Early childhood general anaesthesia exposure and neurocognitive development

Rosiglitazone Promotes Oligodendrocyte Development and Myelin Formation of Repeated Neonatal Sevoflurane Exposure via PPARγ Signaling

Sevoflurane is one of the most commonly used general anesthetics for children and infants. Recent research indicates that repeated exposure to sevoflurane in neonates induces cognitive and fine motor deficits. Peroxisome proliferator-activated receptor-γ (PPARγ) agonists have garnered significant attention as potential therapies for a variety of neurological conditions. In this research, we evaluated whether pretreatment with rosiglitazone in neonatal mice could address myelination defects, cognitive impairment, and fine motor dysfunction via PPARγ. The mice were exposed to 3% sevoflurane for 2 h on postnatal days 6-8 (P6-P8). Behavioral tests were conducted from P29 to P34. Additionally, we evaluated morphological and functional changes related to myelin. Our results showed that rosiglitazone pretreatment significantly ameliorated the cognitive and fine motor impairments of repeated neonatal sevoflurane exposure. In addition, rosiglitazone pretreatment promoted oligodendrocyte precursor cells (OPCs) differentiation and myelination. This suggests that rosiglitazone may be used in clinical settings to enhance the security of neonatal sevoflurane exposure. Furthermore, PPARγ and fatty acid synthase (FASN) may be mediators for rosiglitazone, which alleviates myelination defects, cognitive impairment, and fine motor dysfunction.

Triggering Receptor Expressed on Myeloid Cells 2 Alleviated Sevoflurane-Induced Developmental Neurotoxicity via Microglial Pruning of Dendritic Spines in the CA1 Region of the Hippocampus

Sevoflurane induces developmental neurotoxicity in mice; however, the underlying mechanisms remain unclear. Triggering receptor expressed on myeloid cells 2 (TREM2) is essential for microglia-mediated synaptic refinement during the early stages of brain development. We explored the effects of TREM2 on dendritic spine pruning during sevoflurane-induced developmental neurotoxicity in mice. Mice were anaesthetized with sevoflurane on postnatal days 6, 8, and 10. Behavioral performance was assessed using the open field test and Morris water maze test. Genetic knockdown of TREM2 and overexpression of TREM2 by stereotaxic injection were used for mechanistic experiments. Western blotting, immunofluorescence, electron microscopy, three-dimensional reconstruction, Golgi staining, and whole-cell patch-clamp recordings were performed. Sevoflurane exposures upregulated the protein expression of TREM2, increased microglia-mediated pruning of dendritic spines, and reduced synaptic multiplicity and excitability of CA1 neurons. TREM2 genetic knockdown significantly decreased dendritic spine pruning, and partially aggravated neuronal morphological abnormalities and cognitive impairments in sevoflurane-treated mice. In contrast, TREM2 overexpression enhanced microglia-mediated pruning of dendritic spines and rescued neuronal morphological abnormalities and cognitive dysfunction. TREM2 exerts a protective role against neurocognitive impairments in mice after neonatal exposures to sevoflurane by enhancing microglia-mediated pruning of dendritic spines in CA1 neurons. This provides a potential therapeutic target in the prevention of sevoflurane-induced developmental neurotoxicity.

Ferritinophagy-Mediated Hippocampus Ferroptosis is Involved in Cognitive Impairment in Immature Rats Induced by Hypoxia Combined with Propofol

Propofol is a clinically common intravenous general anesthetic and is widely used for anesthesia induction, maintenance and intensive care unit (ICU) sedation in children. Hypoxemia is a common perioperative complication. In clinical work, we found that children with hypoxemia who received propofol anesthesia experienced significant postoperative cognitive changes. To explore the causes of this phenomenon, we conducted the study. In this study, our in vivo experiments found that immature rats exposed to hypoxia combined with propofol (HCWP) could develop cognitive impairment. We performed the RNA-seq analysis of its hippocampal tissues and found that autophagy and ferroptosis may play a role in our model. Next, we verified the participation of the two modes of death by detecting the expression of autophagy-related indexes Sequestosome 1 (SQSTM1) and Beclin1, and ferroptosis-related indicators Fe2+, reactive oxygen species (ROS) and glutathione peroxidase 4 (GPX4). Meanwhile, we found that ferrostatin-1 (Fer-1), an inhibitor of ferroptosis, could improve cognitive impairment in immature rats caused by HCWP. In addition, we found that nuclear receptor coactivator 4 (NCOA4)-mediated ferritinophagy, which acted as a key junction between autophagy and ferroptosis, was also involved. Finally, our in vitro experiments concluded that autophagy activation was an upstream factor in HCWP-induced hippocampus ferroptosis through the intervention of autophagy inhibitor 3-methyladenine (3-MA). Our study was expected to provide an attractive therapeutic target for cognitive impairment that occurred after HCWP exposures.

Long-term outcomes of early exposure to repeated general anaesthesia in children with cystic fibrosis (CF-GAIN): a multicentre, open-label, randomised controlled phase 4 trial

BACKGROUND

Long-term effects of early, recurrent human exposure to general anaesthesia remain unknown. The Australasian Cystic Fibrosis Bronchoalveolar Lavage (ACFBAL) trial provided an opportunity to examine this issue in children randomly assigned in infancy to either repeated bronchoalveolar-lavage (BAL)-directed therapy with general anaesthesia or standard care with no planned lavages up to 5 years of age when all children received BAL-directed therapy under general anaesthesia.

METHODS

This multicentre, randomised, open-label phase 4 trial (CF-GAIN) used the original ACFBAL trial randomisation at 3·6 months (SD 1·6) to BAL-directed therapy or standard-care groups to assess the impact of general anaesthesia exposures over early childhood. Children who completed the ACFBAL trial, with a mean age of 5·1 (SD 0·18) years, received standardised neurobehavioural and health-related-quality-of-life assessment and brain MRI scans between Oct 8, 2013, and June 30, 2017, at a mean age of 12·8 (SD 1·7) years at three hospitals in Australia and one hospital in New Zealand. The primary outcome was a composite score of performance on a standardised, computer-based assessment of child attention, processing speed, and response inhibition skills (Conners Continuous Performance test, second edition). Secondary outcomes included intellectual function, other neurobehavioural measures, and brain imaging as an exploratory outcome. The trial was registered with the Australian New Zealand Clinical Trials Registry (ACTRN 12613000057785) and is completed.

FINDINGS

At 2 years, the BAL-directed therapy group (n=52) and standard-care group (n=45) had a median of 2·0 (IQR 1·0-3·0) and 0·0 (0·0-0·0) exposures, respectively. At completion of the ACFBAL trial, the BAL-directed therapy group had a median of 6·0 (4·0-9·5) exposures and the standard-care group 2·0 (1·0-4·0) exposures. At CF-GAIN completion, the BAL-directed therapy group had a median of 10·0 (IQR 6·5-14·5) exposures and the standard-care group 4·0 (3·0-7·0) exposures. Cumulative general anaesthesia exposure time was not prospectively collected but, for those with complete cumulative exposure time data to the end of the ACFBAL trial, the median cumulative exposure time for the BAL-directed therapy group (n=29) was 180 (IQR 140-285) min and for the standard-care group (n=32) was 48 (30-122) min. The mean Conners Continuous Performance test, second edition composite score was 51 (SD 8·1) in BAL-directed therapy group and 53 (8·8) in the standard-care group; difference -1·7 (95% CI -5·2 to 1·7; p=0·32) with similar performance on other neurobehavioural measures, including measures of executive function, intellectual quotient scores, and brain imaging.

INTERPRETATION

Our findings suggest that repeated general anaesthesia exposure in young children with cystic fibrosis is not related to functional impairment in attention, intellectual quotient, executive function, or brain structure compared with a group with fewer and shorter cumulative anaesthesia durations.

FUNDING

National Health and Medical Research Council Australia, Queensland Government Health Service and Clinical Innovation Fellowship, and the Children's Hospital Foundation Queensland.

A systematic review on safety and surgical and anesthetic risks of elective abdominal laparoscopic surgery in infants to guide laparoscopic ovarian tissue harvest for fertility preservation for infants facing gonadotoxic treatment

Background

Infertility is an important late effect of childhood cancer treatment. Ovarian tissue cryopreservation (OTC) is established as a safe procedure to preserve gonadal tissue in (pre)pubertal girls with cancer at high risk for infertility. However, it is unclear whether elective laparoscopic OTC can also be performed safely in infants <1 year with cancer. This systematic review aims to evaluate the reported risks in infants undergoing elective laparoscopy regarding mortality, and/or critical events (including resuscitation, circulatory, respiratory, neurotoxic, other) during and shortly after surgery.

Methods

This systematic review followed the Preferred reporting Items for Systematic Review and Meta-Analyses (PRISMA) reporting guideline. A systematic literature search in the databases Pubmed and EMbase was performed and updated on February 15th, 2023. Search terms included 'infants', 'intubation', 'laparoscopy', 'mortality', 'critical events', 'comorbidities' and their synonyms. Papers published in English since 2000 and describing at least 50 patients under the age of 1 year undergoing laparoscopic surgery were included. Articles were excluded when the majority of patients had congenital abnormalities. Quality of the studies was assessed using the QUIPS risk of bias tool.

