Lasting effects of general anesthetics on the brain in the young and elderly: "mixed picture" of neurotoxicity, neuroprotection and cognitive impairment

General anesthetic agents induce neurotoxicity through oligodendrocytes in the developing brain

General anesthetic agents can impact brain function through interactions with neurons and their effects on glial cells. Oligodendrocytes perform essential roles in the central nervous system, including myelin sheath formation, axonal metabolism, and neuroplasticity regulation. They are particularly vulnerable to the effects of general anesthetic agents resulting in impaired proliferation, differentiation, and apoptosis. Neurologists are increasingly interested in the effects of general anesthetic agents on oligodendrocytes. These agents not only act on the surface receptors of oligodendrocytes to elicit neuroinflammation through modulation of signaling pathways, but also disrupt metabolic processes and alter the expression of genes involved in oligodendrocyte development and function. In this review, we summarize the effects of general anesthetic agents on oligodendrocytes. We anticipate that future research will continue to explore these effects and develop strategies to decrease the incidence of adverse reactions associated with the use of general anesthetic agents.

Impact of anesthetics on rat hippocampus and neocortex: A comprehensive proteomic study based on label-free mass spectrometry

Anesthesia is regarded as an important milestone in medicine. However, the negative effect on memory and learning has been observed. In addition, the impact of anesthetics on postoperative cognitive functions is still discussed. In this work, in vivo experiment simulating a general anesthesia and ICU sedation was designed to assess the impact of two intravenous (midazolam, dexmedetomidine) and two inhalational (isoflurane, desflurane) agents on neuronal centers for cognition (neocortex), learning, and memory (hippocampus). More than 3600 proteins were quantified across both neocortex and hippocampus. Proteomic study revealed relatively mild effects of anesthetics, nevertheless, protein dysregulation uncovered possible different effect of isoflurane (and midazolam) compared to desflurane (and dexmedetomidine) to neocortical and hippocampal proteins. Isoflurane induced the upregulation of hippocampal NMDAR and other proteins of postsynaptic density and downregulation of GABA signaling, whereas desflurane and dexmedetomidine rather targeted mitochondrial VDAC isoforms and protein regulating apoptotic activity.

Endovascular treatment of brain aneurysms under conscious sedation: a systematic review of procedural feasibility and safety

Over the last decades, minimally invasive techniques have revolutionized the endovascular treatment (EVT) of brain aneurysms. In parallel, the development of conscious sedation (CS), a potentially less harmful anesthetic protocol than general anesthesia (GA), has led to the course optimization of surgeries, patient outcomes, and healthcare costs. Nevertheless, the feasibility and safety of EVT of brain aneurysms under CS have yet to be assessed thoroughly. Herein, we systematically reviewed the medical literature about this procedure. In accordance with the PRISMA guidelines, four databases (PubMed, EMBASE, SCOPUS, and Cochrane Library) were queried to identify articles describing the EVT of brain aneurysms under CS. Successful procedural completion, complete aneurysm occlusion outcomes, intraoperative complications, clinical outcomes, and mortality rates assessed the feasibility and safety. Our search strategy yielded 567 records, of which 11 articles were included in the qualitative synthesis. These studies entailed a total of 1142 patients (40.7% females), 1183 intracranial aneurysms (78.4% in the anterior circulation and 60.9% unruptured at presentation), and 1391 endovascular procedures (91.9% performed under CS). EVT modalities under CS included coiling alone (63.2%), flow diversion (17.7%), stent-assisted coiling (10.6%), stenting alone (6.5%), onyx embolization alone (1.7%), onyx + stenting (0.2%), and onyx + coiling (0.2%). CS was achieved by combining two or more anesthetics, such as midazolam, fentanyl, and remifentanil. Selection criteria for CS were heterogenous and included patients' history of pulmonary and cardiovascular diseases, outweighing the benefits of CS versus GA, a Hunt and Hess score of I-II, a median score of 3 in the American Society of Anesthesiology scale, and patient's compliance with elective CS. Procedures were deemed successful or achieving complete aneurysm occlusion in 88.1% and 9.4% of reported cases, respectively. Good clinical outcomes were described in 90.4% of patients with available data at follow-up (mean time: 10.7 months). The procedural complication rate was 16%, and the mortality rate was 2.8%. No complications or mortality were explicitly attributed to CS. On the other hand, procedure abortion and conversion from CS to GA were deemed necessary in 5% and 1% of cases, respectively. The present study highlights the feasibility of performing EVT of brain aneurysms under CS as an alternative anesthetic protocol to GA. However, the limited nature of observational studies, methodological quality, the predominant absence of a comparative GA group, and clinical data during follow-up restrict a conclusive statement about the safety of EVT under CS. Accordingly, further research endeavors are warranted toward a higher level of evidence that can be translated into surgical practice.

Engeletin ameliorates sevoflurane-induced cognitive impairment by activating PPAR-gamma in neonatal mice

Sevoflurane (SEV) is a commonly used anesthetic in pediatric surgery. Recent studies reported that repeated use of SEV contributes to cognitive impairment. Engeletin has been discovered to exert anti-inflammatory effects in various diseases. However, the detailed roles and mechanisms of engeletin in SEV-induced cognitive dysfunction of neonatal mice remain unclear. In this study, C57BL/6 neonatal mice were randomly divided into Ctrl, SEV, SEV + Engeletin (10 mg /kg), SEV + Engeletin (20 mg/kg), and SEV + Engeletin (40 mg/kg) groups. The Morris water maze (MWM) test suggested that engeletin treatment significantly improved SEV-induced cognitive impairment in neonatal mice. Employing ELISA and Nissl staining analysis, engeletin reduced neuroinflammation and loss of nerve cells caused by SEV, respectively. The treatment of engeletin dramatically suppressed the activation of microglia and apoptosis induced by SEV in the hippocampus of neonatal mice. Furthermore, the inhibition of PPAR-γ obviously reversed the abovementioned effects of engeletin in the hippocampus of newborn mice. In conclusion, this study verified that engeletin notably ameliorated SEV-induced cognitive deficiencies in neonatal mice at least partially by mediating the expression of PPAR-γ.

Prospective association of general anesthesia with risk of cognitive decline in a Chinese elderly community population

As life expectancy increases and the population grows, the number of surgeries performed each year is likely to continue to increase. We evaluated whether surgery with general anesthesia increases risk for cognitive impairment in a Chinese elderly community population. The current data was obtained from the China Longitudinal Aging Study (cohort 1) and Shanghai Brain Aging study (cohort 2). Cohort 1 included 1545 elderly people with normal cognitive function, who underwent a screening process that included physical examination, medical history, baseline and 1-year follow-up assessments of cognitive function by a face-to-face interview. Cohort 2 included an additional 194 elderly people with normal cognitive function, all of whom, unlike cohort 1, underwent T1-phase MR imaging scans. In cohort 1, 127 elderly people with normal cognitive function transformed into mild cognitive impairment, 27 into dementia, while 1391 still maintained normal cognitive function. By using Cox regression analysis, we found that surgery with general anesthesia was a risk factor for cognitive impairment (p = 0.013, HR = 1.506, 95% CI 1.091-2.078); In cohort 2, we found that elderly people with a history of surgery with general anesthesia had lower Montreal Cognitive Assessment (MoCA) scores and smaller right amygdala volume (p < 0.05). Through correlation analysis, we found that the volume of the right amygdala was significantly correlated (p = 0.003, r = 0.212) with MoCA. Then by using the linear regression analysis (mediation model), we found that surgery with general anesthesia directly affected the MoCA score by affecting the volume of the right amygdala (B = 1.315, p = 0.036 95% CI 0.088-2.542). We confirm surgery with general anesthesia as a risk factor for cognitive impairment, and its mechanism may be related to its effect on the volume of the right amygdala.

Role of resting-state functional MRI in detecting brain functional changes following radiotherapy for head and neck cancer: a systematic review and meta-analysis

PURPOSE

Increasing evidence implicates changes in brain function following radiotherapy for head and neck cancer as precursors for brain dysfunction. These changes may thus be used as biomarkers for early detection. This review aimed to determine the role of resting-state functional magnetic resonance imaging (rs-fMRI) in detecting brain functional changes.

METHODS

A systematic search was performed in the PubMed, Scopus, and Web of Science (WoS) databases in June 2022. Patients with head and neck cancer treated with radiotherapy and periodic rs-fMRI assessments were included. A meta-analysis was performed to determine the potential of rs-fMRI for detecting brain changes.

