Distribution of inhaled fluticasone propionate between human lung tissue and serum in vivo

Pharmacological Basis of Differences in Dose Response, Dose Equivalence, and Duration of Action of Inhaled Corticosteroids

INTRODUCTION

Asthma treatment guidelines classify inhaled corticosteroid (ICS) regimens as low, medium, or high dose. However, efficacy and safety are not independently assessed accordingly. Moreover, differences in ICS duration of action are not considered when a dose regimen is selected. We investigated the efficacy and safety implications of these limitations for available ICS molecules.

METHODS

Published pharmacodynamic and pharmacokinetic parameters were used, alongside physiological and pharmacological principles, to estimate the efficacy and safety of available ICS molecules. Extent and duration of glucocorticoid receptor (GR) occupancy in the lung (efficacy) and cortisol suppression (systemic exposure and safety) were estimated.

RESULTS

Some ICS regimens (e.g., fluticasone furoate, fluticasone propionate, and ciclesonide) rank high for efficacy but low for systemic exposure, contrary to how ICS dose equivalence is currently viewed. Differences in dose-response relationships for efficacy and systemic exposure were unique for each ICS regimen and reflected in their therapeutic indices. Notably, even low doses of most ICSs can generate high GR occupancy (≥ 90%) across the entire dose interval at steady state, which may explain previously reported difficulties in obtaining dose responses within the clinical dose range and observations that most clinical benefit typically occurs at low doses. The estimated post dose duration of lung GR occupancy for ICS molecules was categorized as 4-6 h (short), 14-16 h (medium), 25-40 h (long), or > 80 h (ultra-long), suggesting potentially large differences in anti-inflammatory duration of action.

CONCLUSION

In a real-world clinical setting where there may be poor adherence to prescribed therapy, our findings suggest a significant therapeutic advantage for longer-acting ICS molecules in patients with asthma.

Pharmacokinetic Models for Inhaled Fluticasone Propionate and Salmeterol Xinafoate to Quantify Batch-to-Batch Variability

Advair Diskus is an essential treatment for asthma and chronic obstructive pulmonary disease. It is a dry powder inhaler with a combination of fluticasone propionate (FP) and salmeterol xinafoate (SX). However, the pharmacokinetics (PK) batch-to-batch variability of the reference-listed drug (RLD) hindered its generic product development. This work developed the PK models for inhaled FP and SX that could represent potential batch variability. Two batches each of the reference and the test product (R1, R2, T1, T2) of Advair Diskus (100 μg FP/50 μg SX inhalation) were administered to 60 healthy subjects in a 4-period, 4-sequence crossover study. The failure of the bioequivalence (BE) between R1 and R2 confirmed the high between-batch variability of the RLD. Non-linear mixed effect modeling was used to estimate the population mean PK parameters for each batch. For FP, a 2-compartment model with a sequential dual zero-order absorption best described the PK profile. For SX, a 2-compartment model with a first-order absorption model best fit the data. Both models were able to capture the plasma concentration, the maximum concentration, and the total exposure (AUCinf) adequately for each batch, which could be used to simulate the BE study in the future. In vitro properties were also measured for each batch, and the batch with a higher fraction of the fine particle (diameter < 1 µm, < 2 µm) had a higher AUCinf. This positive correlation for both FP and SX could potentially assist the batch selection for the PK BE study.

Fluticasone/formoterol compared with other ICS/LABAs in asthma: a systematic review

OBJECTIVES

An inhaled corticosteroid (ICS)-long-acting beta-2 agonist (LABA) combination has become the standard of care in asthma. Various ICS-LABAs are commercially available providing the clinician with many choices. A thorough understanding of the clinical efficacy and safety of various formulations will immensely benefit the prescribing doctor to decide the choice of agent. The present systematic review was undertaken to compare the clinical efficacy and safety of formoterol fluticasone (FF) to other ICS/LABA combinations in asthmatics.

METHODS

The review adhered to the general principles mentioned in the CRD guidance and the PRISMA statement. We searched Medline, Embase, and Cochrane Controlled Trials Register databases on the efficacy of FF in treating asthma compared with other ICS-LABAs. A total of 138 trials identified initially. Only trials comparing the efficacy and safety of FF in comparision with Salmeterol/fluticasone (SF) or Budesonide/Formoterol (BF) were selected. The outcomes compared were onset of bronchodilator action, improvement in lung function, asthma control, asthma-related quality of life and risk of pneumonia.

RESULTS

Sixteen studies were included in the final analysis. FF therapy provided faster onset of bronchodilatation than SF. A better improvement in lung function was seen with FF inhaler use as compared with comparators in two studies. Patients using the FF inhaler had a non-inferior asthma control and asthma-related quality of life. Pneumonia risk was least with FF usage.

CONCLUSION

FF provides faster onset of action, numerically superior improvement in lung function and comparable asthma control than other ICS-LABA formulations. FF has better safety evidenced by lower occurrence of pneumonia.

Fluticasone Particles Bind to Motile Respiratory Cilia: A Mechanism for Enhanced Lung and Systemic Exposure?

Background: Inhaled corticosteroids (ICSs) are the main prophylactic treatment for asthma and are used in other diseases, including chronic pulmonary obstructive disease, yet the interaction of ICS particles with the ciliated epithelium remains unclear. The aim of this study was to investigate the earliest interaction of aerosolized fluticasone propionate (FP) particles with human ciliated respiratory epithelium. Methods: A bespoke system was developed to allow aerosolized FP particles to be delivered to ciliated epithelial cultures by nebulization and from a pressurized metered-dose inhaler (pMDI) through a spacer with interactions observed in real time using high-speed video microscopy. Interaction with nonrespiratory cilia was investigated using steroids on brain ependymal ciliary cultures. The dissolution rate of steroid particles was determined. Results: FP particles delivered by aerosol attached to the tips of rapidly beating cilia. Within 2 hours, 8.7% ± 1.8% (nebulization) and 12.1% ± 2.1% (pMDI through spacer) of ciliated cells had one or more particles attached to motile cilia. These levels decreased to 5.8% ± 1.6% (p = 0.59; nebulization) and 5.3% ± 2.2% (p = 0.14; pMDI through spacer) at 24 hours. Particle attachment did not affect ciliary beat frequency (p > 0.05) but significantly (p < 0.001) reduced ciliary beat amplitude. Steroid particles also attached to the tips of motile ependymal brain cilia and also reduced beat amplitude (24 hours: >2 particles bound p < 0.001). Dissolution of FP particles was slow with only 22.8% ± 1.3% of nebulized and 12.8% ± 0.5% of pMDI-delivered drug dissolving by 24 hours. Conclusions: FP particles adhere to the tips of rapidly moving cilia with significant numbers remaining bound at 24 hours, resisting the shear stress generated by ciliary beating. In vivo, this mechanism may predispose to high local drug concentrations and enhance respiratory and systemic corticosteroid exposure.