Results

The Pubmed and Embase databases yielded a total of 12,401 unique articles, which after screening on title and abstract resulted in 471 articles to be selected for full text screening. Ten articles met the inclusion criteria for this systematic review, which included 1778 infants <1 years undergoing elective laparoscopic surgery. Mortality occurred once (death not surgery-related), resuscitation in none and critical events in 53/1778 of the procedures.

Conclusion

The results from this review illustrate that morbidity and mortality in infants without extensive comorbidities during and just after elective laparoscopic procedures seem limited, indicating that the advantages of performing elective laparoscopic OTC for infants with cancer at high risk of gonadal damage may outweigh the anesthetic and surgical risks of laparoscopic surgery in this age group.

Translatome and transcriptome profiling of neonatal mice hippocampus exposed to sevoflurane anesthesia

Exposure to anesthesia in early life may cause severe damage to the brain and lead to cognitive impairment. The underlying mechanisms, which have only been investigated in a limited scale, remains largely elusive. We performed translatome and transcriptome sequencing together for the first time in hippocampus of neonatal mice that were exposed to sevoflurane. We treated a group of neonatal mice with 2.5 % sevoflurane for 2 h on day 6, 7, 8, 9 and treated another group on day 6, 7. We performed behavioral study after day 30 for both groups and the control to evaluate the cognitive impairment. On day 36, we collected translatome and transcriptome from the hippocampus in the two groups, compared the gene expression levels between the groups and the control, and validated the results with RT-qPCR. We identified 1750 differentially expressed genes (DEGs) from translatome comparison and 1109 DEGs from transcriptome comparison. As expected, translatome-based DEGs significantly overlapped with transcriptome-based DEGs, and functional enrichment analysis generated similar enriched cognition-related GO terms and KEGG pathways. However, for many genes like Hspa5, their alterations in translatome differed remarkably from those in transcriptome, and Western blot results were largely concordant with the former, suggesting that translational regulation plays a significant role in cellular response to sevoflurane. Our study revealed global alterations in translatome and transcriptome of mice hippocampus after neonatal exposure to sevoflurane anesthesia and highlighted the importance of translatome analysis in understanding the mechanisms responsible for anesthesia-induced cognitive impairment.

Inhalation exposure-induced toxicity and disease mediated via mTOR dysregulation

Environmental air pollution is a global health concern, associated with multiple respiratory and systemic diseases. Epidemiological supports continued urbanization and industrialization increasing the prevalence of inhalation exposures. Exposure to these inhaled pollutants induces toxicity via activation of numerous cellular mechanisms including oxidative stress, autophagy, disrupted cellular metabolism, inflammation, tumorigenesis, and others contributing to disease development. The mechanistic target of rapamycin (mTOR) is a key regulator involved in various cellular processes related to the modulation of metabolism and maintenance of homeostasis. Dysregulation of mTOR occurs following inhalation exposures and has also been implicated in many diseases such as cancer, obesity, cardiovascular disease, diabetes, asthma, and neurodegeneration. Moreover, mTOR plays a fundamental role in protein transcription and translation involved in many inflammatory and autoimmune diseases. It is necessary to understand inhalation exposure-induced dysregulation of mTOR since it is key regulator which may contribute to numerous disease processes. This mini review evaluates the available literature regarding several types of inhalation exposure and their impacts on mTOR signaling. Particularly we focus on the mTOR signaling pathway related outcomes of autophagy, lipid metabolism, and inflammation. Furthermore, we will examine the implications of dysregulated mTOR pathway in exposure-induced diseases. Throughout this mini review, current gaps will be identified related to exposure-induced mTOR dysregulation which may enable the targeting of mTOR signaling for the development of therapeutics.

Suberoylanilide hydroxamic acid attenuates cognitive impairment in offspring caused by maternal surgery during mid-pregnancy

Some pregnant women have to experience non-obstetric surgery during pregnancy under general anesthesia. Our previous studies showed that maternal exposure to sevoflurane, isoflurane, propofol, and ketamine causes cognitive deficits in offspring. Histone acetylation has been implicated in synaptic plasticity. Propofol is commonly used in non-obstetric procedures on pregnant women. Previous studies in our laboratory showed that maternal propofol exposure in pregnancy impairs learning and memory in offspring by disturbing histone acetylation. The present study aims to investigate whether HDAC inhibitor suberoylanilide hydroxamic acid (SAHA) could attenuate learning and memory deficits in offspring caused by maternal surgery under propofol anesthesia during mid-pregnancy. Maternal rats were exposed to propofol or underwent abdominal surgery under propofol anesthesia during middle pregnancy. The learning and memory abilities of the offspring rats were assessed using the Morris water maze (MWM) test. The protein levels of histone deacetylase 2 (HDAC2), phosphorylated cAMP response-element binding (p-CREB), brain-derived neurotrophic factor (BDNF), and phosphorylated tyrosine kinase B (p-TrkB) in the hippocampus of the offspring rats were evaluated by immunofluorescence staining and western blot. Hippocampal neuroapoptosis was detected by TUNEL staining. Our results showed that maternal propofol exposure during middle pregnancy impaired the water-maze learning and memory of the offspring rats, increased the protein level of HDAC2 and reduced the protein levels of p-CREB, BDNF and p-TrkB in the hippocampus of the offspring, and such effects were exacerbated by surgery. SAHA alleviated the cognitive dysfunction and rescued the changes in the protein levels of p-CREB, BDNF and p-TrkB induced by maternal propofol exposure alone or maternal propofol exposure plus surgery. Therefore, SAHA could be a potential and promising agent for treating the learning and memory deficits in offspring caused by maternal nonobstetric surgery under propofol anesthesia.

General Anesthesia Exposure in Infancy and Childhood: A 10-year Bibliometric Analysis

PURPOSE

Heated discussions have divided health care providers and policymakers on the risks versus benefits of general anesthesia in pediatric populations. We conducted this study to provide a comprehensive bibliometric analysis of general anesthesia in this specific population over the past decade.

DESIGN

We summarized and quantitatively analyzed the studies related to general anesthesia in children and infants over the past decade.

METHODS

Using the Web of Science Core Collection as the data source, we analyzed the literature using CiteSpace software, focusing on authors, countries, institutions, keywords, and references to identify hotspots and predict research trends.

FINDINGS

A total of 2,364 publications on pediatric anesthesia were included in the analysis. The number of related publications and citations steadily increased from 2013 to 2022. The United States was the leading country in terms of output, and University of Toronto was the primary contributing institution. Co-citation analysis revealed that over the past decade research has mainly focused on the long-term adverse effects of general anesthesia on neurodevelopment and acute perioperative crisis events. Keyword analysis identified infant sedation and drug selection and compatibility as promising areas for development. In addition, improving the quality of perioperative anesthesia will be a major research focus in the future.

CONCLUSIONS

Recent research in pediatric anesthesia has focused on mitigating the adverse effects of general anesthesia in infants and young children and studying the pharmacological compatibility of anesthetics. Our study results would assist researchers and clinicians in understanding the current research status and optimizing clinical practice in this field.

Sevoflurane causes cognitive impairment by inducing iron deficiency and inhibiting the proliferation of neural precursor cells in infant mice

AIMS

Numerous studies on animals have shown that exposure to general anesthetics in infant stage may cause neurocognitive impairment. However, the exact mechanism is not clear. The dysfunction of iron metabolism can cause neurodevelopmental disorders. Therefore, we investigated the effect of iron metabolism disorder induced by sevoflurane (Sev) on cognitive function and the proliferation of neural precursor cells (NPCs) and neural stem cells (NSCs) in infant mice.

METHODS

C57BL/6 mice of postnatal day 14 and neural stem cells NE4C were treated with 2% Sev for 6 h. We used the Morris water maze (MWM) to test the cognitive function of infant mice. The proliferation of NPCs was measured using bromodeoxyuridine (BrdU) label and their markers Ki67 and Pax6 in infant brain tissues 12 h after anesthesia. Meanwhile, we used immunohistochemical stain, immunofluorescence assay, western blot, and flow cytometer to evaluate the myelinogenesis, iron levels, and cell proliferation in cortex and hippocampus or in NE4C cells.

RESULTS

The results showed that Sev significantly caused cognitive deficiency in infant mice. Further, we found that Sev inhibited oligodendrocytes proliferation and myelinogenesis by decreasing MBP and CC-1 expression and iron levels. Meanwhile, Sev also induced the iron deficiency in neurons and NSCs by downregulating FtH and FtL expression and upregulating the TfR1 expression in the cortex and hippocampus, which dramatically suppressed the proliferation of NSCs and NPCs as indicated by decreasing the colocalization of Pax6+ and BrdU+ cells, and caused the decrease in the number of neurons. Interestingly, iron supplementation before anesthesia significantly improved iron deficiency in cortex and hippocampus and cognitive deficiency induced by Sev in infant mice. Iron therapy inhibited the decrease of MBP expression, iron levels in neurons and oligodendrocytes, and DNA synthesis of Pax6+ cells in hippocampus induced by Sev. Meanwhile, the number of neurons was partially recovered in hippocampus.

CONCLUSION

The results from the present study demonstrated that Sev-induced iron deficiency might be a new mechanism of cognitive impairment caused by inhaled anesthetics in infant mice. Iron supplementation before anesthesia is an effective strategy to prevent cognitive impairment caused by Sev in infants.

