Chiesi Farmaceutici.

No abstract

No abstract

Airway mucus is a complex mixture of secretory products that provides a multifaceted defense against pulmonary infection. Mucus contains antimicrobial peptides (e.g., defensins) and enzymes (e.g., lysozyme) although the contribution of these to airway sterility has not been tested in vivo. We have previously shown that an enzymatically active, heme-containing peroxidase comprises 1% of the soluble protein in sheep airway secretions, and it has been hypothesized that this airway peroxidase may function as a biocidal system. In this study, we show that sheep airway peroxidase is identical to milk lactoperoxidase (LPO) and that sheep airway secretions contain thiocyanate (SCN(-)) at concentrations necessary and sufficient for a functional peroxidase system that can protect against infection. We also show that airway LPO, like milk LPO, produces the biocidal compound hypothiocyanite (OSCN(-)) in vitro. Finally, we show that in vivo inhibition of airway LPO in sheep leads to a significant decrease in bacterial clearance from the airways. The data suggest that the LPO system is a major contributor to airway defenses. This discovery may have significant implications for chronic airway colonization seen in respiratory diseases such as cystic fibrosis.

Allergen-induced bronchoconstriction involves mast cell activation. Tryptase is a mast cell serine protease that is released during this process, but little is known about the action of tryptase in the airway. The purpose of this study was to determine: (1) if aerosolized tryptase causes bronchoconstriction, and (2) the mechanism by which this occurs. We measured mean pulmonary flow resistance (RL) in five allergic sheep before and after consecutive inhalations of 100 and 500 ng tryptase (in 2 ml total volume). Inhaled tryptase at 100 and 500 ng increased RL (mean +/- SE) by 33 +/- 12 and 122 +/- 8% (p < 0.05) over baseline. The response was reproducible upon repeat challenges. These studies were repeated in the same animals after pretreatment with aerosolized APC 366 (9 mg/3 ml), a specific tryptase inhibitor. In APC-366-treated sheep, tryptase increased RL by 10 +/- 3 and 6 +/- 2% (p < 0.05 versus control values) at 100 and 500 ng, respectively. The response to tryptase was also blocked by pretreating the sheep intravenously with the histamine H1-antagonist chlorpheniramine (2 mg/kg), in which RL increased only 5 +/- 4 and 7 +/- 6% after 100 and 500 ng tryptase. APC 366, however, did not block histamine-induced bronchoconstriction. Consistent with these findings was the observation that segmental bronchial challenge with tryptase (1 microgram) resulted in a significant increase in histamine levels in bronchoalveolar lavage. Inhaled tryptase (500 ng) also caused airway hyperresponsiveness to aerosolized carbachol 2 h after tryptase challenge. This tryptase-induced airway hyperresponsiveness could be blocked either by pretreating the sheep with APC 366 (30 min before challenge) or by treating the sheep 30 min after challenge. These results indicate that inhaled tryptase causes bronchoconstriction and airway hyperresponsiveness in allergic sheep by an event that may involve mast cell activation.

Allergic inflammation is the result of a specific pattern of cellular and humoral responses leading to the activation of the innate and adaptive immune system which, in turn, results in physiological and structural changes affecting target tissues such as the airways and the skin. Eosinophils activation and production of soluble mediators such as IgE antibodies is a pivotal feature in the pathophysiology of allergic diseases. In the past few years, however, convincing evidence has shown that neurons and other neurosensory structures are not only a target of the inflammatory process but also participate in the regulation of immune responses by actively releasing soluble mediators. The main products of these activated sensory neurons are a family of protein growth factors called neurotrophins. They were first isolated in the central nervous system and identified as important factors for the survival and differentiation of neurons during fetal and post-natal development as well as neuronal maintenance later in life. Four members of this family have been identified and well defined: nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), neurotrophin 3 (NT-3), and neurotrophin 4/5 (NT-4/5). Neurotrophins play a critical role in the bidirectional signaling mechanisms between immune cells and the neurosensory network structures in the airways and the skin. Pruritus and airway hyperresponsiveness (AHR), two major features of atopic dermatitis and asthma, respectively, are associated with the disruption of the neurosensory network activities. In this review we provide a comprehensive description of the neuroimmune interactions underlying the pathophysiological mechanisms of allergic and inflammatory diseases.

No abstract

There is no solid evidence that any pharmacological treatment reduces mortality in chronic obstructive pulmonary disease (COPD). Two large trials with mortality as an efficacy outcome have been carried out testing a combination of a long-acting beta-agonist (LABA) and an inhaled corticosteroid (ICS) and in both, the reduction in mortality failed to reach statistical significance [1,2]. This could be seen as proof of absence of effect, but given that the TORCH trial [1] resulted in a hazard ratio (HR) of 0.825 (95% CI 0.681-1.002; p=0.052) for the comparison of combined fluticasone propionate and salmeterol with placebo, the interpretation may not be that simple. The other negative trial, the SUMMIT trial [2], only included patients with moderate COPD and increased risk of cardiovascular comorbidity.