Pharmacology of airway inflammation in asthma and COPD

Tobacco introduced Perilla frutescens and Ocimum basilicum genes attenuates neutrophilic inflammation in lung tissues of COPD rats

The new-type tobacco varieties "Zisu" and "Luole" were obtained by distant hybridization between N. tabacum L. var. HHY and Perilla frutescens and Ocimum basilicum, with obviously different chemical composition. Smoking is the major risk factor for COPD, characterized by neutrophil-dominant inflammation. In the present study, rat COPD model was established by cigarette exposure, and the health hazard of three varieties was compared by general condition observation, pathological and morphological evaluation, total and differential cell numeration, and characterization of major inflammatory mediators and MAPK/NF-κB pathway, etc. Rats in "HHY" group developed obvious symptoms such as cough, dyspnea, mental fatigue, etc., but these symptoms were obviously mitigated in "Zisu" and "Luole" groups. H&E staining analysis, including score, MLI, MAN, wt% and WA%, showed that "Zisu" and "Luole" significantly alleviated lung injury and the degree of airway remodeling and emphysema compared to "HHY". In BALF, the number of total leukocyte and the percent neutrophils in "Zisu" and "Luole" groups were evidently lower than "HHY" group. The levels of inflammatory mediators, such as IL-8, MPO, MIP-2, LTB4, TNF-α and neutrophil elastase, in "HHY" group were obviously higher than "Zisu" and "Luole" groups. The ROS-mediated NF-κB p65 and p38MAPK pathways may play an important role. Results indicated that tobacco introduced perilla and basil genes could remarkably attenuate recruitment, infiltration and activation of neutrophils and intervene in airway inflammation, retarding disease progression, especially "Zisu". Changes in chemical composition via breeding techniques may be a novel way for tobacco harm reduction.

Corticosteroid resistance in asthma: Cellular and molecular mechanisms

Inhaled glucocorticoids (GCs) are drugs widely used as treatment for asthma patients. They prevent the recruitment and activation of lung immune and inflammatory cells and, moreover, have profound effects on airway structural cells to reverse the effects of disease on airway inflammation. GCs bind to a specific receptor, the glucocorticoid receptor (GR), which is a member of the nuclear receptor superfamily and modulates pro- and anti-inflammatory gene transcription through a number of distinct and complementary mechanisms. Targets genes include many pro-inflammatory mediators such as chemokines, cytokines, growth factors and their receptors. Inhaled GCs are very effective for most asthma patients with little, if any, systemic side effects depending upon the dose. However, some patients show poor asthma control even after the administration of high doses of topical or even systemic GCs. Several mechanisms relating to inflammation have been considered to be responsible for the onset of the relative GC resistance observed in these patients. In these patients, the side-effect profile of GCs prevent continued use of high doses and new drugs are needed. Targeting the defective pathways associated with GC function in these patients may also reactivate GC responsiveness.

Clinical Role of Extraoral Bitter Taste Receptors

Humans can recognise five basic tastes: sweet, sour, salty, bitter and umami. Sour and salty substances are linked to ion channels, while sweet, bitter and umami flavours are transmitted through receptors linked to the G protein (G protein-coupled receptors; GPCRs). There are two main types of GPCRs that transmit information about sweet, umami and bitter tastes-the Tas1r and TAS2R families. There are about 25 functional TAS2R genes coding bitter taste receptor proteins. They are found not only in the mouth and throat, but also in the intestines, brain, bladder and lower and upper respiratory tract. The determination of their purpose in these locations has become an inspiration for much research. Their presence has also been confirmed in breast cancer cells, ovarian cancer cells and neuroblastoma, revealing a promising new oncological marker. Polymorphisms of TAS2R38 have been proven to have an influence on the course of chronic rhinosinusitis and upper airway defensive mechanisms. TAS2R receptors mediate the bronchodilatory effect in human airway smooth muscle, which may lead to the creation of another medicine group used in asthma or chronic obstructive pulmonary disease. The discovery that functionally compromised TAS2R receptors negatively impact glucose homeostasis has produced a new area of diabetes research. In this article, we would like to focus on what facts have been already established in the matter of extraoral TAS2R receptors in humans.

Arpin is critical for phagocytosis in macrophages and is targeted by human rhinovirus

Human rhinovirus is a causative agent of severe exacerbations of chronic obstructive pulmonary disease (COPD). COPD is characterised by an increased number of alveolar macrophages with diminished phagocytic functions, but how rhinovirus infection affects macrophage function is still unknown. Here, we describe that human rhinovirus 16 impairs bacterial uptake and receptor-mediated phagocytosis in macrophages. The stalled phagocytic cups contain accumulated F-actin. Interestingly, we find that human rhinovirus 16 downregulates the expression of Arpin, a negative regulator of the Arp2/3 complex. Importantly, re-expression of the protein rescues defective internalisation in human rhinovirus 16-treated cells, demonstrating that Arpin is a key factor targeted to impair phagocytosis. We further show that Arpin is required for efficient uptake of multiple targets, for F-actin cup formation and for successful phagosome completion in macrophages. Interestingly, Arpin is recruited to sites of membrane extension and phagosome closure. Thus, we identify Arpin as a central actin regulator during phagocytosis that it is targeted by human rhinovirus 16, allowing the virus to perturb bacterial internalisation and phagocytosis in macrophages.

Transcription inhibitors and inflammatory cell activity

Inflammation is a central feature of asthma and chronic obstructive pulmonary disease (COPD). Despite recent advances in the knowledge of the pathogenesis of asthma and COPD, much more research on the molecular mechanisms of asthma and COPD are needed to aid the logical development of new therapies for these common and important diseases, particularly in COPD where no new effective treatments currently exist. In the future the role of the activation/repression of different transcription factors and the genetic regulation of their expression in asthma and COPD may be an increasingly important aspect of research, as this may be one of the critical mechanisms regulating the expression of different clinical phenotypes and their responsiveness to therapy, particularly to anti-inflammatory drugs.

Glucocorticoid Receptor Binding Inhibits an Intronic IL33 Enhancer and is Disrupted by rs4742170 (T) Allele Associated with Specific Wheezing Phenotype in Early Childhood

Interleukin 33 (IL-33) is a cytokine constitutively expressed by various cells of barrier tissues that contribute to the development of inflammatory immune responses. According to its function as an alarmin secreted by lung and airway epithelium, IL-33 plays a significant role in pathogenesis of allergic disorders. IL-33 is strongly involved in the pathogenesis of asthma, anaphylaxis, allergy and dermatitis, and genetic variations in IL33 locus are associated with increased susceptibility to asthma. Genome-wide association studies have identified risk "T" allele of the single-nucleotide polymorphism rs4742170 located in putative IL33 enhancer area as susceptible variant for development of specific wheezing phenotype in early childhood. Here, we demonstrate that risk "T" rs4742170 allele disrupts binding of glucocorticoid receptor (GR) transcription factor to IL33 putative enhancer. The IL33 promoter/enhancer constructs containing either 4742170 (T) allele or point mutations in the GR-binding site, were significantly more active and did not respond to cortisol in a pulmonary epithelial cell line. At the same time, the constructs containing rs4742170 (C) allele with a functional GR-binding site were less active and further inhibitable by cortisol. The latter effect was GR-dependent as it was completely abolished by GR-specific siRNA. This mechanism may explain the negative effect of the rs4742170 (T) risk allele on the development of wheezing phenotype that strongly correlates with allergic sensitization in childhood.

Effects of indole alkaloids from leaf of Alstonia scholaris on post-infectious cough in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Leaf of Alstonia scholaris (L.) R. Br. (Apocynaceae), a wide used ethic-medicine in many Asia and Africa counties, has also been recorded as the common traditional Chinese medicine for treatment of illnesses in respiratory system by Dai people.

AIM OF THE STUDY

To provide experimental data of clinical adaption of total indole alkaloids (TA) from leaf of A. scholaris for treating post-infectious cough in phase II clinical trial.

