Macrolide therapy is associated with reduced mortality in acute respiratory distress syndrome (ARDS) patients

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.

Translational medicine for acute lung injury

Acute lung injury (ALI) is a complex disease with numerous causes. This review begins with a discussion of disease development from direct or indirect pulmonary insults, as well as varied pathogenesis. The heterogeneous nature of ALI is then elaborated upon, including its epidemiology, clinical manifestations, potential biomarkers, and genetic contributions. Although no medication is currently approved for this devastating illness, supportive care and pharmacological intervention for ALI treatment are summarized, followed by an assessment of the pathophysiological gap between human ALI and animal models. Lastly, current research progress on advanced nanomedicines for ALI therapeutics in preclinical and clinical settings is reviewed, demonstrating new opportunities towards developing an effective treatment for ALI.

Application of anti-inflammatory treatment in two different ovine Acute Respiratory Distress Syndrome injury models: a preclinical randomized intervention study

Whilst the presence of 2 subphenotypes among the heterogenous Acute Respiratory Distress Syndrome (ARDS) population is becoming clinically accepted, subphenotype-specific treatment efficacy has yet to be prospectively tested. We investigated anti-inflammatory treatment in different ARDS models in sheep, previously shown similarities to human ARDS subphenotypes, in a preclinical, randomized, blinded study. Thirty anesthetized sheep were studied up to 48 h and randomized into: (a) OA: oleic acid (n = 15) and (b) OA-LPS: oleic acid and subsequent lipopolysaccharide (n = 15) to achieve a PaO2/FiO2 ratio of < 150 mmHg. Then, animals were randomly allocated to receive treatment with methylprednisolone or erythromycin or none. Assessed outcomes were oxygenation, pulmonary mechanics, hemodynamics and survival. All animals reached ARDS. Treatment with methylprednisolone, but not erythromycin, provided the highest therapeutic benefit in Ph2 animals, leading to a significant increase in PaO2/FiO2 ratio by reducing pulmonary edema, dead space ventilation and shunt fraction. Animals treated with methylprednisolone displayed a higher survival up to 48 h than all others. In animals treated with erythromycin, there was no treatment benefit regarding assessed physiological parameters and survival in both phenotypes. Treatment with methylprednisolone improves oxygenation and survival, more so in ovine phenotype 2 which resembles the human hyperinflammatory subphenotype.

Effect of erythromycin on mortality and the host response in critically ill patients with sepsis: a target trial emulation

BACKGROUND

Immunomodulatory therapies that improve the outcome of sepsis are not available. We sought to determine whether treatment of critically ill patients with sepsis with low-dose erythromycin-a macrolide antibiotic with broad immunomodulatory effects-decreased mortality and ameliorated underlying disease pathophysiology.

METHODS

We conducted a target trial emulation, comparing patients with sepsis admitted to two intensive care units (ICU) in the Netherlands for at least 72 h, who were either exposed or not exposed during this period to treatment with low-dose erythromycin (up to 600 mg per day, administered as a prokinetic agent) but no other macrolides. We used two common propensity score methods (matching and inverse probability of treatment weighting) to deal with confounding by indication and subsequently used Cox regression models to estimate the treatment effect on the primary outcome of mortality rate up to day 90. Secondary clinical outcomes included change in SOFA, duration of mechanical ventilation and the incidence of ICU-acquired infections. We used linear mixed models to assess differences in 15 host response biomarkers reflective of key pathophysiological processes from admission to day 4.

RESULTS

In total, 235 patients started low-dose erythromycin treatment, 470 patients served as controls. Treatment started at a median of 38 [IQR 25-52] hours after ICU admission for a median of 5 [IQR 3-8] total doses in the first course. Matching and weighting resulted in populations well balanced for proposed confounders. We found no differences between patients treated with low-dose erythromycin and control subjects in mortality rate up to day 90: matching HR 0.89 (95% CI 0.64-1.24), weighting HR 0.95 (95% CI 0.66-1.36). There were no differences in secondary clinical outcomes. The change in host response biomarker levels from admission to day 4 was similar between erythromycin-treated and control subjects.

CONCLUSION

In this target trial emulation in critically ill patients with sepsis, we could not demonstrate an effect of treatment with low-dose erythromycin on mortality, secondary clinical outcomes or host response biomarkers.