RESULTS

Ten studies with a total of 513 subjects (head and neck cancer patients, n = 437; healthy controls, n = 76) were included. A significance of rs-fMRI for detecting brain changes in the temporal and frontal lobes, cingulate cortex, and cuneus was demonstrated in most studies. These changes were reported to be associated with dose (6/10 studies) and latency (4/10 studies). A strong effect size (r = 0.71, p < 0.001) between rs-fMRI and brain changes was also reported, suggesting rs-fMRI's capability for monitoring brain alterations.

CONCLUSION

Resting-state functional MRI is a promising tool for detecting brain functional changes following head and neck radiotherapy. These changes are correlated with latency and prescription dose.

Emergence delirium and postoperative delirium associated with high plasma NfL and GFAP: an observational study

Background

Neuroinflammation and neuronal injury have been reported to be associated with the development of postoperative delirium in both preclinical and clinical settings. This study aimed to investigate the potential correlation between biomarkers of neurofilament light chain and glial fibrillary acidic protein and emergence and postoperative delirium in elderly patients undergoing surgery.

Methods

Patients who developed emergence delirium (n = 30) and postoperative delirium (n = 32), along with their matched controls, were enrolled after obtaining ethics approval and written informed consent. Delirium was assessed using the Confusion Assessment Method for the Intensive Care Unit or Confusion Assessment Method scale, and blood samples were collected before and after surgery for plasma neurofilament light chain and glial fibrillary acidic protein measurements using a single-molecule array.

Results

The study found that in patients with emergence delirium, the increase in plasma neurofilament light chain protein levels during surgery was significantly higher than in non-delirium patients (P = 0.002). Additionally, in patients with postoperative delirium, both the increase in plasma neurofilament light chain protein levels (P < 0.001) and the increase in plasma glial fibrillary acidic protein levels during surgery (P = 0.008) were significantly higher than in non-delirium patients. Multivariate logistic regression analysis showed that the increase in plasma neurofilament light chain protein was associated with emergence delirium (adjusted OR = 1.872, P = 0.005), and the increase in plasma glial fibrillary acidic protein was associated with postoperative delirium (adjusted OR = 1.419, P = 0.016). Moreover, the American Society of Anesthesiologists Physical Status Classification and surgical duration were also found to be associated with delirium in elderly patients.

Conclusion

Our findings suggest that emergence delirium is linked to elevated levels of neurofilament light chain, a biomarker of axonal injury, during surgery. Furthermore, in addition to axonal injury, postoperative delirium was also associated with an increase in glial fibrillary acidic protein, a marker of astrocyte activation.

Isoflurane Rapidly Modifies Synaptic and Cytoskeletal Phosphoproteomes of the Supraoptic Nucleus of the Hypothalamus and the Cortex

INTRODUCTION

Despite the widespread use of general anaesthetics, the mechanisms mediating their effects are still not understood. Although suppressed in most parts of the brain, neuronal activity, as measured by FOS activation, is increased in the hypothalamic supraoptic nucleus (SON) by numerous general anaesthetics, and evidence points to this brain region being involved in the induction of general anaesthesia (GA) and natural sleep. Posttranslational modifications of proteins, including changes in phosphorylation, enable fast modulation of protein function which could be underlying the rapid effects of GA. In order to identify potential phosphorylation events in the brain-mediating GA effects, we have explored the phosphoproteome responses in the rat SON and compared these to cingulate cortex (CC) which displays no FOS activation in response to general anaesthetics.

METHODS

Adult Sprague-Dawley rats were treated with isoflurane for 15 min. Proteins from the CC and SON were extracted and processed for nano-LC mass spectrometry (LC-MS/MS). Phosphoproteomic determinations were performed by LC-MS/MS.

RESULTS

We found many changes in the phosphoproteomes of both the CC and SON in response to 15 min of isoflurane exposure. Pathway analysis indicated that proteins undergoing phosphorylation adaptations are involved in cytoskeleton remodelling and synaptic signalling events. Importantly, changes in protein phosphorylation appeared to be brain region specific suggesting that differential phosphorylation adaptations might underlie the different neuronal activity responses to GA between the CC and SON.

CONCLUSION

In summary, these data suggest that rapid posttranslational modifications in proteins involved in cytoskeleton remodelling and synaptic signalling events might mediate the central mechanisms mediating GA.

Comparative effect of deliberate hypotensive anesthesia using nitroglycerine vs. phentolamine on event related potentials and cognitive functions in patients undergoing septoplasty: a randomized controlled trial

BACKGROUND

Postoperative cognitive dysfunction is a noteworthy complication of deliberate hypotensive anesthesia. The aim of this work was to compare the effect of deliberate hypotensive anesthesia using nitroglycerine versus phentolamine on event-related potentials and cognitive function in patients undergoing septoplasty surgery.

METHODS

This prospective randomized controlled trial was conducted on 80 patients indicated for septoplasty under general anesthesia; 40 patients received intra-operative Nitroglycerine and 40 patients received intra-operative Phentolamine. Cognitive assessment (using Paired Associate Learning test (PALT) and Benton Visual Retention test (BVRT)) and P300 recording were done for all included patients pre-operatively and one week postoperatively.

RESULTS

The scores of PALT and Benton BVRT significantly declined one week following surgery in both Nitroglycerine and Phentolamine groups. There was no statistically significant difference between Nitroglycerine and Phentolamine groups in the postoperative decline in either PALT or BVRT (P-value = 0.342, 0.662 respectively). The values of P300 latency showed a significant delay one week following surgery in both Nitroglycerine and Phentolamine groups (P-value ≤ 0.001, 0.001), but in Nitroglycerine group, the delay is significantly higher than in Phentolamine group (P-value = 0.003). The values of P300 amplitude significantly decreased one week following surgery in both Nitroglycerine and Phentolamine groups (P-value ≤ 0.001, 0.001), but there was no statistically significant difference between Nitroglycerine and Phentolamine groups (P-value = 0.099).

CONCLUSION

Phentolamine is preferred over nitroglycerin in deliberate hypotensive anesthesia because it has less harmful effect on cognitive function than nitroglycerin.

How Does Cross-Sectional Imaging Impact the Management of Patients With Single Ventricle After Bidirectional Cavopulmonary Connection?

BACKGROUND

There is currently no consensus regarding the use of surveillance cross-sectional imaging in pediatric patients after bidirectional cavopulmonary connection (BDCPC). We sought to determine how computed tomography with angiography (CTA) and cardiac magnetic resonance (CMR) imaging impacted the clinical management of pediatric patients after BDCPC.

METHODS

A single-center retrospective study including patients with single ventricle who had BDCPC between 2010 and 2019, and CTA/CMR studies obtained in these patients, at ≤5 years of age, and with Glenn physiology. Repeat studies on the same patient were included if the clinical situation had changed. The impact of CTA/CMR studies was categorized as major, minor, or none.

RESULTS

Twenty-four patients (63% male) and 30 imaging studies (22 CTAs) were included. 60% were obtained in patients with hypoplastic left heart syndrome (HLHS); most common indication was Follow-up after an intervention (23%). 6 CMRs were performed on stable HLHS patients as part of a research protocol, with no clinical concerns. The overall impact of CTA/CMR studies was major in 13 cases (43.3%). CTA/CMR studies performed ≥1 year of age (62.5% vs 21.4%, P = .02) and in non-HLHS patients (66.7% vs 27.8%, P = .035) were associated with major impact. Also, 2/6 Research studies were associated with a major impact.

CONCLUSIONS

CTA/CMR imaging in pediatric patients with SV after BDCPC was associated with significant clinical impact in over 40% of cases, with a higher impact if obtained in patients ≥1 year of age and in non-HLHS patients. We cannot disregard the possibility of CMR as a surveillance imaging modality in this population.

Current Drug Targets in Alzheimer's Associated Memory Impairment: A Comprehensive Review

Alzheimer's disease (AD) is the most prevalent form of dementia among geriatrics. It is a progressive, degenerative neurologic disorder that causes memory and cognition loss. The accumulation of amyloid fibrils and neurofibrillary tangles in the brain of AD patients is a distinguishing feature of the disease. Therefore, most of the current therapeutic goals are targeting inhibition of beta-amyloid synthesis and aggregation as well as tau phosphorylation and aggregation. There is also a loss of the cholinergic neurons in the basal forebrain, and first-generation therapeutic agents were primarily focused on compensating for this loss of neurons. However, cholinesterase inhibitors can only alleviate cognitive symptoms of AD and cannot reduce the progression of the disease. Understanding the molecular and cellular changes associated with AD pathology has advanced significantly in recent decades. The etiology of AD is complex, with a substantial portion of sporadic AD emerging from unknown reasons and a lesser proportion of early-onset familial AD (FAD) caused by a mutation in several genes, such as the amyloid precursor protein (APP), presenilin 1 (PS1), and presenilin 2 (PS2) genes. Hence, efforts are being made to discover novel strategies for these targets for AD therapy. A new generation of AChE and BChE inhibitors is currently being explored and evaluated in human clinical trials for AD symptomatic treatment. Other approaches for slowing the progression of AD include serotonergic modulation, H3 receptor antagonism, phosphodiesterase, COX-2, and MAO-B inhibition. The present review provides an insight into the possible therapeutic strategies and their molecular mechanisms, enlightening the perception of classical and future treatment approaches.

