Effect of 14-membered ring macrolide therapy on chronic respiratory tract infections and polymorphonuclear leukocyte activity

Primary Ciliary Dyskinesia with Refractory Chronic Rhinosinusitis

Patient: Male, 49-year-old

Final Diagnosis: Situs inversus

Symptoms: Cough • nasal congestion • nasal obstruction

Medication:—

Clinical Procedure: —

Specialty: Otolaryngology

Anti-Inflammatory Effects of EM900 on Cultured Human Nasal Epithelial Cells

OBJECTIVES

Macrolide therapy is an important conservative therapy for chronic rhinosinusitis, especially in Japan. The mechanism underlying this therapy involves anti-inflammatory and not antimicrobial activity. However, the administration of long-term low-dose macrolides (LTLMs) causes an increase in the number of antibiotic-resistant bacteria. EM900 is a derivative of erythromycin (EM), with anti-inflammatory but not antibacterial effects. It does not induce macrolide-resistant bacteria as shown by LTLM. In the present study, we analyzed the inhibitory effects of EM900 in comparison with those of clarithromycin (CAM) on inflammatory cytokine production in human nasal epithelial cells (HNEpCs).

METHODS

After HNEpCs were cultured for 4 days, CAM or EM900 was added into the culture, followed by stimulation with tumor necrosis factor (TNF)-α. Interleukin (IL)-8 and vascular endothelial growth factor (VEGF) levels were measured using real-time polymerase chain reaction (RT-PCR) and an enzyme-linked immunosorbent assay (ELISA).

RESULTS

Both the ELISA and RT-PCR showed that EM900 and CAM significantly inhibited IL-8 production in HNEpCs. In contrast, EM900 and CAM did not suppress the increased VEGF production when HNEpCs were stimulated with TNF-α.

CONCLUSION

EM900 showed an anti-inflammatory effect, such as that of CAM, due to the inhibitory effect on IL-8 production in HNEpCs.

Past, present and future of macrolide therapy for chronic rhinosinusitis in Japan

In 1984, the effectiveness of low-dose, long-term erythromycin treatment (macrolide therapy) for diffuse panbronchiolitis (DPB) was first reported in Japan. The 5-year survival rate for DPB improved from 62.9 to 91.4% after implementation of macrolide therapy. The usefulness of this treatment has since been demonstrated in patients with other chronic airway diseases, such as chronic bronchitis, cystic fibrosis, bronchiectasis, bronchial asthma, and chronic rhinosinusitis (CRS). The new 14-membered macrolides clarithromycin and roxithromycin and the 15-membered macrolide azithromycin are also effective for treating these inflammatory diseases. The mechanism of action of the 14- and 15-membered macrolides may involve anti-inflammatory rather than anti-bacterial activities. Macrolide therapy is now widely used for the treatment of CRS in Japan; it is particularly effective for treating neutrophil-associated CRS and is useful for suppressing mucus hypersecretion. However, macrolide therapy is not effective for eosinophil-predominant CRS, which is characterized by serum and tissue eosinophilia, high serum IgE levels, multiple polyposis, and bronchial asthma. Recent reports have described the clinical efficacy of macrolides in treating other inflammatory diseases and new biological activities (e.g., anti-viral). New macrolide derivatives exhibiting anti-inflammatory but not anti-bacterial activity thus have therapeutic potential as immunomodulatory drugs. The history, current state, and future perspectives of macrolide therapy for treating CRS in Japan will be discussed in this review.

Prolonged antibiotics for non-cystic fibrosis bronchiectasis in children and adults

BACKGROUND

The vicious cycle hypothesis for bronchiectasis predicts that bacterial colonisation of the respiratory tract perpetuates inflammatory change. This damages the mucociliary escalator, preventing bacterial clearance and allowing persistence of pro-inflammatory mediators. Conventional treatment with physiotherapy and intermittent antibiotics is believed to improve the condition of people with bronchiectasis, although no conclusive data show that these interventions influence the natural history of the condition. Various strategies have been tried to interrupt this cycle of infection and inflammation, including prolonging antibiotic treatment with the goal of allowing the airway mucosa to heal.

OBJECTIVES

To determine the benefits of prolonged antibiotic therapy in the treatment of patients with bronchiectasis.

SEARCH METHODS

We searched the Cochrane Airways Group Trials Register and reference lists of identified articles. Searches were current as of February 2014.

SELECTION CRITERIA

Randomised trials examining the use of prolonged antibiotic therapy (for four or more weeks) in the treatment of bronchiectasis compared with placebo or usual care.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and extracted data. We contacted study authors to ask for missing information.

MAIN RESULTS

Eighteen trials met the inclusion criteria, randomly assigning a total of 1157 participants. Antibiotics were given for between four weeks and 83 weeks. Limited meta-analysis was possible because of the diversity of outcomes reported in these trials. Based on the number of participants with at least one exacerbation, the meta-analysis showed significant effects in favour of the intervention (odds ratio (OR) 0.31, 95% confidence interval (CI) 0.19 to 0.52; P value < 0.00001), with events occurring in 271 per 1000 people in the intervention arm (95% CI 126 to 385) and in 546 per 1000 in the control population, based on evidence of moderate quality. A non-statistically significant reduction in hospitalisation favoured the use of prolonged antibiotics with a moderate quality grade of supporting evidence (37 per 1000 in the intervention arm (95% CI 13 to 96) and 87 per 1000 in control (OR 0.40, 95% CI 0.14 to 1.11; P value = 0.08). Drug resistance developed in 36 of 220 participants taking antibiotics compared with 10 of 211 participants given placebo or standard therapy (OR 3.48, 95% CI 1.20 to 10.07; P value = 0.02), translating to natural frequencies of 155 per 1000 in the intervention arm (95% CI 59 to 346) and 50 per 1000 in the control arm. The intervention was well tolerated with no overall significant difference in withdrawal between treatment and placebo groups (OR 0.91, 95% CI 0.56 to 1.49). Diarrhoea was commonly reported as an adverse event, particularly with an oral intervention.

