Mechanism of azithromycin in airway diseases

Azithromycin Mechanisms of Action in CRS Include Epithelial Barrier Restoration and Type 1 Inflammation Reduction

OBJECTIVE

Previous in vitro transcriptomic profiling suggests azithromycin exerts its effects in patients with chronic rhinosinusitis (CRS) via modulation of type 1 inflammation and restoration of epithelial barrier function. We wished to verify these postulated effects using in vitro models of epithelial repair and in vivo transcriptional profiling.

STUDY DESIGN

Functional effects of azithromycin in CRS were verified using in vitro models of wounding. The mechanism of the effect of azithromycin was assessed in vivo using transcriptomic profiling.

SETTING

Academic medical center.

METHODS

Effects of azithromycin on the speed of epithelial repair were verified in a wounding model using primary nasal epithelial cells (pNEC) from CRS patients. Nasal brushings collected pre-and posttreatment during a placebo-controlled trial of azithromycin for CRS patients unresponsive to surgery underwent transcriptomic profiling to identify implicated pathways.

RESULTS

Administration of azithromycin improved the wound healing rates in CRS pNECs and prevented the negative effect of Staphylococcus aureus on epithelial repair. In vivo, response to azithromycin was associated with downregulation in pathways of type 1 inflammation, and upregulation of pathways implicated in the restoration of the cell cycle.

CONCLUSION

Restoration of healthy epithelial function may represent a major mode of action of azithromycin in CRS. In vitro models show enhanced epithelial repair, while in vivo transcriptomics shows downregulation of pathways type 1 inflammation accompanied by upregulation of DNA repair and cell-cycle pathways. The maximal effect in patients with high levels of type 1-enhanced inflammation suggests that azithromycin may represent a novel therapeutic option for surgery-unresponsive CRS patients.

Systemic and functional effects of continuous azithromycin treatment in patients with severe chronic obstructive pulmonary disease and frequent exacerbations

BACKGROUND

Continuous treatment with azithromycin may lead to fewer acute exacerbations of chronic obstructive pulmonary disease (AECOPD), but little is known of its impact on systemic and functional outcomes in real-life settings.

METHODS

This was a multicenter prospective observational study of patients with severe COPD who started treatment with azithromycin. Tests were compared at baseline and after 3 and 12 months of treatment. These included lung function tests, a 6-min walking test (6MWT), and enzyme-linked immunosorbent assays of serum and sputum markers, such as interleukins (IL-6, IL-8, IL-13, IL-5), tumor necrosis factor receptor 2 (TNFR2), and inflammatory markers. Incidence rate ratios (IRR) and their 95% confidence intervals (95% CI) are reported.

RESULTS

Of the 478 eligible patients, the 42 who started azithromycin experienced reductions in AECOPDs (IRR, 0.34; 95% CI, 0.26-0.45) and hospitalizations (IRR, 0.39; 95% CI, 0.28-0.49). Treatment was also associated with significant improvement in the partial arterial pressure of oxygen (9.2 mmHg, 95% CI 1.4-16.9) at 12 months. While TNFR2 was reduced significantly in both serum and sputum samples, IL-13 and IL-6 were only significantly reduced in serum samples. Moreover, an elevated serum and sputum IL-8 level significantly predicted good clinical response to treatment.

CONCLUSION

Continuous azithromycin treatment in a cohort of patients with severe COPD and frequent exacerbations can significantly reduce the number and severity of exacerbations and improve gas exchange. Treatment changes the pattern of microorganism isolates and decreases the inflammatory response. Of note, IL-8 may have utility as a predictor of clinical response to azithromycin treatment.

