Multiple sevoflurane exposures during mid-trimester induce neurotoxicity in the developing brain initiated by 15LO2-Mediated ferroptosis

Research progress in the clinical application of inhaled anesthetic sevoflurane

Sevoflurane has been widely used in clinical anesthesia as an inhalation anesthetic. With the development of medicine, there have been several new applications in recent years, such as daytime surgery, labor analgesia, and combined nerve block for some surgeries. Moreover, as research progresses, it has been found that it not only has potential organ protection effects but can also be used to treat severe asthma and relieve the tracheal spasm state. In addition, local administration can effectively treat vascular ulcers. We briefly review the organ protective effect of sevoflurane, its application in dental treatment, asthma treatment, vascular ulcer treatment and some new progress in clinical application.

Up-regulation of miR-490-3p improves learning/memory disability of sevoflurane exposure by relieving neuroinflammation

Our study focused on the potential mechanism of microRNA-490-3p (miR-490-3p) on learning/memory disability of rats resulting from sevoflurane (Sev). The rat model of cognitive dysfunction was established by infection with miR-490-3p mimic and Sev-exposure. Morris water maze and open field test assay were used for the assessment of cognitive deficits. Enzyme-linked immunosorbent assay and quantitative real-time polymerase chain reaction assays were used for the measurements of neuroinflammatory cytokines and inflammatory-related genes in respective order. Bioinformatics analysis was employed for the predictive miR-490-3p-related genes. The targeted interaction was verified via dual-luciferase reporter assay. A significant decline of miR-490-3p was discovered in rats with Sev treatment, while the levels were up-regulated in rats with infection miR-490-3p pretreatment (P < 0.001). For Sev-induced rats, the stay time in the target quadrant was shorten, while distance travelled lengthened significantly with the control group by comparison (P < 0.001). Notably, an increased time of the escape latency and a decreased number of platform crossings were found in the Sev group, which alleviated by infection with miR-490-3p mimic pretreatment (P < 0.001). Moreover, the neuroinflammatory cytokines were elevated in the Sev group, the effects of which were recovered via miR-490-3p pretreatment (P < 0.001). Bioinformatics analysis predicted the miR-490-3p-associated genes. CDK1 (Cyclin-dependent kinase 1) was a potential target gene of miR-490-3p, which confirmed by dual-luciferase reporter detection. MiR-490-3p alleviated the learning and memory deficits in Sev-treated rats via the modulation of CDK1.

Unraveling the effects of prenatal anesthesia on neurodevelopment: A review of current evidence and future directions

Human brain development is a complex, multi-stage, and sensitive process, especially during the fetal stage. Animal studies over the last two decades have highlighted the potential risks of anesthetics to the developing brain, impacting its structure and function. This has raised concerns regarding the safety of anesthesia during pregnancy and its influence on fetal brain development, garnering significant attention from the anesthesiology community. Although preclinical studies predominantly indicate the neurotoxic effects of prenatal anesthesia, these findings cannot be directly extrapolated to humans due to interspecies variations. Clinical research, constrained by ethical and technical hurdles in accessing human prenatal brain tissues, often yields conflicting results compared to preclinical data. The emergence of brain organoids as a cutting-edge research tool shows promise in modeling human brain development. When integrated with single-cell sequencing, these organoids offer insights into potential neurotoxic mechanisms triggered by prenatal anesthesia. Despite several retrospective and cohort studies exploring the clinical impact of anesthesia on brain development, many findings remain inconclusive. As such, this review synthesizes preclinical and clinical evidence on the effects of prenatal anesthesia on fetal brain development and suggests areas for future research advancement.

Unraveling the role and mechanism of mitochondria in postoperative cognitive dysfunction: a narrative review

Postoperative cognitive dysfunction (POCD) is a frequent neurological complication encountered during the perioperative period with unclear mechanisms and no effective treatments. Recent research into the pathogenesis of POCD has primarily focused on neuroinflammation, oxidative stress, changes in neural synaptic plasticity and neurotransmitter imbalances. Given the high-energy metabolism of neurons and their critical dependency on mitochondria, mitochondrial dysfunction directly affects neuronal function. Additionally, as the primary organelles generating reactive oxygen species, mitochondria are closely linked to the pathological processes of neuroinflammation. Surgery and anesthesia can induce mitochondrial dysfunction, increase mitochondrial oxidative stress, and disrupt mitochondrial quality-control mechanisms via various pathways, hence serving as key initiators of the POCD pathological process. We conducted a review on the role and potential mechanisms of mitochondria in postoperative cognitive dysfunction by consulting relevant literature from the PubMed and EMBASE databases spanning the past 25 years. Our findings indicate that surgery and anesthesia can inhibit mitochondrial respiration, thereby reducing ATP production, decreasing mitochondrial membrane potential, promoting mitochondrial fission, inducing mitochondrial calcium buffering abnormalities and iron accumulation, inhibiting mitophagy, and increasing mitochondrial oxidative stress. Mitochondrial dysfunction and damage can ultimately lead to impaired neuronal function, abnormal synaptic transmission, impaired synthesis and release of neurotransmitters, and even neuronal death, resulting in cognitive dysfunction. Targeted mitochondrial therapies have shown positive outcomes, holding promise as a novel treatment for POCD.

Comprehensive review of perioperative factors influencing ferroptosis

The perioperative period encompasses all phases of patient care from the decision to perform surgery until full recovery. Ferroptosis, a newly identified type of regulated cell death, influences a wide array of diseases, including those affecting the prognosis and regression of surgical patients, such as ischemia-reperfusion injury and perioperative cognitive dysfunction. This review systematically examines perioperative factors impacting ferroptosis such as surgical trauma-induced stress, tissue hypoxia, anesthetics, hypothermia, and blood transfusion. By analyzing their intrinsic relationships, we aim to improve intraoperative management, enhance perioperative safety, prevent complications, and support high-quality postoperative recovery, ultimately improving patient outcomes.

