Bronchodilatory and anti-inflammatory effects of ASM-024, a nicotinic receptor ligand, developed for the treatment of asthma.

Conventional asthma and COPD treatments include the use of bronchodilators, mainly β2-adrenergic agonists, muscarinic receptor antagonists and corticosteroids or leukotriene antagonists as anti-inflammatory agents. These active drugs are administered either separately or given as a fixed-dose combination medication into a single inhaler. ASM-024, a homopiperazinium compound, derived from the structural modification of diphenylmethylpiperazinium (DMPP), has been developed to offer an alternative mechanism of action that could provide symptomatic control through combined anti-inflammatory and bronchodilator properties in a single entity. A dose-dependent inhibition of cellular inflammation in bronchoalveolar lavage fluid was observed in ovalbumin-sensitized mice, subsequently treated for 3 days by nose-only exposure with aerosolized ASM-024 at doses up to 3.8 mg/kg (ED50 = 0.03 mg/kg). The methacholine ED250 values indicated that airway hyperresponsivenness (AHR) to methacholine decreased following ASM-024 administration by inhalation at a dose of 1.5 mg/kg, with a value of 0.145 ± 0.032 mg/kg for ASM 024-treated group as compared to 0.088 ± 0.023 mg/kg for untreated mice. In in vitro isometric studies, ASM-024 elicited dose-dependent relaxation of isolated mouse tracheal, human, and dog bronchial preparations contracted with methacholine and guinea pig tracheas contracted with histamine. ASM-024 showed also a dose and time dependant protective effect on methacholine-induced contraction. Overall, with its combined anti-inflammatory, bronchodilating and bronchoprotective properties, ASM-024 may represent a new class of drugs with a novel pharmacological approach that could prove useful for the chronic maintenance treatment of asthma and, possibly, COPD

ASM-024, a piperazinium compound, promotes the in vitro relaxation of β2-adrenoreceptor desensitized tracheas.

Inhaled β2-adrenoreceptor agonists are widely used in asthma and chronic obstructive pulmonary disease (COPD) for bronchoconstriction relief. β2-Adrenoreceptor agonists relax airway smooth muscle cells via cyclic adenosine monophosphate (cAMP) mediated pathways. However, prolonged stimulation induces functional desensitization of the β2-adrenoreceptors (β2-AR), potentially leading to reduced clinical efficacy with chronic or prolonged administration. ASM-024, a small synthetic molecule in clinical stage development, has shown activity at the level of nicotinic receptors and possibly at the muscarinic level and presents anti-inflammatory and bronchodilator properties. Aerosolized ASM-024 reduces airway resistance in mice and promotes in-vitro relaxation of tracheal and bronchial preparations from animal and human tissues. ASM-024 increased in vitro relaxation response to maximally effective concentration of short-acting beta-2 agonists in dog and human bronchi. Although the precise mechanisms by which ASM-024 promotes airway smooth muscle (ASM) relaxation remain unclear, we hypothesized that ASM-024 will attenuate and/or abrogate agonist-induced contraction and remain effective despite β2-AR tachyphylaxis. β2-AR tachyphylaxis was induced with salbutamol, salmeterol and formoterol on guinea pig tracheas. The addition of ASM-024 relaxed concentration-dependently intact or β2-AR desensitized tracheal rings precontracted with methacholine. ASM-024 did not induce any elevation of intracellular cAMP in isolated smooth muscle cells; moreover, blockade of the cAMP pathway with an adenylate cyclase inhibitor had no significant effect on ASM-024-induced guinea pig trachea relaxation. Collectively, these findings show that ASM-024 elicits relaxation of β2-AR desensitized tracheal preparations and suggest that ASM-024 mediates smooth muscle relaxation through a different target and signaling pathway than β2-adrenergic receptor agonists. These findings suggest ASM-024 could potentially provide clinical benefit when used adjunctively with inhaled β2-adrenoreceptor agonists in those patients exhibiting a reduced response to their chronic use

Proinflammatory effect of Pediococcus pentosaceus, a bacterium used as hay preservative

Bacterial cultures, such as Pediococcus pentosaceus, are used to treat hay with the objective of preventing hay heating and moulding, and thus, the development of the microbial growth which causes farmer’s lung. The aim of this study was to investigate whether such bacterial cultures have the potential to induce a pulmonary inflammatory response. Mice were instilled 3 days·week-1 for 3 weeks with either saline or nonviable preparations of P. pentosaceus, Saccharopolyspora rectivirgula, Lactococcus lactis (control bacteria) or with the combinations of S. rectivirgula and P. pentosaceus. P. pentosaceus induced a significant inflammatory response in the lung which was similar to that produced by S. rectivirgula. L. lactis produced a response of a lower intensity. The total number of cells in bronchoalveolar lavage were: S. rectivirgula: 6.4×105 cells·mL-1; P. pentosaceus: 4.3×105 cells·mL-1; S. rectivirgula + P. pentosaceus: 5.4×105 cells·mL-1, L. lactis: 6.8×105 cells·mL-1 and saline group 3.7×104 cells·mL-1. The lung index was higher in S. rectivirgula + P. pentosaceus and P. pentosaceus groups than in S. rectivirgula, L. lactis and saline groups. The quantity of specific immunoglobulin G and A (IgG and IgA) to P. pentosaceus and L. lactis levels (in the blood and/or lavage fluid) were similar to those against S. rectivirgula. In mice, P. pentosaceus has the potential to induce a similar inflammatory response in the lung as S. rectivirgula, which is the most common antigen responsible for farmer’s lung disease in Quebec. Further studies are needed to verify whether farmers can develop farmer’s lung or other lung responses to this new potential antigen

