Early childhood general anaesthesia exposure and neurocognitive development

AMPK‑SIRT1 pathway dysfunction contributes to neuron apoptosis and cognitive impairment induced by sevoflurane

The anesthetic sevoflurane (Sev) is widely used because of its low blood-gas partition coefficient and lack of pungency. However, the application of Sevmay lead to cognitive impairment later in life. Previous results have indicated that exposure to Sev-induced neuronal apoptosis and cognitive dysfunction in a rat model, but much work remains to elucidate the mechanism. In the present study, inhibition in the AMP-activated protein kinase/Sirtuin 1 (AMPK/SIRT1) signaling pathway and a decrease in AMPK/SIRT1 activity was found to occur concomitantly in neuronal apoptosis induced by Sev. AICAR, an activator of AMPK, was able to suppress Sev-induced neuronal apoptosis and SIRT1 activity reduction in vitro. Further animal studies also showed that AICAR treatment blocked the deleterious cognition and AMPK/SIRT1 activity reduction in the cognition impairment rats induced by Sev. Taken together, it was concluded that the AMPK/SIRT1 signaling pathway mediates neuronal apoptosis and cognition impairment induced by Sev. The study provides evidence that AMPK activation ameliorates Sev-induced cognitive deficits.

Infant isoflurane exposure affects social behaviours, but does not impair specific cognitive domains in juvenile non-human primates

BACKGROUND

Clinical studies show that children exposed to anaesthetics for short times at young age perform normally on intelligence tests, but display altered social behaviours. In non-human primates (NHPs), infant anaesthesia exposure for several hours causes neurobehavioural impairments, including delayed motor reflex development and increased anxiety-related behaviours assessed by provoked response testing. However, the effects of anaesthesia on spontaneous social behaviours in juvenile NHPs have not been investigated. We hypothesised that multiple, but not single, 5 h isoflurane exposures in infant NHPs are associated with impairments in specific cognitive domains and altered social behaviours at juvenile age.

METHODS

Eight Rhesus macaques per group were anaesthetised for 5 h using isoflurane one (1×) or three (3×) times between postnatal days 6 and 12 or were exposed to room air (control). Cognitive testing, behavioural assessments in the home environment, and provoked response testing were performed during the first 2 yr of life.

RESULTS

The cognitive functions tested did not differ amongst groups. However, compared to controls, NHPs in the 3× group showed less close social behaviour (P=0.016), and NHPs in the 1× group displayed increased anxiety-related behaviours (P=0.038) and were more inhibited towards novel objects (P<0.001).

CONCLUSIONS

5 h exposures of NHPs to isoflurane during infancy are associated with decreased close social behaviour after multiple exposures and more anxiety-related behaviours and increased behavioural inhibition after single exposure, but they do not affect the cognitive domains tested. Our findings are consistent with behavioural alterations in social settings reported in clinical studies, which may guide future research.

Propofol Attenuates Isoflurane-Induced Neurotoxicity and Cognitive Impairment in Fetal and Offspring Mice

BACKGROUND

Anesthesia in pregnant rodents causes neurotoxicity in fetal and offspring rodents. However, the underlying mechanisms and targeted treatments remain largely to be determined. Isoflurane and propofol are among commonly used anesthetics. Thus, we set out to investigate whether propofol can mitigate the isoflurane-induced neurotoxicity in mice.

METHODS

Pregnant C57BL/6 mice at gestational day 15 (G15) were randomly assigned to 4 groups: control, isoflurane, propofol, and isoflurane plus propofol. Levels of interleukin (IL)-6 and poly-ADP ribose polymerase (PARP) fragment were measured in the brains of G15 embryos, and levels of postsynaptic density (PSD)-95 and synaptophysin were determined in the hippocampal tissues of postnatal day 31 (P31) offspring using Western blotting and immunohistochemical staining. Learning and memory functions in P31 offspring were determined using a Morris water maze test.

RESULTS

Isoflurane anesthesia in pregnant mice at G15 significantly increased brain IL-6 (222.6% ± 36.45% vs 100.5% ± 3.43%, P < .0001) and PARP fragment (384.2% ± 50.87% vs 99.59% ± 3.25%, P < .0001) levels in fetal mice and reduced brain PSD-95 (30.76% ± 2.03% vs 100.8% ± 2.25%, P < .0001) and synaptophysin levels in cornu ammonis (CA) 1 region (57.08% ± 4.90% vs 100.6% ± 2.20%, P < .0001) and dentate gyrus (DG; 56.47% ± 3.76% vs 99.76% ± 1.09%, P < .0001) in P31 offspring. Isoflurane anesthesia also impaired cognitive function in offspring at P31. Propofol significantly mitigated isoflurane-induced increases in brain IL-6 (117.5% ± 10.37% vs 222.6% ± 36.45%, P < .0001) and PARP fragment (205.1% ± 35.99% vs 384.2% ± 50.87%, P < .0001) levels in fetal mice, as well as reductions in PSD-95 (49.79% ± 3.43% vs 30.76% ± 2.03%, P < .0001) and synaptophysin levels in CA1 region (85.57% ± 2.97% vs 57.08% ± 4.90%, P < .0001) and DG (85.05% ± 1.87% vs 56.47% ± 3.76%, P < .0001) in hippocampus of P31 offspring. Finally, propofol attenuated isoflurane-induced cognitive impairment in offspring.

CONCLUSIONS

These findings suggest that gestational isoflurane exposure in mice induces neuroinflammation and apoptosis in embryos and causes cognitive impairment in offspring. Propofol can attenuate these isoflurane-induced detrimental effects.

TrkC Overexpression Protects Sevoflurane-Induced Neurotoxicity in Human Induced Pluripotent Stem Cell-Derived Neurons

BACKGROUND

Inhaled anesthetic sevoflurane (SEVO) may induce cortical neurotoxicity and memory dysfunction in both animals and humans. In this study, we investigated the toxic effects of SEVO on human induced pluripotent stem cell (iPS)-derived neurons.

METHODS

Human iPS-derived neurons were exposed to SEVO in vitro. SEVO-induced toxic effects were examined with the viability, live caspase 3/7, and neurite density assays, respectively. The effects of SEVO on the receptors of the tyrosine kinases TrkA, TrkB, and TrkC were assessed by qRT-PCR. TrkA, TrkB, and TrkC were ectopically overexpressed in human iPS-derived neurons. Their functional effects on SEVO-induced human iPS-derived neuron toxicity were further investigated.

RESULTS

SEVO induced dose-dependent cell death, caspase 3/7 elevation, neurite degeneration, and the downregulation of Trk receptors in human iPS-derived neurons. Adenovirus-mediated Trk receptor overexpression selectively upregulated endogenous TrkA, TrkB, or TrkC gene expressions in human iPS-derived neurons. Specifically, TrkC overexpression, but not TrkA or TrkB overexpression was found to overcome the neurotoxic effects of SEVO in human iPS-derived neurons.

CONCLUSIONS

SEVO may induce neurotoxicity in human iPS-derived neurons, and its neurotoxic damage could be protected by the overexpression of TrkC.

