Differential effects of three antibiotics on T helper cell cytokine expression

The role of macrolides in severe community-acquired pneumonia and the potential impact of macrolide-resistant Mycoplamsa pneumoniae

PURPOSE OF REVIEW

Define the utility of adjunctive macrolide therapy in patients with more severe forms of community-acquired pneumonia (CAP).

RECENT FINDINGS

Guidelines recommend adjunctive macrolide therapy as an option for patients with CAP, admitted to the hospital. A large data set collected both retrospectively and prospectively, including several recent randomized controlled trials (RCTs) have shown that adjunctive macrolide therapy can reduce mortality and improve outcomes in patients with severe CAP, more effectively than other alternative therapies. This effect appears to be most evident in those with severe illness and appears to be independent of direct antimicrobial effects and may be a result of the immunomodulatory properties of macrolides. A recent RCT, the ACCESS study, showed a clinical benefit of macrolides in severe CAP patients, but this may have been the result of a reversal of infection-related immunoparalysis. Macrolides appear to be valuable for patients with more severe CAP, but their therapeutic value is being challenged by the recent emergence of macrolide-resistant Mycoplasma pneumoniae; however, the optimal therapy for this pathogen still needs to be defined.

SUMMARY

New evidence has further advanced the role of macrolides as preferred adjunctive therapy for patients with severe CAP.

Differences in nature killer cell response and interference with mitochondrial DNA induced apoptosis in moxifloxacin environment

OBJECTIVES

As antibiotics become more prevalent, accuracy and safety are critical. Moxifloxacin (MXF) have been reported to have immunomodulatory effects on a variety of immune cells and even anti-proliferative and pro-apoptotic effects, but the mechanism of action is not fully clear.

METHODS

Peripheral blood mononuclear cells (PBMC) from experimental groups of healthy adults (n = 3) were treated with MXF (10ug/ml) in vitro for 24 h. Single-cell sequencing was performed to investigate differences in the response of each immune cell to MXF. Flow cytometry determined differential gene expression in subsets of most damaged NK cells. Pseudo-time analysis identified drivers that influence MXF-stimulated cell differentiation. Detection of mitochondrial DNA and its involvement in the mitochondrial respiratory chain pathway clarifies the origin of MXF-induced stress injury.

RESULTS

Moxifloxacin-environmental NK cells are markedly reduced: a new subset of NK cells emerges, and immediate-early-response genes in this subset indicate the presence of an early activation response. The inhibitory receptor-dominant subset shows enhanced activation, leading to increased expression of cytokines and chemokines. The near-mature subset showed greater cytotoxicity and the most pronounced cellular damage. CD56bright cells responded by antagonizing the regulation of activation and inhibitory signals, demonstrating a strong cleavage capacity. The severe depletion of mitochondrial genes was focused on apoptosis induced by the mitochondrial respiratory chain complex.

CONCLUSION

NK cells exhibit heightened sensitivity to the MXF environment. Different NK subsets upregulate the expression of cytokines and chemokines through different activation pathways. Concurrently, MXF induces impairment of the mitochondrial oxidative phosphorylation system, culminating in apoptosis.

The Interplay between Antibiotics and the Host Immune Response in Sepsis: From Basic Mechanisms to Clinical Considerations: A Comprehensive Narrative Review

Sepsis poses a significant global health challenge due to immune system dysregulation. This narrative review explores the complex relationship between antibiotics and the immune system, aiming to clarify the involved mechanisms and their clinical impacts. From pre-clinical studies, antibiotics exhibit various immunomodulatory effects, including the regulation of pro-inflammatory cytokine production, interaction with Toll-Like Receptors, modulation of the P38/Pmk-1 Pathway, inhibition of Matrix Metalloproteinases, blockade of nitric oxide synthase, and regulation of caspase-induced apoptosis. Additionally, antibiotic-induced alterations to the microbiome are associated with changes in systemic immunity, affecting cellular and humoral responses. The adjunctive use of antibiotics in sepsis patients, particularly macrolides, has attracted attention due to their immune-regulatory effects. However, there are limited data comparing different types of macrolides. More robust evidence comes from studies on community-acquired pneumonia, especially in severe cases with a hyper-inflammatory response. While studies on septic shock have shown mixed results regarding mortality rates and immune response modulation, conflicting findings are also observed with macrolides in acute respiratory distress syndrome. In conclusion, there is a pressing need to tailor antibiotic therapy based on the patient's immune profile to optimize outcomes in sepsis management.

Pleiotropic effects of antibiotics on T cell metabolism and T cell-mediated immunity

T cells orchestrate adaptive and innate immune responses against pathogens and transformed cells. However, T cells are also the main adaptive effector cells that mediate allergic and autoimmune reactions. Within the last few years, it has become abundantly clear that activation, differentiation, effector function, and environmental adaptation of T cells is closely linked to their energy metabolism. Beyond the provision of energy equivalents, metabolic pathways in T cells generate building blocks required for clonal expansion. Furthermore, metabolic intermediates directly serve as a source for epigenetic gene regulation by histone and DNA modification mechanisms. To date, several antibiotics were demonstrated to modulate the metabolism of T cells especially by altering mitochondrial function. Here, we set out to systematically review current evidence about how beta-lactam antibiotics, macrolides, fluoroquinolones, tetracyclines, oxazolidinones, nitroimidazoles, and amphenicols alter the metabolism and effector functions of CD4+ T helper cell populations and CD8+ T cells in vitro and in vivo. Based on this evidence, we have developed an overview on how the use of these antibiotics may be beneficial or detrimental in T cell-mediated physiological and pathogenic immune responses, such as allergic and autoimmune diseases, by altering the metabolism of different T cell populations.

Delivering macrolide antibiotics to heal a broken heart - And other inflammatory conditions

Drug carriers to deliver macrolide antibiotics, such as azithromycin, show promise as antibacterial agents. Macrolide drug carriers have largely focused on improving the drug stability and pharmacokinetics, while reducing adverse reactions and improving antibacterial activity. Recently, macrolides have shown promise in treating inflammatory conditions by promoting a reparative effect and limiting detrimental pro-inflammatory responses, which shifts the immunologic setpoint from suppression to balance. While macrolide drug carriers have only recently been investigated for their ability to modulate immune responses, the previous strategies that deliver macrolides for antibacterial therapy provide a roadmap for repurposing the macrolide drug carriers for therapeutic interventions targeting inflammatory conditions. This review describes the antibacterial and immunomodulatory activity of macrolides, while assessing the past in vivo evaluation of drug carriers used to deliver macrolides with the intention of presenting a case for increased effort to translate macrolide drug carriers into the clinic.

