Anesthesia and the developing brain: are we getting closer to understanding the truth?

Fer-1 Protects against Isoflurane-Induced Ferroptosis in Astrocytes and Cognitive Impairment in Neonatal Mice

Early and prolonged exposure to anesthetic agents could cause neurodevelopmental disorders in children. Astrocytes, heavily outnumber neurons in the brain, are crucial regulators of synaptic formation and function during development. However, how general anesthetics act on astrocytes and the impact on cognition are still unclear. In this study, we investigated the role of ferroptosis and GPX4, a major hydroperoxide scavenger playing a pivotal role in suppressing the process of ferroptosis, and their underlying mechanism in isoflurane-induced cytotoxicity in astrocytes and cognitive impairment. Our results showed that early 6 h isoflurane anesthesia induced cognitive impairment in mice. Ferroptosis-relative genes and metabolic changes were involved in the pathological process of isoflurane-induced cytotoxicity in astrocytes. The level of GPX4 was decreased while the expression of 4-HNE and generation of ROS were elevated after isoflurane exposure. Selectively blocking ferroptosis with Fer-1 attenuated the abovementioned cytotoxicity in astrocytes, paralleling with the reverse of the changes in GPX4, ROS and 4-HNE secondary to isoflurane anesthesia. Fer-1 attenuated the cognitive impairment induced by prolonged isoflurane exposure. Thus, ferroptosis conduced towards isoflurane-induced cytotoxicity in astrocytes via suppressing GPX4 and promoting lipid peroxidation. Fer-1 was expected to be an underlying intervention for the neurotoxicity induced by isoflurane in the developing brain, and to alleviate cognitive impairment in neonates.

Global Trends and Hotspots in Pediatric Anesthetic Neurotoxicity Research: A Bibliometric Analysis From 2000 to 2023

The impact of general anesthetics on brain function development is one of the top frontier issues of public concern. However, little bibliometric analysis has investigated this territory systematically. Our study aimed to visualize the publications between 2000 and 2023 to inspire the trends and hotspots in anesthetic neurodevelopmental toxicity research. Publications from 2000 to 2023 were collected from the Web of Science Core Collection. CiteSpace was utilized to plot and analyze the network maps of countries, institutions, authors, journals, and keywords associated with these publications. A total of 864 publications, consisting of 786 original articles and 78 reviews, were extracted from 2000 to 2023. The annual publications have increased constantly over the past two decades. The USA and the People's Republic of China were the leading driving forces in this field. Harvard University was the most productive institution. Zhang Y published the most related articles, and Jevtovic-Todorovic V was mostly cited in this field. The most prolific journal was Pediatric Anesthesia, and the most frequently co-cited journal was Anesthesiology. Keywords were divided into nine clusters: "apoptosis", "propofol", "developing brain", "cognitive dysfunction", "neuronal cell degeneration", "brain", "neuroinflammation", "local anesthesia", and "oxygen therapy". The strongest citation bursts in earlier years were "learning disability", "cell death", and "cognitive function". The emerging trends in the coming years were "awake regional anesthesia", "behavioral outcome", and "infancy general anesthesia compared to spinal anesthesia". We conclude that anesthetic-induced neurotoxicity has received growing attention in the past two decades. Our findings evaluated the present status and research trends in this area, which may provide help for exploring further potential prospects on hot topics and frontiers.

Genistein Attenuates Isoflurane-Induced Neuroinflammation by Inhibiting TLR4-Mediated Microglial-Polarization in vivo and in vitro

Background

Isoflurane, a widely used anesthetic in surgery, has been found to induce neurotoxicity. In parallel, genistein is thought to attenuate isoflurane-induced neurotoxicity, although underlying molecular mechanisms are still unclear. In this study, we studied the protective effects of genistein on isoflurane-induced neuroinflammation in rats and BV2 cells.

Methods

Sprague-Dawley rat pups were exposed to 0.75% isoflurane for 6 hours at postnatal day 7 (P7), and genistein (20, 40, or 80 mg/kg/day) or saline administered from P3 to P15. Hippocampal single-cell suspensions were prepared and apoptosis analyzed by flow cytometry. mRNA expression was determined by RT-qPCR, while protein expression was assessed using Western blot, immunochemistry and immunofluorescence. TLR4 was knocked-out in BV2 cells through CRISPR-Cas9.

Results

Genistein treatment reduced isoflurane-induced apoptosis and inflammation in rat hippocampus. Importantly, genistein promoted M2 and suppressed M1 microglia polarization in rat hippocampus after stimulation with isoflurane. In addition, genistein reduced isoflurane-induced protein expression levels of TLR4, MyD88, TRAF6, p-TAK1, p-p38, p-ERK, p-IκBα and p-NF-κB in rat hippocampus. In BV2 cells exposed to isoflurane, genistein treatment decreased IL-1β, TNF-α, IL-6 and IL-8 mRNA expressions, promoted M2 and suppressed M1 microglia polarization. Similarly, genistein also decreased TLR4 protein levels in isoflurane-induced BV2 cells. However, genistein did not affect CD16, iNOS, CD206 and Arg1 protein levels in TLR4-KO BV2 cells exposed to isoflurane.

Conclusion

Genistein attenuates isoflurane-induced neurotoxicity by inhibiting TLR4-mediated microglial inflammation in vivo and in vitro.