Behavior and Regional Cortical BOLD Signal Fluctuations Are Altered in Adult Rabbits After Neonatal Volatile Anesthetic Exposure

Neonatal and infant exposure to volatile anesthetics has been associated with long-term learning, memory, and behavioral deficits. Although early anesthesia exposure has been linked to a number of underlying structural abnormalities, functional changes associated with these impairments remain poorly understood. To investigate the relationship between functional alteration in neuronal circuits and learning deficiency, resting state functional MRI (rsfMRI) connectivity was examined in adolescent rabbits exposed to general anesthesia as neonates (1 MAC isoflurane for 2 h on postnatal days P8, P11, and P14) and unanesthetized controls before and after training with a trace eyeblink classical conditioning (ECC) paradigm. Long-range connectivity was measured between several key regions of interest (ROIs), including primary and secondary somatosensory cortices, thalamus, hippocampus, and cingulate. In addition, metrics of regional BOLD fluctuation amplitudes and coherence, amplitude of low-frequency fluctuation (ALFF), fractional ALFF (fALFF), and regional homogeneity (ReHo) were calculated. Our results showed that the trace ECC learning rate was significantly lower in the anesthesia-exposed group. No anesthesia-related changes in long-range connectivity, fALFF, or ReHo were found between any ROIs. However, ALFF was significantly higher in anesthesia-exposed rabbits in the primary and secondary somatosensory cortices, and ALFF in those areas was a significant predictor of the learning performance for trace ECC. The absence of anesthesia-related changes in long-range thalamocortical connectivity indicates that functional thalamocortical input is not affected. Higher ALFF in the somatosensory cortex may indicate the developmental disruption of cortical neuronal circuits after neonatal anesthesia exposure, including excessive neuronal synchronization that may underlie the observed cognitive deficits.

Safety of anesthetic exposure on the developing brain - Do we have the answer yet?

During the past two decades, a vast number of studies done on rodents and nonhuman primates have implicated general anesthetic exposure of developing brains in producing neurotoxicity leading to various structural and functional neurological abnormalities with cognitive and behavioral deficits later in life. However, it is still unclear whether these findings translate to children and whether single exposure to anesthesia in childhood can have long-term neuro-developmental risks. Considering the fact that a large number of healthy young children are undergoing elective surgery under general anesthesia globally, any such potential neurocognitive risk of pediatric anesthesia is a serious public health issue and is therefore important to understand. This review aims to assess the current preclinical and clinical evidence related to anesthetic neurotoxicity.

Tau Contributes to Sevoflurane-induced Neurocognitive Impairment in Neonatal Mice

BACKGROUND

Sevoflurane anesthesia induces Tau phosphorylation and cognitive impairment in neonatal but not in adult mice. This study tested the hypothesis that differences in brain Tau amounts and in the activity of mitochondria-adenosine triphosphate (ATP)-Nuak1-Tau cascade between the neonatal and adult mice contribute to the age-dependent effects of sevoflurane on cognitive function.

METHODS

6- and 60-day-old mice of both sexes received anesthesia with 3% sevoflurane for 2 h daily for 3 days. Biochemical methods were used to measure amounts of Tau, phosphorylated Tau, Nuak1, ATP concentrations, and mitochondrial metabolism in the cerebral cortex and hippocampus. The Morris water maze test was used to evaluate cognitive function in the neonatal and adult mice.

RESULTS

Under baseline conditions and compared with 60-day-old mice, 6-day-old mice had higher amounts of Tau (2.6 ± 0.4 [arbitrary units, mean ± SD] vs. 1.3 ± 0.2; P < 0.001), Tau oligomer (0.3 ± 0.1 vs. 0.1 ± 0.1; P = 0.008), and Nuak1 (0.9 ± 0.3 vs. 0.3 ± 0.1; P = 0.025) but lesser amounts of ATP (0.8 ± 0.1 vs. 1.5 ± 0.1; P < 0.001) and mitochondrial metabolism (74.8 ± 14.1 [pmol/min] vs. 169.6 ± 15.3; P < 0.001) in the cerebral cortex. Compared with baseline conditions, sevoflurane anesthesia induced Tau phosphorylation at its serine 202/threonine 205 residues (1.1 ± 0.4 vs. 0.2 ± 0.1; P < 0.001) in the 6-day-old mice but not in the 60-day-old mice (0.05 ± 0.04 vs. 0.03 ± 0.01; P = 0.186). The sevoflurane-induced Tau phosphorylation and cognitive impairment in the neonatal mice were both attenuated by the inhibition of Nuak1 and the treatment of vitamin K2.

CONCLUSIONS

Higher brain Tau concentrations and lower brain mitochondrial metabolism in neonatal compared with adult mice contribute to developmental stage-dependent cognitive dysfunction after sevoflurane anesthesia.

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.

Current Practices in Pediatric Dermatology Laser Therapy: An International Survey

BACKGROUND AND OBJECTIVES

To date, there are no well-established guidelines regarding laser therapy for the treatment of cutaneous lesions in pediatric patients. We aim to ascertain the types of lasers commonly used, types of lesions treated, and factors that affect the selection of specific laser modalities in pediatric patients.

STUDY DESIGN/MATERIALS AND METHODS

An anonymous online survey was distributed to healthcare providers who treat children with lasers through listservs of four major national and international dermatology and laser organizations.

RESULTS

Outpatient office-based procedure rooms are the most common clinical setting for laser procedures (74.4%), and pulsed dye laser is the most commonly used laser (95.4%). Conditions routinely treated with lasers included port wine stains (95.4%), infantile hemangiomas (81.5%), other vascular lesions (81.5%), scars (77.7%), and hair (60.8%). 84.4% of respondents expressed concern about general anesthesia in patients <2 years old. Nevi of Ota is treated with laser more frequently (52.3%) than other pigmented lesions.

LIMITATIONS

Limited generalizability of case examples to general conditions.

CONCLUSIONS

Vascular lesions are the most common lesions treated with lasers in pediatric dermatology patients, and most providers are using these devices in the outpatient setting. Many providers are concerned about the effects of repeated general anesthesia in infants, and there appears to be a trend toward providing laser therapy in the outpatient setting without general anesthesia. Lasers Surg. Med. © 2020 Wiley Periodicals LLC.

Early Mobilization of Infants Intubated for Acute Respiratory Failure

BACKGROUND

Early mobility in the intensive care unit is being promoted as a way to improve outcomes but has not been studied in young infants.

OBJECTIVE

To determine the safety of a holding intervention for infants intubated for respiratory failure.

METHODS

Infants less than 6 months of age intubated for respiratory failure underwent a holding intervention in which a caretaker held the infant at least twice a day once the infant was medically stabilized. Rates of adverse events were compared with historical controls matched by age and Pediatric Index of Mortality 2 score. Vital signs before and during holding were recorded to assess for physiologic tolerance.

RESULTS

Twenty-four infants with a total of 158 holding interventions were studied. Mean holding duration was 99 minutes. Twenty holding interventions were terminated early, most commonly because of agitation. The 24 historical controls had 1 unplanned extubation and 2 arterial catheter removals. The intervention group had no unplanned extubations, inadvertent central catheter removals, or urinary catheter removals and had 1 arterial catheter removal that was not associated with holding. Vital signs before and during holding were similar. There were no differences between the control and intervention groups in duration of intubation (7.3 vs 6.0 days, P = .98), length of intensive care unit stay (9.1 vs 9.0 days, P = .52), or length of hospital stay (11.5 vs 12.5 days, P = .28).

CONCLUSIONS

Holding intubated infants in the intensive care unit was well tolerated, without an increase in adverse events.

Provision and Utilization of Team- and Community-Based Operative Care for Patients With Cleft Lip/Palate in North Carolina

OBJECTIVE

To characterize operative care for cleft lip and/or palate (CL/P) based on location (ie, from American Cleft Palate Craniofacial Association [ACPA]-approved multidisciplinary teams or from community providers).

DESIGN

Cross-sectional analysis of Healthcare Cost and Utilization Project State Inpatient Database and State Ambulatory Surgery & Services Database databases for North Carolina from 2012 to 2015.

