Beatrice Beck-Schimmer

A randomized controlled trial on pharmacological preconditioning in liver surgery using a volatile anesthetic.

Objective:To evaluate the effects of pharmacological preconditioning with a volatile anesthetic in patients undergoing liver resection with inflow occlusion. Background:In liver surgery, ischemic preconditioning and intermittent clamping are the only established protective strategies to reduce tissue damage due to ischemia during inflow occlusion. Preconditioning with volatile anesthetics has provided protection against cardiac and renal ischemic injury in several animal models through NO and HO-1 pathways. But pharmacological preconditioning has never been tested in patients undergoing liver surgery in a randomized trial. Methods:Sixty-four patients undergoing liver surgery with inflow occlusion were randomized intraoperatively for preconditioning with sevoflurane or not (ClinicalTrials.gov NCT00516711). Anesthesia was performed intravenously with propofol. Thirty minutes before inflow occlusion propofol was replaced by sevoflurane in the preconditioning group. Primary endpoint was postoperative liver injury assessed by peak values of liver transaminases. Postoperative complications were recorded according to an established scoring system. Results:Sevoflurane preconditioning significantly limited the postoperative increase of serum transaminase levels by 261 U/L (95% CI, 65 to 458; P = 0.01) for the ALT and by 239 (95% CI, −2 to 480; P = 0.05) for the AST corresponding to decreases of baseline levels of 35% and 31%, respectively. Patients with steatosis had an even better benefit than patients without steatosis. The rates of any complication (risk ratio 0.46; 95% CI, 0.25 to 0.85; P = 0.006) and of severe complications requiring invasive procedures (risk ratio 0.25; 95% CI, 0.06 to 1.08; P = 0.05) were also lowered by preconditioning. Conclusion:This first randomized trial of pharmacological preconditioning in liver surgery in humans showed a protective effect of preconditioning with volatile anesthetics. This strategy may provide a new and easily applicable therapeutic option to protect the liver and to lower complication rates.

Anesthetic-induced improvement of the inflammatory response to one-lung ventilation.

Background:Although one-lung ventilation (OLV) has become an established procedure during thoracic surgery, sparse data exist about inflammatory alterations in the deflated, reventilated lung. The aim of this study was to prospectively investigate the effect of OLV on the pulmonary inflammatory response and to assess possible immunomodulatory effects of the anesthetics propofol and sevoflurane. Methods:Fifty-four adults undergoing thoracic surgery with OLV were randomly assigned to receive either anesthesia with intravenously applied propofol or the volatile anesthetic sevoflurane. A bronchoalveolar lavage was performed before and after OLV on the lung side undergoing surgery. Inflammatory mediators (tumor necrosis factor &agr;, interleukin 1&bgr;, interleukin 6, interleukin 8, monocyte chemoattractant protein 1) and cells were analyzed in lavage fluid as the primary endpoint. The clinical outcome determined by postoperative adverse events was assessed as the secondary endpoint. Results:The increase of inflammatory mediators on OLV was significantly less pronounced in the sevoflurane group. No difference in neutrophil recruitment was found between the groups. A positive correlation between neutrophils and mediators was demonstrated in the propofol group, whereas this correlation was missing in the sevoflurane group. The number of composite adverse events was significantly lower in the sevoflurane group. Conclusions:This prospective, randomized clinical study suggests an immunomodulatory role for the volatile anesthetic sevoflurane in patients undergoing OLV for thoracic surgery with significant reduction of inflammatory mediators and a significantly better clinical outcome (defined by postoperative adverse events) during sevoflurane anesthesia.

Alveolar macrophages regulate neutrophil recruitment in endotoxin-induced lung injury

BackgroundAlveolar macrophages play an important role during the development of acute inflammatory lung injury. In the present study, in vivo alveolar macrophage depletion was performed by intratracheal application of dichloromethylene diphosphonate-liposomes in order to study the role of these effector cells in the early endotoxin-induced lung injury.MethodsLipopolysaccharide was applied intratracheally and the inflammatory reaction was assessed 4 hours later. Neutrophil accumulation and expression of inflammatory mediators were determined. To further analyze in vivo observations, in vitro experiments with alveolar epithelial cells and alveolar macrophages were performed.ResultsA 320% increase of polymorphonuclear leukocytes in bronchoalveolar lavage fluid was observed in macrophage-depleted compared to macrophage-competent lipopolysaccharide-animals. This neutrophil recruitment was also confirmed in the interstitial space. Monocyte chemoattractant protein-1 concentration in bronchoalveolar lavage fluid was significantly increased in the absence of alveolar macrophages. This phenomenon was underlined by in vitro experiments with alveolar epithelial cells and alveolar macrophages. Neutralizing monocyte chemoattractant protein-1 in the airways diminished neutrophil accumulation.ConclusionThese data suggest that alveolar macorphages play an important role in early endotoxin-induced lung injury. They prevent neutrophil influx by controlling monocyte chemoattractant protein-1 production through alveolar epithelial cells. Alveolar macrophages might therefore possess robust anti-inflammatory effects.

