Reparixin, a specific interleukin-8 inhibitor, has no effects on inflammation during endotoxemia.

Reparixin antagonizes interleukin-8 (IL-8) on the level of signal transduction in vitro. We hypothesized that IL-8 mediates some of the reactions occurring during acute inflammation and specifically that IL-8 may be a mediator of endotoxin induced neutrophilia. We therefore tested the effects of reparixin on humoral and cellular parameters in LPS-induced acute systemic inflammation. The study is a randomized (3:2 active:placebo), double-blind, placebo-controlled parallel group trial. Twenty healthy male volunteers randomly received either reparixin (12) or placebo (8) intravenously. One hour after the start of reparixin/placebo infusion a bolus of 2 ng/kg endotoxin was infused over 1-2 min. Blood samples were obtained over 24 h. Reparixin, being metabolized to ibuprofen, suppressed serum thromboxane B2 levels by 78 percent compared to baseline and control at 8 h. LPS-induced neutrophilia was not significantly affected by reparixin in human volunteers. Consistently, reparixin did not alter the lymphocyte or monocyte counts and had no effect on LPS-induced systemic inflammation as measured by tumor necrosis factor alpha (TNF-alpha) or interleukin-6 (IL-6) release. Regulation of IL-8 receptors CXCR1 and 2 and the degranulation marker CD11b showed the expected kinetics. Reparixin had no effect on thrombin formation as measured by prothrombin fragment (F1+2). In conclusion, our study showed that reparixin was safe but had no impact on endotoxin induced inflammation. In contrast to previous studies with its metabolite ibuprofen, reparixin does not enhance inflammation in this model.

S-CMC-Lys-dependent stimulation of electrogenic glutathione secretion by human respiratory epithelium.

Glutathione (GSH) is one of the most important defense mechanisms against oxidative stress in the respiratory epithelial lining fluid. Considering that GSH secretion in respiratory cells has been postulated to be at least partially electrogenic, and that the mucoregulator S-carbocysteine lysine salt monohydrate (S-CMC-Lys) can cause an activation of epithelial Cl(-) conductance, the purpose of this study was to verify whether S-CMC-Lys is able to stimulate GSH secretion. Experiments have been performed by patch-clamp technique, by high-performance liquid chromatography (HPLC) assay, and by Western blot analysis on cultured lines of human respiratory cells (WI-26VA4 and CFT1-C2). In whole-cell configuration, after cell exposure to 100 microM S-CMC-Lys, a current due to an outward GSH flux was observed, which was inhibitable by 5-nitro-2-(3-phenylpropylamino)-benzoate and glibenclamide. This current was not observed in CFT1-C2 cells, where a functional cystic fibrosis transmembrane conductance regulator (CFTR) is lacking. Inside-out patch-clamp experiments (GSH on the cytoplasm side, Cl(-) on the extracellular side) showed the activity of a channel, which was able to conduct current in both directions: the single channel conductance was 2-4 pS, and the open probability (P(o)) was low and voltage-independent. After preincubation with 100 microM S-CMC-Lys, there was an increase in P(o), in the number of active channels present in each patch, and in the relative permeability to GSH vs Cl(-). Outwardly directed efflux of GSH could also be increased by protein kinase A, adenosine 5'-triphosphate, and cyclic adenosine monophosphate (cAMP) added to the cytoplasmic side (whole-cell configuration). The increased secretion of GSH observed in the presence of S-CMC-Lys or 8-bromoadenosine-3',5'-cyclic monophosphate was also confirmed by HPLC assay of GSH on a confluent monolayer of respiratory cells. Western blot analysis confirmed the presence of CFTR in WI-26VA4 cells. This study suggests that S-CMC-Lys is able to stimulate a channel-mediated GSH secretion by human respiratory cells: electrophysiological and pharmacological characteristics of this channel are similar to those of the CFTR channel.

Antioxidant activity of carbocysteine lysine salt monohydrate.

