Effects of propofol on pulmonary inflammatory response and dysfunction induced by cardiopulmonary bypass*

Propofol improves survival in a murine model of sepsis via inhibiting Rab5a-mediated intracellular trafficking of TLR4

BACKGROUND

Propofol is a widely used anesthetic and sedative, which has been reported to exert an anti-inflammatory effect. TLR4 plays a critical role in coordinating the immuno-inflammatory response during sepsis. Whether propofol can act as an immunomodulator through regulating TLR4 is still unclear. Given its potential as a sepsis therapy, we investigated the mechanisms underlying the immunomodulatory activity of propofol.

METHODS

The effects of propofol on TLR4 and Rab5a (a master regulator involved in intracellular trafficking of immune factors) were investigated in macrophage (from Rab5a-/- and WT mice) following treatment with lipopolysaccharide (LPS) or cecal ligation and puncture (CLP) in vitro and in vivo, and peripheral blood monocyte from sepsis patients and healthy volunteers.

RESULTS

We showed that propofol reduced membrane TLR4 expression on macrophages in vitro and in vivo. Rab5a participated in TLR4 intracellular trafficking and both Rab5a expression and the interaction between Rab5a and TLR4 were inhibited by propofol. We also showed Rab5a upregulation in peripheral blood monocytes of septic patients, accompanied by increased TLR4 expression on the cell surface. Propofol downregulated the expression of Rab5a and TLR4 in these cells.

CONCLUSIONS

We demonstrated that Rab5a regulates intracellular trafficking of TLR4 and that propofol reduces membrane TLR4 expression on macrophages by targeting Rab5a. Our study not only reveals a novel mechanism for the immunomodulatory effect of propofol but also indicates that Rab5a may be a potential therapeutic target against sepsis.

Effects of driving pressure-guided ventilation by individualized positive end-expiratory pressure on oxygenation undergoing robot-assisted laparoscopic radical prostatectomy: a randomized controlled clinical trial

PURPOSE

Patients with robot-assisted laparoscopic radical prostatectomy (RALP) need to be placed in Trendelenburg position, which results in cranial displacement of the diaphragm and decreases functional residual capacity and pulmonary compliance. Positive end-expiratory pressure (PEEP) can increase ventilation in the dorsal area, reduce the occurrence of atelectasis and improve oxygenation. However, due to individual differences, inappropriate PEEP will cause lung injury and even hemodynamic instability. Therefore, our study is to evaluate the efficacy of individualized PEEP in RALP.

METHODS

We randomly recruited 48 patients and divided them into driving pressure-guided individualized PEEP group (P group, individualized PEEP) or traditional lung-protective ventilation strategy group (C group, tidal volume 8 mL/kg combined with PEEP of 5cmH2O). The primary outcome was the PaO2/FiO2 before extubation. The secondary outcomes included individualized PEEP values in the P group, the results of arterial blood gas analysis, respiratory mechanics parameters and vital sign parameters. Other measurements included intraoperative vasoactive drug dosage, length of stay, postoperative SpO2, leukocyte count, temperature, serum inflammatory factors and soluble receptor for advanced glycation end products (sRAGE).

RESULTS

Individualized PEEP improved the PaO2/FiO2 before extubation (P = 0.034) and decreased driving pressure (P = 0.011). The PEEP valued in the P group was 14 [10-14] cmH2O. The lung compliance of the P group was significantly higher than that in the C group (P = 0.013). There was no significant difference in other measurements.

CONCLUSIONS

Individualized PEEP could improve PaO2/FiO2 in patients who underwent RALP and do not increase the dosage of intraoperative vasoactive drug and the release of inflammatory factors.

TRIAL REGISTRATION

www.chictr.org.cn (registration no. ChiCTR2100047271).

Effects of interventions targeting the systemic inflammatory response to cardiac surgery on clinical outcomes in adults

BACKGROUND

Organ injury is a common and severe complication of cardiac surgery that contributes to the majority of deaths. There are no effective treatment or prevention strategies. It has been suggested that innate immune system activation may have a causal role in organ injury. A wide range of organ protection interventions targeting the innate immune response have been evaluated in randomised controlled trials (RCTs) in adult cardiac surgery patients, with inconsistent results in terms of effectiveness.

