Macrolides for the treatment of chronic sinusitis, asthma, and COPD

Mucoactive drugs and multiple applications in pulmonary disease therapy

Mucus is a complex polymeric hydrogel that serves as a critical defense in several organs. In the lungs, it provides a formidable barrier against inhaled particles such as microorganisms. In addition, mucus is essential for normal lung physiology, as it promotes immune tolerance and facilitates a normal commensal pulmonary microbiome. Hypersecretion of airway mucus is a characteristic of numerous respiratory diseases, such as Chronic Obstructive Pulmonary Disease (COPD) and Cystic Fibrosis (CF), and creates pulmonary obstruction, limiting the effectiveness of inhaled therapies. Due to those alterations, therapeutic strategies must be optimal to limit airway obstruction and restore pulmonary function. Mucoactive drugs are common therapeutic options and are classified into different groups depending on their modes of action, i.e., expectorants, mucokinetics, mucoregulators and mucolytics. This review focuses on mucoactive drugs and their modes of action. A special focus will be made on two challenging pulmonary pathologies: COPD and CF, and on their clinical studies conducted with mucoactive drugs.

Pleiotropic effects of antibiotics on T cell metabolism and T cell-mediated immunity

T cells orchestrate adaptive and innate immune responses against pathogens and transformed cells. However, T cells are also the main adaptive effector cells that mediate allergic and autoimmune reactions. Within the last few years, it has become abundantly clear that activation, differentiation, effector function, and environmental adaptation of T cells is closely linked to their energy metabolism. Beyond the provision of energy equivalents, metabolic pathways in T cells generate building blocks required for clonal expansion. Furthermore, metabolic intermediates directly serve as a source for epigenetic gene regulation by histone and DNA modification mechanisms. To date, several antibiotics were demonstrated to modulate the metabolism of T cells especially by altering mitochondrial function. Here, we set out to systematically review current evidence about how beta-lactam antibiotics, macrolides, fluoroquinolones, tetracyclines, oxazolidinones, nitroimidazoles, and amphenicols alter the metabolism and effector functions of CD4+ T helper cell populations and CD8+ T cells in vitro and in vivo. Based on this evidence, we have developed an overview on how the use of these antibiotics may be beneficial or detrimental in T cell-mediated physiological and pathogenic immune responses, such as allergic and autoimmune diseases, by altering the metabolism of different T cell populations.

Pharmacokinetic study of clarithromycin in human breast milk by UPLC-MS/MS

This study aimed to develop a validated UPLC-MS/MS method for pharmacokinetic analysis of clarithromycin in human breast milk. For sample preparation, proteins precipitated with methanol and azithromycin were used as internal standards. Clarithromycin and azithromycin detection was achieved using electrospray ionization in positive mode. The chromatographic separation time was 5 min. The lower limit of quantification was 50 ng/mL. The calibration curve of clarithromycin was 50-4000 ng/mL, with a correlation coefficient> 0.99. The method was successfully applied to determine clarithromycin levels in breast milk obtained from a lactating mother after oral administration of a single tablet containing 500 mg of clarithromycin. The maximum human breast milk concentration (C_max) was 3660 ng/mL, the time to reach the maximum concentration (t_max) was 2.5 h, and the area under curve (AUC_0-24) was 18450 ng h/mL. The present study provides a novel UPLC-MS/MS method for pharmacokinetic analysis of clarithromycin in breast milk.

Differential Expression Study of Lysine Crotonylation and Proteome for Chronic Obstructive Pulmonary Disease Combined with Type II Respiratory Failure

Introduction

The modification of lysine crotonylation (Kcr) is another biological function of histone in addition to modification of lysine acetylation (Kac), which may play a specific regulatory role in diseases.

Objectives

This study compared the expression levels of Kcr and proteome between patients with chronic obstructive pulmonary disease (COPD) combined with type II respiratory failure (RF) to study the relationship between Kcr, proteome, and COPD.

Methods

We tested the Kcr and proteome of COPD combined with type II RF and normal control (NC) using croton acylation enrichment technology and liquid chromatography tandem mass spectrometry (LC-MS/MS) with high resolution.

Results

We found that 32 sites of 23 proteins were upregulated and 914 sites of 295 proteins were downregulated. We performed Kyoto Encyclopedia of Genes and Genomes (KEGG), protein domain, and Gene Ontology (GO) analysis on crotonylated protein. In proteomics research, we found that 190 proteins were upregulated and 151 proteins were downregulated. Among them, 90 proteins were both modified by differentially expressed crotonylation sites and differentially expressed in COPD combined with type II RF and NC.

Conclusion

Differentially expressed crotonylation sites may be involved in the development of COPD combined with type II RF. 90 proteins modified by crotonylation and differentially expressed in COPD combined with type II RF can be used as markers for the study of the molecular pathogenesis of COPD combined with type II RF.

Drug repurposing approach to combating coronavirus: Potential drugs and drug targets

In the past two decades, three highly pathogenic human coronaviruses severe acute respiratory syndrome coronavirus (SARS-CoV), Middle East respiratory syndrome coronavirus, and, recently, SARS-CoV-2, have caused pandemics of severe acute respiratory diseases with alarming morbidity and mortality. Due to the lack of specific anti-CoV therapies, the ongoing pandemic of coronavirus disease 2019 (COVID-19) poses a great challenge to clinical management and highlights an urgent need for effective interventions. Drug repurposing is a rapid and feasible strategy to identify effective drugs for combating this deadly infection. In this review, we summarize the therapeutic CoV targets, focus on the existing small molecule drugs that have the potential to be repurposed for existing and emerging CoV infections of the future, and discuss the clinical progress of developing small molecule drugs for COVID-19.

Inhaled RNA Therapeutics for Obstructive Airway Diseases: Recent Advances and Future Prospects

Obstructive airway diseases, e.g., chronic obstructive pulmonary disease (COPD) and asthma, represent leading causes of morbidity and mortality worldwide. However, the efficacy of currently available inhaled therapeutics is not sufficient for arresting disease progression and decreasing mortality, hence providing an urgent need for development of novel therapeutics. Local delivery to the airways via inhalation is promising for novel drugs, because it allows for delivery directly to the target site of action and minimizes systemic drug exposure. In addition, novel drug modalities like RNA therapeutics provide entirely new opportunities for highly specific treatment of airway diseases. Here, we review state of the art of conventional inhaled drugs used for the treatment of COPD and asthma with focus on quality attributes of inhaled medicines, and we outline the therapeutic potential and safety of novel drugs. Subsequently, we present recent advances in manufacturing of thermostable solid dosage forms for pulmonary administration, important quality attributes of inhalable dry powder formulations, and obstacles for the translation of inhalable solid dosage forms to the clinic. Delivery challenges for inhaled RNA therapeutics and delivery technologies used to overcome them are also discussed. Finally, we present future prospects of novel inhaled RNA-based therapeutics for treatment of obstructive airways diseases, and highlight major knowledge gaps, which require further investigation to advance RNA-based medicine towards the bedside.

