Anti-inflammatory mechanism of action of azithromycin in LPS-stimulated J774A.1 cells

Severe COVID-19 infection: An institutional review and literature overview

BACKGROUND

Our study aimed to describe the group of severe COVID-19 patients at an institutional level, and determine factors associated with different outcomes.

METHODS

A retrospective chart review of patients admitted with severe acute hypoxic respiratory failure due to COVID-19 infection. Based on outcomes, we categorized 3 groups of severe COVID-19: (1) Favorable outcome: progressive care unit admission and discharge (2) Intermediate outcome: ICU care (3) Poor outcome: in-hospital mortality.

RESULTS

Eighty-nine patients met our inclusion criteria; 42.7% were female. The average age was 59.7 (standard deviation (SD):13.7). Most of the population were Caucasian (95.5%) and non-Hispanic (91.0%). Age, sex, race, and ethnicity were similar between outcome groups. Medicare and Medicaid patients accounted for 62.9%. The average BMI was 33.5 (SD:8.2). Moderate comorbidity was observed, with an average Charlson Comorbidity index (CCI) of 3.8 (SD:2.6). There were no differences in the average CCI between groups(p = 0.291). Many patients (67.4%) had hypertension, diabetes (42.7%) and chronic lung disease (32.6%). A statistical difference was found when chronic lung disease was evaluated; p = 0.002. The prevalence of chronic lung disease was 19.6%, 27.8%, and 40% in the favorable, intermediate, and poor outcome groups, respectively. Smoking history was associated with poor outcomes (p = 0.04). Only 7.9% were fully vaccinated. Almost half (46.1%) were intubated and mechanically ventilated. Patients spent an average of 12.1 days ventilated (SD:8.5), with an average of 6.0 days from admission to ventilation (SD:5.1). The intermediate group had a shorter average interval from admission to ventilator (77.2 hours, SD:67.6), than the poor group (212.8 hours, SD:126.8); (p = 0.001). The presence of bacterial pneumonia was greatest in the intermediate group (72.2%), compared to the favorable group (17.4%), and the poor group (56%); this was significant (p<0.0001). In-hospital mortality was seen in 28.1%.

CONCLUSION

Most patients were male, obese, had moderate-level comorbidity, a history of tobacco abuse, and government-funded insurance. Nearly 50% required mechanical ventilation, and about 28% died during hospitalization. Bacterial pneumonia was most prevalent in intubated groups. Patients who were intubated with a good outcome were intubated earlier during their hospital course, with an average difference of 135.6 hours. A history of cigarette smoking and chronic lung disease were associated with poor outcomes.

Periodontal disease prevalence and oral hygiene status of adults with cystic fibrosis: A case-control study

AIM

To investigate the prevalence of gingivitis and periodontitis, and the oral hygiene status of adults with cystic fibrosis (CF) in the Republic of Ireland.

MATERIALS AND METHODS

A case-control study in the form of a clinical examination of 92 adults with a diagnosis of CF was carried out in the adult CF unit in Cork University Hospital. A 40-item questionnaire was used to capture socio-demographic variables and medical and dental information. Two calibrated examiners carried out a periodontal assessment on participants, using the WHO-recommended CPI-modified index, and oral hygiene status was measured using the Greene-Vermillion index. The results were compared with a population-based control group of similar socio-demographic profile.

RESULTS

Oral hygiene levels (plaque and calculus) were significantly worse in people with CF, with a median plaque index of 0.83 (interquartile range [IQR] 0.333-1.542) in the CF group compared with 0.5 (IQR 0.167-0.667) in the non-CF group. Calculus index in the CF group was 0.33 (IQR 0.17-0.83) compared with 0.33 (IQR 0.125-0.33) in the non-CF group. However, periodontal disease levels were significantly lower in the CF group. Gingivitis (bleeding on probing ≥ 10% sites) was seen in 67.4% of the CF group, compared with 83.7% of the non-CF group, OR 0.365 (95% confidence interval [CI] 0.181-0.736), relative risk (RR) 0.779 (95% CI 0.655-0.928). Mild periodontitis (periodontal probing depth [PPD] < 5 mm) was seen in 15.2% of the CF group, compared with 31.5% of the non-CF group, OR 0.390 (CI 0.190-0.800), RR 0.483 (95% CI 0.273-0.852). Severe periodontitis (PPD ≥ 6 mm) was seen in 0% of the CF group, compared with 9.8% of the non-CF group. There was a tendency, albeit non-significant, towards reduced periodontitis in PWCF who regularly took antibiotics, particularly azithromycin.

CONCLUSIONS

In this study, adults with CF had poor oral hygiene practices, with high levels of plaque and calculus. Despite this finding, adults with CF had lower levels of clinical gingivitis and periodontitis than seen in a non-CF control group. Further study is required to examine the causes of this phenomenon.

Synergistic Effects of Azithromycin and STING Agonist Promote IFN-I Production by Enhancing the Activation of STING-TBK1 Signaling

Background

Azithromycin (AZM) is a macrolide antibiotic that exhibits anti-inflammatory and anti-viral infection properties by enhancing type-I interferon (IFN-I) responses. The stimulator of interferon genes (STING) can directly induce IFN-I production. However, elevated IFN-I induces auto-immune phenotypes such as systemic lupus erythematosus (SLE). The effects of AZM and STING on the production of IFN-I are unclear.

Objective

Therefore, this study aims to evaluate the role of AZM and STING on IFN-I responses in macrophages.

Methods

RAW 264.7 macrophages were treated with AZM with and without a STING-agonist (DMXAA), and the maturation of macrophages was determined using flow cytometry. Gene expression and pro-inflammatory cytokines were analyzed using qPCR and ELISA, respectively. Moreover, protein expression was investigated using Western blot assays and immunofluorescence.

Results

Our results show that AZM significantly induced M1 phenotypes, promoting surface molecule expansion of CD80 and MHC-II and production of IL-6 and TNF-α cytokines on DMXAA-stimulated macrophages. Furthermore, we found that AZM-increased mRNA levels of interferon-stimulated genes (ISGs) could be due to the high expression of STNG-TBK1 signaling in the presence of DMXAA.

Conclusion

Our data suggest that AZM enhancement of IFN-I responses was STING dependent in DMXAA-stimulated macrophages. These data underline a novel approach to AZM action-mediated STING-TBK1 signaling for regulating IFN-I responses and may further augment the scientific basis and potential use of AZM in clinical applications.