Immune Parameters in Chickens Treated with Antibiotics and Probiotics during Early Life

The aim of the study was to compare the effect of the administration of antibiotics or probiotics on chickens in their first week of life, on selected parameters of humoral and cellular immunity, and on the bursa of Fabricius and spleen indices. The experiment was carried out on 90 one-day-old male broilers. The control group received no additive in the drinking water; the group GP received a probiotic providing Enterococcus faecium and Bacillus amyloliquefaciens; and the group GA received 10% enrofloxacin in the drinking water on the first five days of life. Administration of the antibiotic enrofloxacin or a probiotic containing E. faecium and B. amyloliquefaciens strains to chickens in their first week of life exerts pronounced immunomodulatory effects on humoral and cellular defense mechanisms in these birds. The changes in the subpopulations of B and T cells immediately following early administration of enrofloxacin or the probiotic were not observed at the age of 35 days. Early administration of enrofloxacin can pose a risk of suppression of humoral immunity, as indicated by the significant decrease in the total IgY concentration in the plasma of the chickens.

Repurposing Immunomodulatory Drugs to Combat Tuberculosis

Tuberculosis (TB) is an infectious disease caused by an obligate intracellular pathogen, Mycobacterium tuberculosis (M.tb) and is responsible for the maximum number of deaths due to a single infectious agent. Current therapy for TB, Directly Observed Treatment Short-course (DOTS) comprises multiple antibiotics administered in combination for 6 months, which eliminates the bacteria and prevents the emergence of drug-resistance in patients if followed as prescribed. However, due to various limitations viz., severe toxicity, low efficacy and long duration; patients struggle to comply with the prescribed therapy, which leads to the development of drug resistance (DR). The emergence of resistance to various front-line anti-TB drugs urgently require the introduction of new TB drugs, to cure DR patients and to shorten the treatment course for both drug-susceptible and resistant populations of bacteria. However, the development of a novel drug regimen involving 2-3 new and effective drugs will require approximately 20-30 years and huge expenditure, as seen during the discovery of bedaquiline and delamanid. These limitations make the field of drug-repurposing indispensable and repurposing of pre-existing drugs licensed for other diseases has tremendous scope in anti-DR-TB therapy. These repurposed drugs target multiple pathways, thus reducing the risk of development of drug resistance. In this review, we have discussed some of the repurposed drugs that have shown very promising results against TB. The list includes sulfonamides, sulfanilamide, sulfadiazine, clofazimine, linezolid, amoxicillin/clavulanic acid, carbapenems, metformin, verapamil, fluoroquinolones, statins and NSAIDs and their mechanism of action with special emphasis on their immunomodulatory effects on the host to attain both host-directed and pathogen-targeted therapy. We have also focused on the studies involving the synergistic effect of these drugs with existing TB drugs in order to translate their potential as adjunct therapies against TB.

The effects of partially replacing animal protein sources with full fat black soldier fly larvae meal (Hermetia illucens) in nursery diets on growth performance, gut morphology, and immune response of pigs

One hundred and forty-four newly weaned pigs (6.74 ± 0.23 kg initial BW; 21 d of age) were used to determine the effect of partially replacing animal protein sources with black solider fly larvae meal (BSFLM) in nursery diets on growth performance, gut morphology, and immune response. After weaning, pigs were placed in 24 pens (six pigs per pen) and pens were randomly assigned to one of four dietary treatments (study d 0; n = 6), which were fed over three phases (phases I, II, and III were fed for 7, 14, and 21 d, respectively). Two nursery diets were formulated with 25% (LowFF) and 50% (HighFF) of the animal protein sources replaced by full fat BSFLM. Conventional nursery diets including animal protein sources without (CON−) and with antibiotics (220 mg Aureomycin per kg of complete feed; CON+) served as controls. On d 8, two pigs per pen were sacrificed to collect organ weights and for intestinal histomorphological measurements. On d 9 and d 23, two pigs per pen were vaccinated with the novel antigen ovalbumin (OVA). Blood samples were collected on d 9, d 23, and d 38 to assess concentrations of plasma haptoglobin and OVA-specific immunoglobulins G (IgG) and IgG1. On d 38, the same two pigs per pen underwent a dermal hypersensitivity test and skin-fold thickness was measured at 0, 6, 24, and 48 h postintradermal injection with OVA. Pigs fed the CON- had greater ADFI and lower G:F in phase II vs. those fed CON+ and HighFF diets (P < 0.05 and P < 0.05); intermediate ADFI was observed for pigs fed the LowFF diet. Overall in the nursery period, ADG (496 ± 13 g), ADFI (743 ± 23 g), G:F, and final BW (27.61 ± 0.66 kg) were not different among dietary treatments. There were no differences in organ weights, jejunal or ileal villus heights, or crypt depths among dietary treatments. There were no differences in OVA-specific IgG, IgG1, or plasma haptoglobin among dietary treatments at any of the blood sampling times. Although not different, pigs fed the LowFF, HighFF, and CON+ diets had respectively 2.0×, 1.7×, and 1.4× greater dermal hypersensitivity response to OVA versus those fed CON−. Both inclusion levels of BSFLM in nursery diets supported growth performance, gut morphology, and indices of immune function not different from the CON+, which suggest that full fat BSFLM can replace at least 50% of animal protein sources in nursery diets of pigs without any deleterious effects on pig growth.

Effects of crystalline penicillin G sodium on human T-cells differentiation

Background

Although antibiotics are well-known for their anti-bacterial effects, their inaugurated immunomodulatory roles in chronic inflammatory diseases have not elucidated yet. Anecdotal reports support the beneficial effects of parenteral penicillin in arthritis suggesting an immunomodulatory other than antibacterial effects for penicillin. The present study was designed to address the possible effects of penicillin G sodium (PCN-G) on different T-helper cells differentiation.

Materials and Methods

In this experimental study, peripheral blood mononuclear cells (PBMCs) of 10 healthy donors were isolated using Ficoll density gradient. The stimulated PBMCs by anti-CD3, anti-CD28, and anti-CD69 were cultured in the presence of 120 μg/ml of PCN-G. Foxp3, T-bet, RORγT, GATA3 as well as interferon-gamma (IFN-γ) and interleukin (IL)-17A mRNA in stimulated cells were measured by the real-time polymerase chain reaction. Mann-Whitney U-test was used for determining differences between the medium of gene expression levels of stimulated cell population and unstimulated cells by PCN. Correlations between the related genes were determined using the Spearman test.

Results

Based on the results, T-bet gene expression levels were similar in stimulated cells by PCN G after 24 and 48 h while significant reduction was observed after 72 incubation with PCN G (difference = 3; 0.09-0.34; P = 0.031). Meanwhile, treated cells with PCN G expressed decreased levels of IFN-γ (difference = 8.0; 0.49-1.07; P = 0.001) and IL-17A (difference = 2.2; 0.05-0.75; P ≤ 0.05) genes comparing to unstimulated cell by PCN-G. GATA3 genes expression levels downregulated by PCN G after 72 h of incubation by PBMCs (difference = 1.1; 0.77-0.88; P = 0.035).