Azithromycin and Major Adverse Kidney Events in Critically Ill Patients With Sepsis-Associated Acute Kidney Injury

BACKGROUND

Sepsis-associated acute kidney injury (SA-AKI) is associated with significant morbidity and mortality. Immune dysregulation is a hallmark of sepsis, with important contributions to organ dysfunction including injury and repair mechanisms in AKI. Macrolide antibiotics, such as azithromycin, have previously demonstrated in preclinical models a myriad of immunomodulatory effects that may benefit critically ill patients with SA-AKI. The aim of this study was to determine if early receipt of azithromycin in SA-AKI is associated with a reduction in major adverse kidney events (MAKE) at hospital discharge.

METHODS

This was a single center, retrospective cohort study of critically ill adult patients with SA-AKI. Early exposure to azithromycin was defined as receipt of one or more doses within 48 h of a hospital admission with SA-AKI. The primary outcome of MAKE assessed at hospital discharge was the composite of death, requirement for kidney replacement therapy, or a decline in estimated glomerular filtration rate of 25% or more. Multivariable logistic regression was used to account for potential confounders in the assessment.

RESULTS

Of 737 included patients with SA-AKI, 152 (20.6%) received azithromycin. Patients that received early azithromycin were less likely to experience MAKE at hospital discharge when compared to those patients not receiving azithromycin: 38.8% versus 48.4% (P = 0.035). In multivariable logistic regression, receipt of azithromycin was independently associated with a decreased odds of MAKE at hospital discharge (aOR 0.62, 95% CI 0.41-0.93).

CONCLUSIONS

Early exposure to azithromycin in SA-AKI is independently associated with lower odds of MAKE at hospital discharge.

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.

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.

Immunomodulation of endothelial cells induced by macrolide therapy in a model of septic stimulation

Objectives

Sepsis is defined as the host's inflammatory response to a life‐threatening infection. The endothelium is implicated in immunoregulation during sepsis. Macrolides have been proposed to display immunomodulatory properties. The goal of this study was to analyze whether macrolides can exert immunomodulation of endothelial cells (ECs) in an experimental model of sepsis.

Methods

Human ECs were stimulated by proinflammatory cytokines and lipopolysaccharide before exposure to macrolides. ECs phenotypes were analyzed by flow cytometry. Cocultures of ECs and peripheral blood mononuclear cells (PBMCs) were performed to study the ECs ability to alter T‐cell viability and differentiation in the presence of macrolides. Soluble factor production was assessed.

Results

ECs act as non‐professional antigen presenting cells and expressed human leukocyte antigen (HLA) antigens, the adhesion molecules CD54, CD106, and the coinhibitory molecule CD274 after septic stimulation. Incubation with macrolides induced a significant decrease of HLA class I and HLA class II HLA‐DR on septic‐stimulated ECs, but did not alter either CD54, CD106, nor CD274 expression. Interleukin‐6 (IL‐6) and IL‐8 production by stimulated ECs were unaltered by incubation with macrolides, whereas Clarithromycin exposure significantly decreased IL‐6 gene expression. In cocultures of septic ECs with PBMCs, neither the proportion of CD4 ⁺, CD8 ⁺T nor their viability was altered by macrolides. T‐helper lymphocyte subsets Th1, Th17, and Treg polarization by stimulated ECs were unaltered by macrolides.

Conclusion

This study reports phenotypic and gene expression changes in septic‐stimulated ECs exposed to macrolides, without resulting in altered immunogenicity of ECs in co‐cultures with PBMCs. In vivo studies may help to further understand the impact of macrolide therapy on ECs immune homeostasis during sepsis.