Repeated sevoflurane exposures inhibit neurogenesis by inducing the upregulation of glutamate transporter 1 in astrocytes

Sevoflurane is a widely used general anaesthetic in paediatric patients. Although repeated sevoflurane exposure is known to cause neurodevelopmental disorders in children, the mechanism of this neurotoxicity remains largely unknown. Herein, we investigated the role of glutamate transporter 1 (GLT1) in sevoflurane-induced decreased neurogenesis. Neonatal rat pups (postnatal Day 7, PN7) were exposed to 3% sevoflurane for 2 h for three consecutive days. Neuron loss and decreased neurogenesis have been observed in the neonatal rat brain, along with decreased number of astrocytes. Apoptotic astrocytes were observed after repeated sevoflurane exposure in vitro, resulting in decreased levels of brain-derived neurotrophic factor (BDNF). Calcium overload was observed in astrocytes after repeated sevoflurane exposure, in addition to upregulation of GLT1. Inhibition of GLT1 activity ameliorates repeated sevoflurane exposure-induced cognitive deficits in adult rats. Mechanically, the upregulation of GLT1 was caused by the activation of mRNA translation. RNA-sequencing analysis further confirmed that translation-related genes were activated by repeated sevoflurane exposure. These results indicate that cognitive deficits caused by repeated sevoflurane exposure during PN7-9 are triggered decreased neurogenesis. The proposed underlying mechanism involves upregulation of apoptosis in astrocytes induced by GLT1; therefore, we propose GLT1 as a potential pharmacological target for brain injury in paediatric practice.

Effect of combined use of cerebral oximetry and electroencephalogram monitoring on the incidence of perioperative neurocognitive disorders in adult cardiac and non-cardiac surgery: A systematic review of randomized and non-randomized trials

Background: There is insufficient evidence to recommend using either intraoperative cerebral oximetry or (processed) electroencephalogram (EEG) alone for preventing perioperative neurocognitive disorders (PNDs). Objective: To evaluate the effectiveness of combined use of cerebral oximetry and electroencephalogram-guided anesthesia on the incidence of PNDs in adult patients undergoing cardiac and non-cardiac interventions. Methods: A PICOS - based systematic review of English articles using Pubmed and Embase (from inception to August 2022) was performed. There were no exclusion criteria regarding the type of the study. Abstract proceedings and new study protocols or ongoing studies were not included. Review articles were analyzed in search of eligible references. All possible terms that were illustrative of PNDs were used. Results: Among the 63 full manuscripts that were analyzed in detail, 15 met the inclusion criteria. We found 2 retrospective, 8 prospective observational and 5 randomized controlled trials of which 1 did not evaluate the use of neuromonitoring in the randomization process. The definition and the methods used to diagnose PNDs were very heterogeneous. Only 8 studies used an algorithm to avoid/treat cerebral oxygen desaturation and/or to treat EEG abnormalities. Overall, there was a tendency towards less PNDs in studies where such an algorithm was used. Conclusions: Our results suggest that integrating information obtained from cerebral oximetry and an EEG monitor may reduce the incidence of PNDs whenever an adapted algorithm is used to improve brain function.

Mild acute stress prevents the memory impairment induced by long-term isoflurane anesthesia

Objectives

Long-term isoflurane anesthesia exposure could result in postoperative cognitive dysfunction (POCD). Preoperative stress is also reported to be a risk factor of POCD. However, it is unknown whether acute stress could impair memory after long-term isoflurane anesthesia.

Methods

In this study, we categorized the mice with acute stress into mild (30 min restraint stress), moderate (60 min restraint stress), and severe (120 min restraint stress) stress groups and then we used Open-Field Test (OFT) to detect whether different scales of acute restraint stress successfully induced acute stress in mice. The memory performance of mice was measured using contextual and cued memory test, and the brain-derived neurotrophic factor protein levels of hippocampus was detected by Western blot.

Results

We verified that mild stress has pro-cognitive effect, but severe stress has amnestic effect. Moreover, we found that mild and moderate other than severe acute stress could partially attenuate the memory impairment induced by long-term isoflurane anesthesia.

Conclusion

Mild and moderate acute stress could partially attenuate the memory impairment induced by long-term isoflurane anesthesia.

Enhanced hippocampal neurogenesis mediated by PGC-1α-activated OXPHOS after neonatal low-dose Propofol exposure

Background

Developing brain is highly plastic and can be easily affected. Growing pediatric usage of anesthetics during painless procedures has raised concerns about the effect of low-dose anesthetics on neurodevelopment. It is urgent to ascertain the neuronal effect of low-dose Propofol, a widely used anesthetic in pediatrics, on developing brains.

Methods

The behavioral tests after neonatal exposure to low-dose/high-dose Propofol in mice were conducted to clarify the cognitive effect. The nascent cells undergoing proliferation and differentiation stage in the hippocampus and cultured neural stem cells (NSCs) were further identified. In addition, single-nuclei RNA sequencing (snRNA-seq), NSCs bulk RNA-seq, and metabolism trials were performed for pathway investigation. Furthermore, small interfering RNA and stereotactic adenovirus injection were, respectively, used in NSCs and hippocampal to confirm the underlying mechanism.

Results

Behavioral tests in mice showed enhanced spatial cognitive ability after being exposed to low-dose Propofol. Activated neurogenesis was observed both in hippocampal and cultured NSCs. Moreover, transcriptome analysis of snRNA-seq, bulk RNA-seq, and metabolism trials revealed a significantly enhanced oxidative phosphorylation (OXPHOS) level in NSCs. Furthermore, PGC-1α, a master regulator in mitochondria metabolism, was found upregulated after Propofol exposure both in vivo and in vitro. Importantly, downregulation of PGC-1α remarkably prevented the effects of low-dose Propofol in activating OXPHOS and neurogenesis.

Conclusions

Taken together, this study demonstrates a novel alteration of mitochondrial function in hippocampal neurogenesis after low-dose Propofol exposure, suggesting the safety, even potentially beneficial effect, of low-dose Propofol in pediatric use.

Potential Markers of Neurocognitive Disorders After Cardiac Surgery: A Bibliometric and Visual Analysis

Background

Identifying useful markers is essential for diagnosis and prevention of perioperative neurocognitive disorders (PNDs). Here, we attempt to understand the research basis and status, potential hotspots and trends of predictive markers associated with PNDs after cardiac surgery via bibliometric analysis.

Methods

A total of 4,609 original research articles and reviews that cited 290 articles between 2001 and 2021 were obtained from the Web of Science Core Collection (WoSCC) as the data source. We used the software CiteSpace to generate and analyze visual networks of bibliographic information, including published years and journals, collaborating institutions, co-cited references, and co-occurring keywords.

Results

The number of annual and cumulative publications from 2001 to 2021 has been increasing on the whole. The Harvard Medical School was a very prolific and important institution in this field. The journal of Ann Thorac Surg (IF 4.33) had the most publications, while New Engl J Med was the most cited journal. Neuron-specific enolase (NSE), S100b and kynurenic acid (KYNA) were frequently discussed as possible markers of PNDs in many references. Cardiopulmonary bypass (CPB) was a keyword with high frequency (430) and sigma (6.26), and inflammation was the most recent burst keyword.

Conclusion

Potential markers of PNDs has received growing attention across various disciplines for many years. The research basis mainly focuses on three classic biomarkers of S100b, NSE, and KYNA. The most active frontiers are the inflammation-related biomarkers (e.g., inflammatory cells, cytokines, or mediators) and surgery-related monitoring parameters (e.g., perfusion, oxygen saturation, and the depth of anesthesia).

Remimazolam induced cognitive dysfunction in mice via glutamate excitotoxicity

Objective

Several lines of evidence demonstrated the role of anesthetic drugs in cognitive functions. Some anesthetic agents have been confirmed to be associated with long-term spatial memory and learning in aged animal models.