Antimetastatic potential of amide-linked local anesthetics: inhibition of lung adenocarcinoma cell migration and inflammatory Src signaling independent of sodium channel blockade.

Background: Retrospective analysis of patients undergoing cancer surgery suggests the use of regional anesthesia may reduce cancer recurrence and improve survival. Amide-linked local anesthetics have antiinflammatory properties, although the mechanism of action in this regard is unclear. As inflammatory processes involving Src tyrosine protein kinase and intercellular adhesion molecule-1 are important in tumor growth and metastasis, we hypothesized that amide-linked local anesthetics may inhibit inflammatory Src-signaling involved in migration of adenocarcinoma cells. Methods: NCI-H838 lung cancer cells were incubated with tumor necrosis factor-&agr; in absence/presence of ropivacaine, lidocaine, or chloroprocaine (1 nM–100 &mgr;M). Cell migration and total cell lysate Src-activation and intercellular adhesion molecule-1 phosphorylation were assessed. The role of voltage-gated sodium-channels in the mechanism of local anesthetic effects was also evaluated. Results: Ropivacaine treatment (100 &mgr;M) of H838 cells for 20 min decreased basal Src activity by 62% (P = 0.003), and both ropivacaine and lidocaine coadministered with tumor necrosis factor-&agr; statistically significantly decreased Src-activation and intercellular adhesion molecule-1 phosphorylation, whereas chloroprocaine had no such effect. Migration of these cells at 4 h was inhibited by 26% (P = 0.005) in presence of 1 &mgr;M ropivacaine and 21% by 1 &mgr;M lidocaine (P = 0.004). These effects of ropivacaine and lidocaine were independent of voltage-gated sodium-channel inhibition. Conclusions: This study indicates that amide-, but not ester-linked, local anesthetics may provide beneficial antimetastatic effects. The observed inhibition of NCI-H838 cell migration by lidocaine and ropivacaine was associated with the inhibition of tumor necrosis factor-&agr;-induced Src-activation and intercellular adhesion molecule-1 phosphorylation, providing the first evidence of a molecular mechanism that appears to be independent of their known role as sodium-channel blockers.

Relationship of Acute Lung Inflammatory Injury to Fas/FasL System

There is mounting evidence that apoptosis plays a significant role in tissue damage during acute lung injury. To evaluate the role of the apoptosis mediators Fas and FasL in acute lung injury, Fas (lpr)- or FasL (gld)-deficient and wild-type mice were challenged with intrapulmonary deposition of IgG immune complexes. Lung injury parameters ((125)I-albumin leak, accumulation of myeloperoxidase, and wet lung weights) were measured and found to be consistently reduced in both lpr and gld mice. In wild-type mice, lung injury was associated with a marked increase in Fas protein in lung. Inflamed lungs of wild-type mice showed striking evidence of activated caspase-3, which was much diminished in inflamed lungs from lpr mice. Intratracheal administration of a monoclonal Fas-activating antibody (Jo2) in wild-type mice induced MIP-2 and KC production in bronchoalveolar lavage fluids, and a murine alveolar macrophage cell line (MH-S) showed significantly increased MIP-2 production after incubation with this antibody. Bronchoalveolar lavage fluid content of MIP-2 and KC was substantially reduced in lpr mice after lung injury when compared to levels in wild-type mice. These data suggest that the Fas/FasL system regulates the acute lung inflammatory response by positively affecting CXC-chemokine production, ultimately leading to enhanced neutrophil influx and tissue damage.

