A randomized controlled trial on pharmacological preconditioning in liver surgery using a volatile anesthetic. Ann Surg. 2008;248:909-918. [PMID: 19092335 DOI: 10.1097/sla.0b013e31818f3dda]

Economic Evaluation of Pharmacologic Pre- and Postconditioning With Sevoflurane Compared With Total Intravenous Anesthesia in Liver Surgery: A Cost Analysis

BACKGROUND

Pharmacologic pre- and postconditioning with sevoflurane compared with total IV anesthesia in patients undergoing liver surgery reduced complication rates as shown in 2 recent randomized controlled trials. However, the potential health economic consequences of these different anesthesia regimens have not yet been assessed.

METHODS

An expostcost analysis of these 2 trials in 129 patients treated between 2006 and 2010 was performed. We analyzed direct medical costs for in-hospital stay and compared pharmacologic pre- and postconditioning with sevoflurane (intervention) with total IV anesthesia (control) from the perspective of a Swiss university hospital. Year 2015 costs, converted to US dollars, were derived from hospital cost accounting data and compared with a multivariable regression analysis adjusting for relevant covariables. Costs with negative prefix indicate savings and costs with positive prefix represent higher spending in our analysis.

RESULTS

Treatment-related costs per patient showed a nonsignificant change by -12,697 US dollars (95% confidence interval [CI], 10,956 to -36,352; P = .29) with preconditioning and by -6139 US dollars (95% CI, 6723 to -19,000; P = .35) with postconditioning compared with the control group. Results were robust in our sensitivity analysis. For both procedures (control and intervention) together, major complications led to a significant increase in costs by 86,018 US dollars (95% CI, 13,839-158,198; P = .02) per patient compared with patients with no major complications.

CONCLUSIONS

In this cost analysis, reduced in-hospital costs by pharmacologic conditioning with sevoflurane in patients undergoing liver surgery are suggested. This possible difference in costs compared with total IV anesthesia is the result of reduced complication rates with pharmacologic conditioning, because major complications have significant cost implications.

Lidocaine Administration Controls MicroRNAs Alterations Observed After Lung Ischemia-Reperfusion Injury

BACKGROUND

Ischemia-reperfusion injury (IRI) is associated with morbidity and mortality. MicroRNAs (miRNAs) have emerged as regulators of IRI, and they are involved in the pathogenesis of organ rejection. Lidocaine has proven anti-inflammatory activity in several tissues but its modulation of miRNAs has not been investigated. This work aims to investigate the involvement of miRNAs in lung IRI in a lung auto-transplantation model and to investigate the effect of lidocaine.

METHODS

Three groups (sham, control, and Lidocaine), each comprising 6 pigs, underwent a lung autotransplantation. All groups received the same anesthesia. In addition, animals of lidocaine group received a continuous intravenous administration of lidocaine (1.5 mg/kg/h) during surgery. Lung biopsies were taken before pulmonary artery clamp, before reperfusion, 30 minutes postreperfusion (Rp-30), and 60 minutes postreperfusion (Rp-60). Samples were analyzed for different miRNAs (miR-122, miR-145, miR-146a, miR-182, miR-107, miR-192, miR-16, miR-21, miR-126, miR-127, miR142-5p, miR152, miR155, miR-223, and let7) via the use of reverse-transcription quantitative polymerase chain reaction. Results were normalized with miR-103.

RESULTS

The expression of miR-127 and miR-16 did not increase after IRI. Let-7d, miR-21, miR-107, miR-126, miR-145, miR-146a, miR-182, and miR-192 significantly increased at the Rp-60 (control versus sham P < .001). miR-142-5p, miR-152, miR-155, and miR 223 significantly increased at the Rp-30 (control versus sham P < .001) and at the Rp-60 (control versus. sham P < .001). The administration of lidocaine was able to attenuate these alterations in a significant way (control versus Lidocaine P < .001).

CONCLUSIONS

Lung IRI caused dysregulation miRNA. The administration of lidocaine reduced significantly miRNAs alterations.

Volatile Anesthetics. Is a New Player Emerging in Critical Care Sedation?

Volatile anesthetic agent use in the intensive care unit, aided by technological advances, has become more accessible to critical care physicians. With increasing concern over adverse patient consequences associated with our current sedation practice, there is growing interest to find non-benzodiazepine-based alternative sedatives. Research has demonstrated that volatile-based sedation may provide superior awakening and extubation times in comparison with current intravenous sedation agents (propofol and benzodiazepines). Volatile agents may possess important end-organ protective properties mediated via cytoprotective and antiinflammatory mechanisms. However, like all sedatives, volatile agents are capable of deeply sedating patients, which can have respiratory depressant effects and reduce patient mobility. This review seeks to critically appraise current volatile use in critical care medicine including current research, technical consideration of their use, contraindications, areas of controversy, and proposed future research topics.

Sevoflurane Attenuates Ischemia-Reperfusion Injury in a Rat Lung Transplantation Model

BACKGROUND

Sevoflurane is one of the most commonly used volatile anesthetic agents with the fastest onset and offset, replacing isoflurane in modern anesthesiology. Preconditioning and postconditioning using volatile anesthetics can attenuate ischemia-reperfusion injury (IRI). However, no previous studies have evaluated the effect of sevoflurane in lung transplantation after cold ischemic injury. We aimed to study the effects of donor and recipient treatment with sevoflurane in a rat lung transplantation model.

METHODS

Lewis rats were allocated to four groups: control, PreC (preconditioning), PostC (postconditioning), and PreC + PostC. Donor rats in the PreC and PreC + PostC groups were exposed to 1.5% sevoflurane for 30 minutes before donor operation. Donor lungs were flushed with Perfadex and stored for 12 hours at 4°C before transplantation. Recipients received orthotopic left lung transplantation. In the PostC and PreC + PostC groups, sevoflurane was initiated 2 minutes before reperfusion and maintained for 30 minutes. Two hours after reperfusion, lung function was evaluated, and samples were collected for histologic, inflammatory, and cell death assessment.

RESULTS

Preconditioning and postconditioning using sevoflurane significantly improved the oxygenation of lung grafts (partial arterial gas pressure of oxygen: 198 mm Hg in control, 406.5 mm Hg in PreC, 472.4 mm Hg in PostC, and 409.7 mm Hg in PreC + PostC, p < 0.0001) and reduced pulmonary edema. Sevoflurane treatment reduced levels of interleukin-1β, interleukin-6, and tumor necrosis factor-α. Moreover, sevoflurane significantly inhibited apoptotic cells by a decrease in cytochrome c release into cytosol and caspase-3 cleavage.

CONCLUSIONS

Preconditioning or postconditioning of lungs using sevoflurane exhibits a significant protective effect against early phase of ischemia-reperfusion injury in a rat lung transplantation model.

Noteworthy Literature Published in 2016 for Abdominal Organ Transplantation Anesthesiologists

More than 3000 peer-reviewed publications on the topic of liver transplantation were published in 2016. The goal of this article is to provide a concise review of pertinent literature for anesthesiologists who participate in liver transplantation. The authors selected and presented 33 articles published in 2016 on the topics of MELD policy; cardiovascular, pulmonary, and renal issues; coagulation and transfusion; anesthetic agents; hemodynamic monitors; acute liver failure; and donor issues.