SETTING/PATIENTS AND MAIN OUTCOME MEASURES

Clinical encounters for children with CL/P undergoing operative procedures were identified, classified by location as "Team" versus "Community," and characterized by demographic, geographic, clinical, and procedural factors. A secondary evaluation reviewed concordance of team and community practices with an ACPA guideline related to coordination of care.

RESULTS

Three teams and 39 community providers performed a total of 3010 cleft-related procedures across 2070 encounters. Teams performed 69.7% of total volume and performed the majority of cleft procedures, including cleft lip repair, palate repair, alveolar bone grafting, and correction of velopharyngeal insufficiency. Community locations principally offered myringotomy and rhinoplasty. Team care was associated with higher guideline concordance.

CONCLUSIONS

American Cleft Palate Craniofacial Association -approved team-based care accounts for the majority of cleft-related care in North Carolina; however, a substantial volume of cleft-related procedures was provided by community providers, with 3 providers accounting for the vast majority of community cases.

The Feasibility of Magnetic Resonance Imaging Without General Anesthesia Using the "Bundle and Scan" Technique for Infants With Sensorineural Hearing Loss

OBJECTIVE

The purpose of this study is to determine the feasibility of magnetic resonance imaging (MRI) without general anesthesia (GA) for infants being evaluated for sensorineural hearing loss (SNHL) using the bundle and scan technique.

STUDY DESIGN

Retrospective study.

SETTING

Pediatric tertiary care hospital.

PATIENTS

All infants who underwent MRI using the bundle and scan technique as part of the diagnostic workup for unilateral or bilateral SNHL between June 2016 to April 2019 were included.

MAIN OUTCOME MEASURE

The primary outcome was the proportion of clinically useful images produced.

RESULTS

We reviewed 21 bundle and scan MRI examinations in infants being evaluated for SNHL. Patients had a median age of 10 (range: 6-25) weeks at the time of MRI. Motion artifact was noted in 38% (8/21) of cases. Eighty-six percent (18/21) of the magnetic resonance images produced using the bundle and scan technique were of diagnostic quality and/or sufficient for surgical planning for cochlear implantation. Repeat imaging with GA was required for three cases (14%) as the initial images were not clinically useful. All patients requiring GA had unilateral SNHL. All patients with bilateral SNHL successfully underwent MRI without GA using the bundle and scan technique.

CONCLUSION

The results of our study demonstrate that it is feasible to perform MRI using the bundle and scan technique in the majority of young infants being evaluated for SNHL. This has the potential to help determine cochlear implant candidacy earlier, reduce exposure to GA, and reduce healthcare costs.

Effects of neonatal isoflurane anesthesia exposure on learning-specific and sensory systems in adults

Millions of children undergo general anesthesia each year, and animal and human studies have indicated that exposure to anesthesia at an early age can impact neuronal development, leading to behavioral and learning impairments that manifest later in childhood and adolescence. Here, we examined the effects of isoflurane, a commonly-used general anesthetic, which was delivered to newborn rabbits. Trace eyeblink classical conditioning was used to assess the impact of neonatal anesthesia exposure on behavioral learning in adolescent subjects, and a variety of MRI techniques including fMRI, MR volumetry, spectroscopy and DTI captured functional, metabolic, and structural changes in key regions of the learning and sensory systems associated with anesthesia-induced learning impairment. Our results demonstrated a wide array of changes that were specific to anesthesia-exposed subjects, which supports previous studies that have pointed to a link between early anesthesia exposure and the development of learning and behavioral deficiencies. These findings point to the need for caution in avoiding excessive use of general anesthesia in young children and neonates.

Anesthesia Exposure during Therapy Predicts Neurocognitive Outcomes in Survivors of Childhood Medulloblastoma

OBJECTIVE

To examine the contribution of anesthesia exposure during treatment for childhood medulloblastoma to neurocognitive outcomes 3 years after tumor diagnosis.

STUDY DESIGN

In this retrospective study, anesthesia data were abstracted from medical records for 111 patients treated with risk-adapted protocol therapy at St Jude Children's Research Hospital. Neurocognitive testing data were obtained for 90.9% of patients.

RESULTS

For the 101 patients (62.4% male) who completed testing, mean age at diagnosis was 10.1 years, and 74.3% were staged to have average-risk disease. Anesthesia exposure during treatment ranged from 1 to 52 events (mean = 19.9); mean cumulative duration per patient was 21.1 hours (range 0.7-59.7). Compared with normative expectations (16%), the group had a significantly greater frequency of at-risk scores (<1 SD) on measures of intelligence (28.7%), attention (35.2%), working memory (26.6%), processing speed (46.7%), and reading (25.8%). Including anesthesia exposure duration to linear regression models accounting for age at diagnosis, treatment intensity, and baseline IQ significantly increased the predicted variance for intelligence (r² = 0.59), attention (r² = 0.29), working memory (r² = 0.31), processing speed (r² = 0.44), and reading (r² = 0.25; all P values <.001).

CONCLUSIONS

In survivors of childhood medulloblastoma, a neurodevelopmentally vulnerable population, greater exposure to anesthesia significantly and independently predicts deficits in neurocognitive and academic functioning. When feasible, anesthesia exposure during treatment should be reduced.

Risk of General Anesthesia in Pediatric Skin Procedures with Projection on Tumescent Anesthesia

Background

Uses of general anaesthesia in outpatient invasive procedures have increased, especially in dermatology. Being uncooperative, children often require general anaesthesia, since surgical skin operations are mostly painful.

Aim

The purpose of this study is to evaluate the safety, significant adverse events, and the complication rates related to general anaesthesia, when used among pediatric population undergoing skin procedures.

Methods

We conducted a first retrospective cohort study of patient chart review during the period from September 1, 2017 through September 2019. All patients admitted for pediatric skin procedures during this period have participated in our study. We reviewed selected charts to document any unexpected admissions, adverse events, or complications. Surgical outcomes and anaesthesia complications were reviewed by three anesthesiologists. We assessed inter-rater reliability.

Results

A total of 211 procedures were reported for 211 patients with 19 diagnoses. No adverse events related to anaesthesia were recognized, apart from minor complications noticed in twelve patients. The kappa value range is between 0.78 and 1.00 (95% C.I., 0.46809 to 1.00).

Conclusion

Dermatologist and pediatricians can safely do necessary procedures under general anaesthesia with the supervision of pediatric-trained anesthesiologists while considering other safety and risk precautions and the pediatric age group.

Safety of anesthetic exposure on the developing brain - Do we have the answer yet?

During the past two decades, a vast number of studies done on rodents and nonhuman primates have implicated general anesthetic exposure of developing brains in producing neurotoxicity leading to various structural and functional neurological abnormalities with cognitive and behavioral deficits later in life. However, it is still unclear whether these findings translate to children and whether single exposure to anesthesia in childhood can have long-term neuro-developmental risks. Considering the fact that a large number of healthy young children are undergoing elective surgery under general anesthesia globally, any such potential neurocognitive risk of pediatric anesthesia is a serious public health issue and is therefore important to understand. This review aims to assess the current preclinical and clinical evidence related to anesthetic neurotoxicity.

