Sevoflurane posttreatment prevents oxidative and inflammatory injury in ventilator-induced lung injury.

Mechanical ventilation is a life-saving clinical treatment but it can induce or aggravate lung injury. New therapeutic strategies, aimed at reducing the negative effects of mechanical ventilation such as excessive production of reactive oxygen species, release of pro-inflammatory cytokines, and transmigration as well as activation of neutrophil cells, are needed to improve the clinical outcome of ventilated patients. Though the inhaled anesthetic sevoflurane is known to exert organ-protective effects, little is known about the potential of sevoflurane therapy in ventilator-induced lung injury. This study focused on the effects of delayed sevoflurane application in mechanically ventilated C57BL/6N mice. Lung function, lung injury, oxidative stress, and inflammatory parameters were analyzed and compared between non-ventilated and ventilated groups with or without sevoflurane anesthesia. Mechanical ventilation led to a substantial induction of lung injury, reactive oxygen species production, pro-inflammatory cytokine release, and neutrophil influx. In contrast, sevoflurane posttreatment time dependently reduced histological signs of lung injury. Most interestingly, increased production of reactive oxygen species was clearly inhibited in all sevoflurane posttreatment groups. Likewise, the release of the pro-inflammatory cytokines interleukin-1ß and MIP-1ß and neutrophil transmigration were completely prevented by sevoflurane independent of the onset of sevoflurane administration. In conclusion, sevoflurane posttreatment time dependently limits lung injury, and oxidative and pro-inflammatory responses are clearly prevented by sevoflurane irrespective of the onset of posttreatment. These findings underline the therapeutic potential of sevoflurane treatment in ventilator-induced lung injury.

Hydrogen Sulfide Exerts Anti-oxidative and Anti-inflammatory Effects in Acute Lung Injury.

Acute lung injury (ALI) caused by septic stimuli is still a major problem in critical care patients. We have shown previously that hydrogen sulfide (H2S) mediates anti-inflammatory and lung protective effects. In the present study, we aimed to investigate the underlying mechanisms. C57BL/6N mice were instilled with lipopolysaccharide (LPS) intranasally in the absence or presence of inhaled H2S for 6 h. LPS instillation led to alveolar wall thickening, an elevated ALI score, increased neutrophil transmigration, and elevated interleukin-1ß cytokine release into the bronchoalveolar lavage fluid. In contrast, H2S inhalation prevented lung injury and inflammation despite LPS treatment. Moreover, H2S inhalation significantly inhibited protein expression of cystathionine-ß-synthetase, heat shock protein 70, phosphorylated p38 MAP kinase, NADPH oxidase 2, and the formation of reactive oxygen species (ROS) in LPS-challenged animals. In conclusion, H2S prevents LPS-induced ALI by inhibition of pro-inflammatory and oxidative responses via the concerted attenuation of stress protein, MAP kinase, and ROS signaling pathways.

Corrigendum to "Hydrogen Sulfide Prevents Formation of Reactive Oxygen Species through PI3K/Akt Signaling and Limits Ventilator-Induced Lung Injury".

[This corrects the article DOI: 10.1155/2017/3715037.].

Correction: Pre- and posttreatment with hydrogen sulfide prevents ventilator-induced lung injury by limiting inflammation and oxidation.

[This corrects the article DOI: 10.1371/journal.pone.0176649.].

Pre- and posttreatment with hydrogen sulfide prevents ventilator-induced lung injury by limiting inflammation and oxidation.

Although essential in critical care medicine, mechanical ventilation often results in ventilator-induced lung injury. Low concentrations of hydrogen sulfide have been proven to have anti-inflammatory and anti-oxidative effects in the lung. The aim of this study was to analyze the kinetic effects of pre- and posttreatment with hydrogen sulfide in order to prevent lung injury as well as inflammatory and oxidative stress upon mechanical ventilation. Mice were either non-ventilated or mechanically ventilated with a tidal volume of 12 ml/kg for 6 h. Pretreated mice inhaled hydrogen sulfide in low dose for 1, 3, or 5 h prior to mechanical ventilation. Posttreated mice were ventilated with air followed by ventilation with hydrogen sulfide in various combinations. In addition, mice were ventilated with air for 10 h, or with air for 5 h and subsequently with hydrogen sulfide for 5 h. Histology, interleukin-1ß, neutrophil counts, and reactive oxygen species formation were examined in the lungs. Both pre-and posttreatment with hydrogen sulfide time-dependently reduced or even prevented edema formation, gross histological damage, neutrophil influx and reactive oxygen species production in the lung. These results were also observed in posttreatment, when the experimental time was extended and hydrogen sulfide administration started as late as after 5 h air ventilation. In conclusion, hydrogen sulfide exerts lung protection even when its application is limited to a short or delayed period. The observed lung protection is mediated by inhibition of inflammatory and oxidative signaling.

Hydrogen Sulfide Prevents Formation of Reactive Oxygen Species through PI3K/Akt Signaling and Limits Ventilator-Induced Lung Injury.