The tale of antibiotics beyond antimicrobials: Expanding horizons

Antibiotics had proved to be a godsend for mankind since their discovery. They were once the magical solution to the vexing problem of infection-related deaths. German scientist Paul Ehrlich had termed salvarsan as the silver bullet to treatsyphilis.As time passed, the magic of newly discovered silver bullets got tarnished with raging antibiotic resistance among bacteria and associated side-effects. Still, antibiotics remain the primary line of treatment for bacterial infections. Our understanding of their chemical and biological activities has increased immensely with advancement in the research field. Non-antibacterial effects of antibiotics are studied extensively to optimise their safer, broad-range use. These non-antibacterial effects could be both useful and harmful to us. Various researchers across the globe including our lab are studying the direct/indirect effects and molecular mechanisms behind these non-antibacterial effects of antibiotics. So, it is interesting for us to sum up the available literature. In this review, we have briefed the possible reason behind the non-antibacterial effects of antibiotics, owing to the endosymbiotic origin of host mitochondria. We further discuss the physiological and immunomodulatory effects of antibiotics. We then extend the review to discuss molecular mechanisms behind the plausible use of antibiotics as anticancer agents.

A Novel Approach for the Treatment of Aerobic Vaginitis: Azithromycin Liposomes-in-Chitosan Hydrogel

Biocompatible mucoadhesive formulations that enable a sustained drug delivery at the site of action, while exhibiting inherent antimicrobial activity, are of great importance for improved local therapy of vaginal infections. The aim of this research was to prepare and evaluate the potential of the several types of azithromycin (AZM)-liposomes (180-250 nm) incorporated into chitosan hydrogel (AZM-liposomal hydrogels) for the treatment of aerobic vaginitis. AZM-liposomal hydrogels were characterized for in vitro release, and rheological, texture, and mucoadhesive properties under conditions simulating the vaginal site of application. The role of chitosan as a hydrogel-forming polymer with intrinsic antimicrobial properties was explored against several bacterial strains typical for aerobic vaginitis as well as its potential effect on the anti-staphylococcal activity of AZM-liposomes. Chitosan hydrogel prolonged the release of the liposomal drug and exhibited inherent antimicrobial activity. Additionally, it boosted the antibacterial effect of all tested AZM-liposomes. All AZM-liposomal hydrogels were biocompatible with the HeLa cells and demonstrated mechanical properties suitable for vaginal application, thus confirming their potential for enhanced local therapy of aerobic vaginitis.

Prospects for macrolide therapy of asthma and COPD

Macrolide compounds, many of which are derived from natural sources, all share a lactone ring structure, but of varying sizes. Their biological activities differ with structure and size but tend to overlap. Marketed macrolide drugs include immunosuppressives and antibiotics. Some of the latter have been shown to exert anti-inflammatory activities, due to direct effects on inflammatory cells and processes when used for respiratory infections. Consequently, azithromycin is included in clinical guidelines for COPD and asthma treatment, though it has the disadvantage, as an antibiotic, of increasing bacterial resistance. COPD and asthma, however, like several chronic inflammatory diseases involving other organs, are driven to a large extent by epithelial barrier dysfunction. Recently, azithromycin was shown to directly enhance epithelial barrier function and a new class of derivatives, barriolides, is under development with the lead indication COPD. It is thus likely that by circumventing antibiosis and acting on a crucial etiological disease process, this type of agent will open up a new, safer approach to COPD and asthma therapy with macrolides.

Anti-Inflammatories in the Treatment of Dry Eye Disease: A Review

Inflammation is an important driver of dry eye disease (DED) pathogenesis. An initial insult that results in the loss of tear film homeostasis can initiate a nonspecific innate immune response that leads to a chronic and self-sustaining inflammation of the ocular surface, which results in classic symptoms of dry eye. This initial response is followed by a more prolonged adaptive immune response, which can perpetuate and aggravate inflammation and result in a vicious cycle of chronic inflammatory DED. Effective anti-inflammatory therapies can help patients exit this cycle, and effective diagnosis of inflammatory DED and selection of the most appropriate treatment are therefore key to successful DED management and treatment. This review explores the cellular and molecular mechanisms of the immune and inflammatory components of DED, and examines the evidence base for the use of currently available topical treatment options. These agents include topical steroid therapy, calcineurin inhibitors, T cell integrin antagonists, antibiotics, autologous serum/plasma therapy, and omega-3 fatty acid dietary supplements.

Clinical Trials Targeting Secondary Damage after Traumatic Spinal Cord Injury

Spinal cord injury (SCI) often causes loss of sensory and motor function resulting in a significant reduction in quality of life for patients. Currently, no therapies are available that can repair spinal cord tissue. After the primary SCI, an acute inflammatory response induces further tissue damage in a process known as secondary injury. Targeting secondary injury to prevent additional tissue damage during the acute and subacute phases of SCI represents a promising strategy to improve patient outcomes. Here, we review clinical trials of neuroprotective therapeutics expected to mitigate secondary injury, focusing primarily on those in the last decade. The strategies discussed are broadly categorized as acute-phase procedural/surgical interventions, systemically delivered pharmacological agents, and cell-based therapies. In addition, we summarize the potential for combinatorial therapies and considerations.

Immunomodulatory role of azithromycin: Potential applications to radiation-induced lung injury

Radiation-induced lung injury (RILI) including radiation-induced pneumonitis and radiation-induced pulmonary fibrosis is a side effect of radiotherapy for thoracic tumors. Azithromycin is a macrolide with immunomodulatory properties and anti-inflammatory effects. The immunopathology of RILI that results from irradiation is robust pro-inflammatory responses with high levels of chemokine and cytokine expression. In some patients, pulmonary interstitial fibrosis results usually due to an overactive immune response. Growing clinical studies recently proposed that the anti-inflammatory and immunomodulatory effects of azithromycin may benefit patients with acute lung injury. It has been shown potential benefits for patients with RILI in preclinical studies. Azithromycin has a variety of immunomodulatory effect to improve the process of disease, including inhibition of pro-inflammatory cytokines production participating in the regulatory function of macrophages, changes in autophagy, and inhibition of neutrophil influx. We review the published evidence of mechanisms of azithromycin, and focus on the potential effect of azithromycin on the immune response to RILI.

Pulmonary Function Tests as a Biomarker in Diffuse Idiopathic Pulmonary Neuroendocrine Cell Hyperplasia Patients Treated With Somatostatin Analogues

Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) describes an indolent, under-recognised and poorly understood pulmonary condition with fewer than 200 reported cases across the literature. Currently, cases are diagnosed following a biopsy of the primary lesion, with treatment options centring on symptomatic benefit as opposed to targeting the underlying aetiology. Classically, DIPNECH lesions have been described as slow growing and benign, but with growing awareness of the condition, reports of metastatic disease with significant symptomatic burden have been reported. However, effectively addressing the subset of DIPNECH patients with greater metastatic potential remains an unmet clinical need. Due to the similarities between DIPNECH and carcinoid patients, several centres have considered using somatostatin analogues to not only help symptomatically but also to initiate tumour regression. However, to date, there are limited biomarkers to help evaluate the benefit of such options. In this review, we consider the use of pulmonary function tests (PFTs) to help quantify the benefit of somatostatin analogues. Although much of the evidence stems from small single-centre studies, the use of PFTs within the treatment pathway for both localised and metastatic DIPNECH represents a meaningful improvement from subjective monitoring of disease.