L-Theanine Attenuates Isoflurane-Induced Injury in Neural Stem Cells and Cognitive Impairment in Neonatal Mice

The neurodevelopmental toxicity of isoflurane has been proved by many studies, which makes it essential to explore the underline mechanisms and search for protective agents to attenuate its neurotoxcity. Accumulating evidence showed that L-theanine had neuroprotective effects on injured neurons and the developing brain. The present study was designed to investigate whether L-theanine could attenuate isoflurane-induced damage in neural stem cells and cognitive impairment in young mice, and to discuss the role of protein kinase B (Akt)-glycogen synthase kinase 3β (GSK-3β) signaling pathway in this process. Multipotential neural stem cells (NSCs) and C57BL/6J mice were treated with either gas mixture, isoflurane, or L-theanine 30 min prior to isoflurane exposure, respectively. NSC viability was detected by CCK-8 assay. NSC proliferation and apoptosis were assessed by immunofluorescence and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling (TUNEL) assay, respectively. The levels of cleaved caspase-3 and phosphorylated (p)-Akt and p-GSK-3β in NSCs were tested by Western blotting. Cognitive function of mice was tested by Morris Water Maze at postnatal day (P) 30-35. The results indicated that isoflurane exposure inhibited NSC viability and proliferation, promoted NSC apoptosis as well as increased caspase-3 activation and down-regulated the expressions of p-Akt and p-GSK-3β in NSCs, and that isoflurane exposure on neonatal mice would induce late cognitive impairment. Pretreatment with L-theanine could attenuate isoflurane-caused damage in NSCs and cognitive deficits in young mice. Addinonally, the protective effects of L-theanine on isoflurane-injured NSCs could be reversed by Akt inhibitor Triciribine. Our data showed that pretreatment with L-theanine eliminated the NSC damage and cognitive impairment induced by isoflurane exposure, and that the neuroprotective effect of L-theanine was associated with the Akt-GSK-3β signaling pathway.

Neuroendocrine, epigenetic, and intergenerational effects of general anesthetics

The progress of modern medicine would be impossible without the use of general anesthetics (GAs). Despite advancements in refining anesthesia approaches, the effects of GAs are not fully reversible upon GA withdrawal. Neurocognitive deficiencies attributed to GA exposure may persist in neonates or endure for weeks to years in the elderly. Human studies on the mechanisms of the long-term adverse effects of GAs are needed to improve the safety of general anesthesia but they are hampered not only by ethical limitations specific to human research, but also by a lack of specific biological markers that can be used in human studies to safely and objectively study such effects. The latter can primarily be attributed to an insufficient understanding of the full range of the biological effects induced by GAs and the molecular mechanisms mediating such effects even in rodents, which are far more extensively studied than any other species. Our most recent experimental findings in rodents suggest that GAs may adversely affect many more people than is currently anticipated. Specifically, we have shown that anesthesia with the commonly used GA sevoflurane induces in exposed animals not only neuroendocrine abnormalities (somatic effects), but also epigenetic reprogramming of germ cells (germ cell effects). The latter may pass the neurobehavioral effects of parental sevoflurane exposure to the offspring, who may be affected even at levels of anesthesia that are not harmful to the exposed parents. The large number of patients who require general anesthesia, the even larger number of their future unexposed offspring whose health may be affected, and a growing number of neurodevelopmental disorders of unknown etiology underscore the translational importance of investigating the intergenerational effects of GAs. In this mini review, we discuss emerging experimental findings on neuroendocrine, epigenetic, and intergenerational effects of GAs.

Coenzyme Q10 alleviates sevoflurane‑induced neuroinflammation by regulating the levels of apolipoprotein E and phosphorylated tau protein in mouse hippocampal neurons

Sevoflurane may exert neurotoxic effects on the developing brain. Coenzyme Q10 (CoQ10) has been reported to reduce sevoflurane anesthesia-induced cognitive deficiency in 6-day-old mice. However, its specific mechanisms remain unknown. Apolipoprotein E (ApoE) has been reported to lead to the initiation of neurodegeneration in patients with Alzheimer's disease (AD) and may serve an important role in anesthesia-induced neurotoxicity. The present study aimed to reveal the role of ApoE in the pathogenesis of tau protein hyperphosphorylation and neuroinflammation enhancement caused by sevoflurane anesthesia, as well as the protective mechanism of CoQ10 in an anesthetic sevoflurane treatment model of primary mouse hippocampal neurons. For that purpose, the neurons were randomly assigned to the following groups: i) Control; ii) sevoflurane; iii) control+corn oil; iv) sevoflurane+corn oil; v) control+CoQ10; and vi) control+CoQ10. CoQ10 or corn oil alone was added to the medium on day 4 of neuron culture. The neurons in the sevoflurane group were treated with 21% O₂, 5% CO₂ and 4.1% sevoflurane for 4 h, whereas the control group only with 21% O₂ and 5% CO₂ on day 5. Samples were collected immediately after anesthesia or control treatment. ATP, superoxidase dismutase (SOD)1, ApoE mRNA, total ApoE, full-length ApoE, ApoE fragments, Tau5, Tau-PS202/PT205 (AT8), Tau-PSer396/404 (PHF1), tumor necrosis factor (TNF)-α, interleukin (IL)-6 and IL-1β levels were measured with ELISA, quantitative PCR, western blotting and immunocytochemistry. The results of the present study indicated that sevoflurane anesthesia significantly decreased the ATP and SOD levels, but increased ApoE mRNA, total ApoE protein, full-length ApoE, ApoE fragments, phosphorylated tau (AT8 and PHF1) and neuroinflammatory factor (TNF-α, IL-6 and IL-1β) expression levels compared with those in the control group. The use of CoQ10 reversed the expression of these factors. These results suggested that sevoflurane treatment damaged mouse hippocampal neurons, which may be associated with the expression of ApoE and its toxic fragments. CoQ10 improved energy replenishment and inhibited oxidative stress, which may lead to a decrease in ApoE and phosphorylated tau protein expression, thus mitigating the sevoflurane-induced neuroinflammation in mouse hippocampal neurons.

Multiple Anesthesia/Surgery Cannot Impair Reference Memory in Adult Mice

Postoperative cognitive dysfunction increases mortality and morbidity in perioperative patients. Numerous studies have demonstrated that multiple surgery/anesthesia during the neurodevelopmental period affects cognitive function, whereas a single anesthesia/surgery rarely causes cognitive dysfunction in adults. However, whether adults who undergo multiple anesthesia/surgery over a short period will experience cognitive dysfunction remains unclear. In this study, central nervous system inflammation and changes in cholinergic markers were investigated in adult mice subjected to multiple laparotomy procedures over a short period of time. The results showed that despite the increased expression of IL-6 and TNF-α in the hippocampus after multiple operations and the activation of microglia, multiple anesthesia/surgery did not cause a decline in cognitive function in adult mice. There were no changes in the cholinergic markers after multiple anesthesia/surgery.

δ-Oscillation Correlates of Anesthesia-induced Unconsciousness in Large-scale Brain Networks of Human Infants

BACKGROUND

Functional brain connectivity studies can provide important information about changes in brain-state dynamics during general anesthesia. In adults, γ-aminobutyric acid-mediated agents disrupt integration of information from local to the whole-brain scale. Beginning around 3 to 4 months postnatal age, γ-aminobutyric acid-mediated anesthetics such as sevoflurane generate α-electroencephalography oscillations. In previous studies of sevoflurane-anesthetized infants 0 to 3.9 months of age, α-oscillations were absent, and power spectra did not distinguish between anesthetized and emergence from anesthesia conditions. Few studies detailing functional connectivity during general anesthesia in infants exist. This study's aim was to identify changes in functional connectivity of the infant brain during anesthesia.

METHODS

A retrospective cohort study was performed using multichannel electroencephalograph recordings of 20 infants aged 0 to 3.9 months old who underwent sevoflurane anesthesia for elective surgery. Whole-brain functional connectivity was evaluated during maintenance of a surgical state of anesthesia and during emergence from anesthesia. Functional connectivity was represented as networks, and network efficiency indices (including complexity and modularity) were computed at the sensor and source levels.