Anti-inflammatory activity of lefamulin versus azithromycin and dexamethasone in vivo and in vitro in a lipopolysaccharide-induced lung neutrophilia mouse model

Several antibiotics demonstrate both antibacterial and anti-inflammatory/immunomodulatory activities and are used to treat inflammatory pulmonary disorders. Lefamulin is a pleuromutilin antibiotic approved to treat community-acquired bacterial pneumonia (CABP). This study evaluated lefamulin anti-inflammatory effects in vivo and in vitro in a lipopolysaccharide-induced lung neutrophilia model in which mouse airways were challenged with intranasal lipopolysaccharide. Lefamulin and comparators azithromycin and dexamethasone were administered 30min before lipopolysaccharide challenge; neutrophil infiltration into BALF and inflammatory mediator induction in lung homogenates were measured 4h postchallenge. Single subcutaneous lefamulin doses (10‒140mg/kg) resulted in dose-dependent reductions of BALF neutrophil cell counts, comparable to or more potent than subcutaneous azithromycin (10‒100mg/kg) and oral/intraperitoneal dexamethasone (0.5/1mg/kg). Lipopolysaccharide-induced pro-inflammatory cytokine (TNF-α, IL-6, IL-1β, and GM-CSF), chemokine (CXCL-1, CXCL-2, and CCL-2), and MMP-9 levels were significantly and dose-dependently reduced in mouse lung tissue with lefamulin; effects were comparable to or more potent than with dexamethasone or azithromycin. Pharmacokinetic analyses confirmed exposure-equivalence of 30mg/kg subcutaneous lefamulin in mice to a single clinical lefamulin dose to treat CABP in humans (150mg intravenous/600mg oral). In vitro, neither lefamulin nor azithromycin had any relevant influence on lipopolysaccharide-induced cytokine/chemokine levels in J774.2 mouse macrophage or human peripheral blood mononuclear cell supernatants, nor were any effects observed on IL-8‒induced human neutrophil chemotaxis. These in vitro results suggest that impediment of neutrophil infiltration by lefamulin in vivo may not occur through direct interaction with macrophages or neutrophilic chemotaxis. This is the first study to demonstrate inhibition of neutrophilic lung infiltration and reduction of pro-inflammatory cytokine/chemokine concentrations by clinically relevant lefamulin doses. This anti-inflammatory activity may be beneficial in patients with acute respiratory distress syndrome, cystic fibrosis, or severe inflammation-mediated lung injury, similar to glucocorticoid (eg, dexamethasone) activity. Future lefamulin anti-inflammatory/immunomodulatory activity studies are warranted to further elucidate mechanism of action and evaluate clinical implications.

Could Azithromycin Be Part of Pseudomonas aeruginosa Acute Pneumonia Treatment?

Azithromycin (AZM) is a 15-membered-ring macrolide that presents a broad-spectrum antimicrobial activity against Gram-positive bacteria and atypical microorganisms but suffers from a poor diffusion across the outer-membrane of Gram-negative bacilli, including Pseudomonas aeruginosa (PA). However, AZM has demonstrated clinical benefits in patients suffering from chronic PA respiratory infections, especially cystic fibrosis patients. Since the rise of multidrug-resistant PA has led to a growing need for new therapeutic options, this macrolide has been proposed as an adjunctive therapy. Clinical trials assessing AZM in PA acute pneumonia are scarce. However, a careful examination of the available literature provides good rationales for its use in that context. In fact, 14- and 15-membered-ring macrolides have demonstrated immunomodulatory and immunosuppressive effects that could be of major interest in the management of acute illness. Furthermore, growing evidence supports a downregulation of PA virulence dependent on direct interaction with the ribosomes, and based on the modulation of several key regulators from the Quorum Sensing network. First highlighted in vitro, these interesting properties of AZM have subsequently been confirmed in the animal models. In this review, we systematically analyzed the literature regarding AZM immunomodulatory and anti-PA effects. In vitro and in vivo studies, as well as clinical trials were reviewed, looking for rationales for AZM use in PA acute pneumonia.

Between-trial heterogeneity in ARDS research

Purpose

Most randomized controlled trials (RCTs) in patients with acute respiratory distress syndrome (ARDS) revealed indeterminate or conflicting study results. We aimed to systematically evaluate between-trial heterogeneity in reporting standards and trial outcome.

Methods

A systematic review of RCTs published between 2000 and 2019 was performed including adult ARDS patients receiving lung-protective ventilation. A random-effects meta-regression model was applied to quantify heterogeneity (non-random variability) and to evaluate trial and patient characteristics as sources of heterogeneity.