Methods

C57BL/6 mice were divided into four different groups based on different concentrations of remimazolam treatments. Behavioral phenotype was observed by open field, rota rod, Morris water maze, and elevated plus maze test. Western blot was performed to see the expression pattern of different proteins. Confocal microscopy images were taken for neuronal and glial cells to see the effect of remimazolam on CNS cells.

Results

We showed that remimazolam, a new anesthetic drug, impaired cognitive behavior. Repetitive doses of remimazolam have been found to induce neuronal loss with a significant change in morphology. Here, we showed that a higher concentration of remimazolam had a significant effect on CNS cell activation. We showed that remimazolam caused memory dysfunction by inducing neuronal apoptosis via glutamate excitotoxicity. It also exhibited amyloid β plaque in the brain via abnormal phosphorylation of tau protein. Remimazolam-mediated regulation of glial cells in mouse cortex was observed and robust activation of astrocytes and microglial cells was found. Finally, we assessed the behavioral phenotype of mice and found that treatment with remimazolam induced significant behavioral changes and memory dysfunction.

Conclusions

This study provides insight into the mechanism of anesthetic drug-induced memory deficits and may help improve the therapeutic effects of anesthesia agents in clinical applications.

Effect of electroacupuncture on discomfort during gastroscopy: a study protocol for a randomized controlled trial

Background

Gastroscopy procedures are frequently performed under general sedation to minimize discomfort. Patients who refuse a sedative injection may experience more discomfort and adverse reactions such as pain and nausea. These instances reduce patient compliance and willingness to participate in future procedures. Acupuncture has been shown to have an anti-nausea and analgesic effect; however, there is limited data available that demonstrates the efficacy of acupuncture when applied before gastroscopy.

Methods

A total of 60 participants will be randomly assigned to the electroacupuncture (EA) group and the sham electroacupuncture (SEA) group at a ratio of 1:1. Acupuncture treatment will be performed before gastroscopy for a duration of 30 min. All patients will complete detailed questionnaires at 30 min and 7 days post-procedure to record the severity of their symptoms. The primary outcome will be the average of 4 standard visual analogue scale (VAS) scores in the categories of nausea, vomiting, throat discomfort, and agitation as reported by the patient. The secondary outcomes will be patient’s anxiety level as recorded by the 6-item short form of the State-Trait Anxiety Inventory (STAI-S6) and Amsterdam Pre-Operative Anxiety and Information Scale (APAIS), preference in a future endoscopy, pulse oxygen saturation (SpO2), heart rate (HR), and blood pressure (BP). Anxiety scales will be assessed before and after acupuncture; others will be completed at 30 min and 7 days post-procedure. The duration of the gastroscopy and the number of biopsies will be recorded after operation.

Discussion

This randomized controlled trial will explore the feasibility of the further clinical application of electroacupuncture for the improvement of patient discomfort during gastroscopy without systemic sedation.

Trial registration

ChiCTR2000040726. This trial has been approved by the Ethics Committee of Shanghai Municipal Hospital of Traditional Chinese Medicine (2020SHL-KY-11). Registration date 12 August 2020.

Assessments of prolonged effects of desflurane and sevoflurane on motor learning deficits in aged AppNL-G-F/NL-G-F mice

As the proportion of elderly in society increases, so do the number of older patients undergoing surgical procedures. This is concerning as exposure to anesthesia has been identified as a risk factor for Alzheimer's disease (AD). However, the causal relationship between clinical AD development and anesthesia remains conjectural. Preclinical studies have demonstrated that anesthesia, such as halothane, isoflurane, and sevoflurane, induces AD-like pathophysiological changes and cognitive impairments in transgenic mouse models of AD. Desflurane does not have these effects and is expected to have more potential for use in elderly patients, yet little is known about its effects, especially on non-cognitive functions, such as motor and emotional functions. Thus, we examined the postanesthetic effects of desflurane and sevoflurane on motor and emotional function in aged App^{NL-G-F/NL-G-F} (App-KI) mice. This is a recently developed transgenic mouse model of AD exhibiting amyloid β peptide (Aβ) amyloidosis and a neuroinflammatory response in an age-dependent manner without non-physiological amyloid precursor protein (APP) overexpression. Mice were subjected to a short behavioral test battery consisting of an elevated plus maze, a balance beam test, and a tail suspension test seven days after exposure to 8.0% desflurane for 6 h or 2.8% sevoflurane for 2 h. App-KI mice showed significant increments in the percentage of entry and time spent in open arms in the elevated plus maze, increments in the number of slips and latency to traverse for the balance beam test, increments in the limb clasping score, increments in immobile duration, and decrements in latency to first immobile episode for the tail suspension test compared to age-matched wild type (WT) controls. Desflurane- and sevoflurane-exposed App-KI mice showed a delayed decrement in the number of slips for each trial in the balance beam test, while air-treated App-KI mice rapidly improved their performance, and increased their clasping behavior in the tail suspension test. Furthermore, App-KI inhibited the change in membrane GluA3 following exposure to anesthetics in the cerebellum. These results suggest high validity of App-KI mice as an animal model of AD.

Prospective Rates, Longitudinal Associations, and Factors Associated With Comorbid Insomnia Symptoms and Perceived Cognitive Impairment

Background

Insomnia and cognitive impairment are both common conditions experienced by people diagnosed with cancer. Individually, these conditions have negative impacts on functioning, but the combined burden has yet to be evaluated. The purpose of this research was to estimate rates of comorbid insomnia and perceived cognitive impairments, examine the longitudinal associations between these two conditions, and identify demographic and clinical factors associated with reporting both insomnia and perceived cognitive impairment.

Methods

In this secondary analysis, a heterogeneous sample of 962 patients completed the Insomnia Severity Index (ISI) and the Cognitive Failures Questionnaire (CFQ) at the time of their cancer surgery (baseline; T1) and then again at 2 (T2), 6 (T3), 10 (T4), 14 (T5), and 18 (T6) months. Correlations and partial correlations, controlling for age and education level, were computed at each time point to assess the relationship between ISI and CFQ scores. Cross-lagged correlations assessed associations between ISI and CFQ scores over time. Proportions of patients with comorbid insomnia and cognitive impairments were calculated and logistic regressions investigated changes over time in these proportions. ANOVAs, logistic regressions, ordinal regressions, and multinomial regressions were used to identify risk factors of having comorbid insomnia and cognitive difficulties.

Results

Significant and bidirectional correlations between ISI and CFQ scores were observed at each time point and over time. The proportion of patients having both clinical levels of insomnia and perceived cognitive difficulties ranged from 18.73 to 25.84% across time points and this proportion was significantly greater at T1 and T2 than T4, T5, and T6. Participants who reported comorbid insomnia and cognitive impairment were more likely to be younger, female, not currently working, currently receiving chemotherapy, with clinical levels depression and anxiety, and using antidepressants or anxiolytics.

Conclusion

Comorbid insomnia and perceived cognitive impairment affects around one in five patients and is more frequent at the beginning of the cancer care trajectory. The relationship between insomnia and cognitive impairment appears to be bidirectional. Insomnia may represent an important patient level vulnerability that when identified and treated can improve perception of cognitive function.

Effect of Thiopental on Ischemic Stroke in Rat Brain in Spontaneously Hypertensive Rats

Motivation and Problem Statement. Thiopental is an anesthetic drug related to the condition of controlling the area of neurological contexts. This study is related to the analysis of effectiveness for the condition of thiopental application on spontaneously hypertensive rats. Methodology. We have evaluated the thiopental induction as the anesthetic agent. The hypertensive rats were selected to administer thiopental in the form of anesthesia. The selection and application of hypertensive strokes are related to the derivation of an inducible model to assess the efficacy for analyzing the ischemic stroke parameters which relate to the human body. We used middle cerebral artery occlusion (MCAO) models related to spontaneous hypertension with the area of examining the complications in ischemic stroke. Results and Conclusion. The study focused on the experimental analysis based on the selection of spontaneously hypertensive rats associated with the incidence of ischemic stroke. Application of thiopental has reported the weak functionality and mechanism on the relaxation of neuronal activity in the case of rat brain. The considered population of the spontaneously hypertensive rats is evaluated based on the condition of effectiveness as well as the duration of the medication effects within the rat brain. Involvement of thiopental in the case of ischemic stroke has provided the area of risk development for high rate of death incidences after occurrence of acute ischemic stroke. A complication in the area of defining neuroprotective actions provides difficulty in drawing an appropriate conclusion of the study.

