Neuroprotective effects of propofol in acute cerebral injury

The effects of anaesthesia on cell death in a porcine model of neonatal hypoxic-ischaemic brain injury

Background

Hypothermia is neuroprotective after neonatal hypoxic-ischaemic brain injury. However, systemic cooling to hypothermic temperatures is a stressor and may reduce neuroprotection in awake pigs. We compared two experiments of global hypoxic-ischaemic injury in newborn pigs, in which one group received propofol-remifentanil and the other remained awake during post-insult hypothermia treatment.

Methods

In both studies, newborn pigs were anaesthetised using halothane during a 45-min global hypoxic-ischaemic insult induced by reducing Fio2 and graded hypotension until a low-voltage <7 μV electroencephalogram was achieved. On reoxygenation, the pigs were randomly allocated to receive 24 h of normothermia or hypothermia. In the first study (n=18) anaesthesia was discontinued and the pigs' tracheas were extubated. In the second study (n=14) anaesthesia was continued using propofol and remifentanil. Brain injury was assessed after 72 h by classical global histopathology, Purkinje cell count, and apoptotic cell counts in the hippocampus and cerebellum.

Results

Global injury was nearly 10-fold greater in the awake group compared with the anaesthetised group (P=0.021). Hypothermia was neuroprotective in the anaesthetised pigs but not the awake pigs. In the hippocampus, the density of cleaved caspase-3-positive cells was increased in awake compared with anaesthetised pigs in normothermia. In the cerebellum, Purkinje cell density was reduced in the awake pigs irrespective of treatment, and the number of cleaved caspase-3-positive Purkinje cells was greatly increased in hypothermic awake pigs. We detected no difference in cleaved caspase-3 in the granular cell layer or microglial reactivity across the groups.

Conclusions

Our study provides novel insights into the significance of anaesthesia/sedation during hypothermia for achieving optimal neuroprotection.

Comparison of propofol and desflurane for postoperative neurocognitive function in patients with aneurysmal subarachnoid hemorrhage: A prospective randomized trial

Background

Following aneurysmal subarachnoid hemorrhage, 40-50% of survivors experience cognitive dysfunction, which affects their quality of life. Anesthetic agents play a pivotal role in aneurysm surgeries. However, substantial evidence regarding their effects on neurocognitive function is lacking. This study evaluated the effects of propofol and desflurane on postoperative neurocognitive function and serum S-100B levels.

Methods

One hundred patients were equally randomized to receive either propofol (Group P) or desflurane (Group D). Cognitive function was assessed using the Montreal Cognitive Assessment scale at three different time points: Preoperatively, at the time of discharge, and one month after surgery. Perioperative serum levels of S-100B were also measured.

Results

The preoperative mean cognitive score in Group P was 21.64 + 4.46 and in Group D was 21.66 + 4.07 (P = 0.79). At discharge, a significant decrease in cognitive scores was observed compared to preoperative scores (Group P- 20.91 + 3.94, P = 0.03 and Group D-19.28 + 4.22, P = 0.00); however, scores were comparable between the two groups (P = 0.09). One month following surgery, mean cognitive scores were 22.63 + 3.57 in Group P and 20.74 + 3.89 in Group D, and the difference was significant (P = 0.04). Higher memory and orientation scores were observed in Group P than in Group D at one month (P < 0.05) in the subgroup analysis. Both groups had similar serum S-100B levels.

Conclusion

The mean cognitive scores one month after surgery improved significantly with propofol compared with desflurane, but without clinical significance. Individual domain analysis demonstrated that orientation and memory scores were better preserved with propofol.

Sleep loss, caffeine, sleep aids and sedation modify brain abnormalities of mild traumatic brain injury

Little evidence exists about how mild traumatic brain injury (mTBI) is affected by commonly encountered exposures of sleep loss, sleep aids, and caffeine that might be potential therapeutic opportunities. In addition, while propofol sedation is administered in severe TBI, its potential utility in mild TBI is unclear. Each of these exposures is known to have pronounced effects on cerebral metabolism and blood flow and neurochemistry. We hypothesized that they each interact with cerebral metabolic dynamics post-injury and change the subclinical characteristics of mTBI. MTBI in rats was produced by head rotational acceleration injury that mimics the biomechanics of human mTBI. Three mTBIs spaced 48 h apart were used to increase the likelihood that vulnerabilities induced by repeated mTBI would be manifested without clinically relevant structural damage. After the third mTBI, rats were immediately sleep deprived or administered caffeine or suvorexant (an orexin antagonist and sleep aid) for the next 24 h or administered propofol for 5 h. Resting state functional magnetic resonance imaging (rs-fMRI) and diffusion tensor imaging (DTI) were performed 24 h after the third mTBI and again after 30 days to determine changes to the brain mTBI phenotype. Multi-modal analyses on brain regions of interest included measures of functional connectivity and regional homogeneity from rs-fMRI, and mean diffusivity (MD) and fractional anisotropy (FA) from DTI. Each intervention changed the mTBI profile of subclinical effects that presumably underlie healing, compensation, damage, and plasticity. Sleep loss during the acute post-injury period resulted in dramatic changes to functional connectivity. Caffeine, propofol sedation and suvorexant were especially noteworthy for differential effects on microstructure in gray and white matter regions after mTBI. The present results indicate that commonplace exposures and short-term sedation alter the subclinical manifestations of repeated mTBI and therefore likely play roles in symptomatology and vulnerability to damage by repeated mTBI.

Developing a porcine model of severe traumatic brain injury induced by high amplitude rotational acceleration

Introduction

It is unclear which pathophysiological processes initiate and drive dynamic cerebrovascular autoregulation (CA) impairment as seen in traumatic brain injury (TBI). This is not solely attributable to raised intracranial pressure (ICP), but also results from local tissue damage.

Research question

In order to investigate CA disturbing processes, a porcine model is needed that mimics severe TBI as seen in humans. This model requires high amplitude rotational acceleration.

Material and methods

A customized device was built to produce a rotational impulse with high amplitude and short pulse duration. Following preparatory tests on cadaver piglets, six piglets of six weeks old were sedated, ventilated and subjected to rotational impulses of different magnitudes. The impulse was immediately followed by installment of invasive monitoring of ICP, PbO₂, Laser Doppler Flowmetry and arterial blood pressure. TBI was further characterized by magnetic resonance brain imaging.

Results

The current setup enabled to reach sagittal head rotational maximal acceleration magnitudes up to 30 krad/s2. Half of the animals had an increase in ICP, measured shortly after the impulse. It has proved impossible so far to produce a sustained rise in ICP as seen in human severe TBI. MRI showed no anatomical abnormalities which would confirm severe TBI.

Discussion and conclusion

The challenge to build a porcine model in which severe TBI with ICP raise and MRI changes as seen in humans can be reliably reproduced is still ongoing. It might be that higher peak rotational accelerations are needed.

Propofol-Based Anesthesia Maintenance and/or Volatile Anesthetics during Intracranial Aneurysm Repair: A Comparative Analysis of Neurological Outcomes

BACKGROUND

Volatile and intravenous anesthetics have substantial effects on physiological functions, notably influencing neurological function and susceptibility to injury. Despite the importance of the anesthetic approach, data on its relative risks or benefits during surgical clipping or endovascular treatments for unruptured intracranial aneurysms (UIAs) remains scant. We investigated whether using volatile anesthetics alone or in combination with propofol infusion yields superior neurological outcomes following UIA obliteration.

METHODS

We retrospectively reviewed 1001 patients who underwent open or endovascular treatment for UIA, of whom 596 had short- and long-term neurological outcome data (modified Rankin Scale) recorded. Multivariable ordinal regression analysis was performed to examine the association between the anesthetic approach and outcomes.

RESULTS

Of 1001 patients, 765 received volatile anesthetics alone, while 236 received propofol infusion and volatile anesthetics (combined anesthetic group). Short-term neurological outcome data were available for 619 patients and long-term data for 596. No significant correlation was found between the anesthetic approach and neurologic outcomes, irrespective of the type of procedure (open craniotomy or endovascular treatment). The combined anesthetic group had a higher rate of ICU admission (p < 0.001) and longer ICU and hospital length of stay (LOS, p < 0.001). Similarly, a subgroup analysis revealed longer ICU and hospital LOS (p < 0.0001 and p < 0.001, respectively) in patients who underwent endovascular UIA obliteration under a combined anesthetic approach (n = 678).