The effects of macrolides in children with reactive airway disease: a systematic review and meta-analysis of randomized controlled trials

Purpose

Childhood reactive airway diseases (RADs) are concerning problems in children’s airways and may be preceded by bronchiolitis and may progress to childhood asthma. The severity of the disease is indicated by deterioration in pulmonary functions, increased usage of rescue medications, and recurrent wheezing episodes. Macrolides have both antimicrobial and anti-inflammatory functions and have been used as adjunctive therapy in childhood RADs.

Patients and methods

We conducted a meta-analysis to evaluate the effect of macrolides in children with RAD. Literature searches were systematically conducted using an electronic database from inception to August 2018. The Cochrane review risk of bias assessment tool was used to assess the quality of each randomized controlled trial.

Results

Sixteen randomized controlled trials comprising 1,415 participants were investigated in this meta-analysis. Children treated with macrolide therapy showed significantly better pulmonary functions in both forced expiratory volume in one second (% predicted) (difference in means=−9.77, 95% CI=−14.18 to −5.35, P<0.001; I²=0%) and forced expiratory flow 25–75 (% predicted) (difference in means=−14.14, 95% CI=−26.11 to −2.18, P=0.02; I²=29.56%). In addition, the short-acting β-agonist usage days and recurrent wheezing risk were significantly lowered in children with macrolide treatment (standardized difference in means=−0.34, 95% CI=−0.59 to −0.09, P=0.007, I²=27.05% and standardized difference in means=−0.53, 95% CI=−0.81 to −0.26, P<0.001, I²=0%, respectively). Furthermore, the growth of Moraxella catarrhalis from nasal swabs was less in children treated with macrolides (odds ratio=0.19, 95% CI=0.11–0.35, P<0.001). Children who took macrolides had a lower risk of adverse events (risk ratio=0.83, 95% CI=0.70–0.98, P=0.024, I²=0%).

Conclusion

This current meta-analysis suggested that adjunctive therapy with macrolides is safe and effective for achieving better outcomes in childhood RAD.

Understanding the Impacts of Surface Compositions on the In-Vitro Dissolution and Aerosolization of Co-Spray-Dried Composite Powder Formulations for Inhalation

PURPOSE

Dissolution behavior of dry powder inhaler (DPI) antibiotic formulations in the airways may affect their efficacy especially for poorly-soluble antibiotics such as azithromycin. The main objective of this study was to understand the effects of surface composition on the dissolution of spray dried azithromycin powders by itself and in combination with colistin.

METHODS

Composite formulations of azithromycin (a poorly water-soluble molecule) and colistin (a water-soluble molecule) were produced by spray drying. The resultant formulations were characterized for particle size, morphology, surface composition, solid-state properties, solubility and dissolution.

RESULTS

The results demonstrate that surfaces composition has critical impacts on the dissolution of composite formulations. Colistin was shown to increase the solubility of azithromycin. For composite formulations with no surface colistin, azithromycin released at a similar dissolution rate as the spray-dried azithromycin alone. An increase in surface colistin concentration was shown to accelerate the dissolution of azithromycin. The dissolution of colistin from the composite formulations was significantly slower than the spray-dried pure colistin. In addition, FTIR spectrum showed intermolecular interactions between azithromycin and colistin in the composite formulations, which could contribute to the enhanced solubility and dissolution of azithromycin.

CONCLUSIONS

Our study provides fundamental understanding of the effects of surface concentration of colistin on azithromycin dissolution of co-spray-dried composite powder formulations.

Low concentrations of clarithromycin upregulate cellular antioxidant enzymes and phosphorylation of extracellular signal-regulated kinase in human small airway epithelial cells

BACKGROUND

It is well known that low-dose, long-term macrolide therapy is effective against chronic inflammatory airway diseases. Oxidative stress is considered to be a key pathogenesis factor in those diseases. However, the mechanism of action of low-dose, long-term macrolide therapy remains unclear. We have reported that clarithromycin (CAM), which is a representative macrolide antibiotic, could inhibit hydrogen peroxide (H2O2)-induced reduction of the glutathione (GSH)/glutathione disulfide (GSSG) ratio in human small airway epithelial cells (SAECs), via the maintenance of GSH levels through an effect on γ-glutamylcysteine synthetase (γ-GCS) expression. In this study, we examined the influence of CAM against H2O2-induced activities of cellular antioxidant enzymes and phosphorylated extracellular signal regulatory kinase (p-ERK) using SAECs, the main cells involved in chronic airway inflammatory diseases.

METHODS

SAECs were pretreated with CAM (1, 5, and 10 μM) for 72 h, and subsequently exposed to H2O2 (100 μM) for 0.5-2 h. Levels of GSH and GSSG, and activities of glutathione peroxidase (GPx)-1, glutathione reductase (GR), superoxide dismutase (SOD), catalase (CAT), heme oxygenase (HO)-1 and p-ERK were assayed. mRNA expressions of GPx-1 and HO-1 were measured using the real-time reverse transcription polymerase chain reaction (RT-PCR). Tukey's multiple comparison test was used for analysis of statistical significance.

RESULTS

Pretreatment with low-dose (1 and 5 μM) CAM for 72 h inhibited H2O2-induced reductions of GPx-1, GR, SOD, CAT and HO-1 activities, and mRNA expressions of GPx-1 and HO-1, and improved the GSH/GSSG ratio. However, these alterations were not observed after pretreatment with high-dose (10 μM) CAM, which suppressed phosphorylation of cell proliferation-associated ERK to cause a significant (p < 0.01) decrease in cell viability.

CONCLUSIONS

CAM is efficacious against deterioration of cellular antioxidant enzyme activity caused by oxidative stress under low-dose, long-term treatment conditions. On the other hand, pretreatment with high-dose CAM suppressed phosphorylation of cell proliferation-associated ERK and decreased cell viability. The present study may provide additional evidence as to why low-dose, long-term administration of macrolides is effective for treating chronic inflammatory airway diseases.

Diffuse maculopapular exanthema and a positive lymphocyte transformation test reaction in response to clarithromycin

Macrolides are one of the most widely used antibiotics, but the mechanisms underlying macrolide allergy have not been clearly elucidated. Diffuse maculopapular exanthema caused by clarithromycin is extremely rare, of which clinical images have not been reported. Here, we report a case of a 55-year-old Japanese female who was treated with oral clarithromycin and lysozyme hydrochloride due to odontogenic maxillary sinusitis. On the 15th day after starting both drugs, she suffered from diffuse maculopapular exanthema, which worsened despite the discontinuation of lysozyme hydrochloride and the introduction of treatment with oral and topical corticosteroids and oral levocetirizine. Clarithromycin was discontinued and an intravenous corticosteroid introduced on the 19th day. A lymphocyte transformation test was positive for clarithromycin but negative for lysozyme hydrochloride. Although adverse effects of clarithromycin are extremely rare, physicians should be aware of clarithromycin as a potential cause of a type IV allergic reaction.

