Effects of erythromycin on experimental extrinsic allergic alveolitis

Long-term macrolides in diffuse interstitial lung diseases

In the present review we provide currently available evidence for the use of macrolides in the treatment of diffuse interstitial lung diseases (ILDs). Up to now, research on macrolides has mainly focused on three areas. First, macrolides have shown some promising results in cellular models and case reports as antifibrotic agents, by promoting autophagy and clearance of intracellular protein aggregates and acting as regulators of surfactant homeostasis. Secondly, macrolides have an immunomodulatory effect, which has been applied in some organising pneumonia cases. In particular, macrolides have been tested in association with systemic corticosteroids as steroid-sparing agents and alone as either first-line agents in mild cases or second-line agents where steroids were poorly tolerated or had failed. Thirdly, a recent area of research concerns the possible role of macrolides as modulators of lung microbiota and the host–microbiota interaction. This function has been particularly studied in idiopathic pulmonary fibrosis patients, in whom changes in microbiota have been proved to be associated with disease progression. However, the lack of high-quality studies makes the application of macrolide therapy in ILDs a field in which research should be conducted on a large scale.

Combination of Erythromycin and Curcumin Alleviates Staphylococcus aureus Induced Osteomyelitis in Rats

Osteomyelitis is commonly caused by Staphylococcus aureus. Both erythromycin and curcumin can suppress S. aureus growth, but their roles in osteomyelitis are barely studied. We aim to explore the activities of erythromycin and curcumin against chronical osteomyelitis induced by methicillin-resistant S. aureus (MRSA). Chronicle implant-induced osteomyelitis was established by MRSA infection in male Wistar rats. Four weeks after bacterial inoculation, rats received no treatment, erythromycin monotherapy, curcumin monotherapy, or erythromycin plus curcumin twice daily for 2 weeks. Bacterial levels, bone infection status, inflammatory signals and side effects were evaluated. Rats tolerated all treatments well, with no death or side effects such as, diarrhea and weight loss. Two days after treatment completion, erythromycin monotherapy did not suppress bacterial growth and had no effect in bone infection, although it reduced serum pro-inflammatory cytokines tumor necrosis factor (TNF)-α and interleukin (IL)-6. Curcumin monotherapy slightly suppressed bacterial growth, alleviated bone infection and reduced TNF-α and IL-6. Erythromycin and curcumin combined treatment markedly suppressed bacterial growth, substantially alleviated bone infection and reduced TNF-α and IL-6. Combination of erythromycin and curcumin lead a much stronger efficiency against MRSA induced osteomyelitis in rats than monotherapy. Our study suggests that erythromycin and curcumin could be a new combination for treating MRSA induced osteomyelitis.

Management of hypersensivity pneumonitis

Hypersensitivity pneumonitis (HP) is an interstitial lung disease due to a combined type III and IV reaction with a granulomatous inflammation, caused by cytotoxic delayed hypersensitivity lymphocytes, in a Th1/Th17 milieu, chaperoned by a deficient suppressor function of T regulatory cells. Skewing toward a Th2 phenotype is reported for chronic HP. Phenotypic expression and severity depends on environmental and/or host genetic and immune co-factors. The wide spectrum of causative antigens is continuously up-dated with new sources of airborne organic particles and drug-induced HP. The diagnosis requires a detailed history, measurement of environmental exposure, pulmonary function tests, imaging, detection of serum specific antibodies, broncho-alveolar lavage, antigen-induced lymphocyte proliferation, environmental or laboratory-controlled inhalation challenge and lung biopsy. Complete antigen avoidance is the best therapeutic measure, although very difficult to achieve in some cases. Systemic steroids are of value for subacute and chronic forms of HP, but do not influence long term outcome. Manipulation of the immune response in HP holds future promise.

Where asthma and hypersensitivity pneumonitis meet and differ: noneosinophilic severe asthma

Asthma is a type-I allergic airway disease characterized by Th(2) cells and IgE. Episodes of bronchial inflammation, eosinophilic in nature and promoting bronchoconstriction, may become chronic and lead to persistent respiratory symptoms and irreversible structural airway changes. Representative mostly of mild to moderate asthma, this clinical definition fails to account for the atypical and often more severe phenotype found in a considerable proportion of asthmatics who have increased neutrophil cell counts in the airways as a distinguishing trait. Neutrophilic inflammation is a hallmark of another type of allergic airway pathology, hypersensitivity pneumonitis. Considered as an immune counterpart of asthma, hypersensitivity pneumonitis is a prototypical type-III allergic inflammatory reaction involving the alveoli and lung interstitium, steered by Th(1) cells and IgG and, in its chronic form, accompanied by fibrosis. Although pathologically very different and commonly approached as separate disorders, as discussed in this review, clinical studies as well as data from animal models reveal undeniable parallels between both airway diseases. Danger signaling elicited by the allergenic agent or by accompanying microbial patterns emerges as critical in enabling immune sensitization and in determining the type of sensitization and ensuing allergic disease. On this basis, we propose that asthma allergens cause severe noneosinophilic asthma because of sensitization in the presence of hypersensitivity pneumonitis-promoting danger signaling.