New progress of isoflurane, sevoflurane and propofol in hypoxic-ischemic brain injury and related molecular mechanisms based on p75 neurotrophic factor receptor

Hypoxic ischemic brain injury (HIBI) is one of the most common clinical disorders, especially in neonates. The complex pathophysiology of HIBI is an important cause of disability and even death of patients, however, being without effective clinical treatments. Common anesthetics (such as isoflurane, propofol and sevoflurane) have an adverse impact on neuronal cells for HIBI via the regulation of p75 neurotrophic factor receptor (P75NTR). In order to protect the injured brains and study the effect of underlying treatments, it is particularly significant to understand and master the developmental mechanism of anesthetics for the occurrence of HIBI related molecular mechanisms. Therefore, this paper will mainly review the corresponding pathogenic and protective mechanisms about HIBI binding to the research progress of the role of P75NTR. In conclusion, the effects of neuroprotection and injured nerves are involved in the expression and activation of P75NTR, mainly increased P75NTR mRNA, protein levels and calpain-dependent for propofol, and inducing neuronal apoptosis for isoflurane and sevoflurane, and we look forward to that connection with P75NTR, common anaesthetic and HIBI may be a new direction of research and gain perfect outcomes in the future.

Effects of Early Exposure of Isoflurane on Chronic Pain via the Mammalian Target of Rapamycin Signal Pathway

Persistent post-surgical pain (PPSP) is a chronic pain condition, often with neuropathic features, that occurs in approximately 20% of children who undergo surgery. The biological basis of PPSP has not been elucidated. Anesthetic drugs can have lasting effects on the developing nervous system, although the clinical impact of this phenomenon is unknown. Here, we used a mouse model to test the hypothesis that early developmental exposure to isoflurane causes cellular and molecular alteration in the pain perception circuitry that causes a predisposition to chronic, neuropathic pain via a pathologic upregulation of the mammalian target of the rapamycin (mTOR) signaling pathway. Mice were exposed to isoflurane at postnatal day 7 and select cohorts were treated with rapamycin, an mTOR pathway inhibitor. Behavioral tests conducted 2 months later showed increased evidence of neuropathic pain, which did not occur in rapamycin-treated animals. Immunohistochemistry showed neuronal activity was chronically increased in the insular cortex, anterior cingulate cortex, and spinal dorsal horn, and activity was attenuated by rapamycin. Immunohistochemistry and western blotting (WB) showed a co-incident chronic, abnormal upregulation in mTOR activity. We conclude that early isoflurane exposure alters the development of pain circuits and has the potential to contribute to PPSP and/or other pain syndromes.

Achondroplasia: a comprehensive clinical review

Achondroplasia is the most common of the skeletal dysplasias that result in marked short stature (dwarfism). Although its clinical and radiologic phenotype has been described for more than 50 years, there is still a great deal to be learned about the medical issues that arise secondary to this diagnosis, the manner in which these are best diagnosed and addressed, and whether preventive strategies can ameliorate the problems that can compromise the health and well being of affected individuals. This review provides both an updated discussion of the care needs of those with achondroplasia and an exploration of the limits of evidence that is available regarding care recommendations, controversies that are currently present, and the many areas of ignorance that remain.

Galantamine reversed early postoperative cognitive deficit via alleviating inflammation and enhancing synaptic transmission in mouse hippocampus

Postoperative cognitive dysfunction (POCD) is commonly seen in patients undergoing major surgeries and may persist. Although neuroinflammation is one of the important contributors to the development of POCD, the mechanisms underlying POCD remain unclear. We performed stabilized tibial fracture operation in male mice. In comparison with sham mice (anesthesia only), the surgery mice exhibited cognitive deficits in a fear conditioning paradigm at postsurgery day 3-7, and increased numbers of microglia and elevated levels of pro-inflammatory cytokines (IL-1β, IL-6 and TNF-α) without change of anti-inflammatory cytokines (IL-4 and IL-10) in the hippocampus. Electrophysiological recordings from CA1 hippocampal neurons revealed that POCD mice exhibited impairment in AMPA receptor-mediated evoked excitatory postsynaptic currents (eEPSCs) without alteration in the rectification property of AMPA receptors. Interestingly, daily intraperitoneal administration of galantamine, an inhibitor of acetylcholinesterase, reversed cognitive dysfunction in surgery mice and attenuated accumulation of microglia and protein levels of IL-1β, IL-6 and TNF-α in the hippocampus. Additionally, galantamine potentiated AMPA receptor-mediated eEPSCs in the hippocampus more prominent in surgery mice than in sham mice. Therefore, enhancement of cholinergic tone in the hippocampus might be a therapeutic strategy for early POCD in terms of suppression of inflammation and normalization of excitatory synaptic transmission.

Neonatal anesthesia exposure impacts brain microRNAs and their associated neurodevelopmental processes

MicroRNAs (miRNAs), when subjected to environmental stimuli, can exhibit differential expression. As critical regulators of gene expression, differential miRNA expression has been implicated in numerous disorders of the nervous system. In this study, we focused on the effect of a general anesthetic, as an environmental stimulus, on miRNA expression of the developing brain. General anesthetics have potential long-lasting neurotoxic effects on the developing brain, resulting in behavioral changes in adulthood. We first carried out an unbiased profiling approach to examine the effect of single-episode neonatal general anesthetic, sevoflurance (sevo), exposure on miRNA expression of the brain. Neonatal sevo has a significant effect on the expression of specific miRNAs of the whole brain and the hippocampus that is both immediate – directly after neonatal treatment, as well as long-lasting - during adulthood. Functionally, neonatal sevo-associated miRNA gene-targets share potential neurodevelopmental pathways related to axon guidance, DNA transcription, protein phosphorylation and nervous system development. Our understanding on the role of miRNAs provides a putative epigenetic/molecular bridge that links neonatal general anesthetic’s effect with its associated functional change.

