Erythromycin inhibits transcriptional activation of NF-kappaB, but not NFAT, through calcineurin-independent signaling in T cells

Erythromycin: an alternative for the management of oral mucositis?

BACKGROUND

Oral mucositis (OM) is an important acute adverse effect of anticancer therapy. This condition presents high morbidity and may lead to the suspension of anticancer therapy.

MATERIAL AND METHODS

We reviewed the literature on the pathobiology of OM and the properties of erythromycin (EM), to consider the possibility of its use for the prevention and treatment of OM. We searched the PubMed, Scopus and Web of Science databases and selected complete articles published in English or Spanish that met the inclusion criteria. The search terms "erythromycin", "inflammation", "immunomodulation" and "oral mucositis" were used.

RESULTS

The control of free radicals, transcription factors and pro-inflammatory cytokines has been considered as the key to the management of OM. EM has the ability to modulate oxidative stress, acts on the transcriptional system and inhibits the production of several cytokines that have been directly implicated in OM pathobiology.

CONCLUSIONS

The present review suggests that EM could be effective in the treatment of OM. Experimental studies investigating the use of EM in OM should be encouraged.

Immunomodulatory Effects of Azithromycin Revisited: Potential Applications to COVID-19

The rapid advancement of the COVID-19 pandemic has prompted an accelerated pursuit to identify effective therapeutics. Stages of the disease course have been defined by viral burden, lung pathology, and progression through phases of the immune response. Immunological factors including inflammatory cell infiltration and cytokine storm have been associated with severe disease and death. Many immunomodulatory therapies for COVID-19 are currently being investigated, and preliminary results support the premise of targeting the immune response. However, because suppressing immune mechanisms could also impact the clearance of the virus in the early stages of infection, therapeutic success is likely to depend on timing with respect to the disease course. Azithromycin is an immunomodulatory drug that has been shown to have antiviral effects and potential benefit in patients with COVID-19. Multiple immunomodulatory effects have been defined for azithromycin which could provide efficacy during the late stages of the disease, including inhibition of pro-inflammatory cytokine production, inhibition of neutrophil influx, induction of regulatory functions of macrophages, and alterations in autophagy. Here we review the published evidence of these mechanisms along with the current clinical use of azithromycin as an immunomodulatory therapeutic. We then discuss the potential impact of azithromycin on the immune response to COVID-19, as well as caution against immunosuppressive and off-target effects including cardiotoxicity in these patients. While azithromycin has the potential to contribute efficacy, its impact on the COVID-19 immune response requires additional characterization so as to better define its role in individualized therapy.

Successful treatment of three patients with organizing pneumonia associated with rheumatoid arthritis using clarithromycin and prednisolone

Macrolides have anti-inflammatory effects and have been used to treat diffuse panbronchiolitis, bronchiectasis, and cystic fibrosis. Lately, several cases of cryptogenic organizing pneumonia (COP) and radiotherapy-related organizing pneumonia (OP) that were successfully treated with macrolides considering their anti-inflammatory effects were reported. We report three cases of OP associated with rheumatoid arthritis (RA) successfully treated with clarithromycin (CAM) and prednisolone (PSL). Case 1: A 70-year-old woman suffering from RA was admitted with cough and severe dyspnea. She was diagnosed with OP associated with RA on the basis of computed tomography (CT) findings and transbronchial lung biopsy results. She was successfully treated with PSL and cyclosporine A. At the exacerbation of OP, she was successfully treated with CAM and PSL. Case 2: A 74-year-old man suffering from COP visited our department with arthralgia and articular swellings. He was diagnosed with RA, which was thought to be associated with OP. He was successfully treated with CAM and PSL. Case 3: A 54-year-old man suffering from RA presented with an exacerbation of arthralgia and articular swellings and cough. He was diagnosed with OP associated with RA on the basis of CT findings. He was successfully treated with CAM and PSL. The present cases suggest that CAM and PSL treatment may be effective in some cases of OP associated with RA.

Long-term macrolides in diffuse interstitial lung diseases

In the present review we provide currently available evidence for the use of macrolides in the treatment of diffuse interstitial lung diseases (ILDs). Up to now, research on macrolides has mainly focused on three areas. First, macrolides have shown some promising results in cellular models and case reports as antifibrotic agents, by promoting autophagy and clearance of intracellular protein aggregates and acting as regulators of surfactant homeostasis. Secondly, macrolides have an immunomodulatory effect, which has been applied in some organising pneumonia cases. In particular, macrolides have been tested in association with systemic corticosteroids as steroid-sparing agents and alone as either first-line agents in mild cases or second-line agents where steroids were poorly tolerated or had failed. Thirdly, a recent area of research concerns the possible role of macrolides as modulators of lung microbiota and the host–microbiota interaction. This function has been particularly studied in idiopathic pulmonary fibrosis patients, in whom changes in microbiota have been proved to be associated with disease progression. However, the lack of high-quality studies makes the application of macrolide therapy in ILDs a field in which research should be conducted on a large scale.

Different Responses to Clarithromycin in Patients with Cryptogenic Organizing Pneumonia

Cryptogenic organizing pneumonia (COP) is an idiopathic interstitial pneumonia characterized by a subacute course and favorable prognosis with corticosteroids. However, some patients show resistance to steroids. Macrolides have been used with success in those patients showing resistance to steroids. A few reports showed treatment failure with macrolides in patients with COP who were resistant to steroids. In this report, we described two cases of COP who showed different responses to clarithromycin. One recovered completely, but the other gradually showed lung fibrosis with clarithromycin.