Inhaled Formoterol-Fluticasone Single Inhaler Therapy in Asthma: Real-World Efficacy, Budget Impact, and Potential to Improve Adherence

Asthma is the commonest chronic disease affecting airways in humans and has an increasing global disease burden. Inhaled corticosteroids (ICS) are the first-line therapeutic option for asthma, and addition of a long-acting beta 2-agonist (LABA) has been shown to improve asthma control. A combination of the two agents in a single inhaler is beneficial with regard to ease of administration and patient compliance. Various ICS-LABA formulations are available across various countries in the world, one among them being formoterol-fluticasone. Both formoterol and fluticasone have pharmacologic peculiarities which places the combination in a uniquely advantageous position when it comes to asthma therapy. The present review focuses on some of the, hitherto, less explored aspects of this combination inhaler such as real-world efficacy, impact on budget allocation, results of switch-over therapy, and potential to improve adherence to asthma treatment. It also provides practical recommendations on positioning it in real-world asthma management.

Effects of corticosteroids on COPD lung macrophage phenotype and function

The numbers of macrophages are increased in the lungs of chronic obstructive pulmonary disease (COPD) patients. COPD lung macrophages have reduced ability to phagocytose microbes and efferocytose apoptotic cells. Inhaled corticosteroids (ICSs) are widely used anti-inflammatory drugs in COPD; however, their role beyond suppression of cytokine release has not been explored in COPD macrophages. We have examined the effects of corticosteroids on COPD lung macrophage phenotype and function. Lung macrophages from controls and COPD patients were treated with corticosteroids; effects on gene and protein expression of CD163, CD164, CD206, MERTK, CD64, CD80 and CD86 were studied. We also examined the effect of corticosteroids on the function of CD163, MERTK and cluster of differentiation 64 (CD64). Corticosteroid increased CD163, CD164, CD206 and MERTK expression and reduced CD64, CD80 and CD86 expression. We also observed an increase in the uptake of the haemoglobin-haptoglobin complex (CD163) from 59 up to 81% and an increase in efferocytosis of apoptotic neutrophils (MERTK) from 15 up to 28% following corticosteroid treatment. We observed no effect on bacterial phagocytosis. Corticosteroids alter the phenotype and function of COPD lung macrophages. Our findings suggest mechanisms by which corticosteroids exert therapeutic benefit in COPD, reducing iron available for bacterial growth and enhancing efferocytosis.

Biological Obstacles for Identifying In Vitro-In Vivo Correlations of Orally Inhaled Formulations

Oral inhalation of drugs is the classic therapy of obstructive lung diseases. In contrast to the oral route, the link between in vitro and in vivo findings is less well defined and predictive models and parameters for in vitro-in vivo correlations are missing. Frequently used in vitro models and problems in obtaining in vivo values to establish such models and to identify the action of formulations in vivo are discussed. It may be concluded that major obstacles to link in vitro parameters on in vivo action include lack of treatment adherence and incorrect use of inhalers by patients, variation in inhaler performance, changes by humidity, uncertainties about lung deposition, and difficulties to measure drug levels in epithelial lining fluid and tissue. Physiologically more relevant in vitro models, improvement in inhaler performance, and better techniques for in vivo measurements may help to better understand importance and interactions between individual in vitro parameters in pulmonary delivery.

Drug Concentration Asymmetry in Tissues and Plasma for Small Molecule-Related Therapeutic Modalities

The well accepted "free drug hypothesis" for small-molecule drugs assumes that only the free (unbound) drug concentration at the therapeutic target can elicit a pharmacologic effect. Unbound (free) drug concentrations in plasma are readily measurable and are often used as surrogates for the drug concentrations at the site of pharmacologic action in pharmacokinetic-pharmacodynamic analysis and clinical dose projection in drug discovery. Furthermore, for permeable compounds at pharmacokinetic steady state, the free drug concentration in tissue is likely a close approximation of that in plasma; however, several factors can create and maintain disequilibrium between the free drug concentration in plasma and tissue, leading to free drug concentration asymmetry. These factors include drug uptake and extrusion mechanisms involving the uptake and efflux drug transporters, intracellular biotransformation of prodrugs, membrane receptor-mediated uptake of antibody-drug conjugates, pH gradients, unique distribution properties (covalent binders, nanoparticles), and local drug delivery (e.g., inhalation). The impact of these factors on the free drug concentrations in tissues can be represented by K _p,uu, the ratio of free drug concentration between tissue and plasma at steady state. This review focuses on situations in which free drug concentrations in tissues may differ from those in plasma (e.g., K _p,uu > or <1) and discusses the limitations of the surrogate approach of using plasma-free drug concentration to predict free drug concentrations in tissue. This is an important consideration for novel therapeutic modalities since systemic exposure as a driver of pharmacologic effects may provide limited value in guiding compound optimization, selection, and advancement. Ultimately, a deeper understanding of the relationship between free drug concentrations in plasma and tissues is needed.

Estimation of Fraction Dissolved After Intratracheal Delivery of a Potent Janus Kinase Inhibitor, iJAK-001, with Low Solubility in Rat and Sheep: Impact of Preclinical PKPD on Inhaled Human Dose Projection

Background: A highly potent pan-Janus kinase (JAK) inhibitor with excellent kinome selectivity was developed for topical delivery to treat severe asthma. This poorly soluble drug discovery candidate, iJAK-001, is expected to exhibit long duration of JAK/STAT pathway inhibition at low doses in asthmatics because of depot effect after dry powder inhalation. Human dose projection for inhaled molecules with low aqueous solubility remains to be a daunting challenge because of several limitations: (1) bioanalytical measurement of dissolved fraction after inhalation of solid particles is uncertain; (2) distribution of these particles is not homogenous in the lung; (3) in vitro solubility measurements to estimate fraction dissolved may not be a reflection of local surface lung concentration; (4) lack of a surrogate biomarker of lung target engagement, and (5) invasive procedure needed to sample human lung tissue in the clinic. Methods: We leveraged in silico, in vitro, and in vivo tools preclinically and found significant differences in lung to plasma partition ratio when iJAK-001 was given intravenously (IV) or intratracheally in a solution-based formulation versus that in suspension, as well as pharmacodynamic response in preclinical asthma models when delivered systemically via IV infusion versus inhaled. Results and Conclusion: The combined results from above suggest that caution must be exercised using either lung or plasma exposure for human dose projection. Instead, using the local inhibitor concentration estimate based on delivery efficiency, dose, fraction absorbed, and rate of absorption normalized by lung (cardiac) blood flow may be more appropriate for dose projection.

