Novel drugs for treating asthma

Pharmacokinetics and safety evaluation in healthy Chinese volunteers of alkaloids from leaf of Alstonia scholaris: A multiple doses phase I clinical trial

BACKGROUND

Alstonia scholaris (Apocynaceae) was reported to be a rich source of indole alkaloids, which exhibited remarkably bioactivities. The leaf of A. scholaris has been used in 'dai' ethno-medicine for treatment of respiratory diseases, and the defined indole alkaloids from leaf of A. scholaris has been registered as investigational new botanical drug (No. 2011L01436) and was approved for phase I/II clinical trials by China Food and Drug Administration (CFDA).

PURPOSE

The aim of the trial is to evaluate the safety and explore the relationship of dosing frequency and pharmacokinetics after oral administration of capsule of alkaloids from leaf of A. scholaris (CALAS) at different doses.

METHODS

In this randomized, open-labelled, single-center clinical trial, the safety and pharmacokinetics of CALAS were assessed in eligible healthy Chinese volunteers after oral administration of different doses. Each volunteer (n = 10 per group) received single dose of CALAS from 20 mg, 40 mg, 80 mg to 120 mg orally. The pharmacokinetics of CALAS was investigated in healthy Chinese subjects' plasma by a fully-validated LC-MS/MS method. Safety was assessed biochemically and clinically throughout the study, and drug re-excitation research was conducted to verify the correlation between investigational product and minor adverse events. The trial was registered on August 26, 2015 (http://www.chictr.org.cn/showproj.aspx?proj=11736), number ChiCTR-IPR-15006976.

RESULTS

40 subjects completed the study, and as a result, vallesamine had the highest concentration in plasma of healthy volunteers, and the AUC exposure level in each compounds in turn is vallesamine > scholaricine > 19-epischolaricine > picrinine. For the safety evaluation of CALAS, two cases of minor adverse events were observed during the trial, but the drug re-excitation research indicated that these two adverse events were related to the individual's physiological variation.

CONCLUSION

Pharmacokinetic characteristics of each ingredient showed different patterns. 19-epischolaricine, vallesamine and picrinine were match to the linear pharmacokinetic characteristics, but scholaricine conformed to the characteristics of nonlinear pharmacokinetics. The CALAS was safe in healthy subjects under the current dose regimen.

Comparing the effects of fluticasone, anti-IgE and anti-TNF treatments in a chronic asthma model

BACKGROUND

Corticosteroids are used in the treatment of asthma. The aim of this study was to determine the efficacy of anti-IgE and anti-TNF alpha as asthma treatments.

METHODS

A mouse model of chronic asthma was developed. The fluticasone group was exposed to fluticasone and the anti-IgE and anti-TNF groups were administered anti-IgE or anti-TNF. IL-4, and IgE levels were measured, and histological analysis, pathological analysis and miRNA-126, miRNA-133a analyses were applied.

RESULTS

The cell concentration in the BAL fluid decreased in all the treatment groups. The rate of perivascular and peribronchial cell infiltration decreased in the lung in the high-dose anti-IgE and anti-TNF groups. Smooth muscle thickness decreased in the lung tissue in the low-dose anti-IgE and anti-TNF groups. Bronchial wall thickness decreased in the lung tissue in the fluticasone+anti-IgE group. The IL-4 level in BAL fluid decreased in the high-dose anti-IgE, fluticasone+anti-IgE and anti-TNF groups. IgE levels increased in the BAL fluid in the high-dose anti-IgE and anti-TNF groups. The lymphocyte level increased in the BAL fluid in the high-dose anti-IgE group. The macrophage level decreased in the BAL fluid in the anti-TNF group. The relative expression of miRNA-126 increased in all groups. The relative expression of miRNA-133a decreased in the placebo and fluticasone groups. The relative expression of miRNA-133a increased in the low-dose anti-IgE, high-dose anti-IgE, fluticasone+anti-IgE and anti-TNF groups.

CONCLUSIONS

The results showed that anti-IgE is successful as a treatment. Fluticasone+anti-IgE and anti-TNF were seen to be superior to other therapeutic modalities when used for prophylaxis.