Upregulation of Cdh1 Attenuates Isoflurane-Induced Neuronal Apoptosis and Long-Term Cognitive Impairments in Developing Rats

Neonatal exposure to isoflurane can result in neuroapoptosis and persistent cognitive impairments. However, the underlying mechanisms remain elusive. Anaphase-promoting complex/cyclosome (APC/C) and its co-activator Cdh1 are E3 ubiquitin ligases that play important roles in the central nervous system, including in the regulation of neuronal survival, synaptic development, and mammalian learning and memory. However, whether APC/C-Cdh1 is involved in isoflurane-induced neurotoxicity in developing rats remains unclear. In this study, postnatal day-7 (P7) rat pups and primary hippocampal neurons were exposed to 2% isoflurane for 6 h. Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining was used to detect neuronal apoptosis, and the expression of proteins involved in apoptosis (cleaved caspase-3, Bax and Bcl-2) was assessed by western blot. The level of Cdh1 in the hippocampus was downregulated during isoflurane-induced neuroapoptosis. Cdh1-encoding lentivirus was transfected before isoflurane-treatment to increase the level of Cdh1. Our results showed that Cdh1 overexpression by a recombinant Cdh1-encoding lentivirus reduced isoflurane-induced neuronal apoptosis. Moreover, bilateral intra-hippocampal injection with Cdh1-encoding lentivirus attenuated long-term cognitive deficits after exposure to isoflurane in developing rats. Our study indicates that Cdh1 is an important target to prevent isoflurane-induced developmental neurotoxicity.

TREK-1 mediates isoflurane-induced cytotoxicity in astrocytes

Background

There are growing concerns that anaesthetic exposure can cause extensive apoptotic degeneration of neurons and the impairment of normal synaptic development and remodelling. However, little attention has been paid to exploring the possible cytotoxicity of inhalation anaesthetics, such as isoflurane, in astrocytes. In this research, we determined that prolonged exposure to an inhalation anaesthetic caused cytotoxicity in astrocytes, and we identified the underlying molecular mechanism responsible for this process.

Methods

Astrocytes were exposed to isoflurane, and astrocytic survival was then measured via LDH release assays, MTT assays, and TUNEL staining. TWIK-related potassium (K⁺) channel-1 (TREK-1) over-expression and knockdown models were also created using lentiviruses. The levels of TREK-1 and brain-derived neurotrophic factor (BDNF) were measured via Western blot and qRT-PCR.

Results

Prolonged exposure to isoflurane decreased primary astrocytic viability in a dose- and time-dependent manner. Moreover, with prolonged exposure to isoflurane, the TREK-1 level increased, and the BDNF level was reduced. TREK-1 knockdown promoted the survival of astrocytes and increased BDNF expression following isoflurane exposure.

Conclusions

Overdoses of and prolonged exposure to isoflurane induce cytotoxicity in primary astrocytes. TREK-1 plays an important role in isoflurane-induced cultured astrocytic cytotoxicity by down-regulating the expression of BDNF.

Tanshinone IIA Attenuates Sevoflurane Neurotoxicity in Neonatal Mice

BACKGROUND

Sevoflurane is the most widely used inhalational anesthetic in pediatric medicine. Despite this, sevoflurane has been reported to exert potentially neurotoxic effects on the developing brain. Clinical interventions and treatments for these effects are limited. Tanshinone IIA (Tan IIA), extracted from Salvia miltiorrhiza (Danshen), has been documented to alleviate cognitive decline in traditional applications. Therefore, we hypothesized that preadministration of Tan IIA may attenuate sevoflurane-induced neurotoxicity, suggesting that Tan IIA is a new and promising drug capable of counteracting the effects of cognitive dysfunction produced by general anesthetics.

METHODS

To test this hypothesis, neonatal C57 mice (P6) were exposed to 3% sevoflurane for 2 hours with or without Tan IIA pretreatment at a dose of 10 mg/kg or 20 mg/kg for 3 consecutive days. Cognitive behavior tests such as open field tests and fear conditioning were performed to evaluate locomotor and cognitive function at P31 and P32. At P8, other separate tests, including TdT mediated dUTP Nick End Labeling (TUNEL) assay, immunohistochemistry, Western blotting, enzyme-linked immunosorbent assay, and electron microscopy, were performed. The mean differences among groups were compared using 1-way analysis of variance followed by Bonferroni post hoc multiple comparison tests.

RESULTS

Repeated exposure to sevoflurane leads to significant cognitive impairment in mice, which may be explained by increased apoptosis, overexpression of neuroinflammatory markers, and changes in synaptic ultrastructure. Interestingly, preadministration of Tan IIA ameliorated these neurocognitive deficits, as shown by increased freezing percentages on the fear conditioning test (sevoflurane+Tan IIA [20 mg/kg] versus sevoflurane, mean difference, 19, 99% confidence interval for difference, 6.4-31, P < .0001, n = 6). The treatment also reduced the percentage of TUNEL-positive nuclei (sevoflurane versus sevoflurane+Tan IIA [20 mg/kg], 2.6, 0.73-4.5, P = .0004, n = 6) and the normalized expression of cleaved caspase-3 (sevoflurane versus sevoflurane+Tan IIA [20 mg/kg], 0.27, 0.02-0.51, P = .0046, n = 5). Moreover, it attenuated the production of the neuroinflammatory mediators interleukin (IL)-1β and IL-6 (normalized sevoflurane versus sevoflurane+Tan IIA [20 mg/kg]: IL-1β: 0.75, 0.47-1.0; P < .0001; IL-6: 0.66, 0.35-0.97; P < .0001; n = 10 per group). Finally, based on measurements of postsynaptic density, the treatment preserved synaptic ultrastructure (sevoflurane+Tan IIA [20 mg/kg] versus sevoflurane, 42, 20-66; P < .0001; n = 12 per group).

CONCLUSIONS

These results indicate that Tan IIA can alleviate sevoflurane-induced neurobehavioral abnormalities and may decrease neuroapoptosis and neuroinflammation.

The use of a dorsal double-wing flap without skin grafts for congenital syndactyly treatment: A STROBE compliant study

Numerous techniques have been developed that use various flaps to treat syndactyly. Skin grafts have often been used to cover remaining surgical defects. The long-term aim of surgery is to find new methods of separating the digits without using skin grafts. This paper describes a new surgical technique for the correction of simple, incomplete, and complete syndactyly. The technique consists of a dorsal double-wing flap to cover the newly created web space and zigzag incisions in the fingers, thus avoiding the use of skin grafts in this space. Overall, 35 web spaces in 24 patients were treated using this technique. Patient follow-up ranged from 6 months to nearly 5 years. There were no complications such as hematoma, infection or flap necrosis, and no fingers needed skin grafts after separation. The average operative time for each web space was approximately 45 minutes. Ninety-seven percent of patients treated with the dorsal double-wing flap procedure achieved good function, and superior cosmetic results following a single surgery. The technique is simple, rapid, safe, and easily performed and does not require the use of skin grafts.

