ObjectiveTwitch transdiaphragmatic pressure is used to evaluate the diaphragm function of mechanical ventilated chronic obstructive pulmonary disease patients before weaning in the intensive care unit, and compared with healthy normal values.MethodsPatients were recruited if they were with acute exacerbation of chronic obstructive pulmonary disease, admitted between May to November in 2013 and December 2014 to February 2016 to the intensive care unit in the First Affiliated Hospital of Guangzhou Medical University, intubated and mechanical ventilated more than 72 hours, and recovered to the clinical stability states after passing the readiness to wean, getting ready for spontaneous breathing test. The newly designed esophageal electrode catheter and bilateral anterolateral magnetic phrenic nerves stimulation were utilized to detect the twitch transdiaphragmatic pressure. At the same time, the function of diaphragm was detected in 10 healthy adults for comparison.ResultsTwenty-two patients were recruited in this study. Two cases had no twitch signals. In the rest 20 cases, the twitch transdiaphragmatic pressure was (7.6±2.5) cm H2O. In 10 healthy adults, twitch transdiaphragmatic pressure was (26.7±4.9) cm H2O. There was significant difference between the patients and the health control subjects (P<0.05).ConclusionTwitch transdiaphragmatic pressure is significantly decreased in weaning chronic obstructive pulmonary disease patients compared with healthy adults.
Objective To study the effect of mechanical stretch on the microenvironment of BEAS-2B on macrophage polarization and the role of polarized macrophages in the epithelial-mesenchymal transition (EMT) of BEAS-2B. Methods Using enzyme linked immunosorbent assay to detect the changes in the levels of cytokines such as interferon-γ, granulocyte-macrophage colony stimulating factor, tumor necrosis factor-α, interleukin (IL)-4, IL-6, IL-10 in the supernatant of lung epithelial cells cultured statically and mechanically stretched. The M0 macrophages (derived from THP-1) were stimulated by stretch/static conditioned medium of BEAS-2B. The surface markers of M1 (CD197) /M2 (CD206) macrophages were detected by flow cytometer. Stretch/static conditioned medium were used to stimulate the co-culture system of macrophages and BEAS-2B in the presence or absence of platelet-derived growth factor receptor inhibitor (PDGFRi), then the protein expression level of EMT makers was examined by Western blot. Results Exposure of BEAS-2B to mechanical stretch resulted in significantly higher production of the pro-M1/M2 polarized factor. The EMT of the co-culture system of M0 and BEAS-2B could be induced by stretch conditioned medium, epithelial marker cytokeratin (CK)-8 and E-cadherin were decreased, while mesenchymal marker α-smooth muscle actin, N-cadherin and vimentin were increased in stretch conditioned medium group. The expression of platelet-derived growth factor (PDGF) was significantly higher in stretch conditioned medium group. The PDGFRi can block the EMT in stretch conditioned medium group. Conclusions The lung epithelial cell supernatant induced by mechanical stretch can promote the polarization of macrophages to M1 and M2. Polarized macrophages promote EMT in human lung epithelial cells via PDGF, and blocking PDGF might attenuate the VILI-associated lung fibrosis.