CONCLUSIONS

The addition of propofol to volatile anesthetics during UIA obliteration does not provide short- or long-term benefits to neurologic outcomes. Compared to volatile anesthetics alone, the combination of propofol and volatile anesthetics may be associated with an increased rate of ICU admission, as well as longer ICU and hospital LOS.

Deep Sedation in Traumatic Brain Injury Patients

Traumatic brain injury (TBI) is one of the leading causes of mortality and disability in adults. In cases of severe TBI, preventing secondary brain injury by managing intracranial hypertension during the acute phase is a critical treatment challenge. Among surgical and medical interventions to control intracranial pressure (ICP), deep sedation can provide comfort to patients and directly control ICP by regulating cerebral metabolism. However, insufficient sedation does not achieve the intended treatment goals, and excessive sedation can lead to fatal sedative-related complications. Therefore, it is important to continuously monitor and titrate sedatives by measuring the appropriate depth of sedation. In this review, we discuss the effectiveness of deep sedation, techniques to monitor the depth of sedation, and the clinical use of recommended sedatives, barbiturates, and propofol in TBI.

Emergency Cricothyrotomy in a Harsh Environment: A Case Report of Complete Airway Obstruction Following a Lightning Strike

A lightning strike is an extreme event with the highest mortality rate among electrical injuries. Death from a lightning strike is caused by either cardiac arrest or respiratory arrest. It is rare for upper airway damage to occur, but in these cases, airway control is recommended. If transoral intubation is unsuccessful, an emergency cricothyrotomy should be considered. Our case report describes an emergency cricothyroidotomy performed in a harsh environment on a mountain 2300 m above sea level on a patient with extensive burns of his supraglottic structures, after being directly hit by a lightning strike.

Neuroprotective Effect of Propolis Polyphenol-Based Nanosheets in Cellular and Animal Models of Rotenone-Induced Parkinson's Disease

Considering the central role of oxidative stress in the onset and progress of Parkinson's diseases (PD), search for compounds with antioxidant properties has attracted a growing body of attention. Here, we compare the neuroprotective effect of bulk and nano forms of the polyphenolic fraction of propolis (PFP) against rotenone-induced cellular and animal models of PD. Mass spectrometric analysis of PFP confirmed the presence of multiple polyphenols including kaempferol, naringenin, coumaric acid, vanillic acid, and ferulic acid. In vitro cellular experiments indicate the improved efficiency of the nano form, compared to the bulk form, of PFP in attenuating rotenone-induced cytotoxicity characterized by a decrease in cell viability, release of lactate dehydrogenase, increased ROS generation, depolarization of the mitochondrial membrane, decreased antioxidant enzyme activity, and apoptosis induction. In vivo experiments revealed that while no significant neuroprotection was observed relating to the bulk form, PFP nanosheets were very effective in protecting animals, as evidenced by the improved behavioral and neurochemical parameters, including decreased lipid peroxidation, increased GSH content, and antioxidant enzyme activity enhancement. We suggest that improved neuroprotective effects of PFP nanosheets may be attributed to their increased water solubility and enrichment with oxygen-containing functional groups (such as OH and COOH), leading to increased antioxidant activity of these compounds.

S100B predicts neurological injury and 30-day mortality following surgery for acute type A aortic dissection: an observational cohort study

BACKGROUND

Neurological injuries are frequent following Acute Type A Aortic Dissection (ATAAD) repair occurring in 4-30% of all patients. Our objective was to study whether S100B can predict neurological injury following ATAAD repair.

METHODS

This was a single-center, retrospective, observational study. The study included all patients that underwent ATAAD repair at our institution between Jan 1998 and Dec 2021 and had recorded S100B-values. The primary outcome measure was neurological injury, defined as focal neurological deficit or coma diagnosed by clinical assessment with or without radiological confirmation and with a symptom duration of more than 24 h. Secondary outcome measure was 30-day mortality.

RESULTS

538 patients underwent surgery during the study period and 393 patients, had recorded S100B-values. The patients had a mean age of 64.4 ± 11.1 years and 34% were female. Receiver operating characteristic curve for S100B 24 h postoperatively yielded area under the curve 0.687 (95% CI 0.615-0.759) and best Youden's index corresponded to S100B 0.225 which gave a sensitivity of 60% and specificity of 75%. Multivariable logistic regression identified S100B ≥ 0.23 μg/l at 24 h as an independent predictor for neurological injury (OR 4.71, 95% CI 2.59-8.57; p < 0.01) along with preoperative cerebral malperfusion (OR 4.23, 95% CI 2.03-8.84; p < 0.01) as well as an independent predictor for 30-day mortality (OR 4.57, 95% CI 1.18-11.70; p < 0.01).

CONCLUSIONS

We demonstrated that S100B, 24 h after surgery is a strong independent predictor for neurological injury and 30-day mortality after ATAAD repair.

TRIAL REGISTRATION

As this was a retrospective observational study it was not registered.

Ozone reduces ischemic damage after a stroke by regulating the autophagy of astrocytes

Background

Stroke is a common and damaging disease of brain tissue, and has high morbidity, disability, and mortality rates. Ozone (O₃) is an isomer of oxygen and can be applied to ozonate the isolated blood in specific containers outside the body and return it to the body. O₃ can also alter the activity and function of multiple cellular components, thus affecting blood viscosity and altering hemodynamics. However, the question of whether O₃ has clinical value in the treatment of stroke requires further investigation. This study sought to evaluate the protective effect and possible mechanism of O₃ in brain injury after stroke.

Methods

First, oxygen-glucose deprivation/reoxygenation (OGD/R)-induced human glioblastoma cell (A172) and middle cerebral artery occlusion (MCAO) rat models were established. Second, the levels of the associated ribonucleic acids and proteins were analyzed using reverse-transcription real-time-quantitative polymerase chain reaction, Western Blot, or immunofluorescence assays. Third, the concentration of glutamate and lactate dehydrogenase (LDH) were assessed using enzyme-linked immunoassays.

Results

The results showed that glial fibrillary acidic protein was upregulated in the OGD/R A172 cells. O₃ decreased LDH and increased glutamate levels in the OGD/R A172 cells, which suggests that O₃ reduced brain damage in the in vitro stroke model. We also showed that O₃ attenuated brain infarction in the in-vivo stroke model. Further, we found that O₃ alleviated stroke-induced brain damage by reducing the apoptosis of astrocytes. Further, the B-cell lymphoma 2 inhibitor propofol alleviated stroke-induced brain damage.

Conclusions

Thus, O₃ notably alleviated stroke-induced brain damage by inhibiting the apoptosis of astrocytes in the OGD/R-induced human glioblastoma cell and MACO rat models.

Comparison of Midazolam and Propofol Infusion to Suppress Stress Response in Patients With Severe TBII: A Prospective, Randomized Controlled Trial

Objective

The stress response following traumatic brain injury (TBI) is a preventable cause of secondary brain injury. This can be prevented using sedation in the intensive care unit (ICU). To date, the choice of sedative agent for preventing stress response is not well-studied in literature.

Methods

This prospective randomized controlled trial included 60 patients with severe TBI admitted to ICU. The patients were randomized into 2 study groups according to the choice of sedation: propofol (group I) and midazolam infusion (group II). The serum cortisol was measured as the primary outcome at admission to ICU and 48 hours following sedation infusion. The baseline Glasgow coma scale, hemodynamic, optic nerve sheath diameter (ONSD), and computed tomography scan findings were noted at admission. Glasgow outcome scale (GOS) was measured as a neurological outcome at discharge from ICU.

Results

There was a statistically significant reduction in serum cortisol level in both the study groups (Δ cortisol, p-value=134.91 (50.5,208.2), 0.00 and 118.8 (42.6,160.4), 0.00, in group I and II, respectively). Serum cortisol levels were comparable among both groups at baseline and 48 hours. Similarly, there was a statistically significant difference in ONSD in both groups, but there was no difference in ONSD value between the groups at 48 hours. The GOS was also similar in both groups at discharge from ICU.

Conclusion

The study demonstrated a similar reduction in serum cortisol levels following 48 hours of propofol or midazolam infusion in patients with severe TBI.

Level of sedation in critically ill adult patients: a protocol for a systematic review with meta-analysis and trial sequential analysis

INTRODUCTION

It is standard of care to provide sedation to critically ill patients to reduce anxiety, discomfort and promote tolerance of mechanical ventilation. Given that sedatives can have differing effects based on a variety of patient and pharmacological characteristics, treatment approaches are largely based on targeting the level of sedation. The benefits of differing levels of sedation must be balanced against potential adverse effects including haemodynamic instability, causing delirium, delaying awakening and prolonging the time of mechanical ventilation and intensive care stay. This systematic review with meta-analysis aims to investigate the current evidence and compare the effects of differing sedation levels in adult critically ill patients.

