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Gastric aspiration lung injury is one of the most common clinical events. This study investigated the effects of bone-marrow-derived mesenchymal stem cells (BMSCs) on combined acid plus small non-acidified particle (CASP)-induced aspiration lung injury. Enhanced green fluorescent protein (EGFP(+) ) or EGFP(-) BMSCs or 15d-PGJ2 were injected via the tail vein into rats immediately after CASP-induced aspiration lung injury. Pathological changes in lung tissues, blood gas analysis, the wet/dry weight ratio (W/D) of the lung, levels of total proteins and number of total cells and neutrophils in bronchoalveolar lavage fluid (BALF) were determined. The cytokine levels were measured using ELISA. Protein expression was determined by Western blot. Bone-marrow-derived mesenchymal stem cells treatment significantly reduced alveolar oedema, exudation and lung inflammation; increased the arterial partial pressure of oxygen; and decreased the W/D of the lung, the levels of total proteins and the number of total cells and neutrophils in BALF in the rats with CASP-induced lung injury. Bone-marrow-derived mesenchymal stem cells treatment decreased the levels of tumour necrosis factor-α and Cytokine-induced neutrophil chemoattractant (CINC)-1 and the expression of p-p65 and increased the levels of interleukin-10 and 15d-PGJ2 and the expression of peroxisome proliferator-activated receptor (PPAR)-γ in the lung tissue in CASP-induced rats. Tumour necrosis factor-α stimulated BMSCs to secrete 15d-PGJ2 . A tracking experiment showed that EGFP(+) BMSCs were able to migrate to local lung tissues. Treatment with 15d-PGJ2 also significantly inhibited CASP-induced lung inflammation and the production of pro-inflammatory cytokines. Our results show that BMSCs can protect lung tissues from gastric aspiration injury and inhibit lung inflammation in rats. A beneficial effect might be achieved through BMSC-derived 15d-PGJ2 activation of the PPAR-γ receptor, reducing the production of proinflammatory cytokines., (© 2016 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.)

Background: This study uses statistical predictive modeling and hierarchical cluster analyses to examine inflammatory mediators and cells in bronchoalveolar lavage (BAL) as putative biomarkers in rats with blunt trauma lung contusion (LC), gastric aspiration (combined acid and small gastric food particles, CASP), or a combination of the two., Methods: Specific parameters assessed in the innate pulmonary inflammatory response were leukocytes, macrophages, and polymorphonuclear neutrophils (PMNs) in BAL; whole lung myeloperoxidase activity; and a series of cytokines or chemokines present in BAL at 5 or 24 hours after injury: tumor necrosis factor-alpha, interleukin (IL)-1beta, IL-6, interferon-gamma, IL-10, macrophage inflammatory protein-2, cytokine-induced neutrophil chemoattractant-1, and monocyte chemoattractant protein-1., Results: Rats with LC, CASP, LC + CASP all had severe lung injury compared with uninjured controls based on decreased arterial oxygenation or increased BAL albumin at 5 or 24 hours postinsult. However, the injury groups had distinct overall patterns of inflammation that allowed them to be discriminated accurately by hierarchical cluster analysis (29 of 30 and 35 of 37 rats were correctly classified in hierarchical clusters at 5 and 24 hours, respectively). Moreover, predictive analyses based on an extension of standard receiver-operator characteristic methodology discriminated individual animals and groups with similar high accuracy based on a maximum of two inflammatory parameters per group (29 of 30 and 36 of 37 rats were correctly classified at 5 hours and 24 hours, respectively)., Conclusions: These results support the possibility that inflammatory biomarker profiles could be developed in the future to improve the diagnosis and management of trauma patients with unwitnessed (occult) gastric aspiration who have an increased risk of clinical acute lung injury or the acute respiratory distress syndrome.

Gastric aspiration, which can cause acute, diffuse, inflammatory lung injury, is of particular concern in critically ill patients. This study aimed to determine the effects of immediate prone positioning on the degree of lung injury and inflammatory response induced by gastric aspiration. Following induction of gastric aspiration by injection of gastric fluid, 16 healthy pigs were randomized to one of two groups: supine position (SP) or prone position (PP). After ventilation and monitoring for 6 hr, all pigs were euthanized. The ratio of the partial pressure of arterial oxygen/fraction of inspired oxygen (PaO2/FIO2) and the partial pressure of arterial carbon dioxide (PaCO2) were recorded during the 6-hr study period. Serum levels of interleukin (IL)-6 were measured every 2 hr, and the mean optical density (MOD) of IL-6 in lung tissues and lung-injury scores were measured at the end of the experiment. The PP group showed a significantly higher PaO2/FIO2 ratio, lower serum IL-6 concentration (p =.015), lower lung-injury scores (p =.012), and lower IL-6 concentration and MOD of IL-6 in lung tissue, especially in dorsal (p =.001, p =.021, respectively) and nondependent regions (p =.005, p =.035, respectively) than the SP group. There were no statistically significant differences in PaCO2 between the groups. Lung-injury severity was positively correlated with the IL-6 concentration and MOD of IL-6 in lung tissues (p <.05). These results suggest that immediate prone positioning alleviated the degree of aspiration-induced lung injury, possibly through mitigating IL-6-mediated lung inflammation. [ABSTRACT FROM AUTHOR]

Background: Evidence of aspiration remains a major reason for declining donor lungs contributing to current organ shortage. The aim of the present ex vivo lung perfusion (EVLP) study was to compare lungs injured by gastric juice (GJ) with normal lungs. Methods: Pigs (32.3 ± 11.2 kg) were divided into two groups. Study group [GJ; n = 6] was intratracheally instilled with GJ, while sham bronchoscopy was performed in control group [C; n = 6]. Graft function was assessed during EVLP for 2 h. Oxygenation, aerodynamic, and hemodynamic parameters were recorded every 30 min. Wet to dry weight ratio (W/D) was calculated. Bronchoalveolar lavage was performed. Tissue samples were collected. Results: Pulmonary vascular resistance was higher and pulmonary flow was lower in [GJ] versus [C] at T120; (P < 0.05). Mean airway pressure was higher in (P < 0.05) and compliance was lower (P < 0.001) in [GJ]. No differences in oxygenation were seen between groups. W/D of left lung in [GJ] after EVLP was slightly (P < 0.05) higher compared with the nonperfused right lung. More neutrophils were present in [GJ] before (P < 0.01) and after EVLP (P < 0.05). Histologic alterations were more prominent in [GJ], but did not worsen after EVLP. Conclusion: EVLP of injured lungs is possible for 2 h despite increased edema. This model could help to investigate ways to repair caustic lung injury during EVLP. [Copyright &y& Elsevier]