Macrolide antibiotics as immunomodulatory medications: proposed mechanisms of action

Clarithromycin in adult-onset still's disease: a potentially useful therapeutic

Adult-onset Still's disease (AOSD), an autoinflammatory syndrome of unknown etiology, typically manifests with spiking fevers, polyarthritis, and characteristic evanescent rash. We describe a young woman with AOSD complicated by calf fasciitis that serendipitously responded to clarithromycin administered for another indication. Remarkable improvement followed rechallenges with clarithromycin for subsequent AOSD flares. In addition to their antibacterial actions, macrolides demonstrate immunomodulatory effects, including suppression of proinflammatory cytokine production and neutrophil action. Previous clinical trials provide promising preliminary evidence of a therapeutic effect of macrolides in chronic inflammatory diseases. Although AOSD pathogenesis remains unclear, a role for dysregulation of innate immunity is supported by recent literature. Based on this possible innate immune mechanism, we suspect that macrolides may have induced a therapeutic response in this patient with AOSD. A clinical trial is warranted to establish or refute their therapeutic efficacy.

Virulence-suppressing effects of linezolid on methicillin-resistant Staphylococcus aureus: possible contribution to early defervescence

In the present study, immunomodulatory effects of linezolid (LZD) on methicillin-resistance Staphylococcus aureus (MRSA) infections were evaluated. We have retrospectively reviewed treatment effects of LZD on 52 patients with severe MRSA infections. Sixty-four percent of the febrile patients demonstrated significant defervescence within 3 days, despite the presence of positive culture results. We speculated that this finding might be due to early anti-inflammatory effects of LZD, and to investigate this further we initiated in vivo experiments using mice MRSA pneumonia models. Mice were treated with either LZD or vancomycin (VCM) immediately after intranasal administration of MRSA. Bacterial numbers and levels of inflammatory cytokines in the lungs were determined. Although the bacterial burden in the lungs was not apparently different between the two groups, LZD but not VCM treatment significantly reduced induction of inflammatory cytokines in the lungs (P < 0.05). To evaluate whether this anti-inflammatory response was due to suppression of virulence factor expression, filter-sterilized supernatants of MRSA incubated in broth overnight with sub-MICs of LZD were subcutaneously administered to mice. To clarify whether LZD possesses direct host-modulating activity, cytokine responses to the supernatants were examined in mice pretreated with LZD. Interestingly, MRSA solutions prepared in the presence of sub-MICs of LZD revealed significant suppression of interleukin 6 (IL-6) in a dose-dependent manner (P < 0.05), but pretreatment of mice with LZD revealed no changes in cytokines. These findings suggest that sub-MICs of LZD might suppress virulence factors of MRSA, which may be associated with a reduction in endogenous pyrogens. These data may explain at least in part early defervescence observed in LZD-treated individuals.

Bronchiectasis--diagnosis and treatment

BACKGROUND

Radiologically evident bronchiectasis is seen in 30% to 50% of patients with advanced chronic obstructive pulmonary disease (COPD). As COPD is now becoming more common around the world, bronchiectasis is as well.

METHODS

We review pertinent articles published before May 2011 that were retrieved by a selective PubMed search.

RESULTS

The principles of treatment of bronchiectasis in patients who do not have cystic fibrosis ("non-CF bronchiectasis") are derived from the treatment of other diseases: secretolytic and anti-infectious treatment are given as in cystic fibrosis, while anti-obstructive treatment is given as in COPD. The few randomized trials of treatment for non-CF bronchiectasis that have been completed to date do not permit the formulation of any evidence-based recommendations. Many potential treatments are now under evaluation. Hypertonic saline is often used because of its demonstrated benefit in CF, even though no benefit has yet been shown for non-CF bronchiectasis. Phase II trials of inhaled mannitol have yielded promising results, leading to phase III trials that are now underway. There may be a future role for inhaled antibiotics, particularly in patients colonized with Gram-negative pathogens. Inhaled tobramycin and colistin are well established in clinical practice, though not approved for non-CF bronchiectasis; clinical trials of aztreonam, ciprofloxacin, and gentamicin are ongoing. Macrolides seem to bring an additional benefit, though the studies that documented this involved only small numbers of patients. Long-term treatment with inhaled antibiotics and/or macrolides is indicated only if a benefit is seen within three months of the start of treatment (less sputum, no exacerbations).

CONCLUSION

A national registry of patients with bronchiectasis should be established to help us gain better knowledge of its prognostic factors and treatment options.