Preparations and characterizations of effervescent granules containing azithromycin solid dispersion for children and elder: Solubility enhancement, taste-masking, and digestive acidic protection

Azithromycin, a macrolide antibiotics, is one of the frequently used drugs in the children and elder. However, due to these population difficulty in swallowing and inefficient absorption, and azithromycin inherent poor solubility, bitter taste, and instability in the stomach acidic condition, it is a challenge to reach high oral bioavailability of this drug. To overcome these issues, we developed and characterized the effervescent granules containing azithromycin solid dispersion. Firstly, the solid dispersion was prepared, employing both wet grinding and solvent evaporation methods, with different types/amounts of polymers. The optimal solid dispersion with β-cyclodextrin at a drug:polymer ratio of 1:2 (w/w), prepared by the solvent evaporation method, significantly enhanced the azithromycin solubility 4-fold compared to the free drug, improved its bitterness from "bitter" to "normal", possessed intermolecular bonding between the drug and polymer, and transformed the azithromycin molecules from crystalline to amorphous state. Secondly, the effervescent granules incorporating the solid dispersion were formulated with varied excipients of sweeteners, gas-generators, pH modulators, and glidants/lubricants. The optimal formula satisfied all the properties stated in the Vietnamese Pharmacopoeia. In summary, the final effervescent granules product could be further investigated in in-vivo and in clinical settings to become a potential azithromycin delivery system with high bioavailability for the children and elder.

Prospects for macrolide therapy of asthma and COPD

Macrolide compounds, many of which are derived from natural sources, all share a lactone ring structure, but of varying sizes. Their biological activities differ with structure and size but tend to overlap. Marketed macrolide drugs include immunosuppressives and antibiotics. Some of the latter have been shown to exert anti-inflammatory activities, due to direct effects on inflammatory cells and processes when used for respiratory infections. Consequently, azithromycin is included in clinical guidelines for COPD and asthma treatment, though it has the disadvantage, as an antibiotic, of increasing bacterial resistance. COPD and asthma, however, like several chronic inflammatory diseases involving other organs, are driven to a large extent by epithelial barrier dysfunction. Recently, azithromycin was shown to directly enhance epithelial barrier function and a new class of derivatives, barriolides, is under development with the lead indication COPD. It is thus likely that by circumventing antibiosis and acting on a crucial etiological disease process, this type of agent will open up a new, safer approach to COPD and asthma therapy with macrolides.

Clinical Efficacy and In Vitro Drug Sensitivity Test Results of Azithromycin Combined With Other Antimicrobial Therapies in the Treatment of MDR P. aeruginosa Ventilator-Associated Pneumonia

Objective: The aim of the research was to study the effect of azithromycin (AZM) in the treatment of MDR P. aeruginosa VAP combined with other antimicrobial therapies.

Methods: The clinical outcomes were retrospectively collected and analyzed to elucidate the efficacy of different combinations involving azithromycin in the treatment of MDR-PA VAP. The minimal inhibitory concentration (MIC) of five drugs was measured by the agar dilution method against 27 isolates of MDR-PA, alone or in combination.

Results: The incidence of VAP has increased approximately to 10.4% (961/9245) in 5 years and 18.4% (177/961) caused by P. aeruginosa ranking fourth. A total of 151 cases of MDR P. aeruginosa were included in the clinical retrospective study. Clinical efficacy results are as follows: meropenem + azithromycin (MEM + AZM) was 69.2% (9/13), cefoperazone/sulbactam + azithromycin (SCF + AZM) was 60% (6/10), and the combination of three drugs containing AZM was 69.2% (9/13). The curative effect of meropenem + amikacin (MEM + AMK) was better than that of the meropenem + levofloxacin (MEM + LEV) group, p = 0.029 (p < 0.05). The curative effect of cefoperazone/sulbactam + amikacin (SCF + AMK) was better than that of the cefoperazone/sulbactam + levofloxacin (SCF + LEV) group, p = 0.025 (p < 0.05). There was no significant difference between combinations of two or three drugs containing AZM, p > 0.05 (p = 0.806). From the MIC results, the AMK single drug was already very sensitive to the selected strains. When MEM or SCF was combined with AZM, the sensitivity of them to strains can be significantly increased. When combined with MEM and AZM, the MIC₅₀ and MIC₉₀ of MEM decreased to 1 and 2 ug/mL from 8 to 32 ug/mL. When combined with SCF + AZM, the MIC₅₀ of SCF decreased to 16 ug/mL, and the curve shifted obviously. However, for the combination of SCF + LEV + AZM, MIC₅₀ and MIC₉₀ could not achieve substantive changes. From the FIC index results, the main actions of MEM + AZM were additive effects, accounting for 72%; for the combination of SCF + AZM, the additive effect was 40%. The combination of AMK or LEV with AZM mainly showed unrelated effects, and the combination of three drugs could not improve the positive correlation between LEV and AZM.