Unveiling the hidden dangers: a review of non-apoptotic programmed cell death in anesthetic-induced developmental neurotoxicity

Anesthetic-induced developmental neurotoxicity (AIDN) can arise due to various factors, among which aberrant nerve cell death is a prominent risk factor. Animal studies have reported that repeated or prolonged anesthetic exposure can cause significant neuroapoptosis in the developing brain. Lately, non-apoptotic programmed cell deaths (PCDs), characterized by inflammation and oxidative stress, have gained increasing attention. Substantial evidence suggests that non-apoptotic PCDs are essential for neuronal cell death in AIDN compared to apoptosis. This article examines relevant publications in the PubMed database until April 2024. Only original articles in English that investigated the potential manifestations of non-apoptotic PCD in AIDN were analysed. Specifically, it investigates necroptosis, pyroptosis, ferroptosis, and parthanatos, elucidating the signaling mechanisms associated with each form. Furthermore, this study explores the potential relevance of these non-apoptotic PCDs pathways to the pathological mechanisms underlying AIDN, drawing upon their distinctive characteristics. Despite the considerable challenges involved in translating fundamental scientific knowledge into clinical therapeutic interventions, this comprehensive review offers a theoretical foundation for developing innovative preventive and treatment strategies targeting non-apoptotic PCDs in the context of AIDN.

Ferroptosis implication in environmental-induced neurotoxicity

Neurotoxicity, stemming from exposure to various chemical, biological, and physical agents, poses a substantial threat to the intricate network of the human nervous system. This article explores the implications of ferroptosis, a regulated form of programmed cell death characterized by iron-dependent lipid peroxidation, in environmental-induced neurotoxicity. While apoptosis has historically been recognized as a primary mechanism in neurotoxic events, recent evidence suggests the involvement of additional pathways, including ferroptosis. The study aims to conduct a comprehensive review of the existing literature on ferroptosis induced by environmental neurotoxicity across diverse agents such as natural toxins, insecticides, particulate matter, acrylamide, nanoparticles, plastic materials, metal overload, viral infections, anesthetics, chemotherapy, and radiation. The primary objective is to elucidate the diverse mechanisms through which these agents trigger ferroptosis, leading to neuronal cell death. Furthermore, the article explores potential preventive or therapeutic strategies that could mitigate ferroptosis, offering insights into protective measures against neurological damage induced by environmental stressors. This comprehensive review contributes to our evolving understanding of neurotoxicological processes, highlighting ferroptosis as a significant contributor to neuronal cell demise induced by environmental exposures. The insights gained from this study may pave the way for the development of targeted interventions to protect against ferroptosis-mediated neurotoxicity and ultimately safeguard public health.

The miR-182-5p/GPX4 Pathway Contributes to Sevoflurane-Induced Ototoxicity via Ferroptosis

Our study aimed to investigate the role of ferroptosis in sevoflurane-induced hearing impairment and explore the mechanism of the microRNA-182-5p (miR-182-5p)/Glutathione Peroxidase 4 (GPX4) pathway in sevoflurane-induced ototoxicity. Immunofluorescence staining was performed using myosin 7a and CtBP2. Cell viability was assessed using the CCK-8 kit. Fe2+ concentration was measured using FerroOrange and Mi-to-FerroGreen fluorescent probes. The lipid peroxide level was assessed using BODIPY 581/591 C11 and MitoSOX fluorescent probes. The auditory brainstem response (ABR) test was conducted to evaluate the hearing status. Bioinformatics tools and dual luciferase gene reporter analysis were used to confirm the direct targeting of miR-182-5p on GPX4 mRNA. GPX4 and miR-182-5p expression in cells was assessed by qRT-PCR and Western blot. Ferrostatin-1 (Fer-1) pretreatment significantly improved hearing impairment and damage to ribbon synapses in mice caused by sevoflurane exposure. Immunofluorescence staining revealed that Fer-1 pretreatment reduced intracellular and mitochondrial iron overload, as well as lipid peroxide accumulation. Our findings indicated that miR-182-5p was upregulated in sevoflurane-exposed HEI-OC1 cells, and miR-182-5p regulated GPX4 expression by binding to the 3'UTR of GPX4 mRNA. The inhibition of miR-182-5p attenuated sevoflurane-induced iron overload and lipid peroxide accumulation. Our study elucidated that the miR-182-5p/GPX4 pathway was implicated in sevoflurane-induced ototoxicity by promoting ferroptosis.

Dysregulation of iron homeostasis and ferroptosis in sevoflurane and isoflurane associated perioperative neurocognitive disorders

In recent years, sevoflurane and isoflurane are the most popular anesthetics in general anesthesia for their safe, rapid onset, and well tolerant. Nevertheless, many studies reported their neurotoxicity among pediatric and aged populations. This effect is usually manifested as cognitive impairment such as perioperative neurocognitive disorders. The wide application of sevoflurane and isoflurane during general anesthesia makes their safety a major health concern. Evidence indicates that iron dyshomeostasis and ferroptosis may establish a role in neurotoxicity of sevoflurane and isoflurane. However, the mechanisms of sevoflurane- and isoflurane-induced neuronal injury were not fully understood, which poses a barrier to the treatment of its neurotoxicity. We, therefore, reviewed the current knowledge on mechanisms of iron dyshomeostasis and ferroptosis and aimed to promote a better understanding of their roles in sevoflurane- and isoflurane-induced neurotoxicity.