Suberoylanilide hydroxamic acid (SAHA) alleviates the learning and memory impairment in rat offspring caused by maternal sevoflurane exposure during late gestation

Myricetin Mitigated Sevoflurane-induced Cognitive Dysfunction in Aged-mice Through Inhibiting Histone Deacetylase 2/nuclear Factor Erythroid 2-related Factor 2/heme Oxygenase-1 Signalling-mediated Ferroptosis and Mitochondrial Dysfunction

Sevoflurane anaesthesia induces neurotoxicity and postoperative cognitive dysfunction (POCD) after surgery. This study investigated the roles and potential mechanisms of the natural flavonoid myricetin in sevoflurane-induced cognitive dysfunction. Primary hippocampal neurons were treated with 3% sevoflurane to establish a neuron injury model. Neurons was pre-treated with different concentrations of myricetin, and ferroptosis inhibitor ferrostatin-1 (Fer-1) was used as a positive control. Moreover, mice were anaesthetised with 3% sevoflurane to establish an in-vivo model, and they were pre-treated with 50 or 100 m/kg myricetin. Cell viability and death were determined. Ferroptosis-related markers, including intracellular iron content, reactive oxygen species (ROS), malondialdehyde (MDA), glutathione (GSH), 4-hydroxy-2-nonenal (4-HNE), glutathione peroxidase 4 (GPX4) and solute carrier family 7 member 11 (SLC7A11) protein levels were measured. Myricetin treatment enhanced cell viability and mitigated sevoflurane-induced cell death in the hippocampal neurons. Sevoflurane exposure increased the ROS, MDA and 4-HNE levels and reduced the GSH level, whereas myricetin treatment abrogated these effects. Meanwhile, myricetin treatment restrained sevoflurane-induced increase in intracellular iron content and GPX4 and SLC7A11 protein levels. A high dose of myricetin showed distinct protective effects. Mechanistic studies demonstrated that myricetin treatment reversed sevoflurane-induced histone deacetylase 2 (HDAC2) upregulation and nuclear factor erythroid 2-related factor 2 (Nrf2) deacetylation, thus activating the Nrf2/heme oxygenase-1 (HO-1) signalling. Myricetin treatment mitigated sevoflurane-induced cognitive dysfunction in aged mice by inhibiting hippocampal ferroptosis and mitochondrial dysfunction via the HDAC2/Nrf2/HO-1 signalling pathway. Myricetin may be a treatment option for POCD after surgery.

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.

The m6A Reader YTHDF1 Improves Sevoflurane-Induced Neuronal Pyroptosis and Cognitive Dysfunction Through Augmenting CREB-BDNF Signaling

Sevoflurane is one of the most widely used anesthetics in surgery which is the main cause of postoperative cognitive dysfunction (POCD). Previous reports confirmed that YTHDF1 is differently expressed in sevoflurane-induced POCD, while the roles and mechanistic details remain unclear. The molecular expressions were assessed using qRT-PCR, western blot, immunofluorescence and immunohistochemistry. Pathological change in the hippocampus tissues was analyzed using HE staining. Cognitive ability in rats was measured using MWM test. Hippocampal neuronal viability and apoptosis were measured by MTT assay and flow cytometry, respectively. The levels of pro-inflammatory cytokines were assessed using ELISA. The interaction between YTHDF1 and CREB was analyzed by RNA immunoprecipitation assay. YTHDF1 was significantly decreased in hippocampus tissues by sevoflurane exposure, and its overexpression could improve sevoflurane-induced neuron damage and cognitive dysfunction. Meanwhile, YTHDF1 upregulation repressed sevoflurane-induced activation of NLRP3 inflammation and pyroptosis in hippocampus tissues. Subsequently, YTHDF1 directly interacted to CREB mRNA to augment its stability and translation via a m6A-dependent manner, thus activating CREB/BDNF pathway. In addition, the inactivation of CREB/BDNF pathway could reverse the protective effects of YTHDF1 overexpression on sevoflurane-mediated neuronal damage and pyroptosis. These findings revealed that YTHDF1 improved sevoflurane-induced neuronal pyroptosis and cognitive dysfunction through activating CREB-BDNF signaling.

Effects of Sevoflurane Exposure on Fetal Brain Development Using Cerebral Organoids

Sevoflurane is a safe and well-known inhaled anesthetic. Given that sevoflurane can be delivered to developing fetuses through the mother, it is critical to determine whether this agent affects fetal neurodevelopment. Recent research has sought to determine whether sevoflurane affects fetal brain development when the mother is exposed during the second to third trimester of pregnancy, considered to be the crucial period for the development of nervous system. However, even though the first trimester is a critical period for fetal organogenesis and the most susceptible time to teratogen exposure, research regarding the effects of sevoflurane on organogenesis, especially on brain development, is insufficient. In the present study, human embryonic stem cells (hESC)-derived cerebral organoids were exposed to sevoflurane during the time corresponding to the first trimester to investigate the effect of early sevoflurane exposure on fetal brain development, specifically the processes of neuronal differentiation and maturation. Organoid size exposed to the intermediate concentration of sevoflurane did not differ from control, immunofluorescence demonstrated that sevoflurane temporarily decreased the size of SOX2 + /N-cad + ventricular zone structures only during the mid-time point, and upregulated expression of TUJ1 and MAP2 only during the early time point. However, all markers returned to normal levels, and organoids formed normal cortical structures at the late time point. Our results suggest that maternal sevoflurane exposure during the first trimester of pregnancy can cause abnormal neuronal differentiation in the fetal brain. However, considering the recovery observed in later periods, sevoflurane exposure might not have lasting impacts on fetal brain development.

