Diffuse Panbronchiolitis

Impact of primary ciliary dyskinesia: Beyond sinobronchial syndrome in Japan

Primary ciliary dyskinesia (PCD) is a rare genetic disorder characterized by impaired motile cilia function, particularly in the upper and lower airways. To date, more than 50 causative genes related to the movement, development, and maintenance of cilia have been identified. PCD mostly follows an autosomal recessive inheritance pattern, in which PCD symptoms manifest only in the presence of pathogenic variants in both alleles. Several genes causing PCD have been recently identified that neither lead to situs inversus nor cause definitive abnormalities in ciliary ultrastructure. Importantly, the distribution of disease-causing genes and pathogenic variants varies depending on ethnicity. In Japan, homozygosity for a ∼27.7-kb deletion of DRC1 is estimated to be the most common cause of PCD, presumably as a founder mutation. The clinical picture of PCD is similar to that of sinobronchial syndrome, thus making its differentiation from diffuse panbronchiolitis and other related disorders difficult. Given the diagnostic challenges, many cases remain undiagnosed or misdiagnosed, particularly in adults. While no fundamental cure is currently available, lifelong medical subsidies are provided in Japan, and proper respiratory management, along with continued prevention and treatment of infections, is believed to mitigate the decline in respiratory function. Timely action will be necessary when specific treatments for PCD become available in the future. This narrative review focuses on variations in the disease status of PCD in a non-Western country.

Macrolides Decrease the Proinflammatory Activity of Macrolide-Resistant Streptococcus pneumoniae

Over the past 2 decades, the prevalence of macrolide-resistant Streptococcus pneumoniae (MRSP) has increased considerably, due to widespread macrolide use. Although macrolide usage has been proposed to be associated with treatment failure in patients with pneumococcal diseases, macrolides may be clinically effective for treating these diseases, regardless of the susceptibility of the causative pneumococci to macrolides. As we previously demonstrated that macrolides downregulate the transcription of various genes in MRSP, including the gene encoding the pore-forming toxin pneumolysin, we hypothesized that macrolides affect the proinflammatory activity of MRSP. Using HEK-Blue cell lines, we found that the supernatants from macrolide-treated MRSP cultures induced decreased NF-κB activation in cells expressing Toll-like receptor 2 and nucleotide-binding oligomerization domain 2 compared to the supernatants from untreated MRSP cells, suggesting that macrolides inhibit the release of these ligands from MRSP. Real-time PCR analysis revealed that macrolides significantly downregulated the transcription of various genes encoding peptidoglycan synthesis-, lipoteichoic acid synthesis-, and lipoprotein synthesis-related molecules in MRSP cells. The silkworm larva plasma assay demonstrated that the peptidoglycan concentrations in the supernatants from macrolide-treated MRSP cultures were significantly lower than those from untreated MRSP cultures. Triton X-114 phase separation revealed that lipoprotein expression decreased in macrolide-treated MRSP cells compared to the lipoprotein expression in untreated MRSP cells. Consequently, macrolides may decrease the expression of bacterial ligands of innate immune receptors, resulting in the decreased proinflammatory activity of MRSP. IMPORTANCE To date, the clinical efficacy of macrolides in pneumococcal disease is assumed to be linked to their ability to inhibit the release of pneumolysin. However, our previous study demonstrated that oral administration of macrolides to mice intratracheally infected with macrolide-resistant Streptococcus pneumoniae resulted in decreased levels of pneumolysin and proinflammatory cytokines in bronchoalveolar lavage fluid samples compared to the levels in samples from untreated infected control mice, without affecting the bacterial load in the fluid. This finding suggests that additional mechanisms by which macrolides negatively regulate proinflammatory cytokine production may be involved in their efficacy in vivo. Furthermore, in this study, we demonstrated that macrolides downregulated the transcription of various proinflammatory-component-related genes in S. pneumoniae, which provides an additional explanation for the clinical benefits of macrolides.

Natural products: A lead for drug discovery and development

Natural products are used since ancient times in folklore for the treatment of various ailments. Plant-derived products have been recognized for many years as a source of therapeutic agents and structural diversity. A literature survey has been carried out to determine the utility of natural molecules and their modified analogs or derivatives as pharmacological active entities. This review presents a study on the importance of natural products in terms of drug discovery and development. It describes how the natural components can be utilized after small modifications in new perspectives. Various new modifications in structure offer a unique opportunity to establish a new molecular entity with better pharmacological potential. It was concluded that in this current era, new attempts are taken to utilize the compounds derived from natural sources as novel drug candidates, with a focus to find and discover new effective molecules that were referred to as "new entities of natural product drug discovery."

Isolation of Mycobacterium talmoniae from a patient with diffuse panbronchiolitis: a case report

BACKGROUND

Mycobacterium (M) talmoniae isolated from a patient with cystic fibrosis was first described in 2017, and cases of M. talmoniae remain exceedingly rare.

