Effect of the opioid remifentanil on cellular immune response in the rat

The Impact of Different Anesthetics on the Distribution and Cytotoxic Function of NK Cell Subpopulations: An In Vitro Study

Only some subpopulations of natural killer (NK) cells have cytotoxic functionality, and the effects of anesthetics on these subpopulations are unknown. This study aimed to evaluate the in vitro effects of various anesthetics, both alone and in combination, on the distribution and cytotoxic function of NK cells and their subpopulations. Peripheral blood mononuclear cells (PBMCs) from eight healthy volunteers were treated for 4 h in vitro with dexmedetomidine, remifentanil, lidocaine, propofol, sevoflurane, and combinations in clinically relevant concentrations or left untreated. Flow cytometry was used to quantify the percentage of sampled NK cells and evaluate their distribution (CD56brightCD16neg, CD56brightCD16dim, CD56dimCD16neg, CD56dimCD16bright, and CD56negCD16bright) and cytotoxicity (Granzyme B (GrzB) and perforin) of NK cell subpopulations. Although the percentage of total NK cells did not change following exposure to anesthesia, the most important cytotoxic subpopulation (CD56dimCD16bright NK cells) decreased after exposure to both propofol (-3.58%, p = 0.045) and sevoflurane (-16.10%, p = 0.008) alone, and most combinations, especially in combination with lidocaine (propofol with lidocaine (-9.66%, p = 0.002) and sevoflurane with lidocaine (-21.90%, p < 0.001)). Dexmedetomidine and remifentanil had no effect on CD56dimCD16bright NK cells. Furthermore, no anesthetic regimen or combination altered the expression of GrzB and perforin in NK cells or NK cell subpopulations. In short, propofol and sevoflurane suppressed the highly cytotoxic phenotype (CD56dimCD16bright) of NK cells, with those exposed to sevoflurane combinations showing greater reductions. Immunosuppression was intensified with the inclusion of lidocaine in the anesthetic regimen.

A study on construction of a prognosis model for liver cancer based on analgesic targets and screening therapeutic drugs

BACKGROUND

Liver cancer is one of the most malignant liver diseases in the world, and the 5-year survival rate of such patients is low. Analgesics are often used to cure pain prevalent in liver cancer. The expression changes and clinical significance of the analgesic targets (ATs) in liver cancer have not been deeply understood.

OBJECTIVE

The purpose of this study is to clarify the expression pattern of ATs gene in liver cancer and its clinical significance. Through the comprehensive analysis of transcriptome data and clinical parameters, the prognosis model related to ATs gene is established, and the drug information sensitive to ATs is mined.

METHODS

The study primarily utilized transcriptomic data and clinical information from liver cancer patients sourced from The Cancer Genome Atlas (TCGA) database. These data were employed to analyze the expression of ATs, conduct survival analysis, gene set variation analysis (GSVA), immune cell infiltration analysis, establish a prognostic model, and perform other bioinformatic analyses. Additionally, data from liver cancer patients in the International Cancer Genome Consortium (ICGC) were utilized to validate the accuracy of the model. Furthermore, the impact of analgesics on key genes in the prognostic model was assessed using data from the Comparative Toxicogenomics Database (CTD).

RESULTS

The study investigated the differential expression of 58 ATs genes in liver cancer compared to normal tissues. Patients were stratified based on ATs expression, revealing varied survival outcomes. Functional enrichment analysis highlighted distinctions in spindle organization, centrosome, and spindle microtubule functions. Prognostic modeling identified low TP53 expression as protective, while elevated CCNA2, NEU1, and HTR2C levels posed risks. Commonly used analgesics, including acetaminophen and others, were found to influence the expression of these genes. These findings provide insights into potential therapeutic strategies for liver cancer and shed light on the molecular mechanisms underlying its progression.

CONCLUSIONS

The collective analysis of gene signatures associated with ATs suggests their potential as prognostic predictors in hepatocellular carcinoma patients. These findings not only offer insights into cancer therapy but also provide novel avenues for the development of indications for analgesics.

Lost in Translation: Failure of Preclinical Studies to Accurately Predict the Effect of Regional Analgesia on Cancer Recurrence

The major goal of translational research is to evaluate the efficacy and effectiveness of treatments and interventions that have emerged from exhaustive preclinical evidence. In 2007, a major clinical trial was started to investigate the impact of paravertebral analgesia on breast cancer recurrence. The trial was based on preclinical evidence demonstrating that spinal anesthesia suppressed metastatic dissemination by inhibiting surgical stress, boosting the immunological response, avoiding volatile anesthetics, and reducing opioid use. However, that trial and three more recent randomized trials with a total of 4,770 patients demonstrate that regional analgesia does not improve survival outcomes after breast, lung, and abdominal cancers. An obvious question is why there was an almost complete disconnect between the copious preclinical investigations suggesting benefit and robust clinical trials showing no benefit? The answer is complex but may result from preclinical research being mechanistically driven and based on reductionist models. Both basic scientists and clinical investigators underestimated the limitations of various preclinical models, leading to the apparently incorrect hypothesis that regional anesthesia reduces cancer recurrence. This article reviews factors that contributed to the discordance between the laboratory science, suggesting that regional analgesia might reduce cancer recurrence and clinical trials showing that it does not-and what can be learned from the disconnect.

Effect of sevoflurane-remifentanil and propofol-remifentanil anesthesia on glycocalyx shedding during deep inferior epigastric perforator flap breast reconstruction: a prospective randomized, controlled trial

BACKGROUND

The endothelial glycocalyx (EG) is an important structure that regulates vascular homeostasis. Deep inferior epigastric perforator (DIEP) flap is expected to cause substantial EG breakdown owing to the long procedural duration and ischemia- reperfusion injury. This prospective, randomized, controlled study aimed to compare syndecan-1 levels during sevoflurane-remifentanil and propofol-remifentanil anesthesia in patients who underwent DIEP flap breast reconstruction.

METHODS

Fifty-one patients were randomized to either sevoflurane (n = 26) or propofol (n = 25) groups. Anesthesia was maintained with remifentanil in combination with either sevoflurane or propofol. The primary endpoint was the concentration of serum syndecan-1 measured at 1 h after surgery.

RESULTS

Fifty patients (98.0%) completed the study. Patients in the propofol group had significantly lower levels of syndecan-1 than patients in the sevoflurane group at 1 h after operation (23.8 ± 1.6 vs. 30.9 ± 1.7 ng/ml, respectively; Bonferroni corrected P = 0.012). There were no significant differences between groups in postoperative complications. The postoperative hospital stay was 8.4 ± 2.5 days in the sevoflurane group and 7.4 ± 1.0 days in the propofol group (P = 0.077).

CONCLUSIONS

Propofol-remifentanil anesthesia resulted in lesser increases in syndecan-1 levels compared to increases with sevoflurane-remifentanil anesthesia in patients who underwent DIEP flap reconstruction. Our results suggest that propofol-remifentanil anesthesia shows protective effects against EG damage during DIEP flap breast reconstruction in contrast to sevoflurane-remifentanil anesthesia.

