Sedative drug modulates T-cell and lymphocyte function-associated antigen-1 function

Influence of Perioperative Anesthesia on Cancer Recurrence: from Basic Science to Clinical Practice

PURPOSEOF REVIEW

In this review, we will summarize the effects of these perioperative anesthetics and anesthetic interventions on the immune system and tumorigenesis as well as address the related clinical evidence on cancer-related mortality and recurrence.

RECENT FINDINGS

Cancer remains a leading cause of morbidity and mortality worldwide. For many solid tumors, surgery is one of the major therapies. Unfortunately, surgery promotes angiogenesis, shedding of circulating cancer cells, and suppresses immunity. Hence, the perioperative period has a close relationship with cancer metastases or recurrence. In the perioperative period, patients require multiple anesthetic management including anesthetics, anesthetic techniques, and body temperature control. Preclinical and retrospective studies have found that these anesthetic agents and interventions have complex effects on cancer outcomes. Therefore, well-planned, prospective, randomized controlled trials are required to explore the effects of different anesthetics and techniques on long-term outcomes after cancer surgery. Due to the conflicting effects of anesthetic management on cancer recurrence, further preclinical and clinical trials are required and beneficial to the development of systemic cancer therapies.

Effects of propofol and sevoflurane on T-cell immune function and Th cell differentiation in children with SMPP undergoing fibreoptic bronchoscopy

OBJECTIVES

The potentially different effects of commonly used anaesthetic agents propofol and sevoflurane on T-cell immune function and Th cell differentiation were investigated in patients with severe mycoplasmal pneumonia (SMPP) undergoing fibreoptic bronchoscopy.

METHODS

Sixty children (2-12 years of age) with SMPP were randomized into the sevoflurane group and the propofol group. Patients in the sevoflurane group were anaesthetised with inhalational sevoflurane and intravenous remifentanil. Patients in the propofol group were anaesthetised with intravenous propofol and remifentanil. Patients in both groups underwent fibreoptic bronchoscopy and lavage therapy. We compared the clinical outcomes, cellular immunity function, and Th cell differentiation into Th1 and Th2 levels in both groups.

RESULTS

There was no significant difference in clinical outcomes and hospital stay between the two groups (7.94 vs 7.36, p > .05). However, the CD3⁺ T cells, CD4⁺ T cells, and CD4⁺/CD8⁺ in the propofol group were significantly higher than those in the sevoflurane group (T1 51.96 vs 48.33, T2 58.08 vs 55.31, p < .05). The ratio of Th₁/Th₂ in the two groups was significantly increased postoperatively in both groups (Sevoflurane 8.53 vs 7.23, Propofol 9.35 vs 7.18), and the propofol group was significantly higher than the sevoflurane group (9.35 vs 8.53, p < .05).

CONCLUSIONS

Propofol might have a less inhibitory effect on T lymphocytes in children with SMPP than sevoflurane. And propofol may have less impact on the differentiation of Th cells into Th₁ cells and better preserving the Th₁/Th₂ ratio than sevoflurane. KEY MESSAGESThe pathogenesis of SMPP is still unclear, likely through alveolar infiltration with neutrophils and lymphocytes, lymphocyte/plasma cell infiltrates in the peri-bronchovascular area, and immune dysfunction.Recent experimental and clinical studies showed that sevoflurane might have immunosuppressive effects, and multiple studies confirmed that the immune function of children with SMPP had been reduced.This study found that propofol administered in children with SMPP had a less inhibitory effect on T lymphocytes than inhalational sevoflurane, had little inhibitory effect on the differentiation of Th cells into Th1 cells, and better preserve Th1/Th2 ratio and maintain the balanced immune function.

Rules of thumb to obtain, isolate, and preserve porcine peripheral blood mononuclear cells

One of the most used biospecimens in immunology are peripheral blood mononuclear cells (PBMC). PBMC are particularly useful when evaluating immunity through responses of circulating B- and T-cells, during an infection, or after a vaccination. While several reviews and research papers have been published aiming to point out critical steps when sampling, isolating, and cryopreserving human PBMC -or even analyzing any parameter before sampling that could impair the immune assays' outcomes-, there are almost no publications in swine research dealing with these topics. As it has been demonstrated, several factors, such as stress, circadian rhythmicity, or the anticoagulant used have serious negative impact, not only on the separation performance of PBMC, but also on the ulterior immune assays. The present review aims to discuss studies carried out in humans that could shed some light for swine research. When possible, publications in pigs are also discussed. The main goal of the review is to encourage swine researchers to standardize protocols to obtain, manage and preserve porcine PBMC, as well as to minimize, or at least to consider, the bias that some parameters might induce in their studies before, during and after isolating PBMC.

Evaluation of microbial contamination on cuff syringe, cuff pressure gauge, and their surroundings in the operating room

Background

Some institutions reuse cuff syringes and do not periodically sterilize cuff pressure gauges. Pathogenic bacterial contamination of such equipment may increase the probability of pathogen transmission to patients during anesthetic procedures. Therefore, microbial contamination on cuff syringes, cuff pressure gauges, and their surroundings was assessed in the operating rooms of a university-affiliated tertiary care hospital in Japan.

Methods

This study was conducted between April and May 2019 in 14 operating suites at a hospital. The following sites in each operating suite were sampled: cuff syringe (inner/outer components), outer components of cuff pressure gauge, cuff syringe and cuff pressure gauge storage drawers, and computer mice. The swabs were directly streaked onto agar plates and incubated. Then, the bacterial species were identified using mass spectrometry.

