Transcriptional potencies of inhaled glucocorticoids

Development and biopharmaceutical evaluation of aqueous micelle based corticosteroid formulations for topical treatment of oral lichen planus

The dearth of approved products to treat oral lichen planus (OLP) compels off-label use of dermatological corticosteroid formulations not optimized for indications in the oral cavity. The aims of this study were to develop aqueous micelle based formulations of triamcinolone acetonide (TA) and fluocinonide (FLU), using D-tocopheryl polyethylene glycol succinate, and to investigate corticosteroid delivery to the epithelium-lamina propria junction region - the anatomical target for OLP treatment - in comparison to that from marketed products. Total mucosal deposition of TA after application of Kenacort® A Orabase® (0.1 % TA) and micellar hydrogel (0.1 %) was 242.1 ± 68.5 and 5936.7 ± 1269.6 ng/cm2, respectively. For FLU, deposition after application of Novoter (0.05 % FLU) and micellar hydrogel (0.05 %) was 617.1 ± 126.5 and 2580.0 ± 285.5 ng/cm2, respectively. A buccal biodistribution study showed that application of micelle hydrogels under occlusion for 30 min delivered 117.0 ± 15.6 ng/cm2 and 225.6 ± 36.7 ng/cm2, of TA and FLU, respectively, to the epithelium-lamina propria junction region. In contrast, the amounts deposited after applying Kenacort® A Orabase® and Novoter, were < LOQ. The results demonstrated that TPGS-based micelles improved mucosal bioavailability of TA and FLU in the epithelium-lamina propria junction region and might serve to improve topical OLP therapy.

The effects of inhaled corticosteroids on healthy airways

BACKGROUND

The effects of inhaled corticosteroids (ICS) on healthy airways are poorly defined.

OBJECTIVES

To delineate the effects of ICS on gene expression in healthy airways, without confounding caused by changes in disease-related genes and disease-related alterations in ICS responsiveness.

METHODS

Randomized open-label bronchoscopy study of high-dose ICS therapy in 30 healthy adult volunteers randomized 2:1 to (i) fluticasone propionate 500 mcg bd daily or (ii) no treatment, for 4 weeks. Laboratory staff were blinded to allocation. Biopsies and brushings were analysed by immunohistochemistry, bulk RNA sequencing, DNA methylation array and metagenomics.

RESULTS

ICS induced small between-group differences in blood and lamina propria eosinophil numbers, but not in other immunopathological features, blood neutrophils, FeNO, FEV1, microbiome or DNA methylation. ICS treatment upregulated 72 genes in brushings and 53 genes in biopsies, and downregulated 82 genes in brushings and 416 genes in biopsies. The most downregulated genes in both tissues were canonical markers of type-2 inflammation (FCER1A, CPA3, IL33, CLEC10A, SERPINB10 and CCR5), T cell-mediated adaptive immunity (TARP, TRBC1, TRBC2, PTPN22, TRAC, CD2, CD8A, HLA-DQB2, CD96, PTPN7), B-cell immunity (CD20, immunoglobulin heavy and light chains) and innate immunity, including CD48, Hobit, RANTES, Langerin and GFI1. An IL-17-dependent gene signature was not upregulated by ICS.

CONCLUSIONS

In healthy airways, 4-week ICS exposure reduces gene expression related to both innate and adaptive immunity, and reduces markers of type-2 inflammation. This implies that homeostasis in health involves tonic type-2 signalling in the airway mucosa, which is exquisitely sensitive to ICS.

Asthma and COVID-19: Emphasis on Adequate Asthma Control

Asthmatics are at an increased risk of developing exacerbations after being infected by respiratory viruses such as influenza virus, parainfluenza virus, and human and severe acute respiratory syndrome coronaviruses (SARS-CoV). Asthma, especially when poorly controlled, is an independent risk factor for developing pneumonia. A subset of asthmatics can have significant defects in their innate, humoral, and cell-mediated immunity arms, which may explain the increased susceptibility to infections. Adequate asthma control is associated with a significant decrease in episodes of exacerbation. Because of their wide availability and potency to promote adequate asthma control, glucocorticoids, especially inhaled ones, are the cornerstone of asthma management. The current COVID-19 pandemic affects millions of people worldwide and possesses mortality several times that of seasonal influenza; therefore, it is necessary to revisit this subject. The pathogenesis of SARS-CoV-2, the virus that causes COVID-19, can potentiate the development of acute asthmatic exacerbation with the potential to worsen the state of chronic airway inflammation. The relationship is evident from several studies that show asthmatics experiencing a more adverse clinical course of SARS-CoV-2 infection than nonasthmatics. Recent studies show that dexamethasone, a potent glucocorticoid, and other inhaled corticosteroids significantly reduce morbidity and mortality among hospitalized COVID-19 patients. Hence, while we are waiting for more studies with higher level of evidence that further narrate the association between COVID-19 and asthma, we advise clinicians to try to achieve adequate disease control in asthmatics as it may reduce incidences and severity of exacerbations especially from SARS-CoV-2 infection.

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.

Beneficial Immunomodulatory Effects of Fluticasone Propionate in Chlamydia pneumoniae-Infected Mice

The associations between inhaled corticosteroid (ICS) use and pulmonary infections remains controversial. Chlamydia pneumoniae (C. pneumoniae) accounts for asthma exacerbations; however, there are no data regarding ICS effects on C. pneumoniae infections. Thus, we investigated whether fluticasone propionate (FP) or budesonide (BUD) could affect C. pneumoniae infection in vitro and in vivo, focusing on the possible mechanisms that lead to potential anti-chlamydial outcomes. We performed direct qPCR to detect C. pneumoniae growth in infected, FP-treated, and BUD-treated A549 cells. Furthermore, FP or BUD was administered by inhalation to C. pneumoniae-infected mice. The recoverable C. pneumoniae was determined by indirect immunofluorescence. Expression levels of interferon (IFN)-γ and IFN-γ inducible chemokines were assessed by qPCR. We measured the protein concentrations of IFN-γ and of other cytokines that potentially participate in the anti-chlamydial response by ELISA. We found that FP treatment suppressed Chlamydia growth in A549 cells and in mice. Higher levels of IFN-γ gene expression were observed in FP-treated mice compared to the untreated and BUD-treated mice (p < 0.0001). IFN-γ and anti-chlamydial protein MIG/CXCL9 values were significantly higher after FP inhalation. Collectively, FP, but not BUD, suppressed C. pneumoniae growth in vitro and in vivo, which was likely due to the enhanced IFN-γ related responses.

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.

The Effects of Steroids on Survival of Mouse and Human Tympanic Membrane Fibroblasts

OBJECTIVE

Tympanic membrane (TM) fibroblast cytotoxicity of quinolone ear drops is enhanced by dexamethasone and fluocinolone. Hydrocortisone has not been evaluated. We aimed to assess the effects of these 3 steroids on mouse and human TM fibroblast survival.

STUDY DESIGN

In vitro.

SETTING

Academic laboratory.

SUBJECTS AND METHODS

Mouse and human TM fibroblasts were exposed to hydrocortisone, dexamethasone, or fluocinolone at concentrations in commercial ear drops (1%, 0.1%, or 0.025%, respectively) and at steroid potency equivalents (1%, 0.033%, or 0.0033%, respectively), or dilute ethanol (control), twice within 24 hours or 4 times within 48 hours for 2 hours each time. Cells were observed with phase-contrast microscopy until the cytotoxicity assay was performed.

RESULTS

Mouse and human TM fibroblasts treated with any of the steroids had lower survival after 24 and 48 hours compared to control (all P < .0001). After 24 hours, viability of mouse fibroblasts treated with the steroids was not different (P > .05), while treatment with hydrocortisone decreased human TM fibroblast viability (P < .0001). After 48 hours, at concentrations found in ear drops and at equivalent steroid potency, dexamethasone and fluocinolone had similar survival in mouse and human fibroblasts (all P > .05), but hydrocortisone had lower survival in both mouse (P = .02 and P < .0001) and human (P < .0001) fibroblasts. Phase-contrast images mirrored the cytotoxicity findings.