Effects of fluticasone propionate and budesonide on the expression of immune defense genes in bronchial epithelial cells

BACKGROUND

COPD patients have increased risk of pneumonia when treated with fluticasone propionate (FP), whereas this is generally not the case with budesonide (BUD) treatment. We hypothesized that BUD and FP differentially affect the expression of immune defense genes.

METHODS

Human bronchial epithelial 16HBE cells and air-liquid interface (ALI)-cultured primary bronchial epithelial cells (PBECs) were pre-treated with clinically equipotent concentrations of BUD or FP (0.16-16 nM BUD and 0.1-10 nM FP), and the expression of immune defense genes was studied at baseline and after exposure to rhinovirus (RV16).

RESULTS

Using microfluidic cards, we observed that both BUD and FP significantly suppressed CXCL8, IFNB1 and S100A8 mRNA expression in unstimulated 16HBE cells. Interestingly, BUD, but not FP, significantly increased lactotransferrin (LTF) expression. The difference between the effect of BUD and FP on LTF expression was statistically significant and confirmed by qPCR and at the protein level by western blotting. RV16 infection of ALI-cultured PBECs significantly increased the expression of CCL20, IFNB1 and S100A8, but not of LTF or CAMP/LL-37. In these RV16-exposed cells, LTF expression was again significantly higher upon pre-treatment with BUD than with FP. The same was observed for S100A8, but not for CCL20, IFNB1 or CAMP/LL-37 expression.

CONCLUSIONS

Treatment of human bronchial epithelial cells with BUD results in significantly higher expression of specific immune defense genes than treatment with FP. The differential regulation of these immune defense genes may help to explain the clinical observation that BUD and FP treatment differ with respect to the risk of developing pneumonia in COPD.

Inhalation Therapy in Horses

This article discusses the benefits and limitations of inhalation therapy in horses. Inhalation drug therapy delivers the drug directly to the airways, thereby achieving maximal drug concentrations at the target site. Inhalation therapy has the additional advantage of decreasing systemic side effects. Inhalation therapy in horses is delivered by the use of nebulizers or pressured metered dose inhalers. It also requires the use of a muzzle or nasal mask in horses. Drugs most commonly delivered through inhalation drug therapy in horses include bronchodilators, antiinflammatories, and antimicrobials.

17-oxo-DHA displays additive anti-inflammatory effects with fluticasone propionate and inhibits the NLRP3 inflammasome

Chronic obstructive pulmonary disease (COPD) is characterized by reduced lung function associated with increased local and systemic inflammatory markers, such as TNFα and IL-1β. Glucocorticoids are used to treat this chronic disease, however their efficacy is low and new drugs are very much required. 17-oxo-DHA is a cyclooxygenase-2-dependent, electrophilic, α,β-unsaturated keto-derivative of docosahexaenoic acid with anti-inflammatory properties. We evaluated the action of 17-oxo-DHA alone or in combination with the steroid fluticasone propionate (FP) in peripheral blood mononuclear cells (PBMCs) from COPD patients and healthy individuals exposed to lipopolysaccharide. We show that PBMCs from COPD patients released higher levels of TNFα and IL-1β compared to controls. 17-oxo-DHA displayed strong anti-inflammatory effects. The addition of 17-oxo-DHA in combination with FP showed enhanced anti-inflammatory effects through the modulation of transcriptional and post-transcriptional mechanisms. 17-oxo-DHA, but not FP, was able to suppress the release of mature IL-1β through inhibition of the NLRP3 inflammasome. Furthermore, 17-oxo-DHA inhibited inflammasome-dependent degradation of the glucocorticoid receptor (GR). Our findings suggest that 17-oxo-DHA in combination with FP or other steroids might achieve higher therapeutic efficacy than steroids alone. Combined treatment might be particularly relevant in those conditions where increased inflammasome activation may lead to GR degradation and steroid-unresponsive inflammation.

Pharmacodynamic and pharmacokinetic considerations in choosing an inhaled corticosteroid

Inhaled corticosteroids are effective in controlling airway inflammation. Their anti-inflammatory effect is primarily topical, at the site of deposition in the airways. Consequently, traditional pharmacodynamic and pharmacokinetic concepts, which rely on measuring blood concentrations of drug, have limited applicability for evaluating the efficacy of topically acting inhaled corticosteroids. Important factors affecting efficacy of inhaled corticosteroids are: (i) intrinsic properties of the drugs, particularly their affinity for the corticosteroid receptor; and (ii) the newer pharmacodynamic concept of deposition characteristics of the drug formulation. Small particle formulations, especially those developed in the metered-dose inhaler with the new hydrofluoroalkane propellant, deposit to a much greater extent in the lung and may consequently have improved clinical efficacy. Lipid conjugation of inhaled corticosteroids within the lung may allow prolonged duration of effect, enabling once-daily administration. Pharmacodynamic and pharmacokinetic principles probably do not play a role in describing upper airway adverse effects occurring with inhaled corticosteroids. These are probably also determined by intrinsic properties of the drug and deposition characteristics. However, pharmacodynamic and pharmacokinetic principles seem to be important in addressing systemic safety concerns with inhaled corticosteroids. Those inhaled corticosteroids with a longer serum half-life, especially if they have higher affinity for the corticosteroid receptor, may be associated with greater systemic effects. A new pharmacokinetic concept suggests that increased protein binding within the systemic circulation and high systemic clearance of an inhaled corticosteroid may reduce the risk for systemic effects. These new pharmacodynamic and pharmacokinetic concepts provide a useful framework for identifying the characteristics of an inhaled corticosteroid with an improved benefit-to-risk profile. Increased lung deposition and reduced deposition in the upper airway should result in an inhaled corticosteroid with favorable clinical efficacy and a decreased risk for topical upper airway adverse effects. An inhaled corticosteroid with high plasma protein binding and rapid clearance might pose much less risk for systemic adverse effects than currently available drugs in this class.