METHODS AND ANALYSES

We will conduct a systematic review based on searches of preidentified major medical databases (eg, MEDLINE, EMBASE, CENTRAL) and clinical trial registries from their inception onwards to identify trials meeting inclusion criteria. We will include randomised clinical trials comparing any degree of sedation with no sedation and lighter sedation with deeper sedation for critically ill patients admitted to the intensive care unit. We will include aggregate data meta-analyses and trial sequential analyses. Risk of bias will be assessed with domains based on the Cochrane risk of bias tool. An eight-step procedure will be used to assess if the thresholds for clinical significance are crossed, and the certainty of the evidence will be assessed using Grades of Recommendations, Assessment, Development and Evaluation.

ETHICS AND DISSEMINATION

No formal approval or review of ethics is required as individual patient data will not be included. This systematic review has the potential to highlight (1) whether one should believe sedation to be beneficial, harmful or neither in critically ill adults; (2) the existing knowledge gaps and (3) whether the recommendations from guidelines and daily clinical practice are supported by current evidence. These results will be disseminated through publication in a peer-reviewed journal.

Propofol and α2-Agonists Attenuate Microglia Activation and Restore Mitochondrial Function in an In Vitro Model of Microglia Hypoxia/Reoxygenation

Cerebrovascular ischemia is a common clinical disease encompassing a series of complex pathophysiological processes in which oxidative stress plays a major role. The present study aimed to evaluate the effects of Dexmedetomidine, Clonidine, and Propofol in a model of hypoxia/reoxygenation injury. Microglial cells were exposed to 1%hypoxia for 3 h and reoxygenated for 3 h, and oxidative stress was measured by ROS formation and the expression of inflammatory process genes. Mitochondrial dysfunction was assessed by membrane potential maintenance and the levels of various metabolites involved in energetic metabolism. The results showed that Propofol and α2-agonists attenuate the formation of ROS during hypoxia and after reoxygenation. Furthermore, the α2-agonists treatment restored membrane potential to values comparable to the normoxic control and were both more effective than Propofol. At the same time, Propofol, but not α2-agonists, reduces proliferation (Untreated Hypoxia = 1.16 ± 0.2, Untreated 3 h Reoxygenation = 1.28 ± 0.01 vs. Propofol hypoxia = 1.01 ± 0.01 vs. Propofol 3 h Reoxygenation = 1.12 ± 0.03) and microglial migration. Interestingly, all of the treatments reduced inflammatory gene and protein expressions and restored energy metabolism following hypoxia/reoxygenation (ATP content in hypoxia/reoxygenation 3 h: Untreated = 3.11 ± 0.8 vs. Propofol = 7.03 ± 0.4 vs. Dexmedetomidine = 5.44 ± 0.8 vs. Clonidine = 7.70 ± 0.1), showing that the drugs resulted in a different neuroprotective profile. In conclusion, our results may provide clinically relevant insights for neuroprotective strategies in intensive care units.

Safety of general anaesthetics on the developing brain: are we there yet?

Thirty years ago, neurotoxicity induced by general anaesthetics in the developing brain of rodents was observed. In both laboratory-based and clinical studies, many conflicting results have been published over the years, with initial data confirming both histopathological and neurodevelopmental deleterious effects after exposure to general anaesthetics. In more recent years, animal studies using non-human primates and new human cohorts have identified some specific deleterious effects on neurocognition. A clearer pattern of neurotoxicity seems connected to exposure to repeated general anaesthesia. The biochemistry involved in this neurotoxicity has been explored, showing differential effects of anaesthetic drugs between the developing and developed brains. In this narrative review, we start with a comprehensive description of the initial concerning results that led to recommend that any non-essential surgery should be postponed after the age of 3 yr and that research into this subject should be stepped up. We then focus on the neurophysiology of the developing brain under general anaesthesia, explore the biochemistry of the observed neurotoxicity, before summarising the main scientific and clinical reports investigating this issue. We finally discuss the GAS trial, the importance of its results, and some potential limitations that should not undermine their clinical relevance. We finally suggest some key points that could be shared with parents, and a potential research path to investigate the biochemical effects of general anaesthesia, opening up perspectives to understand the neurocognitive effects of repetitive exposures, especially in at-risk children.

Anesthesia with Tricaine Methanesulfonate (MS222) and Propofol and Its Use for Computed Tomography of Red Swamp Crayfish (Procambarus clarkii)

Crayfish (Decapoda: Astacoidea and Parastacoidea) are among the few animals that have stem cells in hemolymph, with the capacity to continuously produce differentiated neuronal structures throughout life. As the use of crayfish and other invertebrates increases in biomedical research, we must develop laboratory standards and guidelines for performing clinical procedures. This manuscript presents introductory protocols for anesthesia in crayfish during diagnostic imaging. Five anesthetic protocols were evaluated: immersion in buffered tricaine methanesulfonate (MS222; 50 mg/L); immersion in buffered MS222 (150 mg/L); immersion in propofol (65 mg/L); injection of propofol (50 mg/kg); and injection of propofol (100 mg/kg) into the ventral surface of an abdominal somite. MS222 immersion (50 and 150 mg/L) had no observable effect on crayfish. After an extended period of time, immersion in propofol (65 mg/L) created a sedative effect suitable for short-term handling. Propofol injection (50 mg/kg) into the ventral surface of an abdominal somite created an effective plane of anesthesia without adverse effects during or after recovery. Propofol injection at 100 mg/kg had adverse effects and is not recommended for use in crayfish. CT imaging was performed successfully as proof of concept for handling anesthetized crayfish. These findings provide initial data for the anesthetization of crayfish used in research settings.

Effect of desflurane on changes in regional cerebral oxygenation in patients undergoing one-lung ventilation is equivalent to the effect of propofol

OBJECTIVES

Desaturation is an important clinical problem during one-lung ventilation (OLV) since it may induce cerebral hypoxia. Measurement of cerebral oxygenation has been shown to provide accurate information about episodes of cerebral hypoxemia. The purpose of this study was to compare the effect of desflurane on changes in cerebral oxygenation during OLV with the effect of propofol.

METHODS

A randomized, single-blinded, prospective study was conducted. Fifty adult patients who were scheduled to undergo thoracic surgery were randomly assigned to anesthetic management using desflurane with remifentanil (Group D: n = 25) or using propofol and remifentanil (Group P: n = 25).

RESULTS

The characteristics of the patients were very similar. Intergroup analysis of changes in cerebral oxygenation showed no significant difference on the operative side (two-way ANOVA, F (7, 368) = 0.425, p = 0.887) or the non-operative side (two-way ANOVA, F (7, 367) = 1.342, p = 0.229). Intragroup analysis of changes in cerebral oxygenation using one-way ANOVA showed no significant difference on the operative side (Group P; p = 0.585, Group D; p = 0.928) or the non-operative side in both groups (Group P; p = 0.657, Group D; p = 0.602).

CONCLUSIONS

The effects of desflurane and propofol on changes in cerebral oxygenation in patients undergoing OLV were equivalent. Our results indicated that desflurane might be an appropriate anesthetic during OLV for maintaining cerebral oxygenation with an effective equivalent to that of propofol.

Propofol Suppresses Microglia Inflammation by Targeting TGM2/NF-κB Signaling

Background

Propofol is a known intravenous hypnotic drug used for induction and maintenance of sedation and general anesthesia. Emerging studies also reveal a neuroprotective effect of propofol in diverse diseases of neuronal injuries via modulating microglia activation. In this study, we aimed to uncover the downstream targets of propofol in this process.

Methods

RNA sequencing analysis to identify genes implicated in the propofol-mediated neuroprotective effect. Quantitative real-time PCR, enzyme-linked immunosorbent assay, and Western blotting analysis were performed to analyze inflammatory gene expression, cytokine levels, and TGM2. BV2 cells and primary microglia were used for functional verification and mechanism studies.

Results

The multifunctional enzyme transglutaminase 2 (TGM2) was identified as a putative functional mediator of propofol. TGM2 was significantly upregulated in lipopolysaccharide- (LPS-) primed BV2 cells. Genetic silencing of TGM2 abolished LPS-induced microglial activation. Notably, gain-of-function experiments showed that the proinflammatory effects of TGM2 were dependent on its GTP binding activity instead of transamidase activity. Then, TGM2 was revealed to activate the NF-κB signaling pathway to facilitate microglial activation. Propofol can inhibit TGM2 expression and NF-κB signaling in BV2 cells and primary microglia. Ectopic expression of TGM2 or constitutively active IKKβ (CA-IKKβ) can compromise propofol-induced anti-inflammatory effects.