CONCLUSION

Steroids found in commercial ear drops reduce survival of mouse and human TM fibroblasts. Hydrocortisone appears to be more cytotoxic than the more potent steroids, dexamethasone and fluocinolone. These findings should be considered when assessing clinical outcomes of ototopical preparations.

Controlled non-invasive iontophoretic delivery of triamcinolone acetonide amino acid ester prodrugs into the posterior segment of the eye

This study investigated short duration transscleral iontophoretic delivery of four triamcinolone acetonide (TA) amino acid ester prodrugs (TA-AA) (alanine, Ala; arginine, Arg; isoleucine, Ile and lysine, Lys) using whole porcine eyes globes in vitro. Post-iontophoretic biodistribution of TA was quantified by UHPLC-MS/MS in the different ocular compartments (cornea, aqueous humor, sclera, ciliary body, choroid and retinal pigmented epithelium (RPE), neural retina and vitreous humor). Transscleral iontophoresis (3 mA/cm² for 10 min) increased total drug delivery of the TA-AA prodrugs by 14-30-fold as compared to passive diffusion. The TA-AA prodrugs had distinct biodistribution profiles - the penetration depth achieved was dependent on their physicochemical properties (e.g. lipophilicity for TA-Ile) and susceptibility to hydrolysis (e.g. TA-Arg). Intraocular drug distribution was also influenced by prodrug binding to melanin (TA-Lys). Interestingly, under conditions of equivalent charge (6 mA/cm² for 5 min vs. 1.5 mA/cm² for 20 min, i.e. 1.44 C respectively) the longer duration (20 min) at lower current density resulted in ∼6 times more TA delivery into the vitreous humor. Overall, the study provided further evidence of the potential of transscleral iontophoresis for the non-invasive treatment of posterior segment inflammatory diseases.

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.

Targeted intracorneal delivery-Biodistribution of triamcinolone acetonide following topical iontophoresis of cationic amino acid ester prodrugs

The aim was to investigate intracorneal iontophoresis of biolabile triamcinolone acetonide (TA) amino acid ester prodrugs (TA-AA). Arginine and lysine esters of TA (TA-Arg and TA-Lys, respectively) were synthesized and characterized; quantification was performed by HPLC-UV and UHPLC-MS/MS. The aqueous solubility of the prodrugs (at pH 5.5) was ∼1000-fold greater than TA. Anodal iontophoresis (10min at 3mA/cm²) of TA-AA was investigated using isolated porcine cornea. Although no statistically significant difference was observed in total intracorneal delivery of TA (468.25±59.70 and 540.85±79.16nmol_TA/cm², for TA-Arg and TA-Lys, respectively), the different susceptibilities of the prodrugs to hydrolysis influenced intracorneal biodistribution. Quantification of TA in twenty-five 40μm thick corneal lamellae revealed significantly deeper penetration of TA following TA-Lys iontophoresis. Its superior resistance to hydrolysis enabled sustained electromigration into the deeper cornea suggesting judicious prodrug selection might enable targeted regioselective drug delivery. The intracorneal biodistribution following anodal iontophoresis of TA-Arg (2.3mM; 10min, 3mA/cm²) was visualized by full field optical coherence tomography providing qualitative confirmation of the extensive intracorneal penetration of TA. Short duration iontophoresis of TA-AA prodrugs may improve deep corneal bioavailability and efficacy in vivo, constituting a "single-shot" treatment option for corneal allograft rejection.

Pharmacokinetics of Budesonide Administered with Surfactant in Premature Lambs: Implications for Neonatal Clinical Trials

Bronchopulmonary dysplasia (BPD) is a chronic lung disease of premature human infants, which may persist through adulthood. Airway inflammation has been firmly established in the pathogenesis of BPD. Previous studies to reduce airway inflammation with high-dose dexamethasone demonstrated adverse neurological outcomes, despite lower incidences of BPD. Instillation of budesonide and surfactant can facilitate early extubation and reduce the incidence of BPD and death among very low birth weight infants. However, the pharmacokinetics of budesonide and its distribution into the lung and brain are unknown. Therefore, 5 premature lambs were administered 0.25 mg/kg budesonide, with surfactant as the vehicle. Plasma and tissue samples were taken from the lambs for measurement of budesonide, 16α- hydroxy prednisolone, and budesonide palmitate using LC/MS/MS. Peak plasma budesonide concentrations were inversely correlated with the oxygenation index (correlation coefficient of -0.75). plasma budesonide concentrations were extremely low (~10% of expected) for two lambs that had high oxygenation indices and were excluded from further analyses. For the remaining 5 premature lambs, a non-compartmental analysis demonstrated an AUCinf of 148.77 ± 28.16 h*μg/L, half-life of 4.76 ± 1.79 h, and Cmax of 46.17 ± 17.71 µg/L. Using population pharmacokinetic methods, a onecompartment model with exponential residual error and first-order absorption adequately described the data. The apparent clearance and apparent volume of distribution of budesonide were estimated at 6.29 L/h (1.99 L/h/kg) and 29.1 L (9.2 L/kg), respectively. Budesonide and budesonide palmitate, but not 16α-hydroxy prednisolone, were detected in lung tissue. In this study, budesonide and its metabolites were not detected in the brain, which suggests that intratracheal instillation suggests that after local pulmonary deposition, there is no evidence of budesonide accumulation in the central nervous system. Overall, these results show that peak plasma budesonide concentrations are inversely correlated with the oxygenation index and that lung-specific delivery of budesonide avoids accumulation of budesonide in the brain.

Molecular and cellular mechanisms underlying the therapeutic effects of budesonide in asthma

Inhaled glucocorticoids are the mainstay of asthma treatment. Indeed, such therapeutic agents effectively interfere with many pathogenic circuits underpinning asthma. Among these drugs, during the last decades budesonide has been probably the most used molecule in both experimental studies and clinical practice. Therefore, a large body of evidence clearly shows that budesonide, either alone or in combination with long-acting bronchodilators, provides a successful control of asthma in many patients ranging throughout the overall spectrum of disease severity. These excellent therapeutic properties of budesonide basically depend on its molecular mechanisms of action, capable of inhibiting within the airways the activity of multiple immune-inflammatory and structural cells involved in asthma pathobiology.

[A new fixed dose combination of fluticasone and formoterol in a pressurised metered-dose inhaler for the treatment of asthma]

The combination of an inhaled corticosteroid and a long acting beta-2 agonist is indicated for the regular treatment of persistent moderate-to-severe asthmatics whose asthma is not controlled by inhaled corticosteroids and the occasional use of a short acting beta-2 agonist. The aim of this review is to give an overview of the rationale of combining formoterol and fluticasone and to analyze the clinical data concerning a new fixed combination of fluticasone and formoterol in a pressurised metered-dose inhaler with a dose counter (Flutiform(®)) that was approved for the treatment of asthma in France in 2013. The clinical studies provide evidence that combined fluticasone/formoterol is more efficacious than fluticasone or formoterol given alone, and provides similar improvements in lung function to fluticasone (Flixotide(®)) and formoterol (Foradil(®)) administered concurrently. The combination of fluticasone/formoterol gave a more rapid bronchodilatation than the combination fluticasone/salmeterol. As a whole, the combination of fluticasone/formoterol had similar efficacy and tolerability profiles to the combinations of either budesonide/formoterol or fluticasone/salmeterol.

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).