Melatonin pretreatment enhances the therapeutic effects of exogenous mitochondria against hepatic ischemia-reperfusion injury in rats through suppression of mitochondrial permeability transition

We tested the hypothesis that melatonin (Mel) enhances exogenous mitochondria (Mito) treatment against rodent hepatic ischemia-reperfusion (IR) injury. In vitro study utilized three groups of hepatocytes (i.e. nontreatment, menadione, and menadione-melatonin treatment, 4.0 × 10(5) each), while in vivo study used adult male Sprague Dawley rats (n = 40) equally divided into sham-control (SC), IR (60-min left-lobe ischemia + 72-hr reperfusion), IR-Mel (melatonin at 30 min/6/8 hr after reperfusion), IR-Mito (mitochondria 15,000 μg/rat 30 min after reperfusion), and IR-Mel-Mito. Following menadione treatment in vitro, oxidative stress (NOX-1/NOX-2/oxidized protein), apoptotic (cleaved caspase-3/PARP), DNA damage (γ-H2AX/CD90/XRCC1), mitochondria damage (cytosolic cytochrome c) biomarkers, and mitochondrial permeability transition were found to be lower, whereas mitochondrial cytochrome c were found to be higher in hepatocytes with melatonin treatment compared to those without (all P < 0.001). In vivo study demonstrated highest liver injury score and serum AST in IR group, but lowest in SC group and higher in IR-Mito group than that in groups IR-Mel and IR-Mel-Mito, and higher in IR-Mel group than that in IR-Mel-Mito group after 72-hr reperfusion (all P < 0.003). Protein expressions of inflammatory (TNF-α/NF-κB/IL-1β/MMP-9), oxidative stress (NOX-1/NOX-2/oxidized protein), apoptotic (caspase-3/PARP/Bax), and mitochondria damage (cytosolic cytochrome c) biomarkers displayed an identical pattern, whereas mitochondria integrity marker (mitochondrial cytochrome c) showed an opposite pattern compared to that of liver injury score (all P < 0.001) among five groups. Microscopically, expressions of apoptotic nuclei, inflammatory (MPO(+) /CD68(+) /CD14(+) cells), and DNA damage (γ-H2AX(+) cells) biomarkers exhibited an identical pattern compared to that of liver injury score (all P < 0.001) among five groups. Melatonin-supported mitochondria treatment offered an additional benefit of alleviating hepatic IR injury.

Which Anesthesia Regimen Is Best to Reduce Morbidity and Mortality in Lung Surgery?

Background

One-lung ventilation during thoracic surgery is associated with hypoxia–reoxygenation injury in the deflated and subsequently reventilated lung. Numerous studies have reported volatile anesthesia–induced attenuation of inflammatory responses in such scenarios. If the effect also extends to clinical outcome is yet undetermined. We hypothesized that volatile anesthesia is superior to intravenous anesthesia regarding postoperative complications.

Methods

Five centers in Switzerland participated in the randomized controlled trial. Patients scheduled for lung surgery with one-lung ventilation were randomly assigned to one of two parallel arms to receive either propofol or desflurane as general anesthetic. Patients and surgeons were blinded to group allocation. Time to occurrence of the first major complication according to the Clavien-Dindo score was defined as primary (during hospitalization) or secondary (6-month follow-up) endpoint. Cox regression models were used with adjustment for prestratification variables and age.

Results

Of 767 screened patients, 460 were randomized and analyzed (n = 230 for each arm). Demographics, disease and intraoperative characteristics were comparable in both groups. Incidence of major complications during hospitalization was 16.5% in the propofol and 13.0% in the desflurane groups (hazard ratio for desflurane vs. propofol, 0.75; 95% CI, 0.46 to 1.22; P = 0.24). Incidence of major complications within 6 months from surgery was 40.4% in the propofol and 39.6% in the desflurane groups (hazard ratio for desflurane vs. propofol, 0.95; 95% CI, 0.71 to 1.28; P = 0.71).

Conclusions

This is the first multicenter randomized controlled trial addressing the effect of volatile versus intravenous anesthetics on major complications after lung surgery. No difference between the two anesthesia regimens was evident.

Propofol but not sevoflurane prevents mitochondrial dysfunction and oxidative stress by limiting HIF-1α activation in hepatic ischemia/reperfusion injury

Mitochondrial dysfunction, reactive oxygen species (ROS) production and oxidative stress during reperfusion are determinant in hepatic ischemia/reperfusion (I/R) injury but may be impacted by different anesthetic agents. Thus, we aimed at comparing the effects of inhaled sevoflurane or intravenous propofol anesthesia on liver mitochondria in a rodent model of hepatic I/R injury. To this, male Wistar rats underwent I/R surgery using sevoflurane or propofol. In the I/R model, propofol limited the raise in serum aminotransferase levels as compared to sevoflurane. Mitochondrial oxygen uptake, respiratory activity, membrane potential and proton leak were altered in I/R; however, this impairment was significantly prevented by propofol but not sevoflurane. In addition, differently from sevoflurane, propofol limited hepatic I/R-induced mitochondria H2O2 production rate, free radical leak and hydroxynonenal-protein adducts levels. The I/R group anesthetized with propofol also showed a better recovery of hepatic ATP homeostasis and conserved integrity of mitochondrial PTP. Moreover, hypoxia-inducible factor 1 alpha (HIF-1α) expression was limited in such group. By using a cell model of desferoxamine-dependent HIF activation, we demonstrated that propofol was able to inhibit apoptosis and mitochondrial depolarization associated to HIF-1α action. In conclusion, hepatic I/R injury induces mitochondrial dysfunction that is not prevented by inhaled sevoflurane. On the contrary, propofol reduces liver damage and mitochondrial dysfunction by preserving respiratory activity, membrane potential and energy homeostasis, and limiting free radicals production as well as PTP opening. These hepatoprotective effects may involve the inhibition of HIF-1α.

Beyond Preconditioning: Postconditioning as an Alternative Technique in the Prevention of Liver Ischemia-Reperfusion Injury

Liver ischemia/reperfusion injury may significantly compromise hepatic postoperative function. Various hepatoprotective methods have been improvised, aiming at attenuating IR injury. With ischemic preconditioning (IPC), the liver is conditioned with a brief ischemic period followed by reperfusion, prior to sustained ischemia. Ischemic postconditioning (IPostC), consisting of intermittent sequential interruptions of blood flow in the early phase of reperfusion, seems to be a more feasible alternative than IPC, since the onset of reperfusion is more predictable. Regarding the potential mechanisms involved, it has been postulated that the slow intermittent oxygenation through controlled reperfusion decreases the burst production of oxygen free radicals, increases antioxidant activity, suppresses neutrophil accumulation, and modulates the apoptotic cascade. Additionally, favorable effects on mitochondrial ultrastructure and function, and upregulation of the cytoprotective properties of nitric oxide, leading to preservation of sinusoidal structure and maintenance of blood flow through the hepatic circulation could also underlie the protection afforded by postconditioning. Clinical studies are required to show whether biochemical and histological improvements afforded by the reperfusion/reocclusion cycles of postconditioning during early reperfusion can be translated to a substantial clinical benefit in liver resection and transplantation settings or to highlight more aspects of its molecular mechanisms.