MATERIALS AND METHODS

To model post-infectious cough, all animals except control group were instilled intra-tracheal with lipopolysaccharide (LPS) (80 μg/50 µL/mouse), followed by subsequent exposure to cigarette smoke (CS) for 30 min per day for a total of 30 days. Mice were orally given TA at dose of 10, 25, 50 mg/kg, and four main alkaloids (Sch: scholaricine, Epi: 19-epischolaricine, Val: vallesamine, Pic: picrinine) once daily. Cellular infiltration was assessed in the broncho-alveolar lavage fluid (BALF). Expression of interleukin-6 (IL-6) and C-reactive protein (CRP) in the serum was determined, the superoxide dismutase (SOD) activity as well as malondialdehyde (MDA) content in the serum and homogenate were examined. Finally, histopathological examination in the lungs was assessed by H. E. staining.

RESULTS

After administration of TA and four major alkaloids respectively, the symptoms of cough in mice were obviously attenuated. Total white blood cells (WBC) and neutrophils (NEU) amounts in BALF were reduced obviously and the pathological damage of lung was also attenuated. There was also significant reduction in IL-6, CRP, MDA and a marked improvement in SOD.

CONCLUSIONS

The efficacy of indole alkaloids against post-infectious cough (PIC) was shown in the down-regulation of inflammatory cells, cytokines, and the balance of antioxidants. What's more, the pharmacological effects of TA were better than single indole alkaloid, which might be related to the synergic effect of four major alkaloids.

Corticosteroid insensitivity in smokers with asthma : clinical evidence, mechanisms, and management

Corticosteroids are the most effective treatment for asthma, but the therapeutic response varies considerably between individuals. Several clinical studies have found that smokers with asthma are insensitive to the beneficial effects of short- to medium-term inhaled corticosteroid treatment compared with non-smokers with asthma. It is estimated that 25% of adults in most industrialized countries smoke cigarettes, and similar surveys amongst asthmatic individuals suggest that the prevalence of smoking in this grouping mirrors that found in the general population. Therefore, cigarette smoking is probably the most common cause of corticosteroid insensitivity in asthma. Cigarette smoking and asthma are also associated with poor symptom control and an accelerated rate of decline in lung function. The mechanism of corticosteroid insensitivity in smokers with asthma is currently unexplained but could be due to alterations in airway inflammatory cell phenotypes, changes in glucocorticoid receptor alpha/beta ratio, and/or reduced histone deacetylase activity. Smoking cessation should be encouraged in all smokers with asthma. Short-term benefits include improvements in lung function and asthma control. However, the numbers of sustained quitters is disappointingly small. Additional or alternative drugs need to be identified to treat those individuals who are unable to stop smoking or who have persistent symptoms following smoking cessation.

Bitter taste receptors: Extraoral roles in pathophysiology

Over the past decade tremendous progress has been made in understanding the functional role of bitter taste receptors (T2Rs) and bitter taste perception. This review will cover the recent advances made in identifying the role of T2Rs in pathophysiological states. T2Rs are widely expressed in various parts of human anatomy and have been shown to be involved in physiology of respiratory system, gastrointestinal tract and endocrine system. Empirical evidence has shown T2Rs to be an integral component of antimicrobial immune responses in upper respiratory tract infections. The studies on human airway smooth muscle cells have shown that a potent bitter tastant induced bronchodilatory effects mediated by bitter taste receptors. Clinical data suggests a role for T2R38 polymorphism in predisposition of individuals to chronic rhinosinusitis. The role of genetic variation in T2Rs and its impact on disease susceptibility have been investigated in various other disease risk factors such as alcohol dependence, head and neck cancers. Preliminary reports have demonstrated differential expression of functional T2Rs in breast cancer cell lines. Studies on the role of T2Rs in pathophysiology of diseases including chronic rhinosinusitis, asthma, cystic fibrosis, and cancer have been promising. However, research in this field is in its nascent stages, and more confirmatory studies on animal models and in clinical settings are required.

Effect of total alkaloids from Alstonia scholaris on airway inflammation in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Alstonia scholaris (Apocynaceae) have been traditionally used for treatment of respiratory diseases in "dai" ethnopharmacy for hundreds years, especially for cough, asthma, phlegm, chronic obstructive pulmonary disease and so on. The formulas including the leaf extract have also been prescribed in hospitals and sold over the retail pharmacies.

AIM OF THE STUDY

A. scholaris is used as a traditional herbal medicine for the treatment of respiratory tract inflammation. However, there is no scientific evidence to validate the use of total alkaloids of A. scholaris in the literature. Here, we investigated the protective activity of total alkaloids (TA), extracted from the leaves of Alstonia scholaris, against lipopolysaccharide (LPS)-induced airway inflammation (AI) in rats.

MATERIALS AND METHODS

200 μg/μL LPS was instilled intratracheally in each rat, and then the modeling animals were divided into six groups (n=10, each) randomly: sham group, LPS group, Dexamethasone [1.5mg/kg, intra-gastricly (i.g.)] group, and three different doses (7.5, 15, and 30 mg/kg, i.g.) of total alkaloids-treated groups. Corresponding drugs or vehicles were orally administered once per day for 7 days consecutively. The concentration of albumin (ALB), alkaline phosphatase (AKP), lactate dehydrogenase (LDH), and the number of inflammatory cells in bronchoalveolar lavage fluid (BALF) were determined by fully automatic biochemical analyzer and blood counting instrument. Nitric oxide (NO) level, malondialdehyde (MDA) content, and superoxide dismutase (SOD) activities were examined by multiskan spectrum, and histological change in the lungs was analyzed by H.E. staining. The levels of inflammatory cytokine tumor necrosis factor-α (TNF-α) and interleukin-8 (IL-8) were measured using ELISA.

RESULTS

Total alkaloids decreased the percentage of neutrophil, number of WBC, levels of ALB, AKP and LDH in the BALF, while increased the content of ALB in serum. It also improved SOD activity and increased NO level in the lungs, serum and BALF, and reduced the concentration of MDA in the lungs. Total alkaloids also inhibited the production of inflammatory cytokines TNF-α and IL-8 in the BALF and lung. Finally, histopathological examination indicated that total alkaloids attenuated tissue injury of the lungs in LPS-induced AI.

CONCLUSIONS

Total alkaloids have an inhibitory effect against LPS-induced airway inflammation in rats.

Targeted anti-inflammatory therapeutics in asthma and chronic obstructive lung disease

Asthma and chronic obstructive pulmonary disease (COPD) are chronic inflammatory diseases of the airway, although the drivers and site of the inflammation differ between diseases. Asthmatics with a neutrophilic airway inflammation are associated with a poor response to corticosteroids, whereas asthmatics with eosinophilic inflammation respond better to corticosteroids. Biologicals targeting the Th2-eosinophil nexus such as anti-interleukin (IL)-4, anti-IL-5, and anti-IL-13 are ineffective in asthma as a whole but are more effective if patients are selected using cellular (eg, eosinophils) or molecular (eg, periostin) biomarkers. This highlights the key role of individual inflammatory mediators in driving the inflammatory response and for accurate disease phenotyping to allow greater understanding of disease and development of patient-oriented antiasthma therapies. In contrast to asthmatic patients, corticosteroids are relatively ineffective in COPD patients. Despite stratification of COPD patients, the results of targeted therapy have proved disappointing with the exception of recent studies using CXC chemokine receptor (CXCR)2 antagonists. Currently, several other novel mediator-targeted drugs are undergoing clinical trials. As with asthma specifically targeted treatments may be of most benefit in specific COPD patient endotypes. The use of novel inflammatory mediator-targeted therapeutic agents in selected patients with asthma or COPD and the detection of markers of responsiveness or nonresponsiveness will allow a link between clinical phenotypes and pathophysiological mechanisms to be delineated reaching the goal of endotyping patients.