Role of alveolar epithelial ICAM-1 in lipopolysaccharide-induced lung inflammation

Intercellular adhesion molecule-1 (ICAM-1) is known to play a central role in lung inflammation. Limited information, however, is available regarding the expression and biological function of ICAM-1 in the alveolar epithelial compartment. The current report analyses the expression pattern of ICAM-1 in primary cultures of rat alveolar epithelial cells (AECs) and in the rat lung following instillation of bacterial endotoxin (lipopolysaccharide (LPS)) in order to better define the role of alveolar epithelial ICAM-1. AECs stimulated in vitro with LPS were evaluated for ICAM-1 and ICAM-1 messenger ribonucleic acid content. Adherence assays with neutrophils and macrophages were performed. Endotoxin-induced ICAM-1 upregulation on AECs was demonstrated in vivo by immunofluorescence staining. In addition, the effect of intratracheally-instilled anti-ICAM-1 was assessed. Significant upregulation of ICAM-1 occurred in vitro and in vivo on AECs after LPS stimulation. Adherence assays showed a 114% increase in adhesion of neutrophils to AECs. Antibody directed against ICAM-1 reduced this adhesion by 40%. A significant reduction in the number of neutrophils in bronchoalveolar lavage fluid and whole lung was seen under airway ICAM-1 blockade. These data indicate that intercellular adhesion molecule-1 participates in the inflammatory response to lipopolysaccharide-induced lung injury in the distal airways by interacting mainly with neutrophils.

Sevoflurane ameliorates gas exchange and attenuates lung damage in experimental lipopolysaccharide-induced lung injury.

Background:Acute lung injury is a common complication in critically ill patients. Several studies suggest that volatile anesthetics have immunomodulating effects. The aim of the current study was to assess possible postconditioning with sevoflurane in an in vivo model of endotoxin-induced lung injury. Methods:Rats were anesthetized, tracheotomized, and mechanically ventilated. Lipopolysaccharide (saline as control) was administered intratracheally. Upon injury after 2 h of propofol anesthesia, general anesthesia was continued with either sevoflurane or propofol for 4 h. Arterial blood gases were measured every 2 h. After 6 h of injury, bronchoalveolar lavage was performed and lungs were collected. Total cell count, albumin content, concentrations of the cytokines cytokine-induced neutrophil chemoattractant-1 and monocyte chemoattractant protein-1, and phospholipids were analyzed in bronchoalveolar lavage fluid. Expression of messenger RNA for the two cytokines and for surfactant protein B was determined in lung tissue. Histopathologic examination of the lung was performed. Results:Significant improvement of the ratio of oxygen tension to inspired oxygen fraction was shown with sevoflurane (mean ± SD: 243 ± 94 mmHg [32.4 kPa]) compared with propofol (88 ± 19 mmHg [11.7 kPa]). Total cell count representing effector cell recruitment as well as albumin content as a measure of lung permeability were significantly decreased in the sevoflurane–lipopolysaccharide group compared with the propofol–lipopolysaccharide group in bronchoalveolar lavage fluid. Expression of the cytokines protein in bronchoalveolar lavage fluid as well as messenger RNA in lung tissue was significantly lower in the sevoflurane–lipopolysaccharide group compared with the propofol–lipopolysaccharide group. Conclusions:Postconditioning with sevoflurane attenuates lung damage and preserves lung function in an in vivo model of acute lung injury.

Development and Validation of a Prediction Score for Postoperative Acute Renal Failure Following Liver Resection

Objective:To develop and validate a score to predict postoperative acute renal failure (ARF) after liver resection. Background:Postoperative ARF after major surgery is associated with morbidity and mortality. Early identification of patients at risk of ARF is important in order to provide protective kidney treatment. Methods:Postoperative ARF was prospectively assessed in consecutive patients undergoing liver resection. In randomly selected two-third of the total number of patients, multivariate logistic regression analysis was used to develop a new prediction score (including a full and a reduced model), based on the preoperative parameters of age, gender, preexisting chronic renal dysfunction, cardiovascular disease, diabetes, bilirubin, and alanine aminotransferase (ALT) levels. In the remaining last third of the patients, the new score was validated by calibrating the accuracy of the score (ClinicalTrials.gov NCT 00743132). Results:Postoperative ARF occurred in 15.1% (86 of 569 consecutive patients) from 2002 to 2007 and was highly associated with mortality (22.5% vs. 0.8% without ARF, P < 0.001). In the 380 (two-third of the population) patients selected for the development of the prediction score, preoperatively elevated ALT, preexisting cardiovascular disease, chronic renal failure, and diabetes were the strongest predictors of ARF. Validating the full prediction model (0–22 points) to the remaining 189 patients (one-third of the population), the risk could be predicted accurately (mean predicted risk of 11.5% vs. an observed risk of 14.8%) without significant differences between predicted and observed risks across different risk categories (P = 0.98). Prediction with the reduced model including the 4 strongest predictors (0–7 points) was almost as accurate as with the full model (11.4% predicted vs. 14.8% observed) and also without significant differences across different risk categories (P = 0.75). Conclusions:The new prediction score (the full as well as the reduced model) accurately predicted postoperative ARF after liver resection. The use of these scores allows early identification of patients at high risk of ARF, and may support decision making for protective kidney interventions perioperatively.

