%0 Journal Article %1 Nikolaev2007a %A Nikolaev, V. O. %A Boivin, V. %A Stork, S. %A Angermann, C. E. %A Ertl, G. %A Lohse, M. J. %A Jahns, R. %D 2007 %J J Am Coll Cardiol %K & Adrenergic Aged Autoantibodies/*analysis/drug Biological Energy Epitopes Failure/drug Female Fluorescence Heart Humans Male Markers/analysis Middle Reference Resonance Sensitivity Specificity Transfer/instrumentation/*methods Values and beta-1/antagonists beta-Antagonists/therapeutic effects inhibitors/*immunology therapy/*immunology use Receptor %N 5 %P 423-31 %T A novel fluorescence method for the rapid detection of functional beta1-adrenergic receptor autoantibodies in heart failure %U http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=17662395 %V 50 %X OBJECTIVES: This study sought to develop a rapid method for the detection of activating autoantibodies directed against the beta1-adrenoceptor (anti-beta1-Abs) in patients with heart failure. BACKGROUND: The anti-beta1-Abs are supposed to play a pathophysiological role in heart failure. However, there is no reliable method for their detection. With a complex screening strategy (enzyme-linked immunosorbent assay, immunofluorescence, cyclic adenosine monophosphate cAMP-radioimmunoassay) we have previously identified antibodies targeting the second extracellular beta1-receptor loop (anti-beta1-EC(II)) in 13% of patients with ischemic cardiomyopathy (ICM) and in 26% with dilated cardiomyopathy (DCM). METHODS: To detect anti-beta1-Abs, we measured beta1-receptor-mediated increases in intracellular cAMP by fluorescence resonance energy transfer using a highly sensitive cAMP sensor (Epac1-based fluorescent cAMP sensor). RESULTS: The immunoglobulin G (IgG) prepared from 77 previously antibody-typed patients (22 ICM/55 DCM) and 50 matched control patients was analyzed. The IgG from all 22 previously anti-beta1-EC(II)-positive patients (5 ICM/17 DCM) induced a marked cAMP increase, indicating receptor activation (49.8 +/- 4.2% of maximal isoproterenol-induced signal). The IgG from control patients and 32 previously anti-beta1-EC(II)-negative patients (17 ICM/15 DCM) did not significantly affect cAMP. Surprisingly, our technology detected anti-beta1-Abs in 23 DCM patients formerly judged antibody-negative, but their cAMP signals were generally lower (31.3 +/- 6.8%) than in the previous group. "Low"-activator anti-beta1-Abs were blocked preferentially by peptides corresponding to the first, and "high"-activator anti-beta1-Abs by peptides corresponding to the second beta1-extracellular loop. Beta-blockers alone failed to fully prevent anti-beta1-EC(II)-induced receptor activation, which could be achieved, however, by the addition of beta1-EC(II) peptides. CONCLUSIONS: Our novel method of detecting anti-beta1-Abs proved to be fast and highly sensitive. It also revealed an insufficient ability of beta-blockers to prevent anti-beta1-EC(II)-induced receptor activation, which opens new venues for the research on anti-beta1-Abs and eventual treatment options in heart failure.

@article{Nikolaev2007a, abstract = {OBJECTIVES: This study sought to develop a rapid method for the detection of activating autoantibodies directed against the beta1-adrenoceptor (anti-beta1-Abs) in patients with heart failure. BACKGROUND: The anti-beta1-Abs are supposed to play a pathophysiological role in heart failure. However, there is no reliable method for their detection. With a complex screening strategy (enzyme-linked immunosorbent assay, immunofluorescence, cyclic adenosine monophosphate [cAMP]-radioimmunoassay) we have previously identified antibodies targeting the second extracellular beta1-receptor loop (anti-beta1-EC(II)) in 13% of patients with ischemic cardiomyopathy (ICM) and in 26% with dilated cardiomyopathy (DCM). METHODS: To detect anti-beta1-Abs, we measured beta1-receptor-mediated increases in intracellular cAMP by fluorescence resonance energy transfer using a highly sensitive cAMP sensor (Epac1-based fluorescent cAMP sensor). RESULTS: The immunoglobulin G (IgG) prepared from 77 previously antibody-typed patients (22 ICM/55 DCM) and 50 matched control patients was analyzed. The IgG from all 22 previously anti-beta1-EC(II)-positive patients (5 ICM/17 DCM) induced a marked cAMP increase, indicating receptor activation (49.8 +/- 4.2% of maximal isoproterenol-induced signal). The IgG from control patients and 32 previously anti-beta1-EC(II)-negative patients (17 ICM/15 DCM) did not significantly affect cAMP. Surprisingly, our technology detected anti-beta1-Abs in 23 DCM patients formerly judged antibody-negative, but their cAMP signals were generally lower (31.3 +/- 6.8%) than in the previous group. "Low"-activator anti-beta1-Abs were blocked preferentially by peptides corresponding to the first, and "high"-activator anti-beta1-Abs by peptides corresponding to the second beta1-extracellular loop. Beta-blockers alone failed to fully prevent anti-beta1-EC(II)-induced receptor activation, which could be achieved, however, by the addition of beta1-EC(II) peptides. CONCLUSIONS: Our novel method of detecting anti-beta1-Abs proved to be fast and highly sensitive. It also revealed an insufficient ability of beta-blockers to prevent anti-beta1-EC(II)-induced receptor activation, which opens new venues for the research on anti-beta1-Abs and eventual treatment options in heart failure.}, added-at = {2010-12-14T18:12:02.000+0100}, author = {Nikolaev, V. O. and Boivin, V. and Stork, S. and Angermann, C. E. and Ertl, G. and Lohse, M. J. and Jahns, R.}, biburl = {https://www.bibsonomy.org/bibtex/2e8ec9843465f59be295c932409d6d40b/pharmawuerz}, endnotereftype = {Journal Article}, interhash = {ef9d1f15562a5fef80622c8bff68928b}, intrahash = {e8ec9843465f59be295c932409d6d40b}, issn = {1558-3597 (Electronic) 1558-3597 (Linking)}, journal = {J Am Coll Cardiol}, keywords = {& Adrenergic Aged Autoantibodies/*analysis/drug Biological Energy Epitopes Failure/drug Female Fluorescence Heart Humans Male Markers/analysis Middle Reference Resonance Sensitivity Specificity Transfer/instrumentation/*methods Values and beta-1/antagonists beta-Antagonists/therapeutic effects inhibitors/*immunology therapy/*immunology use Receptor}, month = {Jul 31}, note = {Nikolaev, Viacheslav O Boivin, Valerie Stork, Stefan Angermann, Christiane E Ertl, Georg Lohse, Martin J Jahns, Roland Comparative Study Research Support, Non-U.S. Gov't United States Journal of the American College of Cardiology J Am Coll Cardiol. 2007 Jul 31;50(5):423-31. Epub 2007 Jul 13.}, number = 5, pages = {423-31}, shorttitle = {A novel fluorescence method for the rapid detection of functional beta1-adrenergic receptor autoantibodies in heart failure}, timestamp = {2010-12-14T18:22:41.000+0100}, title = {A novel fluorescence method for the rapid detection of functional beta1-adrenergic receptor autoantibodies in heart failure}, url = {http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=17662395}, volume = 50, year = 2007 }