Association of Complement and MAPK Activation With SARS-CoV-2-Associated Myocardial Inflammation

IMPORTANCE Myocardial injury is a common feature of patients with SARS-CoV-2 infection. However, the cardiac inflammatory processes associated with SARS-CoV-2 infection are not completely understood. OBJECTIVE To investigate the inflammatory cardiac phenotype associated with SARS-CoV-2 infection compared with viralmyocarditis, immune-mediatedmyocarditis, and noninflammatory cardiomyopathy by integrating histologic, transcriptomic, and proteomic profiling. DESIGN, SETTING, AND PARTICIPANTS This case serieswas a cooperative study between the Ludwig Maximilian University Hospital Munich and the Cardiopathology Referral Center at the University of Tubingen in Germany. A cohort of 19 patients with suspectedmyocarditis was examined; of those, 5 patients were hospitalized with SARS-CoV-2 infection between March and May 2020. Cardiac tissue specimens from those 5 patients were compared with specimens from 5 patients with immune-mediatedmyocarditis, 4 patients with non-SARS-CoV-2 viralmyocarditis, and 5 patients with noninflammatory cardiomyopathy, collected from January to August 2019. EXPOSURES Endomyocardial biopsy. MAIN OUTCOMES AND MEASURES The inflammatory cardiac phenotypeswere measured by immunohistologic analysis, RNA exome capture sequencing, and mass spectrometry-based proteomic analysis of endomyocardial biopsy specimens. RESULTS Among 19 participants, the median age was 58 years (range, 37-76 years), and 15 individuals (79%) were male. Data on race and ethnicity were not collected. The abundance of CD163+ macrophages was generally higher in the cardiac tissue of patients with myocarditis, whereas lymphocyte counts were lower in the tissue of patients with SARS-CoV-2 infection vs patients with non-SARS-CoV-2 virus-associated and immune-mediatedmyocarditis. Among those with SARS-CoV-2 infection, components of the complement cascade, including C1q subunits (transcriptomic analysis: 2.5-fold to 3.6-fold increase; proteomic analysis: 2.0-fold to 3.4-fold increase) and serine/cysteine proteinase inhibitor clade G member 1 (transcriptomic analysis: 1.7-fold increase; proteomic analysis: 2.6-fold increase), belonged to the most commonly upregulated transcripts and differentially abundant proteins. In cardiac macrophages, the abundance of C1q was highest in SARS-CoV-2 infection. Assessment of important signaling cascades identified an upregulation of the serine/threonine mitogen-activated protein kinase pathways. CONCLUSIONS AND RELEVANCE This case series found that the cardiac immune signature varied in inflammatory conditions with different etiologic characteristics. Future studies are needed to examine the role of these immune pathways inmyocardial inflammation

Exploration of analgesia with tramadol in the Coxsackievirus B3 myocarditis mouse model

Infection of mice with Coxsackievirus B3 (CVB3) triggers inflammation of the heart and this mouse model is commonly used to investigate underlying mechanisms and therapeutic aspects for viral myocarditis. Virus-triggered cytotoxicity and the activity of infiltrating immune cells contribute to cardiac tissue injury. In addition to cardiac manifestation, CVB3 causes cell death and inflammation in the pancreas. The resulting pancreatitis represents a severe burden and under such experimental conditions, analgesics may be supportive to improve the animals' well-being. Notably, several known mechanisms exist by which analgesics can interfere with the immune system and thereby compromise the feasibility of the model. We set up a study aiming to improve animal welfare while ensuring model integrity and investigated how tramadol, an opioid, affects virus-induced pathogenicity and immune response in the heart. Tramadol was administered seven days prior to a CVB3 infection in C57BL/6 mice and treatment was continued until the day of analysis. Tramadol had no effect on the virus titer or viral pathogenicity in the heart tissue and the inflammatory response, a hallmark of myocardial injury, was maintained. Our results show that tramadol exerts no disruptive effects on the CVB3 myocarditis mouse model and, therefore, the demonstrated protocol should be considered as a general analgesic strategy for CVB3 infection

Mitigated viral myocarditis in A/J mice by the immunoproteasome inhibitor ONX 0914 depends on inhibition of systemic inflammatory responses in CoxsackievirusB3 infection