AUTHORS' CONCLUSIONS

Available evidence shows benefit associated with use of prolonged antibiotics in the treatment of patients with bronchiectasis, at least halving the odds of exacerbation (with 275 fewer exacerbations per every 1000 people treated in the antibiotic arm compared with the control arm) and hospitalisation (50 fewer hospitalisations per 1000 people in the antibiotic arm compared with the control arm). However, the risk of emerging drug resistance is increased more than threefold. This review is limited by diversity of trials and by evidence of moderate to low quality. Further randomised controlled trials with adequate power and standardised end points are required.

Itraconazole and clarithromycin inhibit P-glycoprotein activity in primary human sinonasal epithelial cells

BACKGROUND

Itraconazole and clarithromycin are clinically effective in the treatment of chronic rhinosinusitis (CRS) through incompletely understood anti-inflammatory properties. P-glycoprotein (P-gp) is overexpressed in CRS and inhibition results in decreased inflammatory cytokine secretion. Both itraconazole and clarithromycin have also been shown to have P-gp inhibitory properties in other tissues, suggesting a novel explanation for their immunomodulatory effects in CRS. The purpose of this study is to therefore confirm whether these drugs are capable of inhibiting P-gp specifically in sinonasal epithelial cells.

METHODS

This was an institutional review board (IRB)-approved study in which primary sinonasal epithelial cells were cultured in 96-well plates. A Calcein AM assay was used to quantify P-gp inhibition as determined by an increase in intracellular fluorescence. A dose-response curve was generated for itraconazole and clarithromycin (maximal concentration 100 μM) and compared to that of Zosuquidar, a highly specific known P-gp inhibitor. Results were compared using a Student t test with a significance defined as p < 0.05.

RESULTS

Both itraconazole and clarithromycin demonstrated a dose-response curve for P-gp inhibition similar to that of Zosuquidar. The respective maximal inhibitory concentrations of Zosuquidar, itraconazole, and clarithromycin prior to induction of cytotoxicity were 0.31, 3.13, and 1.56 μM, respectively, as demonstrated by a statistically significant increase in total intracellular fluorescence (p < 0.05 in all groups).

CONCLUSION

Both itraconazole and clarithromycin are capable of inhibiting sinonasal epithelial cell associated P-gp. The anti-inflammatory effects of these agents in CRS may be attributable, in part, to their heretofore unrecognized P-gp modulatory properties.

Anti-inflammatory effects of a novel non-antibiotic macrolide, EM900, on mucus secretion of airway epithelium

OBJECTIVE

Low-dose, long-term use of 14-membered macrolides is effective for treatment of patients with chronic airway inflammation such as diffuse panbronchiolitis or chronic rhinosinusitis. However, long-term use of macrolides can promote the growth of drug-resistant bacteria, and the development of anti-inflammatory macrolides that lack antibiotic effects is desirable. Previously, we developed EM900, a novel 12-membered erythromycin A derivative, which has potent anti-inflammatory and immunomodulatory activities and lacks any antibacterial activity. We examined the anti-inflammatory effects of EM900 on mucus secretion from airway epithelial cells.

METHODS

To examine the in vivo effects of EM900 on airway inflammation, we induced hypertrophic and metaplastic changes of goblet cells in rat nasal epithelium via intranasal instillation of lipopolysaccharides. In vitro effects of EM900 on airway epithelial cells were examined using cultured human airway epithelial (NCI-H292) cells. Mucus secretion was evaluated via enzyme-linked immunosorbent assays with an anti-MUC5AC monoclonal antibody.

RESULTS

Oral administration of EM900 or clarithromycin (CAM) significantly inhibited LPS-induced mucus production from rat nasal epithelium. EM900, CAM, or erythromycin significantly inhibited MUC5AC secretion induced by tumor necrosis factor-α from NCI-H292 cells. MUC5AC mRNA expression was also significantly lower in EM900-treated cells.

CONCLUSION

These results indicated that a novel non-antibiotic macrolide, EM900 exerted direct inhibitory effects on mucus secretion from airway epithelial cells, and that it may have the potential to become a new anti-inflammatory drug for the treatment of chronic rhinosinusitis.

The effects of azithromycin on patients with diffuse panbronchiolitis: a retrospective study of 29 cases

BACKGROUND

Diffuse panbronchiolitis (DPB), a chronic inflammatory disease of the airway, is treated with macrolide antibiotics. The ability of azithromycin to improve DPB prognosis, as detected by high-resolution computed tomography (HRCT) scans and lung function tests, has not been studied in a large retrospective of patients. Our study aims to investigate the effects of azithromycin on patients with DPB using lung function tests and radiologic images.

METHODS

Twenty-nine patients with DPB were studied; their medical records were collected and analyzed retrospectively. Patients studied were hospitalized in the respiratory department of the Yixing Hospital, affiliated with Jiangsu University. Azithromycin was administered for 6-17 months. Changes in lung function and HRCT scans after treatment with azithromycin for six months were compared with pre-treatment values and images respectively.

RESULTS

Azithromycin therapy for six months resulted in rapid improvements in lung function, demonstrated by forced expiratory volume in one second (FEV1.0%), forced expiratory volume in one second over the forced vital capacity (FEV1.0/FVC), and forced expiratory volume with 75% vital capacity (FEF75%) values. In addition, improvements were seen in small nodular shadows, dilated peripheral bronchi, bronchial wall thickening, and tree-in-bud pattern, as detected by chest HRCT scans.

