ABSTRACT
Title
Nitric Oxide-donating statins decrease polymorphonuclear-mediated acute vascular inflammation in normocholesterolemic rabbits
Authors
R. Baetta1, A. Granata1, D. Miglietta2, D. Dellavecchia2, L. Arnaboldi1, P. Pfister3, A. Corsini1.
1Dept. of Pharmacological Sciences, University of Milan, Milan, Italy; 2Nicox Research Institute, Bresso, Milan, Italy; 3 NicOx SA, Sophia Antipolis, France
1Dept. of Pharmacological Sciences, University of Milan, Milan, Italy; 2Nicox Research Institute, Bresso, Milan, Italy; 3 NicOx SA, Sophia Antipolis, France
Abstract
Background - New evidence has emerged suggesting that polymorphonuclear leukocytes (PMN) can give important contributions to vascular inflammatory processes underlying the development of atherosclerosis, thus representing new possible targets for atheroprotection. HMG-CoA reductase inhibitors (statins) exert many pleiotropic effects in addition to the lowering of serum cholesterol levels, which are mediated, at least in part, by their ability to inhibit isoprenoid synthesis. Endothelium-derived nitric oxide (NO) is a major mediator of vasodilatory and anti-atherothrombotic actions in the vasculature. NO-donating statins are a new class of compounds designed with the aim of combining the pleiotropic effects of statins with the atheroprotective properties of NO (PNAS 2004;101:8497-8502).
Aim - To evaluate the effects of a short-term treatment with NO-donating derivatives of atorvastatin as compared to atorvastatin, on PMN infiltration in rabbit carotids subjected to perivascular collar placement, a model of acute arterial inflammation related to atherogenesis (Exp Cell Res 2002;274:197-206).
Methods and Results - NCX 6560, a nitroatorvastatin under early clinical development (Circulation 2010;122:A14267), and its structural analog NCX 616were used. In preliminary in vitro studies, the compounds were shown to retain the inhibitory activity of atorvastatin on HMG-CoA reductase (IC50= 7.7 and 8.7 nM, respectively, vs. 6.5 nM for atorvastatin) and to release bioactive NO (EC50 for vasorelaxing activity in isolated rabbit aortas = 53.5 and 10.4 mM, respectively).
In the in vivo study, chow-fed NZW rabbits (N=10/group) received a daily oral dose of vehicle or experimental compounds (equivalent to 5 mg/kg/day atorvastatin) for 6 days. One hour after the last dose of treatment, blood samples were collected from the central ear artery and collars were implanted around the right common carotid arteries. Twenty-four hours later carotids were removed, immunostained for PMN, and measured by image analysis.
Total plasma concentration of atorvastatin and its active metabolites (2-OH-atorvastatin and 4-OH-atorvastatin) measured by UPLC-MS/MS were similar in the 3 treatment groups (5.6, 4.2, and 4.5 nM for atorvastatin, NCX 6560, and NCX 616-treated rabbits, respectively). No changes in plasma cholesterol were detected, according to the short course of treatment. Conversely, treatment with both NO-donating statins was associated with a lower amount of PMN infiltration as compared to control (approx. -39% and -26% for NCX 616 and NCX 6560 respectively; p<0.05 vs control for NCX 616). Treatment with atorvastatin did not influence PMNinfiltration compared to control.
Conclusions - NO-donating derivatives of atorvastatin maintain the inhibitory activity of atorvastatin on HMG-CoA reductase while showing a further beneficial effect on vascular inflammation, which supports a pharmacological rationale for their clinical development.
Aim - To evaluate the effects of a short-term treatment with NO-donating derivatives of atorvastatin as compared to atorvastatin, on PMN infiltration in rabbit carotids subjected to perivascular collar placement, a model of acute arterial inflammation related to atherogenesis (Exp Cell Res 2002;274:197-206).
Methods and Results - NCX 6560, a nitroatorvastatin under early clinical development (Circulation 2010;122:A14267), and its structural analog NCX 616were used. In preliminary in vitro studies, the compounds were shown to retain the inhibitory activity of atorvastatin on HMG-CoA reductase (IC50= 7.7 and 8.7 nM, respectively, vs. 6.5 nM for atorvastatin) and to release bioactive NO (EC50 for vasorelaxing activity in isolated rabbit aortas = 53.5 and 10.4 mM, respectively).
In the in vivo study, chow-fed NZW rabbits (N=10/group) received a daily oral dose of vehicle or experimental compounds (equivalent to 5 mg/kg/day atorvastatin) for 6 days. One hour after the last dose of treatment, blood samples were collected from the central ear artery and collars were implanted around the right common carotid arteries. Twenty-four hours later carotids were removed, immunostained for PMN, and measured by image analysis.
Total plasma concentration of atorvastatin and its active metabolites (2-OH-atorvastatin and 4-OH-atorvastatin) measured by UPLC-MS/MS were similar in the 3 treatment groups (5.6, 4.2, and 4.5 nM for atorvastatin, NCX 6560, and NCX 616-treated rabbits, respectively). No changes in plasma cholesterol were detected, according to the short course of treatment. Conversely, treatment with both NO-donating statins was associated with a lower amount of PMN infiltration as compared to control (approx. -39% and -26% for NCX 616 and NCX 6560 respectively; p<0.05 vs control for NCX 616). Treatment with atorvastatin did not influence PMNinfiltration compared to control.
Conclusions - NO-donating derivatives of atorvastatin maintain the inhibitory activity of atorvastatin on HMG-CoA reductase while showing a further beneficial effect on vascular inflammation, which supports a pharmacological rationale for their clinical development.