Clarithromycin (Biaxin®) extended-release tablet: a therapeutic review

Clarithromycin (Biaxin) extended-release tablets, an advanced generation macrolide, were recently introduced into the USA for the treatment of acute exacerbations of chronic bronchitis, community-acquired pneumonia and acute maxillary sinusitis. The reformulation is intended to improve both patient compliance and tolerability. The extended-release tablets allow convenient once-daily dosing (1000 mg). The extended-release formulation has been shown to be equivalent to the immediate-release formulation concerning area under the plasma concentration time curve. In comparative clinical trials for acute exacerbations of chronic bronchitis, community-acquired pneumonia and acute maxillary sinusitis, clarithromycin extended-release tablets were equivalent to the immediate-release formulation concerning clinical efficacy and bacterial eradication, with improved gastrointestinal tolerability. Similar efficacy and gastrointestinal tolerability results were demonstrated in a recent comparative study of clarithromycin extended-release formulation and amoxicillin-clavulanate in patients with acute exacerbations of chronic bronchitis. Clarithromycin extended-release 1000 mg daily has also been shown to be equivalent to levofloxacin 500 mg daily for the treatment of community-acquired pneumonia in a recent study. The macrolide class of antimicrobials, including clarithromycin extended-release, continues to be a safe and efficacious choice for the out-patient management of community-acquired bacterial respiratory tract infections.

Regulation of IL-17A production is distinct from IL-17F in a primary human cell co-culture model of T cell-mediated B cell activation

Improper regulation of B cell responses leads to excessive production of antibodies and contributes to the development of autoimmune disease. T helper 17 (Th17) cells also drive the development of autoimmune disease, but the role of B cells in shaping Th17 cell-mediated immune responses, as well as the reciprocal regulation of B cell responses by IL-17 family cytokines, remains unclear. The aim of this study was to characterize the regulation of IL-17A and IL-17F in a model of T cell-dependent B cell activation. Stimulation of primary human B cell and peripheral blood mononuclear cell (BT) co-cultures with α-IgM and a non-mitogenic concentration of superantigens for three days promoted a Th17 cell response as evidenced by increased expression of Th17-related gene transcripts, including Il17f, Il21, Il22, and Il23r, in CD4 T cells, as well as the secretion of IL-17A and IL-17F protein. We tested the ability of 144 pharmacologic modulators representing 91 different targets or pathways to regulate IL-17A and IL-17F production in these stimulated BT co-cultures. IL-17A production was found to be preferentially sensitive to inhibition of the PI3K/mTOR pathway, while prostaglandin EP receptor agonists, including PGE2, increased IL-17A concentrations. In contrast, the production of IL-17F was inhibited by PGE2, but selectively increased by TLR2 and TLR5 agonists. These results indicate that IL-17A regulation is distinct from IL-17F in stimulated BT co-cultures and that this co-culture approach can be used to identify pathway mechanisms and novel agents that selectively inhibit production of IL-17A or IL-17F.

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.

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.

Macrolide therapy in respiratory viral infections

BACKGROUND

Macrolides have received considerable attention for their anti-inflammatory and immunomodulatory actions beyond the antibacterial effect. These two properties may ensure some efficacy in a wide spectrum of respiratory viral infections. We aimed to summarize the properties of macrolides and their efficacy in a range of respiratory viral infection.

METHODS

A search of electronic journal articles through PubMed was performed using combinations of the following keywords including macrolides and respiratory viral infection.

RESULTS

Both in vitro and in vivo studies have provided evidence of their efficacy in respiratory viral infections including rhinovirus (RV), respiratory syncytial virus (RSV), and influenza virus. Much data showed that macrolides reduced viral titers of RV ICAM-1, which is the receptor for RV, and RV infection-induced cytokines including IL-1β, IL-6, IL-8, and TNF-α. Macrolides also reduced the release of proinflammatory cytokines which were induced by RSV infection, viral titers, RNA of RSV replication, and the susceptibility to RSV infection partly through the reduced expression of activated RhoA which is an RSV receptor. Similar effects of macrolides on the influenza virus infection and augmentation of the IL-12 by macrolides which is essential in reducing virus yield were revealed.

CONCLUSION

This paper provides an overview on the properties of macrolides and their efficacy in various respiratory diseases.

[Azithromycin as an adjuvant therapy in cryptogenic organizing pneumonia]

There are literature data about the immunomodulatory properties of some macrolides in cryptogenic organizing pneumonia (COP) as an alternative to corticosteroids in mild disease or as adjuvant to standard therapy. A sixty-year-old female, with a controlled intrinsic asthma, presented with COP and recurrent respiratory exacerbations despite corticosteroid and immunossupressant therapy. Azithromycin (500mg, on alternate days) as an adjuvant to steroids was then started, with clinical and functional improvement and regression of lung infiltrates. Withdrawal of steroids was possible in one year, without evidence of relapse in the next six months. Azithromycin was maintained (three times per week) with no documentation of adverse side effects. This clinical case reinforces the potential role of macrolides anti-inflammatory properties in COP as corticosteroids adjuvant therapy.