BACKGROUND: Reactive oxygen radicals are involved in many respiratory diseases, including chronic obstructive pulmonary disease (COPD). Carbocysteine lysine salt monohydrate (CLS) is a mucoactive drug effective in the treatment of bronchopulmonary diseases characterized by mucus alterations, including COPD. In the present study, the antioxidant activity of CLS was studied in vitro in three different oxygen radical producing systems, i.e. bronchoalveolar lavages (BAL) from patients affected by COPD, ultrasound treated human serum and cultured human lung endothelial cells challenged with elastase. METHODS: BAL, exposed or not to different concentrations of CLS (1.5-30 mM), was assayed for free radical content by fluorometric analysis of DNA unwinding (FADU) or by cytochrome c reduction kinetics. Human serum was treated with ultrasound in the presence or absence of CLS (1.5, 2.5 mM) or N-acetyl cysteine (NAC; 4, 5 mM) and assayed for free radical content by FADU. Human endothelial cells cultured in vitro from pulmonary artery were incubated with elastase (0.3 IU/mL), in the presence or absence of glutathione (GSH; 0.65 mM) or CLS (0.16 mM). The supernatant was tested for cytochrome c reduction kinetics whereas cell homogenates were assessed for xanthine oxidase (XO) content by SDS-PAGE. RESULTS: Results showed that CLS is more effective as an in vitro scavenger in comparison to GSH and NAC. CLS reduced the damage of DNA from healthy donors exposed to COPD-BAL and was able to quench clastogenic activity induced in human serum by exposure to ultrasound at concentrations as low as 2.5 mM. NAC protect DNA from radical damage, starting from 5 mM. In human lung endothelial cells cultured in presence of elastase, CLS (0.16 mM) decreased xanthine oxidase activity. CONCLUSIONS: These results suggest that CLS could act by interfering with the conversion of xanthine dehydrogenase into superoxide-producing xanthine oxidase. The antioxidant activity of CLS could contribute to its therapeutic activity by reducing radical damage to different lung structures.

Comparative bioavailability and tolerability study of two intramuscular formulations of thiocolchicoside in healthy volunteers.

The comparative bioavailability and tolerability of two intramuscular fomulations of thiocolchicoside (test, Thiocolchicoside, 4 mg ampoules, Dompé S.p.A.; reference, Muscoril, 4 mg ampoules, Inverni della Beffa S.p.A.) were investigated in twelve healthy volunteers according to a single dose (4 mg), cross-over, randomized design. Plasma thiocolchicoside concentrations were determined by using a validated specific HPLC/MS assay and local tolerability was investigated by assessing subjective pain intensity on a visual analogue scale (VAS), reddening at the injection site, and plasma creatinine phosphokinase (CPK) levels. Pharmacokinetic parameters after administration of the test formulation were similar to those observed after administration of the reference (Tmax 0.50 (0.25-1.00) vs 0.50 (0.25-1.00), median and range; Cmax 115.5 +/- 26.6 vs 113.2 +/- 40.4 ng/ml; AUC 291.6 +/- 77.7 vs 283.3 +/- 98.9 ng.h/ml, means +/- SD). Relative bioavailability (F) was 1.05 +/- 0.13. Statistical comparison of pain intensity, CPK levels and occurrence of redness at the injection site did not show statistically significant differences between formulations. It is concluded that the investigated test formulation is bioequivalent and equally well tolerated as the marketed reference formulation.

Species differences in the pharmacokinetics and metabolism of reparixin in rat and dog.

The pharmacokinetics and metabolism of reparixin (formerly repertaxin), a potent and specific inhibitor of the chemokine CXCL8, were investigated in rats and dogs after intravenous administration of [14C]-reparixin L-lysine salt. Protein binding of reparixin was investigated in vitro in rat, dog, rabbit, cynomolgus monkey and human plasma. Plasma protein binding of reparixin was >99% in the laboratory animals and humans up to 50 microg ml-1, but lower at higher concentrations. Although radioactivity was rapidly distributed into rat tissues, Vss was low (about 0.15 l kg-1) in both rat and dog. Nevertheless, reparixin was more rapidly eliminated in rats (t1/2 approximately 0.5 h) than in dogs (t1/2 approximately 10 h). Systemic exposure in dog was due primarily to parent drug, but metabolites played a more prominent role in rat. Oxidation of the isobutyl side-chain was the major metabolic pathway in rat, whereas hydrolysis of the amide bond predominated in dog. Urinary excretion, which accounted for 80-82% of the radioactive dose, was the major route of elimination in both species, and biotransformation of reparixin was complete before excretion.

