Association Between Fluoroquinolones and Major Adverse Cardiovascular Events: A Systematic Review

Fluoroquinolones (FQs) are routinely administered antibiotics that have demonstrated an increased propensity to cause major adverse cardiovascular events (MACE). We conducted a systematic review aimed to investigate the association between FQ usage and the risk of MACE. A comprehensive literature search was conducted using PubMed, Scopus, and the Cochrane Library from inception to September 2023 to retrieve studies comparing FQ administration with placebo and reporting the occurrence of MACE. Relevant studies that explored the occurrence of MACE, defined as "acute myocardial infarction, stroke, cardiovascular mortality, arrhythmia, or heart failure" with FQ usage were eligible for inclusion. Four studies with a total of 42,808 patients were included. Levofloxacin, moxifloxacin, and gatifloxacin were observed to have an increased propensity to cause MACE, particularly arrhythmias, whereas ciprofloxacin was associated with the lowest risk of causing MACE. Despite the methodological diversity in the included studies, this systematic review uncovered a consistent trend of heightened likelihood of MACE with FQ administration across studies, suggesting that elevated serum concentrations of some FQs may correlate with higher risks of MACE development. This systematic review emphasizes the need for cautious administration of FQs, particularly in patients with a preexisting cardiovascular condition. Routine cardiac monitoring using electrocardiograms is warranted for patients on high doses of FQs to preemptively detect the development of MACE, particularly arrhythmias.

Antibiotics as immunomodulators: a potential pharmacologic approach for ARDS treatment

First described in the mid-1960s, acute respiratory distress syndrome (ARDS) is a life-threatening form of respiratory failure with an overall mortality rate of approximately 40%. Despite significant advances in the understanding and treatment of ARDS, no substantive pharmacologic therapy has proven to be beneficial, and current management continues to be primarily supportive. Beyond their antibacterial activity, several antibiotics such as macrolides and tetracyclines exert pleiotropic immunomodulatory effects that might be able to rectify the dysregulated inflammatory response present in patients with ARDS. This review aims to provide an overview of preclinical and clinical studies that describe the immunomodulatory effects of antibiotics in ARDS. Moreover, the underlying mechanisms of their immunomodulatory properties will be discussed. Further studies are necessary to investigate their full therapeutic potential and to identify ARDS phenotypes which are most likely to benefit from their immunomodulatory effects.

Nanomedicine to advance the treatment of bacteria-induced acute lung injury

Bacteria-induced acute lung injury (ALI) is associated with a high mortality rate due to the lack of an effective treatment. Patients often rely on supportive care such as low tidal volume ventilation to alleviate the symptoms. Nanomedicine has recently received much attention owing to its premium benefits of delivering drugs in a sustainable and controllable manner while minimizing the potential side effects. It can effectively improve the prognosis of bacteria-induced ALI through targeted delivery of drugs, regulation of multiple inflammatory pathways, and combating antibiotic resistance. Hence, in this review, we first discuss the pathogenesis of ALI and its potential therapeutics. In particular, the state-of-the-art nanomedicines for the treatment of bacteria-induced ALI are highlighted, including their administration routes, in vivo distribution, and clearance. Furthermore, the available bacteria-induced ALI animal models are also summarized. In the end, future perspectives of nanomedicine for ALI treatment are proposed.

A biomathematical model of immune response and barrier function in mice with pneumococcal lung infection

Pneumonia is one of the leading causes of death worldwide. The course of the disease is often highly dynamic with unforeseen critical deterioration within hours in a relevant proportion of patients. Besides antibiotic treatment, novel adjunctive therapies are under development. Their additive value needs to be explored in preclinical and clinical studies and corresponding therapy schedules require optimization prior to introduction into clinical practice. Biomathematical modeling of the underlying disease and therapy processes might be a useful aid to support these processes. We here propose a biomathematical model of murine immune response during infection with Streptococcus pneumoniae aiming at predicting the outcome of different treatment schedules. The model consists of a number of non-linear ordinary differential equations describing the dynamics and interactions of the pulmonal pneumococcal population and relevant cells of the innate immune response, namely alveolar- and inflammatory macrophages and neutrophils. The cytokines IL-6 and IL-10 and the chemokines CCL2, CXCL1 and CXCL5 are considered as major mediators of the immune response. We also model the invasion of peripheral blood monocytes, their differentiation into macrophages and bacterial penetration through the epithelial barrier causing blood stream infections. We impose therapy effects on this system by modelling antibiotic therapy and treatment with the novel C5a-inactivator NOX-D19. All equations are derived by translating known biological mechanisms into equations and assuming appropriate response kinetics. Unknown model parameters were determined by fitting the predictions of the model to time series data derived from mice experiments with close-meshed time series of state parameters. Parameter fittings resulted in a good agreement of model and data for the experimental scenarios. The model can be used to predict the performance of alternative schedules of combined antibiotic and NOX-D19 treatment. We conclude that we established a comprehensive biomathematical model of pneumococcal lung infection, immune response and barrier function in mice allowing simulations of new treatment schedules. We aim to validate the model on the basis of further experimental data. We also plan the inclusion of further novel therapy principles and the translation of the model to the human situation in the near future.