Physico-Chemical Properties, Aerosolization and Dissolution of Co-Spray Dried Azithromycin Particles with L-Leucine for Inhalation

PURPOSE

Inhalation therapy is popular to treat lower respiratory tract infections. Azithromycin is effective against some bacteria that cause respiratory tract infections; but it has poor water solubility that may limit its efficacy when administrated as inhalation therapy. In this study, dry powder inhaler formulations were developed by co-spray drying azithromycin with L-leucine with a purpose to improve dissolution.

METHODS

The produced powder formulations were characterized regarding particle size, morphology, surface composition and in-vitro aerosolization performance. Effects of L-leucine on the solubility and in-vitro dissolution of azithromycin were also evaluated.

RESULTS

The spray dried azithromycin alone formulation exhibited a satisfactory aerosol performance with a fine particle fraction (FPF) of 62.5 ± 4.1%. Addition of L-leucine in the formulation resulted in no significant change in particle morphology and FPF, which can be attributed to enrichment of azithromycin on the surfaces of composite particles. Importantly, compared with the spray-dried amorphous azithromycin alone powder, the co-spray dried powder formulations of azithromycin and L-leucine demonstrated a substantially enhanced in-vitro dissolution rate. Such enhanced dissolution of azithromycin could be attributed to the formation of composite system and the acidic microenvironment around azithromycin molecules created by the dissolution of acidic L-leucine in the co-spray dried powder. Fourier transform infrared spectroscopic data showed intermolecular interactions between azithromycin and L-leucine in the co-spray dried formulations.

CONCLUSIONS

We developed the dry powder formulations with satisfactory aerosol performance and enhanced dissolution for a poorly water soluble weak base, azithromycin, by co-spray drying with an amino acid, L-leucine.

Long-term treatment of clarithromycin at a low concentration improves hydrogen peroxide-induced oxidant/antioxidant imbalance in human small airway epithelial cells by increasing Nrf2 mRNA expression

Background

Clarithromycin (CAM), a representative macrolide antibiotic, has been used widely at low doses for long-term therapy of chronic inflammatory airway diseases. Anti-inflammatory effects of macrolide antibiotics were first discovered in clinical practice. Although oxidative stress is known as a key pathogenesis factor in chronic airway inflammatory diseases, the mechanism of action of low-dose, long-term CAM therapy remains unclear. We aimed to examine the cytoprotective action of CAM against hydrogen peroxide (H₂O₂)-induced cell dysfunction, focusing on CAM dose and treatment duration, and using human small airway epithelial cells (SAECs), the main cells involved in chronic airway inflammatory diseases.

Methods

SAECs were pretreated with CAM (1, 5 or 10 μM) for 24, 48 or 72 h, and were subsequently exposed to H₂O₂ for 0.5–4 h. Levels of interleukin (IL)-8, glutathione (GSH) and glutathione disulfide (GSSG), and the activities of nuclear factor (NF)-κB and γ-glutamylcysteine synthetase (γ-GCS) were assayed using specific methods. IL-8 mRNA and NF erythroid 2-related factor 2 (Nrf2) mRNA expression were measured using real-time reverse transcription polymerase chain reaction (RT-PCR). Tukey’s multiple comparison test was used for analysis of statistical significance.

Results

Pretreatment with low-dose (1 or 5 μM), long-term (72 h) CAM inhibited H₂O₂-induced IL-8 levels, NF-κB activity, and IL-8 mRNA expression, and improved the GSH/GSSG ratio via the maintenance of γ-GCS expression levels. Similar to its enhancing effect on the GSH/GSSG ratio, pretreatment with low-dose CAM for 72 h significantly increased Nrf2 mRNA expression (p < 0.01 and p < 0.05). In contrast, these alterations were not observed after pretreatment with high-dose (10 μM) or short-term (24 and 48 h) CAM.

Conclusions

CAM is efficacious against cell dysfunction caused by oxidative stress under low-dose, long-term treatment conditions. This effect depended on the suppression of NF-κB activation and improvement of the H₂O₂-induced oxidant/antioxidant imbalance that is achieved by increasing Nrf2 mRNA expression in SAECs. The present study may provide the first evidence of why low-dose, long-term administration of macrolides is effective for treating chronic inflammatory airway diseases.

Electronic supplementary material

The online version of this article (doi:10.1186/s40360-017-0119-8) contains supplementary material, which is available to authorized users.

Predicting postoperative fever and bacterial colonization on packing material following endoscopic endonasal surgery

Postoperative fever following endoscopic endonasal surgery is a rare occurrence of concern to surgeons. To elucidate preoperative and operative predictors of postoperative fever, we analyzed the characteristics of patients and their perioperative background in association with postoperative fever. A retrospective review of 371 patients who had undergone endoscopic endonasal surgery was conducted. Predictors, including intake of antibiotics, steroids, history of asthma, preoperative nasal bacterial culture, duration of operation, duration of packing and intraoperative intravenous antibiotics on the occurrence of postoperative fever, and bacterial colonization on the packing material, were analyzed retrospectively. Fever (≥38 °C) occurred in 63 (17 %) patients. Most incidences of fever occurred on postoperative day one. In majority of these cases, the fever subsided after removal of the packing material without further antibiotic administration. However, one patient who experienced persistent fever after the removal of packing material developed meningitis. History of asthma, prolonged operation time (≥108 min), and intravenous cefazolin administration instead of cefmetazole were associated with postoperative fever. Odds ratios (ORs) for each were 2.3, 4.6, and 2.0, respectively. Positive preoperative bacterial colonization was associated with postoperative bacterial colonization on the packing material (OR 2.3). Postoperative fever subsided in most patients after removal of the packing material. When this postoperative fever persists, its underlying cause should be examined.

A Compendium for Mycoplasma pneumoniae

Historically, atypical pneumonia was a term used to describe an unusual presentation of pneumonia. Currently, it is used to describe the multitude of symptoms juxtaposing the classic symptoms found in cases of pneumococcal pneumonia. Specifically, atypical pneumonia is a syndrome resulting from a relatively common group of pathogens including Chlamydophila sp., and Mycoplasma pneumoniae. The incidence of M. pneumoniae pneumonia in adults is less than the burden experienced by children. Transmission rates among families indicate children may act as a reservoir and maintain contagiousness over a long period of time ranging from months to years. In adults, M. pneumoniae typically produces a mild, “walking” pneumonia and is considered to be one of the causes of persistent cough in patients. M. pneumoniae has also been shown to trigger the exacerbation of other lung diseases. It has been repeatedly detected in patients with bronchitis, asthma, chronic obstructive pulmonary disorder, and cystic fibrosis. Recent advances in technology allow for the rapid diagnosis of M. pneumoniae through the use of polymerase chain reaction or rapid antigen tests. With this, more effort has been afforded to identify the causative etiologic agent in all cases of pneumonia. However, previous practices, including the overprescribing of macrolide treatment in China and Japan, have created increased incidence of macrolide-resistant M. pneumoniae. Reports from these countries indicate that >85% of M. pneumoniae pneumonia pediatric cases are macrolide-resistant. Despite its extensively studied past, the smallest bacterial species still inspires some of the largest questions. The developments in microbiology, diagnostic features and techniques, epidemiology, treatment and vaccines, and upper respiratory conditions associated with M. pneumoniae in adult populations are included within this review.

