Cooperative actions of dexamethasone and LXA4 analogs. (A) Human whole blood aliquots were incubated with 100 nmol/L dexamethasone for 120 minutes in the presence of 15-R/S-methyl-LXA4 (5 μmol/L) for the last 30 minutes of incubation, as indicated, and then challenged with 1 μmol/L PAF for 30 minutes at 37°C. Adhesion molecule expression is presented as the percentage of control. Mean fluorescence intensity for L-selectin: control, 37 ± 3; PAF, 26 ± 4; CD18: control, 61 ± 4; PAF, 73 ± 7; n = 5; both P < .05. *P < .05; **P < .01 v control (untreated). L-selectin and CD18 expression on dexamethasone plus 15-R/S-methyl-LXA4–treated cells did not differ significantly from those of control. (B) Confluent HCAEC monolayers were cultured for 6 hours with LPS (1 μg/mL) in the presence of dexamethasone (DEX; 100 nmol/L), 15-R/S-methyl-LXA4, or 16-phenoxy-LXA4 (5 μmol/L). Neutrophils pretreated with dexa- methasone and/or LXA4 analogs as described for whole blood were added to activated HCAEC and then challenged with PAF (1 μmol/L). The results are expressed as the mean ± SEM of 5 experiments using neutrophils from different donors. *P < .05 vLPS-treated.