Effects of Volatile Anesthetics on Mortality and Postoperative Pulmonary and Other Complications in Patients Undergoing Surgery

Background

It is not known whether modern volatile anesthetics are associated with less mortality and postoperative pulmonary or other complications in patients undergoing general anesthesia for surgery.

Methods

A systematic literature review was conducted for randomized controlled trials fulfilling following criteria: (1) population: adult patients undergoing general anesthesia for surgery; (2) intervention: patients receiving sevoflurane, desflurane, or isoflurane; (3) comparison: volatile anesthetics versus total IV anesthesia or volatile anesthetics; (4) reporting on: (a) mortality (primary outcome) and (b) postoperative pulmonary or other complications; (5) study design: randomized controlled trials. The authors pooled treatment effects following Peto odds ratio (OR) meta-analysis and network meta-analysis methods.

Results

Sixty-eight randomized controlled trials with 7,104 patients were retained for analysis. In cardiac surgery, volatile anesthetics were associated with reduced mortality (OR = 0.55; 95% CI, 0.35 to 0.85; P = 0.007), less pulmonary (OR = 0.71; 95% CI, 0.52 to 0.98; P = 0.038), and other complications (OR = 0.74; 95% CI, 0.58 to 0.95; P = 0.020). In noncardiac surgery, volatile anesthetics were not associated with reduced mortality (OR = 1.31; 95% CI, 0.83 to 2.05, P = 0.242) or lower incidences of pulmonary (OR = 0.67; 95% CI, 0.42 to 1.05; P = 0.081) and other complications (OR = 0.70; 95% CI, 0.46 to 1.05; P = 0.092).

Conclusions

In cardiac, but not in noncardiac, surgery, when compared to total IV anesthesia, general anesthesia with volatile anesthetics was associated with major benefits in outcome, including reduced mortality, as well as lower incidence of pulmonary and other complications. Further studies are warranted to address the impact of volatile anesthetics on outcome in noncardiac surgery.

Hepatic ischemia reperfusion injury: A systematic review of literature and the role of current drugs and biomarkers

Hepatic ischemia reperfusion injury (IRI) is not only a pathophysiological process involving the liver, but also a complex systemic process affecting multiple tissues and organs. Hepatic IRI can seriously impair liver function, even producing irreversible damage, which causes a cascade of multiple organ dysfunction. Many factors, including anaerobic metabolism, mitochondrial damage, oxidative stress and secretion of ROS, intracellular Ca(2+) overload, cytokines and chemokines produced by KCs and neutrophils, and NO, are involved in the regulation of hepatic IRI processes. Matrix Metalloproteinases (MMPs) can be an important mediator of early leukocyte recruitment and target in acute and chronic liver injury associated to ischemia. MMPs and neutrophil gelatinase-associated lipocalin (NGAL) could be used as markers of I-R injury severity stages. This review explores the relationship between factors and inflammatory pathways that characterize hepatic IRI, MMPs and current pharmacological approaches to this disease.

Nonalcoholic Fatty Liver Disease: Key Considerations Before and After Liver Transplantation

Nonalcoholic fatty liver disease (NAFLD) is the most common etiology of chronic liver disease in developed countries and is on trajectory to become the leading indication for liver transplantation in the USA and much of the world. Patients with NAFLD cirrhosis awaiting liver transplant face unique challenges and increased risk for waiting list stagnation and dropout due to burdensome comorbidities including obesity, diabetes, cardiovascular disease, and kidney disease. Thus far, patients transplanted for NAFLD cirrhosis have excellent mid- and long-term patient and graft survival, but concerns regarding short-term morbidity and mortality continue to exist. Post-liver transplantation, NAFLD occurs as both a recurrent and de novo manifestation, each with unique outcomes. NAFLD in the donor population is of concern given the growing demand for liver transplantation and mounting pressure to expand the donor pool. This review addresses key issues surrounding NAFLD as an indication for transplantation, including its increasing prevalence, unique patient demographics, outcomes related to liver transplantation, development of post-liver transplantation NAFLD, and NAFLD in the liver donor population. It also highlights exciting areas where further research is needed, such as the role of bariatric surgery and preconditioning of marginal donor grafts.

Incidence and risk factors for early renal dysfunction after liver transplantation

AIM: To determine renal dysfunction post liver transplantation, its incidence and risk factors in patients from a Belgian University Hospital.

METHODS: Orthotopic liver transplantations performed from January 2006 until September 2012 were retrospectively reviewed (n = 187). Patients with no renal replacement therapy (RRT) before transplantation were classified into four groups according to their highest creatinine plasma level during the first postoperative week. The first group had a peak creatinine level below 12 mg/L, the second group between 12 and 20 mg/L, the third group between 20 and 35 mg/L, and the fourth above 35 mg/L. In addition, patients who needed RRT during the first week after transplantation were also classified into the fourth group. Perioperative parameters were recorded as risk factors, namely age, sex, body mass index (BMI), length of preoperative hospital stay, prior bacterial infection within one month, preoperative ascites, preoperative treatment with β-blocker, angiotensin-converting enzyme inhibitor or non steroidal anti-inflammatory drugs, preoperative creatinine and bilirubin levels, donor status (cardiac death or brain death), postoperative lactate level, need for intraoperative vasopressive drugs, surgical revision, mechanical ventilation for more than 24 h, postoperative bilirubin and transaminase peak levels, postoperative hemoglobin level, amount of perioperative blood transfusions and type of immunosuppression. Univariate and multivariate analysis were performed using logistic ordinal regression method. Post hoc analysis of the hemostatic agent used was also done.

RESULTS: There were 78 patients in group 1 (41.7%), 46 in group 2 (24.6%), 38 in group 3 (20.3%) and 25 in group 4 (13.4%). Twenty patients required RRT: 13 (7%) during the first week after transplantation. Using univariate analysis, the severity of renal dysfunction was correlated with presence of ascites and prior bacterial infection, preoperative bilirubin, urea and creatinine level, need for surgical revision, use of vasopressor, postoperative mechanical ventilation, postoperative bilirubin and urea, aspartate aminotransferase (ASAT), and hemoglobin levels and the need for transfusion. The multivariate analysis showed that BMI (OR = 1.1, P = 0.004), preoperative creatinine level (OR = 11.1, P < 0.0001), use of vasopressor (OR = 3.31, P = 0.0002), maximal postoperative bilirubin level (OR = 1.44, P = 0.044) and minimal postoperative hemoglobin level (OR = 0.059, P = 0.0005) were independent predictors of early post-liver transplantation renal dysfunction. Neither donor status nor ASAT levels had significant impact on early postoperative renal dysfunction in multivariate analysis. Absence of renal dysfunction (group 1) was also predicted by the intraoperative hemostatic agent used, independently of the extent of bleeding and of the preoperative creatinine level.

