Sepsis Enhances Epithelial Permeability with Stretch in an Actin Dependent Manner

Ventilation of septic patients often leads to the development of edema and impaired gas exchange. We hypothesized that septic alveolar epithelial monolayers would experience stretch-induced barrier dysfunction at a lower magnitude of stretch than healthy alveolar epithelial monolayers. Alveolar epithelial cells were isolated from rats 24 hours after cecal ligation and double puncture (2CLP) or sham surgery. Following a 5-day culture period, monolayers were cyclically stretched for 0, 10, or 60 minutes to a magnitude of 12% or 25% change in surface area (ΔSA). Barrier function, MAPk and myosin light chain (MLC) phosphorylation, tight junction (TJ) protein expression and actin cytoskeletal organization were examined after stretch. Significant increases in epithelial permeability were observed only in 2CLP monolayers at the 12% ΔSA stretch level, and in both 2CLP and sham monolayers at the 25% ΔSA stretch level. Increased permeability in 2CLP monolayers was not associated with MAPk signaling or alterations in expression of TJ proteins. 2CLP monolayers had fewer actin stress fibers before stretch, a more robust stretch-induced actin redistribution, and reduced phosphorylated MLCK than sham monolayers. Jasplakinolide stabilization of the actin cytoskeleton in 2CLP monolayers prevented significant increases in permeability following 60 minutes of stretch to 12% ΔSA. We concluded that septic alveolar epithelial monolayers are more susceptible to stretch-induced barrier dysfunction than healthy monolayers due to actin reorganization

Traditional and new composite endpoints in heart failure clinical trials: facilitating comprehensive efficacy assessments and improving trial efficiency

Composite endpoints are commonly used as the primary measure of efficacy in heart failure clinical trials to assess the overall treatment effect and to increase the efficiency of trials. Clinical trials still must enrol large numbers of patients to accrue a sufficient number of outcome events and have adequate power to draw conclusions about the efficacy and safety of new treatments for heart failure. Additionally, the societal and health system perspectives on heart failure have raised interest in ascertaining the effects of therapy on outcomes such as repeat hospitalization and the patient's burden of disease. Thus, novel methods for using composite endpoints in clinical trials (e.g. clinical status composite endpoints, recurrent event analyses) are being applied in current and planned trials. Endpoints that measure functional status or reflect the patient experience are important but used cautiously because heart failure treatments may improve function yet have adverse effects on mortality. This paper discusses the use of traditional and new composite endpoints, identifies qualities of robust composites, and outlines opportunities for future research

Recipient clinical risk factors predominate in possible transfusion-related acute lung injury

Background: Possible transfusion-related acute lung injury (pTRALI) cases by definition have a clear temporal relationship to an alternative recipient risk factor for acute respiratory distress syndrome (ARDS). We questioned whether transfusion factors are important for the development of pTRALI. Study Design and Methods: In this nested case-control study, we prospectively identified 145 consecutive patients with pTRALI and randomly selected 163 transfused controls over a 4-year period at the University of California at San Francisco and the Mayo Clinic (Rochester, Minnesota). Results: For pTRALI, we found evidence against transfusion being important: receipt of plasma from female donors (odds ratio [OR], 0.82; 95% confidence interval [CI], 0.29-2.3; p = 0.70), total number of units transfused (OR, 0.99; 95% CI, 0.89-1.10; p = 0.86), and number of red blood cell and whole blood units transfused (OR, 0.78; 95% CI, 0.59-1.03; p = 0.079). In contrast, we found that risk for pTRALI was associated with additional recipient factors: chronic alcohol abuse (OR, 12.5; 95% CI, 2.8-55; p < 0.001), current smoker (OR, 4.2; 95% CI, 1.67-10.8; p = 0.0024), shock before transfusion (OR, 4.6; 95% CI, 2.0-10.7; p < 0.001), and positive fluid balance before transfusion (OR, 1.32/L; 95% CI, 1.20-1.44; p < 0.001). Conclusion: Recipient risk factors for ARDS rather than transfusion risk factors predominate in pTRALI