Safety and Efficacy of Ketamine-Fentanyl-Dexmedetomidine-Induced Anesthesia and Analgesia in Neonatal and Aged Rats

The efficiency of many anesthetic regimens is controversial, with side effects especially in the vulnerable children and old population. The study aimed to evaluate the safety and efficacy of low-dose combination of ketamine, fentanyl, and dexmedetomidine (KFD) for anesthesia and analgesia in the neonatal and elderly rats. KFD rapidly induced anesthesia and analgesia in either postnatal days 6 (P6) or 13 months (13M) old rats. Meanwhile, KFD administration had no adverse effects on the cardiovascular and respiratory systems. Compared with control group, there were no distinct morphologic changes in kidney, liver, and brain in KFD group. Moreover, administration of KFD had no influence on hepatic and renal function in rats of both ages. Furthermore, there was no obvious difference in cognitive function between control and KFD groups. These results indicated that the administration of KFD combination offered safe and efficient anesthesia. Collectively, our results suggest the potential implication of the KFD combination in anesthesia management.

A survey of current practices, attitudes and demands of anaesthesiologists regarding the depth of anaesthesia monitoring in China

Background

In this study, we aimed to analyse survey data to explore two different hypotheses; and for this purpose, we distributed an online survey to Chinese anaesthesiologists. The hypothetical questions in this survey include: (1) Chinese anaesthesiologists mainly use the depth of anaesthesia (DoA) monitors to prevent intraoperative awareness and (2) the accuracy of these monitors is the most crucial performance factor during the clinical daily practice of Chinese anaesthesiologists.

Methods

We collected and statistically analysed the response of a total of 12,750 anesthesiologists who were invited to participate in an anonymous online survey. The Chinese Society of Anaesthesiologists (CSA) trial group provided the email address of each anaesthesiologist, and the selection of respondents was random from the computerized system.

Results

The overall response rate was 32.0% (4037 respondents). Only 9.1% (95% confidence interval, 8.2-10.0%) of the respondents routinely used DoA monitors. Academic respondents (91.5, 90.3-92.7%) most frequently used DoA monitoring to prevent awareness, whereas nonacademic respondents (88.8, 87.4-90.2%) most frequently used DoA monitoring to guide the delivery of anaesthetic agents. In total, the number of respondents who did not use a DoA monitor and whose patients experienced awareness (61.7, 57.8-65.6%) was significantly greater than those who used one or several DoA monitors (51.5, 49.8-53.2%). Overall, the crucial performance factor during DoA monitoring was considered by 61.9% (60.4-63.4%) of the respondents to be accuracy. However, most respondents (95.7, 95.1-96.3%) demanded improvements in the accuracy of the monitors for DoA monitoring. In addition, broad application in patients of all ages (86.3, 85.2-87.4%), analgesia monitoring (80.4, 79.2-81.6%), and all types of anaesthetic agents (75.6, 74.3-76.9%) was reported. In total, 65.0% (63.6-66.5%) of the respondents believed that DoA monitors should be combined with EEG and vital sign monitoring, and 53.7% (52.1-55.2%) believed that advanced DoA monitors should include artificial intelligence.

Conclusions

Academic anaesthesiologists primarily use DoA monitoring to prevent awareness, whereas nonacademic anaesthesiologists use DoA monitoring to guide the delivery of anaesthetics. Anaesthesiologists demand high-accuracy DoA monitors incorporating EEG signals, multiple vital signs, and antinociceptive indicators. DoA monitors with artificial intelligence may represent a new direction for future research on DoA monitoring.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12871-021-01510-7.

Anesthesia can alter the levels of corticosterone and the phosphorylation of signaling molecules

Objective

Neuroscience research using laboratory animals has increased over the years for a number of reasons. Some of these studies require the use of anesthetics for surgical procedures. However, the use of anesthetics promotes several physiological changes that may interfere with experimental results. Although the anesthetics and methods of delivery used to vary, one of the most common is ketamine associated with another compound such as xylazine. We aimed to evaluate the effect of ketamine and xylazine (KX) on corticosterone levels and on the degree of phosphorylation of p44/42 (ERK1/2), Src kinases and calcium/calmodulin-dependent kinase II (CAMKII). We also compared the effects of KX on sleep deprivation, which is known to affect the hormonal profile including corticosterone.

Results

We found that the use of KX can increase corticosterone levels and alter the degree of phosphorylation of signaling proteins.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13104-021-05763-w.

Repeated neonatal sevoflurane induced neurocognitive impairment through NF-κB-mediated pyroptosis

Background

Exposure to general anesthesia (GA) during the postnatal period is associated with neuroinflammation and long-term neurocognitive impairment in preclinical and clinical settings. Pyroptosis is a novel type of programmed cell death that, along with inflammation, has been found to play an important role in the mechanism of diverse neurological diseases. However, its roles in GA-induced neuroinflammation and neurocognitive impairment in the developing brain have not been investigated.

Methods

Rats at postnatal day 6 or primary hippocampal neurons at 9 days in vitro received 3% sevoflurane for 2 h daily for three consecutive days. A pharmacological inhibitor of nuclear factor (NF)-κB (BAY 11-7082) was administered to suppress NF-κB activation. Histological and biochemical analyses were performed to assess the pyroptosis as well as neuronal and synaptic damage both in vivo and in vitro. In addition, behavioral tests were performed to evaluate neurocognitive ability in rats.

Results

Repeated sevoflurane exposure activated NF-κB-mediated pyroptosis and neuroinflammation in the hippocampus in developing rats, damaged the neuronal morphology and synaptic integrity, and induced neurocognitive impairment in rats. BAY 11-7082 treatment suppressed the activation of pyroptosis, attenuated the neuronal and synaptic damage, and ameliorated the neurocognitive impairment induced by repeated sevoflurane administration to developing rats.

Conclusions

Repeated sevoflurane GA may induce neuroinflammation and neurocognitive impairment in developing rats via the activation of NF-κB-mediated pyroptosis. Our findings characterize a novel role of pyroptosis as a potential therapeutic target in neuroinflammation after repeated neonatal GA.

TRPV1 Antagonist Prevents Neonatal Sevoflurane-Induced Synaptic Abnormality and Cognitive Impairment in Mice Through Regulating the Src/Cofilin Signaling Pathway

Long-term neurodevelopmental disorders following neonatal anesthesia have been reported both in young animals and in children. The activation of transient receptor potential vanilloid 1 (TRPV1) channels in hippocampus adversely affects neurodevelopment. The current study explored the underlying mechanism of TRPV1 channels on long-lasting cognitive dysfunction induced by anesthetic exposure to the developing brain. we demonstrated that TRPV1 expression was increased after sevoflurane exposure both in vitro and in vivo. Sevoflurane exposure to hippocampal neurons decreased the synaptic density and the surface GluA1 expression, as well as increased co-localization of internalized AMPAR in early and recycling endosomes. Sevoflurane exposure to newborn mice impaired learning and memory in adulthood, and reduced AMPAR subunit GluA1, 2 and 3 expressions in the crude synaptosomal fractions from mouse hippocampus. The inhibition of TRPV1 reversed the phenotypic changes induced by sevoflurane. Moreover, sevoflurane exposure increased Src phosphorylation at tyrosine 416 site thereby reducing cofilin phosphorylation. TRPV1 blockade reversed these suppressive effects of sevoflurane. Our data suggested that TRPV1 antagonist may protect against synaptic damage and cognitive dysfunction induced by sevoflurane exposure during the brain developing stage.

Effect of Xenon Treatment on Gene Expression in Brain Tissue after Traumatic Brain Injury in Rats

The overactivation of inflammatory pathways and/or a deficiency of neuroplasticity may result in the delayed recovery of neural function in traumatic brain injury (TBI). A promising approach to protecting the brain tissue in TBI is xenon (Xe) treatment. However, xenon's mechanisms of action remain poorly clarified. In this study, the early-onset expression of 91 target genes was investigated in the damaged and in the contralateral brain areas (sensorimotor cortex region) 6 and 24 h after injury in a TBI rat model. The expression of genes involved in inflammation, oxidation, antioxidation, neurogenesis and neuroplasticity, apoptosis, DNA repair, autophagy, and mitophagy was assessed. The animals inhaled a gas mixture containing xenon and oxygen (ϕXe = 70%; ϕO₂ 25-30% 60 min) 15-30 min after TBI. The data showed that, in the contralateral area, xenon treatment induced the expression of stress genes (Irf1, Hmox1, S100A8, and S100A9). In the damaged area, a trend towards lower expression of the inflammatory gene Irf1 was observed. Thus, our results suggest that xenon exerts a mild stressor effect in healthy brain tissue and has a tendency to decrease the inflammation following damage, which might contribute to reducing the damage and activating the early compensatory processes in the brain post-TBI.

