Inhaled corticosteroids for asthma: on-demand or continuous use

Role of Sulfur Compounds in Garlic as Potential Therapeutic Option for Inflammation and Oxidative Stress in Asthma

Asthma is a chronic inflammatory disease in the airways with a multifactorial origin but with inflammation and oxidative stress as related pathogenic mechanisms. Garlic (Allium sativum) is a nutraceutical with different biological properties due to sulfur-containing natural compounds. Studies have shown that several compounds in garlic may have beneficial effects on cardiovascular diseases, including those related to the lungs. Therefore, it is possible to take advantage of the compounds from garlic as nutraceuticals for treating lung diseases. The objective of this article is to review the biological properties of the sulfur compounds present in garlic for the treatment of asthma, as well as the cellular mechanisms involved. Here, we discuss the potential therapeutic effects of garlic compounds in the modulation of inflammation and oxidative stress, as well as its antibiotic and antiviral activities for identifying and testing potential treatment options for asthma management.

Inhaled corticosteroids and risk of influenza in patients with asthma: a meta-analysis of randomized controlled trials

BACKGROUND

It was reported that inhaled corticosteroids (ICS) treatment may affect local immunity and microbial community of the airway. However, whether ICS treatment increases the risk of influenza in patients with asthma remains unclear. This meta-analysis aimed to compare the risk of influenza between ICS and non-ICS treatment in patients with asthma.

METHODS

PubMed, Embase, Cochrane Library and Clinical Trials.gov were searched from inception until November 2019. Randomized controlled trials (RCTs) were included that compared ICS treatment with non-ICS treatment on the risk of influenza in patients with asthma. Meta-analyses were conducted by the Peto approach and Mantel-Haenszel approach with corresponding 95% CIs.

RESULTS

Nine trials involving 6486 patients were included in this meta-analysis. The risk of influenza was not different between ICS treatment and the control groups (Peto OR: 1.01, 95% CI 0.74-1.37, P = 0.95). The results of subgroup analyses based on durations (long-term and short-term treatment), doses (high-, medium- and low-dose treatment) and types (fluticasone and budesonide treatment) of ICS were consistent with the above pooled results. Moreover, subgroup analysis based on patients' age also revealed that use of ICS did not increase the risk of influenza. Results of the two meta-analysis approaches were similar.

CONCLUSIONS

Use of ICS does not increase the risk of influenza in patients with asthma. This study adds to safety evidence of ICS as a regular controller treatment for patients with asthma.

Discontinuation of inhaled corticosteroids in patients with controlled asthma: The DISCO (Discontinuation of Inhaled Steroid in Controlled asthmatics Over 6 months) study

BACKGROUND

Although inhaled corticosteroids (ICSs) are the recommended first-line therapy for asthma, determining whether to continue or discontinue ICS treatment in patients with mild asthma remains challenging for clinicians. Several studies have revealed that patients with mild-persistent asthma maintained a well-controlled state after ICS withdrawal. However, the long-term outcomes of ICS withdrawal have not yet been determined.

OBJECTIVE

To determine the possible clinical outcomes of the discontinuation of ICS in patients with well-controlled mild asthma.

METHODS

We investigated the clinical outcomes of discontinuing ICSs in patients with well-controlled mild asthma and compared the time to loss of control (LOC) between patients who stopped ICS treatment (ICS withdrawal group, IWG) and those who continued treatment for 3 years (continuous ICS group, CIG).

RESULTS

A significant difference in the time to LOC was observed between the IWG and CIG (hazard ratio, 2.56; 95% confidence interval, 1.52-4.33; P < .001). Increasing fractional exhaled nitric oxide levels (P = 0.008) and sputum eosinophil counts (%) (P = 0.015) revealed a weak but significant association with LOC risk in the CIG. The sputum eosinophil counts (P = 0.039) and serum total immunoglobulin E levels (P = 0.014) were significantly higher in the LOC group than in the non-LOC group of the CIG.

CONCLUSION

Our results suggest that the maintenance of ICS treatment may help keep patients' asthma under control. Furthermore, patients with LOC had significantly higher sputum eosinophil counts in the CIG than those in the non-LOC group. Therefore, continuous ICS use by patients with mild, well-controlled asthma could be associated with good clinical outcomes.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: KCT0002234.

Comparing the Protection Imparted by Different Fraction Extracts of Garlic (Allium sativum L.) against Der p-Induced Allergic Airway Inflammation in Mice

Garlic (Allium sativum L.) has been used extensively as a food ingredient and medicinally, but the effect on asthmatic airway inflammation has not been studied in detail. We accordingly explored the protective effects exerted by various garlic fraction extracts against airway inflammation with Dermatophagoides pteronyssinus (Der p)-induced allergic asthma in vivo and in vitro. Garlic extraction was realized using n-hexane, dichloromethane, ethylacetate, n-butanol, and water in sequence to obtain different fraction extracts. Mice were orally administered different fractions (80 mg/kg) daily for four weeks. The histological results showed that the water fraction could ameliorate lung-based goblet cell hyperplasia, inflammatory cell infiltration, and mucus hypersecretion. The water fraction extracts decreased IgE and IgG1, and they decreased inflammatory cells as quantified in bronchoalveolar lavage fluid (BALF); however, they increased IgG2a in serum. Moreover, the water fraction extracts increased IFN-γ and IL-12 (both constituting Th1 cytokines) in BALF, but they reduced IL-13, -4, and -5 (all constituting Th2 cytokines), and also inhibited the expression of IL-1β, IL-6, and TNF-α. The water fraction also inhibited the PI3K/Akt/NF-κB signal pathways in A549 cells. These findings suggest that water fraction extracts of garlic have a clear anti-inflammatory effect on Der p-induced allergic asthma.

