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Background: In patients suffering from dilated cardiomyopathy (DCM), immunoadsorption with subsequent IgG substitution (IA/IgG) leads to an acute and prolonged improvement of hemodynamics and heart failure symptoms. However, some patients receiving IA/IgG experience recurrence of heart failure after an initial benefit. The aim of this study was to investigate whether a second IA/IgG treatment episode improves left ventricular systolic function and further mitigates heart failure symptoms in these patients. Methods: We retrospectively analyzed 15 DCM patients who experienced a significant improvement of LVEF (≥ 5% absolute or ≥ 20% relative) and heart failure symptoms (≥ 1 NYHA functional class) but a subsequent deterioration (decline in LVEF ≥ 5% absolute or ≥ 20% relative and NYHA worsening ≥1 class) after the first IA/IgG. These patients underwent a second IA/IgG treatment 41.7 ± 27.4 months after the first cycle. Follow up data were acquired 3-6 months after both IA/IgG treatments. Results: The first IA/IgG induced an improvement of LVEF from 33 ± 6.4% to 43.2 ± 7.9% ( P < 0.001) and of mean NYHA functional class from 2.9 ± 0.26 to 1.8 ± 0.56 ( P < 0.001). The second treatment was associated with a significant improvement in LVEF (from 29.7 ± 4.6% to 34.9 ± 8.3%, P = 0.013) and NYHA functional class (2.87 ± 0.64 to 2.33 ± 0.72; P = 0.02). This improvement was less pronounced compared to the first treatment with respect to both, LVEF ( P = 0.09) and NYHA improvement ( P = 0.04). Conclusion: In DCM patients, who experience a significant improvement of LVEF and heart failure symptoms after IA/IgG but a subsequent relapse during follow up, repeated IA/IgG may be considered. J. Clin. Apheresis 30:217-223, 2015. © 2014 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Aims Autoantibodies against second extracellular loops of β1-adrenergic receptors frequent in dilated cardiomyopathy confer myocardial dysfunction presumably via cAMP stimulation. Here, we investigate the autoantibody impact on receptor conformation and function. Methods and results IgG was prepared from patients with dilated cardiomyopathy, matched healthy donors (10 each) or commercial IgG preparations (2). IgG binding to β1-adrenergic receptor peptides was detected in 5 of 10 patients and 2 of 10 controls. IgG colocalization with the native receptor was detected in 8 of 10 patients and 1 of 10 controls (10 of 10 patients and 7 of 10 controls at >30 mg IgG/L). All IgGs exhibiting receptor colocalization triggered changes in receptor conformation (determined with fluorescent sensors) not stringently correlated to cAMP stimulation, suggesting the induction of more or less active receptor conformations. Receptor-activating IgG was detected in 8 of 10 patients but only 1 of 10 controls. In addition, IgG from 8 of 10 patients and 3 of 10 controls attenuated receptor internalization (measured by total internal reflection fluorescence microscopy). IgG-inducing inactive receptor conformations had no effect on subsequent cAMP stimulation by isoproterenol. IgG-inducing active receptor conformations dampened or augmented subsequent cAMP stimulation by isoproterenol, depending on whether receptor internalization was attenuated or not. Corresponding IgG effects on the basal beating rate and chronotropic isoproterenol response of embryonic human cardiomyocytes were observed. Conclusions (i) Autoantibodies trigger conformation changes in the β1-adrenergic receptor molecule. (ii) Some also attenuate receptor internalization. (iii) Combinations thereof increase the basal beating rate of cardiomyocytes and optionally entail dampening of their chronotropic catecholamine responses. (iv) The latter effects seem specific for patient autoantibodies, which also have higher levels. [ABSTRACT FROM AUTHOR]

