Effect of a 4-week treatment with theophylline on sputum eosinophilia and sputum eosinophil chemotactic activity in steroid-naive asthmatics

Theophylline for the management of respiratory disorders in adults in the 21st century: A scoping review from the American College of Clinical Pharmacy Pulmonary Practice and Research Network

Theophylline is an oral methylxanthine bronchodilator recommended as alternate therapy for the treatment of asthma and chronic obstructive pulmonary disease (COPD). However, it is not generally recommended for the treatment of other respiratory disorders such as obstructive sleep apnea (OSA) or hypoxia. Most clinical practice guidelines rely on evidence published prior to the year 2000 to make these recommendations. This scoping review aimed to gather and characterize evidence describing theophylline for the management of respiratory disorders in adults between January 1, 2000 and December 31, 2020. Databases searched included Ovid MEDLINE, Embase, CINAHL Complete, Scopus, and International Pharmaceutical Abstracts. This review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) extension for scoping reviews. Studies were included if they were published in English, theophylline was used for any respiratory disorder, and the study outcomes were disease- or patient-oriented. After removal of duplicates, 841 studies were screened and 55 studies were included. Results aligned with current clinical guideline recommendations relegating theophylline as an alternative therapy for the treatment of respiratory disorders, in favor of inhaled corticosteroids and inhaled bronchodilators. This scoping review identified the need for future research including: theophylline versus other medications deemed alternative therapies for asthma and COPD, meta-analyses of low-dose theophylline, and studies evaluating evidence-based patient-oriented outcomes for OSA, hypoxia, ventilator-induced diaphragmatic dysfunction, and spinal cord injury-related pulmonary function.

A review on airway biomarkers: exposure, effect and susceptibility

Current research in pulmonology requires the use of biomarkers to investigate airway exposure and diseases, for both diagnostic and prognostic purposes. The traditional approach based on invasive approaches (lung lavages and biopsies) can now be replaced, at least in part, through the use of non invasively collected specimens (sputum and breath), in which biomarkers of exposure, effect and susceptibility can be searched. The discovery of specific lung-related proteins, which can spill over in blood or excreted in urine, further enhanced the spectrum of airway specific biomarkers to be studied. The recent introduction of high-performance 'omic' technologies - genomics, proteomics and metabolomics, and the rate at which biomarker candidates are being discovered, will permit the use of a combination of biomarkers for a more precise selection of patient with different outcomes and responses to therapies. The aim of this review is to critically evaluate the use of airway biomarkers in the context of research and clinical practice.

Theophylline inhibits the differentiation of human monocyte into dendritic cell potentially via adenosine receptor antagonism

BACKGROUND

Theophylline has an anti-inflammatory action that may account for its clinical effectiveness in the reduction of inflammatory cells in the airways. Dendritic cells (DCs) are professional antigen-presenting cells, capable of priming naïve T cells, and play key roles in the activation of immune responses in asthma.

OBJECTIVE

The purpose of this study was to investigate the effects of theophylline on human monocyte differentiation into DCs and whether this involved antagonism of adenosine receptors.

METHODS

Peripheral human blood monocytes were cultured in the presence of granulocyte/macrophage-colony stimulating factor and IL-4 to induce DC differentiation. The cells were incubated with theophylline, KF17837 (a selective A2a receptor antagonist) and enprofylline (A2b receptor antagonist) and co-incubated with selective adenosine A1 and A2a receptor agonists, a phosphodiesterase inhibitor (rolipram) and adenosine deaminase (ADA) to determine their effects on DC differentiation. In addition, depletion of adenosine receptors by small interfering RNA (siRNA) was also examined.

RESULTS

Monocytes differentiated into myeloid DCs in the culture system. The number of DCs was remarkably reduced by 60-70% when theophylline was administered at a therapeutic concentration. This effect was concentration-dependently exacerbated, was partly mediated by cellular apoptosis and was effectively reversed by the addition of the A1 agonists [2-chloro-N(6)-cyclopentyladenosin, N(6)-cyclohexyladenosine, and N-ethylcarboxamidoadenosine (NECA)] or the A2a agonist (CGS-21680, NECA). The depletion of the adenosine A1 receptor by siRNA and addition of ADA remarkably reduced DC differentiation. Meanwhile, both enprofylline and rolipram had little effect.

CONCLUSION

Our findings suggest that the adenosine A1 (and possibly coordinated with A2a) receptors contribute to DC differentiation and survival. These findings provide further evidence that theophylline has an anti-inflammatory action in bronchial asthma.