CONCLUSION: More than half of receivers experienced some degree of early renal dysfunction after liver transplantation. Main predictors were preoperative renal dysfunction, postoperative anemia and vasopressor requirement.

Protective effects of sevoflurane in hepatic ischemia-reperfusion injury

The endothelial glycocalyx plays a critical role in the regulation of vascular structure and functions. Previous studies have demonstrated that sevoflurane, a volatile anesthetic, can preserve the endothelial glycocalyx in heart tissues against ischemia-reperfusion injury. However, little is known about the effects of sevoflurane pretreatment on the vascular structure and functions of liver tissues following ischemia-reperfusion injury. To this end, female Sprague-Dawley rats (n = 28) were anesthetized either with ketamine (80-120 mg/kg, i.p.) or with one minimum alveolar concentration (MAC) sevoflurane (2% v/v). Following in vivo hepatic ischemia procedure, the liver was isolated and reperfusion was produced. During the period of reperfusion, liver reperfusion samples were collected, and the concentrations of heparan sulfate and syndecan-1 (Syn-1), and the levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) enzymes, were measured. The morphology of hepatocytes and endothelial glycocalyx were then assessed by using the light and electron microscopies, respectively. Ischemia-reperfusion increased the release of HS and Syn-1, and elevated the levels of ALT and AST in a time-dependent manner. However, sevoflurane pretreatment reduced the release of HS and Syn-1and attenuated the levels of ALT and AST, in a time-dependent manner, as compared with ketamine pretreatment. Furthermore, sevoflurane pretreatment decreased the shedding of endothelial glycocalyx and hepatocytes necrosis. Sevoflurane pretreatment preserved the endothelial glycocalyx in the liver tissue against ischemia-reperfusion injury. The effect appears to help protect hepatocytes against ischemia-reperfusion-induced necrosis.

Protective effect of sevoflurane on hepatic ischaemia/reperfusion injury in the rat: A dose-response study

BACKGROUND

Ischaemia/reperfusion injury is a common problem in hepatic surgery. An appreciation of the role of sevoflurane dose in preconditioning and subsequent hepatoprotection against ischaemia/reperfusion injury would be useful.

OBJECTIVE

The aim of current study was to investigate the protective effect of sevoflurane preconditioning at different doses on hepatic ischaemia/reperfusion injury in rats.

DESIGN

Randomised, controlled, laboratory study.

SETTING

The Department of Anaesthesiology, The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai, Guangdong, China.

PARTICIPANTS

Fifty male Sprague-Dawley rats weighing 200 to 250 g, randomly assigned to five groups.

INTERVENTIONS

Control group (sham surgery, no ischaemia/reperfusion), I/R group (ischaemia/reperfusion but no sevoflurane pretreatment), S1 [1 minimum alveolar concentration (MAC) = 2.4%], S2 (1.5 MAC = 3.6%) and S3 (2 MAC = 4.8%) groups with sevoflurane pretreatment, respectively, followed by 60 min ischaemia and 120 min reperfusion.

MAIN OUTCOME MEASURES

At the end of reperfusion, serum levels of alanine aminotransferase and aspartate aminotransferase as well as superoxide dismutase activity, myeloperoxidase and malondialdehyde content in the liver were determined. Histological examination of the liver was also performed.

RESULTS

Serum levels of aspartate aminotransferase and alanine aminotransferase in the sevoflurane groups were significantly reduced compared to the elevated levels seen in the I/R group (P < 0.05). In the liver, the I/R-induced increase in myeloperoxidase activity and malondialdehyde level were significantly reduced by all sevoflurane concentrations (P < 0.05). The decrease in superoxide dismutase activity induced by I/R was prevented by all sevoflurane pretreatments (P < 0.05). No significant differences between the S1, S2 and S3 groups were seen in any of the above variables.

CONCLUSION

Sevoflurane pretreatment exerts a protective effect on hepatic ischaemia/reperfusion injury but there is no significant dose-response relationship in the concentration range used. It is possible that a dose-response relationship might exist at lower concentrations.

Mitochondrial Dysfunction and Autophagy in Hepatic Ischemia/Reperfusion Injury

Ischemia/reperfusion (I/R) injury remains a major complication of liver resection, transplantation, and hemorrhagic shock. Although the mechanisms that contribute to hepatic I/R are complex and diverse involving the interaction of cell injury in hepatocytes, immune cells, and endothelium, mitochondrial dysfunction is a cardinal event culminating in hepatic reperfusion injury. Mitochondrial autophagy, so-called mitophagy, is a key cellular process that regulates mitochondrial homeostasis and eliminates damaged mitochondria in a timely manner. Growing evidence accumulates that I/R injury is attributed to defective mitophagy. This review aims to summarize the current understanding of autophagy and its role in hepatic I/R injury and highlight the various therapeutic approaches that have been studied to ameliorate injury.

Anti-inflammatory liposomes have no impact on liver regeneration in rats

INTRODUCTION

Surgical resection is the gold standard in treatment of hepatic malignancies, giving the patient the best chance to be cured. The liver has a unique capacity to regenerate. However, an inflammatory response occurs during resection, in part mediated by Kupffer cells, that influences the speed of regeneration. The aim of this study was to investigate the effect of a Kupffer cell targeted anti-inflammatory treatment on liver regeneration in rats.

METHODS

Two sets of animals, each including four groups of eight rats, were included. Paired groups from each set received treatment with placebo, low dose dexamethasone, high dose dexamethasone or low dose anti-CD163 dexamethasone. Subsequently, the rats underwent 70% partial hepatectomy. The two sets were evaluated on postoperative day 2 or 5, respectively. Blood was drawn for circulating markers of inflammation and liver cell damage; liver tissue was sampled for analysis of regeneration rate and proliferation index.

RESULTS

The high dose dexamethasone group had significantly lower body and liver weight than the placebo and anti-CD163-dex groups. There were no differences in liver regeneration rates between groups. Hepatocyte proliferation was completed faster in the placebo group, although this was not significant. The anti-CD163-dex group showed increased blood levels of albumin and alanine aminotransferase and a diminished inflammatory response in terms of significantly reduced haptoglobin, α2-macroglobulin and Interleukine-6.

CONCLUSION

Low dose dexamethasone targeted to Kupffer cells does not affect histological liver cell regeneration after 70% hepatectomy in rats, but reduces the inflammatory response judged by circulating markers of inflammation.

Strategies to optimize the use of marginal donors in liver transplantation

Liver transplantation is the treatment of choice for end stage liver disease, but availability of liver grafts is still the main limitation to its wider use. Extended criteria donors (ECD) are considered not ideal for several reasons but their use has dramatically grown in the last decades in order to augment the donor liver pool. Due to improvement in surgical and medical strategies, results using grafts from these donors have become acceptable in terms of survival and complications; nevertheless a big debate still exists regarding their selection, discharge criteria and allocation policies. Many studies analyzed the use of these grafts from many points of view producing different or contradictory results so that accepted guidelines do not exist and the use of these grafts is still related to non-standardized policies changing from center to center. The aim of this review is to analyze every step of the donation-transplantation process emphasizing all those strategies, both clinical and experimental, that can optimize results using ECD.