Results

The highest bacterial isolation was observed in computer mice, followed by the outside of cuff pressure gauges and the drawers of cuff pressure gauges (92.9, 78.6, and 64.3%, respectively). Most of the identified bacteria belonged to the Bacillus species, with colonization rates of 85.7, 57.1, and 57.1% on computer mice, cuff pressure gauges, and cuff pressure gauge storage drawers, respectively. Coagulase-negative Staphylococcus was found in 35.7% of the specimens and was more prevalent on computer mice (71.4%), followed by on cuff pressure gauges (64.3%).

Conclusion

Anesthesiologists should be aware of the possible pathogen contamination risk from cuff syringes, cuff pressure gauges, or associated equipment and take appropriate infection control measures to minimize the risk of pathogenic transmission.

The Role of General Anesthetic Drug Selection in Cancer Outcome

Cancer remains to be the leading cause of death globally. Surgery is a mainstay treatment for solid tumors. Thus, it is critical to optimize perioperative care. Anesthesia is a requisite component for surgical tumor resection, and general anesthesia is given in the vast majority of tumor resection cases. Because anesthetics are growingly recognized as immunomodulators, it is critical to optimize anesthetic regimens for cancer surgery if the selection can affect outcomes. Here, we reviewed the role of volatile and intravenous anesthesia used for cancer surgery in cancer recurrence.

Impact of anesthetics on oncogenic signaling network: a review on propofol and isoflurane

Propofol as an intravenous anesthetic and isoflurane as an inhalational/volatile anesthetic continue to be an important part of surgical anesthetic interventions worldwide. The impact of these anesthetics on tumor progression, immune modulation, and survival rates of cancer patients has been widely investigated. Although most of the preclinical studies have provided a beneficial effect of propofol over isoflurane or other volatile anesthetics, several investigations have shown contradictory results, which warrant more preclinical and clinical studies. Propofol mostly exhibits antitumor properties, whereas isoflurane being a cost-effective anesthetic is frequently used. However, isoflurane has been also reported with protumorigenic activity. This review provides an overall perspective on the network of signaling pathways that may modulate several steps of tumor progression from inflammation, immunomodulation, epithelial-mesenchymal transition (EMT) to invasion, metastasis, angiogenesis, and cancer stemness and extracellular vesicles along with chemotherapeutic applications and clinical status of these anesthetics. A clear understanding of the mechanistic viewpoints of these anesthetics may pave the way for more prospective clinical trials with the ultimate goal of obtaining a safe and optimal anesthetic intervention that would prevent cancer recurrence and may influence better postoperative survival.

The effect of dexmedetomidine premedication on postoperative systemic inflammatory response in children undergoing hernia repair surgery: A randomized controlled trial

BACKGROUND

Surgery results in systemic inflammation, which can affect the central nervous system, leading to changes in mood, emotion, and behavior. Our previous study has shown that compared to midazolam, dexmedetomidine premedication effectively decreased children's postoperative anxiety.

AIM

To investigate whether dexmedetomidine infusion before hernia repair alleviates postoperative systemic inflammation in children and whether postoperative anxiety may be associated with postoperative inflammation.

METHODS

This prospective double-blind randomized controlled trial was conducted in 120 children scheduled to undergo elective hernia repair. Before anesthesia induction, all children received an intravenous infusion consisted of dexmedetomidine (n = 40; 0.5 µg/g, group D), midazolam (n = 40; 0.08 mg/kg, group M), or normal saline (n = 40; group C). One-way ANOVA with least significant difference multiple comparison test was used for multigroup comparisons of postoperative plasma levels of inflammatory cytokines and m-YPAS scores. Spearman rank correlation tests were used for analyzing m-YPAS scores with postoperative plasma levels of inflammatory cytokines.

RESULTS

Plasma levels of tumor necrosis factor-alpha (7.0 ± 1.6 vs. 8.1 ± 1.6, mean difference [95% CI]: 1.19 [0.26-2.11], p = .008) (pg/ml) and of interleukin-6 (1.8 ± 1.2 vs. 3.3 ± 1.6, mean difference [95% CI]: 1.49 [0.74-2.25], p < .001) (pg/ml) and neutrophils-to-lymphocyte ratio (1.0 ± 0.5 vs. 1.5 ± 0.7, mean difference [95% CI]: 0.48 [0.17-0.78], p < .001) were significantly lower in group D than in group C. Furthermore, compared to group M, group D showed significantly lower plasma tumor necrosis factor-alpha levels (7.0 ± 1.6 vs. 7.9 ± 1.9, mean difference [95% CI]: 0.96 [0.04-1.88], p = .04) (pg/ml) and interleukin-6 levels (1.8 ± 1.2 vs. 2.9 ± 1.5, mean difference [95% CI]: 1.06 [0.31-1.81], p = .004) (pg/ml), and neutrophil-to-lymphocyte ratio (1.0 ± 0.5 vs. 1.5 ± 0.6, mean difference [95% CI]: 0.42 [0.11-0.72], p = .004). Anxiety scores at postoperative 2 and 4 h in the three groups positively correlated with plasma levels of proinflammatory cytokines.

CONCLUSION

A single preoperative intravenous dexmedetomidine dose in children undergoing same-day surgery reduces postoperative systemic inflammation.

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.