Physicochemical profile of macrolides and their comparison with small molecules

Macrolides are stereospecific macrolactones of high molecular weights. Herein, 600 mostly semisynthetic macrolides are compared with 50,000 small non-macrolide synthetic molecules in terms of measured physicochemical properties in order to assess the drug-likeness and developability chances of macrolides. The pre-selected set of diverse macrolides is comprised mostly of derivatives of clarithromycin and azithromycin cores. Lipophilicity (CHI logD), affinity for immobilized artificial membranes (CHI IAM), human serum albumin (HSA) and α(1)-acid glycoprotein (AGP) plasma protein bindings (PPB), DMSO precipitative solubility as well as artificial membrane permeability (AMP) have been determined by high-throughput screening methods. It has been found that macrolides and small molecules have similar lipophilicity profiles, though macrolides show weaker PPB and have better solubility than small discovery molecules. However, macrolides are poorly permeable and have high affinity for immobilized artificial membranes signifying their strong interaction with biological phospholipids. In order to retain the drug-like profile, the design of novel macrolide molecules should be focused on optimisation of macrolide cores, that is macrolactone moiety with sugars and other small substituents avoiding large substituents and flexible linkers such as in conjugate derivatives.

Azithromycin in periodontal treatment: more than an antibiotic

Azithromycin is a macrolide antibiotic used extensively in medicine for the treatment of a wide range of infections such as upper respiratory tract infections, middle ear infections, sexually transmitted infections and trachoma. It is also effective against the most common periodontopathogens. The versatility of the macrolides extends beyond their antibiotic properties as a result of their well-documented immune-modulating/anti-inflammatory effects. Macrolides, including azithromycin, are therefore used to treat diseases not associated with bacteria, such as severe asthma, chronic obstructive pulmonary diseases and, more recently, cystic fibrosis. Azithromycin is concentrated in neutrophils, macrophages and particularly fibroblasts; all of these cells are central players in the pathogenesis of most periodontal diseases. This paper reviews the diverse properties of azithromycin and the clinical periodontal studies of its effects in both the treatment of periodontitis and in resolving drug-related gingival overgrowth. Evidence exists to support the use of a single course of azithromycin in the treatment of advanced periodontal diseases. Azithromycin could have a triple role in the treatment and resolution of periodontal diseases: suppressing periodontopathogens, anti-inflammatory activity and healing through persistence at low levels in macrophages and fibroblasts in periodontal tissues, even after a single course of three tablets. If future periodontal research confirms these properties, it could become a valuable host-modulator in periodontal treatment.

Direct entry to erythronolides via a cyclic bis[allene]

The complexity and low tractability of antibiotic macrolides pose serious challenges to addressing the problem of resistance through semi- or total synthesis. Here we describe a new strategy involving the preparation of a complex yet tractable macrocycle and the transformation of this macrocycle into a range of erythronolide congeners. These compounds represent valuable sectors of erythromycinoid structure space and constitute intermediates with the potential to provide further purchase in this space. The routes are short. The erythronolides were prepared in three or fewer steps from the macrocycle, which was prepared in a longest linear sequence of 11 steps.

Long-term azithromycin therapy in patients with severe COPD and repeated exacerbations

Background

The aim of this study was to determine whether long-term intermittent azithromycin therapy reduces the frequency of exacerbation in severe chronic obstructive pulmonary disease (COPD).

Methods

We retrospectively investigated the clinical benefits of long-term azithromycin (500 mg orally three times per week) over 12 months in patients with severe COPD and a minimum of four acute exacerbations (AECOPD) per year or chronic bronchial colonization by Pseudomonas aeruginosa, comparing the number of AECOPD, hospitalizations due to respiratory disease, days of hospital stay, and bacterial infections during azithromycin treatment and in the year prior to this therapy.

Results

Twenty patients who completed the 12-month treatment period were analyzed. No clinically significant adverse events were observed during azithromycin treatment. Compared with baseline data, azithromycin therapy significantly reduced the number of AECOPD (2.8 ± 2.5 versus 6.8 ± 2.8, P < 0.001), hospitalizations (1.4 ± 1.5 versus 3.6 ± 1.4, P < 0.001), and cumulative annual days of hospital stay (25 ± 32.2 versus 43.7 ± 21.4, P = 0.01). The improvement was particularly significant in patients with exacerbations caused by common potentially pathogenic microorganisms, who had 70% fewer AECOPD and hospitalizations. Patients colonized by P. aeruginosa had reductions of 43% in AECOPD and 47% in hospitalizations.

Conclusion

Long-term azithromycin is well tolerated and associated with significant reductions in AECOPD, hospitalizations, and length of hospital stay in patients with severe COPD.

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.

Neomacrolides in the treatment of patients with severe asthma and/or bronchiectasis: a retrospective observational study

RATIONALE

Previous studies have demonstrated that long-term low-dose macrolides are efficacious in cystic fibrosis (CF) and diffuse panbronchiolitis, two chronic neutrophilic airway diseases.

AIMS

The aims of this study were to evaluate the efficacy and safety of low-dose neomacrolides as add-on therapy in patients with severe asthma and/or bronchiectasis and to identify predictors for therapeutic response.

METHODS

In a retrospective observational cohort study, we examined 131 adult, non-CF patients with severe asthma and/or bronchiectasis, receiving low-dose neomacrolides as add-on treatment. Pulmonary function tests and symptom scores were assessed at baseline and after 3 to 8 weeks of therapy.