Conclusion

Our results confirmed the immunomodulatory role of PCN G by affecting the expression of different cytokines genes in PBMCs.

Immunomodulatory Effects of Azithromycin Revisited: Potential Applications to COVID-19

The rapid advancement of the COVID-19 pandemic has prompted an accelerated pursuit to identify effective therapeutics. Stages of the disease course have been defined by viral burden, lung pathology, and progression through phases of the immune response. Immunological factors including inflammatory cell infiltration and cytokine storm have been associated with severe disease and death. Many immunomodulatory therapies for COVID-19 are currently being investigated, and preliminary results support the premise of targeting the immune response. However, because suppressing immune mechanisms could also impact the clearance of the virus in the early stages of infection, therapeutic success is likely to depend on timing with respect to the disease course. Azithromycin is an immunomodulatory drug that has been shown to have antiviral effects and potential benefit in patients with COVID-19. Multiple immunomodulatory effects have been defined for azithromycin which could provide efficacy during the late stages of the disease, including inhibition of pro-inflammatory cytokine production, inhibition of neutrophil influx, induction of regulatory functions of macrophages, and alterations in autophagy. Here we review the published evidence of these mechanisms along with the current clinical use of azithromycin as an immunomodulatory therapeutic. We then discuss the potential impact of azithromycin on the immune response to COVID-19, as well as caution against immunosuppressive and off-target effects including cardiotoxicity in these patients. While azithromycin has the potential to contribute efficacy, its impact on the COVID-19 immune response requires additional characterization so as to better define its role in individualized therapy.

A Review of Immunomodulatory Effects of Fluoroquinolones

Past researches indicate that some types of antibiotics, apart from their antimicrobial effects, have some other important effects which indirectly are exerted by modulating and regulating the immune system's mediators. Among the compounds with antimicrobial effects, fluoroquinolones (FQs) are known as synthetic antibiotics, which exhibit the property of decomposing of DNA and prevent bacterial growth by inactivating the enzymes involved in DNA twisting, including topoisomerase II (DNA gyrase) and IV. Interestingly, immune responses are indirectly modulated by FQs through suppressing pro-inflammatory cytokines, such as interleukin 1 (IL-1), IL-6, tumor necrosis factor-alpha (TNF-α), and super-inducing IL-2, which tend to increase both the growth and activity of T and B lymphocytes. In addition, they affect the development of immune responses by influencing of expression of other cytokines and mediators. This study aims to review past research on the immunomodulatory effects of FQs on the expression of cytokines, especially IL-2 and to discuss controversial investigations.

β-Glucan of Candida albicans Cell Wall Extract Inhibits Salmonella Typhimurium Colonization by Potentiating Cellular Immunity (CD8 + and CD4 + T Cells)

INTRODUCTION

Antimicrobial resistance has been reported in the drugs used for the treatment of typhoid fever. The immunomodulatory substance β-glucan can be used as an alternative therapy as it potentiates host immunity. The aims of this study are to observe the effect of Candida albicans cell wall (CCW) extract towards host immunity (TCD8+ and TCD4+ cells in spleen, intestinal sIgA) and its capacity to kill Salmonella in the intestine and liver of typhoid fever mice models.

METHODS

Typhoid fever mice models were created by infecting mice with S. Typhimurium orally. Mice were divided into four groups: the Non-Infected, Infected, CCW (infected mice treated with 300 µg CCW extract/mouse once a day), and Ciprofloxacin groups (infected mice treated with 15 mg/kg BW ciprofloxacin twice a day).

RESULTS

Secretory IgA (sIgA) concentrations of mice in the CCW group remained unchanged. However, their TCD4+ and TCD8+ cells increased substantially compared to those in the Non-Infected group. In the Ciprofloxacin group, sIgA concentrations increased markedly compared to those in the Non-Infected and CCW groups; TCD4+ and TCD8+ cells also increased significantly compared to those in the Infected Group, but not significant compared to those in the CCW group. Colonization of S. Typhimurium in the intestine and liver decreased significantly in the CCW and Ciprofloxacin groups compared to that in the Infected group, with the lowest reduction being found in the Ciprofloxacin group.

CONCLUSIONS

The inhibition of S. Typhimurium colonization by CCW is associated with the increase in TCD4+ and TCD8+ cells.

Oxaliplatin regulates myeloid-derived suppressor cell-mediated immunosuppression via downregulation of nuclear factor-κB signaling

Myeloid‐derived suppressor cells (MDSCs) represent one of the major types of immunoregulatory cells present under abnormal conditions, including cancer. These cells are characterized by their immature phenotype and suppressive effect on various immune effectors. In both human and mouse, there are two main subsets of MDSCs: polymorphonuclear (PMN)‐MDSCs and mononuclear (Mo)‐MDSCs. Thus, strategies to regulate MDSC‐mediated immunosuppression could result in the enhancement of anticancer immune responses. Oxaliplatin, a platinum‐based anticancer agent, is widely used in clinical settings. It is known to induce cell death by interfering with double‐stranded DNA and interrupting its replication and transcription. In this study, we found that oxaliplatin has the potential to regulate MDSC‐mediated immunosuppression in cancer. First, oxaliplatin selectively depleted MDSCs, especially Mo‐MDSCs, but only minimally affected T cells. In addition, sublethal doses of oxaliplatin eliminated the immunosuppressive capacity of MDSCs and induced the differentiation of MDSCs into mature cells. Oxaliplatin treatment diminished the expression of the immunosuppressive functional mediators arginase 1 (ARG1) and NADPH oxidase 2 (NOX2) in MDSCs, while an MDSC‐depleting agent, gemcitabine, did not downregulate these factors significantly. Oxaliplatin‐conditioned MDSCs had no tumor‐promoting activity in vivo. In addition, oxaliplatin modulated the intracellular NF‐κB signaling in MDSCs. Thus, oxaliplatin has the potential to be used as an immunoregulatory agent as well as a cytotoxic drug in cancer treatment.

In Vitro Study of the Modulatory Effects of Levofloxacin and BCG on Secretion of Proinflammatory Cytokines in Infiltrative Pulmonary Tuberculosis

The effects levofloxacin (fluoroquinolone) and vaccinal BCG strain on cytokine production by blood mononuclear leukocytes was studied in patients with infiltrative pulmonary tuberculosis. Combined treatment with levofloxacin and vaccinal BCG strain suppressed the production of TNFα in drug-resistant pulmonary tuberculosis and production of IL-12 and IFNγ in drug-sensitive tuberculosis.

