Volatile anesthetic preconditioning attenuated sepsis induced lung inflammation

Sevoflurane alleviates inflammation, apoptosis and permeability damage of human umbilical vein endothelial cells induced by lipopolysaccharide by inhibiting endoplasmic reticulum stress via upregulating RORα

Endothelial dysfunction often accompanies sepsis. Sevoflurane (Sev) is a widely used inhaled anesthetic that has a protective effect on sepsis-associated damage. We aimed to elucidate the role of Sev in endothelial dysfunction by using a model of LPS induced HUVECs. Sev increased the viability and decreased the apoptosis of HUVECs exposed to LPS. Inflammation and endothelial cell adhesion were improved after Sev addition. Besides, Sev alleviated LPS-induced endothelial cell permeability damage in HUVECs. RORα served as a potential protein that bound to Sev. Importantly, Sev upregulated RORα expression and inhibited endoplasmic reticulum (ER) stress in LPS-treated HUVECs. RORα silencing reversed the impacts of Sev on ER stress. Moreover, RORα deficiency or tunicamycin (ER stress inducer) treatment restored the effects of Sev on the viability, apoptosis, inflammation and endothelial permeability damage of HUVECs exposed to LPS. Taken together, Sev ameliorated LPS-induced endothelial cell damage by targeting RORα to inhibit ER stress.

Effect of General Anesthesia Maintenance with Propofol or Sevoflurane on Fractional Exhaled Nitric Oxide and Eosinophil Blood Count: A Prospective, Single Blind, Randomized, Clinical Study on Patients Undergoing Thyroidectomy

Background: Nitric oxide (NO) is considered a means of detecting airway hyperresponsiveness, since even non-asthmatic patients experiencing bronchospasm intraoperatively or postoperatively display higher levels of exhaled NO. It can also be used as a non-invasive biomarker of lung inflammation and injury. This prospective, single-blind, randomized study aimed to evaluate the impact of two different anesthesia maintenance techniques on fractional exhaled nitric oxide (FeΝO) in patients without respiratory disease undergoing total thyroidectomy under general anesthesia. Methods: Sixty patients without respiratory disease, atopy or known allergies undergoing total thyroidectomy were randomly allocated to receive either inhalational anesthesia maintenance with sevoflurane at a concentration that maintained Bispectral Index (BIS) values between 40 and 50 intraoperatively or intravenous anesthesia maintenance with propofol 1% targeting the same BIS values. FeΝO was measured immediately preoperatively (baseline), postoperatively in the Postanesthesia Care Unit and at 24 h post-extubation with a portable device. Other variables measured were eosinophil blood count preoperatively and postoperatively and respiratory parameters intraoperatively. Results: Patients in both groups presented lower than baseline values of FeΝO measurements postoperatively, which returned to baseline measurements at 24 h post-extubation. In the peripheral blood, a decrease in the percentage of eosinophils was demonstrated, which was significant only in the propofol group. Respiratory lung mechanics were better maintained in the propofol group as compared to the sevoflurane group. None of the patients suffered intraoperative bronchospasm. Conclusions: Both propofol and sevoflurane lead to the temporary inhibition of NO exhalation. They also seem to attenuate systemic hypersensitivity response by reducing the eosinophil count in the peripheral blood, with propofol displaying a more pronounced effect and ensuring a more favorable mechanical ventilation profile as compared to sevoflurane. The attenuation of NO exhalation by both agents may be one of the underlying mechanisms in the reduction in airway hyperreactivity. The clinical significance of this fluctuation remains to be studied in patients with respiratory disease.

Intraoperative administration of isoflurane improves survival in rats exposed to caecal ligation and puncture

Background

Emerging data suggest that volatile anaesthetic agents may be protective during critical illness.

Methods

Three-month-old Sprague Dawley rats were randomly allocated to one of four groups: isoflurane during surgery followed by 3 days of isoflurane 0.8% (and intralipid i.v.), propofol during surgery and 314 μg kg-1 h-1 propofol for 3 days, isoflurane during surgery and intralipid for 3 days, and propofol during surgery and intralipid for 3 days. After induction with propofol or isoflurane, rats breathed oxygen 100% spontaneously via a nose cone. Propofol or intralipid was administered through a 22-gauge jugular vein i.v. catheter. Caecal ligation and puncture was performed through a paramedian incision. The surgical concentration of isoflurane was kept at 2%, and propofol was maintained at 800 μg kg-1 h-1. After recovery and 3 days of exposure to intralipid or anaesthetic agents, the rats were allowed to roam free in an adequately vented, temperature- and humidity-controlled cage with food and water ad libitum.

Results

Rats that received isoflurane for 3 days survived longer than the postoperative propofol group (P=0.0002, log-rank test). Among rats receiving no postoperative anaesthetic, those receiving isoflurane during surgery survived longer than those that received propofol during surgery group (P=0.0081).

Conclusions

Exposure to isoflurane, as opposed to propofol, may improve survival in rats exposed to caecal ligation and puncture.

Isoflurane attenuates sepsis-associated lung injury

Acute lung injury is one of major complications associated with sepsis, responsible for morbidity and mortality. Patients who suffer from acute lung injury often require respiratory support under sedations, and it would be important to know the role of sedatives in lung injury. We examined volatile anesthetic isoflurane, which is commonly used in surgical setting, but also used as an alternative sedative in intensive care settings in European countries and Canada. We found that isoflurane exposure attenuated neutrophil recruitment to the lungs in mice suffering from experimental polymicrobial abdominal sepsis. We found that isoflurane attenuated one of major neutrophil chemoattractants LTB4 mediated response via its receptor BLT1 in neutrophils. Furthermore, we have shown that isoflurane directly bound to BLT1 by a competition assay using newly developed labeled BLT1 antagonist, suggesting that isoflurane would be a BLT1 antagonist.