Anti-Inflammatory benefits of antibiotic-induced neutrophil apoptosis: tulathromycin induces caspase-3-dependent neutrophil programmed cell death and inhibits NF-kappaB signaling and CXCL8 transcription

Clearance of apoptotic neutrophils is a central feature of the resolution of inflammation. Findings indicate that immuno-modulation and induction of neutrophil apoptosis by macrolide antibiotics generate anti-inflammatory benefits via mechanisms that remain obscure. Tulathromycin (TUL), a new antimicrobial agent for bovine respiratory disease, offers superior clinical efficacy for reasons not fully understood. The aim of this study was to identify the immuno-modulating effects of tulathromycin and, in this process, to establish tulathromycin as a new model for characterizing the novel anti-inflammatory properties of antibiotics. Bronchoalveolar lavage specimens were collected from Holstein calves 3 and 24 h postinfection, challenged intratracheally with live Mannheimia haemolytica (2 × 10(7) CFU), and treated with vehicle or tulathromycin (2.5 mg/kg body weight). Terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling (TUNEL) staining and enzyme-linked immunosorbent assay (ELISA) revealed that tulathromycin treatment significantly increased leukocyte apoptosis and reduced levels of proinflammatory leukotriene B(4) in M. haemolytica-challenged calves. In vitro, tulathromycin concentration dependently induced apoptosis in freshly isolated bovine neutrophils from healthy steers in a capase-3-dependent manner but failed to induce apoptosis in bovine fibroblasts, epithelial cells, and endothelial cells, as well as freshly isolated bovine blood monocytes and monocyte-derived macrophages. The proapoptotic effects of TUL were also, in part, drug specific; equimolar concentrations of penicillin G, oxytetracycline, and ceftiofur failed to cause apoptosis in bovine neutrophils. In addition, tulathromycin significantly reduced levels of phosphorylated IκBα, nuclear translocation of NF-κB p65, and mRNA levels of proinflammatory interleukin-8 in lipopolysaccharide (LPS)-stimulated bovine neutrophils. The findings illustrate novel mechanisms through which tulathromycin confers anti-inflammatory benefits.

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.

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?

[Usefulness of macrolides as anti-inflammatories in respiratory diseases]

The macrolides are antibiotics that, besides their anti-bacterial action, have an anti-inflammatory effect, by decreasing the activity of the immune cells and bacteria cell changes. An increase the survival of patients suffering from diffuse panbronchiolitis was already seen in the 1980s, after being treated with erythromycin. Currently, the use of macrolides in various chronic inflammatory diseases has increased significantly. Clinical improvements associated to the administration of macrolides have been observed in diseases such as, cystic fibrosis, asthma, and bronchiectasis. However, despite the apparent clinical benefit they seem to provide, the published results up until now are controversial and conclusive results are unable to be obtained. This means that further clinical trials are necessary to confirm or refute the long-term use of these drugs, which are not free of adverse effects, mainly the appearance of resistant bacteria.

Novel inhibitors of the calcineurin/NFATc hub - alternatives to CsA and FK506?

The drugs cyclosporine A (CsA) and tacrolimus (FK506) revolutionized organ transplantation. Both compounds are still widely used in the clinic as well as for basic research, even though they have dramatic side effects and modulate other pathways than calcineurin-NFATc, too. To answer the major open question - whether the adverse side effects are secondary to the actions of the drugs on the calcineurin-NFATc pathway - alternative inhibitors were developed. Ideal inhibitors should discriminate between the inhibition of (i) calcineurin and peptidyl-prolyl cis-trans isomerases (PPIases; the matchmaker proteins of CsA and FK506), (ii) calcineurin and the other Ser/Thr protein phosphatases, and (iii) NFATc and other transcription factors. In this review we summarize the current knowledge about novel inhibitors, synthesized or identified in the last decades, and focus on their mode of action, specificity, and biological effects.

In vitro effects of erythromycin on RANKL and nuclear factor-kappa B by human TNF-alpha stimulated Jurkat cells

The receptor activator of NF-kappaB ligand (RANKL) and its signal downstream nuclear factor-kappaB (NF-kappaB) are critical regulators for immune responses as well as bone remodeling. The present study aimed to examine the effects of erythromycin (EM) on the activation of RANKL, correlation with NF-kappaB expression, proliferation and apoptosis of human Jurkat T cells. Jurkat T cells were pretreated with 100 pmol/l tumor necrosis factor-alpha (TNF-alpha) for 1 h followed by various concentrations of EM for 24 h. The mRNA expressions of RANKL and NF-kappaB were examined by RT-PCR. The protein expression of NF-kappaB was analyzed by Western blot. The protein level of RANKL was examined by flow cytometry, immunofluorescence microscopy and Western blot analyses. We also examined proliferation of Jurkat T cells by MTT assay, apoptosis by flow cytometry analysis after staining with PI and morphological observation after AO/EB staining. The results showed that EM inhibited TNF-alpha-induced expressions of RANKL and NF-kappaB at both mRNA and protein levels in a concentration-dependent manner. The expression of RANKL was correlated with the expression of NF-kappaB. Moreover, EM influenced the proliferation and apoptosis of human Jurkat T cells. These data suggest that EM acts as an anti-inflammatory agent not only to interact with the expression of NF-kappaB and the proliferation of human Jurkat T cells, but also to reduce the level of RANKL.

