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

Therapeutic diminution of Interleukin-10 with intranasal theophylline administration in hyposmic patients

OBJECTIVE

To determine changes in nasal mucus Interleukin-10 (IL-10) before and after intranasal theophylline treatment in hyposmic patients, and the relationship of these changes to orally administered theophylline treatment.

DESIGN

IL-10 was measured in nasal mucus samples of 17 normal subjects and 39 patients with hyposmia of multiple etiologies by use of a sensitive spectrophotometric ELISA assay. Hyposmia is defined clinically by standardized evaluation of impaired olfactometry, as well as subjectively self reported by the patient.

RESULTS

Prior to treatment, IL-10 levels in nasal mucus were increased in hyposmic patients compared to controls. Following intranasal theophylline administration, over half of treated patients experienced a decrease of nasal mucus IL-10 toward control levels, correlated with a significant improvement in taste and smell function. Patients who increased with intranasal administration, similar to previously reported oral administration, showed no significant improvement in taste or smell function.

CONCLUSIONS

Nasal mucus IL-10 decreased in patients treated with intranasal theophylline. Mechanisms of action include phosphodiesterase and nuclear factor kappa-B inhibition, correlated with an improvement in both olfaction and gustation. IL-10 is induced by therapeutic and systemic administration of theophylline as with oral dosage, but reduced by lower and localized treatment.

Post-tuberculous lung disease: should we be using Theophylline?

Tuberculosis affects 10 million people and over 320,000 South Africans every year. A significant proportion of patients treated for tuberculosis develop post-tuberculous lung disease (PTBLD), a disease of chronic respiratory impairment for which there is a lack of affordable treatment options. PTBLD a heterogenous disorder that shares phenotypical features with chronic obstructive lung disease, bronchiectasis, lung fibrosis and destruction as well as pulmonary hypertension. There remains a paucity of proven pharmacotherapy for the management of PTBLD. Theophylline, a widely available and affordable medicine that has largely fell out of favour in high-income settings due to its toxicity and narrow therapeutic index, may be repositioned for the treatment of PTBLD. In this review, we unpack the potential role of theophylline in the management of PTBLD by reviewing the evidence for its bronchodilatory, anti-inflammatory and potential pleotrophic effects.

Comparison of anti-inflammatory mechanisms between doxofylline and theophylline in human monocytes

BACKGROUND

Methylxanthines are important pharmacological agents in the treatment of asthma and of chronic obstructive pulmonary diseases. The present study was designed to compare the ability of doxofylline and theophylline to modulate inflammatory pathways in human monocytes.

METHODS

Monocytes isolated from healthy anonymous human buffy coats were treated with doxofylline or theophylline in the presence of phorbol 12-myristate 13-acetate (PMA) or lipopolysaccharide (LPS), and their phenotype, the oxidative burst, cytokine expression and release, cAMP production, and protein kinase C (PKC) activity were evaluated.

RESULTS

Doxofylline and theophylline did not have overlapping effects on human monocytes. While sharing some common characteristics, they differed significantly in their selectivity. Theophylline affected LPS- above PMA-induced cellular responsivity, while doxofylline behaved in the opposite manner. Furthermore, when testing PKC activity, we found an inhibitory effect of doxofylline but not of theophylline, at equimolar doses.

CONCLUSIONS

In conclusion, our data support the growing hypothesis that doxofylline does not have a superimposable mechanism of action compared to theophylline, and this may both explain some differences in the risk/benefit ratio and may direct studies to tailor therapy for patients.

Theophylline

Theophylline (dimethylxanthine) has been used to treat airway diseases for more than 80 years. It was originally used as a bronchodilator, but the relatively high doses required are associated with frequent side effects, so its use declined as inhaled β2-agonists became more widely used. More recently it has been shown to have antiinflammatory effects in asthma and chronic obstructive pulmonary disease (COPD) at lower concentrations. The molecular mechanism of bronchodilatation is inhibition of phosphodiesterase (PDE)3, but the antiinflammatory effect may be due to inhibition of PDE4 and histone deacetylase-2 activation, resulting in switching off of activated inflammatory genes. Through this mechanism, theophylline also reverses corticosteroid resistance, and this may be of particular value in severe asthma and COPD, wherein histone deacetylase-2 activity is reduced. Theophylline is given systemically (orally as slow-release preparations for chronic treatment and intravenously for acute exacerbations of asthma). Efficacy is related to blood concentrations, which are determined mainly by hepatic metabolism, which may be increased or decreased in several diseases and by concomitant drug therapy. Theophylline is now usually used as an add-on therapy in patients with asthma not well controlled on inhaled corticosteroids with or without long-acting β2-agonists and in patients with COPD with severe disease not controlled by bronchodilator therapy. Side effects are related to plasma concentrations and include nausea, vomiting, and headaches due to PDE inhibition and at higher concentrations to cardiac arrhythmias and seizures due to adenosine A1-receptor antagonism. In the future, low-dose theophylline may be useful in reversing corticosteroid resistance in COPD and severe asthma.