Mesenchymal stem cells alleviate hydrochloric acid-induced lung injury through suppression of inflammation, oxidative stress and apoptosis in comparison to moxifloxacin and sildenafil

Introduction

Acute lung injury (ALI) is a severe life-threatening disease causing uncontrolled pulmonary inflammation and oxidative damage. There are still no effective therapies for this disease. The aim of this study was to evaluate the protective role of mesenchymal stem cells, moxifloxacin, sildenafil or a combination of moxifloxacin and sildenafil against hydrochloric Acid (HCl) - induced ALI.

Methods

HCl or saline was injected intra-tracheally and after 2 h, moxifloxacin, sildenafil, moxifloxacin + sildenafil or mesenchymal stem cells were injected. After 7 days, rats were sacrificed for evaluation of the blood chemistry and inflammation via determination of the level of oxidative stress markers, apoptosis and the histopathological alterations by H&E.

Results

In HCl-injected rats, there were a significant increase in total white blood cells (WBCs), lymphocytes, malondialdehyde (MDA) and caspase-3 gene expression. Also, there were a significant decrease in superoxide dismutase (SOD), catalase (CAT), reduced glutathione (GSH) and Hemeoxygenase-1 (HO-1) gene expression in lung tissue. On the other hand, treatment of lung injured rats with mesenchymal stem cell, moxifloxacin, sildenafil or a combination of moxifloxacin and sildenafil showed a significant decrease in WBCs and lymphocytes and ameliorated the histopathological changes. MDA level in lung tissue was only significantly lowered in rats treated with moxifloxacin alone or in combination with sildenafil or MSCs. GSH was just increased in rats treated with moxifloxacin, sildenafil or with MSCs. Antioxidant parameters and gene expression of HO-1 and caspase-3 were significantly modulated in rats treated with MSCs.

Conclusion

MSCs ameliorated the toxic effects of HCl through their ability to decrease inflammation, oxidative stress, and apoptosis in acute lung injury.

Clinically relevant model of pneumococcal pneumonia, ARDS, and nonpulmonary organ dysfunction in mice

Pneumonia is responsible for more deaths in the United States than any other infectious disease. Severe pneumonia is a common cause of acute respiratory failure and acute respiratory distress syndrome (ARDS). Despite the introduction of effective antibiotics and intensive supportive care in the 20th century, death rates from community-acquired pneumonia among patients in the intensive care unit remain as high as 35%. Beyond antimicrobial treatment, no targeted molecular therapies have yet proven effective, highlighting the need for additional research. Despite some limitations, small animal models of pneumonia and the mechanistic insights they produce are likely to continue to play an important role in generating new therapeutic targets. Here we describe the development of an innovative mouse model of pneumococcal pneumonia developed for enhanced clinical relevance. We first reviewed the literature of small animal models of bacterial pneumonia that incorporated antibiotics. We then did a series of experiments in mice in which we systematically varied the pneumococcal inoculum and the timing of antibiotics while measuring systemic and lung-specific end points, producing a range of models that mirrors the spectrum of pneumococcal lung disease in patients, from mild self-resolving infection to severe pneumonia refractory to antibiotics. A delay in antibiotic treatment resulted in ongoing inflammation and renal and hepatic dysfunction despite effective bacterial killing. The addition of fluid resuscitation to the model improved renal function but worsened the severity of lung injury based on direct measurements of pulmonary edema and lung compliance, analogous to patients with pneumonia and sepsis who develop ARDS following fluid administration.

Optimising experimental research in respiratory diseases: an ERS statement

Experimental models are critical for the understanding of lung health and disease and are indispensable for drug development. However, the pathogenetic and clinical relevance of the models is often unclear. Further, the use of animals in biomedical research is controversial from an ethical perspective.The objective of this task force was to issue a statement with research recommendations about lung disease models by facilitating in-depth discussions between respiratory scientists, and to provide an overview of the literature on the available models. Focus was put on their specific benefits and limitations. This will result in more efficient use of resources and greater reduction in the numbers of animals employed, thereby enhancing the ethical standards and translational capacity of experimental research.The task force statement addresses general issues of experimental research (ethics, species, sex, age, ex vivo and in vitro models, gene editing). The statement also includes research recommendations on modelling asthma, chronic obstructive pulmonary disease, pulmonary fibrosis, lung infections, acute lung injury and pulmonary hypertension.The task force stressed the importance of using multiple models to strengthen validity of results, the need to increase the availability of human tissues and the importance of standard operating procedures and data quality.