RESULTS

After 3-8 weeks of treatment with low-dose neomacrolides, 108 patients were available for evaluation. In asthma patients (n = 47), pulmonary function tests and symptom scores improved significantly. Responders (≥7% forced expiratory volume in one second predicted [FEV(1)%] improvement) were older (55 vs. 47 years; p = 0.042) and had a longer duration of asthma (29 vs. 9 years; p = 0.052). In patients with bronchiectasis only (n = 61), symptom scores improved significantly. Responders (≥60% symptom score improvement) were older (61 vs. 53 years; p = 0.004), more frequently male (53% vs. 27%; p = 0.043), and there was a nonsignificant trend towards higher high-resolution CT (HRCT) score for bronchiectasis in responders (6.4 vs. 4.6; p = 0.053). In multivariate logistic regression analysis, age and male gender were independent predictors for improvement in this group.

CONCLUSION

The results of this retrospective study suggest that neomacrolides may be useful as an add-on therapy in patients with severe asthma and/or bronchiectasis. Older age may predict good response in patients with severe asthma, whereas older age, male gender and a higher HRCT score for bronchiectasis may predict therapeutic response in patients with bronchiectasis only. Prospective controlled trials of neomacrolides in patients with severe asthma are needed to confirm these observations.

Differing effects of azithromycin and doxycycline on cytokines in cells from Chlamydia trachomatis-infected women

Chlamydial infection of the lower genital tract usually spreads to the upper genital tract and is then responsible for more serious consequences, such as infertility, ectopic pregnancy, pelvic pain, and pelvic inflammatory disease. Genital infection with Chlamydia trachomatis and the resulting cytokine response largely determines the outcome of infection and disease. To date, studies showing comparative effects of azithromycin and doxycycline treatment for C. trachomatis infection in women with reproductive sequelae like infertility and their effect on immune molecules like cytokines are lacking. Hence, our objective was to study the effect of azithromycin and doxycycline in vitro on cytokines in cells from C. trachomatis-positive fertile and infertile women as well as their efficacy in C. trachomatis infection. Fertile and infertile women with primary and recurrent C. trachomatis infection attending the gynecology outpatient department of Safdarjung Hospital, New Delhi, India, were enrolled. Enzyme-linked immunosorbent assay and real-time reverse transcription-polymerase chain reaction was performed for evaluating cytokines in cells stimulated with chlamydial elementary bodies (EBs) in the presence and absence of antibiotics (azithromycin and doxycycline). C. trachomatis-infected women were also followed up to assess the efficacy of azithromycin and doxycycline. We observed inhibition of cytokines (interleukin [IL]-1beta (β), IL-6, IL-8, IL-10, and tumor necrosis factor-alpha) in the presence of azithromycin in EB-stimulated cells from both fertile and infertile women with primary and recurrent C. trachomatis infection. However, in presence of doxycycline, inhibition of cytokines (IL-1β and IL-6) was only observed in stimulated cells from fertile women with primary C. trachomatis infection. The clinical efficacy of azithromycin was also better than doxycycline in recurrent C. trachomatis infection in women with complications such as infertility. Overall, this study suggests that azithromycin treatment with broader immunomodulatory effects may be preferable to doxycycline for the treatment of recurrent C. trachomatis infection associated with infertility.

Evaluation of long-term clarithromycin treatment in adult Chinese Patients with chronic rhinosinusitis without nasal polyps

OBJECTIVE

To evaluate the efficacy of long-term clarithromycin (CAM) treatment in adult Chinese patients suffering from chronic rhinosinusitis without nasal polyps (CRSnNP).

METHODS

Thirty-three CRSnNP patients were enrolled and subjected to CAM treatment for 12 weeks (250 mg daily). The total nasal symptom scores (TNSS), nasal resistance and inflammatory mediators including interleukin (IL)-8 and myeloperoxidase (MPO) were evaluated at weeks 0 and 12. Quality of life (QoL) was assessed in all patients by using the Sinonasal Outcome Test 20 and Short Form 36 questionnaires.

RESULTS

CAM treatment significantly improved TNSS, nasal resistance and QoL, and it inhibited IL-8 and MPO production in CRSnNP patients (p < 0.05). CAM treatment was more effective for IL-8(high) CRSnNP patients than for IL-8(low) CRSnNP patients (p < 0.05).

CONCLUSION

Long-term, low-dose CAM treatment is effective and safe for the treatment of CRSnNP in Chinese patients.