Anesthesia and cancer recurrence: an overview

Several perioperative factors are responsible for the dysregulation or suppression of the immune system with a possible impact on cancer cell growth and the development of new metastasis. These factors have the potential to directly suppress the immune system and activate hypothalamic-pituitary-adrenal axis and the sympathetic nervous system with a consequent further immunosuppressive effect.Anesthetics and analgesics used during the perioperative period may modulate the innate and adaptive immune system, inflammatory system, and angiogenesis, with a possible impact on cancer recurrence and long-term outcome. Even if the current data are controversial and contrasting, it is crucial to increase awareness about this topic among healthcare professionals for a future better and conscious choice of anesthetic techniques.In this article, we aimed to provide an overview regarding the relationship between anesthesia and cancer recurrence. We reviewed the effects of surgery, perioperative factors, and anesthetic agents on tumor cell survival and tumor recurrence.

Dose of intra-operative opioids has no impact on recurrence or survival in primary liver cancer

BACKGROUND

Intra-operative use of opioid analgesics might have an impact on cancer recurrence and survival after surgery. The objective of this study was to investigate the association between the intra-operative fentanyl equivalents and survival outcomes in patients with primary liver cancer after receiving hepatectomy.

METHODS

This was a retrospective single-center cohort study, and clinical data of 700 patients with primary liver cancer who underwent hepatectomy in Harbin Medical University Cancer Hospital from September 2013 to August 2018 were reviewed. After propensity matching, 376 patients were included. Patients were divided into high-dose and low-dose groups according to the median intra-operative fentanyl equivalents (1.500 mg). Kaplan Meier curve and Cox proportional hazards regression model were used.

RESULTS

Results of univariable analysis showed there were no significant differences in recurrence-free survival (RFS) (p = 0.136) and overall survival (OS) (p = 0.444) between high-dose fentanyl equivalents and low-dose fentanyl equivalents group. The multivariable Cox regression analysis found that the dose of intra-operative fentanyl equivalents was not associated with RFS (HR: 1.119, 95%CI: 0.851-1.472, p = 0.422) or OS (HR: 0.939, 95%CI: 0.668-1.319, p = 0.715).

CONCLUSIONS

The amounts of intra-operative fentanyl equivalents had no impact on recurrence-free or overall survival in patients with primary liver cancer after curative hepatectomy.

Current Status and Prospects of Anesthesia and Breast Cancer: Does Anesthetic Technique Affect Recurrence and Survival Rates in Breast Cancer Surgery?

The relationship between the anesthetic technique and cancer recurrence has not yet been clarified in cancer surgery. Surgical stress and inhalation anesthesia suppress cell-mediated immunity (CMI), whereas intravenous (IV) anesthesia with propofol and regional anesthesia (RA) are known to be protective for CMI. Surgical stress, general anesthesia (GA) with inhalation anesthesia and opioids contribute to perioperative immunosuppression and may increase cancer recurrence and decrease survival. Surgical stress and GA activate the hypothalamic-pituitary-adrenal axis and release neuroendocrine mediators such as cortisol, catecholamines, and prostaglandin E₂, which may reduce host defense immunity and promote distant metastasis. On the other hand, IV anesthesia with propofol and RA with paravertebral block or epidural anesthesia can weaken surgical stress and GA-induced immunosuppression and protect the host defense immunity. IV anesthesia with propofol and RA or in combination with GA may reduce cancer recurrence and improve patient survival compared to GA alone. We review the current status of the relationship between anesthesia and breast cancer recurrence using retrospective and prospective studies conducted with animal models and clinical samples, and discuss the future prospects for reducing breast cancer recurrence and improving survival rates in breast cancer surgery.

Effects of Perioperative Epidural Analgesia on Cancer Recurrence and Survival

Surgical resection is the main curative avenue for various cancers. Unfortunately, cancer recurrence following surgery is commonly seen, and typically results in refractory disease and death. Currently, there is no consensus whether perioperative epidural analgesia (EA), including intraoperative and postoperative epidural analgesia, is beneficial or harmful on cancer recurrence and survival. Although controversial, mounting evidence from both clinical and animal studies have reported perioperative EA can improve cancer recurrence and survival via many aspects, including modulating the immune/inflammation response and reducing the use of anesthetic agents like inhalation anesthetics and opioids, which are independent risk factors for cancer recurrence. However, these results depend on the cancer types, cancer staging, patients age, opioids use, and the duration of follow-up. This review will summarize the effects of perioperative EA on the oncological outcomes of patients after cancer surgery.

Breast Cancer and Anaesthesia: Genetic Influence

Breast cancer is the leading cause of mortality in women. It is a heterogeneous disease with a high degree of inter-subject variability even in patients with the same type of tumor, with individualized medicine having acquired significant relevance in this field. The clinical and morphological heterogeneity of the different types of breast tumors has led to a diversity of staging and classification systems. Thus, these tumors show wide variability in genetic expression and prognostic biomarkers. Surgical treatment is essential in the management of these patients. However, the perioperative period has been found to significantly influence survival and cancer recurrence. There is growing interest in the pro-tumoral effect of different anaesthetic and analgesic agents used intraoperatively and their relationship with metastatic progression. There is cumulative evidence of the influence of anaesthetic techniques on the physiopathological mechanisms of survival and growth of the residual neoplastic cells released during surgery. Prospective randomized clinical trials are needed to obtain quality evidence on the relationship between cancer and anaesthesia. This document summarizes the evidence currently available about the effects of the anaesthetic agents and techniques used in primary cancer surgery and long-term oncologic outcomes, and the biomolecular mechanisms involved in their interaction.

The Effects of Anesthetics and Perioperative Medications on Immune Function: A Narrative Review

Preclinical and clinical studies have sought to better understand the effect of anesthetic agents, both volatile and intravenous, and perioperative adjuvant medications on immune function. The immune system has evolved to incorporate both innate and adaptive components, which are delicately interwoven and essential for host defense from pathogens and malignancy. This review summarizes the complex and nuanced relationship that exists between each anesthetic agent or perioperative adjuvant medication studied and innate and adaptive immune function with resultant clinical implications. The most commonly used anesthetic agents were chosen for review including volatile agents (sevoflurane, isoflurane, desflurane, and halothane), intravenous agents (propofol, ketamine, etomidate, and dexmedetomidine), and perioperative adjuvant medications (benzodiazepines, opioids, nonsteroidal anti-inflammatory drugs [NSAIDs], and local anesthetic agents). Patients who undergo surgery experience varying combinations of the aforementioned anesthetic agents and adjuncts, depending on the type of surgery and their comorbidities. Each has unique effects on immunity, which may be more or less ideal depending on the clinical situation. Further study is needed to better understand the clinical effects of these relationships so that patient-specific strategies can be developed to improve surgical outcomes.

A Critical Appraisal of the Effects of Anesthetics on Immune-system Modulation in Critically Ill Patients With COVID-19

Purpose

The aim of the present article was to briefly summarize current knowledge about the immunomodulatory effects of general anesthetics and the possible clinical effects of this immunomodulation in patients with COVID-19.

Methods

The PubMed, Scopus, and Google Scholar databases were comprehensively searched for relevant studies.

Findings

The novel coronavirus causes a wide spectrum of clinical manifestations, with a large absolute number of patients experiencing severe pneumonia and rapid progression to acute respiratory distress syndrome and multiple organ failure. In these patients, the equilibrium of the inflammatory response is a major determinant of survival. The impact of anesthetics on immune-system modulation may vary and includes both pro-inflammatory and anti-inflammatory effects.

Implications

Inhibition of the development of severe inflammation and/or the enhancement of inflammation resolution by anesthetics may limit organ damage and improve outcomes in patients with COVID-19.

