Mechanisms of asthma exacerbation

Self-administration of omalizumab: why not? A literature review and expert opinion

Introduction: Omalizumab is used to treat severe uncontrolled allergic asthma and chronic spontaneous urticaria (CSU), and is approved for self-administration in prefilled syringes. It is thus important to understand the advantages, critical issues, and indications for home administration.Areas covered: The present review summarizes the available evidence on home administration of omalizumab in asthma and CSU to illustrate the advantages derived from self-administration of patients in this setting.Expert opinion: The available data suggest that patients can safely administer biologics at home with suitable training, and that home administration is time saving and cost-effective. The majority of patients with severe asthma or CSU treated with omalizumab are likely to be suitable candidates for self-administration, which can be proposed to anyone that the clinician deems suitable. In addition to clinicians, pharmacists can also play a key role in managing patients who are prescribed home administration. A practical flow chart is proposed on selection of patients and their management during home administration. Self-administration of biologics can be considered as a valid alternative to traditional injections in a clinical setting, and the evidence has shown that no major issues need to be overcome in terms of safety or efficacy.

Synthesis, transport and mechanism of a type I prodrug: L-carnitine ester of prednisolone

Aerosol glucocorticoid medications have become more and more important in treating BA (bronchial asthma). Although these agents are dosed to directly target airway inflammation, adrenocortical suppression and other systematic effects are still seen. To tackle this problem in a novel way, two L-carnitine ester derivatives of prednisolone (as the model drug), namely, PDC and PDSC, were synthesized to increase the absorption of prednisolone across the human bronchial epithelial BEAS-2B cells by the organic cation/carnitine transporter OCTN2 (SLC22A5) and then to slowly and intracellularly release prednisolone. The transport of prednisolone, PDC and PDSC into the human bronchial epithelial BEAS-2B cells was in the order PDSC > prednisolone > PDC at 37 °C. It was found that PDSC displayed 1.79-fold increase of uptake compared to prednisolone. Transport of PDSC by BEAS-2B was temperature-, time-, and Na(+)-dependent and saturable, with an apparent K(m) value of 329.74 μM, suggesting the involvement of carrier-mediated uptake. An RT-PCR study showed that organic cation/carnitine transporters OCTN1 and OCTN2 are expressed in BEAS-2B cells, but little in HEK293T cells. The order of uptake by HEK293T was prednisolone > PDC > PDSC. In addition, the inhibitory effects of organic cations such as L-carnitine, ergothioneine, TEA(+) and ipratropium on PDSC uptake in BEAS-2B cells were in the order L-carnitine > ipratropium > TEA(+) > ergothioneine, whereas their inhibitory effects on PDSC uptake in HEK293T cells were negligible. Finally, in vitro LPS-induced IL-6 production from BEAS-2B was more and longer suppressed by PDSC than prednisolone and PDC. All of these results suggested PDSC may be an attractive candidate for asthma treatment.

Similar efficacy of ciclesonide versus prednisolone to treat asthma worsening after steroid tapering

RATIONALE

Oral corticosteroids effectively treat asthma exacerbations but are associated with well-described side effects.

OBJECTIVE

This study compared the efficacy and safety of a high dose of an inhaled corticosteroid with oral prednisolone in patients with worsening of their asthma after medication withdrawal.

METHODS

Patients tapered off their inhaled corticosteroids until they reached predefined criteria of "worsening asthma". Randomized patients (n=130) were treated double blind with either ciclesonide 800mug twice daily (starting with 800mug hourly for 3h after randomization) or prednisolone 40mg once daily for 2 weeks. Spirometry, daily asthma symptoms, morning and evening peak expiratory flow and blood parameters were assessed in all, methacholine challenge and inflammatory measures were determined in induced sputum in a subset of patients.

RESULTS

Ciclesonide was as effective as prednisolone in improving forced expiratory flow in 1s, morning peak expiratory flow and symptoms, the latter improving more rapidly with ciclesonide. No differences were found in methacholine responsiveness or inflammatory measures in sputum or blood. Ciclesonide caused significantly less reduction in morning plasma cortisol levels (p<0.0001).

CONCLUSION

This study shows that inhaled ciclesonide (800mug twice daily) has comparable efficacy to oral prednisolone (40mg once daily) to regain asthma control in patients with asthma worsening. The more rapid onset and smaller effect on cortisol suppression suggest a better safety profile of ciclesonide.