Immunomodulatory effects of erythromycin and its derivatives on human T-lymphocyte in vitro

To elucidate the immunomodulatory mechanisms of macrolides, we investigated here the effects of erythromycin (EM) and its derivatives, 1 and 2, which show no antibacterial activity, on the proliferation and the activation of the transcription factor nuclear factor-kappaB (NF-kappaB) in Jurkat T cells. MTT assay revealed that EM, 1 and 2 could inhibit T lymphocyte proliferation markedly. Flow cytometry and TUNEL analysis showed EM (30 microg/mL-100 microg/mL) and 1 (3 microg/mL-30 microg/mL) could induce T lymphocyte apoptosis, 2 (3 microg/mL-30 microg/mL) induced a cell cycle arrest in G(2)/M. RT-PCR and Western blotting analysis conformed that EM and its two derivatives could inhibit the expressions of NF-kappaB mRNA and protein. Taken together, these data suggest EM and its derivatives, 1 and 2, have immunomodulatory effect, presumably via an interaction with the NF-kappaB expression, inhibiting the proliferation of T lymphocyte, implicating an approach for the development of new drugs for treating inflammatory diseases.

Macrolide antibiotics as immunomodulatory medications: proposed mechanisms of action

Macrolide antibiotics administered in sub-antimicrobial doses improve pulmonary function and decrease exacerbation frequency for persons with diffuse panbronchiolitis or cystic fibrosis. Data also suggest a beneficial effect of macrolide antibiotics in the treatment of steroid dependent asthma. Many potential immunomodulatory effects of macrolide antibiotics have been reported including the ability to down-regulate prolonged inflammation, decreasing airway mucus secretion, inhibiting bacterial biofilm, decreasing the production of reactive oxygen species, inhibiting neutrophil activation and mobilization, accelerating neutrophil apoptosis, and blocking the activation of nuclear transcription factors. Macrolides initially decrease, then increase, and have finally a sustained suppression of cytokine secretions from normal human bronchial epithelial cells through inhibition and activation of extracellular signal-regulated kinases (ERK) and then reversibly retard cell proliferation probably through ERK. Consistent with this, macrolide antibiotics possibly reduce mucin production as well as neutrophil migration by interfering with ERK signal transduction.

The inhibitory effects of macrolide antibiotics on bone remodeling in chronic rhinosinusitis

OBJECTIVE

To investigate the effect of nasal mucosal inflammation on bone remodeling and the inhibitory effect of macrolide antibiotics on bone remodeling through the inhibition of receptor activator of nuclear factor-kappaB ligand (RANKL) and macrophage colony-stimulating factor (M-CSF).

STUDY DESIGN AND SETTING

Human nasal fibroblasts were primary-cultured from nasal polyp. After interleukin (IL)-1beta stimulation of fibroblasts with or without macrolide pretreatment, real-time polymerase chain reaction for RANKL messenger RNA (mRNA) and enzyme-linked immunosorbent assay for M-CSF were performed at various intervals. Peripheral blood mononuclear cells (PBMCs) were cultured for 10 days with M-CSF only, M-CSF plus RANKL, or macrolide antibiotic plus M-CSF and RANKL.

RESULTS

IL-1beta stimulation of nasal polyp fibroblasts induced expression of RANKL mRNA and secretion of M-CSF. Macrolide antibiotics reduced RANKL mRNA and M-CSF expression by nasal polyp fibroblasts in a dose-dependent manner, and inhibited osteoclastogenesis from PBMCs.

CONCLUSION

Nasal fibroblasts stimulated with IL-1beta may take on the role of osteoblasts in osteoclastogenesis, which may be inhibited by macrolide antibiotics.

Macrolides in cystic fibrosis

Cystic fibrosis (CF) results in chronic pulmonary disease in the majority of patients resulting from the production of viscous secretions and impairment of mucociliary clearance due to alterations in airway surface liquid. Chronic infection results, and the combination of tissue damage by pathogenic organisms and a robust host inflammatory response leads to the development of bronchiectasis and progressive lung disease. Macrolide antibiotics have demonstrated efficacy in diffuse panbronchiolitis, a disease that shares many similarities to CF, and this has generated interest in the use of these agents in patients who have CF. The authors review the data that demonstrate clinical benefits of long-term azithromycin administration in patients who have CF and discuss potential host- and pathogen-related explanations for the positive therapeutic effect.

Is there a role for inhaled corticosteroids and macrolide therapy in bronchiectasis?

Bronchiectasis is characterised by permanent dilatation of the bronchi that arises from chronic inflammation predominantly caused by bacterial infection. This condition remains a major cause of excess respiratory morbidity and treatment is generally only partly successful. There is an urgent need for improved anti-inflammatory medication to treat bronchiectasis. Two potentially useful therapies are inhaled corticosteroids (ICS) and macrolides. The clinical trials that have been performed in bronchiectasis with these two medications can be considered to be preliminary data. This article reviews the anti-inflammatory properties, clinical efficacy and adverse effects of ICS and macrolides.ICS have a large number of potent anti-inflammatory properties. ICS remain the first-line treatment in asthma, reduce exacerbations in chronic obstructive pulmonary disease, and may improve lung function and symptoms in cystic fibrosis (CF). Four small clinical trials have assessed the effect of high-dose ICS on bronchiectasis. The main reported effect of these trials was a reduction in sputum volume and this may be a marker of decreased airway inflammation. Other possible benefits included decreased cough and sputum inflammatory cells/biomarkers. ICS have a relatively high prevalence of local adverse effects, and may be associated with ocular complications and osteoporosis. These adverse effects can be minimised by prescribing low doses of the medication. Macrolides have both antibacterial and immunomodulatory properties. Macrolides have less marked immunosuppressive properties than corticosteroids, and effects include decreasing mucous production, inhibiting virulence factors and biofilm formation of Pseudomonas aeruginosa, decreasing leukocyte numbers and altering inflammatory mediator release. Macrolides have been shown to be extremely effective in the treatment of diffuse panbronchiolitis, improve lung function and symptoms in asthma and CF, and reduce nasal polyps and secretions in sinusitis. Five small clinical trials have assessed the effect of macrolides on bronchiectasis. Reported benefits include reduced sputum volume, improved lung function and better symptom control. Macrolides are generally well tolerated, although they do have a number of drug interactions. There are concerns about the development of resistance, especially to non-tuberculous mycobacteria, with prolonged macrolide use. The evidence available suggests that both medications have a role in the management of bronchiectasis. More definitive trials of ICS and macrolides in bronchiectasis will clarify the likely benefit of these therapies.