Local Delivery of Azithromycin Nanoformulation Attenuated Acute Lung Injury in Mice

Humanity has suffered from the coronavirus disease 2019 (COVID-19) pandemic over the past two years, which has left behind millions of deaths. Azithromycin (AZ), an antibiotic used for the treatment of several bacterial infections, has shown antiviral activity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) as well as against the dengue, Zika, Ebola, and influenza viruses. Additionally, AZ has shown beneficial effects in non-infective diseases such as cystic fibrosis and bronchiectasis. However, the systemic use of AZ in several diseases showed low efficacy and potential cardiac toxicity. The application of nanotechnology to formulate a lung delivery system of AZ could prove to be one of the solutions to overcome these drawbacks. Therefore, we aimed to evaluate the attenuation of acute lung injury in mice via the local delivery of an AZ nanoformulation. The hot emulsification-ultrasonication method was used to prepare nanostructured lipid carrier of AZ (AZ-NLC) pulmonary delivery systems. The developed formulation was evaluated and characterized in vitro and in vivo. The efficacy of the prepared formulation was tested in the bleomycin (BLM) -mice model for acute lung injury. AZ-NLC was given by the intratracheal (IT) route for 6 days at a dose of about one-eighth oral dose of AZ suspension. Samples of lung tissues were taken at the end of the experiment for immunological and histological assessments. AZ-NLC showed an average particle size of 453 nm, polydispersity index of 0.228 ± 0.07, zeta potential of -30 ± 0.21 mV, and a sustained release pattern after the initial 50% drug release within the first 2 h. BLM successfully induced a marked increase in pro-inflammatory markers and also induced histological changes in pulmonary tissues. All these alterations were significantly reversed by the concomitant administration of AZ-NLC (IT). Pulmonary delivery of AZ-NLC offered delivery of the drug locally to lung tissues. Its attenuation of lung tissue inflammation and histological injury induced by bleomycin was likely through the downregulation of the p53 gene and the modulation of Bcl-2 expression. This novel strategy could eventually improve the effectiveness and diminish the adverse drug reactions of AZ. Lung delivery could be a promising treatment for acute lung injury regardless of its cause. However, further work is needed to explore the stability of the formulation, its pharmacokinetics, and its safety.

A comprehensive review of Artificial Intelligence and Network based approaches to drug repurposing in Covid-19

Conventional drug discovery and development is tedious and time-taking process; because of which it has failed to keep the required pace to mitigate threats and cater demands of viral and re-occurring diseases, such as Covid-19. The main reasons of this delay in traditional drug development are: high attrition rates, extensive time requirements, and huge financial investment with significant risk. The effective solution to de novo drug discovery is drug repurposing. Previous studies have shown that the network-based approaches and analysis are versatile platform for repurposing as the network biology is used to model the interactions between variety of biological concepts. Herein, we provide a comprehensive background of machine learning and deep learning in drug repurposing while specifically focusing on the applications of network-based approach to drug repurposing in Covid-19, data sources, and tools used. Furthermore, use of network proximity, network diffusion, and AI on network-based drug repurposing for Covid-19 is well-explained. Finally, limitations of network-based approaches in general and specific to network are stated along with future recommendations for better network-based models.

A determination of pan-pathogen antimicrobials?

While antimicrobial drug development has historically mitigated infectious diseases that are known, COVID-19 revealed a dearth of 'in-advance' therapeutics suitable for infections by pathogens that have not yet emerged. Such drugs must exhibit a property that is antithetical to the classical paradigm of antimicrobial development: the ability to treat infections by any pathogen. Characterisation of such 'pan-pathogen' antimicrobials requires consolidation of drug repositioning studies, a new and growing field of drug discovery. In this review, a previously-established system for evaluating repositioning studies is used to highlight 4 therapeutics which exhibit pan-pathogen properties, namely azithromycin, ivermectin, niclosamide, and nitazoxanide. Recognition of the pan-pathogen nature of these antimicrobials is the cornerstone of a novel paradigm of antimicrobial development that is not only anticipatory of pandemics and bioterrorist attacks, but cognisant of conserved anti-infective mechanisms within the host-pathogen interactome which are only now beginning to emerge. Ultimately, the discovery of pan-pathogen antimicrobials is concomitantly the discovery of a new class of antivirals, and begets significant implications for pandemic preparedness research in a world after COVID-19.

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.

Effects of intranasal azithromycin on features of cigarette smoke-induced lung inflammation

Airflow limitation in chronic obstructive pulmonary disease (COPD) is the result of exaggerated airway fibrosis and obliteration of the small airways due to persistent inflammation, and an impaired anti-oxidant response. EMT has been implicated as an active signalling process in cigarette smoke (CS)-induced lung pathology, and macrolide Azithromycin (AZT) use has gained interest in treating COPD. Here, we tested effectiveness of intra-nasal AZT alone and in combination with dexamethasone (DEX) on CS-induced acute lung inflammation. Human alveolar epithelial cells (A549) were treated with CS extract (CSE) for 48 h, and male Balb/c mice were exposed to CS (3 cigarettes-3 times/day) for 4 days. The effects of AZT alone (0.25 and 1.25 μM, in vitro; 0.5 and 5 mg/kg, in vivo) or in combination with DEX (1 μM, in vitro; 1 mg/kg, in vivo) on CS-induced cellular cytotoxicity, oxidative stress, inflammation, and lung function were assessed. AZT alone and in combination with DEX significantly inhibited the CS (E)-induced expression of mesenchymal protein markers and the regulatory protein β-catenin. Furthermore, AZT by itself or in combination with DEX significantly suppressed CS-induced expression of the proinflammtory cytokines TNFα, IL1β and IL6 and prevented pNFkB. Mechanistically, AZT restored the CS-induced reduction in anti-oxidant transcription factor NRF2 and upregulated HDAC2 levels, thereby repressing inflammatory gene expression. Beneficial effects of AZT functionally translated in improved lung mechanics in vivo. Further preclinical and clinical studies are warranted to fully establish and validate the therapeutic efficacy of AZT as a mono- or combination therapy for the treatment of COPD.