Very-Short-Term Sleep Deprivation Slows Early Recovery of Lymphocytes in Septic Patients

Sleep plays an important role in immune function. However, the effects of very-short-term sleep deprivation on the early recovery of immune function after sepsis remain unclear. This study was conducted in the intensive care unit to investigate the effects of 2 consecutive days of sleep deprivation (SD) on lymphocyte recovery over the following few days in septic patients who were recovering from a critical illness. The patients' self-reports of sleep quality was assessed using the Richards–Campbell Sleep Questionnaire at 0 and 24 h after inclusion. The demographic, clinical, laboratory, treatment, and outcome data were collected and compared between the good sleep group and poor sleep group. We found that 2 consecutive days of SD decreased the absolute lymphocyte count (ALC) and ALC recovery at 3 days after SD. Furthermore, post-septic poor sleep decreased the plasma levels of atrial natriuretic peptide (ANP) immediately after 2 consecutive days of SD. The ANP levels at 24 h after inclusion were positively correlated with ALC recovery, the number of CD3⁺ T cells, or the number of CD3⁺ CD4⁺ cells in the peripheral blood on day 5 after inclusion. Our data suggested that very-short-term poor sleep quality could slow down lymphocyte recovery over the following few days in septic patients who were recovering from a critical illness. Our results underscore the significance of very-short-term SD on serious negative effects on the immune function. Therefore, it is suggested that continuous SD or several short-term SD with short intervals should be avoided in septic patients.

The Role of Anesthetic Selection in Perioperative Bleeding

Perioperative bleeding is one of the major comorbidities associated with surgery. While anesthesia is a critical component to perform surgery, a number of clinical studies supported the contribution of anesthetic drugs to perioperative bleeding. Here, we reviewed the literature on this topic including the underlying mechanism and discussed the future direction on coagulation research in anesthesia.

Anesthetic technique and cancer surgery outcomes

PURPOSE OF REVIEW

Surgery remains integral to treating solid cancers. However, the surgical stress response, characterized by physiologic perturbation of the adrenergic, inflammatory, and immune systems, may promote procancerous pathways. Anesthetic technique per se may attenuate/enhance these pathways and thereby could be implicated in long-term cancer outcomes.

RECENT FINDINGS

To date, clinical studies have predominantly been retrospective and underpowered and, thus limit meaningful conclusions. More recently, prospective studies of regional anesthesia for breast and colorectal cancer surgery have failed to demonstrate long-term cancer outcome benefit. However, based on the consistent observation of protumorigenic effects of surgical stress and that of volatile anesthesia in preclinical studies, supported by in vivo models of tumor progression and metastasis, we await robust prospective clinical studies exploring the role of propofol-based total intravenous anesthesia (cf. inhalational volatiles). Additionally, anti-adrenergic/anti-inflammatory adjuncts, such as lidocaine, nonsteroidal anti-inflammatory drugs and the anti-adrenergic propranolol warrant ongoing research.

SUMMARY

The biologic perturbation of the perioperative period, compounded by the effects of anesthetic agents, renders patients with cancer particularly vulnerable to enhanced viability of minimal residual disease, with long-term outcome consequences. However, low level and often conflicting clinical evidence equipoise currently exists with regards to optimal oncoanesthesia techniques. Large, prospective, randomized control trials are urgently needed to inform evidence-based clinical practice guidelines.

The immunomodulatory mechanism of dexmedetomidine

Dexmedetomidine has been increasingly introduced into the perioperative care of surgical patients. Because a subset of anesthetics/sedatives are immunomodulatory, it is critical to understand the role of dexmedetomidine in our host immune functions. Here we reviewed the role of dexmedetomidine in different immune cells. We also reviewed published clinical articles that described the role of dexmedetomidine in organ injury, cancer surgery, and infection. In animal studies, dexmedetomidine attenuated organ injury. In clinical studies, dexmedetomidine was associated with an improvement in outcomes in cardiac surgery and transplant surgery. However, there is a paucity in research examining how dexmedetomidine is associated with these outcomes. Further studies are needed to understand its clinical application from immunological standpoints.

The Characterization of Postoperative Mechanical Respiratory Requirement in Neonates and Infants Undergoing Cardiac Surgery on Cardiopulmonary Bypass in a Single Tertiary Institution

OBJECTIVES

Although neonates and infants undergoing cardiac surgery on cardiopulmonary bypass (CPB) are at high risk of developing perioperative morbidity and mortality, including lung injury, the intraoperative profile of lung injury in this cohort is not well-described. Given that the postoperative course of patients in the pediatric cardiac surgical arena has become increasingly expedited, the objective of this study was to characterize the profiles of postoperative mechanical ventilatory support in neonates and infants undergoing cardiac surgery on CPB and to examine the characteristics of lung mechanics and lung injury in this patient population who are potentially amendable to early postoperative recovery in a single tertiary pediatric institution.

DESIGN

A retrospective data analysis of neonates and infants who underwent cardiac surgery on cardiopulmonary bypass.

SETTING

A single-center, university teaching hospital.

PARTICIPANTS

The study included 328 neonates and infants who underwent cardiac surgery on cardiopulmonary bypass.

INTERVENTIONS

A subset of 128 patients were studied: 58 patients undergoing ventricular septal defect (VSD) repair, 36 patients undergoing complete atrioventricular canal (CAVC) repair, and 34 patients undergoing bidirectional Glenn (BDG) shunt surgery.

