In vitro effects of clarithromycin on human polymorphonuclear leukocyte functions

Effect of levofloxacin on neutrophilic airway inflammation in stable COPD: a randomized, double-blind, placebo-controlled trial

Rationale

Airway inflammation persists after smoking cessation in established chronic obstructive pulmonary disease (COPD), suggesting that other factors drive the airway inflammatory response.

Objectives

We tested the hypothesis that high levels of bacterial colonization are associated with increased levels of neutrophilic airway inflammation in stable COPD by examining the cross-sectional relationship between these measurements and by conducting a randomized, double-blind, placebo-controlled study of the effect of levofloxacin in patients with stable COPD.

Methods

Patients were randomized to receive either levofloxacin 500 mg daily or placebo for 7 days and underwent sputum induction for a differential cell count and quantitative bacterial analysis at baseline and at days 7, 14, and 28.

Results

Sputum percentage neutrophil count correlated with airway bacterial load at baseline (r=0.56; P=0.003). Levofloxacin reduced bacterial load compared with placebo by 4.9-fold (95% confidence interval, 1.4–25.7; P=0.02) at day 7 but had no effect at any point on any marker of neutrophilic airway inflammation. In patients with a baseline bacterial load of more than 10⁶ cfu/mL, levofloxacin treatment was associated with a 26.5% (95% confidence interval, 1.8%–51.3%; P=0.04) greater reduction in the percentage neutrophil count compared with placebo at day 7. Change in percentage neutrophil count correlated significantly with baseline airway bacterial load and change in airway bacterial load.

Conclusion

In stable COPD, levofloxacin treatment causes a short-term reduction in bacterial load. This is associated with a reduction in neutrophilic airway inflammation in patients with high bacterial loads. Further studies are required to investigate whether this effect is clinically advantageous.

WBC count and functional changes induced by co-administration of clofazimine and clarithromycin, in single and multiple doses, in Wistar rats

Clofazimine and clarithromycin are used to treat leprosy and infections caused by Mycobacterium avium complex. Little data on the toxicity of co-administration of these two drugs are available. Here we evaluated the potential adverse effects of polytherapy with these two drugs in male Wistar rats by determining WBCs counts and other blood cell counts, neutrophilic phagocytosis, and burst oxidative, by flow cytometry. We observed an increase in WBCs, in multiple-dose regimens, and in polymorphonuclear cells, in both single- clarithromycin only and multiple dose regimens. We also observed a reduction in mononuclear cell counts in single and multiple doses. The drugs seem to reverse the mononuclear and polymorphonuclear cell ratio. An increase in oxidative burst was observed in animals treated with the drugs administered either individually or combined. In conclusion, clofazimine and clarithromycin change WBCs counts. Our results may contribute for a better understanding of the mechanisms related to the effects of co-administrating the two drugs.

Synthesis, structural characterization and influence on the phagocytic activity of human neutrophils of thiazoline and thiazine derivative ligands and their zinc(II) complexes

The zinc(II) complexes dichloro[2-(3,4-dichlorophenyl)imino-kappaN-(2-thiazolin-kappaN-2-yl)thiazolidine]zinc(II) (1) and dichloro[2-(3,4-dichlorophenyl)imino-kappaN-(4H-5,6-dihydro-1,3-thiazin-kappaN-2-yl)tetrahydrothiazine]zinc(II) (2) have been isolated and characterized in the solid state by X-ray diffraction, elemental analysis and IR spectra. In both complexes, the environment around the zinc(II) ion may be described as a distorted tetrahedral geometry, with the metallic atom coordinated to two chlorine atoms [Zn-Cl(1)=2.218(1)A; Zn-Cl(2)=2.221(1)A], one imino nitrogen [Zn-N(3)=2.042(2)A] and one thiazoline nitrogen [Zn-N(1)=2.022(2)A] in complex 1 and to two chlorine atoms [Zn-Cl(1)=2.216(1)A; Zn-Cl(2)=2.192(1)A], one imino nitrogen [Zn-N(3)=2.045(2)A] and one thiazine nitrogen [Zn-N(1)=2.039(2)A] in complex 2. In addition, we also report in this study the crystal structure of the 2-(3,4-dichlorophenyl)imino-N-(2-thiazolin-2-yl)thiazolidine (TdTn) ligand as well as the synthesis and characterization by X-ray diffraction, (1)H and (13)C NMR spectra, elemental analysis, IR and electronic spectra of the 2-(3,4-dichlorophenyl)imino-N-(4H-5,6-dihydro-1,3-thiazin-2-yl)tetrahydrothiazine (TzTz) ligand. Besides, we study the phagocytic function in humans neutrophils treated with each complex and ligand aforementioned.