Nonantimicrobial Actions of Macrolides: Overview and Perspectives for Future Development

Macrolides are among the most widely prescribed broad spectrum antibacterials, particularly for respiratory infections. It is now recognized that these drugs, in particular azithromycin, also exert time-dependent immunomodulatory actions that contribute to their therapeutic benefit in both infectious and other chronic inflammatory diseases. Their increased chronic use in airway inflammation and, more recently, of azithromycin in COVID-19, however, has led to a rise in bacterial resistance. An additional crucial aspect of chronic airway inflammation, such as chronic obstructive pulmonary disease, as well as other inflammatory disorders, is the loss of epithelial barrier protection against pathogens and pollutants. In recent years, azithromycin has been shown with time to enhance the barrier properties of airway epithelial cells, an action that makes an important contribution to its therapeutic efficacy. In this article, we review the background and evidence for various immunomodulatory and time-dependent actions of macrolides on inflammatory processes and on the epithelium and highlight novel nonantibacterial macrolides that are being studied for immunomodulatory and barrier-strengthening properties to circumvent the risk of bacterial resistance that occurs with macrolide antibacterials. We also briefly review the clinical effects of macrolides in respiratory and other inflammatory diseases associated with epithelial injury and propose that the beneficial epithelial effects of nonantibacterial azithromycin derivatives in chronic inflammation, even given prophylactically, are likely to gain increasing attention in the future. SIGNIFICANCE STATEMENT: Based on its immunomodulatory properties and ability to enhance the protective role of the lung epithelium against pathogens, azithromycin has proven superior to other macrolides in treating chronic respiratory inflammation. A nonantibiotic azithromycin derivative is likely to offer prophylactic benefits against inflammation and epithelial damage of differing causes while preserving the use of macrolides as antibiotics.

Azithromycin alleviates the severity of rheumatoid arthritis by targeting the UPR component GRP78

BACKGROUND AND PURPOSE

Azithromycin (AZM) is a macrolide antibiotic with well-described anti-inflammatory properties. This study aimed to substantiate the treatment potential of AZM in rheumatoid arthritis (RA).

EXPERIMENTAL APPROACH

Gene expression profiles were collected by RNA sequencing, and the effects of AZM were assessed in functional assays. In vitro and in vivo assays were performed to examine the effects of AZM-mediated blockade of glucose-regulated protein 78 (GRP78). Assays to define the anti-inflammatory activity of AZM using fibroblast-like synoviocytes (FLSs) from RA patients and collagen-induced arthritis (CIA) in DBA/1 mice were performed. Identification and characterization of the binding of AZM to GRP78 was performed using drug affinity responsive target stability assays, proteomics and cellular thermal shift assays. AZM-mediated inhibition of GRP78 and the dependence of the antiarthritic activity of AZM on GRP78 were assessed.

KEY RESULTS

AZM reduced proinflammatory factor production, cell migration, invasion and chemoattraction and enhanced apoptosis, thereby reducing the deleterious inflammatory response of RA FLSs in vitro. AZM ameliorated the severity of CIA lesions as efficiently as the anti-tumour necrosis factor (anti-TNF) biological agent etanercept (ETC). Transcriptional analyses suggested that AZM treatment impairs signalling cascades associated with cholesterol and lipid biosynthetic processes. GRP78 was identified as a novel target of AZM. AZM-mediated activation of the unfolded protein response (UPR) via the inhibition of GRP78 activity is required not only for inducing the expression of C/EBP-homologous protein (ChOP) but also for the activating sterol-regulatory element binding protein (SREBP) and its targeted genes involved in cholesterol and lipid biosynthetic processes. Furthermore, deletion of GRP78 abolished the antiarthritic activity of AZM.

CONCLUSION AND IMPLICATIONS

These findings confirmed that AZM is a therapeutic drug for RA treatment.

The epidemiology, clinical characteristics, and macrolide susceptibility of Mycoplasma pneumoniae pneumonia in children in Southern Taiwan, 2019-2020

BACKGROUND

Since the global use of the pneumococcal conjugate vaccine, Mycoplasma pneumoniae (MP) has become the most common bacterial cause of lower respiratory tract infections among children. Monitoring the changing epidemiology and antimicrobial resistance rates of this organism is important for MP clinical management.

METHODS

This study characterizes key features of MP during the 2019-2020 epidemic in children in Taiwan. The cohort included all hospitalized children under 18 years of age with polymerase chain reaction (PCR)-confirmed community-acquired mycoplasma pneumonia (CAMP) in southern Taiwan. Macrolide resistance was identified by mutations in domain V of MP 23S rRNA. Severe disease referred to symptoms warranting oxygen therapy, septic shock, or intensive care unit admission.

RESULTS

Among 495 LRTI patients, 195 (39.4%) had CAMP, of which 106 (54.4%) had concurrent serological evidence of MP infection. The diagnostic sensitivity of IgM in the acute phase was 65.6%. CAMP case numbers were highest from July 2019 to January 2020. The most common clinical presentations of CAMP were fever (99.0%), cough (99.0%), and coryza (31.8%). Despite a high rate of macrolide resistance (88.1%), macrolide-resistant MP (MRMP) did not differ from macrolide-sensitive MP (MSMP) in clinical course or severity. Delayed administration of effective antimicrobial treatment was also associated with severe disease (p < 0.05).

CONCLUSION

Early diagnosis and determination of MRMP are needed for effective management of MP infection.

COVID-19 with underdiagnosed influenza B and parainfluenza-2 co-infections in Saudi Arabia: Two case reports

The emerging of the COVID-19 pandemic is currently challenging for the public health system globally. Beyond SARS-CoV-2 pathogenicity, co-infections with recycling respiratory pathogens, whether bacterial, viral, or fungal, might increase disease symptoms, morbidity, and mortality.

In this study, we reported two COVID-19 cases in the early phase of the virus spread in Saudi Arabia with underdiagnosed respiratory viruses’ co-infections, influenza B and Parainfluenza-2, detected retrospectively. Fortunately, both patients recovered and were discharged home.

Underestimation of co-infection among COVID19 patients might lead to hospital stay prolongation and increases morbidity and mortality. Therefore, it is crucial to consider and screen for co-infecting pathogens among COVID-19 patients and those with risk factors.

Pathogenesis and Management of COVID-19

COVID-19, occurring due to SARS-COV-2 infection, is the most recent pandemic disease that has led to three million deaths at the time of writing. A great deal of effort has been directed towards altering the virus trajectory and/or managing the interactions of the virus with its subsequent targets in the human body; these interactions can lead to a chain reaction-like state manifested by a cytokine storm and progress to multiple organ failure. During cytokine storms the ratio of pro-inflammatory to anti-inflammatory mediators is generally increased, which contributes to the instigation of hyper-inflammation and confers advantages to the virus. Because cytokine expression patterns fluctuate from one person to another and even within the same person from one time to another, we suggest a road map of COVID-19 management using an individual approach instead of focusing on the blockbuster process (one treatment for most people, if not all). Here, we highlight the biology of the virus, study the interaction between the virus and humans, and present potential pharmacological and non-pharmacological modulators that might contribute to the global war against SARS-COV-2. We suggest an algorithmic roadmap to manage COVID-19.

Multicomponent synthesis and anti-proliferative screening of biaryl triazole-containing cyclophanes

We report a practical two-step approach involving a Ugi 4-CR/ azide-alkyne cycloaddition for the synthesis of biaryl-containing cyclophanes. The series represents an extension of our previously reported macrocycles as an effort to enhance the anti-proliferative activity of this scaffold. In this variant, we incorporate a biphenyl moiety in the framework, thus enhancing the macrocycle size, lipophilicity, and structural diversity. Macrocycles were tested against different cell lines, being more cytotoxic against prostate (PC-3 and DU-145) and breast (MCF-7) tumor cells. Gratifyingly, the most active compound showed a significative enhancement of PC-3 growth inhibition with respect to our previous series, reaffirming the potential anti-proliferative activity of this kind of cyclophanes.