MEASUREMENTS AND MAIN RESULTS

Of the entire cohort, 3.7% experienced in-hospital mortality. Among all surgical procedures, VSD repair (17.7%) was the most common, followed by CAVC repair (11.0%) and BDG shunt surgery (10.4%). Of patients who underwent VSD repair, CAVC repair, and BDG shunt surgery, 65.5%, 41.7%, and 67.6% were off mechanical ventilatory support within 24 hours postoperatively, respectively. In all three of the surgical repairs, lung compliance decreased after CPB compared to pre-CPB phase. Sixty point three percent of patients with VSD repair and 77.8% of patients with CAVC repair showed a PaO₂/F_IO₂ (P/F) ratio of <300 after CPB. Post- CPB P/F ratios of 120 for VSD patients and 100 for CAVC patients were considered as optimal cutoff values to highly predict prolonged (>24 hours) postoperative mechanical ventilatory support. A higher volume of transfused platelets also was associated with postoperative ventilatory support ≥24 hours in patients undergoing VSD repair, CAVC repair, and BDG shunt surgery.

CONCLUSIONS

There was a high incidence of lung injury after CPB in neonates and infants, even in surgeries amendable for early recovery. Given that CPB-related factors (CPB duration, crossclamp time) and volume of transfused platelet were significantly associated with prolonged postoperative ventilatory support, the underlying cause of cardiac surgery-related lung injury can be multi-factorial.

Anesthetics isoflurane and sevoflurane attenuate flagellin-mediated inflammation in the lung

Isoflurane and sevoflurane are volatile anesthetics (VA) widely used in clinical practice to provide general anesthesia. We and others have previously shown that VAs have immunomodulatory effects and may have a significant impact on the progression of disease states. Flagellin is a component of Gram negative bacteria and plays a significant role in the pathophysiology of bacterial pneumonia through its binding to Toll-like Receptor 5 (TLR5). Our results showed that VAs, not an intravenous anesthetic, significantly attenuated the activation of TLR5 and the release of the neutrophil chemoattractant IL-8 from lung epithelial cells. Furthermore, flagellin-induced lung injury was significantly attenuated by VAs by inhibiting neutrophil migration to the bronchoalveolar space. The lungs of cystic fibrosis (CF) patients are highly colonized by Pseudomonas aeruginosa, which causes inflammation. The retrospective study of oxygenation in patients with CF who had received VA versus intravenous anesthesia suggested that VAs might have the protective effect for gas exchange. To understand the interaction between VAs and TLR5, a docking simulation was performed, which indicated that isoflurane and sevoflurane docked into the binding interphase between TLR5 and flagellin.

Risk factors for pediatric surgical site infection following neurosurgical procedures for hydrocephalus: a retrospective single-center cohort study

Background

Infection is a major complication following cerebral spinal fluid (CSF) diversion procedures for hydrocephalus. However, pediatric risk factors for surgical site infection (SSI) are currently not well defined. Because a SSI prevention bundle is increasingly introduced, the purpose of this study was to evaluate risk factors associated with SSIs following CSF diversion surgeries following a SSI bundle at a single quaternary care pediatric hospital.

Methods

We performed a retrospective cohort study of patients undergoing CSF diversion procedures from 2017 to 2019. SSIs were identified prospectively through continuous surveillance. We performed unadjusted logistic regression analyses and univariate analyses to determine an association between SSIs and patient demographics, comorbidities and perioperative factors to identify independent risk factors for SSI.

Results

We identified a total of 558 CSF diversion procedures with an overall SSI rate of 3.4%. The SSI rates for shunt, external ventricular drain (EVD) placement, and endoscopic third ventriculostomy (ETV) were 4.3, 6.9 and 0%, respectively. Among 323 shunt operations, receipt of clindamycin as perioperative prophylaxis and presence of cardiac disease were significantly associated with SSI (O.R. 4.99, 95% C.I. 1.27–19.70, p = 0.02 for the former, and O.R. 7.19, 95% C.I. 1.35–38.35, p = 0.02 for the latter). No risk factors for SSI were identified among 72 EVD procedures.

Conclusion

We identified receipt of clindamycin as perioperative prophylaxis and the presence of cardiac disease as risk factors for SSI in shunt procedures. Cefazolin is recommended as a standard antibiotic for perioperative prophylaxis. Knowing that unsubstantiated beta-lactam allergy label is a significant medical problem, efforts should be made to clarify beta-lactam allergy status to maximize the number of patients who can receive cefazolin for prophylaxis before shunt placement. Further research is needed to elucidate the mechanism by which cardiac disease may increase SSI risk after shunt procedures.

Surgical Site Infections and Perioperative Optimization of Host Immunity by Selection of Anesthetics

Surgical site infections are significant health care issues, and efforts to mitigate their occurrence have been ongoing worldwide, mainly focusing to reduce the spillage of microbes to the otherwise sterile tissues. Optimization of host immunity has been also recognized including temperature regulation (normothermia), adequate oxygenation, and glucose management. A number of papers have described the role of anesthetics in host immunity. The role of anesthetics in postoperative outcomes including surgical site infections has been also studied. We will review the current literature and propose the importance of anesthetic selection to potentially mitigate surgical site infections.