Conclusions

Our findings suggest that TGM2-mediated activation of NF-κB signaling is an important mechanism in the propofol-induced neuroprotective effect that prevents microglial activation.

Propofol promotes migration, alleviates inflammation, and apoptosis of lipopolysaccharide-induced human pulmonary microvascular endothelial cells by activating PI3K/AKT signaling pathway via upregulating APOM expression

Propofol (PRO), a clinical potent intravenous anesthetic, plays a significant role in relieving inflammatory diseases by repressing the release of inflammatory cytokines. The present study was aimed to reveal a novel mechanism by which PRO alleviates acute lung injury (ALI). Lipopolysaccharide (LPS) was utilized to induce human pulmonary microvascular endothelial cells (HPMECs) so as to simulate the microenvironment of ALI, and the expression of apolipoprotein M (APOM) was examined with western blotting. Then, APOM was silenced and profopol was used to treat the LPS-injured HPMECs. The cell viability, migration, and apoptosis were respectively observed after the processes of cell counting kit-8, wound healing, transwell, and TUNEL assay. Meanwhile, the inflammatory response was detected by determining the contents of inflammatory cytokines. Subsequently, the relationship between phosphoinositide-3 kinase (PI3K)/protein kinase B (AKT) signaling pathway and PRO was analyzed by western blotting. PI3K/AKT inhibitor LY294002 was employed to evaluate whether the effects of PRO on LPS-challenged HPMECs injury were mediated by this pathway. Results revealed that APOM was notably downregulated in HPMECs after LPS exposure. PRO treatment promoted cell proliferation and migration while alleviated inflammation and apoptosis of LPS-treated HPMECs, which was reversed by APOM-downregulation. PRO brought about the upregulation of proteins in PI3K/AKT signaling pathway, and LY294002 intervention further accentuated the impacts of APOM-knockdown on LPS-challenged HPMECs injury. To conclude, PRO promotes migration and alleviates inflammation and apoptosis of LPS-treated HPMECs by PI3K/AKT signaling pathway via upregulating APOM, which laid an experimental foundation for the future study and clinical application of PRO.

A One-Day Prospective National Observational Study on Sedation-Analgesia of Patients with Brain Injury in French Intensive Care Units: The SEDA-BIP-ICU (Sedation-Analgesia in Brain Injury Patient in ICU) Study

BACKGROUND

Sedation/analgesia is a daily challenge faced by intensivists managing patients with brain injury (BI) in intensive care units (ICUs). The optimization of sedation in patients with BI presents particular challenges. A choice must be made between the potential benefit of a rapid clinical evaluation and the potential exacerbation of intracranial hypertension in patients with impaired cerebral compliance. In the ICU, a pragmatic approach to the use of sedation/analgesia, including the optimal titration, management of multiple drugs, and use of any type of brain monitor, is needed. Our research question was as follows: the aim of the study is to identify what is the current daily practice regarding sedation/analgesia in the management of patients with BI in the ICU in France?

METHODS

This study was composed of two parts. The first part was a descriptive survey of sedation practices and characteristics in 30 French ICUs and 27 academic hospitals specializing in care for patients with BI. This first step validates ICU participation in data collection regarding sedation-analgesia practices. The second part was a 1-day prospective cross-sectional snapshot of all characteristics and prescriptions of patients with BI.

RESULTS

On the study day, among the 246 patients with BI, 106 (43%) had a brain monitoring device and 74 patients (30%) were sedated. Thirty-nine of the sedated patients (53%) suffered from intracranial hypertension, 14 patients (19%) suffered from agitation and delirium, and 7 patients (9%) were sedated because of respiratory failure. Fourteen patients (19%) no longer had a formal indication for sedation. In 60% of the sedated patients, the sedatives were titrated by nurses based on sedation scales. The Richmond Agitation Sedation Scale was used in 80% of the patients, and the Behavioral Pain Scale was used in 92%. The common sedatives and opioids used were midazolam (58.1%), propofol (40.5%), and sufentanil (67.5%). The cerebral monitoring devices available in the participating ICUs were transcranial Doppler ultrasound (100%), intracranial and intraventricular pressure monitoring (93.3%), and brain tissue oxygenation (60%). Cerebral monitoring by one or more monitoring devices was performed in 62% of the sedated patients. This proportion increased to 74% in the subgroup of patients with intracranial hypertension, with multimodal cerebral monitoring in 43.6%. The doses of midazolam and sufentanil were lower in sedated patients managed based on a sedation/analgesia scale.

CONCLUSIONS

Midazolam and sufentanil are frequently used, often in combination, in French ICUs instead of alternative drugs. In our study, cerebral monitoring was performed in more than 60% of the sedated patients, although that proportion is still insufficient. Future efforts should stress the use of multiple monitoring modes and adherence to the indications for sedation to improve care of patients with BI. Our study suggests that the use of sedation and analgesia scales by nurses involved in the management of patients with BI could decrease the dosages of midazolam and sufentanil administered. Updated guidelines are needed for the management of sedation/analgesia in patients with BI.

Brain Herniation and Intracranial Hypertension

This article introduces the basic concepts of intracranial physiology and pressure dynamics. It also includes discussion of signs and symptoms and examination and radiographic findings of patients with acute cerebral herniation as a result of increased as well as decreased intracranial pressure. Current best practices regarding medical and surgical treatments and approaches to management of intracranial hypertension as well as future directions are reviewed. Lastly, there is discussion of some of the implications of critical medical illness (sepsis, liver failure, and renal failure) and treatments thereof on causation or worsening of cerebral edema, intracranial hypertension, and cerebral herniation.

Intracranial Vascular Procedures

Anesthesia for intracranial vascular procedures is complex because it requires a balance of several competing interests and potentially can result in significant morbidity and mortality. Frequently, periods of ischemia, where perfusion must be maintained, are combined with situations that are high risk for hemorrhage. This review discusses the basic surgical approach to several common pathologies (intracranial aneurysms, arteriovenous malformations, and moyamoya disease) along with the goals for anesthetic management and specific high-yield recommendations.

Effects of propofol on hippocampal neuron viability

PURPOSE

In this study, we investigated the effects of different concentration of propofol on cell viability of hippocampal neurons and explored the possible mechanism.

PATIENTS AND METHODS

Primary hippocampal neurons were cultured in vitro and treated with different concentration of propofol. MTT was used to examine the survival of neurons. Flow cytometry was used to detect the neuronal apoptosis. Western-blot analysis was used to examine the expression level of p-p38MAPK and p38MAPK.

RESULTS

We found that low concentration propofol (0.5 μM and 1 μM) promoted the cell survival rate; however, high concentration of propofol (10 μM,50 μM,100 μM,150 μM, and 200 μM) decreased the cell survival rate (P < 0.05). Flow cytometry showed that the neuronal apoptosis rate was decreased in 1 μM propofol group (P < 0.05), but was significantly higher in10μM, 100 μM and 200 μM groups in a concentration-dependent manner (P < 0.05 or P < 0.01). Western blot revealed that the propofol induced the phosphorylation of p38MAPK concentration-dependently and time-dependently. SB203580, one inhibitor of p38MAPK, increased the cell survival rate and decreased the cell apoptosis induced by high concentration of propofol.

CONCLUSION

Low concentration of propofol improved the survival rate of neurons, while high concentration of propofol promoted the cell apoptosis and decreased the cell viability. p38MAPK pathway is involved the effect of high concentration of propofol promoted on primary hippocampal neurons viability and apoptosis.

Is jugular bulb oximetry monitoring associated with outcome in out of hospital cardiac arrest patients?