Dipeptidyl peptidase I-dependent neutrophil recruitment modulates the inflammatory response to Sendai virus infection

The role of innate immunity in the pathogenesis of asthma is unclear. Although increased presence of neutrophils is associated with persistent asthma and asthma exacerbations, how neutrophils participate in the pathogenesis of asthma remains controversial. In this study, we show that the absence of dipeptidyl peptidase I (DPPI), a lysosomal cysteine protease found in neutrophils, dampens the acute inflammatory response and the subsequent mucous cell metaplasia that accompanies the asthma phenotype induced by Sendai virus infection. This attenuated phenotype is accompanied by a significant decrease in the accumulation of neutrophils and the local production of CXCL2, TNF, IL-1beta, and IL-6 in the lung of infected DPPI-/- mice. Adoptive transfer of DPPI-sufficient neutrophils into DPPI-/- mice restored the levels of CXCL2 and enhanced cytokine production on day 4 postinfection and subsequent mucous cell metaplasia on day 21 postinfection. These results indicate that DPPI and neutrophils play a critical role in Sendai virus-induced asthma phenotype as a result of a DPPI-dependent neutrophil recruitment and cytokine response.

Comparison of asthma-related functional consequences and health care utilization among children with and without upper respiratory infection-triggered wheezing

OBJECTIVE

We compared differences in functional consequences and health care utilization in middle school-age children, based on whether they reported wheezing triggered by upper respiratory infections (URI-TW).

METHODS

Information on asthma symptoms, URI-TW, and functional consequence and health care use outcomes was collected from approximately 128,000 children; symptomatic participants were included in the analysis. Adjusted prevalence odds ratios were used to make comparisons.

RESULTS

URI-TW was significantly associated with most outcomes examined, with stronger associations at increasing levels of outcomes for sleep disturbances, school absences, activity limitations, physician visits, emergency room visits, hospitalizations, inhaler use, and tablets/pills to help breathing.

CONCLUSION

Children who report URI-TW during their middle school years experience substantial morbidity and high health care utilization compared with symptomatic children without URI-TW.

Aggregates of ultrafine particles impair phagocytosis of microorganisms by human alveolar macrophages

We investigated whether exposure of alveolar macrophages to aggregates of ultrafine carbon particles affected subsequent phagocytosis of microorganisms. Human alveolar macrophages were obtained by bronchoalveolar lavage and exposed to aggregates of ultrafine carbon particles or diesel exhaust particles (DEP) for 20 h before measurements of phagocytosis. The particle loads were estimated to be comparable to those of air pollution exposure with established health effects in humans. Phagocytotic activity was measured as attachment and ingestion of four different test particles (amorphous silica particles, yeast cells from Candida albicans, and Cryptococcus neoformans opsonized with specific IgG or fresh serum) that bind to scavenger, mannose, Fc, and complement receptors, respectively. Carbon preloading significantly impaired the attachment and ingestion process (P<0.01) for all particles, except for yeast cells from C. neoformans opsonized with specific IgG. On the average, the accumulated attachment decreased by 30% and the ingested fraction decreased by 10%. Loading of alveolar macrophages with either aggregates of ultrafine DEP or carbon particles impaired the phagocytosis of silica test particles in a similar way. Exposure of human alveolar macrophages to aggregates of carbon or DEP, in concentrations relevant to human environmental exposures, caused significant impairment of phagocytosis of silica particles and microorganisms. The inhibitory effect on particle phagocytosis mediated by four different receptors suggests that air pollution particles cause a general inhibition of macrophage phagocytosis. Such an effect may contribute to increased susceptibility to infections and, for example, result in more exacerbations of asthma and chronic obstructive pulmonary disease.