The development of ventilator-induced lung injury (VILI) is still a major problem in mechanically ventilated patients. Low dose inhalation of hydrogen sulfide (H2S) during mechanical ventilation has been proven to prevent lung damage by limiting inflammatory responses in rodent models. However, the capacity of H2S to affect oxidative processes in VILI and its underlying molecular signaling pathways remains elusive. In the present study we show that ventilation with moderate tidal volumes of 12 ml/kg for 6 h led to an excessive formation of reactive oxygen species (ROS) in mice lungs which was prevented by supplemental inhalation of 80 parts per million of H2S. In addition, phosphorylation of the signaling protein Akt was induced by H2S. In contrast, inhibition of Akt by LY294002 during ventilation reestablished lung damage, neutrophil influx, and proinflammatory cytokine release despite the presence of H2S. Moreover, the ability of H2S to induce the antioxidant glutathione and to prevent ROS production was reversed in the presence of the Akt inhibitor. Here, we provide the first evidence that H2S-mediated Akt activation is a key step in protection against VILI, suggesting that Akt signaling limits not only inflammatory but also detrimental oxidative processes that promote the development of lung injury.

Inhaled Anesthetics Exert Different Protective Properties in a Mouse Model of Ventilator-Induced Lung Injury.

BACKGROUND: Mechanical ventilation is an important perioperative tool in anesthesia and a lifesaving treatment for respiratory failure, but it can lead to ventilator-associated lung injury. Inhaled anesthetics have demonstrated protective properties in various models of organ damage. We compared the lung-protective potential of inhaled sevoflurane, isoflurane, and desflurane in a mouse model of ventilator-induced lung injury (VILI). METHODS: C57BL/6N mice were randomized into 5 groups (n = 8/group). One group served as a control and 4 groups were subjected to mechanical ventilation with air (12 mL/kg tidal volume) for 6 hours. Ventilated animals were anesthetized with either ketamine and acepromazine, or 1 of 3 inhaled anesthetics: isoflurane, sevoflurane, or desflurane. Lung injury was assessed by lung histology, neutrophil counts, and interleukin-1ß concentrations in bronchoalveolar lavage fluid. Antioxidant effects were explored by evaluation of production of reactive oxygen species (ROS) and glutathione content in lung tissue by immunofluorescence staining and confocal laser scanning microscopy. Changes in intercellular adhesion molecule-1 and src-protein-tyrosine-kinase levels were determined by real-time polymerase chain reaction and Western blot. RESULTS: Compared with nonventilated controls, ventilated mice anesthetized with ketamine had thickened alveolar walls, elevated VILI scores, higher polymorph neutrophil counts, and increased ROS production. Mice anesthetized with isoflurane and sevoflurane showed thinner alveolar septa, lower VILI scores, lower polymorph neutrophil counts, and lower interleukin-1ß concentrations than ketamine mice. The expression of intercellular adhesion molecule-1/src-protein-tyrosine-kinase was neither affected by mechanical ventilation nor affected by administration of inhaled anesthetics. Mice anesthetized with isoflurane and sevoflurane showed less ROS production and higher glutathione contents compared with ketamine mice. Unexpectedly, desflurane-ventilated mice showed similar signs of lung injury compared with mice ventilated with air alone and receiving ketamine anesthesia. Desflurane failed to inhibit inflammatory responses and ROS production in lung tissue and developed no antioxidant potential. CONCLUSIONS: Although isoflurane and sevoflurane prevent ventilator-associated lung injury, desflurane does not. As an underlying mechanism, both inhaled anesthetics exert major anti-inflammatory and antioxidative effects.

Isoflurane but not sevoflurane or desflurane aggravates injury to neurons in vitro and in vivo via p75NTR-NF-ĸB activation.

BACKGROUND: General anesthesia in patients with or at risk for neuronal injury remains challenging due to the controversial influence of volatile anesthetics on neuronal damage. We hypothesized that isoflurane, sevoflurane, and desflurane would exert variable degrees of neurotoxicity in vitro and in vivo via activation of the p75 neurotrophin receptor (p75). METHODS: SH-SY5Y cells were exposed to oxygen-glucose deprivation (OGD, 16 hours), preceded or followed by incubation with isoflurane, sevoflurane, or desflurane (1.2 minimal alveolar concentration, 2 hours). Neuronal cell death was analyzed by flow cytometry (mitochondrial membrane potential, Annexin V/propidium iodide [AV/Pi]) and quantification of lactate dehydrogenase release. We analyzed NF-κB activity by DNA-binding ELISA and luciferase assay. The role of p75 was studied using the p75-blocking peptide TAT-pep5 and siRNA knockdown. The effect of isoflurane ±p75 inhibition on retinal ischemia-reperfusion injury (IRI) in adult Sprague-Dawley rats was assessed by analyzing retinal ganglion cell (RGC) density. RESULTS: Isoflurane but not sevoflurane or desflurane postexposure aggravated OGD-induced neuronal cell death (AV/Pi positive cells: OGD 41.1% [39.0/43.3] versus OGD + isoflurane 48.5% [46.4/63.4], P = 0.001). Isoflurane significantly increased NF-κB DNA-binding and transcriptional activity of NF-κB (relative Luminescence Units: OGD 500 [499/637] versus OGD + isoflurane 1478 [1363/1643], P = 0.001). Pharmacological inhibition or siRNA knockdown of p75 counteracted the aggravating effects of isoflurane. Isoflurane increased RGC damage in vivo (IRI 1479 RGC/mm(2) [1311/1697] versus IRI + isoflurane 1170 [1093/1211], P = 0.03), which was counteracted by p75-inhibition via TAT-pep5 (P = 0.02). CONCLUSIONS: Isoflurane but not sevoflurane or desflurane postexposure aggravates neurotoxicity in preinjured neurons via activation of p75 and NF-κB. These findings may have implications for the choice of volatile anesthetic being used in patients with or at risk for neuronal injury, specifically in patients with a stroke or history of stroke and in surgical procedures in which neuronal injury is likely to occur, such as cardiac surgery and neurovascular interventions.