The effect of repetitive exposure to intravenous anesthetic agents on the immunity in mice

Introduction: This study was designed to assess the effect of repetitive exposure to intravenous anesthetic agents on the immunity in mice. Materials and Methods: The mice were divided into six groups: three intravenous anesthetic agents groups (dexmedetomidine, midazolam and propofol groups), and three corresponding control groups (C_D, C_M, and C_P groups). The intravenous injections were administered once per day for 5 days. The immunity of mice was checked after the last intravenous injection. Histopathology and immunochemistry of liver and kidneys were evaluated. Cytokine levels in the blood was also checked. vs. evaluated with cytokine levels in the blood. Results: Cluster of differentiation (CD)4⁺ T cells were significantly less expressed in dexmedetomidine and propofol groups, compared with the corresponding control groups [34.08 ± 5.63% in the dexmedetomidine group vs. 59.74 ± 8.64% in the C_D group, p < 0.05; 25.28 ± 7.28% in the propofol group vs. 61.12 ± 2.70% in the C_p group, p < 0.05]. Apoptosis of CD4⁺ T cells was increased significantly in dexmedetomidine and propofol groups, compared with the corresponding control groups. Histopathological findings of liver and kidneys did not show any specific differences of any of three intravenous anesthetic agents groups with their corresponding control groups, although immunohistochemical examination indicated significantly lower expression of Toll-like receptor-4 from liver and kidneys in dexmedetomidine and propofol groups. The cytokine levels were not different between the groups. Conclusion: Repetitive exposure to dexmedetomidine and propofol reduced the expression of CD4⁺ T cells but did not induce any significant liver or kidney injuries.

The influence of dexmedetomidine and propofol on circulating cytokine levels in healthy subjects

Background

Surgery and diseases modify inflammatory responses and the immune system. Anesthetic agents also have effects on the human immune system but the responses they induce may be altered or masked by the surgical procedures or underlying illnesses. The aim of this study was to assess how single-drug dexmedetomidine and propofol anesthesia without any surgical intervention alter acute immunological biomarkers in healthy subjects.

Methods

Thirty-five healthy, young male subjects were anesthetized using increasing concentrations of dexmedetomidine (n = 18) or propofol (n = 17) until loss of responsiveness (LOR) was detected. The treatment allocation was randomized. Multi-parametric immunoassays for the detection of 48 cytokines, chemokines and growth factors were used. Concentrations were determined at baseline and at the highest drug concentration for each subject.

Results

The changes in the concentration of eotaxin (decrease after dexmedetomidine) and platelet-derived growth factor (PDGF, increase after propofol) were statistically significantly different between the groups. Significant changes were detected within both groups; the concentrations of monocyte chemotactic protein 1, chemokine ligand 27 and macrophage migration inhibitory factor were lower in both groups after the drug administration. Dexmedetomidine decreased the concentration of eotaxin, interleukin-18, interleukin-2Rα, stem cell factor, stem cell growth factor and vascular endothelial growth factor, and propofol decreased significantly the levels of hepatocyte growth factor, IFN-γ-induced protein 10 and monokine induced by IFN-γ, and increased the levels of interleukin-17, interleukin-5, interleukin-7 and PDGF.

Conclusions

Dexmedetomidine seemed to have an immunosuppressive effect on the immune system whereas propofol seemed to induce mixed pro- and anti-inflammatory effects on the immune system. The choice of anesthetic agent could be relevant when treating patients with compromised immunological defense mechanisms.

Trial registration

Before subject enrollment, the study was registered in the European Clinical Trials database (EudraCT number 2013–001496-21, The Neural Mechanisms of Anesthesia and Human Consciousness) and in ClinicalTrials.gov (Principal Investigator: Harry Scheinin, number NCT01889004, The Neural Mechanisms of Anesthesia and Human Consciousness, Part 2, on the 23rd of June 2013).

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

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

Effect of dexmedetomidine, midazolam, and propofol on lipopolysaccharide-stimulated dendritic cells

Dexmedetomidine, midazolam and propofol are common sedative drugs used in the intensive care unit. Lipopolysaccharides (LPS) are a potent inducer of human dendritic cells (DCs) maturation and survival, which induces cytokine production. The present study aimed to investigate the effect and mechanisms of sedative drugs on LPS-induced cytokine production in DCs. The mouse bone marrow-derived dendritic DC2.4 cell line was used in the present study. The Cell Counting Kit-8 assay was used to measure the viability of cells. Tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, and IL-10 mRNA expression levels and contents were measured using reverse transcription-quantitative polymerase chain reaction and ELISA, respectively. The expression levels of proteins associated with nuclear factor-κB (NF-κB) and mitogen activated protein kinase signaling pathways were assessed by western blotting. The three sedatives had different roles on TNF-α, IL-1β, IL-6, and IL-10 mRNA expression levels and content in DCs. Dexmedetomidine promoted inflammatory cytokine production at high clinical concentrations (10, 1 and 0.1 µM), however suppressed them at the lowest clinical concentration (0.001 µM), which was associated with NF-κB and c-Jun N-terminal kinase (JNK)-mitogen-activated protein kinase (MAPK) signaling. Midazolam inhibited inflammatory cytokine production via suppression of the NF-κB and JNK signaling pathways. Propofol partly inhibited inflammatory cytokine production, including IL-1β and IL-6, and the anti-inflammatory effect may result from inhibition of JNK-MAPK, and enhanced NF-κB and extracellular signal-regulated kinase-MAPK signaling at clinical concentrations. The present study helped to elucidate the function of sedatives in LPS-induced cytokine production in DCs, which will facilitate rational implementation of these sedatives in patients undergoing tracheal intubation with sepsis or multiple organ dysfunction syndrome.

