American journal of respiratory and critical care medicine
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Am. J. Respir. Crit. Care Med. · Aug 2018
Staphylococcus aureus Induces a Mucosal Type 2 Immune Response via Epithelial Cell-derived Cytokines.
Chronic rhinosinusitis with nasal polyps is characterized by a T-helper cell type 2-skewed upper airway inflammation. Mucosal Staphylococcus aureus colonization is found in the majority of patients with nasal polyps. S. aureus is known to induce type 2 cytokine release via enterotoxins. ⋯ This study demonstrates for the first time that S. aureus can directly induce epithelial cell-derived cytokine release via binding to Toll-like receptor 2, and may thereby propagate type 2 cytokine expression in nasal polyp tissue.
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Am. J. Respir. Crit. Care Med. · Aug 2018
The Extracorporeal Life Support Organization Maastricht Treaty for Nomenclature in Extracorporeal Life Support. A Position Paper of the Extracorporeal Life Support Organization.
Extracorporeal life support (ECLS) was developed more than 50 years ago, initially with venoarterial and subsequently with venovenous configurations. As the technique of ECLS significantly improved and newer skills developed, complexity in terminology and advances in cannula design led to some misunderstanding of and inconsistency in definitions, both in clinical practice and in scientific research. ⋯ The goal is to provide a consistent and unambiguous nomenclature for ECLS and to overcome the inconsistent use of abbreviations for ECLS cannulation. Secondary benefits are ease of multicenter collaboration in research, improved registry data quality, and clear communication among practitioners and researchers in the field.
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Am. J. Respir. Crit. Care Med. · Aug 2018
Positive End-Expiratory Pressure Ventilation Induces Longitudinal Atrophy in Diaphragm Fibers.
Diaphragm weakness in critically ill patients prolongs ventilator dependency and duration of hospital stay and increases mortality and healthcare costs. The mechanisms underlying diaphragm weakness include cross-sectional fiber atrophy and contractile protein dysfunction, but whether additional mechanisms are at play is unknown. ⋯ Mechanical ventilation with PEEP results in longitudinal atrophy of diaphragm fibers, a response that is modulated by the elasticity of the giant sarcomeric protein titin. We postulate that longitudinal atrophy, in concert with the aforementioned cross-sectional atrophy, hampers spontaneous breathing trials in critically ill patients: during these efforts, end-expiratory lung volume is reduced, and the shortened diaphragm fibers are stretched to excessive sarcomere lengths. At these lengths, muscle fibers generate less force, and diaphragm weakness ensues.
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Am. J. Respir. Crit. Care Med. · Aug 2018
Dicer1 Deficiency in the Idiopathic Pulmonary Fibrosis Fibroblastic Focus Promotes Fibrosis by Suppressing MicroRNA Biogenesis.
The lung extracellular matrix (ECM) in idiopathic pulmonary fibrosis (IPF) mediates progression of fibrosis by decreasing fibroblast expression of miR-29 (microRNA-29), a master negative regulator of ECM production. The molecular mechanism is undefined. IPF-ECM is stiffer than normal. Stiffness drives fibroblast ECM production in a YAP (yes-associated protein)-dependent manner, and YAP is a known regulator of miR-29. Therefore, we tested the hypothesis that negative regulation of miR-29 by IPF-ECM was mediated by mechanotransduction of stiffness. ⋯ Our data identify suppression of fibroblast Dicer1 expression in the myofibroblast-rich IPF fibroblastic focus core as a central step in the mechanism by which the ECM sustains fibrosis progression in IPF.