Conclusion: AZM may increase the effect of MEM or SCF against MDR P. aeruginosa VAP. Based on MEM or SCF combined with AMK or AZM, we can achieve a good effect in the treatment of MDR P. aeruginosa VAP.

A determination of pan-pathogen antimicrobials?

While antimicrobial drug development has historically mitigated infectious diseases that are known, COVID-19 revealed a dearth of 'in-advance' therapeutics suitable for infections by pathogens that have not yet emerged. Such drugs must exhibit a property that is antithetical to the classical paradigm of antimicrobial development: the ability to treat infections by any pathogen. Characterisation of such 'pan-pathogen' antimicrobials requires consolidation of drug repositioning studies, a new and growing field of drug discovery. In this review, a previously-established system for evaluating repositioning studies is used to highlight 4 therapeutics which exhibit pan-pathogen properties, namely azithromycin, ivermectin, niclosamide, and nitazoxanide. Recognition of the pan-pathogen nature of these antimicrobials is the cornerstone of a novel paradigm of antimicrobial development that is not only anticipatory of pandemics and bioterrorist attacks, but cognisant of conserved anti-infective mechanisms within the host-pathogen interactome which are only now beginning to emerge. Ultimately, the discovery of pan-pathogen antimicrobials is concomitantly the discovery of a new class of antivirals, and begets significant implications for pandemic preparedness research in a world after COVID-19.

Giant Hepatic Hemangioma Regressed Significantly Without Surgical Management: A Case Report and Literature Review

Hepatic hemangioma (HH) is a congenital vascular anomaly comprising networks of abnormal blood and/or lymphatic vessels with endothelial cell proliferation. Their pathophysiology is not fully understood, and no specific drug is available to treat them. Conservative management, which limits observation, is preferred for most patients. A HH larger than 4 cm is considered a giant HH that may be treated using surgery ranging from embolization to hepatic resection or liver transplantation. Here, we describe a case with multiple and giant HHs that regressed significantly after treatment with azithromycin (AZM). A systematic literature review of HH and the effects of AZM on angiogenesis was then conducted.

[The effect of glucocorticoids in combination with azithromycin or theophylline on cytokine production by NK and NKT-like blood cells of patients with chronic obstructive pulmonary disease]

Chronic obstructive pulmonary disease (COPD) is characterized by reduced sensitivity of cells to the anti-inflammatory effects of glucocorticoids (GCs). Azithromycin and a low dose theophylline have a significant impact on molecular mechanisms leading to corticosteroid resistance. The aim of this study was to evaluate the ability of azithromycin and theophylline to enhance the anti-inflammatory effects of GCs on the production of cytokines by NK and NKT-like blood cells of COPD patients. Whole blood cells from COPD patients (n=21) were incubated in the presence of budesonide (10 nM), azithromycin (10 μg/mL), theophylline (1 μM), or their combinations and stimulated with phorbol myristate acetate (50 ng/mL). Intracellular production of proinflammatory cytokines in NK (CD3-CD56+) and NKT-like (CD3+CD56+) blood cells was analyzed by flow cytometry. Budesonide reduced synthesis of interleukin 4 (IL-4), CXCL8, tumor necrosis factor α (TNFα) by NK and NKT-like cells, as well as production of interferon γ (IFNγ) by NK cells. Azithromycin suppressed production of IL-4 and CXCL8 by NK and NKT-like cells, and theophylline inhibited IL-4 synthesis by these lymphocytes. The combination of azithromycin and budesonide had a more pronounced inhibitory effect on the production of IL-4 and CXCL8 by NK and NKT-like cells than the effect of these drugs alone. The combination of theophylline and budesonide suppressed synthesis of IL-4 and CXCL8 by NK and NKT-like cells, as well as the production of TNFα and IFNγ by NK cells stronger than budesonide alone. The obtained results demonstrate the benefits for the combined use of GCs with theophylline at a low dose or azithromycin to suppress the inflammatory process in patients with COPD.