Design, Synthesis, and Biological Characterization of Inhaled p38α/ß MAPK Inhibitors for the Treatment of Lung Inflammatory Diseases.

The identification of novel inhaled p38α/ß mitogen-activated protein kinases (MAPK) (MAPK14/11) inhibitors suitable for the treatment of pulmonary inflammatory conditions has been described. A rational drug design approach started from the identification of a novel tetrahydronaphthalene series, characterized by nanomolar inhibition of p38α with selectivity over p38γ and p38δ isoforms. SAR optimization of 1c is outlined, where improvements in potency against p38α and ligand-enzyme dissociation kinetics led to several compounds showing pronounced anti-inflammatory effects in vitro (inhibition of TNFα release). Targeting of the defined physicochemical properties allowed the identification of compounds 3h, 4e, and 4f, which showed, upon intratracheal instillation, low plasma levels, prolonged lung retention, and anti-inflammatory effects in a rat acute model of a bacterial endotoxin-induced pulmonary inflammation. Compound 4e, in particular, displayed remarkable efficacy and duration of action and was selected for progression in disease models of asthma and chronic obstructive pulmonary disease (COPD).

Preclinical profile of ciclesonide, a novel corticosteroid for the treatment of asthma.

Ciclesonide is a novel, inhaled corticosteroid under development for the treatment of asthma. Ciclesonide is activated to desisobutyryl-ciclesonide (des-CIC) in the lungs to provide potent anti-inflammatory activity. The investigations herein compared the activity of ciclesonide with fluticasone in animal models to assess efficacy/potency as an airway anti-inflammatory and the comparative side effect potential to consider the therapeutic ratio of each compound. In radioligand binding assays, des-CIC and fluticasone exhibited comparable high-affinity binding to the glucocorticoid receptor, whereas ciclesonide exhibited 100-fold less binding affinity. In the Brown Norway rat model of antigen-induced airway eosinophilia and in a model of Sephadex-induced lung edema, ciclesonide and fluticasone exhibited comparable efficacy. Interestingly, following 7-day intratracheal administration, ciclesonide elicited adrenal involution with a potency that was 44-fold less than fluticasone. Furthermore, ciclesonide was 22-fold less active than fluticasone in eliciting hypoplasia of the femoral growth plate. These data support the concept that ciclesonide acts as a parent compound that, when delivered to the airways, can be transformed into the active metabolite des-CIC, resulting in local high anti-inflammatory activity. Furthermore, ciclesonide possesses equivalent anti-inflammatory efficacy through pulmonary activation with a significantly improved safety profile in preclinical animal models compared with fluticasone.

Cellular pathology changes in rat skin following intradermal injection of nerve growth factor: neutrophil-dependent and -independent events.

Nerve growth factor (NGF) regulates the survival and development of specific populations of neurones and is involved in wound healing. A further area of study relating to the role of neurotrophins in the mature animal has concerned the possibility that NGF may be a pivotal mediator of inflammation and pain. It has previously been shown that injection of intradermal NGF can result in a neutrophil-dependent hyperalgesia in the rat. The purpose of the present study was to examine the pathological consequence of NGF injected intradermally into mature rat skin and to examine further the role of neutrophils. Standard histopathology techniques (H & E) were employed to determine inflammatory cell counts. Circulating neutrophils were depleted using an anti-rat neutrophil antiserum and results were compared to treatment with vehicle controls. Saline-pretreated rats exhibited normal circulating neutrophil numbers and the dorsal skin showed a significant increase of neutrophil and macrophages at 3 and 5 h and lymphocytes at 5 h after NGF treatment. By comparison, skin sites from neutrophil-depleted rats did not demonstrate a significant increase in neutrophil and macrophage accumulation after NGF administration. All NGF-treated sites, independent of pretreatment, demonstrated abnormal muscle fibre morphology and proliferation of the muscle sarcolemmal nuclei after NGF injection, indicative of tissue injury. In addition, oedema and some fibroplasia were also noted. Furthermore, fibrin production was increased at 3 and 5 h after NGF administration. It is suggested that NGF has a damaging effect on rat muscle which is independent of accumulating neutrophil and other inflammatory cells. In conclusion, the findings indicate a link between NGF-induced neutrophil and macrophage accumulation, as the increase in dermal macrophages was not observed in neutrophil-depleted rats. The results also suggest that NGF can have a profound effect on rat muscle and that this effect may be related to muscle regeneration.