zithromax and Airway-Remodeling

Steroid resistance in asthma has been associated with neutrophilic inflammation and severe manifestations of the disease. Macrolide add-on therapy can improve the quality of life and the exacerbation rate in refractory cases, possibly with greater effectiveness in neutrophilic phenotypes. The mechanisms leading to these beneficial effects are incompletely understood and whether macrolides potentiate the modulation of bronchial remodeling induced by inhaled corticosteroids (ICS) is unknown. The objective of this study was to determine if adding azithromycin to ICS leads to further improvement of lung function, airway inflammation and bronchial remodeling in severe asthma. The combination of azithromycin (10 mg/kg q48h PO) and inhaled fluticasone (2500 µg q12h) was compared to the sole administration of fluticasone for five months in a randomized blind trial where the lung function, airway inflammation and bronchial remodeling (histomorphometry of central and peripheral airways and endobronchial ultrasound) of horses with severe neutrophilic asthma were assessed. Although the proportional reduction of airway neutrophilia was significantly larger in the group receiving azithromycin, the lung function and the peripheral and central airway smooth muscle mass decreased similarly in both groups. Despite a better control of airway neutrophilia, azithromycin did not potentiate the other clinical effects of fluticasone.

Topics: Administration, Inhalation; Airway Remodeling; Animals; Anti-Bacterial Agents; Asthma; Azithromycin; Bronchodilator Agents; Drug Therapy, Combination; Female; Fluticasone; Horse Diseases; Horses; Male; Neutrophils

Neutrophilic inflammation is believed to contribute to the airway obstruction and remodelling in equine asthma. Azithromycin, an antibiotic with immunomodulatory properties, reduces pulmonary neutrophilia and hyper-responsiveness in human asthmatics and decreases airway remodelling in rodent models of asthma. It was therefore hypothesised that azithromycin would improve lung function, mucus accumulation and central airway remodelling by decreasing luminal neutrophilia in severe equine asthma. The effects of a 10-day treatment with either azithromycin or ceftiofur, an antimicrobial without immune-modulating activity, were assessed using a blind, randomised, crossover design with six severe asthmatic horses in clinical exacerbation. Lung function, tracheal mucus accumulation, tracheal wash bacteriology, bronchial remodelling, airway neutrophilia and mRNA expression of proinflammatory cytokines (interleukin (IL)-8, IL-17A, IL-1β, tumour necrosis factor-α) in bronchoalveolar lavage fluid were evaluated. Azithromycin decreased the expression of IL-8 (P=0.03, one-tailed) and IL-1β (P=0.047, one-tailed) but failed to improve the other variables evaluated. Ceftiofur had no effect on any parameter. The reduction of neutrophilic chemoattractants (IL-8, IL-1β) justifies further efforts to investigate the effects of a prolonged treatment with macrolides on airway neutrophilia and remodelling. The lack of efficacy of ceftiofur suggests that severe equine asthma should not be treated with antibiotics at first-line therapy.

Topics: Airway Remodeling; Animals; Asthma; Azithromycin; Cross-Over Studies; Female; Horse Diseases; Horses; Immunologic Factors; Inflammation; Lung; Male; Mucus; Respiratory Function Tests; Trachea

Dysregulated airway epithelial repair following injury is a proposed mechanism driving posttransplant bronchiolitis obliterans (BO), and its clinical correlate bronchiolitis obliterans syndrome (BOS). This study compared gene and cellular characteristics of injury and repair in large (LAEC) and small (SAEC) airway epithelial cells of transplant patients.. Subjects were recruited at the time of routine bronchoscopy posttransplantation and included patients with and without BOS. Airway epithelial cells were obtained from bronchial and bronchiolar brushing performed under radiological guidance from these patients. In addition, bronchial brushings were also obtained from healthy control subjects comprising of adolescents admitted for elective surgery for nonrespiratory-related conditions. Primary cultures were established, monolayers wounded, and repair assessed (±) azithromycin (1 µg/mL). In addition, proliferative capacity as well as markers of injury and dysregulated repair were also assessed.. SAEC had a significantly dysregulated repair process postinjury, despite having a higher proliferative capacity than large airway epithelial cells. Addition of azithromycin significantly induced repair in these cells; however, full restitution was not achieved. Expression of several genes associated with epithelial barrier repair (matrix metalloproteinase 7, matrix metalloproteinase 3, the integrins β6 and β8, and β-catenin) were significantly different in epithelial cells obtained from patients with BOS compared to transplant patients without BOS and controls, suggesting an intrinsic defect.. Chronic airway injury and dysregulated repair programs are evident in airway epithelium obtained from patients with BOS, particularly with SAEC. We also show that azithromycin partially mitigates this pathology.