Results

In total, 67 RCTs were included. The 28-day control-group mortality rate ranged from 10 to 67% with large non-random heterogeneity (I² = 88%, p < 0.0001). Reported baseline patient characteristics explained some of the outcome heterogeneity, but only six trials (9%) reported all four independently predictive variables (mean age, mean lung injury score, mean plateau pressure and mean arterial pH). The 28-day control group mortality adjusted for patient characteristics (i.e. the residual heterogeneity) ranged from 18 to 45%. Trials with significant benefit in the primary outcome reported a higher control group mortality than trials with an indeterminate outcome or harm (mean 28-day control group mortality: 44% vs. 28%; p = 0.001).

Conclusion

Among ARDS RCTs in the lung-protective ventilation era, there was large variability in the description of baseline characteristics and significant unexplainable heterogeneity in 28-day control group mortality. These findings signify problems with the generalizability of ARDS research and underline the urgent need for standardized reporting of trial and baseline characteristics.

Supplementary Information

The online version of this article (10.1007/s00134-021-06370-w) contains supplementary material, which is available to authorized users.

The discovery of biological subphenotypes in ARDS: a novel approach to targeted medicine?

The acute respiratory distress syndrome (ARDS) is a severe lung disorder with a high morbidity and mortality which affects all age groups. Despite active research with intense, ongoing attempts in developing pharmacological agents to treat ARDS, its mortality rate remains unaltered high and treatment is still only supportive. Over the years, there have been many attempts to identify meaningful subgroups likely to react differently to treatment among the heterogenous ARDS population, most of them unsuccessful. Only recently, analysis of large ARDS cohorts from randomized controlled trials have identified the presence of distinct biological subphenotypes among ARDS patients: a hypoinflammatory (or uninflamed; named P1) and a hyperinflammatory (or reactive; named P2) subphenotype have been proposed and corroborated with existing retrospective data. The hyperinflammatory subphenotyope was clearly associated with shock state, metabolic acidosis, and worse clinical outcomes. Core features of the respective subphenotypes were identified consistently in all assessed cohorts, independently of the studied population, the geographical location, the study design, or the analysis method. Additionally and clinically even more relevant treatment efficacies, as assessed retrospectively, appeared to be highly dependent on the respective subphenotype. This discovery launches a promising new approach to targeted medicine in ARDS. Even though it is now widely accepted that each ARDS subphenotype has distinct functional, biological, and mechanistic differences, there are crucial gaps in our knowledge, hindering the translation to bedside application. First of all, the underlying driving biological factors are still largely unknown, and secondly, there is currently no option for fast and easy identification of ARDS subphenotypes. This narrative review aims to summarize the evidence in biological subphenotyping in ARDS and tries to point out the current issues that will need addressing before translation of biological subohenotypes into clinical practice will be possible.

Two Cases of Severe COVID-19 Pneumonia Effectively Treated with Extracorporeal Membrane Oxygenation in Addition to Favipiravir and Corticosteroid

Case 1: A 65-year-old man with novel coronavirus infection (COVID-19) complicated with acute respiratory failure. On admission, the patient was started on favipiravir and corticosteroid. However, due to a lack of significant improvement, he was introduced to mechanical ventilation and extracorporeal membrane oxygenation (ECMO). Although iliopsoas hematoma occurred as a complication, the patient recovered. Case 2: A 49-year-old man with COVID-19 had been started on favipiravir and corticosteroid. Due to progressive respiratory failure, the patient underwent mechanical ventilation and ECMO. The patient recovered without complications. We successfully treated these severe cases with a multimodal combination of pharmacological and non-pharmacological supportive therapy.

Inflammasome activation in acute lung injury

Inflammasomes are multiprotein complexes tasked with sensing endogenous or exogenous inflammatory signals and integrating this signal into a downstream response. Inflammasome activation has been implicated in a variety of pulmonary diseases, including pulmonary hypertension, bacterial pneumonia, COPD, and asthma. Of increasing interest is the contribution of inflammasome activation in the context of acute lung injury/acute respiratory distress syndrome (ALI/ARDS). Inflammasome activation in both the lung parenchyma and resident immune cells generates intereukin-1β (IL-1β) and IL-18, both of which drive the cascade of lung inflammation forward. Blockade of these responses has been shown to be beneficial in animal models and is a focus of translational research in the field. In this review, we will discuss the assembly and regulation of inflammasomes during lung inflammation, highlighting therapeutically viable effector steps. We will examine the importance of IL-1β and IL-18, two key products of inflammasome activation, in ALI, as well as the contribution of the pulmonary endothelial cell to this process. Finally, we will explore translational research moving toward anti-inflammasome therapies for ALI/ARDS and speculate toward future directions for the field.

