Salbutamol: how does it enter smooth muscle cells?

Polyspecific organic cation transporters (OCTs) in human cell membranes are involved in the uptake, distribution and excretion of cationic compounds. Although their relevance to drug disposition in the liver, small intestine and kidney has been investigated previously, less is known about the influence of these transporters on the pharmacokinetics and pharmacodynamics of inhaled drugs. Drugs that are commonly administered by inhalation for the treatment of respiratory diseases, such as glucocorticoids and cationic ß(2)-agonists, might interact with several of these transporters, which are strongly expressed on the surfaces of airway epithelial cells. We evaluated the expression of OCT3 and measured the in vitro uptake of the short-acting ß(2)-agonist salbutamol (SALB), alone or in combination with corticosterone (CS) and beclomethasone dipropionate (BDP), by bronchial smooth muscle cells. Our results showed that these cells express the OCT3 transporter and that SALB enters the cell in a transporter-independent fashion. Moreover, CS and BDP have different activities on SALB transport inside the cell. CS increases SALB transport and BDP decreases SALB transport, although neither of these effects are statistically significant. A better understanding of these mechanisms might lead to the improved treatment of airway diseases.

Anti-proliferative and anti-remodelling effect of beclomethasone dipropionate, formoterol and salbutamol alone or in combination in primary human bronchial fibroblasts.

BACKGROUND: Bronchial asthma is characterized by lower airway inflammation and remodelling. Anti-inflammatory treatment with inhaled corticosteroids (ICS) provides the mainstay of asthma therapy together with bronchodilation induced by short- and long-acting inhaled beta(2)-agonists. Lower airway fibroblasts may play a critical role in airway inflammation and remodelling, suggesting that they might represent an important target for the major anti-asthmatic drugs. The aim of our study was to investigate the effects of beclomethasone dipropionate (BDP), salbutamol and formoterol either alone or in combination on in vitro cultures of human bronchial fibroblasts. METHODS: Fibroblasts were cultured in the presence of pro-inflammatory and proliferative stimuli, BDP, salbutamol and formoterol. The effects of drugs on cell proliferation were ascertained by (3)H-thymidine incorporation. CD90 and CD44 expression were detected by flow cytometry and fibronectin secretion using the enzyme-linked immunosorbent assay technique. RESULTS: This study showed that BDP alone has significant anti-proliferative effects on lung fibroblasts treated with basic fibroblast growth factor and the combination of BDP with formoterol or salbutamol strengthen these effects. Short-acting beta(2)-agonist (SABA) or long-acting beta(2)-agonist (LABA) by themselves did not show any significant effect on the different cultures. CD44 and CD90 expression and fibronectin production were modulated by pro-inflammatory and proliferative stimuli; the addition of the drugs brought them back near to the basal level. CONCLUSIONS: From this in vitro study, we can conclude that BDP, when combined with salbutamol or formoterol, exhibits enhanced anti-remodelling activity in bronchial fibroblasts, providing new insights on the additive effects of ICS and SABAs and LABAs for asthma therapy.

Effect of statins on fibroblasts from human nasal polyps and turbinates.

BACKGROUND: Statins are serum cholesterol-lowering agents used for the prevention and treatment of atherosclerotic vascular disease. There is, however, growing evidence that statins have immunomodulatory and anti-inflammatory activities and may prove invaluable in the treatment of immunological and inflammatory disorders. OBJECTIVE: On these basis we evaluated the effect of statins on the proliferation of fibroblasts derived from human nasal polyps and turbinates and determined their ability to modulate airway remodelling. METHODS: Fluvastatin (0.01-0.1-1 microM), Atorvastatin (0.1-1-10 microM) and Simvastatin (0.1-1-10 microM) were tested on cultured fibroblasts derived from human nasal polyps and turbinates stimulated or not with Fibroblast Growth Factor beta (10 ng/ml). All cultures were treated with 3H-Thymidine (1 microCi/ml) to test cell proliferation. RESULTS: Our results show that proliferation of turbinate-derived fibroblasts is significantly inhibited by the three statins. Fluvastatin is already effective at the lowest dose (0.01 microM), whereas Atorvastatin and Simvastatin act at the plasmatic peak concentration (1 microM). No significant effect was found on fibroblasts derived from nasal polyps, except for Simvastatin which was effective after 144 hours of stimulation. CONCLUSIONS: These drugs show a remarkable antiprolhferative effect and their different outcome depending on the different kind of fibroblasts in vitro is prompting news in the studies about statin use for the treatment of chronic inflammatory diseases.