Topics: Adolescent; Adult; Airway Remodeling; Allografts; Azithromycin; Bronchi; Bronchiolitis Obliterans; Bronchoscopy; Case-Control Studies; Cells, Cultured; Child; Drug Evaluation, Preclinical; Epithelial Cells; Female; Graft Rejection; Humans; Lung Transplantation; Male; Middle Aged; Primary Cell Culture; Regeneration; Transplantation, Homologous; Young Adult

Airway smooth muscle (ASM) plays a major role in acute airway narrowing and reducing ASM thickness is expected to attenuate airway hyper-responsiveness and disease burden. There are two therapeutic approaches to reduce ASM thickness: (a) a direct approach, targeting specific airways, best exemplified by bronchial thermoplasty (BT), which delivers radiofrequency energy to the airway via bronchoscope; and (b) a pharmacological approach, targeting airways more broadly. An example of the less well-established pharmacological approach is the calcium-channel blocker gallopamil which in a clinical trial effectively reduced ASM thickness; other agents may act similarly. In view of established anti-proliferative properties of the macrolide antibiotic azithromycin, we examined its effects in naive mice and report a reduction in ASM thickness of 29% (p < .01). We further considered the potential functional implications of this finding, if it were to extend to humans, by way of a mathematical model of lung function in asthmatic patients which has previously been used to understand the mechanistic action of BT. Predictions show that pharmacological reduction of ASM in all airways of this magnitude would reduce ventilation heterogeneity in asthma, and produce a therapeutic benefit similar to BT. Moreover there are differences in the expected response depending on disease severity, with the pharmacological approach exceeding the benefits provided by BT in more severe disease. Findings provide further proof of concept that pharmacological targeting of ASM thickness will be beneficial and may be facilitated by azithromycin, revealing a new mode of action of an existing agent in respiratory medicine.

Topics: Airway Remodeling; Animals; Asthma; Azithromycin; Lung; Male; Mice, Inbred BALB C; Models, Biological; Models, Theoretical; Muscle, Smooth

Azithromycin is a potent agent that prevents airway remodeling. In this study, we hypothesized that azithromycin (35 mg/kg orally) alleviated airway remodeling through suppression of epithelial-to-mesenchymal transition (EMT) via downregulation of transforming growth factor-beta 1 (TGF-β1)/receptor for activated C-kinase1 (RACK1)/snail in mice. An ovalbumin (OVA)-induced Balb/c mice airway allergic inflammatory model was used. Airway inflammation and remodeling were evaluated with hematoxylin and eosin (HE), periodic acid-Schiff (PAS), and Masson staining. E-cadherin and N-cadherin (molecular markers of EMT) were analyzed by immunofluorescence, quantitative reverse transcriptase polymerase chain reaction (qRT-PCR), and western blotting; α-smooth muscle actin (α-SMA) was evaluated using immunohistochemistry (IHC), qRT-PCR, and western blotting; and expression of TGF-β1/RACK1/Snail in lungs was measured by qRT-PCR and western blotting. Our data showed that azithromycin significantly reduced inflammation score, peribronchial smooth muscle layer thickness, goblet cell metaplasia, and deposition of collage fibers (P < 0.05), and effectively suppressed airway EMT (upregulated E-cadherin level, and downregulated N-cadherin and α-SMA levels) compared with the OVA group (P < 0.05). Moreover, the increasing mRNA and protein expressions of TGF-β1 and RACK1 and mRNA level of Snail in lung tissue were all significantly decreased in azithromycin-treated mice (P < 0.05). Taken together, our results suggest that azithromycin has the greatest effects on reducing airway remodeling by inhibiting TGF-β1/RACK1/Snail signal and improving the EMT in airway epithelium.

Topics: Airway Remodeling; Allergens; Animals; Anti-Bacterial Agents; Asthma; Azithromycin; Disease Models, Animal; Epithelial-Mesenchymal Transition; Humans; Male; Mice; Mice, Inbred BALB C; Ovalbumin; Receptors for Activated C Kinase; Respiratory Mucosa; Snail Family Transcription Factors; Transforming Growth Factor beta1

Azithromycin can benefit treating allergic airway inflammation and remodeling. In the present study, we hypothesized that azithromycin alleviated airway epithelium injury through inhibiting airway epithelium apoptosis via down regulation of caspase-3 and Bax/Bcl2 ratio in vivo and in vitro.. Ovalbumin induced rat asthma model and TGF-β1-induced BEAS-2B cell apoptosis model were established, respectively. In vivo experiments, airway epithelium was stained with hematoxylin and eosin (HE) and periodic acid-Schiff (PAS) to histologically evaluate the airway inflammation and remodeling. Airway epithelium apoptotic index (AI) was further analyzed by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL), while expression of apoptosis related gene (Bax, Bcl2, Caspase-3) in lungs were measured by qRT-PCR and western blotting, respectively. In vitro experiments, apoptosis were evaluated by Flow cytometry (FCM) and TUNEL. Above apoptosis related gene were also measured by qRT-PCR and western blotting.. Compared with the OVA group, azithromycin significantly reduced the inflammation score, peribronchial smooth muscle layer thickness, epithelial thickening and goblet cell metaplasia (P<0.05), and effectively suppressed AI of airway epithelium (P<0.05). Moreover, the increasing mRNA and protein expressions of Caspase-3 and Bax/Bcl-2 ratio in lung tissue were all significantly decreased in azithromycin-treated rats (P<0.05). In vitro, azithromycin significantly suppressed TGF-β1-induced BEAS-2B cells apoptosis (P<0.05) and reversed TGF-β1 elevated Caspase-3 mRNA level and Bax/Bcl-2 ratio (P<0.05).. Azithromycin is an attractive treatment option for reducing airway epithelial cell apoptosis by improving the imbalance of Bax/Bcl-2 ratio and inhibiting Caspase-3 level in airway epithelium.

Topics: Airway Remodeling; Animals; Apoptosis; Asthma; Azithromycin; bcl-2-Associated X Protein; Caspase 3; Cell Line; Endothelium, Vascular; Epithelium; Flow Cytometry; In Situ Nick-End Labeling; Inflammation; Lung; Male; Ovalbumin; Proto-Oncogene Proteins c-bcl-2; Rats; Rats, Sprague-Dawley; Transforming Growth Factor beta1