Hydroxychloroquine vs. Azithromycin for Hospitalized Patients with COVID-19 (HAHPS): Results of a Randomized, Active Comparator Trial

RATIONALE

The COVID-19 pandemic struck an immunologically naïve, globally interconnected population. In the face of a new infectious agent causing acute respiratory failure for which there were no known effective therapies, rapid, often pragmatic trials were necessary to evaluate potential treatments, frequently starting with medications that are already marketed for other indications. Early in the pandemic, hydroxychloroquine and azithromycin were two such candidates.

OBJECTIVE

Assess the relative efficacy of hydroxychloroquine and azithromycin among hospitalized patients with COVID-19.

METHODS

We performed a randomized clinical trial of hydroxychloroquine vs. azithromycin among hospitalized patients with COVID-19. Treatment was 5 days of study medication. The primary endpoint was the COVID Ordinal Outcomes scale at day 14. Secondary endpoints included hospital-, ICU-, and ventilator-free days at day 28. The trial was stopped early after enrollment of 85 patients when a separate clinical trial concluded that a clinically important effect of hydroxychloroquine over placebo was definitively excluded. Comparisons were made a priori using a proportional odds model from a Bayesian perspective.

RESULTS

We enrolled 85 patients at 13 hospitals over 11 weeks. Adherence to study medication was high. The estimated odds ratio for less favorable status on the ordinal scale for hydroxychloroquine vs. azithromycin from the primary analysis was 1.07, with a 95% credible interval from 0.63 to 1.83 with a posterior probability of 60% that hydroxychloroquine was worse than azithryomycin. Secondary outcomes displayed a similar, slight preference for azithromycin over hydroxychloroquine. QTc prolongation was rare and did not differ between groups. The twenty safety outcomes were similar between arms with the possible exception of post-randomization onset acute kidney injury, which was more common with hydroxychloroquine (15% vs. 0%). Patients in the hydroxychloroquine arm received remdesivir more often than in the azithromycin arm (19% vs. 2%). There was no apparent association between remdesivir use and acute kidney injury.

CONCLUSIONS

While early termination limits the precision of our results, we found no suggestion of substantial efficacy for hydroxychloroquine over azithromycin. Acute kidney injury may be more common with hydroxychloroquine than azithromycin, although this may be due to the play of chance. Differential use of remdesivir may have biased our results in favor of hydroxychloroquine. Our results are consistent with conclusions from other trials that hydroxychloroquine cannot be recommended for inpatients with COVID-19; azithromycin may merit additional investigation.

CLINICAL TRIAL REGISTRATION

This trial was prospectively registered (NCT04329832) before enrollment of the first patient.

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.

Subphenotypes in critical care: translation into clinical practice

Despite progress in the supportive care available for critically ill patients, few advances have been made in the search for effective disease-modifying therapeutic options. The fact that many trials in critical care medicine have not identified a treatment benefit is probably due, in part, to the underlying heterogeneity of critical care syndromes. Numerous approaches have been proposed to divide populations of critically ill patients into more meaningful subgroups (subphenotypes), some of which might be more useful than others. Subclassification systems driven by clinical features and biomarkers have been proposed for acute respiratory distress syndrome, sepsis, acute kidney injury, and pancreatitis. Identifying the systems that are most useful and biologically meaningful could lead to a better understanding of the pathophysiology of critical care syndromes and the discovery of new treatment targets, and allow recruitment in future therapeutic trials to focus on predicted responders. This Review discusses proposed subphenotypes of critical illness syndromes and highlights the issues that will need to be addressed to translate subphenotypes into clinical practice.