Propofol Upregulates MicroRNA-30b to Inhibit Excessive Autophagy and Apoptosis and Attenuates Ischemia/Reperfusion Injury In Vitro and in Patients

Evidence reveals that propofol protects cells via suppressing excessive autophagy induced by hypoxia/reoxygenation (H/R). Previously, we found in a genome-wide microRNA profile analysis that several autophagy-related microRNAs were significantly altered during the process of H/R in the presence or absence of propofol posthypoxia treatment (P-PostH), but how these microRNAs work in P-PostH is still largely unknown. Here, we found that one of these microRNAs, microRNA-30b (miR-30b), in human umbilical vein endothelial cells (HUVECs) was downregulated by H/R treatment but significantly upregulated by 100 M propofol after H/R treatment. miR-30b showed similar changes in open heart surgery patients. By dual-luciferase assay, we found that Beclin-1 is the direct target of miR-30b. This conclusion was also supported by knockdown or overexpression of miR-30b. Further studies showed that miR-30b inhibited H/R-induced autophagy activation. Overexpression or knockdown of miR-30b regulated autophagy-related protein gene expression in vitro. To clarify the specific role of propofol in the inhibition of autophagy and distinguish the induction of autophagy from the damage of autophagy flux, we used bafilomycin A1. LC3-II levels were decreased in the group treated with propofol combined with bafilomycin A1 compared with the group treated with bafilomycin A1 alone after hypoxia and reoxygenation. Moreover, HUVECs transfected with Ad-mCherry-GFP-LC3b confirmed the inhibitory effect of miR-30b on autophagy flux. Finally, we found that miR-30b is able to increase the cellular viability under the H/R condition, partially mimicking the protective effect of propofol which suppressed autophagy via enhancing miR-30b and targeting Beclin-1. Therefore, we concluded that propofol upregulates miR-30b to repress excessive autophagy via targeting Beclin-1 under H/R condition. Thus, our results revealed a novel mechanism of the protective role of propofol during anesthesia. Clinical Trial Registration Number. This trial is registered with ChiCTR-IPR-14005470. The name of the trial register: Propofol Upregulates MicroRNA-30b to Repress Beclin-1 and Inhibits Excessive Autophagy and Apoptosis.

Magnetic resonance imaging under isoflurane anesthesia alters cortical cyclooxygenase-2 expression and glial cell morphology during sepsis-associated neurological dysfunction in rats

Background

Magnetic resonance imaging (MRI) of rodents combined with histology allows to determine what mechanisms underlie functional and structural brain changes during sepsis-associated encephalopathy. However, the effects of MRI performed in isoflurane-anesthetized rodents on modifications of the blood-brain barrier and the production of vasoactive prostaglandins and glia cells, which have been proposed to mediate sepsis-associated brain dysfunction, are unknown.

Methods

This study addressed the effect of MRI under isoflurane anesthesia on blood-brain barrier integrity, cyclooxygenase-2 expression, and glial cell activation during cecal ligature and puncture-induced sepsis-associated brain dysfunction in rats.

Results

Cecal ligature and puncture reduced food intake and the righting reflex. MRI under isoflurane anesthesia reduced blood-brain barrier breakdown, decreased circularity of white matter astrocytes, and increased neuronal cyclooxygenase-2 immunoreactivity in the cortex 24 hours after laparotomy. In addition, it annihilated cecal ligature and puncture-induced increased circularity of white matter microglia. MRI under isoflurane anesthesia, however, did not alter sepsis-associated perivascular cyclooxygenase-2 induction.

Conclusion

These findings indicate that MRI under isoflurane anesthesia of rodents can modify neurovascular and glial responses and should, therefore, be interpreted with caution.

Sevoflurane Preconditioning Prevents Septic Myocardial Dysfunction in Lipopolysaccharide-Challenged Mice

Myocardial dysfunction accompanied by severe sepsis could significantly increase the mortality rate of septic patients. This study investigated the effects and the potential mechanisms of sevoflurane preconditioning on septic myocardial dysfunction, which was induced by lipopolysaccharide (LPS; from Escherichia coli O55:B5; 18 mg/kg) in mice. Results indicated that 1 hour after the administration, LPS induced a significant increase in cell-surface Toll-like receptor 4 (TLR4), cytoplasmic IKKα protein expression, and nuclear translocation of nuclear factor kappa-B (NF-κB) protein (P < 0.05), which was attenuated by preconditioning with sevoflurane. Two hours after the administration, inhalation of sevoflurane significantly reduced the serum levels of tumor necrosis factor-alpha (TNF-α), interleukin (IL)-1β, and IL-10 (P < 0.05). Twelve hours after administration, LPS caused pathological damage to the heart and elevated the serum levels of lactate dehydrogenase (LDH) and creatine kinase-MB (P < 0.05). Echocardiography indicated that sevoflurane preconditioning significantly improved systolic and diastolic function. The inhalation of sevoflurane inhibited increases in myeloperoxidase (MPO), macrophage inflammatory protein-2 (MIP-2), TNF-α, and IL-1β levels (P < 0.05) induced by endotoxemia, whereas IL-6 release was facilitated. Sevoflurane attenuated the myocardial levels of nitric oxide (P < 0.05) without an apparent influence on malondialdehyde (MDA) or superoxide dismutase (P > 0.05). In conclusion, our study indicates that exposure to 2% sevoflurane before LPS challenge is protective against myocardial dysfunction. Sevoflurane preconditioning may attenuate neutrophil infiltration and the release of inflammatory mediators during endotoxemia.

Predictors of urinary tract infection in acute stroke patients: A cohort study

Patients with stroke have a high risk of infection which may be predicted by age, procalcitonin, interleukin-6, C-reactive protein, National Institute of Health stroke scale (NHSS) score, diabetes, etc. These prediction methods can reduce unfavourable outcome by preventing the occurrence of infection.We aim to identify early predictors for urinary tract infection in patients after stroke.In 186 collected acute stroke patients, we divided them into urinary tract infection group, other infection type groups, and non-infected group. Data were recorded at admission. Independent risk factors and infection prediction model were determined using Logistic regression analyses. Likelihood ratio test was used to detect the prediction effect of the model. Receiver operating characteristic curve and the corresponding area under the curve were used to measure the predictive accuracy of indicators for urinary tract infection.Of the 186 subjects, there were 35 cases of urinary tract infection. Elevated interleukin-6, higher NIHSS, and decreased hemoglobin may be used to predict urinary tract infection. And the predictive model for urinary tract infection (including sex, NIHSS, interleukin-6, and hemoglobin) have the best predictive effect.This study is the first to discover that decreased hemoglobin at admission may predict urinary tract infection. The prediction model shows the best accuracy.

