Sa Marsico

Increased activation of p38 MAPK in COPD

Inflammation, oxidative stress and apoptosis, which are involved in chronic obstructive pulmonary disease (COPD) pathogenesis, may activate the p38 subgroup of mitogen-activated protein kinases (MAPKs). Therefore, the aim of the present study was to evaluate the expression of the phosphorylated, active form of p38 MAPK (phospho-p38) in the lungs of COPD patients. Surgical specimens were obtained from 18 smokers with COPD at different stages of disease severity, plus nine smoking and eight nonsmoking subjects with normal lung function. Phospho-p38+ cells were quantified by immunohistochemistry in both alveolar spaces and alveolar walls. Moreover, a Western blot analysis of phospho-p38 and total p38α isoform expressed by alveolar macrophages was performed. Phospho-p38+ alveolar macrophages and phospho-p38+ cells in alveolar walls were increased in patients with severe and mild/moderate COPD, compared with smoking and nonsmoking controls. Moreover, they were inversely correlated to values of forced expiratory volume in one second (FEV1) and FEV1/forced vital capacity. Western blot analysis showed that phosphorylated p38, but not the total p38α isoform, was specifically increased in alveolar macrophages from COPD patients. Activation of the p38 mitogen-activated protein kinase pathway appears to be involved in the pathogenesis of chronic obstructive pulmonary disease. The present findings suggest that this protein may be a suitable pharmacological target for therapeutic intervention.

Molecular mechanisms of corticosteroid actions in chronic inflammatory airway diseases.

Although corticosteroids have been used for a long time as a very effective therapy of airway inflammatory diseases such as asthma, only recently the molecular basis of their mechanism of action has begun to be elucidated. These hormones exert their biological and pharmacological actions by binding to cytoplasmic receptors that, upon activation, translocate to the nucleus where they interact with specific genomic sequences thus modulating gene expression. However, many glucocorticoid effects responsible for their anti-inflammatory and anti-asthmatic activity take place irrespectively of receptor binding to DNA. In particular, ligand-bound glucocorticoid receptors can repress several different pro-inflammatory genes by physically associating, via protein-protein interactions, with various transcription factors and with the macromolecular complexes implicated in regulation of chromatin structure and function. In this regard, an important role is played by the influences of corticosteroids on the intrinsic histone acetyltransferase and deacetylase functions of coactivators and corepressors, respectively. Furthermore, the signal transduction pathways mediated by mitogen-activated protein kinases are newly recognized, key targets of glucocorticoids. Indeed, these enzymatic cascades are crucially involved in the regulation of gene expression in that they are essential for the activity of a high number of transcription factors. Therefore, the recent advances made in such a rapidly growing research field are providing new insights into the mode of action of corticosteroids, thereby also unveiling novel promising therapeutic strategies directly targeted to the molecular events underlying the inflammatory, immune, and apoptotic processes implicated in the pathogenesis of asthma and other airway diseases.

Effects of budesonide on P38 MAPK activation, apoptosis and IL-8 secretion, induced by TNF-alpha and Haemophilus influenzae in human bronchial epithelial cells.

Non-typeable Haemophilus influenzae (NTHi) is one of the most frequently involved pathogens in bacterial exacerbations of chronic obstructive pulmonary disease (COPD). In the airways, the main tissue target of NTHi is bronchial epithelium, where this pathogen can further amplify the inflammatory and structural changes induced by proinflammatory cytokines such as tumour necrosis factor-α (TNF-α). Therefore, the aim of this study is to investigate, in primary cultures of human bronchial epithelial cells, the effects of NTHi on signal transduction pathways, apoptotic events and chemokine production activated by TNF-α. Moreover, we also evaluated the effects exerted on such cellular and molecular phenomena by a corticosteroid drug. p38 mitogen-activated protein kinase (MAPK) phosphorylation was analyzed by Western blotting, using an anti-phospho-p38 MAPK monoclonal antibody. Apoptosis was assayed by active caspase-3 expression. Interleukin-8 (IL-8/CXCL8) was detected in cell-free culture supernatants by ELISA. TNF-α induced a significant increase in p38 MAPK phosphorylation. NTHi was able to potentiate the stimulatory actions of TNF-α on caspase-3 expression and, to a lesser extent, on IL-8 secretion. These effects were significantly (P < 0.01) inhibited by a pharmacological pre-treatment with budesonide. These results suggest that TNF-a is able to stimulate, via activation of p38 MAPK signalling pathway, IL-8 release and airway epithelial cell apoptosis; the latter effect can be markedly potentiated by NTHi. Furthermore, budesonide can be very effective in preventing, through inhibition of p38 MAPK phosphorylation, both structural and proinflammatory changes elicited in bronchial epithelium by TNF-α and NTHi.

New perspectives in asthma treatment.

The recent advances in the knowledge of the basic mechanisms underlying asthmatic inflammation have significantly contributed to the delineation of new therapeutic perspectives for asthma. There are currently three main approaches to the development of novel antiasthma treatments:

Snail ingestion and asthma.

EVERAL CASES of allergic reactions which take S place within a few minutes or hours after food ingestion have been reported. These reactions can trigger gastrointestinal, cutaneous, and/or respiratory symptoms. In some patients, respiratory symptoms occur when cross-reactivity between ingested food and inhaled allergens is present ( 1, 2). Our observaticns refer to four atopic subjects allergic to house-dust mite who unexpectedly experienced severe asthma attacks after snail (Limax agrestis) ingestion.

T cell activation state in the induced sputum of asthmatics treated with budesonide

Bronchial hyperresponsiveness and airway infiltration with eosinophils and T lymphocytes are key features of asthma. In particular, CD4+ T cells are currently believed to play a pivotal role as initiators and coordinators of the asthmatic inflammatory response and, therefore, they represent a crucial target of corticosteroid treatment. The aim of the present investigation is thus to evaluate, in patients with mild asthma, the effects of inhaled corticosteroid therapy on the following parameters: (i) functional state of CD4+ T cells; (ii) airway eosinophilia; (iii) bronchial hyperresponsiveness to methacholine. The study was completed by twenty asthmatic, atopic subjects, subdivided into two groups of ten and treated for 12 weeks with either inhaled budesonide (200 μg twice daily) or terbutaline alone (500 μg twice daily), respectively. Expression of CD4+ T cell activation markers was measured in induced sputum at baseline and after 1, 4, 8 and 12 weeks of treatment by flow cytometry, which showed a down-regulation of HLA-DR and CD25 surface proteins in the budesonide group, compared with the control group; these differences resulted as being statistically significant through weeks 4–12. Budesonide also induced a quick, sharp reduction in the percentage of eosinophils detectable in induced sputum, as well as a more gradual progressive improvement in airway hyperresponsiveness to methacholine. Therefore, in addition to assessing various indices of bronchial inflammation, flow cytometry can be reliably applied to induced sputum in order to monitor, even in mildly symptomatic patients, the effects of anti-asthma treatments on T cell activation.

Effects of betamethasone on theophylline disposition in man are saliva values predictive of serum theophylline levels

The pharmacokinetic interaction between betamethasone (5 mg/day for 5 days) and theophylline (3.35 mg/kg orally before and after betamethasone treatment) was studied in 13 female patients evaluating saliva and serum theophylline concentrations by means of an enzyme multiplied immunoassay technique. Betamethasone treatment did not significantly change saliva and serum theophylline levels. As regards the potential usefulness of saliva theophylline levels in predicting the concomitant serum concentrations of the bronchodilator, in spite of the significant correlation found in our study (r = 0.758; P less than 0.001), we think that, using individual saliva values, there is a poor predictive value for serum theophylline concentrations.