RESULTS

Sevoflurane decreased functional connectivity at the δ-frequency (1 to 4 Hz) in infants 0 to 3.9 months old when comparing anesthesia with emergence. At the sensor level, complexity decreased during anesthesia, showing less whole-brain integration with prominent alterations in the connectivity of frontal and parietal sensors (median difference, 0.0293; 95% CI, -0.0016 to 0.0397). At the source level, similar results were observed (median difference, 0.0201; 95% CI, -0.0025 to 0.0482) with prominent alterations in the connectivity between default-mode and frontoparietal regions. Anesthesia resulted in fragmented modules as modularity increased at the sensor (median difference, 0.0562; 95% CI, 0.0048 to 0.1298) and source (median difference, 0.0548; 95% CI, -0.0040 to 0.1074) levels.

CONCLUSIONS

Sevoflurane is associated with decreased capacity for efficient information transfer in the infant brain. Such findings strengthen the hypothesis that conscious processing relies on an efficient system of integrated information transfer across the whole brain.

Impact of anesthesia exposure in early development on learning and sensory functions

Each year, millions of children undergo anesthesia, and both human and animal studies have indicated that exposure to anesthesia at an early age can lead to neuronal damage and learning deficiency. However, disorders of sensory functions were not reported in children or animals exposed to anesthesia during infancy, which is surprising, given the significant amount of damage to brain tissue reported in many animal studies. In this review, we discuss the relationship between the systems in the brain that mediate sensory input, spatial learning, and classical conditioning, and how these systems could be affected during anesthesia exposure. Based on previous reports, we conclude that anesthesia can induce structural, functional, and compensatory changes in both sensory and learning systems. Changes in myelination following anesthesia exposure were observed as well as the neurodegeneration in the gray matter across variety of brain regions. Disproportionate cell death between excitatory and inhibitory cells induced by anesthesia exposure can lead to a long-term shift in the excitatory/inhibitory balance, which affects both learning-specific networks and sensory systems. Anesthesia may directly affect synaptic plasticity which is especially critical to learning acquisition. However, sensory systems appear to have better ability to compensate for damage than learning-specific networks.

Current Evidence on Cell Death in Preterm Brain Injury in Human and Preclinical Models

Despite tremendous advances in neonatal intensive care over the past 20 years, prematurity carries a high burden of neurological morbidity lasting lifelong. The term encephalopathy of prematurity (EoP) coined by Volpe in 2009 encompasses all aspects of the now known effects of prematurity on the immature brain, including altered and disturbed development as well as specific lesional hallmarks. Understanding the way cells are damaged is crucial to design brain protective strategies, and in this purpose, preclinical models largely contribute to improve the comprehension of the cell death mechanisms. While neuronal cell death has been deeply investigated and characterized in (hypoxic–ischemic) encephalopathy of the newborn at term, little is known about the types of cell death occurring in preterm brain injury. Three main different morphological cell death types are observed in the immature brain, specifically in models of hypoxic–ischemic encephalopathy, namely, necrotic, apoptotic, and autophagic cell death. Features of all three types may be present in the same dying neuron. In preterm brain injury, description of cell death types is sparse, and cell loss primarily concerns immature oligodendrocytes and, infrequently, neurons. In the present review, we first shortly discuss the different main severe preterm brain injury conditions that have been reported to involve cell death, including periventricular leucomalacia (PVL), diffuse white matter injury (dWMI), and intraventricular hemorrhages, as well as potentially harmful iatrogenic conditions linked to premature birth (anesthesia and caffeine therapy). Then, we present an overview of current evidence concerning cell death in both clinical human tissue data and preclinical models by focusing on studies investigating the presence of cell death allowing discriminating between the types of cell death involved. We conclude that, to improve brain protective strategies, not only apoptosis but also other cell death (such as regulated necrotic and autophagic) pathways now need to be investigated together in order to consider all cell death mechanisms involved in the pathogenesis of preterm brain damage.

Effects of an MRI Try Without program on patient access

BACKGROUND

Pediatric patients are often sedated for magnetic resonance imaging (MRI) scans to ensure images are of diagnostic quality. However, access time for MRIs requiring sedation is often long due to high patient volumes and limited sedation resources.

OBJECTIVE

This study examined the effectiveness of an MRI Try Without sedation program to decrease the wait time for obtaining an MRI while simultaneously ensuring diagnostic-quality images.

MATERIALS AND METHODS

A retrospective chart review was performed on subjects who utilized the MRI Try Without program from April 2014 through June 2015 at a dedicated pediatric institution. Child life specialist preparations and access time (i.e. time from exam ordered to exam completed) were recorded in each patient's electronic medical record. MRI images were evaluated for image quality by a pediatric neuroradiologist.

RESULTS

A total of 134 patients participated in the MRI Try Without program (mean age: 6.9±1.7 years), all of whom received interventions from a child life specialist. The average number of days between when the order was placed and when the MRI was completed using the MRI Try Without program was 15.4±18.5 days, while the third-available appointment for sedation/anesthesia was 46.2 days (standard deviation [SD]±15.7 days). Nearly all patients received a "good" or "very good" image quality determination (87.3%) and only 5 (3.8%) patients were recommended for repeat examination for diagnostic-quality images.

CONCLUSION

Utilization of an MRI Try Without sedation program, with child life specialist interventions, decreased the wait time for obtaining an MRI while still providing diagnostic-quality images.

Children with congenital and childhood cataract require frequent follow-up visits and examinations in general anaesthesia: considerations for the strain on families

BACKGROUND

Children with cataract require frequent monitoring to detect complications, adjust refractive correction and treat amblyopia. This is time consuming for the families. The aim of the study was to evaluate how often children with cataract are seen as outpatients or under general anaesthesia during the first 7 years of life.

METHODS

We performed a retrospective chart review of all children with congenital and childhood cataract born between 2000 primo and 2017 seen at our institution. The cumulated number of outpatient visits and examinations and/or surgeries in general anaesthesia was extracted for age 1, 3, 5 and 7 years.

RESULTS

Children who had cataract surgery were seen significantly more often than children without surgery. During the first year of life, children with bilateral surgery had a median of nine outpatient visits, children with unilateral cataract had 11 and children without surgery had five outpatient visits. At 7 years of age, half of the children operated bilaterally before 1 year of age had undergone at least five procedures/examinations in general anaesthesia versus 1/4 of those with unilateral surgery and none of those without surgery. Children were seen less frequently with advancing age.

CONCLUSION

The management, treatment and follow-up of children with cataract are demanding, requiring frequent hospital visits and repeated examinations and/or surgical procedures in general anaesthesia over many years, but mainly during the first year of life. Surgical patients are more complex and require closer follow-up. This message is important to convey to the parents at the onset of the disease.

Hypothermia Following Spinal Anesthesia in an Infant: Potential Impact of Intravenous Dexmedetomidine and Intrathecal Clonidine

The α₂-adrenergic agonists (dexmedetomidine and clonidine) have been used in several different clinical scenarios in infants and children including sedation during mechanical ventilation, procedural sedation, supplementation of postoperative analgesia, prevention of emergence delirium, control of post-anesthesia shivering, treatment of withdrawal and prolonging of duration of neuraxial anesthesia. Hemodynamic effects including bradycardia and hypotension remain the predominant adverse effects reported with the α₂-adrenergic agonists. We report hypothermia following intravenous sedation with dexmedetomidine and spinal anesthesia with a combination of bupivacaine and clonidine in a 2-month-old infant. The potential mechanisms involved are reviewed, the causal relationship between hypothermia and α₂-adrenergic agonists is explored and interventions to avoid its development are presented.