Erythromycin ameliorates renal injury via anti-inflammatory effects in experimental diabetic rats

AIMS/HYPOTHESIS

Recent studies have shown that the inflammatory process is involved in the pathogenesis of diabetic nephropathy. Fourteen-membered ring macrolides, including erythromycin, have anti-inflammatory, as well as antibacterial effects. The aim of this study was to investigate the renoprotective effects of erythromycin in streptozotocin (STZ)-induced diabetic rats.

METHODS

STZ-induced diabetic rats were treated orally with erythromycin (5 mg/kg body weight) or vehicle every day for 8 weeks. To evaluate the effect of erythromycin treatment, we measured urinary albumin excretion, and examined the following in the kidney: histological changes, the expression of intercellular adhesion molecule-1 (ICAM-1), macrophage infiltration, and nuclear factor-kappa B (NF-kappaB) activity.

RESULTS

Erythromycin significantly reduced urinary albumin excretion without affecting blood glucose levels and blood pressure. Erythromycin also attenuated glomerular hypertrophy, mesangial expansion, macrophage infiltration and ICAM-1 expression in renal tissues. The expression of the gene encoding TGFB1 (also known as TGF-beta1), type IV collagen protein production and NF-kappaB activity in renal tissues were increased in diabetic rats and reduced by erythromycin treatment.

CONCLUSIONS/INTERPRETATION

Erythromycin prevented renal injuries without changes of blood glucose levels and blood pressure in experimental diabetic rats. These results suggest that the renoprotective effects of erythromycin are based on its anti-inflammatory effect via suppression of NF-kappaB activation. Modulation of microinflammation with erythromycin may provide a new approach for diabetic nephropathy.

Erythromycin exerts in vivo anti-inflammatory activity downregulating cell adhesion molecule expression

1. Macrolides have long been used as anti-bacterial agents; however, there is some evidence that may exert anti-inflammatory activity. Therefore, erythromycin was used to characterize the mechanisms involved in their in vivo anti-inflammatory activity. 2. Erythromycin pretreatment (30 mg kg(-1) day(-1) for 1 week) reduced the lipopolysaccharide (LPS; intratracheal, 0.4 mg kg(-1))-induced increase in neutrophil count and elastase activity in the bronchoalveolar lavage fluid (BALF) and lung tissue myeloperoxidase activity, but failed to decrease tumor necrosis factor-alpha and macrophage-inflammatory protein-2 augmented levels in BALF. Erythromycin pretreatment also prevented lung P-selectin, E-selectin, intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) mRNA upregulation in response to airway challenge with LPS. 3. Mesentery superfusion with LPS (1 mug ml(-1)) induced a significant increase in leukocyte-endothelial cell interactions at 60 min. Erythromycin pretreatment abolished the increases in these parameters. 4. LPS exposure of the mesentery for 4 h caused a significant increase in leukocyte rolling flux, adhesion and emigration, which were inhibited by erythromycin by 100, 93 and 95%, respectively. 5. Immunohistochemical analysis showed that LPS exposure of the mesentery for 4 h caused a significant enhancement in P-selectin, E-selectin, ICAM-1 and VCAM-1 expression that was downregulated by erythromycin pretreatment. 6. Flow cytometry analysis indicated that erythromycin pretreatment inhibited LPS-induced CD11b augmented expression in rat neutrophils. 7. In conclusion, erythromycin inhibits leukocyte recruitment in the lung and this effect appears mediated through downregulation of CAM expression. Therefore, macrolides may be useful in the control of neutrophilic pulmonary diseases.

Macrolide antibiotics: current and future uses

After a long history of anti-infective therapeutic use, macrolide antibiotics have not yet given up all their secrets. Interest in their therapeutic potential in inflammatory diseases (possibly including non-infectious diseases) has generated abundant fundamental research and therapeutic trials worldwide. The main question regarding the future prospects of this class of drugs is whether some macrolides are beneficial in such settings because they modulate host inflammatory responses (and cellular targets) or rather because they eliminate a latent, unidentified pathogen which triggers chronic inflammation. However, no clearcut results have yet been obtained.