Anti-inflammatory effects of the novel inhaled phosphodiesterase type 4 inhibitor CHF6001 on virus-inducible cytokines

Respiratory virus infections precipitate asthma and chronic obstructive pulmonary disease (COPD) exacerbations, with most exacerbations due to rhinovirus infection. Both asthma and COPD exacerbations are not well controlled by steroid therapies, and there is a much research interest in finding improved therapies or combinations of therapies for controlling exacerbations. CHF6001 is a new, inhaled highly potent and selective phosphodiesterase type 4 (PDE4) inhibitor. Using in vitro human bronchial epithelial cells (BEAS‐2B), we investigated the potential anti‐inflammatory effects of CHF6001 on rhinovirus (RV1B)‐induced cytokines. Cytokine mRNA was measured by real‐time PCR, while protein release was measured by ELISA. CHF6001 was used in a 7‐point dose–response curve (1000–0.001 nmol/L) as a 1.5‐h pretreatment prior to infection in comparison with roflumilast. Both roflumilast and CHF6001 reduced RV1B‐induced IL‐8, IL‐29, IP‐10, and RANTES mRNA and protein in a concentration‐dependent manner. Generally, CHF6001 was 13‐ to 16‐fold more potent (subnanomolar EC₅₀ values) than roflumilast at reducing IL‐8, IL‐29, IP‐10, and RANTES mRNA and protein release, but had similar efficacies. In combination with the steroid fluticasone propionate (1 nmol/L), CHF6001 had additive effects, significantly reducing RV‐induced cytokines when compared with steroid or CHF6001 alone. Combined low‐dose steroid and low‐dose CHF6001 had a similar efficacy as high‐dose steroid or CHF6001 alone, indicating the combination had steroid and PDE4 inhibitor sparing effects. Overall results indicate that PDE4 inhibitors have anti‐inflammatory activity against virus‐induced inflammatory mediators and that CHF6001 is more potent than roflumilast.

The effects of corticosteroids on COPD lung macrophages: a pooled analysis

BACKGROUND

There is large variation in the therapeutic response to inhaled corticosteroids (ICS) in COPD patients. We present a pooled analysis of our previous studies investigating the effects of corticosteroids on lung macrophages, in order to robustly determine whether corticosteroid sensitivity in COPD cells is reduced compared to controls, and also to evaluate the degree of between individual variation in drug response.

METHODS

Data from 20 never smokers (NS), 27 smokers (S) and 45 COPD patients was used. Lung macropahges had been stimulated with lipopolysaccharide (LPS), with or without the corticosteroid dexamethasone, and tumour necrosis factor (TNF)-α, interleukin (IL)-6 and chemokine C-X-C motif ligand (CXCL) 8 production was measured.

RESULTS

There was no difference in the anti-inflammatory effects of corticosteroids when comparing group mean data of COPD patients versus controls. The inhibition of TNF-α and IL-6 was greater than CXCL8. The effects of corticosteroids varied considerably between subjects, particularly at lower corticosteroid concentrations.

CONCLUSIONS

We confirm that overall corticosteroid sensitivity in COPD lung macrophages is not reduced compared to controls. The varied effect of corticosteroids between subjects suggests that some individuals have an inherently poor corticosteroid response. The limited suppression of lung macrophage derived CXCL8 may promote neutrophilic inflammation in COPD.

Incident pneumonia and mortality in patients with chronic obstructive pulmonary disease. A double effect of inhaled corticosteroids?

Inhaled corticosteroids are commonly prescribed for patients with severe chronic obstructive pulmonary disease. Although their use improves quality of life and reduces exacerbations, it is associated with increased risk of pneumonia. Curiously, their use has not been associated with increased risk of pneumonia-related or overall mortality. We review pertinent literature to further explore the effects of inhaled corticosteroids on incident pneumonia and mortality in patients with chronic obstructive pulmonary disease. The association of use of inhaled corticosteroids and incident pneumonia is substantial and has been present in the majority of the studies on the topic. This includes both randomized controlled trials and observational studies. However, all of the studies have substantial risk of bias. Most randomized trials are limited by lack of systematic ascertainment of pneumonia; they depended on adverse event reporting. Many observational studies included proper radiographic assessment of pneumonia, but they are limited by their retrospective, observational design. The unadjusted higher risk of pneumonia is associated with longer duration of use, more potent ICS compounds, and higher doses. That implies a dose-effect relationship. Unlike pneumonia, mortality is a precise outcome. Despite the robust association of inhaled corticosteroid use with increased risk of pneumonia, all studies find either no difference or a reduction in pulmonary-related and overall mortality associated with the use of inhaled corticosteroids. These observations suggest a double effect of inhaled corticosteroids (i.e., an adverse effect plus an unexplained mitigating effect).

In vitro and in vivo performance of dry powder inhalation formulations: comparison of particles prepared by thin film freezing and micronization

Recently, inhaled immunosuppressive agents have attracted increasing attention for maintenance therapy following lung transplantation. The rationale for this delivery approach includes a more targeted and localized delivery to the diseased site with reduced systemic exposure, potentially leading to decreased adverse side effects. In this study, the in vitro and in vivo performance of an amorphous formulation prepared by thin film freezing (TFF) and a crystalline micronized formulation produced by milling was compared for tacrolimus (TAC). Despite the relatively large geometric size, the TFF-processed formulation was capable of achieving deep lung delivery due to its low-density, highly porous, and brittle characteristics. When emitted from a Miat® monodose inhaler, TFF-processed TAC formulations exhibited a fine particle fraction (FPF) of 83.3% and a mass median aerodynamic diameter (MMAD) of 2.26 μm. Single-dose 24-h pharmacokinetic studies in rats demonstrated that the TAC formulation prepared by TFF exhibited higher pulmonary bioavailability with a prolonged retention time in the lung, possibly due to decreased clearance (e.g., macrophage phagocytosis), compared to the micronized TAC formulation. Additionally, TFF formulation generated a lower systemic TAC concentration with smaller variability than the micronized formulation following inhalation, potentially leading to reduced side effects related to the drug in systemic circulation.

Prehospital use of inhaled corticosteroids and point prevalence of pneumonia at the time of hospital admission: secondary analysis of a multicenter cohort study

OBJECTIVE

To address clinical concern regarding the use of inhaled corticosteroids (ICSs) and the risk for pneumonia, particularly among patients with chronic obstructive pulmonary disease (COPD) and asthma.

PATIENTS AND METHODS

A multicentered prospective cohort of patients admitted to the hospital from March 1, 2009, through August 31, 2009, with pneumonia or another risk factor for acute respiratory distress syndrome was analyzed to determine the risk for pneumonia requiring hospitalization among patients taking ICSs. The adjusted risk (odds ratio [OR]) for developing pneumonia because of ICSs was determined in a multiple logistic regression model.