Nonexperimental Xenobiotics: Unintended Consequences of Intentionally Administered Substances in Terrestrial Animal Models

Review of the use of nonexperimental xenobiotics in terrestrial animal models and the potential unintended consequences of these compounds, including drug-related side effects and adverse reactions.

Silencing of long non-coding RNA MALAT1 suppresses inflammation in septic mice: role of microRNA-23a in the down-regulation of MCEMP1 expression

OBJECTIVE

Sepsis is a life-threatening disease without ideal biomarkers. Some long non-coding RNAs (lncRNAs) are found to be implicated in sepsis. Thus, we investigated the effects of lncRNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) on inflammation in septic mice and the potential mechanisms of the MALAT1/microRNA-23a (miR-23a)/MCEMP1 axis.

METHODS

The sepsis mice model was generated by cecal ligation and puncture (CLP). Then the expressions of lncRNA MALAT1, mast cell-expressed membrane protein 1 (MCEMP1), and miR-23a in septic mice were determined. The interaction between lncRNA MALAT1, miR-23a and MCEMP1 was confirmed. Loss- and gain-of-function approaches were used to verify the roles of the lncRNA MALAT1, miR-23a, and MCEMP1 in inflammation, cell proliferation and apoptosis in septic mice.

RESULTS AND CONCLUSION

The myeloperoxidase (MPO) activity and the expression of interleukin 6 (IL-6), IL-1β, IL-10, and tumor necrosis factor-α (TNF-α) were detected. High expression of the lncRNA MALAT1 and MCEMP1, as well as low expression of miR-23a, was observed in septic mice. LncRNA MALAT1 competitively bound to miR-23a, and miR-23a targeted MCEMP1. Moreover, the down-regulation of lncRNA MALAT1 repressed the expression of MPO, IL-6, IL-10, TNF-α, and IL-1β. Silencing of lncRNA MALAT1 or overexpression of miR-23a reduced inflammation, inhibited cell proliferation, and promoted cell apoptosis in septic mice. Taken together, MALAT1 promotes the inflammation in septic mice by binding to miR-23a to up-regulate MCEMP1. Therefore, silencing of lncRNA MALAT1 might provide a novel therapeutic target for sepsis.

Volatile anesthetics isoflurane and sevoflurane directly target and attenuate Toll-like receptor 4 system

General anesthesia has been the requisite component of surgical procedures for over 150 yr. Although immunomodulatory effects of volatile anesthetics have been growingly appreciated, the molecular mechanism has not been understood. In septic mice, the commonly used volatile anesthetic isoflurane attenuated the production of 5-lipoxygenase products and IL-10 and reduced CD11b and intercellular adhesion molecule-1 expression on neutrophils, suggesting the attenuation of TLR4 signaling. We confirmed the attenuation of TLR4 signaling in vitro and their direct binding to TLR4-myeloid differentiation-2 (MD-2) complex by photolabeling experiments. The binding sites of volatile anesthetics isoflurane and sevoflurane were located near critical residues for TLR4-MD-2 complex formation and TLR4-MD-2-LPS dimerization. Additionally, TLR4 activation was not attenuated by intravenous anesthetics, except for a high concentration of propofol. Considering the important role of TLR4 system in the perioperative settings, these findings suggest the possibility that anesthetic choice may modulate the outcome in patients or surgical cases in which TLR4 activation is expected.-Okuno, T., Koutsogiannaki, S., Hou, L., Bu, W., Ohto, U., Eckenhoff, R. G., Yokomizo, T., Yuki, K. Volatile anesthetics isoflurane and sevoflurane directly target and attenuate Toll-like receptor 4 system.

Pharmacological preconditioning with the cellular stress inducer thapsigargin protects against experimental sepsis

Previous studies have shown that pretreatment with thapsigargin (TG), a cellular stress inducer, produced potent protective actions against various pathologic injuries. So far there is no information on the effects of TG on the development of bacterial sepsis. Using lipopolysaccharides- and cecal ligation/puncture-induced sepsis models in mice, we demonstrated that preconditioning with a single bolus administration of TG conferred significant improvements in survival. The beneficial effects of TG were not mediated by ER stress induction or changes in Toll-like receptor 4 signaling. In vivo and in cultured macrophages, we identified that TG reduced the protein production of pro-inflammatory cytokines, but exhibited no significant effects on steady state levels of their transcriptions. Direct measurement on the fraction of polysome-bound mRNAs revealed that TG reduced the translational efficiency of pro-inflammatory cytokines in macrophages. Moreover, we provided evidence suggesting that repression of the mTOR (the mammalian target of rapamycin) signaling pathway, but not activation of the PERK (protein kinase R-like endoplasmic reticulum kinase)-eIF2α (eukaryotic initiation factor 2α) pathway, might be involved in mediating the TG effects on cytokine production. In summary, our results support that pharmacological preconditioning with TG may represent a novel strategy to prevent sepsis-induced mortality and organ injuries.

Expression of microRNA-23b in patients with sepsis and its effect on leukocytes and the expression of E-selectin and ICAM-1