Hepatic Encephalopathy: From Metabolic to Neurodegenerative

Hepatic encephalopathy (HE) is a neuropsychiatric syndrome of both acute and chronic liver disease. As a metabolic disorder, HE is considered to be reversible and therefore is expected to resolve following the replacement of the diseased liver with a healthy liver. However, persisting neurological complications are observed in up to 47% of transplanted patients. Several retrospective studies have shown that patients with a history of HE, particularly overt-HE, had persistent neurological complications even after liver transplantation (LT). These enduring neurological conditions significantly affect patient's quality of life and continue to add to the economic burden of chronic liver disease on health care systems. This review discusses the journey of the brain through the progression of liver disease, entering the invasive surgical procedure of LT and the conditions associated with the post-transplant period. In particular, it will discuss the vulnerability of the HE brain to peri-operative factors and post-LT conditions which may explain non-resolved neurological impairment following LT. In addition, the review will provide evidence; (i) supporting overt-HE impacts on neurological complications post-LT; (ii) that overt-HE leads to permanent neuronal injury and (iii) the pathophysiological role of ammonia toxicity on astrocyte and neuronal injury/damage. Together, these findings will provide new insights on the underlying mechanisms leading to neurological complications post-LT.

Visual Evoked Potentials in Operated Primary Congenital Glaucoma: A Cross-Sectional Comparative Study

Background

To evaluate the VEP parameters in operated controlled primary congenital glaucoma (PCG) eyes and compare them to normal age similar children eyes.

Methods

A cross-sectional comparative study conducted on 34 (19 right) eyes of 26 (19 males) children operated for PCG and 30 (17 right) eyes of 22 (12 males) age similar control children in a university-based practice. All study participants were subjected to a standard protocol of examination and electrophysiological testing (single flash VEP response, light adapted, pupils not dilated), reporting on the P2 implicit time, N1-P1 and N2-P2 (amplitude).

Results

The mean±SD of the age of the study children and controls was 43.22±33.2 and 55.68±35.2 months respectively (p=0.217). The mean±SD IOP and cup/disc ratio of the study children were 18.4±5.2 and 5.2±3.3mmHg and 0.7±0.2 and 0.3±0.3 at presentation and at testing, respectively. The VEP testing was conducted after 21.5±21.3 months of surgery for PCG. There was no statistically significant differences in P2, N1-P1 and N2-P2 between patients and controls (p=0.941, 0.916,0.945, respectively). There was no statistically significant correlation between most of the clinical characteristics of the study eyes and any of the studied VEP parameters.

Conclusion

Operated controlled PCG eyes have VEP parameters that match their normal fellow children.

Dendritic spine remodeling and plasticity under general anesthesia

Ever since its first use in surgery, general anesthesia has been regarded as a medical miracle enabling countless life-saving diagnostic and therapeutic interventions without pain sensation and traumatic memories. Despite several decades of research, there is a lack of understanding of how general anesthetics induce a reversible coma-like state. Emerging evidence suggests that even brief exposure to general anesthesia may have a lasting impact on mature and especially developing brains. Commonly used anesthetics have been shown to destabilize dendritic spines and induce an enhanced plasticity state, with effects on cognition, motor functions, mood, and social behavior. Herein, we review the effects of the most widely used general anesthetics on dendritic spine dynamics and discuss functional and molecular correlates with action mechanisms. We consider the impact of neurodevelopment, anatomical location of neurons, and their neurochemical profile on neuroplasticity induction, and review the putative signaling pathways. It emerges that in addition to possible adverse effects, the stimulation of synaptic remodeling with the formation of new connections by general anesthetics may present tremendous opportunities for translational research and neurorehabilitation.

Ferroptosis contributes to isoflurane-induced neurotoxicity and learning and memory impairment

Ferroptosis is a novel type of programmed cell death, which is different from apoptosis and autophagic cell death. Recently, ferroptosis has been indicated to contribute to the in vitro neurotoxicity induced by isoflurane, which is one of the most common anesthetics in clinic. However, the in vivo position of ferroptosis in isoflurane-induced neurotoxicity as well as learning and memory impairment remains unclear. In this study, we mainly explored the relationship between ferroptosis and isoflurane-induced learning and memory, as well as the therapeutic methods in mouse model. Our results indicated that isoflurane induced the ferroptosis in a dose-dependent and time-dependent manner in hippocampus, the organ related with learning and memory ability. In addition, the activity of cytochrome c oxidase/Complex IV in mitochondrial electron transport chain (ETC) was increased by isoflurane, which might further contributed to cysteine deprivation-induced ferroptosis caused by isoflurane exposure. More importantly, isoflurane-induced ferroptosis could be rescued by both ferroptosis inhibitor (ferrostatin-1) and mitochondria activator (dimethyl fumarate), which also showed effective therapeutic action against isoflurane-induced learning and memory impairment. Taken together, our data indicate the close association among ferroptosis, mitochondria and isoflurane, and provide a novel insight into the therapy mode against isoflurane-induced learning and memory impairment.

Heart rate variability-derived features based on deep neural network for distinguishing different anaesthesia states

Background

Estimating the depth of anaesthesia (DoA) is critical in modern anaesthetic practice. Multiple DoA monitors based on electroencephalograms (EEGs) have been widely used for DoA monitoring; however, these monitors may be inaccurate under certain conditions. In this work, we hypothesize that heart rate variability (HRV)-derived features based on a deep neural network can distinguish different anaesthesia states, providing a secondary tool for DoA assessment.

Methods

A novel method of distinguishing different anaesthesia states was developed based on four HRV-derived features in the time and frequency domain combined with a deep neural network. Four features were extracted from an electrocardiogram, including the HRV high-frequency power, low-frequency power, high-to-low-frequency power ratio, and sample entropy. Next, these features were used as inputs for the deep neural network, which utilized the expert assessment of consciousness level as the reference output. Finally, the deep neural network was compared with the logistic regression, support vector machine, and decision tree models. The datasets of 23 anaesthesia patients were used to assess the proposed method.

Results

The accuracies of the four models, in distinguishing the anaesthesia states, were 86.2% (logistic regression), 87.5% (support vector machine), 87.2% (decision tree), and 90.1% (deep neural network). The accuracy of deep neural network was higher than those of the logistic regression (p < 0.05), support vector machine (p < 0.05), and decision tree (p < 0.05) approaches. Our method outperformed the logistic regression, support vector machine, and decision tree methods.

Conclusions

The incorporation of four HRV-derived features in the time and frequency domain and a deep neural network could accurately distinguish between different anaesthesia states; however, this study is a pilot feasibility study. The proposed method—with other evaluation methods, such as EEG—is expected to assist anaesthesiologists in the accurate evaluation of the DoA.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12871-021-01285-x.

Visual, Verbal and Everyday Memory 2 Years After Bariatric Surgery: Poorer Memory Performance at 1-Year Follow-Up

Severe obesity has been associated with reduced performance on tests of verbal memory in bariatric surgery candidates. There is also some evidence that bariatric surgery leads to improved verbal memory, yet these findings need further elucidation. Little is known regarding postoperative memory changes in the visual domain and how patients subjectively experience their everyday memory after surgery. The aim of the current study was to repeat and extend prior findings on postoperative memory by investigating visual, verbal, and self-reported everyday memory following surgery, and to examine whether weight loss and somatic comorbidity predict memory performance. The study was a prospective, observational study in which participants (n = 48) underwent cognitive testing at baseline, 1 and 2 years after bariatric surgery. Repeated measures analyses of variance revealed significantly poorer visual and verbal memory performance at the 1-year follow-up, with performance subsequently returning to baseline levels after 2 years. Verbal learning and self-reported everyday memory did not show significant postoperative changes. Memory performance at 1 year was not significantly predicted by weight loss, changes in C-reactive protein levels or postoperative somatic comorbidity (Type 2 diabetes, sleep apnea, and hypertension). The study demonstrated poorer visual and verbal memory performance at 1-year follow-up that returned to baseline levels after 2 years. These findings are in contrast to most previous studies and require further replication, however, the results indicate that postoperative memory improvements following bariatric surgery are not universal. Findings suggest that treatment providers should also be aware of patients potentially having poorer memory at 1 year following surgery.