Conditioning With Sevoflurane in Liver Transplantation: Results of a Multicenter Randomized Controlled Trial

BACKGROUND

During times of organ scarcity and extended use of liver grafts, protective strategies in transplantation are gaining importance. We demonstrated in the past that volatile anesthetics such as sevoflurane attenuate ischemia-reperfusion injury during liver resection. In this randomized study, we examined if volatile anesthetics have an effect on acute graft injury and clinical outcomes after liver transplantation.

METHODS

Cadaveric liver transplant recipients were enrolled from January 2009 to September 2012 at 3 University Centers (Zurich/Sao Paulo/Ghent). Recipients were randomly assigned to propofol (control group) or sevoflurane anesthesia. Postoperative peak of aspartate transaminase was defined as primary endpoint, secondary endpoints were early allograft dysfunction, in-hospital complications, intensive care unit, and hospital stay.

RESULTS

Ninety-eight recipients were randomized to propofol (n = 48) or sevoflurane (n = 50). Median peak aspartate transaminase after transplantation was 925 (interquartile range, 512-3274) in the propofol and 1097 (interquartile range, 540-2633) in the sevoflurane group. In the propofol arm, 11 patients (23%) experienced early allograft dysfunction, 7 (14%) in the sevoflurane one (odds ratio, 0.64 (0.20 to 2.02, P = 0.45). There were 4 mortalities (8.3%) in the propofol and 2 (4.0%) in the sevoflurane group. Overall and major complication rates were not different. An effect on clinical outcomes was observed favoring the sevoflurane group (less severe complications), but without significance.

CONCLUSIONS

This first multicenter trial comparing propofol with sevoflurane anesthesia in liver transplantation shows no difference in biochemical markers of acute organ injury and clinical outcomes between the 2 regimens. Sevoflurane has no significant added beneficial effect on ischemia-reperfusion injury compared to propofol.

Split liver transplantation: What’s unique?

The intraoperative management of split liver transplantation (SLT) has some unique features as compared to routine whole liver transplantations. Only the liver has this special ability to regenerate that confers benefits in survival and quality of life for two instead of one by splitting livers. Primary graft dysfunction may result from small for size syndrome. Graft weight to recipient body weight ratio is significant for both trisegmental and hemiliver grafts. Intraoperative surgical techniques aim to reduce portal hyperperfusion and decrease venous portal pressure. Ischemic preconditioning can be instituted to protect against ischemic reperfusion injury which impacts graft regeneration. Advancement of the technique of SLT is essential as use of split cadaveric grafts expands the donor pool and potentially has an excellent future.

Ischemia–reperfusion injury in patients with fatty liver and the clinical impact of steatotic liver on hepatic surgery

Hepatic steatosis is one of the most common hepatic disorders in developed countries. The epidemic of obesity in developed countries has increased with its attendant complications, including metabolic syndrome and non-alcoholic fatty liver disease. Steatotic livers are particularly vulnerable to ischemia/reperfusion injury, resulting in an increased risk of postoperative morbidity and mortality after liver surgery, including liver transplantation. There is growing understanding of the molecular and cellular mechanisms and therapeutic approaches for treating ischemia/reperfusion injury in patients with steatotic livers. This review discusses the mechanisms underlying the susceptibility of steatotic livers to ischemia/reperfusion injuries, such as mitochondrial dysfunction and signal transduction alterations, and summarizes the clinical impact of steatotic livers in the setting of hepatic resection and liver transplantation. This review also describes potential therapeutic approaches, such as ischemic and pharmacological preconditioning, to prevent ischemia/reperfusion injury in patients with steatotic livers. Other approaches, including machine perfusion, are also under clinical investigation; however, many pharmacological approaches developed through basic research are not yet suitable for clinical application.

Sevoflurane

Sevoflurane has been available for clinical practice for about 20 years. Nowadays, its pharmacodynamic and pharmacokinetic properties together with its absence of major adverse side effects on the different organ systems have made this drug accepted worldwide as a safe and reliable anesthetic agent for clinical practice in various settings.

Late Post-Conditioning with Sevoflurane after Cardiac Surgery--Are Surrogate Markers Associated with Clinical Outcome?

Introduction

In a recent randomized controlled trial our group has demonstrated in 102 patients that late post-conditioning with sevoflurane performed in the intensive care unit after surgery involving extracorporeal circulation reduced damage to cardiomyocytes exposed to ischemia reperfusion injury. On the first post-operative day the sevoflurane patients presented with lower troponin T values when compared with those undergoing propofol sedation. In order to assess possible clinical relevant long-term implications in patients enrolled in this study, we performed the current retrospective analysis focusing on cardiac and non-cardiac events during the first 6 months after surgery.

Methods

All patients who had successfully completed the late post-conditioning trial were included into this follow-up. Our primary and secondary endpoints were the proportion of patients experiencing cardiac and non-cardiac events, respectively. Additionally, we were interested in assessing therapeutic interventions such as initiation or change of drug therapy, interventional treatment or surgery.

Results

Of 102 patients analyzed in the primary study 94 could be included in this follow-up. In the sevoflurane group (with 41 patients) 16 (39%) experienced one or several cardiac events within 6 months after cardiac surgery, in the propofol group (with 53 patients) 19 (36%, p=0.75). Four patients (9%) with sevoflurane vs. 7 (13%) with propofol sedation had non-cardiac events (p=0.61). While a similar percentage of patients suffered from cardiac and/or non-cardiac events, only 12 patients in the sevoflurane group compared to 20 propofol patients needed a therapeutic intervention (OR: 0.24, 95% CI: 0.04-1.43, p=0.12). A similar result was found for hospital admissions: 2 patients in the sevoflurane group had to be re-admitted to the hospital compared to 8 in the propofol group (OR 0.23, 95% CI: 0.04-1.29, p=0.10).

Conclusions

Sevoflurane does not seem to provide protection with regard to the occurrence of cardiac and non-cardiac events in the 6-month period following cardiac surgery with the use of extracorporeal circulation. However, there was a clear trend towards fewer interventions (less need for treatment, fewer hospital admissions) associated with sevoflurane post-conditioning in patients experiencing any event. Such results might encourage launching large multicenter post-conditioning trials with clinical outcome defined as primary endpoint.