Aims Immunoadsorption with subsequent immunoglobulin G substitution (IA/IgG) represents a novel therapeutic approach in the treatment of dilated cardiomyopathy (DCM) which leads to the improvement of left ventricular ejection fraction (LVEF). However, response to this therapeutic intervention shows wide inter-individual variability. In this pilot study, we tested the value of clinical, biochemical, and molecular parameters for the prediction of the response of patients with DCM to IA/IgG. Methods and results Forty DCM patients underwent endomyocardial biopsies (EMBs) before IA/IgG. In eight patients with normal LVEF (controls), EMBs were obtained for clinical reasons. Clinical parameters, negative inotropic activity (NIA) of antibodies on isolated rat cardiomyocytes, and gene expression profiles of EMBs were analysed. Dilated cardiomyopathy patients displaying improvement of LVEF (≥20 relative and ≥5% absolute) 6 months after IA/IgG were considered responders. Compared with non-responders (n = 16), responders (n = 24) displayed shorter disease duration (P = 0.006), smaller LV internal diameter in diastole (P = 0.019), and stronger NIA of antibodies. Antibodies obtained from controls were devoid of NIA. Myocardial gene expression patterns were different in responders and non-responders for genes of oxidative phosphorylation, mitochondrial dysfunction, hypertrophy, and ubiquitin–proteasome pathway. The integration of scores of NIA and expression levels of four genes allowed robust discrimination of responders from non-responders at baseline (BL) [sensitivity of 100% (95% CI 85.8–100%); specificity up to 100% (95% CI 79.4–100%); cut-off value: −0.28] and was superior to scores derived from antibodies, gene expression, or clinical parameters only. Conclusion Combined assessment of NIA of antibodies and gene expression patterns of DCM patients at BL predicts response to IA/IgG therapy and may enable appropriate selection of patients who benefit from this therapeutic intervention. [ABSTRACT FROM PUBLISHER]

Eur J Clin Invest 2010; 40 (8): 685–691 Background Disturbances of humoral immunity have been described in dilated cardiomyopathy (DCM), and a number of antibodies against cardiac cell proteins have been identified. Previous studies showed that immunoadsorption therapy with subsequent IgG substitution (IA/IgG) enhances cardiac function, and that removal of cardiodepressant antibodies may represent one essential mechanism of this therapy. The long-term effect of IA/IgG on the level of cardiodepressant antibodies remains to be elucidated. Methods A total of 17 patients with DCM were observed up to 12 months after IA/IgG. Echocardiographic measurements were performed at baseline, 3, 6 and 12 months after therapy. Cardiodepressant antibodies were detected by incubation of rat cardiomyocytes with purified patients’ IgG and recording of contractility and Ca2+ ratio. Results In contrast to patients without cardiodepressant antibodies before IA/IgG, patients with negative inotropic antibodies showed an improvement of left ventricular ejection fraction (LVEF) from 33·8 ± 1·7% to 44·7 ± 2·7%; 44·5 ± 2·3% and 51·8 ± 1·7% after 3, 6 and 12 months ( P < 0·001 vs. baseline, P < 0·05 vs. LVEF of non-cardiodepressant group). Immediately after IA/IgG therapy, no cardiodepressant effects of patients’ IgG on isolated cardiomyocytes were detectable, and this effect remained diminished until 6 months after IA/IgG ( P < 0·001 for contractility and Ca2+ ratio). Compared with the levels after 3 and 6 months, cardiodepressant antibodies reoccured after 12 months ( P = 0·067 for contractility, P < 0·05 for Ca2+ ratio vs. 6 months after IA/IgG). However, the negative inotropic reaction is still diminished compared with the reaction before IA/IgG. Conclusion IA/IgG therapy induces long-term reduction of negative inotropic antibodies. After 12 months, however, re-increase of negative inotropic antibodies cannot be excluded. [ABSTRACT FROM AUTHOR]

Abstract: Background: The role of melusin, a necessary component in pressure-induced left-ventricular hypertrophy (LVH) in mice, has not yet been determined in human cardiac hypertrophy. We analyzed for the first time the expression and regional distribution of melusin in human LVH due to aortic stenosis (AS) and determined AKT phosphorylation as a potential downstream effector of melusin signalling. Methods: Regional distribution of melusin was evaluated in four normal hearts. Melusin staining, gene expression and protein content were assessed in biopsies from normal and diseased hearts and melusin gene expression was correlated with LV functional changes. The pAKT/AKT ratio was determined in parallel and correlated with melusin protein content. Results: In normal hearts, melusin was found in the myocytes with a uniform regional distribution. Melusin staining, mRNA and protein were significantly decreased in human AS hearts. The reduction in melusin mRNA was significantly correlated with LVEF, LVEDD and LVESD. pAKT/AKT ratio was significantly decreased in human AS and was correlated with melusin content. Conclusion: Reduction in melusin expression parallels the functional cardiac impairment in human AS. The simultaneous decrease of melusin and AKT phosphorylation suggests a connection between the loss of melusin and the decrease in systolic function. [Copyright &y& Elsevier]