Activating beta-1-adrenoceptor antibodies are not associated with cardiomyopathies secondary to valvular or hypertensive heart disease
Roland Jahns, MD*,
Valérie Boivin, PhD ,
Christian Siegmund, MD,
Fritz Boege, MD*,
Martin J. Lohse, MD and
Gerhard Inselmann, MD*
* Department of Internal Medicine, Medizinische Poliklinik, University of Wuerzburg, Wuerzburg, Germany
Department of Pharmacology, University of Wuerzburg, Wuerzburg, Germany
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Figure 1 Screening of patients with VHD or HHD, or healthy controls (Healthy) for anti-beta-AR autoantibodies. (Left) Increased reactivity in ELISA with synthetic peptides corresponding to the aminoterminal (N), second extracellular (ECII), or carboxyterminal (C) domains of human beta-1- (open bars), or beta-2- (closed bars), or both receptor subtypes (hatched bars). (Right) Sera specifically recognizing receptor peptides selected for binding (IFM = indirect fluorescence microscopy, see Fig. 2) and functional interaction (increase in cAMP, see Fig. 3) with intact human beta-AR. Bars represent the number of positive results for each epitope; numbers in parentheses (on top of the bars) indicate cross-reactions with another receptor domain. The total number of autoantibody-positive individuals is given underneath each diagram (brackets).
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Figure 2 Detection of anti-beta-AR antibodies by immunofluorescence microscopy. Intact native Sf9 cells expressing recombinant human beta-AR (ß1/ß2), or infected with wild-type vector (W) were probed with subtype-specific anti-beta-AR rabbit antibodies (5) (Rabbit, anti-ß1/ß2), with IgG from an antibody-negative healthy subject (Healthy), or with IgG from a patient with chronic valvular and concomitant ischemic heart disease recognizing only the beta-1-AR (VHD), or a patient with hypertensive heart disease and concomitant collagenosis recognizing both beta-AR bearing Sf9 cells and wild-type virus-infected control cells (nonspecific staining, HHD).
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Figure 3 cAMP-levels of CHW-beta-1 cells upon incubation with different patient IgG preparations. The cells were stimulated with 10 µmol/liter (–) isoproterenol (hatched bars) or not (black bars) either (a: left) (error bars: ± SD) in the absence (Controls) or presence of IgG fractions from antibody-negative control subjects (Healthy, negatives), or (b: right) (error bars: ± SD of three independent experiments) after preincubation with immunofluorescence-positive IgG fractions from an HHD patient also staining Sf9 control cells (left), a VHD patient with concomitant ICM (middle) and the only positive control subject (right). Significant differences compared with antibody-negative healthy individuals are denoted by (*)p < 0.1, *p < 0.05 and **p < 0.001 (Scheffé’s F-test, post-hoc multiple comparison).
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