Presence of asthma risk factors and environmental exposures related to upper respiratory infection-triggered wheezing in middle school-age children

Viral respiratory infections and exposure to environmental constituents such as tobacco smoke are known or suspected to trigger wheezing/asthma exacerbations in children. However, few population-based data exist that examine the relationship between wheezing triggered by viral respiratory infections and environmental exposures. In this investigation we used population-based data to evaluate differences in exposures between symptomatic middle school-age children who did and did not report wheezing triggered by viral respiratory infections. As part of the North Carolina School Asthma Survey (NCSAS), a 66-question data instrument was used to collect information from children enrolled in North Carolina public middle schools during the 1999-2000 school year. Associations between exposures and upper respiratory infection-triggered wheezing (URI-TW) among symptomatic children were examined using adjusted prevalence odds ratios (PORs). Video methods developed for the International Study of Asthma and Allergies in Childhood were used to assess wheezing. Among the 33,534 NCSAS symptomatic participants, positive associations were observed between most exposures and URI-TW. Reported presence of all allergy variables (PORs ranging from 2.11 to 2.45) was more strongly associated with URI-TW than either smoking or other exposures. Presence of URI-TW was higher at increasing levels of tobacco smoke exposure, but no apparent dose-response effect was observed for other indoor air pollutants. URI-TW in middle school children is most associated with reported allergen sensitivity, relative to other asthma risk factors and environmental exposures. Data from this investigation may be useful in developing assessment, screening, and targeting strategies to improve asthma and wheezing management in children.

Hygienic hand antiseptics: should they not have activity and label claims against viruses?

Enteric and respiratory viruses are among the most frequent causes of human infections, and hands play an important role in the spread of these and many other viral diseases. Regular and proper hand hygiene by caregivers and food handlers in particular is essential to decontaminate hands and potentially interrupt such spread. What would be considered a proper decontamination of hands? Handwashing with regular soap and water is often considered sufficient, but what of hygienic handwash and handrub antiseptic products? Are they more effective? The evidence suggests that some clearly are. Activity against bacteria may not reflect the ability of hygienic hand antiseptics to deal with viruses, especially those that are nonenveloped. In spite of the acknowledged importance of hands as vehicles for viruses, there is a lack of suitable regulatory mechanism for handwash or handrub products to make claims of efficacy against viruses. This is in contrast with the ability of general-purpose disinfectants to make antiviral claims, although transmission of viruses from surfaces other than those of reusable medical devices may play only a minor role in virus transmission. This review discusses the (1). recent information on the relative importance of viruses as human pathogens, particularly those causing enteric and respiratory infections; (2). the survival of relevant viruses on human hands in comparison with common gram-negative and gram-positive bacteria; (3). the potential of hands to transfer or receive such contamination on casual contact; (4). role of hands in the spread of viruses; (5). the potential of hygienic measures to eliminate viruses from contaminated hands; (6). relative merits of available protocols to assess the activity of hygienic hand antiseptics against viruses; and (7). factors considered crucial in any tests to assess the activity of hygienic hand antiseptics against viruses. In addition, this review proposes surrogate viruses in such testing and discusses issues for additional consideration by researchers, manufacturers, end-users, and regulators.

Toll-like receptors as potential therapeutic targets for multiple diseases

The family of Toll-like receptors (TLRs) is receiving considerable attention as potential regulators and controllers of the immune response through their ability to recognize pathogen-associated molecular patterns. The discovery that endogenous ligands, as well as microbial components, are recognized by TLRs, and that small-molecular-mass synthetic compounds activate TLRs, raised interest in these receptors as potential targets for the development of new therapies for multiple diseases. In this review, we discuss the current and future use of TLR agonists or antagonists in chronic inflammatory diseases and highlight potential problems that are associated with such approaches.

Development of an asthma vaccine: research into BCG

Asthma is an atopic disorder characterised by the activation and recruitment of eosinophils to the lung resulting in chronic swelling and inflammation of the airways. Allergic disorders such as atopic asthma and dermatitis have been increasingly prevalent in developed countries, and the inverse correlation between exposure to major diseases such as tuberculosis and atopy prevalence has been reported. Intranasal administration of Mycobacterium bovis-Bacillus Calmette-Guerin (BCG) has been demonstrated to suppress airway eosinophilia in a model of atopic asthma. This immunomodulation is attributed to the ability of interferon (IFN)-gamma produced by BCG-specific T(H)1 lymphocytes to inhibit the development of lung T(H)2 responses such as airway eosinophilia. The mechanism of IFNgamma-induced inhibition is yet to be defined, but could involve activation of macrophages, direct suppression of developing T(H)2 lymphocytes, or altered dendritic cell activation and antigen presentation. Mycobacteria such as BCG and certain mycobacterial fractions are strong inducers of a T(H)1 immune response. The effectiveness of BCG in inhibiting atopic airway eosinophilia suggests its potential as a useful therapeutic agent in the treatment of atopic asthma.