Edward M. Erin

A selective inhibitor of inducible nitric oxide synthase inhibits exhaled breath nitric oxide in healthy volunteers and asthmatics

The inducible isoenzyme of nitric oxide synthase (iNOS) generates nitric oxide (NO) in inflammatory diseases such as asthma. The prodrug L‐N6‐(1‐iminoethyl)lysine 5‐tetrazole amide (SC‐51) is rapidly converted in vivo to the active metabolite L‐N6‐(1‐iminoethyl)lysine (L‐NIL). Initially, we performed in vitro experiments in human primary airway epithelial cells to demonstrate that L‐NIL causes inhibition of iNOS. In a randomized double‐blind placebo‐controlled crossover trial, SC‐51 was administered as a single oral dose (20 or 200 mg) in separate cohorts of healthy volunteers (two groups of n=12) and mild asthmatic patients (two groups of n=12). SC‐51 (200 mg) reduced exhaled breath NO levels to <2 ppb in both healthy volunteers (P<0.001) and mild asthmatics (P<0.001) within 15 min, representing >90% inhibition of baseline levels of NO in asthmatic patients, with the effects lasting at least 72 h. There were no significant effects on blood pressure, pulse rate, or respiratory function (FEV1). This study demonstrates that an inhibitor of iNOS produces marked inhibition of exhaled breath NO in normal and asthmatic subjects without producing the side effects observed following the systemic administration of non‐selective NOS inhibitors, and thus provides support for the potential use of iNOS inhibitors to treat a range of inflammatory clinical disorders.

Topical corticosteroid inhibits interleukin‐4, ‐5 and ‐13 in nasal secretions following allergen challenge

Background Cytokines and chemokines produced by allergen‐reactive T‐helper type 2 (Th2) cells may be pivotal to the pathophysiology of allergic disorders.

Long-acting β2-adrenoceptor agonists or tiotropium bromide for patients with COPD: is combination therapy justified?

Bronchodilators are the mainstay of therapy for patients with established chronic obstructive pulmonary disease (COPD) but, at present, the majority of patients use short-acting agents. There is increasing evidence that long-acting agents, such as the beta(2)-adrenoceptor agonists salmeterol and formeterol, and the new anticholinergic tiotropium bromide provide a better therapeutic option. In the treatment of COPD, long-acting beta(2)-adrenoceptor agonists (LABAs) given twice daily cause the same degree of bronchodilation as tiotropium bromide given once daily. Combined use of an inhaled LABA with tiotropium bromide should provide important therapeutic benefits, as these drugs have distinct and complementary pharmacological actions in the airways. Although clinical trials of this combination have not been performed, clinical experience with Combivent, a combination of a short-acting beta(2)-adrenoceptor agonist (salbutamol) and a short-acting anticholinergic (ipratropium bromide), in COPD is encouraging because the bronchodilation produced is of a magnitude greater than that of either component alone. However, because LABAs are given twice daily but tiotropium bromide is required only once daily, the challenge is to develop a combined inhaler that can be employed on a daily basis.

Single dose topical corticosteroid inhibits IL-5 and IL-13 in nasal lavage following grass pollen challenge

Background:  Nasal lavage is a noninvasive method of obtaining inflammatory exudates following nasal allergen challenge (NAC), and permits cells and released mediators to be evaluated.

Effects of a reversible β-tryptase and trypsin inhibitor (RWJ-58643) on nasal allergic responses

Background β‐Tryptase is a multifunctional mast cell serine protease released during mast cell degranulation and tryptase/trypsin inhibitors are a novel potential therapeutic approach for allergic inflammatory diseases.

Noninvasive monitoring of airway inflammation and steroid reduction in children with asthma.

Purpose of review Management of pediatric asthma is currently based on symptoms (often a second-hand report from parents) and lung function. Inhaled steroids are the mainstay of asthma management targeted at controlling airway inflammation. They should be used in the lowest possible doses. A number of noninvasive methods to assess inflammation have been developed in an effort to optimize anti-inflammatory treatment. Recent findings The first longitudinal studies have been published demonstrating an improvement in asthma control in children by adding noninvasive monitoring of inflammation into the clinical management. New methods include exhaled nitric oxide measurements, induced sputum and markers in exhaled breath condensate. Summary Further studies will show the practicability of including these measurement methods into everyday clinical practice. Their addition to the conventional assessment of asthma control appears promising. Using these methods to evaluate the current inflammatory state seems obligatory in research into new asthma therapeutics and management strategies. Managing asthma in children in specialist practice relying only on symptoms and lung function is no longer state of the art.

Rapid effect of inhaled ciclesonide in asthma: a randomized, placebo-controlled study.