Identification of Onodi cell and new classification of sphenoid sinus for endoscopic sinus surgery

BACKGROUND

There is no effective classification method for the opening of the sphenoid sinus. The objective of this study was to examine the effectiveness of identification of the Onodi cell and classification of the sphenoid sinus using sagittal computed tomography (CT) for sphenoidotomy.

METHODS

CT images of the sinuses of surgical patients (n = 261; 522 sides) were studied. Using sagittal CT, the relationships between the lateral side of the anterior wall of the sphenoid sinus and the optic nerve, and between the middle of the anterior wall of the sphenoid sinus and the skull base or pituitary gland were studied. Images were classified as demonstrating skull base (without the Onodi cell), optic canal, sella, or infra-sella (all with the Onodi cell) type.

RESULTS

Two hundred and fifty-eight sides (49.2%) were of the skull-base type, 181 (34.7%) were of the optic-canal type, 58 (11.1%) were of the sella type, and 26 (5.0%) were of the infra-sella type; ie, the Onodi cell was present in 50.8% of sides. The width of the anterior wall of the sphenoid sinus became narrower as it shifted from the skull-base type to the infra-sella type.

CONCLUSION

Classification of the anterior wall of the sphenoid sinus based on the Onodi cell allows 3-dimensional assessment of the shape of the sphenoid sinus. We believe that the sphenoid sinus can be opened safely by full preoperative assessment of the anterior wall type, the position of the superior turbinate, and the position of the ostium of the sphenoid sinus.

Effect of azithromycin on the LPS-induced production and secretion of phospholipase A2 in lung cells

Azithromycin is a member of macrolides, utilized in the treatment of infections. Independently, these antibiotics also possess anti-inflammatory and immunomodulatory properties. Phospholipase A2 isotypes, which are implicated in the pathophysiology of inflammatory lung disorders, are produced by alveolar macrophages and other lung cells during inflammatory response and can promote lung injury by destructing lung surfactant. The aim of the study was to investigate whether in lung cells azithromycin can inhibit secretory and cytosolic phospholipases A2, (sPLA2) and (cPLA2), respectively, which are induced by an inflammatory trigger. In this respect, we studied the lipopolysaccharide (LPS)-mediated production or secretion of sPLA2 and cPLA2 from A549 cells, a cancer bronchial epithelial cell line, and alveolar macrophages, isolated from bronchoalveolar lavage fluid of ARDS and control patients without cardiopulmonary disease or sepsis. Pre-treatment of cells with azithromycin caused a dose-dependent decrease in the LPS-induced sPLA2-IIA levels in A549 cells. This inhibition was rather due to reduced PLA2G2A mRNA expression and secretion of sPLA2-IIA protein levels, as observed by western blotting and indirect immunofluorescence by confocal microscopy, respectively, than to the inhibition of the enzymic activity per se. On the contrary, azithromycin had no effect on the LPS-induced production or secretion of sPLA2-IIA from alveolar macrophages. The levels of LPS-induced c-PLA2 were not significantly affected by azithromycin in either cell type. We conclude that azithromycin exerts anti-inflammatory properties on lung epithelial cells through the inhibition of both the expression and secretion of LPS-induced sPLA2-IIA, while it does not affect alveolar macrophages.

Azithromycin suppresses CD4(+) T-cell activation by direct modulation of mTOR activity

Advanced macrolides, such as azithromycin (AZM) or clarithromycin (CLM), are antibiotics with immunomodulatory properties. Here we have sought to evaluate their in vitro influence on the activation of CD4(+) T-cells. Isolated CD4(+) T-cells were stimulated with agonistic anti-CD3/anti-CD28 monoclonal antibodies in the presence of 0.6 mg/L, 2.5 mg/L, 10 mg/L or 40 mg/L AZM or CLM. Cell proliferation, cytokine level in supernatants and cell viability was assessed. Intracellular signaling pathways were evaluated using reporter cell lines, FACS analysis, immunoblotting and in vitro kinase assays. AZM inhibited cell proliferation rate and cytokine secretion of CD4(+) T-cells in a dose-dependent manner. Similarly, high concentrations of CLM (40 mg/L) also suppressed these T-cell functions. Analysis of molecular signaling pathways revealed that exposure to AZM reduced the phosphorylation of the S6 ribosomal protein, a downstream target of mTOR. This effect was also observed at 40 mg/L CLM. In vitro kinase studies using recombinant mTOR showed that AZM inhibited mTOR activity. In contrast to rapamycin, this inhibition was independent of FKBP12. We show for the first time that AZM and to a lesser extent CLM act as immunosuppressive agents on CD4(+) T-cells by inhibiting mTOR activity. Our results might have implications for the clinical use of macrolides.

Chronic rhinosinusitis and antibiotics: the good, the bad, and the ugly

BACKGROUND

Despite the recognition that bacteria are universally present in the sinuses of patients with chronic rhinosinusitis (CRS) no compelling role for a primary infectious etiology of CRS has been elucidated. CRS is a constellation of inflammatory diseases that typically involve either noneosinophilic or eosinophilic processes, distinct conditions that must be treated individually.

METHODS

The bacteria that are present in the sinuses may be innocuous bystanders but alternatively may contribute to the presence and severity of the disease through their ability to influence immune responses, function as immune adjuvants, provide antigens or superantigens that contribute to adaptive immune activation, or in forming the basis for the frequent acute superinfections. However, those bacteria that do contribute to the persistence and severity of CRS primarily reside in biofilms, and, as such, are not capable of being eradicated with antibiotics at the doses at which they can be used, even when local irrigation is considered.

RESULTS

Biofilms create an inhospitable environment for antibiotic potency by down-regulating the metabolic activity of their "core" bacteria, decreasing the oxygen concentration, and altering the pH at the core of the biofilm.

CONCLUSION

Ultimately, if topical antibiotics are considered, they should be primarily focused on treating acute exacerbations and choices of antibiotics should optimally be based on endoscopic culture. This should be done with the recognition that while under certain circumstances antibiotics can ameliorate the severity of CRS, even if bacterial eradication were possible, this would not eliminate the underlying primary pathogenic mechanism or the natural history of these conditions.