The Effect of Oral Clarithromycin on Bronchial Airway Inflammation in Moderate-to-Severe Stable COPD

INTRODUCTION

COPD is characterized by bronchial neutrophilic inflammation. Clarithromycin is a macrolide antibiotic that has antibacterial and anti-inflammatory properties. Macrolide antibiotics have been shown to improve airway inflammation in diffuse pan-bronchiolitis but their role in COPD is undetermined. The aim of the study was to determine if 3 months of therapy with modified-release oral clarithromycin (Klaricid XL) 500 mg/day reduced bronchial airway inflammation in patients with moderate-to-severe stable COPD compared with placebo.

METHODS

A prospective, double-blind controlled trial randomized patients with moderate-to-severe stable COPD to 3 months' therapy with oral modified-release clarithromycin 500 mg/day or placebo. Patients underwent saline sputum induction before and after treatment with clarithromycin. The effects of clarithromycin on sputum total cell and neutrophil counts, supernatant interleukin-8 (IL-8), leukotriene B(4) (LTB(4)), tumor necrosis factor (TNF)-alpha, neutrophil elastase (NE), and neutrophil chemotaxis were assessed in comparison with placebo.

RESULTS

Of a total of 67 patients included in the trial, 31 were treated with clarithromycin and 36 with placebo. The groups were similar in age, body mass index, history of smoking, and spirometry. Of 60 evaluable patients, 26 and 34 completed 3 months' therapy with clarithromycin and placebo, respectively. Clarithromycin had no significant effect on sputum total cell count, neutrophil count, IL-8, LTB(4), TNFalpha levels or neutrophil elastase. However, clarithromycin did cause a small reduction in the neutrophil differential (p = 0.04 relative to placebo) and neutrophil chemotaxis (p = 0.058 relative to placebo).

CONCLUSIONS

Oral clarithromycin 500 mg/day administered for 3 months had no significant effect on sputum neutrophil numbers or cytokine levels in patients with moderate-to-severe stable COPD. However, clarithromycin did cause a small reduction in the neutrophil differential and neutrophil chemotaxis. Further studies may be warranted to determine the clinical significance of these findings.

Severe erythema nodosum due to Behçet's disease responsive to erythromycin

A patient with severe erythema nodosum due to Behçet's disease is reported on here. Erythema nodosum lesions did not respond to classical treatments; however, they cleared after erythromycin treatment, which was prescribed for the treatment of coincidental erythrasma. Erythromycin treatment appears to be an effective treatment option in erythema nodosum. The hypothetical anti-inflammatory effects of erythromycin, besides its antibiotic properties, are reviewed and discussed to explain such a clinical improvement.

[Attenuated mRNA induction of molecules associated with neutrophil migration by 14-membered ring macrolides inhibits bleomycin induced acute lung injury in mice]

BACKGROUND

Although the pathogeneses of interstitial pneumonia are not well understood, it has been reported that inflammatory cells, especially neutrophils, and their injurious substances play important roles in the progression of interstitial pneumonia. Erythromycin and other 14-membered ring macrolides (14-MRMLs) have been reported to inhibit chronic airway inflammation by mechanisms of anti-neutrophil and several other anti-inflammatory activities. The present study was undertaken to investigate the effects and mechanisms of 14-MRMLs (erythromycin: EM; clarithromycin: CAM; roxithromycin: RXM) on an experimental model of bleomycin (BLM) -induced acute lung injury in mice.

METHODS

BLM was administered intravenously to ICR mice. For the evaluation of early-phase inflammation, cell populations in broncho-alveolar lavage fluid (BALF) and induction of mRNA of adhesion molecules (E-selectin, P-selectin, ICAM-1, VCAM-1) and TNF-alpha tested by RT-PCR in lung tissues were examined at 0 to 13 days after BLM. These parameters were also compared with those of the control (NS alone), 14-MRMLs-untreated (BLM alone) and-pre-treated (BLM+pre 14-MRMLs) groups.

RESULTS

The number of neutrophils, macrophages, and lymphocytes significantly increased in BAL. Neutrophils especially increased with two peaks after BLM administration. 14-MRMLs significantly inhibited both peaks of neutrophil. The increase in number of macrophages in BALF was significantly attenuated by EM and RXM, and slightly attenuated by CAM. Number of lymphocytes in BALF was significantly attenuated by EM and CAM, and slightly attenuated by RXM. Changes in mRNA expression of E-selectin, P-selectin, ICAM-1, VCAM-1, and TNF-alpha were associated with the number of neutrophils migrating into the airspace. 14-MRMLs clearly inhibited the induction of VCAM-1 mRNA, and tended to attenuate the induction of ICAM-1 and TNF-alpha mRNA, but did not inhibit the induction of E-selectin and P-selectin mRNA.