RESULTS

Of the 5584 patients in the cohort, 495 (9%) were taking ICSs and 1234 (22%) had pneumonia requiring hospitalization. In univariate analyses, pneumonia occurred in 222 (45%) of the patients on ICSs vs 1012 (20%) in those who were not (OR, 3.28; 95% CI, 2.71-3.96; P<.001). After adjusting in the logistic regression model, prehospital ICS use was not significantly associated with pneumonia in the whole cohort (OR, 1.20; 95% CI, 0.93-1.53; P=.162), among the subset of 589 patients with COPD (OR, 1.40; 95% CI, 0.95-2.09; P=.093), among the 440 patients with asthma (OR, 1.07; 95% CI, 0.61-1.87; P=.81), nor among the remaining 4629 patients without COPD or asthma (OR, 1.32; 95% CI, 0.88-1.97; P=.179).

CONCLUSION

When adjusted for multiple confounding variables, ICS use was not substantially associated with an increased risk for pneumonia requiring admission in our cohort.

Chronic exposure to glucocorticoids shapes gene expression and modulates innate and adaptive activation pathways in macrophages with distinct changes in leukocyte attraction

Glucocorticoids (GCs) have been used for more than 50 y as immunosuppressive drugs, yet their efficacy in macrophage-dominated disorders, such as chronic obstructive pulmonary disease, is debated. Little is known how long-term GC treatment affects macrophage responses in inflammatory conditions. In this study, we compared the transcriptome of human macrophages, matured in the presence or absence of fluticasone propionate (FP), and their ability to initiate or sustain classical activation, mimicked using acute LPS and chronic IFN-γ stimulation, respectively. We identified macrophage gene expression networks, modulated by FP long-term exposure, and specific patterns of IFN-γ- and LPS-induced genes that were resistant, inhibited, or exacerbated by FP. Results suggest that long-term treatment with GCs weakens adaptive immune signature components of IFN-γ and LPS gene profiles by downmodulating MHC class II and costimulatory molecules, but strengthens innate signature components by maintaining and increasing expression of chemokines involved in phagocyte attraction. In a mouse model of chronic obstructive pulmonary disease, GC treatment induced higher chemokine levels, and this correlated with enhanced recruitment of leukocytes. Thus, GCs do not generally suppress macrophage effector functions, but they cause a shift in the innate-adaptive balance of the immune response, with distinct changes in the chemokine-chemokine receptor network.

Inhaled corticosteroids in COPD and the risk of serious pneumonia

Background

Inhaled corticosteroids (ICS) are known to increase the risk of pneumonia in patients with chronic obstructive pulmonary disease (COPD). It is unclear whether the risk of pneumonia varies for different inhaled agents, particularly fluticasone and budesonide, and increases with the dose and long-term duration of use.

Methods

We formed a new-user cohort of patients with COPD treated during 1990–2005. Subjects were identified using the Quebec health insurance databases and followed through 2007 or until a serious pneumonia event, defined as a first hospitalisation for or death from pneumonia. A nested case–control analysis was used to estimate the rate ratio (RR) of serious pneumonia associated with current ICS use, adjusted for age, sex, respiratory disease severity and comorbidity.

Results

The cohort included 163 514 patients, of which 20 344 had a serious pneumonia event during the 5.4 years of follow-up (incidence rate 2.4/100/year). Current use of ICS was associated with a 69% increase in the rate of serious pneumonia (RR 1.69; 95% CI 1.63 to 1.75). The risk was sustained with long-term use and declined gradually after stopping ICS use, disappearing after 6 months (RR 1.08; 95% CI 0.99 to 1.17). The rate of serious pneumonia was higher with fluticasone (RR 2.01; 95% CI 1.93 to 2.10), increasing with the daily dose, but was much lower with budesonide (RR 1.17; 95% CI 1.09 to 1.26).

Conclusions

ICS use by patients with COPD increases the risk of serious pneumonia. The risk is particularly elevated and dose related with fluticasone. While residual confounding cannot be ruled out, the results are consistent with those from recent randomised trials.

Induction of regulator of G-protein signaling 2 expression by long-acting β2-adrenoceptor agonists and glucocorticoids in human airway epithelial cells

In asthma and chronic obstructive pulmonary disease (COPD) multiple mediators act on Gαq-linked G-protein-coupled receptors (GPCRs) to cause bronchoconstriction. However, acting on the airway epithelium, such mediators may also elicit inflammatory responses. In human bronchial epithelial BEAS-2B cells (bronchial epithelium + adenovirus 12-SV40 hybrid), regulator of G-protein signaling (RGS) 2 mRNA and protein were synergistically induced in response to combinations of long-acting β2-adrenoceptor agonist (LABA) (salmeterol, formoterol) plus glucocorticoid (dexamethasone, fluticasone propionate, budesonide). Equivalent responses occurred in primary human bronchial epithelial cells. Concentrations of glucocorticoid plus LABA required to induce RGS2 expression in BEAS-2B cells were consistent with the levels achieved therapeutically in the lungs. As RGS2 is a GTPase-activating protein that switches off Gαq, intracellular free calcium ([Ca(2+)]i) flux was used as a surrogate of responses induced by histamine, methacholine, and the thromboxane receptor agonist U46619 [(Z)-7-[(1S,4R,5R,6S)-5-[(E,3S)-3-hydroxyoct-1-enyl]-3-oxabicyclo[2.2.1]heptan-6-yl]hept-5-enoic acid]. This was significantly attenuated by salmeterol plus dexamethasone pretreatment, or RGS2 overexpression, and the protective effect of salmeterol plus dexamethasone was abolished by RGS2 RNA silencing. Although methacholine and U46619 induced interleukin-8 (IL-8) release and this was inhibited by RGS2 overexpression, the repression of U46619-induced IL-8 release by salmeterol plus dexamethasone was unaffected by RGS2 knockdown. Given a role for Gαq-mediated pathways in inducing IL-8 release, we propose that RGS2 acts redundantly with other effector processes to repress IL-8 expression. Thus, RGS2 expression is a novel effector mechanism in the airway epithelium that is induced by glucocorticoid/LABA combinations. This could contribute to the efficacy of glucocorticoid/LABA combinations in asthma and COPD.