Lung perfusion with clarithromycin ameliorates lung function after cardiopulmonary bypass

BACKGROUND

Macrolides antibiotics may affect neutrophil functions that correlate with the inflammation induced by cardiopulmonary bypass. Our study observed the protective effect of clarithromycin on inflammatory lung injury after cardiopulmonary bypass.

METHODS

Twelve adult sheep were randomly divided into two groups. After cardiopulmonary bypass was established, the lung was perfused through the pulmonary artery with either dextran solution (30 mL/kg) in the control group (n = 6) or dextran solution added to clarithromycin (10 mg/kg) in the experimental group (n = 6). Bypass was withdrawn after 90 minutes. Pulmonary function was determined and inflammatory factors were analyzed. Apoptotic neutrophils in the lung were assayed and lung biopsies were also performed.

RESULTS

Pulmonary vascular resistance (102.2 +/- 14.0 dyne.s.cm(-5)) was lower in the experimental group compared with the control group (202.6 +/- 47.3 dyne.s.cm(-5), p < 0.01) whereas the oxygen index was higher in the experimental group (p < 0.05). Plasma myeloperoxidase in the experimental group (0.015 +/- 0.006 U/L) was lower than that in the control group (0.029 +/- 0.007 U/L, p < 0.01). Plasma interlukin-8 (0.18 +/- 0.04 ug/L) and tumor necrosis factor (1.00 +/- 0.13 ug/L) in the experimental group were lower than in the control group (0.39 +/- 0.09 ug/L, 1.55 +/- 0.35 ug/L, p < 0.01). Histologic analyses showed intra-alveolar hemorrhage and neutrophil accumulation in the control group, whereas there were no significant changes in the experimental group. The apoptosis rate of accumulated neutrophils was significantly lower in the control group (p < 0.01).

CONCLUSIONS

Lung perfusion with hypothermic protective solution containing clarithromycin distinctly inhibits inflammatory responses caused by cardiopulmonary bypass and ameliorates lung function.

Effects of clarithromycin on inflammatory cell mediator release and survival

BACKGROUND

Clarithromycin exhibits anti-inflammatory as well as antimicrobial activity, leading to decreased symptoms of asthma and chronic sinusitis. The mode of anti-inflammatory effects of clarithromycin on inflammatory cells is not well understood. We hypothesized that clarithromycin inhibits inflammatory cell mediator release and survival.

METHODS

We investigated the effects of this drug on survival and mediator release from mast cells, eosinophils and neutrophils.

RESULTS

Human eosinophil and neutrophil respiratory burst was inhibited by up to 54% after 1-2 h pretreatment with 100 microg/ml clarithromycin. Similar doses of erythromycin did not affect respiratory burst responses in these cells. Clarithromycin at doses of up to 100 microg/ml had no effect on granule-derived mediators released from mast cells and neutrophils. However, we found that clarithromycin (100 microg/ml) induced cell death in mast cells and eosinophils after 16-48 h incubation.

CONCLUSION

Clarithromycin inhibited inflammatory cell mediator release and survival, which may enhance its ability to reduce the symptoms of chronic sinusitis and asthma.

Effect of antituberculous drugs on human polymorphonuclear leukocyte functions in vitro

The aim of the study was to investigate antituberculous drugs effects on polymorphonuclear leukocyte (PMN) functions (phagocytic activity and intracellular killing activity) in vitro. PMNs obtained from healthy volunteers were incubated with antituberculous drugs (isoniazid [INH], rifampin [RIF], pyrazinamide [PZA], ethambutol [EMB], streptomycin [S], amikacin [A], ofloxacin [OFLX], prothionamide [PTH] and cycloserine [CyC]) and different combinations at therapeutic serum concentrations. Phagocytic activity of PMNs was significantly increased when compared with controls by PTH (p<0.001), A (p<0.001), OFLX (p<0.001), INH+RIF+S combination (p<0.01), A+OFLX combination (p<0.05), A+OFLX+CyC combination (p<0.01) and A+OFLX+CyC+PTH+EMB combination (p<0.01). Intracellular killing activity of PMNs was significantly increased by OFLX when compared with the control (p<0.05). No significant difference was observed in functions of PMN for other drugs when compared with control (p>0.05). Functions of PMN were significantly increased by OFLX when compared with A+OFLX combination (p<0.05). Phagocytic activity of PMNs was significantly increased by A+OFLX+CyC combination and A+OFLX+CyC+PTH+EMB combination when compared with A+OFLX+CyC+PTH combination and A+OFLX+CyC+PTH+PZA combination (p<0.05). No significant difference was found in functions of PMN between the other groups (p>0.05). In conclusion, some antituberculous drugs alone or in combination enhanced PMN functions, although in combination no additive or synergistic effects were detected. Moreover, none of the antituberculous drugs alone or in combination significantly decreased PMN functions. The drugs having adverse effects on immune functions would better be replaced with equally effective drugs or drug combinations having positive effects on PMN functions.