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.

The endosomal lipid bis(monoacylglycero) phosphate as a potential key player in the mechanism of action of chloroquine against SARS-COV-2 and other enveloped viruses hijacking the endocytic pathway

The anti-malarial drug Chloroquine (CQ) and its derivative hydroxychloroquine have shown antiviral activities in vitro against many viruses, including coronaviruses, dengue virus and the biosafety level 4 Nipah and Hendra paramyxoviruses. The in vivo efficacy of CQ in the treatment of COVID-19 is currently a matter of debate. CQ is a lysosomotrophic compound that accumulates in lysosomes, as well as in food vacuoles of Plasmodium falciparum. In the treatment of malaria, CQ impairs the digestion and growth of the parasite by increasing the pH of the food vacuole. Similarly, it is assumed that the antiviral effects of CQ results from the increase of lysosome pH and the inhibition of acidic proteases involved in the maturation of virus fusion protein. CQ has however other effects, among which phospholipidosis, characterized by the accumulation of multivesicular bodies within the cell. The increase in phospholipid species particularly concerns bis(monoacylglycero)phosphate (BMP), a specific lipid of late endosomes involved in vesicular trafficking and pH-dependent vesicle budding. It was shown previously that drugs like progesterone, the cationic amphiphile U18666A and the phospholipase inhibitor methyl arachidonyl fluoro phosphonate (MAFP) induce the accumulation of BMP in THP-1 cells and decrease cell infection by human immunodeficiency virus. HIV viral particles were found to be retained into large endosomal-type vesicles, preventing virus spreading. Since BMP was also reported to favour virus entry through hijacking of the endocytic pathway, we propose here that BMP could play a dual role in viral infection, with its antiviral effects triggered by lysosomotropic drugs like CQ.

Antibiotics with therapeutic effects on spinal cord injury: a review

Accumulating evidence indicates that a considerable number of antibiotics exert anti-inflammatory and neuroprotective effects in different central and peripheral nervous system diseases including spinal cord injury (SCI). Both clinical and preclinical studies on SCI have found therapeutic effects of antibiotics from different families on SCI. These include macrolides, minocycline, β-lactams, and dapsone, all of which have been found to improve SCI sequels and complications. These antibiotics may target similar signaling pathways such as reducing inflammatory microglial activity, promoting autophagy, inhibiting neuronal apoptosis, and modulating the SCI-related mitochondrial dysfunction. In this review paper, we will discuss the mechanisms underlying therapeutic effects of these antibiotics on SCI, which not only could supply vital information for investigators but also guide clinicians to consider administering these antibiotics as part of a multimodal therapeutic approach for management of SCI and its complications.

Immunomodulation by macrolides: therapeutic potential for critical care

Critical illness is associated with immune dysregulation, characterised by concurrent hyperinflammation and immune suppression. Hyperinflammation can result in collateral tissue damage and organ failure, whereas immune suppression has been implicated in susceptibility to secondary infections and reactivation of latent viruses. Macrolides are a class of bacteriostatic antibiotics that are used in the intensive care unit to control infections or to alleviate gastrointestinal dysmotility. Yet macrolides also have potent and wide-ranging immunomodulatory properties, which might have the potential to correct immune dysregulation in patients who are critically ill without affecting crucial antimicrobial defences. In this Review, we provide an overview of preclinical and clinical studies that point to the beneficial effects of macrolides in acute diseases relevant to critical care, and we discuss the possible underlying mechanisms of their immunomodulatory effects. Further studies are needed to explore the therapeutic potential of macrolides in critical illness, to identify subgroups of patients who might benefit from treatment, and to develop novel non-antibiotic macrolide derivatives with improved immunomodulatory properties.

A multi-centre open-label two-arm randomised superiority clinical trial of azithromycin versus usual care in ambulatory COVID-19: study protocol for the ATOMIC2 trial

Background

Azithromycin is an orally active synthetic macrolide antibiotic with a wide range of anti-bacterial, anti-inflammatory and antiviral properties. It is a safe, inexpensive, generic licenced drug available worldwide and manufactured to scale and is a potential candidate therapy for pandemic coronavirus disease 2019 (COVID-19). Azithromycin was widely used to treat severe SARS-CoV and MERS-CoV, but to date, no randomised data are available in any coronavirus infections.

Other ongoing trials are exploring short courses of azithromycin either in early disease, within the first 7 days of symptoms, when azithromycin’s antiviral properties may be important, or late in disease when anti-bacterial properties may reduce the risk of secondary bacterial infection. However, the molecule’s anti-inflammatory properties, including suppression of pulmonary macrophage-derived pro-inflammatory cytokines such as interleukins-1β, -6, -8, and -18 and cytokines G-CSF and GM-CSF may provide a distinct therapeutic benefit if given in as a prolonged course during the period of progression from moderate to severe disease.

Methods

ATOMIC2 is a phase II/III, multi-centre, prospective, open-label, two-arm randomised superiority clinical trial of azithromycin versus standard care for adults presenting to hospital with COVID-19 symptoms who are not admitted at initial presentation. We will enrol adults, ≥ 18 years of age assessed in acute hospitals in the UK with clinical diagnosis of COVID-19 infection where management on an ambulatory care pathway is deemed appropriate. Participants will be randomised in a 1:1 ratio to usual care or to azithromycin 500 mg orally daily for 14 days with telephone follow-up at days 14 and 28. The primary objective is to compare the proportion with either death or respiratory failure requiring invasive or non-invasive mechanical ventilation over 28 days from randomisation. Secondary objectives include mortality/respiratory failure in those with a PCR-confirmed diagnosis; all-cause mortality; progression to pneumonia; progression to severe pneumonia; peak severity of illness and mechanistic analysis of blood and nasal biomarkers.

Discussion

This trial will determine the clinical utility of azithromycin in patients with moderately severe, clinically diagnosed COVID-19 and could be rapidly applicable worldwide.

Trial registration

ClinicalTrials.gov NCT04381962. Registered on 11 May 2020. EudraCT identifier 2020-001740-26. Opened for accrual on 29 May 2020.

Azithromycin and SARS-CoV-2 infection: Where we are now and where we are going

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Azithromycin (AZM) is a promising drug candidate for the treatment of the COVID-19.

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Studies so far on the use of AZM in COVID-19 patients have various methodological limitations.

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The evidence on the efficacy of AZM as an adjunct to hydroxychloroquine for COVID-19 is not enough yet.

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Combination of AZM and HCQ should be decided with caution due serious cardiac adverse effects.

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Currently, 21 clinical trials are being carried out on the use of AZM in COVID-19.