The expression of microRNA-23b in peripheral blood leukocytes of patients with sepsis was investigated to assess the correlations with leukocyte, E-selectin, ICAM-1 and disease severity. The expression of microRNA-23b in peripheral blood leukocytes from 87 patients with sepsis, 50 patients with systemic inflammatory response syndrome (SIRS) and 50 normal controls were measured by reverse transcription-quantitative PCR (RT-qPCR), and stability of microRNA-23b was evaluated. Enzyme-linked immunosorbent assay (ELISA) was used to detect E-selectin and ICAM-1. Sequential organ failure assessment (SOFA) scoring system was used to assess the severity of sepsis patients. Correlation analysis was performed between microRNA-23b and the total number of white blood cells (WBC), E-selectin, ICAM-1, and SOFA scores. Compared with the normal control group, the expression level of microRNA-23b in the sepsis group was significantly decreased (P<0.05), and WBC and E-selectin were significantly increased (P<0.05). ICAM-1 level in the sepsis and the SIRS groups was significantly higher than that in the control group (P<0.05), and it is also higher in the sepsis group than in the SIRS group. In the sepsis group, the expression level of microRNA-23b in the death group was significantly lower than that in the survivor group (P<0.05), while the level of E-selectin, ICAM-1, and SOFA scores were significantly higher in the death group than in the survivor group (P<0.05), while there was no significant difference in WBC between the groups (P>0.05). The expression level of microRNA-23b in patients with sepsis was significantly negatively correlated with SOFA scores, E-selectin, and ICAM-1 (r=-0.633, -0.585, and -0.439, respectively, P<0.05). The expression of microRNA-23b in peripheral blood of patients with sepsis is related to the manifestation of the inflammatory state, and can be used to judge the severity and prognosis of patients with this disease.

Comparison of oxidative stress under different propofol administration protocols in Thoroughbred racehorses by bOS and bAP assessment

It is desirable to reduce surgery-induced oxidative stress (OS) because it can cause immune suppression and delayed wound healing. Propofol is known to have antioxidant potential and to reduce OS in humans, but there have been no studies of this issue in horses. This study was conducted to evaluate OS under three different propofol administration protocols in Thoroughbred racehorses undergoing arthroscopic surgery with sevoflurane anesthesia. Blood oxidative stress (bOS) and blood antioxidant power (bAP) were used as OS biomarkers. Both bOS and bAP significantly decreased after surgery in all groups, but no differences in these reductions were found among them. Different propofol administration protocols with sevoflurane anesthesia did not cause a difference in OS in Thoroughbred racehorses that underwent arthroscopic surgery.

Sub-anesthesia Dose of Isoflurane in 60% Oxygen Reduces Inflammatory Responses in Experimental Sepsis Models

BACKGROUND

Sepsis is a major cause of mortality in Intensive Care Units. Anesthetic dose isoflurane and 100% oxygen were proved to be beneficial in sepsis; however, their application in septic patients is limited because long-term hyperoxia may induce oxygen toxicity and anesthetic dose isoflurane has potential adverse consequences. This study was scheduled to find the optimal combination of isoflurane and oxygen in protecting experimental sepsis and its mechanisms.

METHODS

The effects of combined therapy with isoflurane and oxygen on lung injury and sepsis were determined in animal models of sepsis induced by cecal ligation and puncture (CLP) or intraperitoneal injection of lipopolysaccharide (LPS) or zymosan. Mouse RAW264.7 cells or human peripheral blood mononuclear cells (PBMCs) were treated by LPS to probe mechanisms. The nuclear factor kappa B (NF-κB) signaling molecules were examined by Western blot and cellular immunohistochemistry.

RESULTS

The 0.5 minimum alveolar concentration (MAC) isoflurane in 60% oxygen was the best combination of oxygen and isoflurane for reducing mortality in experimental sepsis induced by CLP, intraperitoneal injection of LPS, or zymosan. The 0.5 MAC isoflurane in 60% oxygen inhibited proinflammatory cytokines in peritoneal lavage fluids (tumor necrosis factor-alpha [TNF-β]: 149.3 vs. 229.7 pg/ml, interleukin [IL]-1β: 12.5 vs. 20.6 pg/ml, IL-6: 86.1 vs. 116.1 pg/ml, and high-mobility group protein 1 [HMGB1]: 323.7 vs. 449.3 ng/ml; all P< 0.05) and serum (TNF-β: 302.7 vs. 450.7 pg/ml, IL-1β: 51.7 vs. 96.7 pg/ml, IL-6: 390.4 vs. 722.5 pg/ml, and HMGB1: 592.2 vs. 985.4 ng/ml; all P< 0.05) in septic animals. In vitro experiments showed that the 0.5 MAC isoflurane in 60% oxygen reduced inflammatory responses in mouse RAW264.7 cells, after LPS stimulation (all P< 0.05). Suppressed activation of NF-κB pathway was also observed in mouse RAW264.7 macrophages and human PBMCs after LPS stimulation or plasma from septic patients. The 0.5 MAC isoflurane in 60% oxygen also prevented the increases of phospho-IKKβ/β, phospho-IκBβ, and phospho-p65 expressions in RAW264.7 macrophages after LPS stimulation (all P< 0.05).

CONCLUSION

Combined administration of a sedative dose of isoflurane with 60% oxygen improves survival of septic animals through reducing inflammatory responses.

Protective effect of sevoflurane preconditioning on ischemia-reperfusion injury in patients undergoing reconstructive plastic surgery with microsurgical flap, a randomized controlled trial

Background

In many clinical conditions that involve free flaps and tissue transplantations the possibility of minimizing ischemia-reperfusion injury can be a determinant factor for the success of the surgery itself. We hypothesize that preconditioning with sevoflurane is a protective factor against ischemia-reperfusion injury.

Methods

In this randomized controlled trial, patients ASA I-II undergoing breast reconstruction with deep inferior epigastric perforator flaps were allocated into two groups and analyzed: group BAL included patients who received balanced anesthesia with sevoflurane for 30 min before removal of the flap and throughout the surgery. The TCI group included patients who received a total intravenous anesthesia with propofol and remifentanil. We evaluated regional tissue oximetry at the end of the surgery and at 4, 12 and 20 h after surgery. Other assessed parameters were: blood lactate clearance, alanine aminotransferase, aspartate aminotransferase, lactic dehydrogenase, creatine phosphokinase.

Results

In total 54 patients, twenty-seven per group, were analyzed. There was a significant increase of the average value of regional tissue oximetry measured 4 h after surgery in the BAL group compared to the TCI group: BAL: 84.05 % (8.96 SD); TCI : 76.17 % (12.92 SD) (P = 0.03), but not at the other time frames. The creatine phosphokinase value was significantly lower in the BAL group at the end of surgery, but not at the other time-frames. There were no significant differences in blood levels of other markers.

Conclusions

From our results, the positive preconditioning impact of sevoflurane on ischemia-reperfusion injury in patients undergoing free flap surgery is expressed in the early postoperative hours, but it does not persist in the long-term.

