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

AIMS: Numerous studies on animals have shown that exposure to general anesthetics in infant stage may cause neurocognitive impairment. However, the exact mechanism is not clear. The dysfunction of iron metabolism can cause neurodevelopmental disorders. Therefore, we investigated the effect of iron metabolism disorder induced by sevoflurane (Sev) on cognitive function and the proliferation of neural precursor cells (NPCs) and neural stem cells (NSCs) in infant mice. METHODS: C57BL/6 mice of postnatal day 14 and neural stem cells NE4C were treated with 2% Sev for 6 h. We used the Morris water maze (MWM) to test the cognitive function of infant mice. The proliferation of NPCs was measured using bromodeoxyuridine (BrdU) label and their markers Ki67 and Pax6 in infant brain tissues 12 h after anesthesia. Meanwhile, we used immunohistochemical stain, immunofluorescence assay, western blot, and flow cytometer to evaluate the myelinogenesis, iron levels, and cell proliferation in cortex and hippocampus or in NE4C cells. RESULTS: The results showed that Sev significantly caused cognitive deficiency in infant mice. Further, we found that Sev inhibited oligodendrocytes proliferation and myelinogenesis by decreasing MBP and CC-1 expression and iron levels. Meanwhile, Sev also induced the iron deficiency in neurons and NSCs by downregulating FtH and FtL expression and upregulating the TfR1 expression in the cortex and hippocampus, which dramatically suppressed the proliferation of NSCs and NPCs as indicated by decreasing the colocalization of Pax6+ and BrdU+ cells, and caused the decrease in the number of neurons. Interestingly, iron supplementation before anesthesia significantly improved iron deficiency in cortex and hippocampus and cognitive deficiency induced by Sev in infant mice. Iron therapy inhibited the decrease of MBP expression, iron levels in neurons and oligodendrocytes, and DNA synthesis of Pax6+ cells in hippocampus induced by Sev. Meanwhile, the number of neurons was partially recovered in hippocampus. CONCLUSION: The results from the present study demonstrated that Sev-induced iron deficiency might be a new mechanism of cognitive impairment caused by inhaled anesthetics in infant mice. Iron supplementation before anesthesia is an effective strategy to prevent cognitive impairment caused by Sev in infants.

Cerebellar Purkinje cell firing promotes conscious recovery from anesthesia state through coordinating neuronal communications with motor cortex.

Background: The neurobiological basis of gaining consciousness from unconscious state induced by anesthetics remains unknown. This study was designed to investigate the involvement of the cerebello-thalamus-motor cortical loop mediating consciousness transitions from the loss of consciousness (LOC) induced by an inhalational anesthetic sevoflurane in mice. Methods: The neural tracing and fMRI together with opto-chemogenetic manipulation were used to investigate the potential link among cerebello-thalamus-motor cortical brain regions. The fiber photometry of calcium and neurotransmitters, including glutamate (Glu), γ-aminobutyric acid (GABA) and norepinephrine (NE), were monitored from the motor cortex (M1) and the 5th lobule of the cerebellar vermis (5Cb) during unconsciousness induced by sevoflurane and gaining consciousness after sevoflurane exposure. Cerebellar Purkinje cells were optogenetically manipulated to investigate their influence on consciousness transitions during and after sevoflurane exposure. Results: Activation of 5Cb Purkinje cells increased the Ca2+ flux in the M1 CaMKIIα+ neurons, but this increment was significantly reduced by inactivation of posterior and parafascicular thalamic nucleus. The 5Cb and M1 exhibited concerted calcium flux, and glutamate and GABA release during transitions from wakefulness, loss of consciousness, burst suppression to conscious recovery. Ca2+ flux and Glu release in the M1, but not in the 5Cb, showed a strong synchronization with the EEG burst suppression, particularly, in the gamma-band range. In contrast, the Glu, GABA and NE release and Ca2+ oscillations were coherent with the EEG gamma band activity only in the 5Cb during the pre-recovery of consciousness period. The optogenetic activation of Purkinje cells during burst suppression significantly facilitated emergence from anesthesia while the optogenetic inhibition prolonged the time to gaining consciousness. Conclusions: Our data indicate that cerebellar neuronal communication integrated with motor cortex through thalamus promotes consciousness recovery from anesthesia which may likely serve as arousal regulation.

One node among many: sevoflurane-induced hypnosis and the challenge of an integrative network-level view of anaesthetic action.