Opioid-Induced Immunomodulation: Consequences for the Experimental Coxsackievirus B3-Induced Myocarditis Model

Simple Summary

Myocarditis is an inflammatory disorder of the heart mainly caused by viruses. To investigate viral myocarditis, the Coxsackievirus B3 (CVB3)-induced myocarditis model is the experimental model used since more than sixty years. In the pathogeneses of viral myocarditis, the subtle balance between pro-and anti-inflammatory immune responses is of great importance for disease manifestation. Parallel to the infection of the heart, experimental CVB3-induced myocarditis results in an infection of the pancreas, causing a severe burden for the challenged animals. In frame of animal welfare, application of analgesics is mandatory. So far, positive as well as negative effects of opioids on the immune system have been described. However, the impact of opioid application on the pathogenesis of experimental CVB3-induced myocarditis has not been investigated yet. Since examinations on disease pathways and new treatment options rely on established models to generate reproducible data, applicability of opioids in experimental CVB3-induced myocarditis needs to be carefully evaluated. For this purpose, we summarized published studies for 13 different opioids and discussed their potential impact on the CVB3-induced myocarditis model.

Abstract

Myocarditis is an inflammatory disorder of the heart predominantly caused by infectious agents. Since more than sixty years, the Coxsackievirus B3 (CVB3)-induced myocarditis mouse model is the experimental model used to investigate viral myocarditis. The pathogenesis of viral myocarditis is conceptually a multiphase process, initiated by the infection of cardiomyocytes, followed by activation of the immune system, and resulting in myocardial fibrosis and left ventricular dysfunction. In parallel to the direct infection of the heart, CVB3 replicates in lymphatic organs such as the pancreas. Due to infection of the pancreas, the model of experimental CVB3-induced myocarditis is estimated as a severe burden for the challenged animals. Application of analgesics in frame of the animal welfare act (European directive 2010/63/EU) is more and more becoming a matter of debate. For this purpose, we summarized published studies for 13 different opioids and discussed their potential impact on CVB3-induced myocarditis. In addition, with this summary we also want to provide guidance for researchers beyond the myocarditis field to estimate the impact of opioids on the immune system for their specific model. In the literature, both immunosuppressive as well as immune-activating effects of opioids have been described, but examinations in experimental CVB3-induced myocarditis have still not been reported so far. Based on the existing publications, administration of opioids in experimental CVB3-induced myocarditis might result in more severe disease progression, including higher mortality, or a less pronounced myocarditis model, failing to be used for the establishment of new treatment options. Taken together, the applicability of opioids in experimental CVB3-induced myocarditis and in inflammatory models in general needs to be carefully evaluated and further investigated.

Immunomodulation by ketamine as an adjunct to total intravenous anesthesia in patients undergoing minimally invasive radical prostatectomy: A randomized pilot trial

Post-surgery immunomodulation, including reduced natural killer cell cytotoxicity (NKCC), is recognized as a predictor of poor outcomes in patients following cancer surgery. The present study investigated direct immunomodulation via ketamine as an anesthetic adjuvant in patients undergoing cancer surgery. The present non-double blinded randomized trial was conducted at Hirosaki University Hospital with 60 patients who underwent minimally invasive robotic radical prostatectomy to minimize the immunomodulation due to surgical stress. Patients received total intravenous anesthesia using propofol and remifentanil, with ketamine as an anesthetic adjuvant (the ketamine group) or without ketamine (the control group). The primary outcome was the difference in NKCC between these groups. The secondary outcomes were the differences in neutrophil-lymphocyte ratio (NLR) and levels of interleukin (IL)-6, IL-1β, IL-10 and tumor necrosis factor-alpha (TNF-α). NKCC and cytokines were measured before anesthesia (baseline) and at 6 and 24 h after baseline measurements were recorded. NLR was determined on the last day before admission and at 48 h post-baseline. NKCC values were similar in each group at 6 h when compared with respective baseline results (baseline control, 36.9±15.6%; 6 h control, 38.3±13.4%; baseline ketamine, 36.1±17.0%; 6 h ketamine, 36.6±16.4%) but significantly decreased at 24 h (control, 26.5±12.2%; ketamine, 24.1±12.7%; P<0.001). There were no significant differences in NKCC between the ketamine and control groups (P=0.64) at any of the assessed time points. NLR, IL-1β, IL-10 and TNF-α levels were also similar between two groups. In contrast, IL-6 at 24 h was significantly lower in the ketamine group compared with the control group (mean difference, -7.3 pg ml^-1; 95% confidence interval, -14.4 to -0.2; P=0.04). Ketamine as an anesthetic adjuvant did not provide direct immunomodulation in patients who underwent cancer surgery.

Remifentanil attenuates cardiac dysfunction, lipid peroxidation and immune disorder in rats with isoproterenol-induced myocardial injury via JNK/NF-KB p65 inhibition

Background

Myocardial injury caused by myocardial ischemia (MI) is still a severe condition that can result in apoptosis, oxidative stress, and inflammation. Remifentanil is a selective, ultra-short-acting, µ-opioid receptor agonist opioid. It can improve sinusoidal heart rate patterns in the fetus, for bupivacaine-induced cardiotoxicity, and with lipopolysaccharide (LPS)-induced cardiomyocytes injuries. This study aimed to explore the cardioprotective effects of remifentanil in MI model rats.

Methods

Sprague Dawley (SD) rats were split into five groups at random, including a control group, Isop group, low-dose remifentanil treatment group (10 µg/kg), medium-dose remifentanil treatment group (20 µg/kg), and a high-dose remifentanil treatment group (40 µg/kg). The MI model was achieved by subcutaneously injecting rats with isoproterenol (85 mg/kg) for two consecutive days. With the expression of apoptotic molecules, myocardial systolic function index, inflammation, antioxidant enzymes, and the myocardial enzyme taken into account, the data was analyzed.

Results

After treatment with remifentanil, the left ventricular wall thickness (LVWT), left ventricular end-systolic volume (LVESV), left ventricular ejection fraction (LVEF), fraction shortening (FS), and heart rate (HR) were significantly increased in comparison with the Isop group. Creatine kinase-MB (CK-MB), Mb, and cTnl expressions were decreased. Meanwhile, the levels of cleaved caspase-3 and caspase-9 were decreased. Remarkably, the levels of reactive oxidative species (ROS), malondialdehyde (MDA), and lactate dehydrogenase (LDH) were observed to be repressed, while the levels of superoxide dismutase (SOD) was significantly increased. More importantly, the levels of tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, IL-6, and interferon (IFN)-γ were decreased.

Conclusions

Remifentanil has significant potential as a therapeutic intervention strategy for ameliorating myocardial injury after MI and these findings provide the rationale for further clinical studies.

Effect of pectoral nerve block type II under general anesthesia on the immune function of patients with breast cancer

BACKGROUND

To investigate whether the use of Pecs II block benefit patients with the respect to the immune functions.

METHODS

Totally 196 patients were included in this study. These patients were randomized to two groups, general anesthesia alone group (G group) and Pectoral nerve (Pecs) II block under general anesthesia group (PG group).

RESULTS

It was found that remifentanil consumption was less in PG group than it in G group. PG group showed a higher proportion of NK cells in peripheral blood mononuclear cell (PBMC) and an improved killing activity than G groups after surgery. We also found that postoperative interleukin (IL)-2 concentration in the plasma of PG group was dramatically higher than it of G group. Interestingly, there was even no significant change between preoperative and postoperative IL-2 levels in PG group, suggesting the less inhibitory effect of Pecs II block on immune system of those patients.