Outpatient management of asthma in children

The principal aims of asthma management in childhood are to obtain symptom control that allows individuals to engage in unrestricted physical activities and to normalize lung function. These aims should be achieved using the fewest possible medications. Ensuring a correct diagnosis is the first priority. The mainstay of asthma management remains pharmacotherapy. Various treatment options are discussed. Asthma monitoring includes the regular assessment of asthma severity and asthma control, which then informs decisions regarding the stepping up or stepping down of therapy. Delivery systems and devices for inhaled therapy are discussed, as are the factors influencing adherence to prescribed treatment. The role of the pediatric health care provider is to establish a functional partnership with the child and their family in order to minimize the impact of asthma symptoms and exacerbations during childhood.

Low-dose theophylline restores corticosteroid responsiveness in rats with smoke-induced airway inflammation

Patients with chronic obstructive pulmonary disease (COPD) respond poorly to corticosteroids. Histone deacetylase-2 (HDAC-2) plays a pivotal role in many cases of steroid insensitivity. The main aim of this study was to restore the smoking-induced reduction in corticosteroid sensitivity by increasing HDAC-2 activity using low-dose theophylline. Rats were exposed to cigarette smoke (CS) and treated with budesonide and two doses of theophylline. Besides the pathologic examination and cell counting in the bronchoalveolar lavage fluid (BALF), the expression of HDAC-2 and CXC chemokine ligand-8 (CXCL-8) were measured. Airway inflammation induced by CS was demonstrated by pathologic changes of lung tissue and increased level of CXCL-8. CS exposure also markedly decreased HDAC-2 expression. Moreover, a negative correlation was found between HDAC-2 activity and a lung destruction index. The index was restored to control levels with inhaled corticosteroid treatment in combination with a low, not a high, dose of theophylline. These results indicate that low-dose theophylline might provide protection from smoke damage and improve the anti-inflammatory effects of steroids by increasing HDAC-2 activity.

Interactions between theophylline and salbutamol on cytokine release in human monocytes

The combination of beta(2)-adrenoceptor agonists (beta(2)-agonists) with inhaled steroids has become the standard treatment for mild to moderate asthma. Theophylline has also been combined successfully with inhaled steroids. However, the possible interaction between theophylline and beta(2)-agonists, with regard to their anti-inflammatory effects, has not been clarified. The aim of this study was to investigate the in vitro interaction between theophylline and salbutamol on cytokine generation from human monocytes and compare it with a similar interaction between dexamethasone and salbutamol. Purified monocytes from normal donors were pretreated with the drugs (alone or in combination) and stimulated with lipopolysaccharide for 24 h. Released tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6), and their corresponding mRNA expressions, were determined and analyzed. Salbutamol (>or= 0.1 microM) significantly inhibited the release of TNF-alpha, but also significantly enhanced that of IL-6. In contrast, theophylline (50 microM) and dexamethasone (0.1 microM) strongly inhibited the generation of both cytokines. It is noteworthy that when the drugs were used in combination the effects of theophylline and salbutamol were additive in inhibiting TNF-alpha release, but theophylline blocked the IL-6-enhancing effect of salbutamol. A similar effect was seen when dexamethasone was combined with salbutamol. These results show that beta(2)-agonists have opposing effects on the generation of TNF-alpha and IL-6, but that when they were combined with clinically relevant concentrations of theophylline, theophylline, like dexamethasone, was capable of augmenting the anti-inflammatory effects of the beta(2)-agonists while at the same time preventing their proinflammatory effect. Thus, theophylline may have a potentially useful steroid-sparing effect.