Risk of attention deficit hyperactivity disorder diagnosis following multiple exposures to general anesthesia in the paediatric population: A systematic review and meta-analysis

Objectives

The risk of attention deficit hyperactivity disorder (ADHD) following multiple exposures to anesthesia has been debated. Our objective was to systematically review the literature to examine the association between multiple exposures to general anesthesia before age 5 and subsequent diagnosis of ADHD.

Methods

A systematic search of EMBASE, PubMed, and SCOPUS was performed using key search terms in February 2022. We included studies that: were published after 1980, included only otherwise healthy children who experienced two or more exposures to general anesthetic before age 5, diagnosed ADHD by a medical professional before age 19 years after exposure to general anesthetic, were cross-sectional, case-control, or cohort study, and were published in English. The results (expressed as hazard ratios [HR] and associated 95% confidence intervals [CI]) were pooled using meta-analytic techniques. Studies which did not present their results as HR and 95% CI were analyzed separately. GRADE was used to determine the certainty of the findings. PRISMA guidelines were followed at each stage of the review.

Results

Eight studies (196,749 children) were included. Five reported HR and 95% CI and were subsequently pooled for meta-analysis. Multiple exposures to anesthesia were associated with diagnosis of ADHD before the 19th year of life (HR: 1.71; 95% CI: 1.59, 1.84). Two of the three studies not used in the meta-analysis also found an increased risk of ADHD diagnosis following multiple anesthetic exposures.

Conclusions

There was an association between multiple early exposures to general anesthesia and later diagnosis of ADHD.

Characterization of infant spinal anesthesia using surface electromyography: An observational study

BACKGROUND

As the risks of general anesthesia in infants become clearer, pediatric anesthesiologists are seeking alternatives. Though infant spinal anesthesia is one such alternative, its use is limited by its perceived short duration. Prior studies investigating infant spinal anesthesia are open to interpretation and may not have accurately characterized block onset or density. Surface electromyography is a passive, noninvasive modality that can measure the effects of neural blockade.

AIMS

To quantitatively describe the onset, density, and duration of infant spinal anesthesia using surface electromyography.

METHODS

In this observational study, 13 infants undergoing lower abdominal surgery received spinal anesthesia (0.5% bupivacaine with clonidine). Surface electromyography collected continuous data at T2, right T8, left T8, and L2. Data were processed in MATLAB. Onset, density, and duration were defined as the mean derivative within the first 30 s after block administration, the maximum difference in signal compared with preblock baseline, and the time elapsed between block administration and the return of a persistent signal to 50% above the maximum difference, respectively.

RESULTS

Mean patient age and weight were 7.5 ± 2.6 months and 8.0 ± 2.2 kg, respectively. All patients were male. There was a statistically significant difference in the average rate of spinal anesthesia onset (mean percent decrease per second [95% confidence interval]) between myotomes (F (3, 35) = 7.42, p < .001): T2 = 15.93 (9.23, 22.62), right T8 = 20.98 (14.52, 27.44), left T8 = 17.92 (11.46, 24.38), L2 = 32.92 (26.46, 39.38). There was a statistically significant difference in mean surface electromyography signal (mean decibels, 95% confidence interval) across both pre- and postspinal anesthesia Timepoints between myotomes (F (3, 36) = 32.63, p < .0001): T2 = 45.05 (38.92, 51.18), Right T8 = 41.26 (35.12, 47.39), Left T8 = 43.07 (36.93, 49.20), L2 = 22.79 (16.65, 28.92). Within each myotome, there was statistically significant, near complete attenuation of sEMG signal due to spinal anesthesia: T2 mean (pre-post) difference: mean decibels (95% confidence interval) = 39.53 (28.87, 50.20), p < .0001, right T8 = 51.97 (41.30, 62.64), p < .0001, left T8 = 46.09 (35.42, 56.76), p < .0001, L2 = 44.75 (34.08, 55.42), p < .0001. There was no statistically significant difference in mean (pre-post) differences between myotomes. The mean duration of spinal anesthesia lasted greater than 90 min and there was no statistical difference between myotomes. There were also no statistically significant associations between age and weight and onset or duration.

CONCLUSIONS

Surface electromyography can be used to characterize neural blockade in children. Importantly, these results suggest that awake infant spinal anesthesia motor block lasts, conservatively, 90 min. This exploratory study has highlighted the potential for expanding awake infant spinal anesthesia to a broader range of procedures and the utility of surface electromyography in studying regional anesthesia techniques.

7,8-Dihydroxyflavone ameliorates cognitive impairment induced by repeated neonatal sevoflurane exposures in mice through increasing tau O-GlcNAcylation

BACKGROUND

Sevoflurane, one of the most commonly used general anesthetics for pediatric anesthesia, has recently gained significant attention in both preclinical and clinical settings due to its potential neurotoxicity in the developing brain. Tau phosphorylation, induced by sevoflurane, is recognized as one of the major causes of neurotoxicity. 7,8-dihydroxyflavone (DHF), a TrkB receptor agonist, has been reported to exhibit potential neuroprotective effects against tauopathies. In this study, our objective was to investigate whether DHF could provide neuroprotective effects against sevoflurane-induced neurotoxicity and explore the underlying molecular mechanisms.

METHODS

Six-day-old mice were subjected to 2 h of anesthesia with 3 % sevoflurane, with or without pretreatment of DHF (5 mg/kg/day, i.p.) for 3 consecutive days. Autonomic motor ability was assessed by open-field test, while learning and memory abilities were evaluated by the fear conditioning test. Western blotting was conducted to measure the levels of t-TrkB, p-TrkB, tau, and phosphorylated tau. Additionally, a co-immunoprecipitation assay was performed to investigate the interaction between O-GlcNAcylation and tau.

RESULTS

Repeated neonatal sevoflurane exposures resulted in reduced freezing time during the context and cued fear conditioning tests in adulthood. However, pretreatment with DHF restored the freezing time to the level of the control group, indicating that DHF effectively alleviated cognitive impairments induced by neonatal sevoflurane exposure. We also observed that repeated neonatal sevoflurane exposures increased tau phosphorylation while decreasing tau O-GlcNAcylation. However, DHF pretreatment rebalanced the tau O-GlcNAcylation/phosphorylation ratio by enhancing the interaction between tau and O-GlcNAcylation.

CONCLUSION

Our findings demonstrate that DHF effectively ameliorates sevoflurane-induced cognitive impairment in developing mice by restoring the balance between tau O-GlcNAcylation and phosphorylation. Therefore, this study suggests that DHF has the potential to be a therapeutic agent for treating cognitive impairment associated with anesthetics, such as sevoflurane.

Impact of Repeated Infantile Exposure to Surgery and Anesthesia on Gut Microbiota and Anxiety Behaviors at Age 6-9

(1) Background: Preclinical as well as population studies have connected general anesthesia and surgery with a higher risk of abnormal cognitive development, including emotional development. Gut microbiota dysbiosis in neonatal rodents during the perioperative period has been reported, however, the relevance of this to human children who undergo multiple anesthesia for surgeries is unknown. Given the emerging role of altered gut microbes in propagating anxiety and depression, we sought to study whether repeated infantile exposures to surgery and anesthesia affect gut microbiota and anxiety behaviors later in life. (2) Methods: This is a retrospectively matched cohort study comparing 22 pediatric patients of less than 3 years of age with multiple exposures (≥3) to anesthesia for surgeries and 22 healthy controls with no history of exposure to anesthesia. The parent report version of the Spence Children's Anxiety Scale (SCAS-P) was applied to evaluate anxiety in children aged between 6 and 9 years old. Additionally, the gut microbiota profiles of the two groups were compared using 16S rRNA gene sequencing. (3) Results: In behavioral tests, the p-SCAS score of obsessive compulsive disorder and social phobia were significantly higher in children with repeated anesthesia exposure relative to the controls. There were no significant differences between the two groups with respect to panic attacks and agoraphobia, separation anxiety disorder, physical injury fears, generalized anxiety disorder, and the total SCAS-P scores. In the control group, 3 children out of 22 were found to have moderately elevated scores, but none of them had abnormally elevated scores. In the multiple-exposure group, 5 children out of 22 obtained moderately elevated scores, while 2 scored as abnormally elevated. However, no statistically significant differences were detected in the number of children with elevated and abnormally elevated scores. The data show that repeated anesthesia and surgical exposures in children led to long-lasting severe gut microbiota dysbiosis. (4) Conclusions: In this preliminary study, our findings demonstrated that early repeated exposures to anesthesia and surgical predisposes children to anxiety as well as long-term gut microbiota dysbiosis. We should confirm these findings in a larger data population size and with detailed analysis. However, the authors cannot confirm an association between the dysbiosis and anxiety.

