INOTROPES INHIBIT ENDOTHELIAL-CELL SURFACE-ADHESION MOLECULES INDUCEDBY INTERLEUKIN-1-BETA

Objectives: Leukocyte-endothelial cell interactions play a critical ro le in sepsis-induced multiple organ system failure and acute respirato ry distress syndrome. Increased cyclic adenosine 3',5'-monophosphate ( cAMP) has been previously reported to inhibit expression of the cytoki ne stimulated endothelial cell adhesion molecules, E-selectin, and vas cular cell adhesion molecule-1 (VCAM-1). We hypothesized that clinical ly relevant concentrations of inotropes, such as amrinone and dopamine , which increase cAMP, could inhibit cytokine-stimulated upregulation of endothelial adhesion proteins. Design: Prospective, controlled in v itro study. Setting: Leukocyte biology laboratory. Subjects: Human umb ilical vein endothelial cells isolated from neonatal umbilical cord sp ecimens and whole blood obtained from normal human adult volunteers we re used in this study. Interventions: Endothelial cell monolayers were pretreated with increasing concentrations of amrinone or dopamine, or left untreated as controls, followed by exposure to recombinant human interleukin (IL)-1 beta for 6 hrs. Monolayers were then incubated wit h monoclonal antibodies to E-selectin, VCAM-1, and intercellular adhes ion molecule-1 (ICAM-1), fluorescence labeled, and assessed for mean f luorescence intensity by flow cytometry as a measure of surface adhesi on molecule concentrations. Whole blood neutrophils were pretreated wi th or without inotropes, then stimulated with n-formyl methyl leucine phenylalanine. Stimulated neutrophils were incubated with antibodies a gainst the neutrophil adherence protein CD11b and assessed by flow cyt ometry. Measurements and Main Results: IL-1 beta markedly increased E- selectin (p =.01), VCAM-1 (p < .01), and ICAM-1 (p <.001) concentratio ns (n = 6). Pretreatment with amrinone significantly decreased endothe lial E-selectin surface Values at all concentrations (p < .001 by anal ysis of variance, n = 5), including therapeutic concentration ranges. Amrinone also inhibited upregulation of ICAM-1 (p <.001) at therapeuti c concentrations, and VCAM-1 (p <.001) at higher concentrations. Dopam ine inhibited only E-selectin at relevant concentrations. Neutrophil p retreatment with inotropes did not prevent CD11b upregulation. Conclus ions: Pretreatment with amrinone, and to a lesser degree, with dopamin e, at clinically relevant concentrations inhibits in vitro IL-1 alpha- induced increases in human umbilical Vein endo thelia[ cell adhesion m olecule concentrations. Future studies are necessary to investigate th e mechanisms of these effects and to determine in vivo efficacy of ino tropes as anti-inflammatory agents.