Trial registration

ClinicalTrial.gov identifier: NCT01905501. Registered July 18, 2013

Histopathological and Biochemical Effects of Ecballium elaterium on Sepsis-Induced Lung Injury

PURPOSE

The aim of this study was to investigate the role of Ecballium elaterium (EE) on sepsis-induced lung injury.

MATERIALS AND METHODS

A total of 30 male rats were divided into three groups as follows: control, sepsis, and treatment groups (sepsis + EE) with each group containing 10 rats. A rat model of sepsis induced by cecal ligation and puncture (CLP) was used. In the treatment group, rats were injected intraperitoneally with 2.5 mg/kg EE after CLP. Interleukin-6 (IL-6), tumor necrosis factor (TNF)-α, total antioxidant status (TAS), total oxidant status (TOS), and oxidative stress index (OSI) values after a 24-hr period were measured via cardiac puncture. Animals were harvested after the procedure and biochemical analysis was done and histopathological changes of the tissue sections of lungs were examined thereafter.

RESULTS

A statistically significant decrease was observed in the IL-6 (p < .05), TNF-α (p < .05), and TOS (p < .01) levels in the sera of the treatment group compared to those of the sepsis group. Following the treatment, the TOS (p = .01) and OSI (p < .05) levels in the lung tissue of rats indicated a statistically significant decrease compared to those of the sepsis group. The histopathological follow-up undertaken after the administration of the EE treatment to septic rats showed significantly lower values of alveolar wall thickness (p < .001), interstitial edema (p = .018), and neutrophil infiltration (p = .047).

CONCLUSION

EE treatment may have beneficial effects on sepsis-induced lung injury, and therefore has potential for clinical use.

Desflurane preconditioning protects human umbilical vein endothelial cells against anoxia/reoxygenation by upregulating NLRP12 and inhibiting non-canonical nuclear factor-κB signaling

Volatile anesthetics modulate endothelial cell apoptosis and inhibit nuclear factor-κB (NF-κB) signaling. In this study, we aimed to assess whether desflurane preconditioning protects human umbilical vein endothelial cells (HUVECs) agaist anoxia/reoxygenation (A/R) injury. HUVECs were pre-conditioned with desflurane (1.0 MAC) for 30 min, followed by a 15-min washout, then exposed to 60 min anoxia and 60 min reoxygenation (A/R), and incubated with 10 ng/ml tumor necrosis factor (TNF)-α for 60 min. HUVEC viability and apoptosis were measured by MTT assay and annexin V staining, and immunoblot analysis was used to measure the levels of Smac and cellular inhibitor of apoptosis 1 (cIAP1). NF-κB activation was assessed using the NF-κB signaling pathway real‑time PCR array, and the levels of NF-κB inducing kinase (NIK), p52, IκB kinase (IKK)α, p100, RelB and NLR family, pyrin domain containing 12 (NLRP12) were assessed by immunoblot analysis. Desflurane preconditioning attenuated the effects of A/R and/or A/R plus TNF-α on cell viability, decreasing the levels of Smac and enhancing the levels of of cIAP1 (P<0.05). Preconditioning with desflurane also enhanced the mRNA levels of interleukin (IL)-10 and NLRP12 in the cells exposed to A/R by 2.40- and 2.16‑fold, respectively. The HUVECs exposed to A/R had greater levels of NIK and p100 and reduced levels of p52 and IKKα. Desflurance preconditioning further increased p100 levels, decreased the level of NIK, further decreased p52 levels and further reduced IKKα levels. A/R in combination with TNF-α increased the NIK, IKKα, p100 and RelB levels, and this increase was significantly attenuated by desflurance preconditioning (all P<0.05). Desflurane preconditioning enhanced HUVEC survival and protected the cells against A/R injury, and our results suggested that this process involved the upregulation of NLRP12 and the inhibition of non-canonical NF-κB signaling.

Effects of sevoflurane on ventilator induced lung injury in a healthy lung experimental model

INTRODUCTION AND OBJECTIVE

Ventilator-induced lung injury (VILI) causes a systemic inflammatory response in tissues, with an increase in IL-1, IL-6 and TNF-α in blood and tissues. Cytoprotective effects of sevoflurane in different experimental models are well known, and this protective effect can also be observed in VILI. The objective of this study was to assess the effects of sevoflurane in VILI.

MATERIAL AND METHODS

A prospective, randomized, controlled study was designed. Twenty female rats were studied. The animals were mechanically ventilated, without sevoflurane in the control group and sevoflurane 3% in the treated group (SEV group). VILI was induced applying a maximal inspiratory pressure of 35 cmH2O for 20 min without any positive end-expiratory pressure for 20 min (INJURY time). The animals were then ventilated 30 min with a maximal inspiratory pressure of 12 cmH2O and 3 cmH2O positive end-expiratory pressure (time 30 min POST-INJURY), at which time the animals were euthanized and pathological and biomarkers studies were performed. Heart rate, invasive blood pressure, pH, PaO2, and PaCO2 were recorded. The lung wet-to-dry weight ratio was used as an index of lung edema.

RESULTS

No differences were found in the blood gas analysis parameters or heart rate between the 2 groups. Blood pressure was statistically higher in the control group, but still within the normal clinical range. The percentage of pulmonary edema and concentrations of TNF-α and IL-6 in lung tissue in the SEV group were lower than in the control group.

CONCLUSIONS

Sevoflurane attenuates VILI in a previous healthy lung in an experimental subclinical model in rats.