Insight into the beneficial immunomodulatory mechanism of the sevoflurane metabolite hexafluoro-2-propanol in a rat model of endotoxaemia

Volatile anaesthetics such as sevoflurane attenuate inflammatory processes, thereby impacting patient outcome significantly. Their inhalative administration is, however, strictly limited to controlled environments such as operating theatres, and thus an intravenously injectable immunomodulatory drug would offer distinct advantages. As protective effects of volatile anaesthetics have been associated with the presence of trifluorinated carbon groups in their basic structure, in this study we investigated the water-soluble sevoflurane metabolite hexafluoro-2-propanol (HFIP) as a potential immunomodulatory drug in a rat model of endotoxic shock. Male Wistar rats were subjected to intravenous lipopolysaccharide (LPS) and thereafter were treated with HFIP. Plasma and tissue inflammatory mediators, neutrophil invasion, tissue damage and haemodynamic stability were the dedicated end-points. In an endotoxin-induced endothelial cell injury model, underlying mechanisms were elucidated using gene expression and gene reporter analyses. HFIP reduced the systemic inflammatory response significantly and decreased endotoxin-induced tissue damage. Additionally, the LPS-provoked drop in blood pressure of animals was resolved by HFIP treatment. Pathway analysis revealed that the observed attenuation of the inflammatory process was associated with reduced nuclear factor kappa B (NF-κΒ) activation and suppression of its dependent transcripts. Taken together, intravenous administration of HFIP exerts promising immunomodulatory effects in endotoxaemic rats. The possibility of intravenous administration would overcome limitations of volatile anaesthetics, and thus HFIP might therefore represent an interesting future drug candidate for states of severe inflammation.

Identical MicroRNAs Regulate Liver Protection during Anaesthetic and Ischemic Preconditioning in Rats: An animal study

Anaesthetic preconditioning (APC) and ischemic preconditioning (IPC) ameliorate liver ischemia-reperfusion (I/R) injury and are important for regulating hepatic I/R injury. MicroRNAs (miRNAs) are short, noncoding RNA molecules of 21-23 nucleotides in length, and are currently under intensive investigation regarding their ability to regulate gene expression in a wide range of species. miRNA activity is involved in controlling a wide range of biological functions and processes. We evaluated whether APC and IPC are mediated by the same miRNAs by performing comprehensive miRNA screening experiments in a rat model of hepatic I/R injury. Twenty-one rats were randomly divided into three groups (n = 7/group): control (mock preconditioning), APC, and IPC. Control rats were subjected to 60 min of hepatic ischemia followed by 4 h of reperfusion, whereas the APC and IPC groups were preconditioned with 2% sevoflurane and hepatic ischemia for 10 min prior to ischemia-reperfusion, respectively. Liver samples were collected to measure miRNA levels after 3 h of reperfusion, and gene networks and canonical pathways were identified using Ingenuity Pathway Analysis (IPA). Blood samples were collected to measure the levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT). Although haemodynamic parameters did not vary among the groups, AST and ALT levels were significantly higher in the control group than in the APC and IPC groups. Comprehensive miRNA screening experiments revealed that most miRNAs altered in the APC group were common to those in the IPC group. IPA identified five miRNAs related to the Akt-glycogen synthase kinase-3β (GSK-3β)-cyclin D1 pathway that were significantly affected by both preconditioning strategies. The application of either APC or IPC to ameliorate hepatic I/R injury results in expression of several common miRNAs that are related to the Akt-GSK-cyclin D1 pathway.

Does inchinkoto, a herbal medicine, have hepatoprotective effects in major hepatectomy? A prospective randomized study

OBJECTIVES

This randomized clinical trial was designed to investigate whether inchinkoto has a hepatoprotective effect on postoperative outcome after major hepatectomy.

METHODS

Sixty-one patients scheduled for major hepatectomy were randomly assigned to one of two groups in which preoperative inchinkoto was (inchinkoto group, n = 30) or was not (non-inchinkoto group, n = 31) administered. Inchinkoto was administered for at least 7 days before surgery. The primary endpoint was the incidence of post-hepatectomy liver damage. The expression of nuclear factor E2-related factor 2 (Nrf2) and other oxygen stress-related markers in the liver were also determined.

RESULTS

There was no significant difference in clinical characteristics between the inchinkoto and non-inchinkoto groups. Serum levels in liver function tests and incidences of post-hepatectomy liver failure did not differ significantly between the two groups. However, there was a significantly higher induction of antioxidant factors in the liver, such as Nrf2 protein and heme oxygenase-1 mRNA, after hepatectomy in the inchinkoto group than in the non-inchinkoto group.

CONCLUSIONS

The preoperative administration of inchinkoto did not have a significant impact on the overall outcome of major hepatectomy. However, inchinkoto induced the expression of Nrf2 during hepatectomy and may have exerted an antioxidative effect on the liver.

Hepatic cytoprotective effect of ischemic and anesthetic preconditioning before liver resection when using intermittent vascular inflow occlusion: a randomized clinical trial

BACKGROUND

Ischemic preconditioning (IPC) and anesthetic preconditioning (APC) have been reported to attenuate ischemia-reperfusion (IR) injury after liver resection under continuous inflow occlusion. This study evaluates whether these strategies enhance hepatic protection of remnant liver against IR after liver resection with intermittent clamping (INT).

METHODS

A total of 106 patients without underlying liver disease and submitted to liver resection using INT were randomized into 3 groups: IPC (10 minutes of inflow occlusion followed by 10 minutes of reperfusion before liver transection), APC (sevoflurane administration for 20 minutes before liver transection), and INT (no preconditioning). Patients were also stratified according to the extent of the hepatectomy. Cytoprotection was evaluated by comparing hepatocyte and endothelial dysfunction markers, apoptosis, histologic lesions, and postoperative outcome.

RESULTS

No differences were observed in preoperative chemotherapy and steatosis, total warm ischemia time, operative time, or blood loss. Kinetics of transaminases (aspartate aminotransferase, P = .137; alanine aminotransferase, P = .616), bilirubin (P = .980), and hyaluronic acid increase (P = .514) revealed no differences. Significant apoptosis was present in 40% of patients, mild-to-moderate leukocyte infiltration and steatosis in 45% and 55%, respectively, and mild sinusoidal congestion in 65%, with a similar distribution in the 3 groups. When patients were stratified by major versus minor resections, no differences were observed in any of the variables studied. Postoperative clinical outcomes were also similar.

CONCLUSION

These results suggest that these protocols of IPC and APC used in this study do not provide better cytoprotection from IR when INT is used.

Volatile anesthetic sevoflurane ameliorates endotoxin-induced acute lung injury via microRNA modulation in rats

Volatile anesthetics have a lung protective effect in acute lung injury (ALI). Our previous study showed sevoflurane affects the expression of microRNA (miRNA) that control various physiological systems by regulating messenger RNA (mRNA) expression. However, the association between the anti-inflammatory effect of sevoflurane and miRNAs modulation remains unknown. The aim of the present study was to investigate the effect of sevoflurane and the expression of miRNAs in an endotoxin-induced ALI model in rats. Wistar rats were randomly assigned to three groups [lipopolysaccharide (LPS), LPS-sevoflurane and control; n=8/group]. All the rats were mechanically ventilated and intravenously-administered LPS (saline as control). Two hours post-injury, general anaesthesia was performed for 4 h with 2% sevoflurane (LPS-sevoflurane). The LPS and the control groups did not receive anaesthesia. The severity of ALI was evaluated by partial pressure of oxygen/fraction of inspired oxygen and the mRNA expression of inflammatory cytokine. The miRNA expression in lung tissue was analyzed by a reverse transcription-quantitative polymerase chain reaction. LPS caused ALI, evidenced by the impairment of pulmonary function and increased mRNA levels of tumor necrosis factor-α, interleukin-6 and nuclear factor-κB. Sevoflurane improved pulmonary function and inhibited the increased mRNAs. Of the 219 miRNAs detected, 15 and nine miRNAs were significantly changed in the LPS and LPS-sevoflurane group, respectively. In the LPS-sevoflurane group, the expression of several miRNAs that regulate inflammation was significantly changed compared to the LPS group. In conclusion, the present data showed that sevoflurane influences the expression of the miRNAs that regulate inflammation. This result suggests that the changes in miRNA expression are involved in the lung protective mechanisms of volatile anesthetics.