Effects of dexmedetomidine on inflammatory factors, T lymphocyte subsets and expression of NF-κB in peripheral blood mononuclear cells in patients receiving radical surgery of colon carcinoma

The effects of dexmedetomidine on inflammatory factors, T lymphocyte subsets and expression of nuclear factor-κB (NF-κB) in peripheral blood mononuclear cells in patients receiving radical surgery of colon carcinoma were investigated. A total of 141 patients receiving radical surgery of colon carcinoma from January 2014 to April 2017 were divided into two groups randomly. The patients in the treatment group were given dexmedetomidine, while the patients in the control group were treated with saline. Results showed that there were no significant differences in preoperative levels of NF-κB, sICAM-1 and IL-8 between the two groups. However, the above three indexes of the groups were all significantly increased at 0.5 and 24 h after operation, and the results showed that the control group had a higher degree of increase (P<0.05). It was also found that the changes in levels of IL-6 and CRP in patients were the same as those of the above three indexes; in other words, the degree of the increase in the control group was significantly higher than that in the treatment group after operation. Moreover, it was found that there was little difference in the preoperative Ramsay score of patients between the two groups. The scores at 0.5 and 12 h after operation in the treatment group were significantly higher than those in the control group (P<0.05). It was also found that the intraoperative and postoperative dosages of fentanyl in the treatment group were significantly less than those in the control group (P<0.05). We can conclude that the application of dexmedetomidine during anesthesia in patients receiving radical operation of colon carcinoma has a better clinical treatment effect, which can reduce the secretion of inflammatory factors, decrease the inhibition of immunity and reduce the use of fentanyl.

Effects of different methods of anesthesia and analgesia on immune function and serum tumor marker levels in critically ill patients

This study investigated the effects of different anesthesia and analgesia methods on immune function and serum tumor marker levels of critically ill patients undergoing tumor resection surgery. Seventy-six critically ill patients with indications for tumor resection surgery were selected in The Second Affiliated Hospital of Zhengzhou University from September 2015 to August 2016. The patients were randomly divided into a control and an observation group (38 patients each). The patients in the control group were treated with general anesthesia and postoperative intravenous analgesia, while the patients in the observation group were treated with general anesthesia and epidural anesthesia and postoperative epidural analgesia. Venous blood samples were collected at 30 min before anesthesia (T1), 2 h after the beginning of the surgery (T2), immediately after surgery (T3), 24 h after surgery (T4) and 72 h after surgery (T5). The viable cell percentage of T lymphocyte subsets (CD3⁺, CD4⁺, CD8⁺, CD4⁺/CD8⁺) and natural killer (NK) cells were measured by flow cytometry. The levels of carcinoembryonic antigen, sugar chain antigen 199, sugar chain antigen 125, neuron specific enolase and cytokeratin 19 were detected by electrochemiluminescence at 24 h before and after operation. Our results showed the levels of CD3⁺, CD4⁺ and CD4⁺/CD8⁺ in the control group at T3-T5 were significantly lower than those at T1 (p<0.05). The CD3⁺ level in observation group at T3 was also significantly lower than the level at T1 (p<0.05), but it increased at T4 and T5 and showed no significant difference compared with the initial level (p>0.05). The levels of CD4⁺ and CD4⁺/CD8⁺ in the observation group were significantly higher than those in the control group at T2-T5 (p<0.05). And, the levels of CD3⁺ and CD4⁺ were significantly higher than those in the control group at T4 (p<0.05). The level of CD4⁺/CD8⁺ was significantly higher than that in the control group at T5 (p<0.05). No significant differences were found in the levels of CD8⁺ and NK cells between the 2 groups at any of the time-points (p>0.05). No significant differences were found either in any of the tested tumor markers in either group after 24 h. Even without differences on the tumor marker levels, these results suggest that general anesthesia combined with epidural anesthesia and analgesia produces milder deleterious effects on the immune function of perioperative critically ill patients than general anesthesia combined with intravenous analgesia.

Different cellular responses of dexmedetomidine at infected site and peripheral blood of emdotoxemic BALB/c mice

Various sedative agents, including dexmedetomidine (dex), induce immunosuppression, and enhance infection progression. However, there was no information on how anesthetic affects local and systemic cellular immune function. We conducted this study to examine the impact of dex on the differentiation and function of immune cells at site of inflammation and in peripheral blood during endotoxemia of mice. In BALB/c mice with and without endotoxemia, we evaluated the influence of two dosages of 5 and 50 mcg/kg/h intravenous dex on immune cells: including number of T cells (CD3), B cells (CD19), natural killer cells (CD8a), monocytes (CD11b), and macrophages (Mac-3) in peripheral blood, the activities of macrophages in peripheral blood and in peritoneal lavage, and proliferation of B and T cells and of natural killer cells activity in the spleen. Endotoxemia increased the number of CD3 T cells, CD 19 B cells and macrophages in the peripheral blood, augmented macrophage activity in the peritoneum, and increased T cell proliferation and natural killer cell activity in the spleen. Further administration of 5 mcg/kg/h dex attenuated systemic increase in number of T cells, B cells, and macrophages during endotoxemia and 50 mcg/kg/h dex significantly attenuated the increase in activity of macrophages in the peripheral blood during endotoxemia. In the peritoneum, however, 5 mcg/kg/h dex preserved and 50 mcg/kg/h dexmedetomidine enhanced the activity of macrophages during endotoxemia. Increased in proliferation of T cells in spleen during endotoxemia was attenuated by both doses of dex. Last, 50 mcg/kg/h dex enhanced natural killer cells activity during endotoxemia. While preserving the effects of endotoxemia on macrophage's activity in the infection site and natural killer cell's activity in the spleen, dex decreased systemic fulminant immune reaction in endotoxemia, by attenuating the augmented response in the number of T cells, B cells and macrophages, activity of macrophages in the peripheral blood, and proliferation of T cells in spleen during endotoxemia.