Erythromycin prevents the pulmonary inflammation induced by exposure to cigarette smoke

The effect of erythromycin on the inflammation caused by exposure to cigarette smoke was investigated in this study. Mice were exposed either to cigarette smoke or to environmental air (control), and some mice exposed to cigarette smoke were treated with oral erythromycin (100 mg/kg/day for 8 days). Pulmonary inflammation was assessed by determining the cellular content of bronchoalveolar lavage (BAL) fluid. The messenger RNA (mRNA) levels of various mediators, including keratinocyte-derived chemokine (KC), macrophage inflammatory protein (MIP)-2, surfactant protein (SP)-D, granulocyte macrophage colony-stimulating factor (GM-CSF), tumor necrosis factor (TNF)-α, interleukin (IL)-6 in lung tissue were determined using quantitative reverse transcription polymerase chain reaction (qRT-PCR) assays. The exposure to cigarette smoke increased significantly the numbers of neutrophils (P = 0.029), macrophages (P = 0.029), and lymphocytes (P = 0.029) recovered in BAL fluid. Moreover, mRNA levels of KC (P = 0.029), MIP-2 (P = 0.029), SP-D (P = 0.029), and GM-CSF (P = 0.057) in the lung tissue were higher in mice exposed to cigarette smoke than in mice exposed to environmental air. In the erythromycin-treated mice that were exposed also to cigarette smoke, both neutrophil and lymphocyte counts were significantly lower in the BAL fluid than those in the vehicle-treated mice (P = 0.029). Erythromycin-treated mice exposed to cigarette smoke showed a trend of lower mRNA levels of KC and TNF-α in the lung tissue than those in the vehicle-treated mice, although the statistical significance was not achieved (P = 0.057). Our data demonstrated that erythromycin prevented lung inflammation induced by cigarette smoke, in parallel to the reduced mRNA levels of KC and TNF-α.

Clarithromycin inhibits interleukin-13-induced goblet cell hyperplasia in human airway cells

IL-13 is a T-helper class 2 cytokine that induces goblet cell hyperplasia and mucus production in airway epithelial cells. Because macrolide antibiotics are known to have immunomodulatory and mucoregulatory properties, the aim of this study was to examine the effect of clarithromycin on IL-13-induced goblet cell hyperplasia and mucin hypersecretion in normal human bronchial epithelial (NHBE) cells. NHBE cells were cultured to differentiation at an air-liquid interface with IL-13 plus clarithromycin or vehicle. Histochemical analysis was performed using H&E staining, periodic acid-Schiff (PAS) staining, and MUC5AC immunostaining. MUC5AC synthesis was assayed using RT-PCR and ELISA. Western blotting was used to evaluate signaling pathways. IL-13 significantly increased the number of PAS-positive, MUC5AC-positive goblet cells, and this was significantly attenuated by clarithromycin at concentrations greater than 8 μg/ml (P < 0.01). Clarithromycin also dose-dependently decreased MUC5AC mRNA expression induced by IL-13 (P < 0.001), and, at 24 μg/ml, clarithromycin significantly attenuated the amount of MUC5AC protein in cell supernatants (P < 0.01). Western blotting showed that clarithromycin affected IL-13 receptor janus kinase signal transducers, activators of transcription6 (STAT6), and epidermal growth factor receptor mitogen-activated protein kinase signaling and that inhibition of these pathways by clarithromycin decreased goblet cell hyperplasia via nuclear factor-κB inactivation. We conclude that clarithromycin inhibits goblet cell hyperplasia and may directly regulate mucus secretion by IL-13 in NHBE cells.

Effects of scutellarin on MUC5AC mucin production induced by human neutrophil elastase or interleukin 13 on airway epithelial cells

Scutellarin is a flavonoid extracted from a traditional Chinese herb, Erigeron breviscapus. The present study investigated the effect of scutellarin on MUC5AC mucin production and the possible mechanism. Human bronchial epithelial 16 (HBE16) cells were pretreated with scutellarin for 60 min, and then exposed to human neutrophil elastase (HNE) or interleukin (IL)-13 for 12 hr. RT-PCR and ELISA were performed to measure the amount of MUC5AC mucin production. The results showed that scutellarin inhibited MUC5AC expression both in mRNA and protein level induced by HNE in a concentration-dependent manner. However, scutellarin failed to inhibit MUC5AC mucin production induced by IL-13. To investigate the intracellular mechanisms associated with the effect of scutellarin on MUC5AC mucin production, western blotting was carried out to examine the phosphorylation of protein kinase C (PKC), signal transducer and activator of transcription 6 (STAT6) and extracellular signal-regulated kinase 1/2 (ERK1/2). The phosphorylation of PKC and ERK1/2 was attenuated after treatment with scutellarin, whereas STAT6 was not significantly affected. Therefore, it is suggested that scutellarin down-regulates MUC5AC mucin production on HBE16 cells via ERK-dependent and PKC-dependent pathways.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Anti-inflammatory effects of tilmicosin in a noninfectious mouse model of allergic asthma

Tilmicosin, a semi-synthetic tylosin-derived macrolide antibiotic commonly used by veterinarians, has been shown to possess anti-inflammatory activity. However, possible use in asthma treatment has not yet been studied. In this study, we investigated the anti-inflammatory properties of tilmicosin using a murine asthma model. BALB/c mice were sensitized and challenged by intraperitoneal (i.p.) or nasal administration of ovalbumin. Tilmicosin (10 and 20 mg/kg) treatment resulted in a marked reduction in the presence of several types of immune cells and cytokines in the bronchoalveolar lavage fluids of mice. Levels of ovalbumin-specific Immunoglobulin E (IgE) were significantly decreased following treatment with tilmicosin (10 and 20 mg/kg). Histological studies using H&E (haematoxylin and eosin) and AB-PAS (alcian blue-periodic acid-Schiff) staining demonstrated that tilmicosin substantially inhibited both ovalbumin-induced inflammatory cells in lung tissues and goblet cell hyperplasia in the airway. These findings provided new insight into the immunopharmacological role of tilmicosin in terms of its effects in a murine model of asthma.