MAPK/NF-κB-dependent upregulation of kinin receptors mediates airway hyperreactivity: a new perspective for the treatment

Airway hyperreactivity (AHR) is a major feature of asthmatic and inflammatory airways. Cigarette smoke exposure, and bacterial and viral infections are well-known environmental risk factors for AHR, but knowledge about the underlying molecular mechanisms on how these risk factors lead to the development of AHR is limited. Activation of intracellular mitogen-activated protein kinase (MAPK)/nuclear factor-kappa B (NF-κB) and their related signal pathways including protein kinase C (PKC), phosphoinositide 3-kinase (PI3K) and protein kinase A (PKA) signaling pathways may result in airway kinin receptor upregulation, which is suggested to play an important role in the development of AHR. Environmental risk factors trigger the production of pro-inflammatory mediators such as tumor necrosis factor-α (TNF-α) and interleukins (ILs) that activate intracellular MAPK- and NF-κB-dependent inflammatory pathways, which subsequently lead to AHR via kinin receptor upregulation. Blockage of intracellular MAPK/NF-κB signaling prevents kinin B₁ and B₂ receptor expression in the airways, resulting in a decrease in the response to bradykinin (kinin B₂ receptor agonist) and des-Arg⁹-bradykinin (kinin B₁ receptor agonist). This suggests that MAPK- and NF-κB-dependent kinin receptor upregulation can provide a novel option for treatment of AHR in asthmatic as well as in other inflammatory airway diseases.

Novel low molecular weight lignins as potential anti-emphysema agents: In vitro triple inhibitory activity against elastase, oxidation and inflammation

No molecule has been found to be effective against emphysema to date primarily because of its complex pathogenesis that involves elastolysis, oxidation and inflammation. We here describe novel unsulfated or sulfated low molecular weight lignins (LMWLs) chemo-enzymatically prepared from 4-hydroxycinnamic acids monomers, as the first potent triple-action inhibitors of neutrophil elastase, oxidation and inflammation. The inhibitory potencies of three different cinnamic acid-based LMWLs were determined in vitro using chromogenic substrate hydrolysis assays, radical scavenging and lung cellular oxidative biomarker reduced glutathione (rGSH) assays, and lung cellular inflammatory biomarker NFκB and IL-8 assays, respectively. Each LWML uniquely displayed triple-action inhibition, among which CDSO3, a sulfated caffeic acid-based LMWL, was most potent. The half-maximal anti-human neutrophil elastase (HNE) potency of CDSO3 was 0.43 μM. This high potency arose from lignin-like oligomerization, which was further potentiated by 6.6-fold due to sulfation. Mechanistically, this elastase inhibition was of mixed-type, time-dependent and more selective to positively charged elastases. The half-maximal anti-oxidative potency of CDSO3 was 3.52 μM, 4.8-fold potentiated from that of the monomer, caffeic acid (CA). In contrast, the half-maximal inhibitory potency to TNFα-induced inflammation was 5-10 μM, despite no activity with the monomer. More intriguingly, this anti-inflammatory activity was essentially identical with different stimuli, okadaic acid and hydrogen peroxide (H(2)O(2)), which implied that CDSO3 acts directly on inflammatory cascades within the cells. Overall, oligomerization and sulfation produced or significantly potentiated the activity, in comparison to the monomer. Thus, sulfated and unsulfated LMWLs are novel non-peptidic 2.8-4.1 kDa macromolecules that exhibit for the first time potent triple inhibitory activity against elastase, oxidation and inflammation, the three major pathogenic mechanisms known to cause emphysema.

A dominant-negative c-jun mutant inhibits lung carcinogenesis in mice

Lung cancer is the leading cause of cancer mortality in the United States and worldwide. The identification of key regulatory and molecular mechanisms involved in lung tumorigenesis is therefore critical to increase our understanding of this disease and could ultimately lead to targeted therapies to improve prevention and treatment. Induction of members of the activator protein-1 (AP-1) transcription factor family has been described in human non-small cell lung carcinoma. Activation of AP-1 can either stimulate or repress transcription of multiple gene targets, ultimately leading to increased cell proliferation and inhibition of apoptosis. In the present study, we show induction of AP-1 in carcinogen-induced mouse lung tumors compared with surrounding normal lung tissue. We then used a transgenic mouse model directing conditional expression of the dominant-negative c-jun mutant TAM67 in lung epithelial cells to determine the effect of AP-1 inhibition on mouse lung tumorigenesis. Consistent with low AP-1 activity in normal lung tissue, TAM67 expression had no observed effects in adult mouse lung. TAM67 decreased tumor number and overall lung tumor burden in chemically induced mouse lung tumor models. The most significant inhibitory effect was observed on carcinoma burden compared with lower-grade lesions. Our results support the concept that AP-1 is a key regulator of mouse lung tumorigenesis, and identify AP-1-dependent transcription as a potential target to prevent lung tumor progression.

The effect of an inhaled corticosteroid on glucose control in type 2 diabetes

OBJECTIVE

To determine the effect of inhaled corticosteroid (ICS) therapy on glucose control in adults with type 2 diabetes mellitus and coexisting asthma or chronic obstructive pulmonary disease (COPD).

DESIGN

A prospective randomized, double-blind, double-dummy placebo-controlled, crossover investigation of inhaled steroids and oral leukotriene blockers.

SETTING

A United States Department of Veterans Affairs Health Care System outpatient setting.

PARTICIPANTS

Adults with type 2 diabetes and asthma or COPD.

METHODS

Subjects (n=12) were randomized to receive either inhaled fluticasone propionate (440 microg twice daily) and oral placebo, or inhaled placebo and oral montelukast (10 mg/day). After 6 weeks, subjects were switched to the opposite therapy for 6 weeks. The primary outcome measure was the change in the percentage of glycosylated hemoglobin (%HbA1c) at 6 weeks relative to the baseline value.

RESULTS

Ten patients completed the study. The difference between the mean within-subject changes in %HbA1c associated with 6-week periods of fluticasone and the mean changes associated with montelukast therapy was small but statistically significant (mean difference=0.25; P<0.025). Neither fluticasone nor oral montelukast therapy for 6 weeks led to a significantly different mean % HbA1c compared with the relevant baseline (mean differences=0.11 and -0.14, respectively).

CONCLUSION

The absence of a clinically significant within-subject difference in the changes in %HbA1c associated with fluticasone versus oral montelukast therapy, or between either therapy or baseline does not warrant recommending changes in therapy for asthma or diabetes in patients with these co-morbid conditions. However, we suggest that clinicians carefully monitor blood glucose control when diabetic patients initiate ICS, especially with higher dosages.

Activation of the GDNF-inducible transcription factor (GIF) gene promoter by glucocorticoid and progesterone

Steroid hormones, especially glucocorticoids, exert physiologic effects on dopaminergic neurotransmission and have been implicated in several dopamine-mediated neuropsychiatric conditions. D(2) dopamine receptor gene expression is regulated by the zinc finger-type nuclear protein GDNF-inducible transcription factor (GIF). In this study, we sought to investigate if steroids could regulate transcription of the GIF gene itself. Transient co-transfection of the D(2) expressing neuroblastoma cell line NB41A3 with GIF promoter-luciferase constructs along with expression vectors for steroid hormone receptors showed that activation of glucocorticoid receptors but not estrogen receptors up-regulates transcription from the GIF promoter 5.0-fold. Progesterone receptors, which share the same consensus DNA recognition sequence as glucocorticoid receptors, also activated the GIF promoter. Serial 5'-deletion mutants of the GIF gene upstream region localized the glucocorticoid-responsive segment between nucleotides -128 and -66 relative to the transcription start site. This region contains a putative glucocorticoid-responsive element/progesterone-responsive element (GRE/PRE). Additionally, this fragment of the GIF gene 5'-upstream region activated the heterologous herpes simplex virus thymidine kinase (TK) promoter, which is known to be glucocorticoid and progesterone responsive. Furthermore, glucocorticoid receptor activation up-regulated endogenous GIF gene mRNA expression in NB41A3 cells. These observations demonstrate a molecular basis for glucocorticoid and progesterone-induced up-regulation of GIF gene transcription and provide a mechanism for the modulation of dopamine-mediated behaviors by these hormones.

Comparison of inhaled corticosteroids: an update

OBJECTIVE

To review the basis for the estimated comparative daily dosages of inhaled corticosteroids for children and adults that are presented in the National Heart, Lung, and Blood Institute's Expert Panel Report 3; in addition, the pharmacodynamic and pharmacokinetic basis for potential clinical differences among inhaled corticosteroids is discussed.