Maternal sevoflurane exposure induces neurotoxicity in offspring rats via the CB1R/CDK5/p-tau pathway

Sevoflurane is widely used for maternal anesthesia during pregnancy. Sevoflurane exposure of rats at mid-gestation can cause abnormal development of the central nervous system in their offspring. Sevoflurane is known to increase the expression of cannabinoid 1 receptor (CB1R) in the hippocampus. However, the effect of cannabinoid 1 receptor on fetal and offspring rats after maternal anesthesia is still unclear. At gestational day 14, pregnant rats were subjected to 2-h exposure to 3.5% sevoflurane or air. Rats underwent intraperitoneal injection with saline or rimonabant (1 mg/kg) 30 min prior to sevoflurane or air exposure. cannabinoid 1 receptor, cyclin-dependent kinase 5 (CDK5), p35, p25, tau, and p-tau expression in fetal brains was measured at 6, 12, and 24 h post-sevoflurane/air exposure. Neurobehavioral and Morris water maze tests were performed postnatal days 3-33. The expression of cannabinoid 1 receptor/cyclin-dependent kinase 5/p-tau and histopathological staining of brain tissues in offspring rats was observed. We found that a single exposure to sevoflurane upregulated the activity of cyclin-dependent kinase 5 and the level of p-tau via cannabinoid 1 receptor. This was accompanied by the diminished number of neurons and dendritic spines in hippocampal CA1 regions. Finally, these effects induced lower scores and platform crossing times in behavioral tests. The present study suggests that a single exposure to 3.5% sevoflurane of rats at mid-gestation impairs neurobehavioral abilities and cognitive memory in offspring. cannabinoid 1 receptor is a possible target for the amelioration of postnatal neurobehavioral ability and cognitive memory impairments induced by maternal anesthesia.

General anaesthesia for photodynamic therapy of port-wine stain in children: A retrospective study

AIMS

This report intended to assess the safety and efficiency of general anaesthesia with preserved spontaneous breathing for pain management in photodynamic therapy (PDT) of port-wine stains (PWS) in paediatric patients.

METHODS

This study included 1960 Hemoporfin PDT procedures performed under general anaesthesia on 560 PWS patients. Medical records were retrospectively analysed. All of the procedures performed under general anaesthesia with preserved spontaneous breathing.

RESULTS

The patients comprised males (43.93%) and females (56.07%). Ninety percent of cases were ASA class I, and 10% were class II, no case was class III or higher. Adverse events accompanying general anaesthesia included postoperative irritability (8.98%), carbon dioxide pressure (PCO₂) >50 mmHg (15.97%), movement during surgery (6.98%), vomiting (0.2%), laryngospasm (0.2%), unplanned endotracheal intubation (0.05%), upper airway obstruction (0.05%), and hypoxia (0.1%). The FLACC score was <4 points in 84% of cases and 4∼6 points in 16% of cases.

CONCLUSIONS

General anaesthesia with preserved spontaneous breathing has few complications and appears safe and feasible for PDT in most children with PWS.

Computed Analysis of Retinal Vascular Growth After Bevacizumab Treatment of Retinopathy of Prematurity Until Age 3 Years

PURPOSE

Premature infants, after anti-vascular endothelial growth factor injections for retinopathy of prematurity, have persistent peripheral avascular retina (PAR). PAR is ablated with laser; however, physiologic growth of the retinal vasculature in the long term has not been measured. The purposes of this study were to measure retinal vessel growth after treatment with intravitreal bevacizumab (IVB) for retinopathy of prematurity, using serial fluorescein angiography (FA), until age 3 years, and to assess the timing for providing laser ablation in PAR.

METHODS

Data from an observational, longitudinal clinical study were collected. Angiographic images of eyes treated with IVB were included; imaging data from laser photocoagulation were excluded. All eyes underwent initial examination under general anesthesia with FA and photographic imaging. The retinal vessel length was measured from the temporal margin of the optic disc passing through the foveal center, and the lengths at subsequent FA were compared. To compare the changes in retinal vessel length over time in individual eyes, a paired-sample t test was performed.

FINDINGS

FA images from 70 eyes (35 infants) treated with IVB were available. A total of 150 FA images were available for review; data from 125 images of good quality were used for analysis. The mean postmenstrual ages (PMAs) at first, second, third, and fourth FA were 66.2, 100.9, 135.1, and 180.7 weeks, respectively. The mean retinal vessel length was 14.177 mm at first FA and 13.199 mm at fourth FA (PMA range, 42...234 weeks). Retinal vascular lengths of individual eyes compared over time showed no statistically significant growth from the first FA to age 3 years. The changes in retinal vessel length from first to second FA were -0.117 ± 0.79 mm (p = 0.42; n = 30); from first to third FA, +0.060 ± 0.85 mm (p = 0.79; n = 15); and first to fourth FA, -0.404 ± 1.32 mm (p = 0.45; n = 7).

IMPLICATIONS

Beyond 65 weeks' PMA, no meaningful retinal vascular growth occurred after IVB up to age 3 years, guiding the timing for physicians if laser photocoagulation is being considered. Future studies are needed to address retinal growth changes in the growing eyes of infants.

Lin28A Reduced Sevoflurane-Induced Nerve Injury and Cognitive Dysfunction by Inhibiting Tau Acetylation and Phosphorylation via Activating SIRT1 in Elderly Rats

Sevoflurane (Sev) might cause neurotoxicity in elderly rats. However, the role of Lin28A in Sev-induced neurotoxicity remains unclear in elderly rats. In this study, elderly rats were used to construct an Sev-induced nerve injury model. Learning and memory abilities were assessed by Morris water maze (MWM) trainings; pathological alterations in hippocampal region were assessed by HE staining; neuronal apoptosis was assessed by TUNEL; related protein expression was analyzed by immunofluorescence, immunohistochemistry, and Western blotting. Results of this study showed that Sev treatment caused nerve injury and cognitive dysfunction in elderly rats, with increased neuronal apoptosis and decreased Lin28A levels. Pathological impairment and learning and memory abilities of elderly rats were significantly improved after forced overexpression of Lin28A using AAV, accompanied by decreased expression of CD68, Iba-1, and GFAP. TUNEL analysis showed that Lin28A overexpression significantly reversed Sev-induced neuronal apoptosis. Further mechanistic analysis showed that Lin28A significantly promoted SIRT1 expression, which further reversed Sev-induced Tau acetylation at lysine 280 and 686 and Tau hyperphosphorylation, thereby alleviating nerve injury and cognitive dysfunction in elderly rats. The introduction of SIRT1 inhibitor EX527 further confirmed the involvement of SIRT1 in the regulation of Lin28A in elderly rats. In conclusion, our findings demonstrated that Lin28A reduced sevoflurane-induced nerve injury and cognitive dysfunction by inhibiting Tau acetylation and phosphorylation via activating SIRT1 in elderly rats.

Anesthesia and developing brain: What have we learned from recent studies

Anesthesia is unavoidable in surgical procedures. However, whether the general anesthetics are neurotoxic to immature brains remains undefined. Neurodevelopmental impairment induced by anesthesia has been a critical health issue and topic of concern. This review summarizes recent progress made in clinical and preclinical studies to provide useful suggestions and potential therapeutic targets for the protection of the immature brain. On the one hand, clinical researchers continue the debate about the effect of single and multiple exposures to anesthesia on developing brains. On the other hand, preclinical researchers focus on exploring the mechanisms of neurotoxic effects of general anesthesia on immature brains and seeking novel solutions. Rodent models have always been used in preclinical studies, but it is still unclear whether the mechanisms observed in rodent models have clinical relevance. Compared with these models, non-human primates (NHPs) are more genetically similar to humans. However, few research institutions in this area can afford to use NHP models in their studies. One way to address both problems is by combining single-cell sequencing technologies to screen differential gene expression in NHPs and perform in vivo validation in rodents. The mechanism of anesthesia-induced neurotoxicity still requires further elucidation in primates.

RIPK1/RIPK3-Mediated Necroptosis is Involved in Sevoflurane-Induced Neonatal Neurotoxicity in the Rat Hippocampus

Recent studies have shown that exposure to sevoflurane in developing brains causes neuronal apoptosis and cognitive dysfunction. "Necroptosis" is a novel pathway of necrosis. We introduced the caspase-specific inhibitor Z-VAD in addition to the receptor-interacting protein kinase 1 (RIPK1) inhibitor Nec-1, to ascertain the existence and importance of necroptosis. Sprague-Dawley rat pups postnatal day 7 were randomly assigned into one of five groups: control, sevoflurane + Z-VAD, sevoflurane + Nec-1, sevoflurane + Z-VAD + Nec-1 and 3% sevoflurane group. Neuronal apoptosis was evaluated by hematoxylin and eosin staining. The MTT assay was performed to evaluate cell viability. Immunofluorescence was employed to measure expression of RIPK1 and RIPK3. Western blots showing expression of RIPK1, RIPK3 and phosphorylation of mixed lineage kinase domain-like (p-MLKL) were used to explore the role of necroptosis. Binding of RIPK1/RIPK3 was detected via co-immunoprecipitation. Finally, the Morris water maze test was used to determine cognitive function. Exposure to 3% sevoflurane for 6 h induced neurotoxicity and inhibited cell viability. Neuron viability was low in the SEV, SEV + Z-VAD and SEV + Nec-1 groups. The study revealed that RIPK1 and RIPK3 protein expression increased significantly, but there was no significant differences between the SEV and SEV + Z-VAD groups. The expression of p-MLKL significantly increased in the SEV and SEV + Z-VAD groups, but not in the SEV + Nec-1 group or SEV + Z-VAD + Nec-1 group compared to the control group. Co-immunoprecipitation results showed that sevoflurane exposure enhanced binding of RIPK1/RIPK3 protein significantly. Blockade of apoptosis and necroptosis alleviated sevoflurane-induced cognitive impairment. Sevoflurane exposure elicited neurotoxicity within neonatal hippocampal neurons and tissues. Blockade of apoptosis or necroptosis alone did not attenuate sevoflurane-induced neurotoxicity (SIN). RIPK1/RIPK3-mediated necroptosis was involved in SIN in hippocampal neurons. SIN could be attenuated only by inhibiting both apoptosis and necroptosis.