The Effect of Clarithromycin on Inflammatory Markers in Chronic Obstructive Pulmonary Disease: Preliminary Data

BACKGROUND:

Clarithromycin is an antimicrobial agent that can be used for treatment of chronic obstructive pulmonary disease (COPD) exacerbations with bronchodilator therapy. However, it has also been shown that clarithromycin has antiinflammatory effects by the inhibition of cytokine production.

OBJECTIVE:

To evaluate the antiinflammatory effect of clarithromycin on serum and sputum interleukin-8 (IL-8), tumor necrosis factor-α (TNF-α), and leukotriene B4 levels in patients with COPD.

METHODS:

Thirty men with mild to moderate COPD were enrolled in this prospective, single-center, double-blind, placebo-controlled study. None of the patients was receiving systemic or inhaled corticosteroids during the study. Subjects received either clarithromycin or placebo for 14 days. Before and after this treatment period, spirometric tests and arterial blood gas analysis were performed, blood was drawn for measurement of serum inflammatory markers, and sputum was induced.

RESULTS:

There were no statistically significant differences in baseline clinical or laboratory parameters between the groups. After the treatment, the induced sputum total cell counts, and IL-8 and TNF-α levels decreased significantly in the clarithromycin group compared with pretreatment levels (mean ± SD IL-8 1606 ± 367.3 vs 882 ± 143.6 pg/mL, p = 0.001; TNF-α 638.2 ± 287.5 vs 390 ± 235 pg/mL, p = 0.001). Similarly, decreases in serum inflammatory markers were found in the clarithromycin group while there was no significant change in the placebo group.

CONCLUSIONS:

This study demonstrated that the decrease in IL-8 and TNF-α levels might be related to the antiinflammatory effect of clarithromycin. Thus, we suggest that the use of clarithromycin in COPD exacerbations may either treat the infection or help control the inflammation. Future studies are needed to determine the clinical significance of these findings.

The effects of macrolides on inflammatory cells

Bronchial epithelial damage and mucus hypersecretion are characteristic features of chronic airway inflammation that can impair mucociliary clearance and can cause recurrent or persistent respiratory infection. In response to chemoattractants produced by damaged or inflamed tissue, neutrophils move through sequential steps of recruitment, migration, accumulation, and adhesion to endothelial and bronchial epithelial cells. Neutrophils engage in bacteriocidal activity by phagocytosis, release of lysosomal enzymes, and generation of reactive oxygen species, and they synthesize and release proinflammatory cytokines. Data confirm that many macrolide antibiotics have nonbactericidal properties that include inhibiting inflammatory cell chemotaxis, cytokine synthesis, adhesion molecule expression, and reactive oxygen species production. Macrolides also can decrease airway mucus hypersecretion in patients with diffuse panbronchiolitis, chronic sinusitis, and chronic bronchitis. Macrolides accumulate in neutrophils and macrophages at significantly higher concentrations than in extracellular fluid. This article discusses the action of macrolides on neutrophil accumulation, immune complex-mediated production of nitric oxide, mucin production, and the expanded therapeutic role of macrolides as biological response modifiers.

Effect of montelukast on polymorphonuclear leukocyte functions in asthmatic patients

Leukotriene receptor antagonists are being used widely in the treatment of bronchial asthma. They have been shown to possess anti-inflammatory properties, but there is no sufficient data about their effects on polymorphonuclear leukocyte functions. The aim of this study was to investigate the effects of montelukast, a specific cysteinyl leukotriene-1 receptor antagonist, on human polymorphonuclear leukocyte (PMN) functions (phagocytic and intracellular killing activity) in asthmatic patients. Fifteen mild to moderate asthmatic patients were included in the study. They were treated with montelukast (10 mg/day per os) in addition to their previous medications for 2 weeks. Whole blood samples of patients were taken before and after this treatment period. Phagocytic activities and intracellular killing activities of polymorphonuclear leukocytes isolated from whole blood samples were tested by using appropriate technics. Phagocytic and intracellular killing activities of PMNs were significantly increased (p<0.001, p<0.05) by montelukast compared to those before treatment. These results show that montelukast has an enhancing effect on PMN functions in asthmatic patients.