Levocetirizine in persistent allergic rhinitis and asthma: effects on symptoms, quality of life and inflammatory parameters.

Background Levocetirizine (LCZ) has been shown to be effective in allergic rhinitis. We evaluated its clinical efficacy, antinflammatory actions and its effects on quality of life (QoL) with a specific instrument in the asthma-rhinitis comorbidity. Methods Fifty adult patients with persistent rhinitis with/without asthma were enrolled. After a 1-week run-in for baseline evaluation, they were randomized to LCZ or placebo for 8 weeks. Cromolyn and salbutamol were permitted on demand. Rhinoconjunctivitis and asthma symptoms were evaluated by diary cards. QoL was assessed by the specific Rhinasthma questionnaire and the generic SF-36 at different time-points. Nasal scrapings and lavages were also performed for inflammatory cell count and mediator assessment. Results Ten patients dropped out for unrelated reasons and the remaining completed the study with no side-effect. Symptoms began to decrease in the active group at the second week of treatment when the difference with the placebo group became significant (0.05) and so remained until the end of the trial. Starting from 2 weeks of therapy, there was a significant decrease vs. baseline in all the four components of the Rhinasthma questionnaire only in the active group. The intergroup comparison became significant (P<0.05) at 4 weeks. The SF-36 detected only sporadic differences between groups. Eosinophils and neutrophils in nasal scraping were significantly decreased in the LCZ group vs. baseline at all times. Nasal mediators were under the detection limits and no analysis could be performed. In the active group, only two patients used rescue medications compared with 13 patients in the placebo group. Conclusions LCZ is clinically effective and capable of improving the rhinitis-asthma-related QoL.

Comparison of ELISA for tissue transglutaminase autoantibodies with antiendomysium antibodies in pediatric and adult patients with celiac disease.

BACKGROUND: Tissue transglutaminase (t-TG) is the main autoantigen recognized by the endomysium antibodies (EMA) observed in patients with celiac disease (CD). The aim of the study was to assess an ELISA method for t-TG antibodies (t-TGA) with respect to EMA IF assay in pediatric and adult patients. METHODS: t-TGA were analyzed by ELISA in 220 sera samples: 82 patients with biopsy-proven untreated CD (23 adults and 59 children), 14 CD children on gluten-free diet, 18 asymptomatic relatives of CD patients, and 106 age-matched control patients with gluten-unrelated gastrointestinal diseases (58 adults and 48 children). Serum IgA EMA were tested on umbilical cord sections in all patients. RESULTS: The great majority (92.7%) of untreated CD patients (both adults and children) were t-TGA positive (values ranging from 20.1 to > 300 AU). None of the child control patients and only two out of 58 (3.4%) of the adults with unrelated gastrointestinal diseases had serum t-TGA positivity; two out of 18 first-degree relatives with biopsy-proved silent CD were t-TGA (as well as EMA) positive. Finally, two out of 14 CD children, assuming a gluten-free diet, had serum t-TGA (as well as EMA). A highly significant correlation (P < 0.001) was observed between t-TGA concentrations and EMA. t-TGA showed a sensitivity of 87% and 95%, a specificity of 97% and 100% for adults and children, respectively. CONCLUSION: The method is highly sensitive and specific in the diagnosis of CD and is promising as a tool for routine diagnostic use and population screening, especially in children.