Neurotoxicity versus Neuroprotection of Anesthetics: Young Children on the Ropes?

Effects of Subchronic Propofol Administration on the Proliferation and Differentiation of Neural Stem Cells in Rat Hippocampus

Background

Although controversial, experimental data suggest the use of propofol may be associated with neurotoxicity. The mechanisms responsible for propofol neurotoxicity in animals are not yet clear.

Objective

This study aimed to determine the effects of propofol on the proliferation of neural stem cells in rat hippocampus and the mechanisms underlying these effects.

Methods

Forty-five adult male Sprague-Dawley rats were randomly divided into 5 groups: Control (N group), intralipid (V group), 30 mg/kg propofol (Prop30 group), 60 mg/kg propofol (Prop60 group), and 120 mg/kg propofol (Prop120 group). The rats in all groups received 5, once daily intraperitoneal injections. For each of the 5 days, the N group received 6 mL/kg normal saline, the V group received 6 mL/kg fat emulsion, the Prop30 group received 30 mg/kg propofol, the Prop60 group received 60 mg/kg propofol, and the Prop120 group received 120 mg/kg propofol. Memory function was scored daily using the Morris water maze test. Immunofluorescence staining was used to histologically monitor the proliferation and differentiation of the rats' hippocampal neural stem cells, and real time quantitative polymerase chain reaction and Western blotting were used to determine the expression of Notch3, Hes1, and Hes5.

Results

Compared with the N group, the Prop120 group exhibited reduced learning and memory, whereas there were no significant differences for the Prop60 group. The number of β-tubulin III⁺ cells increased in the Prop60 group, but decreased in the Prop120 group. Compared with the N group, the relative expression of Notch3 and Hes5 increased significantly in the Prop60 group, whereas this expression decreased in the Prop120 group.

Conclusions

These data demonstrate that repeated, subchronic (5 days) intraperitoneal injections of 60 mg/kg propofol can effectively promote rat hippocampal neural stem cells proliferation and differentiation, and that this is likely mediated by its effects on the Notch3-Hes5 pathway.

Pediatric spinal anesthesia at a tertiary care hospital: Eleven years after

BACKGROUND

Pediatric spinal anesthesia is an old technique whose use is not widespread, in spite of reducing the risk of cardiorespiratory events (hypoxemia, bradycardia, and hypotension) associated with general anesthesia, especially in neonates and infants. This retrospective cohort study aimed to assess the safety and effectiveness of the pediatric spinal anesthesia program at our tertiary care hospital over 11 years.

METHODS

Two hundred children, between 8 days and 13 years of age, who underwent lower body surgery under spinal anesthesia from May 2010 to July 2021 were included. Demographic and procedural data were collected, and success, failure, and complication rates calculated.

RESULTS

The success rate was 97.5% (n = 195). The incidence of complications was 2% (n = 4). They were 2 cases of intraoperative hypoxemia and 2 cases of postoperative postdural puncture headache , and they quickly resolved with no sequelae.

CONCLUSION

Pediatric spinal anesthesia is a safe and effective technique with good acceptance among anesthesiologists. Thus, the implementation of a pediatric spinal anesthesia program at a tertiary care hospital is feasible and affordable.

Opioid-free anesthesia with interfascial dexmedetomidine in a high-risk infant

Despite the advances in pediatric anesthesia, infants have higher mortality and critical incidents rates than children, especially ex-prematures and those with comorbidity. We present the case of a high-risk infant who underwent elective laparoscopic gastrostomy under opioid-free anesthesia (OFA) combined with transversus abdominis plane (TAP) block with Dexmedetomidine (DEX). Perioperative opioids were entirely avoided, and intraoperative anesthetics and postoperative analgesic were considerably reduced. The infant showed cardiorespiratory stability and optimal analgesia during the uneventful procedure and the postoperative period. We consider OFA and TAP block with DEX a safe and effective anesthetic combination for high-risk infants.

Conflicting Actions of Inhalational Anesthetics, Neurotoxicity and Neuroprotection, Mediated by the Unfolded Protein Response

Preclinical studies have shown that exposure of the developing brain to inhalational anesthetics can cause neurotoxicity. However, other studies have claimed that anesthetics can exert neuroprotective effects. We investigated the mechanisms associated with the neurotoxic and neuroprotective effects exerted by inhalational anesthetics. Neuroblastoma cells were exposed to sevoflurane and then cultured in 1% oxygen. We evaluated the expression of proteins related to the unfolded protein response (UPR). Next, we exposed adult mice in which binding immunoglobulin protein (BiP) had been mutated, and wild-type mice, to sevoflurane, and evaluated their cognitive function. We compared our results to those from our previous study in which mice were exposed to sevoflurane at the fetal stage. Pre-exposure to sevoflurane reduced the expression of CHOP in neuroblastoma cells exposed to hypoxia. Anesthetic pre-exposure also significantly improved the cognitive function of adult wild-type mice, but not the mutant mice. In contrast, mice exposed to anesthetics during the fetal stage showed cognitive impairment. Our data indicate that exposure to inhalational anesthetics causes endoplasmic reticulum (ER) stress, and subsequently leads to an adaptive response, the UPR. This response may enhance the capacity of cells to adapt to injuries and improve neuronal function in adult mice, but not in developing mice.

Spinal Anesthesia for Pediatric Laparoscopic Hernia Repair: A Case Report

Spinal anesthesia is practical and safe in infants and toddlers and prevents perioperative complications including cardiorespiratory instability and apnea. Other perioperative advantages include reduced time from surgery completion to operating room exit and first feed. This article presents the case of an ex-premature infant who underwent laparoscopic inguinal hernia repair under spinal anesthesia. The infant remained calm and stable throughout the uneventful procedure and postoperative period. Spinal anesthesia may be feasible for laparoscopic herniotomy when pneumoperitoneum pressure and operative time are restricted to 8 mm Hg and 60 minutes, respectively, with sensory level at T10 or higher.

Autophagy is involved in sevoflurane-induced developmental neurotoxicity in the developing rat brain

BACKGROUND

Sevoflurane can induce neonatal wide neurodegenerative and serious deficit to space learning tasks in rodents, however, the specific mechanism is still unclear. At present, the study tried to explore the possible role of autophagy in sevoflurane-induced neurotoxicity through observing the changes in the levels of autophagy in the newborn SD rat hippocampus tissue after sevoflurane exposure.

METHODS

We used seventy-two SD rats of seven days receiving sevoflurane exposure to explore hippocampus neuron autophagy and apoptosis.

RESULTS

Our results indicated that sevoflurane increased the levels of Beclin-1, microtubule-associated protein light chain 3II protein and decreased sequestosome 1 levels in a time-dependent manner by Western blot in the developing brain. These results were further substantiated by transmission electron microscopy, quantitative reverse transcription polymerase chain reaction, immunohistochemistry and immunofluorescence. Rapamycin, an activator of autophagy, increased the levels of Beclin-1and LC3-II protein, meanwhile, 3-methyladenine, an inhibitor of autophagy, decreased Beclin-1and LC3-II protein levels.

CONCLUSION

Taken together, autophagy may be involved in sevoflurane-induced developmental neurotoxicity and promoting protective autophagy may be a potential way of preventing developmental sevoflurane-induced neurotoxicity.