[Catheter-based atrial appendage closure-current data and future developments]. / Der katheterbasierte Vorhofohrverschluss ­ aktuelle Daten und künftige Entwicklungen.

In Germany more than 1.6 million patients suffer from atrial fibrillation (AF). Within the next decades this number will substantially increase due to current demographic trends with the increasing average age of the population. When untreated, patients with atrial fibrillation have a five times higher risk for stroke as compared with a control cohort. A potent stroke prevention therapy reducing the risk of stroke by approximately 70-80% is primarily treatment with new oral anticoagulants (NOACs). The risk scores for stroke (CHA2DS2-VASc) and major bleeding (HAS-BLED) in patients with atrial fibrillation share common variables, so that patients with the highest stroke risk often carry a very high bleeding risk. A significant number of patients (ca. 20-30%) are, however, not eligible for long-term anticoagulation, e.g. because of a high bleeding risk. For this population there is an urgent need for alternative stroke prevention strategies, such as catheter-based percutaneous left atrial appendage closure. Current data about the efficiency and safety of this treatment as well as a discussion of ongoing recruitment for randomized studies are discussed in this review.

[Catheter-based closure of the left atrial appendage : Stroke prevention in atrial fibrillation]. / Der katheterbasierte Verschluss des linken Vorhofohrs : Schlaganfallprävention bei Vorhofflimmern.

In patients with nonvalvular atrial fibrillation, >90 % of thrombi are detected in the left atrial appendage (LAA). In particular these observations have resulted in the development of catheter-based LAA closure as an approach for stroke prevention in patients with nonvalvular atrial fibrillation in recent years. A preliminary randomized trial provided promising data with respect to efficacy and safety of this approach as compared to anticoagulation with warfarin. The safety of the procedure has been significantly improved in recent years due to procedural experience and refinement of implanted devices. In current clinical practice, this approach is particularly used for patients with nonvalvular atrial fibrillation, a significant ischemic risk (CHA2DS2-VASc score ≥2), and a high bleeding risk, i. e., in patients in whom there are relevant concerns with respect to long-term anticoagulation. The present article discusses the data from randomized clinical studies and registries, the present guideline recommendations, and the practical clinical use of LAA closure for stroke prevention.

Adiponectin promotes coxsackievirus B3 myocarditis by suppression of acute anti-viral immune responses.

Adiponectin (APN) is an immunomodulatory adipocytokine that improves outcome in patients with virus-negative inflammatory cardiomyopathy and mice with autoimmune myocarditis. Here, we investigated whether APN modulates cardiac inflammation and injury in coxsackievirus B3 (CVB3) myocarditis. Myocarditis was induced by CVB3 infection of APN-KO and WT mice. APN reconstitution was performed by adenoviral gene transfer. Expression analyses were performed by qRT-PCR and immunoblot. Cardiac histology was analyzed by H&E-stain and immunohistochemistry. APN-KO mice exhibited diminished subacute myocarditis with reduced viral load, attenuated inflammatory infiltrates determined by NKp46, F4/80 and CD3/CD4/CD8 expression and reduced IFNß, IFNγ, TNFα, IL-1ß and IL-12 levels. Moreover, myocardial injury assessed by necrotic lesions and troponin I release was attenuated resulting in preserved left ventricular function. Those changes were reversed by APN reconstitution. APN had no influence on adhesion, uptake or replication of CVB3 in cardiac myocytes. In acute CVB3 myocarditis, cardiac viral load did not differ between APN-KO and WT mice. However, APN-KO mice displayed an enhanced acute immune response, i.e. increased expression of myocardial CD14, IFNß, IFNγ, IL-12, and TNFα resulting in increased cardiac infiltration with pro-inflammatory M1 macrophages and activated NK cells. Up-regulation of cardiac CD14 expression, type I and II IFNs and inflammatory cell accumulation in APN-KO mice was inhibited by APN reconstitution. Our observations indicate that APN promotes CVB3 myocarditis by suppression of toll-like receptor-dependent innate immune responses, polarization of anti-inflammatory M2 macrophages and reduction of number and activation of NK cells resulting in attenuated acute anti-viral immune responses.

A distinct subgroup of cardiomyopathy patients characterized by transcriptionally active cardiotropic erythrovirus and altered cardiac gene expression.

Recent studies have detected erythrovirus genomes in the hearts of cardiomyopathy and cardiac transplant patients. Assessment of the functional status of viruses may provide clinically important information beyond detection of the viral genomes. Here, we report transcriptional activation of cardiotropic erythrovirus to be associated with strongly altered myocardial gene expression in a distinct subgroup of cardiomyopathy patients. Endomyocardial biopsies (EMBs) from 415 consecutive cardiac erythrovirus (B19V)-positive patients with clinically suspected cardiomyopathy were screened for virus-encoded VP1/VP2 mRNA indicating transcriptional activation of the virus, and correlated with cardiac host gene expression patterns in transcriptionally active versus latent infections, and in virus-free control hearts. Transcriptional activity was detected in baseline biopsies of only 66/415 patients (15.9 %) harbouring erythrovirus. At the molecular level, significant differences between cardiac B19V-positive patients with transcriptionally active versus latent virus were revealed by expression profiling of EMBs. Importantly, latent B19V infection was indistinguishable from controls. Genes involved encode proteins of antiviral immune response, B19V receptor complex, and mitochondrial energy metabolism. Thus, functional mapping of erythrovirus allows definition of a subgroup of B19V-infected cardiomyopathy patients characterized by virus-encoded VP1/VP2 transcripts and anomalous host myocardial transcriptomes. Cardiac B19V reactivation from latency, as reported here for the first time, is a key factor required for erythrovirus to induce altered cardiac gene expression in a subgroup of cardiomyopathy patients. Virus genome detection is insufficient to assess pathogenic potential, but additional transcriptional mapping should be incorporated into future pathogenetic and therapeutic studies both in cardiology and transplantation medicine.