Fluticasone furoate/vilanterol: a review of its use in chronic obstructive pulmonary disease

Fluticasone furoate/vilanterol (Relvar(®), Breo(®), Revinty(®)) is a fixed combination of a corticosteroid and a long-acting β2-adrenergic agonist (LABA) for once-daily use via a dry powder inhaler (Ellipta(®)). Fluticasone furoate/vilanterol 100/25 µg is approved for the treatment of chronic obstructive pulmonary disease (COPD) in several countries. This article reviews the clinical use of the combination in COPD and summarises pharmacological properties. Fluticasone furoate has enhanced affinity for the glucocorticoid receptor compared with other clinically used inhaled corticosteroids (ICS) and longer lung retention than fluticasone propionate. Vilanterol is highly selective for β2-adrenoreceptors and provides a rapid and prolonged duration of action. In phase 3 trials in patients with moderate to very severe COPD, overall, once-daily fluticasone furoate/vilanterol 100/25 µg improved pulmonary function more than placebo and fluticasone furoate alone and improved exacerbation rates more than vilanterol alone. With regard to pulmonary function, once-daily fluticasone furoate/vilanterol 100/25 μg was more effective than twice-daily fluticasone propionate/salmeterol 250/50 µg and similarly effective as twice-daily fluticasone propionate/salmeterol 500/50 μg. In 12-month trials, fluticasone furoate/vilanterol was generally well tolerated, and in 12- and 24-week trials, the incidence of adverse events was similar overall to that associated with the individual components or fluticasone propionate/salmeterol. However, as with the long-term use of all ICS agents, 12-month data indicate an increase in the risk of pneumonia with fluticasone furoate/vilanterol. In conclusion, fluticasone furoate/vilanterol is an effective and generally well tolerated additional LABA/ICS agent for the treatment of COPD with the added convenience of once-daily administration, which may improve treatment adherence in some patients.

Dynamic control of Th2 cell responses by STAT3 during allergic lung inflammation in mice

Signal transducer and activator of transcription (STAT) family molecules play essential roles during the differentiation of helper T cells from naïve precursors. Although the role of STAT3 in driving Th17 cell polarization has been well established, its role on Th2 responses to allergens remains incompletely understood. By employing T cell-specific STAT3 deficient mice, we demonstrate that STAT3 in T cells plays diverse role on Th2 cells depending on their locations in an animal model of allergic asthma. In the bronchial lymph nodes, STAT3-deficient T cells produced significantly reduced levels of Th2 cytokines. The frequencies of Th2 cells among CD4(+) T cells in the lung were comparable between STAT3-sufficient and STAT3-deficient T cells. By contrast, STAT3-deficient T cells in the airway exhibited significantly enhanced production of Th2 cell cytokines compared to STAT3-sufficient T cells. Interestingly, a major population of IL-4/5 producers among STAT3-deficient T cells in the airway co-produced IFNγ. The frequency of Th17 cells was significantly diminished whereas that of Th1 cells was increased in all the lung-associated tissues. Our results demonstrate the dynamic and opposing roles of STAT3 during the development of Th2 cells from bronchial lymph nodes to the airway and propose the need of careful consideration on STAT3-targeting approaches for the treatment of lung diseases.

Investigation into the mechanism of action of essential oil of Pistacia integerrima for its antiasthmatic activity

ETHNOPHARMACOLOGICAL RELEVANCE

Pistacia integerrima J.L. Stewart ex Brandis locally known as Karkatashringi is an important medicinal plant whose galls are valued in traditional medicine used in India for the treatment of asthma, chronic bronchitis, phthisis, diarrhea, fever, other ailments for the respiratory tract, and as antispasmodic, carminative, antiamoebic and anthelmintic. However, in vitro and in vivo investigations providing new insights into its pharmacological properties have not been thoroughly investigated yet. The present investigation aimed to elucidate the probable mechanism of antiasthmatic action of essential oil of Pistacia integerrima J.L. Stewart ex Brandis galls (EOPI).

METHODS

EOPI was tested using in vitro studies such as antioxidant activity, mast cell degranulation, angiogenesis, isolated guinea pig ileum preparation and soyabean lipoxidase enzyme activity. In vivo studies included lipopolysaccharide-induced bronchial inflammation in rats and airway hyperresponsiveness in ovalbumin in sensitized guinea pigs using spirometry.

RESULTS

EOPI (5-30 µg/ml) inhibits 5-lipoxidase enzyme activity with IC50 of 19.71 µg/ml and DPPH scavenging activity up to 100 µg/ml with maximum inhibition of 44.93 ± 2.53% at 100 µg/ml. Pre-treatment with EOPI inhibited erythropoietin-induced angiogenesis. It showed dose dependent (10, 30 and 100 µg/ml) anti-allergic activity by inhibiting compound 48/80 induced mast cell degranulation to an extent 19.08 ± 0.47%. The finding that essential oil induced inhibition of transient contraction of acetylcholine in calcium free medium, and relaxation of S-(-)-Bay 8644-precontracted isolated guinea pig ileum jointly suggests that the L-subtype Cav channel is involved in spasmolytic action of EOPI. Treatment with EOPI dose dependently (7.5, 15 and 30mg/kg i.p.) inhibited lipopolysaccharide-induced increase in total cell count, neutrophil count, nitrate-nitrite, total protein, albumin levels in bronchoalveolar fluid and myeloperoxidase levels in lung homogenates. Roflumilast was used as a standard. EOPI reduced the respiratory flow due to gasping in ovalbumin sensitized guinea pigs.

CONCLUSION

The study demonstrates the effectiveness of essential oil of Pistacia integerrima J.L. Stewart ex Brandis galls in bronchial asthma possibly related to its ability to inhibit L-subtype Cav channel, mast cell stabilization, antioxidant, angiostatic and through inhibition of 5-lipoxygenase enzyme.

Cytokine inhibition in the treatment of COPD

Cytokines play an important part in many pathobiological processes of chronic obstructive pulmonary disease (COPD), including the chronic inflammatory process, emphysema, and altered innate immune response. Proinflammatory cytokines of potential importance include tumor necrosis factor (TNF)-α, interferon-γ, interleukin (IL)-1β, IL-6, IL-17, IL-18, IL-32, and thymic stromal lymphopoietin (TSLP), and growth factors such as transforming growth factor-β. The current objectives of COPD treatment are to reduce symptoms, and to prevent and reduce the number of exacerbations. While current treatments achieve these goals to a certain extent, preventing the decline in lung function is not currently achievable. In addition, reversal of corticosteroid insensitivity and control of the fibrotic process while reducing the emphysematous process could also be controlled by specific cytokines. The abnormal pathobiological process of COPD may contribute to these fundamental characteristics of COPD, and therefore targeting cytokines involved may be a fruitful endeavor. Although there has been much work that has implicated various cytokines as potentially playing an important role in COPD, there have been very few studies that have examined the effect of specific cytokine blockade in COPD. The two largest studies that have been reported in the literature involve the use of blocking antibody to TNFα and CXCL8 (IL-8), and neither has provided benefit. Blocking the actions of CXCL8 through its CXCR2 receptor blockade was not successful either. Studies of antibodies against IL-17, IL-18, IL-1β, and TSLP are currently either being undertaken or planned. There is a need to carefully phenotype COPD and discover good biomarkers of drug efficacy for each specific target. Specific groups of COPD patients should be targeted with specific anticytokine therapy if there is evidence of high expression of that cytokine and there are features of the clinical expression of COPD that will respond.

Profile of fluticasone furoate/vilanterol dry powder inhaler combination therapy as a potential treatment for COPD

Currently, there is no cure for chronic obstructive pulmonary disease (COPD). The limited efficacy of current therapies for COPD indicates a pressing need to develop new treatments to prevent the progression of the disease, which consumes a significant amount of health care resources and is an important cause of mortality worldwide. Current national and international guidelines for the management of stable COPD patients recommend the use of inhaled long-acting bronchodilators, inhaled corticosteroids, and their combination for maintenance treatment of moderate to severe stable COPD. Once-daily fluticasone furoate/vilanterol dry powder inhaler combination therapy has recently been approved by the US Food and Drug Administration and the European Medicines Agency as a new regular treatment for patients with stable COPD. Fluticasone furoate/vilanterol dry powder inhaler combination therapy has been shown to be effective in many controlled clinical trials involving thousands of patients in the regular treatment of stable COPD. This is the first once-daily combination of ultra-long-acting inhaled β₂-agonists and inhaled glucocorticoids that is available for the treatment of stable COPD and has great potential to improve compliance to long-term regular inhaled therapy and hence to improve the natural history and prognosis of COPD patients.

