title: Ramipril and metoprolol intake aggravate human and murine anaphylaxis: evidence for direct mast cell priming.
abstract: BACKGROUND
  Cofactors contribute to the elicitation of anaphylaxis. β-Blockers and angiotensin-converting enzyme (ACE) inhibitors are widely used cardiovascular drugs. We specially designed a mouse model to further analyze the cofactor potential of these drugs.
  
  
  OBJECTIVE
  We sought to test the hypothesis that β-blockers and ACE inhibitors alter the risk for severe anaphylaxis and to pinpoint the associated mechanism.
  
  
  METHODS
  The risk factor potency of cardiovascular drugs on the severity of anaphylaxis in patients from German-speaking countries was analyzed. In vivo interaction of the cardiovascular drugs metoprolol (β-blocker) and ramipril (ACE inhibitor) with the anaphylactic response was determined. Mast cell (MC) mediators (histamine, serotonin, leukotriene C₄, prostaglandin D2, and mouse mast cell protease 1) were quantified in serum. Bone marrow-derived cultured MCs served to identify whether the therapeutics targeted MCs directly.
  
  
  RESULTS
  Our anaphylaxis database indicated a higher risk of severe anaphylaxis after monotherapy with β-blockers or ACE inhibitors, which was more pronounced when both drugs were combined. This was confirmed in our mouse model. While single therapeutics had either no significant (ramipril) or a modestly aggravating (metoprolol) effect, their combined administration exacerbated anaphylactic symptoms potently and simultaneously enhanced MC mediators, hinting at MCs as direct targets. In fact, FcεRI-mediated MC histamine release was synergistically increased by metoprolol/ramipril or metoprolol/bradykinin (the latter increased after ACE inhibitor intake), whereas the substances had no significant effect on their own. MC priming was particularly pronounced when FcεRI aggregation was in the suboptimal range, reflecting common clinical settings.
  
  
  CONCLUSIONS
  β-Blockers and ACE inhibitors synergistically aggravate anaphylaxis at least partly by decreasing the threshold of MC activation.
authors.affiliation: Allergy Center Charité, CCM, Department of Dermatology and Allergology, Charité-Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: Maria
authors.initials: M
authors.lastname: Nassiri
authors.affiliation: Allergy Center Charité, CCM, Department of Dermatology and Allergology, Charité-Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: Magda
authors.initials: M
authors.lastname: Babina
authors.affiliation: Allergy Center Charité, CCM, Department of Dermatology and Allergology, Charité-Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: Sabine
authors.initials: S
authors.lastname: Dölle
authors.affiliation: Edenharter Research, Berlin, Germany.
authors.forename: Günter
authors.initials: G
authors.lastname: Edenharter
authors.affiliation: Department of Dermatology and Allergology, Ludwig-Maximilians-Universität, Munich, Germany.
authors.forename: Franziska
authors.initials: F
authors.lastname: Ruëff
authors.affiliation: Allergy Center Charité, CCM, Department of Dermatology and Allergology, Charité-Universitätsmedizin Berlin, Berlin, Germany. Electronic address: Margitta.worm@charite.de.
authors.forename: Margitta
authors.initials: M
authors.lastname: Worm
mesh_terms: D058671:Adrenergic beta-1 Receptor Antagonists / Q000008:administration & dosage / Q000009:adverse effects*; D000328:Adult; D000707:Anaphylaxis / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology*; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000008:administration & dosage / Q000009:adverse effects*; D000818:Animals; D000959:Antihypertensive Agents / Q000008:administration & dosage / Q000009:adverse effects; D002648:Child; D004305:Dose-Response Relationship, Drug; D004359:Drug Therapy, Combination; D005260:Female; D006636:Histamine Release; D006801:Humans; D007073:Immunoglobulin E / Q000276:immunology; D018836:Inflammation Mediators / Q000378:metabolism; D008297:Male; D008407:Mast Cells / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D008790:Metoprolol / Q000008:administration & dosage / Q000009:adverse effects*; D051379:Mice; D017257:Ramipril / Q000008:administration & dosage / Q000009:adverse effects*; D012042:Registries; D012306:Risk; D012720:Severity of Illness Index
chemical_list: D058671:Adrenergic beta-1 Receptor Antagonists; D000806:Angiotensin-Converting Enzyme Inhibitors; D000959:Antihypertensive Agents; D018836:Inflammation Mediators; D007073:Immunoglobulin E; D008790:Metoprolol; D017257:Ramipril
keywords: Anaphylaxis; angiotensin-converting enzyme inhibitor; cardiovascular medication; cofactor; mast cells; β-blocker