Cognitive impairment and transcriptomic profile in hippocampus of young mice after multiple neonatal exposures to sevoflurane

Children with repeated inhalational anesthesia may develop cognitive disorders. This study aimed to investigate the transcriptome-wide response of hippocampus in young mice that had been exposed to multiple sevoflurane in the neonatal period. Mice received 3% sevoflurane for 2 h on postnatal day (PND) 6, 8, and 10, followed by arterial blood gas test on PND 10, behavioral experiments on PND 31–36, and RNA sequencing (RNA-seq) of hippocampus on PND 37. Functional annotation and protein-protein interaction analyses of differentially expressed genes (DEGs) and quantitative reverse transcription polymerase chain reaction (qPCR) were performed. Neonatal sevoflurane exposures induced cognitive and social behavior disorders in young mice. RNA-seq identified a total of 314 DEGs. Several enriched biological processes (ion channels, brain development, learning, and memory) and signaling pathways (oxytocin signaling pathway and glutamatergic, cholinergic, and GABAergic synapses) were highlighted. As hub-proteins, Pten was involved in nervous system development, synapse assembly, learning, memory, and behaviors, Nos3 and Pik3cd in oxytocin signaling pathway, and Cdk16 in exocytosis and phosphorylation. Some top DEGs were validated by qPCR. This study revealed a transcriptome-wide profile in mice hippocampus after multiple neonatal exposures to sevoflurane, promoting better understanding of underlying mechanisms and investigation of preventive strategies.

Initial clinical experience with high-pitch dual-source CT as a rapid technique for thoraco-abdominal evaluation in awake infants and young children

AIM

To evaluate dual-source high-pitch computed tomography (HPCT) imaging of the chest and abdomen as a rapid scanning technique to obtain diagnostic-quality imaging evaluation of infants and young children without sedation.

MATERIALS AND METHODS

Fifty-three paediatric patients (age 24.1±2 months) who underwent chest or abdomen HPCT (≥1.5) and standard pitch CT (SPCT, <1.5) on a dual-source 128-row multidetector CT system were included in the study. Image quality assessment was performed by two paediatric radiologists for diagnostic confidence, image artefacts, and image noise. Objective image noise was measured.

RESULTS

Most of the CT examinations were performed in children who were >1 year old (n=15 and n=20) followed by ≤1 year old (n=8 and n=10) in SPCT and HPCT, respectively. The mean radiation dose (SSDE) from HPCT was 1.96±1 mGy compared to 2.2±1 mGy for SPCT (p=0.3). No major artefacts were reported and overall image quality of all HPCT examinations was acceptable diagnostically. In addition, objective image noise values were not significantly different between HPCT compared with SPCT (11±3 versus 11±5, p=0.7).

CONCLUSION

Ultra-fast, HPCT can be performed without the need for sedation as a potential alternative to anaesthetised magnetic resonance imaging in infants and young children.

Evaluation of Neurotoxicity of Multiple Anesthesia in Children Using Visual Evoked Potentials

Objectives:

Anesthetic applications may cause increased neuronal damage in infants and children. Commonly cognitive or learning disability tests were used to investigate the neurological progress in children. Visual Evoked Potential is a gross electrical signal generated by the occipital regions of the cerebral cortex in response to visual stimulation and an objective assessment of brain function. In this study, to acquire more objective results, Visual Evoked Potential responses of children who had multiple exposures to anesthesia during the treatment of corrosive esophagitis were compared to children who have never received anesthesia before.

Methods:

In this prospective, single-blinded, randomized, controlled study, 25 children, who were admitted to our pediatric surgery clinic because of corrosive esophagitis and who received general anesthesia more than 15 times composed Group-P; 25 children, who admitted to our well-child-clinic and who had never received anesthesia before consisted Group-C. The flash and pattern VEP responses of both groups were measured at the electrophysiology laboratory without any anesthetic drug application. The VEP responses of children in Group-P were recorded at least three days after the last exposure to anesthesia.

Results:

Latencies and amplitudes of the N2 and P2 components of the pattern and flash VEP responses were statistically significantly different between the two groups (p=0.000).

Conclusion:

This study shows that in children who had repeated anesthetic applications VEP parameters are significantly altered. We believe that VEP responses may be a reliable objective criterion for the evaluation of anesthesia neurotoxicity.

Patent ductus arteriosus ligation on neurodevelopmental outcomes at corrected 2 years

Background

Our aim in this study was to evaluate whether very low birth weight infants (VLBWI) ligated for patent ductus arteriosus (PDA) were associated with worse neurodevelopmental outcomes at corrected 2 years. The ligated group was subdivided into ≤2 weeks of life (early) and ligated > 2 weeks of life (late) groups and compared the in-hospital morbidities and long term outcomes.

Methods

Between Dec 2013 and Dec 2015, VLBWI diagnosed with hs PDA were evaluated.

Results

Of the 191 VLBW infants with hs PDA, 28 (14.7%) infants had surgical ligation for PDA; 11 (39%) infants had EL and 17 (61%) infants had LL. Surgical ligation of hs PDA group had higher morbidities and mortality. Among the142 (83.0%) infants of 171 VLBWI with PDA survived, infants who were ligated had significantly lower scores of Bayley Scales of Infant and Toddler Development III at corrected age of 18 months. However, among the ligated group, there was little evidence of differences between the EL and LL groups. In a multivariable logistic regression analysis, only longer exposure of hs PDA and mechanical ventilation were consistently associated with worse neurodevelopmental outcomes.

Conclusion

Our results suggest that surgical ligation for hs PDA may not increase risk for poor neurodevelopmental outcomes at corrected 2 years of age. The early surgical ligation may not be a risk factor.

Comparison between epidural and opioid analgesia for infants undergoing major abdominal surgery

BACKGROUND

Epidural analgesia is considered optimal for postoperative pain management after major abdominal surgery. The potential to decrease anesthetic and opioid exposure is particularly desirable for infants, given their vulnerability to respiratory depression and concern for anesthetic neurotoxicity. We reviewed our experience with infants undergoing major abdominal surgery to determine if epidural catheter use decreased anesthetic and opioid exposure and improved postoperative analgesia.

METHODS

This retrospective cohort study included infants (<12 months) who underwent exploratory laparotomy, ureteral reimplantation, or bladder exstrophy repair between November 2011 and November 2014. Primary outcomes of anesthetic exposure (mean endtidal sevoflurane) and intraoperative opioid administration were compared between infants who received epidural catheters and those who did not. Secondary outcomes included postoperative pain and sedation scores and morphine equivalents administered 0-24 and 24-48 hours after surgery.

RESULTS

Of 158 eligible infants, 82 were included and 47 received epidurals. Patients with epidurals underwent bladder exstrophy repair (N = 9), ureteral reimplantation (N = 8), and exploratory laparotomy (N = 30). Infants with epidurals received less intraoperative fentanyl (2.6 mcg/kg (0,4.5) vs 3.3 mcg/kg (2.4,5.8), P = 0.019) and morphine (6% (3/47) vs 26% (9/35), P = 0.014) in univariate analysis. After controlling for age and emergency surgery, differences in long-acting opioid administration persisted, with significantly less morphine given in the epidural group (OR 0.181; 95% CI 0.035-0.925; P = 0.040). Mean endtidal sevoflurane concentrations were similar between groups. There was no significant difference in postoperative median morphine equivalents.

CONCLUSION

Placement of epidural catheters in infants undergoing major abdominal surgery is associated with decreased long-acting opioid requirements intraoperatively. Epidural placement does not preclude opioid exposure however, as opioids may be administered for indications other than nociceptive pain in the difficult-to-assess postoperative infant. Further prospective studies are warranted to better quantify the effect of epidural analgesia on intraoperative anesthetic exposure in infants.