DATA SOURCES

A complete MEDLINE search was conducted of human studies of asthma pharmacotherapy published between January 1, 2001, and March 15, 2006, followed by a PubMed search up until August 2008, using ciclesonide, inhaled corticosteroids, and pharmacokinetics as key words. Product information on each inhaled corticosteroid was also included.

STUDY SELECTION AND DATA EXTRACTION

Comparative clinical trials of inhaled corticosteroids and systematic reviews for efficacy comparisons were evaluated. Extensive literature reviews, meta-analyses, and selected clinical studies that illustrate or represent specific points of view were selected. Pharmacodynamic and pharmacokinetic data extracted from previously published reviews and specific studies were included.

DATA SYNTHESIS

Pharmacodynamic characteristics (glucocorticoid receptor binding) and lung delivery determine the relative clinical efficacy and pharmacokinetic properties (oral bioavailability, lung retention, systemic clearance) and determine comparative therapeutic index of the inhaled corticosteroids. Secondary pharmacokinetic differences (intracellular fatty acid esterification, high serum protein binding) that have been posited to improve duration of action and/or therapeutic index are unproven, and current comparative clinical trials do not support the hypotheses that they provide an advantage. Ultrafine particle meter-dose inhalers (MDIs) have not demonstrated superior asthma control or improved safety over older MDIs. All of the inhaled corticosteroids demonstrate efficacy with once-daily dosing, and all are more effective when dosed twice daily.

CONCLUSIONS

Current evidence suggests that all of the inhaled corticosteroids have sufficient therapeutic indexes to provide similar efficacy and safety in low to medium doses. Whether or not some of the newer inhaled corticosteroids offer any advantages at higher doses has yet to be determined.

Inhaled corticosteroids for asthma: are they all the same?

OBJECTIVES

To assess similarities and differences among currently available inhaled corticosteroids (ICS) for treatment of asthma, with special emphasis on factors that may affect the relative safety of these medications.

METHODS

PubMed was searched for relevant reviews and original articles. Information from these studies was synthesized and critically assessed.

RESULTS

Differences in corticosteroid formulations and delivery systems can create variations in therapeutic efficacy. Chemical properties of the various corticosteroids may also affect their relative safety. Ciclesonide and beclomethasone dipropionate are administered as prodrugs activated by enzymes present in the lungs but not the oropharynx. Corticosteroid-specific adverse effects in the oropharynx are thus avoided, although formulation-specific effects may remain. Other adverse effects require systemic availability, either via the gastrointestinal tract or the lung. Once they enter the systemic circulation, all ICS are rapidly metabolized by the liver. Oral bioavailability of ICS such as fluticasone, ciclesonide and mometasone is minimal, as a result of their essentially complete first-pass metabolism in the liver. Ciclesonide also undergoes extrahepatic metabolism that eliminates it even more rapidly. Additionally, ciclesonide and mometasone exhibit very high levels of binding to serum proteins that reduces their ability to stimulate glucocorticoid receptors outside the lung.

CONCLUSIONS

Despite acting by similar mechanisms, currently available ICS and their delivery systems differ in ways that can potentially affect both safety and therapeutic effectiveness for individual patients.

Mechanism of upregulation of the inhibitory regulator, src-like adaptor protein (SLAP), by glucocorticoids in mast cells

Glucocorticoids suppress mast cell activation by inhibiting signaling events as well as transcription of cytokine genes. The inhibition of signaling events has been attributed to upregulation of inhibitory regulators such as Src-like adaptor protein1 (SLAP), downstream of tyrosine kinase1 (Dok1), and dual specificity protein phospahatase1 (DUSP1). As reported here, the upregulation of SLAP and Dok1, but not DUSP1, in the RBL-2H3 mast cell line was inhibited by actinomycin D and was thus dependent on gene transcription. Examination of the gene sequences revealed a glucocorticoid response element (GRE) and a half GRE as potential regulators of the SLAP and Dok1, respectively. As indicated by luciferase reporter assays, SLAP GRE, but not the Dok1 half GRE, robustly activated gene transcription after treatment of cells with glucocorticoids. Binding of the glucocorticoid receptor to the SLAP GRE was verified by chromatin immunoprecipitation assay. These findings further support the notion that the immunosuppressive actions of glucocorticoids are exerted in part through upregulation of inhibitory regulators by various mechanisms. In the case of SLAP specifically, this requires activation of gene transcription through the interaction of the glucocorticoid receptor with GRE.

The Raf-1 inhibitor GW5074 and dexamethasone suppress sidestream smoke-induced airway hyperresponsiveness in mice

BACKGROUND

Sidestream smoke is closely associated with airway inflammation and hyperreactivity. The present study was designed to investigate if the Raf-1 inhibitor GW5074 and the anti-inflammatory drug dexamethasone suppress airway hyperreactivity in a mouse model of sidestream smoke exposure.

METHODS

Mice were repeatedly exposed to smoke from four cigarettes each day for four weeks. After the first week of the smoke exposure, the mice received either dexamethasone intraperitoneally every other day or GW5074 intraperitoneally every day for three weeks. The tone of the tracheal ring segments was recorded with a myograph system and concentration-response curves were obtained by cumulative administration of agonists. Histopathology was examined by light microscopy.

RESULTS

Four weeks of exposure to cigarette smoke significantly increased the mouse airway contractile response to carbachol, endothelin-1 and potassium. Intraperitoneal administration of GW5074 or dexamethasone significantly suppressed the enhanced airway contractile responses, while airway epithelium-dependent relaxation was not affected. In addition, the smoke-induced infiltration of inflammatory cells and mucous gland hypertrophy were attenuated by the administration of GW5074 or dexamethasone.

CONCLUSION

Sidestream smoke induces airway contractile hyperresponsiveness. Inhibition of Raf-1 activity and airway inflammation suppresses smoking-associated airway hyperresponsiveness.

How corticosteroids control inflammation: Quintiles Prize Lecture 2005

Corticosteroids are the most effective anti-inflammatory therapy for many chronic inflammatory diseases, such as asthma but are relatively ineffective in other diseases such as chronic obstructive pulmonary disease (COPD). Chronic inflammation is characterised by the increased expression of multiple inflammatory genes that are regulated by proinflammatory transcription factors, such as nuclear factor-kappaB and activator protein-1, that bind to and activate coactivator molecules, which then acetylate core histones to switch on gene transcription. Corticosteroids suppress the multiple inflammatory genes that are activated in chronic inflammatory diseases, such as asthma, mainly by reversing histone acetylation of activated inflammatory genes through binding of liganded glucocorticoid receptors (GR) to coactivators and recruitment of histone deacetylase-2 (HDAC2) to the activated transcription complex. At higher concentrations of corticosteroids GR homodimers also interact with DNA recognition sites to active transcription of anti-inflammatory genes and to inhibit transcription of several genes linked to corticosteroid side effects. In patients with COPD and severe asthma and in asthmatic patients who smoke HDAC2 is markedly reduced in activity and expression as a result of oxidative/nitrative stress so that inflammation becomes resistant to the anti-inflammatory actions of corticosteroids. Theophylline, by activating HDAC, may reverse this corticosteroid resistance. This research may lead to the development of novel anti-inflammatory approaches to manage severe inflammatory diseases.

Effects of levocetirizine as add-on therapy to fluticasone in seasonal allergic rhinitis

BACKGROUND

Addition of H(1) antagonists to intranasal corticosteroid treatment of allergic rhinitis (AR) is common in clinical practice and recommended by guidelines, despite some evidence that the additive benefits are negligible.

OBJECTIVE

To assess additional benefits of 5 mg levocetirizine dihydrochloride in seasonal AR patients using 200 mcg fluticasone propionate nasal spray once daily.

METHODS

In a double-blind placebo-controlled crossover study of 27 patients, following 2 weeks without treatment, subjects used fluticasone with levocetirizine or identical placebo for 2 weeks each. Assessments were the Juniper mini Rhinoconjunctivitis Quality-of-Life Questionnaire (mini-RQLQ), domiciliary peak nasal inspiratory flow (PNIF), total nasal symptoms (TNS) scores and nasal nitric oxide concentrations. Effects were interpreted and tested against minimal clinically important differences.