Mucin-1 and its relation to grade, stage and survival in ovarian carcinoma patients.

BACKGROUND: Mucin-1 is known to be over-expressed by various human carcinomas and is shed into the circulation where it can be detected in patient's serum by specific anti-Mucin-1 antibodies, such as the tumour marker assays CA 15-3 and CA 27.29. The prognostic value of Mucin-1 expression in ovarian carcinoma remains uncertain. One aim of this study was to compare the concentrations of Mucin-1 in a cohort of patients with either benign or malignant ovarian tumours detected by CA 15-3 and CA 27.29. Another aim of this study was to evaluate Mucin-1 expression by immunohistochemistry in a different cohort of ovarian carcinoma patients with respect to grade, stage and survival. METHODS: Patients diagnosed with and treated for ovarian tumours were included in the study. Patient characteristics, histology including histological subtype, tumour stage, grading and follow-up data were available from patient records. Serum Mucin-1 concentrations were measured with ELISA technology detecting CA 15-3 and CA 27.29, Mucin-1 tissue expression was determined by immunohistochemistry using the VU4H5 and VU3C6 anti-Mucin-1 antibodies. Statistical analysis was performed by using SPSS 18.0. RESULTS: Serum samples of 118 patients with ovarian tumours were obtained to determine levels of Mucin-1. Median CA 15-3 and CA 27.29 concentrations were significantly higher in patients with malignant disease (p< 0.001) than in patients with benign disease.Paraffin-embedded tissue of 154 patients with ovarian carcinoma was available to determine Mucin-1 expression. The majority of patients presented with advanced stage disease at primary diagnosis. Median follow-up time was 11.39 years. Immunohistochemistry results for VU4H5 showed significant differences with respect to tumour grade, FIGO stage and overall survival. Patients with negative expression had a mean overall survival of 9.33 years compared to 6.27 years for patients with positive Mucin-1 expression. CONCLUSIONS: This study found significantly elevated Mucin-1 serum concentrations in ovarian carcinoma patients as compared to those women suffering from benign ovarian diseases. However, it needs to be noted that Mucin-1 concentrations in carcinoma patients showed a rather high variability. Results from immunohistochemistry indicate that Mucin-1 has a prognostic relevance in ovarian carcinomas when evaluating the expression by VU4H5 antibody.

Inhaled hydrogen sulfide protects against lipopolysaccharide-induced acute lung injury in mice.

BACKGROUND: Local pulmonary and systemic infections can lead to acute lung injury (ALI). The resulting lung damage can evoke lung failure and multiple organ dysfunction associated with increased mortality. Hydrogen sulfide (H2S) appears to represent a new therapeutic approach to ALI. The gas has been shown to mediate potent anti-inflammatory and organ protective effects in vivo. This study was designed to define its potentially protective role in sepsis-induced lung injury. METHODS: C57BL/6 N mice received lipopolysaccharide (LPS) intranasally in the absence or presence of 80 parts per million H2S. After 6 h, acute lung injury was determined by comparative histology. Bronchoalveolar lavage (BAL) fluid was analyzed for total protein content and differential cell counting. BAL and serum were further analyzed for interleukin-1ß, macrophage inflammatory protein-2, and/or myeloperoxidase glycoprotein levels by enzyme-linked immunosorbent assays. Differences between groups were analyzed by one way analysis of variance. RESULTS: Histological analysis revealed that LPS instillation led to increased alveolar wall thickening, cellular infiltration, and to an elevated ALI score. In the presence of H2S these changes were not observed despite LPS treatment. Moreover, neutrophil influx, and pro-inflammatory cytokine release were enhanced in BAL fluid of LPS-treated mice, but comparable to control levels in H2S treated mice. In addition, myeloperoxidase levels were increased in serum after LPS challenge and this was prevented by H2S inhalation. CONCLUSION: Inhalation of hydrogen sulfide protects against LPS-induced acute lung injury by attenuating pro-inflammatory responses.