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

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

Unexpected applications of secondary metabolites

Secondary metabolites have been found to have interesting applications over and above their well-known medical uses, e.g., as antimicrobials, etc. These alternative applications include antitumor, cholesterol-lowering, immunosuppressant, antiprotozoal, antihelminth, antiviral and anti-ageing activities. Polyene antibiotics, such as amphotericin B, are of use as antiprion agents, antitumor drugs and against leishmaniasis. Other microbial natural products that show antibiotic activity are used against cancer e.g., doxorubicin, neomycin, β-lactams, bleomycin and rapamycin. Macrolide antibiotics, such as erythromycin, clarithromycin and azithromycin, improve pulmonary function in patients suffering from panbioncholitis. Pigments like prodigiosin and shikonin have antitumor activity, while violacein has anti-ulcer and antitumor activity and also acts as an antiprotozoal agent. Statins, in addition to lowering cholesterol and LDL levels, also decrease elevated C-reactive protein (CRP) levels independent of their cholesterol effects. Immunosuppressants have many alternative effects: (i) Cyclosporin is proving useful in treatment of inflammatory disease such as asthma and muscular dystrophy. (ii) Rapamycin is extremely useful in preventing restenosis of stents grafted in balloon angioplasty. (iii) Tacrolimus and ascomycin help in treating inflammatory skin disease such as allergic contact dermatitis and psoriasis. Artemisinin, an antimalarial agent, is also showing antitumor activity. Other natural products, including those from plants (betulinic acid and shikonin), animals (bryostatins) and microbes (squalestatin and sophorolipids) have a multiplicity of potentially useful actions. Unexpected functions of known secondary metabolites are continuously being unraveled, and are fulfilling some of the needs of present day medicine and show great promise for the future.

Regulatory properties of polysaccharopeptide derived from Coriolus versicolor and its combined effect with ciclosporin on the homeostasis of human lymphocytes

OBJECTIVES

Lymphocyte homoeostasis is essential in inflammatory and autoimmune diseases. In search of natural fungal metabolites with effects on lymphocyte homoeostasis, we recently reported that polysaccharopeptide (PSP) from Coriolus versicolor exhibited ciclosporin-like activity in controlling aberrant lymphocyte activation. This object of this study was to investigate its effect on lymphocyte homoeostasis. This was done by investigating the mechanistic actions of PSP in relation to ciclosporin by performing cell cycle and cell death analysis of human lymphocytes in vitro.

METHODS

We investigated the effect of PSP in the presence and absence of ciclosporin on cell proliferation, cell cycle, cell death, immunophenotype and cell cycle regulatory proteins in human lymphocytes.

KEY FINDINGS

The data showed that PSP exhibited homoeostatic activity by promoting and inhibiting the proliferation of resting and phytohaemagglutinin (PHA)-stimulated lymphocytes, respectively. PHA-stimulated lymphocytes exhibited G0/G1 cell cycle arrest that was accompanied by a reduction of cyclin E expression with PSP treatment. Both PSP and ciclosporin blocked the reduction of the CD4/CD8 ratio in stimulated lymphocytes. PSP did not induce cell death in human lymphocytes, but the suppression of the Fasreceptor suggested a protective role of PSP against extrinsic cell death signals. These homoeostatic effects were more potent with combined PSP and ciclosporin treatment than with either fungal metabolite alone.

CONCLUSIONS

Collectively, the results reveal certain novel effects of PSP in lymphocyte homoeostasis and suggest potential as a specific immunomodulatory adjuvant for clinical applications in the treatment of autoimmune diseases.

Inverse relation between vitamin D and serum total immunoglobulin G in the Scandinavian Cystic Fibrosis Nutritional Study

BACKGROUND/OBJECTIVES

The hallmark of cystic fibrosis (CF) is chronic lung inflammation. The severity of lung disease is closely correlated with immunoglobulin G (IgG) levels. Beyond its contribution to the bone health, the importance of vitamin D has not been fully recognized owing to the lack of human studies providing evidence of its benefit. In the context of the recently described immunomodulatory functions of vitamin D, we aimed to assess the relationship between vitamin D and IgG levels.

SUBJECTS/METHODS

Eight hundred and ninety-six CF patients were included (0.53-65.9 years) from seven centers in Denmark, Norway and Sweden. Serum 25-hydroxyvitamin D (25OHD) and total IgG were measured, spirometry was carried out and vitamin D intake data were gathered using a 7-day dietary food record. Multiple linear regression analyses were performed for IgG and forced expiratory volume in 1λs (FEV1) as dependent variables, and serum 25OHD, daily food and supplemented vitamin D sources of intake as independent variables. The model was controlled for age, gender, genotype, CF-related diabetes, season, infection/colonization status, long-term oral corticosteroid treatment, long-term treatment with macrolide antibiotics, pancreatic insufficient phenotype and body mass index z-score.