CONCLUSIONS

In conclusion, these results indicate that Pecs II block use in patients may have an enhanced immunity compared with general anesthesia method.

Anesthetic Strategies in Oncological Surgery: Not Only a Simple Sleep, but Also Impact on Immunosuppression and Cancer Recurrence

Tumor recurrences or metastases remain a major hurdle in improving overall cancer survival. In the perioperative period, the balance between the ability of the cancer to seed and grow at the metastatic site and the ability of the patient to fight against the tumor (i.e. the host antitumor immunity) may determine the development of clinically evident metastases and influence the patient outcome. Up to 80% of oncological patients receive anesthesia and/or analgesia for diagnostic, therapeutic or palliative interventions. Therefore, anesthesiologists are asked to administer drugs such as opiates and volatile or intravenous anesthetics, which may determine different effects on immunomodulation and cancer recurrence. For instance, some studies suggest that intravenous drugs, such as propofol, may inhibit the host immunity to a lower extent as compared to volatile anesthetics. Similarly, some studies suggest that analgesia assured by local anesthetics may provide a reduction of cancer recurrence rate; whilst on the opposite side, opioids may exert negative consequences in patients undergoing cancer surgery, by interacting with the immune system response via the modulation of the hypothalamic-pituitary-adrenal axis and autonomic nervous system, or directly through the opioid receptors on the surface of immune cells. In this review, we summarize the main findings on the effects induced by different drugs on immunomodulation and cancer recurrence.

Do All Opioid Drugs Share the Same Immunomodulatory Properties? A Review From Animal and Human Studies

Suppression of the immune system has been constantly reported in the last years as a classical side effect of opioid drugs. Most of the studies on the immunological properties of opioids refer to morphine. Although morphine remains the "reference molecule," other semisynthetic and synthetic opioids are frequently used in the clinical practice. The primary objective of this review is to analyze the available literature on the immunomodulating properties of opioid drugs different from morphine in preclinical models and in the human. A search strategy was conducted in PubMed, Embase, and the Cochrane databases using the terms "immunosuppression," "immune system," "opioids," "Natural killer cells," "cytokines," and "lymphocytes." The results achieved concerning the effects of fentanyl, methadone, oxycodone, buprenorphine, remifentanil, tramadol, and tapentadol on immune responses in animal studies, in healthy volunteers and in patients are reported. With some limitations due to the different methods used to measure immune system parameters, the large range of opioid doses and the relatively scarce number of participants in the available studies, we conclude that it is not correct to generalize immunosuppression as a common side effect of all opioid molecules.

Anti-inflammatory effect of remifentanil in lipopolysaccharide-stimulated amniotic epithelial cells

Background

Sometimes general anesthesia is required for dental surgery in pregnant women. Facial bone fractures or neck abscess should be treated immediately. Dental surgery, however, creates a stressful situation that can cause inflammation. Inflammatory responses are a well-known major cause of preterm labor and preterm birth. Here we demonstrate the effects of remifentanil on the factors related to preterm labor and its mechanism of action on amniotic-derived epithelial cells (WISH cells).

Methods

WISH cells were exposed to lipopolysaccharide (LPS) for 24 h and co-treated with various concentrations of remifentanil. MTT assays were performed to measure cell viability. To explain the effects of remifentanil on the factors related to inflammation in WISH cells, activation of nuclear factor kappa B (NF-κB) and p38 and the expression of interleukin (IL)-1β, tumor necrosis factor (TNF)-α, cyclooxygenase (COX)2, and prostaglandin E (PGE)₂ were quantified using western blotting and RT-PCR, respectively.

Results

Remifentanil did not affect WISH cell viability. In western blot analysis, co-treatment with remifentanil resulted in decreased phosphorylation of NF-κB, and expression of COX2 and PGE₂ in LPS-induced inflammation, but the results were statistically significant only at low concentrations. Reduction of IL-1β and TNF-α expression was also observed with RT-PCR.

Conclusion

Co-treatment with remifentanil does not affect the viability of WISH cells, but reduces the expression of the factors related to inflammation, which can induce uterine contraction and preterm labor. These findings provide evidence that remifentanil may inhibit uterine contraction and preterm labor in clinical settings.

Effects of propofol/remifentanil-based total intravenous anesthesia versus sevoflurane-based inhalational anesthesia on the release of VEGF-C and TGF-β and prognosis after breast cancer surgery: a prospective, randomized and controlled study

Background

Vascular endothelial growth factor (VEGF) and transforming growth factor-β (TGF-β) have been involved in tumor growth and metastasis. Sevoflurane may promote angiogenesis, whereas propofol can present an anti-angiogenic effect. In this study, we compared the effects of propofol/remifentanil-based total intravenous anesthesia (TIVA) and sevoflurane-based inhalational anesthesia on the release of VEGF-C and TGF-β, as well as recurrence- free survival (RFS) rates in the patients undergoing breast cancer surgery.

Methods

Eighty female patients undergoing breast cancer resection were enrolled and randomized to receive either sevoflurane-based inhalational anesthesia (SEV group) or propofol/remifentanil-based TIVA (TIVA group). The serum concentrations of VEGF-C and TGF-β before and 24 h after surgery were measured and RFS rates over a two-year follow-up were analyzed in both groups. The postoperative pain scores assessed using a visual analogue scale (VAS) and the use of perioperative opioids were also evaluated.

Results

Although VAS scores at 2 h and 24 h after surgery were comparable between the two groups, there were more patients receiving postoperative fentanyl in the TIVA group (16[40%]) compared with the SEV group (6[15%], p = 0.023). VEGF-C serum concentrations increased after surgery from 105 (87–193) pg/ml to174 (111–281) pg/ml in the SEV group (P = 0.009), but remained almost unchanged in the TIVA group with 134 (80–205) pg/ml vs.140(92–250) pg/ml(P = 0.402). The preoperative to postoperative change for VEGF-C of the SEV group (50 pg/ml) was significantly higher than that of the TIVA group (12 pg/ml) with a difference of 46 (− 11–113) pg/ml (P = 0.008). There were also no significant differences in the preoperative and postoperative TGF-β concentrations between the two groups. The two-year RFS rates were 78% and 95% in the SEV and TIVA groups (P = 0.221), respectively.

Conclusion

In comparison with sevoflurane-based inhalational anesthesia, propofol/remifentanil -based total intravenous anesthesia can effectively inhibit the release of VEGF-C induced by breast surgery, but didn’t seem to be beneficial in the short-term recurrence rate of breast cancer.

Trial registration

Chictr.org.cn ChiCTR1800017910. Retrospectively Registered (Date of registration: August 20, 2018).

Effects of surgery and anesthetic choice on immunosuppression and cancer recurrence

Background

The relationship between surgery and anesthetic-induced immunosuppression and cancer recurrence remains unresolved. Surgery and anesthesia stimulate the hypothalamic–pituitary–adrenal (HPA) axis and sympathetic nervous system (SNS) to cause immunosuppression through several tumor-derived soluble factors. The potential impact of surgery and anesthesia on cancer recurrence was reviewed to provide guidance for cancer surgical treatment.

Methods

PubMed was searched up to December 31, 2016 using search terms such as, “anesthetic technique and cancer recurrence,” “regional anesthesia and cancer recurrence,” “local anesthesia and cancer recurrence,” “anesthetic technique and immunosuppression,” and “anesthetic technique and oncologic surgery.”