A preclinical model of troponin I-induced myocarditis (AM) revealed a prominent role of the immunoproteasome (ip), the main immune cell-resident proteasome isoform, in heart-directed autoimmunity. Viral infection of the heart is a known trigger of cardiac autoimmunity, with the ip enhancing systemic inflammatory responses after infection with a cardiotropic coxsackievirusB3 (CV). Here, we used ip-deficient A/J-LMP7(-/-) mice to investigate the role of ip-mediated effects on adaptive immunity in CV-triggered myocarditis and found no alteration of the inflammatory heart tissue damage or cardiac function in comparison to wild-type controls. Aiming to define the impact of the systemic inflammatory storm under the control of ip proteolysis during CV infection, we targeted the ip in A/J mice with the inhibitor ONX 0914 after the first cycle of infection, when systemic inflammation has set in, well before cardiac inflammation. During established acute myocarditis, the ONX 0914 treatment group had the same reduction in cardiac output as the controls, with inflammatory responses in heart tissue being unaffected by the compound. Based on these findings and with regard to the known anti-inflammatory role of ONX 0914 in CV infection, we conclude that the efficacy of ip inhibitors for CV-triggered myocarditis in A/J mice relies on their immunomodulatory effects on the systemic inflammatory reaction

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

Expression of Ksp-cadherin during kidney development and in renal cell carcinoma

Cadherins are a large family of cell–cell adhesion molecules acting in a homotypic, homophilic manner that play an important role in the maintenance of tissue integrity. In the human kidney, several members of the cadherin family (including E- and N-cadherin, cadherin-6, -8 and -11) are expressed in a controlled spatiotemporal pattern. Cadherin-16, also called kidney-specific (Ksp-) cadherin, is exclusively expressed in epithelial cells of the adult kidney. In renal cell carcinomas (RCCs), which are considered to originate from epithelial kidney tubular cells, a complex pattern of cadherin expression can be observed, but Ksp-cadherin expression has not been analysed so far. In the present study, we show that the expression of Ksp-cadherin is completely abrogated in RCCs. Whereas Ksp-cadherin can be detected at later stages of tubulogenesis during human renal development and in the distal tubules of adult kidneys, no expression was found by immunohistochemistry or Western blot analysis in RCC tumour tissues and several RCC cell lines. However, despite the lack of protein expression, mRNA synthesis of Ksp-cadherin could be detected by reverse transcriptase–polymerase chain reaction analysis in all RCC tissues and most of the RCC cell lines studied, although at a reduced level. The loss of Ksp-cadherin protein was only observed in the malignant part of the tumour kidneys, whereas in the normal part of the affected kidneys Ksp-cadherin expression was clearly detected. These results indicate a downregulation of Ksp-cadherin in RCC and suggest a role for this cell adhesion molecule in tumour suppression

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

The prevalence of enteroviral capsid protein vp1 immunostaining in pancreatic islets in human type 1 diabetes.

addresses: Institute of Biomedical and Clinical Sciences, Peninsula Medical School, Plymouth, UK.The final publication is available at link.springer.com/article/10.1007%2Fs00125-009-1276-0Evidence that the beta cells of human patients with type 1 diabetes can be infected with enterovirus is accumulating, but it remains unclear whether such infections occur at high frequency and are important in the disease process. We have now assessed the prevalence of enteroviral capsid protein vp1 (vp1) staining in a large cohort of autopsy pancreases of recent-onset type 1 diabetic patients and a range of controls

Compensatory upregulation of anti-beta-adrenergic receptor antibody levels might prevent heart failure presentation in pediatric myocarditis

BACKGROUND: Myocarditis can be associated with severe heart failure and is caused by different inflammatory and autoimmune responses. The aim of this study was to describe the immunological response in children with myocarditis by analyzing anti-beta-adrenergic receptor antibodies (anti-β-AR Abs). METHODS: Sera of children who were hospitalized with biopsy-proven myocarditis were prospectively collected between April 2017 and March 2019. Anti-β1-AR Ab, anti-β2-AR Ab, and anti-β3-AR Ab were quantified by a CE-certified ELISA kit. According to normal values for immunoglobulin G (IgG), three age groups, 5–17 years, were defined. Children without inflammatory cardiac pathology and no heart failure signs were served as a control group. RESULTS: We compared 22 patients with biopsy-proven myocarditis and 28 controls. The median age (interquartile range) of the myocarditis group (MYC) was 12.1 (2.7–16.4) years, 13 men, left ventricular ejection fraction (LVEF) 51% and for control group, the median age was 5.0 (3.0–6.8) years, nine men, LVEF 64%. Myocarditis patients in the age group >5–17 years showed significantly higher anti-β3-AR Ab levels as compared to controls (p = 0.014). Lower anti-β2-AR Ab and anti-β3-AR Ab levels were significantly correlated with higher left ventricular diameters in myocarditis patients. The event-free survival using a combined endpoint (mechanical circulatory support [MCS], transplantation, and/or death) was significantly lower in myocarditis patients with antibody levels below the median as compared to myocarditis patients with antibody levels ≥ the median. CONCLUSION: Anti-β-AR Ab levels are increased in children with myocarditis and >5 years of age. These antibodies might be upregulated compensatory to prevent further cardiac deterioration. A worse event-free survival in patients with lower anti-β-AR Ab levels might be a therapeutic target for immunoglobulin substitution