Neurodevelopmental outcomes in infants undergoing general anesthesia

PURPOSE

Preclinical data strongly suggest that all agents used for general anesthesia (GA) have detrimental effects on the developing brain. However, clinical data are unclear. The purpose of this study was to use a cohort of infants who underwent GA and understand their neurodevelopmental outcomes.

METHODS

A cohort of infants who underwent GA was selected between 2010 and 2011, and a control group was created. Data regarding GA, procedures, and outcomes were collected in 2015. The cohort was divided into controls, GA without surgery, GA and surgery once, and multiple general anesthetics. Both univariate and multivariate analysis were performed, and a p value of less than 0.05 was considered significant.

RESULTS

457 patients, 121 controls, and 336 cases were included. Median follow-up was 5.1years. While developmental delay and the need for speech therapy were higher with GA, this did not correlate with the duration of GA. Patients having GA for MRI had the poorest outcomes. Multivariate analysis using combined binary outcome measures for psychiatric and neurologic outcomes did not show any significant difference for duration of anesthesia, age at anesthesia, or induction and maintenance agents.

CONCLUSIONS

These data suggest that GA during the first year of life may have few significant neurodevelopmental effects compared to controls. Additionally, the duration of GA did not correlate with neurodevelopmental outcomes.

TYPE OF STUDY

Retrospective Case Control Cohort Study.

LEVEL OF EVIDENCE

3 b (according to Oxford Center for EBM Levels of Evidence, March 2009, http://www.cebm.net/oxford-centre-evidence-based-medicine-levels-evidence-march-2009/).

Neonatal anesthetic neurotoxicity: Insight into the molecular mechanisms of long-term neurocognitive deficits

Mounting animal studies have demonstrated that almost all the clinically used general anesthetics could induce widespread neuroapoptosis in the immature brain. Alarmingly, some published findings have reported long-term neurocognitive deficits in response to early anesthesia exposure which deeply stresses the potential seriousness of developmental anesthetic neurotoxicity. However, the connection between anesthesia induced neuroapoptosis and subsequent neurocognitive deficits remains controversial. It should be noted that developmental anesthesia related neurotoxicity is not limited to neuroapoptosis. Early anesthesia exposure caused transient suppression of neurogenesis, ultrastructural abnormalities in synapse and alteration in the development of neuronal networks also could contribute to the long-term neurocognitive dysfunction. Understanding the mechanisms of developmental anesthetic neurotoxicity, especially by which anesthesia impairs brain function months after exposure, may lead to development of rational preventive and therapeutic strategies. The focus of present review is on some of those potential mechanisms that have been proposed for anesthesia induced cognitive decline.

Oral Clefts and Academic Performance in Adolescence: The Impact of Anesthesia-Related Neurotoxicity, Timing of Surgery, and Type of Oral Clefts

OBJECTIVE

Early life exposure to anesthesia and surgery is suspected to associate with cognitive impairment later in life. We compared academic achievement among adolescents with cleft lip only (CL), cleft palate only (CP), and cleft lip and cleft palate (CLP) with a noncleft control group to investigate whether outcome depends on timing and number of operations during childhood and/or type of oral cleft.

DESIGN

Nationwide register-based follow-up study.

SETTING

Danish birth cohort 1986 to 1990.

PARTICIPANTS

Five hundred fifty-eight children with isolated CL (n = 171), CLP (n = 222), or CP (n = 195), of which 509 children had been exposed to anesthesia and one or more cleft operation(s), and a 5% sample of the birth cohort (n = 14,677).

MAIN OUTCOME MEASURE(S)

Test score in the Danish standardized ninth-grade exam and proportion of nonattainment, defined as "results for ninth-grade exam unavailable." Data adjusted for sex, birth weight, parental age, and parental level of education.

RESULTS

Compared to controls, children with CL achieved higher scores (mean difference 0.12, 95% CI -0.05; 0.29) and children with CLP presented with lower scores (mean difference -0.06, 95% CI -0.21; 0.09), albeit both statistically insignificant. Children with CP achieved significantly lower scores, mean difference -0.20 (95% CI -0.38; -0.03). Odds ratios for nonattainment at final exam were: CL 0.79 (95% CI 0.46; 1.35), CLP 1.07 (95% CI 0.71; 1.61), CP 2.59 (95% CI 1.78; 3.76).

CONCLUSIONS

Oral cleft type rather than number and timing of anesthesia and operations associate to poorer academic performance. Although a potential neurotoxic effect due to anesthetic agents is not reflected in the data, it cannot be completely excluded.

Suppression of ERK phosphorylation through oxidative stress is involved in the mechanism underlying sevoflurane-induced toxicity in the developing brain

In animal models, neonatal exposure to general anesthetics significantly increased neuronal apoptosis with subsequent behavioral deficits in adulthood. Although the underlying mechanism is largely unknown, involvement of extracellular signal-regulated kinases (ERKs) is speculated since ERK phosphorylation is decreased by neonatal anesthetic exposure. Importance of ERK phosphorylation for neuronal development is underscored by our recent finding that transient suppression of ERK phosphorylation during the neonatal period significantly increased neuronal apoptosis and induced behavioral deficits. However, it is still unknown as to what extent decreased ERK phosphorylation contributes to the mechanism underlying anesthetic-induced toxicity. Here we investigated the causal relationship of decreased ERK phosphorylation and anesthetic-induced toxicity in the developing brain. At postnatal day 6 (P6), mice were exposed to sevoflurane (2%) or the blood-brain barrier-penetrating MEK inhibitor, α-[amino[(4-aminophenyl)thio]methylene]-2-(trifluoromethyl)benzeneacetonitrile (SL327) (50 mg/kg). Transient suppression of ERK phosphorylation by an intraperitoneal injection of SL327 at P6 significantly increased apoptosis similar to sevoflurane-induced apoptosis. Conversely, SL327 administration at P14 or P21 did not induce apoptosis, even though ERK phosphorylation was inhibited. Restoring ERK phosphorylation by administration of molecular hydrogen ameliorated sevoflurane-induced apoptosis. Together, our results strongly suggests that suppressed ERK phosphorylation is critically involved in the mechanism underlying anesthetic-induced toxicity in the developing brain.