DISCUSSION

These findings show that 14-MRMLs clearly attenuated the expression of VCAM-1mRNA, and tended to attenuate the induction of ICAM-1 and TNF-alpha mRNA, and subsequently inhibited leucocyte, especially neutrophil migration into the airspace during the early phase of BLM-induced lung injury and finally inhibited lung fibrosis. This might be one potent mechanism of the anti-inflammatory effects of 14-MRMLs in BLM-induced acute lung injury. The findings suggest that prophylactic administration of 14-MRMLs may be clinically efficacious in preventing acute exacerbation of interstitial pneumonia and acute lung injury.

Anti-inflammatory capabilities of macrolides

Macrolide antibiotics play a significant role in clinical practise due not only to their antibacterial activity, but also to their accompanying anti-inflammatory effect that is independent of their antibiotic action. Several studies reported in literature show that macrolides affect several inflammatory processes, such as migration of neutrophils, the oxidative burst in phagocytes and production of pro-inflammatory cytokines, although the precise mechanisms are not clear. They also inhibit eosinophilic inflammation and may be useful in the treatment of patients with steroid-dependent asthma. Macrolides are also effective in diffuse panbronchiolitis, chronic sinusitis and inflammatory skin diseases.

Effects of roxithromycin on adhesion molecules expressed on endothelial cells of the dermal microvasculature

The objective of the study was to investigate the pharmacological action of roxithromycin, an oral macrolide antibiotic. The effects of roxithromycin on the cytokine-induced expression of endothelial leukocyte adhesion molecule (E-selectin) and intracellular adhesion molecule (ICAM)-1 on endothelial cells of the dermal microvasculature were investigated in vitro using flow cytometry. Roxithromycin at a concentration of 0.5 microgram/ml, which is lower than the therapeutic plasma concentration (ordinary daily dose, 150-300 mg), significantly inhibited the expression of E-selectin and ICAM-1 on endothelial cells of the dermal microvasculature induced by tumour necrosis factor-alpha. We conclude that roxithromycin may exert its anti-inflammatory action by inhibition of the in vivo expression of adhesion molecules on dermal microvascular endothelial cells.

Clarithromycin inhibits NF-kappaB activation in human peripheral blood mononuclear cells and pulmonary epithelial cells

Macrolide antibiotics modulate the production of proinflammatory cytokines in vivo and in vitro. Transcription of the genes for these proinflammatory cytokines is regulated by nuclear factor kappaB (NF-kappaB). We examined whether or not clarithromycin inhibits the activation of NF-kappaB induced by tumor necrosis factor alpha (TNF-alpha) or staphylococcal enterotoxin A (SEA) in human monocytic U-937 cells, a T-cell line (Jurkat), a pulmonary epithelial cell line (A549), and peripheral blood mononuclear cells (PBMC). Flow cytometry revealed that clarithromycin suppresses NF-kappaB activation induced by TNF-alpha in U-937 and Jurkat cells in a concentration-related manner. Western blot analysis also demonstrated that clarithromycin inhibits NF-kappaB activation induced by TNF-alpha in U-937, Jurkat, and A549 cells and PBMC and by SEA in PBMC. Western blot analysis of cytoplasmic extracts of A549 cells revealed that this inhibition is not linked to preservation of expression of the IkappaBalpha protein. The chloramphenicol acetyltransferase assay indicated that NF-kappaB-dependent reporter gene expression is suppressed in U-937 cells pretreated with clarithromycin. These findings are consistent with the idea that clarithromycin suppresses the production of proinflammatory cytokines via inhibition of NF-kappaB activation.

A new look at hypersensitivity pneumonitis

Hypersensitivity pneumonitis is an immunologically induced lung disease. Although both immune complex-mediated immune response and T cell-mediated immune response are involved in the pathogenesis of the disease, recent studies show the latter mechanism to be more important. As for T cell-mediated immune response, Th1/Th2 and Tc1/Tc2 cytokines produced by CD4+ and CD8+ T cells play important roles in the development of granulomatous inflammation in the lung, a pathologically characteristic feature of the disease. The critical distinction between CD4+ and CD8+ T cells pertains to recognition of antigens presented by different major histocompatibility complex molecules. Serum levels of KL-6 and soluble intercellular adhesion molecule-1 in patients with HP are useful markers of the disease activity. The chronic form of HP can be difficult to diagnose, and provocation testing is helpful. Erythromycin might be useful for anti-inflammatory therapy.