Challenges to liver transplantation and strategies to improve outcomes

Liver transplantation (LT) is a highly successful treatment for many patients with nonmalignant and malignant liver diseases. However, there is a worldwide shortage of available organs; many patients deteriorate or die while on waiting lists. We review the important clinical challenges to LT and the best use of the scarce organs. We focus on changes in indications for LT and discuss scoring systems to best match donors with recipients and optimize outcomes, particularly for the sickest patients. We also cover controversial guidelines for the use of LT in patients with hepatocellular carcinoma and cholangiocarcinoma. Strategies to increase the number of functional donor organs involve techniques to perfuse the organs before implantation. Partial LT (living donor and split liver transplantation) techniques might help to overcome organ shortages, and we discuss small-for-size syndrome. Many new developments could increase the success of this procedure, which is already one of the major achievements in medicine during the second part of the 20th century.

Effect of remote ischemic postconditioning on patients undergoing living donor liver transplantation

The aim of this study was to evaluate the protective effect of remote ischemic postconditioning (RIPostC) on graft function and acute kidney injury (AKI) after living donor liver transplantation (LT). Recipients undergoing elective living donor LT were randomly assigned to either the RIPostC group or the control group. Immediately after reperfusion, 4 cycles of ischemia and reperfusion lasting for 5 minutes each were performed on 1 upper limb in the RIPostC group. Graft function was assessed through evaluations of the serum levels of total bilirubin and liver enzymes and the prothrombin time for 28 days after surgery. The incidence of AKI, as defined by the Risk, Injury, Failure, Loss, and End-Stage Kidney Disease classification, was evaluated within 28 days of the operation. In addition, the incidences of graft dysfunction, acute cellular rejection, and major complications; the 1-, 3-, and 6-month mortality rates; the length of stay in the intensive care unit; and the length of hospital stay were also investigated. In all, 78 patients were enrolled in the analysis (n = 39 in each group). No differences in graft function or clinical outcomes were observed between the groups. The incidences of postoperative AKI were 38% (n = 15) in the RIPostC group and 72% (n = 28) in the control group (P = 0.006). Despite no improvements in postoperative graft function, RIPostC decreased the incidence of postoperative AKI after living donor LT in this study. However, no other clinical benefits with respect to the complication rate, length of hospital stay, or short-term mortality rate were observed. Thus, further studies will be needed to evaluate the clinical efficacy of RIPostC in LT fully.

End of life care in the operating room for non-heart-beating donors: organization at the University Hospital of Liège

Non-heart-beating (NHB) organ donation has become an alternative source to increase organ supply for transplantation. A NHB donation program was implemented in our institution in 2002. As in many institutions the end of life care of the NHB donor (NHBD) is terminated in the operating room (OR) to reduce warm ischemia time. Herein we have described the organization of end of life care for these patients in our institution, including the problems addressed, the solution proposed, and the remaining issues. Emphasis is given to our protocol elaborated with the different contributors of the chain of the NHB donation program. This protocol specifies the information mandatory in the medical records, the end of life care procedure, the determination of death, and the issue of organ preservation measures before NHBD death. The persisting malaise associated with NHB donation reported by OR nurses is finally documented using an anonymous questionnaire.

The role of hepatic ischemia-reperfusion injury and liver parenchymal quality on cancer recurrence

Hepatic ischemia/reperfusion (I/R) injury is a common clinical challenge. Despite accumulating evidence regarding its mechanisms and potential therapeutic approaches, hepatic I/R is still a leading cause of organ dysfunction, morbidity, and resource utilization, especially in those patients with underlying parenchymal abnormalities. In the oncological setting, there are growing concerns regarding the deleterious impact of I/R injury on the risk of post-surgical tumor recurrence. This review aims at giving the last updates regarding the role of hepatic I/R and liver parenchymal quality injury in the setting of oncological liver surgery, using a "bench-to-bedside" approach. Relevant medical literature was identified by searching PubMed and hand scanning of the reference lists of articles considered for inclusion. Numerous preclinical models have depicted the impact of I/R injury and hepatic parenchymal quality (steatosis, age) on increased cancer growth in the injured liver. Putative pathophysiological mechanisms linking I/R injury and liver cancer recurrence include an increased implantation of circulating cancer cells in the ischemic liver and the upregulation of proliferation and angiogenic factors following the ischemic insult. Although limited, there is growing clinical evidence that I/R injury and liver quality are associated with the risk of post-surgical cancer recurrence. In conclusion, on top of its harmful early impact on organ function, I/R injury is linked to increased tumor growth. Therapeutic strategies tackling I/R injury could not only improve post-surgical organ function, but also allow a reduction in the risk of cancer recurrence.

Inhibition of N-myc Downstream–regulated Gene-2 Is Involved in an Astrocyte-specific Neuroprotection Induced by Sevoflurane Preconditioning

Background:

Mechanism of sevoflurane preconditioning–induced cerebral ischemic tolerance is unclear. This study investigates the role of N-myc downstream–regulated gene-2 (NDRG2) in the neuroprotection of sevoflurane preconditioning in ischemic model both in vivo and in vitro.

Methods:

At 2 h after sevoflurane (2%) preconditioning for 1 h, rats were subjected to middle cerebral artery occlusion for 120 min. Neurobehavioral scores (n = 10), infarct volumes (n = 10), cellular apoptosis (n = 6), and NDRG2 expression (n = 6) were determined at 24 h after reperfusion. In vitro, cultural astrocytes were exposed to oxygen–glucose deprivation for 4 h. Cellular viability, cytotoxicity, apoptosis, and NDRG2 expression (n = 6) were evaluated in the presence or absence of NDRG2-specific small interfering RNA or NDRG2 overexpression plasmid.

Results:

Sevoflurane preconditioning decreased apoptosis (terminal deoxynucleotidyl transferase–mediated 2’-deoxyuridine 5’-triphosphate nick-end labeling–positive cells reduced to 31.2 ± 5.3% and cleaved Caspase-3 reduced to 1.42 ± 0.21 fold) and inhibited NDRG2 expression (1.28 ± 0.15 fold) and nuclear translocation (2.21 ± 0.29 fold) in ischemic penumbra. Similar effects were observed in cultural astrocytes exposed to oxygen–glucose deprivation. NDRG2 knockdown by small interfering RNA attenuated oxygen–glucose deprivation–induced injury (cell viability increased to 80.5 ± 4.1%; lactate dehydrogenase release reduced to 30.5 ± 4.0%) and cellular apoptosis (cleaved Caspase-3 reduced to 1.55 ± 0.21 fold; terminal deoxynucleotidyl transferase–mediated 2’-deoxyuridine 5’-triphosphate nick-end labeling–positive cells reduced to 18.2 ± 4.3%), whereas NDRG2 overexpression reversed the protective effects of sevoflurane preconditioning. All the data are presented as mean ± SD.