Anaesthesia Challenges in a Neonate Having Supracardiac Total Anomalous Pulmonary Venous Return With Incidental Stridor for Non-operating Room Anaesthesia (NORA): Feed and Wrap Technique as a Rescue

This case represents anaesthetic challenges while managing a neonate having a congenital cardiac anomaly with incidental stridor for the non-operating room anaesthesia (NORA). Anaesthesia management of neonates is demanding even for experienced anaesthetists in terms of vascular access, airway management, relatively poor respiratory reservoir and transitional cardiac physiology. Neonate having cyanotic congenital heart disease with abnormal cardiac physiology demands further attention. In children with congenital heart disease, difficult intubation remains a possibility as they are more often associated with airway anomalies. NORA has its own set of anaesthesia challenges related to a lack of adequate anaesthesia equipment and monitoring devices, a limited and unfamiliar workspace, lack of trained support staff along with more medically complex patients. Recently there has been concern regarding the safety of anaesthetic agents in children < 3 years. So, techniques are being developed to promote immobilisation without using anaesthesia in short procedures. One such technique is the "feed and wrap" technique where feeding and swaddling induce natural sleep in infants. Here, we have used the "feed and wrap technique" in a 24-day-old neonate having supracardiac total anomalous pulmonary venous return with incidental stridor posted for contrast-enhanced computed tomography angiography.

Sevoflurane exposure may cause dysplasia of dendritic spines and result in fine motor dysfunction in developing mouse through the PI3K/AKT/mTOR pathway

Sevoflurane has become one of the most widely used volatile anesthetics in pediatric surgery. However, sevoflurane exposure may interfere with dendritic development and synaptogenesis, resulting in brain function impairment. The PI3K/AKT/mTOR pathway plays an important role in dendritic development and synaptic plasticity. Here we investigated whether sevoflurane exposure would affect the morphological proportions of dendritic spines in developing mouse and explored the role of the change of plasticity of dendritic spines in sevoflurane-induced neurodevelopmental toxicity. The related signaling pathway was also examined. C57BL/6 mice at postnatal day (PND) 7 were exposed to 2% sevoflurane for 3 h. The PI3k/AKT/mTOR agonist IGF-1 or the mTOR phosphorylation inhibitor KU0063794 was intraperitoneally injected 30 min before sevoflurane or O₂ exposure at PND7. Hippocampi were harvested 6 h after sevoflurane exposure. Western blotting was applied to measure the protein expression of PI3K/AKT/mTOR pathway phosphorylation. At PND14, brains from all groups were harvested for Golgi staining, and the morphology of dendritic spines of hippocampal neurons was observed by an oil immersion lens. When the mice grew to adolescence (PND48), fine motor function was measured by the Beam walking test. Here we showed that exposure to 2% sevoflurane for 3 h decreased the proportion of thin dendritic spines and increased the proportion of mushroom dendritic spines, but not changed the density of the dendritic spines. Sevoflurane exposure also suppressed the phosphorylation of the PI3K/AKT/mTOR pathway in immature mice hippocampi, and eventually led to long-term fine motor dysfunction. Meanwhile, IGF-1 pretreatment could rescue and KU0063794 pretreatment could aggravate the impairment induced by sevoflurane. In conclusion, sevoflurane exposure may cause a change of proportions of the types of dendritic spines through impacting the phosphorylation expression of the PI3K/AKT/mTOR pathway, and eventually led to long-term fine motor dysfunction in developing mouse.

PHLDA1 promotes sevoflurane-induced pyroptosis of neuronal cells in developing rats through TRAF6-mediated activation of Rac1

Sevoflurane anesthesia induces neurocognitive impairment and pyroptosis in the developing brain. Pleckstrin homology-like domain, family A, member 1 (PHLDA1) was involved in neuronal apoptosis, oxidative stress and inflammation during ischemic stroke. The role of PHLDA1 in sevoflurane-induced pyroptosis in developing rats was investigated. Firstly, neonatal rats at day 7 was exposed to 2.0% sevoflurane for 6 h to induce neurotoxicity. Pathological analysis showed that sevoflurane anesthesia induced hippocampal injury and reduced the number of neurons. The expression of PHLDA1 was elevated in hippocampus of sevoflurane-treated rats. Secondly, sevoflurane anesthesia-treated neonatal rats were injected with adeno-associated virus serotype (AAV) to mediate knockdown of PHLDA1. Injection with AAV-shPHLDA1 ameliorated sevoflurane-induced hippocampal injury and neurocognitive impairment in rats. Moreover, knockdown of PHLDA1 increased the number of neurons in sevoflurane-treated rats. Silence of PHLDA1 suppressed neuronal apoptosis, and inhibited pyroptosis in sevoflurane-treated rats. Thirdly, PHLDA1 was also elevated in sevoflurane-treated primary neuronal cells. Loss of PHLDA1 also enhanced cell viability and suppressed pyroptosis of sevoflurane-treated primary neuronal cells. Lastly, silence of PHLDA1 reduced protein expression of TRAF6 and p-Rac1 in sevoflurane-treated rats and neuronal cells. Over-expression of TRAF6 attenuated PHLDA1 silence-induced increase of cell viability and decreased pyroptosis in neuronal cells. In conclusion, loss of PHLDA1 protected against sevoflurane-induced pyroptosis in developing rats through inhibition of TRAF6-mediated activation of Rac1.

Predictors and occurrence of postoperative cognitive dysfunction in children undergoing noncardiac surgery: A prospective cohort study

In children after cardiac surgery, alterations in cognitive ability and behavior are increasingly common, but whether postoperative cognitive dysfunction (POCD) occurs in children undergoing noncardiac surgery is not known. The present study was performed to investigate the incidence rate and potential risk factors of early neurocognitive dysfunction in children after noncardiac surgery. Two hundred patients aged between 4 and 14 years old underwent elective noncardiac surgery and 100 healthy age-matched controls were enrolled in this prospective observational study. Wechsler Preschool and Primary Scale of Intelligence or Wechsler Intelligence Scale for Children-Revised were conducted 1 day before and 3 days after surgery. POCD was calculated and diagnosed as a combined Z score. Any factors that differed between POCD and non-POCD group (p < 0.10) were tested together by multivariate logistic regression analysis against the cognitive outcome of patients, to find out the independent risk factors of POCD. The general incidence of POCD was 15.6%. The univariate analysis revealed that POCD was associated with general anesthesia, surgical and anesthesia duration, early postoperative fever (EPF), and surgical history. However, only the history of surgery (p = 0.029), anesthesia duration (p = 0.010), and EPF (p < 0.001) were demonstrated to be independent risk factors for POCD. The occurrence rate of early POCD after noncardiac surgery in children is 15.6%. Children who had surgical history, longer anesthesia duration, or EPF are more prone to develop POCD.

The impact of early exposure to general anesthesia on visual and neurocognitive development

Every year millions of children are exposed to general anesthesia while undergoing surgical and diagnostic procedures. In the field of ophthalmology, 44,000 children are exposed to general anesthesia annually for strabismus surgery alone. While it is clear that general anesthesia is necessary for sedation and pain minimization during surgical procedures, the possibility of neurotoxic impairments from its exposure is of concern. In animals there is strong evidence linking early anesthesia exposure to abnormal neural development. but in humans the effects of anesthesia are debated. In humans many aspects of vision develop within the first year of life, making the visual system vulnerable to early adverse experiences and potentially vulnerable to early exposure to general anesthesia. We attempt to address whether the visual system is affected by early postnatal exposure to general anesthesia. We first summarize key mechanisms that could account for the neurotoxic effects of general anesthesia on the developing brain and review existing literature on the effects of early anesthesia exposure on the visual system in both animals and humans and on neurocognitive development in humans. Finally, we conclude by proposing future directions for research that could address unanswered questions regarding the impact of general anesthesia on visual development.

Sevoflurane-Induced Neurotoxicity in the Developing Hippocampus via HIPK2/AKT/mTOR Signaling

Sevoflurane (Sev) is a widely used inhalational anesthetic for general anesthesia in children. Previous studies have confirmed that multiple exposures to inhaled anesthetic can induce long-term neurotoxicity in newborn mice. However, the underlying mechanisms remain elusive. In this study, we investigated the role of homeodomain interacting protein kinase 2 (HIPK2), a stress activating kinase involved in neural survival and synaptic plasticity, and its underlying mechanism in sevoflurane-induced neurotoxicity. Empirical study showed that neuronal apoptosis was elevated after exposure to sevoflurane. Meanwhile, up-regulation of HIPK2 and AKT/mTOR signaling was observed in primary hippocampal neurons and hippocampus in mice upon anesthetic exposure. A64, antagonist of HIPK2, could significantly reduce increased apoptosis and activation of AKT/mTOR induced by sevoflurane. AKT antagonist MK2206 partially alleviated neuronal apoptosis without affecting the expression of HIPK2. Experimental results demonstrated a crucial role of HIPK2/AKT/mTOR signaling in neurotoxicity of sevoflurane. Thus, HIPK2/AKT/mTOR signaling can serve as a potential target for the protection of inhalation anesthesia-induced cytotoxicity in the future.