Results

Surgery-induced stress responses and surgical manipulation enhance tumor metastasis via release of angiogenic factors and suppression of natural killer (NK) cells and cell-mediated immunity. Intravenous agents such as ketamine and thiopental suppress NK cell activity, whereas propofol does not. Ketamine induces T-lymphocyte apoptosis but midazolam does not affect cytotoxic T-lymphocytes. Volatile anesthetics suppress NK cell activity, induce T-lymphocyte apoptosis, and enhance angiogenesis through hypoxia inducible factor-1α (HIF-1α) activity. Opioids suppress NK cell activity and increase regulatory T cells.

Conclusion

Local anesthetics such as lidocaine increase NK cell activity. Anesthetics such as propofol and locoregional anesthesia, which decrease surgery-induced neuroendocrine responses through HPA-axis and SNS suppression, may cause less immunosuppression and recurrence of certain types of cancer compared to volatile anesthetics and opioids.

Differences in immune response to anesthetics used for day surgery versus hospitalization surgery for breast cancer patients

BACKGROUND

Surgery/anesthetic technique-stimulated immunosuppression may be associated with outcome for cancer patients. Here, the immune responses of patients undergoing day surgery versus hospitalization surgery for breast cancer were compared in a prospective study.

METHODS

Between February 2012 and August 2014, 21 breast cancer patients underwent day surgery and 16 breast cancer patients underwent hospitalization surgery. The former group received lidocaine/propofol/pethidine, while propofol/systemic opioid- and sevoflurane/propofol/systemic opioid-based anesthesia were administered to the latter group. Surgical stress response was evaluated based on time of operation and amount of bleeding during operation. Immune function was assessed based on natural killer (NK) cell activity, CD4/8 T cell ratio, and cytokine levels of IL-6 and IL-10 that were detected before surgery, after surgery, and on the first postoperative day.

RESULTS

Operation time did not differ between the two groups. Blood loss was significantly less for the hospitalization surgery group. No change in NK cell activity was observed for either group, although the CD4/8 T cell ratio increased transiently following day surgery. Levels of IL-6 increased significantly in both groups following surgery, and these levels tended to be higher in the hospitalization surgery group. One patient who underwent hospitalization surgery had higher levels of IL-10.

CONCLUSIONS

There were few differences in immune response between the two groups, potentially since a majority of the hospitalization surgery patients received propofol-based anesthesia. We hypothesize that the use of volatile anesthetic/opioid analgesia in hospitalization surgery has a greater influence on immune function in breast cancer patients than local anesthetic/propofol-based anesthesia in day surgery.

Anti-inflammatory properties of anesthetic agents

This article is one of ten reviews selected from the Annual Update in Intensive Care and Emergency Medicine 2017. Other selected articles can be found online at http://ccforum.com/series/annualupdate2017. Further information about the Annual Update in Intensive Care and Emergency Medicine is available from http://www.springer.com/series/8901.

The Effects of Remifentanil on Expression of High Mobility Group Box 1 in Septic Rats

High mobility group box 1 (HMGB1) is a pivotal mediator of sepsis progression. Remifentanil, an opioid agonist, has demonstrated anti-inflammatory effects in septic mice. However, it is not yet known whether remifentanil affects the expression of HMGB1. We investigated the effects of remifentanil on HMGB1 expression and the underlying mechanism in septic rats. Forty-eight male Sprague-Dawley rats were randomly divided into 3 groups; a sham group, a cecal ligation and puncture (CLP) group, and a CLP with remifentanil treatment (Remi) group. The rat model of CLP was used to examine plasma concentrations of proinflammatory cytokines, tissue HMGB1 mRNA and the activity of nuclear factor (NF)-κB in the liver, lungs, kidneys, and ileum. Pathologic changes and immunohistochemical staining of NF-κB in the liver, lungs, and kidneys tissue were observed. We found that remifentanil treatment suppressed the level of serum interleukin (IL)-6 and tumor necrosis factor (TNF)-α 6 hours after CLP, and serum HMGB1 24 hours after CLP. HMGB1 mRNA levels and the activity of NF-κB in multiple organs decreased by remifentanil treatment 24 hours after CLP. Remifentanil treatment also attenuated nuclear expression of NF-κB in immunohistochemical staining and mitigated pathologic changes in multiple organs. Altogether, these results suggested that remifentanil inhibited expression of HMGB1 in vital organs and release of HMGB1 into plasma. The mechanism was related to the inhibitory effect of remifentanil on the release of proinflammatory cytokines and activation of NF-κB.

Remifentanil-induced alterations in neutrophil numbers after surgery

Background

Neutrophils are the first line of defense against invasive microorganisms during and after surgery. There is a possibility that different opioid analgesics used during surgery have different effects on the leucocyte count. We retrospectively analyzed the numbers of leucocytes, neutrophils, and lymphocytes just after surgery in patients who received remifentanil-based anesthesia and those who received fentanyl-based anesthesia.

In female patients who underwent modified mastectomy or simple mastectomy with resection of a lymph node(s) or with biopsy of a sentinel lymph node(s) between January 2010 and December 2013 (n = 83), propensity score pairwise matching was performed according to the patient’s age and procedure, and forty patients (Remifentanil group and Fentanyl group; n = 20 each) were analyzed.

Findings

Postoperative numbers of leucocytes and neutrophils were significantly lower in patients who received remifentanil-based anesthesia than in those who received fentanyl-based anesthesia (p = 0.03, p = 0.014; leucocytes and neutrophils, respectively). The increases in the numbers of leucocytes and neutrophils were significantly lower in the patients in the remifentanil group (p = 0.009, p = 0.0046; increase in leucocytes and neutrophils, respectively).

Conclusions

In conclusion, remifentanil-based anesthesia attenuates postoperative leucocyte and neutrophil counts. It is unknown whether this phenomenon indicates the possibility of immunosuppression. Further studies are required.

Effects of propofol-based total intravenous anesthesia on recurrence and overall survival in patients after modified radical mastectomy: a retrospective study

Background

The optimal combination of anesthetic agent and technique may have an influence on long-term outcomes in cancer surgery. In vitro and in vivo studies suggest that propofol independently reduces migration of cancer cells and metastasis. Thus, the authors retrospectively examined the link between propofol-based total intravenous anesthesia (TIVA) and recurrence or overall survival in patients undergoing modified radical mastectomy (MRM).

Methods

A retrospective analysis of the electronic database of all patients undergoing MRM for breast cancer between January 2007 and December 2008 was undertaken. Patients received either propofol-based TIVA (propofol group) or sevoflurane-based anesthesia (sevoflurane group). We analyzed prognostic factors of breast cancer and perioperative factors and compared recurrence-free survival and overall survival between propofol and sevoflurane groups.

Results

A total of 363 MRMs were carried out during the period of the trial; 325 cases were suitable for analysis (173 cases of propofol group, and 152 cases of sevoflurane group). There were insignificant differences between the groups in age, weight, height, histopathologic results, surgical time, or postoperative treatment (chemotherapy, hormonal therapy, and radiotherapy). The use of opioids during the perioperative period was greater in propofol group than in sevoflurane group. Overall survival was no difference between the two groups. Propofol group showed a lower rate of cancer recurrence (P = 0.037), with an estimated hazard ratio of 0.550 (95% CI 0.311–0.973).

Conclusions

This retrospective study provides the possibility that propofol-based TIVA for breast cancer surgery can reduce the risk of recurrence during the initial 5 years after MRM.