Building on their known ability to influence sleep and arousal, Li and colleagues show that modulating the activity of glutamatergic pedunculopontine tegmental neurones also alters sevoflurane-induced hypnosis. This finding adds support for the shared sleep-anaesthesia circuit hypothesis. However, the expanding recognition of many neuronal clusters capable of modulating anaesthetic hypnosis raises the question of how disparate and anatomically distant sites ultimately interact to coordinate global changes in the state of the brain. Understanding how these individual sites work in concert to disrupt cognition and behaviour is the next challenge for anaesthetic mechanisms research.

Dopamine D1-receptor-expressing pathway from the nucleus accumbens to ventral pallidum-mediated sevoflurane anesthesia in mice.

BACKGROUND: General anesthesia has long been used in clinical practice, but its precise pharmacological effects on neural circuits are not fully understood. Recent investigations suggest that the sleep-wake system may play a role in the reversible loss of consciousness induced by general anesthetics. Studies in mice have shown that microinjection of dopamine receptor 1 (D1R) agonists into the nucleus accumbens (NAc) promotes recovery from isoflurane anesthesia, while microinjection of D1R antagonists has the opposite effect. Furthermore, during the induction and maintenance of sevoflurane anesthesia, there is a significant decrease in extracellular dopamine levels in the NAc, which subsequently increases during the recovery period. These findings suggest the involvement of the NAc in the regulation of general anesthesia. However, the specific role of D1R-expressing neurons in the NAc during general anesthesia and the downstream effect pathways are still not well understood. METHODS: In order to analyze the impact of sevoflurane anesthesia on NAcD1R neurons and the NAcD1R -VP pathway, this study employed calcium fiber photometry to investigate alterations in the fluorescence intensity of calcium signals in dopamine D1-receptor-expressing neurons located in the nucleus accumbens (NAcD1R neurons) and the NAcD1R -VP pathway during sevoflurane anesthesia. Subsequently, optogenetic techniques were utilized to activate or inhibit NAcD1R neurons and their synaptic terminals in the ventral pallidum (VP), aiming to elucidate the role of NAcD1R neurons and the NAcD1R -VP pathway in sevoflurane anesthesia. These experiments were supplemented with electroencephalogram (EEG) recordings and behavioral tests. Lastly, a genetically-encoded fluorescent sensor was employed to observe changes in extracellular GABA neurotransmitters in the VP during sevoflurane anesthesia. RESULTS: Our findings revealed that sevoflurane administration led to the inhibition of NAcD1R neuron population activity, as well as their connections within the ventral pallidum (VP). We also observed a reversible reduction in extracellular GABA levels in the VP during both the induction and emergence phases of sevoflurane anesthesia. Additionally, the optogenetic activation of NAcD1R neurons and their synaptic terminals in the VP resulted in a promotion of wakefulness during sevoflurane anesthesia, accompanied by a decrease in EEG slow wave activity and burst suppression rate. Conversely, the optogenetic inhibition of the NAcD1R -VP pathway exerted opposite effects. CONCLUSION: The NAcD1R -VP pathway serves as a crucial downstream pathway of NAcD1R neurons, playing a significant role in regulating arousal during sevoflurane anesthesia. Importantly, this pathway appears to be associated with the release of GABA neurotransmitters from VP cells.

Effects of Pharmacological Intervention on Recovery After Sevoflurane Anesthesia in Children: a Network Meta-analysis of Randomized Controlled Trials.

Sevoflurane, commonly administered to children as anesthesia, often leads to emergence delirium (ED). Currently, a consensus is lacking among clinicians regarding pharmacological interventions to improve recovery. To determine an effective approach, we compared the effects of several drugs in lowering the incidence of ED after sevoflurane anesthesia in children.We searched online databases for relevant randomized controlled trials (59 studies selected; 5199 NMA-eligible participants) and performed a frequentist network meta-analysis (NMA). This study was registered on PROSPERO (number CRD: 42022329939).All included studies had a low to moderate risk of overall bias. The incidence of ED after sevoflurane anesthesia in children differed according to other drugs administered, and were ranked from high to low according to the surface under the cumulative ranking curve (SUCRA).Sufentanil (91.2%) and dexmedetomidine (77.6%) were more likely to reduce the incidence (SUCRA value) of ED, whereas the placebo (6.5%), ramelteon (11.1%), and magnesium (18%) were less likely to reduce the incidence of ED. Remifentanil (89.3%) ranked first in shortening emergence time, followed by placebo (82.4%) and ketamine (69.7%). Placebo shortened extubation time, followed by remifentanil (66.5%) and alfentanil (61.4%).Sufentanil and remifentanil lowered sevoflurane-induced ED incidences among children and shortened the emergence time more effectively than other drugs. Most adjuvant drugs that are combined with sevoflurane either do not change or may even prolong extubation time. Further research and clinical trials are required to support and update these conclusions.

