Macrolide antibiotics possess a variety of actions other than antimicrobial activities. To determine the effects of long-term administration of clarithromycin (CAM) on the amount and physical properties of sputum in patients with clinical conditions associated with excessive airway secretions, we conducted the present study in a parallel, double-blind, placebo-controlled fashion. Patients were divided into two groups: the first group (n ‫؍‬ 16) received CAM (100 mg, twice a day) for 8 weeks, and the second group (n ‫؍‬ 15) received placebo. In evaluating airway secretion, the daily amount of expectorated sputum, solid composition, viscoelastic properties (including elastic modulus and dynamic viscosity), and sputum microbiology were assessed. CAM decreased sputum production from 51 ؎ 6 to 24 ؎ 3 g/day after treatment, whereas placebo had no effect. The bacterial density and sputum flora were unaltered. In the group receiving CAM, the percent solid composition and elastic modulus increased from 2.44% ؎ 0.29% to 3.01% ؎ 0.20% and 66 ؎ 7 to 87 ؎ 8 dyne/cm 2 (P < 0.05), respectively, but the dynamic viscosity remained unchanged. These results suggest that long-term treatment with CAM reduces the amount of sputum production, probably by inhibiting airway secretions, and increases sputum elasticity.There is increasing evidence that long-term administration of the macrolide antibiotic erythromycin is effective in the treatment of chronic respiratory infections, probably through actions other than its antimicrobial properties (6). Although the mechanism of the efficacy is uncertain, several hypotheses have been proposed, such as immunomodulatory action on inflammatory cells (1,8), inhibition of glycoconjugate secretion from submucosal glands (3), and inhibition of airway epithelial chloride transport and the concomitant secretion of water (12). However, the effects of newly developed macrolides on airway secretion are unknown. Therefore, to investigate whether longterm treatment with oral clarithromycin (CAM) alters sputum production and its rheological properties, we conducted a placebo-controlled trial with a group of patients with chronic bronchitis, bronchiectasis, or diffuse panbronchiolitis. Diffuse panbronchiolitis is a recently described clinicopathologic condition which is found in Japanese, Chinese, and Korean populations and which is characterized by severe, chronic airflow limitation and excessive sputum production accompanied by persistent sinopulmonary infection, respiratory bronchiolitis, and peribronchiolitis (4). MATERIALS AND METHODSPatients. Thirty-one patients, 33 to 77 years of age, who had chronic bronchitis, bronchiectasis, or diffuse panbronchiolitis and who had been continuously expectorating more than 30 g of sputum per day for at least 2 weeks prior to the study were selected after their consent was obtained. All cases of chronic bronchitis conformed to the World Health Organization's definition of the disease (15), and all patients with chronic bronchitis were or had been heavy smokers. Bronc...

We studied the effects of macrolides on lipopolysaccharide (LPS)-induced airway goblet cell secretion in the guinea pig trachea. The goblet cell secretion was assessed in histological sections of the tracheal mucosa stained with alcian blue and periodic acid Schiff by arbitrarily determining mucus score, which is inversely related to the magnitude of mucus discharge. Inhalation of Escherichia coli LPS (5 mg/kg) caused a time-dependent decrease in mucus score, with the maximal response being from 542 +/- 49 to 92 +/- 20 arbitrary units (P < 0.001) after 3 h, which was accompanied by an increase in the number of neutrophils in the tracheal mucosa. The LPS-induced mucus discharge was inhibited by oral clarithromycin and erythromycin in a dose-dependent manner (5 and 10 mg/kg), whereas amoxicillin and cefaclor had no effect. Each dose of clarithromycin and erythromycin, but not amoxicillin or cefaclor, likewise attenuated the LPS-induced recruitment of neutrophils. These results suggest that LPS stimulates goblet cell secretion and neutrophil accumulation in the airways and that macrolides may be of value in protecting against neutrophil-associated airway hypersecretion.