CONCLUSIONS

Long-term therapy with azithromycin is effective for patients with DPB.

WBC count and functional changes induced by co-administration of clofazimine and clarithromycin, in single and multiple doses, in Wistar rats

Clofazimine and clarithromycin are used to treat leprosy and infections caused by Mycobacterium avium complex. Little data on the toxicity of co-administration of these two drugs are available. Here we evaluated the potential adverse effects of polytherapy with these two drugs in male Wistar rats by determining WBCs counts and other blood cell counts, neutrophilic phagocytosis, and burst oxidative, by flow cytometry. We observed an increase in WBCs, in multiple-dose regimens, and in polymorphonuclear cells, in both single- clarithromycin only and multiple dose regimens. We also observed a reduction in mononuclear cell counts in single and multiple doses. The drugs seem to reverse the mononuclear and polymorphonuclear cell ratio. An increase in oxidative burst was observed in animals treated with the drugs administered either individually or combined. In conclusion, clofazimine and clarithromycin change WBCs counts. Our results may contribute for a better understanding of the mechanisms related to the effects of co-administrating the two drugs.

Diffuse Panbronchiolitis

Diffuse panbronchiolitis (DPB) is characterized by chronic sinobronchial infection and diffuse bilateral micronodular pulmonary lesions consisting of inflammatory cells. Studies on disease etiology point to a genetic predisposition unique to Asians. Early therapy for DPB was largely symptomatic. The advent of macrolide antibiotics, including erythromycin, roxithromycin and clarithromycin, has strikingly changed disease prognosis. Low-dose, long-term macrolide therapy for DPB originated from detailed observations of response to therapy in a single patient. The bactericidal activity of macrolides, particularly erythromycin, is not a significant factor for their clinical efficacy in DPB. Firstly, irrespective of bacterial clearance, clinical improvement is observed in patients treated with erythromycin. Secondly, even in cases with bacterial superinfection with Pseudomonas aeruginosa resistant to macrolides, treatment has proved effective. Thirdly, the recommended dosage of macrolides produces peak levels in tissue that are below the minimum inhibitory concentrations for major pathogenic bacteria that colonize the airway. In the last two decades, the possible mechanism underlying the effectiveness of macrolide therapy has been extensively studied. The proposed mechanism of action includes inhibition of excessive mucus and water secretion from the airway epithelium, inhibition of neutrophil accumulation in the large airway, inhibition of lymphocyte and macrophage accumulation around the small airway, and modulation of bacterial virulence. The great success of macrolide therapy in diffuse panbronchiolitis may extend its application to the treatment of other chronic inflammatory disorders. If the anti-inflammatory activity of macrolides is independent of their bactericidal effect, new anti-inflammatory macrolides without antimicrobial activity should be developed to minimize emergence of macrolide-resistant micro-organisms.

Influence of macrolide maintenance therapy and bacterial colonisation on exacerbation frequency and progression of COPD (COLUMBUS): study protocol for a randomised controlled trial

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is characterised by progressive development of airflow limitation that is poorly reversible. Because of a poor understanding of COPD pathogenesis, treatment is mostly symptomatic and new therapeutic strategies are limited. There is a direct relationship between the severity of the disease and the intensity of the inflammatory response. Besides smoking, one of the hypotheses for the persistent airway inflammation is the presence of recurrent infections. Macrolide antibiotics have bacteriostatic as well as anti-inflammatory properties in patients with cystic fibrosis and other inflammatory pulmonary diseases. There is consistent evidence that macrolide therapy reduces infectious exacerbations, decreases the requirement for additional antibiotics and improves nutritional measures. Because of these positive effects we hypothesised that maintenance macrolide therapy may also have beneficial effects in patients with COPD who have recurrent exacerbations. The effects on development of bacterial resistance to macrolides due to this long-term treatment are unknown. Until now, studies investigating macrolide therapy in COPD are limited. The objective of this study is to assess whether maintenance treatment with macrolide antibiotics in COPD patients with three or more exacerbations in the previous year decreases the exacerbation rate in the year of treatment and to establish microbial resistance due to the long-term treatment.

METHODS/DESIGN

The study is set up as a prospective randomised double-blind placebo-controlled single-centre trial. A total of 92 patients with COPD who have had at least three exacerbations of COPD in the previous year will be included. Subjects will be randomised to receive either azithromycin 500 mg three times a week or placebo. Our primary endpoint is the reduction in the number of exacerbations of COPD in the year of treatment.

DISCUSSION

We investigate whether long-term therapy with macrolide antibiotics can prevent exacerbations in patients with COPD. Additionally, our study aims to assess the effect of long-term use of macrolide on the development of antimicrobial resistance and on inflammatory parameters related to COPD. We believe this study will provide more data on the effects of macrolide treatment in patients in COPD and will add more knowledge on its working mechanisms.

TRIAL REGISTRATION

http://www.clinicaltrials.gov NCT00985244.