Immunobiological efficacy and immunotoxicity of novel synthetically prepared fluoroquinolone ethyl 6-fluoro-8-nitro-4-oxo-1,4-dihydroquinoline-3-carboxylate

The present study examined the cytotoxicity, anti-cancer reactivity, and immunomodulatory properties of new synthetically prepared fluoroquinolone derivative 6-fluoro-8-nitro-4-oxo-1,4-dihydroquinoline-3-carboxylate (6FN) in vitro. The cytotoxicity/toxicity studies (concentrations in the range 1-100μM) are focused on the cervical cancer cells HeLa, murine melanoma cancer cells B16, non-cancer fibroblast NIH-3T3 cells and reconstructed human epidermis tissues EpiDerm™. The significant growth inhibition of cancer cells HeLa and B16 was detected. The cytotoxicity was mediated via apoptosis-associated with activation of caspase-9 and -3. After 72h of treatment, the two highest 6FN concentrations (100 and 50μM) induced toxic effect on epidermis tissue EpiDerm™, even the structural changes in tissue were observed with concentration of 100μM. The effective induction of RAW 264.7 macrophages cell-release of pro- and anti-inflammatory T_H1, T_H2 and T_H17 cytokines, with anti-cancer and/or anti-infection activities, respectively, has been revealed even following low-dose exposition.

Enrofloxacin in therapeutic doses alters cytokine production by porcine PBMCs induced by lipopolysaccharide

The effect of enrofloxacin on cytokine secretion by porcine peripheral blood mononuclear cells (PBMCs) was studied. Twenty 8-20-week-old pigs were randomly divided into two groups: control (C, n = 10) and experimental (E, n = 10) were used. Pigs from group E received enrofloxacin at therapeutic dose for 5 consecutive days. Blood samples were collected at 0 (before antibiotic administration), 2, 4 (during antibiotic therapy) 6, 9, 14 21, 35, 49, and 63 d of study (after treatment). PBMCs of pigs from both groups were incubated with or without lipopolysaccharide (LPS). Ex vivo production on interleukin (IL)-4, IL-6, IL-10, INF-γ, and TNF-α were analyzed using ELISA assay. Intramuscular administration of enrofloxacin to healthy pigs for 5 consecutive days induced a transitory reduction of the ex vivo response of PBMCs to LPS in terms of IL-6 and TNF-α secretion. The level of IL-6 returned to day 0 level shortly after end of treatment, while the TNF-α production remained reduced 10 d after the end of treatment. Our results indicate that enrofloxacin given in vivo in therapeutic doses has an immunomodulatory effect through its capacity to inhibit ex vivo secretion of IL-6 and TNF-α by porcine PBMC after LPS stimulation.

Fluoroquinolones or macrolides in combination with β-lactams in adult patients hospitalized with community acquired pneumonia: a systematic review and meta-analysis

OBJECTIVE

The best treatment option for hospitalized patients with community-acquired pneumonia (CAP) has not been defined. The effectiveness of β-lactam/fluoroquinolone (BLFQ) versus β-lactam/macrolide (BLM) combinations for the treatment of patients with CAP was evaluated.

METHODS

PubMed, Scopus and the Cochrane Library were searched for observational cohort studies, non-randomized and randomized controlled trials providing data for patients with CAP receiving BLM or BLFQ. Mortality was the primary outcome. A meta-analysis was performed. MINORS and GRADE were used for data quality assessment.

RESULTS

Seventeen studies (16 684 patients) were included. Randomized trials were not identified. A variety of β-lactams, fluoroquinolones and macrolides were used within and between the studies. Mortality was reported at different time points. The available body of evidence had very low quality. In the analysis of unadjusted data, mortality with BLFQ was higher than with BLM (risk ratio 1.33, 95% CI 1.15-1.54, I² 28%). BLFQ was associated with higher mortality regardless of the study design, mortality recording time, study period and study BLM group mortality. BLFQ was associated with higher mortality in American but not European studies. No difference was observed in patients with bacteraemia and septic shock. In the meta-analysis of adjusted mortality data, a non-significant difference between the two regimens was observed (eight studies, adjusted risk ratio 1.26, 95% CI 0.95-1.67, I² 43%).

CONCLUSION

In the absence of data from randomized controlled trials recommendations cannot be made for or against either of the studied regimens in this group of hospitalized patients with CAP. Well designed randomized controlled trials comparing the two regimens are warranted.

Repurposing Drugs in Oncology (ReDO)-clarithromycin as an anti-cancer agent

Clarithromycin (CAM) is a well-known macrolide antibiotic available as a generic drug. CAM is traditionally used for many types of bacterial infections, treatment of Lyme disease and eradication of gastric infection with Helicobacter pylori. Extensive preclinical and clinical data demonstrate a potential role for CAM to treat various tumours in combination with conventional treatment. The mechanisms of action underlying the anti-tumour activity of CAM are multiple and include prolonged reduction of pro-inflammatory cytokines, autophagy inhibition, and anti-angiogenesis. Here, we present an overview of the current preclinical (in vitro and in vivo) and clinical evidence supporting the role of CAM in cancer. Overall these findings justify further research with CAM in many tumour types, with multiple myeloma, lymphoma, chronic myeloid leukaemia (CML), and lung cancer having the highest level of evidence. Finally, a series of proposals are being made to further investigate the use of CAM in clinical trials which offer the greatest prospect of clinical benefit to patients.

Cytokine correlations in youth with tic disorders

BACKGROUND

Studies have noted immunological disruptions in patients with tic disorders, including increased serum cytokine levels. This study aimed to determine whether or not cytokine levels could be correlated with tic symptom severity in patients with a diagnosed tic disorder.

METHODS

Twenty-one patients, ages 4-17 years (average 10.63±2.34 years, 13 males), with a clinical diagnosis of Tourette's syndrome (TS) or chronic tic disorder (CTD), were selected based on having clinic visits that coincided with a tic symptom exacerbation and a remission. Ratings of tic severity were assessed using the Yale Global Tic Severity Scale (YGTSS) and serum cytokine levels (interleukin [IL]-2, IL-4, IL-5, IL-10, IL-12p70, IL-13, interferon [IFN]-γ, tumor necrosis factor [TNF]-α, and granulocyte macrophage-colony stimulating factor [GM-CSF]) were measured using Luminex xMAP technology.

RESULTS

During tic symptom exacerbation, patients had higher median serum TNF-α levels (z=-1.962, p=0.05), particularly those on antipsychotics (U=9.00, p=0.033). Increased IL-13 was also associated with antipsychotic use during exacerbation (U=4.00, p=0.043) despite being negatively correlated to tic severity scores (ρ=-0.599, p=018), whereas increased IL-5 was associated with antibiotic use (U=6.5, p=0.035). During tic symptom remission, increased serum IL-4 levels were associated with antipsychotic (U=6.00, p=0.047) and antibiotic (U=1.00, p=0.016) use, whereas increased IL-12p70 (U=4.00, p=0.037) was associated with antibiotic use.