Chemokines and Their Receptors in Islet Allograft Rejection and as Targets for Tolerance Induction

Graft rejection is a major barrier to successful outcome of transplantation surgery. Islet transplantation introduces insulin secreting tissue into type 1 diabetes mellitus recipients, relieving patients from exogenous insulin injection. However, insulitis of grafted tissue and allograft rejection prevent long-term insulin independence. Leukocyte trafficking is necessary for the launch of successful immune responses to pathogen or allograft. Chemokines, small chemotactic cytokines, direct the migration of leukocytes through their interaction with chemokine receptors found on cell surfaces of immune cells. Unique receptor expression of leukocytes, and the specificity of chemokine secretion during various states of immune response, suggest that the extracellular chemokine milieu specifically homes certain leukocyte subsets. Thus, only those leukocytes required for the current immune task are attracted to the inflammatory site. Chemokine blockade, using antagonists and monoclonal antibodies directed against chemokine receptors, is an emerging and specific immunosuppressive strategy. Importantly, chemokine blockade may potentiate tolerance induction regimens to be used following transplantation surgery, and prevent the need for life-long immunosuppression of islet transplant recipients. Here, the role for chemokine blockade in islet transplant rejection and tolerance is reviewed.

Airways antiallergic effect and pharmacokinetics of alkaloids from Alstonia scholaris

BACKGROUND

Alstonia scholaris (L.) R. Br. (Apocynaceae), an important herbal medicine, has been widely used to treat respiratory tract diseases, such as cough, asthma, phlegm, and chronic obstructive pulmonary disease.

PURPOSE

To evaluate pharmacological effect of alkaloids from A. scholaris on ovalbumin induced airways allergic inflammatory model, and explore whether the dosing frequency is related to pharmacokinetics.

STUDY DESIGN

After oral administration of total alkaloids, the pharmacokinetic study of it was investigated. In addition, anti-allergic studies were carried out on ovalbumin-sensitized airways allergic inflammatory model of mice.

METHODS

The pharmacokinetics of total alkaloids (TA) was investigated in SD rat plasma by a fully-validated LC-MS/MS method. Then, an ovalbumin (OVA)-sensitized airways allergic inflammatory model was established, in which mice were intra-gastrically administrated by 3 times a day (8.3 and 16.7mg/kg) based on the pharmacokinetic behavior of TA) and single (25, 50mg/kg) treatment regimen. Dexamethasone was used as a positive control for corticosteroid drugs. Cellular infiltration was assessed in the broncho-alveolar lavage fluid (BALF). Expressions of interleukin-4 (IL-4) and interleukin-10 (IL-10) in the BALF were determined, levels of immunoglobulin E (IgE) and eotaxin in serum were measured, and superoxide dismutase (SOD) activities as well as malondialdehyde (MDA) content in the serum and BALF were examined. Finally, histopathological examination in the lung was assessed by H. E. staining.

RESULTS

The time course of plasma concentration of 4 bioactive indole alkaloids fitted an open two-compartment model after oral administration of total alkaloids at doses of 10, 25, and 50mg/kg. The area under the curve and the maximum concentration values of four major alkaloids increased dose-dependently, and half-life suggested a short-lasting pharmacological effect. Then, an ovalbumin-provoked airways allergic inflammatory model indicated that the pharmacological effect of administration of total alkaloids 3 times a day was a little better than that of single dose daily. The percentage of eosinophils in BALF was reduced obviously and the pathological damage of lung was also attenuated. There was also a significant reduction in IL-4 and promotion in IL-10 in the BALF. Serum IgE and eotaxin expression also significantly decreased in treated animals. Furthermore, the activity of SOD elevated remarkably and lipid peroxidation product (MDA) decreased in the administrated mice.

CONCLUSION

The pharmacological effects administrated for 3 times a day had precedence over single dose daily, which was related to the prolonged retention time and the maintained plasma concentration. Moreover, scholaricine and vallesamine might be responsible for the treatment of allergic asthma, mainly in total alkaloids.