Prenatal sevoflurane exposure: Effects of iron metabolic dysfunction on offspring cognition and potential mechanism

For decades, the neurotoxicity caused by anesthetics in mammalian brain development has gained increasing attention. Exposure to anesthetics leads to neurotoxicity and apoptosis of nerve cells, which in turn induces cognitive dysfunction. Although most of the data came from animal studies, general anesthetics have been shown to have adverse effects on cognitive function in infants and young children in recent years. This concern has led to a number of retrospective studies that observed an association between general anesthesia in pregnant women and neurobehavioral problems in fetuses or offspring. Every year, many pregnant women undergo non-obstetric anesthesia due to various reasons such as traffic accidents, fetal interventions, acute appendicitis, symptomatic cholelithiasis, and trauma. A matter of concern for these pregnant women is whether anesthesia has a detrimental effect on fetal brain development in the womb and whether the fetus has cognitive impairment after birth. In humans, the association of anesthetic exposure in infants with the long-term impairment of neurologic functions has been reported in several retrospective clinical studies. Recently, we have found that sevoflurane anesthesia during pregnancy in mice-induced cognitive impairment in the offspring by causing iron deficiency and inhibiting myelinogenesis. Sevoflurane is a commonly used general anesthetic in the hospitals, which can induce neurotoxicity and cause cognitive impairment in fetuses, infants, children, and adults. However, the exact mechanism of sevoflurane-induced damage to the central nervous system (CNS) is not fully understood. Based on our recent results, this paper reviewed the effects of sevoflurane on cognitive impairment and pathological changes such as neurogenesis, neuronal apoptosis, and iron metabolism dysfunction in the offspring.

Efficacy of an Oxycodone-Propofol Combination versus a Fentanyl-Propofol Combination in Conscious Sedation during Therapeutic Endoscopic Retrograde Cholangiopancreatography in Elderly Patients

BACKGROUND

With a rapidly aging population, the need for endoscopic retrograde cholangiopancreatography (ERCP) is increasing. The commonly used sedation anesthesia in ERCP is a combination of propofol and fentanyl, even though fentanyl may cause some adverse reactions such as respiratory depression.

OBJECTIVES

This study aimed to evaluate the efficacy of oxycodone combined with propofol versus fentanyl combined with propofol for sedation anesthesia during ERCP.

METHODS

A total of 193 patients aged from 65 to 80 years undergoing ERCP were enrolled and randomized into two groups: an "oxycodone combined with propofol" group (group OP, n = 97) and a "fentanyl combined with propofol" group (group FP, n = 96). The rate of perioperative adverse events as well as the recovery time, patients' satisfaction, and endoscopists' satisfaction were noted.

RESULTS

There was no difference in the frequency of hypotension or bradycardia between the two groups, but there were more episodes of desaturation (SpO2 <90% for >10 s in 8.3%), postoperative nausea (7.3%), and vomiting (5.2%) in group FP than in group OP. Patients' satisfaction in group FP was lower than that in group OP. The recovery time was longer in group FP than in group OP.

CONCLUSIONS

Oxycodone combined with propofol was effective in ERCP, with a low incidence of perioperative adverse events.

Caffeine reverses the unconsciousness produced by light anesthesia in the continued presence of isoflurane in rats

Currently no drugs are employed clinically to reverse the unconsciousness induced by general anesthetics. Our previous studies showed that caffeine, when given near the end of an anesthesia session, accelerated emergence from isoflurane anesthesia, likely caused by caffeine’s ability to elevate intracellular cAMP levels and to block adenosine receptors. These earlier studies showed that caffeine did not rouse either rats or humans from deep anesthesia (≥ 1 minimum alveolar concentration, MAC). In this current crossover study, we examined whether caffeine reversed the unconsciousness produced by light anesthesia (< 1 MAC) in the continued presence of isoflurane. The primary endpoint of this study was to measure isoflurane levels at the time of recovery of righting reflex, which was a proxy for consciousness. Rats were deeply anesthetized with 2% isoflurane (~1.5 MAC) for 20 minutes. Subsequently, isoflurane was reduced to 1.2% for 10 minutes, then by 0.2% every 10 min; animals were monitored until the recovery of righting reflex occurred, in the continued presence of isoflurane. Respiration rate, heart rate and electroencephalogram (EEG) were monitored. Our results show that caffeine-treated rats recovered their righting reflex at a significantly higher inspired isoflurane concentration, corresponding to light anesthesia, than the same rats treated with saline (control). Respiration rate and heart rate increased initially after caffeine injection but were then unchanged for the rest of the anesthesia session. Deep anesthesia is correlated with burst suppression in EEG recordings. Our data showed that caffeine transiently reduced the burst suppression time produced by deep anesthesia, suggesting that caffeine altered neuronal circuit function but not to a point where it caused arousal. In contrast, under light anesthesia, caffeine shifted the EEG power to high frequency beta and gamma bands. These data suggest that caffeine may represent a clinically viable drug to reverse the unconsciousness produced by light anesthesia.

Surveillance imaging in pediatric ependymoma

BACKGROUND

Management of pediatric patients with ependymoma includes posttreatment surveillance imaging to identify asymptomatic recurrences. However, it is unclear whether early detection translates into improved survival. The objective was to determine whether detection of ependymoma relapses on surveillance imaging translates into a survival benefit.

PROCEDURE

Patients with ependymoma aged <21 years at diagnosis treated in the Nemours' Children's Health System between January 2003 and October 2016 underwent chart review. Relapsed patients' charts were assessed for details of initial therapy, surveillance imaging regimen, details of relapse including detection and therapy, and outcome. Median follow up of the entire cohort was 6.5 years from diagnosis and 3.5 years from relapse.

RESULTS

Ninety of 198 (45%) patients experienced relapse with 61 (68%) detected by surveillance imaging and 29 (32%) detected based on symptoms. Five-year OS in the surveillance group was 67% (confidence interval [CI] 55-82%, SE 0.1) versus 51% (CI 35-73%, SE 0.19) in the symptoms group (P = .073). From relapse, the 3-year OS in the surveillance group was 62% (CI 50-78%, SE 0.11) versus 55% (CI 39-76%, SE 0.17) in the symptoms group (P = .063) and the 3-year SPFS was 45% (CI 33-61%, SE 0.16) in the surveillance group versus 32% (CI 19-55%, SE 0.27) in the symptoms group (P = .028).

CONCLUSION

Surveillance imaging may identify recurrences in patients when they are more amenable to salvage therapy, resulting in superior 3-year SPFS, but given limited salvage options for children with recurrent ependymoma, the survival advantage of frequent surveillance imaging in asymptomatic patients remains ambiguous.

Comparison of Bispectral Index-Guided Individualized Anesthesia with Standard General Anesthesia on Inadequate Emergence and Postoperative Delirium in Elderly Patients Undergoing Esophagectomy: A Retrospective Study at a Single Center

Background

Elderly patients are susceptible to general anesthetics, with a higher bispectral index (BIS) at loss of consciousness (LOC) achieved by propofol infusion compared with young patients. Overexposure to general anesthetics can have adverse effects such as inadequate emergence and postoperative delirium (PD). This study aimed to compare the effects of BIS-guided individualized anesthesia with standard general anesthesia on emergence and delirium after esophagectomy.

Material/Methods

Data on 161 elderly patients undergoing esophagectomy for cancer were retrospectively obtained from electronic medical records. We performed propensity score matching analysis between patients receiving individualized anesthesia (BIS value maintained at about 10 less than the value at LOC) and those receiving standard anesthesia (BIS value maintained at 40–60). In addition, we conducted univariate and multivariate logistic analyses in the entire cohort.

Results

Patients receiving individualized anesthesia had higher BIS values and a lower propofol requirement during surgery than those receiving standard general anesthesia (P<0.05). The overall incidences of inadequate emergence and PD were 37.9% and 18.0% (n=161), respectively. Logistic regression analysis revealed that the independent risk factors for PD were organic brain disease (odds ratio [OR] 6.308; 95% confidence interval [CI] 2.458–16.187) and inadequate emergence (OR 4.063; 95% CI 1.645–10.033).

Conclusions

BIS-guided individualized anesthesia (lighter) does not reduce inadequate emergence or PD compared with standard general anesthesia in elderly patients undergoing esophagectomy. Independent risk factors for PD include organic brain disease and inadequate emergence.