CONCLUSIONS

These findings suggest a role for cytokine dysregulation in the pathogenesis of tic disorders. It also points toward the mechanistic involvement and potential diagnostic utility of cytokine monitoring, particularly TNF-α levels. Larger, systematic studies are necessary to further delineate the role of cytokines and medication influences on immunological profiling in tic disorders.

Azithromycin suppresses CD4(+) T-cell activation by direct modulation of mTOR activity

Advanced macrolides, such as azithromycin (AZM) or clarithromycin (CLM), are antibiotics with immunomodulatory properties. Here we have sought to evaluate their in vitro influence on the activation of CD4(+) T-cells. Isolated CD4(+) T-cells were stimulated with agonistic anti-CD3/anti-CD28 monoclonal antibodies in the presence of 0.6 mg/L, 2.5 mg/L, 10 mg/L or 40 mg/L AZM or CLM. Cell proliferation, cytokine level in supernatants and cell viability was assessed. Intracellular signaling pathways were evaluated using reporter cell lines, FACS analysis, immunoblotting and in vitro kinase assays. AZM inhibited cell proliferation rate and cytokine secretion of CD4(+) T-cells in a dose-dependent manner. Similarly, high concentrations of CLM (40 mg/L) also suppressed these T-cell functions. Analysis of molecular signaling pathways revealed that exposure to AZM reduced the phosphorylation of the S6 ribosomal protein, a downstream target of mTOR. This effect was also observed at 40 mg/L CLM. In vitro kinase studies using recombinant mTOR showed that AZM inhibited mTOR activity. In contrast to rapamycin, this inhibition was independent of FKBP12. We show for the first time that AZM and to a lesser extent CLM act as immunosuppressive agents on CD4(+) T-cells by inhibiting mTOR activity. Our results might have implications for the clinical use of macrolides.

The role of atypical infections and macrolide therapy in patients with asthma

For many years, the clinical benefit of macrolide use has been recognized in specific groups of patients with pulmonary disease. Dramatic improvement in survival of patients with diffuse panbronchiolitis is the most striking example of successful macrolide use as well as treatment of community acquired pneumonia caused by the atypical bacteria Mycoplasma, Chlamydophila, and Legionella. There also has been documentation of reduction in the exacerbation rate and of improvement in quality of life in patients with cystic fibrosis, bronchiectasis, chronic obstructive pulmonary disease, and reduction in post-lung transplantation bronchiolitis frequency. There has long been an interest in treating patients with severe asthma by using macrolides, but research results have not shown consistent clinical benefit in their use in the "general" population of patients with severe asthma. Rather, the successful use of macrolides seems to be in those patients with either documented Mycoplasma or Chlamydophila infection, or noneosinophilic asthma. Patients with neutrophil predominant phenotype severe asthma tend to show a decline in exacerbation rate, improved peak expiratory flows, and improved quality of life when treated with macrolides. This article will review the use of macrolides in the treatment of asthma.

Immunomodulatory adjuvant therapy in severe community-acquired pneumonia

Severe pneumonia has a high mortality (38.2%) despite evidence-based therapy. Rising rates of antimicrobial resistance increase the urgency to develop new treatment strategies. Multiple adjuvant therapies for pneumonia have been investigated but none are currently licensed. Profound immune dysregulation occurs in patients with severe infection. An initial hyper-inflammatory response is followed by a secondary hypo-inflammatory response with 'immune-paralysis'. There is focus on the development of immunostimulatory agents to improve host ability to combat primary infection and reduce secondary infections. Successful treatments must be targeted to immune response; promising biomarkers exist but have not yet reached common bedside practice. We explore evidence for adjuvant therapies in community-acquired pneumonia. We highlight novel potential treatment strategies using a broad-based search strategy to include publications in pneumonia and severe sepsis. We explore reasons for the failure to develop effective adjuvant therapies and highlight the need for targeted therapy specific to immune activity.

Effect of moxifloxacin on survival, lipid peroxidation and inflammation in immunosuppressed rats with soft tissue infection caused by Stenotrophomonas maltophilia

In order to investigate the effect of moxifloxacin on survival, lipid peroxidation and inflammation in immunosuppressed rats with soft tissue infection caused by Stenotrophomonas maltophilia, 144 white male Wistar rats were randomized into six groups: Groups A and B received saline or moxifloxacin once per day, respectively; Groups C and D received saline or moxifloxacin twice per day, respectively, and Groups E and F received saline or moxifloxacin three times per day, respectively. Blood samples were taken at 6 and 30 hr after administration of S. maltophilia. Malonodialdehyde (MDA), WBC counts, bacterial tissue overgrowth, serum concentrations of moxifloxacin and survival were assessed. Survival analysis proved that treatment with moxifloxacin every 8 hr was accompanied by longer survival than occurred in any other group. Tissue cultures 30 hr after bacterial challenge showed considerably less bacterial overgrowth in the spleens and lungs of moxifloxacin-treated than in salinetreated animals, but not in their livers. At 6 hr there were no statistically significant differences between groups. However, at 30 hr, MDA concentrations were significantly greater (P = 0.044) and WBC counts significantly lower (P = 0.026) in group D than in group C. No statistically significant variations were observed between the other groups. Moxifloxacin possibly stimulates lipid peroxidation and enhances phagocytosis, as indicated by MDA production and survival prolongation, without being toxic, as indicated by WBC count. Therefore, under the appropriate conditions, moxifloxacin has a place in treatment of infections in immunosuppressed patients and of infections caused by S. maltophilia.

Comparison of gene expression profiles of the jejunum of broilers supplemented with a yeast cell wall-derived mannan oligosaccharide versus bacitractin methylene disalicylate

1. The addition of yeast cell wall (YCW) mannan fractions or low concentrations of antibiotics to the diet of broilers positively affects gut health by improving intestinal cell morphology and improves feed efficiency and performance; however the exact mechanisms are unclear. Based on these production responses, the objective of this study was to compare the effects of supplementing YCW and bacitracin methylene disalicylate (BMD) in the diet on mRNA levels in the jejunum of 6-week-old broilers. 2. Dietary treatments were a maize-soya control diet and the control diet with the addition of YCW or BMD. Birds (n = 7) from each dietary treatment were randomly selected and killed at d 42. Whole jejunum (with serosa) samples were collected for RNA isolation. Gene expression analysis was performed using the AffymetrixGeneChip Chicken Genome Array (Santa Clara, CA, USA). 3. Supplementation with YCW resulted in 928 genes that were significantly changed (456 down-regulated, 472 up-regulated) and supplementation with BMD resulted in 857 genes that significantly changed (408 down-regulated, 449 up-regulated). In addition, 316 genes were significantly changed by both YCW and BMD (146 down-regulated, 170 up-regulated). 4. BMD increased the expression of genes involved in lipid and carbohydrate metabolism and decreased expression of genes associated with T-helper cell pathways. Gene expression profiles from birds fed on diets containing YCW showed changes on a genomic level that correspond to slower gut cell turnover and therefore increased energy preservation for growth. 5. In conclusion, supplementation with BMD or YCW had similar influences on the number of differentially expressed genes in the jejunum. Biological functions common to both YCW and BMD with positive activation scores included antiviral response and antimicrobial response. Genes that were affected by BMD or YCW classified into both different and common biological functions and pathways related to improved metabolism and health in the jejunum.