Effects of erythromycin on γ-glutamyl cysteine synthetase and interleukin-1β in hyperoxia-exposed lung tissue of premature newborn rats

OBJECTIVE

To explore the effect of erythromycin on hyperoxia-induced lung injury.

METHODS

One-day-old preterm offspring Sprague-Dawley (SD) rats were randomly divided into four groups: group 1, air + sodium chloride; group 2, air + erythromycin;group 3, hyperoxia + sodium chloride; and group 4, hyperoxia + erythromycin. At one, seven, and 14 days of exposure, glutathione (GSH) and interleukin-1 beta (IL-1 beta) were detected by double-antibody sandwich enzyme-linked immunosorbent assay (ELISA), and bicinchoninic acid (BCA) was used to detect GSH protein. γ-glutamine-cysteine synthetase (γ-GCS) mRNA was detected by reverse transcription-polymerase chain reaction (RT-PCR).

RESULTS

Compared with group 1, expressions of GSH and γ-GCS mRNA in group 3 were significantly increased at one and seven days of exposure (p < 0.05), but expression of γ-GCS mRNA was significantly reduced at 14 days; expression of IL-1 beta in group 3 was significantly increased at seven days of exposure (p < 0.05), and was significantly reduced at 14 days. Compared with group 3, expressions of GSH and γ-GCS mRNA in group 4 were significantly increased at one, seven, and 14 days of exposure (p < 0.05), but expressions of GSH showed a downward trend at 14 days; expression of IL-1 beta in group 4 was significantly reduced at one and seven days of exposure (p < 0.05).

CONCLUSIONS

Changes in oxidant-mediated IL-1 beta and GSH are involved in the development of hyperoxia-induced lung injury. Erythromycin may up-regulate the activity of γ-GCS, increasing the expression of GSH, inhibiting the levels of oxidant-mediated IL-1 beta and alleviating hyperoxia-induced lung injury via an antioxidant effect.

Population pharmacokinetics of azithromycin in whole blood, peripheral blood mononuclear cells, and polymorphonuclear cells in healthy adults

Azithromycin's extensive distribution to proinflammatory cells, including peripheral blood mononuclear cells (PBMCs) and polymorphonuclear cells (PMNs), may be important to its antimicrobial and anti-inflammatory properties. The need to simultaneously predict azithromycin concentrations in whole blood ("blood"), PBMCs, and PMNs motivated this investigation. A single-dose study in 20 healthy adults was conducted, and nonlinear mixed effects modeling was used to simultaneously describe azithromycin concentrations in blood, PBMCs, and PMNs (simultaneous PK model). Data were well described by a four-compartment mamillary model. Apparent central clearance and volume of distribution estimates were 67.3 l/hour and 336 l (interindividual variability of 114 and 122%, respectively). Bootstrapping and visual predictive checks showed adequate model performance. Azithromycin concentrations in blood, PBMCs, and PMNs from external studies of healthy adults and cystic fibrosis patients were within the 5th and 95th percentiles of model simulations. This novel empirical model can be used to predict azithromycin concentrations in blood, PBMCs, and PMNs with different dosing regimens.

Clinical issues of mucus accumulation in COPD

Airway mucus is part of the lung's native immune function that traps particulates and microorganisms, enabling their clearance from the lung by ciliary transport and cough. Mucus hypersecretion and chronic productive cough are the features of the chronic bronchitis and chronic obstructive pulmonary disease (COPD). Overproduction and hypersecretion by goblet cells and the decreased elimination of mucus are the primary mechanisms responsible for excessive mucus in chronic bronchitis. Mucus accumulation in COPD patients affects several important outcomes such as lung function, health-related quality of life, COPD exacerbations, hospitalizations, and mortality. Nonpharmacologic options for the treatment of mucus accumulation in COPD are smoking cessation and physical measures used to promote mucus clearance. Pharmacologic therapies include expectorants, mucolytics, methylxanthines, beta-adrenergic receptor agonists, anticholinergics, glucocorticoids, phosphodiesterase-4 inhibitors, antioxidants, and antibiotics.

Alternaria inhibits double-stranded RNA-induced cytokine production through Toll-like receptor 3

BACKGROUND

Fungi may be involved in asthma and chronic rhinosinusitis (CRS). Peripheral blood mononuclear cells from CRS patients produce interleukin (IL)-5, IL-13 and interferon (IFN)-γ in the presence of Alternaria. In addition, Alternaria produces potent Th2-like adjuvant effects in the airway. Therefore, we hypothesized that Alternaria may inhibit Th1-type defense mechanisms against virus infection.

METHODS

Dendritic cells (DCs) were generated from mouse bone marrow. The functional responses were assessed by expression of cell surface molecules by FACS (MHC class II, CD40, CD80, CD86 and OX40L). Production of IL-6, chemokine CXCL10 (IP-10), chemokine CXCL11 (I-TAC) and IFN-β was measured by ELISA. Toll-like receptor 3 (TLR3) mRNA and protein expression was detected by quantitative real-time PCR and Western blot.

RESULTS

Alternaria and polyinosinic-polycytidylic acid (poly I:C) enhanced cell surface expression of MHC class II, CD40, CD80, CD86 and OX40L, and IL-6 production in a concentration-dependent manner. However, Alternaria significantly inhibited production of IP-10, I-TAC and IFN-β, induced by viral double-stranded RNA (dsRNA) mimic poly I:C. TLR3 mRNA expression and protein production by poly I:C were significantly inhibited by Alternaria. These reactions are likely caused by heat-stable factor(s) in Alternaria extract with >100 kDa molecular mass.

CONCLUSION

These findings suggest that the fungus Alternaria may inhibit production of IFN-β and other cytokines by DCs by suppressing TLR3 expression. These results indicate that Alternaria may inhibit host innate immunity against virus infection.

Physicochemical aspects of the coformulation of colistin and azithromycin using liposomes for combination antibiotic therapies

Remote loading of azithromycin into liposomes, and subsequent release behavior in the presence of colistin, has been investigated with a view to understand the potential of liposomes to enable the coformulation of these two antibiotics for application in inhalation therapy. Azithromycin was successfully encapsulated into liposomes by remote loading (encapsulation efficiency > 98%). Slow release of azithromycin was achieved in the presence of cholesterol in a concentration-dependent manner, with a 4:1 mol ratio of phospholipid-cholesterol releasing 22% azithromycin in 24 h, whereas a 2:1 mol ratio released only 4.9% of azithromycin in 24 h. Addition of colistin to the formulation with increasing concentration did not change the loading behavior, but accelerated drug release, increasing the percentage of released azithromycin from 4.9% to 30% over 24 h. The permeabilizing ability of colistin on liposomes is consistent with its permeabilizing effect on bacterial cells. This behavior opens opportunities to tailor the release rate of drugs coformulated with colistin using liposomes as the carrier.