Cerebral protection against secondary hypoxic-ischemic brain injury is a key priority area in post-resuscitation intensive care management in survivors of cardiac arrest. Nevertheless, the current understanding of the incidence, diagnosis and its’ impact on neurological outcome remains undetermined. The aim of this study was to evaluate jugular bulb oximetry as a potential monitoring modality to detect the incidences of desaturation episodes during post-cardiac arrest intensive care management and to evaluate their subsequent impact on neurological outcome. We conducted a prospective, observational study in unconscious adult patients admitted to the intensive care unit who had successful resuscitation following out of hospital cardiac arrest of presumed cardiac causes. All the patients were treated as per European Resuscitation Council 2015 guidelines and they received jugular bulb catheter. Jugular bulb oximetry measurements were performed at six hourly intervals. The neurological outcomes were evaluated on 90th day after the cardiac arrest by cerebral performance categories scale. Forty patients met the eligibility criteria. Measurements of jugular venous oxygen saturation were performed for 438 times. Altogether, we found 2 incidences of jugular bulb oxygen saturation less than 50% (2/438; 0.46%), and 4 incidences when it was less than 55% (4/438; 0.91%). The study detected an association between SjVO₂ and CO₂ (r = 0.26), each 1 kPa increase in CO₂ led to an increase in SjvO₂ by 3.4% + / − 0.67 (p < 0.0001). There was no association between SjvO₂ and PaO₂ or SjvO₂ and MAP. We observed a statistically significant higher mean SjvO₂ (8.82% + / − 2.05, p < 0.0001) in unfavorable outcome group. The episodes of brain hypoxia detected by jugular bulb oxygen saturation were rare during post-resuscitation intensive care management in out of hospital cardiac arrest patients. Therefore, this modality of monitoring may not yield any additional information towards prevention of secondary hypoxic ischemic brain injury in post cardiac arrest survivors. Other factors contributing towards high jugular venous saturation needs to be considered.

Delayed treatment of propofol inhibits lipopolysaccharide-induced inflammation in microglia through the PI3K/PKB pathway

Propofol is a short-acting intravenous anesthetic agent with potential neuroprotective effect. In this study, we aim to investigate whether delayed propofol treatment is protective against lipopolysaccharide (LPS)-stimulated inflammatory responses in microglial cells. Cultured BV2 microglial cells were exposed to propofol at various time points after initiation of LPS stimulation. Nitrite production and cell viability were assessed after stimulation with LPS for 24 h. The effect of propofol on mRNA levels of cyclooxygenase-2 (Cox-2), interleukin-6 (IL-6), inducible nitric oxide synthase (iNOS), tumor necrosis factor α (TNF-α) and interleukin-1β (IL-1β) was analyzed using reverse transcription PCR (RT-PCR) 6 h after LPS stimulation. The production of TNF-α and reactive oxygen species was also studied. Propofol applied 0–4 h after the initiation of LPS dose-dependently inhibits nitric oxide production. Propofol application also decreased LPS-induced Cox-2, IL-6, iNOS, TNF-α, and IL-1β mRNA expression and induced significant protein kinase B (PKB) phosphorylation in BV2 cells. Treatment with phosphoinositide 3-kinase (PI3K)/PKB inhibitor wortmannin decreased PKB phosphorylation induced by propofol, and abolished the inhibitory effect of propofol on LPS-stimulated NO, reactive oxygen species and TNF-α production. Our results suggest that delayed propofol treatment can reduce LPS-induced activation of microglial cells. These effects may be mediated by activation of the PI3K/PKB pathway.

Successful Management of Massive Air Embolism During Cardiopulmonary Bypass Using Multimodal Neuroprotection Strategies

Complications and critical events during cardiopulmonary bypass (CPB) are very challenging, difficult to manage, and in some instances have the potential to lead to fatal outcomes. Massive cerebral air embolism is undoubtedly a feared complication during CPB. If not diagnosed and managed early, its effects are devastating and even fatal. It is a catastrophic complication and its early diagnosis and intraoperative management are still controversial. This is why the decision-making process during a massive cerebral air embolism represents a challenge for the entire surgical, anesthetic, and perfusion team. All caregivers involved in this event must synchronize their responses quickly, harmoniously, and in such a way that all interventions lead to minimizing the impact of this complication. Its occurrence leaves important lessons to the surgical team that faces it. The best management strategy for a complication of this type is prevention. Nevertheless, a surgical team may ultimately be confronted with such an occurrence at some point despite all the prevention strategies, as was the case with our patient. That is why, in each institution, no effort should be spared to establish cost-effective strategies for early detection and a clear and concise management protocol to guide actions once this complication is detected. It is the duty of each surgical team to determine and clearly organize which strategies will be followed. The purpose of this case study was to demonstrate that a massive air embolism can be rapidly detected using near-infrared spectroscopy monitoring and can be successfully corrected with a multimodal neuroprotection strategy.

Comparison of propofol and desflurane for postanaesthetic morbidity in patients undergoing surgery for aneurysmal SAH: a randomized clinical trial

PURPOSE

Surgery for aneurysmal clipping after subarachnoid haemorrhage (SAH) poses a unique anaesthetic challenge. However, data on the influence of anaesthetic agents in these patients are lacking. The study aims to evaluate the superiority of propofol over desflurane for postanaesthetic morbidity in patients undergoing surgery following aneurysmal SAH.

METHODS

Seventy World Federation of Neurosurgeons Grade I and II patients were randomized into propofol (n = 35) and desflurane groups (n = 35). Anaesthesia was maintained with propofol/fentanyl in propofol group and desflurane/fentanyl in the desflurane group. Jugular venous oxygen saturation (SjVO₂) and brain relaxation were assessed intraoperatively. Time to eye opening, response to verbal commands, and extubation were noted from the time of discontinuing the anaesthetic agent. Duration of postoperative hospital stay and modified Rankin score (MRS) at discharge were subsequently compared.

RESULTS

Median postoperative hospital stay was 9 (6, 14) days with use of propofol and 9 (7, 12) days in desflurane group (P = 0.671). 18 patients in the propofol group and 14 patients in the desflurane group had good outcome (modified Rankin score 0-1; P = 0.453). Both the anaesthetics were similar in terms of intraoperative haemodynamics, brain relaxation, time to eye opening, response to verbal commands, and extubation time (P > 0.05). Emergence hypertension was more in the desflurane group (P = 0.007). The intraoperative SjVO₂ values were significantly higher in the desflurane group (P < 0.05).

CONCLUSION

Propofol and desflurane are comparable in terms of postoperative morbidity in patients undergoing aneurysm neck clipping following SAH.

Does intraperitoneal injection of propofol prior to detorsion improve testes weight and histopathological findings in a rat model?

Objectives

To determine the long-term preventive effects of intraperitoneal propofol on testicular ischemia–reperfusion injury in a rat model.

Materials and methods

Forty adult male albino Wistar rats were divided randomly into the following four groups according to the planned treatment (n=10 per group): group I, control; group II, sham-operated; group III, torsion/detorsion (T/D); and group IV, T/D plus propofol. Testicular ischemia was achieved by twisting the left testis 720° clockwise (ie, applying torsion) for 1 h. In the T/D plus propofol group (group IV), 50 mg/kg propofol was administered intraperitoneally 30 minutes before detorsion. Ipsilateral orchiectomy was performed under general anesthesia to determine the mean testicular weight and to enable histopathological examination of the testes using Johnsen’s mean testicular biopsy score 30 days after the surgical procedure in all groups.

Results

The testicular weights in groups I, II, III, and IV were 1.65±0.32, 1.59±0.33, 1.11±0.56, and 1.08±0.50 g (mean ± SD), respectively. Testicular weight was significantly lower in the T/D groups (III and IV) than in both the control and sham-operated groups (I and II), but there was no improvement in testicular weight as a result of propofol administration. Similarly, Johnsen’s mean testicular biopsy score was lower in groups III and IV than in groups I and II, but no positive effect was conferred by the administration of propofol in group IV.

Conclusion

The use of propofol in the treatment of testicular ischemia–reperfusion injury caused by testis torsion has no significant long-term therapeutic potential.

Analgesia, sedation, and neuromuscular blockade during targeted temperature management after cardiac arrest

The approach to sedation, analgesia, and neuromuscular blockade during targeted temperature management (TTM) remains largely unstudied, forcing clinicians to adapt previous research from other patient environments. During TTM, very little data guide drug selection, doses, and specific therapeutic goals. Sedation should be deep enough to prevent awareness during neuromuscular blockade, but titration is complex as metabolism and clearance are delayed for almost all drugs during hypothermia. Deeper sedation is associated with prolonged intensive care unit (ICU) and ventilator therapy, increased delirium and infection, and delayed wakening which can confound early critical neurological assessments, potentially resulting in erroneous prognostication and inappropriate withdrawal of life support. We review the potential therapeutic goals for sedation, analgesia, and neuromuscular blockade during TTM; the adverse events associated with that treatment; data suggesting that TTM and organ dysfunction impair drug metabolism; and controversies and potential benefits of specific monitoring. We also highlight the areas needing better research to guide our therapy.