In-vitro anti-inflammatory and immunomodulatory effects of grepafloxacin in zymogen A- or Staphylococcus aureus-stimulated human THP-1 monocytes

The effects of grepafloxacin on the release of cytokines, chemical mediators, hydrolytic enzyme activities, and lipoxygenation in zymogen A- or Staphylococcus aureus-stimulated human THP-1 monocytes were evaluated. Initially, consistent with stimulation of phagocytic mechanisms of the monocytes, increases in cyclic adenosine monophosphate (cAMP) release, nitric oxide [NO] release, and hydrogen peroxide [H(2)O(2)] release, with a small decrease in cellular pH, occurred within 2 h. Enzymatic activities associated with oxygen burst of phagocytic cells (e.g., protein kinase C and nicotinamide adenine dinucleotide phosphate, reduced (NADPH) oxidase) were elevated, suggesting that monocytes attempted to destroy the invading organism through an innate phagocytic cidal immunologic mechanism. After 1-2 h of exposure to grepafloxacin, the oxygen burst and the release of proinflammatory cytokines and chemical mediators were suppressed. After 4 h, suppression of n-acetyl glucosaminidase (NAG) and cathepsin D activities and lipid peroxidation occurred, suppressing the pathogen-induced spread of infection and inflammation. Release of tumor necrosis factor (TNFalpha), interleukin (IL)-1, IL-6, and IL-8 was inhibited by grepafloxacin in a concentration-dependent manner, suggesting a reduction in the acute-phase inflammatory responses initiated by cytokine release from monocytes. Later, S. aureus were killed through inhibition of DNA synthesis, consistent with a bacteriostatic effect. Drug action against invading organisms appears to occur through multiple processes. Modulation of the innate immune system occurs within the first hour, causing the activation of cytokines, chemical mediators, and hydrolytic enzymes. A second phase between 2-4 h appears to involve the suppression of cellular components involved in inflammation and the spread of the infection. The third response, an apparent bacteriostatic inhibition of DNA synthesis, causes bacterial death.

Disposition and intracellular activity of azithromycin in human THP-1 acute monocytes

Uptake of [14C]-azithromycin into THP-1 human monocytes was determined at pH 7.4, 6.8 or 5.5 over 4-log antibiotic concentrations for 24 h under a number of conditions. Stimulation of cells was with bacteria, latex beads, lipopolysaccharide (LPS), or zymogen A. Subcellular organelle disposition was determined after isolation by ultracentrifugation or sucrose gradients. Hydrolytic enzyme activities and mediators of intracellular inflammation (IL-1, IL-6, IL-8, and TNFalpha) were assessed. Azithromycin uptake into human THP-1 monocytes was initially linear achieving approximately 2% of the extracellular concentration. At pH 7.4, uptake was both passive- and carrier-mediated, but as the pH became more acidic, the uptake was exclusively passive. The intracellular concentration was not pH-dependent over 24 h. Uptake was dependent upon temperature but not the presence of foetal calf serum. Intracellular disposition in zymogen A-stimulated and unstimulated cells was throughout all compartments of the cell, but was higher in the nucleus and cell sap. Phagosomes of stimulated cells contained higher level of the antibiotic. Efflux from THP-1 monocytes was complete between 3 and 4 h. After 1 h treatment with zymogen A, THP-1 monocytes demonstrated an increase in intracellular acidity, protein kinase C, SOD and NAG activities, and NO, H(2)O(2), TNFalpha and IL-1 release over the 1st h. After 2-4 h the pH became alkaline, activities of NADPH reductase, NAG and cathepsin were reduced, and the release of NO, H(2)O(2), TNFalpha and IL-6 were suppressed. Protein synthesis and killing of the bacteria was evident in bacteria kept in monocyte-free medium and those phagocytized by the THP-1 monocytes moderately at 2 h, but more significantly at 24 h. The early killing of the bacteria appears to be a cidal mechanism whereas later, a standard bacteriostatic mechanism was evident. Nevertheless, suppression of these chemical mediators and hydrolytic enzyme activities would reduce the infection and the spread to adjacent areas.