Anti-inflammatory activity of azithromycin attenuates the effects of lipopolysaccharide administration in mice

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Abstract

Macrolide antibacterials inhibit the production of various cytokines and the migration of inflammatory cells. These anti-inflammatory actions of macrolides may be beneficial in attenuating inflammatory processes involved in bacterial sepsis. Therefore, we investigated the ability of azithromycin to attenuate the deleterious effects of lipopolysaccharide (LPS), in three different LPS-induced inflammatory models. Our results show that azithromycin (10 and 100 mg/kg) significantly attenuated the intraperitoneal LPS-induced increase in plasma TNF-α concentration. It also increased survival rate in a septic shock model in mice challenged with intravenous LPS. Oral treatment with azithromycin (up to 300 mg/kg) was less effective in suppressing neutrophil infiltration into the lungs 24 h after intranasal LPS challenge, possibly because of a slower onset of action or inadequate dosing. In the same model, azithromycin given intraperitoneally significantly improved inflammatory markers (total cell number, neutrophil percentage and MIP-2 concentration) in bronchoalveolar lavage fluid. In conclusion, azithromycin exhibits significant anti-inflammatory properties but the potency of such effects varies depending on the experimental model and route of administration.

Introduction

Macrolides, a family of antibiotics isolated from streptomycetes, are widely used for the treatment of moderate to severe bacterial infections (Zhanel et al., 2001). A growing number of reports indicate that, in addition to anti-microbial properties, macrolides possess a broad spectrum of anti-inflammatory and immunomodulatory effects (reviewed in Culic et al., 2001, Labro, 2004, Tsai and Standiford, 2004). Macrolides accumulate in inflammatory cells, especially neutrophils and macrophages (Gladue et al., 1989, Wildfeuer et al., 1989, Wildfeuer et al., 1996), inhibiting the synthesis of reactive oxygen species and/or secretion of pro-inflammatory cytokines (Culic et al., 2002, Ianaro et al., 2000, Khan et al., 1999, Suzaki et al., 1999, Tamaoki et al., 1999, Terao et al., 2003). Additionally, macrolides are reported to inhibit adhesion molecule expression on epithelial cells, suppressing leukocyte adhesion and infiltration into tissues (Anderson et al., 1996, Culic et al., 2002, Kadota et al., 1993, Sanz et al., 2004, Tamaoki et al., 1995). The most probable mechanism by which macrolides express their anti-inflammatory properties is inhibition of two of the most important transcription factors for the inflammatory response, nuclear factor kappa B (NF-κB) and activator protein 1 (AP-1) (Kikuchi et al., 2002, Okamoto et al., 1994).

As a consequence, anti-inflammatory macrolides are being used in the treatment of various chronic inflammatory diseases, including diffuse panbronchiolitis, cystic fibrosis and chronic sinusitis. In order to achieve a therapeutic effect, they are usually administered for long time periods, several months or even years (Azuma and Kudoh, 2005, Baumann et al., 2004, Pirzada et al., 2003). However, it was reported recently that short-term treatment with azithromycin modulates neutrophil and inflammation markers in chronic obstructive pulmonary disease (Parnham et al., 2005). Therefore, it is possible that even short-term treatment with macrolides could efficiently ameliorate acute inflammatory diseases such as sepsis.

The pathogenesis of sepsis involves a progressive and dynamic expansion of the systemic inflammatory response to bacterial infection (Glauser, 2000). A major factor contributing to sepsis is the shedding of lipopolysaccharide (LPS) from the cell wall of Gram-negative bacteria into the circulation. This pro-inflammatory molecule interacts with a variety of cell types and induces hyperproduction of various cytokines. One of the central cytokines involved in sepsis is tumour necrosis factor alpha (TNF-α), systemic release of which induces increased vascular permeability and disseminated intravascular coagulation, which often leads to a state of shock (Annane et al., 2005). Furthermore, sepsis is associated with the activation and migration of leukocytes into various organs (Annane et al., 2005). The most common event is infiltration of activated neutrophils into lung tissue, inducing acute lung injury (Welbourn and Young, 1992).

