Inhaled therapy for acute adult asthma

Effect of Bavachinin and its derivatives on T cell differentiation

Bavachinin, which can be isolated from the Chinese herb Fructus Psoraleae, has the potential as a potent anti-asthma drug. However, the extremely low water solubility of Bavachinin limits its application. In this study, two new derivatives of Bavachinin, i.e., compounds A and B, whose water solubility is better than that of Bavachinin, were synthesized via biotransformation. A comparative investigation was then performed on the effects of these two new derivatives, along with Bavachinin, on T cell differentiation. The results showed that they have different effects. Bavachinin and compound B inhibited green fluorescent protein (GFP) production from the T cells of IL-4-GFP-enhanced transcript (4GET) mice, whereas compound A did not. The effect was mainly attributed to the inhibition of GATA-3 protein production. Bavachinin and compound B can inhibit the production of GATA-3 mRNA, but they showed different effects on the production of T-bet mRNA. Compound B increased the production of T-bet mRNA, whereas Bavachinin did not. The results will be very useful for optimizing Bavachinin so that potent anti-allergic drugs can be developed. The structure-activity relationship of Th2 was revealed based on the difference between Bavachinin and compound B. This finding can enrich the database of preliminary drug screening from their chemical structures.

Treatment of allergic inflammation and hyperresponsiveness by a simple compound, Bavachinin, isolated from Chinese herbs

Asthmatic inflammation is mediated by a type 2 helper T cell (Th2) cytokine response, and blocking Th2 cytokine production is proven to have a potent therapeutic effect against asthmatic inflammation. Using IL-4-green fluorescent protein (GFP) reporter mice, we demonstrated that Bavachinin, a single compound isolated from a Chinese herb, significantly inhibited Th2 cytokine production, including IL-4, IL-5 and IL-13. Notably, this compound almost completely blocked inflammation in the ovalbumin (OVA)-sensitized animal asthma model. Furthermore, we demonstrated that this chemical selectively affects the level of GATA-3, most likely by affecting the stability of GATA-3 mRNA. Our results demonstrate, for the first time, the potential therapeutic value of this single compound derived from Chinese herbs.

Ameliorative potential of alpha-ketoglutaric acid (AKG) on acute lung injuries induced by ammonia inhalation in rats

INTRODUCTION

Toxicants such as ammonia, if inhaled, can damage respiratory tract leading to acute lung injury and pulmonary edema. Besides being a possible threat for the workers in chemical industry, easy availability and the toxic nature of ammonia may be used by terror groups for inflicting mass casualty among vulnerable population. In the present study, we have evaluated the therapeutic efficacy of alpha-ketoglutarate (AKG) to mitigate acute effects of ammonia on lung structure and antioxidant status in experimental animals.

METHODS

Acute lung injury (ALI) models were developed by inhalation of aerosols of liquid ammonia in male Sprague Dawley rats. AKG (5%) respiratory fluid was inhaled by nebulization once daily for 5 days. Animals were euthanized and their blood samples were collected for hematology and serum biochemistry analysis. Total cell count, total protein (TP), lactate dehydrogenase (LDH), antioxidant enzyme activity (CAT, SOD, GSH), and malonaldialdehyde (MDA) formation were measured in bronchoalveolar lavage (BAL) fluid.

RESULTS

Treatment with AKG showed significant lung protection by lowering the levels of total cell count, TP, LDH, superoxide dismutase (SOD), and MDA in BAL fluid. There was a marked increase in catalase (CAT) and glutathione (GSH) content of BAL fluid post-AKG inhalation. Histopathology of lung tissue correlated with cellular and biochemical findings indicate therapeutic efficacy of AKG against ammonia-induced lung injuries.

CONCLUSIONS

The data suggest a possible therapeutic role of AKG inhalation against ammonia-induced structural and inflammatory changes in the lung.

Review article: management of acute severe and near-fatal asthma

Despite a decline in the Australian overall asthma mortality, near-fatal/critical asthma continues to be a significant management issue for emergency physicians and intensivists. Near-fatal asthma is a unique subtype of asthma, with a variety of clinical presentations, requiring rapid and aggressive intervention. The pharmacological and non-pharmacological management of near-fatal asthma remains very complex. The present review discusses recent advances and evidence for current available strategies targeting this time critical emergency.