Overexpression of phosphoprotein enriched in astrocytes 15 reverses the damage induced by propofol in hippocampal neurons

Propofol is a general anesthetic used in surgical operations. Phosphoprotein enriched in astrocytes 15(PEA15) was initially identified in astrocytes. The present study examined the role of PEA15 in the damage induced by propofol in hippocampal neurons. A model of hippocampal neuron damage was established using 50 µmol/l propofol. Cell viability, proliferation and apoptosis of hippocampal neurons were tested by Cell Counting Kit‑8 and flow cytometry. Western blotting and reverse transcription‑quantitative polymerase chain reaction analysis were performed to measure the expression levels of PEA15, and additional factors involved in apoptosis or in the signaling pathway downstream of PEA15. The present results suggested that propofol significantly decreased PEA15 expression levels in hippocampal neurons. Furthermore, overexpression of PEA15 significantly increased the cell viability and cell proliferation of cells treated with propofol. Additionally, PEA15 overexpression decreased apoptosis, which was promoted by propofol. Treatment with propofol significantly decreased the protein expression levels of pro‑caspase‑3, B‑cell lymphoma-2, phosphorylated extracellular signal‑regulated kinases (ERK)1/2, ribosomal S6 kinase 2 (RSK2) and phosphorylated cAMP responsive element binding protein 1 (CREB1). However, propofol upregulated active caspase‑3 and Bax expression levels. Notably, PEA15 overexpression was able to reverse the effects of propofol. Collectively, overexpression of PEA15 was able to attenuate the neurotoxicity of propofol in rat hippocampal neurons by increasing proliferation and repressing apoptosis via upregulation of the ERK‑CREB‑RSK2 signaling pathway.

Review on the use of zebrafish embryos to study the effects of anesthetics during early development

Over the years, the potential toxicity of anesthetics has raised serious concerns about its safe use during pregnancy. As evidence emerged from research in animal models, showing that some anesthetic drugs are potential teratogenic, the determination of the risk of exposures to anesthetic drugs at early life stages became mandatory. However, due to inaccessibility and ethical constrains related to experimental conditions, the use of early life stages in mammalian models is limited. In this regard, some animal and nonanimal models have been suggested to surpass mammalian use in experimentation. Among them, the zebrafish embryo test has been recognized as a promising alternative in toxicology research, as well as an inexpensive and practical test. Substantial information collected from developmental research following compounds exposure, has contributed to the application of zebrafish assays in research, although only a few studies have focused on the use of early life stages of zebrafish to evaluate the developmental effects of anesthetics. Based on the recent advances of science and technology, there is a clear potential for zebrafish early life stages to provide new insights into anesthetics teratogenicity. This review provides an overview of recent anesthesia research using zebrafish embryos, demonstrating its usefulness to the anesthesia field, discussing the recent findings on various aspects related to the effects of anesthetics during early life development and the strengths and limitations of this model system.

Anesthetics: from modes of action to unconsciousness and neurotoxicity

Modern anesthetic compounds and advanced monitoring tools have revolutionized the field of medicine, allowing for complex surgical procedures to occur safely and effectively. Faster induction times and quicker recovery periods of current anesthetic agents have also helped reduce health care costs significantly. Moreover, extensive research has allowed for a better understanding of anesthetic modes of action, thus facilitating the development of more effective and safer compounds. Notwithstanding the realization that anesthetics are a prerequisite to all surgical procedures, evidence is emerging to support the notion that exposure of the developing brain to certain anesthetics may impact future brain development and function. Whereas the data in support of this postulate from human studies is equivocal, the vast majority of animal research strongly suggests that anesthetics are indeed cytotoxic at multiple brain structure and function levels. In this review, we first highlight various modes of anesthetic action and then debate the evidence of harm from both basic science and clinical studies perspectives. We present evidence from animal and human studies vis-à-vis the possible detrimental effects of anesthetic agents on both the young developing and the elderly aging brain while discussing potential ways to mitigate these effects. We hope that this review will, on the one hand, invoke debate vis-à-vis the evidence of anesthetic harm in young children and the elderly, and on the other hand, incentivize the search for better and less toxic anesthetic compounds.

LncRNA MALAT1 is involved in sevoflurane-induced neurotoxicity in developing rats

OBJECTIVE

The purpose of this study is to uncover the effects of long chain noncoding RNA (lncRNA) metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) on sevoflurane-induced neurotoxicity in developing rats.

METHODS

Sevoflurane neurotoxicity model was established by sevoflurane treatment in 7-day-old Sprague-Dawley rats. The rats were treated with Sevo or MALAT1 small interfering RNA to detect the MALAT1 expression, pathological change, ultrastructure, neuronal apoptosis, expression of apoptosis-related proteins, expression of neurotrophic factors BDNF and NGF, spatial learning and memory function change, as well as neuron cell density of hippocampal tissues.

RESULTS

MALAT1 was highly expressed in hippocampus tissues of rats. Downregulation of MALAT1 alleviated the pathological change, improved the ultrastructure, inhibited apoptosis of neuronal cells, declined caspase 3 and Bax while elevated Bcl-2, BDNF and NGF, improved capability of spatial learning and memory, and increased density of hippocampal neurons in hippocampal tissues of sevoflurane-induced rats.

CONCLUSION

Suppression of MALAT1 can reduce the apoptosis of hippocampal neurons induced by sevoflurane anesthesia, improve the capability of spatial learning, and memory function and alleviate the loss of hippocampal nerve cells in developing rats. To a certain extent, it plays the role of protecting brain nerve cells.

Neonatal anesthesia impairs synapsin 1 and synaptotagmin 1, two key regulators of synaptic vesicle docking and fusion

Early exposure to anesthetics may interfere with synaptic development and lead to cognitive deficits. We previously demonstrated a decrease in vesicles docked at and within 100 nm from the presynaptic membrane in hippocampal nerve terminals of neonatal rats after anesthesia. Hence, we designed this study to assess the effects of neonatal anesthesia on synapsin 1 (Syn1) and synaptotagmin 1 (Syt1), two key regulators of vesicle docking and fusion. To test the link between changes in Syn1 and Syt1 and behavioral deficits observed after neonatal anesthesia, we also assessed retention memory and fear conditioning in adolescent rats after neonatal anesthesia. Pups received a combination of clinical anesthetics, then Syn1 and Syt1 mRNA and protein expression were determined at the peak (postnatal day 8, P8), part-way through (P12) and end of synaptogenesis (P24) in the CA1-subiculum by qPCR and western blotting. Anesthesia decreased Syn1 and Syt1 mRNA expression at P8 (P<0.01 and <0.001) and P12 (P=0.001 and 0.017), but not P24 (P=0.538 and 0.671), and impaired Syn1, p-Syn1, and Syt1 protein levels at P8 (P=0.038, 0.041, and 0.004, respectively), P12 (P<0.001, P=0.001, and P<0.0001), and P24 (P=0.025, 0.031, and 0.001). Anesthetic-challenged rats displayed deficient long-term retention memory (P=0.019) and hippocampus-dependent fear conditioning (P<0.001). These results suggest that anesthetics alter Syn1 and Syt1 during synapse assembly and maturation, raising the possibility that anesthetic interference with Syn1 and Syt1 could initiate changes in synaptic function that contribute to the cognitive deficits observed after neonatal anesthesia.

Disrupted folate metabolism with anesthesia leads to myelination deficits mediated by epigenetic regulation of ERMN

Background

Exposure to anesthetics during early life may impair cognitive functions. However, the underlying mechanisms remain largely unknown. We set out to determine effects of sevoflurane anesthesia on folate metabolism and myelination in young non-human primates, mice and children.

Methods

Young rhesus macaque and mice received 2.5 to 3% sevoflurane daily for three days. DNA and RNA sequencing and immunohistochemistry among others were used in the studies. We performed unbiased transcriptome profiling in prefrontal cortex of rhesus macaques and mice after the sevoflurane anesthesia. We constructed a brain blood barrier-crossing AAV-PHP.EB vector to harbor ERMN expression in rescue studies. We measured blood folate levels in children after anesthesia and surgery.

