Efecto neuroprotector del sevoflurano en anestesia general

Influence of Sevoflurane Postconditioning on Hypoxic-Ischemic Brain Injury via Nrf2-Regulated Ferroptosis in Neonatal Rats

BACKGROUND

The mechanisms by which sevoflurane protects the brain from hypoxic-ischemic brain injury (HIBI) are unknown. Ferroptosis occurs during HIBI and is regulated by the nuclear factor erythroid 2-related factor 2 (Nrf2). This study investigated the roles of Nrf2-regulated ferroptosis in sevoflurane postconditioning (SPC)-mediated neuroprotection during HIBI.

METHODS

HIBI was induced in 7-day-old rats. SPC (2.5%, 30 minutes) was performed immediately after HIBI, and some rats were injected with ML385 (an Nrf2-inhibitor) 30 minutes before HIBI. Ferroptosis was evaluated by measuring glutathione peroxidase 4 (GPx4), solute carrier family 7 member 11 (SLC7A11, also known as xCT), glutathione (GSH), cysteine, iron, malondialdehyde (MDA) levels, and mitochondrial morphology. Nrf2 and heme oxygenase-1 (HO-1) expression were determined to explore the signaling pathways involved in SPC-mediated neuroprotection. Brain morphology, left/right hemisphere weight ratios, and Nissl staining were measured to assess brain damage. The Morris water maze was conducted to assess long-term learning and memory abilities.

RESULTS

SPC alleviated HIBI-induced cysteine depletion-induced (HIBI versus SPC, xCT/β-tubulin ratio: -0.435 [95% CI, -0.727 to -0.143], P = .003; Cysteine (% of Sham): -29.8 [95% CI, -39.4 to -20.2], P < .001; GSH (% of Sham): -46.5 [95% CI, -54.6 to -38.4], P < .001) and GPx4 inhibition-induced ferroptosis (HIBI versus SPC, GPx4/β-tubulin ratio: -0.287 [95% CI, -0.514 to -0.0603], P = .01). Compared with the HIBI group, the SPC group showed improved learning and memory abilities (HIBI versus SPC, platform crossings: -4 times [95% CI, -7 to -1], P = .002; escape latency: 46 seconds [95% CI, 24 to 68], P < .001), reduced brain damage (HIBI versus SPC, weight ratio of left/right cerebral hemispheres: -13.1 [95% CI, -15.7 to -10.4], P < .001; neuronal density ratio: -0.450 [-0.620 to -0.280], P < .001), and increased Nrf2 and HO-1 protein levels (HIBI versus SPC, Nrf2/β-tubulin ratio: -1.89 [95% CI, -2.82 to -0.970], P < .001; HO-1/β-tubulin ratio: -1.08 [95% CI, -1.73 to -0.442], P < .001). Inhibiting Nrf2 via ML385 partly reversed SPC-mediated neuroprotection (SPC versus SPC+ML385, weight ratio of left/right cerebral hemispheres: 12.4 [95% CI, 9.73-15.1], P < .001; neuronal density ratio: 0.412 [95% CI, 0.242-0.582], P < .001), accompanied by decreased HO-1 expression (SPC versus SPC+ML385, HO-1/β-tubulin ratio: 1.70 [95% CI, 1.05-2.34], P < .001).

CONCLUSIONS

SPC inhibits both cysteine depletion- and GPx4 inhibition-induced ferroptosis by regulating Nrf2/HO-1 signaling to protect against HIBI.

Beyond surgery: Repurposing anesthetics for treatment of central nervous system disorders

The development of new drugs is a complex, expensive, and time-consuming process, often fraught with a high likelihood of failure. Amid these obstacles, drug repurposing, which identifies new therapeutic applications for already existing medications, offers a more economical and time-saving approach, particularly in the challenging field of neurological and psychiatric disorders. This narrative review explores both preclinical and clinical studies to examine the potential of anesthetics such as ketamine, nitrous oxide, isoflurane, sevoflurane, propofol, dexmedetomidine, and sodium oxybate in treating central nervous system disorders. Various research highlights the potential of anesthetics to provide rapid antidepressant effects, enhance learning and memory, improve synaptic plasticity, and offer neuroprotective benefits, demonstrating promise for treating depression, post-traumatic stress disorder, cognitive decline, traumatic brain injury, and neurodegenerative disorders. Anesthetics appear to alleviate symptoms in neurological conditions, likely by modulating GABAergic and glutamatergic pathways. However, challenges such as dose-dependent neurotoxicity, variability in preclinical and clinical outcomes, as well as environmental concerns remain significant issues. Future research is essential to optimize dosing strategies, ensure long-term safety, and gain a deeper understanding of the precise mechanisms of action. The concept of anesthetics' repurposing presents a unique solution to tackle the challenges in neurological and psychiatric therapy by providing a platform for the development of new and improved therapies.