Fentanyl inhibits cell viability in human pancreatic cancer cell line and tumor growth in pancreatic cancer cell-transplanted mice

Pancreatic cancer is a kind of devastating disease with a high mortality rate. Fentanyl has been widely applied to anesthesia and analgesia in pancreatic cancer therapy, and is also demonstrated to inhibit the growth of some kinds of cancer cells in existed studies. To investigate the functions of fentanyl in pancreatic cancer, we conducted a series of in vivo and in vitro experiments using human pancreatic cancer cells SW1990 and fentanyl treatment. The cells were transplanted to BALB/c nude mice to generate pancreatic tumor for monitoring tumor growth. Viability, apoptosis, migration and invasion, and cell cycle of SW1990 cells were also analyzed. To reveal the functional mechanisms of fentanyl, the expression changes of factors in these cellular activities were detected. Results showed a significant inhibition of pancreatic tumor growth in the fentanyl-treated group. Fentanyl also inhibited viability of SW1990 cells in vitro. Detailed results showed fentanyl led to promoted cell apoptosis via arresting cells in G0/G1 phase. It also suppressed cell migration and invasion. Further proofs indicated that the factors related to cell apoptosis (Bcl-2, p53 and Caspase-3), cell cycle (p21, Cyclin D1 and CDK4) and epithelial-mesenchymal transition (E-cadherin, Vimentin and α-SMA) showed the corresponding expression changes. Fentanyl might execute its functions via the suppressed MAPK pathways, since the key factors, p38, ERK1/2 and JNK were all down-regulated by fentanyl. This study indicated fentanyl could inhibit viability and growth of pancreatic cancer cells, providing a possible strategy for pancreatic cancer treatment.

Stereoselectivity of isoflurane in adhesion molecule leukocyte function-associated antigen-1

BACKGROUND

Isoflurane in clinical use is a racemate of S- and R-isoflurane. Previous studies have demonstrated that the effects of S-isoflurane on relevant anesthetic targets might be modestly stronger (less than 2-fold) than R-isoflurane. The X-ray crystallographic structure of the immunological target, leukocyte function-associated antigen-1 (LFA-1) with racemic isoflurane suggested that only S-isoflurane bound specifically to this protein. If so, the use of specific isoflurane enantiomers may have advantage in the surgical settings where a wide range of inflammatory responses is expected to occur. Here, we have further tested the hypothesis that isoflurane enantioselectivity is apparent in solution binding and functional studies.

METHODS

First, binding of isoflurane enantiomers to LFA-1 was studied using 1-aminoanthracene (1-AMA) displacement assays. The binding site of each enantiomer on LFA-1 was studied using the docking program GLIDE. Functional studies employed the flow-cytometry based ICAM binding assay.

RESULTS

Both enantiomers decreased 1-AMA fluorescence signal (at 520 nm), indicating that both competed with 1-AMA and bound to the αL I domain. The docking simulation demonstrated that both enantiomers bound to the LFA-1 "lovastatin site." ICAM binding assays showed that S-isoflurane inhibited more potently than R-isoflurane, consistent with the result of 1-AMA competition assay.

CONCLUSIONS

In contrast with the x-ray crystallography, both enantiomers bound to and inhibited LFA-1. S-isoflurane showed slight preference over R-isoflurane.

The antinociceptive effect of dexmedetomidine modulates spleen cell immunity in mice

BACKGROUND

Pain plays roles in both the nervous system and immune system. Changes in the neuroendocrine pathway under pain conditions give rise to sympathetic outflow with increased plasma catecholamines and activate immune reactions. Dexmedetomidine exerts sedative, analgesic, and anesthetic-sparing effects and is known to diminish pro-inflammatory processes by central sympatholytic effects. To investigate the influence of the analgesic effect of dexmedetomidine on immunomodulation under pain conditions, splenic natural killer (NK) tumoricidal cytotoxic activity, proliferative ability of T lymphocytes, and cytokine changes were assessed.

METHODS

After evaluation of the analgesic efficacy of dexmedetomidine in C57BL mice that were subjected to formalin-induced pain, dexmedetomidine (30 µg/kg) or saline was injected intraperitoneally (ip) 30 min before formalin (20 µL of 2% formalin in 0.9% saline) injection. NK cell activity against NK-sensitive YAC-1 lymphoma cells was evaluated by the percentage of specific lactate dehydrogenase (LDH) release. Various numbers of effector cells (NK cells) were added to the wells of a microtiter plate containing 2 × 10(4) target YAC-1 cells in 100 μL, to achieve final effector-to-target cell ratios of 80:1, 40:1, and 20:1. The level of lymphocyte proliferation in response to phytohemagglutinin (PHA) was detected by bromodeoxyuridine (BrdU) incorporation assay. TNF-α, IL-1β, and IL-10 levels were determined in blood samples and supernatants of splenocyte preparations.