Impact of Volatile Anesthetics on Oxidative Stress and Inflammation

The safety of anesthesia, which is an important step for surgery, can be determined by its impact on oxidative stress and inflammation. The effects of volatile anesthetics such as isoflurane and sevoflurane on oxidative stress and inflammation are reviewed in various (1) cell lines, (2) rodents, and (3) human studies. Isoflurane and sevoflurane are reported to have antioxidant and anti-inflammatory effects in all cells with exception of neuronal cell lines. In addition, various animal studies have indicated that isoflurane and sevoflurane were not only safe but also reduced oxidative stress and inflammation in rodent models. In human studies, oxidative stress, inflammation, and DNA damage were not affected by isoflurane and sevoflurane in patients undergoing minor incision surgeries. On the other hand, elevated oxidative stress, inflammation, and DNA damage have been observed in patients undergoing major surgeries such as abdominal and orthopedic surgeries, hysterectomy, cholecystectomy, and thoracotomy. Although impact of anesthetics on oxidative stress and inflammation is still not clear due to the variations of patients' health conditions, types of surgery and the quantities of anesthetics, isoflurane, and sevoflurane can be considered safe anesthetics with respect to their effect on oxidative stress and inflammation in subjects undergoing minor surgery. Continuous effort evaluating the safety of anesthesia in various aspects is required.

Sevoflurane ameliorates intestinal ischemia-reperfusion-induced lung injury by inhibiting the synergistic action between mast cell activation and oxidative stress

Preconditioning with sevoflurane (SEV) can protect against ischemia-reperfusion injury in several organs, however, the benefits of SEV against acute lung injury (ALI), induced by intestinal ischemia-reperfusion (IIR), and the underlying mechanisms remain to be elucidated. The present study was designed to investigate the effects of SEV preconditioning on IIR-mediated ALI and the associated mechanisms in a rat model. Female Sprague-Dawley rats treated with 2.3% SEV or apocynin (AP), an inhibitor of NADPH oxidase, were subjected to 75 min superior mesenteric artery occlusion followed by 2 h reperfusion in the presence or absence of the mast cell degranulator compound 48/80 (CP). SEV and AP were observed to downregulate the protein expression levels of p47^phox and gp91^phox in the lungs of normal rats. IIR resulted in severe lung injury, characterized by significant increases in pathological injury scores, lung wet/dry weight ratio, protein expression levels of p47^phox, gp91^phox and ICAM-1, the presence of hydrogen peroxide, malondydehyde and interleukin-6, and the activity of myeloperoxidase. In addition, significant reductions were observed in the expression of prosurfactant protein C, accompanied by an increase in MC degranulation, demonstrated by significant elevations in the number of mast cells, expression levels of tryptase and the concentration of β-hexosaminidase. These changes were further augmented in the presence of CP. In addition, SEV and AP preconditioning significantly alleviated the above alterations induced by IIR alone or in combination with CP. These findings suggested that SEV and AP attenuated IIR-induced ALI by inhibiting NADPH oxidase and the synergistic action between oxidative stress and mast cell activation.

Propofol increases morbidity and mortality in a rat model of sepsis

INTRODUCTION

Severe sepsis is associated with approximately 50% mortality and accounts for tremendous healthcare costs. Most patients require ventilatory support and propofol is commonly used to sedate mechanically ventilated patients. Volatile anesthetics have been shown to attenuate inflammation in a variety of different settings. We therefore hypothesized that volatile anesthetic agents may offer beneficial immunomodulatory effects during the course of long-term intra-abdominal sepsis in rats under continuous sedation and ventilation for up to 24 hours.

METHODS

Sham operation or cecal ligation and puncture (CLP) was performed in adult male Wistar rats followed by mechanical ventilation. Animals were sedated for 24 hours with propofol (7 to 20 mg/kg/h), sevoflurane, desflurane or isoflurane (0.7 minimal alveolar concentration each).

RESULTS

Septic animals sedated with propofol showed a mean survival time of 12 hours, whereas >56% of all animals in the volatile groups survived 24 hours (P <0.001). After 18 hours, base excess in propofol + CLP animals (-20.6 ± 2.0) was lower than in the volatile groups (isoflurane + CLP: -11.7 ± 4.2, sevoflurane + CLP: -11.8 ± 3.5, desflurane + CLP -14.2 ± 3.7; all P <0.03). Plasma endotoxin levels reached 2-fold higher levels in propofol + CLP compared to isoflurane + CLP animals at 12 hours (P <0.001). Also blood levels of inflammatory mediators (tumor necrosis factor-α, interleukin-1β, interleukin-10, CXCL-2, interferon-γ and high mobility group protein-1) were accentuated in propofol + CLP rats compared to the isoflurane + CLP group at the same time point (P <0.04).

CONCLUSIONS

This is the first study to assess prolonged effects of sepsis and long-term application of volatile sedatives compared to propofol on survival, cardiovascular, inflammatory and end organ parameters. Results indicate that volatile anesthetics dramatically improved survival and attenuate systemic inflammation as compared to propofol. The main mechanism responsible for adverse propofol effects could be an enhanced plasma endotoxin concentration, leading to profound hypotension, which was unresponsive to fluid resuscitation.

Pulmonary preconditioning, injury, and inflammation modulate expression of the candidate tumor suppressor gene ECRG4 in lung

PURPOSE

The human c2orf40 gene encodes a candidate tumor suppressor called Esophageal Cancer-Related Gene-4 (ECRG4) that is a cytokine-like epigenetically-regulated protein that is characteristically downregulated in cancer, injury, inflammation, and infection. Here, we asked whether ECRG4 gene expression is detectable in lung epithelial cells and if its expression changes with inflammation, infection, and/or protective preconditioning.

MATERIALS AND METHODS

We used immunoblotting, PCR, and quantitative PCR to measure ECRG4 and either inhalation anesthesia preconditioning, lipopolysaccharide injection, or laparotomy to modulate lung inflammation.

RESULTS

Immunoblotting establishes the presence of the full-length 14 kDa ECRG4 peptide in mouse lung. Immunohistochemistry localizes ECRG4 to type l alveolar epithelial cells. Basal ECRG4 mRNA is greater than TNF-α, IL-1β, and IL-6 but following inflammatory lung injury, TNF-α, IL-1β, IL-6, and IL-10 are upregulated while ECRG4 gene expression is decreased. Similar findings are observed after an intravenous administration of lipopolysaccharide. In contrast, lung preconditioning with isoflurane anesthesia increases lung ECRG4 gene expression. Over-expression of ECRG4 in human lung epithelial cells in vitro decreases cell proliferation implying that a loss of ECRG4 in vivo would be permissive to cell growth.