Findings

We found that thymidylate synthase (TYMS) gene was downregulated after the sevoflurane anesthesia in both rhesus macaque and mice. There was a reduction in blood folate levels in children after the anesthesia and surgery. Combined with transcriptome and genome-wide DNA methylation analysis, we identified that ERMN was the primary target of the disrupted folate metabolism. Myelination was compromised by the anesthesia in the young mice, which was rescued by systematic administration of folic acid or expression of ERMN in the brain through brain-specific delivery of the adeno-associated virus. Moreover, folic acid and expression of ERMN alleviated the cognitive impairment caused by the sevoflurane anesthesia in the mice.

Interpretation

General anesthesia leads to disrupted folate metabolism and subsequently defects in myelination in the developmental brain, and ERMN is the important target affected by the anesthesia via epigenetic mechanisms.

Avoidance of general anesthesia for circumcision in infants under 6 months of age using a modified Plastibell technique

PURPOSE

There is currently no gold standard for the type of analgesia or preferred circumcision technique in infants requiring circumcision after 1 month of age. Our study presents a modified Plastibell circumcision technique, which offers excellent surgical outcomes, and can be performed under local anesthesia until 6 months of age, thereby avoiding the risks of general anesthesia in delayed circumcision.

METHODS

This is a retrospective case series of 508 consecutive male infants between 1 and 6 months of age, from one institution, who all underwent circumcision under local anesthesia, performed by the same pediatric surgeon, from 2013 to 2018. The study parameters included postoperative complications such as re-operation for control of hemorrhage, wound infection, circumcision revision, and urethral meatotomy.

RESULTS

There were no re-operations for control of hemorrhage, no wound infections, and no circumcision revisions. One patient developed urethral meatal stenosis requiring urethral meatotomy.

CONCLUSION

Our modified Plastibell circumcision technique under local anesthesia is a safe and reproducible alternative for infants between 1 and 6 months of age, whose parents desire circumcision and wish to avoid general anesthesia.

In utero Exposure to Anesthetics Alters Neuronal Migration Pattern in Developing Cerebral Cortex and Causes Postnatal Behavioral Deficits in Rats

During fetal development, cerebral cortical neurons are generated in the proliferative zone along the ventricles and then migrate to their final positions. To examine the impact of in utero exposure to anesthetics on neuronal migration, we injected pregnant rats with bromodeoxyuridine to label fetal neurons generated at embryonic Day (E) 17 and then randomized these rats to 9 different groups receiving 3 different means of anesthesia (oxygen/control, propofol, isoflurane) for 3 exposure durations (20, 50, 120 min). Histological analysis of brains from 54 pups revealed that significant number of neurons in anesthetized animals failed to acquire their correct cortical position and remained dispersed within inappropriate cortical layers and/or adjacent white matter. Behavioral testing of 86 littermates pointed to abnormalities that correspond to the aberrations in the brain areas that are specifically developing during the E17. In the second set of experiments, fetal brains exposed to isoflurane at E16 had diminished expression of the reelin and glutamic acid decarboxylase 67, proteins critical for neuronal migration. Together, these results call for cautious use of anesthetics during the neuronal migration period in pregnancy and more comprehensive investigation of neurodevelopmental consequences for the fetus and possible consequences later in life.

In Situ Hinge Technique for the Frontal Bandeau for the Correction of Metopic Craniosynostosis Reduces Operative Time

BACKGROUND AND PURPOSE

Treatment of metopic craniosynostosis often involves bitemporal expansion of the anterior cranium. This report compares perioperative variables of a surgical technique in which the fronto-orbital bandeau is bent in situ to traditional fronto-orbital advancement and remodeling (FOAR).

METHOD/DESCRIPTION

Six patients undergoing the hinge technique were compared to the senior author's 6 most recent conventional FOARs. Study and control cohorts were reasonably well matched for age and sex; only those with nonsyndromic, single-suture metopic synostosis were included. Perioperative variables such as OR time, blood loss, hardware costs, length of stay, and perioperative complications were compared between groups using unpaired t tests.

RESULTS

Operative time was significantly decreased when the hinge technique was utilized, with a mean operative time of 159 ± 14.0 minutes for hinge patients and 193 ± 33.8 minutes for nonhinge patients (P = 0.049). Hardware was also significantly decreased from an average of 2.2 ± 1.0 plates and 35 ± 13.8 screws in nonhinge patients to 1 plate and 20 screws in each hinge patient (P < 0.02), for an average hardware saving of $2990 per hinge surgery (P = 0.019). Estimated blood loss, length of stay, and perioperative complications were not significantly different between groups. All patients in both groups had Whitaker 1 outcomes in short-term follow-up.

CONCLUSIONS

The hinge technique for the treatment of metopic synostosis is associated with a statistically significant decrease in operative time, hardware utilization, and hardware cost. Perioperative outcomes were similar between the hinge technique and traditional FOAR in the short term, and additional follow-up is needed to determine whether the 2 have similar long-term outcomes.

A survey of the dose of inhalational agents used to maintain anaesthesia in infants

BACKGROUND

Various animal studies suggest that currently used anaesthetics are toxic to the developing brain. Many reviews advise that the total anaesthetic drug exposure should be reduced but the dose usually used in clinical practice has not been clearly elucidated.

OBJECTIVES

To provide an overview of the dose ranges currently used in clinical practice during the maintenance phase of anaesthesia in infants undergoing anaesthesia for noncardiac surgery and diagnostic procedures.

DESIGN

A two-centre mixed prospective (London) and retrospective (Utrecht) observational cohort study.

SETTING

Two independent tertiary paediatric referral centres in March and November 2013; Great Ormond Street Hospital (GOSH), London, United Kingdom and Wilhelmina Children's Hospital, University Medical Center Utrecht (UMCU), The Netherlands.

PATIENTS

A total of 76 infants were included in the analysis, 38 infants from each hospital.

METHODS

Patients from GOSH were matched by procedure, age and weight with patients from the UMCU. The end-tidal concentrations of the inhalational agents were investigated from anaesthetic charts during the maintenance phase and corrected for the age-specific minimal alveolar concentration (MAC), expressed as a percentage from the MAC (%MAC).

RESULTS

Three different types of inhalational anaesthetics were used: sevoflurane, desflurane, isoflurane. The mean %MAC was 0.85. No significant differences in %MAC were found between GOSH and the UMCU (P = 0.329); the mean %MAC in GOSH was 0.87 and in the UMCU was 0.82. There was a significant increase in the %MAC in relation to age (slope = 0.036 MAC month, P < 0.001). Of all patients, 75% had an end-tidal concentration lower than 1 MAC. There was no significant effect of the use of analgesia on the end-tidal concentration of inhalational anaesthetics (P = 0.366).

CONCLUSION

The concentration of inhalational anaesthetics in %MAC increased with age and was lowest in neonates. Most young infants received inhalational anaesthetics at a concentration below 1 MAC, which accords with current guidance to minimise anaesthetic drug exposure but may have unintended consequences.

Application of molecular imaging technology in neurotoxicology research

Molecular imaging has been widely applied in preclinical research. Among these new molecular imaging modalities, microPET imaging can be utilized as a very powerful tool that can obtain the measurements of multiple biological processes in various organs repeatedly in a same subject. This review discusses how this new approach provides noninvasive biomarker for neurotoxicology research and summarizes microPET findings with multiple radiotracers on the variety of neurotoxicity induced by toxic agents in both the rodent and the nonhuman primate brain.