Astragalus membranaceus modulates Th1/2 immune balance and activates PPARγ in a murine asthma model

Astragalus membranaceus, a traditional Chinese herb, has been used to improve airway inflammation and asthma. The present study investigated whether A. membranaceus has immunotherapeutic effects on asthma, a chronic inflammatory mucosal disease that is associated with excess production of IgE, eosinophilia, T helper 2 (Th2) cytokines, and bronchial hyperresponsiveness. An ovalbumin (OVA)-induced, chronic inflammatory airway murine asthma model was used to examine the status of pulmonary inflammation after the administration of A. membranaceus. The IgE levels in serum and bronchoalveolar lavage fluid showed a tendency to decrease after the administration of A. membranaceus. The number of eosinophils decreased and infiltration of inflammatory cells and collagen deposition declined in lung sections after A. membranaceus administration. The RNA and protein levels of Th2 cytokines and the ratio of the GATA3/T-bet mRNA levels decreased after A. membranaceus treatment. Furthermore, the mRNA level of peroxisome proliferator-activated receptor γ (PPARγ), a nuclear hormone receptor, increased in the lung tissues of A. membranaceus-treated mice. Finally, an A. membranaceus water extract activated PPARγ activity in either human embryonic kidney 293 (HEK293) or A549 cells in a PPARγ-responsive element-containing luciferase reporter assay. These results indicate that A. membranaceus has an inhibitory effect on airway inflammation in a murine model of asthma through modulating the imbalanced relationship between Th1 and Th2 cytokines.

The effect of atorvastatin on lung histopathology in a murine model of chronic asthma

INTRODUCTION

Atorvastatin is a statin group medicine that reduces the level of serum cholesterol; thus it is used to treat hypercholesterolaemia. Independent of the cholesterol-lowering property of statins they also have anti-inflammatory and immunomodulating effects. This study aimed to investigate the effect of atorvastatin on histological changes in the lungs in a murine model of chronic asthma.

MATERIALS AND METHODS

Twenty-eight BALB/c mice in Group I, II, III and IV were divided into four groups. All the mice except the control group (Group I) were sensitised with ovalbumin. Intraperitoneal injection with saline, atorvastatin (10mg/kg), dexametazon (1mg/kg) was administered to Group II, Group III, and Group IV respectively for five consecutive days. Mice were sacrificed 24h after the last drug administration. All the histological properties of lung tissue samples from all groups were evaluated with light and electron microscopy. In addition, IL-4 and IL-5 levels of the lung tissue were measured.

RESULTS

When Group II and Group III (atorvastatin) were compared, thicknesses of basement membrane and subepithelial smooth muscle layer, height of epithelium, number of mast and goblet cells were significantly lower in Group III. In comparing Group III (atorvastatin) and Group IV (dexamethasone), all the improvements in histological parameters were similar. In addition, the IL-4 and IL-5 levels of the lung tissue were significantly lower in atorvastatin group (Group III) compared to placebo-treated group.

CONCLUSION

Atorvastatin had a beneficial effect on histological changes in a chronic murine model of asthma.

Beneficial effects of erythropoietin on airway histology in a murine model of chronic asthma

BACKGROUND

Erythropoietin (EPO) is originally defined as a haematopoietic growth factor, but also has anti-inflammatory effects through cytokine modulation. This anti-inflammatory and cytokine modulating effect has not been investigated for the treatment of asthma. We aimed to determine the beneficial effects of erythropoietin on lung histology of murine model of chronic asthma.

METHODS

Thirty-five BALB/c mice were divided into five groups: I; II; III; IV; and control group. All groups except control group were sensitised and challenged with ovalbumin. Mice with experimentally induced asthma in Group I received saline; Group II EPO 500IU/kg; Group III EPO 1000IU/kg; and Group IV dexamethasone 1mg/kg intraperitoneally once a day in the last five days of the challenge period. Animals were sacrificed 24h after the last administration of study drugs. Histological findings of airways were evaluated by light and electron microscopic examination.

RESULTS

All histological parameters of asthma in the group treated with a high dose of EPO (Group III) were significantly ameliorated when compared with the group treated with saline (Group I). In comparison to the group treated with low dose of EPO (Group II) and the group treated with saline (Group I), basement membrane thicknesses and number of mast cells were significantly lower in the group treated with low dose of EPO (Group II). All histological parameters were similar between the group treated with high dose of EPO (Group III) and the group treated with dexamethasone (Group IV) except higher number of mast cells in the group treated with high dose of EPO (Group III). Additionally, the results of all histological parameters in the group treated with high dose of EPO (Group III) were significantly better when compared with the group treated with low dose of EPO (Group II).

CONCLUSIONS

We found that EPO ameliorated histological changes of chronic murine model of asthma. Further studies are needed to evaluate the efficacy of EPO in the treatment of asthma.

