Association of Glucocorticoids and Cyclosporin a or Rapamycin Prevents E-Selectin and Il-8 Expression During LPS- And Tnf??-Mediated Endothelial Cell Activation1

BACKGROUND: Endothelial cell (EC) activation plays an important role in inflammation, hemostasis, and organ rejection of allogeneic and xenogeneic transplantation. These processes leads to rapid and transient up-regulation of proinflammatory molecules, such as the adhesion molecule E-selectin and the chemotactic cytokine IL-8. The purpose of this study was to investigate the specific effects of several major and potentially synergistic immunosuppressive drugs-cyclosporin A (CsA), rapamycin (Rap), and glucocorticoids (GC)-on lipopolysaccharide (LPS)- or tumor necrosis factor (TNF)alpha-induced EC activation METHODS: The ability of immunosuppressive drugs, used alone or in combination, to prevent in vitro TNFalpha- and LPS-induced expression of E-selectin and interleukin 8 on porcine ECs, as well as their effect on leukocyte-EC interaction, were investigated. In addition, we studied the in vivo effect of these drugs after i.v. administration of recombinant TNFalpha to rats. RESULTS: At high concentrations, which correspond to the acceptable experimental levels in primate xenograft recipients, CsA, Rap, and GC individually inhibited E-selectin protein induction in a dose-dependent manner in cultured porcine ECs treated with LPS with an additive effect when the drugs were associated. The pattern of drug-mediated inhibition was related to the stimulus used to activate ECs (i.e., LPS vs. TNFalpha). Reduced expression of E-selectin on ECs activated in the presence of the tested immunosuppressive drugs correlated with a weaker adhesion of human U937 cells to ECs. Messenger RNA analysis demonstrated that the presence of CsA, Rap, and GC during EC activation inhibited E-selectin and interleukin 8 at the gene expression level. LPS-mediated induction of IbetaBalpha expression was not observed in ECs treated with CsA, whereas GC reduced its transcripts by approximately 50%. It is interesting that in vivo studies confirmed that CsA and GC inhibited EC activation at therapeutic doses (1 mg/kg and 10 mg/kg for GC and CsA, respectively) and showed that the combination of CsA and GC efficiently prevents TNFalpha-mediated induction of E-selectin on cardiac ECs. CONCLUSION: Our data show that, besides their specific immunosuppressive effects on T cells, CsA, Rap, and GC can efficiently contribute to the attenuation of EC activation in vivo and the resulting inhibition is enhanced by the association of CsA with GC.