Propofol Enhances Hemoglobin-Induced Cytotoxicity in Neurons

BACKGROUND

It has been increasingly suggested that propofol protects against hypoxic-/ischemic-induced neuronal injury. As evidenced by hemorrhage-induced stroke, hemorrhage into the brain may also cause brain damage. Whether propofol protects against hemorrhage-induced brain damage remains unknown. Therefore, in this study, we investigated the effects of propofol on hemoglobin-induced cytotoxicity in cultured mouse cortical neurons.

METHODS

Neurons were prepared from the cortex of embryonic 15-day-old mice. Hemoglobin was used to induce cytotoxicity in the neurons. The neurons were then treated with propofol for 4 hours. Cytotoxicity was determined by lactate dehydrogenase release assay. Caspase-3 activation was examined by Western blot analysis. Finally, the free radical scavenger U83836E was used to examine the potential involvement of oxidative stress in propofol's effects on hemoglobin-induced cytotoxicity.

RESULTS

We found that treatment with hemoglobin induced cytotoxicity in the neurons. Propofol enhanced hemoglobin-induced cytotoxicity. Specifically, there was a significant difference in the amount of lactate dehydrogenase release between hemoglobin plus saline (19.84% ± 5.38%) and hemoglobin plus propofol (35.79% ± 4.41%) in mouse cortical neurons (P = 0.00058, Wilcoxon Mann-Whitney U test, n = 8 in the control group or the treatment group). U83836E did not attenuate the enhancing effects of propofol on hemoglobin-induced cytotoxicity in the neurons, and propofol did not significantly affect caspase-3 activation induced by hemoglobin. These data suggested that caspase-3 activation and oxidative stress might not be the underlying mechanisms by which propofol enhanced hemoglobin-induced cytotoxicity. Moreover, these data suggested that the neuroprotective effects of propofol would be dependent on the condition of the brain injury, which will need to be confirmed in future studies.

CONCLUSIONS

These results from our current proof-of-concept study should promote more research in vitro and in vivo to develop better anesthesia care for patients with hemorrhagic stroke.

Effectiveness of sugammadex for cerebral ischemia/reperfusion injury

Cerebral ischemia may cause permanent brain damage and behavioral dysfunction. The efficacy and mechanisms of pharmacological treatments administered immediately after cerebral damage are not fully known. Sugammadex is a licensed medication. As other cyclodextrins have not passed the necessary phase tests, trade preparations are not available, whereas sugammadex is frequently used in clinical anesthetic practice. Previous studies have not clearly described the effects of the cyclodextrin family on cerebral ischemia/reperfusion (I/R) damage. The aim of this study was to determine whether sugammadex had a neuroprotective effect against transient global cerebral ischemia. Animals were assigned to control, sham-operated, S 16 and S 100 groups. Transient global cerebral ischemia was induced by 10-minute occlusion of the bilateral common carotid artery, followed by 24-hour reperfusion. At the end of the experiment, neurological behavior scoring was performed on the rats, followed by evaluation of histomorphological and biochemical measurements. Sugammadex 16 mg/kg and 100 mg/kg improved neurological outcome, which was associated with reductions in both histological and neurological scores. The hippocampus TUNEL (terminal deoxynucleotidyl transferase dUTP nick end labeling) and caspase results in the S 16 and S 100 treatment groups were significantly lower than those of the I/R group. Neurological scores in the treated groups were significantly higher than those of the I/R group. The study showed that treatment with 16 mg/kg and 100 mg/kg sugammadex had a neuroprotective effect in a transient global cerebral I/R rat model. However, 100 mg/kg sugammadex was more neuroprotective in rats.

Effect of propofol and remifentanil on cerebral perfusion and oxygenation in pigs: a systematic review

The objective of this review is to evaluate the existing literature with regard to the influence of propofol and remifentanil total intravenous anaesthesia (TIVA) on cerebral perfusion and oxygenation in healthy pigs. Anaesthesia has influence on cerebral haemodynamics and it is important not only in human but also in veterinary anaesthesia to preserve optimal regulation of cerebral haemodynamics. Propofol and remifentanil are widely used in neuroanaesthesia and are increasingly used in experimental animal studies. In translational models, the pig has advantages compared to small laboratory animals because of brain anatomy, metabolism, neurophysiological maturation, and cerebral haemodynamics. However, reported effects of propofol and remifentanil on cerebral perfusion and oxygenation in pigs have not been reviewed. An electronic search identified 99 articles in English. Title and abstract screening selected 29 articles for full-text evaluation of which 19 were excluded with reasons. Of the 10 peer-reviewed articles included for review, only three had propofol or remifentanil anaesthesia as the primary study objective and only two directly investigated the effect of anaesthesia on cerebral perfusion and oxygenation (CPO). The evidence evaluated in this systematic review is limited, not focused on propofol and remifentanil and possibly influenced by factors of potential importance for CPO assessment. In one study of healthy pigs, CPO measures were within normal ranges following propofol-remifentanil anaesthesia, and addition of a single remifentanil bolus did not affect regional cerebral oxygen saturation (rSO2). Even though the pool of evidence suggests that propofol and remifentanil alone or in combination have limited effects on CPO in healthy pigs, confirmative evidence is lacking.

Optimizing sedation in patients with acute brain injury

Daily interruption of sedative therapy and limitation of deep sedation have been shown in several randomized trials to reduce the duration of mechanical ventilation and hospital length of stay, and to improve the outcome of critically ill patients. However, patients with severe acute brain injury (ABI; including subjects with coma after traumatic brain injury, ischaemic/haemorrhagic stroke, cardiac arrest, status epilepticus) were excluded from these studies. Therefore, whether the new paradigm of minimal sedation can be translated to the neuro-ICU (NICU) is unclear. In patients with ABI, sedation has ‘general’ indications (control of anxiety, pain, discomfort, agitation, facilitation of mechanical ventilation) and ‘neuro-specific’ indications (reduction of cerebral metabolic demand, improved brain tolerance to ischaemia). Sedation also is an essential therapeutic component of intracranial pressure therapy, targeted temperature management and seizure control. Given the lack of large trials which have evaluated clinically relevant endpoints, sedative selection depends on the effect of each agent on cerebral and systemic haemodynamics. Titration and withdrawal of sedation in the NICU setting has to be balanced between the risk that interrupting sedation might exacerbate brain injury (e.g. intracranial pressure elevation) and the potential benefits of enhanced neurological function and reduced complications. In this review, we provide a concise summary of cerebral physiologic effects of sedatives and analgesics, the advantages/disadvantages of each agent, the comparative effects of standard sedatives (propofol and midazolam) and the emerging role of alternative drugs (ketamine). We suggest a pragmatic approach for the use of sedation-analgesia in the NICU, focusing on some practical aspects, including optimal titration and management of sedation withdrawal according to ABI severity.

Neuroanesthesia

Neuroanesthesia is a subspecialty area of anesthesia that deals with the complex relationships of anesthetic medications, neurosurgical procedures, and the critical care issues that surround the management of these patients. In this chapter we will focus on a brief overview of the key features associated with the management of patients undergoing neurosurgical procedures, including a review of hemodynamic/neurologic effects of anesthetic agents, neurophysiologic monitoring, and unique medical complications associated with these procedures. For successful patient outcomes, multidisciplinary approaches and effective team communications are essential in these high-intensity environments. This chapter should serve as an introduction to the multitude of issues that face the anesthesiologist and surgeon when dealing with this patient population.

Propofol Limits Microglial Activation after Experimental Brain Trauma through Inhibition of Nicotinamide Adenine Dinucleotide Phosphate Oxidase

Background:

Microglial activation is implicated in delayed tissue damage after traumatic brain injury (TBI). Activation of microglia causes up-regulation of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, with the release of reactive oxygen species and cytotoxicity. Propofol appears to have antiinflammatory actions. The authors evaluated the neuroprotective effects of propofol after TBI and examined in vivo and in vitro whether such actions reflected modulation of NADPH oxidase.

Methods:

Adult male rats were subjected to moderate lateral fluid percussion TBI. Effect of propofol on brain microglial activation and functional recovery was assessed up to 28 days postinjury. By using primary microglial and BV2 cell cultures, the authors examined propofol modulation of lipopolysaccharide and interferon-γ–induced microglial reactivity and neurotoxicity.

