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RESEARCH PRODUCT

Sodium/hydrogen exchange inhibition with cariporide reduces leukocyte adhesion via P-selectin suppression during inflammation

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Background and purpose: The Na+/H+ exchange (NHE) inhibitor cariporide is known to ameliorate ischaemia/reperfusion (I/R) injury by reduction of cytosolic Ca2+ overload. Leukocyte activation and infiltration also mediates I/R injury but whether cariporide reduces I/R injury by affecting leukocyte activation is unknown. We studied the effect of cariporide on thrombin and I/R induced leukocyte activation and infiltration models and examined P-selectin expression as a potential mechanism for any identified effects. Experimental approach: An in vivo rat mesenteric microcirculation microscopy model was used with stimulation by thrombin (0.5 μ ml−1) superfusion or ischaemia (by haemorrhagic shock for 60 min) and reperfusion (90 min). Key results: Treatment with cariporide (10 mg kg−1 i.v.) significantly reduced leukocyte rolling, adhesion and extravasation after thrombin exposure. Similarly, cariporide reduced leukocyte rolling (54±6.2 to 2.4±1.0 cells min−1, P<0.01), adherence (6.3±1.9 to 1.2±0.4 cells 100 μm−1, P<0.01) and extravasation (9.1±2.1 to 2.4±1.1 cells per 20 × 100 μm perivascular space, P<0.05), following haemorrhagic shock induced systemic ischaemia and reperfusion. The cell adhesion molecule P-selectin showed a profound decrease in endothelial expression following cariporide administration in both thrombin and I/R stimulated groups (35.4±3.2 vs 14.2±4.1% P-selectin positive cells per tissue section, P<0.01). Conclusions and implications: The NHE inhibitor cariporide is known to limit reperfusion injury by controlling Ca2+ overload but these data are novel evidence for a vasculoprotective effect of NHE inhibition at all levels of leukocyte activation, an effect which is likely to be mediated at least in part by a reduction of P-selectin expression. British Journal of Pharmacology (2008) 153, 1678–1685; doi:10.1038/sj.bjp.0707647; published online 10 March 2008