Mesenchymal stem cells ameliorate the histopathological changes in a murine model of chronic asthma

Asthma therapies are effective in reducing inflammation but airway remodeling is poorly responsive to these agents. New therapeutic options that have fewer side effects and reverse chronic changes in the lungs are essential. Mesenchymal stem cells (MSCs) are promising for the development of novel therapies in regenerative medicine. This study aimed to examine the efficacy of MSCs on lung histopathology in a murine model of chronic asthma. BALB/c mice were divided into four groups: Group 1 (control group, n=6), Group 2 (ovalbumin induced asthma only, n=10), Group 3 (ovalbumin induced asthma + MSCs, n=10), and Group 4 (MSCs only, n=10). Histological findings (basement membrane, epithelium, subepithelial smooth muscle thickness, numbers of goblet and mast cells) of the airways and MSC migration were evaluated by light, electron, and confocal microscopes. In Group 3, all early histopathological changes except epithelial thickness and all of the chronic changes were significantly ameliorated when compared with Group 2. Evaluation with confocal microscopy showed that no noteworthy amount of MSCs were present in the lung tissues of Group 4 while significant amount of MSCs was detected in Group 3. Serum NO levels in Group 3, were significantly lower than Group 2. The results of this study revealed that MSCs migrated to lung tissue and ameliorated bronchial asthma in murine model. Further studies are needed to evaluate the efficacy of MSCs for the treatment of asthma.

Forskolin compared with beclomethasone for prevention of asthma attacks: a single-blind clinical trial

This single-blind study compared the efficacy of oral forskolin versus inhaled beclomethasone for mild or moderately persistent adult asthma. Patients were randomly assigned to receive forskolin (one 10-mg capsule orally per day; n = 30) or beclomethasone (two 50 microg inhalations every 12 h; n = 30) for 2 months. No statistically significant improvement occurred in any lung function parameter in the forskolin-treated patients. Subjects in the beclomethasone-treated group presented a slight but statistically significant improvement in percentage forced expiratory volume in 1 s (FEV(1)), percentage forced expiratory flow in the middle (25 - 75%) expiratory phase (FEF(25 - 75%)) and percentage forced vital capacity (FVC) after 2 months of treatment, though the improvement in absolute values for FEV(1), FEF(25 - 75%), FVC and FEV(1):FVC did not reach statistical significance. There was no statistically significant difference between the forskolin and beclomethasone treatment groups for any lung function parameter at baseline or after treatment. None of the beclomethasone-treated patients had an asthma attack and one forskolin-treated patient had a mild asthma attack during the 2-month study period. More studies are needed in adult asthma patients to confirm whether forskolin may be a useful preventive treatment for mild or moderately persistent adult asthma.

Bambusae Caulis in Taeniam extract reduces ovalbumin-induced airway inflammation and T helper 2 responses in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Bambusae Caulis in Taeniam (BC) was known as traditional herbal medicine with anti-inflammatory property in the Orient.

AIM OF THE STUDY

Allergic asthma is inflammatory disease of airways associated with enhanced T helper (Th) 2 lymphocytes responses to allergens, leading to eosinophilic infiltration and elevated serum IgE levels. Although there were some studies that BC extract had an anti-inflammatory property, there was no study on asthma. In present study, we investigated the suitability of BC extract as a therapeutic candidate in the treatment of allergic airway disease in ovalbumin-induced asthma model.

MATERIALS AND METHODS

Balb/C mice (female, 6 weeks old) were treated by ovalbumin sensitization and nebulization, and used as asthma model. The number of eosinophil in bronchoalveolar lavage (BAL) fluid and the degree of eosinophila were investigated by hematoxylin and eosin stain and the infiltration of inflammatory cells into lung tissues was examined by staining by hematoxylin and eosin solution. The levels of interleukin (IL)-4 in BAL fluid, immunoglobulin E (IgE) in serum, interferon (IFN)-gamma and IL-4 production in splenocyte culture from Balb/C mice (not treated, 6 weeks old) that incubated with or without BC extract for 48 h were determined by enzyme-linked immunosorbent assay.

RESULTS

The level of eosinophils was decreased by treatment of the animals with BC extract (40 mg/kg) and correspondingly, a significantly lowered degree of eosinophila was also reported (p<0.01). In lung tissue, BC extract reduced the increased immune cell infiltration induced by OVA (p<0.05). Furthermore, the levels of IL-4 and IgE in BAL fluid or serum up-regulated by OVA was decreased by BC extract. Finally, IFN-gamma production was significantly increased (p<0.01), while IL-4 production significantly decreased (p<0.01), after treatment of the culture supernatants of splenocytes with BC extract.