Ropivacaine decreases inflammation in experimental endotoxin-induced lung injury.

Background: Endotoxin causes acute lung injury, which can lead to acute respiratory distress syndrome. Because local anesthetics are known to attenuate inflammatory reactions, ropivacaine was tested for its possible antiinflammatory effect in lipopolysaccharide-induced lung injury in rat alveolar epithelial cells (AECs) and rat pulmonary artery endothelial cells (RPAECs) in vitro and in vivo. Methods: AECs and RPAECs were stimulated for 4 h with lipopolysaccharide or lipopolysaccharide and 1 μM ropivacaine. Messenger RNA (mRNA) for intercellular adhesion molecule 1 was assessed. Isolated neutrophils were incubated with stimulated target cells to quantify adhesion and neutrophil-induced cytotoxicity in AECs and RPAECs. In vivo, lipopolysaccharide was instilled intratracheally with or without 1 mM intratracheally or intravenously administered ropivacaine. Bronchoalveolar lavage was performed 5 h later to determine neutrophil and albumin content, as well as concentrations of inflammatory mediators. Results: In AECs and RPAECs, ropivacaine attenuated lipopolysaccharide-induced up-regulation of mRNA for intercellular adhesion molecule 1 by 41% and 24%, respectively (P < 0.05). In the presence of ropivacaine, increased neutrophil adhesion was down-regulated by 58% and 44% (P < 0.005), whereas cytotoxicity in AECs and RPAECs was diminished by 28% and 33%, respectively (P < 0.05). Enhanced neutrophil count in lipopolysaccharide lungs was reduced by 56% in the presence of intratracheally instilled ropivacaine (81% with intravenous ropivacaine; P < 0.005). Albumin was decreased by 46% with intratracheal ropivacaine (38% with intravenous ropivacaine; P < 0.05), and inflammatory mediators were decreased by 48-59% (69-81% with intravenous ropivacaine; P < 0.01). Conclusions: Ropivacaine intervention substantially attenuated the inflammatory response in acute lung injury and thus may carry an interesting potential for antiinflammatory treatment.

The immunomodulatory effect of sevoflurane in endotoxin-injured alveolar epithelial cells

BACKGROUND:Endotoxin-induced lung injury is a useful experimental system for the characterization of immunopathologic mechanisms in acute lung injury. Although alveolar epithelial cells (AEC) are directly exposed to volatile anesthetics, there is limited information about the effect of anesthetics on these cells. In this study we investigated the effect of pretreatment with the inhaled anesthetic sevoflurane on lipopolysaccharide (LPS)-injured AEC. METHODS:AEC were incubated with 1.1 vol % sevoflurane for 0.5 h, followed by LPS stimulation for 5 h. Expression of monocyte chemoattractant protein-1 (MCP-1), macrophage inflammatory protein-1β (MIP-1β), macrophage inflammatory protein-2 (MIP-2), cytokine-induced neutrophil chemoattractant-1 (CINC-1), and intercellular adhesion molecule-1 (ICAM-1) was analyzed. In addition, functional tests were performed through chemotaxis and adherence assays to underline the biological relevance of the findings. RESULTS:Exposure of AEC to sevoflurane resulted in a 50% downregulation of MCP-1 protein in the sevoflurane-LPS group when compared with non-sevoflurane- LPS cells (P < 0.05). MIP-1β concentration in LPS-stimulated cells decreased by 32% with sevoflurane (P < 0.05), MIP-2 by 29% (P < 0.05), and CINC-1 by 20% (P < 0.05). ICAM-1 protein expression was attenuated by 36% (P < 0.05). This inhibition caused substantial changes in the inflammatory response of neutrophils. 33% less chemotactic activity was seen in sevoflurane-treated LPS cells (P < 0.001) as well as 47% decreased adhesion of neutrophils to AEC (P < 0.001). CONCLUSIONS:This study shows that sevoflurane alters the LPS-induced inflammatory response, not only with respect to the expression pattern of inflammatory mediators, but also regarding the biological consequences with less accumulation of effector cells such as neutrophils.