Results:

Propofol improved cognitive recovery after TBI in novel object recognition test (48 ± 6% for propofol [n = 15] vs. 30 ± 4% for isoflurane [n = 14]; P = 0.005). The functional improvement with propofol was associated with limited microglial activation and decreased cortical lesion volume and neuronal loss. Propofol also attenuated lipopolysaccharide- and interferon-γ–induced microglial activation in vitro, with reduced expression of inducible nitric oxide synthase, nitric oxide, tumor necrosis factor-α, interlukin-1β, reactive oxygen species, and NADPH oxidase. Microglial-induced neurotoxicity in vitro was also markedly reduced by propofol. The protective effect of propofol was attenuated when the NADPH oxidase subunit p22phox was knocked down by small interfering RNA. Moreover, propofol reduced the expression of p22phox and gp91phox, two key components of NADPH oxidase, after TBI.

Conclusion:

The neuroprotective effects of propofol after TBI appear to be mediated, in part, through the inhibition of NADPH oxidase.

A Cerebral Recovery Index (CRI) for early prognosis in patients after cardiac arrest

Introduction

Electroencephalogram (EEG) monitoring in patients treated with therapeutic hypothermia after cardiac arrest may assist in early outcome prediction. Quantitative EEG (qEEG) analysis can reduce the time needed to review long-term EEG and makes the analysis more objective. In this study, we evaluated the predictive value of qEEG analysis for neurologic outcome in postanoxic patients.

Methods

In total, 109 patients admitted to the ICU for therapeutic hypothermia after cardiac arrest were included, divided over a training and a test set. Continuous EEG was recorded during the first 5 days or until ICU discharge. Neurologic outcomes were based on the best achieved Cerebral Performance Category (CPC) score within 6 months. Of the training set, 27 of 56 patients (48%) and 26 of 53 patients (49%) of the test set achieved good outcome (CPC 1 to 2). In all patients, a 5 minute epoch was selected each hour, and five qEEG features were extracted. We introduced the Cerebral Recovery Index (CRI), which combines these features into a single number.

Results

At 24 hours after cardiac arrest, a CRI <0.29 was always associated with poor neurologic outcome, with a sensitivity of 0.55 (95% confidence interval (CI): 0.32 to 0.76) at a specificity of 1.00 (CI, 0.86 to 1.00) in the test set. This results in a positive predictive value (PPV) of 1.00 (CI, 0.73 to 1.00) and a negative predictive value (NPV) of 0.71 (CI, 0.53 to 0.85). At the same time, a CRI >0.69 predicted good outcome, with a sensitivity of 0.25 (CI, 0.10 to 0.14) at a specificity of 1.00 (CI, 0.85 to 1.00) in the test set, and a corresponding NPV of 1.00 (CI, 0.54 to 1.00) and a PPV of 0.55 (CI, 0.38 to 0.70).

Conclusions

We introduced a combination of qEEG measures expressed in a single number, the CRI, which can assist in prediction of both poor and good outcomes in postanoxic patients, within 24 hours after cardiac arrest.

Synergistic activation of lipopolysaccharide-stimulated glial cells by propofol

Despite the extensive use of propofol in general anesthetic procedures, the effects of propofol on glial cell were not completely understood. In lipopolysaccharide (LPS)-stimulated rat primary astrocytes and BV2 microglial cell lines, co-treatment of propofol synergistically induced inflammatory activation as evidenced by the increased production of NO, ROS and expression of iNOS, MMP-9 and several cytokines. Propofol augmented the activation of JNK and p38 MAPKs induced by LPS and the synergistic activation of glial cells by propofol was prevented by pretreatment of JNK and p38 inhibitors. When we treated BV2 cell culture supernatants treated with LPS plus propofol on cultured rat primary neuron, it induced a significant neuronal cell death. The results suggest that the repeated use of propofol in immunologically challenged situation may induce glial activation in brain.

Does propofol prevent testicular ischemia-reperfusion injury due to torsion in the long term?

OBJECTIVES

Our aim was to investigate the long-term preventive effect of propofol on testicular ischemia-reperfusion injury in a rat model.

METHODS

Twenty-four adult male Sprague-Dawley rats were randomly divided into four groups (n = 6 for each group), control, sham-operated, torsion/detorsion (T/D) and T/D + propofol. Testicular ischemia was achieved by twisting the left testis 720° clockwise for 2 h. Half an hour before detorsion, 50 mg/kg propofol was given intraperitoneally to the T/D + propofol group. Ipsilateral orchiectomies to determine mean testicular weights and histopathological examination according to Johnsen's mean testicular biopsy score criteria were performed 30 days after surgical procedure in all groups.

RESULTS

Mean testicular weights were 1.57 ± 0.12 g in group I, 1.59 ± 0.36 g in group II, 0.84 ± 0.20 g in group III and 0.87 ± 0.29 g in group IV. Mean testicular weights decreased significantly in the T/D groups, but no improvement in testicular weight was observed with propofol administration (p 0.9372). Similarly, the Johnsen's mean testicular biopsy scores of the T/D groups were lower than those of the control and sham-operated groups, but no positive effect was determined with the administration of propofol in the T/D groups (p 0.1797).

CONCLUSIONS

Our results showed that there is no apparent long-term therapeutic potential attendant on using propofol in the treatment of testicular ischemia-reperfusion injury caused by testis torsion.

Midazolam suppresses interleukin-1β-induced interleukin-6 release from rat glial cells

Background

Peripheral-type benzodiazepine receptor (PBR) expression levels are low in normal human brain, but their levels increase in inflammation, brain injury, neurodegenerative states and gliomas. It has been reported that PBR functions as an immunomodulator. The mechanisms of action of midazolam, a benzodiazepine, in the immune system in the CNS remain to be fully elucidated. We previously reported that interleukin (IL)-1β stimulates IL-6 synthesis from rat C6 glioma cells and that IL-1β induces phosphorylation of inhibitory kappa B (IκB), p38 mitogen-activated protein (MAP) kinase, stress-activated protein kinase (SAPK)/c-Jun N-terminal kinase (JNK), extracellular signal-regulated kinase 1/2, and signal transducer and activator of transcription (STAT)3. It has been shown that p38 MAP kinase is involved in IL-1β-induced IL-6 release from these cells. In the present study, we investigated the effect of midazolam on IL-1β-induced IL-6 release from C6 cells, and the mechanisms of this effect.

Methods

Cultured C6 cells were stimulated by IL-1β. IL-6 release from C6 cells was measured using an enzyme-linked immunosorbent assay, and phosphorylation of IκB, the MAP kinase superfamily, and STAT3 was analyzed by Western blotting.

Results

Midazolam, but not propofol, inhibited IL-1β-stimulated IL-6 release from C6 cells. The IL-1β-stimulated levels of IL-6 were suppressed by wedelolactone (an inhibitor of IκB kinase), SP600125 (an inhibitor of SAPK/JNK), and JAK inhibitor I (an inhibitor of JAK 1, 2 and 3). However, IL-6 levels were not affected by PD98059 (an inhibitor of MEK1/2). Midazolam markedly suppressed IL-1β-stimulated STAT3 phosphorylation without affecting the phosphorylation of p38 MAP kinase, SAPK/JNK or IκB.

Conclusion

These results strongly suggest that midazolam inhibits IL-1β-induced IL-6 release in rat C6 glioma cells via suppression of STAT3 activation. Midazolam may affect immune system function in the CNS.

Effects of propofol on proliferation and anti-apoptosis of neuroblastoma SH-SY5Y cell line: new insights into neuroprotection

Recently, it has been suggested that anesthetic agents may have neuroprotective potency. The notion that anesthetic agents can offer neuroprotection remains controversial. Propofol, which is a short-acting intravenous anesthetic agent, may have potential as a neuroprotective agent. In this study, we tried to determine whether propofol affected the viability of human neuroblastoma SH-SY5Y cells by using the MTT assay. Surprisingly, our results showed that propofol at a dose of 1-10 μM could improve cell proliferation. However, at higher doses (200 μM), propofol appears to be cytotoxic. On the other hand, propofol could up-regulate the expression of key proteins involved in neuroprotection including B-cell lymphoma 2 at a dose range of 1-10 μM, activation of phospho-serine/threonine protein kinase at a dose range of 0.5-10 μM, and activation of phospho-extracellular signal-regulated kinases at a dose range of 5-10 μM. Similarly, we demonstrate that propofol (10 μM) could elevate protein levels of heat shock protein 90 and heat shock protein 70. Therefore, we choose to utilize a 10 μM concentration of propofol to assess neuroprotective activities in our studies. In the following experiments, we used dynorphin A to generate cytotoxic effects on SH-SY5Y cells. Our data indicate that propofol (10 μM) could inhibit the cytotoxicity in SH-SY5Y cells induced by dynorphin A. Furthermore, propofol (10 μM) could decrease the expression of the p-P38 protein as well. These data together suggest that propofol may have the potential to act as a neuroprotective agent against various neurologic diseases. However, further delineation of the precise neuroprotective effects of propofol will need to be examined.