Differential Effects of Sevoflurane Exposure on Long-Term Fear Memory in Neonatal and Adult Rats

It remains unclear whether exposure to sevoflurane produces different effects on long-term cognitive function in developing and mature brains. In the present study, Sprague-Dawley neonatal rats at postnatal day (PND) 7 and adult rats (PND 56) were used in all experiments. We performed fear conditioning testing to examine long-term fear memory following 4-h sevoflurane exposure. We assessed hippocampal synapse ultrastructure with a transmission electron microscope. Moreover, we investigated the effect of sevoflurane exposure on the expression of postsynaptic protein 95 (PSD-95) and its binding protein kalirin-7 in the hippocampus. We observed that early exposure to sevoflurane in neonatal rats impairs hippocampus-dependent fear memory, reduces hippocampal synapse density, and dramatically decreases the expressions of PSD-95 and kalirin-7 in the hippocampus of the developing brain. However, sevoflurane exposure in adult rats has no effects on hippocampus-dependent fear memory and hippocampal synapse density, and the expressions of PSD-95 and kalirin-7 in the adult hippocampus are not significantly altered following sevoflurane treatment. Our results indicate that sevoflurane exposure produces differential effects on long-term fear memory in neonatal and adult rats and that PSD-95 signaling may be involved in the molecular mechanism for early sevoflurane exposure-caused long-term fear memory impairment.

Application of Nonhuman Primate Models in the Studies of Pediatric Anesthesia Neurotoxicity

Numerous animal models have been used to study developmental neurotoxicity associated with short-term or prolonged exposure of common general anesthetics at clinically relevant concentrations. Pediatric anesthesia models using the nonhuman primate (NHP) may more accurately reflect the human condition because of their phylogenetic similarity to humans with regard to reproduction, development, neuroanatomy, and cognition. Although they are not as widely used as other animal models, the contribution of NHP models in the study of anesthetic-induced developmental neurotoxicity has been essential. In this review, we discuss how neonatal NHP animals have been used for modeling pediatric anesthetic exposure; how NHPs have addressed key data gaps and application of the NHP model for the studies of general anesthetic-induced developmental neurotoxicity. The appropriate application and evaluation of the NHP model in the study of general anesthetic-induced developmental neurotoxicity have played a key role in enhancing the understanding and awareness of the potential neurotoxicity associated with pediatric general anesthetics.

Do We Have Viable Protective Strategies against Anesthesia-Induced Developmental Neurotoxicity?

Since its invention, general anesthesia has been an indispensable component of modern surgery. While traditionally considered safe and beneficial in many pathological settings, hundreds of preclinical studies in various animal species have raised concerns about the detrimental and long-lasting consequences that general anesthetics may cause to the developing brain. Clinical evidence of anesthetic neurotoxicity in humans continues to mount as we continue to contemplate how to move forward. Notwithstanding the alarming evidence, millions of children are being anesthetized each year, setting the stage for substantial healthcare burdens in the future. Hence, furthering our knowledge of the molecular underpinnings of anesthesia-induced developmental neurotoxicity is crucially important and should enable us to develop protective strategies so that currently available general anesthetics could be safely used during critical stages of brain development. In this mini-review, we provide a summary of select strategies with primary focus on the mechanisms of neuroprotection and potential for clinical applicability. First, we summarize a diverse group of chemicals with the emphasis on intracellular targets and signal-transduction pathways. We then discuss epigenetic and transgenerational effects of general anesthetics and potential remedies, and also anesthesia-sparing or anesthesia-delaying approaches. Finally, we present evidence of a novel class of anesthetics with a distinct mechanism of action and a promising safety profile.

Triiodothyronine attenuates neurocognitive dysfunction induced by sevoflurane in the developing brain of neonatal rats

BACKGROUND

Whilst concerns have been raised about the detrimental effects of general anaesthetics on the brain's development and function in the young, reports have indicated that thyroid hormones are able to promote neurogenesis in the developing brain. This present study aimed to investigate the effects of triiodothyronine (T3) on the neonatal rat brain, following sevoflurane exposure.

METHODS

Postnatal day 7 (P7) ratpups were treated with Triiodothyronine (T3) (1 µg/100 g body weight, i.p. injection, once/day for 3 days) after 2% sevoflurane exposure for 6 h. They were sacrificed at either P7 (immediately), P15 or P30 and their brains were harvested to assess cell death, proliferation in the hippocampus, N-methyl-D-aspartate (NMDA) receptor subunit A and B, and a post-synaptic protein (PSD-95 in the hippocampus,). Neuro-behavioral changes in other cohorts between P27 and P30 were evaluated with Morris water maze and open field tests.

RESULTS

Sevoflurane exposure caused cell death and suppressed the proliferation of astrocytes and neurons, as well as the dendritic growth of neurons in the hippocampus which were all reversed by the administration of T3. Moreover, cognitive function, including learning, memory, and adaptability to a new environment, were impaired by sevoflurane exposure, which was also negated by T3 treatment. Furthermore, sevoflurane decreased the expression of NMDA receptor subunits NR2A and NR2B, as well as PSD-95 in the hippocampus at P15 and those effects of sevoflurane were abolished by T3 administration.

CONCLUSIONS

A potential therapeutic role of T3 in protecting general anesthetic induced neuronal injury in the developing brain is likely to occur through enhancing expression of PSD-95 and the NMDA NR2A and NR2B expression.

Early Development of the GABAergic System and the Associated Risks of Neonatal Anesthesia

Human and animal studies have elucidated the apparent neurodevelopmental effects resulting from neonatal anesthesia. Observations of learning and behavioral deficits in children, who were exposed to anesthesia early in development, have instigated a flurry of studies that have predominantly utilized animal models to further interrogate the mechanisms of neonatal anesthesia-induced neurotoxicity. Specifically, while neonatal anesthesia has demonstrated its propensity to affect multiple cell types in the brain, it has shown to have a particularly detrimental effect on the gamma aminobutyric acid (GABA)ergic system, which contributes to the observed learning and behavioral deficits. The damage to GABAergic neurons, resulting from neonatal anesthesia, seems to involve structure-specific changes in excitatory-inhibitory balance and neurovascular coupling, which manifest following a significant interval after neonatal anesthesia exposure. Thus, to better understand how neonatal anesthesia affects the GABAergic system, we first review the early development of the GABAergic system in various structures that have been the focus of neonatal anesthesia research. This is followed by an explanation that, due to the prolonged developmental curve of the GABAergic system, the entirety of the negative effects of neonatal anesthesia on learning and behavior in children are not immediately evident, but instead take a substantial amount of time (years) to fully develop. In order to address these concerns going forward, we subsequently offer a variety of in vivo methods which can be used to record these delayed effects.

Sevoflurane-Induced miR-211-5p Promotes Neuronal Apoptosis by Inhibiting Efemp2

Sevoflurane exposure can result in serious neurological side effects including neuronal apoptosis and cognitive impairment. Although the microRNA miR-211-5p is profoundly upregulated following sevoflurane exposure in neonatal rodent models, the impact of miR-211-5p on neuronal apoptosis and cognitive impairment postsevoflurane exposure has not yet been elucidated. Here, we found that sevoflurane upregulated miR-211-5p and downregulated EGF-Containing Fibulin Extracellular Matrix Protein 2 (Efemp2, Fibulin-4) levels in vitro and in vivo. Sevoflurane's effect on miR-211-5p expression was based on enhancing primary miR-211 transcription. miR-211-5p targets Efemp2's mRNA 3′-untranslated region, reducing Efemp2 expression. RNA immunoprecipitation revealed significant enrichment of the miR-211-5p:Efemp2 mRNA dyad in the RNA-induced silencing complex. miR-211-5p mimics downregulated Efemp2, leading to phosphorylation of Smad2 and Smad3, upregulation of pro-apoptotic Bim, and mitochondrial release of allograft inflammatory factor 1 and cytochrome C. In contrast, miR-211-5p hairpin inhibitor (AntimiR-211-5p) negatively regulated this apoptotic pathway and reduced neuronal apoptosis in an Efemp2-dependent manner. Sevoflurane-exposed mice administered AntimiR-211-5p displayed reduced cortical apoptosis levels and near-term cognitive impairment. In conclusion, sevoflurane-induced miR-211-5p promotes neuronal apoptosis via Efemp2 inhibition. Summary statement: This study revealed the significance of sevoflurane-induced increases in miR-211-5p on the promotion of neuronal apoptosis via inhibition of Efemp2 and its downstream targets.