Azithromycin inhibits mucus hypersecretion from airway epithelial cells

To examine the in vivo effects of the 15-member macrolide, azithromycin (AZM), on mucus hypersecretion, we induced hypertrophic and metaplastic changes of goblet cells in rat nasal epithelium by intranasal instillation of ovalbumin (OVA) in OVA-sensitized rats, or by intranasal lipopolysaccharides (LPS) instillation. Oral administration of AZM (5–10 mg/kg) or clarithromycin (CAM, 5–10 mg/kg) significantly inhibited OVA- and LPS-induced mucus production, whereas josamycin (JM) or ampicillin (ABPC) showed no effect. In vitro effects of AZM on airway epithelial cells were examined using NCI-H292 cells and human nasal epithelial cells cultured in air-liquid interface. Mucus secretion was evaluated by enzyme-linked immunosorbent assay using an anti-MUC5AC monoclonal antibody. AZM or CAM significantly inhibited tumor necrosis factor-α (TNF-α) (20 ng/mL)-induced MUC5AC secretion from NCI-H292 cells at 10⁻⁶–10⁻⁷ M, whereas JM or ABPC showed no effect. AZM significantly inhibited TNF-α (20 ng/mL)-induced MUC5AC secretion from human nasal epithelial cells at 10⁻⁴ M. MUC5AC mRNA expression was also significantly inhibited. These results indicate that the 15-member macrolide, AZM, exerts direct inhibitory effects on mucus secretion from airway epithelial cells and that it may be useful for the treatment of mucus hypersecretion caused by allergic inflammation and LPS stimulation.

The role of macrolides in noncystic fibrosis bronchiectasis

Objective. The present study aims at reviewing the main publications on the use of macrolides as immunomodulators in patients with noncystic fibrosis bronchiectasis. Source of Data. The Medline database was our source of data for this research carried out until June 2011, using the key words: macrolides and bronchiectasis, while searching for original articles and reviews. Summary of Data. Seven clinical studies that evaluated the action of the macrolides in patients with bronchiectasis were found. There was the sputum volume, reduction in pulmonary exacerbation frequency, and in the use of antimicrobial treatment, in addition to pulmonary function improvement. Conclusions. Anti-inflammatory action and immunomodulatory effects can be attributed to macrolides when administered in low doses and on the long term. This use has been well established both in diffuse panbronchiolitis and in cystic fibrosis. Evidence indicates possible benefits in bronchiectasis. Future studies are needed, though, to establish the ideal dose and treatment duration and to understand the implications in the generation of microbial resistance."When patients have bacteria that are resistant to all antibiotics, prescribe erythromycin, leave them on it for a long time, and they will do much better"Dr. Harry Shwachman, 1950.

Mechanisms of action and clinical application of macrolides as immunomodulatory medications

Macrolides have diverse biological activities and an ability to modulate inflammation and immunity in eukaryotes without affecting homeostatic immunity. These properties have led to their long-term use in treating neutrophil-dominated inflammation in diffuse panbronchiolitis, bronchiectasis, rhinosinusitis, and cystic fibrosis. These immunomodulatory activities appear to be polymodal, but evidence suggests that many of these effects are due to inhibition of extracellular signal-regulated kinase 1/2 (ERK1/2) phosphorylation and nuclear factor kappa B (NF-kappaB) activation. Macrolides accumulate within cells, suggesting that they may associate with receptors or carriers responsible for the regulation of cell cycle and immunity. A concern is that long-term use of macrolides increases the emergence of antimicrobial resistance. Nonantimicrobial macrolides are now in development as potential immunomodulatory therapies.

Effects of azithromycin on glutathione S-transferases in cystic fibrosis airway cells

Anti-inflammatory properties of azithromycin (AZM) have been proposed as possible mechanisms of clinical beneficial effects in patients with cystic fibrosis (CF). Altered glutathione (GSH) transport in cystic fibrosis transmembrane regulator protein (CFTR)-deficient cells leads to the occurrence of oxidative stress that finally induces glutathione S-transferase (GST) activity. The present investigation was aimed to verify the effects of AZM on GST activity and expression in CF airway cells in vitro and in vivo. AZM exposure significantly decreased GSTT1 and GSTM1 mRNA and protein expression in IB3-1, restoring the levels to those observed in non-CF C38 cells, which also express lower levels of gamma-glutamyltransferase (GGT) activity than IB3-1. In another CF cell line, 2CFSMEo-, AZM produced 45% reduction in GSTT1 and GSTM1 mRNA levels. AZM reduced GST activity by approximately 25% and 40% in IB3-1 and 2CFSMEo- cells, respectively. GSTP1 was similarly expressed in all CF and non-CF cells and was unaffected by AZM. The anti-inflammatory cytokine IL-10 down-modulated GST activity at similar levels, supporting a link between GST inhibition and anti-inflammatory properties of AZM. In bronchoalveolar lavage fluid of CF mice homozygous for the F508 del mutation, GSTM1 protein levels were undetectable after AZM treatment. The association between increased GST expression and activity, together with its reversal by AZM treatment in vitro and in vivo, suggest novel antioxidant properties for this drug. The issue whether decreased GST activity may directly concur to anti-inflammatory properties of AZM or is rather a marker of the oxidative status of CF cells will require additional studies.

Characteristic cell wall ultrastructure of a macrolide-resistant Staphylococcus capitis strain isolated from a patient with chronic sinusitis

Fourteen-membered-ring macrolides have an antiinflammatory effect, in addition to their antibacterial effect, and are widely used at low dosages for long-term therapy for chronic inflammatory disease such as diffuse pan-bronchiolitis and chronic sinusitis. A macrolide-resistant coagulase-negative staphylococcal strain was obtained from the maxillary sinus of a patient with chronic sinusitis, who failed long-term macrolide therapy. The isolated strain was characterized as Staphylococcus capitis and had an MIC for erythromycin greater than 128 microg/ml. Morphological observation demonstrated that this macrolide-resistant S. capitis strain had a thicker cell wall than macrolide-sensitive S. capitis strains. Moreover, the strain was not carrying any other than the four genes that are known mainly to encode for macrolide resistance in S. aureus. Therefore, the strain had an unknown macrolide-resistance mechanism that might be related to cell wall thickening.