Remifentanil attenuates lipopolysaccharide-induced acute lung injury by downregulating the NF-κB signaling pathway

Remifentanil significantly represses cell immune responses and influences neutrophil migration through endothelial cell monolayers. The present study determines the beneficial effects of remifentanil and the mechanisms by which it attenuates lipopolysaccharide (LPS)-induced acute lung injury (ALI). Rats were intratracheally instilled with 2 mg/kg LPS to induce ALI. Results showed that remifentanil could resolve lung injury, as evidenced by remarkable decreases in lung edema (wet-to-dry weight ratio), neutrophil infiltration (myeloperoxidase activity), and pulmonary permeability [total number of cells and protein concentrations in bronchoalveolar lavage fluid (BALF)]. Remifentanil also attenuated the concentrations of proinflammatory cytokines tumor necrosis factor alpha, interleukin-1β, and interleukin-6 in BALF, as well as effectively repressed the activation of nuclear factor-kappaB (NF-κB), which has been associated with the inhibition of IκBα degradation.These results suggest that remifentanil may be a suitable treatment for LPS-induced ALI. Remifentanil exerts beneficial effects on the inhibition of proinflammatory cytokine production by downregulating the NF-κB pathway.

Immunosuppressive aspects of analgesics and sedatives used in mechanically ventilated patients: an underappreciated risk factor for the development of ventilator-associated pneumonia in critically ill patients

OBJECTIVE

To evaluate the evidence describing the immunosuppressive and pharmacokinetic properties of commonly used analgesic and sedation agents in critically ill patients.

DATA SOURCES

MEDLINE (January 1980-September 2013) was searched.

STUDY SELECTION AND DATA EXTRACTION

All in vitro and in vivo studies that evaluated the immune-modulating properties of analgesic and sedation agents commonly used in the critically ill were included. Full-text and abstract-only articles (noted) were included in this review. Inclusion criteria were met by 46 studies and were evaluated.

DATA SYNTHESIS

Analgesic and sedation agents have been shown to be immunosuppressive in a variety of models. In vitro models use a variety of immune cells to demonstrate the immunosuppressive properties of opioids, benzodiazepines, and to a lesser extent, propofol. In each case, animal studies provide more robust data supporting the concept that opioids, benzodiazepines, and propofol exhibit immunosuppressive activities ranging from innate to adaptive immune alterations. Human studies, though more limited, provide further support that these agents inhibit the immune response. In contrast, data have shown that dexmedetomidine may attenuate the immune system. Clinical trial data evaluating the immunosuppressive properties of these agents is limited.

CONCLUSIONS

Analgesic and sedation agents have clearly been shown to alter cellular function and other mediators of the immune system; yet the clinical impact remains to be fully elucidated. The mechanism by which sedation interruption reduces ventilator-associated pneumonia may in fact be a reduction in immunosuppressive effects. Studies linking the immune-modulating effects of analgesic and sedation agents in critically ill patients are needed.

[Recommendations for symptomatic therapy of rheumatic pain with opioid analgetics]

The treatment of musculoskeletal pain is often difficult. For this reason opioids are increasingly being used for chronic musculoskeletal complaints despite poor or lacking evidence for their pain relieving and function improving effects. However, side effects are common and can be severe. Opioid-induced hyperalgesia can lead to higher doses and stronger pain and increase the risk of side effects. Long-term treatment of rheumatic pain with opioids should be carried out with caution.

Remifentanil ameliorates intestinal ischemia-reperfusion injury

Background

Intestinal ischemia-reperfusion injury (IRI) can occur in clinical scenarios such as organ transplantation, trauma and cardio-pulmonary bypass, as well as in neonatal necrotizing enterocolitis or persistent ductus arteriosus. Pharmacological protection by pretreating (“preconditioning”) with opioids attenuates IRI in a number of organs. Remifentanil appears particularly attractive for this purpose because of its ultra-short duration of action and favorable safety profile. To date, little is known about opioid preconditioning of the intestine.

Methods

Young adult C57BL/6J mice were randomly assigned to receive tail vein injections of 1 μg/kg of remifentanil or normal saline and underwent either ischemia-reperfusion of the intestine or a sham laparotomy. Under isoflurane anesthesia, the mice were subjected to intestinal ischemia-reperfusion by occlusion (clamping) of the superior mesenteric artery for 30 min, followed by unclamping and 60 min of reperfusion. After completion of this protocol, tissue injury and lipid peroxidation in jejunum and ileum were analyzed by histology and malondialdehyde (MDA), respectively. Systemic interleukin (IL)-6 was determined in the plasma by ELISA.

Results

Pretreatment with remifentanil markedly reduced intestinal IRI (P < 0.001): In the ileum, we observed a more than 8-fold decrease in injured villi (4% vs 34% in saline-pretreated animals). In fact, the mucosa in the remifentanil group was as healthy as that of sham-operated animals. This protective effect was not as pronounced in the jejunum, but the percentage of damaged villi was still reduced considerably (18% vs 42%). There was up to 3-fold more tissue MDA after intestinal ischemia-reperfusion than after sham laparotomy, but this increase in lipid peroxidation was prevented by preconditioning with remifentanil (P < 0.05). The systemic inflammatory response triggered by intestinal IRI was significantly attenuated in mice pretreated with remifentanil (159 vs 805 pg/ml of IL-6 after saline pretreatment, with 92 pg/ml in the sham groups). After sham operations, no difference was detected between the saline- and remifentanil-pretreatments in any of the parameters investigated.

Conclusion

Preconditioning with remifentanil attenuates intestinal IRI and the subsequent systemic inflammatory response in mice. We therefore suggest that prophylaxis with this ultra-short-acting opioid may be advantageous in various clinical scenarios of human IRI.

[Perioperative tumour dissemination. 2. Effects of anaesthesia and analgesia]

There has been growing concern over the last few years on the effect that the anaesthetic drugs used during oncological surgery could have on long-term tumour progression. In laboratory studies, it has been observed how some substances used during the anaesthetic procedure influence tumour immunosurveillance, cell proliferation or tumour angiogenesis processes. The possible clinical relevance of the anaesthetic technique used as regards long-term tumour progression and survival is still to be determined. However, based on retrospective studies, it appears that those anaesthetic techniques combined with the use of regional anaesthesia and analgesia may be beneficial compared to those that are maintained on the use of opioids. Further research should help to clarify the long-term clinical relevance of the anaesthetic process during oncological surgery.

Selective Neurogenic Blockade and Perioperative Immune Reactivity in Patients Undergoing Lung Resection

OBJECTIVE: This double-blind, prospective, randomized, controlled trial examined the effects of thoracic epidural block and intravenous clonidine and opioid treatment on the postoperative Th1/Th2 cytokine ratio after lung surgery. The primary endpoint was the interferon γ (IFN-γ; Th1 cytokine)/interleukin 4 (IL-4; Th2 cytokine) ratio. Secondary endpoints were reductions in pain and incidence of pneumonia. METHODS: Sixty patients were randomized into three groups to receive remifentanil intravenously (remifentanil group, n = 20), remifentanil and clonidine intravenously (clonidine group, n = 20), or ropivacaine epidurally (ropivacaine group, n = 20). Pain was assessed using a numerical rating scale (NRS). Cytokines were measured using a cytometric bead array. RESULTS: Patients in the ropivacaine group (thoracic epidural block) had a significantly lower IFN-γ/IL-4 ratio at the end of surgery than those in the remifentanil group and clonidine group. There were no significant between-group differences in the IFN-γ/IL-4 ratio at other time-points. There were no differences in NRS scores at any time-point. No patient developed pneumonia. CONCLUSION: Intraoperative thoracic epidural block decreased the IFN-γ/IL-4 ratio immediately after lung surgery, indicating less inflammatory stimulation during surgery.

