Dexamethasone does not modulate eosinophil adhesion to endothelial cells.
BACKGROUND
Glucocorticoids are representative agents in the anti-inflammatory treatment of allergic airway diseases. Although they reduce the number of tissue eosinophils, its exact mechanism has not been completely established.


OBJECTIVE
The present study was undertaken to evaluate whether dexamethasone modulates the adhesive property of eosinophils. The effect on the expression of endothelial adhesion molecules was also evaluated.


METHODS
Blood eosinophils from healthy subjects were incubated in the presence or absence of 0.1-1 microM of dexamethasone for 6 h at 37 degrees C. Eosinophil chemotaxis and adhesion to paraformaldehyde-fixed human pulmonary vascular endothelial cells (HPMEC) were then examined. The effects of dexamethasone on the expression of VCAM-1 and ICAM-1 on HPMEC were examined by cell ELISA.


RESULTS
1 microM dexamethasone significantly inhibited the chemotactic response of eosinophils to 1 microM formyl-methionyl-leucyl-phenylalanine (FMLP). On the other hand, dexamethasone did not modify either the spontaneous or FMLP-stimulated adhesion of eosinophils to resting HPMEC. Similarly, dexamethasone did not alter either the spontaneous adhesion of eosinophils to or the expression of VCAM-1 or ICAM-1 on HPMEC stimulated with IL-4 + TNF-alpha.


CONCLUSIONS
Dexamethasone does not modify the adhesive property of eosinophils or the expression of adhesion molecules on endothelial cells. Thus, it is unlikely that glucocorticoids directly modulate the adhesive interaction between eosinophils and endothelial cells.
Sutani
A
A
Pulmonary Division, Second Department of Internal Medicine, Saitama Medical School, Iruma-gun, Saitama, Japan.
Nagata
M
M
Yamamoto
H
H
Sakurai
M
M
Sakamoto
Y
Y
D000328:Adult; D000893:Anti-Inflammatory Agents / Q000494:pharmacology*; D002448:Cell Adhesion / Q000187:drug effects*; D002478:Cells, Cultured; D002634:Chemotaxis, Leukocyte / Q000187:drug effects; D003907:Dexamethasone / Q000494:pharmacology*; D004730:Endothelium, Vascular / Q000502:physiology*; D004804:Eosinophils / Q000276:immunology*; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000378:metabolism; D019010:Vascular Cell Adhesion Molecule-1 / Q000378:metabolism
D000893:Anti-Inflammatory Agents; D019010:Vascular Cell Adhesion Molecule-1; D018799:Intercellular Adhesion Molecule-1; D003907:Dexamethasone