Chronic bronchitis and chronic obstructive pulmonary disease

Chronic bronchitis (CB) is a common but variable phenomenon in chronic obstructive pulmonary disease (COPD). It has numerous clinical consequences, including an accelerated decline in lung function, greater risk of the development of airflow obstruction in smokers, a predisposition to lower respiratory tract infection, higher exacerbation frequency, and worse overall mortality. CB is caused by overproduction and hypersecretion of mucus by goblet cells, which leads to worsening airflow obstruction by luminal obstruction of small airways, epithelial remodeling, and alteration of airway surface tension predisposing to collapse. Despite its clinical sequelae, little is known about the pathophysiology of CB and goblet cell hyperplasia in COPD, and treatment options are limited. In addition, it is becoming increasingly apparent that in the classic COPD spectrum, with emphysema on one end and CB on the other, most patients lie somewhere in the middle. It is known now that many patients with severe emphysema can develop CB, and small airway pathology has been linked to worse clinical outcomes, such as increased mortality and lesser improvement in lung function after lung volume reduction surgery. However, in recent years, a greater understanding of the importance of CB as a phenotype to identify patients with a beneficial response to therapy has been described. Herein we review the epidemiology of CB, the evidence behind its clinical consequences, the current understanding of the pathophysiology of goblet cell hyperplasia in COPD, and current therapies for CB.

Evaluation of subgingivally delivered 0.5% clarithromycin as an adjunct to nonsurgical mechanotherapy in the management of chronic periodontitis: a short-term double blinded randomized control trial

OBJECTIVE

As the risk involved with systemic antimicrobials (high doses, microbial resistance, adverse reactions, etc.) restricts their use and local delivery of antimicrobials into periodontal pockets improves periodontal health, this study was designed to investigate the effects of subgingivally delivered clarithromycin (CLM; 0.5%) as an adjunct to nonsurgical mechanotherapy in chronic periodontitis subjects.

METHODS

Ninety-eight patients were categorized into two treatment groups: scaling and root planing (SRP) plus 0.5% CLM (test; group 1) and SRP plus placebo (control; group 2). Clinical parameters included gingival index (GI), sulcus bleeding index (SBI), plaque index (PI), probing depth (PD), and periodontal attachment level (PAL), recorded at 4, 8 and 12 weeks. The concentration of 0.5% CLM in gingival fluid was estimated by reverse-phase high pressure liquid chromatography. anova, the chi-square test and the Scatterthwaite test were used for statistical analysis.

RESULTS

Patients treated with SRP + CLM showed enhanced reductions in GI, SBI, and PD, and gains in PAL (P < 0.001) over time, as compared with the placebo group. However, no statistically significant differences were noted for PI. The mean concentration of CLM was detected in gingival crevicular fluid for up to 7 weeks, fulfilling the conditions for a controlled-release device.

CONCLUSION

Adjunctive use of 0.5% CLM as a controlled drug delivery system enhanced the clinical outcome up to 3 months.

Azithromycin distinctively modulates classical activation of human monocytes in vitro

BACKGROUND AND PURPOSE

Azithromycin has been reported to modify activation of macrophages towards the M2 phenotype. Here, we have sought to identify the mechanisms underlying this modulatory effect of azithromycin on human monocytes, classically activated in vitro.

EXPERIMENTAL APPROACH

Human blood monocytes were primed with IFN-γ for 24 h and activated with LPS for 24 h. Azithromycin, anti-inflammatory and lysosome-affecting agents were added 2 h before IFN-γ. Cytokine and chemokine expression was determined by quantitative PCR and protein release by ELISA. Signalling molecules were determined by Western blotting and transcription factor activation quantified with a DNA-binding ELISA kit.

KEY RESULTS

Azithromycin (1.5-50 µM) dose-dependently inhibited gene expression and/or release of M1 macrophage markers (CCR7, CXCL 11 and IL-12p70), but enhanced CCL2, without altering TNF-α or IL-6. Azithromycin also enhanced the gene expression and/or release of M2 macrophage markers (IL-10 and CCL18), and the pan-monocyte marker CD163, but inhibited that of CCL22. The Toll-like receptor (TLR) 4 signalling pathway was modulated, down-regulating NF-κB and STAT1 transcription factors. The inhibitory profile of azithromycin differed from that of dexamethasone, the phosphodiesterase-4 inhibitor roflumilast and the p38 kinase inhibitor SB203580 but was similar to that of the lysosomotropic drug chloroquine. Effects of concanamycin and NH4Cl, which also act on lysosomes, differed significantly.

CONCLUSIONS AND IMPLICATIONS

Azithromycin modulated classical activation of human monocytes by inhibition of TLR4-mediated signalling and possible effects on lysosomal function, and generated a mediator expression profile that differs from that of monocyte/macrophage phenotypes so far described.

Pathogen- and host-directed anti-inflammatory activities of macrolide antibiotics

Macrolide antibiotics possess several, beneficial, secondary properties which complement their primary antimicrobial activity. In addition to high levels of tissue penetration, which may counteract seemingly macrolide-resistant bacterial pathogens, these agents also possess anti-inflammatory properties, unrelated to their primary antimicrobial activity. Macrolides target cells of both the innate and adaptive immune systems, as well as structural cells, and are beneficial in controlling harmful inflammatory responses during acute and chronic bacterial infection. These secondary anti-inflammatory activities of macrolides appear to be particularly effective in attenuating neutrophil-mediated inflammation. This, in turn, may contribute to the usefulness of these agents in the treatment of acute and chronic inflammatory disorders of both microbial and nonmicrobial origin, predominantly of the airways. This paper is focused on the various mechanisms of macrolide-mediated anti-inflammatory activity which target both microbial pathogens and the cells of the innate and adaptive immune systems, with emphasis on their clinical relevance.

Comprehensive Analysis of Bacterial Flora in Postoperative Maxillary Cyst Fluid by 16S rRNA Gene and Culture Methods

Intracystic fluid was aseptically collected from 11 patients with postoperative maxillary cyst (POMC), and DNA was extracted from the POMC fluid. Bacterial species were identified by sequencing after cloning of approximately 580 bp of the 16S rRNA gene. Identification of pathogenic bacteria was also performed by culture methods. The phylogenetic identity was determined by sequencing 517–596 bp in each of the 1139 16S rRNA gene clones. A total of 1114 clones were classified while the remaining 25 clones were unclassified. A total of 103 bacterial species belonging to 42 genera were identified in POMC fluid samples by 16S rRNA gene analysis. Species of Prevotella (91%), Neisseria (73%), Fusobacterium (73%), Porphyromonas (73%), and Propionibacterium (73%) were found to be highly prevalent in all patients. Streptococcus mitis (64%), Fusobacterium nucleatum (55%), Propionibacterium acnes (55%), Staphylococcus capitis (55%), and Streptococcus salivarius (55%) were detected in more than 6 of the 11 patients. The results obtained by the culture method were different from those obtained by 16S rRNA gene analysis, but both approaches may be necessary for the identification of pathogens, especially of bacteria that are difficult to detect by culture methods, and the development of rational treatments for patients with POMC.