Cardiac inflammation contributes to changes in the extracellular matrix in patients with heart failure and normal ejection fraction.

BACKGROUND: The pathophysiology of heart failure with normal ejection fraction (HFNEF) is still under discussion. Here we report the influence of cardiac inflammation on extracellular matrix (ECM) remodeling in patients with HFNEF. METHODS AND RESULTS: We investigated left ventricular systolic and diastolic function in 20 patients with HFNEF and 8 control patients by conductance catheter methods and echocardiography. Endomyocardial biopsy samples were also obtained, and ECM proteins as well as cardiac inflammatory cells were investigated. Primary human cardiac fibroblasts were outgrown from the endomyocardial biopsy samples to investigate the gene expression of ECM proteins after stimulation with transforming growth factor-ß. Diastolic dysfunction was present in the HFNEF patients compared with the control patients. In endomyocardial biopsy samples from HFNEF patients, we found an accumulation of cardiac collagen, which was accompanied by a decrease in the major collagenase system (matrix metalloproteinase-1) in the heart. Moreover, a subset of inflammatory cells, which expressed the profibrotic growth factor transforming growth factor-ß, could be documented in the HFNEF patients. Stimulation of primary human cardiac fibroblasts from HFNEF patients with transforming growth factor-ß resulted in transdifferentiation of fibroblasts to myofibroblasts, which produced more collagen and decreased the amount of matrix metalloproteinase-1, the major collagenase in the human heart. A positive correlation between cardiac collagen, as well as the amount of inflammatory cells, and diastolic dysfunction was evident and suggests a direct influence of inflammation on fibrosis triggering diastolic dysfunction. CONCLUSIONS: Cardiac inflammation contributes to diastolic dysfunction in HFNEF by triggering the accumulation of ECM.

Genomic expression profiling of human inflammatory cardiomyopathy (DCMi) suggests novel therapeutic targets.

The clinical phenotype of human dilated cardiomyopathy (DCM) encompasses a broad spectrum of etiologically distinct disorders. As targeting of etiology-related pathogenic pathways may be more efficient than current standard heart failure treatment, we obtained the genomic expression profile of a DCM subtype characterized by cardiac inflammation to identify possible new therapeutic targets in humans. In this inflammatory cardiomyopathy (DCMi), a distinctive cardiac expression pattern not described in any previous study of cardiac disorders was observed. Two significantly altered gene networks of particular interest and possible interdependence centered around the cysteine-rich angiogenic inducer 61 (CYR61) and adiponectin (APN) gene. CYR61 overexpression, as in human DCMi hearts in situ, was similarly induced by inflammatory cytokines in vascular endothelial cells in vitro. APN was strongly downregulated in DCMi hearts and completely abolished cytokine-dependent CYR61 induction in vitro. Dysbalance between the CYR61 and APN networks may play a pathogenic role in DCMi and contain novel therapeutic targets. Multiple immune cell-associated genes were also deregulated (e.g., chemokine ligand 14, interleukin-17D, nuclear factors of activated T cells). In contrast to previous investigations in patients with advanced or end-stage DCM where etiology-related pathomechanisms are overwhelmed by unspecific processes, the deregulations detected in this study occurred at a far less severe and most probably fully reversible disease stage.

Hypotensive mechanisms of amifostine.

Amifostine, a chemo- and radioprotective agent developed as adjunctive therapy for malignancies, induces hypotension after approximately 20% of patient administrations. This study examines the molecular mechanisms underlying hypotension induced by amifostine. Amifostine and its metabolite, WR-1065, induced dose-dependent hypotension in anesthetized rats that was not blocked by N(G)-methyl L arginine (L-NAME), an NO synthase inhibitor. WR-1065 but not amifostine induced concentration-dependent relaxation of isolated rat aortic rings in an endothelium-independent fashion. Relaxation was not associated with increases in cGMP or cAMP and could not be blocked by L-NAME or indomethacin. Similarly, neither amifostine or WR-1065 activated adenylyl, particulate guanylyl, or soluble guanylyl cyclases. WR-1065 relaxed rat aortic rings precontracted with norepinepherine, suggesting alpha-adrenergic blocking activity. However, neither amifostine nor WR-1065 altered the ability of prazosin or phentolamine to bind to alpha-adrenergic receptors. Further, WR-1065 had no effect on receptor-mediated increases in intracellular calcium in BAL 17 murine B lymphocytes in vitro. Thus, hypotension after administration of amifostine is mediated by WR-1065 and appears to result from direct relaxation of vascular smooth muscle. Smooth muscle relaxation induced by WR-1065 is not related to production of nitric oxide, prostaglandins, or cyclic nucleotides; alpha-adrenergic receptor antagonism; or interference with receptor-dependent increases in intracellular calcium. Administration of ephedrine, an efficacious adrenergic agonist, attenuated hypotension induced by amifostine in anesthetized rats and may be useful in alleviating hypotension associated with amifostine administration in patients.