A review on leukotrienes and their receptors with reference to asthma

OBJECTIVE AND METHODS

Leukotrienes (LTs) including cysteinyl leukotrienes (CysLTs) and LTB4 are the most potent inflammatory lipid mediators and play a central role in the pathophysiology of asthma and other inflammatory diseases. These biological molecules mediate a plethora of contractile and inflammatory responses through specific interaction with distinct G protein-coupled receptors (GPCRs). The main objective of this review is to present an overview of the biological effects of CysLTs and their receptors, along with the current knowledge of mechanisms and role of LTs in the pathogenesis of asthma.

RESULTS

CysLTs including LTC4, LTD4 and LTE4 are ligands for CysLT1 and CysLT2 receptors, and LTB4 is the agonist for BLT1 and BLT2 receptors. The role of CysLT1 receptor is well established, and most of the pathophysiological effects of CysLTs in asthma are mediated by CysLT1 receptor. Several CysLT1 antagonists have been developed to date and are currently in clinical practice. Most common among them are classical CysLT1 receptor antagonists such as montelukast, zafirlukast, pranlukast, pobilukast, iralukast, cinalukast and MK571. The pharmacological role of CysLT2 receptor, however, is less defined and there is no specific antagonist available so far. The recent demonstration that mice lacking both known CysLT receptors exhibit full/augmented response to CysLT points to the existence of additional subtypes of CysLT receptors. LTB4, on the other hand, is another potent inflammatory leukotriene, which acts as a strong chemoattractant for neutrophils, but weaker for eosinophils. LTB4 is known to play an important role in the development of airway hyper-responsiveness in severe asthma. However there is no LTB4 antagonist available in clinic to date.

CONCLUSION

This review gives a recent update on the LTs including their biosynthesis, biological effects and the role of anti-LTs in the treatment of asthma. It also discusses about the possible existence of additional subtypes of CysLT receptors.

Role of transcription factors in the pathogenesis of asthma and COPD

Inflammation is a central feature of asthma and chronic obstructive pulmonary disease (COPD). Despite recent advances in the knowledge of the pathogenesis of asthma and COPD, much more research on the molecular mechanisms of asthma and COPD are needed to aid the logical development of new therapies for these common and important diseases, particularly in COPD where no effective treatments currently exist. In the future the role of the activation/repression of different transcription factors and the genetic regulation of their expression in asthma and COPD may be an increasingly important aspect of research, as this may be one of the critical mechanisms regulating the expression of different clinical phenotypes and their responsiveness to therapy, particularly to anti-inflammatory drugs.

Anti-inflammatory effects of naringin in chronic pulmonary neutrophilic inflammation in cigarette smoke-exposed rats

Naringin, a well-known flavanone glycoside of grapefruit and citrus fruits, was found to be as an effective anti-inflammatory compound in our previous lipopolysaccharide-induced acute lung injury mouse model via blockading activity of nuclear factor κB. The current study sought to explore the anti-inflammatory effects of naringin on chronic pulmonary neutrophilic inflammation in cigarette smoke (CS)-induced rats. Seventy Sprague-Dawley rats were randomly divided into seven groups to study the effects of CS with or without various concentrations of naringin or saline for 8 weeks. The results revealed that naringin supplementation at 20, 40, and 80 mg/kg significantly increased body weight of CS-induced rats as compared to that in the CS group. Moreover, naringin of 20, 40, and 80 mg/kg prevented CS-induced infiltration of neutrophils and activation of myeloperoxidase and matrix metalloproteinase-9, in parallel with suppression of the release of cytokines, such as tumor necrosis factor-α and interleukin-8 (IL-8). IL-10 in bronchoalveolar lavage fluid was significantly suppressed after CS exposure, but dose dependently elevated by naringin. The results from hematoxylin and eosin staining revealed that naringin dose dependently reduced CS-induced infiltration of inflammatory cells, thickening of the bronchial wall, and expansion of average alveolar airspace. In conclusion, our data suggest that naringin is an effective anti-inflammatory compound for attenuating chronic pulmonary neutrophilic inflammation in CS-induced rats.

Glucocorticoid-induced leucine zipper is downregulated in human alveolar macrophages upon Toll-like receptor activation

Induction of the glucocorticoid-induced leucine zipper (GILZ) by glucocorticoids plays a role in their antiinflammatory action, whereas GILZ expression is reduced under inflammatory conditions. The mechanisms regulating GILZ expression during inflammation, however, have not yet been characterized. Here, we investigated GILZ expression in human alveolar macrophages (AMs) following Toll-like receptor (TLR) activation. Macrophages were shown to predominantly express GILZ transcript variant 2. Lipopolysaccharide-treated AMs, THP-1 cells, and lungs of lipopolysaccharide-exposed mice displayed decreased GILZ protein and mRNA levels. The effect was strictly dependent on the adapter molecule MyD88, as shown by using specific ligands or a knockdown strategy. Investigations on the functional significance of GILZ downregulation performed by GILZ knockdown revealed a proinflammatory response, as indicated by increased cytokine expression and NF-κB activity. We found that TLR activation reduced GILZ mRNA stability, which was mediated via the GILZ 3'-untranslated region. Finally, involvement of the mRNA-binding protein tristetraprolin (TTP) is suggested, since TTP overexpression or knockdown modulated GILZ expression and TTP was induced in a MyD88-dependent fashion. Taken together, our data show a MyD88- and TTP-dependent GILZ downreg-ulation in human macrophages upon TLR activation. Suppression of GILZ is mediated by mRNA destabilization, which might represent a regulatory mechanism in macrophage activation.

Association between single-nucleotide polymorphisms in interleukin-12A and risk of chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is characterized by airflow obstruction due to chronic bronchitis, emphysema, and/or disease of small airways. It has been reported that the genetic variation may play a role in the development and severity of COPD. The purpose of this study was to investigate whether single-nucleotide polymorphisms (SNP) in interleukin (IL)-12A and IL-12B were associated with COPD in a Chinese population. The IL-12A rs2243115 and IL-12B rs3212227 polymorphisms were genotyped by performing polymerase chain reaction-restriction fragment length polymorphism in 298 patients with COPD and 346 healthy controls. We observed that the frequencies of GT and GT+GG of IL-12A rs2243115 were significantly different from TT in the COPD group and the control group (GT vs. TT: odds ratio [OR]=2.35, 95% confidence interval [CI]=1.55-3.57, p<0.001; GT+GG vs. TT: OR=2.46, 95% CI=1.63-3.71, p<0.001). These data suggest that the IL-12A rs2243115 polymorphism may contribute to genetic susceptibility to COPD in a Chinese population.

Assessment of asthma and chronic obstructive pulmonary disorder in relation to reversibility, IgE, eosinophil, and neutrophil count in a University Teaching Hospital in South Delhi, India

Objectives:

The physiological and clinical similarities between asthma and chronic obstructive pulmonary disorder (COPD) make their differentiation difficult. In the present study, we compared reversibility to bronchodilator, immunoglobulin E (IgE), blood eosinophil and neutrophil levels among asthma and COPD patients to differentiate these diseases.

Materials and Methods:

The study was carried on 20 asthmatics and 29 patients of COPD that reported to the outpatient and inpatient department in University Teaching Hospital, Jamia Hamdard, New Delhi, India. The parameters evaluated included pulmonary function (FEV₁, FVC, and FEV₁/FVC), IgE levels, and eosinophil and neutrophil count.

Results:

It was observed that reversibility was significantly higher in asthmatic patients, while irreversibility predominates in COPD patients. There was no significant difference in pre- and post-FEV₁ and pre- and post-FVC and in their percentage predicted. However the percentage change in FEV₁ significantly varies in asthma and COPD patients. No significant changes in neutrophil and eosinophil levels were observed in these patients. The serum IgE levels were found significantly higher in asthmatic patients.

Conclusions:

We conclude that reversibility in FEV₁ levels or percentage change in FEV₁ and serum IgE levels are promising lab parameter to distinguish these two conditions. However, further research is required to fully understand the role of neutrophil and eosinophil in the onset and development of asthma and COPD.

Increased FKBP51 in induced sputum cells of chronic obstructive pulmonary disease patients after therapy

Objective

Immunophilin FKBP51 assists polypeptide folding, participates in glucocorticoid actions and may play a role in glucocorticoid resistance. FKBP51 is altered in patients with asthma, but its role in chronic obstructive pulmonary disease (COPD) characterized by dysregulation of several pro/antiinflammatory genes is less clear.