Spectrum of pathogen- and model-specific histopathologies in mouse models of acute pneumonia

Pneumonia may be caused by a wide range of pathogens and is considered the most common infectious cause of death in humans. Murine acute lung infection models mirror human pathologies in many aspects and contribute to our understanding of the disease and the development of novel treatment strategies. Despite progress in other fields of tissue imaging, histopathology remains the most conclusive and practical read out tool for the descriptive and semiquantitative evaluation of mouse pneumonia and therapeutic interventions. Here, we systematically describe and compare the distinctive histopathological features of established models of acute pneumonia in mice induced by Streptococcus (S.) pneumoniae, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Legionella pneumophila, Escherichia coli, Middle East respiratory syndrome (MERS) coronavirus, influenza A virus (IAV) and superinfection of IAV-incuced pneumonia with S. pneumoniae. Systematic comparisons of the models revealed striking differences in the distribution of lesions, the characteristics of pneumonia induced, principal inflammatory cell types, lesions in adjacent tissues, and the detectability of the pathogens in histological sections. We therefore identified core criteria for each model suitable for practical semiquantitative scoring systems that take into account the pathogen- and model-specific patterns of pneumonia. Other critical factors that affect experimental pathologies are discussed, including infectious dose, time kinetics, and the genetic background of the mouse strain. The substantial differences between the model-specific pathologies underscore the necessity of pathogen- and model-adapted criteria for the comparative quantification of experimental outcomes. These criteria also allow for the standardized validation and comparison of treatment strategies in preclinical models.

Vasculotide reduces pulmonary hyperpermeability in experimental pneumococcal pneumonia

Background

Community-acquired pneumonia (CAP) is a significant cause of morbidity and mortality worldwide. Despite effective antimicrobial therapy, CAP can induce pulmonary endothelial hyperpermeability resulting in life-threatening lung failure due to an exaggerated host-pathogen interaction. Treatment of acute lung injury is mainly supportive because key elements of inflammation-induced barrier disruption remain undetermined. Angiopoietin-1 (Ang-1)-mediated Tie2 activation reduces, and the Ang-1 antagonist Ang-2 increases, inflammation and endothelial permeability in sepsis. Vasculotide (VT) is a polyethylene glycol-clustered Tie2-binding peptide that mimics the actions of Ang-1. The aim of our study was to experimentally test whether VT is capable of diminishing pneumonia-induced lung injury.

Methods

VT binding and phosphorylation of Tie2 were analyzed using tryptophan fluorescence spectroscopy and phospho-Tie-2 enzyme-linked immunosorbent assay. Human and murine lung endothelial cells were investigated by immunofluorescence staining and electric cell-substrate impedance sensing. Pulmonary hyperpermeability was quantified in VT-pretreated, isolated, perfused, and ventilated mouse lungs stimulated with the pneumococcal exotoxin pneumolysin (PLY). Furthermore, Streptococcus pneumoniae-infected mice were therapeutically treated with VT.

Results

VT showed dose-dependent binding and phosphorylation of Tie2. Pretreatment with VT protected lung endothelial cell monolayers from PLY-induced disruption. In isolated mouse lungs, VT decreased PLY-induced pulmonary permeability. Likewise, therapeutic treatment with VT of S. pneumoniae-infected mice significantly reduced pneumonia-induced hyperpermeability. However, effects by VT on the pulmonary or systemic inflammatory response were not observed.

Conclusions

VT promoted pulmonary endothelial stability and reduced lung permeability in different models of pneumococcal pneumonia. Thus, VT may provide a novel therapeutic perspective for reduction of permeability in pneumococcal pneumonia-induced lung injury.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-017-1851-6) contains supplementary material, which is available to authorized users.

Fluoroquinolones increase the risk of serious arrhythmias: A systematic review and meta-analysis

BACKGROUND

The association between oral fluoroquinolones (FQs) usage and risk of severe arrhythmia-related events (ventricular arrhythmias and sudden cardiac death) remains controversial. Therefore we aimed to quantify this association and to evaluate the effects of FQs on adverse cardiovascular (CV) outcomes.