Effect of clarithromycin on acute asthma exacerbations in children: an open randomized study

BACKGROUND

Asthma exacerbations are major contributors to asthma morbidity and rather difficult to treat. There is inconclusive evidence that macrolide antibiotics may have an effect on asthma exacerbations through their antibacterial and/or anti-inflammatory properties. The aim of the study was to evaluate the efficacy of clarithromycin on medium-term asthma activity when given as an add-on therapy in children with acute asthma.

METHODS

This pilot, open-labeled, randomized, prospective study included 40 school-aged children, with intermittent or mild persistent asthma, presenting with an acute exacerbation. Children were randomized to receive 15 mg/kg of clarithromycin for 3 wk, in addition to their regular (GINA-guided) exacerbation treatment. The microbial trigger of exacerbations was assessed by serology and PCR. Children were followed up with diary cards for 12 wk; lung function was assessed at entry, 3, and 12 wk after the exacerbation.

RESULTS

Children in the clarithromycin group had significantly more symptom-free days (78 ± 2 vs. 69 ± 6 days, p < 0.00001) and less total number of periods with loss of control (9 vs. 19, respectively, p = 0.013) during the follow-up period, compared to controls. Moreover, treated children presented reduced duration of the index episode (5.0 ± 1 vs. 7.5 ± 1 days, p < 0.00001). Lung function did not differ between groups.

CONCLUSIONS

When added to regular treatment, a 3-wk course of clarithromycin was associated with an increase in the number of symptom-free days, reductions in the number and severity of days with loss of control following index episode, and a decrease in the duration of the initial asthma exacerbation.

Effect of erythromycin on cigarette-induced histone deacetylase protein expression and nuclear factor-κB activity in human macrophages in vitro

Histone deacetylases (HDACs) are families of enzymes that regulate chromatin structure and thus affect inflammatory gene expression. The anti-inflammatory properties of macrolides are well documented. However, the effects of macrolides on HDAC protein expression have not been studied. This study aimed to examine the molecular mechanism of the inflammatory responses caused by cigarette smoke extract (CSE) and the effects of erythromycin (EM) on CSE-induced HDAC protein expression in human macrophages in vitro. The cells were preincubated with EM and were then exposed to CSE. Levels of interleukin-8 (IL-8) and tumor necrosis factor-a (TNF-a) were assayed by enzyme linked immunosorbent assay (ELISA). Nuclear factor-κB (NF-κB) activity was assessed by an electrophoretic mobility shift assay. HDAC activity was measured with a colorimetric assay kit, and Western blotting was used for HDAC1, -2, -3 and NF-κB protein expression assays. The results showed that CSE causes decreases in HDAC activity and HDAC1, -2, -3 levels and upregulates NF-κB activity, resulting in increased NF-κB-dependent proinflammatory cytokine release in human macrophage cells. Moreover, EM was able to reverse the CSE-induced decline in HDAC1, -2, -3 protein expression, which was most prominent for HDAC2; these changes were associated with the suppression of both NF-κB protein expression and the production of inflammatory mediators. These results suggest that relieving inflammation with EM can be useful in therapeutic approaches for modulating intracellular nuclear signaling in chronic airway inflammatory diseases such as chronic obstructive pulmonary disease (COPD).

Azithromycin in acute bacterial upper respiratory tract infections: an Indian non-interventional study

To assess the effectiveness, safety and tolerability of azithromycin in acute bacterial upper respiratory tract infections (URTIs). In this open-label, prospective, multi-center, non-interventional study in bacterial URTI, the decision to prescribe azithromycin was independent of enrolment. Follow up was 1 week after treatment and if possible, at Week 2. Investigators' assessment of clinical outcome (Success/Failure) at the end of study was the primary endpoint for efficacy analysis. Clinical outcome of 'Success' was defined as the global response of Cure or Improvement. A pharmacoeconomic analysis of management of URTIs was also attempted. Of the 410 patients recruited, all were evaluated for safety and 278 for efficacy. The median treatment duration was 3 days. Following treatment with azithromycin, overall success rate was 98.92% (95% CI 96.88-99.78%; Clopper-Pearson method). The success rate was similar across the sub-groups of acute otitis media-100%, bacterial sinusitis-95.83%, and pharyngotonsillitis-99.38%. The success rate was 100% among children and adolescents (age ≤18 years) and 98.6% among adults (age >18 years). Most of the common signs and symptoms of URTI reported during baseline, significantly improved at the end of the study. Sixteen (3.90%) patients reported treatment emergent adverse events, the most common being diarrhea-5 (1.2%) and flatulence-2 (0.5%). The average cost of treating bacterial URTI was INR 716 per patient. Azithromycin is effective and well tolerated in Indian patients with bacterial URTIs.

Macrolides: from in vitro anti-inflammatory and immunomodulatory properties to clinical practice in respiratory diseases

BACKGROUND

Macrolides have long been recognised to exert immunomodulary and anti-inflammatory actions. They are able to suppress the "cytokine storm" of inflammation and to confer an additional clinical benefit through their immunomodulatory properties.

METHODS

A search of electronic journal articles was performed using combinations of the following keywords: macrolides, COPD, asthma, bronchitis, bronchiolitis obliterans, cystic fibrosis, immunomodulation, anti-inflammatory effect, diabetes, side effects and systemic diseases.

RESULTS

Macrolide effects are time- and dose-dependent, and the mechanisms underlying these effects remain incompletely understood. Both in vitro and in vivo studies have provided ample evidence of their immunomodulary and anti-inflammatory actions. Importantly, this class of antibiotics is efficacious with respect to controlling exacerbations of underlying respiratory problems, such as cystic fibrosis, asthma, bronchiectasis, panbrochiolitis and cryptogenic organising pneumonia. Macrolides have also been reported to reduce airway hyper-responsiveness and improve pulmonary function.

CONCLUSION

This review provides an overview on the properties of macrolides (erythromycin, clarithromycin, roxithromycin, azithromycin), their efficacy in various respiratory diseases and their adverse effects.

Actual concepts in rhinosinusitis: a review of clinical presentations, inflammatory pathways, cytokine profiles, remodeling, and management

Rhinosinusitis (RS) is a heterogeneous group of diseases. It is a significant and increasing health problem that affects about 15% of the population in Western countries. It has a substantial impact on patients’ health-related quality of life and daily functioning and represents a huge financial burden to society and the health care system as a result of the direct and indirect costs. In addition, RS is not well-understood, and little is known about the etiology and pathophysiology. In the past decade, many papers have been published that have changed our understanding of RS. RS is commonly classified into acute and chronic RS based on symptom duration. In acute RS, an inflammatory reaction initiated by a viral infection characterizes most uncomplicated, mild to moderate cases. Therefore, the first line of treatment for these cases are intranasal steroids and not antibiotics. In severe and complicated cases, antibiotics combined with topical steroids remain the treatment of choice. On the other hand, chronic RS is actually subdivided into two distinct entities (chronic rhinosinusitis with and without polyps), as growing evidence indicates that these entities have specific inflammatory pathways and cytokine profiles. The authors review recent data regarding the clinical presentations, cytokine profiles, tissue remodeling, and modalities of treatment for each form of RS.