Mycoplasma pneumoniae and its role in asthma

Mycoplasma pneumoniae (M pneumoniae), primarily recognised as a causative agent of community-acquired pneumonia has recently been linked to asthma. An infection with M pneumoniae may precede the onset of asthma or exacerbate asthma symptoms. Chronic infection with M pneumoniae has been suspected to play a part in some patients with asthma. The role of immunoglobulin E-related hypersensitivity and induction of T helper type 2 immune response leading to inflammatory response in M pneumoniae-infected patients with asthma have also been proposed. Use of macrolides in reducing asthma symptoms only in M pneumoniae-infected patients supports the use of macrolides in patients with asthma having M pneumoniae infection. As macrolides are both antimicrobial and anti-inflammatory drugs, the therapeutic role of their biphasic nature in reducing asthma symptoms needs further attention in clinical research.

Recurrence of bilateral diffuse bronchiectasis after bilateral lung transplantation

We report two cases of bilateral diffuse bronchiectasis in which early recurrence of the original lung disease occurred after bilateral lung transplantation (LT). Patient 1 underwent cadaveric LT. Recurrent bronchiectasis occurred 4 months later, and he died 6 years after LT. Patient 2 underwent living-related lobar LT, bronchiectasis relapsed 4 months later, and he died 13 months after LT. Both cases were finally diagnosed as bilateral diffuse bronchiectasis by the pathological features of the explanted lungs: infiltration of inflammatory cells predominantly in the conducting airways with dilation of the bronchi of bilateral lungs and scarcity of foamy macrophages in the wall of the respiratory bronchioles. Similar pathological features were seen in autopsy specimens from patient 1 and a transbronchial biopsy specimen from patient 2. LT should be carried out with caution in patients with bilateral diffuse bronchiectasis. When performing LT in such patients, it is suggested that sinusitis should be controlled perioperatively.

Clinical implications of the immunomodulatory effects of macrolides on sinusitis

This article reviews the treatment of chronic sinusitis with macrolides. Chronic sinusitis is often the result of bacterial infections that lead to chronic inflammation with thickening of the sinus mucosa and hypersecretion of mucus. In addition to their anti-infective properties, some macrolides possess immunomodulatory effects. These macrolides have been used successfully to treat diffuse panbronchiolitis, a progressive inflammatory lung disease, and may be useful for treatment of asthma, chronic bronchitis, chronic sinusitis, cystic fibrosis, and bronchiectasis. The clinical benefits of macrolides in patients with chronic sinusitis include decreased nasal secretions and postnasal drip, with improvement in nasal obstruction. In vivo and in vitro studies show that some macrolides affect neutrophil chemotaxis and infiltration, inflammatory cytokine production, mucus production, and the transportability of airway secretions. These findings indicate that macrolides are promising agents for treating chronic inflammation of the airways.

Applying lessons learned in the treatment of diffuse panbronchiolitis to other chronic inflammatory diseases

In addition to having antibacterial effects, macrolides modulate inflammatory responses. Their effectiveness in treating chronic inflammatory airway disease is well documented in patients with diffuse panbronchiolitis (DPB), a chronic condition characterized by inflammation of the airways that, if left untreated, progressively leads to respiratory failure and death. Long-term treatment with certain macrolides has dramatically improved the survival of patients with DPB. The mechanisms of action for the anti-inflammatory properties of macrolides are still being studied. The effects of macrolides on inflammation include decreasing chemotaxis of neutrophils to the respiratory tract and inhibiting the expression of adhesion molecules, with decreased infiltration of neutrophils into the respiratory epithelium. Macrolides also inhibit expression of transcription factors and formation of proinflammatory cytokines, and directly and indirectly block mucus secretion. Even with long-term use, macrolides are safe and well tolerated. The effectiveness of macrolides for treating DPB has led to interest in their use in treating other chronic inflammatory airway diseases. As discussed in this article, because of the similarities between the clinical presentation of cystic fibrosis and chronic bronchitis and DPB, the effects of macrolides in patients with these diseases are currently being studied with particular interest.

The Effect of Clarithromycin on Inflammatory Markers in Chronic Obstructive Pulmonary Disease: Preliminary Data

BACKGROUND:

Clarithromycin is an antimicrobial agent that can be used for treatment of chronic obstructive pulmonary disease (COPD) exacerbations with bronchodilator therapy. However, it has also been shown that clarithromycin has antiinflammatory effects by the inhibition of cytokine production.

OBJECTIVE:

To evaluate the antiinflammatory effect of clarithromycin on serum and sputum interleukin-8 (IL-8), tumor necrosis factor-α (TNF-α), and leukotriene B4 levels in patients with COPD.

METHODS:

Thirty men with mild to moderate COPD were enrolled in this prospective, single-center, double-blind, placebo-controlled study. None of the patients was receiving systemic or inhaled corticosteroids during the study. Subjects received either clarithromycin or placebo for 14 days. Before and after this treatment period, spirometric tests and arterial blood gas analysis were performed, blood was drawn for measurement of serum inflammatory markers, and sputum was induced.

RESULTS:

There were no statistically significant differences in baseline clinical or laboratory parameters between the groups. After the treatment, the induced sputum total cell counts, and IL-8 and TNF-α levels decreased significantly in the clarithromycin group compared with pretreatment levels (mean ± SD IL-8 1606 ± 367.3 vs 882 ± 143.6 pg/mL, p = 0.001; TNF-α 638.2 ± 287.5 vs 390 ± 235 pg/mL, p = 0.001). Similarly, decreases in serum inflammatory markers were found in the clarithromycin group while there was no significant change in the placebo group.

CONCLUSIONS:

This study demonstrated that the decrease in IL-8 and TNF-α levels might be related to the antiinflammatory effect of clarithromycin. Thus, we suggest that the use of clarithromycin in COPD exacerbations may either treat the infection or help control the inflammation. Future studies are needed to determine the clinical significance of these findings.