Sedation & immunomodulation

As the armamentarium for sedation in the critically ill expands, opportunities will develop to modulate the immune responses of patients by way of the direct immune and neural-immune interactions of the sedatives. Control of autonomic activity through the use of appropriate sedation may be critical in this matter. Likewise analgesic-based sedation, with increased opioid dosage, may not prove beneficial in the setting of infection; whether avoidance of morphine in preference for a fentanyl derivative will help is unclear. However, as the immune effects seem dependent on the m receptor, it is improbable that a significant difference would be uncovered. Similarly, the present evidence suggests benzodiazepines are deleterious in infection; further studies are required urgently to evaluate this evidence. As an alternative to benzodiazepine-based sedation, dexmedetomidine has shown a remarkable 70% mortality benefit in a small secondary analysis of septic patients from the MENDS trial. Further powered clinical studies should now be undertaken to investigate the potential benefit of the α2-adrenoceptor agonist in this setting, with comparisons with propofol.

Morphine use in cancer surgery

Morphine is the core of perioperative pain management. However, when it comes to cancer surgery the possibility that this drug might affect tumor recurrence and metastasis has raised concerns. The results of two recent retrospective clinical trials indicated that regional anesthesia/analgesia might be beneficial in prostate and breast cancer surgery. It was proposed that morphine could be responsible for the higher recurrence and mortality rate observed in the general anesthesia/opioid analgesia groups. Nevertheless, the results of several other retrospective studies and one randomized prospective trial failed to confirm any advantage for regional anesthesia/analgesia over general anesthesia and opioid analgesia. Moreover laboratory data on the effect of morphine on cancer are contradictory, ranging from tumor-promoting to anti-tumor effects. Considering that surgical stress and pain promote the recurrence and spread of cancer, choosing a proper analgesic strategy is of high significance. Although the question of whether morphine causes any harm to cancer patients remains unanswered, alternative analgesic regimens could be used concomitant to or instead of morphine to limit its potential adverse effects.

Upregulation of SOCS-3 and PIAS-3 impairs IL-12-mediated interferon-gamma response in CD56 T cells in HCV-infected heroin users

Background

CD56⁺ T cells are abundant in liver and play an important role in host innate immunity against viral infections, including hepatitis C virus (HCV) infection, a common infection among heroin abusers. We thus investigated the in vivo impact of heroin use or heroin use plus HCV infection on the CD56⁺ T cell frequency and function.

Methodology/Principal Findings

A total of 37 heroin users with (17) or without (20) HCV infection and 17 healthy subjects were included in the study. Although there was no significant difference in CD56⁺ T cell frequency in PBMCs among three study groups, CD56⁺ T cells isolated from the heroin users had significantly lower levels of constitutive interferon-gamma (IFN-γ) expression than those from the normal subjects. In addition, when stimulated by interleukin (IL)-12, CD56⁺ natural T cells from HCV-infected heroin users produced significantly lower levels of IFN-γ than those from the normal subjects. This diminished ability to produce IFN-γ by CD56⁺ T cells was associated with the increased plasma HCV viral loads in the HCV-infected heroin users. Investigation of the mechanisms showed that although heroin use or heroin use plus HCV infection had little impact on the expression of the key positive regulators (IL-12 receptors, STAT-1, 3, 4, 5, JAK-2, and TYK-2) in IL-12 pathway, heroin use or heroin use plus HCV infection induced the expression of suppressor of cytokine signaling protein-3 (SOCS-3) and protein inhibitors of activated STAT-3 (PIAS-3), two key inhibitors of IL-12 pathway.

Conclusion/Significance

These findings provide compelling in vivo evidence that heroin use or heroin use plus HCV infection impairs CD56⁺ T cell-mediated innate immune function, which may account for HCV infection and persistence in liver.

Protective effects of remifentanil on septic mice

This study is to explore the effect of remifentanil on inducible nitric oxide synthase (iNOS) expression, IL-6 and IL-10 levels, myeloperoxidase (MPO) activity, white blood cell count in bronchoalveolar (BALF), ALT and AST activity in septic mice. Forty male KM mice were randomly divided into four groups, sham group, cecal ligation and puncture group (CLP group), remifentanil treatment group (R1 group), and remifentanil control group (R2 group). The mouse model of CLP was used to observe ALT and AST activity, white blood cell count in BALF and myeloperoxidase (MPO). IL-6 and IL-10 in lung and liver tissue were assayed by enzyme-linked immunosorbent assay (ELISA). Lung and liver tissues were harvested for determination of iNOS expression by Western blot analysis. The pathologic changes were observed under electron microscope. Compared with sham group, iNOS protein expression, white blood cell count in BALF, ALT and AST activity, MPO activity, IL-6 and IL-10 levels were markedly increased in CLP group. Compared with CLP group, iNOS protein expression, IL-6 and IL-10 levels, white blood cell count in BALF, ALT and AST activity, MPO activity of R1 group were significantly lower. The pathologic changes induced by sepsis were significantly attenuated by remifentanil under electron microscope. Remifentanil could suppress inflammatory responses and inhibit iNOS expression in septic mice. Remifentanil might have a protective effect against sepsis. Its action mechanisms are probably involved in the inhibition of inflammatory factor production and suppression of iNOS expression.

[Could anaesthesia, analgesia and sympathetic modulation affect neoplasic recurrence after surgery? A systematic review centred over the modulation of natural killer cells activity]

OBJECTIVE

The Natural Killer cells (NK) are an important part of non-specific cellular-mediated and antitumoral immunity. The goal of this review is to recapitulate data published over NK activity during the perioperative period and the influence of anaesthesia, analgesia and modulation of sympathetic system.

DATA SOURCES

Pubmed/Medline database.

STUDY SELECTION AND DATA EXTRACTION

Keywords-based selection, without limit of date: fundamental studies, randomized controlled trials and non-randomized comparative studies.

DATA SYNTHESIS

In human as in animal studies, an important correlation exists between NK activity and prognosis linked to the development of metastasis. The great depression of this cytotoxicity during the perioperative period could be able to compromise host defenses. The influence of anaesthetics and analgesics is important. The effects of the opioids, the agonists and the antagonists of the sympathetic nervous system, the prostaglandins, the NSAIDs, the ketamine, the hypnotics and the locoregional anaesthesia are systematically reviewed. The limits of experimental model presented are covered.

CONCLUSION

The effects of anaesthetic/analgesic drugs and techniques, the consequences of sympathomodulation on NK activity are numerous and sometimes opposite. It is important for the anaesthesiologist to keep in mind that the long term consequences of his techniques on the patients' outcome must be clarified.

Sedation & immunomodulation

The management of critically ill patients necessitates the use of sedatives and analgesics to provide patient comfort and cooperation. These drugs exert profound effects on all organ systems, not only the central nervous system, and this article describes the immunologic effects of the commonly used critical care sedatives: propofol, the benzodiazepines, opioids, and alpha(2)-adrenoceptor agonists. Benzodiazepines, opioids, and possibly even propofol worsen outcome in animal models of infection, whereas preliminary evidence suggests that the alpha(2)-adrenoceptor agonist, dexmedetomidine, may improve outcomes in the setting of infection. Given the burden of sepsis and secondary infections in critical care, choice of sedation may need to be carefully considered to preserve immune responses in critically ill patients.