We studied the effects of macrolides on lipopolysaccharide (LPS)-induced airway inflammation in the rat tracheal mucosa. Erythromycin and roxithromycin dose dependently inhibited microvascular leakage and neutrophil recruitment induced by LPS. This inhibitory action on vascular permeability was abolished by neutrophil depletion.There is increasing evidence that macrolide antibiotics modulate the functions of inflammatory cells such as polymorphonuclear leukocytes, lymphocytes, and macrophages (11) and directly affect airway secretory cell (5) and epithelial cell (14) functions. These effects are proposed to reflect the efficacy of macrolides in the treatment of inflammatory airway diseases (4, 9). In the present study, we characterized the effects of lipopolysaccharide (LPS) on vascular permeability and granulocyte recruitment in central airways and determined whether these changes were altered by erythromycin and roxithromycin (12).Pathogen-free male Sprague-Dawley rats were divided into three treatment groups and orally given placebo, erythromycin (DAINABOT Co., Tokyo, Japan), or roxithromycin (Roussel Uclaf, Paris, France) at a daily dose of 1, 5, or 10 mg/kg of body weight for 1 week. The rats were anesthetized and injected with Monastral blue suspension (30 mg/kg; Sigma, St. Louis, Mo.) in the femoral vein (8). Immediately after the injection, LPS (Escherichia coli 026:B6, 1 mg/kg; Sigma) was administered intravenously to produce airway inflammatory reactions. At selected intervals, fixative (1% paraformaldehyde and saline in 50 mM phosphate buffer) was perfused through the left ventricle to wash Monastral blue pigments out of the vasculature. Then the trachea was removed, opened longitudinally, and incubated in the fixative for 3 h at room temperature. In a separate study, to deplete circulating granulocytes, cyclophosphamide (100 mg/kg) was injected intraperitoneally 5 days before the experiment. One day before the experiment, a second injection of cyclophosphamide (50 mg/kg) was given, causing a decrease in the peripheral neutrophils from (7.15 + 0.83) x 103 to (0.036 ± 0.005) x 103/mm3 (n = 6; P < 0.001), and the effect of each macrolide (10 mg/kg) on LPS-induced microvascular leakage in neutropenic rats was assessed.To stain myeloperoxidase-containing granulocytes, each tracheal section was incubated for 7 h at 4°C in a solution consisting of 25 mg of 3,3'-diaminobenzidine dissolved in 50 ml of 0.05 M Tris-HCl buffer at pH 7.6 and containing 0.5 ml of Triton X-100 and 0.5 ml of 1% hydrogen peroxide. Tracheal whole mounts were then prepared and neutrophils were counted (8). The magnitude of vascular permeability was assessed by using stereological point counting to determine the areal density of the blood vessels labeled with Monastral blue in the whole mount sections. Data were expressed as means + standard errors of the means. Statistical analysis was performed by using analysis of variance or Newman-Keuls multiple comparison test, and a P value of < 0.05 was considered significant.As shown in Fig. 1,...

Background -Anticholinergic bronchodilator drugs improve lung function in chronic bronchitis but less is known of their effects on the volume and physical properties of sputum in conditions associated with excessive airway secretions. This study examines the effects of the regular use of oxitropium bromide in such patients. Methods -The study was conducted in a parallel, double blind, placebo controlled fashion. Patients were divided into two groups: the first group (n= 17) received oxitropium bromide from a metered dose inhaler (two puffs three times daily; 100 pg/puff) for eight weeks, and the second group (n = 16) received placebo.Lung function was measured as forced expiratory volume in one second (FEVy) and vital capacity. In evaluating airway secretion, daily amount of expectorated sputum, percentage solid composition, viscoelastic properties including elastic modulus and dynamic viscosity, and sputum microbiology were determined. Results -Oxitropium bromide increased FEV1 and decreased the mean (SE) sputum production from 61(4) to 42(3) g/day after treatment, whereas placebo had no effect. Bacterial density and sputum flora were unchanged, but solid composition and elastic modulus increased from 2-52(0-43)% to 3-12 (0 34)%, and 68(12) dyne/ cm2, respectively, in the group taking oxitropium bromide. Conclusions -Regular treatment with oxitropium bromide not only improves airflow limitation but also reduces sputum production, probably through the inhibition of both mucus secretion and water transport, the latter component being predominant.

Nitric oxide (NO) may play a part in pulmonary vascular regulation and bronchomotor control and has been detected in exhaled air. We report the release of NO from airway epithelial cells and its regulation by cyclic adenosine monophosphate (cAMP). To directly measure NO release, a highly specific amperometric sensor for NO made of Pt/Ir alloy coated with a three-layered membrane consisting of KCI, NO-selective resin, and normal silicon resin was developed. Immersion of this sensor in the medium containing canine cultured tracheal epithelium detected baseline levels of NO at 9.6 +/- 1.6 nM (mean +/- SE), which was reduced by NG-nitro-L-arginine methylester (L-NAME) but not by D-NAME. This inhibition was reversed by L-arginine. Addition of isoproterenol, 3-isobutyl-1-methylxanthine, and forskolin caused a rapid increase in NO, an effect that was not altered by Ca(2+)-free medium in the presence of the intracellular Ca2+ chelator BAPTA-AM and the calmodulin antagonist W-7. Bradykinin, ionomycin, and ATP were without effect on NO release. The forskolin-induced NO release was accompanied by intracellular accumulation of cAMP and Ca2+. In contrast, bradykinin increased intracellular Ca2+ but not cAMP levels. Cytochemistry of cultured tracheal epithelium showed a positive staining with NADPH diaphorase activity. These results suggest that airway epithelial cells spontaneously release NO and that the release may be stimulated specifically through cAMP-dependent mechanism.