OBJECTIVES

The aim of the review was to summarise the results of RCTs of organ protection interventions targeting the innate immune response in adult cardiac surgery. The review considered whether the interventions had a treatment effect on inflammation, important clinical outcomes, or both.

SEARCH METHODS

CENTRAL, MEDLINE, Embase, conference proceedings and two trial registers were searched on October 2022 together with reference checking to identify additional studies.

SELECTION CRITERIA

RCTs comparing organ protection interventions targeting the innate immune response versus placebo or no treatment in adult patients undergoing cardiac surgery where the treatment effect on innate immune activation and on clinical outcomes of interest were reported.

DATA COLLECTION AND ANALYSIS

Searches, study selection, quality assessment, and data extractions were performed independently by pairs of authors. The primary inflammation outcomes were peak IL-6 and IL-8 concentrations in blood post-surgery. The primary clinical outcome was in-hospital or 30-day mortality. Treatment effects were expressed as risk ratios (RR) and standardised mean difference (SMD) with 95% confidence intervals (CI). Meta-analyses were performed using random effects models, and heterogeneity was assessed using I2.

MAIN RESULTS

A total of 40,255 participants from 328 RCTs were included in the synthesis. The effects of treatments on IL-6 (SMD -0.77, 95% CI -0.97 to -0.58, I2 = 92%) and IL-8 (SMD -0.92, 95% CI -1.20 to -0.65, I2 = 91%) were unclear due to heterogeneity. Heterogeneity for inflammation outcomes persisted across multiple sensitivity and moderator analyses. The pooled treatment effect for in-hospital or 30-day mortality was RR 0.78, 95% CI 0.68 to 0.91, I2 = 0%, suggesting a significant clinical benefit. There was little or no treatment effect on mortality when analyses were restricted to studies at low risk of bias. Post hoc analyses failed to demonstrate consistent treatment effects on inflammation and clinical outcomes. Levels of certainty for pooled treatment effects on the primary outcomes were very low.

AUTHORS' CONCLUSIONS

A systematic review of RCTs of organ protection interventions targeting innate immune system activation did not resolve uncertainty as to the effectiveness of these treatments, or the role of innate immunity in organ injury following cardiac surgery.

Anesthetic care influences long-term outcomes: What is the evidence?

Despite advances in cancer therapy surgery remains one of the most important treatments for solid tumors; however, even with the development of better and less invasive surgical techniques, surgery is characterized by the increased risk of tumor metastasis, accelerated growth of pre-existing micrometastasis and cancer recurrence. Total intravenous anesthesia (TIVA) and regional anesthesia have been proposed to improve long-term outcomes after cancer surgery by different mechanisms, including attenuation of the neuroendocrine response, immunosuppression, decreased opioid requirements (opioids promote angiogenesis and tumor growth) and avoidance of volatile inhalational agents. Much of the data that support these ideas originate from laboratory studies, while there is no clear consensus from the retrospective cohort studies to date. Several randomized controlled trials (RCTs) are in progress and may provide a better understanding regarding the role of the anesthesiologist in cancer surgery. The purpose of this review is to summarize the experimental and human data regarding the effect of anesthesia agents and anesthesia techniques on cancer outcomes.

Papaverine Perfusion via the Aortic Root before Heart Re-beating Alleviates Myocardial Injury after Heart Valve Replacement

AIM

Myocardial injury is inevitable during cardiac surgical procedures and reducing myocardial injury in patients with CPB surgery is the focus of current research. Papaverine is accepted as an ideal coronary vasodilator. This study was to estimate the effect of papaverine perfusion via the aortic root before heart re-beating on patients undergoing heart valve replacement.

METHODS

All the patients enrolled in this study were admitted during 2013-2015. The basic clinical characteristics of the patients preoperative, intraoperative, and postoperative were compared. The immunochemistry assays and enzyme-linked immunosorbent assay (ELISA) were performed to assess the serum biomarkers. Western blot and immunohistochemistry (IHC) were undertaken to detect the expression of associated proteins.