CONCLUSIONS

This study supports the hypothesis that ECRG4 acts as a sentinel growth inhibitor in lung alveolar epithelial cells. Its downregulation by injury, infection, and inflammation and upregulation by preconditioning supports a role for ECRG4 in regulating the alveolar epithelium response to injury and inflammation. By extension, the findings support a functional consequence to its inhibition by promoter hypermethylation (i.e. lung cancer) and suggest potential benefits to its upregulation.

The immune response to anesthesia: part 1

OBJECTIVE

To review the immune response to anesthesia including mechanical ventilation, inhaled anesthetic gases, and injectable anesthetics and sedatives.

STUDY DESIGN

Review.

METHODS AND DATABASES

Multiple literature searches were performed using PubMed and Google Scholar from spring 2012 through fall 2013. Relevant anesthetic and immune terms were used to search databases without year published or species constraints. The online database for Veterinary Anaesthesia and Analgesia and the Journal of Veterinary Emergency and Critical Care were searched by issue starting in 2000 for relevant articles.

CONCLUSION

Recent research data indicate that commonly used volatile anesthetic agents, such as isoflurane and sevoflurane, may have a protective effect on vital organs. With the lung as the target organ, protection using an appropriate anesthetic protocol may be possible during direct pulmonary insults, including mechanical ventilation, and during systemic disease processes, such as endotoxemia, generalized sepsis, and ischemia-reperfusion injury.

Xuebijing exerts protective effects on lung permeability leakage and lung injury by upregulating Toll-interacting protein expression in rats with sepsis

Xuebijing (XBJ) is a type of traditional Tibetan medicine, and previous pharmacological studies have shown that the ethanol extract is derived from Chuanxiong, Chishao, Danshen and Honghua. Chuanxiong, Chishao, Danshen and Honghua possesses potent anti-inflammatory activity, and has been used in the treatment of inflammatory infectious diseases. In the present study, we investigated the effects of XBJ on pulmonary permeability and lung injury in cecal ligation and puncture (CLP)-induced sepsis in rats. A CLP sepsis model was established for the control and treatment groups, respectively. Approximately 2 h prior to surgery, an amount of 100 mg/kg XBJ injection was administered to the treatment group. Reverse transcription polymerase chain reaction (PT-PCR) and western blot analysis were used to examine the expression of Toll-interacting protein (Tollip), interleukin-1 receptor-associated kinase 1 (IRAK1), Toll-like receptor 4 (TLR4), nuclear factor-κB65 (NF-κB65) and TNF receptor-associated factor 6 (TRAF6) in lung tissue. ELISA was applied to detect changes of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin-1 (IL-1), interleukin-4 (IL-4) and interleukin-10 (IL-10) levels in bronchoalveolar lavage (BAL) fluid, and intercellular adhesion molecule 1 (ICAM-1) and von Willebrand factor (vWF) in serum. The number of neutrophils, albumin and total cells in the BAL fluid were measured. For histological analysis, hematoxylin and eosin (H&E) stains were evaluated. Lung permeability, the wet/dry weight ratio (W/D) and the lung pathology score were determined following the induction of ALI by CLP for 24 h. The results demonstrated that XBJ upregulated Tollip expression and blocked the activity of IRAK1, TLR4, NF-κβ65 and TRAF6. Additionally, the number of neutrophils and total cells were significantly decreased in the XBJ group compared to that in the control group. Lung permeability, the wet/dry weight ratio (W/D) and the lung pathology score were significantly decreased in the XBJ group. The histological results also demonstrated the attenuation effect of XBJ on CLP-induced lung inflammation. The results of the present study indicated that XBJ has a significantly reduced CLP-induced lung permeability by upregulating Tollip expression. The protective effects of XBJ suggest its therapeutic potential in CLP-induced acute lung injury treatment.

Acute high-level exposure to WTC particles alters expression of genes associated with oxidative stress and immune function in the lung

First responders (FR) present at Ground Zero in the first 72 h after the World Trade Center (WTC) collapsed have progressively exhibited significant respiratory injuries. The few toxicology studies performed to date evaluated effects from just fine (< 2.5 µm) WTC dusts; none examined health effects/toxicities from atmospheres bearing larger particle sizes, despite the fact the majority (> 96%) of dusts were > 10 µm and most FR likely entrained dusts by mouth breathing. Using a system that generated/delivered supercoarse (10-53 µm) WTC dusts to F344 rats (in a manner that mimicked FR exposures), this study sought to examine potential toxicities in the lungs. In this exploratory study, rats were exposed for 2 h to 100 mg WTC dust/m(3) (while under isoflurane [ISO] anesthesia) or an air/ISO mixture; this dose conservatively modeled likely exposures by mouth-breathing FR facing ≈750-1000 mg WTC dust/m(3). Lungs were harvested 2 h post-exposure and total RNA extracted for subsequent global gene expression analysis. Among the >  1000 genes affected by WTC dust (under ISO) or ISO alone, 166 were unique to the dust exposure. In many instances, genes maximally-induced by the WTC dust exposure (relative to in naïve rats) were unchanged/inhibited by ISO only; similarly, several genes maximally inhibited in WTC dust rats were largely induced/unchanged in rats that received ISO only. These outcomes reflect likely contrasting effects of ISO and the WTC dust on lung gene expression. Overall, the data show that lungs of rats exposed to WTC dust (under ISO) - after accounting for any impact from ISO alone - displayed increased expression of genes related to lung inflammation, oxidative stress, and cell cycle control, while several involved in anti-oxidant function were inhibited. These changes suggested acute inflammogenic effects and oxidative stress in the lungs of WTC dust-exposed rats. This study, thus, concludes that a single very high exposure to WTC dusts could potentially have adversely affected the respiratory system - in terms of early inflammatory and oxidative stress processes. As these changes were not compared with other types of dusts, the uniqueness of these WTC-mediated effects remains to be confirmed. It also still remains to be determined if these effects might have any relevance to chronic lung pathologies that became evident among FR who encountered the highest dust levels on September 11, 2001 and the 2 days thereafter. Ongoing studies using longer-range post-exposure analyses (up to 1-year or more) will help to determine if effects seen here on genes were acute, reversible, or persistent, and associated with corresponding histopathologic/biochemical changes in situ.