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

In addition to their well-known antimicrobial activity, macrolides possess immunomodulatory properties that may confer beneficial effects to patients with respiratory diseases associated with chronic inflammation. These properties include attenuation of inflammatory responses in the lung, mucoregulatory properties, and effects on bronchial responsiveness. Macrolides increase mucociliary clearance, improve sinusitis symptoms, and decrease nasal secretions and polyp size in patients with sinusitis. They also have been shown to modify the inflammatory response associated with chronic sinusitis. In patients with asthma, macrolides have been reported to reduce airway hyperresponsiveness and improve pulmonary function, and have historically been selected for their "steroid-sparing" effect. Preliminary data from studies of patients with COPD have shown improvements in symptom scores and FEV(1) after macrolide treatment. As biological response modifiers, macrolides have the potential to improve the outcomes of patients with inflammatory airway diseases. Large scale, placebo-controlled clinical trials designed to assess long-term efficacy and safety in these diseases are warranted.

Tratamiento con azitromicina en la fibrosis quística

Progressive lung disease, caused by chronic endobronchial colonization, is the major cause of morbidity and mortality in patients with cystic fibrosis (CF). Several pathogens, including Staphylococcus aureus and Pseudomonas aeruginosa are responsible for this effect. The steadily improving prognosis of CF has been attributed to the use of antibiotics with activity against these organisms. Despite a significant increase in the amount of published material demonstrating the potential role of macrolide antibiotics as antiinflammatory agents and their effects on bacterial virulence, their mechanism of action in CF patients is still unknown. Although there is a limited number of clinical trials assessing the efficacy and safety of azithromycin (AZM) in CF, increasing evidence suggests that 3 to 6-month AZM treatment in CF patients is safe and well tolerated. This treatment results in clinical improvement, decreasing the number of pulmonary exacerbations and increasing pulmonary function. Therefore, chronic treatment with AZM should be considered in CF patients added to conventional therapy. Clinical experience with macrolides other than AZM in CF patients is very limited.

Macrolides inhibit epithelial cell-mediated neutrophil survival by modulating granulocyte macrophage colony-stimulating factor release

Macrolides have been shown to be effective in treating diffuse panbronchiolitis (DPB), although the precise modes of action remain unclear. At sites of airway inflammation, respiratory epithelium is considered an active participant in regulating neutrophil survival. We therefore examined the effect of erythromycin, clarithromycin, azithromycin, and josamycin on both neutrophil survival and on epithelial-derived factors, which influence neutrophil longevity. Media conditioned with transiently tumor necrosis factor (TNF)-alpha-stimulated A549 human airway epithelial cells prolonged neutrophil survival compared with control media. The presence of dexamethasone during neutrophil culture led to further prolongation of neutrophil survival. In contrast, none of the tested macrolides modulated neutrophil survival, suggesting a lack of direct effect of these drugs. On the other hand, pretreatment of TNF-alpha-stimulated A549 cells by erythromycin, clarithromycin, azithromycin, or dexamethasone, but not josamycin, decreased the neutrophil survival-enhancing effects in a dose-dependent manner. Neutralizing antibodies to granulocyte macrophage colony-stimulating factor (GM-CSF) dampened the prolonged neutrophil survival observed in TNF-alpha-stimulated A549 conditioned media. Erythromycin, clarithromycin, azithromycin, and dexamethasone inhibited TNF-alpha-induced GM-CSF expression in A549 cells at both the protein and messenger RNA levels. These results suggest that macrolides inhibit epithelial cell-mediated neutrophil survival by modulating GM-CSF release, which may, at least in part, explain the effectiveness of this family of drugs on DPB.

In vivo and in vitro effects of macrolide antibiotics on mucus secretion in airway epithelial cells

To examine the in vivo effects of macrolide antibiotics on mucus hypersecretion, we induced hypertrophic and metaplastic changes of goblet cells in rat nasal epithelium by intranasal instillation of ovalbumin (OVA) in OVA-sensitized rats and by intranasal LPS instillation. Oral administration of clarithromycin (CAM) (5-10 mg/kg) significantly inhibited OVA- and LPS-induced mucus production and neutrophil infiltration, whereas josamycin and ampicillin showed no effect. In vitro effects of macrolide antibiotics on airway epithelial cells were examined using NCI-H292 cells and human nasal epithelial cells cultured in air-liquid interface. Mucus secretion was evaluated by ELISA using anti-mucin monoclonal antibodies (anti-MUC5AC and HCS18). CAM and erythromycin significantly inhibited spontaneous and tumor necrosis factor-alpha (20 ng/ml)-induced mucus secretion from NCI-H292 cells at 10-6 to 10-7 M and from human nasal epithelial cells at 10-4 to 10-5 M. MUC5AC messenger RNA expression was also significantly inhibited. These results indicate that the 14-member macrolide antibiotics, CAM and erythromycin, exert direct inhibitory effects on mucus secretion from airway epithelial cells and that they may be useful for the treatment of mucus hypersecretion caused by allergic inflammation and LPS stimulation.

Maintenance azithromycin therapy for bronchiolitis obliterans syndrome: results of a pilot study

Bronchiolitis obliterans syndrome remains the leading cause of morbidity and mortality in the pulmonary transplant population. Previous studies show that macrolide antibiotics may be efficacious in the treatment of panbronchiolitis and cystic fibrosis. In the latter, azithromycin decreases the number of respiratory exacerbations, improves FEV1, and improves quality of life. We hypothesized that oral azithromycin therapy may improve lung function in patients with bronchiolitis obliterans syndrome. To test this hypothesis, we conducted an open-label pilot trial using maintenance azithromycin therapy in six lung transplant recipients (250 mg orally three times per week for a mean of 13.7 weeks). In this study, five of these six individuals demonstrated significant improvement in pulmonary function, as assessed by FEV1, as compared with their baseline values at the start of azithromycin therapy. The mean increase in the percentage of predicted FEV1 values in these individuals was 17.1% (p </= 0.05). In addition, the absolute FEV1 increased by 0.50 L (range -0.18 to 1.36 L). These data suggest a potential role for maintenance macrolide therapy in the treatment of bronchiolitis obliterans syndrome in lung transplant recipients.