Hydroxychloroquine versus Azithromycin for Hospitalized Patients with Suspected or Confirmed COVID-19 (HAHPS). Protocol for a Pragmatic, Open-Label, Active Comparator Trial

Coronavirus disease (COVID-19) is a potentially fatal illness with no proven therapy beyond excellent supportive care. Treatments are urgently sought. Adaptations to traditional trial logistics and design to allow rapid implementation, evaluation of trials within a global trials context, flexible interim monitoring, and access outside traditional research hospitals (even in settings where formal placebos are unavailable) may be helpful. Thoughtful adaptations to traditional trial designs, especially within the global context of related studies, may also foster collaborative relationships among government, community, and the research enterprise. Here, we describe the protocol for a pragmatic, active comparator trial in as many as 300 patients comparing two current "off-label" treatments for COVID-19-hydroxychloroquine and azithromycin-in academic and nonacademic hospitals in Utah. We developed the trial in response to local pressures for widespread, indiscriminate off-label use of these medications. We used a hybrid Bayesian-frequentist design for interim monitoring to allow rapid, contextual assessment of the available evidence. We also developed an inference grid for interpreting the range of possible results from this trial within the context of parallel trials and prepared for a network meta-analysis of the resulting data. This trial was prospectively registered (ClinicalTrials.gov Identifier: NCT04329832) before enrollment of the first patient.Clinical trial registered with www.clinicaltrials.gov (NCT04329832).

Potential Role of Nrf2 Activators with Dual Antiviral and Anti-Inflammatory Properties in the Management of Viral Pneumonia

The outbreak of coronavirus disease 2019 (COVID-19) pandemic has already caused a huge burden to the global healthcare system, with the death toll reached tens of thousands. Although some antiviral agents were identified and used to inhibit viral replication, the management of cytokine storm is also a critical issue. In this article, we reviewed the literature on drug candidates for severe acute respiratory syndrome (SARS-CoV-1) and provided a brief overview of a class of drugs that exert antiviral and anti-inflammatory effects. These molecules mitigated inflammatory cytokine cascades induced by viral infections via Nrf2 activating capacity and might have additional anti-fibrotic and anti-remodeling properties. Besides, their effects on the regulation of scavenger receptors expression by macrophages may offer some benefits to the pulmonary antibacterial defense system after viral infection. The potential roles of these agents assessed on the basis of the pathophysiology of viral pneumonia and acute respiratory distress syndrome were also discussed. Further research is needed to ascertain whether Nrf2 activators are useful in the management of viral pneumonia.

Adjusting for Disease Severity Across ICUs in Multicenter Studies

Supplemental Digital Content is available in the text.

Objectives:

To compare methods to adjust for confounding by disease severity during multicenter intervention studies in ICU, when different disease severity measures are collected across centers.

Design:

In silico simulation study using national registry data.

Setting:

Twenty mixed ICUs in The Netherlands.

Subjects:

Fifty-five–thousand six-hundred fifty-five ICU admissions between January 1, 2011, and January 1, 2016.

Interventions:

None.

Measurements and Main Results:

To mimic an intervention study with confounding, a fictitious treatment variable was simulated whose effect on the outcome was confounded by Acute Physiology and Chronic Health Evaluation IV predicted mortality (a common measure for disease severity). Diverse, realistic scenarios were investigated where the availability of disease severity measures (i.e., Acute Physiology and Chronic Health Evaluation IV, Acute Physiology and Chronic Health Evaluation II, and Simplified Acute Physiology Score II scores) varied across centers. For each scenario, eight different methods to adjust for confounding were used to obtain an estimate of the (fictitious) treatment effect. These were compared in terms of relative (%) and absolute (odds ratio) bias to a reference scenario where the treatment effect was estimated following correction for the Acute Physiology and Chronic Health Evaluation IV scores from all centers. Complete neglect of differences in disease severity measures across centers resulted in bias ranging from 10.2% to 173.6% across scenarios, and no commonly used methodology—such as two-stage modeling or score standardization—was able to effectively eliminate bias. In scenarios where some of the included centers had (only) Acute Physiology and Chronic Health Evaluation II or Simplified Acute Physiology Score II available (and not Acute Physiology and Chronic Health Evaluation IV), either restriction of the analysis to Acute Physiology and Chronic Health Evaluation IV centers alone or multiple imputation of Acute Physiology and Chronic Health Evaluation IV scores resulted in the least amount of relative bias (0.0% and 5.1% for Acute Physiology and Chronic Health Evaluation II, respectively, and 0.0% and 4.6% for Simplified Acute Physiology Score II, respectively). In scenarios where some centers used Acute Physiology and Chronic Health Evaluation II, regression calibration yielded low relative bias too (relative bias, 12.4%); this was not true if these same centers only had Simplified Acute Physiology Score II available (relative bias, 54.8%).