Interleukin-4 upregulates RhoA protein via an activation of STAT6 in cultured human bronchial smooth muscle cells

Interleukin-4 (IL-4) is believed to play a role in allergic bronchial asthma, and has been suggested to cause hyperresponsiveness of airway smooth muscle. In the present study, the effects of IL-4 on the expression of RhoA protein, a monomeric GTP-binding protein that contributes to the contraction of smooth muscle, were determined in cultured human bronchial smooth muscle cells (hBSMCs). Incubation of hBSMCs with IL-4 (100ng/mL) caused a distinct phosphorylation of signal transducer and activator of transcription 6 (STAT6), a major signal transducer activated by IL-4, indicating that IL-4 is capable of activating signal transduction in the hBSMCs directly. IL-4 also caused a significant increase in the expression level of RhoA protein: the peak of the upregulation of RhoA protein was observed at 12-24h after the IL-4 treatment. Both the phosphorylation of STAT6 and the upregulation of RhoA protein induced by IL-4 were inhibited by the co-incubation with AS1517499, a selective inhibitor of STAT6, in a concentration-dependent fashion. These findings suggest that IL-4 is capable of inducing an upregulation of RhoA via an activation of STAT6 in cultured hBSMCs. The RhoA upregulation induced by IL-4, one of the Th2 cytokines upregulated in the airways of allergic bronchial asthmatics, might result in an augmentation of bronchial smooth muscle contractility, that is one of the causes of airway hyperresponsiveness.

Differentiating chronic obstructive pulmonary disease from asthma

PURPOSE

Chronic obstructive pulmonary disease (COPD) and asthma are chronic diseases that are increasing worldwide in incidence, prevalence, and burden. The purpose of this article is to provide nurse practitioners (NPs) with the information necessary to make a differential diagnosis and to understand the different treatment approaches to these two diseases.

DATA SOURCES

Peer-reviewed journal articles, book chapters, and evidence-based Internet sources.

CONCLUSIONS

NPs who are familiar with the pathophysiology that differentiates COPD from asthma can make an appropriate diagnosis and initiate effective pharmacologic and nonpharmacologic interventions, which may lead to a reduced incidence of exacerbations.

IMPLICATIONS FOR PRACTICE

A misdiagnosis of COPD or asthma leads to inadequate management of patients and to escalating healthcare costs. An early and accurate diagnosis can help to ensure optimal and cost-effective management of patient care.

Effects of nebulized ketamine on allergen-induced airway hyperresponsiveness and inflammation in actively sensitized Brown-Norway rats

Since airway hyperresponsiveness (AHR) and allergic inflammatory changes are regarded as the primary manifestations of asthma, the main goals of asthma treatment are to decrease inflammation and maximize bronchodilation. These goals can be achieved with aerosol therapy. Intravenous administration of the anesthetic, ketamine, has been shown to trigger bronchial smooth muscle relaxation. Furthermore, increasing evidence suggests that the anti-inflammatory properties of ketamine may protect against lung injury. However, ketamine inhalation might yield the same or better results at higher airway and lower ketamine plasma concentrations for the treatment of asthma. Here, we studied the effect of ketamine inhalation on bronchial hyperresponsiveness and airway inflammation in a Brown-Norway rat model of ovalbumin(OVA)-induced allergic asthma. Animals were actively sensitized by subcutaneous injection of OVA and challenged by repeated intermittent (thrice weekly) exposure to aerosolized OVA for two weeks. Before challenge, the sensitizened rats received inhalation of aerosol of phosphate-buffered saline (PBS) or aerosol of ketamine or injection of ketamine respectivity. Airway reactivity to acetylcholine (Ach) was measured in vivo, and various inflammatory markers, including Th2 cytokines in bronchoalveolar lavage fluid (BALF), as well as induciable nitric oxide synthase (iNOS) and nitric oxide (NO) in lungs were examined. Our results revealed that delivery of aerosolized ketamine using an ultrasonic nebulizer markedly suppressed allergen-mediated airway hyperreactivity, airway inflammation and airway inflammatory cell infiltration into the BALF, and significantly decreased the levels of interleukin-4 (IL-4) in the BALF and expression of iNOS and the concentration of NO in the inflamed airways from OVA-treated rats. These findings collectively indicate that nebulized ketamine attenuated many of the central components of inflammatory changes and AHR in OVA-provoked experimental asthma, potentially providing a new therapeutic approach against asthma.

Ciclesonide: a novel inhaled corticosteroid

Inhaled corticosteroids (ICS) are a mainstay in the treatment of persistent asthma, a disease with increasing prevalence and cost implications worldwide. However, long-term use of currently available ICS is associated with local adverse effects that include hoarseness and oral candidiasis. In addition, systemic adverse effects including adrenal cortical suppression, osteoporosis, growth retardation, cataracts and glaucoma are also present. Ciclesonide is a novel ICS, which promises to provide airway anti-inflammatory efficacy that is comparable with that of the available ICS in addition to reducing the risk for local and systemic adverse events. Ciclesonide is an agent that is inactive until it reaches its target site, the lung, where it is converted to its active metabolite desisobutyryl-ciclesonide. In addition, other favourable pharmacokinetic and pharmacodynamic characteristics such as high protein binding, low oral bioavailability and rapid clearance contribute to the efficacy and improved systemic safety profile of ciclesonide.