Fluticasone/formoterol dry powder versus budesonide/formoterol in adults and adolescents with uncontrolled or partly controlled asthma

This 12-week study compared the efficacy and safety of a fixed combination of fluticasone propionate plus formoterol (FL/F) 250/12 μg b.i.d. administered via a dry powder inhaler (DPI) (Libbs Farmacêutica, Brazil) to a combination of budesonide plus formoterol (BD/F) 400/12 μg b.i.d. After a 2-week run-in period (in which all patients were treated exclusively with budesonide plus formoterol), patients aged 12-65 years of age (N = 196) with uncontrolled asthma were randomized into an actively-controlled, open-labeled, parallel-group, multicentre, phase III study. The primary objective was to demonstrate non-inferiority, measured by morning peak expiratory flow (mPEF). The non-inferiority was demonstrated. A statistically significant improvement from baseline was observed in both groups in terms of lung function, asthma control, and the use of rescue medication. FL/F demonstrated a statistical superiority to BD/F in terms of lung function (FEV(1)) (p = 0.01) and for asthma control (p = 0.02). Non-significant between-group differences were observed with regards to exacerbation rates and adverse events. In uncontrolled or partly controlled asthma patients, the use of a combination of fluticasone propionate plus formoterol via DPI for 12-weeks was non-inferior and showed improvements in FEV(1) and asthma control when compared to a combination of budesonide plus formoterol. (

CLINICAL TRIAL NUMBER

ISRCTN60408425).

Multidrug resistance-associated protein 1 and lung function decline with or without long-term corticosteroids treatment in COPD

Multidrug resistance-associated protein-1 (MRP1) reduces the oxidative stress generated by smoking, a risk factor for Chronic Obstructive Pulmonary Disease (COPD). We previously showed that MRP1 variants are associated with the level and decline of annual forced expiratory volume in one second (FEV(1)) in the general population. Moreover, we showed that MRP1 variants are also associated with FEV(1) level and inflammatory markers in COPD patients.We investigate in the current study the association of MRP1 protein expression in bronchial biopsies with FEV(1) decline in COPD patients using placebo, or inhaled corticosteroids (ICS) with or without long-acting β2-agonists. Additionally we investigate the association of MRP1 variants with FEV(1) decline. MRP1 variants (rs212093, rs4148382, rs504348, rs4781699, rs35621) were genotyped in 110 COPD patients. Associations of MRP1 variants and MRP1 protein expression in bronchial biopsies (obtained at baseline, 6 and 30 months) with FEV(1) decline were analyzed using linear mixed-effect models. During 30-month ICS treatment, subjects with a moderate staining for MRP1 had less FEV(1) decline than those with a weak staining. In subjects stopping ICS after 6 months followed by 24-month placebo, moderate staining for MRP1 was associated with faster FEV(1) decline than in those with a weak staining. None of the variants was associated with FEV(1) decline. Our unique study suggests a role of MRP1 protein expression in bronchial biopsies in FEV(1) decline occurring selectively in COPD patients with long-term (30-month) ICS therapy.

Nongenomic effects of fluticasone propionate and budesonide on human airway anion secretion

This study investigated the physiological effects of inhaled corticosteroids, which are used widely to treat asthma. The application of fluticasone propionate (FP, 100 μM) induced sustained increases in the short-circuit current (I(SC)) in human airway Calu-3 epithelial cells. The FP-induced I(SC) was prevented by the presence of H89 (10 μM, a protein kinase A inhibitor) and SQ22536 (100 μM, an adenylate cyclase inhibitor). The FP-induced responses involved bumetanide (a Na(+)-K(+)-2Cl(-) cotransporter inhibitor)-sensitive and 4,4'-dinitrostilbene-2,2'-disulfonic acid (an inhibitor of HCO(3)(-)-dependent anion transporters)-sensitive components, both of which reflect basolateral anion transport. Further, FP augmented apical membrane Cl(-) current (I(Cl)), reflecting cystic fibrosis transmembrane conductance regulator (CFTR)-mediated conductance, in the nystatin-permeabilized monolayer. In I(SC) and I(Cl) responses, FP failed to enhance the responses to forskolin (10 μM, an adenylate cyclase activator). Nevertheless, we found that FP synergistically increased cytosolic cAMP concentrations in combination with forskolin. All these effects of FP were reproduced with the use of budesonide. Collectively, inhaled corticosteroids such as FP and budesonide stimulate CFTR-mediated anion transport through adenylate cyclase-mediated mechanisms in a nongenomic fashion, thus sharing elements of a common pathway with forskolin. However, the corticosteroids cooperate with forskolin for synergistic cAMP production, suggesting that the corticosteroids and forskolin do not compete with each other to exert their effects on adenylate cyclase. Considering that such synergism was also observed in the FP/salmeterol combination, these nongenomic aspects may play therapeutic roles in mucus congestive airway diseases, in addition to genomic aspects that are generally recognized.

Detection of fluticasone propionate in horse plasma and urine following inhaled administration

Fluticasone propionate (FP) is an anti-inflammatory agent with topical and inhaled applications commonly used in the treatment of asthma in steroid-dependent individuals. The drug is used in racehorses to treat Inflammatory Airway Disease; this work was performed in order to advise on its use and detect potential misuse close to racing. Methods were developed for the extraction and analysis of FP from horse plasma and a carboxylic acid metabolite (FP-17βCOOH) from horse urine. The methods utilize ultra high performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS) in order to detect the extremely low concentrations of analyte present in both matrices. The developed methods were used to analyse plasma and urine samples collected following inhaled administration of FP to six thoroughbred horses. FP was detected in plasma for a minimum of 72 h post-administration and FP-17βCOOH was detected in urine for approximately 18 h post-administration. The results show that it is possible to detect FP in the horse following inhaled administration.

Lung function changes in asthmatic children treated with HFA-BDP

STUDY OBJECTIVES

Asthma guidelines suggest that normal or near normal lung function should be one of the goals for good asthma control. Therefore, children with chronic persistent asthma and reduced peripheral airway function were assessed after the replacement of conventional inhaled corticosteroids (ICS) with an extrafine aerosol formulation, hydrofluoroalkane-134a beclomethoasone diproprionate (HFA-BDP).

DESIGN AND SETTING

Lung function and clinical details were studied in children with moderate persistent asthma who regularly attended the pediatric pulmonary outpatient clinic at Kosair Children's Hospital, Louisville, Kentucky, USA.

SUBJECTS

A total of 20 children, 7 girls and 13 boys, with stable asthma but reduced forced expiratory flows between 25% and 75% of vital capacity (FEF(25-75) ) were included in the study.

INTERVENTION

After the initial assessment, each subject was switched from conventional ICS to HFA-BDP. All other medications remained the same. Reassessment of lung function and clinical status was performed at least 3 weeks after the intervention.

RESULTS

FEF(25-75) increased from a mean of 50.75% to 68.85% predicted (P < 0.001). Forced expiratory volume in 1 sec (FEV(1)) also increased significantly from 84.6% to 93.8% predicted (P = 0.001). No changes asthma symptoms were observed.