RESULTS

Patients receiving papaverine perfusion via the aortic root before heart re-beating during heart valve replacement surgery under CPB showed less extracorporeal circulation time and CPB time, higher automatic heartbeat recovery rate, less mechanical ventilation time, shorter ICU and in-hospital stay, less leak of cTnI and CK-MB, and weaker inflammatory response than the patients in control group. In addition, the protein expression of IL-6/8/10 and TNF-α was reduced by the perfusion of papaverine. The IHC staining for NFκB was depressed in papaverine group.

CONCLUSION

Papaverine perfusion presented positive effect during valve replacement; this cardioprotective effect may be associated with inhibition of inflammatory response and NF-κB. These findings provided new clues for reduction of myocardial injury during cardiac surgery.

Effects of intraoperative propofol-based total intravenous anesthesia on postoperative pain in spine surgery: Comparison with desflurane anesthesia - a randomised trial

BACKGROUND

As reported, patients experience less postoperative pain after propofol-based total intravenous anesthesia (TIVA). In the present study, we investigated the postoperative analgesic effects between propofol-based TIVA and desflurane anesthesia after spine surgery.

METHODS

Sixty patients were included who received (surgical time >180 minutes) lumbar spine surgery. Patients were randomly assigned to receive either TIVA (with target-controlled infusion) with propofol/fentanyl-based anesthesia (TIVA group) or desflurane/fentanyl-based anesthesia (DES group), titrated to maintain Bispectral Index values between 45 and 55. All patients received patient-controlled analgesia (PCA) with fentanyl for postoperative pain relief. Numeric pain rating scale (NRS) pain scores, postoperative fentanyl consumption, postoperative rescue tramadol use, and fentanyl-related side effects were recorded.

RESULTS

The TIVA group patients reported lower NRS pain scores during coughing on postoperative day 1 but not day 2 and 3 (P = .002, P = .133, P = .161, respectively). Less fentanyl consumption was observed on postoperative days 1 and 2, but not on day 3 (375 μg vs 485 μg, P = .032, 414 μg vs 572 μg, P = .033, and 421 μg vs 479 μg, P = .209, respectively), less cumulative fentanyl consumption at postoperative 48 hours (790 μg vs 1057 μg, P = .004) and 72 hours (1210 μg vs 1536 μg, P = .004), and total fentanyl consumption (1393 μg vs 1704 μg, P = .007) when compared with the DES group. No difference was found in rescue tramadol use and fentanyl-related side effects.

CONCLUSION

Patients anesthetized with propofol-based TIVA reported less pain during coughing and consumed less daily and total PCA fentanyl after lumbar spine surgery.

Propofol inhibits endogenous formyl peptide-induced neutrophil activation and alleviates lung injury

Critically ill patients have a high risk of sepsis. Various studies have demonstrated that propofol has anti-inflammatory effects that may benefit critically ill patients who require anesthesia. However, the mechanism and therapeutic effect remain incompletely understood. Our previous data suggest that propofol can act as a formyl peptide receptor 1 (FPR1) antagonist. Here, we hypothesize that propofol mitigates sepsis-induced acute lung injury (ALI) by inhibiting mitochondria-derived N-formyl peptide-mediated neutrophil activation. Oxidative stress caused by activated neutrophils is involved in the pathogenesis of ALI. In human neutrophils, propofol competitively reduced the release of superoxide and associated reactive oxygen species induced by fMMYALF, a human mitochondria-derived N-formyl peptide, suggesting that propofol effectively suppresses neutrophilic oxidative stress. In addition, propofol significantly inhibited fMMYALF-induced elastase release, chemotaxis, calcium mobilization, and phosphorylation of protein kinase B and mitogen-activated protein kinases. These results indicate that propofol suppresses neutrophil activation by blocking the interaction between endogenous N-formyl peptide and its receptor, FPR1, thus inhibiting downstream signaling. Furthermore, propofol alleviated alveolar wall disruption, edematous changes, and neutrophil infiltration in lipopolysaccharide-induced ALI in mice. Noticeably, propofol improved the survival of sepsis mice. This study indicates that the anti-neutrophil effects of propofol may benefit critically ill septic patients.