Malignant hyperthermia in maxillofacial surgery: Literature review supported by case presentation.

OBJECTIVE: Malignant hyperthermia (MH) is characterized by a state of hypermetabolism after exposure to halogenated inhalational anesthetics or succinylcholine. The aims of this study were to carry out an updated review on the subject and report an illustrative case of MH in urgent maxillofacial surgery. MATERIAL AND METHODS: A search of the PubMed/MEDLINE database using the keyword "malignant hyperthermia" was performed including articles published over the last 11 years in English, Spanish or Portuguese. Exclusion criteria were similar presentations but not associated with MH and cases not related to the use of anesthetic drugs as a trigger of the condition. CASE REPORT: A 45-year-old man (75 kg, ASA status IE) with a negative family history for neuromuscular diseases, victim of a car accident with a facial fracture, underwent surgery under balanced general anesthesia and developed signs of MH 4 h after anesthesia induction. In our patient, the causative agent was sevoflurane and the diagnosis of MH was confirmed, subsequently, by muscle biopsy. RESULTS/DISCUSSION: Overall, 44 cases of MH were found. According to the recent literature, MH shows a male predilection (3:1) and the mean age of patients is 32.2 ± 22.2 years. The most frequently cited causative agents were sevoflurane (30.5%), isoflurane (22.2%), and sevoflurane + succinylcholine (13.8%). The most common clinical indicators included hypercarbia (88.8%), hyperthermia (86.1%), and tachycardia (63.8%). Dantrolene was administered in 24 cases. The outcome was favorable in 31 cases (86.1%). The in vitro muscle contracture test (IVCT) was performed in only 15 patients and all of them tested positive. In our patient, the causative agent was sevoflurane and the diagnosis of MH was confirmed by muscle biopsy. CONCLUSION: The mortality from MH is still high and an early clinical diagnosis and specific treatment with dantrolene are necessary for a favorable outcome. A complete understanding will allow better management of patients with MH. At present, the best management is to identify susceptible patients and to avoid triggering agents, combined with vigilant monitoring.

Isovitexin restores sevoflurane­induced cognitive dysfunction by mediating autophagy through activation of the PGC­1α/FNDC5 signaling pathway.

Postoperative cognitive dysfunction is a severe neurological complication. How to improve the cognitive impairment caused by sevoflurane, a most common inhaled anesthetic, remains a question worthy of studying. Isovitexin (IVX) is a trihydroxyl flavonoid that is a naturally bioactive ingredient found in various medicinal plants and has antioxidant, anti­inflammatory and neuroprotective properties. The role of IVX in anesthetic­induced nerve injury is rarely reported and the mechanisms are unclear. In this study, we found that IVX improved the cognitive dysfunction induced by sevoflurane in rats. It inhibited sevoflurane­induced cell apoptosis. In addition, IVX increased sevoflurane­induced autophagy in rat brain. Mechanically, IVX activated the PGC­1α/FNDC5 pathway in rat brain, and depletion of FNDC5 could inhibit the neuroprotective function of IVX. In conclusion, our results suggested that IVX restored sevoflurane­induced cognitive dysfunction by mediating autophagy through the activation of the PGC­1α/FNDC5 pathway.

Does Resveratrol Prevent Sevoflurane Toxicity in Newborn Rats?

Inhalation anesthetics have been shown to cause neurodevelopmental disorders and neurotoxic effects. In this study, we aimed to investigate the effect of resveratrol on the possible neurotoxic effect of sevoflurane and the brain-derived neurotrophic factor (BDNF) pathway in newborn rats. The animals were divided into four groups: control, sevoflurane, sevoflurane+resveratrol 25 mg/kg, and sevoflurane+resveratrol 50 mg/kg. The groups that received anesthesia were given 3% sevoflurane for 2 h on the postnatal seventh, eighth, and ninth days. Control gas was applied to the control group. The Morris water maze (MWM) test was performed on postnatal 35th day. After performing the open field test on the postnatal 41st day, the animals were dissected, and the hippocampal BDNF levels were determined by Western blot method. In the MWM test, there was a significant decrease in the time spent in the target quadrant in the sevoflurane anesthesia group compared with control group. This reduction was reversed with the resveratrol pretreatment. Sevoflurane exposure significantly decreased hippocampal BDNF levels compared with the control group. The resveratrol 25 mg/kg pretreatment did not reverse this reduction, whereas resveratrol 50 mg/kg ameliorated this impairment. Sevoflurane did not cause any significant difference in the rats' performance in the open field test. However, 50 mg/kg resveratrol pretreatment caused a statistically significant increase in this performance. Our results showed that sevoflurane impaired learning and memory functions in newborn rats and resveratrol reversed this deterioration. Also BDNF might play a role in this beneficial effect of resveratrol.