CONCLUSION

Compared to conventional ICS, the use of HFA-BDP in asthmatic children significantly improves airflow in both the large and the peripheral airways without loss of asthma control.

Targeting small airways, a step further in asthma management

INTRODUCTION

During the last decade, small airway (SA) involvement in asthma and Chronic Obstructive Pulmonary Disease (COPD) have reached increasing attention. Originally referred to as the 'silent zone', SA may not be that silent after all. Important clinical correlates are asthma exacerbations and airways remodelling, exercise asthma and nocturnal asthma. Thus, to control pathology in the SA has become a desirable goal in asthma management.

OBJECTIVES

The scope of this review is to give a brief overview of the current status on SA in asthma, how to monitor and to diagnose SA inflammation and finally highlight some important treatment strategies.

RESULTS/CONCLUSION

New tools have been developed to monitor SA function; these implies the use of imaging techniques and respiratory physiology, targeting SA function. Fractional exhaled nitric oxide and the combined use of hyperresponsiveness testing with impulsoscillometry is another option. The introduction of ultrafine aerosols has provided new tools for to treat SA inflammation. The challenge for the future will be to define the optimal particle size and device for maximal deposition in entire lung, including the small airways. Moreover, we also need strategies for increasing the therapeutic ratio, i.e. increasing lung deposition without increasing systemic side effects. Another challenge is to design and to perform clinical trials, targeting effects in SA, proving the clinical importance of SA treatment in a large number of patients. The latter also imply education of our medical authorities, communicating that asthma is more than a beta-2 agonist responsive central airway disorder of the lungs.

TGFβ-induced matrix production by bronchial fibroblasts in asthma: budesonide and formoterol effects

To investigate the mechanisms of enhanced airway deposition of subepithelial collagen in asthma and its sensitivity to drug therapy with combination of an inhaled glucocorticosteroid (GC) and a long-acting β(2)-agonist (LABA), a cell model system involving bronchial fibroblasts derived from biopsies from patients with stable mild-to-moderate asthma has been used. To mimic unstable conditions and severe asthma, fibroblasts were stimulated ex vivo with TGFβ1. Primary fibroblasts established from central bronchial biopsies from 8 asthmatic patients were incubated for 24 h with 0.4% serum or TGFβ1 (10 ng/ml) with/without the GC budesonide (BUD; 10 nM) and/or the LABA formoterol (FORM; 0.1 nM). Procollagen peptide I (PICP), metalloproteinase (MMP)-1 and tissue inhibitor of MMPs (TIMP-1) were determined in culture media using ELISA while the activity of MMP-2, -3, -9 by zymography. Metabolically labeled proteoglycans, biglycan and decorin, associated with collagen fibrillation/deposition, were separated using chromatography and SDS-PAGE. The levels of PICP and biglycan were increased 2-fold by TGFβ1 (p < 0.05). The BUD and FORM combination reduced the PICP increase by 58% (p < 0.01) and the biglycan by 36% (p < 0.05) while each drug alone had no effect. Decorin levels were reduced by TGFβ1 in fibroblasts of most patients; BUD alone and BUD and FORM completely counteracted this decrease. MMPs and TIMP-1 were not affected by TGFβ1 or the drugs. These results suggest that BUD and FORM combination therapy, without affecting metalloproteolytic balance, has a potential to counteract enhanced collagen production by bronchial fibroblasts in asthma and to normalize the production of small proteoglycans which may affect collagen fibrillation and deposition.

Non-invasive systemic drug delivery: developability considerations for alternate routes of administration

Over the past few decades alternate routes of administration have gained significant momentum and attention, to complement approved drug products, or enable those that cannot be delivered by the oral or parenteral route. Intranasal, buccal/sublingual, pulmonary, and transdermal routes being the most promising non-invasive systemic delivery options. Considering alternate routes of administration early in the development process may be useful to enable new molecular entities (NME) that have deficiencies (extensive first-pass metabolism, unfavorable physicochemical properties, gastro-intestinal adverse effects) or suboptimal pharmacokinetic profiles that are identified in preclinical studies. This review article describes the various delivery considerations and extraneous factors in developing a strategy to pursue an alternate route of administration for systemic delivery. The various delivery route options are outlined with their pros and cons; key criteria and physicochemical attributes that would make a drug a suitable candidate are discussed; approaches to assess delivery feasibility, toxicity at the site of delivery, and overall developability potential are described; and lastly, product trends and their disease implications are highlighted to underscore treatment precedence that help to build scientific rationale for the pursuit of an alternate route of administration.

Modulation by flunisolide of tumor necrosis factor-alpha-induced stimulation of airway epithelial cell activities related to eosinophil inflammation

BACKGROUND

Tumor necrosis factor (TNF)-alpha, a proinflammatory cytokine involved in the pathogenesis of asthma, displays multiple functions on a variety of cells, including bronchial epithelial cells (BECs).

OBJECTIVE

To characterize in vitro changes induced by TNF-alpha on the function of BECs that may be related to eosinophilic inflammation and to evaluate their modulation by an inhaled corticosteroid, flunisolide.

METHODS

A normal human bronchial epithelial cell line (BEAS-2B) was incubated with TNF-alpha (10 ng/ml) to evaluate (a) intercellular adhesion molecule (ICAM)-1 expression and granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin (IL)-5 release by BEAS-2B; (b) eosinophil adhesion to BEAS-2B; and (c) the modulation of these activities by flunisolide (0.1 to 10 microM).

RESULTS

Stimulation of BEAS-2 with TNF-alpha generated an increase in ICAM-1 expression (p = .0012), in GM-CSF and IL-5 release (p < .01), and in eosinophil adhesion to BEAS-2B, but this latter effect did not reach statistical significance. Flunisolide at all the tested concentrations effectively inhibited ICAM-1 expression and GM-CSF and IL-5 release (p < .05). The percent inhibition induced by the highest flunisolide concentration (10 muM) for the various BEAS-2B functions was 30%, 60%, and 70%, respectively. The effect of flunisolide appeared to be related to an inhibition of "TNF-alpha-induced" ICAM-1 expression and cytokine release with little or no involvement of the "constitutive" expression and release.

CONCLUSION

An increase in ICAM-1 expression in BECs was found to be induced by TNF-alpha and associated with enhancement of the constitutive secretion of GM-CSF and IL-5, cytokines related to eosinophilic inflammation. The ability of flunisolide to modulate these BECs activities appears to be mostly related to the inhibition of the "TNF-alpha-induced" responses.