Astrocytes Protect against Isoflurane Neurotoxicity by Buffering pro-brain-derived Neurotrophic Factor

BACKGROUND

Isoflurane induces cell death in neurons undergoing synaptogenesis via increased production of pro-brain-derived neurotrophic factor (proBDNF) and activation of postsynaptic p75 neurotrophin receptor (p75). Astrocytes express p75, but their role in neuronal p75-mediated cell death remains unclear. The authors investigated whether astrocytes have the capacity to buffer increases in proBDNF and protect against isoflurane/p75 neurotoxicity.

METHODS

Cell death was assessed in day in vitro (DIV) 7 mouse primary neuronal cultures alone or in co-culture with age-matched or DIV 21 astrocytes with propidium iodide 24 h after 1 h exposure to 2% isoflurane or recombinant proBDNF. Astrocyte-targeted knockdown of p75 in co-culture was achieved with small-interfering RNA and astrocyte-specific transfection reagent and verified with immunofluorescence microscopy. proBDNF levels were assessed by enzyme-linked immunosorbent assay. Each experiment used six to eight replicate cultures/condition and was repeated at least three times.

RESULTS

Exposure to isoflurane significantly (P < 0.05) increased neuronal cell death in primary neuronal cultures (1.5 ± 0.7 fold, mean ± SD) but not in co-culture with DIV 7 (1.0 ± 0.5 fold) or DIV 21 astrocytes (1.2 ± 1.2 fold). Exogenous proBDNF dose dependently induced neuronal cell death in both primary neuronal and co-cultures, an effect enhanced by astrocyte p75 inhibition. Astrocyte-targeted p75 knockdown in co-cultures increased media proBDNF (1.2 ± 0.1 fold) and augmented isoflurane-induced neuronal cell death (3.8 ± 3.1 fold).

CONCLUSIONS

The presence of astrocytes provides protection to growing neurons by buffering increased levels of proBDNF induced by isoflurane. These findings may hold clinical significance for the neonatal and injured brain where increased levels of proBDNF impair neurogenesis.

Brain maturation in neonatal rodents is impeded by sevoflurane anesthesia

BACKGROUND

A wealth of data shows neuronal demise after general anesthesia in the very young rodent brain. Herein, the authors apply proton magnetic resonance spectroscopy (1HMRS), testing the hypothesis that neurotoxic exposure during peak synaptogenesis can be tracked via changes in neuronal metabolites.

METHODS

1HMRS spectra were acquired in the brain (thalamus) of neonatal rat pups 24 and 48 h after sevoflurane exposure on postnatal day (PND) 7 and 15 and in unexposed, sham controls. A repeated measure ANOVA was performed to examine whether changes in metabolites were different between exposed and unexposed groups. Sevoflurane-induced neurotoxicity on PND7 was confirmed by immunohistochemistry.

RESULTS

In unexposed PND7 pups (N = 21), concentration of N-acetylaspartate (NAA; [NAA]) increased by 16% from PND8 to PND9, whereas in exposed PND7 pups (N = 19), [NAA] did not change and concentration of glycerophosphorylcholine and phosphorylcholine ([GPC + PCh]) decreased by 25%. In PND15 rats, [NAA] increased from PND16 to PND17 for both the exposed (N = 14) and the unexposed (N = 16) groups. Two-way ANOVA for PND7 pups demonstrated that changes over time observed in [NAA] (P = 0.031) and [GPC + PCh] (P = 0.024) were different between those two groups.

CONCLUSIONS

The authors demonstrated that normal [NAA] increase from PND8 to PND9 was impeded in sevoflurane-exposed rats when exposed at PND7; however, not impeded when exposed on PND15. Furthermore, the authors showed that noninvasive 1HMRS is sufficiently sensitive to detect subtle differences in developmental time trajectory of [NAA]. This is potentially clinically relevant because 1HMRS can be applied across species and may be useful in providing evidence of neurotoxicity in the human neonatal brain.

Effects of Physician-Based Preventive Oral Health Services on Dental Caries

BACKGROUND

Most Medicaid programs reimburse nondental providers for preventive dental services. We estimate the impact of comprehensive preventive oral health services (POHS) on dental caries among kindergarten students, hypothesizing improved oral health among students with medical visits with POHS.

METHODS

We conducted a retrospective study in 29,173 kindergarten students by linking Medicaid claims (1999-2006) with public health surveillance data (2005-2006). Zero-inflated regression models estimated the association between number of visits with POHS and (1) decayed, missing, and filled primary teeth (dmft) and (2) untreated decayed teeth while adjusting for confounding.

RESULTS

Kindergarten students with ≥4 POHS visits averaged an adjusted 1.82 dmft (95% confidence interval: 1.55 to 2.09), which was significantly less than students with 0 visits (2.21 dmft; 95% confidence interval: 2.16 to 2.25). The mean number of untreated decayed teeth was not reduced for students with ≥4 POHS visits compared with those with 0 visits.

CONCLUSIONS

POHS provided by nondental providers in medical settings were associated with a reduction in caries experience in young children but were not associated with improvement in subsequent use of treatment services in dental settings. Efforts to promote oral health in medical settings should continue. Strategies to promote physician-dentist collaborations are needed to improve continuity of care for children receiving dental services in medical settings.