RESULTS

Serum total IgG levels were negatively associated with serum 25OHD (adjusted R (2) = 0.376; beta = -0.02; P<0.001), supplemented vitamin D intake per kg bodyweight (adjusted R (2) = 0.375; beta = -0.82; P < 0.001) and total vitamin D intake per kg bodyweight (adjusted R (2) = 0.398; beta = -0.60; P = 0.002). Serum 25OHD was positively associated with FEV1 (adjusted R (2) = 0.308; beta = 0.0007; P = 0.025).

CONCLUSIONS

Increasing vitamin D intake may positively modulate inflammation in CF. This study supports the proposed role of vitamin D in the immune system during infection and substantiates prospective studies.

Advances in the prevention, management, and treatment of community-acquired pneumonia

Despite the availability of powerful antibiotics, community-acquired pneumonia (CAP) remains one of the leading reasons for morbidity and mortality worldwide, and despite the availability of powerful antibiotics, there has been only little improvement in case fatality rates for many years. Consequently, it cannot be expected that novel antibiotics will substantially improve outcomes in CAP. Therefore, this review focuses on novel approaches that may reduce CAP-related mortality: the impact of immunomodulation by macrolides and fluoroquinolones and the prevention of CAP by pneumococcal vaccines.

Macrolides and community-acquired pneumonia: is quorum sensing the key?

Combination therapy with two antimicrobial agents is superior to monotherapy in severe community-acquired pneumonia, and recent data suggest that addition of a macrolide as the second antibiotic might be superior to other combinations. This observation requires confirmation in a randomised control trial, but this group of antibiotics have pleiotropic effects that extend beyond bacterial killing. Macrolides inhibit bacterial cell-to-cell communication or quorum sensing, which not only might be an important mechanism of action for these drugs in severe infections but may also provide a novel target for the development of new anti-infective drugs.

Challenges of treating asthma in people who smoke

Cigarette smoking is common in asthma and is associated with poor symptom control and a reduced therapeutic response to inhaled and oral corticosteroids as compared with nonsmokers with asthma. This review examines the range of adverse health effects of smoking in asthma, the inflammatory mechanisms that may influence the efficacy of current drugs and discusses potential future therapeutic directions.

Prophylactic antibiotic therapy in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) represents a huge epidemiological burden and is associated with a high incidence of morbidity and mortality. The disease is characterized by chronic inflammation and bacterial colonization. Chronic bacterial colonization leads to chronic inflammation and epithelial damage that in turn may increase bacterial colonization and predispose to acute bacterial infection. Acute exacerbations are a major cause of hospitalization and lead to a deterioration in pulmonary function. Antibiotic treatment of acute bacterial exacerbations is a cornerstone of medical treatment. Conversely, the role of antibiotic prophylaxis in COPD in the stable state is controversial. From a theoretical point of view, antibiotic prophylaxis is intriguing as it could break the vicious circle between chronic bacterial colonization, inflammation and epithelial damage; however, evidence is scarce. This paper reviews the literature and focuses on the most recent data shedding light on this fascinating dilemma.

[Asthma and Mycoplasma pneumoniae]

INTRODUCTION

A growing body of basic and clinical science implicates Mycoplasma pneumonia in asthma, but its exact contribution to asthma development, exacerbation and persistence is as yet unclear.

STATE OF THE ART

M. pneumoniae infection, with the induction of bronchial hyperresponsiveness, seems to be a precipitating factor for asthma development in predisposed subjects. M. pneumoniae has been seen both in acute exacerbation (18-20%) and in chronically infected adults with stable asthma, where it may be enhancing chronic airway inflammation.

PERSPECTIVES

If M. pneumoniae plays a role in the development or progression of asthma, its eradication might influence the clinical course of the disease and improve symptoms. Macrolide treatment, with antimicrobial and anti-inflammatory properties, could have a place in the management of asthma, especially steroid-dependent asthma.

CONCLUSIONS

M. pneumoniae infection seems to be important in asthma pathogenesis and the clinical course of the disease. Difficulty in detecting the pathogen complicates investigations. Ongoing research will further determine the place of macrolide antibiotics in asthma management.

Anti-inflammatory effects of macrolides: applications in chronic rhinosinusitis

The anti-inflammatory effects of macrolides are significant. The clinical impact on diffuse panbronchiolitis (DPB) has improved 10-year survival from 12% to more than 90% for these patients. The immunomodulatory activity of macrolides has been a source of mechanistic research as well as clinical research in non-DPB inflammatory airway disease. Suppression of neutrophilic inflammation of the airways has been demonstrated as the most robust immunomodulatory response from 14- and 15-membered ring macrolides. The inhibition of transcription factors, mainly nuclear factor-kB and activator protein 1, from alterations in intracellular cell signaling drives this mechanism. The suppression of interleukin-8 to a range of endogenous and exogenous challenges characterizes the alterations to cytokine production. The inflammatory mechanisms of chronic rhinosinusitis (CRS) have been a major non-DPB focus. Macrolides have been trialed in more than 14 prospective trials and are the focus of numerous research projects. Evidence for a strong clinical effect in CRS is mounting, but results may be tempered by researchers' inability to characterize the disease process. Eosinophilic dominated CRS is unlikely to respond, based on current research understanding and data from clinical trials. This article discusses the current concepts of macrolides and their application in the management of CRS.