MicroRNA‑214 suppresses propofol‑induced neuroapoptosis through activation of phosphoinositide 3‑kinase/protein kinase B signaling by targeting phosphatase and tensin homolog expression

The present study aimed to investigate the effects of microRNA (miR)‑214 on neuroapoptosis induced by propofol and the possible mechanism of its anti‑apoptotic effects. Initially, it was observed that miR‑214 expression was upregulated in propofol‑induced neuroapoptosis rats. Next, propofol‑treated nerve cells were transfected with miR‑214 mimics. The results revealed that miR‑214 overexpression induced apoptosis, inhibited cell proliferation, inhibited cyclin D1 protein expression, promoted caspase‑3 activity and B‑cell lymphoma 2‑associated X protein expression, and enhanced the levels of inflammation factors in nerve cells treated with propofol. In addition, miR‑214 overexpression suppressed phosphoinositide 3‑kinase/protein kinase B (PI3K/Akt) signaling by targeting the activation of phosphatase and tensin homolog (PTEN) and nuclear factor‑κB expression in nerve cells treated with propofol. Treatment with a PTEN inhibitor successfully suppressed the PTEN protein expression and decreased the apoptosis of propofol‑treated nerve cells subsequent to miR‑214 overexpression through PI3K/Akt signaling. In conclusion, the present study data revealed that miR‑214 suppressed propofol‑induced neuroapoptosis through the activation of PI3K/Akt signaling by targeting PTEN expression.

Comparison of the expression of cluster of differentiation (CD)39 and CD73 between propofol- and sevoflurane-based anaesthesia during open heart surgery

High expression of cluster of differentiation (CD)39 and CD73 has cardio-protective effects. We hypothesised that the expression of CD39 and CD73 would differ between propofol- and volatile anaesthetic-based anaesthesia in patients undergoing open heart surgery (OHS). The objective of this prospective randomized trial was to compare the changes in CD39 and CD73 levels in CD4+ T cells between propofol- and sevoflurane-based anaesthesia during OHS. The study randomly allocated 156 patients undergoing OHS to a propofol or sevoflurane group. Blood was obtained preoperatively and up to 48 hours after weaning from cardiopulmonary bypass (CPB). The expression levels of CD39 and CD73 in circulating CD4+ T cells, serum cytokines and other laboratory parameters were analysed. The primary outcome was the expression of CD39 and CD73 on CD4+ T cells. Demographic data and perioperative haemodynamic changes did not show significant differences between the two groups. The expression of CD39 and CD73 in the sevoflurane group was significantly lower than in the propofol group (P < 0.001). Other laboratory findings including cardiac enzymes and cytokine levels, did not show significant intergroup differences. Propofol attenuated the decrease in CD39 and CD73 in circulating CD4+ T cells compared to sevoflurane-based anaesthesia during OHS.

Lipid peroxidation in cardiac surgery: towards consensus on biomonitoring, diagnostic tools and therapeutic implementation

This review focuses on oxidative stress and more specifically lipid peroxidation in cardiac surgery, one of the fundamental theories of perioperative complications. We present the molecular pathways leading to lipid peroxidation and integrate analytical methods that allow detection of lipid peroxidation markers in the fluid phase with those focusing on volatile compounds in exhaled breath. In order to explore the accumulated data in the literature, we present a systematic review of quantitative analysis of malondialdehyde, a widely used lipid peroxidation product at various stages of cardiac surgery. This exploration reveals major limitations of existing studies in terms of variability of reported values and significant gaps due to discrete and variable sampling times during surgery. We also appraise methodologies that allow real-time and continuous monitoring of oxidative stress. Complimentary techniques highlight that beyond the widely acclaimed contribution of the cardiopulmonary bypass technology and myocardial reperfusion injury, the use of diathermy contributes significantly to intraoperative lipid peroxidation. We conclude that there is an urgent need to implement the theory of oxidative stress towards a paradigm change in the clinical practice. Firstly, we need to acquire definite and irrefutable information on the link between lipid peroxidation and post-operative complications by building international consensus on best analytical approaches towards generating qualitatively and quantitatively comparable datasets in coordinated multicentre studies. Secondly, we should move away from routine low-risk surgeries towards higher risk interventions where there is major unmet clinical need for improving patient journey and outcomes. There is also need for consensus on best therapeutic interventions which could be tested in convincing large scale clinical trials. As future directions, we propose combination of fluid phase platforms and 'metabography', an extended form of capnography-including real-time analysis of lipid peroxidation and volatile footprints of metabolism-for better patient phenotyping prior to and during high risk surgery towards molecular prediction, stratification and monitoring of the patient's journey.