Macrolides inhibit IL17-induced IL8 and 8-isoprostane release from human airway smooth muscle cells

Lung transplantation is hampered by bronchiolitis obliterans syndrome (BOS), although recently azithromycin treatment has a published response rate of about 42% in patients with established BOS. We linked this improvement to a reduction in airway neutrophilia and IL8. In the present study, we further investigated the intracellular mechanisms of azithromycin, looking at the possible involvement of mitogen-activated-protein kinases (MAPK) and oxidative stress. Simultaneously, currently used immunosuppressive agents were investigated. Human primary airway smooth muscle cells were stimulated with IL17 and incubated with increasing concentrations of steroids, immunosuppressive agents (tacrolimus, cyclosporine and rapamycin) or macrolides (erythromycin and azithromycin). We measured supernatant IL8 protein, 8-isoprostane and cell lysate MAPK. IL17-induced IL8 production was decreased by both erythromycin and azithromycin. In nonstimulated condition, IL8 production only increased at the highest dose of azithromycin. Dexamethasone failed to attenuate IL8 production, whereas immunosuppressive agents significantly increased IL8 production in both IL17-stimulated and nonstimulated conditions. 8-isoprostane production and MAPK activation proved to be decreased by the macrolides. We conclude that macrolides (but not steroids/immunosuppressive agents) inhibit IL17-induced IL8 production in human primary airway smooth muscle cells via a reduction in MAPK activation and 8-isoprostane production. In BOS patients, these phenomena may explain the anti-inflammatory effects of azithromycin.

Macrolide immunomodulatory effects and symptom resolution in acute exacerbation of chronic bronchitis and acute maxillary sinusitis: a focus on clarithromycin

Bacterial respiratory tract infections are common in the primary care setting and patients often seek the assistance of a healthcare professional in order to achieve resolution of their symptoms. Antibiotic agents that offer rapid symptom relief, in addition to excellent bacteriological and clinical cure, are highly desired. Macrolides have proven to be highly effective in treating acute bacterial exacerbations of chronic bronchitis and acute maxillary sinusitis. In addition, immunomodulatory effects that may contribute to symptom resolution have been reported. This article reviews current literature on symptom resolution in acute bacterial exacerbations of chronic bronchitis and acute maxillary sinusitis, with a focus on clarithromycin, and explores the potential mechanisms that may contribute to this action.

Erythromycin differentially inhibits lipopolysaccharide- or poly(I:C)-induced but not peptidoglycan-induced activation of human monocyte-derived dendritic cells

Erythromycin (EM) has attracted attention because of its anti-inflammatory effect. Because dendritic cells (DCs) are the most potent APCs involved in numerous pathologic processes including innate immunity, we examined effects of EM on the activation of human DCs by pathogen-derived stimuli. Monocyte-derived DCs were pretreated with EM and subsequently stimulated with peptidoglycan, polyriboinosinic:polyribocytidylic acid (poly(I:C)), or LPS. The activation of DCs was assessed by surface molecule expression and cytokine production. To reveal the signaling pathways affected by EM, TLR expression, NF-kappaB, IFN regulatory factor-3, and AP-1 activation were examined. EM inhibited costimulatory molecule expression and cytokine production that was induced by poly(I:C) and LPS but not by peptidoglycan. EM pretreatment down- and up-regulated mRNA levels of TLR3 and TLR2, respectively, but did not affect that of TLR4. EM suppressed IFN regulatory factor-3 activation and IFN-beta production but not AP-1 activation induced by poly(I:C) and LPS. The inhibitory effect of EM on NF-kappaB activation was observed only in poly(I:C)-stimulated DCs. EM selectively suppressed activation of DCs induced by LPS and poly(I:C) in different ways, suggesting that the immuno-modulating effects of EM depend on the nature of pathogens. These results might explain why EM prevents the virus-induced exacerbation in the chronic inflammatory respiratory diseases and give us the clue to design new drugs to treat these diseases.