Chronic cough and obstructive sleep apnea in a community-based pulmonary practice

BACKGROUND

Recent reports suggest an association between unexplained chronic cough and obstructive sleep apnea (OSA). Current guidelines provide an empiric integrative approach to the management of chronic cough, particularly for etiologies of gastroesophageal reflux (GERD), upper airway cough syndrome (UACS) and cough variant asthma (CVA) but do not provide any recommendations regarding testing for OSA. This study was done to evaluate the prevalence of OSA in patients referred for chronic cough and examine the impact of treating OSA in resolution of chronic cough.

METHODS

A retrospective review of chronic cough patients seen over a four-year period in a community-based pulmonary practice was done. Patients with abnormal chest radiographs, abnormal pulmonary function tests, history of known parenchymal lung disease, and inadequate followup were excluded. Clinical data, treatments provided and degree of resolution of cough was evaluated based on chart review. Specifically, diagnostic testing for OSA and impact of management of OSA on chronic cough was assessed.

RESULTS

75 patients with isolated chronic cough were identified. 44/75 had single etiologies for cough (GERD 37%, UACS 12%, CVA 8%). 31/75 had multiple etiologies for their chronic cough (GERD-UACS 31%, GERD-CVA 5%, UACS-CVA 3%, GERD-UACS-CVA 3%). 31% patients underwent further diagnostic testing to evaluate for UACS, GERD and CVA. Specific testing for OSA was carried out in 38/75 (51%) patients and 33/75 (44%) were found to have obstructive sleep apnea. 93% of the patients that had interventions to optimize their sleep-disordered breathing had improvement in their cough.

CONCLUSIONS

OSA is a common finding in patients with chronic cough, even when another cause of cough has been identified. CPAP therapy in combination with other specific therapy for cough leads to a reduction in cough severity. Sleep apnea evaluation and therapy needs to considered early during the management of chronic cough and as a part of the diagnostic workup for chronic cough.

New treatment options for bronchiectasis

Therapies shown to be effective in cystic fibrosis are often provided to patients with bronchiectasis, without definitive evidence of benefit. In recent years, there has been increased interest in validating and developing new therapies for patients with noncystic fibrosis bronchiectasis. While inhaled tobramycin improves microbiologic parameters, improvements in outcomes have been more difficult to demonstrate, in part due to the occurrence of bronchospasm in a significant minority of treated patients. Outcome data from studies of inhaled aztreonam and ciprofloxacin have not yet been reported, although the microbiologic data appear to be promising. Preliminary data regarding inhaled hyperosmolar agents such as hypertonic saline and mannitol are also promising, but these therapies cannot yet be recommended for routine therapy of patients with bronchiectasis. Macrolide antibiotics have anti-inflammatory properties in patients with chronic suppurative lung disease, through a variety of mechanisms. They have been proven to be beneficial in diffuse panbronchiolitis and are commonly being used in patients with bronchiectasis. Many small studies support their use in this population, although several had methodologic flaws. Thus, although chronic low-dose macrolide therapy is often used in these patients, more conclusive evidence is awaited.

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?

Boost of mucosal secretory immunoglobulin A response by clarithromycin in paediatric influenza

BACKGROUND AND OBJECTIVE

The antiviral neuraminidase inhibitor oseltamivir (OSV) is used to treat influenza. The macrolide clarithromycin (CAM) is used to treat bacterial infections and has anti-inflammatory and immunomodulatory activities. This retrospective study investigated the immunomodulatory effects of CAM in children presenting with influenza A.

METHODS

The study recruited 40 children with acute influenza, and grouped them according to the treatment received: 5-day treatment with OSV (n = 14), CAM (n = 8), OSV + CAM (n = 12) and untreated (n = 6). The before and after treatment comparisons were made of the level of secretory IgA (sIgA) against influenza A virus (H3N2) and (H1N1), total sIgA, viral RNA copy numbers in nasopharyngeal aspirates and disease symptoms.

RESULTS

Infection induced anti-viral mucosal sIgA in the nasopharyngeal aspirates of most patients of all treatment groups. Particularly prominent increases in the levels were found in the CAM and OSV + CAM groups. Low induction of anti-viral sIgA was observed in the OSV group, but the addition of CAM to OSV augmented sIgA production and restored local mucosal sIgA levels. The frequency of residual cough in the OSV + CAM group was significantly lower than in the other groups including the group treated with OSV.