Effects of transcutaneous electrical nerve stimulation on myocardial protection in patients undergoing aortic valve replacement: a randomized clinical trial.

BACKGROUND: Cardiopulmonary bypass-related myocardial ischemia-reperfusion injury is a major contributor to postoperative morbidity. Although transcutaneous electrical nerve stimulation (TENS) has been found to have cardioprotective effects in animal studies and healthy volunteers, its effects on cardiac surgery under cardiopulmonary bypass patients have not been evaluated. We investigated the effects of TENS on myocardial protection in patients undergoing aortic valve replacement surgery using cardiopulmonary bypass. METHODS: Thirty patients were randomized to receive TENS or sham in three different anesthetic states - pre-anesthesia, sevoflurane, or propofol (each n = 5). TENS was applied with a pulse width of 385 µs and a frequency of 10 Hz using two surface electrodes at the upper arm for 30 min. Sham treatment was provided without stimulation. The primary outcome was the difference in myocardial infarct size following ischemia-reperfusion injury in rat hearts perfused with pre- and post-TENS plasma dialysate obtained from the patients using Langendorff perfusion system. The cardioprotective effects of TENS were determined by assessing reduction in infarct size following treatment. RESULTS: There were no differences in myocardial infarct size between pre- and post-treatment in any group (41.4 ± 4.3% vs. 36.7 ± 5.3%, 39.8 ± 7.3% vs. 27.8 ± 12.0%, and 41.6 ± 2.2% vs. 37.8 ± 7.6%; p = 0.080, 0.152, and 0.353 in the pre-anesthesia, sevoflurane, and propofol groups, respectively). CONCLUSIONS: In our study, TENS did not show a cardioprotective effect in patients undergoing aortic valve replacement surgery. TRIAL REGISTRATION: This study was registered at clinicaltrials.gov ( NCT03859115 , on March 1, 2019).

A Neural Circuit from the Paraventricular Thalamus to the Bed Nucleus of the Stria Terminalis for the Regulation of States of Consciousness during Sevoflurane Anesthesia in Mice.

BACKGROUND: The neural circuitry underlying sevoflurane-induced modulation of consciousness is poorly understood. This study hypothesized that the paraventricular thalamus bed nucleus of the stria terminalis pathway plays an important role in regulating states of consciousness during sevoflurane anesthesia. METHODS: Rabies virus-based transsynaptic tracing techniques were employed to reveal the neural pathway from the paraventricular thalamus to the bed nucleus of the stria terminalis. This study investigated the role of this pathway in sevoflurane anesthesia induction, maintenance, and emergence using chemogenetic and optogenetic methods combined with cortical electroencephalogram recordings. Both male and female mice were used in this study. RESULTS: Both γ-aminobutyric acid-mediated and glutamatergic neurons in the bed nucleus of the stria terminalis receive paraventricular thalamus glutamatergic projections. Chemogenetic inhibition of paraventricular thalamus glutamatergic neurons prolonged the sevoflurane anesthesia emergence time (mean ± SD, hM4D-clozapine N-oxide vs. mCherry-clozapine N-oxide, 281 ± 88 vs. 172 ± 48 s, P < 0.001, n = 24) and decreased the induction time (101 ± 32 vs. 136 ± 34 s, P = 0.002, n = 24), as well as the EC5 0 for the loss or recovery of the righting reflex under sevoflurane anesthesia (mean [95% CI] for the concentration at which 50% of the mice lost their righting reflex, 1.16 [1.12 to 1.20] vs. 1.49 [1.46 to 1.53] vol%, P < 0.001, n = 20; and for the concentration at which 50% of the mice recovered their righting reflex, 0.95 [0.86 to 1.03] vs. 1.34 [1.29 to 1.40] vol%, P < 0.001, n = 20). Similar results were observed during suppression of the paraventricular thalamus bed nucleus-stria terminalis pathway. Optogenetic activation of this pathway produced the opposite effects. Additionally, transient stimulation of this pathway efficiently induced behavioral arousal during continuous steady-state general anesthesia with sevoflurane and reduced the depth of anesthesia during sevoflurane-induced burst suppression. CONCLUSIONS: In mice, axonal projections from the paraventricular thalamic neurons to the bed nucleus of the stria terminalis contribute to regulating states of consciousness during sevoflurane anesthesia.