Resolution of Symptoms and Resumption of Sex After Diagnosis of Nongonococcal Urethritis Among Men Who Have Sex With Men

BACKGROUND

Standard counseling at nongonococcal urethritis (NGU) diagnosis includes advice to abstain from sex for at least 7 days and until symptoms resolve.

METHODS

From December 2014 to July 2018, we enrolled men who have sex with men and received azithromycin (1 g) for NGU at the Public Health-Seattle and King County STD Clinic. Over 12 weeks of follow-up, participants reported daily urethral symptoms and sexual activity on web-based diaries. Nongonococcal urethritis was defined as urethral symptoms or visible urethral discharge plus 5 or greater polymorphonuclear leukocytes per high-power field. Time of symptom resolution was defined as the first of 5 consecutive asymptomatic days.

RESULTS

Of 100 participants with NGU and no Chlamydia trachomatis (CT)/Mycoplasma genitalium (MG) coinfection, 36 (36%), 22 (22%), and 42 (42%) had CT-NGU, MG-NGU, and non-CT/non-MG NGU, respectively. Among men with MG-NGU, 94% had a macrolide resistance mutation. For all etiologies, median time to symptom resolution after azithromycin was 7 days (95% confidence interval [CI], 5-9); 37% had symptoms lasting longer than 7 days. For men with CT-NGU, MG-NGU, and non-CT/non-MG NGU, median time to symptom resolution was 4 days (95% CI, 2-6; 16% >7 days), undefined days (95% CI, 7 to undefined; 60% >7 days), and 7 days (95% CI, 5-11; 46% >7 days), respectively. Median time to first sexual activity (any type) was 12 days (95% CI, 11-17); it was 16 days (95% CI, 12-18) to first urethral sexual exposure. Twenty-seven percent did not avoid urethral exposure for the recommended period.

CONCLUSIONS

Counseling at NGU diagnosis should educate patients that symptoms may persist more than 7 days, particularly for non-CT NGU, and emphasize the rationale for the 7-day abstinence period.

In-vitro evaluation of a ciprofloxacin and azithromycin sinus stent for Pseudomonas aeruginosa biofilms

BACKGROUND

Chronic rhinosinusitis (CRS) is a chronic inflammatory disease characterized by persistent inflammation and bacterial infection. Ciprofloxacin and azithromycin are commonly prescribed antibiotics for CRS, but the ability to provide targeted release in the sinuses could mitigate side effects and improve drug concentrations at the infected site. This study was aimed to evaluate the efficacy of the novel ciprofloxacin-azithromycin sinus stent (CASS) in vitro.

METHODS

The CASS was created by coating ciprofloxacin (hydrophilic, inner layer) and azithromycin (hydrophobic, outer layer) onto a biodegradable poly-l-lactic acid (PLLA) stent. In-vitro evaluation included: (1) assessment of drug-coating stability within the stent using scanning electron microscopy (SEM); (2) determination of ciprofloxacin and azithromycin release kinetics; and (3) assessment of anti-biofilm activities against Pseudomonas aeruginosa.

RESULTS

The ciprofloxacin nanoparticle suspension in the inner layer was confirmed by zeta potential. Both ciprofloxacin (60 µg) and azithromycin (3 mg) were uniformly coated on the surface of the PLLA stents. The CASS showed ciprofloxacin/azithromycin sustained release patterns, with 80.55 ± 11.61% of ciprofloxacin and 93.85 ± 6.9% of azithromycin released by 28 days. The CASS also significantly reduced P aeruginosa biofilm mass compared with bare stents and controls (relative optical density units at 590-nm optical density: CASS, 0.037 ± 0.006; bare stent, 0.911 ± 0.015; control, 1.000 ± 0.000; p < 0.001; n = 3).

CONCLUSION

The CASS maintains a uniform coating and sustained delivery of ciprofloxacin and azithromycin, providing anti-biofilm activities against P aeruginosa. Further studies evaluating the efficacy of CASS in a preclinical model are planned.

Delayed Azithromycin Treatment Improves Recovery After Mouse Spinal Cord Injury

After spinal cord injury (SCI), macrophages infiltrate into the lesion and can adopt a wide spectrum of activation states. However, the pro-inflammatory, pathological macrophage activation state predominates and contributes to progressive neurodegeneration. Azithromycin (AZM), an FDA approved macrolide antibiotic, has been demonstrated to have immunomodulatory properties in a variety of inflammatory conditions. Indeed, we previously observed that post-SCI AZM treatment reduces pro-inflammatory macrophage activation. Further, a combined pre- and post-injury treatment paradigm improved functional recovery from SCI. Therefore, for the current study, we hypothesize that post-injury AZM treatment will improve recovery from SCI. To test this hypothesis, we examined the therapeutic potential of delayed AZM treatment on locomotor, sensory, and anatomical recovery. We administered AZM beginning 30-min, 3-h, or 24-h following contusion SCI in female mice, and then daily for 7 days. AZM administration beginning 30-min and 3-h post-injury improved locomotor recovery with increased stepping function relative to vehicle controls. Further, delaying treatment for 30-min after SCI significantly reduced lesion pathology. Initiating AZM treatment 24-h post-injury was not therapeutically effective. Regardless of the timing of the initial treatment, AZM did not statistically reduce the development of neuropathic pain (mechanical allodynia) nor increase neuron survival. Collectively, these results add to a growing body of evidence supporting AZM's translational potential as a therapeutic agent for SCI and other neuroinflammatory conditions in which patients currently have very few options.

Lysosomotropic cationic amphiphilic drugs inhibit adipocyte differentiation in 3T3-L1K cells via accumulation in cells and phospholipid membranes, and inhibition of autophagy

Some cationic amphiphilic drugs (CADs) have been individually reported to interfere with the differentiation of immune system cells, such as macrophages and dendritic cells. To investigate the possible generic nature of this process, in this study we aimed to see whether these drugs are capable of interfering with the differentiation of adipocytes. Further, we investigated whether this feature might be connected to the lysosomotropic character of these drugs, and their disturbance of intracellular membrane trafficking rather than to the individual pharmacologic properties of each drug. Thus, for the selected set of compounds consisting of seven structurally and pharmacologically diverse CADs and three non-CAD controls we have measured the impact on differentiation of 3T3-L1K murine preadipocytes to adipocytes. We conclude that CADs indeed inhibit adipocyte differentiation, as shown morphologically, at the level of lipid droplet formation and on the expression of genetic markers of adipocytes. Furthermore, the intensity of this inhibitory effect was found to strongly positively correlate with the extent of drug accumulation in adipocytes, with their affinity for phospholipid membranes, as well as with their ability to induce phospholipidosis and inhibit autophagy.