RESULTS

Add-on effects for levocetirizine vs. placebo excluded any clinically significant benefits: mean effects (one sided 95% confidence intervals) were mini-RQLQ -0.11 (-0.34), PNIF +0.57 (+5.23), and TNS -0.11 (-0.60). Numbers needed to treat (95% confidence intervals) by outcome were mini-RQLQ 14 (5 to 49), PNIF 4 (3-7), and TNS 3 (2-6). No significant within or between treatment effects were seen for nasal nitric oxide.

CONCLUSION

Contrary to current practice, the present results demonstrate that for the majority of patients, antihistamine add-on to effective nasal steroid treatment is inappropriate. Further work is required to confirm that this is also true in the most severe cases, and the available evidence needs to be put into guidelines and implemented.

Rapid anti-secretory effects of glucocorticoids in human airway epithelium

Glucocorticoids are anti-inflammatory molecules classically described as acting through a genomic pathway. Similar to many steroid hormones, glucocorticoids also induce rapid non-genomic responses. The present paper provides a general overview of the rapid non-genomic effects of glucocorticoids in airway and will be mainly focused on a retrospective of the authors work on rapid effects of glucocorticoids in airway epithelial cell transport. Using fluorescence microscopy, short circuit current measurements in human bronchial epithelial (16HBE14o(-)) cells, we reported rapid non-genomic effects of dexamethasone on cell signalling and ion transport. Dexamethasone (1 nM) rapidly stimulated Na(+)/H(+) exchanger activity and pH(i) regulation in 16HBE14o(-) cells. Dexamethasone also produced a rapid decrease of intracellular [Ca(2+)](i) to a new steady state concentration and inhibited the large and transient [Ca(2+)](i) increase induced by apical adenosine tri-phosphate (ATP). Dexamethasone also reduced by 1/3 the Ca(2+)-dependent Cl(-) secretion induced by apical ATP. The rapid effects of dexamethasone on intracellular pH and Ca(2+) were not affected by inhibitors of transcription, cycloheximide or by the classical glucocorticoid and mineralocorticoid receptors antagonists, RU486 and spironolactone, respectively. The rapid responses to glucocorticoid were reduced by the inhibitors of adenylated cyclase, cAMP-dependent protein kinase (PKA) and mitogen-activated protein kinase (ERK1/2). Our results demonstrate, that dexamethasone at low concentrations, rapidly regulates intracellular pH, Ca(2+) and PKA activity and inhibits Cl(-) secretion in human bronchial epithelial cells via a non-genomic mechanism which neither involve the classical glucocorticoid nor mineralocorticoid receptor.

A canine model of cutaneous late-phase reactions: prednisolone inhibition of cellular and cytokine responses

Immunoglobulin E (IgE)-mediated late-phase reactions can be induced in atopic humans by intradermal injection of relevant allergens or anti-IgE antibodies. The histology of these reactions resembles that of naturally occurring atopic dermatitis. Strikingly similar responses can be induced in dogs, suggesting that a canine model could prove valuable for preclinical investigation of drugs targeting late-phase reactions. This study was designed to characterize the cellular, cytokine and chemokine responses after intradermal anti-IgE injection in untreated and prednisolone-treated dogs. Normal beagles were untreated or treated with prednisolone before intradermal injection of polyclonal rabbit anti-canine IgE or normal rabbit IgG. Biopsies were taken before injection and 6, 24 and 48 hr after injection. Samples were evaluated by histological and immunohistochemical staining, as well as by real-time quantitative polymerase chain reaction analysis. Dermal eosinophil and neutrophil numbers increased dramatically within 6 hr after injection of rabbit anti-canine IgE, and remained moderately elevated at 48 hr. The numbers of CD1c(+) and CD3(+) mononuclear cells were also increased at 6 hr. The real-time quantitative polymerase chain reaction demonstrated marked increases in mRNA expression for interleukin-13 (IL-13), CCL2, CCL5 and CCL17. Levels of mRNA for IL-2, IL-4, IL-6 and IFN-gamma did not change within the limits of detection. Prednisolone administration suppressed the influx of neutrophils, eosinophils, CD1c(+) and CD3(+) cells, as well as expression of IL-13, CCL2, CCL5 and CCL17. These data document the cytokine and chemokine responses to anti-IgE injection in canine skin, and they demonstrate the ability of the model to characterize the anti-inflammatory effects of a known therapeutic agent.

beta2-Adrenoceptor agonist modulates endothelin-1 receptors in human isolated bronchi

Chronic exposure of human isolated bronchi to beta(2)-adrenergic agonists, especially fenoterol, potentiates smooth muscle contraction in response to endothelin-1 (ET-1), a peptide implicated in chronic inflammatory airway diseases. Our objective was to determine whether ET-1 receptors ETA and ETB are involved in fenoterol enhancement. Twenty-two human bronchi were sensitized to ET-1 by prolonged incubation with 0.1 microM fenoterol (15 h, 21 degrees C). Removing the epithelium after fenoterol incubation limited the maximal contraction (0.10+/-0.36 g without epithelium versus 1.18+/-0.22 with, n=8, P=0.04). After 15 h incubation, 14 and 8 paired rings were fixed, respectively, for immunolabeling of bronchial ETA and ETB receptors, and to determine the mRNA expression levels using real-time quantitative reverse transcription polymerase chain reaction. ETA and ETB receptor mRNA expressions were 1.27- +/- 0.14-fold (not significant) and 2.24- +/- 0.28-fold (P<0.01) higher, respectively, in fenoterol-treated bronchi than in paired controls. Fenoterol incubation significantly increased epithelial ETA and ETB receptor labeling intensity scores (P=0.001 and P=0.002, respectively, versus controls), and enhanced the diffuse localization of ETA receptors on the epithelial cells (P=0.002 versus controls), but did not change the ETB-receptor immunolabeling intensity on airway smooth muscle. We conclude that fenoterol-induced sensitization of human isolated bronchi involves epithelial ETA and ETB receptors, which suggests perturbation of the epithelial regulation of airway smooth muscle contraction in response to ET-1.

Ophthalmic drug design based on the metabolic activity of the eye: soft drugs and chemical delivery systems

Despite its apparent easy accessibility, the eye is, in fact, well protected against the absorption of foreign materials, including therapeutic agents, by the eyelids, by the tear-flow, and by the permeability barriers imposed by the cornea on one side and the blood-retinal barrier on the other. Most existing ophthalmic drugs were adapted from other therapeutic applications and were not specifically developed for the treatment of eye diseases; hence, they are not well suited to provide eye-specific effects without causing systemic side effects. A real breakthrough in the area of ophthalmic therapeutics can be achieved only by specifically designing new drugs for ophthalmic applications to incorporate the possibility of eye targeting into their chemical structure. Possibilities provided along these lines by designing chemical delivery systems (CDSs) and soft drugs within the framework of retrometabolic drug design are reviewed here. Both are general concept applicable in almost any therapeutic area. This review will concentrate on beta-adrenergic agonists and anti-inflammatory corticosteroids, where clinical results obtained with new chemical entities, such as betaxoxime, adaprolol, loteprednol etabonate, and etiprednol dicloacetate, exist to support the advantages of such metabolism-focused, ophthalmic-specific drug design approaches.

Glucocorticoids suppress transcriptional up-regulation of bradykinin receptors in a murine in vitro model of chronic airway inflammation

BACKGROUND

Glucocorticoids are effective drugs for controlling symptoms and airway inflammation in respiratory diseases such as asthma and chronic obstructive pulmonary disease. However, the mechanisms behind their effects are not fully understood. We have recently demonstrated that prolonged exposure to the pro-inflammatory mediator tumour necrosis factor-alpha (TNF-alpha) markedly enhanced contractile responses to des-Arg9-bradykinin (selective bradykinin B1 receptor agonist) and bradykinin (selective bradykinin B2 receptor agonist) in murine airways. This increase was paralleled with elevated mRNA levels for bradykinin B1 and B2 receptors, a process involving intracellular mitogen-activated protein kinase pathways.

