- [1-(4-fluorobenzyl)-5-hydroxy-indole-3-yl]-glyoxylic acid amide (AWD 12-281) is a highly potent and selective phosphodiesterase 4 (PDE4) inhibitor that was designed to have a metabolic profile that was optimized for topical administration. The aim of the current study was to explore the pharmacological profile of intratracheally administered AWD 12-281 in different models of asthma and chronic obstructive pulmonary disease (COPD) in comparison with steroids. To assess the anti-inflammatory potential of AWD 12-281, the antigen-induced cell infiltration in bronchoalveolar lavage fluid (BALF) of Brown Norway rats was determined. AWD 12-281 (ID 50 of 7 g/kg i.t.) as well as beclomethasone (0.1 g/kg i.t.) suppresses late-phase eosinophilia when administered intrapulmonary. Furthermore, AWD 12-281 has also strong anti-inflammatory properties when tested in lipopolysaccharide-induced acute lung neutrophilia in Lewis rats (ID 50 of 0.02 g/kg i.t.), ferrets (ID 50 of 10 g/kg i.t.), and domestic pigs (2-4 mg/pig i.t. or 1 mg/kg i.v.). In pigs, AWD 12-281 was as effective as beclomethasone (0.4 mg/pig i.t.) and dexamethasone (0.28 mg/kg i.v.), although at 3 to 10 times the dosage. The bronchodilatory activity of AWD 12-281 was assessed in sensitized guinea pigs. AWD 12-281 (1.5 mg/kg i.t., 1-h pretreatment) inhibited allergen-induced bronchoconstriction by 68% (parameter airway resistance). In sensitized BP-2 mice AWD 12-281 abolished the allergen-induced bronchial hyperresponsiveness and eosinophilia in BALF, showing dose dependence. When given orally, i.v. or i.t., AWD 12-281 has a considerably lower emetic potential than cilomilast in ferrets and roflumilast in pigs. When given topically by inhalation, no emesis could be induced in dogs up to the highest feasible dose (15 mg/kg in 50% lactose blend). These results indicate that AWD 12-281 is a unique potential new drug for the topical treatment of asthma and COPD.
1 IL-13 is an important mediator in in¯ammatory diseases such as asthma. IL-13 is mainly produced by T cells. However, signalling pathways leading to induction of this cytokine are not wellcharacterized. We analysed the regulation of IL-13 in human peripheral blood mononuclear cells and CD4 + T cells. 2 Cyclosporine (CsA) and FK-506 inhibited IL-13 synthesis, when cells were stimulated by TPA/ ionomycin. However, stimulation by a-CD3/a-CD28 led to an enhanced IL-13 synthesis. 3 NF-kB inhibitor N-tosyl-L-lysine chloromethylketone (TLCK) inhibited IL-13 synthesis more eectively after TPA/ionomycin stimulation. After a-CD3/a-CD28 stimulation, only 300 mM TLCK inhibited IL-13 synthesis. Dexamethasone inhibited IL-13 equally eective after a-CD3/a-CD28 and TPA/ionomycin stimulation. 4 p38 MAPK inhibitor SB203580 inhibited IL-13 synthesis only partially. MEK inhibitor U0126 inhibited TPA/ionomycin induced IL-13 synthesis very eectively, whereas a-CD3/a-CD28 stimulated IL-13 induction was resistant to this drug. 5 These results were con®rmed in puri®ed CD4 + T cells. In dierence to PBMCs a-CD3/a-CD28 stimulated IL-13 synthesis was eectively inhibited by CsA, FK-506 and U0126. 6 Therefore U0126 was tested in an animal model of allergic asthma. We could demonstrate for the ®rst time that inhibition of the MEK ± ERK cascade is a therapeutic option for asthma. Intraperitoneal administration of 10 mg kg 71 U0126 reduced lung eosinophilia in ovalbuminchallenged Brown Norway rats by 44%. 7 These results demonstrate that dierent signalling pathways are involved in regulating IL-13 synthesis in primary human T cells. Characterizing highly potent inhibitors of IL-13 synthesis can be exploited to identify new drugs to treat immunological diseases such as asthma.
SP-D accumulation is increased in this model of allergen-induced eosinophilia, both in upper and lower airways. The increase is unaffected by dexamethasone.
By virtue of its binding to cyclophilin, the cellular receptor for cyclosporine (CsA), we could identify a new compound D-43787 [N-[(1-tert-butyloxycarbonyl
The PDE4 inhibitors tested in our study are not suitable on their own for immunosuppressive therapy after lung transplantation because of the limited protection against the epithelial disturbance, infiltration of immune cells, and luminal obliteration. The strong anti-proliferative effect of the second-generation PDE4 inhibitors, cilomilast and roflumilast, suggest a benefit for the effective inhibition of immune cell and fibroblast proliferation contributing to the development of obliterative bronchiolitis.
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