CASE PRESENTATION

A 51-year-old woman had respiratory symptoms for 10 years. Diffuse panbronchiolitis (DPB) was detected at the first visit at our hospital. A cavity lesion in the apex of the left lung was found, and sputum and bronchoalveolar lavage fluid were acid-fast bacillus (AFB) smear- and culture-positive besides Pseudomonas aeruginosa. M. talmoniae was finally identified, and the standard combination therapy for non-tuberculous mycobacteria (NTM) was administered for 2 y referring to the drug-susceptibility test. Thereafter, the AFB culture was negative, the wall thickness of the lung cavity was ameliorated, and oxygen saturation improved.

CONCLUSIONS

We encountered a rare case of M. talmoniae with DPB, for which standard combination therapy was effective. M. talmoniae may be considered a potential pathogen of lung disease, especially in patients with bronchiectatic lesions.

Multitarget Approaches against Multiresistant Superbugs

Despite efforts to develop new antibiotics, antibacterial resistance still develops too fast for drug discovery to keep pace. Often, resistance against a new drug develops even before it reaches the market. This continued resistance crisis has demonstrated that resistance to antibiotics with single protein targets develops too rapidly to be sustainable. Most successful long-established antibiotics target more than one molecule or possess targets, which are encoded by multiple genes. This realization has motivated a change in antibiotic development toward drug candidates with multiple targets. Some mechanisms of action presuppose multiple targets or at least multiple effects, such as targeting the cytoplasmic membrane or the carrier molecule bactoprenol phosphate and are therefore particularly promising. Moreover, combination therapy approaches are being developed to break antibiotic resistance or to sensitize bacteria to antibiotic action. In this Review, we provide an overview of antibacterial multitarget approaches and the mechanisms behind them.

Primary ciliary dyskinesia caused by a large homozygous deletion including exons 1-4 of DRC1 in Japanese patients with recurrent sinopulmonary infection

BACKGROUND

Diffuse panbronchiolitis (DPB) is a sinopulmonary disease mainly affecting Asian populations. Primary ciliary dyskinesia (PCD) is a genetically heterogeneous disorder impairing ciliary structure and function. These two disorders are not easily distinguished by clinical signs and symptoms.

METHODS

In 105 Japanese patients with recurrent sinopulmonary infection, initially diagnosed with DPB, and 37 patients with recurrent airway infection diagnosed in adulthood, the deletion allele of DRC1 or CCDC164, recently recognized as a pathogenic PCD gene variant, was searched using a multiplexed PCR-based method, and the deletion breakpoints and other variants around the gene were determined by Sanger sequencing and targeted resequencing.

RESULTS

A large homozygous deletion in DRC1 was identified in three of the 142 patients. Furthermore, heterozygous carriers of the deletion with the same breakpoint were found with the allele frequency of 0.002 in the healthy Japanese population, indicating that this loss-of-function variant may be acting as a common mutation causing PCD in Japanese.

CONCLUSION

PCD caused by the DRC1 defect is not readily identified by either high-speed video-microscopy or ciliary ultrastructure analysis, posing significant difficulties in reaching a correct diagnosis without the aid of genetic tests. Careful investigation of the causes of sinopulmonary diseases is warranted in Asian populations.

Thymic neoplasms patients complicated with bronchiectasis: Case series in a Chinese hospital and literature review

Background

Bronchiectasis is a rare complication in patients with thymic neoplasm. The aim of this study was to investigate the clinical and radiological manifestations, laboratory tests, pathologic features, and outcome of treatment of bronchiectasis in patients with thymic neoplasm.

Methods

From January 2000 to January 2018, 20 patients with a diagnosis of thymic neoplasm and bronchiectasis were hospitalized at the Peking Union Medical College Hospital. Clinical data was retrospectively analyzed.

Results

The prevalence of bronchiectasis in thymic neoplasms in our cohort was 1.56% (20/1279). Eighteen patients were diagnosed with thymoma, while two patients were diagnosed with thymic carcinoid. The duration from diagnosis of thymic neoplasm to bronchiectasis varied. Distributions of bronchiectasis were bilateral in 17 patients and unilateral in three patients. Four patients were previously diagnosed with diffuse panbronchiolitis and another two were suspected with diffuse panbronchiolitis. Twelve patients had various parathymic syndromes, including Good syndrome, myasthenia gravis, and aplastic anemia. Thymectomy was performed in all of these patients. Macrolide antibiotics were administered to 10 patients, and the symptoms improved in 8.