Azithromycin inhibits IL-5 production of T helper type 2 cells from asthmatic children

BACKGROUND

Childhood asthma is a type 2 helper T (Th2) cell-driven inflammatory airway disease characterized by recurrent episodes of airway obstruction. Azithromycin (AZM), a macrolide antibiotic exhibiting anti-inflammatory activity aside from its antibacterial effect, may prove beneficial for asthmatic children. This study aimed to determine the effect of AZM on Th2 cells from atopic asthmatic children and non-atopic controls.

METHODS

CD4+ cells were isolated from peripheral blood mononuclear cells of 9 patients with asthma and 9 non-atopic individuals. Cells were activated as Th0 and differentiated into Th2 cells. The effect of AZM on activated CD4+ cells was evaluated with respective cell proliferation and cytokine production.

RESULTS

Th0 and Th2 CD4+ T cells from atopic asthmatic children produced greater interleukin (IL)-5 (Th2 cytokine) but lower interferon (IFN)-γ (Th1 cytokine) compared to the non-atopic controls, respectively. AZM inhibited IL-5 production of Th0 and Th2 cells from atopic asthmatics in a dose-dependent fashion, without significantly affecting their IL-13 and IFN-γ production. A similar effect was observed in non-atopic controls except that AZM did inhibit IFN-γ production of their Th0 cells. AZM at a higher dose decreased cell viability by inhibiting CD4+ T cell proliferation and enhanced their apoptosis, an effect similarly observed in Th0 and Th2 cells, and did not differ between asthmatic children and controls.

CONCLUSION

Our finding that AZM preferentially downregulates IL-5 production suggests its therapeutic potentials in controlling childhood asthma.

Clarithromycin for prevention of bronchiolitis obliterans syndrome in lung allograft recipients

BACKGROUND

Bronchiolitis obliterans syndrome (BOS) is the major limitation to long-term survival following lung transplantation and strategies to reduce its incidence have remained elusive. Macrolides may stabilize lung function in patients with established BOS. Their role, however, in prevention of BOS remains unexamined.

METHODS

Survival and BOS-free survival of 102 lung allograft recipients (LARs), transplanted at a single center between July 1995 and December 2001 who routinely received clarithromycin, were compared with two different control groups. The first control group consisted of 44 LARs from the same center who were transplanted from January 2002 onwards and did not receive clarithromycin. The second control group consisted of a contemporaneous cohort of 5089 recipients, transplanted between 1995 and 2001, reported to the United Network for Organ Sharing database.

RESULTS

When compared with the first control group, BOS-free survival was reduced in LARs receiving clarithromycin. Univariate (hazard ratio [HR] 3.13, p-value = 0.004) and multivariate (HR 3.49, p-value = 0.04) analyses showed that routine use of clarithromycin was associated with an increased risk of developing BOS. When compared with the second control group, the five-yr survival of clarithromycin group was similar (p-value = 0.24).

CONCLUSIONS

Routine use of clarithromycin does not delay development of BOS or improve survival.

Macrolide antibiotics broadly and distinctively inhibit cytokine and chemokine production by COPD sputum cells in vitro

Macrolide antibiotics are known to exert anti-inflammatory actions in vivo, including certain effects in COPD patients. In order to investigate the immunomodulatory profile of activity of macrolide antibiotics, we have studied the effects of azithromycin, clarithromycin, erythromycin and roxithromycin on the in vitro production of a panel of inflammatory mediators from cells isolated from human, steroid-naïve, COPD sputum samples. Macrolide effects were compared to three other commonly used anti-inflammatory compounds, the corticosteroid dexamethasone, the PDE4 inhibitor, roflumilast and the p38 kinase inhibitor, SB203580. Three of the four tested macrolides, azithromycin, clarithromycin and roxithromycin, exhibited pronounced, concentration-related reduction of IL-1β, IL-6, IL-10, TNF-α, CCL3, CCL5, CCL20, CCL22, CXCL1, CXCL5, and G-CSF release. Further slight inhibitory effects on IL-1α, CXCL8, GM-CSF, and PAI-1 production were also observed. Erythromycin was very weakly active. Qualitatively and quantitatively, macrolides exerted distinctive and, compared to other tested classes of compounds, more pronounced immunomodulatory effects, particularly in terms of chemokine (CCL3, CCL5, CCL20, CCL22, and CXCL5), IL-1β, G-CSF and PAI-1 release. The described modulation of inflammatory mediators could potentially contribute to further definition of biomarkers of macrolide anti-inflammatory activity in COPD.

Macrolide immunomodulation of chronic respiratory diseases

Important immunomodulatory properties of 14- and 15-membered macrolides may benefit patients with respiratory diseases associated with chronic inflammation. These properties include decreased neutrophil chemotaxis and infiltration into the respiratory epithelium, inhibition of transcription factors leading to decreased proinflammatory cytokine production, downregulation of adhesion molecule expression, inhibition of microbial virulence factors including biofilm formation, reduced generation of oxygen-free radicals, enhanced neutrophil apoptosis, and decreased mucus hypersecretion with improved mucociliary clearance. Chronic, low-dose macrolides have dramatically improved survival in patients with diffuse panbronchiolitis (DPB). Given the overlap in pathogenesis between DPB and other chronic respiratory diseases, macrolides are being investigated for cystic fibrosis, asthma, chronic bronchitis, chronic sinusitis, and chronic obstructive pulmonary disease. Preliminary data (largely from open-label trials) are promising, but conclusive results are needed.

Macrolide antibiotics in the treatment of asthma. An update

It seems clear that certain macrolide antibiotics exert anti-inflammatory and immune modulating effects beyond their purely antibacterial action, as has been demonstrated in a number of bronchial inflammatory disorders such as diffuse panbronchiolitis. Randomised, controlled clinical trials involving larger patient samples are needed to confirm whether these actions are of clinical relevance in application to asthma. On the other hand, the macrolide antibiotics have a long half-life, with a prolonged elimination interval, which appears to favour the development of resistances that persist over the long term, as in the case of azithromycin. Would the risk/benefit ratio of sustained low-dose macrolide use be justified, considering the risk of selecting resistant strains? A number of questions must be answered before these drugs can be recommended in application to asthmatic patients: In which patients should they be used? Which drug or drugs would be most appropriate? What would the recommended dose be, and for how long should treatment be administered? What adverse effects can be expected?