OBJECTIVE

To investigate the effects of glucocorticoids on the TNF-alpha up-regulated bradykinin B1 and B2 receptor response.

METHODS

Tracheal segments from BALB/c J mice were cultured with and without TNF-alpha, in the absence and presence of the transcriptional inhibitor actinomycin D or the glucocorticoid, dexamethasone. The contractile response induced by des-Arg9-bradykinin and bradykinin was subsequently assessed in a myograph system and mRNA for bradykinin B1 and B2 receptors was quantified using real-time polymerase chain reaction.

RESULTS

Actinomycin D abolished and dexamethasone concentration-dependently suppressed the TNF-alpha-induced enhancement of the des-Arg9-bradykinin and bradykinin responses. This was paralleled by a reduction of the mRNA expression for the bradykinin B1 and B2 receptors.

CONCLUSION

The presented data suggests the involvement of transcriptional mechanisms in the up-regulation of bradykinin B1 and B2 receptors during asthmatic airway inflammation, as well as in their down-regulation following glucocorticoid treatment.

The interrelationship between markers of inflammation and oxidative stress in chronic obstructive pulmonary disease: modulation by inhaled steroids and antioxidant

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is accompanied by both airway and systemic inflammation and by oxidative stress. This study aimed to characterise the relationship between oxidative stress and inflammatory components in induced sputum and blood.

MATERIAL & METHODS

We studied blood and sputum samples from stable COPD patients (mean FEV1 60.5+/-7.5% predicted) at baseline (no treatment) and after 10 weeks treatment with either inhaled steroid, fluticasone propionate (FP) (1000 microg/d) or 10 weeks treatment with N-acetylcysteine (600mg/d) (NAC). We assessed the inflammatory markers (IL-8, ECP, sICAM-1, NE) in sputum and serum and we compared them with blood markers of oxidative stress (SOD, GPx, TEAC, albumin, vitamin E and A).

RESULTS

At baseline blood sICAM-1 correlated with IL-8 levels (P<0.01, r = 0.62) and negatively with GPx (P<0.01, r = -0.63) and with TEAC (P<0.05, r = -0.53). TEAC correlated positively with GPx (P<0.01, r = 0.70). Correlation between sICAM and IL-8 disappeared after NAC treatment. The correlation between sICAM and GPx disappeared after FP treatment. The correlation between TEAC and GPx was maintained after both NAC and FP.

CONCLUSIONS

The relationship between markers of inflammation, adhesion and antioxidant capacity is significantly modulated by treatment with N-acetylcysteine or inhaled corticosteroids.

Pharmacokinetics and pharmacodynamics of systemically administered glucocorticoids

Glucocorticoids have pleiotropic effects that are used to treat diverse diseases such as asthma, rheumatoid arthritis, systemic lupus erythematosus and acute kidney transplant rejection. The most commonly used systemic glucocorticoids are hydrocortisone, prednisolone, methylprednisolone and dexamethasone. These glucocorticoids have good oral bioavailability and are eliminated mainly by hepatic metabolism and renal excretion of the metabolites. Plasma concentrations follow a biexponential pattern. Two-compartment models are used after intravenous administration, but one-compartment models are sufficient after oral administration.The effects of glucocorticoids are mediated by genomic and possibly nongenomic mechanisms. Genomic mechanisms include activation of the cytosolic glucocorticoid receptor that leads to activation or repression of protein synthesis, including cytokines, chemokines, inflammatory enzymes and adhesion molecules. Thus, inflammation and immune response mechanisms may be modified. Nongenomic mechanisms might play an additional role in glucocorticoid pulse therapy. Clinical efficacy depends on glucocorticoid pharmacokinetics and pharmacodynamics. Pharmacokinetic parameters such as the elimination half-life, and pharmacodynamic parameters such as the concentration producing the half-maximal effect, determine the duration and intensity of glucocorticoid effects. The special contribution of either of these can be distinguished with pharmacokinetic/pharmacodynamic analysis. We performed simulations with a pharmacokinetic/pharmacodynamic model using T helper cell counts and endogenous cortisol as biomarkers for the effects of methylprednisolone. These simulations suggest that the clinical efficacy of low-dose glucocorticoid regimens might be increased with twice-daily glucocorticoid administration.

Efficacy of oral and intravenous dexamethasone in horses with recurrent airway obstruction

REASONS FOR PERFORMING STUDY

Although the efficacy of dexamethasone for the treatment of recurrent airway obstruction (RAO) has been documented, the speed of onset of effect and duration of action are unknown, as is the efficacy of orally administered dexamethasone with or without fasting.

OBJECTIVES

To document the time of onset of effect and duration of action of a dexamethasone solution i.v. or orally with and without fasting.

METHODS

Protocol 1 used 8 RAO-affected horses with airway obstruction in a crossover design experiment that compared the effect of i.v. saline and dexamethasone (0.1 mg/kg bwt) on pulmonary function over 4 h. Protocol 2 used 6 similar horses to compare, in a crossover design, the effects of dexamethasone i.v. (0.1 mg/kg bwt), dexamethasone per os (0.164 mg/kg bwt) with and without prior fasting, and dexamethasone per os (0.082 mg/kg) with fasting.

RESULTS

Dexamethasone i.v. caused significant improvement in lung function within 2 h with a peak effect at 4-6 h. Dexamethasone per os was effective within 6 h with peak effect at 24 h at a dose of 0.164 mg/kg bwt prior to feeding. The duration of effect was, for all dexamethasone treatments, statistically significant for 30 h when compared to saline and tended to have a longer duration of effect when used orally. Dexamethasone per os at a dose of 0.164 mg/kg bwt to fed horses had mean effects comparable to dexamethasone at a dose of 0.082 mg/kg bwt per os given to fasted horses, indicating that feeding decreases bioavailability.

CONCLUSIONS

Dexamethasone administered i.v. has a rapid onset of action in RAO-affected horses. Oral administration of a bioequivalent dose of the same solution to fasted horses is as effective as i.v. administration and tends to have longer duration of action. Fasting horses before oral administration of dexamethasone improves the efficacy of treatment.

POTENTIAL RELEVANCE

Oral administration to fasted horses of a dexamethasone solution intended for i.v. use provides an effective treatment for RAO-affected animals.

Les glucocorticoïdes et leur récepteur : mécanismes d'action et conséquences cliniques

BACKGROUND

Glucocorticoids are used as anti-inflammatory, immuno-modulatory, anti-proliferative and cytotoxic drugs, but they also trigger important side-effects. These hormones bind to glucocorticoid receptor alpha (GRalpha), an intracellular protein, which acts essentially in the nucleus.

MAIN POINTS

GRalpha is a ligand-activated transcription factor that positively or negatively regulates gene expression by distinct mechanisms. Stimulation of gene transcription occurs after direct binding of the receptor to specific responsive DNA elements. Gene activation by glucocorticoids is mainly responsible for certain adverse effects. In contrast, the therapeutic effects of glucocorticoids are predominantly mediated through repression of genes encoding inflammatory mediators. Inhibitory protein-protein interaction between the hormone-activated receptor and the transcription factors NF-kappaB and AP-1 was found to be the underlying mechanism. However, inhibition of other transcription factors may account for deleterious effects of glucocorticoids, such as adrenal suppression and osteoporosis. GRalpha also mediates rapid non-genomic effects of glucocorticoids. Side-effects are reduced by using topical glucocorticoids which have a low systemic bioavailability. Moreover, it is important to determine the lowest effective maintenance dose of systemic and topical glucocorticoids to further decrease the risk of adverse effects. This is particularly justified because inhibition of AP-1 and NF-kappaB activities, that is the anti-inflammatory effect, occurs at much lower hormone concentrations than transactivation.