Macrolide antibiotics modulate ERK phosphorylation and IL-8 and GM-CSF production by human bronchial epithelial cells

Macrolide antibiotics decrease proinflammatory cytokine production in airway cells from subjects with chronic airway inflammation. However, in subjects with chronic obstructive pulmonary disease, short-term azithromycin (AZM) therapy causes a transient early increase in the blood neutrophil oxidative burst followed by a decrease in inflammatory markers with longer administration. We studied the effects of clarithromycin (CAM) and AZM on proinflammatory cytokine production from normal human bronchial epithelial (NHBE) cells. CAM decreased IL-8 over the first 6 h and then significantly increased interleukin (IL)-8 at 12–72 h after exposure ( P < 0.0001). AZM also increased IL-8 at 24 and 48 h, and CAM increased granulocyte-macrophage colony-stimulating factor at 48 h. In the presence of LPS, both CAM and AZM dose-dependently increased IL-8 secretion over 24 h, but after 5 days of exposure to 10 μg/ml CAM there is suppression of IL-8 ( P < 0.001). PD-98059, an inhibitor of MAP kinase/ERK kinase, inhibited CAM-induced IL-8 ( P < 0.0001) and GM-CSF ( P < 0.01) release. The p38 MAP kinase inhibitor SB-203580 increased CAM-induced IL-8 release ( P < 0.001), and the c-jun NH2-terminal kinase inhibitor SP-600125 had no effect on IL-8. At 120 min and 6 h, CAM increased phospho-ERK1/2 (pERK) but not phospho-p38 or phospho-JNK. Over the first 90 min, CAM at 10 μg/ml inhibited pERK and then increased pERK in parallel with measured IL-8 secretion. After daily CAM exposure for 5 days, both IL-8 and pERK returned to baseline. The p38 MAP kinase inhibitor, SB-203580 increased ERK phosphorylation and IL-8 secretion. These results suggest that macrolide antibiotics can differentially modulate proinflammatory cytokine secretion in NHBE cells, in part through ERK.

Macrolides: a treatment alternative for bronchiolitis obliterans organizing pneumonia?

Some macrolides have been found to exert anti-inflammatory effects. Lung diseases such as asthma, panbronchiolitis, cystic fibrosis, and bronchiectasis are thought to respond to the immunomodulatory properties of macrolides. We report three cases of idiopathic bronchiolitis obliterans organizing pneumonia, now called cryptogenic organizing pneumonia, and three cases of radiation-related bronchiolitis obliterans organizing pneumonia that responded to macrolide therapy. An explanation of why macrolides may have anti-inflammatory effects in patients with these syndromes is discussed. These cases help to reinforce accumulating data that macrolides are beneficial as anti-inflammatory agents and organizing pneumonia may be another pulmonary disease that can benefit from such therapy.

Macrolides in cystic fibrosis

Macrolide antibiotics have been licensed since the 1950s and have an important role in the treatment of a diverse range of infectious diseases. Macrolide antibiotics have antibacterial activity against gram-positive bacteria, some gram-negative bacteria and intracellular pathogens. The spectrum of antibacterial activity combined with excellent intracellular and tissue penetration has led to the extensive use of this class of drugs in respiratory disease. Macrolide antibiotics also have demonstrated anti-inflammatory properties in various in vitro and in vivo model systems. Novel antimicrobial and anti-inflammatory properties of macrolide may result in clinical benefits, particularly in conditions where the infectious agent is inherently resistant to macrolides. Three randomized control trials have demonstrated improved lung function in patients treated with the macrolide antibiotic, azithromycin. Azithromycin was generally well tolerated and resulted in reduction in the inflammatory response which may be due to an immunomodulatory role. Short term studies (three to six months) have not demonstrated the development of increased bacterial resistance or the emergence of new pathogens following azithromycin.

Macrolides and airway inflammation in children

For more than 20 years macrolide antibiotics have been used to treat chronic inflammatory airway diseases based on their immunomodulatory activity. Macrolide antibiotics down-regulate damaging prolonged inflammation as well as increase mucus clearance, decrease bacterial virulence and prevent biofilm formation. Initially shown to decrease morbidity and mortality in diffuse panbronchiolitis and in steroid-dependent asthma, long-term macrolide therapy has now been shown to significantly reduce exacerbations and improve lung function and quality of life in children with cystic fibrosis. They have also proven beneficial in Japanese children and adults with chronic sinobronchitis especially when there is nasal polyposis. Long-term macrolides have also proven clinically beneficial in some patients with plastic bronchitis. Adverse reactions are few and generally self-limited when used at the recommended dosage for immunomodulation.

Erythromycin exerts in vivo anti-inflammatory activity downregulating cell adhesion molecule expression

1. Macrolides have long been used as anti-bacterial agents; however, there is some evidence that may exert anti-inflammatory activity. Therefore, erythromycin was used to characterize the mechanisms involved in their in vivo anti-inflammatory activity. 2. Erythromycin pretreatment (30 mg kg(-1) day(-1) for 1 week) reduced the lipopolysaccharide (LPS; intratracheal, 0.4 mg kg(-1))-induced increase in neutrophil count and elastase activity in the bronchoalveolar lavage fluid (BALF) and lung tissue myeloperoxidase activity, but failed to decrease tumor necrosis factor-alpha and macrophage-inflammatory protein-2 augmented levels in BALF. Erythromycin pretreatment also prevented lung P-selectin, E-selectin, intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) mRNA upregulation in response to airway challenge with LPS. 3. Mesentery superfusion with LPS (1 mug ml(-1)) induced a significant increase in leukocyte-endothelial cell interactions at 60 min. Erythromycin pretreatment abolished the increases in these parameters. 4. LPS exposure of the mesentery for 4 h caused a significant increase in leukocyte rolling flux, adhesion and emigration, which were inhibited by erythromycin by 100, 93 and 95%, respectively. 5. Immunohistochemical analysis showed that LPS exposure of the mesentery for 4 h caused a significant enhancement in P-selectin, E-selectin, ICAM-1 and VCAM-1 expression that was downregulated by erythromycin pretreatment. 6. Flow cytometry analysis indicated that erythromycin pretreatment inhibited LPS-induced CD11b augmented expression in rat neutrophils. 7. In conclusion, erythromycin inhibits leukocyte recruitment in the lung and this effect appears mediated through downregulation of CAM expression. Therefore, macrolides may be useful in the control of neutrophilic pulmonary diseases.