Conclusions:

When different disease severity measures are available across centers, the performance of various methods to control for confounding by disease severity may show important differences. When planning multicenter studies, researchers should make contingency plans to limit the use of or properly incorporate different disease measures across centers in the statistical analysis.

Understanding Heterogeneity in Biologic Phenotypes of Acute Respiratory Distress Syndrome by Leukocyte Expression Profiles

Rationale: Two biologic phenotypes of acute respiratory distress syndrome (ARDS) have been identified based on plasma protein markers in four previous studies. Objectives: To determine if blood leukocyte gene expression is different between the "reactive" and "uninflamed" phenotype. Methods: This is a new study adding blood leukocyte transcriptomics and bioinformatics analysis to an existing patient cohort of ARDS in patients with sepsis admitted to two ICUs during a 1.5-year period. Canonical pathway analysis was performed. Measurements and Main Results: A total of 210 patients with sepsis and ARDS were included, of whom 128 had a reactive and 82 an uninflamed phenotype. A total of 3,332/11,443 (29%) transcripts were significantly different between the phenotypes. Canonical pathway analysis showed upregulation of oxidative phosphorylation genes indicative of mitochondrial dysfunction (52% of genes in pathway). The uninflamed phenotype was characterized by upregulation of mitogen-activated protein kinase pathways. Conclusions: A third of genes are differentially expressed between biologic phenotypes of ARDS supporting the observation that the subgroups of ARDS are incomparable in terms of pathophysiology. These data provide additional support for biologic heterogeneity in patients with ARDS and suggests that a personalized approach to intervention focusing on oxidative phosphorylation is pivotal in this condition.

Personalized pharmacological therapy for ARDS: a light at the end of the tunnel

Introduction: Pharmacotherapy for the acute respiratory distress syndrome (ARDS) has been tested in preclinical and clinical studies. However, to date, no pharmacological interventions have proven effective. This may be attributed to lack of proper identification of different ARDS phenotypes.Areas covered: We designed inclusive search strings and searched four bibliographic databases (Cochrane Database of Systematic Reviews, PubMed, Web of Science, and clinicaltrials.gov) to identify relevant research. Search results were mainly restricted to papers published from 2009 through 2019. ARDS is a heterogeneous syndrome, and its different phenotypes - defined according to clinical, radiological, and biological parameters - may affect response to therapy. The most promising pharmacological approaches to date have been based on ARDS pathophysiology. They focus on reducing inflammation and pulmonary edema, promoting selective vasodilation, and repairing alveolar epithelial and endothelial cells.Expert opinion: Pharmacotherapeutic approaches targeting ARDS pathophysiology have failed to exert beneficial effects. Personalized medicine targeting the different ARDS phenotypes has emerged as an option to improve survival. Identification of specific ARDS patient phenotypes that respond to specific therapies seems to be the most important challenge for the next decade. Additional research is warranted before personalized medicine approaches can be applied at bedside for ARDS patients.

Azithromycin does not improve disease severity in acute experimental pancreatitis

Acute pancreatitis is a severe systemic disease triggered by a sterile inflammation and initial local tissue damage of the pancreas. Immune cells infiltrating into the pancreas are main mediators of acute pancreatitis pathogenesis. In addition to their antimicrobial potency, macrolides possess anti-inflammatory and immunomodulatory properties which are routinely used in patients with chronic airway infections and might also beneficial in the treatment of acute lung injury. We here tested the hypothesis that the macrolide antibiotic azithromycin can improve the course of acute experimental pancreatitis via ameliorating the damage imposed by sterile inflammation, and could be used as a disease specific therapy. However, our data show that azithromycin does not have influence on caerulein induced acute pancreatitis in terms of reduction of organ damage, and disease severity. Furthermore Infiltration of immune cells into the pancreas or the lungs was not attenuated by azithromycin as compared to controls or ampicillin treated animals with acute experimental pancreatitis. We conclude that in the chosen model, azithromycin does not have any beneficial effects and that its immunomodulatory properties cannot be used to decrease disease severity in the model of caerulein-induced pancreatitis in mice.