As the time course of sepsis is extremely short, especially once the systemic inflammatory response has been initiated, we were interested in whether single oral azithromycin administration to mice could attenuate the deleterious effects of LPS from Gram-negative bacteria. We studied the ability of azithromycin to ameliorate the effects of LPS in three different murine experimental models, mimicking various stages of the pathological cascade in sepsis: LPS-induced plasma TNF-α production, septic shock and pulmonary neutrophilia.

Section snippets

Animals

All studies were performed on male BALB/cJ mice weighing 25–30 g obtained from IFFA CREDO Laboratories, Lyon, France. Mice were kept on wire mesh floors with irradiated maize granulate bedding (Scobis Due, Mucedola, Italy) and maintained under standard laboratory conditions (temperature 22 ± 2 °C, relative humidity 55 ± 10%, approx. 20 air changes per hour, filtered on HEPA 99.97%, artificial lighting with circadian cycle of 12 h). Food (Mucedola, Italy) and tap water were provided ad libitum. Mice

Effect of azithromycin on LPS-induced plasma TNF-α production

We tested the ability of azithromycin to suppress the LPS-induced increase in plasma TNF-α, an important proximal mediator of sepsis syndromes. Prior to administration of LPS to healthy mice, TNF-α was not detectable in plasma. As expected, LPS administration markedly increased plasma concentrations of TNF-α (Fig. 1, Fig. 2). As determined in a preliminary experiment, the peak plasma TNF-α was recorded 90 min after intraperitoneal LPS administration (Fig. 1). Therefore, we limited investigation

Discussion

Earlier investigations in an animal model of sepsis indicated the usefulness of combined drug therapy directed against the bacteria, the circulating endotoxin and the induced cytokines (Cross et al., 1993a). As macrolide antibiotics have a large volume of distribution and achieve relatively low concentrations in sera (Nilsen, 1987), they are not considered to be primary antibacterials for the treatment of infections that are accompanied by a severe sepsis syndrome. Therefore, very few reports

Acknowledgments

This work was supported by PLIVA Research Institute Ltd. The authors wish to thank Ms. M. Horvatinčić, R. Povrženić, M. Škalic, I. Novaković and S. Skender, and Mr. V. Vrban for their excellent technical assistance.

References (39)

  • A. Azuma et al.

    The use of macrolides for treatment of diffuse panbronchiolitis

  • A.M. Badger et al.

    Pharmacological profile of SB 203580, a selective inhibitor of cytokine suppressive binding protein/p38 kinase, in animal models of arthritis, bone resorption, endotoxin shock and immune function

    J. Pharmacol. Exp. Ther.

    (1996)
  • U. Baumann et al.

    Long term azithromycin therapy in cystic fibrosis patients: a study on drug levels and sputum properties

    Can. Respir. J.

    (2004)
  • B. Beutler et al.

    Passive immunization against cachectin/tumor necrosis factor protects mice from lethal effect of endotoxin

    Science

    (1985)
  • G.I. Criqui et al.

    Effects of azithromycin on ozone-induced airway neutrophilia and cytokine release

    Eur. Respir. J.

    (2000)
  • A.S. Cross et al.

    The efficacy of combination immunotherapy in experimental Pseudomonas sepsis

    J. Infect. Dis.

    (1993)
  • A.S. Cross et al.

    Choice of bacteria in animal models of sepsis

    Infect. Immun.

    (1993)
  • E.J. Giamarellos-Bourboulis et al.

    Immunomodulatory clarithromycin treatment of experimental sepsis and acute pyelonephritis caused by multidrug-resistant Pseudomonas aeruginosa

    Antimicrob. Agents Chemother.

    (2004)
  • R.P. Gladue et al.

    In vitro and in vivo uptake of azithromycin (CP-62,993) by phagocytic cells: possible mechanism of delivery and release at sites of infection

    Antimicrob. Agents Chemother.

    (1989)
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