BackgroundBradykinin (BK) induces angiogenesis by promoting vessel permeability, growth and remodeling. This study aimed to demonstrate that the B2R antagonist, fasitibant, inhibits the BK pro-angiogenic effects.MethodologyWe assesed the ability of fasibitant to antagonize the BK stimulation of cultured human cells (HUVEC) and circulating pro-angiogenic cells (PACs), in producing cell permeability (paracellular flux), migration and pseocapillary formation. The latter parameter was studied in vitro (matrigel assay) and in vivo in mice (matrigel plug) and in rat model of experimental osteoarthritis (OA). We also evaluated NF-κB activation in cultured cells by measuring its nuclear translocation and its downstream effectors such as the proangiogenic ciclooxygenase-2 (COX-2), prostaglandin E-2 and vascular endothelial growth factor (VEGF).Principal findingsHUVEC, exposed to BK (1–10 µM), showed increased permeability, disassembly of adherens and tight-junction, increased cell migration, and pseudocapillaries formation. We observed a significant increase of vessel density in the matrigel assay in mice and in rats OA model. Importantly, B2R stimulation elicited, both in HUVEC and PACs, NF-κB activation, leading to COX-2 overexpression, enhanced prostaglandin E-2 production. and VEGF output. The BK/NF-κB axis, and the ensuing amplification of inflammatory/angiogenic responses were fully prevented by fasitibant as well as by IKK VII, an NF-κB. Inhibitor.ConclusionThis work illustrates the role of the endothelium in the inflammation provoked by the BK/NF-κB axis. It also demonstates that B2R blockade by the antaogonist fasibitant, abolishes both the initial stimulus and its amplification, strongly attenuating the propagation of inflammation.

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BACKGROUND AND PURPOSEBradykinin, through its B2 receptor, is involved in inflammatory processes related to arthropathies. In carrageenan and lipopolysaccharide (LPS)-induced arthritis in rat, the anti-inflammatory activity of MEN16132, a potent and selective kinin B2 receptor antagonist, was compared with that of steroidal and nonsteroidal anti-inflammatory drugs. The interaction between MEN16132 and dexamethasone was also investigated. EXPERIMENTAL APPROACHDrugs, alone or in combination, were injected into the knee joint 30 min before intra-articular administration of carrageenan or LPS, in pentobarbital anaesthetized rats. Effects on incapacitation, oedema, neutrophil recruitment and kallikrein system activation, in the knee joint, were assessed. KEY RESULTSMEN16132 and dexamethasone (10-300 mg per knee) dose-dependently reduced carrageenan-induced joint pain, oedema and neutrophil infiltration, reaching a maximal inhibition of about 50%. Dexketoprofen exerted a similar analgesic activity, whereas it did not affect the other inflammatory responses. MEN16132 showed a partial inhibition of LPS-induced joint pain, whereas dexamethasone produced a full analgesic effect. Combination of MEN16132 and dexamethasone showed a strong synergistic interaction in inhibiting both carrageenan and LPS-induced knee joint inflammation. Dexamethasone did not prevent the contact activation of prekallikrein by carrageenan and the subsequent release of kallikreins and bradykinin in the synovium. CONCLUSIONS AND IMPLICATIONSSteroids and kinin B2 receptor antagonists appear to relieve arthritic symptoms induced by carrageenan or LPS and act synergistically to inhibit joint inflammation. This could have interesting therapeutic implications, possibly opening the way for combination therapies in the control of inflammatory arthropathies. AbbreviationsCI, combination index; COX, cyclooxygenase; IL, interleukin; LPS, lipopolysaccharide; MPO, myeloperoxidase; NSAID, non-steroidal anti-inflammatory drug; PBS, phosphate buffered saline; PBS-T, PBS 0.1% Tween 20; TNF, tumour necrosis factor BJP British Journal of Pharmacology

We have tested the activity of 4-(S)-amino-5-(4-[4-[2,4-dichloro-3-(2,4-dimethyl-8-quinolyloxymethyl)phenylsulfonamido]-tetrahydro-2H-4-pyranylcarbonyl] piperazino)-5-oxopentyl](trimethyl)ammonium chloride hydrochloride (MEN16132), a novel nonpeptide kinin B(2) receptor antagonist, on bradykinin (BK)-induced inflammatory responses, bronchoconstriction, and hypotension in guinea pigs. After i.v. (1-10 nmol/kg i.v.), intratracheal (i.t.) (10-100 nmol/kg i.t.), or aerosol (0.01-0.1 mM/5 min) administration, MEN16132 inhibited in a dose-dependent manner the bronchoconstriction induced by BK (10 nmol/kg i.v.). MEN16132 was more potent and possessed a longer duration of action as compared with the peptide B(2) receptor antagonist icatibant (HOE140; H-D-Arg-Arg-Pro-Hyp-Gly-Thi-Ser-D-Tic-Oic-Arg-OH trifluoroacetate). After i.v. administration, its inhibitory effect on bronchoconstriction lasted more than 8 h at 30 nmol/kg. When administered by i.v. or i.t. routes, the dose completely inhibiting bronchoconstriction also partially reduced the hypotensive response to BK, whereas after aerosol administration, the inhibitory effect was limited to respiratory level. Intranasal (i.n.) administration of MEN16132 (0.01-0.3 nmol/nostril) reduced, in a dose-dependent and long-lasting manner, the nasal mucosa plasma protein extravasation induced by BK (100 nmol/nostril), and it exerted a complete inhibition at about 30-fold lower dose than icatibant. At 1 nmol/nostril, MEN16132 activity was significant for at least 6 h with no systemic effect measured as inhibition of BK-induced hypotension, and at 10 nmol/nostril, the inhibitory effect lasted for more than 15 h with only a weak effect on hypotension. These findings indicate that in vivo MEN16132 is a potent kinin B(2) receptor antagonist with long duration of action, both after i.v. and local administration. A complete and prolonged inhibition of BK-induced bronchoconstriction or nasal inflammation can be achieved with MEN16132 topical administration (aerosol or i.n.) at doses devoid of systemic effects.