Case Report First-in-Man Method Description: Left Ventricular Unloading With iVAC2L During Veno-Arterial Extracorporeal Membrane Oxygenation

Veno-arterial extracorporeal membrane oxygenation (V-A ECMO) is increasingly used in bi-ventricular failure with cardiogenic shock to maintain systemic perfusion. Nonetheless, it tends to increase left ventricular (LV) afterload and myocardial oxygen demand. In order to mitigate these negative effects on the myocardium, an Impella CP® (3.5 L/min Cardiac Output) can be used in conjunction with V-A ECMO (ECMELLA approach). We implemented this strategy in a patient with severe acute myocarditis complicated by cardiogenic shock. Due to a hemolysis crisis, Impella CP® had to be substituted with PulseCath iVAC2L®, which applies pulsatile flow to unload the LV. A subsequent improvement in LV systolic function was noted, with increased LV ejection fraction (LVEF), LV end-diastolic diameter (LVEDD) reduction, and a reduction in plasma free hemoglobin. This case documents the efficacy of iVAC2L in replacing Impella CP as a LV vent during V-A ECMO, with less hemolysis

Protease-Activated Receptor-2 Regulates the Innate Immune Response to Viral Infection in a Coxsackievirus B3–Induced Myocarditis

ObjectivesThis study sought to evaluate the role of protease-activated receptor-2 (PAR2) in coxsackievirus B3 (CVB3)–induced myocarditis.BackgroundAn infection with CVB3 leads to myocarditis. PAR2 modulates the innate immune response. Toll-like receptor-3 (TLR3) is crucial for the innate immune response by inducing the expression of the antiviral cytokine interferon-beta (IFNβ).MethodsTo induce myocarditis, wild-type (wt) and PAR2 knockout (ko) mice were infected with 105 plaque-forming units CVB3. Mice underwent hemodynamic measurements with a 1.2-F microconductance catheter. Wt and PAR2ko hearts and cardiac cells were analyzed for viral replication and immune response with plaque assay, quantitative polymerase chain reaction, Western blot, and immunohistochemistry.ResultsCompared with wt mice, PAR2ko mice and cardiomyocytes exhibited a reduced viral load and developed no myocarditis after infection with CVB3. Hearts and cardiac fibroblasts from PAR2ko mice expressed higher basal levels of IFNβ than wt mice did. Treatment with CVB3 and polyinosinic:polycytidylic acid led to higher IFNβ expression in PAR2ko than in wt fibroblasts and reduced virus replication in PAR2ko fibroblasts was abrogated by neutralizing IFNβ antibody. Overexpression of PAR2 reduced the basal IFNβ expression. Moreover, a direct interaction between PAR2 and Toll-like receptor 3 was observed. PAR2 expression in endomyocardial biopsies of patients with nonischemic cardiomyopathy was positively correlated with myocardial inflammation and negatively with IFNβ expression and left ventricular ejection fraction.ConclusionsPAR2 negatively regulates the innate immune response to CVB3 infection and contributes to myocardial dysfunction. The antagonism of PAR2 is of therapeutic interest to strengthen the antiviral response after an infection with a cardiotropic virus

Midkine drives cardiac inflammation by promoting neutrophil trafficking and NETosis in myocarditis

Heart failure due to dilated cardiomyopathy is frequently caused by myocarditis. However, the pathogenesis of myocarditis remains incompletely understood. Here, we report the presence of neutrophil extracellular traps (NETs) in cardiac tissue of patients and mice with myocarditis. Inhibition of NET formation in experimental autoimmune myocarditis (EAM) of mice substantially reduces inflammation in the acute phase of the disease. Targeting the cytokine midkine (MK), which mediates NET formation in vitro, not only attenuates NET formation in vivo and the infiltration of polymorphonuclear neutrophils (PMNs) but also reduces fibrosis and preserves systolic function during EAM. Low-density lipoprotein receptor-related protein 1 (LRP1) acts as the functionally relevant receptor for MK-induced PMN recruitment as well as NET formation. In summary, NETosis substantially contributes to the pathogenesis of myocarditis and drives cardiac inflammation, probably via MK, which promotes PMN trafficking and NETosis. Thus, MK as well as NETs may represent novel therapeutic targets for the treatment of cardiac inflammation

Impairment of Immunoproteasome Function by β5i/LMP7 Subunit Deficiency Results in Severe Enterovirus Myocarditis

