalTrials.gov:NCT04654988; 04/12/2020.

Combination Therapy With Mycophenolate Mofetil And Prednisone In The Treatment Of Cardiac Sarcoidosis

Introduction Long-term immunosuppression is the mainstay of treatment for cardiac sarcoidosis (CS). While steroids are the cornerstone of therapy, steroid-sparing alternatives are considered second-line or adjunctive in the management of CS. We aimed to evaluate the efficacy of mycophenolate mofetil and steroids on the clinical and radiographic outcomes of patients with CS. Methods A retrospective chart review at a single academic medical center of patients with CS that were treated with prednisone or combination therapy with prednisone and MMF was conducted between 2019-2021. Baseline demographics, clinical data, echocardiography and PET data was collected pre and post-treatment. Improvement in disease was based on improvement in left ventricular ejection fraction (LVEF), reduction of arrhythmia burden, and regional maximum Standardized Uptake Value and percentage of inflammation on 18F-fluorodeoxyglucose positron emission tomography (FDG-PET). The parameters were then compared between the MMF and non- MMF group. Results There were 19 total patients (63% male and 52% black that were found to have CS- of which 7 had a positive cardiac or extracardiac biopsy. 17 patients were treated with combination therapy consisting of prednisone and MMF. Median follow-up between scans was 154 days in MMF group and 156.5 days in the non-MMF group. In the MMF group, there was an improvement in EF with a median of 6.5 (p 0.22), regional max SUV decreased by 1.35 (p <0.05) and percent inflammation decreased by a median of 22 percentage points (p 0.11). Of the 14 patients in the MMF group that had an underlying arrhythmia, 11 (78%) had a mitigated or absent arrhythmia burden. In the non-MMF group, the LVEF decreased by a median of 9 (p 0.22), regional max SUV was increased to 1.9 (p <0.05) and percent inflammation decreased by a median of 2 percentage points. 1 of the 2 patients in the non-MMF group showed an improvement in arrhythmia burden. Conclusion CS patients treated with combination therapy consisting of prednisone and MMF appeared to have radiographic and clinical evidence of improvement. MMF may be considered an effective adjunctive therapy to prednisone alone. Long-term immunosuppression is the mainstay of treatment for cardiac sarcoidosis (CS). While steroids are the cornerstone of therapy, steroid-sparing alternatives are considered second-line or adjunctive in the management of CS. We aimed to evaluate the efficacy of mycophenolate mofetil and steroids on the clinical and radiographic outcomes of patients with CS. A retrospective chart review at a single academic medical center of patients with CS that were treated with prednisone or combination therapy with prednisone and MMF was conducted between 2019-2021. Baseline demographics, clinical data, echocardiography and PET data was collected pre and post-treatment. Improvement in disease was based on improvement in left ventricular ejection fraction (LVEF), reduction of arrhythmia burden, and regional maximum Standardized Uptake Value and percentage of inflammation on 18F-fluorodeoxyglucose positron emission tomography (FDG-PET). The parameters were then compared between the MMF and non- MMF group. There were 19 total patients (63% male and 52% black that were found to have CS- of which 7 had a positive cardiac or extracardiac biopsy. 17 patients were treated with combination therapy consisting of prednisone and MMF. Median follow-up between scans was 154 days in MMF group and 156.5 days in the non-MMF group. In the MMF group, there was an improvement in EF with a median of 6.5 (p 0.22), regional max SUV decreased by 1.35 (p <0.05) and percent inflammation decreased by a median of 22 percentage points (p 0.11). Of the 14 patients in the MMF group that had an underlying arrhythmia, 11 (78%) had a mitigated or absent arrhythmia burden. In the non-MMF group, the LVEF decreased by a median of 9 (p 0.22), regional max SUV was increased to 1.9 (p <0.05) and percent inflammation decreased by a median of 2 percentage points. 1 of the 2 patients in the non-MMF group showed an improvement in arrhythmia burden. CS patients treated with combination therapy consisting of prednisone and MMF appeared to have radiographic and clinical evidence of improvement. MMF may be considered an effective adjunctive therapy to prednisone alone.

The Heart Awakens

<h3>Introduction</h3> Primary graft dysfunction (PGD) after orthotopic heart transplant (OHT) can be a challenging complication to manage. We present a 70 year-old male with severe PGD immediately after OHT that required mechanical circulatory support. <h3>Case Report</h3> The patient developed myocarditis at age 63 leading to dilated cardiomyopathy. By age 69, despite guideline-directed medical therapy, he required a HeartMate 3 ventricular assist device (VAD) as a bridge to transplant for progressive heart failure. He was discharged and listed for OHT. Five months later, he was admitted for ventricular tachycardia storm and his listing status was upgraded. After 3 days, a donor organ with mild left ventricular (LV) systolic dysfunction was accepted for OHT. Intra-operatively, the transplanted heart showed limited contractility, despite epicardial pacing (cross clamp time 237 minutes, warm ischemic time 60 minutes). Therefore, biventricular CentriMag VADs were implanted. Post-operative ECG showed a slow ventricular escape rhythm (Figure 1A). On post-operative day (POD) 5, due to left hemothorax, he returned to the operating room, where improved cardiac contractions were noted. Serial cardiac biopsies showed normal myocardium and no rejection (Figure 1B, 1D). Over the next 2 days, the heart regained contractility. ECG showed a junctional escape rhythm (Figure 1C). On POD 7, the transplanted heart showed recovery and the Centrimag VADs were explanted. By POD 12, he was weaned off vasoactive medications and transferred to the ward. Eventually, on POD 23, he was discharged home with a permanent pacemaker. <h3>Summary</h3> This case demonstrates severe PGD in the context of pre-existing mild donor LV dysfunction that was successfully managed by mechanical circulatory support as a bridge to recovery. A potential contributor to graft dysfunction may be myocyte stunning by antiarrhythmic medications infused pre-operatively for ventricular tachycardia storm. This case shows the utility of donor hearts with LV systolic dysfunction even in the presence of other risk factors for PGD.

