Abstract
Background We previously demonstrated that low concentrations of a new antihistamine levocetirizine inhibited eosinophil transmigration through human microvascular endothelial cells.
Objective Here, the inhibitory effect of levocetirizine on eosinophil adhesion to recombinant human vascular cell adhesion molecule-1 (rhVCAM)-1 was examined under conditions of shear stress using an in vitro model of the post-capillary venules.
Methods Eosinophils isolated from normal subjects were pre-incubated with a concentration range of levocetirizine (10(-6)-10(-10) M) or negative dilution control. Resting or granulocyte macrophage-colony stimulating factor (GM-CSF)-stimulated cells were pumped through rhVCAM-1 (10 mu g/mL) coated capillary tubes using a microfluidic syringe pump at a precise and constant flow rate (1 dyn/cm(2)). Images of rolling and firmly adherent eosinophils were captured using real-time video microscopy.
Results Levocetirizine significantly inhibited resting eosinophil adhesion to rhVCAM-1 with maximal effect at 10(-8) M with an EC50 of 10(-9) M. Levocetirizine almost abolished resting eosinophil adhesion by the 15 min time-point. GM-CSF significantly enhanced eosinophil adhesion and their ability to flatten on rhVCAM-1. Both phenomena were inhibited by levocetirizine in a dose-dependent manner, at both 5 and 15 min (optimal concentration of 10(-8) M with an EC50 of 10(-9) M) Real-time imaging revealed that the effect of levocetirizine on post-adhesion behaviour (detachment, flatness) contributed to its inhibitory action on eosinophil adhesion to rhVCAM-1. In contrast, very late antigen (VLA)-4 mAb inhibited eosinophil adhesion to rhVCAM-1 from the earliest time-points.
Conclusion Physiologically relevant concentrations of levocetirizine inhibit resting and GM-CSF-stimulated firm eosinophil adhesion to rhVCAM-1 under flow conditions.
Original language | English |
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Pages (from-to) | 1073-1079 |
Number of pages | 7 |
Journal | Clinical & experimental allergy |
Volume | 35 |
Issue number | 8 |
DOIs | |
Publication status | Published - Aug 2005 |
Keywords
- adhesion
- antihistamines
- eosinophils
- flow conditions
- levocetirizine
- VCAM-1
- VLA-4
- endothelial-cells
- transendothelial migration
- leukocyte transmigration
- integrin affinity
- L-selectin
- cetirizine
- histamine
- eotaxin
- neutrophil
- induction