Macrolides in the treatment of asthma and cystic fibrosis

Asthma and cystic fibrosis are two respiratory diseases characterized by chronic inflammation, leading to remodelling of the airways. Macrolides are widely used antibiotics, with a peculiar anti-inflammatory effect. On the basis of the methodologies used by the Cochrane collaboration, this review discusses the evidence for their long-term use as anti-inflammatory agents in these two diseases. Three randomized-controlled trials (RCTs) were identified for both asthma and cystic fibrosis. A positive effect of macrolides on reducing eosinophil numbers and markers of eosinophilic inflammation was demonstrated in patients with asthma. Data on cystic fibrosis demonstrated an effect on lung function with an increase of 5.4% in forced vital capacity (FVC) in patients treated with macrolide vs. placebo, but without a significant effect on FEV1. Side-effects were rare, mild and reversible on withdrawal of treatment. Although preliminary data from small studies are promising, the role of macrolides in the treatment of these chronic disorders needs to be more firmly established with larger, well-designed trials, targeted to investigate major clinical outcomes.

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.

Gemifloxacin inhibits cytokine secretion by lipopolysaccharide stimulated human monocytes at the post-transcriptional level

The fluroquinolone gemifloxacin was examined for its capacity to modulate secretion of cytokines by human monocytes stimulated with lipopolysaccharide (LPS). Monocytes from six male and two female healthy volunteers were stimulated with LPS, exposed to gemifloxacin and the amounts of secreted IL-1 alpha, IL-1 beta, IL-6, IL-10 and TNF-alpha measured at 3, 6 and 24 h. The results revealed that LPS alone increased secretion of each cytokine significantly. Treatment of the LPS-stimulated monocytes with gemifloxacin resulted in a significant inhibition (p < 0.01) of secretion of each of the cytokines from monocytes of the eight volunteers. Nuclear extracts of the human monocyte cell line, THP-1, were used in the electrophoretic mobility shift assay to determine whether gemifloxacin affects nuclear factor-kappa B (NF-kappa B) activation. In addition, RNA from THP-1 cells was used in Northern blots to determine whether inhibition of secretion of IL-1 beta and TNF-alpha by gemifloxacin occurred at the transcription or translation level. Whereas LPS induced a rapid increase in NF-kappa B activation, gemifloxacin alone did not. Gemifloxacin did not affect the kinetics or decrease the extent of activation. Northern blots indicated that the inhibitory activity of gemifloxacin occurred post-transcription. Thus, gemifloxacin may modulate the immune response by altering secretion of cytokines by human monocytes. Although the concentrations of gemifloxacin used were higher than those observed in the serum of human volunteers treated with the dose under clinical development, it should be taken into consideration that concentrations at tissue and intracellular levels may be considerably higher than serum concentrations.

Evaluation of the Medical and Surgical Treatment Of Chronic Rhinosinusitis: A Prospective, Randomised, Controlled Trial

OBJECTIVES

To conduct the first prospective, randomized, controlled trial evaluating and comparing the medical and surgical treatment of polypoid and nonpolypoid chronic rhinosinusitis (CRS).

MATERIALS AND METHODS

Ninety patients with CRS were equally randomized either to medical or surgical therapy. All patients underwent pre- and posttreatment assessments of visual analogue score (VAS), the Sinonasal Outcome Test-20 (SNOT-20), the Short Form 36 Health Survey (SF-36), nitric oxide (NO), acoustic rhinometry, saccharine clearance time (SCT), and nasal endoscopy. Each patient had three assessments: before starting the treatment, after 6 months, and, finally, after 1 year.

RESULTS

Both the medical and surgical treatment of CRS significantly improved almost all the subjective and objective parameters of CRS (P <.01), with no significant difference being found between the medical and surgical groups (P >.05), except for the total nasal volume in CRS (P <.01) and CRS without polyposis (P <.01) groups, in which the surgical treatment demonstrated greater changes.

CONCLUSION

CRS should be initially targeted with maximal medical therapy (e.g., a 3 month course of a macrolide antibiotic, douche, and topical steroid), with surgical treatment being reserved for cases refractory to medical therapy. The presence of nasal polyps is not a poor prognostic factor for the efficacy of CRS therapy, either surgical or medical.

The effects of macrolides on inflammatory cells

Bronchial epithelial damage and mucus hypersecretion are characteristic features of chronic airway inflammation that can impair mucociliary clearance and can cause recurrent or persistent respiratory infection. In response to chemoattractants produced by damaged or inflamed tissue, neutrophils move through sequential steps of recruitment, migration, accumulation, and adhesion to endothelial and bronchial epithelial cells. Neutrophils engage in bacteriocidal activity by phagocytosis, release of lysosomal enzymes, and generation of reactive oxygen species, and they synthesize and release proinflammatory cytokines. Data confirm that many macrolide antibiotics have nonbactericidal properties that include inhibiting inflammatory cell chemotaxis, cytokine synthesis, adhesion molecule expression, and reactive oxygen species production. Macrolides also can decrease airway mucus hypersecretion in patients with diffuse panbronchiolitis, chronic sinusitis, and chronic bronchitis. Macrolides accumulate in neutrophils and macrophages at significantly higher concentrations than in extracellular fluid. This article discusses the action of macrolides on neutrophil accumulation, immune complex-mediated production of nitric oxide, mucin production, and the expanded therapeutic role of macrolides as biological response modifiers.