Adequacy of maternal anesthesia depth with two sodium thiopental doses in elective caesarean section: a randomized clinical trial.

BACKGROUND: Administration of an optimal dose of anesthetic agent to ensure adequate depth of hypnosis with the lowest risk of adverse effects to the fetus is highly important in cesarean section. Sodium thiopental (STP) is still the first choice for induction of anesthesia in some countries for this obstetric surgery. We aimed to compare two doses of STP with regarding the depth of anesthesia and the condition of newborn infants. METHODS: In this clinical trial, parturient undergoing elective Caesarian section were randomized into two groups receiving either low-dose (5 mg/kg) or high-dose (7 mg/kg) STP. Muscle relaxation was provided with succinylcholine 2 mg/kg and anesthesia was maintained with O2/N2O and sevoflurane. The depth of anesthesia was evaluated using isolated forearm technique (IFT) and bispectral index (BIS) in various phases. Additionally, infants were assessed using Apgar score and neurobehavioral test. RESULTS: Forty parturient were evaluated in each group. BIS was significantly lower in high-dose group at skin incision to delivery and subcutaneous and skin closure. Also, significant differences were noticed in IFT over induction to incision and incision to delivery. Apgar score was significantly lower in high-dose group at 1 min after delivery. Newborn infants in low-dose group had significantly better outcomes in all three domains of the neurobehavioral test. CONCLUSION: 7 mg/kg STP is superior to 5 mg/kg in creating deeper hypnosis for mothers. However, it negatively impacts Apgar score and neurobehavioral test of neonates. STP seems to has dropped behind as an acceptable anesthetic in Cesarean section. TRIAL REGISTRATION: IRCT No: 2016082819470 N45 , 13/03/2019.

Different roles of T-type calcium channel isoforms in hypnosis induced by an endogenous neurosteroid epipregnanolone.

BACKGROUND: Many neuroactive steroids induce sedation/hypnosis by potentiating γ-aminobutyric acid (GABAA) currents. However, we previously demonstrated that an endogenous neuroactive steroid epipregnanolone [(3ß,5ß)-3-hydroxypregnan-20-one] (EpiP) exerts potent peripheral analgesia and blocks T-type calcium currents while sparing GABAA currents in rat sensory neurons. This study seeks to investigate the behavioral effects elicited by systemic administration of EpiP and to characterize its use as an adjuvant agent to commonly used general anesthetics (GAs). METHODS: Here, we utilized electroencephalographic (EEG) recordings to characterize thalamocortical oscillations, as well as behavioral assessment and mouse genetics with wild-type (WT) and different knockout (KO) models of T-channel isoforms to investigate potential sedative/hypnotic and immobilizing properties of EpiP. RESULTS: Consistent with increased oscillations in slower EEG frequencies, EpiP induced an hypnotic state in WT mice when injected alone intra-peritoneally (i.p.) and effectively facilitated anesthetic effects of isoflurane (ISO) and sevoflurane (SEVO). The CaV3.1 (Cacna1g) KO mice demonstrated decreased sensitivity to EpiP-induced hypnosis when compared to WT mice, whereas no significant difference was noted between CaV3.2 (Cacna1h), CaV3.3 (Cacna1i) and WT mice. Finally, when compared to WT mice, onset of EpiP-induced hypnosis was delayed in CaV3.2 KO mice but not in CaV3.1 and CaV3.3 KO mice. CONCLUSION: We posit that EpiP may have an important role as novel hypnotic and/or adjuvant to volatile anesthetic agents. We speculate that distinct hypnotic effects of EpiP across all three T-channel isoforms is due to their differential expression in thalamocortical circuitry.

Inhibitive Effect of Luteolin on Sevoflurane-Induced Neurotoxicity through Activation of the Autophagy Pathway by HMOX1.