CONCLUSIONS

These results indicated that BC extract reduces OVA-induced airway inflammation and Th 2 response in mice, suggesting that BC extract can be a therapeutic candidate for allergic airway disease, including asthma.

Similar efficacy of ciclesonide once daily versus fluticasone propionate twice daily in patients with persistent asthma

This 12-week, double-blind, parallel-group study compared the efficacy and safety of once daily ciclesonide and twice daily fluticasone propionate in patients aged 12-75 years with persistent asthma. Patients were randomized to once-daily ciclesonide 80 micro g (n = 278) or 160 micro g (n = 271), or twice daily fluticasone propionate 88 micro g (n = 259) (all ex-actuator). Significant improvements from baseline were seen in all three treatment groups for forced expiratory volume in 1 second, asthma symptom scores and rescue medication use (all p < 0.0001). Asthma exacerbation rates were low (each ciclesonide group, n = 2; fluticasone group, n = 1). Adverse event reporting indicated good tolerability. Once daily ciclesonide 80 micro g or 160 micro g showed comparable efficacy and tolerability to twice daily fluticasone propionate 88 micro g in persistent asthma.

A randomized study comparing ciclesonide and fluticasone propionate in patients with moderate persistent asthma

OBJECTIVE

To compare the effects of once-daily ciclesonide and twice-daily fluticasone propionate in patients with moderate persistent asthma.

METHODS

Patients aged 12-75 years with moderate bronchial asthma entered a 1-4 week run-in period. For inclusion into the 12-week, randomized, open-label treatment period, patients had to have a forced expiratory volume in 1s (FEV1) of either 60-80% of predicted or 80% of predicted and a defined use of rescue medication and asthma symptoms, depending on previous treatment. Patients received ciclesonide 320 microg once daily (ex-actuator) or fluticasone propionate 200 microg twice daily. Primary efficacy endpoint was change from baseline in FEV1.

RESULTS

In total, 474 patients were randomized. FEV1 increased significantly from baseline with ciclesonide and fluticasone propionate in the intention-to-treat (ITT) and per-protocol (PP) analyses (all p < 0.0001). Treatment difference was -31 mL (95% confidence interval [CI]: -121, 59) in the PP analysis, demonstrating non-inferiority of ciclesonide. Similar findings were seen for other measures of lung function. In the ITT population, asthma symptom scores and rescue medication use decreased with both treatments (all p < 0.0001). Improvement in health-related quality of life (HRQoL) from baseline was significantly greater with ciclesonide than fluticasone (p = 0.005; one-sided). There were no cases of oral candidiasis in patients receiving ciclesonide and nine cases (3.8%) in those receiving fluticasone propionate (p = 0.002; one-sided).

CONCLUSIONS

Treatment with once-daily ciclesonide and twice-daily fluticasone propionate resulted in similar improvements in lung function in patients with moderate persistent asthma. Ciclesonide showed significant improvements in oral candidiasis and HRQoL over fluticasone.

Bronchial mucosal inflammation and upregulation of CXC chemoattractants and receptors in severe exacerbations of asthma

BACKGROUND

A study was undertaken to test the hypothesis that severe exacerbations of asthma are characterised by increased bronchial mucosal neutrophilia associated with upregulation of neutrophil chemoattractant ligands and their specific cell surface receptors.

METHODS

Immunohistology and in situ hybridisation were applied to endobronchial biopsy specimens from three groups: (1) 15 patients admitted to hospital with a severe exacerbation of asthma (E-asthma), (2) 15 with stable asthma (S-asthma) and (3) 15 non-atopic and non-smoker surgical controls (NSC).

RESULTS

There were significantly more neutrophils and eosinophils in the epithelium and subepithelium of patients in the E-asthma group (median (range) neutrophils 7 (0-380) and 78 (10-898)/mm2, eosinophils 31 (0-167) and 60 (6-351)/mm2, p<or=0.01 compared with NSC: 0 (0-10, 0-7, 0-18 and 0-3)/mm2, respectively), resulting in similar final densities of eosinophils and neutrophils. With respect to neutrophil chemoattractants and receptors, counts of CXCL5, CXCL8, CXCR1 and CXCR2 mRNA-positive cells in the subepithelium of the E-asthma group were, respectively, 5, 4, 4 and 18 times greater (p<or=0.01) than those of the NSC group. In the E-asthma group, cells expressing CXCL5 or CXCR2 were eightfold and threefold more frequent than those expressing CXCL8 or CXCR1 mRNA, respectively (p<0.01). CXCL5 and CXCR2 in E-asthma were associated with the number of eosinophils (r=0.59 and 0.66, p<0.02 for both) rather than the number of neutrophils.

