Purpose: Polymorphonuclear neutrophils, the first leukocytes to infiltrate the inflamed tissue, can make important contributions to vascular inflammatory processes driving the development of atherosclerosis. We herein investigated the effects of atorvastatin and NCX 6560 (a nitric oxide (NO)-donating atorvastatin derivative that has completed a successful phase 1b study) on neutrophilic inflammation in carotid arteries of normocholesterolemic rabbits subjected to perivascular collar placement.
Methods: Atorvastatin or NCX 6560 were administered orally (5 mg/kg/day or equimolar dose) to New Zealand White rabbits for 6 days, followed by collar implantation 1 h after the last dose. Twenty-four hours later carotids were harvested for neutrophil quantification by immunostaining.
Results: Treatment with NCX 6560 was associated with a lower neutrophil infiltration (-39.5 %), while atorvastatin did not affect neutrophil content. The result was independent of effects on plasma cholesterol or differences in atorvastatin bioavailability, which suggests an important role of NO-related mechanisms in mediating this effect. Consistent with these in vivo findings, in vitro studies showed that NCX 6560, as compared to atorvastatin, had greater inhibitory activity on processes involved in neutrophil recruitment, such as migration in response to IL-8 and IL-8 release by endothelial cells and by neutrophils themselves. Pretreatment with NCX 6560, but not with atorvastatin, reduced the ability of neutrophil supernatants to promote monocyte chemotaxis, a well-known pro-inflammatory activity of neutrophils.
Conclusion: Experimental data suggest a potential role of NO-releasing statins in the control of the vascular inflammatory process mediated by polymorphonuclear neutrophils.