Luteolin is a flavone compound occurring in a variety of medicinal plants, which is reported to have neuroprotective properties. In this study, we aimed to explore the effects of luteolin in alleviating sevoflurane-induced neurotoxicity. GeneCards and Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform were employed to screen luteolin, sevoflurane, and neurotoxicity-related genes. Subsequently, we isolated primary neurons from the hippocampus of 1-day-old C57BL/6J mice and tested for cytotoxicity after treatment of different concentrations of luteolin. Next, we measured the expression of apoptosis by flow cytometry and assessed inflammation-related factors, including heme oxygenase-1 expression detected by immunohistochemical staining and neuronal apoptosis. Finally, water maze, open field, and fear conditioning tests were conducted to observe the interaction between luteolin and sevoflurane in cognitive impairment of mice. Luteolin had the lowest cytotoxicity at concentrations of 30 or 60 µg/mL; we selected 30 µg/mL for drug administration experiments in vitro. Luteolin inhibited sevoflurane-induced neuronal apoptosis and inflammatory responses through the autophagic pathway and thus ameliorated sevoflurane-induced cognitive impairment in mice. Mechanistically, luteolin up-regulated heme oxygenase-1 expression, which activated the autophagy pathway in vitro. This was confirmed by subsequent histological experiments in mice and behavioral results showing rescue cognitive impairment. Our findings uncovered an inhibitory role of luteolin in sevoflurane-induced neuronal apoptosis and inflammatory response through activation of autophagy arising from up-regulation of heme oxygenase-1, thereby alleviating sevoflurane-induced cognitive impairment in mice.

Analgesic effectiveness and improvement in quality of life after using topical sevoflurane for an extremely painful anal fissure / Eficácia analgésica e melhoria da qualidade de vida com o uso tópico de sevoflurano em fissura anal extremamente dolorosa

Painful anal fissures could be distressing conditions that severely impair the patients' quality of life. The analgesic effectiveness of topical drugs, such as calcium-antagonists and nitrates is quite variable. The inhalational anesthetic sevoflurane is being repurposed as a topical analgesic for painful chronic wounds.We report a pioneer experience treating a painful chronic anal fissure with topical sevoflurane. A young adult male was suffering from an extremely painful chronic anal fissure, which severely affected his quality of life. The topical treatment with nitroglycerine and diltiazem gels failed. The patient agreed to the treatement with topical sevoflurane as an off-label medication, and it produced an immediate, intense, and long-lasting analgesic effect. An intense but rapidly transient burning sensation, as well as persistent but well-tolerated flatulence were the only adverse effects. The quality of life was greatly improved, and the cost of the treatment was affordable. Therefore, the off-label use of topical sevoflurane appears to be an effective alternative for the symptomatic treatment of painful anal fissures (AU)

As fissuras anais dolorosas podem ser condições angustiantes que prejudicam gravemente a qualidade de vida dos pacientes. A eficácia analgésica de medicamentos tópicos, como antagonistas de cálcio e nitratos, é bastante variável. O anestésico inalatório sevoflurano está sendo reaproveitado como analgésico tópico para feridas crônicas dolorosas. Relatamos uma experiência pioneira de tratamento com sevoflurano tópico em fissura anal crônica dolorosa. Umjovemadulto do sexomasculino sofria de uma fissura anal crônica extremamente dolorosa, que afetava gravemente sua qualidade de vida. O tratamento tópico com nitroglicerina e géis de diltiazem foi ineficaz. O paciente concordou com o tratamento com sevoflurano tópico como medicamento off-label, ou seja, com uso diferente do aprovado embula. O sevoflurano tópico produziu um efeito analgésico imediato, intenso e duradouro. Uma sensação de ardência intensa, mas transitória, e flatulência persistente, embora bem tolerada, foram os únicos efeitos adversos. A qualidade de vidamelhorou significativamente, e o custo do tratamento revelou-se acessível. Portanto, o uso off-label de sevoflurano tópico pode ser uma alternativa analgésica eficaz em casos de fissuras anais dolorosas. (AU)

Sevoflurane Suppresses the Migration, Invasion, and Epithelial-Mesenchymal Transition of Breast Cancer Cells Through the miR-139-5p/ARF6 Axis.