2003 canadian asthma consensus guidelines executive summary

BACKGROUND

Guidelines for the diagnosis and management of asthma have been published over the last 15 years; however, there has been little focus on issues relating to asthma in childhood. Since the last revision of the 1999 Canadian Asthma Consensus Report, important new studies, particularly in children, have highlighted the need to incorporate new information into the asthma guidelines. The objectives of this article are to review the literature on asthma published between January 2000 and June 2003 and to evaluate the influence of new evidence on the recommendations made in the 1999 Canadian Asthma Consensus Report and its 2001 update, with a major focus on pediatric issues.

METHODS

The diagnosis of asthma in young children and prevention strategies, pharmacotherapy, inhalation devices, immunotherapy, and asthma education were selected for review by small expert resource groups. The reviews were discussed in June 2003 at a meeting under the auspices of the Canadian Network For Asthma Care and the Canadian Thoracic Society. Data published through December 2004 were subsequently reviewed by the individual expert resource groups.

RESULTS

This report evaluates early-life prevention strategies and focuses on treatment of asthma in children, emphasizing the importance of early diagnosis and preventive therapy, the benefits of additional therapy, and the essential role of asthma education.

CONCLUSION

We generally support previous recommendations and focus on new issues, particularly those relevant to children and their families. This document is a guide for asthma management based on the best available published data and the opinion of health care professionals, including asthma experts and educators.

Management of mechanical ventilation in acute severe asthma: practical aspects

BACKGROUND

Acute severe asthma induces marked alterations in respiratory mechanics, characterized by a critical limitation of expiratory flow and a heterogeneous and reversible increase in airway resistance, resulting in premature airway closure, lung, and chest wall dynamic hyperinflation and high intrinsic PEEP.

DISCUSSION

These abnormalities increase the work of breathing and can lead to respiratory muscle fatigue and life-threatening respiratory failure, in which case mechanical ventilation is life-saving. When instituting mechanical ventilation in this setting, a major concern is the risk of worsening lung hyperinflation (thereby provoking barotrauma) and inducing or aggravating hemodynamic instability. Guidelines for mechanical ventilation in acute severe asthma are not supported by strong clinical evidence. Controlled hypoventilation with permissive hypercapnia may reduce morbidity and mortality compared to conventional normocapnic ventilation. Profound pathological alterations in respiratory mechanics occur during acute severe asthma, which clinicians should keep in mind when caring for ventilated asthmatics.

CONCLUSION

We focus on the practical management of controlled hypoventilation. Particular attention must be paid to ventilator settings, monitoring of lung hyperinflation, the role of extrinsic PEEP, and administering inhaled bronchodilators. We also underline the importance of deep sedation with respiratory drive-suppressing opioids to maintain patient-ventilator synchrony while avoiding as much as can be muscle paralysis and the ensuing risk of myopathy. Finally, the role of noninvasive positive pressure ventilation for the treatment of respiratory failure during severe asthma is discussed.

Investigation of pulmonary deposition of a nebulized radiopharmaceutical agent in awake cats

OBJECTIVE

To determine whether conscious, unsedated cats will inhale a nebulized material administered via a facemask and whether this material will reach the lower airways.

ANIMALS

20 healthy adult cats.

PROCEDURE

Technetium Tc 99m-diaminetriaminopentaacetic acid (99mTc-DTPA) was nebulized into a spacer and administered to the cats via a closely fitting facemask. By use of a gamma camera, images were then immediately obtained to determine the distribution of 99mTc-DTPA within the lower airways.

RESULTS

Images obtained by use of the gamma camera revealed that all 20 cats had inhaled 99mTc-DTPA from the facemask. In each cat, deposition of the radiopharmaceutical agent was evident throughout the lung fields.

CONCLUSIONS AND CLINICAL RELEVANCE

Awake cats that were not used to the application of a facemask did inhale substances from such a device. Aerosolization of medications may be a feasible route of administration for cats with lower airway disease.

Acute asthma in adults: a review

All patients with asthma are at risk of having exacerbations. Hospitalizations and emergency department (ED) visits account for a large proportion of the health-care cost burden of asthma, and avoidance or proper management of acute asthma (AA) episodes represent an area with the potential for large reductions in health-care costs. The severity of exacerbations may range from mild to life threatening, and mortality is most often associated with failure to appreciate the severity of the exacerbation, resulting in inadequate emergency treatment and delay in referring to hospital. This review describes the epidemiology, costs, pathophysiology, mortality, and management of adult AA in the ED and in the ICU.