Proteasomes recognize and degrade poly-ubiquitinylated proteins. In infectious disease, cells activated by interferons (IFNs) express three unique catalytic subunits β1i/LMP2, β2i/MECL-1 and β5i/LMP7 forming an alternative proteasome isoform, the immunoproteasome (IP). The in vivo function of IPs in pathogen-induced inflammation is still a matter of controversy. IPs were mainly associated with MHC class I antigen processing. However, recent findings pointed to a more general function of IPs in response to cytokine stress. Here, we report on the role of IPs in acute coxsackievirus B3 (CVB3) myocarditis reflecting one of the most common viral disease entities among young people. Despite identical viral load in both control and IP-deficient mice, IP-deficiency was associated with severe acute heart muscle injury reflected by large foci of inflammatory lesions and severe myocardial tissue damage. Exacerbation of acute heart muscle injury in this host was ascribed to disequilibrium in protein homeostasis in viral heart disease as indicated by the detection of increased proteotoxic stress in cytokine-challenged cardiomyocytes and inflammatory cells from IP-deficient mice. In fact, due to IP-dependent removal of poly-ubiquitinylated protein aggregates in the injured myocardium IPs protected CVB3-challenged mice from oxidant-protein damage. Impaired NFκB activation in IP-deficient cardiomyocytes and inflammatory cells and proteotoxic stress in combination with severe inflammation in CVB3-challenged hearts from IP-deficient mice potentiated apoptotic cell death in this host, thus exacerbating acute tissue damage. Adoptive T cell transfer studies in IP-deficient mice are in agreement with data pointing towards an effective CD8 T cell immune. This study therefore demonstrates that IP formation primarily protects the target organ of CVB3 infection from excessive inflammatory tissue damage in a virus-induced proinflammatory cytokine milieu

Quantification of HLA class I molecules on renal cell carcinoma using Edman degradation

<p>Abstract</p> <p>Background</p> <p>Unimpaired HLA class I antigen presentation is a prerequisite for the recognition of tumor cells by cytotoxic T lymphocytes and thus essential for the success of anticancer immunotherapeutic concepts. Several approaches have been taken in the immunotherapy of metastatic renal cell carcinoma (RCC), however of limited success. HLA loss or down-regulation have often been reported and might interfere with immunotherapeutic approaches aimed at the recognition of HLA-presented peptides.</p> <p>Methods</p> <p>We employed a quantitative method of molecular analysis for the comparison of HLA amounts on primary tumor, normal kidney and metastases of RCC, using Edman degradation. We analyzed a series of 47 RCC samples including corresponding renal parenchyma, local lymph node metastases and distant metastases.</p> <p>Results</p> <p>Results of quantitative Edman degradation revealed significantly higher HLA yields on primary tumor and metastases compared to normal kidney tissue. This effect was shown not to result from infiltrating immune cells, since tumor-infiltrating lymphocytes had no influence on the overall HLA recovery from tumor tissue. Unexpectedly, we found a higher amount of HLA class I molecules on distant metastases compared to local lymph node metastases.</p> <p>Conclusion</p> <p>Edman degradation allows the direct quantitative comparison of HLA class I protein expression by tumor or normal tissue and metastases of RCC patients. Our results raise hopes for improving the success and effectiveness of future immunotherapeutic concepts for metastatic RCC.</p

The Reno-Vascular A2B Adenosine Receptor Protects the Kidney from Ischemia

Using gene-targeted mice, Holger Eltzschig and colleagues identify the A2B adenosine receptor as a novel therapeutic target for providing protection from renal ischemia

Dilated cardiomyopathy:causes, mechanisms, and current and future treatment approaches

Dilated cardiomyopathy is conventionally defined as the presence of left ventricular or biventricular dilatation or systolic dysfunction in the absence of abnormal loading conditions (eg, primary valve disease) or significant coronary artery disease sufficient to cause ventricular remodelling. This definition has been recognised as overly restrictive, as left ventricular hypokinesis without dilation could be the initial presentation of dilated cardiomyopathy. The causes of dilated cardiomyopathy comprise genetic (primary dilated cardiomyopathy) or acquired factors (secondary dilated cardiomyopathy). Acquired factors include infections, toxins, cancer treatment, endocrinopathies, pregnancy, tachyarrhythmias, and immune-mediated diseases. 5-15% of patients with acquired dilated cardiomyopathy harbour a likely pathogenic or pathogenic gene variant (ie, gene mutation). Therefore, the diagnostic tests and therapeutic approach should always consider both genetic and acquired factors. This Seminar will focus on the current multidimensional diagnostic and therapeutic approach and discuss the underlying pathophysiology that could drive future treatments aiming to repair or replace the existing gene mutation, or target the specific inflammatory, metabolic, or pro-fibrotic drivers of genetic or acquired dilated cardiomyopathy