Azithromycin drives alternative macrophage activation and improves recovery and tissue sparing in contusion spinal cord injury

Background

Macrophages persist indefinitely at sites of spinal cord injury (SCI) and contribute to both pathological and reparative processes. While the alternative, anti-inflammatory (M2) phenotype is believed to promote cell protection, regeneration, and plasticity, pro-inflammatory (M1) macrophages persist after SCI and contribute to protracted cell and tissue loss. Thus, identifying non-invasive, clinically viable, pharmacological therapies for altering macrophage phenotype is a challenging, yet promising, approach for treating SCI. Azithromycin (AZM), a commonly used macrolide antibiotic, drives anti-inflammatory macrophage activation in rodent models of inflammation and in humans with cystic fibrosis.

Methods

We hypothesized that AZM treatment can alter the macrophage response to SCI and reduce progressive tissue pathology. To test this hypothesis, mice (C57BL/6J, 3-month-old) received daily doses of AZM (160 mg/kg) or vehicle treatment via oral gavage for 3 days prior and up to 7 days after a moderate-severe thoracic contusion SCI (75-kdyn force injury). Fluorescent-activated cell sorting was used in combination with real-time PCR (rtPCR) to evaluate the disposition and activation status of microglia, monocytes, and neutrophils, as well as macrophage phenotype in response to AZM treatment. An open-field locomotor rating scale (Basso Mouse Scale) and gridwalk task were used to determine the effects of AZM treatment on SCI recovery. Bone marrow-derived macrophages (BMDMs) were used to determine the effect of AZM treatment on macrophage phenotype in vitro.

Results

In accordance with our hypothesis, SCI mice exhibited significantly increased anti-inflammatory and decreased pro-inflammatory macrophage activation in response to AZM treatment. In addition, AZM treatment led to improved tissue sparing and recovery of gross and coordinated locomotor function. Furthermore, AZM treatment altered macrophage phenotype in vitro and lowered the neurotoxic potential of pro-inflammatory, M1 macrophages.

Conclusions

Taken together, these data suggest that pharmacologically intervening with AZM can alter SCI macrophage polarization toward a beneficial phenotype that, in turn, may potentially limit secondary injury processes. Given that pro-inflammatory macrophage activation is a hallmark of many neurological pathologies and that AZM is non-invasive and clinically viable, these data highlight a novel approach for treating SCI and other maladaptive neuroinflammatory conditions.

Electronic supplementary material

The online version of this article (doi:10.1186/s12974-015-0440-3) contains supplementary material, which is available to authorized users.

Azithromycin recovers reductions in barrier function in human gingival epithelial cells stimulated with tumor necrosis factor-α

OBJECTIVE

The gingival epithelium plays an important role in protecting against the invasion of periodontal pathogens, and the permeability of gingival epithelial cells has been implicated in the initiation of periodontitis. Azithromycin (AZM) has been used in the treatment of chronic inflammatory airway diseases because it regulates cell-cell contact in airway epithelial cells. Therefore, AZM may also regulate barrier function in gingival epithelial cells. In the present study, we examined the effects of AZM on the permeability of human gingival epithelial cells (HGEC) under inflammatory conditions in vitro.

MATERIALS AND METHODS

HGEC were stimulated by tumor necrosis factor-α (TNF-α) in the presence of AZM or p38 MAP kinase and ERK inhibitors. Permeability was assessed based on transepithelial electrical resistance (TER). The expression of E-cadherin, phosphorylated p38 MAP kinase, and ERK was analyzed by Western blotting.

RESULTS

TNF-α decreased TER in HGEC, and AZM and the p38 MAP kinase and ERK inhibitors recovered this decrease. AZM inhibited the phosphorylation of ERK and p38 MAP kinase in TNF-α-stimulated HGEC. Furthermore, AZM recovered the decrease in E-cadherin expression in HGEC stimulated with TNF-α.

CONCLUSIONS

These results suggested that AZM regulated gingival epithelial permeability through p38 MAP kinase and ERK signaling, and may contribute to suppress the inflammation in gingival tissue.

Effect of azithromycin on the LPS-induced production and secretion of phospholipase A2 in lung cells

Azithromycin is a member of macrolides, utilized in the treatment of infections. Independently, these antibiotics also possess anti-inflammatory and immunomodulatory properties. Phospholipase A2 isotypes, which are implicated in the pathophysiology of inflammatory lung disorders, are produced by alveolar macrophages and other lung cells during inflammatory response and can promote lung injury by destructing lung surfactant. The aim of the study was to investigate whether in lung cells azithromycin can inhibit secretory and cytosolic phospholipases A2, (sPLA2) and (cPLA2), respectively, which are induced by an inflammatory trigger. In this respect, we studied the lipopolysaccharide (LPS)-mediated production or secretion of sPLA2 and cPLA2 from A549 cells, a cancer bronchial epithelial cell line, and alveolar macrophages, isolated from bronchoalveolar lavage fluid of ARDS and control patients without cardiopulmonary disease or sepsis. Pre-treatment of cells with azithromycin caused a dose-dependent decrease in the LPS-induced sPLA2-IIA levels in A549 cells. This inhibition was rather due to reduced PLA2G2A mRNA expression and secretion of sPLA2-IIA protein levels, as observed by western blotting and indirect immunofluorescence by confocal microscopy, respectively, than to the inhibition of the enzymic activity per se. On the contrary, azithromycin had no effect on the LPS-induced production or secretion of sPLA2-IIA from alveolar macrophages. The levels of LPS-induced c-PLA2 were not significantly affected by azithromycin in either cell type. We conclude that azithromycin exerts anti-inflammatory properties on lung epithelial cells through the inhibition of both the expression and secretion of LPS-induced sPLA2-IIA, while it does not affect alveolar macrophages.

The design of novel classes of macrolides for neutrophil-dominated inflammatory diseases

Neutrophil-dominated inflammatory diseases, like chronic obstructive pulmonary disease, cystic fibrosis, bronchiectasis, bronchiolitis obliteras syndrome and non-eosinophilic asthma, present a significant medical problem lacking adequate therapy. Macrolide antibiotics have been reported to be effective in the treatment of the aforementioned diseases, for reasons unrelated to their antibacterial action. This has resulted in research activities aimed at gaining a better understanding of the immunomodulatory actions of macrolides and the synthesis of various novel anti-inflammatory macrolides without antimicrobial activity. Despite the difficult chemistry and lack of an extensive knowledge for their mechanism of action, several interesting molecules from this class, including potential clinical candidates, are on the horizon.