RESULTS

IP administration of dexmedetomidine significantly decreased the time of licking and biting during the first and second phases of the formalin test (p <0.001). Formalin-induced pain led to higher activity of NK cells than in sham-treated mice (p <0.05), but NK activity was not increased significantly by ip dexmedetomidine treatment. Formalin-induced pain significantly increased splenic lymphocyte proliferation (p <0.05), but dexmedetomidine did not alter this response. There was a significant increase in plasma TNF-α (p = 0.048) and IL-6 (p = 0.014) levels after formalin-induced pain. However, the differences between the responses after ip dexmedetomidine did not change significantly.

CONCLUSIONS

Dexmedetomidine showed antinociceptive effect on both of acute pain phase 1 and hyperalgesic phase 2 of formalin pain model. Formalin-induced pain alters cellular immunity of spleen in mice. Dexmedetomidine attenuates the activation of NK cells under pain condition, but neither the proliferative response of the splenic lymphocytes nor the cytokine production was affected by dexmedetomidine.

Mechanisms revealed through general anesthetic photolabeling

General anesthetic photolabels are used to reveal molecular targets and molecular binding sites of anesthetic ligands. After identification, the relevance of anesthetic substrates or binding sites can be tested in biological systems. Halothane and photoactive analogs of isoflurane, propofol, etomidate, neurosteroids, anthracene, and long chain alcohols have been used in anesthetic photolabeling experiments. Interrogated protein targets include the nicotinic acetylcholine receptor, GABA_A receptor, tubulin, leukocyte function-associated antigen-1, and protein kinase C. In this review, we summarize insights revealed by photolabeling these targets, as well as general features of anesthetics, such as their propensity to partition to mitochondria and bind voltage-dependent anion channels. The theory of anesthetic photolabel design and the experimental application of photoactive ligands are also discussed.

Propofol shares the binding site with isoflurane and sevoflurane on leukocyte function-associated antigen-1

BACKGROUND

We previously demonstrated that propofol interacted with the leukocyte adhesion molecule leukocyte function-associated antigen-1 (LFA-1) and inhibited the production of interleukin-2 via LFA-1 in a dependent manner. However, the binding site(s) of propofol on LFA-1 remains unknown.

METHODS

First, the inhibition of LFA-1's ligand binding by propofol was confirmed in an enzyme-linked immunosorbent assay (ELISA) ELISA-type assay. The binding site of propofol on LFA-1 was probed with a photolabeling experiment using a photoactivatable propofol analog called azi-propofol-m. The adducted residues of LFA-1 by this compound were determined using liquid chromatography-mass spectrometry. In addition, the binding of propofol to the ligand-binding domain of LFA-1 was examined using 1-aminoanthracene (1-AMA) displacement assay. Furthermore, the binding site(s) of 1-AMA and propofol on LFA-1 was studied using the docking program GLIDE.

RESULTS

We demonstrated that propofol impaired the binding of LFA-1 to its ligand intercellular adhesion molecule-1. The photolabeling experiment demonstrated that the adducted residues were localized in the allosteric cavity of the ligand-binding domain of LFA-1 called "lovastatin site." The shift of fluorescence spectra was observed when 1-AMA was coincubated with the low-affinity conformer of LFA-1 ligand-binding domain (wild-type [WT] αL I domain), not with the high-affinity conformer, suggesting that 1-AMA bound only to WT αL I domain. In the 1-AMA displacement assay, propofol decreased 1-AMA fluorescence signal (at 520 nm), suggesting that propofol competed with 1-AMA and bound to the WT αL I domain. The docking simulation demonstrated that both 1-AMA and propofol bound to the lovastatin site, which agreed with the photolabeling experiment.

CONCLUSIONS

We demonstrated that propofol bound to the lovastatin site in LFA-1. Previously we showed that the volatile anesthetics isoflurane and sevoflurane bound to this site. Taken together, the lovastatin site is an example of the common binding sites for anesthetics currently used clinically.

Propofol participates in gastric mucosal protection through inhibiting the toll-like receptor-4/nuclear factor kappa-B signaling pathway

AIMS

Propofol has demonstrated protective effects against digestive injury. Toll-like receptor-4 (TLR4) is involved in gastric mucosal injury. However, it has not yet been clarified whether propofol protects gastric mucosa from ethanol-induced injury and whether the mechanism involved is related to TLR4 activation. Therefore, this prospective study was carried out to address the issue.

METHODS

Gastric mucosal injury was induced in mice by intragastric administration of ethanol. Propofol was given intraperitoneally 30 min before ethanol intragastric administration and, 1h later, gastric specimens were studied using hematoxylin--eosin staining, quantitative real-time RT-PCR, immunohistochemical staining and Western blot assays; serum specimens were studied using ELISA kits.

RESULTS

Propofol at 25mg/kg significantly attenuated ethanol-induced gastric mucosal injury. In addition, propofol pretreatment significantly inhibited the upregulated expression of high-mobility group box-1 (HMGB1) protein, TLR4 and its downstream signaling molecules--myeloid differentiation factor 88 (MyD88) and nuclear factor kappa-B (NF-κB)--in gastric mucosa, while suppressing the increased release of tumor neurosis factor-α (TNF-α) and interleukin-1β (IL-1β) in serum. Furthermore, upregulation of the Bax/Bcl-2 ratio in gastric mucosa was clearly depressed by propofol.

CONCLUSION

Propofol can inhibit HMGB1 expression and TLR4/MyD88/NF-κB-mediated inflammatory responses, and hamper apoptosis, which may contribute to its protective action against ethanol-induced gastric mucosal injury.