NCX 6560, a nitric oxide-releasing derivative of atorvastatin, inhibits cholesterol biosynthesis and shows anti-inflammatory and anti-thrombotic properties

Abstract

We compared the lipid-lowering, vasodilating, anti-thrombotic and anti-inflammatory properties of NCX 6560, a novel NO-releasing derivative of atorvastatin, with those of atorvastatin. NCX 6560 and atorvastatin induced similar inhibition of cholesterol biosynthesis in rat smooth muscle cells (IC 50 = 1.9 ± 0.4 and 3.9 ± 1.0 μM, respectively). However, in hyperlipidemic mice, a 5-week oral treatment with NCX 6560 (46.8 mg/kg/day, p.o.) was more effective than equivalent atorvastatin (40 mg/kg/day, p.o.) at lowering serum cholesterol (NCX 6560: − 21% vs controls, P < 0.05; atorvastatin: − 14% vs control, P = NS). In norepinephrine-precontracted rabbit aortic rings, NCX 6560-induced vasodilation (EC 50 = 53.5 ± 8.3 μM) and in PC12 cells it stimulated cGMP formation (EC 50 = 1.8 ± 0.7 μM), while atorvastatin was inactive. In lipopolysaccharide from Escherichia coli (LPS)-treated RAW 264.7 macrophages, NCX 6560 reduced iNOS expression and dimer assembly more efficiently than atorvastatin and inhibited nitrite accumulation (IC 50 = 6.7 ± 1.6 μM) and TNFα release. U46619- or collagen plus epinephrine-induced platelet pulmonary thromboembolism in mice was reduced by NCX 6560 at 46.8 mg/kg p.o. (mortality: − 44% and − 56% vs vehicle, respectively; P < 0.05), but not by atorvastatin 40 mg/kg, p.o. In the U46619-induced mortality model, isosorbide mononitrate (ISMN) (20 mg/kg, p.o.), a pure NO-donor, was also active (mortality: − 40%, P < 0.05). NCX 6560 significantly reduced ex vivo platelet adhesion to collagen at high shear (− 31 ± 1.3% vs vehicle), and so did ISMN (− 33.3 ± 1.7% vs vehicle). Atorvastatin was ineffective. NCX 6560, but not atorvastatin, reduced blood pressure in eNOS knockout mice (− 16%, P < 0.001 vs vehicle), an effect not observed in wild type mice. On the contrary, ISMN provoked a significant drop of blood pressure both in wild type (− 20%, P < 0.05 vs vehicle) and in eNOS−/− mice (− 21%, P < 0.05 vs vehicle). In conclusion, NCX 6560 exerts greater lipid-lowering, anti-thrombotic and anti-inflammatory effects than atorvastatin, due to a large extent to NO release.