Evaluation of the neuroprotective effect of antipsychotics by serum quantification of protein S100B

OBJECTIVE

This research delves into the intricate interplay between antipsychotic medications and neuroprotection focusing on the S100B protein, a central player in the regulation of neuroapoptotic activity.

METHOD

Blood samples were collected to assess serum S100B protein levels using an immunoassay of immunoelectrochemiluminescence. The first two samples were collected with a 3-month interval between each, and the third sample was obtained 6 months after the previous one. Changes in S100B protein levels throughout the study were assessed using Friedman's ANOVA test. This was followed by the Wilcoxon signed-rank test with Bonferroni correction to account for multiple comparisons.

RESULTS

This study involved 40 patients diagnosed with severe mental disorders (34 schizophrenia, 4 schizoaffective disorder, one bipolar disorder, and one borderline personality disorder). These patients had been receiving antipsychotic treatment for an average duration of 17 years. The results revealed that the S100B protein remained within physiological levels (median values 39.0 ng/L for the first sample, median values 41.0 ng/L for the second sample, and median values 40.5 ng/L for the third sample) with no significant changes (p = 0.287), with all anti-psychotic medicaments values consistently below 50 ng/L, a lower value compared to maximum range of 105 ng/L. Importantly, there were no significant differences in S100B protein levels between patients on monotherapy and those on combination antipsychotic therapy (p = 0.873), suggesting that combination therapy did not increase neuroapoptotic activity.

CONCLUSIONS

These findings provide compelling evidence for the potential neuroprotective effects of long-term antipsychotic treatment in individuals with severe mental disorders. By maintaining physiological levels of the S100B protein, antipsychotic medications may help protect against neuronal damage and dysfunction. This research contributes valuable insights into the neuroprotective mechanisms of antipsychotic drugs, enhancing our understanding of their potential benefits in the treatment of severe mental disorders.

Evaluation of the neuroprotective effect of antipsychotics by serum quantification of protein S100B

OBJECTIVE

This research delves into the intricate interplay between antipsychotic medications and neuroprotection focusing on the S100B protein-a central player in the regulation of neuroapoptotic activity.

METHOD

Blood samples were collected to assess serum S100B protein levels using an immunoassay of immunoelectrochemiluminescence. The first two samples were collected with a 3-month interval between each, and the third sample was obtained 6 months after the previous one. Changes in S100B protein levels throughout the study were assessed using Friedman's ANOVA test. This was followed by the Wilcoxon signed-rank test with Bonferroni correction to account for multiple comparisons.

RESULTS

This study involved 40 patients diagnosed with severe mental disorders (34 schizophrenia, 4 schizoaffective disorder, 1 bipolar disorder, and 1 borderline personality disorder). These patients had been receiving antipsychotic treatment for an average duration of 17 years. The results revealed that the S100B protein remained within physiological levels (median values 39.0 ng/L for the first sample, median values 41.0 ng/L for the second sample, and median values 40.5 ng/L for the third sample) with no significant changes (p = 0.287), with all anti-psychotic medicaments values consistently below 50 ng/L, a lower value compared to maximum range of 105 ng/L. Importantly, there were no significant differences in S100B protein levels between patients on monotherapy and those on combination antipsychotic therapy (p = 0.873), suggesting that combination therapy did not increase neuroapoptotic activity.

CONCLUSIONS

These findings provide compelling evidence for the potential neuroprotective effects of long-term antipsychotic treatment in individuals with severe mental disorders. By maintaining physiological levels of the S100B protein, antipsychotic medications may help protect against neuronal damage and dysfunction. This research contributes valuable insights into the neuroprotective mechanisms of antipsychotic drugs, enhancing our understanding of their potential benefits in the treatment of severe mental disorders.