CT angiography-guided single-stage release of adjacent webspaces in non-Apert syndactyly

We describe the CT angiography protocol and surgical technique utilized at our institution for single-stage release of adjacent web-spaces in non-Apert syndactyly. In a series of seven consecutive hands we analyse syndactyly anatomy, CT angiographic findings, operative details, and complications. Outcomes were assessed with a functional activity evaluation, range of motion, and a parental visual analogue scale. Seven affected hands in four patients underwent single-stage release of adjacent webspaces. In all cases, the CT angiogram correctly predicted the presence of at least one artery supplying each digit. There were no cases of digital ischemia or loss. Angiographically guided, single-stage release of adjacent webspaces is technically feasible and benefits patients by reducing the number of surgical stages and allowing complete release to be achieved at an earlier age compared with the standard multi-stage approach.

LEVEL OF EVIDENCE

IV.

Neurodevelopmental outcome after cardiac surgery utilizing cardiopulmonary bypass in children

Introduction:

Modulating the stress response and perioperative factors can have a paramount impact on the neurodevelopmental outcome of infants who undergo cardiac surgery utilizing cardiopulmonary bypass.

Materials and Methods:

In this single center prospective follow-up study, we evaluated the impact of three different anesthetic techniques on the neurodevelopmental outcomes of 19 children who previously underwent congenital cardiac surgery within their 1^st year of life. Cases were done from May 2011 to December 2013. Children were assessed using the Stanford-Binet Intelligence Scales (5^th edition). Multiple regression analysis was used to test different parental and perioperative factors that could significantly predict the different neurodevelopmental outcomes in the entire cohort of patients.

Results:

When comparing the three groups regarding the major cognitive scores, a high-dose fentanyl (HDF) patients scored significantly higher than the low-dose fentanyl (LDF) + dexmedetomidine (DEX) (LDF + DEX) group in the quantitative reasoning scores (106 ± 22 vs. 82 ± 15 P = 0.046). The bispectral index (BIS) value at the end of surgery for the -LDF group was significantly higher than that in LDF + DEX group (P = 0.011). For the entire cohort, a strong correlation was seen between the standard verbal intelligence quotient (IQ) score and the baseline adrenocorticotropic hormone level, the interleukin-6 level at the end of surgery and the BIS value at the end of the procedure with an R² value of 0.67 and P < 0.04. There was an inverse correlation between the cardiac Intensive Care Unit length of stay and the full-scale IQ score (R = 0.4675 and P 0.027).

Conclusions:

Patients in the HDF group demonstrated overall higher neurodevelopmental scores, although it did not reach statistical significance except in fluid reasoning scores. Our results may point to a possible correlation between blunting the stress response and improvement of the neurodevelopmental outcome.

Pain care for patients with epidermolysis bullosa: best care practice guidelines

BACKGROUND

Inherited epidermolysis bullosa (EB) comprises a group of rare disorders that have multi-system effects and patients present with a number of both acute and chronic pain care needs. Effects on quality of life are substantial. Pain and itching are burdensome daily problems. Experience with, and knowledge of, the best pain and itch care for these patients is minimal. Evidence-based best care practice guidelines are needed to establish a base of knowledge and practice for practitioners of many disciplines to improve the quality of life for both adult and pediatric patients with EB.

METHODS

The process was begun at the request of Dystrophic Epidermolysis Bullosa Research Association International (DEBRA International), an organization dedicated to improvement of care, research and dissemination of knowledge for EB patients worldwide. An international panel of experts in pain and palliative care who have extensive experience caring for patients with EB was assembled. Literature was reviewed and systematically evaluated. For areas of care without direct evidence, clinically relevant literature was assessed, and rounds of consensus building were conducted. The process involved a face-to-face consensus meeting that involved a family representative and methodologist, as well as the panel of clinical experts. During development, EB family input was obtained and the document was reviewed by a wide variety of experts representing several disciplines related to the care of patients with EB.

RESULTS

The first evidence-based care guidelines for the care of pain in EB were produced. The guidelines are clinically relevant for care of patients of all subtypes and ages, and apply to practitioners of all disciplines involved in the care of patients with EB. When the evidence suggests that the diagnosis or treatment of painful conditions differs between adults and children, it will be so noted.

CONCLUSIONS

Evidence-based care guidelines are a means of standardizing optimal care for EB patients, whose disease is often times horrific in its effects on quality of life, and whose care is resource-intensive and difficult. The guideline development process also highlighted areas for research in order to improve further the evidence base for future care.

Propofol exposure in pregnant rats induces neurotoxicity and persistent learning deficit in the offspring

Propofol is a general anesthetic widely used in surgical procedures, including those in pregnant women. Preclinical studies suggest that propofol may cause neuronal injury to the offspring of primates if it is administered during pregnancy. However, it is unknown whether those neuronal changes would lead to long-term behavioral deficits in the offspring. In this study, propofol (0.4 mg/kg/min, IV, 2 h), saline, or intralipid solution was administered to pregnant rats on gestational day 18. We detected increased levels of cleaved caspase-3 in fetal brain at 6 h after propofol exposure. The neuronal density of the hippocampus of offspring was reduced significantly on postnatal day 10 (P10) and P28. Synaptophysin levels were also significantly reduced on P28. Furthermore, exploratory and learning behaviors of offspring rats (started at P28) were assessed in open-field trial and eight-arm radial maze. The offspring from propofol-treated dams showed significantly less exploratory activity in the open-field test and less spatial learning in the eight-arm radial maze. Thus, this study suggested that propofol exposure during pregnancy in rat increased cleaved caspsase-3 levels in fetal brain, deletion of neurons, reduced synaptophysin levels in the hippocampal region, and persistent learning deficits in the offspring.