CONCLUSION

In severe exacerbations of asthma there is a bronchial mucosal neutrophilia, eosinophilia and upregulation of CXC chemoattractants and their receptors. CXCL5 and CXCR2 have an association with eosinophila only, and these represent potentially new targets for treatment in exacerbations of asthma.

New anti-inflammatory therapies and targets for asthma and chronic obstructive pulmonary disease

Asthma and chronic obstructive pulmonary disease (COPD) are diseases of the airways with an underlying inflammatory component. The prevalence and healthcare burden of asthma and COPD is still rising and is predicted to continue to rise in the foreseeable future. Beta-agonists and corticosteroids form the basis of the therapies available to treat asthma. However, the treatments available for COPD, corticosteroids and anticholinergics, reduce the number and severity of exacerbations, but have a limited effect on slowing the progression of the disease. The inflammatory processes underlying the pathology of asthma have received a great deal of attention and more recently, those underlying COPD have begun to be elucidated. This has resulted in the identification of new targets that will allow the development of novel approaches by the pharmaceutical industry, which will be able to focus its efforts in an attempt to provide new and improved therapies to treat these debilitating diseases. The resultant therapies should impinge on the underlying development of these diseases rather than providing symptomatic relief or palliative treatment alone. This review will outline new targets and novel approaches currently under investigation, which may provide opportunities for novel anti-inflammatory therapeutic interventions that slow or halt disease progression in asthma and COPD.

Comparable efficacy of ciclesonide once daily versus fluticasone propionate twice daily in asthma

BACKGROUND

Inhaled corticosteroids are the mainstay of therapy in asthma, but local and systemic side effects and adherence remain a concern. Ciclesonide is an inhaled corticosteroid with on-site lung activation that provides potent anti-inflammatory activity and has been shown to have a good safety profile, even at high doses.

OBJECTIVE

The aim of this study was to compare the efficacy and safety of once-daily ciclesonide versus twice-daily fluticasone propionate at comparable daily doses in patients with asthma.

METHODS

In this multicenter, randomized, double-blind, double-dummy, parallel group study, 529 patients were randomized to ciclesonide 160 microg once daily or fluticasone propionate 88 microg twice daily for 12 weeks. The primary endpoint was change in lung function.

RESULTS

Both ciclesonide and fluticasone propionate significantly improved forced expiratory volume in 1s, forced vital capacity, and morning peak expiratory flow compared with baseline (p<0.0001 for all variables). Both medications reduced asthma symptoms and rescue medication use within the first 24 h. At the tested dose, both medications were equally safe and well tolerated.

CONCLUSION

Ciclesonide 160 microg once daily was as effective as fluticasone propionate 88 microg twice daily in improving lung function and asthma symptoms, and in reducing rescue medication use in patients with asthma.

Anti-IL-13 monoclonal antibody inhibits airway hyperresponsiveness, inflammation and airway remodeling

Asthma is a chronic inflammatory disease characterized by reversible bronchial constriction, pulmonary inflammation and airway remodeling. Current standard therapies for asthma provide symptomatic control but fail to target the underlying disease pathology. Furthermore, no therapeutic agent is effective in preventing airway remodeling. Interleukin 13 (IL-13) is a pleiotropic cytokine produced mainly by T cells. A substantial amount of evidence suggests that IL-13 plays a critical role in the pathogenesis of asthma. Therefore, a neutralizing anti-IL-13 monoclonal antibody could provide therapeutic benefits to asthmatic patients. To test the concept we have generated a neutralizing rat anti-mouse IL-13 monoclonal antibody, and evaluated its effects in a chronic mouse model of asthma. Chronic asthma-like response was induced in ovalbumin (OVA) sensitized mice by repeated intranasal OVA challenges. After weeks of challenge, mice developed airway hyperresponsiveness (AHR) to methacholine stimulation, severe airway inflammation, hyper mucus production, and subepithelial fibrosis. When given at the time of each intranasal OVA challenge, anti-IL-13 antibody significantly suppressed AHR, eosinophil infiltration, proinflammatory cytokine/chemokine production, serum IgE, and most interestingly, airway remodeling. Taken together, these results strongly suggest that a neutralizing anti-human IL-13 monoclonal antibody could be an effective therapeutic agent for asthma.

