Deaggregators inhibit TNF-α-induced leukocyte adhesion in vitro by breaking up hydrophobic lipophilic interactions

Aim: Deaggregators (deAgrs) are nontoxic organic molecules that possess the ability to deaggregate simple aggregates formed by hydrophobic lipophilic interactions (HLI). Since HLI-driven organic molecule aggregates may induce leukocyte adhesion, we investigated the influence of deAgrs on TNF-alpha-mediated leukocyte adhesion in vitro. Methods: For adhesion studies, vascular endothelial cells or smooth muscle cells monolayers were treated with TNF-alpha (10 mu g/L) and deAgrs for 24 h, followed by addition of monocytes or neutrophils suspension. The non-adherent leukocytes were rinsed, and the number of attached leukocytes was measured using an ELISA plate reader. Simultaneously, fluorescence probes Np-12 and Np-Ch were used to measure the deaggregating efficiencies of these deAgrs. Results: Among the nine deAgrs tested,eight significantly reduced the cell adhesion rates with the order of efficiencies: 260>160>568>ZPMOP>R68>640>TB6PMOP>CNS, but TBHQ had no effect. The deAgrs for deaggregating an aggregated probe (Np-12 or Np-Ch) exhibited a similar order of efficiencies: 260>160>568>ZPMOP>R68>640>TB6PMOP>CNS>12-AA>11-AA>TBHQ. Spearman correlation coefficient analyses indicated that the adherent rates of leukocytes to endothelial cells or smooth muscle cells treated with deAgrs had significantly negative correlation to their deaggregating abilities. Conclusion: DeAgrs effectively inhibit TNF-alpha-mediated leukocyte adhesion in vitro by breaking up hydrophobic lipophilic interactions, thus may be further tested for blocking atherogenesis.