Theophylline

Theophylline (3-methyxanthine) has been used to treat airway diseases for over 70 years. It was originally used as a bronchodilator but the relatively high doses required are associated with frequent side effects, so its use declined as inhaled β₂-agonists became more widely used. More recently it has been shown to have anti-inflammatory effects in asthma and COPD at lower concentrations. The molecular mechanism of bronchodilatation is inhibition of phosphodiesterase(PDE)3 and PDE4, but the anti-inflammatory effect may be due to histone deacetylase (HDAC) activation, resulting in switching off of activated inflammatory genes. Through this mechanism theophylline also reverses corticosteroid resistance and this may be of particular value in severe asthma and COPD where HDAC2 activity is markedly reduced. Theophylline is given systemically (orally as slow-release preparations for chronic treatment and intravenously for acute exacerbations of asthma) and blood concentrations are determined mainly by hepatic metabolism, which may be increased or decreased in several diseases and by concomitant drug therapy. Theophylline is now usually used as an add-on therapy in asthma patients not well controlled on inhaled corticosteroids and in COPD patients with severe disease not controlled by bronchodilator therapy. Side effects are related to plasma concentrations and include nausea, vomiting and headaches due to PDE inhibition and at higher concentrations to cardiac arrhythmias and seizures due to adenosine A₁-receptor antagonism.

A meta-analysis on the efficacy of oral theophylline in patients with stable COPD

Background

Theophylline is a nonspecific inhibitor of phosphodiesterases that, despite exerting bronchodilator and anti-inflammatory effects, is a third-line therapy rarely used to treat chronic airflow limitation. We wished to evaluate the efficacy of oral theophylline as measured by improvements in trough (pre-dose) or peak (post-dose) FEV₁ and FVC in patients with clinically stable COPD.

Design

Meta-analysis of randomized, placebo-controlled trials reported as of June 2005 in which theophylline was orally administered to stable COPD patients and the functional evaluations included pre- and post-theophylline values for FEV₁ and FVC.

Results

A total of 18 trials were included in the meta-analysis. The weighted mean differences (WMD) with 95% confidence intervals (95% CI) for improvement over placebo in trough FEV₁ and FVC were 0.108L (0.053–0.163) and 0.186L (0.036–0.336), respectively, while peak FEV₁ and FVC improved by 0.096L (0.044–0.147) and 0.242L (0.11–0.374), respectively.

Conclusions

Treatment with oral theophylline improves both trough and peak FEV₁ and FVC in clinically stable COPD patients. These results support previously reported benefits of theophylline in COPD.

Stimulation of allergen-loaded macrophages by TLR9-ligand potentiates IL-10-mediated suppression of allergic airway inflammation in mice

BACKGROUND

Previously, we demonstrated that OVA-loaded macrophages (OVA-Mphi) partially suppress OVA-induced airway manifestations of asthma in BALB/c mice. In vitro studies showed that OVA-Mphi start to produce IL-10 upon interaction with allergen-specific T cells, which might mediate their immunosuppressive effects. Herein, we examined whether IL-10 is essential for the immunosuppressive effects of OVA-Mphi in vivo, and whether ex vivo stimulation of the IL-10 production by OVA-Mphi could enhance these effects.

METHODS

Peritoneal Mphi were loaded with OVA and stimulated with LPS or immunostimulatory sequence oligodeoxynucleotide (ISS-ODN) in vitro. The increase of IL-10 production was examined and, subsequently, ex vivo stimulated OVA-Mphi were used to treat (i.v.) OVA-sensitized mice. To further explore whether Mphi-derived IL-10 mediates the immunosuppressive effects, Mphi isolated from IL-10-/- mice were used for treatment.

RESULTS

We found that stimulation with LPS or ISS-ODN highly increased the IL-10 production by OVA-Mphi (2.5-fold and 4.5-fold increase, respectively). ISS-ODN stimulation of OVA-Mphi significantly potentiated the suppressive effects on allergic airway inflammation. Compared to sham-treatment, ISS-ODN-stimulated OVA-Mphi suppressed the airway eosinophilia by 85% (vs. 30% by unstimulated OVA-Mphi), IL-5 levels in bronchoalveolar lavage fluid by 80% (vs. 50%) and serum OVA-specific IgE levels by 60% (vs. 30%). Importantly, IL-10-/-Mphi that were loaded with OVA and stimulated with ISS-ODN ex vivo, failed to suppress OVA-induced airway inflammation.

CONCLUSIONS

These results demonstrate that Mphi-derived IL-10 mediates anti-inflammatory responses in a mouse model of allergic asthma, which both can be potentiated by stimulation with ISS-ODN.