Increased relaxation of immature airways to β2-adrenoceptor agonists is related to attenuated expression of postjunctional smooth muscle muscarinic M2 receptors

Spontaneous or agonist-induced contraction of airway smooth muscle can be observed very early in fetal life, thus explaining the possible occurrence of bronchospasm in very low birth weight infants within the first days of life. In an attempt to better manage such bronchospasms, the aim of the present study was to investigate the age-specific modifications in airway smooth muscle relaxation to β2-agonists and muscarinic antagonists using a combination of functional and molecular techniques. In the rat, isometric relaxation to the β2-agonist salbutamol was examined in tracheae; we also examined muscarinic receptor expression (M2R and M3R mRNA levels) in airway smooth muscle by immunochemistry, Western blotting, and real-time PCR. Compared with adults, salbutamol-induced relaxation was twofold greater in immature rat isolated tracheae preconstricted by carbachol. This effect was associated with a lower expression of M2R in the smooth muscle of immature animals (sixfold and almost twofold as assessed by immunochemistry and Western blotting, respectively). Real-time PCR data indicate that changes in M2R expression according to age occurred at a posttranscriptional level. In adult airways, there was a significantly greater functional efficacy of M2R blockade by methoctramine compared with that shown in immature rats. Because of the limited availability of human neonate lung tissue, only the molecular part of the study was performed, and we observed a qualitatively similar effect, i.e., a lower M2R expression in the neonatal airway smooth muscle, although this was quantitatively smaller. We conclude that β2-agonist-induced relaxation is enhanced in immature compared with adult airways as a result of greater postjunctional M2R expression in adult airway smooth muscle. This finding may be of importance in the clinical management of bronchoconstriction in neonates.

New advances and potential therapies for the treatment of asthma

Asthma is a disease of the airways with an underlying inflammatory component. The prevalence and healthcare burden of asthma is still rising and is predicted to continue to rise in the current century. Inhaled beta(2)-adrenoceptor agonists and corticosteroids form the basis of the treatments available to alleviate the symptoms of asthma. There is a need for novel, safe treatments to tackle the underlying inflammation that characterizes asthma pathology. Furthermore, there is a requirement for new treatments to be developed as oral therapy in order to alleviate patient compliance issues, especially in children. A multitude of new approaches and new targets are being investigated, which may provide opportunities for novel therapeutic interventions in this debilitating disease. For simplicity, these approaches can be divided into two categories. The first comprises therapies directed against specific components or steps seen in allergic asthma. By 'components' we mean the key inflammatory cells (T cells [in particular T(h)2], B cells, eosinophils, mast cells, basophils and antigen presenting cells [APC]) and mediators (immunoglobulin E [IgE], cytokines, histamines, leukotrienes and prostanoids) believed to be involved in the chronic inflammation seen in asthma. By 'steps' we mean the allergic response, such as antigen processing and presentation, T(h)2-cell activation, B-cell isotype switching, mast cell involvement and airway remodeling. The other category of novel approaches to disease modification in asthma encompasses general anti-inflammatory therapies including phosphodiesterase 4 (PDE4) inhibitors, p38 mitogen-activated protein kinase (MAPK) inhibitors, peroxisome proliferator-activated receptor-gamma (PPARgamma) agonists, and lipoxins.

Novel therapies for the treatment of inflammatory airway disease

Asthma and chronic obstructive pulmonary disease (COPD) are diseases of the airways with an underlying inflammatory component. The prevalence and healthcare burden of asthma and COPD is still rising and is predicted to continue to rise in the current century. The beta-agonists and corticosteroids form the basis of the treatments available to alleviate the symptoms of asthma, whereas the treatments available for COPD have been shown to have a limited effect on slowing the progression of the disease. Asthma and COPD are both in need of novel, safe treatments to tackle the underlying inflammation that characterises their pathology. The inflammatory processes inherent in asthma and COPD provide the opportunity for innovative drug research. This review will outline the new approaches and targets being investigated, which may provide opportunities for novel therapeutic interventions in these debilitating diseases.