Macrolide therapy in chronic inflammatory diseases

Macrolides are a group of antibiotics with a distinctive macrocyclic lactone ring combined with sugars (cladinose, desosamine). The action of macrolides is to block protein synthesis by binding to the subunit of 50S ribosome of bacteria. Prototype macrolide was erythromycin, which came into clinical practice in the 50s of the 20th century. Its antimicrobial spectrum covers the scope of the penicillins but is extended to the impact of atypical bacteria. In the 90s more drugs of this group were synthesized—they have less severe side effects than erythromycin, extended spectrum of Gram-negative bacteria. Macrolides are effective in treating mycobacterial infections especially in patients infected with HIV. It is now known that in addition to antibacterial abilities, macrolides have immunomodulatory effects—they inhibit the production of proinflammatory cytokines (TNF, IL1, 6, and 8) affect transcription factors (NF-κB) as well as costimulaton (CD 80) and adhesion molecules (ICAM). This review article focused not only on the their antimicrobial abilities but also on efficacy in the treatment of several inflammatory disorders independent of the infectious agent. Their wider use as immunomodulators requires further study, which can lead to an extension of indications for their administration.

Pathogen- and host-directed anti-inflammatory activities of macrolide antibiotics

Macrolide antibiotics possess several, beneficial, secondary properties which complement their primary antimicrobial activity. In addition to high levels of tissue penetration, which may counteract seemingly macrolide-resistant bacterial pathogens, these agents also possess anti-inflammatory properties, unrelated to their primary antimicrobial activity. Macrolides target cells of both the innate and adaptive immune systems, as well as structural cells, and are beneficial in controlling harmful inflammatory responses during acute and chronic bacterial infection. These secondary anti-inflammatory activities of macrolides appear to be particularly effective in attenuating neutrophil-mediated inflammation. This, in turn, may contribute to the usefulness of these agents in the treatment of acute and chronic inflammatory disorders of both microbial and nonmicrobial origin, predominantly of the airways. This paper is focused on the various mechanisms of macrolide-mediated anti-inflammatory activity which target both microbial pathogens and the cells of the innate and adaptive immune systems, with emphasis on their clinical relevance.

Effect of azithromycin on natural killer cell function

Azithromycin (AZM), a macrolide antibiotic for treating mycoplasma infections, may exhibit anti-inflammatory activity aside from its antimicrobial effect, providing additional therapeutic benefit. Natural killer (NK) cells, a first-line innate immune defense against microbial invasions, paradoxically exert a detrimental effect in protecting mycoplasma infection. Little was known regarding the effect of AZM on NK cells. In the present study, we investigated the ability of azithromycin to influence natural killer (NK) cell function with regard to activation, apoptosis and cytotoxic function. AZM had little effect on NK receptor expression and cytotoxic function of NK-92 cells. However, AZM did show a dose-dependent suppression on IL-15-induced CD69 expression of primary NK cells. AZM inhibited the cytotoxicity against K562 cells of resting and IL-15 activated primary NK cells possibly through down-regulation of perforin expression, especially on CD16(+)CD56(+) NK subsets. AZM exerted a dose-dependent inhibition of IFN-gamma and TNF-alpha production from NK-92 cells, but did not affect the cytokine production of IL-15 activated primary NK cells. Taken together, AZM down-regulates NK cytotoxicity and cytokine production and may provide therapeutic benefits aside from its antimicrobial activity.

Macrolides in the treatment of asthma

PURPOSE OF REVIEW

This review summarizes the importance of macrolide therapy in the treatment of asthma, discusses macrolide mechanisms of action, and outlines new clinical data supporting their use. The effects of macrolides on both the innate and adaptive immune responses are discussed.

RECENT FINDINGS

Subacute bacterial infection with both typical and atypical organisms contributes to poor asthma control. Identification of pathogens using polymerase chain reaction (PCR) and cultures from bronchoscopic samples directs antibiotic therapy and improves asthma control. PCR identification of Mycoplasma pneumoniae and Chlamydophila pneumoniae in asthmatics best identifies the macrolide responsive phenotype.

SUMMARY

Because of their effect on protein synthesis, macrolides have both antimicrobial and anti-inflammatory properties. Both mechanisms appear to be important in their clinical efficacy in treating a wide variety of pulmonary disorders, including asthma.

The influence of antibiotics on B-cell number, percentage, and distribution in the bursa of Fabricius of newly hatched chicks

Antibiotics are commonly used to prevent and treat poultry microbial infections, but certain antibiotic families depress humoral immunity, such as antibody production. Poultry humoral immunity depends on the normal functioning of the bursa of Fabricius and the B lymphocytes that mature in that gland. In this study, recommended therapeutic doses of enrofloxacin, florfenicol, or ceftiofur were administered to 2-d-old chicks. On d 7 post-hatch, bursae were sampled for histological, immunohistochemical, and flow cytometric determination of Bu-1-positive (Bu-1+) cell number, percentage, and distribution. The bursa of Fabricius from all treatment and control groups had normal morphology. The administration of antibiotics significantly decreased the number of Bu-1+ cells in the bursal medulla, with a simultaneous increase of these cells in the cortex. Flow cytometry revealed a significant decrease in the percentage of bursal Bu-1+ cells from all of the studied antibiotics: enrofloxacin (93.91 ± 3.27), florfenicol (87.84 ± 7.14), and ceftiofur (89.16 ± 5.68) compared with that of the control (96.48 ± 2.60). The combination of reduced percentages of Bu-1+ cells and a decrease in these cells in the medullary region suggests lower B cell maturation.

