Pharmacological characterisation of the interaction between glycopyrronium bromide and indacaterol fumarate in human isolated bronchi, small airways and bronchial epithelial cells.
Nowadays, there is a considerable gap in knowledge concerning the mechanism(s) by which long-acting β2-agonists (LABAs) and long-acting muscarinic antagonists (LAMAs) interact to induce bronchodilation. This study aimed to characterise the pharmacological interaction between glycopyrronium bromide and indacaterol fumarate and to identify the mechanism(s) leading to the bronchorelaxant effect of this interaction.



The effects of glycopyrronium plus indacaterol on the contractile tone of medium and small human isolated bronchi were evaluated, and acetylcholine and cAMP concentrations were quantified. The interaction was assessed by Bliss Independence approach.



Glycopyrronium plus indacaterol synergistically inhibited the bronchial tone (medium bronchi, +32.51 % ± 7.86 %; small bronchi, +28.46 % ± 5.35 %; P < 0.05 vs. additive effect). The maximal effect was reached 140 min post-administration. A significant (P < 0.05) synergistic effect was observed during 9 h post-administration on the cholinergic tone, but not on the histaminergic contractility. Co-administration of glycopyrronium and indacaterol reduced the release of acetylcholine from the epithelium but not from bronchi, and enhanced cAMP levels in bronchi and epithelial cells (P < 0.05 vs. control), an effect that was inhibited by the selective KCa(++) channel blocker iberiotoxin. The role of cAMP-dependent pathway was confirmed by the synergistic effect elicited by the adenylate cyclase activator forskolin on glycopyrronium (P < 0.05 vs. additive effect), but not on indacaterol (P > 0.05 vs. additive effect), with regard of the bronchial relaxant response and cAMP increase.



Glycopyrronium/indacaterol co-administration leads to a synergistic improvement of bronchodilation by increasing cAMP concentrations in both airway smooth muscle and bronchial epithelium, and by decreasing acetylcholine release from the epithelium.
Department of Systems Medicine, Chair of Respiratory Medicine, University of Rome Tor Vergata, Rome, Italy.|Department of Systems Medicine, Respiratory Pharmacology Research Unit, University of Rome Tor Vergata, Via Montpellier 1, 00133, Rome, Italy.|Division of Respiratory Medicine, University Hospital Tor Vergata, Rome, Italy.
Mario
M
Cazzola
Department of Systems Medicine, Respiratory Pharmacology Research Unit, University of Rome Tor Vergata, Via Montpellier 1, 00133, Rome, Italy. luigino.calzetta@uniroma2.it.
Luigino
L
Calzetta
Department of Systems Medicine, Chair of Respiratory Medicine, University of Rome Tor Vergata, Rome, Italy.|Division of Respiratory Medicine, University Hospital Tor Vergata, Rome, Italy.
Ermanno
E
Puxeddu
Division of Respiratory Medicine, University Hospital Tor Vergata, Rome, Italy.
Josuel
J
Ora
Regina Elena National Cancer Institute, Thoracic Surgery Unit, Rome, Italy.
Francesco
F
Facciolo
Department of Systems Medicine, Chair of Respiratory Medicine, University of Rome Tor Vergata, Rome, Italy.|Division of Respiratory Medicine, University Hospital Tor Vergata, Rome, Italy.
Paola
P
Rogliani
Department of Experimental Medicine, Unit of Pharmacology, Second University of Naples, Naples, Italy.
Maria Gabriella
MG
Matera
D000109:Acetylcholine / Q000378:metabolism; D000262:Adenylyl Cyclases / Q000378:metabolism; D058666:Adrenergic beta-2 Receptor Agonists / Q000494:pharmacology*; D000368:Aged; D001980:Bronchi / Q000187:drug effects* / Q000378:metabolism; D016084:Bronchoconstriction / Q000187:drug effects*; D001993:Bronchodilator Agents / Q000494:pharmacology*; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D004847:Epithelial Cells / Q000187:drug effects* / Q000378:metabolism; D005260:Female; D006024:Glycopyrrolate / Q000494:pharmacology*; D006801:Humans; D066298:In Vitro Techniques; D007189:Indans / Q000494:pharmacology*; D008297:Male; D008875:Middle Aged; D018727:Muscarinic Antagonists / Q000494:pharmacology*; D061251:Primary Cell Culture; D015363:Quinolones / Q000494:pharmacology*; D013997:Time Factors
D058666:Adrenergic beta-2 Receptor Agonists; D001993:Bronchodilator Agents; D007189:Indans; D018727:Muscarinic Antagonists; D015363:Quinolones; C510790:indacaterol; D000242:Cyclic AMP; D000262:Adenylyl Cyclases; D000109:Acetylcholine; D006024:Glycopyrrolate
Glycopyrronium bromide; Human bronchi; Indacaterol fumarate; Synergistic interaction