Conclusion

Bronchiectasis is a complication in thymic neoplasms, although prevalence is low. There may be multifactorial etiologies for bronchiectasis in patients with thymic neoplasms. Comprehensive treatment should be carried out to ensure optimal outcomes.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSION

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

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Interference of bacterial cell-to-cell communication: a new concept of antimicrobial chemotherapy breaks antibiotic resistance

Bacteria use a cell-to-cell communication activity termed "quorum sensing" to coordinate group behaviors in a cell density dependent manner. Quorum sensing influences the expression profile of diverse genes, including antibiotic tolerance and virulence determinants, via specific chemical compounds called "autoinducers". During quorum sensing, Gram-negative bacteria typically use an acylated homoserine lactone (AHL) called autoinducer 1. Since the first discovery of quorum sensing in a marine bacterium, it has been recognized that more than 100 species possess this mechanism of cell-to-cell communication. In addition to being of interest from a biological standpoint, quorum sensing is a potential target for antimicrobial chemotherapy. This unique concept of antimicrobial control relies on reducing the burden of virulence rather than killing the bacteria. It is believed that this approach will not only suppress the development of antibiotic resistance, but will also improve the treatment of refractory infections triggered by multi-drug resistant pathogens. In this paper, we review and track recent progress in studies on AHL inhibitors/modulators from a biological standpoint. It has been discovered that both natural and synthetic compounds can disrupt quorum sensing by a variety of means, such as jamming signal transduction, inhibition of signal production and break-down and trapping of signal compounds. We also focus on the regulatory elements that attenuate quorum sensing activities and discuss their unique properties. Understanding the biological roles of regulatory elements might be useful in developing inhibitor applications and understanding how quorum sensing is controlled.

Recycling of peptidyl-tRNAs by peptidyl-tRNA hydrolase counteracts azithromycin-mediated effects on Pseudomonas aeruginosa

Acute and chronic infections caused by the opportunistic pathogen Pseudomonas aeruginosa pose a serious threat to human health worldwide, and its increasing resistance to antibiotics requires alternative treatments that are more effective than available strategies. Clinical studies have clearly demonstrated that cystic fibrosis (CF) patients with chronic P. aeruginosa infections benefit from long-term low-dose azithromycin (AZM) treatment. Immunomodulating activity, the impact of AZM on the expression of quorum-sensing-dependent virulence factors, type three secretion, and motility in P. aeruginosa seem to contribute to the therapeutic response. However, to date, the molecular mechanisms underlying these AZM effects have remained elusive. Our data indicate that the AZM-mediated phenotype is caused by a depletion of the intracellular pools of tRNAs available for protein synthesis. Overexpression of the P. aeruginosa peptidyl-tRNA hydrolase, which recycles the tRNA from peptidyl-tRNA drop-off during translation, counteracted the effects of AZM on stationary-phase cell killing, cytotoxicity, and the production of rhamnolipids and partially restored swarming motility. Intriguingly, the exchange of a rare for a frequent codon in rhlR also explicitly diminished the AZM-mediated decreased production of rhamnolipids. These results indicate that depletion of the tRNA pools by AZM seems to affect the translation of genes that use rare aminoacyl-tRNA isoacceptors to a great extent and might explain the selective activity of AZM on the P. aeruginosa proteome and possibly also on the protein expression profiles of other bacterial pathogens.

Macrolide therapy in chronic inflammatory diseases

Macrolides are a group of antibiotics with a distinctive macrocyclic lactone ring combined with sugars (cladinose, desosamine). The action of macrolides is to block protein synthesis by binding to the subunit of 50S ribosome of bacteria. Prototype macrolide was erythromycin, which came into clinical practice in the 50s of the 20th century. Its antimicrobial spectrum covers the scope of the penicillins but is extended to the impact of atypical bacteria. In the 90s more drugs of this group were synthesized—they have less severe side effects than erythromycin, extended spectrum of Gram-negative bacteria. Macrolides are effective in treating mycobacterial infections especially in patients infected with HIV. It is now known that in addition to antibacterial abilities, macrolides have immunomodulatory effects—they inhibit the production of proinflammatory cytokines (TNF, IL1, 6, and 8) affect transcription factors (NF-κB) as well as costimulaton (CD 80) and adhesion molecules (ICAM). This review article focused not only on the their antimicrobial abilities but also on efficacy in the treatment of several inflammatory disorders independent of the infectious agent. Their wider use as immunomodulators requires further study, which can lead to an extension of indications for their administration.

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.

Clarithromycin suppresses human respiratory syncytial virus infection-induced Streptococcus pneumoniae adhesion and cytokine production in a pulmonary epithelial cell line

Human respiratory syncytial virus (RSV) sometimes causes acute and severe lower respiratory tract illness in infants and young children. RSV strongly upregulates proinflammatory cytokines and the platelet-activating factor (PAF) receptor, which is a receptor for Streptococcus pneumoniae, in the pulmonary epithelial cell line A549. Clarithromycin (CAM), which is an antimicrobial agent and is also known as an immunomodulator, significantly suppressed RSV-induced production of interleukin-6, interleukin-8, and regulated on activation, normal T-cell expressed and secreted (RANTES). CAM also suppressed RSV-induced PAF receptor expression and adhesion of fluorescein-labeled S. pneumoniae cells to A549 cells. The RSV-induced S. pneumoniae adhesion was thought to be mediated by the host cell's PAF receptor. CAM, which exhibits antimicrobial and immunomodulatory activities, was found in this study to suppress the RSV-induced adhesion of respiratory disease-causing bacteria, S. pneumoniae, to host cells. Thus, CAM might suppress immunological disorders and prevent secondary bacterial infections during RSV infection.