Inhalation Anesthetics Play a Janus-Faced Role in Self-Renewal and Differentiation of Stem Cells

Inhalation anesthesia stands as a pivotal modality within clinical anesthesia practices. Beyond its primary anesthetic effects, inhaled anesthetics have non-anesthetic effects, exerting bidirectional influences on the physiological state of the body and disease progression. These effects encompass impaired cognitive function, inhibition of embryonic development, influence on tumor progression, and so forth. For many years, inhaled anesthetics were viewed as inhibitors of stem cell fate regulation. However, there is now a growing appreciation that inhaled anesthetics promote stem cell biological functions and thus are now regarded as a double-edged sword affecting stem cell fate. In this review, the effects of inhaled anesthetics on self-renewal and differentiation of neural stem cells (NSCs), embryonic stem cells (ESCs), and cancer stem cells (CSCs) were summarized. The mechanisms of inhaled anesthetics involving cell cycle, metabolism, stemness, and niche of stem cells were also discussed. A comprehensive understanding of these effects will enhance our comprehension of how inhaled anesthetics impact the human body, thus promising breakthroughs in the development of novel strategies for innovative stem cell therapy approaches.

Reflection efficiencies of AnaConDa-S and AnaConDa-100 for isoflurane under dry laboratory and simulated clinical conditions: a bench study using a test lung

Background: Adequate sedation is important for the treatment of ICU patients. AnaConDa (Anesthetic-Conserving-Device; ACD; Sedana Medical, Sweden), connected between ventilator and the patient, retains isoflurane during expiration, and releases it back during inspiration. The reflection efficiency (Ref_Eff) corresponds to the percentage of expired anesthetic molecules that are re-inspired. We compared Ref_Eff of AnaConDa-S (ACD-50) and AnaConDa-100 (ACD-100) under laboratory (DRY) and simulated clinical conditions (CLIN) using a test lung.Methods: Measurements were made under DRY and CLIN, with different tidal volumes (TV: 300 mL & 500 mL) and infusion rates (0.5-10 mL·h^-1). Ref_Eff was calculated from the isoflurane concentration in the test-lung (C_ISO) and plotted against the anesthetic vapor volume exhaled in one breath (V-exh = C_ISO·TV).Results: DRY: Ref_Eff of both devices was ≈90% over a wide range of V-exh, but decreased when V-exh exceeded 5-7 mL (ACD-50) or 10-15 mL (ACD-100).CLIN: Ref_Eff of ACD-50 was 70-80% (ACD-100: 80-90%), decreasing gradually with increasing V-exh. For 1 Vol.% isoflurane at TV500, the infusion rate with ACD-50 was twofold higher compared to ACD-100 (4 versus 2 mL·h^-1).Conclusion: Under DRY and concentrations <1.5 Vol.%, Ref_Eff of both devices is around 90%. Under CLIN, ACD-100 performs better with Ref_Eff between 80% and 90% (ACD-50:70-80%), decreasing with increased vapor volume exhaled in one breath.

Prenatal sevoflurane exposure: Effects of iron metabolic dysfunction on offspring cognition and potential mechanism

For decades, the neurotoxicity caused by anesthetics in mammalian brain development has gained increasing attention. Exposure to anesthetics leads to neurotoxicity and apoptosis of nerve cells, which in turn induces cognitive dysfunction. Although most of the data came from animal studies, general anesthetics have been shown to have adverse effects on cognitive function in infants and young children in recent years. This concern has led to a number of retrospective studies that observed an association between general anesthesia in pregnant women and neurobehavioral problems in fetuses or offspring. Every year, many pregnant women undergo non-obstetric anesthesia due to various reasons such as traffic accidents, fetal interventions, acute appendicitis, symptomatic cholelithiasis, and trauma. A matter of concern for these pregnant women is whether anesthesia has a detrimental effect on fetal brain development in the womb and whether the fetus has cognitive impairment after birth. In humans, the association of anesthetic exposure in infants with the long-term impairment of neurologic functions has been reported in several retrospective clinical studies. Recently, we have found that sevoflurane anesthesia during pregnancy in mice-induced cognitive impairment in the offspring by causing iron deficiency and inhibiting myelinogenesis. Sevoflurane is a commonly used general anesthetic in the hospitals, which can induce neurotoxicity and cause cognitive impairment in fetuses, infants, children, and adults. However, the exact mechanism of sevoflurane-induced damage to the central nervous system (CNS) is not fully understood. Based on our recent results, this paper reviewed the effects of sevoflurane on cognitive impairment and pathological changes such as neurogenesis, neuronal apoptosis, and iron metabolism dysfunction in the offspring.