The importance of non-coding RNAs in environmental stress-related developmental brain disorders: A systematic review of evidence associated with exposure to alcohol, anesthetic drugs, nicotine, and viral infections

Brain development is a dynamic and lengthy process that includes cell proliferation, migration, neurogenesis, gliogenesis, synaptogenesis, and pruning. Disruption of any of these developmental events can result in long-term outcomes ranging from brain structural changes, to cognitive and behavioral abnormality, with the mechanisms largely unknown. Emerging evidence suggests non-coding RNAs (ncRNAs) as pivotal molecules that participate in normal brain development and neurodevelopmental disorders. NcRNAs such as long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) are transcribed from the genome but not translated into proteins. Many ncRNAs have been implicated as tuners of cell fate. In this review, we started with an introduction of the current knowledge of lncRNAs and miRNAs, and their potential roles in brain development in health and disorders. We then reviewed and discussed the evidence of ncRNA involvement in abnormal brain development resulted from alcohol, anesthetic drugs, nicotine, and viral infections. The complex connections among these ncRNAs were also discussed, along with potential overlapping ncRNA mechanisms, possible pharmacological targets for therapeutic/neuroprotective interventions, and potential biomarkers for brain developmental disorders.

Implementation of the Feed and Swaddle Technique as a Non-Pharmacological Strategy to Conduct Brain Magnetic Resonance Imaging in Very Low Birth Weight Infants

Purpose: Magnetic resonance imaging (MRI) is a useful tool for evaluating brain injury and maturation in preterm infants and often requires sedation to acquire images of sufficient quality. Infant sedation is often associated with adverse events, despite extreme precautions. In this study, the swaddling technique was investigated as an alternative non-pharmacological strategy to obtain brain MRIs of sufficient quality.Methods: We applied the feed and swaddle technique during routine brain MRI as a quality improvement project and compared its morbidity with that of sedation in a historic age-matched group. Seventy-nine very low birth weight infants in the neonatal intensive care unit of Ajou University Hospital (Suwon, Korea) were enrolled. Thirty-two (40.5%) infants were in the feed and swaddling group, and 47 (59.5%) were in the sedation group.Results: The morbidity associated with the cardiopulmonary system (swaddling group vs. sedation group: 53.13% [n=17] vs. 63.83% [n=30], P=0.723) and central nervous system (40.63% [n=13] vs. 29.79% [n=14], P=0.217) were not significantly different between groups. The MRI failure rate was not significantly different (swaddling group vs. sedation group: 12.5% [n=4] vs. 4.3% [n=2], P=0.174). The MRI scanning time was longer in the swaddling group than in the sedation group (76.5±20.3 minutes vs. 61.5±13.6 minutes, P=0.001). Cardiopulmonary adverse events were significantly less common in the swaddling group than in the sedation group (3.13% [n=1] vs. 34.04% [n=16], P=0.002).Conclusion: The success rate of MRI was comparable between the swaddling technique and sedation. Furthermore, despite the drawback of prolonged scan time, cardiopulmonary adverse events are fewer with swaddling than with sedative agents. Therefore, swaddling can be an alternative to sedation or anesthesia when performing neonatal MRI scans.

Perioperative sedation requirements of infants aged 0 to 3 months subjected to lower-body surgery under caudal blockade: a randomized controlled trial

BACKGROUND

It remains unclear how much sedation is required for subumbilical surgery under caudal blockade, and sedatives may carry a poorly understood risk of late sequelae in infants. We designed a randomized controlled study to evaluate total propofol consumption and perioperative sedation quality with the avoidance of continuous perioperative sedation in infants undergoing surgery under caudal anesthesia.

METHODS

Thirty-two infants (age: 0-3 months) were randomized to one of two groups in which perioperative administration of propofol was provided either "as needed" or by continuous infusion (5 mg kg-1 h-1). After induction of anesthesia via a facemask with sevoflurane, a venous access was established and 1 ml kg-1 of ropivacaine 0.35% was injected for caudal anesthesia. Intraoperative stress was assessed by repeated recording Comfort Behavioral Scale scores and heart rates.

RESULTS

Significantly (p = 0.0001) less propofol was administered in the as-needed group (0.7 ± 1.4 mg/kg) than in the continuous-infusion group (3.0 ± 1.6 mg/kg). This difference was not reflected in different requirements of additional intraoperative sedation (0.5 ± 0.8 mg/kg in 5 versus 0.6 ± 1.0 mg/kg in 4 cases; p = 0.76).

CONCLUSIONS

As needed propofol administration offers no disadvantage in terms of intraoperative sedation, but significant dose reductions can be achieved by avoiding continuous propofol infusion.

Exposure to general anaesthesia in childhood and the subsequent risk of attention-deficit hyperactivity disorder: A meta-analysis of cohort studies

BACKGROUND

The evidence for a relationship between general anaesthesia induced in childhood and the risk of attention-deficit hyperactivity disorder (ADHD) in later life is inconsistent. We systematically assessed whether such an association existed.

METHODS

We searched the PubMed and EMBASE databases for relevant cohort studies. Relative risks (RRs) and 95 % confidence intervals (CIs) were calculated to determine the relationship between induction of childhood general anaesthesia and the risk of ADHD in later life.

RESULTS

Seven studies (eight publications) on developmental outcomes after the induction of childhood general anaesthesia met our inclusion criteria but not our exclusion criteria. Repeat childhood general anaesthesia (RR = 1.84, 95 CI% 1.14-2.97; P < 0.001; I² = 74.8 %), but not one-off general anaesthesia (RR = 1.09, 95 CI% 0.93-1.27; P = 0.301; I² = 0%), was associated with an increased risk of ADHD in later life. The association was evident only when the total general anaesthesia exposure exceeded 90 min.

CONCLUSIONS

Our meta-analysis indicated that the effect of general anaesthesia on the risk of ADHD is dose- or duration-dependent.

Emerging Role of Long Noncoding RNAs in Perioperative Neurocognitive Disorders and Anesthetic-Induced Developmental Neurotoxicity

Preclinical investigations in animal models have consistently demonstrated neurobiological changes and life-long cognitive deficits following exposure to widely used anesthetics early in life. However, the mechanisms by which these exposures affect brain function remain poorly understood, therefore, limiting the efficacy of current diagnostic and therapeutic options in human studies. The human brain exhibits an abundant expression of long noncoding RNAs (lncRNAs). These biologically active transcripts play critical roles in a diverse array of functions, including epigenetic regulation. Changes in lncRNA expression have been linked with brain development, normal CNS processes, brain injuries, and the development of neurodegenerative diseases, and many lncRNAs are known to have brain-specific expression. Aberrant lncRNA expression has also been implicated in areas of growing importance in anesthesia-related research, including anesthetic-induced developmental neurotoxicity (AIDN), a condition defined by neurological changes occurring in patients repeatedly exposed to anesthesia, and the related condition of perioperative neurocognitive disorder (PND). In this review, we detail recent advances in PND and AIDN research and summarize the evidence supporting roles for lncRNAs in the brain under both normal and pathologic conditions. We also discuss lncRNAs that have been linked with PND and AIDN, and conclude with a discussion of the clinical potential for lncRNAs to serve as diagnostic and therapeutic targets for the prevention of these neurocognitive disorders and the challenges facing the identification and characterization of associated lncRNAs.

Age-dependent cross frequency coupling features from children to adults during general anesthesia

BACKGROUND

The frequency coupling characteristics in electroencephalogram (EEG) induced by anesthetics have been well studied in adults, but the investigation of the age-dependent cross frequency coupling features from children to adults is still lacking.

METHODS

We analyzed EEG signals recorded from pediatric to adult patients (n = 131), separated into six age groups: <1 year (n = 15), 1-3 years (n = 23), 3-6 years (n = 19), 6-12 years (n = 18), 12-18 years (n = 16), and 18-45 years (n = 40). Age related EEG power and cross frequency coupling analysis (phase amplitude coupling (PAC) and quadratic phase coupling) of data from maintenance of a surgical state of anesthesia (MOSSA) was conducted. Also, for patients of ages less than 6 years, we analyzed the performance of cross frequency coupling derived indices in distinguishing the states of wakefulness, MOSSA, and recovery of consciousness (ROC).

RESULTS

(1) During MOSSA, EEG power substantially increased with age from infancy to 3-6 years then decreased with age in the theta-gamma frequency bands. The infant group (<1 year) had the highest slow oscillation (SO) power among all age groups. (2) The distinct PAC pattern is absent in patients less than 1 year of age both in SO-alpha and delta-alpha frequency band coupling during propofol induced unconsciousness. The modulation index between delta and alpha oscillations in MOSSA increased with age. (3) Wavelet bicoherence derived indices reach their peaks in the 3-6 years group and then decrease with age growth. (4) The Diag_En index (normalized entropy of the diagonal bicoherence entries of the bicoherence matrix) performed the best at distinguishing different states for ages less than 6 years (p<0.05).

CONCLUSIONS

The combination of propofol induction and sevoflurane maintenance exhibited age-dependent EEG power spectra, PAC, and bicoherence, likely related to brain development. These observations suggest new rules for infant and child brain state monitoring during general anesthesia are needed.