Erythromycin enhances CD4+Foxp3+ regulatory T-cell responses in a rat model of smoke-induced lung inflammation

Heavy smoking can induce airway inflammation and emphysema. Macrolides can modulate inflammation and effector T-cell response in the lungs. However, there is no information on whether erythromycin can modulate regulatory T-cell (Treg) response. This study is aimed at examining the impact of erythromycin on Treg response in the lungs in a rat model of smoking-induced emphysema. Male Wistar rats were exposed to normal air or cigarette smoking daily for 12 weeks and treated by gavage with 100 mg/kg of erythromycin or saline daily beginning at the forth week for nine weeks. The lung inflammation and the numbers of inflammatory infiltrates in bronchoalveolar lavage fluid (BALF) were characterized. The frequency, the number of Tregs, and the levels of Foxp3 expression in the lungs and IL-8, IL-35, and TNF-α in BALF were determined by flow cytometry, RT-PCR and ELISA, respectively. Treatment with erythromycin reduced smoking-induced inflammatory infiltrates, the levels of IL-8 and TNF-α in the BALF and lung damages but increased the numbers of CD4⁺Foxp3⁺ Tregs and the levels of Foxp3 transcription in the lungs, accompanied by increased levels of IL-35 in the BALF of rats. Our novel data indicated that erythromycin enhanced Treg responses, associated with the inhibition of smoking-induced inflammation in the lungs of rats.

Macrolide therapy and outcomes in a multicenter cohort of children hospitalized with Mycoplasma pneumoniae pneumonia

BACKGROUND

Mycoplasma pneumoniae is a common cause of community-acquired pneumonia in childhood. Few studies have addressed the association of antimicrobial treatment and outcomes.

OBJECTIVE

To determine whether macrolide therapy is associated with improved outcomes among children hospitalized with M. pneumoniae pneumonia.

DESIGN

Multicenter retrospective cohort study.

SETTING

Thirty-six children's hospitals which contribute data to the Pediatric Health Information System.

PATIENTS

Children 6-18 years of age discharged with a diagnosis of M. pneumoniae pneumonia.

MAIN EXPOSURE

Initial macrolide therapy.

MAIN OUTCOME MEASURES

Length of stay (LOS), all-cause readmissions, and asthma-related hospitalizations.

RESULTS

Empiric macrolide therapy was administered to 405 (58.7%) of 690 patients. The median LOS was 3 days (interquartile range, 2-6 days). Eight (1.2 %) patients were readmitted within 28 days, and 160 (23.2%) were readmitted within 15 months of index discharge. Ninety-five (13.7%) patients were hospitalized for asthma within 15 months of index discharge. Empiric macrolide therapy was associated with a 32% shorter overall LOS (adjusted beta-coefficient, -0.38; 95% confidence interval [CI]: -0.59 to -0.17). Macrolide therapy was not associated with all-cause readmission at 28 days (adjusted odds ratio, 1.12; 95% CI: 0.22-5.78) or 15 months (adjusted odds ratio, 1.00; 95% CI: 0.59-1.70) or with asthma-related hospitalizations at 15 months (adjusted odds ratio, 0.85; 95% CI: 0.36-1.97).

CONCLUSION

In this large multicenter study of children hospitalized with M. pneumoniae pneumonia, empiric macrolide therapy was associated with a shorter hospital LOS. Macrolide therapy was not associated with 28-day or 15-month hospital readmission.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Genetic predisposition to diffuse panbronchiolitis

Diffuse panbronchiolitis is characterized by chronic inflammation in respiratory bronchioles and sinobronchial infection. The pathophysiology accompanying the persistent bacterial infection is noteworthy for the accumulation of lymphocytes and foamy macrophages around the small airways, for mucus hypersecretion, and for the number of neutrophils in the large airways. Until the establishment of long-term macrolide therapy, the prognosis was generally poor. Case studies of diffuse panbronchiolitis in East Asians, including Japanese, Koreans and Chinese, have frequently been reported, and genetic predisposition to the disease has been assumed in Asians. Immunogenetic studies revealed a strong association with human leukocyte antigen (HLA)-B54 in Japanese, whereas an association with HLA-A11 was reported in Koreans. These findings imply that a major susceptibility gene may be located between the HLA-A and HLA-B loci on the short arm of human chromosome 6. We have recently cloned novel mucin-like genes in this candidate region. In addition to accumulated knowledge of classical HLA genes and mucin genes, further analysis of newly identified genes may provide insights into the pathogenesis of the disease.