Feed supplemented with 3 different antibiotics improved food intake and decreased the activation of the humoral immune response in healthy weaned pigs but had differing effects on intestinal microbiota

The aim of this study was to determine the effects of 3 antibiotics used for pulmonary pathologies added in the feed of weaned pigs on growth performance, commensal microbiota, and immune response. At weaning, a total of 72 pigs were randomly assigned by BW and litter to 1 of the following diets: control (typical weaning diet), control + 400 mg of tilmicosin/kg, control + 600 mg of amoxicillin/kg, and control + 300 mg of doxycycline/kg. Individually penned pigs were slaughtered after 3 wk (12 pigs/treatment) or 4 wk (6 pigs/treatment). During the fourth week, all pigs received the control diet to test the residual effect of the antimicrobial supplementation. The antibiotic supplementation increased growth and feed intake during the first week (P < 0.01) and over the first 3 wk combined (P < 0.05). Gain-to-feed ratio tended to improve during the first week (P = 0.076) by the antibiotics compared with the control. Among the antibiotic treatments, no difference was observed in ADG and feed intake, which were also unchanged by the diet in the fourth week. The fecal enterobacteria counts were increased by amoxicillin on d 14 and 21 (P < 0.05 and 0.01, respectively) and were decreased by tilmicosin (P < 0.001) compared with the control. Amoxicillin decreased lactic acid bacteria (P < 0.01) counts compared with the control. The antibiotic supplementation tended to decrease total bacteria variability in the jejunum (Shannon index, P = 0.091) compared with the control. The antibiotic treatment decreased the mean total serum IgM concentration (P = 0.016) after 3 wk and did not change the mucosal histomorphometry of the small intestine. For tilmicosin, the observed positive action on piglet performance and feed intake can originate by the decreased costs of immune activation determined by the action on intestinal microbiota. For amoxicillin and doxycycline, the observation on intestinal and fecal microbiota seems to be not sufficient to explain their growth-promoting effect.

Azithromycin inhibits IL-5 production of T helper type 2 cells from asthmatic children

BACKGROUND

Childhood asthma is a type 2 helper T (Th2) cell-driven inflammatory airway disease characterized by recurrent episodes of airway obstruction. Azithromycin (AZM), a macrolide antibiotic exhibiting anti-inflammatory activity aside from its antibacterial effect, may prove beneficial for asthmatic children. This study aimed to determine the effect of AZM on Th2 cells from atopic asthmatic children and non-atopic controls.

METHODS

CD4+ cells were isolated from peripheral blood mononuclear cells of 9 patients with asthma and 9 non-atopic individuals. Cells were activated as Th0 and differentiated into Th2 cells. The effect of AZM on activated CD4+ cells was evaluated with respective cell proliferation and cytokine production.

RESULTS

Th0 and Th2 CD4+ T cells from atopic asthmatic children produced greater interleukin (IL)-5 (Th2 cytokine) but lower interferon (IFN)-γ (Th1 cytokine) compared to the non-atopic controls, respectively. AZM inhibited IL-5 production of Th0 and Th2 cells from atopic asthmatics in a dose-dependent fashion, without significantly affecting their IL-13 and IFN-γ production. A similar effect was observed in non-atopic controls except that AZM did inhibit IFN-γ production of their Th0 cells. AZM at a higher dose decreased cell viability by inhibiting CD4+ T cell proliferation and enhanced their apoptosis, an effect similarly observed in Th0 and Th2 cells, and did not differ between asthmatic children and controls.

CONCLUSION

Our finding that AZM preferentially downregulates IL-5 production suggests its therapeutic potentials in controlling childhood asthma.

Activities of rifampin, Rifapentine and clarithromycin alone and in combination against mycobacterium ulcerans disease in mice

Background

Treatment of Mycobacterium ulcerans disease, or Buruli ulcer (BU), has shifted from surgery to treatment with streptomycin(STR)+rifampin(RIF) since 2004 based on studies in a mouse model and clinical trials. We tested two entirely oral regimens for BU treatment, rifampin(RIF)+clarithromycin(CLR) and rifapentine(RPT)+clarithromycin(CLR) in the mouse model.

Methodology/Principal Findings

BALB/c mice were infected in the right hind footpad with M. ulcerans strain 1059 and treated daily (5 days/week) for 4 weeks, beginning 11 days after infection. Treatment groups included an untreated control, STR+RIF as a positive control, and test regimens of RIF, RPT, STR and CLR given alone and the RIF+CLR and RPT+CLR combinations. The relative efficacy of the drug treatments was compared on the basis of footpad CFU counts and median time to footpad swelling. Except for CLR, which was bacteriostatic, treatment with all other drugs reduced CFU counts by approximately 2 or 3 log₁₀. Median time to footpad swelling after infection was 5.5, 16, 17, 23.5 and 36.5 weeks in mice receiving no treatment, CLR alone, RIF+CLR, RIF alone, and STR alone, respectively. At the end of follow-up, 39 weeks after infection, only 48%, 26.4% and 16.3% of mice treated with RPT+CLR, RPT alone and STR+RIF had developed swollen footpads. An in vitro checkerboard assay showed the interaction of CLR and RIF to be indifferent. However, in mice, co-administration with CLR resulted in a roughly 25% decrease in the maximal serum concentration (Cmax) and area under the serum concentration-time curve (AUC) of each rifamycin. Delaying the administration of CLR by one hour restored Cmax and AUC values of RIF to levels obtained with RIF alone.

Conclusions/Significance

These results suggest that an entirely oral daily regimen of RPT+CLR may be at least as effective as the currently recommended combination of injected STR+oral RIF.

Buruli ulcer (BU) is found throughout the world but is particularly prevalent in West Africa. Until 2004, treatment for this disfiguring disease was surgical excision followed by skin grafting, procedures often requiring months of hospitalization. More recently, an 8-week regimen of oral rifampin and streptomycin administered by injection has become the standard of care recommended by the World Health Organization. However, daily injections require sterile needles and syringes to prevent spread of blood borne pathogens and streptomycin has potentially serious side effects, most notably hearing loss. We tested an entirely oral regimen, substituting the long acting rifapentine for rifampin and clarithromycin for streptomycin. We also evaluated each drug separately. We found that rifapentine alone is as good as rifampin plus streptomycin, but the simultaneous addition of effective clarithromycin doses, at least in the mouse, reduces the activity of both rifampin and rifapentine, making it difficult to assess the efficacy of the oral regimens in the model. Studies of serum drug concentrations indicated that separating treatment times by one hour or reducing the clarithromycin dose to one active in humans should overcome this issue in experimental and clinical BU treatment, respectively.

Effect of reserved line’s anti-tuberculosis medicines to antiinflammatory cytokine production for patients with pulmonary tuberculosis

The results of research show the impact of ofloxacin, para-aminosalicylic acid (PASA) and capreomycin in conjunction with the BCG vaccine strain to the cytokine-production ability of mononuclear peripheral blood leukocytes for patients with infiltrative pulmonary tuberculosis prior to specific antituberculosis therapy. The results show that ofloxacin has inducing effect on the secretion of interleukin (IL) 4 and transforming growth factor (TGF) β; PASA and capreomycin have such effect for the products of IL10 and TGFβ. This influence has a negative effect during the active development of the pathological process and during specific treatment.

Mechanisms of action and clinical application of macrolides as immunomodulatory medications

Macrolides have diverse biological activities and an ability to modulate inflammation and immunity in eukaryotes without affecting homeostatic immunity. These properties have led to their long-term use in treating neutrophil-dominated inflammation in diffuse panbronchiolitis, bronchiectasis, rhinosinusitis, and cystic fibrosis. These immunomodulatory activities appear to be polymodal, but evidence suggests that many of these effects are due to inhibition of extracellular signal-regulated kinase 1/2 (ERK1/2) phosphorylation and nuclear factor kappa B (NF-kappaB) activation. Macrolides accumulate within cells, suggesting that they may associate with receptors or carriers responsible for the regulation of cell cycle and immunity. A concern is that long-term use of macrolides increases the emergence of antimicrobial resistance. Nonantimicrobial macrolides are now in development as potential immunomodulatory therapies.