Benefits of low-dose inhaled fluticasone on airway response and inflammation in mild asthma

RATIONALE

Current guidelines suggest that asthma should be controlled with the lowest dose of maintenance medication required.

OBJECTIVES

To evaluate the effects of a low dose of inhaled corticosteroid compared to a placebo, on airway inflammation and responsiveness in patients with mild symptomatic asthma.

METHODS

In this randomized double-blind, placebo-controlled, parallel group study, we looked at the influence of inhaled fluticasone propionate 250 microg/day for 3 months followed by 100 microg/day for 9 months on airway inflammation and methacholine responsiveness in non-smoking subjects with mild allergic asthma. Subjects were evaluated at baseline and 3, 6, 9 and 12 months after treatments; a 2-week evaluation of respiratory symptoms and peak expiratory flow measurements was done before each visit.

RESULTS

Fifty-seven subjects completed the 3-month study period. Airway responsiveness, expressed as the PC20 methacholine, increased by 0.27 and 1.14 doubling concentrations, respectively, in placebo-treated (n=33) and in fluticasone-treated (n=24) asthmatic subjects (p=0.03). An additional improvement in PC20 up to 2.16 doubling concentrations was observed in the fluticasone-treated group during the 9-month lower-dose treatment (p=0.0004, end of low-dose period compared with placebo). Sputum eosinophil counts decreased after 3 months of fluticasone 250 microg/day compared with placebo (p<0.0001) and remained in the normal range during the 9-month lower-dose treatment. Respiratory symptoms and peak expiratory flows did not change significantly throughout the study in both groups.

CONCLUSION

In mild asthma, keeping a regular minimal dose of ICS after asthma control has been achieved, may lead to a further reduction in airway responsiveness and keep sputum eosinophil count within the normal range.

Serum and bronchial lavage fluid concentrations of IL-8, SLPI, sCD14 and sICAM-1 in patients with COPD and asthma

BACKGROUND

Airway inflammation is associated with an increased expression and release of inflammatory reactants that regulate processes of cell migration, activation and degranulation. The purpose of this study was to quantify bronchial lavage (BAL) fluid and serum levels of chemokine (IL-8), secretory leukocyte protease inhibitor (SLPI), soluble intracellular adhesion molecules-1 (sICAM-1) and sCD14, as surrogate markers of inflammatory and immune response in asthma and chronic obstructive pulmonary disease (COPD) patients with similar disease duration time.

METHODS

Biomarkers in serum and BAL fluid from asthma (n=13) and COPD (n=25) patients were measured using commercially available ELISA kits.

RESULTS

We found that in asthma and COPD groups the concentrations of IL-8 and SLPI are significantly higher in BAL fluid than in serum, while levels of sICAM-1 and sCD14 in BAL fluid are significantly lower than in serum. Of these 4 measured biomarkers, only the BAL IL-8 was higher in COPD patients when compared to asthma (P<0.05). In both groups, BAL IL-8 correlated with SLPI (r=0.577, P<0.01 and r=0.589, P<0.05, respectively). In patients with COPD the BAL sICAM-1 correlated with sCD14 (r=0.576, P<0.01), while in asthma patients BAL sICAM-1 correlated with FEV(1)/FVC (r=0.418, P<0.01). Moreover, in asthma patients the serum SLPI correlated with sCD14 (r=0.688, P<0.01) and serum sICAM-1 negatively correlated with FEV(1)/FVC (r=-0.582, P<0.05).

CONCLUSION

Our findings point to the importance of selecting a correct biological fluid when analyzing specific biomarkers, and also show that of 4 measured biomarkers, only the BAL IL-8 was higher in COPD patients when compared to asthma.

Effect of low-dose theophylline on airway inflammation in COPD

OBJECTIVE

Recent studies have shown that theophylline may exert anti-inflammatory effects on neutrophils. We undertook to assess the effect of theophylline on airway inflammation in COPD.

METHODOLOGY

We performed a 4-week randomized double-blind, placebo-controlled study in 11 theophylline-naive patients with mild to moderate COPD. After a 1-week run-in period, six subjects were administered 400 mg/day theophylline (Theodur; Nikken Chemicals Co. Ltd, Tokyo, Japan) for 4 weeks, while five subjects were administered a placebo. Induced sputum was obtained before and after the run-in period and then after 2 and 4 weeks of treatment. Cell differential count and levels of interleukin-8, matrix metalloproteinase-9, neutrophil elastase (NE), myeloperoxidase (MPO), alpha1-antitrypsin (alpha1-AT), leukotriene B4 and tissue inhibitor of metalloproteinases-1 (TIMP-1) were assessed.