New insights into the pathophysiology of the small airways in asthma

Asthma is a lung disease characterized by inflammation and remodeling of the airways, which leads to airflow obstruction and symptoms of wheeze, chest tightness, cough and dyspnea. It is now widely accepted that airway inflammation and remodeling occur not only in the central airways but also in the small airways and even in the lung parenchyma. Inflammation of the distal lung can be observed even in mild asthmatics with normal or noncompromised lung function. Moreover, the small airways and the lung parenchyma can produce many Th2 cytokines and chemokines involved in initiation and perpetuation of the inflammatory process. In addition, the distal parts of the lung have been recognized as a predominant site of airflow obstruction in asthmatics. In fact, the inflammation at this distal site has been described as more severe when compared to the large airway inflammation, and evidence of remodeling in the lung periphery is emerging. Recognition of asthma as a disease of the entire respiratory tract has an important clinical significance, highlighting the need to also consider the distal lung as a target in any therapeutic strategy for effective treatment of this disease.

Effect of formoterol and budesonide on chemokine release, chemokine receptor expression and chemotaxis in human neutrophils

Severe persistent asthma and chronic obstructive pulmonary disease (COPD) are associated with neutrophil influx into the airways. It is not clear whether neutrophil chemotaxis is influenced by beta(2)-agonists and glucocorticoids, drugs commonly used in treatment of asthma and COPD. The effect of a long-acting beta(2)-agonist (formoterol), and a glucocorticosteroid (budesonide) on chemokine/cytokine release (CXCL8, CXCL1, IL-6), regulation of chemokine receptors (CXCR1, CXCR2), and migration were assessed in neutrophils from 10 non-allergic, healthy donors. Formoterol enhanced and budesonide inhibited IL-6, CXCL8 and CXCL1 release from LPS-stimulated neutrophils. Formoterol up-regulated both CXCR1 and CXCR2 expression, whereas budesonide up-regulated the expression of CXCR2 only. Despite the effects on chemokine release and drug-induced up-regulation of CXCR1 and CXCR2, no influence on neutrophil chemotaxis could be demonstrated. We conclude that a beta(2)-agonist and a glucocorticoid, commonly used in the treatment of obstructive lung diseases, influence chemokine release and receptor sensitivity but the functional consequences of these findings remain unclear.

Effect of an inhaled glucocorticoid on endothelial function in healthy smokers

Cigarette smoking is associated with attenuated endothelium-dependent vasodilation (endothelial dysfunction) in the systemic circulation, including the airway circulation. We wished to determine whether an inhaled corticosteroid could restore endothelial function in the airway of lung-healthy current smokers, ex-smokers, and nonsmokers. We measured baseline airway blood flow (Qaw) and Qaw reactivity to inhaled albuterol as an index of endothelium-dependent vasodilation and to sublingual nitroglycerin as an index of endothelium-independent vasodilation in lung-healthy current smokers, ex-smokers, and nonsmokers. Current smokers were then treated with inhaled fluticasone for 3 wk, and all measurements were repeated after fluticasone treatment and after a subsequent 3-wk fluticasone washout period. Baseline mean Qaw and endothelium-independent Qaw reactivity were similar in the three groups. Mean endothelium-dependent Qaw reactivity was 49.5% in nonsmokers, 42.7% in ex-smokers, and 10.8% in current smokers (P < 0.05 vs. nonsmokers). In current smokers, mean baseline Qaw was unchanged after fluticasone treatment, but endothelium-dependent Qaw reactivity significantly increased to 34.9%. Qaw reactivity was again blunted after fluticasone washout. Endothelial dysfunction, as assessed by vascular reactivity, can be corrected with an inhaled corticosteroid in the airway of lung-healthy current smokers. This proof of concept can serve as the basis for future clinical investigations on the effect of glucocorticoids on endothelial function in smokers.

Evidence of the in vivo esterification of budesonide in human airways

AIMS

Budesonide, unlike fluticasone propionate, undergoes fatty acid esterification in the lungs, and there is a need to characterize fully the distribution and fate of the two drugs after inhalation in humans.

METHODS

This open-label, randomized study was performed in adults undergoing whole lung or lobar resection resulting from lung cancer. Patients were given single 1000-mug doses of both budesonide and fluticasone propionate via dry powder inhalers before surgery. Tissue samples from peripheral and central lung, an ex vivo bronchial brush sample and intercostal muscle, together with plasma samples, were taken during surgery and analysed by liquid chromatography plus tandem mass spectrometry.

RESULTS

Lung tissue samples were obtained from 22 patients at surgery, 1-43 h after drug dosing. Budesonide was detectable from earliest sampling in central and peripheral lung tissue up to 10 h (in six of 22 samples), fluticasone propionate up to 22 h after inhalation (in 16 of 22 samples), and budesonide oleate up to 43 h after inhalation (in 21 of 22 samples). Budesonide, but not fluticasone propionate, was detected in intercostal muscle for up to 10 h after inhalation. Bronchial brush samples showed the presence of fluticasone propionate for up to 18 h, suggesting the presence of undissolved drug powder particles in the airway lumen.

CONCLUSION

Sustained retention of esterified budesonide in the lungs supports the prolonged duration of action of budesonide and suitability for once-daily administration.

Epithelial expression of TLR4 is modulated in COPD and by steroids, salmeterol and cigarette smoke

The toll-like receptors (TLRs) are a key component of host defense in the respiratory epithelium. Cigarette smoking is associated with increased susceptibility to infection, while COPD is characterised by bacterial colonisation and infective exacerbations. We found reduced TLR4 gene expression in the nasal epithelium of smokers compared with non-smoking controls, while TLR2 expression was unchanged. Severe COPD was associated with reduced TLR4 expression compared to less severe disease, with good correlation between nasal and tracheal expression. We went on to examine the effect of potential modulators of TLR4 expression in respiratory epithelium pertinent to airways disease. Using an airway epithelial cell line, we found a dose-dependent downregulation in TLR4 mRNA and protein expression by stimulation with cigarette smoke extracts. Treatment with the corticosteroids fluticasone and dexamethasone resulted in a dose-dependent reduction in TLR4 mRNA and protein. The functional significance of this effect was demonstrated by impaired IL-8 and HBD2 induction in response to LPS. Stimulation with salmeterol (10-6 M) caused upregulation of TLR4 membrane protein presentation with no upregulation of mRNA, suggesting a post-translational effect. The effect of dexamethasone and salmeterol in combination was additive, with downregulation of TLR4 gene expression, and no change in membrane receptor expression. Modulation of TLR4 in respiratory epithelium may have important implications for airway inflammation and infection in response to inhaled pathogens.