N-[3-(aminomethyl)benzyl]acetamidine (1400 W) as a potential immunomodulatory agent

This study was designed to investigate the relationship between NO, IL-12, and TNF-α production by J774A.1 macrophages activated with LPS and IFN-γ in the presence of N-[3-(aminomethyl)benzyl]acetamidine (1400 W). 1400 W is a novel, highly selective inhibitor of inducible nitric oxide synthase (iNOS). We compared the obtained data with the effect of N^G-monomethyl-L-arginine (L-NMMA) (a nonselective NOS inhibitor) and L-N^G-(1-iminoethyl)lysine (L-NIL) (a relatively selective inhibitor of iNOS activity) on cells in this model. To investigate the involvement of an exogenous NO on IL-12 and TNF-α production we used NO donor—S-nitrosocaptopril (S-NO-Cap). The most potent inhibitor of NO generation was 1400 W. This compound also markedly increased IL-12 p40 secretion and decreased TNF-α release. L-NIL suppressed both NO and TNF-α production, but it did not change IL-12 p40 synthesis. The effect of L-NMMA on NO generation was weaker than other inhibitors. Moreover, it decreased TNF-α secretion slightly but not significantly. IL-12 p40 production by stimulated cells was inhibited by S-NO-Cap in a dose dependent manner, but no effect on TNF-α release was observed. The potency and selectivity of 1400 W as an inhibitor of iNOS and cytokine release modifier are encouraging for therapeutic use.

Azithromycin is able to control Toxoplasma gondii infection in human villous explants

Background

Although Toxoplasma gondii infection is normally asymptomatic, severe cases of toxoplasmosis may occur in immunosuppressed patients or congenitally infected newborns. When a fetal infection is established, the recommended treatment is a combination of pyrimethamine, sulfadiazine and folinic acid (PSA). The aim of the present study was to evaluate the efficacy of azithromycin to control T. gondii infection in human villous explants.

Methods

Cultures of third trimester human villous explants were infected with T. gondii and simultaneously treated with either PSA or azithromycin. Proliferation of T. gondii, as well as production of cytokines and hormones by chorionic villous explants, was analyzed.

Results

Treatment with either azithromycin or PSA was able to control T. gondii infection in villous explants. After azithromycin or PSA treatment, TNF-α, IL-17A or TGF-β1 levels secreted by infected villous explants did not present significant differences. However, PSA-treated villous explants had decreased levels of IL-10 and increased IL-12 levels, while treatment with azithromycin increased production of IL-6. Additionally, T. gondii-infected villous explants increased secretion of estradiol, progesterone and HCG + β, while treatments with azithromycin or PSA reduced secretion of these hormones concurrently with decrease of parasite load.

Conclusions

In conclusion, these results suggest that azithromycin may be defined as an effective alternative drug to control T. gondii infection at the fetal-maternal interface.

Tulathromycin exerts proresolving effects in bovine neutrophils by inhibiting phospholipases and altering leukotriene B4, prostaglandin E2, and lipoxin A4 production

The accumulation of neutrophils and proinflammatory mediators, such as leukotriene B4 (LTB4), is a classic marker of inflammatory disease. The clearance of apoptotic neutrophils, inhibition of proinflammatory signaling, and production of proresolving lipids (including lipoxins, such as lipoxin A4 [LXA4]) are imperative for resolving inflammation. Tulathromycin (TUL), a macrolide used to treat bovine respiratory disease, confers immunomodulatory benefits via mechanisms that remain unclear. We recently reported the anti-inflammatory properties of TUL in bovine phagocytes in vitro and in Mannheimia haemolytica-challenged calves. The findings demonstrated that this system offers a powerful model for investigating novel mechanisms of pharmacological immunomodulation. In the present study, we examined the effects of TUL in a nonbacterial model of pulmonary inflammation in vivo and characterized its effects on lipid signaling. In bronchoalveolar lavage (BAL) fluid samples from calves challenged with zymosan particles (50 mg), treatment with TUL (2.5 mg/kg of body weight) significantly reduced pulmonary levels of LTB4 and prostaglandin E2 (PGE2). In calcium ionophore (A23187)-stimulated bovine neutrophils, TUL inhibited phospholipase D (PLD), cytosolic phospholipase A2 (PLA2) activity, and the release of LTB4. In contrast, TUL promoted the secretion of LXA4 in resting and A23187-stimulated neutrophils, while levels of its precursor, 15(S)-hydroxyeicosatetraenoic acid [15(S)-HETE], were significantly lower. These findings indicate that TUL directly modulates lipid signaling by inhibiting the production of proinflammatory eicosanoids and promoting the production of proresolving lipoxins.

Azithromycin: mechanisms of action and their relevance for clinical applications

Azithromycin is a macrolide antibiotic which inhibits bacterial protein synthesis, quorum-sensing and reduces the formation of biofilm. Accumulating effectively in cells, particularly phagocytes, it is delivered in high concentrations to sites of infection, as reflected in rapid plasma clearance and extensive tissue distribution. Azithromycin is indicated for respiratory, urogenital, dermal and other bacterial infections, and exerts immunomodulatory effects in chronic inflammatory disorders, including diffuse panbronchiolitis, post-transplant bronchiolitis and rosacea. Modulation of host responses facilitates its long-term therapeutic benefit in cystic fibrosis, non-cystic fibrosis bronchiectasis, exacerbations of chronic obstructive pulmonary disease (COPD) and non-eosinophilic asthma. Initial, stimulatory effects of azithromycin on immune and epithelial cells, involving interactions with phospholipids and Erk1/2, are followed by later modulation of transcription factors AP-1, NFκB, inflammatory cytokine and mucin release. Delayed inhibitory effects on cell function and high lysosomal accumulation accompany disruption of protein and intracellular lipid transport, regulation of surface receptor expression, of macrophage phenotype and autophagy. These later changes underlie many immunomodulatory effects of azithromycin, contributing to resolution of acute infections and reduction of exacerbations in chronic airway diseases. A sub-group of post-transplant bronchiolitis patients appears to be sensitive to azithromycin, as may be patients with severe sepsis. Other promising indications include chronic prostatitis and periodontitis, but weak activity in malaria is unlikely to prove crucial. Long-term administration of azithromycin must be balanced against the potential for increased bacterial resistance. Azithromycin has a very good record of safety, but recent reports indicate rare cases of cardiac torsades des pointes in patients at risk.

Impairment of lysosomal functions by azithromycin and chloroquine contributes to anti-inflammatory phenotype

Azithromycin and chloroquine have been shown to exhibit anti-inflammatory activities in a number of cellular systems, but the mechanisms of these activities have still not been clarified unequivocally. Since both drugs are cationic, accumulate in acidic cellular compartments and bind to phospholipids with a consequent increase in lysosomal pH and induce phospholipidosis, we examined the relevance of these common properties to their anti-inflammatory activities. We compared also these effects with effects of concanamycin A, compound which inhibits acidification of lysosomes. All three compounds increased lysosomal pH, accumulation of autophagic vacuoles and ubiquitinated proteins and impaired recycling of TLR4 receptor with consequences in downstream signaling in LPS-stimulated J774A.1 cells. Azithromycin and chloroquine additionally inhibited arachidonic acid release and prostaglandin E2 synthesis. Therefore, impairment of lysosomal functions by azithromycin and chloroquine deregulate TLR4 recycling and signaling and phospholipases activation and lead to anti-inflammatory phenotype in LPS-stimulated J774A.1 cells.