Association of glucocorticoids and cyclosporin A or rapamycin prevents E-selectin and IL-8 expression during LPS- and TNF alpha-mediated endothelial cell activation

Background. Endothelial cell (EC) activation plays an important role ill in flammation, hemostasis, and organ rejection of allogeneic and xenogeneic tr ansplantation These processes leads to rapid and transient up-regulation of I,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 immunosu ppressive drugs-cyclosporin A (CsA), rapamycin (Rap), and glucocorticoids ( GC)-on lipopolysaccharide (LPS)- or tumor necrosis factor (TNF)alpha-induce d EC activation Methods. The ability of immunosuppressive drugs, used alone or in combinati on, to prevent in vitro TNF alpha- and LPS-induced expression of E-selectin and interleukin 8 on porcine I:Cs, 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 TNF alpha to rats. Results. At high concentrations, which correspond to the acceptable experim ental levels in primate xeno-graft recipients, CsA, Rep, and GC individuall y inhibited E-selectin protein induction in a dose-dependent manner in cult ured porcine ECs treated with LPS with an additive effect when the drugs we re associated. The pattern of drug mediated inhibition was related to the s timulus used to activate ECs (i.e., LPS vs. TNF alpha). Reduced expression of E-selectin on ECs activated in the presence of the tested immunosuppress ive drugs correlated with a weaker adhesion of human U937 cells to ECs, Mes senger RNA analysis demonstrated that the presence of CsA, Rep, and GC duri ng EC activation inhibited E-selectin and interleukin 8 at the gene express ion level. LPS-mediated induction of I kappa B alpha expression was not obs erved in ECs treated with CsA, whereas GC reduced its transcripts by approx imately 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 G C and CsA, respectively) and showed that the combination of CsA and GC effi ciently prevents TNF alpha-mediated induction of E-selectin on cardiac ECs, Conclusion. Our data show that, besides their specific immunosuppressive ef fects on T cells, CsA, Rep, and GC can efficiently contribute to the attenu ation of EC activation in vivo and the resulting inhibition is enhanced by the association of CsA with GC.