Clarithromycin for prevention of bronchiolitis obliterans syndrome in lung allograft recipients

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Effect of azithromycin on patients with diffuse panbronchiolitis: retrospective study of 51 cases

BACKGROUND

Patients with diffuse panbronchiolitis (DPB) are routinely treated with erythromycin, clarithromycin, and roxithromycin. The clinical effect of azithromycin on DPB has not been confirmed in a large cohort.

OBJECTIVE

The present study was undertaken to investigate the clinical effects of azithromycin on patients with DPB.

METHODS

Fifty-one patients with DPB treated with azithromycin in Shanghai Pulmonary Hospital, China, from July 2001 to April 2007 were analyzed retrospectively. Azithromycin (500 mg a day) was administrated intravenously in the first 1-2 weeks, taken orally (500 mg, once a day) for 3 months, and tapered to 3 times a week for 6-12 months. The patients were followed up until September 1, 2009. The therapeutic effect, according to their clinical and radiological findings, arterial gas analysis, lung function, and sputum bacterium before and after the therapy, was categorized into the following five grades: 1) cured; 2) improved; 3) no response; 4) aggravation, and 5) relapse.

RESULTS

With azithromycin therapy, 14 (27.5%) patients with DPB were completely cured. The symptoms were eliminated to certain degrees for the other 36 cases (70.6%) of DPB. Five-year survival in this cohort was 94.1%.

CONCLUSION

Azithromycin is effective and well tolerated for patients with diffuse panbronchiolitis.

Suppression of nitric oxide production from nasal fibroblasts by metabolized clarithromycin in vitro

Background

Low-dose and long-term administration of 14-membered macrolide antibiotics, so called macrolide therapy, has been reported to favorably modify the clinical conditions of chronic airway diseases. Since there is growing evidence that macrolide antibiotic-resistant bacteria's spreaders in the populations received macrolide therapy, it is strongly desired to develop macrolide antibiotics, which showed only anti-inflammatory action. The present study was designed to examine the influence of clarithromycin (CAM) and its metabolized materials, M-1, M-4 and M-5, on free radical generation from nasal polyp fibroblasts (NPFs) through the choice of nitric oxide (NO), which is one of important effector molecule in the development of airway inflammatory disease in vitro.

Methods

NPFs (5 × 10⁵ cells/ml) were stimulated with 1.0 μg/ml lipopolysaccharide (LPS) in the presence of agents for 24 hours. NO levels in culture supernatants were examined by the Griess method. We also examined the influence of agents on the phosphorylation of MAPKs, NF-κB activation, iNOS mRNA expression and iNOS production in NPFs cultured for 2, 4, 8, and 12 hours, respectively.

Results

The addition of CAM (> 0.4 μg/ml) and M-4 (> 0.04 μg/ml) could suppress NO production from NPFs after LPS stimulation through the suppression of iNOS mRNA expression and NF-κB activation. CAM and M-4 also suppressed phosphorylation of MAPKs, ERK and p38 MAPK, but not JNK, which are increased LPS stimulation. On the other hand, M-1 and M-5 could not inhibit the NO generation, even when 0.1 μg/ml of the agent was added to cell cultures.

Conclusion

The present results may suggest that M-4 will be a good candidate for the agent in the treatment of chronic airway inflammatory diseases, since M-4 did not have antimicribiological effects on gram positive and negative bacteria.

Beneficial and Harmful Interactions of Antibiotics with Microbial Pathogens and the Host Innate Immune System

In general antibiotics interact cooperatively with host defences, weakening and decreasing the virulence of microbial pathogens, thereby increasing vulnerability to phagocytosis and eradication by the intrinsic antimicrobial systems of the host. Antibiotics, however, also interact with host defences by several other mechanisms, some harmful, others beneficial. Harmful activities include exacerbation of potentially damaging inflammatory responses, a property of cell-wall targeted agents, which promotes the release of pro-inflammatory microbial cytotoxins and cell-wall components. On the other hand, inhibitors of bacterial protein synthesis, especially macrolides, possess beneficial anti-inflammatory/cytoprotective activities, which result from interference with the production of microbial virulence factors/cytotoxins. In addition to these pathogen-directed, anti-inflammatory activities, some classes of antimicrobial agent possess secondary anti-inflammatory properties, unrelated to their conventional antimicrobial activities, which target cells of the innate immune system, particularly neutrophils. This is a relatively uncommon, potentially beneficial property of antibiotics, which has been described for macrolides, imidazole anti-mycotics, fluoroquinolones, and tetracyclines. Although of largely unproven significance in the clinical setting, increasing awareness of the pro-inflammatory and anti-inflammatory properties of antibiotics may contribute to a more discerning and effective use of these agents.