Research progress on molecular mechanisms of general anesthetic-induced neurotoxicity and cognitive impairment in the developing brain

General anesthetics-induced neurotoxicity and cognitive impairment in developing brains have become one of the current research hotspots in the medical science community. The underlying mechanisms are complex and involve various related molecular signaling pathways, cell mediators, autophagy, and other pathological processes. However, few drugs can be directly used to treat neurotoxicity and cognitive impairment caused by general anesthetics in clinical practice. This article reviews the molecular mechanism of general anesthesia-induced neurotoxicity and cognitive impairment in the neonatal brain after surgery in the hope of providing critical references for the treatments of clinical diseases.

MicroRNA-495 suppresses pre-eclampsia via activation of p53/PUMA axis

Linkage between microRNAs (miRNAs) and pre-eclampsia (PE) has been documented. Here, we focused on miR-495 in PE and its underlying mechanism in regulation of trophoblast cells. Expression of miR-495, HDAC2, p53 and PUMA was determined in collected placental tissue samples. Loss- and gain-function was performed to determine the roles of miR-495, HDAC2, p53, and PUMA in biological processes of HTR8/SVneo cells and primary trophoblast cells. The relationships among miR-495, HDAC2, and p53 were pinpointed. PE patients presented with higher expression of miR-495, p53, and PUMA in placental tissues, but lower HDAC2. miR-495 negatively targeted HDAC2 expression. HDAC2 suppressed p53 expression via deacetylation. Overexpression of miR-495, p53, or PUMA inhibited biological properties of HTR8/SVneo cells and primary trophoblast cells, while opposite trends were observed in response to oe-HDAC2. In conclusion, miR-495 knockdown can suppress p53/PUMA axis by targeting HDAC2 to enhance biological behaviors of trophoblast cells, which may prevent occurrence of PE.

Repurposing Vorinostat for the Treatment of Disorders Affecting Brain

Based on the findings in recent years, we summarize the therapeutic potential of vorinostat (VOR), the first approved histone deacetylase (HDAC) inhibitor, in disorders of brain, and strategies to improve drug efficacy and reduce side effects. Scientific evidences provide a strong case for the therapeutic utility of VOR in various disorders affecting brain, including stroke, Alzheimer's disease, frontotemporal dementia, Parkinson's disease, Huntington's disease, amyotrophic lateral sclerosis, spinal muscular atrophy, X-linked adrenoleukodystrophy, epilepsy, Niemann-Pick type C disease, and neuropsychiatric disorders. Further elucidation of the neuroprotective and neurorestorative properties of VOR using proper clinical study designs could provide momentum towards its clinical application. To improve the therapeutic prospect, concerns on systemic toxicity and off-target actions need to be addressed along with the improvement in formulation and delivery aspects, especially with respect to solubility, permeability, and pharmacokinetic properties. Newer approaches in this regard include poly(ethylene glycol)-b-poly(DL-lactic acid) micelles, VOR-pluronic F127 micelles, encapsulation of iron complexes of VOR into PEGylated liposomes, human serum albumin bound VOR nanomedicine, magnetically guided layer-by-layer assembled nanocarriers, as well as convection-enhanced delivery. Even though targeting specific class or isoform of HDAC is projected as advantageous over pan-HDAC inhibitor like VOR, in terms of adverse effects and efficacy, till clinical validation, the idea is debated. As the VOR treatment-related adverse changes are mostly found reversible, further optimization of the therapeutic strategies with respect to dose, dosage regimen, and formulations of VOR could propel its clinical prospects.

Expression of histone deacetylase 2 in tracheal stenosis models and its relationship with tracheal granulation tissue proliferation

The current treatments for benign tracheal stenosis are inefficient. The present study examined the expression of histone deacetylase 2 (HDAC2) in different tracheal stenosis models and explored its association with the proliferation of tracheal granulation tissue and its ability to constitute a potential therapy for tracheal stenosis. Animal tracheal stenosis models were established, as indicated by hematoxylin and eosin (H&E) staining. A total of 24 New Zealand White rabbits were randomly divided into control, erythromycin, budesonide and vorinostat groups. Stenotic tracheal tissues were collected on day 11 after drug administration for 10 days. The degree of tracheal stenosis in each group was calculated, and pathological alterations were observed using H&E staining. The mRNA expression of HDAC2, interleukin-8 (IL-8), transforming growth factor-β1 (TGF-β1) and vascular endothelial growth factor (VEGF) was examined via reverse transcription-quantitative PCR. The protein expression of HDAC2 was examined via immunofluorescence, while the expression of type I and type III collagen was assessed using immunohistochemistry. The results of the present study demonstrated that tracheal epithelial hyperplasia in the erythromycin group was improved, the degree of hyperplasia being the lowest among all groups, and tracheal stenosis was reduced compared with the control group. In the vorinostat group, tracheal epithelial tissue hyperplasia was aggravated and stenosis was increased. The HDAC2 mRNA and protein levels were increased and decreased in the erythromycin and vorinostat groups, respectively. In contrast, the IL-8 mRNA expression levels were decreased and increased in the erythromycin and vorinostat groups, respectively. TGF-β1, VEGF, type I and type III collagen expression was decreased in the erythromycin group, while TGF-β1, VEGF and type III collagen expression was increased in the vorinostat group. Compared with the control, the budesonide group did not exhibit any alterations in all of the indicators examined, including TGF-β1, VEGF, IL-8, HDAC2 and collagen. Erythromycin treatment upregulated the expression of HDAC2, inhibited the inflammatory responses and reduced the proliferation of tracheal granulation tissue. In contrast, vorinostat treatment downregulated HDAC2 expression, promoted the inflammatory responses and increased the proliferation of tracheal granulation tissue. These results suggest that regulating HDAC2 may be used as a potential treatment for benign tracheal stenosis.