Desoxyrhapontigenin attenuates neuronal apoptosis in an isoflurane-induced neuronal injury model by modulating the TLR-4/cyclin B1/Sirt-1 pathway

This study investigated the protective effect of desoxyrhapontigenin (DOP) against isoflurane (ISF)-induced neuronal injury in rats. Neuronal injury was induced in pups by exposing them to 0.75% ISF on postnatal day 7 with 30% oxygen for 6 h. The pups were treated with DOP 10 mg/kg, i.p., for 21 days after ISF exposure. The protective effect of DOP was estimated by assessing cognitive function using the neurological score and the Morris water maze. Neuronal apoptosis was assessed in the hippocampus using the TUNEL assay, and protein expression of caspase-3, Bax, and Bcl-2 was measured by Western blotting. The levels of cytokines and oxidative stress parameters were assessed by ELISA. Western blotting and RT-PCR were performed to measure the expression of NF-kB, TLR-4, Sirt-1, and cyclin B1 protein in the brain. The cognitive function and neurological function scores were improved in the DOP group compared with the ISF group. Moreover, DOP treatment reduced the number of TUNEL-positive cells and the expression of caspase-3, Bax, and Bcl-2 protein in the brains of rats with neuronal injury. The levels of mediators of inflammation and oxidative stress were reduced in the brain tissue of the DOP group. Treatment with DOP attenuated the protein expression of TLR-4, NF-kB, cyclin B1, and Sirt-1 in the brain tissue of rats with neuronal injury. In conclusion, DOP ameliorates neuronal apoptosis and improves cognitive function in rats with ISF-induced neuronal injury. Moreover, DOP treatment can prevent neuronal injury by regulating the TLR-4/cyclin B1/Sirt-1 pathway.

Short-term memory impairment in patients undergoing general anesthesia and its contributing factors

Background:

Short-term memory disorder following surgery and anesthesia is a common complication of anesthesia and a common complaint of the patients.

Aims:

This study was designed to assess memory impairment in patients undergoing elective surgery, investigate the effect of general anesthesia (GA) on memory, and identify the factors contributing to it, as well as the specific effect of anesthesia on each of the memory domains.

Setting and Design:

This cross-sectional study was performed in a university hospital.

Methods and Materials:

Patients with the American Society of Anesthesiologists (ASA) Class I, II, and III who were candidates for elective abdominal surgery were enrolled. Patients answered several questions based on the Wechsler Memory Scale–Revised V (WMS-R-V), a standardized questionnaire, minutes before entering the operating room (OR) and again after 24 h postoperation, and the differences were recorded.

Statistical Analysis:

Analysis was performed using T-independent and Chi-square tests with Pearson's coefficient and Fischer's exact test and Man–Whitney test. Data were analyzed using the Statistical Package for the Social Sciences (SPSS) software.

Results:

Four hundred patients (198 females and 202 males) with a mean age of 50.75 years were enrolled in our study. Our study results showed that short-term memory after GA was significantly decreased compared with preanesthesia (P < 0.05). There was no significant relationship between memory disorder following GA and gender (P = 0.18) or comorbidities (P = 0.138). However, older age was found to be a contributing factor to memory loss following GA (P < 0.001). The highest and lowest effect of GA were found on the number repeat (45.2%) and personal information (16.2%) domain of the memory.

Conclusion:

GA significantly reduces the patient's short-term memory after the surgery.

Cognitive Function in Kidney Transplantation

Purpose of the review

Cognitive impairment is common in kidney transplant recipients and affects quality of life, graft survival, morbidity, and mortality. In this review article we discuss the epidemiology, diagnosis, pathophysiology and future directions for cognitive impairment in kidney transplantation. We describe the potential role of pre-transplant cognition, immunosuppression and peri-transplant factors in post -transplant cognitive impairment.

Recent Findings

A majority of patients with kidney transplant have cognitive impairment. Cognitive impairment affects both pre-transplant evaluation and post-transplant outcomes. Failure to identify patients with cognitive impairment can withhold appropriate care and timely intervention.

Summary

Cognitive impairment is common in kidney transplant and affects outcomes. Studies addressing modifiable risk factors and possible interventions to slow cognitive decline in patients with kidney disease are needed.

THE IMPORTANCE OF NON-INVASIVE REGIONAL BRAIN OXIMETRY IN PREVENTING POSTOPERATIVE COGNITIVE DYSFUNCTION DURING LAPAROSCOPIC CHOLECYSTECTOMY IN ELDERLY AND SENILE PATIENTS

The adverse effect of general anesthesia in elderly patients during surgery requires monitoring of functions and processes to identify their dangerous abnormalities to prevent complications. The aim of the study. To establish the effectiveness of non-invasive regional brain oximetry with rSO2 determination during anesthetic support in laparoscopic cholecystectomy (LCE) to prevent postoperative cognitive dysfunction in elderly and senile patients. Material and methods. 84 elderly and senile patients with diagnosed gallstone disease, acute cholecystitis, who underwent LCE with sevofluran inhalational anesthesia and total intravenous anesthesia with propofol were examined. rSO2 was monitored. Cognitive functions were assessed using neuropsychological scales and the MMSE mental state examination scale. Results. rSO2 was found to be significantly decreased during the carbon dioxide insufflation as compared to before premedication: in LH (left hemisphere) – by 7.0 %, in RH (right hemisphere) – by 6.9 % (Group I); in LH – by 7.4 %, in RH – by 7.5 % (Group II). rSO2 was significantly increased during the surgery, particularly in the middle of the operation, as compared to before premedication: in LH – by 14.66 %, in RH – by 13.94 % (Group I); in LH – by 11.60 %, in RH – by 11.53 % (Group II). The day following the surgery, cognitive functions significantly decreased by 8.7 % on the Luria's test, by 6.0 % on the MMSE test (Group I); in Group II – by 10.1 % and 6.3 %, respectively, as compared to before premedication. On Day 5 after the surgery, cognitive functions decreased by 2.7 % on the Luria's test, by 0.35 % on the MMSE test (Group I); in Group II – by 2.7 % and 0.35 %, respectively, as compared to before premedication. Conclusions. A decrease in rSO2 can occur during LCE in the Trendelenburg position, despite the fact that other intraoperative indicators remain stable, which allows it to remain unrecognized. rSO2 monitoring in the perioperative period contributes to alertness and timely measures to prevent postoperative cognitive dysfunction.

General anesthesia affecting on developing brain: evidence from animal to clinical research

As the recent update of General anaesthesia compared to spinal anaesthesia (GAS) studies has been published in 2019, together with other clinical evidence, the human studies provided an overwhelming mixed evidence of an association between anaesthesia exposure in early childhood and later neurodevelopment changes in children. Pre-clinical studies in animals provided strong evidence on how anaesthetic and sedative agents (ASAs) causing neurotoxicity in developing brain and deficits in long-term cognitive functions. However pre-clinical results cannot translate to clinical practice directly. Three well designed large population-based human studies strongly indicated that a single brief exposure to general anesthesia (GAs) is not associated with any long-term neurodevelopment deficits in children's brain. Multiple exposure might cause decrease in processing speed and motor skills of children. However, the association between GAs and neurodevelopment in children is still inconclusive. More clinical studies with larger scale observations, randomized trials with longer duration exposure of GAs and follow-ups, more sensitive outcome measurements, and strict confounder controls are needed in the future to provide more conclusive and informative data. New research area has been developed to contribute in finding solutions for clinical practice as attenuating the neurotoxic effect of ASAs. Xenon and Dexmedetomidine are already used in clinical setting as neuroprotection and anaesthetic sparing-effect, but more research is still needed.

Sophoricoside attenuates neuronal injury and altered cognitive function by regulating the LTR-4/NF-κB/PI3K signalling pathway in anaesthetic-exposed neonatal rats

Introduction

This study examined the protective effects of sophoricoside on neuronal injury and cognitive dysfunction in anaesthetic-exposed neonatal rats.

Material and methods

Neuronal injury was induced in rat pups by exposure to isoflurane (0.75%) with 30% oxygen for 6 h on P7. The protective effects of sophoricoside were evaluated by assessing cognitive function using the neurological score and Morris water maze. Neuronal apoptosis was assessed in hippocampus tissue using a TUNEL assay. The cytokine and macrophage inflammatory protein levels were assessed by ELISA. Western blot assays and RT-PCR were performed to assess the expression of NF-κB, TLR-4, Akt, and PI3K proteins in neuronal tissues. Immunohistochemical and histopathological changes were observed in the brain tissues of isoflurane-induced neuronal injury rats.

Results

The sophoricoside treatment improved cognitive and neuronal function in rats exposed to isoflurane. Cytokine and MIP levels in the brain tissues of isoflurane-exposed rats decreased. However, sophoricoside treatment attenuated the expression of TLR-4, PI3K, and Akt protein in the brain tissues of isoflurane-exposed rats. The histopathology improved in the sophoricoside-treated isoflurane-exposed rats.

Conclusions

Sophoricoside treatment protects against neuronal injury and reduced cognitive function in isoflurane-induced neuronal injury rats by regulating TLR-4 signalling.