Pathology of small airways disease

CONTEXT

The term small airways disease encompasses a generally poorly understood group of lung diseases that may arise primarily within the small airways or secondarily from diseases primarily affecting the bronchi or lung parenchyma. Their histology may be confusing; however, because treatments and prognoses vary, correct pathologic diagnosis is important.

OBJECTIVE

To present a nonexhaustive review of the pathology of primary and secondary small airways diseases, including small airways disease related to tobacco; to various other exposures, including mineral dusts; to diseases involving other areas of the lung with secondary bronchiolar involvement; and to recently described bronchiolitic disorders.

DATA SOURCES

Current literature is reviewed.

CONCLUSIONS

Small airways diseases include a wide variety of diseases of which the pathologist must consider. Uncommon conditions such as diffuse idiopathic neuroendocrine cell hyperplasia and diffuse panbronchiolitis may show relatively specific diagnostic features histologically; however, most small airways diseases exhibit nonspecific histologic features. Conditions not considered primary pulmonary diseases, such as collagen vascular diseases, bone marrow transplantation, and inflammatory bowel disease, must also be considered in patients with small airways changes histologically. Clinical and radiologic correlation is important for obtaining the best possible diagnosis.

Diffuse panbronchiolitis: not just an Asian disease: Australian case series and review of the literature

Diffuse panbronchiolitis is a disease of obscure aetiology that is traditionally associated with Asian ethnicity. We propose that this disease also occurs in Caucasians and the incidence in this population is greater than currently recognised. We further propose that high resolution computed tomography (HRCT) and response to macrolide therapy should be relied upon to make this diagnosis without verification by lung biopsy. In most circumstances, obtaining a biopsy for histopathology is not practical, and the disease may then be mistaken for other more common airway diseases. Accuracy of diagnosis is important as untreated disease is associated with a poor prognosis, and effective treatment is available. We report four out of a series of cases as evidence that DPB is in fact more common in the Western population than is currently understood.

A low concentration of azithromycin inhibits the mRNA expression of N-acyl homoserine lactone synthesis enzymes, upstream of lasI or rhlI, in Pseudomonas aeruginosa

Low-dose macrolides are effective therapy in patients with chronic lung infections, but the mechanisms of action are unclear. In this study, we performed DNA microarray analysis of Pseudomonas aeruginosa after treatment with a low concentration of azithromycin. We found that a sub-MIC of azithromycin didn't change mRNA expression of quorum-sensing related genes (lasI, lasR, rhlI, rhlR, vft, rsaL), but lowered expression of most N-acyl homoserine lactone (AHL) synthesis enzymes upstream of lasI and rhlI. We propose that small down regulation of these enzymes cumulatively resulted in a larger decrease of AHL production and inhibition of quorum-sensing in P. aeruginosa.

Chronic inflammation in the cystic fibrosis lung: alterations in inter- and intracellular signaling

A vicious cycle of airway obstruction, infection, and inflammation continues to cause most of the morbidity and mortality in cystic fibrosis (CF). Mutations that result in decreased expression or function of the membrane Cl(-) channel, cystic fibrosis transmembrane regulator (CFTR), result in a decrease in the volume (and hence the depth) of liquid on the airway surface, impaired ciliary function, and dehydrated glandular secretions. In turn, these abnormalities contribute to a milieu, which promotes chronic infection with a limited but unique spectrum of microorganisms. Defects in CFTR also perturb regulation of several intracellular signaling pathways including signal transducers and activator of transcription, I-kappaB and nuclear factor-kappa B, and low molecular weight GTPases. Together, these abnormalities result in excessive production of NF-kappaB dependent cytokines such as interleukin (IL)-1, tumor necrosis factor (TNF), IL-6, and IL-8. There are decreased responses to interferon gamma and transforming growth factor beta leading to decreased production of iNOS and NO. Abnormalities of lipid mediators and decreased secretion of counter/regulatory cytokines have also been reported. Together, these effects combine to create a chronic inflammatory process, which damages and obstructs the airways, and eventually claims the life of the patient.

Suppression of oxidant-induced glutathione synthesis by erythromycin in human bronchial epithelial cells

BACKGROUND

Macrolide antibiotics have anti-inflammatory effects which are utilized for the treatment of chronic inflammatory airway diseases. Recently, their anti-inflammatory effects have been proposed to be beneficial in patients with chronic obstructive pulmonary disease (COPD).

OBJECTIVES

Since the molecular mechanisms of anti-inflammatory effects are associated with inhibition of activator protein 1 (AP-1) and nuclear factor (NF)-kappaB, and both are reported to be involved in the expression of gamma-glutamylcysteine synthetase (gamma-GCS), we set out to determine if these drugs influence the oxidant-antioxidant balance in human bronchial epithelial (HBE) cells.