Methods

We assessed changes in nuclear/cytosolic FKBP51 protein using SDS-PAGE/WB and FKBP51 mRNA by qRT-PCR in cells isolated from induced sputum of stable COPD patients treated with formoterol/budesonide or formoterol/budesonide/theophylline for 4 wk.

Results

Expression of FKBP51 was higher in formoterol/budesonide/theophylline-treated patients, compared with formoterol/budesonide group in both cytosolic and nuclear fractions by about 57% and 31%, respectively (P < 0.001, P < 0.01). FKBP51 mRNA was only slightly, but not significantly, higher in patients on formoterol/budesonide/theophylline.

Conclusions

Increased FKBP51 in COPD patients treated with formoterol/budesonide/theophylline may be important in altering signaling from corticosteroid receptors.

Effect of Tanreqing Injection on treatment of acute exacerbation of chronic obstructive pulmonary disease with Chinese medicine syndrome of retention of phlegm and heat in Fei

OBJECTIVE

To explore the effect of Tanreqing Injection (TRQI) on the treatment of acute exacerbation of chronic obstructive pulmonary disease (AECOPD) with Chinese medicine syndrome of retention of phlegm and heat in Fei (RPHF).

METHODS

In a prospective randomized controlled clinical trial, 90 patients with AECOPD of RPHF syndrome were randomly assigned to 3 groups, TRQI and controls A and B, each with 30 cases. The TRQI group was administered with the intravenous injections of 20 mL TRQI once a day and conventional Western medicine treatment. Control group A was administered with the intravenous injection of 15 mg ambroxol hydrochloride twice a day and conventional Western medicine treatment, and control group B was administered with conventional Western medicine treatment only. The treatments were administered for 10 days. Chinese medical symptoms and signs were scored, and plasma concentrations of interleukin (IL)-8 and neutrophil elastase (NE) were recorded.

RESULTS

(1) The Chinese medical symptoms (cough, sputum amount, expectoration, dyspnea and fever) and signs (tongue and pulse) improved significantly in the TRQI group (P<0.05 or P<0.01), and improvements in cough, sputum amount and expectoration were better in the TRQI group than control group B (P<0.05); there was no significant difference between the TRQI group and control group A (P>0.05). The sign of tongue was also improved significantly in the TRQI group (P<0.05). (2) The overall effects in the TRQI group and control group A were significantly better than in control group B (P<0.05), with no significant differences between the TRQI group and control group A (P>0.05). There was no significant difference in the total effective rate among the three groups (P>0.05). (3) After treatment, the plasma concentrations of IL-8 and NE decreased in the TRQI group and control group A (P<0.05), and the concentration of IL-8 in control group B decreased (P<0.05). The difference in IL-8 was greater in the TRQI group than in control group A and B before and after treatment, and the change in NE was greater in control group A than in the TRQI group and control group B, but there was no statistical significance among the three groups with regards to the change in IL-8 or NE (P>0.05).

CONCLUSION

TRQI could improved the Chinese medical signs and symptoms in the patients with AECOPD, possibly because of the decreasing plasma levels of IL-8 and NE which could improve response to airway inflammation and mucus hypersecretion.

Nanomedicine for respiratory diseases

Treatment of respiratory diseases and infections has proved to be a challenging task, with the incidence of these ailments increasing worldwide. Nanotechnology-based drug and gene delivery systems offer a possible solution to some of the shortfalls of the current treatment regimen. Nanobased drug delivery systems have revolutionised the field of pharmacotherapy by presenting the ability to alter the pharmacokinetics of the conventional drugs to extend the drug retention time, reduce the toxicity and increase the half-life of the drugs. Delivery of exogenous genes to the airway epithelium in vivo has been limited by several physiological barriers, resulting in the low success rate of these systems. With the advent of nanotechnology, DNA compacted with cationic polymers to produce nanoparticles has exhibited a significant increase in the transfection efficiencies. With nanoparticulate drug/gene delivery systems, specific cells can be targeted by functionalising the polymeric nanoparticles with ligands that allow the particles to dock at a specific site of the cell. In addition, polymeric systems allow for the cargo to be released in a controlled and stimuli-responsive manner. The advantages that nanoparticulate delivery systems present in the treatment of respiratory diseases and infections are summarised in this review.

Effects of glucocorticoids on the neutrophil count: a cohort study among hospitalized patients

BACKGROUND

Systemic glucocorticoids are often used in clinical practice for a large variety of indications. Clinical observations have shown that patients using glucocorticoids often have higher neutrophil counts. Debate remains whether this observed neutrophilia is associated with glucocorticoid use or that other factors, like disease and severity of disease, should be considered. The objective of this study was to investigate the effect of systemic glucocorticoids on the absolute neutrophil count in hospitalized patients.

METHODS

A cohort study was conducted using data from the Utrecht Patient Oriented Database which comprises clinical data of patients of the University Medical Center Utrecht. We identified all adult patients, hospitalized in 2005 with at least two blood samples for hematological testing during admission and compared in-hospital glucocorticoid use with non-use.

RESULTS

A total of 809 glucocorticoid users and 2658 non-users were included in the study with comparable neutrophil counts at admission (8.2.10(9)/l for glucocorticoid users and 8.0.10(9)/l for non-users). Overall analysis showed a slight association between glucocorticoid use and an increase in neutrophil count (RR 1.3; 95% CI 1.1-1.5). However, within diagnostic subgroups there was no increase in neutrophil count in glucocorticoid users. Furthermore, among all no dose response relationship, no effect of time between the two samples, and no effect of anti-inflammatory/sodium retaining potency was found.

CONCLUSION

Observed neutrophilia in users of systemic glucocorticoids is probably associated with underlying disease, rather than glucocorticoid use itself.

New treatments for chronic obstructive pulmonary disease and viable formulation/device options for inhalation therapy

Chronic obstructive pulmonary disease (COPD) is an increasingly important cause of morbidity and mortality, pathological features of which are pulmonary inflammation and irreversible airflow obstruction. Current therapies for COPD are aimed at improvement of clinical symptoms and reduction of inflammation in the respiratory systems. There is a pressing need for the development of new COPD medication, particularly as no existing treatment has been shown to reduce disease progression. In spite of a better understanding of the underlying disease process, there have been limited advances in the drug therapy of COPD, in contrast to the enormous advances in asthma management. Several new therapeutic targets and strategies have been proposed, and new drug candidates, including bronchodilators, protease inhibitors anti-inflammatory drugs and mediator antagonists, are now in clinical development for COPD treatment. New dry powder inhaler (DPI) systems for inhaled COPD therapy have also been developed to maximize drug concentrations in the airway systems, while minimizing systemic exposure and associated toxicity. This article aims to review recent developments in COPD drugs and the delivery systems for inhalation therapy, with particular emphasis on device options and formulations of DPI systems.

Effects of intratracheal administration of nuclear factor-kappaB decoy oligodeoxynucleotides on long-term cigarette smoke-induced lung inflammation and pathology in mice

