NCX4016 (NO-Aspirin) has multiple inhibitory effects in LPS-stimulated human monocytes

1 NCX4016 (2 acetoxy-benzoate 2-(2-nitroxymethyl)-phenyl ester, NicOx S.A., France) is an antithrombotic agent, chemically related to acetylsalicylic acid (ASA) and able to release NO. 2 We tested the effects of NCX4016 and ASA on the release of the thromboxan e (TX) A(2) metabolite TXB2, tumour necrosis factor-alpha (TNF-alpha), inte rleukin-6 (IL-6), expression and activity of tissue factor (TF) in stimulat ed, adherent human monocytes. 3 Both ASA and NCX4016 1-1000 mu mol(-1) dose-dependently reduced TXB2 conc entration, measured by RIA in the supernatant of 10 mug ml(-1) LPS-stimulat ed cells. NCX4016 activity was comparable to that of equimolar ASA when inc ubation lasted 6 h (NCX4016 30 mu mol l(-1): -86.0 +/- 10.1%, NCX4016 300 m u mol l(-1): -92.2 +/-9.0%, ASA 30 mu mol l(-1): -92.3 +/-7.5%, ASA 300 mu mol l(-1): -97.3 +/-1.0%, n=6, M +/-s.d.). Most of the activity of NCX4016 up to 100 pmol l(-1) was prevented by 10 Pmol l(-1) ODQ, inhibitor of cycli c GMP. 4 NCX4016 100-300 mu mol l(-1) reduced TNF-alpha (NCX4016 300 mu mol l(-1) = -77.2 +/- 19.9%, n=6) and IL-6 (NCX4016 300 mu mol l(-1): -61.9 +/- 15.2% , n=6) in LPS stimulated monocytes while ASA had no significant effects. 5 TF activity (NCX4016 300 mu mol l(-1): 53.7 +/- 39.9%, n=4) and immunorea ctive TF (NCX4016 300 mu mol l(-1): -93.9 +/-7.9%, n=7), measured in the su pernatant of stimulated cells, were also dose-dependently inhibited by NCX4 016 but not by ASA. 6 The present results indicate that NCX4016 inhibits TXA(2) generation as w ell as cytokine release and TF in human monocytes partly via NO-dependent m echanisms. NCX4016 may have a favourable profile of activities in the clini cal setting of athero-thrombosis.