Comparison of the myocardial protective effect of sevoflurane versus propofol in patients undergoing heart valve replacement surgery with cardiopulmonary bypass

BACKGROUND

This study aimed to compare myocardial protective effects of anaesthesia with intravenous infusion of propofol versus inhalation of sevoflurane in patients undergoing heart valve replacement surgery with cardiopulmonary bypass.

METHODS

Seventy-six patients undergoing valve replacement with cardiopulmonary bypass were randomly assigned to propofol or sevoflurane anesthesia during the surgery, respectively. For assessing myocardial injury, cardiac troponin I (cTnI) and creatine kinase isozyme (CK-MB) were determined before induction (T₀), 0.5 h (T₁) and 3 h (T₂) after aortic unclamping, and 24 h (T₃) and 48 h (T₄) after surgery. The concentrations of interleukin (IL)-6 and IL-10 as the systemic inflammatory and anti-inflammatory markers were also measured at above time points.

RESULTS

In the sevoflurane group, the plasma concentrations of cTnI and CK-MB from T_l to T₄ and the levels of IL-6 and IL-10 from T₁ to T₂ were lower than those in the propofol group. Moreover, a higher ratio of automatic heart beat recovery and a shorter length of intensive care unit or hospital stay were found in the sevoflurane group comparing with the propofol group.

CONCLUSION

Sevoflurane anaesthesia produced more prominent myocardial protection and attenuated inflammatory response than propofol anaesthesia in patients with valve replacement surgery under cardiopulmonary bypass, resulting in shorter ICU and in-hospital stay.

RETROSPECTIVE CLINICAL TRIAL REGISTRATION

Identified as ChiCTR-IOR-16009979 at http://www.chictr.org.cn/ .

The Effects of Short-Term Propofol and Dexmedetomidine on Lung Mechanics, Histology, and Biological Markers in Experimental Obesity

BACKGROUND

Administering anesthetics to the obese population requires caution because of a variety of reasons including possible interactions with the inflammatory process observed in obese patients. Propofol and dexmedetomidine have protective effects on pulmonary function and are widely used in short- and long-term sedation, particularly in intensive care unit settings in lean and obese subjects. However, the functional and biological effects of these drugs in obesity require further elucidation. In a model of diet-induced obesity, we compared the short-term effects of dexmedetomidine versus propofol on lung mechanics and histology, as well as biological markers of inflammation and oxidative stress modulation in obesity.

METHODS

Wistar rats (n = 56) were randomly fed a standard diet (lean) or experimental diet (obese) for 12 weeks. After this period, obese animals received sodium thiopental intraperitoneally and were randomly allocated into 4 subgroups: (1) nonventilated (n = 4) for molecular biology analysis only (control); (2) sodium thiopental (n = 8); (3) propofol (n = 8); and (4) dexmedetomidine (n = 8), which received continuous IV administration of the corresponding agents and were mechanically ventilated (tidal volume = 6 mL/kg body weight, fraction of inspired oxygen = 0.4, positive end-expiratory pressure = 3 cm H2O) for 1 hour.

RESULTS

Compared with lean animals, obese rats did not present increased body weight but had higher total body and trunk fat percentages, airway resistance, and interleukin-6 levels in the lung tissue (P = 0.02, P = 0.0027, and P = 0.01, respectively). In obese rats, propofol, but not dexmedetomidine, yielded increased airway resistance, bronchoconstriction index (P = 0.016, P = 0.02, respectively), tumor necrosis factor-α, and interleukin-6 levels, as well as lower levels of nuclear factor-erythroid 2-related factor-2 and glutathione peroxidase (P = 0.001, Bonferroni-corrected t test).