PERSPECTIVES

Clinical use of glucocorticoids is limited by occurrence of severe adverse effects. Therefore, the current aim is to design GRalpha ligands that retain only the anti-inflammatory activities of GC.

Inhibition of chemokine production from human airway smooth muscle cells by fluticasone, budesonide and beclomethasone

Human airway smooth muscle cells (HASMC) contribute to the process of airway wall remodelling in asthma by virtue of their secretory functions. This study was performed to investigate the effectiveness of the commonly used steroids beclomethasone, budesonide and fluticasone in downregulating HASMC production of RANTES and IL-8. HASMC (n=5) were cultured from dissected bronchi using collagenase digestion. Confluent HASMC were exposed to TNFalpha and IL-1beta (10 ng/ml) for 24 h. All stimulations were set with and without pre-treatment with beclomethasone, budesonide or fluticasone for 2 h at concentrations of 10(-9)-10(-6)M. IL-8 and RANTES mRNA expression was assessed by RT-PCR and protein secretion was determined by ELISA. Pre-treatment with beclomethasone, budesonide or fluticasone reduced TNFalpha- and IL-1beta-stimulated IL-8 and RANTES release from HASMC in a dose dependent manner. However, beclomethasone was 22-28% less effective than fluticasone and budesonide in inhibiting chemokine production. TNFalpha- and IL-1beta-induced RANTES and IL-8 expression was reduced on the transcriptional level by pre-treatment with fluticasone and budesonide. The results suggest that the topical steroids fluticasone, budesonide and to a lesser extent beclomethasone may have beneficial effects on airway inflammation in asthma by reducing RANTES and IL-8-induced leukocyte infiltration into the airway wall.

Pharmaceutical characteristics that influence the clinical efficacy of inhaled corticosteroids

BACKGROUND

Inhaled corticosteroids (ICSs) are the most effective therapy for the management of persistent asthma. The aim of ICS therapy is to achieve a high anti-inflammatory effect in the airways with a concomitant low risk of unwanted local and systemic effects. Direct estimates of clinical efficacy and potency based on studies in humans are difficult to interpret.

OBJECTIVE

To examine the challenges of using alternative estimates of ICS efficacy and potency, including pharmaceutical characteristics.

DATA SOURCES AND STUDY SELECTION

Articles published from 1990 to 2002 on the potency, efficacy, and tolerability of ICSs were identified using MEDLINE and in-house databases and were then reviewed. Search terms included inhaled corticosteroid, budesonide, fluticasone, beclomethasone, mometasone, and potency.

RESULTS

Differences among ICSs can be readily shown using preclinical measures, such as glucocorticoid receptor binding or skin blanching tests. However, pharmaceutical (delivery and pharmacokinetic) differences of ICSs can have a greater impact on clinical efficacy than in vitro potency differences. For example, the unique esterification of budesonide in the airways prolongs its local activity and may contribute positively to its efficacy and therapeutic index. Although comparative clinical trials suggest 6-fold differences in potencies among ICSs, there is currently no evidence to support differences in efficacy when they are administered at equipotent dosages.

CONCLUSIONS

Greater preclinical potency of an ICS does not imply greater clinical efficacy. Pharmacokinetic factors can have a significant impact on relative clinical efficacy.

Beta-adrenergic agonists inhibit corticosteroid-induced apoptosis of airway epithelial cells

Airway epithelial damage is a feature of persistent asthma. Treatment with inhaled and oral corticosteroids may suppress inflammation and gain clinical control despite continued epithelial damage. We have previously demonstrated that corticosteroids elicit apoptosis of airway epithelial cells in culture. beta-Adrenergic receptor agonists are commonly used in asthma therapy and can inhibit corticosteroid-induced apoptosis of eosinophils. We tested the hypothesis that beta-adrenergic agonists would inhibit corticosteroid-induced airway epithelial cell apoptosis in cultured primary airway epithelial cells and in the cell line 1HAEo-. Albuterol treatment inhibited dexamethasone-induced apoptosis completely but did not inhibit apoptosis induced by Fas receptor activation. The protective effect of albuterol was duplicated by two different analogs of protein kinase A. The protective effect was not associated with increased translocation of the glucocorticoid receptor to the nucleus nor with changes in glucocorticoid receptor-mediated transcriptional activation or repression. We demonstrate that beta-adrenergic agonists can inhibit corticosteroid-induced apoptosis but not apoptosis induced by Fas activation. These data suggest that one potential deleterious effect of corticosteroid therapy in asthma can be prevented by concomitant beta-adrenergic agonist treatment.

Fluticasone propionate and mometasone furoate have equivalent transcriptional potencies

BACKGROUND

Glucocorticoids exert their anti-inflammatory effects mainly through transrepression of the transcription factors activator protein-1 (AP-1) and nuclear factor-kappa B (NF-kappaB). Certain adverse effects of glucocorticoids are mediated through gene transactivation. Fluticasone propionate (FP) and mometasone furoate (MF) are the most recently developed topical glucocorticoids for the treatment of airway disorders. Their relative capacities to repress AP-1 and NF-kappaB activities are not known and comparison of their transactivation potencies has given unclear results.

OBJECTIVE

To determine the relative transactivation and transrepression potencies of FP and MF.

METHODS

Transactivation assays were performed in HeLa cells carrying a glucocorticoid-inducible luciferase gene. To measure transrepressive potencies of FP and MF, A549 lung epithelial cells were transiently transfected with an AP-1- or NF-kappaB-dependent luciferase gene. Using an immunoassay, we also evaluated the ability of MF and FP to inhibit the production of Regulated upon Activation, Normal T-cell Expressed and Secreted (RANTES), a pro-inflammatory cytokine, whose gene is controlled by AP-1 and NF-kappaB. Areas under the dose-response curve were calculated to determine relative potencies.

RESULTS

FP and MF are equipotent for transactivation. Both molecules show globally the same potency to inhibit AP-1 and NF-kappaB activities and RANTES production. MF and FP have very significant transcriptional effects at 2x10(-10) M, which is the peak concentration reached in the plasma after inhalation of high dosages. Indeed, they produce a 17-fold induction of luciferase in the transactivation assay, and inhibit AP-1 activity, NF-kappaB activity and RANTES release by approximately 40%.

CONCLUSION

FP and MF have the same ability to trigger gene activation and also the same potency to inhibit AP-1 and NF-kappaB activities. Their strong transcriptional effects at 2x10(-10) M suggest that these compounds act not only topically but also systemically, with the risk of provoking concomitant adverse effects at high dosages.

Inhaled glucocorticoids and adrenal function: an update

For the vast majority of asthmatic children, treatment with inhaled glucocorticoids is safe and effective. Mild impairment of adrenal function of doubtful clinical significance is known to occur in some children inhaling > or = 400 micro g/day budesonide and beclomethasone or > or = 200 micro g fluticasone. Recent reports of life-threatening adrenal failure in asthmatic children inhaling glucocorticoids, some of whom were prescribed licensed doses, have prompted the recommendation that the use of high-dose inhaled glucocorticoids, particularly fluticasone, should be avoided. However, the importance of correctly diagnosing asthma, of using the minimum dose of inhaled glucocorticoid required for symptom control and of regular growth-velocity assessment cannot be over-emphasised. Appropriate asthma management including the early introduction of steroid-sparing agents such as a long-acting beta-agonist or leukotriene antagonist may reduce the morbidity associated with inhaled glucocorticoid use but some children, for reasons as yet unknown, may exhibit increased sensitivity to the systemic effects of inhaled glucocorticoid treatment. Possible explanations for this, with reference to the pharmacology and molecular mechanisms of glucocorticoid action, are accompanied in this review by a summary of the recent case reports and discussion of assessment of adrenal function.

Oral candidiasis associated with inhaled corticosteroid use: comparison of fluticasone and beclomethasone

BACKGROUND

Inhaled steroids such as fluticasone propionate and beclomethasone dipropionate play a central role in the treatment of bronchial asthma. Fluticasone exhibits excellent clinical effectiveness; however, oral adverse effects can occur.