Brain regional vulnerability to anaesthesia-induced neuroapoptosis shifts with age at exposure and extends into adulthood for some regions

BACKGROUND

General anaesthesia facilitates surgical operations and painful interventions in millions of patients every year. Recent observations of anaesthetic-induced neuronal cell death in newborn animals have raised substantial concerns for young children undergoing anaesthesia. However, it remains unclear why some brain regions are more affected than others, why certain neurones are eliminated while neighbouring cells are seemingly unaffected, and what renders the developing brain exquisitely vulnerable, while the adult brain apparently remains resistant to the phenomenon.

METHODS

Neonatal (P7), juvenile (P21), and young adult mice (P49) were anaesthetized with 1.5% isoflurane. At the conclusion of anaesthesia, activated cleaved caspase 3 (AC3), a marker of apoptotic cell death, was quantified in the neocortex (RSA), caudoputamen (CPu), hippocampal CA1 and dentate gyrus (DG), cerebellum (Cb), and olfactory bulb (GrO) and compared with that found in unanaesthetized littermates.

RESULTS

After anaesthetic exposure, increased AC3 was detected in neonatal mice in RSA (11-fold, compared with controls), CPu (10-fold), CA1 (three-fold), Cb (four-fold), and GrO (four-fold). Surprisingly, AC3 continued to be elevated in the DG and GrO of juvenile (15- and 12-fold, respectively) and young adult mice (two- and four-fold, respectively).

CONCLUSIONS

The present study confirms the findings of previous studies showing peak vulnerability to anaesthesia-induced neuronal cell death in the newborn forebrain. It also shows sustained susceptibility into adulthood in areas of continued neurogenesis, substantially expanding the previously observed age of vulnerability. The differential windows of vulnerability among brain regions, which closely follow regional peaks in neurogenesis, may explain the heightened vulnerability of the developing brain because of its increased number of immature neurones.

Long-term effects of neonatal single or multiple isoflurane exposures on spatial memory in rats

General anesthetics are neurotoxic to neonatal rodents and non-human primates. Neonatal exposure to general anesthetics has been associated with long-term cognitive deficits in animal models. Some data from humans are consistent with long-term deleterious effects of anesthetic exposure early in life on cognitive development, with multiple exposures to general anesthetics being particularly damaging. We sought to determine whether repeated exposure of neonatal rats to anesthesia was associated with long-term cognitive impairments and whether the magnitude of impairments was greater than that resulting from a single exposure. Male or female Long–Evans rat pups were exposed to 1.8% isoflurane for 2 h on postnatal day (P) 7, or for 2 h each on P7, P10, and P13. Testing in a spatial working memory task began on P91. Rats that were repeatedly exposed to isoflurane were impaired relative to controls in the spatial working memory task. Male rats that received a single exposure to isoflurane showed an unexpected facilitation in spatial memory performance. These results support the hypothesis that multiple neonatal exposures to general anesthesia are associated with greater long-term cognitive impairment than a single exposure. The findings are congruent with human epidemiological studies reporting long-term cognitive impairments following multiple but not single general anesthetics early in life.

Resolution of biliary stricture after living donor liver transplantation in a child by percutaneous trans-hepatic cholangiography and drainage: a case report

INTRODUCTION

Intra-hepatic cholestasis arising from biliary strictures is a frequent complication in pediatric patients after liver transplantation. Minimally invasive procedures such as percutaneous drainage placement and balloon dilation are the preferred diagnostic and therapeutic modalities.

CASE PRESENTATION

We report the case of a 12-month-old Caucasian boy with biliary atresia who was initially treated with hepatoportoenterostomy. In the following months, he developed biliary cirrhosis, accompanied by cystic bile retention, recurrent bile duct infections and malabsorption. Six months after the initial surgical intervention, he underwent living donor liver transplantation. Within two months, the hepatico-jejunostomy became occluded leading to progressive intra-hepatic cholestasis. Under sonographic guidance, external drainage of bile was accomplished by percutaneous trans-hepatic cholangiography and drainage. In total, our patient underwent 12 interventions under general anesthesia until balloon dilatation of the hepatico-jejunostomy was successfully performed. Finally, our patient's general condition improved and he gained weight.

CONCLUSIONS

Minimally invasive techniques are preferred to surgical revisions and justify even multiple attempts. Interventions under general anesthesia, though not without risks, are still reasonable. Co-operation with parents and multidisciplinary approach to complication management by the involved surgeon, radiologist, pediatrician and anesthesiologist are important.

Perioperative delirium and its relationship to dementia

A number of serious clinical cognitive syndromes occur following surgery and anesthesia. Postoperative delirium is a behavioral syndrome that occurs in the perioperative period. It is diagnosed through observation and characterized by a fluctuating loss of orientation and confusion. A distinct syndrome that requires formalized neurocognitive testing is frequently referred to as postoperative cognitive dysfunction (POCD). There are serious concerns as to whether either postoperative delirium or postoperative cognitive dysfunction leads to dementia. These concerns are reviewed in this article.

Anesthetics interfere with the polarization of developing cortical neurons

Numerous studies from the clinical and preclinical literature indicate that general anesthetic agents have toxic effects on the developing brain, but the mechanism of this toxicity is still unknown. Previous studies have focused on the effects of anesthetics on cell survival, dendrite elaboration, and synapse formation, but little attention has been paid to possible effects of anesthetics on the developing axon. Using dissociated mouse cortical neurons in culture, we found that isoflurane delays the acquisition of neuronal polarity by interfering with axon specification. The magnitude of this effect is dependent on isoflurane concentration and exposure time over clinically relevant ranges, and it is neither a precursor to nor the result of neuronal cell death. Propofol also seems to interfere with the acquisition of neuronal polarity, but the mechanism does not require activity at GABAA receptors. Rather, the delay in axon specification likely results from a slowing of the extension of prepolarized neurites. The effect is not unique to isoflurane as propofol also seems to interfere with the acquisition of neuronal polarity. These findings demonstrate that anesthetics may interfere with brain development through effects on axon growth and specification, thus introducing a new potential target in the search for mechanisms of pediatric anesthetic neurotoxicity.

