Comparison of direct and indirect models of early induced acute lung injury

The animal experimental counterpart of human acute respiratory distress syndrome (ARDS) is acute lung injury (ALI). Most models of ALI involve reproducing the clinical risk factors associated with human ARDS, such as sepsis or acid aspiration; however, none of these models fully replicates human ARDS. To compare different experimental animal models of ALI, based on direct or indirect mechanisms of lung injury, to characterize a model which more closely could reproduce the acute phase of human ARDS. Adult male Sprague-Dawley rats were subjected to intratracheal instillations of (1) HCl to mimic aspiration of gastric contents; (2) lipopolysaccharide (LPS) to mimic bacterial infection; (3) HCl followed by LPS to mimic aspiration of gastric contents with bacterial superinfection; or (4) cecal ligation and puncture (CLP) to induce peritonitis and mimic sepsis. Rats were sacrificed 24 h after instillations or 24 h after CLP. At 24 h, rats instilled with LPS or HCl-LPS had increased lung permeability, alveolar neutrophilic recruitment and inflammatory markers (GRO/KC, TNF-α, MCP-1, IL-1β, IL-6). Rats receiving only HCl or subjected to CLP had no evidence of lung injury. Rat models of ALI induced directly by LPS or HCl-LPS more closely reproduced the acute phase of human ARDS than the CLP model of indirectly induced ALI

INHALEd nebulised unfractionated HEParin for the treatment of hospitalised patients with COVID‐19 (INHALE‐HEP): Protocol and Statistical Analysis Plan for an investigator‐initiated international meta‐trial of randomised studies

Aims: inhaled nebulised unfractionated heparin (UFH) has a strong scientific and biological rationale that warrants urgent investigation of its therapeutic potential in patients with COVID‐19. UFH has antiviral effects and prevents the SARS‐CoV‐2 virus' entry into mammalian cells. In addition, UFH has significant anti‐inflammatory and anticoagulant properties, which limit progression of lung injury and vascular pulmonary thrombosis.Methods: the INHALEd nebulised unfractionated HEParin for the treatment of hospitalised patients with COVID‐19 (INHALE‐HEP) metatrial is a prospective individual patient data analysis of on‐going randomised controlled trials and early phase studies. Individual studies are being conducted in multiple countries. Participating studies randomise adult patients admitted to the hospital with confirmed SARS‐CoV‐2 infection, who do not require immediate mechanical ventilation, to inhaled nebulised UFH or standard care. All studies collect a minimum core dataset. The primary outcome for the metatrial is intubation (or death, for patients who died before intubation) at day 28. The secondary outcomes are oxygenation, clinical worsening and mortality, assessed in time‐to‐event analyses. Individual studies may have additional outcomes.Analysis: we use a Bayesian approach to monitoring, followed by analysing individual patient data, outcomes and adverse events. All analyses will follow the intention‐to‐treat principle, considering all participants in the treatment group to which they were assigned, except for cases lost to follow‐up or withdrawn.Trial registration, ethics and dissemination: the metatrial is registered at ClinicalTrials.gov ID NCT04635241. Each contributing study is individually registered and has received approval of the relevant ethics committee or institutional review board. Results of this study will be shared with the World Health Organisation, published in scientific journals and presented at scientific meetings