Mitochondrial reactive oxygen species control T cell activation by regulating IL-2 and IL-4 expression: mechanism of ciprofloxacin-mediated immunosuppression

This article shows that T cell activation-induced expression of the cytokines IL-2 and -4 is determined by an oxidative signal originating from mitochondrial respiratory complex I. We also report that ciprofloxacin, a fluoroquinolone antibiotic, exerts immunosuppressive effects on human T cells suppressing this novel mechanism. Sustained treatment of preactivated primary human T cells with ciprofloxacin results in a dose-dependent inhibition of TCR-induced generation of reactive oxygen species (ROS) and IL-2 and -4 expression. This is accompanied by the loss of mitochondrial DNA and a resulting decrease in activity of the complex I. Consequently, using a complex I inhibitor or small interfering RNA-mediated downregulation of the complex I chaperone NDUFAF1, we demonstrate that TCR-triggered ROS generation by complex I is indispensable for activation-induced IL-2 and -4 expression and secretion in resting and preactivated human T cells. This oxidative signal (H(2)O(2)) synergizes with Ca(2+) influx for IL-2/IL-4 expression and facilitates induction of the transcription factors NF-kappaB and AP-1. Moreover, using T cells isolated from patients with atopic dermatitis, we show that inhibition of complex I-mediated ROS generation blocks disease-associated spontaneous hyperexpression and TCR-induced expression of IL-4. Prolonged ciprofloxacin treatment of T cells from patients with atopic dermatitis also blocks activation-induced expression and secretion of IL-4. Thus, our work shows that the activation phenotype of T cells is controlled by a mitochondrial complex I-originated oxidative signal.

Immunomodulation in the critically ill

Immunotherapy in the critically ill is an appealing notion because of the apparent abnormal immune and inflammatory responses seen in so many patients. The administration of a medication that could alter immune responses and decrease mortality in patients with sepsis could represent a ‘magic bullet’. Various approaches have been tried over the last 20 yr: steroids; anti-endotoxin or anti-cytokine antibodies; cytokine receptor antagonists; and other agents with immune-modulating side-effects. However, in some respects, research along these lines has been unsuccessful or disappointing at best. The current state of knowledge is summarized with particular reference to sepsis and the acute respiratory distress syndrome.

The mitochondria targeted antioxidant MitoQ protects against fluoroquinolone-induced oxidative stress and mitochondrial membrane damage in human Achilles tendon cells

Tendinitis and tendon rupture during treatment with fluoroquinolone antibiotics is thought to be mediated via oxidative stress. This study investigated whether ciprofloxacin and moxifloxacin cause oxidative stress and mitochondrial damage in cultured normal human Achilles' tendon cells and whether an antioxidant targeted to mitochondria (MitoQ) would protect against such damage better than a non-mitochondria targeted antioxidant. Human tendon cells from normal Achilles' tendons were exposed to 0-0.3 mM antibiotic for 24 h and 7 days in the presence of 1 microM MitoQ or an untargeted form, idebenone. Both moxifloxacin and ciprofloxacin resulted in up to a 3-fold increase in the rate of oxidation of dichlorodihydrofluorescein, a marker of general oxidative stress in tenocytes (p<0.0001) and loss of mitochondrial membrane permeability (p<0.001). In cells treated with MitoQ the oxidative stress was less and mitochondrial membrane potential was maintained. Mitochondrial damage to tenocytes during fluoroquinolone treatment may be involved in tendinitis and tendon rupture.

Immunomodulatory actions of antibiotics

Introduction. Antimicrob drugs and immune system interaction has been studied since the pioneer works of Metchnikoff. After the introduction of antibiotics in clinical practice this area has attracted little attention of investigators, because of the lack of standards. This is the reason that the studying of the influence of antibiotics on immune system is still at its beginning. Aim: To point out the immunomodulatory action of some antibiotics on certain components of immune system. Methods and results. The literaure findings show that antibiotics exspress immunomodulatory action on some components of immune system such as fagocytes (polymorphonucleary, macrophages, monocytes), cytokines, immunoglobulines, and on cellular immunity. The principles of antibiotics action on phagocyte are the inhibition of chemotaxis and oxidants production. Macrolides applied for a short time enchance the phagocytic functions while their long use leads to immunosupression. Some cephalosporines and rifampicin in therapeutic doses inhibit the oxydative metabolism of macrophages. Tetracyclines, clindamycines, chloramphenicol and tobramycin inhibit the synthesis of superoxyd anione. The action of some antibiotics on cytokine and specific antibodies is also important. Cellular immunity can be affected as well. After administration of certain antibiotics it takes 1-2 weeks to reestablish normal cellular immunity, and for other even more. Conclusion. There is still no clear standing on real effects of antibiotics on the immune system. Clinicians should search for more information from this new-old field of investigation in order to give more adequate therapy to patients.

Macrolides beyond the conventional antimicrobials: a class of potent immunomodulators

The historical change in the natural course of diffuse panbronchiolitis (DPB), a fatal disorder of the airways, following the introduction of erythromycin in its treatment has focused attention of researchers on the anti-inflammatory properties of macrolides. Chronic inflammation of the airways accompanied by infiltration by neutrophils and overproduction of mucus and pro-inflammatory cytokines is observed in bronchial asthma, cystic fibrosis (CF), DPB, chronic obstructive pulmonary disease (COPD) and bronchiectasis. The airways of these patients are often colonised by mucoid Pseudomonas aeruginosa attached to epithelium by a biofilm. Bacteria intercommunicate for biofilm formation by a system of lactones known as quorum sensing. Macrolides inhibit mobility and quorum sensing of P. aeruginosa; they also decrease production of mucus by epithelial cells and biosynthesis of pro-inflammatory cytokines from monocytes and epithelial cells by inhibiting nuclear factor-kappaB. Large, randomised clinical trials for the management of these disorders with macrolides are not available, with the sole exception of four trials denoting benefit following long-term administration of azithromycin in patients with CF. That benefit is consistent with an increase in forced expiratory volume in 1s (FEV(1)) and a decrease in the rate of bacterial exacerbations. Studies with small numbers of patients with COPD revealed attenuation of the inflammatory reaction by macrolides. Experimental studies of Gram-negative sepsis have shown considerable attenuation of the systemic inflammatory response following intravenous administration of clarithromycin. Results of the effects of clarithromycin in patients with ventilator-associated pneumonia and sepsis in a large, randomised study of 200 patients are awaited.