BACKGROUND Ciclesonide is a novel inhaled corticosteroid for the treatment of asthma, and it is important to measure the onset of effect of this therapy on airway hyperresponsiveness (AHR), exhaled nitric oxide (NO), and levels of eosinophils in induced sputum. METHODS In a randomized, double-blind, crossover study, 21 patients with mild asthma inhaled ciclesonide 320 microg (ex-actuator) qd, ciclesonide 640 microg (ex-actuator) bid, and placebo for 7 days. Exhaled NO and AHR to adenosine monophosphate (AMP), measured as the provocative concentration of AMP producing a 20% reduction in FEV1 (PC20FEV1), were assessed after inhalation on days 1, 3 and 7. Eosinophil levels in induced sputum were also measured. RESULTS Ciclesonide 320 microg qd and 640 microg bid produced significantly greater improvements in PC20FEV1 compared with placebo on day 1 (within 2.5 h), and on days 3 and 7 (all p < 0.0001). On day 3, both ciclesonide doses significantly reduced exhaled NO levels by - 17.7 parts per billion (p < 0.0001) and - 15.4 parts per billion (p < 0.003) vs placebo, respectively. Significant reductions were maintained during the study with both ciclesonide doses (p < 0.01). A nonsignificant trend towards a decrease in eosinophil cell numbers was observed after 7 days of ciclesonide treatment, especially in patients receiving the higher dose. CONCLUSIONS A single dose of ciclesonide decreased AHR to AMP and exhaled NO within 3 h, while FEV, improved at 3 days and 7 days.

Nasal testing for novel anti-inflammatory agents

The nose is much more accessible than the airways to assess the effects of anti-inflammatory therapy. Hence, it is possible to obtain repeated samples of nasal exudates and mucosa cells before and after nasal allergen challenge (NAC) in a relatively non-invasive way by techniques such as nasal lavage, filter paper, and nasal brushing and scraping. A comprehensive review of the extensive clinical research experience with these nasal methodologies has recently been published by Howarth et al. [1]. Nasal samples can then be analysed by novel semiautomated analytical methods to assess chemokines and cytokines, inflammatory mediators, mRNA, and transcription factors. Inhaled allergen challenge commonly calls a profound decrease in forced expiratory volume in 1 s, while the nasal symptoms that follow NAC are generally mild. Furthermore, it is much easier to recruit potential subjects with allergic rhinitis (AR) because of grass pollen outside the hayfever season, rather than subjects with a dual early and late reaction to an inhaled allergen. Following NAC it is possible to measure symptoms, use acoustic rhinomanometry, and measure levels of cells and mediators to evaluate new drugs for AR and asthma [2–4]. It has long been recognized that there is a strong functional and immunological relationship between the nose and bronchi [5, 6], especially in terms of infiltrating leucocytes and inflammatory mediators when comparing AR and allergic asthma [7]. The upper and lower airways have related respiratory epithelium and similar responses to allergen challenge. Indeed, AR and asthma commonly coexist [8], as allergy is a systemic disorder that can affect various organs within the unified immune system [9, 10]. This is in line with the WHO Initiative on Allergic Rhinitis and its Impact on Asthma (ARIA) stressing the concept of a single airway disease [11]. However, the nasal model involves a different vasculature to that in the airways, while the bronchi have added airway smooth muscle. At a pathological level, the extent of nasal remodelling in AR seems to be much less than that in the bronchi of asthmatic patients [12, 13]. There is strong evidence that allergen-reactive type 2 T helper (Th2) cells play an important role in the induction and maintenance of the allergic inflammatory cascade [14]. Cytokines and chemokines produced by Th2 cells (IL-4, IL-5, IL-9, and IL-13) may be pivotal to the pathophysiology of allergic disorders involving production of IgE, recruitment and activation of mast cells and eosinophils, mucus hypersecretion, subepithelial fibrosis, and tissue remodelling. Several studies have demonstrated significant expression of various cytokines and chemokines in inflammatory cells at sites of nasal allergic inflammation [15–19]. Excessive production of IL-5 and IL-13 may be critical to the allergic response [14, 20]. Maintenance treatment with topical steroids exerts a range of anti-inflammatory nasal effects on production of eotaxin [21], RANTES, MIP-1a, IL-8, IL-1b [17], TNF-a [22], and IL-5 [23]. Topical allergen challenge increases the levels of mucosal mRNA of IL-5 and IL-13 [19, 23] but nasal cytokines and chemokines may be produced at low concentration in nasal secretions, and may be undetectable when using conventional ELISAs. A single dose of topical corticosteroid has been shown to reduce levels of granulocyte macrophage-colony stimulating factor and IL-5 detected by absorption with filter paper following nasal challenge with grass pollen in AR [23, 24]. In order to sample nasal exudates for allergic inflammatory mediators, the classical methods of nasal lavage are those described by Naclerio et al. [25], the nasal pool method of Greiff et al. [26], and the use of a Foley’s catheter by Grünberg et al. [27]. Lavage is performed with saline at volumes between 1 and 10mL. The repeatability and validity of different nasal lavage methods have been compared [28]. An important demonstration of the utility of this methodology for assessing therapy was the demonstration that pretreatment with topical corticosteroids causes inhibition of release of histamine, kinins, and symptoms after NAC [29]. Peptidyl leukotrienes are also released [30] and there is a later increase in histamine during the late nasal reaction [31]. More recently, increases in IL-5 and eotaxin have been detected in nasal lavage fluid in the early and late reactions following NAC [21, 32]. In this edition of Clinical and Experimental Allergy, Rami Salib, Laurie Lau, and Peter Howarth demonstrate elegantly that nasal lavage levels of eotaxin-1 (CCL11) are elevated in symptomatic AR compared with controls [33]. Tommy Sim and colleagues have developed the use of filter paper strips, which are placed on the turbinates to absorb nasal secretions [34]. The nasal filter paper method has the advantage of directly sampling nasal secretions that are less diluted and can therefore pick up protein signals, which are below the detection limits of nasal lavage. The matrix or filter paper method has been used to measure chemokines and cytokines after NAC [17, 24, 35, 36]. However, it should be noted that nasal lavage probably represents an extracellular signal, while nasal sampling by absorption into filter paper strips probably represents both an intracellular and extracellular signal, as cells that adhere to the surface of the filter paper may lyse and release their intracellular contents. Cells samples may be obtained from the nasal mucosal using small nylon dental flossing brushes which are gently rotated over the epithelium; then the attached cells are dislodged in balanced salt solution [37, 38]. It has been demonstrated that nasal brushing can be used as an Clin Exp Allergy 2005; 35:981–985 doi:10.1111/j.1365-2222.2005.02311.x