Pachypodol protects newborn rats from anaesthesia-induced apoptosis in the developing brain by regulating the JNK/ERK pathway

Anaesthesia exposure causes changes in the developing brain and affects behaviour and memory. This study examined the beneficial effect of pachypodol against isoflurane (ISF)-induced neuronal injury. Seven-day-old rats were treated with 10 mg/kg and 30 mg/kg intravenous pachypodol 30 min before exposure to ISF (0.75%) for 6 h. Oxidative stress and other biochemical parameters were assessed in the brain tissue and serum using enzyme-linked immunosorbent assay. Additionally, a terminal deoxynucleotidyl transferase dUTP nick-end labelling (TUNEL) assay was performed to assess neuronal cell apoptosis in several regions of the hippocampus. Cognitive function and neurological scores were determined in the pachypodol-treated neuron-injured rats. Cytokine levels and oxidative stress were reduced in the pachypodol-treated group compared with the ISF group. In addition, cognitive deterioration was reversed in pachypodol-treated compared with ISF-treated rats. Thus, treatment with pachypodol reduced neuronal apoptosis in neuron-injured rats. Moreover, pachypodol ameliorated changes to the JNK/ERK/Akt pathway in brain-injured rats. In conclusion, pachypodol treatment prevents neuronal apoptosis in ISF-treated rats by regulating the JNK/ERK pathway.

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.

Early-life sevoflurane exposure impairs fear memory by suppressing extracellular signal-regulated kinase signaling in the bed nucleus of stria terminalis GABAergic neurons

Sevoflurane exposure in neonates induces long-term impairment of learning and memory; however, its effect on cognition in the later developmental period and the underlying mechanisms remain unclear. In the present study, we showed that multiple sevoflurane exposures impaired fear memory at long retention delays in neonatal (postnatal day 7) and preadolescent mice (postnatal day 22), but not in mice at older ages. After the fear memory test, expression of phosphorylated extracellular signaling-regulated kinase (p-ERK) and c-fos were elevated in the bed nucleus of the stria terminalis (BNST) and central amygdala, but not in the hippocampus or prefrontal cortex. The upregulation of p-ERK was restricted to populations of γ-aminobutyric acid (GABAergic) neurons and was inhibited by multiple sevoflurane exposures. Intra-BNST injection of ERK inhibitor also impaired fear memory at long retention delays. In contrast, intra-BNST injection of ERK agonist attenuated impaired fear memory caused by repeated sevoflurane exposures. Injection of sevoflurane in the BNST but not the caudate putamen impaired the fear memory at long retention delays in preadolescent mice. Finally, chemogenetic activation of BNST GABAergic neurons by designer receptors exclusively activated by designer drug (DREADD) reversed the impaired fear memory at long retention delays by multiple sevoflurane exposures. These findings suggest that multiple sevoflurane exposures impaired fear memory at long retention delays in preadolescent mice by suppressing the ERK signaling in GABAergic neurons in the BNST.

A synthetic peptide rescues rat cortical neurons from anesthetic-induced cell death, perturbation of growth and synaptic assembly

Anesthetics are deemed necessary for all major surgical procedures. However, they have also been found to exert neurotoxic effects when tested on various experimental models, but the underlying mechanisms remain unknown. Earlier studies have implicated mitochondrial fragmentation as a potential target of anesthetic-induced toxicity, although clinical strategies to protect their structure and function remain sparse. Here, we sought to determine if preserving mitochondrial networks with a non-toxic, short-life synthetic peptide—P110, would protect cortical neurons against both inhalational and intravenous anesthetic-induced neurotoxicity. This study provides the first direct and comparative account of three key anesthetics (desflurane, propofol, and ketamine) when used under identical conditions, and demonstrates their impact on neonatal, rat cortical neuronal viability, neurite outgrowth and synaptic assembly. Furthermore, we discovered that inhibiting Fis1-mediated mitochondrial fission reverses anesthetic-induced aberrations in an agent-specific manner. This study underscores the importance of designing mitigation strategies invoking mitochondria-mediated protection from anesthetic-induced toxicity in both animals and humans.

Preventing Neurodegeneration by Controlling Oxidative Stress: The Role of OXR1

Parkinson’s disease, diabetic retinopathy, hyperoxia induced retinopathy, and neuronal damage resulting from ischemia are among the notable neurodegenerative diseases in which oxidative stress occurs shortly before the onset of neurodegeneration. A shared feature of these diseases is the depletion of OXR1 (oxidation resistance 1) gene products shortly before the onset of neurodegeneration. In animal models of these diseases, restoration of OXR1 has been shown to reduce or eliminate the deleterious effects of oxidative stress induced cell death, delay the onset of symptoms, and reduce overall severity. Moreover, increasing OXR1 expression in cells further increases oxidative stress resistance and delays onset of disease while showing no detectable side effects. Thus, restoring or increasing OXR1 function shows promise as a therapeutic for multiple neurodegenerative diseases. This review examines the role of OXR1 in oxidative stress resistance and its impact on neurodegenerative diseases. We describe the potential of OXR1 as a therapeutic in light of our current understanding of its function at the cellular and molecular level and propose a possible cascade of molecular events linked to OXR1’s regulatory functions.

First-attempt success rate of video laryngoscopy in small infants (VISI): a multicentre, randomised controlled trial

BACKGROUND

Orotracheal intubation of infants using direct laryngoscopy can be challenging. We aimed to investigate whether video laryngoscopy with a standard blade done by anaesthesia clinicians improves the first-attempt success rate of orotracheal intubation and reduces the risk of complications when compared with direct laryngoscopy. We hypothesised that the first-attempt success rate would be higher with video laryngoscopy than with direct laryngoscopy.

METHODS

In this multicentre, parallel group, randomised controlled trial, we recruited infants without difficult airways abnormalities requiring orotracheal intubation in operating theatres at four quaternary children's hospitals in the USA and one in Australia. We randomly assigned patients (1:1) to video laryngoscopy or direct laryngoscopy using random permuted blocks of size 2, 4, and 6, and stratified by site and clinician role. Guardians were masked to group assignment. The primary outcome was the proportion of infants with a successful first attempt at orotracheal intubation. Analysis (modified intention-to-treat [mITT] and per-protocol) used a generalised estimating equation model to account for clustering of patients treated by the same clinician and institution, and adjusted for gestational age, American Society of Anesthesiologists physical status, weight, clinician role, and institution. The trial is registered at ClinicalTrials.gov, NCT03396432.

FINDINGS

Between June 4, 2018, and Aug 19, 2019, 564 infants were randomly assigned: 282 (50%) to video laryngoscopy and 282 (50%) to direct laryngoscopy. The mean age of infants was 5·5 months (SD 3·3). 274 infants in the video laryngoscopy group and 278 infants in the direct laryngoscopy group were included in the mITT analysis. In the video laryngoscopy group, 254 (93%) infants were successfully intubated on the first attempt compared with 244 (88%) in the direct laryngoscopy group (adjusted absolute risk difference 5·5% [95% CI 0·7 to 10·3]; p=0·024). Severe complications occurred in four (2%) infants in the video laryngoscopy group compared with 15 (5%) in the direct laryngoscopy group (-3·7% [-6·5 to -0·9]; p=0·0087). Fewer oesophageal intubations occurred in the video laryngoscopy group (n=1 [<1%]) compared with in the direct laryngoscopy group (n=7 [3%]; -2·3 [-4·3 to -0·3]; p=0·028).

INTERPRETATION

Among anaesthetised infants, using video laryngoscopy with a standard blade improves the first-attempt success rate and reduces complications.

FUNDING

Anaesthesia Patient Safety Foundation, Society for Airway Management, and Karl Storz Endoscopy.

Incisional hernia after surgical correction of abdominal congenital anomalies in infants: a systematic review with meta-analysis

Incisional hernia (IH) in children could result in life-threatening complications, including incarceration and bowel strangulation. The incidence and risk factors of IH in infants are scarcely reported. Since IH-correction may require extensive surgery and a long recovery program, identifying infants and birth defects at risk, may lead to a different approach during the primary surgery. Therefore, the aim of this review is to systematically review the available data on the incidence of IH following surgery for congenital anomalies in infants. All studies describing IH were considered eligible. PubMed and Embase were searched and risk of bias was assessed. Primary outcome was the incidence of IH, secondary outcomes were difference in IH occurrence between disease severity (complex vs simple) and closure method (SILO vs primary closure) in gastroschisis patients. A meta-analysis was performed to pool the reported incidences in total and per congenital anomaly separately. Subgroup analysis within gastroschisis articles was performed. The 50 included studies represent 3140 patients. The pooled proportion of IH was 0.03 (95% CI 0.02–0.05; I² = 79%, p ≤ 0.01) all anomalies combined. Gastroschisis (GS) reported highest pooled proportion 0.10 (95% CI 0.06–0.17; n = 142/1273; I² = 86%; p ≤ 0.01). SILO closure (OR 3.09) and simple gastroschisis, i.e. without additional anomalies, (OR 0.18) were of significant influence. This review reports the incidence of IH in infants with different congenital abdominal anomalies, of which gastroschisis reported the highest risk. In GS patients, complex GS and SILO closure are risk factors for IH development.

Pediatric Anesthesia Specialty Societies and Multi-Institutional Collaborations

Pediatric anesthesiology is a subspecialty of anesthesiology that deals with the high-risk pediatric population. The specialty has made significant advancement in large collaborative efforts to study and increase patient safety, including the creation of international societies, a dedicated journal, special committees and interest groups, and multi-institution databases for research and quality improvement. Readily available resources were created to help with the education of future pediatric anesthesiologists as well as continuing medical education. Conclusions: Specialty societies and collaborations in pediatric anesthesia are crucial for continuous improvement in the care of children. They promote research, education, quality improvement, and advocacy at the local, national, and international level.