BACKGROUND: Breast cancer (BC) is common cancer in female globally. Sevoflurane (SEV) has been reported to inhibit the metastasis of multiple cancers, including glioma, colorectal cancer, and hepatocellular carcinoma. However, the role of SEV in the metastasis of BC cells remains poorly understood. METHODS: Transwell migration and invasion assays were performed to detect the migration and invasion of BC cells. Western blot assay was carried out to measure epithelial-mesenchymal transition (EMT)-related proteins in BC cells, including E-cadherin, N-cadherin, and fibronectin. Quantitative real-time polymerase chain reaction was conducted to determine the enrichment of miR-139-5p and ADP-ribosylation factor 6 (ARF6) in BC tissues and cells. The protein expression of ARF6 in BC tissues and cells was measured by western blot assay. The target of miR-139-5p was predicted by starBase software, and the target relationship between miR-139-5p and ARF6 in BC cells was confirmed by dual-luciferase reporter assay. RESULTS: SEV suppressed the migration, invasion, and EMT of BC cells, especially in the high-concentration SEV group. The level of miR-139-5p was lower in BC tissues and cells than that in paired normal tissues and normal mammary epithelial cells MCF-10A. MiR-139-5p was upregulated in BC cells treated with SEV. ARF6 was upregulated in BC tissues and cells compared with that in corresponding normal tissues and normal mammary epithelial cells MCF-10A. SEV reduced the mRNA and protein expression of ARF6 in BC cells. The accumulation of ARF6 or the interference of miR-139-5p reversed the suppressive effects of SEV treatment on the migration, invasion, and EMT of BC cells. MiR-139-5p bound to ARF6 and inversely modulated the level of ARF6 in BC cells. The transfection of si-ARF6 attenuated the promoting effects of miR-139-5p depletion on the migration, invasion, and EMT of BC cells treated with SEV. CONCLUSIONS: SEV suppressed the migration, invasion, and EMT of BC cells through downregulating the abundance of ARF6 by upregulating miR-139-5p. The miR-139-5p/ARF6 axis might be a promising target for the treatment of BC.

Experimental evidence refuting the assumption of phosphorus-31 nuclear-spin entanglement-mediated consciousness.

Phosphorus-31 nuclear-spin entanglements within Ca9(PO4)6 molecules (Posner molecules) have been proposed to be central for neural processing. However, this has yet to be proven experimentally. Relatedly, increasing calcium ion concentration in the cerebrospinal fluid has been proposed to enhance consciousness by accelerating Posner molecules' creation. A dependence on calcium isotope is also expected. Here we test these predictions experimentally by measuring the loss of righting reflex ED50 for mice to sevoflurane - an increase in loss of righting reflex ED50 indicates a higher level of consciousness and vice versa. Our mice's findings demonstrate that intracerebroventricular injection of EGTA enhances the sevoflurane-induced loss of righting reflex ED50 while injecting calcium-40 chloride or calcium-43 chloride causes an opposite effect. Further, the identical effects of calcium-40 and calcium-43 indicate an absence of calcium isotope dependence. Here, our findings disprove conventional proposals that calcium ion concentration correlates with consciousness.

Association between well-characterized gene polymorphisms and the hypnosis response caused by sevoflurane-induced anaesthesia.

WHAT IS KNOWN AND OBJECTIVE: Sevoflurane is the most widely used volatile anaesthetic in clinical practice. It exhibits a hypnotic (unconsciousness) effect and causes a loss of reaction to noxious stimuli (immobility). However, to date, the mechanism of action of sevoflurane is poorly understood. In this study, we explored the effects of genetic variations on sevoflurane-induced hypnosis. METHODS: Sixty-six SNPs in 18 candidate genes were genotyped using MALDI-TOF MassARRAY in a discovery cohort containing 161 patients administered sevoflurane. Significant polymorphisms were assessed in a validation cohort containing 265 patients. RESULTS AND DISCUSSION: Three polymorphisms (GRIN1 rs28681971, rs79901440 and CHRNA7 rs72713539) were significantly associated with the time to loss of consciousness in patients treated with sevoflurane in the discovery cohort; among them, GRIN1 rs28681971 showed a significant association even after false discovery rate (FDR) correction (pFDR  = 0.039). Following the validation analysis, GRIN1 rs28681971 and rs79901440 showed statistical efficacy (pFDR  = 0.027, 0.034). Combined assessments and meta-analysis of the results of the two cohorts indicated that the C carriers of rs28681971 and T carriers of rs79901440 in GRIN1 require a longer time to achieve unconsciousness. WHAT IS NEW AND CONCLUSION: These findings suggest that GRIN1 polymorphisms are associated with sevoflurane-induced unconsciousness. Thus, the genotypes of GRIN1 may serve as novel and meaningful biomarkers for sevoflurane-induced unconsciousness.

Monochromatic Blue Light Activates Suprachiasmatic Nucleus Neuronal Activity and Promotes Arousal in Mice Under Sevoflurane Anesthesia.