CONCLUSIONS

In this model of diet-induced obesity, a 1-hour propofol infusion yielded increased airway resistance, atelectasis, and lung inflammation, with depletion of antioxidative enzymes. However, unlike sodium thiopental and propofol, short-term infusion of dexmedetomidine had no impact on lung morphofunctional and biological variables.

Effects of Intra-Operative Total Intravenous Anaesthesia with Propofol versus Inhalational Anaesthesia with Sevoflurane on Post-Operative Pain in Liver Surgery: A Retrospective Case-Control Study

Background

Patients receiving total intravenous anesthesia (TIVA) with propofol have been shown to experience less postoperative pain. We evaluated the post-operative analgesic effects of propofol compared with sevoflurane maintenance of anesthesia in liver surgery. This study was registered at ClinicalTrials.gov (NCT02179437).

Methods

In this retrospective study, records of patients who underwent liver surgery between 2010 and 2013 were reviewed. Ninety-five patients anesthetized with propofol TIVA were matched with 95 patients anesthetized with sevoflurane. Numeric pain rating scale (NRS) pain scores, postoperative morphine consumption, side effects and patients’ satisfaction with pain relief were evaluated.

Results

The TIVA group reported lower NRS pain scores during coughing on postoperative days 1 and 2 but not 3 (p = 0.0127, p = 0.0472, p = 0.4556 respectively). They also consumed significantly less daily (p = 0.001 on day 1, p = 0.0231 on day 2, p = 0.0004 on day 3), accumulative (p = 0.001 on day 1, p<0.0001 on day 2 and p = 0.0064 on day 3) and total morphine (p = 0.03) when compared with the sevoflurane group. There were no differences in total duration of intravenous patient controlled analgesia (PCA) morphine use and patient satisfaction. No difference was found in reported side effects.

Conclusion

Patients anesthetized with propofol TIVA reported less pain during coughing and consumed less daily, accumulative and total morphine after liver surgery.

Propofol increases morbidity and mortality in a rat model of sepsis

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Propofol protects against focal cerebral ischemia via inhibition of microglia-mediated proinflammatory cytokines in a rat model of experimental stroke

Ischemic stroke induces microglial activation and release of proinflammatory cytokines, contributing to the expansion of brain injury and poor clinical outcome. Propofol has been shown to ameliorate neuronal injury in a number of experimental studies, but the precise mechanisms involved in its neuroprotective effects remain unclear. We tested the hypothesis that propofol confers neuroprotection against focal ischemia by inhibiting microglia-mediated inflammatory response in a rat model of ischemic stroke. Sprague-Dawley rats were subjected to middle cerebral artery occlusion (MCAO) for 2 h followed by 24 h of reperfusion. Propofol (50 mg/kg/h) or vehicle was infused intravenously at the onset of reperfusion for 30 minutes. In vehicle-treated rats, MCAO resulted in significant cerebral infarction, higher neurological deficit scores and decreased time on the rotarod compared with sham-operated rats. Propofol treatment reduced infarct volume and improved the neurological functions. In addition, molecular studies demonstrated that mRNA expression of microglial marker Cd68 and Emr1 was significantly increased, and mRNA and protein expressions of proinflammatory cytokines tumor necrosis factor-α, interleukin-1β and interleukin-6 were augmented in the peri-infarct cortical regions of vehicle-treated rats 24 h after MCAO. Immunohistochemical study revealed that number of total microglia and proportion of activated microglia in the peri-infarct cortical regions were markedly elevated. All of these findings were ameliorated in propofol-treated rats. Furthermore, vehicle-treated rats had higher plasma levels of interleukin-6 and C-reactive protein 24 h after MCAO, which were decreased after treatment with propofol. These results suggest that propofol protects against focal cerebral ischemia via inhibition of microglia-mediated proinflammatory cytokines. Propofol may be a promising therapeutic agent for the treatment of ischemic stroke and other neurodegenerative diseases associated with microglial activation.