METHODS

16HBE cells were preincubated with erythromycin (EM) at different concentrations and times and then exposed to hydrogen peroxide (0.01 mM). Levels of interleukin (IL)-8 and glutathione (GSH), and activity of gamma-GCS and gamma-GCS heavy subunit (gamma-GCS-HS) protein production were assayed. AP-1 and NF-kappaB binding to the 5'-flanking region of IL-8 and gamma-GCS-HS genes was assessed by electrophoretic mobility-shift assay.

RESULTS

The increase in IL-8 levels and activity of AP-1 induced by H(2)O(2) were abrogated by preincubation of the cells with EM (5 mug/ml) for 36 h. We also showed that preincubation with EM for 48 h inhibited H(2)O(2)-induced GSH levels, gamma-GCS activity and expression of gamma-GCS-HS, and decreased AP-1 binding to the gamma-GCS-HS 5'-flanking region.

CONCLUSIONS

The confirmation of antioxidants maintaining enzyme suppression by EM raised concerns on whether this drug could disrupt the oxidant/ antioxidant balance during long-term use. These data provide important insights into the treatment of inflammatory lung diseases with macrolide antibiotics.

Follicular bronchiolitis in surgical lung biopsies: clinical implications in 12 patients

BACKGROUND

Follicular bronchiolitis is a histopathologic finding that occurs in diverse clinical contexts. The current study was conducted to characterize clinico-radiologic features, and assess outcomes associated with follicular bronchiolitis.

SUBJECTS AND METHODS

Twelve subjects with follicular bronchiolitis on lung biopsy were seen over a 9-year period, between 1996 and 2005. Medical records, biopsy and radiographic findings, and details of outcome at the time of last follow-up were recorded.

RESULTS

The study population included 4 men and 8 women; the median age at diagnosis was 54 years (range, 33-81 years). Four patients had underlying systemic diseases that included: 2 with common variable immunodeficiency, 1 Sjögren's syndrome and 1 undifferentiated connective tissue disease. The diagnosis was obtained by surgical lung biopsy in all cases. Follicular bronchiolitis was the major histologic pattern in 9 patients; organizing pneumonia, nonspecific interstitial pneumonia and usual interstitial pneumonia was seen in 1 patient each with follicular bronchiolitis being an associated secondary histopathologic component. Computed tomographic findings included reticular opacities, small nodules and ground-glass opacities. Clinical course was characterized by relative stability with partial response to immunosuppressive agents. During a median follow-up period of 47 months, only one death occurred--out of 9 patients where the outcome information was available--and was unrelated to lung disease.

CONCLUSIONS

The histologic lesion of follicular bronchiolitis may be seen as the predominant finding or a relatively minor feature in interstitial pneumonias. The clinical course and prognosis for most patients with follicular bronchiolitis is relatively good, and progressive lung disease is uncommon.

63-jährige Türkin mit rezidivierenden Pneumonien

The differential diagnosis of a sinubronchial syndrome includes cystic fibrosis, allergic bronchopulmonic aspergillosis, Kartagener's syndrome, hypogammaglobulinemia and bronchioli-associated processes. The latter include cryptogenic organising pneumonia, constrictive bronchiolitis obliterans as well as the respiratory bronchiolitis. Our case presented a persistent interstitial shadow in the x-rax of the thorax and a relevant, mixed ventilation disturbance in lung function. A surgically performed lung biopsy finally allowed the diagnosis of diffuse panbronchiolitis, which is seldom found in central Europe. This disease is of unknown etiology and responds to long-term macrolide therapy.

Defect in early lung defence against Pseudomonas aeruginosa in DBA/2 mice is associated with acute inflammatory lung injury and reduced bactericidal activity in naive macrophages

Pseudomonas aeruginosa is an opportunistic pathogen that causes serious respiratory disease in the immune-compromised host. Using an aerosol infection model, 11 inbred mouse strains (129/Sv, A/J, BALB/c, C3H/HeN, C57BL/6, DBA/2, FVB, B10.D2/oSnJ, B10.D2/nSnJ, AKR/J and SWR/J) were tested for increased susceptibility to P. aeruginosa lung colonization. DBA/2 was the only mouse strain that had increased bacterial counts in the lung within 6 h post-infection. This deficiency incited a marked inflammatory response with reduced bacterial lung clearance and a mortality rate of 96.7 %. DBA/2 mice displayed progressive deterioration of lung pathology with extensive alveolar exudate and oedema formation at 48-72 h post-infection. The neutrophil-specific myeloperoxidase activity remained elevated throughout infection, suggesting that the increased leukocyte infiltration into alveoli caused acute inflammatory lung injury. DBA/2 mice lack the haemolytic complement; however, three additional mouse strains (AKR/J, SWR/J and A/J) with the same defect effectively cleared the infection, indicating that other host factors are involved in defence. Bone marrow-derived macrophages of DBA/2 showed an initial increase in phagocytosis, while their bactericidal activity was reduced compared to that of C57BL/6 macrophages. Comparison of pulmonary cytokine profiles of DBA/2 versus C57BL/6 or C3H/HeN indicated that DBA/2 had similar increases in tumour necrosis factor (TNF)-alpha, KC and interleukin (IL)-1a as C3H/HeN, but showed specific induction of IL-17, monocyte chemotactic protein (MCP)-1 and vascular endothelial growth factor (VEGF). Together, DBA/2 mice have a defect in the initial lung defence against P. aeruginosa colonization, which causes the host to produce a greater, but damaging, inflammatory response. Such a response may originate from the reduced antimicrobial activity of DBA/2 macrophages.