Hypersensitivity pneumonitis in peat moss processing plant workers

A nonsmoking 54-yr-old man, employed in a peat moss packaging plant, developed dyspnea and recurrent fever. The diagnosis of hypersensitivity pneumonitis (HP) was made. Thirteen of 14 coworkers and 13 nonexposed control subjects were studied. Five workers were nonsmokers, two were minimal smokers, and six were smokers. HP was found in another subject. Monocillium sp. and Penicillium citreonigrum, 4.6 × 107 CFU/g, were found in the peat moss. Three nonsmokers, the two minimal smokers (including the subject with HP), and the index case had antibodies to these microorganisms; none of the six heavy smokers had antibodies. Serum TNF- a was higher in the workers than in the control subjects (0.930 ± 0.177 versus 0.350 ± 0.076). Three of the four asymptomatic seropositive workers and two seronegative smokers were further evaluated. All three seropositive workers had normal lung functions and CT but they all had a lymphocytic alveolitis (30, 34, and 68% lymphocytes in their bronchoalveolar lavage [BAL]). The smokers had normal lung functions, CT, and percentage of BAL lymphocytes (3 and 13%). This study identified a previously unrecognized work environment that can lead to HP and documented a protective effect of smoking on the response to antigens

Farming practices and the respiratory health risks of swine confinement buildings

This study investigated whether clean swine confinement buildings (SCB) are less harmful to the respiratory system than older and dirtier facilities. Eight healthy volunteers were exposed for 4 h, at 1 week intervals, to eight SCB representing the widest possible range of cleanliness. Each volunteer and a technician rated the SCB for cleanliness from 1±10, 1 being the cleanest possible. Airborne dust, bacteria, endotoxin levels, molds, and ammonia were measured. For each volunteer measured, before and after each exposure, forced expiratory flows (forced expiratory volume in one second (FEV1), and forced vital capacity), white cells in nasal wash and venous blood, and nasal lavage levels of interleukin (IL)-8 and serum levels of IL-6. A methacholine challenge was obtained at baseline and following each exposure. Cleanliness scores ranged 1.5±8.25. Mean airborne levels were: dust 3.54 mg.m-3 bacteria 4.256105 CFU.m-3; endotoxins 404 EU.m-3; molds 883 CFU.m-3; ammonia 20.7 parts per million (ppm). Expiratory flows decreased after exposure (FEV1 from 4.8 0.7 to 4.4 0.7, p<0.001), neutrophils in the nasal wash and white blood cells increased (28.5 37 to 424 2076103 , 5.4 1.0 to 7.4 1.76109 cells.mL-1 respectively), IL-8 increased from 158 311 to 2679 639 pg.mL-1, IL-6 from 0.15 0.26 to 2.34 0.92 pg.mL-1, (p<0.001). All SCB were similarly harmful. In conclusion, modern farming has not succeeded in making swine confinement buildings inoffensive to exposed subjects

Additive effects of ASM-024 on beta2-agonists airway smooth muscle relaxation in dog bronchi.

<p>A) Dog bronchial preparations were contracted with 10–5 M methacholine and cumulative concentrations of ASM-024 or salbutamol added. ASM-024-induced bronchial relaxation required higher concentrations than the β2-AR agonist salbutamol (EC50 = 45.21 ± 13.74 μM for ASM-024 vs EC50 = 1.75 ± 1.83 μM for salbutamol). Salbutamol decreased the tension of precontracted dog bronchi by a maximum of 53%; the addition of 10–3 M ASM-024 further relaxed bronchial rings to below the applied basal tension. B) Representative tension recording depicting relaxation of dog bronchi following cumulative concentrations of salbutamol and ASM-024. n = 4–6 bronchial preparations from 3 different dogs. C) Representative tension recording showing that salbutamol, at 10–6 M maximally decreased the tension of contracted human bronchi; the addition of 10–4 M and 10–3 M ASM-024 to the maximal effective concentration of salbutamol increased relaxation to below the applied basal tension.</p

Effect of ASM-024 on cellular inflammation.

<p>ASM-024 was administered by (A) nebulization of a solution and (B) orally to OVA-sensitized mice. A dose-related inhibition of inflammation is observed, no further inhibitory effect observed at a dose higher than 10 mg/kg p.o.; Values are mean ± SD. * Significantly different from vehicle control groups; p≤0.001; n = 8–9; ED₅₀ p.o. = 3.55 mg/kg; ED₅₀ inhalation = 0.03 mg/kg.</p

Relaxant Effects of ASM-024, on Salbutamol Desensitized Guinea-Pig Tracheas.

<p>A) Intact guinea pig tracheas were studied before or after 4 h of exposure to the β2 agonist salbutamol. A reduced relaxation response to the β2 agonist was observed after 4 hour exposure to salbutamol (p <0.05). B) No significant difference was observed on the relaxation response curves of ASM-024 on intact or salbutamol desensitized tracheas. EC50 = 40 ± 9 μM for intact tracheas; EC₅₀ = 25 ± 11 μM for desensitized tracheas; values are means ± SD, n = 4.</p

Effective dose of methacholine (mg/kg) required to induce a 250% increase of airway resistance.

a<p>Inhalation, ^b Intranasal</p>*<p>p<0.05 compared to vehicle-treated OVA-sensitized mice.</p><p>ASM-024 administered by intranasal or inhalation routes immediately prior to the methacholine challenge to OVA-sensitized mice attenuated airway hyper-responsiveness.</p