Erythromycin inhibits wear debris-induced osteoclastogenesis by modulation of murine macrophage NF-kappaB activity

Activation of nuclear factor kappa B (NF-kappaB) signaling in response to cell stimulation by wear debris may be critical in the pathogenesis of aseptic loosening. Erythromycin (EM), a macrolide antibiotic, has been shown to effectively suppress some types of inflammatory reactions. In this study, we examined the effect of EM on wear debris-induced osteoclastic bone resorption in vitro. EM inhibited Ca+ release from neonatal calvaria co-cultured with conditioned medium from mouse RAW264.7 macrophages activated by wear debris. Inhibition of Ca+ release was associated with a decreased number of tartrate-resistant acid phosphatase (TRAP)-positive cells in cultured bones. To investigate the mechanism whereby EM inhibits bone-resorption, RAW cells were incubated with wear debris in the presence EM. Real time RT-CR analysis revealed that EM (5 microg/ml) significantly inhibited mRNA expression of NF-kappaB, cathepsin K (CPK), IL-1beta and TNFalpha, but not RANK in RAW cells stimulated with wear debris. Furthermore, electrophoretic mobility-shift assay showed that EM (0.2 microg-5 microg/ml) could reduce DNA-binding activity of NF-kappaB in RAW cells stimulated with wear debris. The inhibition of inflammatory osteoclastogenesis by EM treatment was further confirmed by an osteoclast (OC) formation assay using primary cultures of mouse bone marrow progenitor cells stimulated with macrophage colony-stimulating factor and RANK ligand (RANKL). EM treatment (5 microg/ml) resulted in more than 70% reduction in multinucleated OC formation and 50% reduction of TRAP+ cells by bone marrow progenitor cells. Our findings support that EM suppresses wear debris-induced osteoclastic bone resorption by, at least, down-regulation of NF-kappaB signaling pathway. It appears that EM represents a potential therapeutic candidate for the treatment and prevention of aseptic loosening.

Antibiotic cyclic AMP signaling by "primed" leukocytes confers anti-inflammatory cytoprotection

The mechanism underlying anti-inflammatory effects of macrolide antibiotics remains uncertain. In this study, we first show the evidences concerning the possible link between leukocytic cyclic adenosine monophosphate (cAMP) signaling and the mechanism of anti-inflammatory, cytoprotective actions of macrolides. The clinical range of macrolides (i.e., erythromycin, roxithromycin, and clarithromycin) preferentially inhibited nuclear factor-kappaB activation mediated by reactive oxygen intermediates, inducing cAMP-dependent signaling [i.e., cAMP and cAMP-responsive element-binding protein (CREB)] by "primed" but not "resting" leukocytes. In this context, cAMP/CREB inhibition with adenosine 3':5'-cyclic monophosphothioate, rp-isomer (rp-cAMPs) and CREB decoy oligonucleotides reduced the anti-inflammatory actions of macrolides. These results thus indicate that macrolide-induced cAMP/CREB signaling, selectively by primed leukocytes, plays a major role in the mechanism of anti-inflammatory actions of macrolides.

Severe erythema nodosum due to Behçet's disease responsive to erythromycin

A patient with severe erythema nodosum due to Behçet's disease is reported on here. Erythema nodosum lesions did not respond to classical treatments; however, they cleared after erythromycin treatment, which was prescribed for the treatment of coincidental erythrasma. Erythromycin treatment appears to be an effective treatment option in erythema nodosum. The hypothetical anti-inflammatory effects of erythromycin, besides its antibiotic properties, are reviewed and discussed to explain such a clinical improvement.

The scavenger receptor, cysteine-rich domain-containing molecule gp-340 is differentially regulated in epithelial cell lines by phorbol ester

Gp-340 is a glycoprotein belonging to the scavenger receptor cysteine rich (SRCR) group B family. It binds to host immune components such as lung surfactant protein D (SP-D). Recent studies found that gp-340 interacts directly with pathogenic microorganisms and induces their aggregation, suggesting its involvement in innate immunity. In order to investigate further its potential immune functions in the appropriate cell lines, the expression of gp-340 in four conventional immune cell lines (U937, HL60, Jurkat, Raji), and two innate immune-related epithelial cell lines (A549 derived from lung and AGS from stomach), was examined by RT-PCR and immunohistochemistry. The resting immune cell lines showed weak or no gp-340 mRNA expression; while the two epithelial cell lines expressed gp-340 at much higher level, which was differentially regulated by phorbol myristate acetate (PMA) treatment. In the A549 cells, gp-340 was up-regulated along with the PMA-induced proinflammatory expression of both IL-6 and IL-8. In AGS cells, PMA down-regulation of gp-340 was seen in parallel with an up-regulation of the two mature gastric epithelial specific proteins TFF1 (trefoil factor 1) and TFF2, which are implicated as markers of terminal differentiation. Analysis of the distribution of gp-340, together with the TFFs and SP-D in normal lung and gastric mucosa, supported further our in vitro data. We conclude that the differential regulation of gp-340 in the two epithelial cell lines by PMA indicates that gp-340 s involvement in mucosal defence and growth of epithelial cells may vary at different body locations and during different stages of epithelial differentiation.