Conclusion:

Sevoflurane preconditioning inhibits NDRG2 up-regulation and nuclear translocation in astrocytes to induce cerebral ischemic tolerance via antiapoptosis, which represents one new mechanism of sevoflurane preconditioning and provides a novel target for neuroprotection.

Advances in the management of the explanted donor liver

Liver transplantation is the best therapy in end-stage liver disease. Donor organ shortage and efforts to expand the donor organ pool are permanent issues given that advances in perioperative management and immunosuppressive therapy have brought the procedure into widespread clinical use. The management of organ procurement, including donor preconditioning and adequate organ storage, has a key role in transplantation. However, the organ procurement process can differ substantially between transplant centres, depending on local and national preferences. Advances in the field have come from experimental and clinical research on dynamic storage systems, such as machine perfusion devices, as an alternative to static cold storage. Determination of the clinical significance of these new systems is a topic worthy of future investigations.

Volatile anaesthetics reduce neutrophil inflammatory response by interfering with CXC receptor-2 signalling

BACKGROUND

Growing evidence suggests a protective effect of volatile anaesthetics in ischaemia-reperfusion (I/R)-injury, and the accumulation of neutrophils is a crucial event. Pro-inflammatory cytokines carrying the C-X-C-motif including interleukin-8 (IL-8) and CXC-ligand 1 (CXCL1) activate CXC receptor-1 (CXCR1; stimulated by IL-8), CXC receptor-2 (CXCR2; stimulated by IL-8 and CXCL1), or both to induce CD11b-dependent neutrophil transmigration. Inhibition of CXCR1, CXCR2, or both reduces I/R-injury by preventing neutrophil accumulation. We hypothesized that interference with CXCR1/CXCR2 signalling contributes to the well-established beneficial effect of volatile anaesthetics in I/R-injury.

METHODS

Isolated human neutrophils were stimulated with IL-8 or CXCL1 and exposed to volatile anaesthetics (sevoflurane/desflurane). Neutrophil migration was assessed using an adapted Boyden chamber. Expression of CD11b, CXCR1, and CXCR2 was measured by flow cytometry. Blocking antibodies against CXCR1/CXCR2/CD11b and phorbol myristate acetate were used to investigate specific pathways.

RESULTS

Volatile anaesthetics reduced CD11b-dependent neutrophil transmigration induced by IL-8 by >30% and CD11b expression by 18 and 27% with sevoflurane/desflurane, respectively. This effect was independent of CXCR1/CXCR2 expression and CXCR1/CXCR2 endocytosis. Inhibition of CXCR1 signalling did not affect downregulation of CD11b with volatile anaesthetics. Blocking of CXCR2-signalling neutralized effects by volatile anaesthetics on CD11b expression. Specific stimulation of CXCR2 with CXCL1 was sufficient to induce upregulation of CD11b, which was impaired with volatile anaesthetics. No effect of volatile anaesthetics was observed with direct stimulation of protein kinase C located downstream of CXCR1/CXCR2.

CONCLUSION

Volatile anaesthetics attenuate neutrophil inflammatory responses elicited by CXC cytokines through interference with CXCR2 signalling. This might contribute to the beneficial effect of volatile anaesthetics in I/R-injury.

Comparison of minimal access and traditional anterior spinal surgery in managing infectious spondylitis: a minimum 2-year follow-up

BACKGROUND CONTEXT

Traditional anterior spinal surgery (TASS) for the thoracolumbar spine is associated with significant morbidities. To avoid excessive tissue damage, minimal access spinal surgery (MASS) has been developed to treat a variety of anterior spinal disorders at the authors' institution. No previous reports comparing the outcomes of MASS and TASS for the treatment of infectious spondylitis were noted in the literature, to our knowledge.

PURPOSE

The aim of this study was to investigate the outcomes of MASS in managing infectious spondylitis and compare the results to TASS with a minimum follow-up of 2 years.

STUDY DESIGN

A retrospective comparative cohort study in a single center.

PATIENT SAMPLE

Forty patients with thoracic or lumbar infectious spondylitis who underwent anterior spinal surgery were enrolled.

OUTCOME MEASURES

Perioperative data including operative time, estimated blood loss, packed red blood cell transfusion, postoperative tube drainage, need for intensive care, and length of hospital stay. Postoperative complications were classified according to the Clavien-Dindo system. Fusion grade was assessed by plain radiographs on the basis of Burkus criteria.

METHODS

Between January 2002 and June 2010, all enrolled patients were collected via the Spine Operation Registry of the authors' institution. There were 23 MASS patients and 17 TASS patients. The average follow-up was 4.2 years (range, 2-9 years).

RESULTS

The mean estimated blood loss in MASS and TASS groups was 521.7 versus 979.4 mL (p=.007), intraoperative transfusion of packed red blood cells was 0.9 versus 2.7 units (p=.019), the amount of postoperative tube drainage was 235.2 versus 454.3 mL (p=.005), the number of patients requiring postoperative intensive care was 2 versus 7 (p=.023), and length of hospital stay was 15.4 versus 22.9, respectively (p=.043). The overall complication rate in the MASS group was 17% and 59% in the TASS group (p=.007). No major complications occurred in the MASS group, whereas four occurred in the TASS group (p=.026). Bone graft union was achieved in 38 of 39 survival patients (97%), with no difference between the groups. One patient in TASS had a pseudarthrosis and needed a posterior instrumented fusion.

CONCLUSIONS

Minimal access spinal surgery has been suggested to be an effective and safe technique in treating thoracic and lumbar infectious spondylitis. Minimal access spinal surgery did not need endoscopic equipments or complex surgical instruments. Furthermore, in comparison to TASS, MASS resulted in a reduced blood transfusion amount, decreased intensive care unit stay, reduced overall length of stay, and reduced surgical complication rate. Nevertheless, the risks may be increased in performing MASS on patients with multilevel involvement, which could be associated with high vascularity, alternated vascular anatomy, increased soft-tissue edema, and adhesion.

Solutions to shortage of liver grafts for transplantation

Increasing the donor supply

Anesthesia, microcirculation, and wound repair in aging

Age-related changes in skin contribute to impaired wound healing after surgical procedures. Changes in skin with age include decline in thickness and composition, a decrease in the number of most cell types, and diminished microcirculation. The microcirculation provides tissue perfusion, fluid homeostasis, and delivery of oxygen and other nutrients. It also controls temperature and the inflammatory response. Surgical incisions cause further disruption of the microvasculature of aged skin. Perioperative management can be modified to minimize insults to aged tissues. Judicious use of fluids, maintenance of normal body temperature, pain control, and increased tissue oxygen tension are examples of adjustable variables that support the microcirculation. Anesthetic agents influence the microcirculation of a combination of effects on cardiac output, arterial pressure, and local microvascular changes. The authors examined the role of anesthetic management in optimizing the microcirculation and potentially improving postoperative wound repair in older persons.