To determine if nuclear factor-kappaB (NF-kappaB) activation may be a key factor in lung inflammation and respiratory dysfunction, we investigated whether NF-kappaB can be blocked by intratracheal administration of NF-kappaB decoy oligodeoxynucleotides (ODNs), and whether decoy ODN-mediated NF-kappaB inhibition can prevent smoke-induced lung inflammation, respiratory dysfunction, and improve pathological alteration in the small airways and lung parenchyma in the long-term smoke-induced mouse model system. We also detected changes in transcriptional factors. In vivo, the transfection efficiency of NF-kappaB decoy ODNs to alveolar macrophages in BALF was measured by fluorescein isothiocyanate (FITC)-labeled NF-kappaB decoy ODNs and flow cytometry post intratracheal ODN administration. Pulmonary function was measured by pressure sensors, and pathological changes were assessed using histology and the pathological Mias software. NF-kappaB and activator protein 1(AP-1) activity was detected by the electrophoretic motility shift assay (EMSA). Mouse cytokine and chemokine pulmonary expression profiles were investigated by enzyme-linked immunosorbent assay (ELISA) in bronchoalveolar lavage fluid (BALF) and lung tissue homogenates, respectively, after repeated exposure to cigarette smoke. After 24 h, the percentage of transfected alveolar macrophages was 30.00 +/- 3.30%. Analysis of respiratory function indicated that transfection of NF-kappaB decoy ODNs significantly impacted peak expiratory flow (PEF), and bronchoalveolar lavage cytology displayed evidence of decreased macrophage infiltration in airways compared to normal saline-treated or scramble NF-kappaB decoy ODNs smoke exposed mice. NF-kappaB decoy ODNs inhibited significantly level of macrophage inflammatory protein (MIP) 1alpha and monocyte chemoattractant protein 1(MCP-1) in lung homogenates compared to normal saline-treated smoke exposed mice. In contrast, these NF-kappaB decoy ODNs-treated mice showed significant increase in the level of tumor necrosis factor-alpha(TNF-alpha) and pro-MMP-9(pro-matrix metalloproteinase-9) in mice BALF. Further measurement revealed administration of NF-kappaB decoy ODNs did not prevent pathological changes. These findings indicate that NF-kappaB activation play an important role on the recruitment of macrophages and pulmonary dysfunction in smoke-induced chronic lung inflammation, and with the exception of NF-kappaB pathway, there might be complex mechanism governing molecular dynamics of pro-inflammatory cytokines expression and structural changes in small airways and pulmonary parenchyma in vivo.

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

BACKGROUND

Bronchial asthma is characterized by lower airway inflammation and remodelling. Anti-inflammatory treatment with inhaled corticosteroids (ICS) provides the mainstay of asthma therapy together with bronchodilation induced by short- and long-acting inhaled beta(2)-agonists. Lower airway fibroblasts may play a critical role in airway inflammation and remodelling, suggesting that they might represent an important target for the major anti-asthmatic drugs. The aim of our study was to investigate the effects of beclomethasone dipropionate (BDP), salbutamol and formoterol either alone or in combination on in vitro cultures of human bronchial fibroblasts.

METHODS

Fibroblasts were cultured in the presence of pro-inflammatory and proliferative stimuli, BDP, salbutamol and formoterol. The effects of drugs on cell proliferation were ascertained by (3)H-thymidine incorporation. CD90 and CD44 expression were detected by flow cytometry and fibronectin secretion using the enzyme-linked immunosorbent assay technique.

RESULTS

This study showed that BDP alone has significant anti-proliferative effects on lung fibroblasts treated with basic fibroblast growth factor and the combination of BDP with formoterol or salbutamol strengthen these effects. Short-acting beta(2)-agonist (SABA) or long-acting beta(2)-agonist (LABA) by themselves did not show any significant effect on the different cultures. CD44 and CD90 expression and fibronectin production were modulated by pro-inflammatory and proliferative stimuli; the addition of the drugs brought them back near to the basal level.

CONCLUSIONS

From this in vitro study, we can conclude that BDP, when combined with salbutamol or formoterol, exhibits enhanced anti-remodelling activity in bronchial fibroblasts, providing new insights on the additive effects of ICS and SABAs and LABAs for asthma therapy.

Glycyrrhizin inhibits interleukin-8 production and nuclear factor-kappaB activity in lung epithelial cells, but not through glucocorticoid receptors

This study was designed to examine the glucocorticoid-like inhibitory effect of glycyrrhizin (GL) on interleukin (IL)-8 production in A549 lung epithelial cells. GL, as well as dexamethasone (DEX) inhibited both tumor necrosis factor (TNF)-α –and IL-1β –induced IL-8 production, mRNA expression, and promoter activity in A549 cells. Both GL and DEX inhibited transactivation of nuclear factor (NF)-κ B, without inhibiting translocation of the NF-κ B p65 subunit to the nucleus. However, the effect of GL was insensitive to RU486, a GR antagonist, and to GR knockdown by siRNA. Furthermore, only GL inhibited DNA binding of p65 to the IL-8 promoter region. These findings indicated that GL had a glucocorticoid-like inhibitory effect on IL-8 production via a mechanism that differs from that of glucocorticoids.

New drugs targeting Th2 lymphocytes in asthma

Asthma represents a profound worldwide public health problem. The most effective anti-asthmatic drugs currently available include inhaled beta2-agonists and glucocorticoids and control asthma in about 90-95% of patients. The current asthma therapies are not cures and symptoms return soon after treatment is stopped even after long term therapy. Although glucocorticoids are highly effective in controlling the inflammatory process in asthma, they appear to have little effect on the lower airway remodelling processes that appear to play a role in the pathophysiology of asthma at currently prescribed doses. The development of novel drugs may allow resolution of these changes. In addition, severe glucocorticoid-dependent and resistant asthma presents a great clinical burden and reducing the side-effects of glucocorticoids using novel steroid-sparing agents is needed. Furthermore, the mechanisms involved in the persistence of inflammation are poorly understood and the reasons why some patients have severe life threatening asthma and others have very mild disease are still unknown. Drug development for asthma has been directed at improving currently available drugs and findings new compounds that usually target the Th2-driven airway inflammatory response. Considering the apparently central role of T lymphocytes in the pathogenesis of asthma, drugs targeting disease-inducing Th2 cells are promising therapeutic strategies. However, although animal models of asthma suggest that this is feasible, the translation of these types of studies for the treatment of human asthma remains poor due to the limitations of the models currently used. The myriad of new compounds that are in development directed to modulate Th2 cells recruitment and/or activation will clarify in the near future the relative importance of these cells and their mediators in the complex interactions with the other pro-inflammatory/anti-inflammatory cells and mediators responsible of the different asthmatic phenotypes. Some of these new Th2-oriented strategies may in the future not only control symptoms and modify the natural course of asthma, but also potentially prevent or cure the disease.

Role of macrolide therapy in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a leading cause of death and disability worldwide. The Global Burden of Disease study has concluded that COPD will become the third leading cause of death worldwide by 2020, and will increase its ranking of disability-adjusted life years lost from 12th to 5th. Acute exacerbations of COPD (AECOPD) are associated with impaired quality of life and pulmonary function. More frequent or severe AECOPDs have been associated with especially markedly impaired quality of life and a greater longitudinal loss of pulmonary function. COPD and AECOPDs are characterized by an augmented inflammatory response. Macrolide antibiotics are macrocyclical lactones that provide adequate coverage for the most frequently identified pathogens in AECOPD and have been generally included in published guidelines for AECOPD management. In addition, they exert broad-ranging, immunomodulatory effects both in vitro and in vivo, as well as diverse actions that suppress microbial virulence factors. Macrolide antibiotics have been used to successfully treat a number of chronic, inflammatory lung disorders including diffuse panbronchiolitis, asthma, noncystic fibrosis associated bronchiectasis, and cystic fibrosis. Data in COPD patients have been limited and contradictory but the majority hint to a potential clinical and biological effect. Additional, prospective, controlled data are required to define any potential treatment effect, the nature of this effect, and the role of bronchiectasis, baseline colonization, and other cormorbidities.

Bioactive analogues and drug delivery systems of vasoactive intestinal peptide (VIP) for the treatment of asthma/COPD

Vasoactive intestinal peptide (VIP) is one of the major peptide transmitters in the central and peripheral nervous systems, being involved in a wide range of biological functions. In an airway system where VIP-immunoreactive nerve fibers are present, VIP acts as neurotransmitter or neuromodulator of the inhibitory non-adrenergic and non-cholinergic airway nervous system and influences many aspects of pulmonary biology. A clinical application of VIP has been believed to offer potential benefits in the treatment of chronic inflammatory lung diseases such as asthma and chronic obstructive pulmonary disease (COPD), however, its clinical application has been limited in the past for a number of reasons, including its extremely short plasma half-life after intravenous administration and difficulty in administration routes. The development of long-acting VIP analogues, in combination with appropriate drug delivery systems, may provide clinically useful agents for the treatment of asthma/COPD. In this review, development of efficacious VIP derivatives, drug delivery systems designed for VIPs and the potential application for asthma/COPD are discussed. We also include original data from our chemical modification experiments and formulation studies, which led to successful development of [R(15, 20, 21), L(17)]-VIP-GRR (IK312532), a potent VIP analogue, and a VIPs-based dry powder inhaler system.