Uncovering the molecular identity of cardiosphere-derived cells (CDCs) by single-cell RNA sequencing

Cardiosphere-derived cells (CDCs) generated from human cardiac biopsies have been shown to have disease-modifying bioactivity in clinical trials. Paradoxically, CDCs’ cellular origin in the heart remains elusive. We studied the molecular identity of CDCs using single-cell RNA sequencing (sc-RNAseq) in comparison to cardiac non-myocyte and non-hematopoietic cells (cardiac fibroblasts/CFs, smooth muscle cells/SMCs and endothelial cells/ECs). We identified CDCs as a distinct and mitochondria-rich cell type that shared biological similarities with non-myocyte cells but not with cardiac progenitor cells derived from human-induced pluripotent stem cells. CXCL6 emerged as a new specific marker for CDCs. By analysis of sc-RNAseq data from human right atrial biopsies in comparison with CDCs we uncovered transcriptomic similarities between CDCs and CFs. By direct comparison of infant and adult CDC sc-RNAseq data, infant CDCs revealed GO-terms associated with cardiac development. To analyze the beneficial effects of CDCs (pro-angiogenic, anti-fibrotic, anti-apoptotic), we performed functional in vitro assays with CDC-derived extracellular vesicles (EVs). CDC EVs augmented in vitro angiogenesis and did not stimulate scarring. They also reduced the expression of pro-apoptotic Bax in NRCMs. In conclusion, CDCs were disclosed as mitochondria-rich cells with unique properties but also with similarities to right atrial CFs. CDCs displayed highly proliferative, secretory and immunomodulatory properties, characteristics that can also be found in activated or inflammatory cell types. By special culture conditions, CDCs earn some bioactivities, including angiogenic potential, which might modify disease in certain disorders.

Electron Microscopy Reveals Evidence of Perinuclear Clustering of Mitochondria in Cardiac Biopsy-Proven Allograft Rejection.

Acute cellular rejection is a major complication in heart transplantation. We focus on the analysis of new ultrastructural findings in cardiac biopsy rejection based on mitochondrial intracellular organization. This study includes heart transplanted patients from a single center who were referred for endomyocardial biopsies as a scheduled routine screening. Participants were divided into two groups: patients transplanted without allograft rejection (Grade 0R), and patients with biopsy-proven allograft rejection (Grade ≥ 2R). Using electronic microscopy, we detected a significant increase in the volume density of mitochondria (p < 0.0001) and dense bodies (p < 0.01) in the rejection group. The most relevant finding was the presence of local accumulations of mitochondria close to the nuclear envelope, pressing and molding the morphology of this membrane in all rejection samples (100%). We identified this perinuclear clustering of mitochondria phenomenon in a 68 ± 27% of the total cardiac nucleus observed from rejection samples. We did not observe this phenomenon in any non-rejection samples, reflecting excellent sensitivity and specificity. We have identified a specific phenomenon affecting the architecture of the nuclear membrane—perinuclear clustering of mitochondria—in endomyocardial biopsies from patients with cardiac rejection. This ultrastructural approach might complement and improve the diagnosis of rejection.

Cardiac myosin mechanochemistry underlies left ventricular dysfunction in human ischemic heart failure

Prolonged occlusion of the coronary arteries can lead to ischemic heart failure (IHF). Molecular changes within the myocardium during IHF are not fully understood. Accordingly, we aimed to characterize the biophysical properties of myocardial contractile proteins in IHF. Ten age-matched human males with similar BMI were included in the study. Cardiac biopsies of left ventricular free wall were taken from patients with ischemic heart failure (IHF, n=5) at the time of heart transplant or from organ donors with no previous history of ischemic heart failure (controls, n=5).

Should add-hoc cardiac biopsy be routine in patients with cardiomyopathy of unknown etiology undergoing electrical storm ablation?

Should add-hoc cardiac biopsy be routine in patients with cardiomyopathy of unknown etiology undergoing electrical storm ablation?

Case Report: Whole Exome Sequencing Identifies Compound Heterozygous Variants in TSFM Gene Causing Juvenile Hypertrophic Cardiomyopathy

We report a case of hypertrophic cardiomyopathy and lactic acidosis in a 3-year-old female. Cardiac and skeletal muscles biopsies exhibited mitochondrial hyperplasia with decreased complex IV activity. Whole exome sequencing identified compound heterozygous variants, p.Arg333Trp and p.Val119Leu, in TSFM, a nuclear gene that encodes a mitochondrial translation elongation factor, resulting in impaired oxidative phosphorylation and juvenile hypertrophic cardiomyopathy.