RESULTS

No variable was significantly different during the run-in period or with placebo treatment. In contrast, theophylline treatment significantly decreased NE and MPO levels at 4 weeks, although the cell differential count did not change appreciably as a result of treatment.

CONCLUSION

These results suggest that 4 weeks of theophylline treatment attenuates neutrophil-associated inflammation in the airways of mild to moderate COPD patients. However, the clinical benefits remain to be determined.

Differential pharmacokinetics of theophylline in elderly patients

The clinical use of theophylline as a first-line bronchodilator has declined during the last two decades. However, in many clinical settings, such as an emergency bronchial asthma attack, theophylline may have a first-line role, in combination with beta(2)-adrenoreceptor agonists and corticosteroids, for improving the asthmatic status. Furthermore, many therapeutic mechanisms of theophylline for bronchial asthma have been reported, and recent studies have suggested that theophylline therapy may have a beneficial role in the management of chronic stable asthma as well as exacerbated disease. However, theophylline has a low therapeutic index because the bronchodilation it produces has a linear relationship with logarithmic increases in serum concentration for the therapeutic range of 5-20 mg/L. Thus, the knowledge of its basic pharmacokinetics and the factors that can alter its clearance is clinically relevant for physicians. Especially when used in elderly asthmatic patients, dosage adjustment of theophylline is a requisite since the elderly have several risk factors that may increase the plasma theophylline level, such as reduced clearance, various underlying diseases and multiple coadministered drugs. After theophylline treatment has been initiated, therapeutic drug monitoring is required.

Asthma exacerbations and sputum eosinophil counts: a randomised controlled trial

BACKGROUND

Treatment decisions in asthma are based on assessments of symptoms and simple measures of lung function, which do not relate closely to underlying eosinophilic airway inflammation. We aimed to assess whether a management strategy that minimises eosinophilic inflammation reduces asthma exacerbations compared with a standard management strategy.

METHODS

We recruited 74 patients with moderate to severe asthma from hospital clinics and randomly allocated them to management either by standard British Thoracic Society asthma guidelines (BTS management group) or by normalisation of the induced sputum eosinophil count and reduction of symptoms (sputum management group). We assessed patients nine times over 12 months. The results were used to manage those in the sputum management group, but were not disclosed in the BTS group. The primary outcomes were the number of severe exacerbations and control of eosinophilic inflammation, measured by induced sputum eosinophil count. Analyses were by intention to treat.

FINDINGS

The sputum eosinophil count was 63% (95% CI 24-100) lower over 12 months in the sputum management group than in the BTS management group (p=0.002). Patients in the sputum management group had significantly fewer severe asthma exacerbations than did patients in the BTS management group (35 vs 109; p=0.01) and significantly fewer patients were admitted to hospital with asthma (one vs six, p=0.047). The average daily dose of inhaled or oral corticosteroids did not differ between the two groups.

INTERPRETATION

A treatment strategy directed at normalisation of the induced sputum eosinophil count reduces asthma exacerbations and admissions without the need for additional anti-inflammatory treatment.

Sputum eosinophil count in a large population of patients with mild to moderate steroid-naive asthma: distribution and relationship with methacholine bronchial hyperresponsiveness

BACKGROUND

Although airway eosinophilia is seen as a cardinal feature of asthma, data eosinophilia are still lacking on the proportion of the asthma group exhibiting raised airway eosinophilia. This study aimed to assess the distribution of sputum eosinophil count and its relationship with methacholine bronchial hyperresponsiveness in mild to moderate steroid-naive asthmatic people.

METHODS

Sputum was induced by inhalation of hypertonic saline (NaCl 4.5%) in 118 mild to moderate steroid-naive asthmatic people consecutively recruited from our outpatient clinic, and in 44 healthy people. The asthma group was selected on the basis of an forced expiratory volume in 1 s (FEV(1)) of > or = 70% predicted, and a provocative methacholine concentration causing a fall of 20% in FEV(1) (PC20 methacholine; PC(20)M) < or = 16 mg/ml.