Diffuse panbronchiolitis--pathophysiology and treatment mechanisms

Diffuse panbronchiolitis (DPB) is a chronic, potentially life-threatening lower respiratory tract disease that is particularly common in Japanese people. It is characterized by chronic infiltration of inflammatory cells, and Pseudomonas aeruginosa is isolated from sputum in some cases. Bronchoalveolar lavage fluid from DPB patients contains high concentrations of neutrophils, lymphocytes and inflammatory cytokines compared with levels found in other chronic lung diseases. If left untreated, DPB progresses rapidly and is usually fatal, but long-term, low-dose macrolide therapy improves the prognosis. Macrolides are effective against DPB even in the absence of a P. aeruginosa infection. There is evidence that these antibiotic agents may have an anti-inflammatory mode of action in DPB.

Anti-inflammatory effects of macrolide antibiotics

Macrolides are widely used as antibacterial drugs. Clinical and experimental data, however, indicate that they also modulate inflammatory responses, both contributing to the treatment of infective diseases and opening new opportunities for the therapy of other inflammatory conditions. Considerable evidence, mainly from in vitro studies, suggests that leukocytes and neutrophils in particular, are important targets for modulatory effects of macrolides on host defense responses. This underlies the use of the 14-membered macrolide erythromycin for the therapy of diffuse panbronchiolitis. A variety of other inflammatory mediators and processes are also modulated by macrolides, suggesting that the therapeutic indications for these drugs may be extended significantly in future.

Gene expression profiles of human small airway epithelial cells treated with low doses of 14- and 16-membered macrolides

Although long-term treatment with low doses of 14-membered macrolides is widely applied in management of patients with chronic inflammatory diseases, e.g., diffuse panbronchiolitis, chronic bronchitis, or chronic lung damage in newborns, the physiological mechanisms underlying the action of macrolides in these conditions are unclear. To clarify the pathological basis of these diseases and also to aid in the design of novel drugs to treat them, we chose to investigate the molecular target(s) of macrolides. Our experiments involved long-term culture of human small airway epithelial cells (hSAEC) in media containing 14-membered macrolides erythromycin (EM) or clarithromycin (CAM), or a 16-membered macrolide, josamycin (JM), which lacks clinical anti-inflammatory effects. We then analyzed gene expression profiles in the treated cells using a cDNA microarray consisting of 18,432 genes. We identified nine genes whose expression was significantly altered during 22 days of culture with EM, and seven that were altered by CAM in that time. Four of those genes revealed similar behavior in cells treated with either of the 14-membered macrolides, but not JM. The products of these four genes may be candidates for mediating the ability of 14-membered macrolides to suppress chronic inflammation.

Effects of clarithromycin on cultured human nasal epithelial cells and fibroblasts

OBJECTIVE/METHODS

Long-term administration of clarithromycin has been reported to be effective in the treatment of chronic sinusitis. To investigate the mechanism underlying the anti-inflammatory activity of clarithromycin, the authors evaluated the effect of clarithromycin on the gene expression of proinflammatory cytokine and the DNA-binding activity of nuclear factor (NF)-kappa B in cultured human nasal epithelial cells and fibroblasts. Cells were incubated with endotoxin purified from nontypable Haemophilus influenzae or interleukin (IL)-1 beta in the presence of clarithromycin.

RESULTS

Northern blot analysis revealed that clarithromycin suppressed IL-1 beta gene expression in human nasal epithelial cells stimulated by H. influenzae endotoxin (HIE). Intercellular adhesion molecule-1 gene expression in nasal fibroblasts stimulated by IL-1 beta was also suppressed by clarithromycin. Furthermore, electrophoretic mobility shift assay demonstrated that clarithromycin reduced DNA-binding activity of NF-kappa B in both human nasal epithelial cells and fibroblasts stimulated by HIE or IL-1 beta, respectively.

CONCLUSION

The present results suggest that clarithromycin may reduce gene expression of proinflammatory cytokines and adhesion molecules from nasal mucosa at the transcriptional factor level and exert an anti-inflammatory effect on nasal mucosa in chronic sinusitis.

Roxithromycin and clarithromycin, 14-membered ring macrolides, potentiate the antitumor activity of cytotoxic agents against mouse B16 melanoma cells

We previously reported antiangiogenic activity of roxithromycin and clarithromycin, 14-membered ring macrolide antibiotics. In the present study, we examined the antitumor effects of roxithromycin and clarithromycin, alone and in combination with several cytotoxic drugs, on mouse B16BL6 melanoma cells in vivo and in vitro. Both roxithromycin and clarithromycin potentiated the inhibition of tumor growth induced by cyclophosphamide, cis-diamminedichloroplatinum(II), Adriamycin and vindesine in vivo. However, neither roxithromycin nor clarithromycin, altered the cytotoxicity of 4-hydroperoxycyclophosphamide, cis-diamminedichloroplatinum(II), Adriamycin or vindesine in an in vitro cell proliferation assay. These results suggest that the antiangiogenic activity of roxithromycin and clarithromycin may provide beneficial effects in combination with cytotoxic therapies against solid tumors.

