Effects of sevoflurane postconditioning on cell death, inflammation and TLR expression in human endothelial cells exposed to LPS

Abstract

BackgroundSevoflurane is an anesthetic agent which also participates in protective mechanisms in sepsis, likely due to anti-inflammatory properties. A key tissue in sepsis is the endothelium, which expresses TLR2 and TLR4 receptors, known regulators of inflammatory mechanisms and potential therapeutic targets for this pathology. In this context, we explored the effect of sevoflurane postconditioning in an in vitro sepsis model.MethodsPrimary cultures of human umbilical vein endothelial cells were used for two different experiments. In the first set, cultures were placed in an airtight incubation chamber and exposed to different concentrations of sevoflurane (0,1,3 or 7% vol,) for 1 hour. In the second set, lipopolysaccharide from Escherichia coli 0111:B4 (1 μg/mL) was added to culture medium for 3 hours and cells were subsequently exposed to sevoflurane (0,1,3 or 7% vol,) for 1 hour as explained before. In both cases, cell viability was measured by MTT and Trypan blue assays, TLR2 and TLR4 expression were analyzed by flow cytometry, and TNFα and IL-6 levels were quantified in cell culture media by an immunoassay immediately after exposure, at 6 and 24 hours.ResultsExposure to 3% sevoflurane decreased TLR2 at 24 hours and TLR4 at 6 and 24 hours (both p<0.05), whereas exposure to 7% decreased TLR4 expression at 6 hours (p<0.05). Both 3 and 7% sevoflurane decreased TNF-α and IL-6 levels at 24 hours (both p<0.05). In LPS-stimulated cultures, exposure to 3% sevoflurane was cytoprotective at 6 and 24 hours (p<0.05) compared with control, and decreased TLR2 and TLR4 expression at 24 hours (p<0.05); whereas 7% decreased TLR4 expression at 24 hours (p<0.05). Both 3% and 7% sevoflurane decreased TNF-α and IL-6 levels at 24 hours (both p<0.05).ConclusionsPostconditioning with the halogenated anesthetic agent sevoflurane after LPS stimulation shows a cytoprotective effect in an in vitro model, decreasing cell death and reducing TLR2 and TLR4 expression as well as levels of the inflammatory mediators TNF-α and IL-6 in human endothelial cells.

Repeated inhalation of sevoflurane inhibits airway inflammation in an OVA‐induced mouse model of allergic airway inflammation

“…Both clinical and experimental studies have shown that inhalation of SVF has beneficial effects on lung mechanics reducing airway resistance in asthmatic individuals . In addition, previous studies have shown that inhalation of SVF mitigates lipopolysaccharide‐induced epithelial cell and macrophage injury, reduces airway inflammatory infiltrates in rodents and benefits patients with acute lung injury . Given that SVF is a short‐acting drug and usually administrated repeatedly in the clinic, our findings extended previous observation.…”

Reflex control of inflammation by the splanchnic anti-inflammatory pathway is sustained and independent of anesthesia

“…Despite a general acceptance of the conclusions arising from those studies, the possible confounding role of anesthesia has not been systematically addressed. Anesthesia itself has an anti-inflammatory influence (3,10,13,17,23,29,36), which has been suggested to be mediated by sympathetic nerves (3), although other evidence shows that anesthetics can suppress inflammation by non-neural cellular mechanisms (23,36). The first aim of the present study was, therefore, to test whether the splanchnic anti-inflammatory pathway is activated in response to endotoxemia independently of anesthesia.…”

Sevoflurane Abolishes Oxygenation Impairment in a Long-term Rat Model of Acute Lung Injury

“…Another potential mediator for the sevoflurane effect we observed is downregulation of toll-like receptor 2 and toll-like receptor 4 resulting in an attenuation of proinflammatory cytokines. 40 Although not assessed in this current study, phosphorylation of extracellular-regulated kinase in macrophages on LPS stimulation may be another sevoflurane-mediated immunomodulatory mechanism. 41 In contrast to previous studies, we found that pulmonary albumin content, 12,42 another integrity marker of the alveolocapillary barrier, was not different between propofol and sevoflurane groups.…”

“…40,41 In our study, however, we targeted a sevoflurane dose that mimics long-term sedation in the ICU. For that, 0.5 minimal alveolar concentration sevoflurane is sufficient.…”