Dexmedetomidine alleviates sevoflurane-induced neurotoxicity via mitophagy signaling

Dexmedetomidine, a class of α2-adrenergic agonist, was reported to exert a neuroprotective effect on sevoflurane-induced neurotoxicity. However, the specific mechanisms have not been fully clarified yet. The aim of our study is to uncover the role of dexmedetomidine in sevoflurane-induced neurotoxicity. The rats pretreated with dexmedetomidine and/or Rapamycin 3-Methyladenine were housed in a box containing 30% O₂, 68% N₂ and 2% sevoflurane for 4 h for anesthesia. 24 h after drug injection, Morris water maze test was used to evaluate rats' learning and memory ability. Hematoxylin & eosin (H&E) staining was adopted to analyze the pathological changes of hippocampus. TUNEL assay was performed to measure cell apoptosis in hippocampus. Immunofluorescent assay was utilized to detect HSP60 level. The protein levels of LC3I, LC3II, Beclin-1, CypD, VDAC1 and Tom20 were examined by western blot. 5 weeks after drug injection, Morris water maze test was used to evaluate rats' learning and memory ability again. Dexmedetomidine alleviated sevoflurane-induced nerve injury and the impairment of learning and memory abilities. Additionally, dexmedetomidine inhibited sevoflurane-induced cell apoptosis in hippocampus. In mechanism, dexmedetomidine activated mitophagy to mitigate neurotoxicity by enhancing LC3II/LC3I ratio, HSP60, Beclin-1, CypD, VDAC1 and Tom20 protein levels in hippocampus. Dexmedetomidine alleviates sevoflurane-induced neurotoxicity via mitophagy signaling, offering a potential strategy for sevoflurane-induced neurotoxicity treatment.

Impact of Sevoflurane Versus Propofol Anesthesia on Post-Operative Cognitive Dysfunction in Elderly Cancer Patients: A Double-Blinded Randomized Controlled Trial

Background

Research on the clinical outcomes of surgical patients anaesthetized with sevoflurane and the association of sevoflurane with post-operative cognitive dysfunction (POCD) is scarce. We evaluated whether sevoflurane-based anesthesia increased the incidence of POCD and worsened prognosis compared to propofol-based anesthesia in elderly cancer patients.

Material/Methods

This single-center, prospective, double-blind randomized controlled trial included 234 patients aged 65 to 86 years undergoing tumor resection who received sevoflurane-based (Group S) or propofol-based (Group P) anesthesia during surgery. A series of neuropsychological tests was performed to evaluate cognitive function before surgery and at 7 days and 3 months post-operation, and the results were compared to those of healthy controls.

Results

At 7 days post-operation there were no significant differences in the incidence of POCD between patients who received sevoflurane-based or propofol-based anesthesia during surgery: Group S was at 29.1% (32 out of 110 patients) versus Group P at 27.3% (30 out of 110), P=0.764. At 3 months, Group S was at 11.3% (12 out of 106 patients) versus Group P at 9.2% (10 out of 109), P=0.604. During the first 2 days post-operation, the QoR-40 global score was significantly lower in Group S compared to Group P [POD 1: P=0.004; POD 2: P=0.001]. There were no significant differences in in-hospital post-operative complications, post-operative length of hospital stay, all-cause mortality at 30 days, and 3 months post-operation, or post-operative quality of life at 3 months between patients in Group S and Group P.

Conclusions

Sevoflurane-based anesthesia did not increase the incidence of POCD compared to propofol-based anesthesia at 7 days or 3 months post-operation or impact short-term post-operative prognosis.

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

Normal brain development in young children depends on a balance between excitation and inhibition of neurons, and alterations to this balance may cause apoptosis. During the perioperative period, both surgical stimuli and anesthetics can induce neurotoxicity. This article attempts to expand the perspective of a topical issue-anesthetic-induced neurotoxicity-by also considering the protective effect of general anesthetics against surgery-induced neurotoxicity, all of which may generate some controversy in the current literature. The "new" major factor influencing neurotoxicity-nociceptive stimulus-is discussed together with other factors to develop clinical and research strategies to obtain a balance between neurotoxicity and neuroprotection.

Medical gases for stroke therapy: summary of progress 2015-2016

Stroke is a cerebrovascular disease with high mortality and morbidity. Despite extensive research, there are only a very limited number of therapeutic approaches suitable for treatment of stroke patients as yet. Mounting evidence has demonstrated that such gases as oxygen, hydrogen and hydrogen sulfide are able to provide neuroprotection after stroke. In this paper, we will focus on the recent two years’ progress in the development of gas therapies of stroke and in understanding the molecular mechanisms underlying protection induced by medical gases. We will also discuss the advantages and challenges of these approaches and provide information for future study.