Cardioprotective effect of insulin-like growth factor I in myocardial ischemia followed by reperfusion.

In the present study, the cardioprotective effects of insulin-like growth factor I (IGF-I) were examined in a murine model of myocardial ischemia reperfusion (i.e., 20 min + 24 hr). IGF-I (1-10 micrograms per rat) administered 1 hr prior to ischemia significantly attenuated myocardial injury (i.e., creatine kinase loss) compared to vehicle (P < 0.001). In addition, cardiac myeloperoxidase activity, an index of neutrophil accumulation, in the ischemic area was significantly attenuated by IGF-I (P < 0.001). This protective effect of IGF-I was not observed with des-(1-3)-IGF-I. Immunohistochemical analysis of ischemic-reperfused myocardial tissue demonstrated markedly increased DNA fragmentation due to programmed cell death (i.e., apoptosis) compared to nonischemic myocardium. Furthermore, IGF-I significantly attenuated the incidence of myocyte apoptosis after myocardial ischemia and reperfusion. Therefore, IGF-I appears to be an effective agent for preserving ischemic myocardium from reperfusion injury and protects via two different mechanisms--inhibition of polymorphonuclear leukocyte-induced cardiac necrosis and inhibition of reperfusion-induced apoptosis of cardiac myocytes.

Beneficial effects of oligotide, a novel oligodeoxyribonucleotide, in murine traumatic shock.

The effects of oligotide, an oligodeoxyribonucleotide analog, were investigated in an experimental model of traumatic shock. Pentobarbital-anesthetized rats subjected to Noble-Collip drum trauma and receiving only the vehicle (i.e., Krebs-Henseleit solution) developed a severe form of traumatic shock characterized by marked hypotension (61 +/- 6 mmHg), a survival time of 115 +/- 21 min, endothelial dysfunction, significant increases in plasma free amino-nitrogen concentration (p < .001) as well as elevated intestinal myeloperoxidase activity. In contrast, oligotide given intravenously (15 mg/kg bolus + 10 mg/kg/h infusion for 5 h) resulted in a significant prolongation of survival time to 209 +/- 31 min (p < .01), a significant and sustained increase in mean arterial blood pressure, a significant attenuation of plasma free amino-nitrogen concentration (p < .01), and intestinal myeloperoxidase activity (p < .05). Furthermore, oligotide significantly preserved superior mesenteric artery (SMA) endothelial function as seen by the relaxation response of isolated SMA rings to acetylcholine (71 +/- 5% vs. 36 +/- 5%, p < .01 compared to untreated trauma rats). Moreover, oligotide in a concentration-dependent manner attenuated unstimulated human neutrophil adherence to either thrombin or trauma-activated SMA endothelium in vitro (p < .001). Thus, our data suggest that the mechanism of the protective effect of oligotide in traumatic shock is improving endothelial function and diminishing neutrophil accumulation leading to reduced tissue injury.

Sialyl Lewisx-containing oligosaccharide exerts beneficial effects in murine traumatic shock.

We investigated the effects of a soluble sialyl Lewisx-containing oligosaccharide (SLex-OS) in a rat model of traumatic shock. Pentobarbital-anesthetized rats subjected to Noble-Collip drum trauma developed a shock state characterized by marked hypotension, a survival time of 85 +/- 15 min, significant increases in ileal myeloperoxidase (P < 0.01), and plasma free amino-nitrogen activities (P < 0.01). Treatment with SLex-OS (10 mg/kg) 10 min posttrauma prolonged survival time to 198 +/- 29 min (P < 0.01), significantly attenuated ileal myeloperoxidase activity (P < 0.01), and diminished the accumulation of plasma free amino-nitrogen (P < 0.01), drug vs. vehicle, respectively. Furthermore, endothelium-dependent relaxation to acetylcholine in superior mesenteric artery rings isolated from SLex-OS-treated shock rats was significantly preserved (70 +/- 6 vs. 40 +/- 5% relaxation). No beneficial effects were observed using a nonfucosylated control oligosaccharide. Moreover, addition of SLex-OS significantly inhibited unstimulated human polymorphonuclear neutrophil (PMN) adherence in vitro to trauma-activated superior mesenteric artery endothelium ex vivo (P < 0.001). Our results indicate that SLex-OS exerts beneficial effects in traumatic shock states by blocking selectin-mediated leukocyte-endothelium interaction, thus improving survival, attenuating intestinal PMN accumulation, and diminishing shock-induced tissue injury.