Preclinical research into the effects of anesthetics on the developing brain: promises and pitfalls

Every year millions of children are treated with anesthetics and sedatives to alleviate pain and distress during invasive procedures. Accumulating evidence suggests the possibility for deleterious effects on the developing brain. This has led to significant concerns among pediatric anesthesiologists and to the formation of the Pediatric Anesthesia NeuroDevelopmental Assessment (PANDA) group and its biannual symposium. Not surprisingly, the majority of the data in this field have thus far been derived through laboratory research. Accordingly, this review summarizes the current state of animal research in this field, introduces some of the findings presented at the PANDA symposium, and addresses some of the difficulties in translating these findings to pediatric anesthesia practice, as discussed during the symposium. The symposium participants' consensus was that significant preclinical and clinical research efforts are still needed to investigate this important concern for child health.

Hippocampal glutamate level and glutamate aspartate transporter (GLAST) are up-regulated in senior rat associated with isoflurane-induced spatial learning/memory impairment

Postoperative cognitive decline is a clinical concern especially for senior patients. It is generally recognized that glutamatergic system plays a crucial role in the physiopathologic process of neurocognitive deterioration. However, alterations of glutamatergic system in prolonged isoflurane-induced learning/memory decline are still unclear. This study investigates the question whether glutamate concentration and corresponding transporters or receptors display any alternations in aged rat suffering from isoflurane-induced learning/memory impairment. 111 male Sprague-Dawley rats (>18 months) were randomly divided into two main groups: hippocampal microdialysis group (n = 38) and western blotting group (n = 73). Each group was subdivided into three subgroups including (1) control subgroup (n = 6 and 10, receiving no behavioral trial, anesthesia or air exposure); (2) air-exposed subgroup (n = 7 and 15, receiving behavioral trial and air exposure but not anesthesia); (3) isoflurane anesthesia subgroup (n = 25 and 48, receiving both behavioral trial and anesthesia). The isoflurane-exposed rats were further divided into a learning/memory-impaired subgroup and a non-learning/memory-impaired subgroup according to their behavioral performance, which was measured using Morris water maze. Hippocampal glutamate concentrations in microdialysates were determined by high-performance liquid chromatography. Expression levels of GLAST, GLT-1, NMDAR1, NMDAR2A/B, AMPAR and tau in hippocampus were assessed via quantitative Western blotting. The incidences of learning/memory impairment of isoflurane-exposed rats in hippocampal microdialysis group and western blotting group were 12.0 (3/25) and 10.4 % (5/48) respectively. The intra-anesthesia hippocampal glutamate levels were significantly lower than those of non-anesthesized rats. The learning/memory-impaired rats showed a long-lasting increased glutamate level from 24 h after isoflurane exposure to the end of the study, but the other 22 isoflurane-exposed rats did not. The learning/memory-impaired subgroup displayed a significantly higher GLAST level than the other three subgroups (p = 0.026, 0.02 and 0.032 respectively). The expression levels of GLT-1, NMDAR1, NMDAR2A/B and AMPAR of every subgroup were comparable. We found a continuous raised hippocampal glutamate and an up-regulation of GLAST rather than GLT-1, NMDAR1, NMDAR2A/B, AMPAR or tau in hippocampus of aged rats associated with isoflurane-induced learning/memory impairment.

Early childhood caries screening tools: a comparison of four approaches

BACKGROUND

Early childhood caries (ECC) is prevalent and consequential. Risk assessment tools have been proposed that can be used to identify children who require intensive interventions. In this study, the authors compare four approaches for identifying children needing early and intensive intervention to prevent or minimize caries experience for their accuracy and clinical usefulness.

METHODS

The authors screened 229 predominantly low-income Hispanic children younger than 3 years with ECC and 242 without ECC by using the American Academy of Pediatric Dentistry's Caries-risk Assessment Tool (CAT) and the optional screening measure of culturing Streptococcus mutans. The authors compared four approaches (CAT, CAT minus socioeconomic status, CAT minus socioeconomic status plus mutans streptococci [MS] and MS alone) for accuracy and clinical usefulness.

RESULTS

The results of the CAT demonstrated high sensitivity (100.0 percent) and negative predictive value (NPV) (100.0 percent) but low specificity (2.9 percent) and positive predictive value (PPV) (49.4 percent). The MS culture alone had the highest combination of accuracy and clinical usefulness (sensitivity, 86.5 percent; specificity, 93.4 percent; PPV, 92.5 percent; NPV, 87.9 percent). When we removed the socioeconomic status element, the CAT's performance improved.

CONCLUSIONS

Salivary culture of MS alone in a population of young, low-income Hispanic children outperformed the CAT and variations on the CAT for test accuracy (sensitivity and specificity) and clinical usefulness (predictive values).

CLINICAL IMPLICATIONS

Screening for ECC by using salivary MS cultures and variations on the CAT are promising approaches for identifying children who need early and intensive intervention to prevent or minimize caries experience.

Neurological injury and anesthetic neurotoxicity following neonatal cardiac surgery: does the head rule the heart or the heart rule the head?

The improvements in care of children with heart disease have resulted in a major decrease in mortality and increased attention to adverse events and quality of survival. There is important neurological morbidity in children with congenital heart disease. Some problems such as stroke or seizure may be immediately apparent, but others, such as learning disability and motor delay emerge over time. The etiology is multifactorial and includes genetic, procedural and social causes. Only some factors are modifiable. Over the last decade, evidence has been presented that anesthetic drugs may be a potential cause of CNS morbidity. Neonates and infants may be particularly vulnerable to this. The purpose of this article is to describe the multiple known causes of neurodevelopmental impairment in children with heart disease, including anesthetic agents, and to explore the relationship between congenital heart disease and its treatment in this regard.