Activity of the lipoxygenase inhibitor 1-phenyl-3-pyrazolidinone (phenidone) and derivatives on the expression of adhesion molecules on human umbilical vascular endothelial cells

Introduction

Leucocyte adhesion contributes to perfusion abnormalities and tissue damage, and during trauma, shock or overwhelming inflammation. This study was performed to determine whether the lipoxygenase inhibitor phenidone and derivatives decrease the expression of adhesion molecules on stimulated endothelial cells and attenuate leucocyte–endothelial interactions under flow in vitro.

Methods

TNF-α-stimulated human umbilical vascular endothelial cells (HUVEC) were incubated with phenidone, 4-methyl-phenidone, 4-4-dimethyl-phenidone, 5-methyl-phenidone, 5-phenyl-phenidone, and indometacin. We tested the inhibition of adhesion molecule expression (intracellular adhesion molecule-1 [ICAM-1], vascular cell adhesion molecule-1 [VCAM-1], E-selectin) on TNF-α-stimulated HUVEC after preincubation, coincubation and postincubation of the derivatives. The inhibition of endothelial cell expression was measured by flow cytometry and northern blot analysis. Adhesion of isolated leucocytes to pretreated endothelium was examined in a parallel plate flow chamber at a shear stress of 1.5 dynes/cm².

Results

All cyclooxygenase and lipoxygenase inhibitors downregulated E-selectin, ICAM-1 and VCAM-1 in a dose-dependent manner after preincubation. Coincubation and postincubation did not decrease adhesion molecule expression. 4-4-Dimethyl-phenidone, was the most effective compound (IC₅₀ 273 μM) compared with the other tested cyclooxygenase and lipoxygenase inhibitors. Lipoxygenase inhibitors decreased E-selectin expression in northern blot analysis, whereas E-selectin expression was increased after indometacin incubation. Similarly, leucocyte adhesion was attenuated under flow conditions. We conclude that lipoxygenase inhibitors are able to decrease systemic inflammatory endothelial cell response.

Conclusion

Lipoxygenase Inhibitors are of therapeutical interest for the treatment of overwhelming systemic inflammation during shock, trauma, and sepsis.