RESULTS

In the asthma group, the median (range) of the percentage and the absolute values of sputum eosinophils were 4.8% (0-75) and 38 10(3)/g (0-14,191), respectively, vs 0% (0-2.3) (P < 0.001) and 0 10(3)/g (0-53) (P < 0.001) in healthy participants. Based on the 95% percentile for normal values calculated from our healthy group, 69% of the asthma group had significantly raised sputum eosinophil count (that is > 2%). In the asthma group, multiple regression analysis followed by a stepwise procedure revealed that sputum eosinophil count was significantly and inversely associated with PC(20)M accounting for 16% of its total variance (P < 0.001) while neutrophil counts positively related to PC(20)M accounting for 4% of total variance (P < 0.05). By contrast, no significant relationship was found between either eosinophil or neutrophil counts and the slope of forced vital capacity (FVC) vs FEV(1) from the methacholine challenge.

CONCLUSIONS

We conclude that two-thirds of people in the mild to moderate asthma group had increased sputum eosinophilia, which plays a limited role in determining the degree of methacholine airway hyperresponsiveness.

Eosinophils, eosinophilic cytokines (interleukin-5), and antieosinophilic therapy in asthma

Eosinophils are believed to be key effector cells in producing the bronchial mucosal inflammation characteristic of allergic asthma. Given the perceived importance of eosinophils in allergic inflammation, they have been logical therapeutic targets. As knowledge of eosinophil biology increases, eosinophils are targeted with specific therapies blocking their maturation, activation, and chemotaxis. Therapeutic targets include eosinophil-specific cytokines, primarily interleukin-5, and chemokines, eg, eotaxin. Several studies over the last year have reported on therapies effective at reducing eosinophil numbers in asthmatics, including two humanized monoclonal antibodies against interleukin-5 and recombinant human interleukin-12. Surprisingly, despite their effectiveness at depleting eosinophils, there was no evidence of clinical improvement in any of the parameters studied. These and all other relevant studies published within the last year are reviewed by this article. After publication of these studies, some commentators questioned the role of eosinophils in allergic inflammation. Current evidence for and against eosinophils as effector cells in asthma is reviewed.

Low-dose theophylline does not exert its anti-inflammatory effects in mild asthma through upregulation of interleukin-10 in alveolar macrophages

BACKGROUND

There is accumulating evidence that theophylline has anti-inflammatory or immunomodulatory effects. This may be, in part, mediated via an upregulation in the production of the anti-inflammatory cytokine interleukin (IL)-10. We determined whether low-dose theophylline (LDT) would increase the production of IL-10, and attenuate the production of proinflammatory cytokines by alveolar macrophages.

METHODS

In a double-blind, placebo-controlled, crossover study involving 15 steroid-free patients with mild asthma, fiberoptic bronchoscopy and bronchoalveolar lavage (BAL) were performed at the end of the treatment and placebo periods. Alveolar macrophages were cultured in vitro, and we measured their release of IL-10, GM-CSF, and TNF-alpha. We also measured IL-10 production in whole blood together with the number of monocytes and T cells expressing intracellular IL-10 by flow cytometry.

RESULTS

LDT did not increase the production of IL-10, or attenuate the production of GM-CSF or TNF-alpha by alveolar macrophages. However, after theophylline treatment, there was a significant reduction in mean (SD) (95% CI) BAL eosinophil number from 3.4 (1.7)% (95% CI 2.4-4.4) to 1.7 (1.0)% (95% CI 1.1-2.3) compared with placebo (P<0.05). Similarly, there was no increase in whole-blood IL-10 release or in the number of monocytes and T cells expressing intracellular IL-10 after treatment.

CONCLUSIONS

LDT has an anti-inflammatory effect in asthma; however, this effect is not mediated via the production of IL-10 or the attenuation of GM-CSF or TNF-alpha. The mechanisms of theophylline activity remain to be determined.

The use of sputum cell counts to evaluate asthma medications

Total and differential cell counts from hypertonic-induced, dithiothreitol-dispersed sputum provide reproducible measurements of airway inflammatory cell counts, which are responsive to treatment with anti-inflammatory drugs. They have helped to understand the kinetics of inflammatory cell changes in asthma after the reduction of corticosteroids and the subsequent re-introduction of treatment. They have identified that the presence of sputum eosinophilia in asthma, chronic cough and chronic airflow limitation is a predictor of steroid-responsiveness and of lack of 'asthma control'. They can be used to study the dose-response effect of inhaled corticosteroids and may be useful to establish the relative potency of different corticosteroid formulations and delivery devices. Sputum cell counts are also useful to study the potential anti-inflammatory effects of drugs like theophylline, long-acting beta-adrenoceptor agonists, leukotriene antagonists and newer drugs in development. They may be helpful to select add-on therapy to corticosteroids in 'difficult-to-control' asthma.