METHODS

We retrieved data from the Cochrane Collaboration, PubMed, and China National Knowledge Infrastructure (CNKI) databases until August 2017. The studies that reported relative risk (RR) estimates with 95% confidence intervals (CIs) for the associations of interest were included. Data were extracted from the eligible articles, and we used a random effects model to calculate the effect estimates.

RESULTS

Of the 16 studies that were included, 7 studies included serious arrhythmias, 3 studies included CV death, and 11 studies included all-cause death. The pooled RRs of FQs use were: 2.29 (95% CI: 1.20-4.36, P = .01) for serious arrhythmias; 1.60 (95% CI: 1.17-2.20, P = .004) for CV death; and 1.02 (95% CI: 0.76-1.37, P = .92) for all-cause death. The RRs associated with serious arrhythmias were 6.27 for gatifloxacin, 4.20 for moxifloxacin, 1.73 for ciprofloxacin, and 1.41 for levofloxacin. Current FQs users showed an increased risk of serious arrhythmias in the subgroup analysis. Treatment with FQs is associated with an absolute risk increase of 160 additional sudden deaths or ventricular arrhythmias, and 43 additional CV deaths per 1 million treatment courses.

CONCLUSION

The use of FQs could increase the risk of serious arrhythmias and CV death but not increase or all-cause death. Moreover, moxifloxacin and levofloxacin showed a higher risk of serious arrhythmias.

Human lung ex vivo infection models

Pneumonia is counted among the leading causes of death worldwide. Viruses, bacteria and pathogen-related molecules interact with cells present in the human alveolus by numerous, yet poorly understood ways. Traditional cell culture models little reflect the cellular composition, matrix complexity and three-dimensional architecture of the human lung. Integrative animal models suffer from species differences, which are of particular importance for the investigation of zoonotic lung diseases. The use of cultured ex vivo infected human lung tissue may overcome some of these limitations and complement traditional models. The present review gives an overview of common bacterial lung infections, such as pneumococcal infection and of widely neglected pathogens modeled in ex vivo infected lung tissue. The role of ex vivo infected lung tissue for the investigation of emerging viral zoonosis including influenza A virus and Middle East respiratory syndrome coronavirus is discussed. Finally, further directions for the elaboration of such models are revealed. Overall, the introduced models represent meaningful and robust methods to investigate principles of pathogen-host interaction in original human lung tissue.

Therapeutic strategies in pneumonia: going beyond antibiotics

Dysregulation of the innate immune system drives lung injury and its systemic sequelae due to breakdown of vascular barrier function, harmful hyperinflammation and microcirculatory failure, which contribute to the unfavourable outcome of patients with severe pneumonia. A variety of promising therapeutic targets have been identified and numerous innovative therapeutic approaches demonstrated to improve lung injury in experimental preclinical studies. However, at present specific preventive or curative strategies for the treatment of lung failure in pneumonia in addition to antibiotics are still missing. The aim of this mini-review is to give a short overview of some, but not all, adjuvant therapeutic strategies for pneumonia and its most important complications, sepsis and acute respiratory distress syndrome, and briefly discuss future perspectives.

A Biomathematical Model of Pneumococcal Lung Infection and Antibiotic Treatment in Mice

Pneumonia is considered to be one of the leading causes of death worldwide. The outcome depends on both, proper antibiotic treatment and the effectivity of the immune response of the host. However, due to the complexity of the immunologic cascade initiated during infection, the latter cannot be predicted easily. We construct a biomathematical model of the murine immune response during infection with pneumococcus aiming at predicting the outcome of antibiotic treatment. The model consists of a number of non-linear ordinary differential equations describing dynamics of pneumococcal population, the inflammatory cytokine IL-6, neutrophils and macrophages fighting the infection and destruction of alveolar tissue due to pneumococcus. Equations were derived by translating known biological mechanisms and assuming certain response kinetics. Antibiotic therapy is modelled by a transient depletion of bacteria. Unknown model parameters were determined by fitting the predictions of the model to data sets derived from mice experiments of pneumococcal lung infection with and without antibiotic treatment. Time series of pneumococcal population, debris, neutrophils, activated epithelial cells, macrophages, monocytes and IL-6 serum concentrations were available for this purpose. The antibiotics Ampicillin and Moxifloxacin were considered. Parameter fittings resulted in a good agreement of model and data for all experimental scenarios. Identifiability of parameters is also estimated. The model can be used to predict the performance of alternative schedules of antibiotic treatment. We conclude that we established a biomathematical model of pneumococcal lung infection in mice allowing predictions regarding the outcome of different schedules of antibiotic treatment. We aim at translating the model to the human situation in the near future.