Background: Monochromatic blue light (MBL), with a wavelength between 400-490 nm, can regulate non-image-forming (NIF) functions of light in the central nervous system. The suprachiasmatic nucleus (SCN) in the brain is involved in the arousal-promoting response to blue light in mice. Animal and human studies showed that the responsiveness of the brain to visual stimuli is partly preserved under general anesthesia. Therefore, this study aimed to investigate whether MBL promotes arousal from sevoflurane anesthesia via activation of the SCN in mice. Methods: The induction and emergence time of sevoflurane anesthesia under MBL (460 nm and 800 lux) exposure was measured. Cortical electroencephalograms (EEGs) were recorded and the burst-suppression ratio (BSR) was calculated under MBL during sevoflurane anesthesia. The EEGs and local field potential (LFP) recordings with or without locally electrolytic ablated bilateral SCN were used to further explore the role of SCN in the arousal-promoting effect of MBL under sevoflurane anesthesia. Immunofluorescent staining of c-Fos was conducted to reveal the possible downstream mechanism of SCN activation. Results: Unlike the lack of effect on the induction time, MBL shortened the emergence time and the EEG recordings showed cortical arousal during the recovery period. MBL resulted in a significant decrease in BSR and a marked increase in EEG power at all frequency bands except for the spindle band during 2.5% sevoflurane anesthesia. MBL exposure under sevoflurane anesthesia enhances the neuronal activity of the SCN. These responses to MBL were abolished in SCN lesioned (SCNx) mice. MBL evoked a high level of c-Fos expression in the prefrontal cortex (PFC) and lateral hypothalamus (LH) compared to polychromatic white light (PWL) under sevoflurane anesthesia, while it exerted no effect on c-Fos expression in the ventrolateral preoptic area (VLPO) and locus coeruleus (LC) c-Fos expression. Conclusions: MBL promotes behavioral and electroencephalographic arousal from sevoflurane anesthesia via the activation of the SCN and its associated downstream wake-related nuclei. The clinical implications of this study warrant further study.

Syringe or mask? Loop electrosurgical excision procedure under local or general anesthesia: a randomized trial.

BACKGROUND: Loop electrosurgical excision procedure may be performed under local anesthesia or general anesthesia, and practice patterns differ worldwide. No randomized head-to-head comparison has been published to confirm or refute either practice. OBJECTIVE: This study aimed to compare loop electrosurgical excision procedure under local anesthesia vs general anesthesia regarding patient satisfaction and procedure-related outcomes such as rates of involved margins, complications, pain, and blood loss. STUDY DESIGN: Consecutive women referred to our colposcopy unit were recruited. Loop electrosurgical excision procedure was performed under local anesthesia with 4 intracervical injections of bupivacaine hydrochloride 0.5% or under general anesthesia with fentanyl, propofol, and a laryngeal mask with sevoflurane maintenance. The primary endpoint was patient satisfaction assessed on the day of surgery and 14 days thereafter using a Likert scale (score 0-100) and a questionnaire. Secondary endpoints included rates of involved margins, procedure-related complications, pain, blood loss, and surgeon preference. Results were compared using nonparametric and chi-square tests. RESULTS: Between July 2018 and February 2020, we randomized 208 women, 108 in the local anesthesia arm and 100 in the general anesthesia arm. In the intention-to-treat analysis, patient satisfaction did not differ between the study groups directly after surgery (Likert scale 100 [90-100] vs 100 [90-100]; P=.077) and 14 days thereafter (Likert scale 100 [80-100] vs 100 [90-100]; P=.079). In the per-protocol analysis, women in the local anesthesia arm had significantly smaller cone volumes (1.11 cm3 [0.70-1.83] vs 1.58 cm3 [1.08-2.69], respectively; P<.001), less intraoperative blood loss (Δhemoglobin, 0.2 g/dL [-0.1 to 0.4] vs 0.5 g/dL [0.2-0.9]; P<.001), and higher satisfaction after 14 days (100 [90-100] vs 100 [80-100]; P=.026), whereas surgeon preference favored general anesthesia (90 [79-100] vs 100 [90-100], respectively; P=.001). All other secondary outcomes did not differ between groups (resection margin status R1, 6.6% vs 2.1% [P=.26]; cone fragmentation, 12.1% vs 6.3% [P=.27]; procedure duration, 151.5 seconds [120-219.5] vs 180 seconds [117-241.5] [P=.34]; time to complete hemostasis, 60 seconds [34-97] vs 70 seconds [48.25-122.25] [P=.08]; complication rate, 3.3% vs 1.1% [P=.59]). In a multivariate analysis, parity (P=.03), type of transformation zone (P=.03), and cone volume (P=.02) and not study group assignment, age, body mass index, and degree of dysplasia independently influenced the primary endpoint. CONCLUSION: Loop electrosurgical excision procedure under local anesthesia is equally well tolerated and offers patient-reported and procedure-related benefits over general anesthesia, supporting the preferred practice in some institutions and refuting the preferred practice in others.