Effects of sevoflurane and propofol on the inflammatory response and pulmonary function of perioperative patients with one-lung ventilation

This study compared the effects of sevoflurane and propofol on the inflammatory response and pulmonary function of patients with lung cancer during the perioperative period. Forty patients who underwent a selective resection of the inferior lobe of the left lung were randomly divided into two groups, with one group anesthetized with sevoflurane and the other with propofol (groups S and P, respectively). Radial arterial and mixed venous blood were extracted for blood gas analysis, in order to calculate the alveolar-arterial oxygen partial pressure difference (PA-aDO₂), respiratory index (RI) and pulmonary shunt ratio (Qs/Qt) prior to the induction of anesthesia (T₀), prior to one-lung ventilation (OLV) (T₁), 1 h subsequent to the commencement of OLV (T₂), 1 h following restoration of two-lung ventilation (T₃), 2 h following restoration of two-lung ventilation (T₄) and 24 h post-surgery (T₅). In addition, blood was extracted from the radial artery at T₀, T₁, T₂, T₃, T₄ and T₅ in order to detect the presence of tumor necrosis factor-α (TNF-α), IL-6 and IL-10 in the blood serum. Between T₁ and T_4, the tidal volume, airway plateau pressure and end-expiratory positive airway pressure were recorded, in order to calculate the lung dynamic compliance (Cdyn). Heart rate, mean arterial pressure, central venous pressure, cardiac output and the duration of OLV (OLV-T) were recorded at T_0–5. Compared with T0, the levels of TNF-α, IL-6 and IL-10 significantly increased during T₂ to T₄ in both groups (P<0.05). PA-aDO₂ and RI increased during T₁ to T₄, and Qs/Qt increased at T₂ (P<0.05). Compared with T₁, Cdyn decreased during T₂ to T₄ in the S group, whereas Cdyn was reduced at T₂ in the P group (P<0.05). Compared with the P group, TNF-α level increased and IL-10 decreased at T₃ and T₄ in the S group. PA-aDO₂ and RI increased, but Cdyn decreased at T₂ and T₃ in the S group. Qs/Qt increased at T₂ in the S group. The results of the present study demonstrated that, in comparison with propofol, sevoflurane exhibited an enhanced capacity to aggravate injury to pulmonary function during the perioperative stages. This occurred via the release of inflammatory factors, the aggravation of lung edema and the inhibition of hypoxic pulmonary vasoconstriction.

Propofol inhibits superoxide production, elastase release, and chemotaxis in formyl peptide-activated human neutrophils by blocking formyl peptide receptor 1

Neutrophils play a critical role in acute and chronic inflammatory processes, including myocardial ischemia/reperfusion injury, sepsis, and adult respiratory distress syndrome. Binding of formyl peptide receptor 1 (FPR1) by N-formyl peptides can activate neutrophils and may represent a new therapeutic target in either sterile or septic inflammation. Propofol, a widely used i.v. anesthetic, has been shown to modulate immunoinflammatory responses. However, the mechanism of propofol remains to be established. In this study, we showed that propofol significantly reduced superoxide generation, elastase release, and chemotaxis in human neutrophils activated by fMLF. Propofol did not alter superoxide generation or elastase release in a cell-free system. Neither inhibitors of γ-aminobutyric acid receptors nor an inhibitor of protein kinase A reversed the inhibitory effects of propofol. In addition, propofol showed less inhibitory effects in non-FPR1-induced cell responses. The signaling pathways downstream from FPR1, involving calcium, AKT, and ERK1/2, were also competitively inhibited by propofol. These results show that propofol selectively and competitively inhibits the FPR1-induced human neutrophil activation. Consistent with the hypothesis, propofol inhibited the binding of N-formyl-Nle-Leu-Phe-Nle-Tyr-Lys-fluorescein, a fluorescent analog of fMLF, to FPR1 in human neutrophils, differentiated THP-1 cells, and FPR1-transfected human embryonic kidney-293 cells. To our knowledge, our results identify, for the first time, a novel anti-inflammatory mechanism of propofol by competitively blocking FPR1 in human neutrophils. Considering the importance of N-formyl peptides in inflammatory processes, our data indicate that propofol may have therapeutic potential to attenuate neutrophil-mediated inflammatory diseases by blocking FPR1.