Lung preconditioning in anesthesia: Review of the literature

Lung injury can arise during or after anesthesia and can lead to a complicated postoperative course with great implications for the patient. Unfortunately, treatment of acute lung injury is at the moment mainly supportive and rates of recovery have not really improved in the recent years. In many cases, lung injury can be anticipated and preventive measures seem possible. This represents a unique challenge to the anesthesiologist, as some new opportunities to reduce the frequency and/or severity of lung injury seem now available. These chances may arise from the potency of preconditioning the lungs before the main injury, with smaller injurious insults. Although preconditioning began to be applicated first on the myocardium, experimental studies have shown potentially beneficial results also for the lungs. This review summarizes the main methods of lung preconditioning that have been tried in experimental studies in the literature and the main mechanisms that are perhaps involved. Emphasis is given in the two main methods of preconditioning that seem readily applicable in the clinical praxis, that is ischemic preconditioning, as well as preconditioning with volatile anesthetics. The few, but interesting clinical studies are also summarized and the future research points in this evolving field of anesthesia are stressed.

The mechanism of sevoflurane preconditioning-induced protections against small intestinal ischemia reperfusion injury is independent of mast cell in rats

The study aimed to investigate whether sevoflurane preconditioning can protect against small intestinal ischemia reperfusion (IIR) injury and to explore whether mast cell (MC) is involved in the protections provided by sevoflurane preconditioning. Sprague-Dawley rats exposed to sevoflurane or treated with MC stabilizer cromolyn sodium (CS) were subjected to 75-minute superior mesenteric artery occlusion followed by 2-hour reperfusion in the presence or absence of MC degranulator compound 48/80 (CP). Small intestinal ischemia reperfusion resulted in severe intestinal injury as demonstrated by significant elevations in intestinal injury scores and p47^phox and gp91^phox, ICAM-1 protein expressions and malondialdehyde and IL-6 contents, and MPO activities as well as significant reductions in SOD activities, accompanied with concomitant increases in mast cell degranulation evidenced by significant increases in MC counts, tryptase expression, and β-hexosaminidase concentrations, and those alterations were further upregulated in the presence of CP. Sevoflurane preconditioning dramatically attenuated the previous IIR-induced alterations except MC counts, tryptase, and β-hexosaminidase which were significantly reduced by CS treatment. Furthermore, CP exacerbated IIR injury was abrogated by CS but not by sevoflurane preconditioning. The data collectively indicate that sevoflurane preconditioning confers protections against IIR injury, and MC is not involved in the protective process.

Volatile anesthetics-induced neuroinflammatory and anti-inflammatory responses

Volatile anesthetics have been the major anesthetics used clinically for more than 150 years. They provide all components of general anesthesia and are easy to be applied and monitored with modern equipment and technology. In addition to having anesthetic property, volatile anesthetics have multiple other effects. Many studies have clearly shown that volatile anesthetics can reduce systemic and local inflammatory responses induced by various stimuli in humans and animals. On the other hand, recent animal studies have shown that volatile anesthetics may induce mild neuroinflammation. These dual effects on inflammation may have significant biological implications and are briefly reviewed here.

Impact of Anesthetics on Immune Functions in a Rat Model of Vagus Nerve Stimulation

Vagus nerve stimulation (VNS) has been successfully performed in animals for the treatment of different experimental models of inflammation. The anti-inflammatory effect of VNS involves the release of acetylcholine by vagus nerve efferent fibers inhibiting pro-inflammatory cytokines (e.g. TNF-α) produced by macrophages. Moreover, it has recently been demonstrated that splenic lymphocytic populations may also be involved. As anesthetics can modulate the inflammatory response, the current study evaluated the effect of two different anesthetics, isoflurane and pentobarbital, on splenic cellular and molecular parameters in a VNS rat model. Spleens were collected for the characterization of lymphocytes sub-populations by flow cytometry and quantification of cytokines secretion after in vitro activation. Different results were observed depending on the anesthetic used. The use of isoflurane displayed a non-specific effect of VNS characterized by a decrease of most splenic lymphocytes sub-populations studied, and also led to a significantly lower TNF-α secretion by splenocytes. However, the use of pentobarbital brought to light immune modifications in non-stimulated animals that were not observed with isoflurane, and also revealed a specific effect of VNS, notably at the level of T lymphocytes’ activation. These differences between the two anesthetics could be related to the anti-inflammatory properties of isoflurane. In conclusion, pentobarbital is more adapted than isoflurane in the study of the anti-inflammatory effect of VNS on an anesthetized rat model in that it allows more accurate monitoring of subtle immunomodulatory processes.

Antioxidants that protect mitochondria reduce interleukin-6 and oxidative stress, improve mitochondrial function, and reduce biochemical markers of organ dysfunction in a rat model of acute sepsis

Background

Sepsis-induced organ failure is the major cause of death in critical care units, and is characterized by a massive dysregulated inflammatory response and oxidative stress. We investigated the effects of treatment with antioxidants that protect mitochondria (MitoQ, MitoE, or melatonin) in a rat model of lipopolysaccharide (LPS) plus peptidoglycan (PepG)-induced acute sepsis, characterized by inflammation, mitochondrial dysfunction and early organ damage.

Methods

Anaesthetized and ventilated rats received an i.v. bolus of LPS and PepG followed by an i.v. infusion of MitoQ, MitoE, melatonin, or saline for 5 h. Organs and blood were then removed for determination of mitochondrial and organ function, oxidative stress, and key cytokines.

Results

MitoQ, MitoE, or melatonin had broadly similar protective effects with improved mitochondrial respiration (P<0.002), reduced oxidative stress (P<0.02), and decreased interleukin-6 levels (P=0.0001). Compared with control rats, antioxidant-treated rats had lower levels of biochemical markers of organ dysfunction, including plasma alanine amino-transferase activity (P=0.02) and creatinine concentrations (P<0.0001).

Conclusions

Antioxidants that act preferentially in mitochondria reduce mitochondrial damage and organ dysfunction and decrease inflammatory responses in a rat model of acute sepsis.