OBJECTIVE

To compare the frequency of oral candidiasis in asthmatic patients treated with fluticasone and beclomethasone, to evaluate the effect of gargling with amphotericin B, and to measure the inhalation flow rate on candidiasis.

METHODS

The study consisted of 143 asthmatic patients who were treated with inhaled steroids, 11 asthmatic patients not treated with inhaled steroids, and 86 healthy volunteers. Quantitative fungal culture was performed by aseptically obtaining a retropharyngeal wall swab from these patients. Patients with positive results were treated with gargling using a 1:50 dilution amphotericin B solution. In asthmatic patients treated with fluticasone, the inhalation flow rate was measured using an inspiratory flow meter.

RESULTS

The amount of Candida spp. was significantly greater in asthmatic patients taking inhaled steroids compared with those who were not. It was also significantly greater in patients with oral symptoms than asymptomatic patients and significantly greater in asthmatic patients treated with fluticasone than in those treated with beclomethasone. Although the presence of Candida did not correlate with the inhaled dose of beclomethasone, it did increase with the dose of fluticasone. Gargling with amphotericin B was effective in most asthmatic patients with candidiasis. Candidiasis was not due to inappropriate flow rates during inhalation of steroids.

CONCLUSIONS

Fungal culture of a retropharyngeal wall swab may be useful for predicting the risk of developing oral candidiasis in asthmatic patients treated with inhaled steroids. The amount of isolated Candida was significantly greater in asthmatic patients treated with fluticasone than in those treated with beclomethasone. Attention to dosage is required as the amount of Candida increased with dose of fluticasone. Gargling with a 1:50 dilution of amphotericin B is effective in treating oral candidiasis of asthmatic patients treated with inhaled steroids.

In vitro sensitization of human bronchus by beta2-adrenergic agonists

Incubation of human distal bronchi from 48 patients for 15 h with 10(-7) M fenoterol induced sensitization characterized by an increase in maximal contraction to endothelin-1 (ET-1) and acetylcholine (ACh). Incubation of human bronchi with 10(-6), 3 x 10(-6), and 10(-5) M forskolin (an adenyl cyclase activator) reproduced sensitization to ET-1 and ACh. The sensitizing effect of fenoterol was inhibited by coincubation with gliotoxine (a nuclear factor-kappaB inhibitor), dexamethasone, indomethacin (a cyclooxygenase inhibitor), GR-32191 (a TP prostanoid receptor antagonist), MK-476 (a cysteinyl leukotriene type 1 receptor antagonist), SR-140333 + SR-48968 + SR-142801 (neurokinin types 1, 2, and 3 tachykinin receptor antagonists) with or without HOE-140 (a bradykinin B(2) receptor antagonist), SB-203580 (an inhibitor of the 38-kDa mitogen-activated protein kinase, p38(MAPK)), or calphostin C (a protein kinase C blocker). Our results suggest that chronic exposure to fenoterol induces proinflammatory effects mediated by nuclear factor-kappaB and pathways involving leukotrienes, prostanoids, bradykinin, tachykinins, protein kinase C, and p38(MAPK), leading to the regulation of smooth muscle contraction to ET-1 and ACh.

Transactivation assay for determination of glucocorticoid bioactivity in human serum

We have developed a mammalian cell (COS-1) bioassay, which measures glucocorticoid bioactivity (GBA) directly from a small amount of human serum. The assay is based on the expression of human glucocorticoid receptor (GR) together with a coactivator protein and reporter plasmid containing GR response elements upstream of the luciferase gene. Ten microliters of human serum, in duplicate, are added directly to the cell culture medium, and GBA is derived from reporter gene activity. The assay differentiates between biopotencies of synthetic steroids, and importantly, mifepristone (RU486) is able to block glucocorticoid-induced response. The assay is sensitive (<15.6 nM cortisol in fetal calf serum) and precise, with the within- and between-assay coefficients of variation less than 8% and 10%, respectively. We measured serum GBA (bioassay) and cortisol (RIA) levels in 34 asthmatic children (age range, 5.7-14.2 yr) at baseline and after treatment with either inhaled budesonide (800 microg/d, n = 14), fluticasone propionate (500 microg/d, n = 14), or cromones (control group, n = 6). Pretreatment serum GBA and cortisol levels correlated strongly (r = 0.90, P < 0.0001, n = 34). Two months of treatment with inhaled budesonide resulted in excess GBA in circulation, which was not attributable to endogenous cortisol (P < 0.001). In the fluticasone propionate group, the presence of serum excess GBA was at the borderline of statistical significance (P < 0.08) after 2 months of inhalation therapy, and no excess GBA was detected in the cromone group. In conclusion, our bioassay enables measurement of mammalian cell response to bioactive glucocorticoids in circulation and provides a novel means to investigate patients receiving drugs acting through the GR.

Selective enhancement of gene transfer by steroid-mediated gene delivery

The incorporation of transgenes into the host cells' nuclei is problematic using conventional nonviral gene delivery technologies. Here we describe a strategy called steroid-mediated gene delivery (SMGD), which uses steroid receptors as shuttles to facilitate the uptake of transfected DNA into the nucleus. We use glucocorticoid receptors (GRs) as a model system with which to test the principle of SMGD. To this end, we synthesized and tested several bifunctional steroid derivatives, finally focusing on a compound named DR9NP, consisting of a dexamethasone backbone linked to a psoralen moiety using a nine-atom chemical spacer. DR9NP binds to the GR in either its free or DNA-crosslinked form, inducing the translocation of the GR to the nucleus. The expression of transfected DR9NP-decorated reporter plasmids is enhanced in dividing cells: expression of steroid-decorated reporter plasmids depends on the presence of the GR, is independent of the transactivation potential of the GR, and correlates with enhanced nuclear accumulation of the transgene in GR-positive cells. The SMGD effect is also observed in cells naturally expressing GRs and is significantly increased in nondividing cell cultures. We propose that SMGD could be used as a platform for selective targeting of transgenes in nonviral somatic gene transfer.

Postnatal glucocorticoid therapy for prevention of bronchopulmonary dysplasia: routes of administration compared

Postnatal systemic and inhaled glucocorticoid therapies continue to be used in the management of bronchopulmonary dysplasia (BPD). Systemic dexamethasone therapy has been studied longer than aerosolized glucocorticoid therapy. Several prophylactic trials of systemic dexamethasone therapy demonstrated a reduction in the incidence of BPD and neonatal mortality. However, evidence of potentially serious acute and long-term adverse effects has reduced enthusiasm for use of systemic dexamethasone therapy. Although no trial to date of inhaled glucocorticoid therapy showed a reduction in the incidence of BPD, some studies demonstrated secondary pulmonary benefits with few short-term adverse effects. This article compares the clinical efficacy and safety of these two routes of administration of glucocorticoid therapy.

Is there a role for glucocorticoid receptor beta in asthma?

Glucocorticoids (GCs) are routinely used as anti-inflammatory drugs in the treatment of asthma. They act through binding to glucocorticoid receptor alpha (GRalpha), which represses numerous genes encoding pro-inflammatory mediators. A hormone binding deficient GR isoform named GRbeta has been isolated in humans. When overexpressed by transfection, GRbeta may function as a dominant negative modulator of GRalpha. However, to act as such, GRbeta has to be more abundant than GRalpha, and conflicting data have been obtained concerning the relative levels of the two isoforms in cell lines and freshly isolated cells. Moreover, the dominant negative effect was not confirmed by independent laboratories. In GC-resistant asthmatics, GRbeta was expressed by an increased number of peripheral blood mononuclear cells (PBMCs), airway T cells, and cells found in skin biopsies of tuberculin responses. However, the relative amounts of GRalpha and GRbeta in these cells were not determined. In GC-dependent asthmatics, PBMCs expressed GRalpha predominantly. No cells containing higher levels of GRbeta than GRalpha have yet been reported in asthmatics. Even if the existence of such cells is demonstrated, the role of GRbeta in asthma will remain a matter of controversy because functional studies have given discrepant data.