Inhaled corticosteroids and risk of upper respiratory tract infection in patients with asthma: a meta-analysis

BACKGROUND

Recent studies have suggested a possible association between respiratory infection and the use of inhaled corticosteroids (ICS). We aimed to ascertain the risk of upper respiratory tract infection (URTI) with long-term inhaled corticosteroid use among patients with asthma.

METHODS

Through a comprehensive literature search of PubMed, Cochrane Library, EMBASE, and Google Scholar from inception to May 2018, we included randomized controlled trials of any ICS vs. a control treatment for asthma, with reporting of URTI as an adverse event. We conducted meta-analyses by the Peto approaches to generate summary estimates comparing ICS with non-ICS treatment on the risk of URTI.

RESULTS

Seventeen trials (15,336 subjects) were included. Compared with non-ICS treatment, ICSs were associated with a significantly increased risk of URTI (Peto OR, 1.24; 95% CI 1.08-1.42; I² = 5%, p = 0.002). Subgroup analyses were performed for different dose, both high- and low-dose ICSs were associated with a significantly increased risk of URTI (high dose: Peto OR, 1.46; 95% CI 1.05-2.03; I² = 0%; p = 0.03) (low dose: Peto OR, 1.20; 95% CI 1.04-1.39; I² = 25%; p = 0.01). Moreover, fluticasone was observed with an increased risk of URTI (Peto OR, 1.18; 95% CI 1.02-1.38; p = 0.03; heterogeneity: I² = 21%) but not budesonide, low-dose fluticasone treatment was associated with a significantly higher risk of URTI but not high dose.

CONCLUSIONS

This study raises safety concerns about the risk of URTI associated with ICS use in patients with asthma, but it should be further investigated.

Establishment of different experimental asthma models in mice

Asthma is a complex disease. The heterogeneity of airway inflammation during asthma indicates there are different mechanisms involved. In order to further study the mechanisms of asthma, different mouse models were established to mimic corresponding subtypes of asthma in clinic. Eosinophilic asthma was established by intraperitoneal injections of ovalbumin (OVA) on day 0 and day 7, followed by inhalation of aerosolized OVA on days 14–17. Neutrophilic asthma was established by transtracheal administration of a high dose of lipopolysaccharide (LPS; 10 µg) on days 15 and 17 in combination with OVA sensitization and challenge as described previously. Mix-granulocytic asthma was established by transtracheal administration of a low dose of LPS (1 µg) on day 15, in combination with OVA sensitization and challenge as described previously. Compared with healthy controls, increased numbers of eosinophils, elevated levels of T helper (Th)2 cytokines in bronchoalveolar lavage fluid (BALF), and moderated inflammation of lung tissues was observed in eosinophilic asthma. Increased numbers of neutrophils, elevated levels of Th1 and Th17 cytokines in BALF and severe inflammation of lung tissues was observed in neutrophilic asthma. Increased numbers of both eosinophils and neutrophils, elevated levels of Th1, Th2 and Th17 cytokines in BALF and severe inflammation of lung tissues was observed in mix-granulocytic asthma. Airway hyperresponsiveness, increased bronchial mucus secretion, and elevated serum levels of immunoglobin (Ig)E and OVA-IgE were detected in all three asthma models. Dexamethasone reduced the pathogenic symptoms of the mice in eosinophilic asthma, however had no effect on neutrophilic asthma or mix-granulocytic asthma. Each model of asthma established in the present study represents corresponding subtypes of asthma in clinic.

Inhaled Corticosteroids and Respiratory Infections in Children With Asthma: A Meta-analysis

CONTEXT

Inhaled corticosteroids (ICS) are associated with an increased risk of pneumonia in adult patients with chronic obstructive pulmonary disease.

OBJECTIVE

To assess the association between ICS use and risk of pneumonia and other respiratory infections in children with asthma.

DATA SOURCES

We searched PubMed from inception until May 2015. We also searched clinicaltrials.gov and databases of pharmaceutical manufacturers.

STUDY SELECTION

We selected randomized trials that compared ICS with placebo for at least 4 weeks in children with asthma.

DATA EXTRACTION

We included 39 trials, of which 31 trials with 11 615 patients contributed data to meta-analyses.

RESULTS

The incidence of pneumonia was 0.58% (44/7465) in the ICS group and 1.51% (63/4150) in the placebo group. The meta-analysis of 9 trials that revealed at least 1 event of pneumonia revealed a reduced risk of pneumonia in patients taking ICS (risk ratio [RR]: 0.65; 95% confidence interval [CI]: 0.44 to 0.94). Using risk difference as effect measure, the meta-analysis including all 31 trials revealed no significant difference in the risk of pneumonia between the ICS and placebo groups (risk difference: -0.1%; 95% CI: -0.3% to 0.2%). No significant association was found between ICS and risk of pharyngitis (RR: 1.01; 95% CI: 0.87 to 1.18), otitis media (RR: 1.07; 95% CI: 0.83 to 1.37), and sinusitis (RR: 0.89; 95% CI: 0.76 to 1.05).

LIMITATIONS

Lack of clearly defined criteria for respiratory infections and possible publication bias.

CONCLUSIONS

Regular use of ICS may not increase the risk of pneumonia or other respiratory infections in children with asthma.