Correlation of leukocyte adhesiveness, adhesion molecule expression and leukocyte-induced contraction following balloon angioplasty

1 The aim of this study was to examine the changes in leukocyte adhesion an d leukocyte-induced contraction in balloon-injured rabbit subclavian artery and to correlate these changes with vessel morphology and expression of ad hesion molecules on the injured arteries. 2 Rabbits were anaesthetized and their left subclavian arteries were injure d by balloon inflation and withdrawal followed by sacrifice at 2, 24, 48 h or 8 days after injury. The left and right subclavian arteries were removed and leukocytes were isolated from autologous rabbit blood. Leukocyte-induc ed contraction was measured in 5-HT precontracted artery rings and leukocyt e adhesion was measured using Cr-51-labelled leukocytes. Immunocytochemistr y using paraffin-embedded tissue was employed to detect changes in the expr ession of adhesion molecules on injured arteries. 3 Autologous leukocytes caused a contraction of rabbit subclavian artery ri ngs, which was prevented by L-NAME (10(-3) M). Balloon-induced injury aboli shed the contractile response to leukocytes, which correlated with loss of carbachol-induced relaxation 4 Balloon injury markedly enhanced the adhesiveness of the subclavian arter y for leukocytes, most notably at 24 and 48 h after injury (1.7 and 1.8 fol d respectively). Increased leukocyte adhesion at these two time points corr elated with an upregulation of E-selectin, P-selectin and VCAM-1 expression on the remaining endothelium of the injured artery. 5 Vessel morphology revealed that balloon inflation had induced an infiltra tion of inflammatory cells into the vessel wall, the greatest increase bein g seen at 24 h after injury. 6 It is concluded that an increase in the expression of E-selectin, P-selec tin and VCAM-1 following balloon-induced injury leads to enhanced leukocyte adhesion and migration into the injured vessel.