Protective effect of ketoprofen lysine salt on interleukin-1beta and bradykinin induced inflammatory changes in hamster cheek pouch microcirculation.

OBJECTIVE: The purpose of this study was to assess the efficacy of topically applied ketoprofen lysine salt (KLS), a cyclooxygenase inhibitor, against the inflammatory changes induced by interleukin-1beta (IL-1beta) and bradykinin (BK) in hamster cheek pouch microcirculation. In addition, we characterised the pharmacological regulation of IL-1beta activity in this model. MATERIALS AND METHODS: Male Syrian hamsters were used. Microcirculation was visualised by fluorescent microscopy. Leukocyte adhesion, permeability, perfused capillary length (PCL) and capillary red blood cell (RBC) velocity were evaluated. TREATMENTS: KLS (25 microg/ml/min to 1.6 mg/ml/min) was topically applied for 3 min before topically administered IL-1beta (1microg/ml) and BK (10(-4) M). Monoclonal anti-mouse IL-1beta receptor antagonist (200 ng/ml), BK-B2 receptor antagonist (10(-6) M), PAF inhibitor (10(-5) M) and cycloheximide (10 microg/ml) were added topically 15, 10, 15 and 60 min, respectively, before IL-1beta (1 microg/ml). RESULTS: IL-1beta caused a significant increase in microvascular permeability, a decrease in capillary RBC velocity followed by increased leukocyte adhesion in postcapillary venules. BK caused a marked increase in leukocyte adhesion and no decrease in PCL and RBC velocity. Treatment with KLS significantly inhibited both the leukocyte adhesion and microvascular leakage induced by the two mediators. The inflammatory effects induced by IL-1beta were reduced by blockade of IL-1beta receptors and by a BK-B2 receptor antagonist but were not affected by a PAF antagonist and protein synthesis inhibition. CONCLUSIONS: These results demonstrate that KLS is effective in preventing early inflammatory changes induced by both IL-1beta and BK in the capillary network. Prostaglandin release and BK are essential components for IL-beta mediated responses, whereas neither PAF nor new protein synthesis appear to be linked to the early inflammatory changes induced by IL-1beta.

Levodropropizine does not affect P0.1 and breathing pattern in healthy volunteers and patients with chronic respiratory impairment.

To evaluate whether the peripherally acting antitussive levodropropizine could affect the respiratory drive and the breathing pattern, we performed a double-blind, randomised, cross-over trial in 12 healthy volunteers and 12 patients with chronic respiratory impairment associated with chronic obstructive pulmonary disease. Levodropropizine 6% drops (at the recommended dose for adults) or placebo were administered orally t.i.d. for 10 consecutive administrations. Mouth occlusion pressure (P0.1), minute ventilation (V(e)), tidal volume (V(t)), respiratory rate (RR), mean inspiratory flow (V(t)/T(i)), end-tidal CO(2) (EtCO(2)), oxygen saturation (SaO(2)), forced expiratory volume in 1 s (FEV(1)), and the response to a hypercapnic stimulus were measured before and 1 h after the first and the last drug administration. Levodropropizine did not modify P0.1 in basal conditions and after a hypercapnic stimulus, either in healthy volunteers or in patients. In parallel, levodropropizine did not significantly affect V(t), RR, V(e), V(t)/T(i) and EtCO(2) in both the populations. Minor changes were induced by levodropropizine on SaO(2) in healthy volunteers, which despite a statistical difference, were too low to gain a clinical significance. These results confirmed the respiratory safety of levodropropizine 6% drops administered at the recommended dosage either in healthy volunteers or patients with chronic respiratory impairment.