Impact of protein acetylation in inflammatory lung diseases

Chronic inflammatory lung diseases are characterized by increased expression of multiple inflammatory genes following activation by proinflammatory transcription factors, such as nuclear factor kappaB (NF-kappaB) and AP-1. Gene expression is, at least in part, regulated by acetylation of core histones through the action of coactivators, such as CREB-binding protein (CBP), which have intrinsic histone acetyltransferase (HAT) activity. Conversely gene repression is mediated via a combination of histone deacetylases (HDAC) and other corepressors. In asthma, the level of HAT activity is elevated in bronchial biopsies, whereas HDAC activity levels are only partially reduced and inhaled corticosteroids are able to reduce the increased HAT activity back to those seen in normal subjects. In contrast, in chronic obstructive pulmonary disease (COPD), there is a greater reduction in HDAC activity and HDAC2 expression but no difference in HAT activity. HAT and HDAC are also reported to modify a large and expanding number of nonhistone proteins, including nuclear import proteins, chaperones, cytoskeletal proteins, and other transcriptional factors, such as NF-kappaB and signal transducer and activation of transcription (STAT). Acetylation regulates several aspects of protein function and stability leading to differing effects on inflammatory gene expression and cell recruitment involved in the pathogenesis of inflammatory diseases. This review will examine the impact of acetylation on the function of key proteins involved in airway inflammatory disease and the effects of current therapies on acetylation status of key proteins. Further appreciation of the role of these changes may lead to the development of novel therapeutic approaches to inflammatory lung diseases that are currently difficult to treat.

Gene–environment interactions in the development of chronic obstructive pulmonary disease

PURPOSE OF REVIEW

Genetic factors influence the variable development of chronic obstructive pulmonary disease in response to smoking and are likely to vary between populations. Recent studies have begun to shed some light on these gene-environment interactions.

RECENT FINDINGS

A variety of approaches has been used to identify novel susceptibility genes for chronic obstructive pulmonary disease. These studies have provided evidence for the possible role of many inflammatory mediators and their receptors, proteases, antiproteases, and antioxidant and xenobiotic genes in chronic obstructive pulmonary disease pathophysiology. However, ethnic differences and subtle phenotype differences often make replication of these studies difficult.

SUMMARY

The completion of the Human Genome Project, the HapMap project, technological advances in single-nucleotide-polymorphism genotyping and the potential of genome-wide association analysis will allow the identification of susceptibility genes for chronic obstructive pulmonary disease. The challenge is to understand the influence of multiple genetic factors and multiple environmental factors as well as gene-gene and gene-environment interactions. Careful clinical characterization of phenotypes for chronic obstructive pulmonary disease is essential and this will include comparison of biomarkers of distinct pathologies including radiological assessment to separate the components of pulmonary emphysema and small-airway disease.

Roflumilast, a phosphodiesterase 4 inhibitor, reduces airway hyperresponsiveness after allergen challenge

BACKGROUND

Roflumilast, an oral, once-daily phosphodiesterase 4 inhibitor, is currently in clinical development for the treatment of asthma.

OBJECTIVES

This pilot study examined the effect of roflumilast on allergen-induced airway hyperresponsiveness (AHR) to histamine challenge and asthmatic response to allergen challenge.

METHODS

In a randomized, double-blind, 2-period, crossover trial, 13 patients with mild allergic asthma [mean forced expiratory volume in 1 s (FEV(1)) % predicted = 86%] received a single dose of oral roflumilast 1,000 microg or placebo. Patients were administered roflumilast 60 min before allergen challenge, and asthmatic responses were assessed via change in FEV(1) <or=9 h after allergen challenge. AHR to histamine provocation was measured before and repeated 24 h after allergen provocation. Patients inhaled histamine in doubling concentrations until attaining a decrease in FEV(1) of <or=20% (PC(20)FEV(1)).

RESULTS

Roflumilast had no detectable bronchodilator activity 60 min after administration. Roflumilast significantly attenuated AHR compared with placebo, with a mean change in pre- to postallergen challenge PC(20)FEV(1) ratio of 1.23 +/- 2.75 and 2.51 +/- 2.95 for roflumilast and placebo, respectively (p = 0.002). During the late asthmatic response, roflumilast reduced the mean maximum decrease in FEV(1) from 2 to 9 h after allergen challenge compared with placebo (p = 0.005). Additionally, FEV(1) at 9 h after challenge was significantly higher in patients treated with roflumilast (p = 0.03). Early asthmatic responses to allergen challenge were not significantly reduced by the single dose of roflumilast.

CONCLUSIONS

Roflumilast attenuated allergen-induced AHR in patients with mild asthma. These results support further investigation of roflumilast as an anti-inflammatory treatment of asthma.

Inhibition of proinflammatory tumor necrosis factor-{alpha}-induced inducible nitric-oxide synthase by xanthine-based 7-[2-[4-(2-chlorobenzene)piperazinyl]ethyl]-1,3-dimethylxanthine (KMUP-1) and 7-[2-[4-(4-nitrobenzene)piperazinyl]ethyl]-1, 3-dimethylxanthine (KMUP-3) in rat trachea: The involvement of soluble guanylate cyclase and protein kinase G

In the study of anti-proinflammation by 7-[2-[4-(2-chlorobenzene)piperazinyl] ethyl]-1,3-dimethylxanthine (KMUP-1) and 7-[2-[4-(4-nitrobenzene)piperazinyl]ethyl]-1,3-dimethylxanthine (KMUP-3), exposure of rat tracheal smooth muscle cells (TSMCs) to tumor necrosis factor-alpha (TNF-alpha), a proinflammatory cytokine, increased the expression of inducible nitric-oxide synthase (iNOS) and NO production and decreased the expression of soluble guanylate cyclase alpha1 (sGCalpha1), soluble guanylate cyclase beta1 (sGCbeta1), protein kinase G (PKG), and the release of cGMP in TSMCs. The cell-permeable cGMP analog 8-Br-cGMP, xanthine-based KMUP-1 and KMUP-3, and the phosphodiesterase 5 inhibitor zaprinast all inhibited TNF-alpha-induced increases of iNOS expression and NO levels and reversed TNF-alpha-induced decreases of sGCalpha1, sGCbeta1, and PKG expression. These results imply that cGMP enhancers could have anti-proinflammatory potential in TSMCs. TNF-alpha also increased protein kinase A (PKA) expression and cAMP levels, cyclooxygenase-2 (COX-2) expression, and activated productions of prostaglandin (PG) E2 and 6-keto-PGF1alpha (stable PGI2 metabolite). Dexamethasone and N-[2-(cyclohexyloxyl)-4-nitrophenyl]-methane sulfonamide (NS-398; a selective COX-2 inhibitor) attenuated TNF-alpha-induced expression of COX-2 and activated productions PGE2 and PGI2. However, KMUP-1 and KMUP-3 did not affect COX-2 activities and did not further enhance cAMP levels in the presence of TNF-alpha. It is suggested that TNF-alpha-induced increases of PKA expression and cAMP levels are mediated by releasing PGE2 and PGI2, the activation products of COX-2. In conclusion, xanthine-based KMUP-1 and KMUP-3 inhibit TNF-alpha-induced expression of iNOS in TSMCs, involving the sGC/cGMP/PKG expression pathway but without the involvement of COX-2.

Does the combination of inhaled steroids with long acting beta2 agonists decrease the risk for osteoporosis? A 1-year prospective follow-up study

Combination of inhaled corticosteroids (ICS) with long acting beta2 agonists has been used increasingly in the treatment of moderate-severe asthma, however there is indefinitive data about their effect on bone loss. The aim of this study was to compare the effects of treatment with single ICS and combination of ICS with long acting beta2 agonists (combination therapy) on BMD and biomarkers of bone metabolism in adult patients with asthma over 1 year period. Forty-three patients with asthma were enrolled. Patients were separated into two groups according to their use of asthma drugs: single ICS or combination therapy (ICS plus long-acting inhaled beta2-agonist). Change in bone mineral density (BMD) and biochemical markers of bone metabolism were measured at baseline and at the end of 1 year. Mean ages and basal BMD of patients did not differ between the two groups (P > 0.05). The decrease in BMD was higher in the single ICS group than the combination therapy group, however there was no significant difference between them (P > 0.05). One year change (%) in BMD and biochemical markers of bone metabolism were not different between two groups (P > 0.05). In conclusion, use of ICS-in the range of doses used- does not seem to have an effect on the change of BMD. However, our data indicate a nonsignificant trend towards reducing bone loss with the use of combination therapy. Future studies are needed to provide definitive evidence for this trend to allow us suggesting combination therapy for minimizing bone loss.