Effects of remifentanyl and fentanyl on LPS-induced cytokine release in human whole blood in vitro

Aim The present study sought insight into the effects of remifentanyl and fentanyl on LPS-induced release of interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha) and IL-10 in human whole blood. Methods Whole blood was incubated in the presence and absence of remifentanyl and fentanyl. Effects of remifentanyl and fentanyl on spontaneous and endotoxin (lipopolysaccharide; 100 ng ml(-1))-stimulated cytokine release were studied in whole blood from volunteers (n = 10) cultured for 6 h. Results IL-6, TNF-alpha and IL-10 concentrations in groups added with LPS were significantly higher than those in control group (P < 0.01). IL-6, TNF-alpha and IL-10 concentrations in activation groups treated with remifentanyl or fentanyl were significantly lower than those in LPS treated group (P < 0.05). There were no significant differences on IL-6,TNF-alpha and IL-10 concentrations in drug-alone groups compared with control group (P > 0.05). Conclusion Remifentanyl or fentanyl alone has no effects on IL-6, TNF-alpha and IL-10 production, but could attenuate LPS-induced IL-6,TNF-alpha and IL-10 production in human whole blood. Remifentanyl and fentanyl could inhibit the expressions of IL-6, TNF-alpha and IL-10 induced by LPS.

Comparison of the Modulatory Effects of Four Different Fast-Track Anesthetic Techniques on the Inflammatory Response to Cardiac Surgery With Cardiopulmonary Bypass

OBJECTIVES

To test the hypothesis that the choice of anesthesia technique for coronary artery surgery influences the degree and magnitude of the subsequent inflammatory response and its consequences.

DESIGN

Prospective, randomized, comparative study.

SETTING

Major university teaching hospital.

PARTICIPANTS

Sixty patients undergoing elective surgery.

INTERVENTIONS

Patients were randomized into an alfentanil group, a high-dose remifentanil group, a low-dose remifentanil group, or a thoracic epidural group, in combination with a propofol target-controlled infusion. The study was blinded for the opioid, except in the epidural group. Tight control of perioperative hemodynamic parameters was maintained, and the postoperative management was strictly standardized. Bactericidal permeability-increasing protein as an indicator of the polymorphonuclear neutrophil response, interleukin-6 as an inducer of the acute-phase response, and lipopolysaccharide-binding protein and C-reactive protein as parameters of the acute phase response were determined at regular intervals. Ventilator dependency and analgesia were evaluated as clinical outcome measures.

MEASUREMENTS AND MAIN RESULTS

Interleukin-6 levels increased in all groups. Plasma levels in the epidural group were significantly higher at all time points than in the other groups. The increase in the plasma levels of bactericidal permeability-increasing protein, lipopolysaccharide-binding protein, and C-reactive protein showed the same pattern in all groups, and no significant differences among the 4 groups were observed.

CONCLUSIONS

Supplementation of a fast-track anesthetic technique with epidural analgesia preserves hemodynamic stability and is associated with faster extubation times (p = 0.003) and less postoperative pain (p = 0.045). Thoracic epidural analgesia was associated with significantly higher levels of IL-6 throughout the study period as compared with the total intravenous anesthesia groups. The exact clinical relevance of this finding remains unclear.

Pain management: is opioid immunosuppression a clinical problem?

For more than 100 years, the use of opioid analgesic agents has been linked with modulation of the immune system in man. More recently, it has become apparent that both exogenous and endogenous opioids exert some effect upon the immune system but that this can be beneficial or deleterious depending on numerous variables. Of the strong opioid analgesics in current use, the majority are seen to cause immunosuppression in man. However, it still remains unclear whether this is clinically important in man although it would appear to be good practice to avoid such agents in patients already immunosuppressed by disease or pharmacotherapy. Powerful opioid analgesics without immunosuppressive properties can be selected and should be used in such situations and as these agents can offer additional benefits in addition to their non-immunosuppresive analgesia, it should be considered whether to use them at all times in preference to immunosuppressive opioids.

Effects of general anaesthesia on inflammation

General anaesthesia accompanied by surgical stress may influence the inflammatory responses that are essential for maintaining the homeostatic state during the postoperative course. Severe dysregulation of the inflammatory process may provoke or aggravate postoperative complications, e.g. increased susceptibility to infections, inadequate stress reactions and hypercatabolism. Anaesthetics have been suspected of impairing various functions of the immune system either directly, by disturbing the functions of immune-competent cells, or indirectly by modulating the stress response. In the past, conflicting data on the possible immunological side effects of anaesthetics have been published. Potential reasons for these controversial findings include heterogeneous patient study groups with diverse pre-existing diseases, lack of standardisation of surgical procedures, major differences in the length and severity of surgical tissue injury and a small number of randomised studies. Although the immunological effects are of minor consequence in subjects with normal immune functions, the suppression of cellular and humoral immunity following surgery and general anaesthesia may be relevant in patients with pre-existing immune disorders.

Low-dose remifentanil infusion does not impair natural killer cell function in healthy volunteers

BACKGROUND

Mu opioid agonists suppress natural killer (NK) cell activity in animal models. Studies in human volunteers, however, have yielded conflicting results, with morphine suppressing and fentanyl increasing NK cell activity. This study evaluated the effect of a constant 8-h infusion of remifentanil on NK cell number and function in human volunteers.

METHODS

After IRB approval and informed consent was obtained, 10 healthy volunteers underwent an 11 pm to 7 am infusion of saline, and at least 1 week later an infusion of 0.02-0.04 microg x kg(-1) min(-1) remifentanil. Blood was collected at 7 am for measurement of NK cell cytotoxicity using a (51)Cr release assay and measurement of NK cell number using fluorescent flow cytometry.

RESULTS

Median and range of the total NK cell cytotoxicity (KU ml(-1)) was 745.0 (498.3-1483.6) on the control morning and 818.6 (238.5-1454.5) on the morning following the remifentanil infusion. Neither the number of NK cells ml(-1) (2.5 x 10(5) (1.4 x 10(5)-4.2 x 10(5)) vs 2.7 x 10(5) (1.1 x 10(5)-4.4 x 10(5))) nor the cytotoxicity per 1000 NK cells (KU 1000 NK cells(-1)) (3.0 (1.8-5.2) vs 2.9 (0.9-6.7)) changed between the control and remifentanil conditions.

CONCLUSIONS

An 8-h infusion of remifentanil did not affect NK cell activity in normal volunteers. This result differs from previous findings of morphine-induced NK cell activity suppression and fentanyl-induced NK cell activity enhancement in normal volunteers.

Opioid-induced immunosuppression: is it centrally mediated or peripherally mediated?

Opioid compounds are commonly used pain medications. However, their administration is associated with a number of side-effects. Among them, opioid-induced immunosuppression is a significant medical problem, which is evidenced by a strong association between the use of opioids and exacerbated infections, including AIDS. Research data have demonstrated the effects of opioids to be suppressive on phagocytic, natural killer (NK), B and T cells. However, these immunosuppressive effects may be mediated by mechanisms different from those for antinociceptive actions. This article reviews possible central and peripheral mechanisms of opioid-induced immunosuppression. To the extent that peripherally mediated immunosuppressive effects play a significant role in opioid-induced immunosuppression, novel peripheral opioid antagonists may have a therapeutic role in attenuating opioid-induced immunosuppression without affecting analgesia.