New drugs for COPD based on advances in pathophysiology

There is a pressing need to develop new treatments for chronic obstructive pulmonary disease (COPD), as no currently available drug has been shown to reduce the relentless progression of this disease. Furthermore, recognition of the global importance and rising prevalence of COPD and the absence of effective therapies has now led to a concerted effort to develop new drugs for this disease [1, 2]. However, there have been disappointingly few therapeutic advances in the drug therapy of COPD, in contrast to the enormous advances made in asthma management that reflect a much better understanding of the underlying disease [3, 4].

Evaluation of New Drugs for Asthma and COPD: Endpoints, Biomarkers and Clinical Trial Designs

The incidence of both asthma and chronic obstructive pulmonary disease (COPD) is increasing throughout the world, and acts as a major incentive for the development of new and improved drug therapy. For the large range of bronchodilator and anti-inflammatory agents in current clinical development, reliable decision-making is imperative in phase II, before entering large-scale phase III clinical studies. With anti-inflammatory therapies for asthma, many studies have been performed utilising the inhaled allergen challenge as a proof of concept study, effects on airway hyper-reactivity (AHR) can be assessed, and it is also possible to directly study limited numbers of symptomatic asthma patients. Additional clinical trial designs in asthma include studies to assess bronchodilation, bronchoprotection against a variety of inhaled constrictor agents, exercise tolerance, add-on and titration studies with inhaled and oral corticosteroids, and prevention and treatment of exacerbations. In contrast, it is a major issue for the development of new anti-inflammatory drugs for COPD that large-scale phase II studies are generally required in this disease in order to detect clinical efficacy. In COPD, clinical trial designs range from studies on lung function, symptoms and exercise performance, inflammatory biomarkers, natural history of chronic stable disease, prevention and treatment of exacerbations, and effects on cachexia and muscle function. Compared with asthma, inclusion criteria, monitoring parameters, comparator therapies and trial design are less well established for COPD. The large variety of potential clinical endpoints includes lung function, symptoms, walking tests, hyperinflation, health-related quality of life (HR-QOL), airway reactivity, and frequency and severity of exacerbations. In addition, surrogate biomarkers may be assessed in blood, exhaled breath, induced sputum, bronchial mucosal biopsy and bronchoalveolar lavage (BAL), and advanced radiographic imaging employed. Of particular utility is ex vivo whole blood stimulation to enable pharmacokinetic/pharmacodynamic modelling in establishing an optimal dosage regimen relatively early in human clinical studies. There have been considerable recent advances in the development of non-invasive biomarkers and novel clinical trial designs, as well as clarification of regulatory requirements, that will facilitate the development of new therapies for patients with asthma and COPD.