Immunological modifications induced from products used during the perioperative period

Anesthetics and other products used during the perioperative period may influence immune function not only merely by reducing the HPA-axis stress response but also by directly modulating innate and adaptive immune responses. Most of the literature on the immune effects of anesthetics has been derived from in vitro or animal studies, due to the number of confounding variables in real life surgical settings. These immunosuppressive effects might not normally have clinical consequences for an immune-competent patient, but may act as important modifiers in postoperative morbidity and mortality. Furthermore, some inhibitory effects on neutrophil functions may provide a therapeutically beneficial effect under specific surgical clinical conditions, such as ischemia-reperfusion injury.

Protective effect of propofol and its relation to postoperation recovery in children undergoing cardiac surgery with cardiopulmonary bypass

The aim of this study was to investigate the effect of propofol and its relation to postoperation recovery in children undergoing cardiac surgery with cardiopulmonary bypass (CPB). Twenty ASA class I-II children with congenital heart disease undergoing cardiac surgery were randomly allocated to a propofol group (n = 10) or a control group (n = 10). Blood samples were collected at five time points: before operation (T (0)), before the start of CPB (T (1)), 25 min after the aorta was cross-clamped (T (2)), 30 min after release of the aortic cross-clamp (T (3)), and 2 h after the cessation of CPB (T (4)). The myocardial samples were collected at the time of incubation into the right atrium before CPB and at 30 min after reperfusion. After CPB, propofol significantly suppressed the increase of the serum lactate dehydrogenase (LDH), creatine phosphokinase (CK), and interleukin-6 (IL-6) levels and the decrease of the serum superoxide dismutase (SOD) level. In addition, propofol inhibited the increase of myocardial nuclear factor-κB (NF-κB) expression and inflammatory cells infiltration after CPB. Furthermore, propofol significantly shortened the tracheal extubation time. In conclusion, propofol exerts a protective effect and improves postoperation recovery through its antioxidant and anti-inflammatory actions in children undergoing cardiac surgery with CPB.

Comparison of the effects of propofol and midazolam on inflammation and oxidase stress in children with congenital heart disease undergoing cardiac surgery

PURPOSE

To investigate and compare the effects of propofol and midazolam on inflammation and oxidase stress in children with congenital heart disease undergoing cardiac surgery.

MATERIALS AND METHODS

Thirty-two ASA class I-II children with congenital heart disease undergoing cardiac surgery were randomly divided into two groups: propofol combined with low dose fentanyl (PF group, n = 16) and midazolam combined with low dose fentanyl (MF group, n = 16). Tracheal extubation time and length of Intensive Care Unit (ICU) stay were recorded. Blood samples were taken before operation (T₀), at 2 h after release of the aorta cross-clamp (T₃) and at 24 h after operation (T₄) to measure interleukin 6 (IL-6), IL-8, superoxide dismutase (SOD) and malondialdehyde (MDA) levels. Myocardium samples were collected at 10-20 min after aorta cross-clamp (T₁) and at 10-20 min after the release of the aorta cross-clamp (T₂) to detect heme oxygenase-1 (HO-1) expression.

RESULTS

Tracheal extubation time and length of ICU stay in PF group were significantly shorter than those of the MF group (p < 0.05, respectively). After cardiopulmonary bypass, IL-6, IL-8 and MDA levels were significantly increased, and the SOD level was significantly reduced in both two groups, but PF group exhibited lower IL-6, IL-8 and MDA levels and higher SOD levels than the MF group (p < 0.05, respectively). The HO-1 expression in the PF group was significantly higher than that in MF group at the corresponding time points (p < 0.05, respectively).

CONCLUSION

Propofol is superior to midazolam in reducing inflammation and oxidase stress and in improving post-operation recovery in children with congenital heart disease undergoing cardiac surgery.