CONCLUSIONS

CAM boosted the nasopharyngeal mucosal immune response in children presenting with influenza A, even in those treated with OSV who had low production of mucosal anti-viral sIgA, and alleviated the symptoms of influenza.

Polysaccharopeptide mimics ciclosporin-mediated Th1/Th2 cytokine balance for suppression of activated human T cell proliferation by MAPKp38 and STAT5 pathways

The activation of T helper (Th) cell subsets plays an important role in the human immune system. Uncontrolled Th1 and Th2 responses lead to autoimmune and inflammatory diseases, respectively. The identification of agents that modulate the Th1/Th2 cytokines is therefore essential for controlling these diseases. We recently reported that polysaccharopeptide (PSP) from Coriolus versicolor exhibited ciclosporin-like activities to control aberrant T lymphocyte activation. Here, we compared the properties of PSP with ciclosporin on cell proliferation, CD25+ expression, secretion of Th1/Th2 cytokines and activation of mitogen-activated protein kinase (MAPK)p38 and signal transducers and activators of transcription 5 (STAT5) on T cells. The data show that PSP alone suppresses the proliferation of activated T cells. PSP exhibited similar and additive inhibitory effects to ciclosporin to suppress activated T cell proliferation, Th1 cytokines and reduce CD3+/CD25+ cell expression, but not Th2 cytokine expression, which helps the cytokine balance shift towards Th2 dominance. These suppressive actions of PSP involved the MAPKp38 and STAT5 pathways. These findings refine our understanding of the effects of PSP on T lymphocytes and its adjuvant properties with the immunosuppressant ciclosporin for possible control of autoimmune diseases.

Primary ciliary dyskinesia that responded to long-term, low-dose clarithromycin

A 46-year-old man was referred to our hospital with hemoptysis. He had been diagnosed with chronic sinusitis since childhood, but had received no treatment. Chest CT showed a diffuse centrilobular granular shadow and thickened bronchial walls. Otitis media and decreased spermatic motor ability were identified. In addition, electron microscopy of a biopsy specimen of the nasal mucosa showed a deficiency of inner dynein. Based on these clinical findings, primary ciliary dyskinesia (PCD) was diagnosed and successfully treated with long-term, low-dose clarithromycin. Although the effects of macrolide therapy remain controversial, long-term treatment with low-dose clarithromycin might confer clinical benefits upon patients with PCD.

Anti-inflammatory drug therapy in asthma

Asthma is a disease with chronic inflammation of the airways and and-inflammatory treatment is a logical treatment. Inhaled corticosteroids [ICS] remain the cornerstone of anti-inflammatory therapy in recent international guidelines. Asthma cannot be cured by any medication: if the drug is discontinued, the disease manifestations return. This has been proven at all ages. In preschool children the diagnosis of asthma is difficult to establish. In this heterogeneous group ICS or leukotriene receptor antagonists [LTRA] are just as effective as placebo; in the future it will hopefully be possible to describe characteristics of responders. LTRA are an alternative in mild asthma, especially when mono-triggered viral related wheeze is present. Theophylline is effective and also has bronchodilatory properties, which need to be balanced against the relatively frequent side effects. The working mechanisms of anti-inflammatory asthma medications including ICS, LTRA, cromones, macrolides and theophylline are described.

Azithromycin and clarithromycin inhibit lipopolysaccharide-induced murine pulmonary neutrophilia mainly through effects on macrophage-derived granulocyte-macrophage colony-stimulating factor and interleukin-1beta

Macrolide antibiotics possess immunomodulatory/anti-inflammatory properties. These properties are considered fundamental for the efficacy of macrolide antibiotics in the treatment of chronic inflammatory diseases like diffuse panbronchiolitis and cystic fibrosis. However, the molecular mechanisms and cellular targets of anti-inflammatory/immunomodulatory macrolide activity are still not fully understood. To describe anti-inflammatory effects of macrolides in more detail and to identify potential biomarkers of their activity, we have investigated the influence of azithromycin and clarithromycin on the inflammatory cascade leading to neutrophil infiltration into lungs after intranasal lipopolysaccharide challenge in mice. Azithromycin and clarithromycin pretreatment reduced total cell and neutrophil numbers in bronchoalveolar lavage fluid and myeloperoxidase concentration in lung tissue. In addition, concentrations of several inflammatory mediators, including CCL2, granulocyte-macrophage colony stimulating factor (GM-CSF), interleukin-1beta (IL-1beta), tumor necrosis factor alpha, and sE-selectin in lung homogenates were decreased after macrolide treatment. Inhibition of cytokine production observed in vivo was also corroborated in vitro in lipopolysaccharide-stimulated monocytes/macrophages, but not in an epithelial cell line. In summary, results presented in this article confirm that macrolides can suppress neutrophil-dominated pulmonary inflammation and suggest that the effect is mediated through inhibition of GM-CSF and IL-1beta production by alveolar macrophages. Besides GM-CSF and IL-1beta, CCL2 and sE-selectin are also identified as potential biomarkers of macrolide anti-inflammatory activity in the lungs.