Roxithromycin inhibits transforming growth factor-? production by cultured human mesangial cells

BACKGROUND

Transforming growth factor-beta (TGF-beta) plays an important role in progression of renal injury. However, few materials which inhibit TGF-beta have been known. Roxithromycin (ROX), macrolide antibiotics, is known to have anti-inflammatory, immunomodulatory and tissue reparative effects besides its bacteriostatic activity, although the exact mechanism of its anti-inflammatory and immunomodulatory effects was not defined. We examined the effect of ROX on production of TGF-beta and type IV collagen by cultured human mesangial cells (HMC).

METHODS

Human mesangial cells were incubated with several concentrations of ROX and TGF-beta and type IV collagen levels in the culture supernatants were measured by enzyme-linked immunoassay. Amount of TGF-beta mRNA was also quantified by using a colourimetric mRNA quantification kit and semiquantitative reverse transcriptase polymerase chain reaction. We also examined the effect of ROX on tyrosine kinase, MAP kinase and NF-kappaB stimulated by thrombin.

RESULTS

Roxithromycin (0.1-10.0 microg/mL) inhibited TGF-beta production by HMC in a dose- and time-dependent manner without inducing cell injury. ROX (10.0 microg/mL) also inhibited mRNA expression of TGF-beta in HMC. Thrombin (5 U/mL) stimulated TGF-beta production by HMC and ROX significantly inhibited the stimulating effect of thrombin on TGF-beta production. ROX also inhibited the increment of type IV collagen production stimulated by thrombin. ROX (10.0 microg/mL) suppressed the thrombin-induced NF-kappaB activation, although ROX did not inhibit the activation of tyrosine kinase and MAP kinase by thrombin.

CONCLUSION

Roxithromycin has an inhibitory effect on TGF-beta production by HMC possibly via inhibition of NF-kappaB. ROX may be a potential agent for the treatment of glomerulosclerosis.

NKT cells play a limited role in the neutrophilic inflammatory responses and host defense to pulmonary infection with Pseudomonas aeruginosa

CD1d-restricted NKT cells are reported to play a critical role in the host defense to pulmonary infection with Pseudomonas aeruginosa. However, the contribution of a major subset expressing a Valpha14-Jalpha18 gene segment remains unclear. In the present study, we re-evaluated the role of NKT cells in the neutrophilic inflammatory responses and host defense to this infection using mice genetically lacking Jalpha18 or CD1d (Jalpha18KO or CD1dKO mice). These mice cleared the bacteria in lungs at a comparable level to wild-type (WT) mice. There was no significant difference in the local neutrophilic responses, as shown by neutrophil counts and synthesis of MIP-2 and TNF-alpha, in either KO mice from those in WT mice. Administration of alpha-galactosylceramide, a specific activator of Valpha14+ NKT cells, failed to promote the bacterial clearance and neutrophilic responses, although the same treatment increased the synthesis of IFN-gamma, suggesting the involvement of this cytokine downstream of NKT cells. In agreement against this notion, these responses were not further enhanced by administration of recombinant IFN-gamma in the infected Jalpha18KO mice. Our data indicate that NKT cells play a limited role in the development of neutrophilic inflammatory responses and host defense to pulmonary infection with P. aeruginosa.

Novel effects of azithromycin on tight junction proteins in human airway epithelia

The macrolide antibiotic azithromycin improves lung function and prognosis among patients with cystic fibrosis or diffuse panbronchiolitis, independently of bacterial eradication. Anti-inflammatory effects have been implicated, but data from in vivo studies are scarce, and the link between abnormal electrolyte content in airway surface liquid and bronchial infections remains uncertain. In the present study, we treated human airway epithelia on filter supports with azithromycin and monitored transepithelial electrical resistance. We found that azithromycin increased transepithelial electrical resistance of airway epithelia in a dose-dependent manner. Immunocytochemistry and Western blotting showed that addition of azithromycin changed the locations of proteins in cell cultures and induced processing of the tight junction proteins claudin-1 and claudin-4, occludin, and junctional adhesion molecule-A. These effects were reversible, and no effect was seen when cells were treated with penicillin or erythromycin. The data indicate that azithromycin increases the transepithelial electrical resistance of human airway epithelia by changing the processing of tight junction proteins. The results are novel and may help explain the beneficial effects of azithromycin in patients with cystic fibrosis, diffuse panbronchiolitis, and community-acquired pneumonia.