Thiolated chitosan nanoparticles enhance anti-inflammatory effects of intranasally delivered theophylline

Background

Chitosan, a polymer derived from chitin, has been used for nasal drug delivery because of its biocompatibility, biodegradability and bioadhesiveness. Theophylline is a drug that reduces the inflammatory effects of allergic asthma but is difficult to administer at an appropriate dosage without causing adverse side effects. It was hypothesized that adsorption of theophylline to chitosan nanoparticles modified by the addition of thiol groups would improve theophylline absorption by the bronchial epithelium and enhance its anti-inflammatory effects.

Objectives

We sought to develop an improved drug-delivery matrix for theophylline based on thiolated chitosan, and to investigate whether thiolated chitosan nanoparticles (TCNs) can enhance theophylline's capacity to alleviate allergic asthma.

Methods

A mouse model of allergic asthma was used to test the effects of theophylline in vivo. BALB/c mice were sensitized to ovalbumin (OVA) and OVA-challenged to produce an inflammatory allergic condition. They were then treated intranasally with theophylline alone, chitosan nanoparticles alone or theophylline adsorbed to TCNs. The effects of theophylline on cellular infiltration in bronchoalveolar lavage (BAL) fluid, histopathology of lung sections, and apoptosis of lung cells were investigated to determine the effectiveness of TCNs as a drug-delivery vehicle for theophylline.

Results

Theophylline alone exerts a moderate anti-inflammatory effect, as evidenced by the decrease in eosinophils in BAL fluid, the reduction of bronchial damage, inhibition of mucus hypersecretion and increased apoptosis of lung cells. The effects of theophylline were significantly enhanced when the drug was delivered by TCNs.

Conclusion

Intranasal delivery of theophylline complexed with TCNs augmented the anti-inflammatory effects of the drug compared to theophylline administered alone in a mouse model of allergic asthma. The beneficial effects of theophylline in treating asthma may be enhanced through the use of this novel drug delivery system.

Strategies for targeting T-cells in allergic diseases and asthma

T helper (Th) 2 lymphocytes play a crucial role in the initiation, progression and persistence of allergic diseases, including asthma. Drugs that interfere with the activation of T-cells or more selectively Th2-specific signaling molecules and drugs that prevent the selective migration into lung tissue are promising novel strategies for the treatment of allergic asthma. Although the mainstay asthma therapy of inhaled glucocorticoids is rather effective, targeting Th2 cells may be an important alternative in childhood. Regulatory T-cells (Treg cells) have a physiological role in protection of unwanted immune responses to auto-antigens and allergens. Literature data indicate that an imbalance between Th2 and Treg cells may underlie development and disease expression of allergic asthma. Drugs or immunotherapies that stimulate these counter-Treg cells may limit aberrant Th2 responses leading to suppression of symptoms. Furthermore, these types of treatments may offer the perspective of disease modification and long-term relief of symptoms.

Efficacy and safety of roflumilast in the treatment of asthma

BACKGROUND

The central role of chronic inflammation of the airways in asthma pathogenesis is supported by the efficacy of corticosteroids in controlling clinical symptoms. However, the search continues for potentially safer anti-inflammatory alternatives. Roflumilast is an oral, once-daily phosphodiesterase type 4 inhibitor with anti-inflammatory activity in preclinical models of asthma and chronic obstructive pulmonary disease.

OBJECTIVE

To investigate the dose-ranging efficacy and safety of roflumilast in patients with mild-to-moderate asthma.

METHODS

Patients (N = 693) were randomized in a double-blind, parallel-group, phase 2/3 study. After a 1- to 3-week placebo run-in period, patients (mean forced expiratory volume in 1 second [FEV1], 73% of predicted) were randomized to receive 100, 250, or 500 microg of roflumilast once daily for 12 weeks. The primary end point was change from baseline in FEV1; secondary end points included change from baseline in morning and evening peak expiratory flow.

RESULTS

Roflumilast use significantly increased FEV1 (P < .001 vs baseline). Improvements from baseline in FEV1 at the last visit were 260, 320, and 400 mL for the 100-, 250-, and 500-microg dose groups, respectively. Roflumilast, 500 microg, was superior to roflumilast, 100 microg, by 140 mL in improving FEV1 (P = .002). There were also significant improvements from baseline in morning and evening peak expiratory flow in all the dose groups (P < or = .006). Roflumilast was well tolerated at all doses tested. Most adverse events were mild to moderate in intensity and transient.

CONCLUSION

These results support the emerging role of roflumilast, 500 microg/d, in the treatment of asthma.

Chronic obstructive pulmonary disease: histopathology, inflammation and potential therapies

Chronic obstructive pulmonary disease (COPD) is a major worldwide health burden with increasing morbidity, mortality and health care cost. It is a slowly progressive chronic inflammatory condition that affects the conducting airways (both large and small) and lung parenchyma. In COPD, inflammation is evident early on even in mild disease and increases with disease severity. Recent advances in our knowledge demonstrate, by comparison with asthma, the distinctive, "abnormal" or exaggerated inflammatory processes involved in the pathogenesis of COPD and thus identify novel therapeutic targets that could potentially impact on disease progression. The present review will focus on what is known of the abnormal inflammatory response of COPD in different regions of the conducting airways and lung. Novel, potentially promising approaches to therapy are presented.

Roflumilast inhibition of pulmonary leukotriene production and bronchoconstriction in ovalbumin-sensitized and -challenged Guinea pigs

This study investigated the effects of roflumilast, a PDE4 inhibitor, on slow-reacting substance of anaphylaxis (SRS-A)-mediated bronchoconstriction and pulmonary leukotriene (LT) release in ovalbumin (OVA)-sensitized and -challenged guinea pigs. Animals were treated with roflumilast orally (0.04, 0.12, 0.4, or 4 mg/kg) or placebo 1 hour before OVA challenge. Bronchoconstriction was quantified by measuring airway conductance (Gaw) and dynamic lung compliance (Cdyn). Roflumilast significantly attenuated the decrease in Gaw (50% inhibitory dose [ID50] = 0.33 mg/kg) and Cdyn (ID50 = 0.25 mg/kg) in a dose-dependent manner and significantly inhibited Cys-LT (ID50 = 0.06 mg/kg) and LTB4 (ID50 = 0.05 mg/kg) release versus placebo-treated animals. Roflumilast did not affect LTD4-induced bronchoconstriction. These findings support the role of roflumilast as an anti-inflammatory treatment for asthma.

Kinase inhibitors and airway inflammation

Kinases are believed to play a crucial role in the expression and activation of inflammatory mediators in the airway, in T-cell function and airway remodelling. Important kinases such as Inhibitor of kappaB kinase (IKK)2, mitogen activated protein (MAP) kinases and phsopho-inositol (PI)3 kinase regulate inflammation either through activation of pro-inflammatory transcription factors such as activating protein-1 (AP-1) and nuclear factor kappaB (NF-kappaB), which are activated in airway disease, or through regulation of mRNA half-life. Selective kinase inhibitors have been developed which reduce inflammation and some characteristics of disease in animal models. Targeting specific kinases that are overexpressed or over active in disease should allow for selective treatment of respiratory diseases. Interest in this area has intensified due to the success of the specific Abelson murine leukaemia viral oncogene (Abl) kinase inhibitor imatinib mesylate (Gleevec) in the treatment of chronic myelogenous leukaemia. Encouraging data from animal models and primary cells and early Phase I and II studies in other diseases suggest that inhibitors of p38 MAP kinase and IKK2 may prove to be useful novel therapies in the treatment of severe asthma, chronic obstructive pulmonary disease (COPD), cystic fibrosis and other inflammatory airway diseases.