Antiangiogenic and antitumor effects of 14-membered ring macrolides on mouse B16 melanoma cells

We examined the effects of macrolide antibiotics on tumor angiogenesis, tumor growth and metastasis in the B 16BL6 mouse melanoma and C57BL mouse system. Two 14-membered ring macrolide antibiotics, roxithromycin and clarithromycin, significantly reduced the dense capillary network area in a mouse dorsal air sac angiogenesis model, whereas a 15-membered ring macrolide, azithromycin, and a 16-membered ring macrolide, josamycin, did not show any inhibitory effect on angiogenesis at the same dose. Intraperitoneal administration of roxithromycin and clarithromycin at 50 mg/kg/day reduced the tumor size of B 16BL6 melanoma to about 41% and 56%, respectively, of that of the control, and significantly suppressed pulmonary metastasis of B16BL6 cells in a spontaneous system. Azithromycin and josamycin, on the other hand, did not inhibit tumor growth or pulmonary metastasis of B16BL6 cells. Immunohistochemistry revealed that roxithromycin and clarithromycin reduced the tumor vascularity and increased apoptosis of the tumor cells in vivo. These results suggest that 14-membered ring macrolides have antiangiogenic and antitumor effects and might have possible therapeutic applications.

Inhibitory effect of erythromycin on interleukin-8 secretion from exudative cells in the nasal discharge of patients with chronic sinusitis

OBJECTIVES

The mechanism of the efficacy of long-term low-dose macrolide therapy for chronic sinusitis is not fully understood. The authors studied the inhibitory effect of erythromycin on interleukin-8 (IL-8) secretion from exudative cells in the nasal discharge of patients with chronic sinusitis.

STUDY DESIGN AND METHODS

Exudative cells in the nasal discharge were isolated from six patients with nonallergic chronic sinusitis. The cells, more than 90% of which were neutrophils, were incubated with or without erythromycin in the presence of 10 micrograms/mL of lipopolysaccharide. The IL-8 concentrations in the culture supernatants were measured by enzyme-linked immunoassay.

RESULTS

The amount of secreted IL-8 in the absence of erythromycin was 682 +/- 226 pg/10(6) cells/24 h. The IL-8 secretion was significantly reduced to 66 +/- 15% and 46 +/- 13% of the control in the presence of 10(-6) and 10(-5) M of erythromycin, respectively.

CONCLUSION

Erythromycin may act as a biologic modulator that inhibits IL-8 secretion from exudative cells and thereby blocks the vicious circle of neutrophil recruitment and IL-8 generation in the inflammatory site in chronic sinusitis.

Clinical efficacy of the FLUTTER device for airway mucus clearance in patients with diffuse panbronchiolitis

Expectoration of mucus is important in preventing the development of airway inflammation in patients with diffuse panbronchiolitis (DPB). To evaluate the clinical efficacy of the FLUTTER device in clearing mucus from the airways of patients with DPB who have difficulty expectorating, we assessed pulmonary function and symptoms in patients treated with FLUTTER. Eight patients in a stable clinical condition with DPB were included in the study. The study was divided into two consecutive, 1-week periods. The initial week was an observation week. During the following week, patients used FLUTTER four times daily. Expectorated sputum was collected in a container and weighed every day during 2 weeks. Pulmonary function, partial oxygen pressure and partial carbon dioxide pressure in arterial blood were measured in all patients on the last day of the observation week and the FLUTTER treatment week. A symptom score for difficulty of expectoration was determined by questionnaire. A pneumothorax developed in one patient during using FLUTTER. The mean daily sputum weight and peak expiratory flow rate increased significantly after treatment with FLUTTER ( P< 0.04 and P< 0.02, respectively). Symptom score improved significantly after using FLUTTER ( P< 0.02). We conclude that the use of FLUTTER is effective in clearing mucus from the airways. However, the development of a pneumothorax may complicate use of the procedure in some cases.

Inhibitory effect of macrolides on interleukin-8 secretion from cultured human nasal epithelial cells

The mechanism of macrolide therapy in chronic sinusitis patients is unclear. The authors studied the effect of macrolides on interleukin (IL)-8 secretion from cultured human nasal epithelial cells. Epithelial cells harvested from the nasal polyps of patients with chronic sinusitis were primary-cultured, and secreted IL-8 in culture media was measured by enzyme immunoassay. The cells secreted considerable amounts of IL-8 constitutively and in response to lipopolysaccharide. The secretion was significantly inhibited by 10(-5) M of erythromycin, clarithromycin, roxithromycin, and josamycin. 10(-6) M erythromycin still showed the inhibitory effect, whereas the same concentration of josamycin did not. These results indicate that macrolide antibiotics may act as an immunomodulator to reduce IL-8 in inflammatory sites and, at least partially, account for the clinically discrepant effects between 14- and 16-membered ring macrolides in long-term low-dose therapy for chronic sinusitis.

Effects of long-term low-dose macrolide administration on neutrophil recruitment and IL-8 in the nasal discharge of chronic sinusitis patients

Effects of long-term low-dose macrolide administration were studied in patients with chronic sinusitis. Twelve patients with non-allergic chronic sinusitis were orally given 150 mg roxithromycin once a day without other treatments. The patients underwent computed tomography before and after the treatment, and paranasal sinus aeration was analyzed quantitatively. The number of neutrophils in the nasal smear was semiquantitatively assessed on a grading scale, and the IL-8 concentration in the nasal discharge was measured by enzyme immunoassay. The aeration of all four sinuses significantly improved, and recruited neutrophils and the IL-8 level in the nasal discharge were simultaneously reduced after the treatment. These findings suggest that long-term low-dose roxithromycin administration inhibits the positive feedback mechanism of neutrophil recruitment and IL-8 production by the recruited neutrophils, which is considered to be an essential cause of the prolongation of sinusitis.