title: The nondepolarizing, normokalemic cardioplegia formulation adenosine-lidocaine (adenocaine) exerts anti-neutrophil effects by synergistic actions of its components.
abstract: OBJECTIVE
  A new strategy of normothermic cardioplegia based on the combination of adenosine and lidocaine (adenocaine; Hibernation Therapeutics Global Ltd, Kilquade, Ireland) achieves nondepolarized arrest at normokalemia. Both adenosine and lidocaine independently inhibit neutrophil (polymorphonuclear neutrophil; PMN) activity. However, whether adenocaine exerts greater anti-inflammatory effects is not known. We tested the hypothesis that adenocaine synergistically attenuates PMN functions.
  
  
  METHODS
  Superoxide anion (O(2)(-)) generation: Isolated porcine PMNs were primed with cytochalasin B (5 μg/mL) and activated by N-formylmethionyl-leucyl-phenylalanine (100 nM). O(2)(-) release was quantified using lucigenin-enhanced chemiluminescence. Data were expressed as percent of stimulated control.
  
  
  RESULTS
  Both adenosine and lidocaine alone inhibited O(2)(-) production in a dose-dependent manner (adenosine reduced to 67% ± 8.4% and 21% ± 2.2% of maximal stimulation at 0.1 and 10 μmol/L, respectively, lidocaine reduced to 57.9% ± 18.6% and 28% ± 5% at 10 and 100 μmol/L, respectively). Adenocaine further reduced O(2)(-) generation in a synergistic manner. In addition, adenosine alone (0.1-10 μmol/L) inhibited O(2)(-) generation in primed but not activated PMNs, whereas lidocaine alone (1-100 μmol/L) inhibited O(2)(-) release in both primed and activated PMNs. Adenocaine further reduced O(2)(-) generation because of inhibition of both priming and activation stages. Both adenosine and lidocaine alone and adenocaine comparably inhibited platelet activating factor-induced CD11 b/c surface expression on PMNs (flow cytometry), but adenocaine further suppressed both CD18 expression (to 47.4% ± 9.7%) and PMN adherence (to 47.2% ± 4.3%) compared with adenosine and lidocaine alone. Transmigration of calcein-acetyoxymethyl-labeled PMNs through transwells seeded with cultured coronary artery endothelial cells was reduced comparably by adenosine (to 80.1% ± 6.7%) and adenocaine (67.3% ± 9.6%).
  
  
  CONCLUSIONS
  Adenocaine suppresses multiple PMN functions including O(2)(-) generation, adhesion molecule expression, PMN adherence, and transmigration. In addition to inducing nondepolarized arrest, adenocaine cardioplegia may exert cardioprotection by inhibiting PMN-mediated inflammatory responses.
authors.affiliation: Cardiothoracic Research Laboratory, Carlyle Fraser Heart Center, Emory University, 550 Peachtree Street NE, Atlanta, GA 30308-2225, USA.
authors.forename: Weiwei
authors.initials: W
authors.lastname: Shi
authors.forename: Rong
authors.initials: R
authors.lastname: Jiang
authors.forename: Geoffrey P
authors.initials: GP
authors.lastname: Dobson
authors.forename: Asger
authors.initials: A
authors.lastname: Granfeldt
authors.forename: Jakob
authors.initials: J
authors.lastname: Vinten-Johansen
mesh_terms: D000241:Adenosine / Q000494:pharmacology*; D000779:Anesthetics, Local / Q000494:pharmacology*; D000818:Animals; D018845:CD11 Antigens / Q000378:metabolism; D018821:CD18 Antigens / Q000378:metabolism; D002314:Cardioplegic Solutions / Q000494:pharmacology*; D002448:Cell Adhesion / Q000187:drug effects; D002478:Cells, Cultured; D018920:Coculture Techniques; D003331:Coronary Vessels / Q000187:drug effects / Q000276:immunology; D003571:Cytochalasin B / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004338:Drug Combinations; D004357:Drug Synergism; D005434:Flow Cytometry; D008012:Lidocaine / Q000494:pharmacology*; D008163:Luminescent Measurements; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D018375:Neutrophil Activation / Q000187:drug effects*; D009504:Neutrophils / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism; D010972:Platelet Activating Factor / Q000378:metabolism; D013481:Superoxides / Q000378:metabolism; D013552:Swine; D013997:Time Factors; D057705:Transendothelial and Transepithelial Migration / Q000187:drug effects
chemical_list: D000779:Anesthetics, Local; D018845:CD11 Antigens; D018821:CD18 Antigens; D002314:Cardioplegic Solutions; D004338:Drug Combinations; D010972:Platelet Activating Factor; C572495:adenocaine; D013481:Superoxides; D003571:Cytochalasin B; D009240:N-Formylmethionine Leucyl-Phenylalanine; D008012:Lidocaine; D000241:Adenosine