N-acetylcysteine improves hemodynamics and reduces oxidative stress in the brains of newborn piglets with hypoxia-reoxygenation injury

Reactive oxygen species have been implicated in the pathogenesis of hypoxic-ischemic injury. It has been shown previously that treating an animal with N-acetyl-L-cysteine (NAC), a scavenger of free radicals, significantly minimizes hypoxic-ischemic-induced brain injury in various acute models. Using a subacute swine model of neonatal hypoxia-reoxygenation (H-R), we evaluated the long-term beneficial effect of NAC against oxidative stress-induced brain injury. Newborn piglets were randomly assigned to a sham-operated group (without H-R, n = 6), and two H-R experimental groups (n = 8 each), with 2 h normocapnic alveolar hypoxia and 1 h of 100% oxygen reoxygenation followed by 21% oxygen for 47 h. Five minutes after reoxygenation, the H-R piglets received either normal saline (H-R controls) or NAC (150 mg/kg bolus and 20 mg/kg/h IV for 24 h) in a blinded randomized fashion. Treating the piglets with NAC significantly increased both common carotid arterial flow (CCAF) and oxygen delivery during the early phase of rexoygenation, while both CCAF and carotid oxygen delivery of the H-R group remained lower than the sham-operated groups throughout the experimental period. Compared with H-R controls, significantly higher amounts of anesthetic and sedative medications were required to maintain the NAC-treated piglets in stable condition throughout the experimental period, indicating a stronger recovery. Post-resuscitation NAC treatment also significantly attenuated the increase in cortical caspase-3 and lipid hydroperoxide concentrations. Our findings suggest that post-resuscitation administration of NAC reduces cerebral oxidative stress with improved cerebral oxygen delivery, and probably attenuates apoptosis in newborn piglets with H-R insults.

Anaesthetic-related neuroprotection: intravenous or inhalational agents?

In designing the anaesthetic plan for patients undergoing surgery, the choice of anaesthetic agent may often appear irrelevant and the best results obtained by the use of a technique or a drug with which the anaesthesia care provider is familiar. Nevertheless, in those surgical procedures (cardiopulmonary bypass, carotid surgery and cerebral aneurysm surgery) and clinical situations (subarachnoid haemorrhage, stroke, brain trauma and post-cardiac arrest resuscitation) where protecting the CNS is a priority, the choice of anaesthetic drug assumes a fundamental role. Treating patients with a neuroprotective agent may be a consideration in improving overall neurological outcome. Therefore, a clear understanding of the relative degree of protection provided by various agents becomes essential in deciding on the most appropriate anaesthetic treatment geared to these objectives. This article surveys the current literature on the effects of the most commonly used anaesthetic drugs (volatile and gaseous inhalation, and intravenous agents) with regard to their role in neuroprotection. A systematic search was performed in the MEDLINE, Cumulative Index to Nursing and Allied Health Literature (CINHAL®) and Cochrane Library databases using the following keywords: 'brain' (with the limits 'newborn' or 'infant' or 'child' or 'neonate' or 'neonatal' or 'animals') AND 'neurodegeneration' or 'apoptosis' or 'toxicity' or 'neuroprotection' in combination with individual drug names ('halothane', 'isoflurane', 'desflurane', 'sevoflurane', 'nitrous oxide', 'xenon', 'barbiturates', 'thiopental', 'propofol', 'ketamine'). Over 600 abstracts for articles published from January 1980 to April 2010, including studies in animals, humans and in vitro, were examined, but just over 100 of them were considered and reviewed for quality. Taken as a whole, the available data appear to indicate that anaesthetic drugs such as barbiturates, propofol, xenon and most volatile anaesthetics (halothane, isoflurane, desflurane, sevoflurane) show neuroprotective effects that protect cerebral tissue from adverse events--such as apoptosis, degeneration, inflammation and energy failure--caused by chronic neurodegenerative diseases, ischaemia, stroke or nervous system trauma. Nevertheless, in several studies, the administration of gaseous, volatile and intravenous anaesthetics (especially isoflurane and ketamine) was also associated with dose-dependent and exposure time-dependent neurodegenerative effects in the developing animal brain. At present, available experimental data do not support the selection of any one anaesthetic agent over the others. Furthermore, the relative benefit of one anaesthetic versus another, with regard to neuroprotective potential, is unlikely to form a rational basis for choice. Each drug has some undesirable adverse effects that, together with the patient's medical and surgical history, appear to be decisive in choosing the most suitable anaesthetic agent for a specific situation. Moreover, it is important to highlight that many of the studies in the literature have been conducted in animals or in vitro; hence, results and conclusions of most of them may not be directly applied to the clinical setting. For these reasons, and given the serious implications for public health, we believe that further investigation--geared mainly to clarifying the complex interactions between anaesthetic drug actions and specific mechanisms involved in brain injury, within a setting as close as possible to the clinical situation--is imperative.

Cerebral pial vascular changes under propofol or sevoflurane anesthesia during global cerebral ischemia and reperfusion in rabbits

BACKGROUND

Propofol and sevoflurane are commonly used anesthetics for neurosurgery. The aim of the study was to compare the effects of propofol with sevoflurane on cerebral pial arteriolar and venular diameters during global brain ischemia and reperfusion.

METHODS

Japanese white rabbits were anesthetized with propofol (n=11), sevoflurane (n=9), or the combination of sevoflurane and intralipid (n=10). Global brain ischemia was induced by clamping the brachiocephalic, left common carotid, and left subclavian arteries for 15 minutes. Pial microcirculation was observed microscopically through closed cranial windows and measured using a digital-video analyzer. Measurements were recorded before clamping and afterward for 120 minutes.

RESULTS

Plasma glucose and mean arterial blood pressure increased significantly during ischemia in the propofol-anesthetized rabbits. During ischemia, pial arteriolar and venular diameters decreased significantly in all groups. After unclamping, large and small, pial arteriolar and venular diameters increased temporarily and significant dilation was observed in both sevoflurane groups. From 10 minutes after unclamping until the end of the study, large and small arterioles returned to baseline diameters in the sevoflurane groups, but decreased significantly by 10% to 20% in the propofol rabbits. Ischemia-induced adverse effects such as pulmonary edema and acute brain swelling were observed primarily in propofol-anesthetized rabbits.

CONCLUSION

Propofol and sevoflurane acted differently on pial vessels during reperfusion after ischemic insult. Pial arterioles and venules did not dilate immediately after reperfusion, and subsequently constricted throughout the reperfusion period in propofol-anesthetized rabbits. In contrast, pial arterioles and venules dilated temporarily and returned to baseline in sevoflurane-anesthetized rabbits.

Acute management of acquired brain injury part II: an evidence-based review of pharmacological interventions

PRIMARY OBJECTIVE

To review the research literature on pharmacological interventions used in the acute phase of acquired brain injury (ABI) to manage ICP and improve neural recovery.

MAIN OUTCOMES

A literature search of multiple databases (CINAHL, EMBASE, MEDLINE and PSYCHINFO) and hand searched articles covering the years 1980-2008 was performed. Peer reviewed articles were assessed for methodological quality using the PEDro scoring system for randomized controlled trials (RCTs) and the Downs and Black tool for RCTs and non-randomized trials. Levels of evidence were assigned and recommendations were made.

RESULTS

In total, 11 pharmacological interventions used in the acute management of ABI were evaluated. These included propofol, barbiturates, opioids, midazolam, mannitol, hypertonic saline, corticosteroids, progesterone, bradykinin antagonists, dimethyl sulphoxide and cannabinoids. Of these interventions, corticosteroids were found to be contraindicated and cannabinoids were reported as ineffective. The other nine interventions demonstrated some benefit for treatment of acute ABI. However, rarely did these benefits result in improved long-term patient outcomes.

CONCLUSIONS

Substantial research has been devoted to evaluating the use of pharmacological interventions in the acute management of ABI. However, much of this research has focused on the application of individual interventions in small single-site trials. Future research will need to establish larger patient samples to evaluate the benefits of combined interventions within specific patient populations.