Reducing complement activation during sleep deprivation yields cognitive improvement by dexmedetomidine

Exploring the effect and mechanism of action of Jinlida granules (JLD) in the treatment of diabetes-associated cognitive impairment based on network pharmacology with experimental validation

OBJECTIVES

To explore the effect and the probable mechanisms of JLD in the treatment of type 2 diabetes mellitus (T2DM) - associated cognitive impairment (TDACI).

METHODS

The effect of JLD in combating TDACI was assessed in T2DM model mice by conducting Morris water maze (MWM) behaviour testing. Active components and their putative targets, as well as TDACI-related targets, were collected from public databases. Protein-protein interactions (PPIs), Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses and molecular docking were then utilized to explore potential molecular network mechanisms. Finally, the main targets were verified in animal model experiments.

RESULTS

MWM test showed that JLD improved aspects of behaviour in T2DM model mice. JLD improved glucose intolerance, tissue insulin sensitivity, lipid metabolism and enhanced synapse-associated protein expression in hippocampus tissue. Network pharmacology revealed 185 active components, 337 targets of JLD, and 7998 TDACI related targets were obtained . PPI network analyses revealed 39 core targets. GO and KEGG analyses suggested that JLD might improve TDACI by regulating gene expression, apoptotic processes and inflammatory responses mainly via PI3K-AKT and AGE-RAGE signaling pathways. Molecular docking revealed strong binding of the main components to core targets. JLD reduced hippocampus tissue expression of the inflammatory cytokines tumor necrosis factor-α (TNF-α) and interleukin-6 (IL6), core targets of treatment of TDACI.

CONCLUSIONS

The findings suggested that JLD has the potential to improve TDACI through multiple components, multiple targets and multiple pathways. JLD may be a promising treatment for diabetic cognitive impairment.

Vitamin K2 mitigates cognitive, and motor impairments induced by multiple surgery with anesthesia and analgesia in neonatal stage

Anesthesia and analgesia are essential components for surgical procedures. While the neurotoxic effects of multiple anesthesia exposures during brain development are well established, the combined impact of multiple surgery with anesthesia and analgesia exposures on neurodevelopmental remains unknown. In this study, neonatal mice underwent multiple surgery with fentanyl and sevoflurane (MSFS) exposures on postnatal days 6, 8, and 10, resulting in attention deficit hyperactivity disorder (ADHD)-like hyperactivity, impulsive behavior, cognitive impairment, and fine motor dysfunction in adulthood. Additionally, MSFS exposures inhibited neurogenesis in the nucleus accumbens (NAc) by reducing neural stem cells (NSCs) proliferation and differentiation into neurons and astrocytes. Pre-administration of Vitamin K2 (VK2) 30 min before each MSFS procedure significantly mitigated the behavioral impairments and restored neurogenesis. RNA-sequencing revealed that MSFS treatment induced 75 up-regulated and 140 down-regulated differentially expressed genes (DEGs) in the NAc, while VK2 pre-administration resulted in 149 up-regulated and 56 down-regulated DEGs. Among these, 32 DEGs were down-regulated by MSFS but restored by VK2 and 12 DEGs were up-regulated by MSFS but down-regulated by VK2. To identify key regulatory genes modulated by VK2, we performed protein-protein interaction analysis using CytoHubba, which revealed 10 hub genes-DLGAP5, TPX2, KIF20B, PLK1, SGO1, GTSE1, ASPM, CDCA2, BUB1B, and NUSAP1-with critical roles in cell cycle, cell division and NSCs pathways. The expression of hub genes was validated by RT-qPCR and immunofluorescence staining. These findings suggest that MSFS-induces ADHD-like behaviors, cognitive impairment, fine motor dysfunction, impaired neurogenesis and altering genes expression involved in cell cycle, cell division and NSCs pathways, which are rescued by VK2. This study presents the clinically MSFS model for investigating neurodevelopmental toxicity and highlights VK2's potential as a neuroprotective agent in pediatric involving multiple surgery with anesthesia and analgesia.

Oxidative Stress-mediated Loss of Hippocampal Parvalbumin Interneurons Contributes to Memory Precision Decline After Acute Sleep Deprivation

Sleep is pivotal to memory consolidation, and sleep deprivation (SD) after learning can impede this process, leading to memory disorders. In the present study, we aimed to explore the effects of acute sleep deprivation (ASD) on memory disorders and the underlying mechanisms. ASD model was induced by subjecting the mice to 6 h of SD following fear conditioning training. Different cohorts were used for behavioral, biochemical, and electrophysiological tests. Here, we showed that memory precision decline was induced by ASD, concomitant with a notable elevation in oxidative stress within PV interneurons, loss of PV, and disturbed neuronal oscillation in the CA1 region. Notably, chemogenetic activation of PV interneurons effectively ameliorated abnormal gamma oscillation and memory precision decline observed in ASD mice. Meanwhile, chemogenetic inhibition of PV interneurons successfully mimicked the abnormal brain oscillations and memory precision decline observed in ASD mice. Additionally, prior administration of the antioxidant medication N-acetylcysteine effectively reversed memory precision decline and mitigated PV loss and abnormal oscillation triggered by ASD. Collectively, our findings indicated that ASD increased oxidative stress in PV interneurons, thereby disrupting neural oscillation in the CA1 and ultimately leading to memory precision decline.

Sex differences in reward-based operant conditioning performance and neurotransmitter changes following chronic sleep restriction stress in rats

BACKGROUND

Sleep deprivation significantly impairs cognitive function, which disrupts daily life. However, sex differences in these impairments are not well understood, as most preclinical studies primarily use male animals, neglecting potential differences between sexes. This study aims to investigate sex-specific differences in cognitive function under sleep deprivation using reward-based operant conditioning tasks.

RESULTS

Sprague-Dawley rats were pre-trained on a lever-press task and subsequently divided into control and chronic sleep restriction (CSR) groups. The CSR group underwent 14 days of sleep restriction. After CSR modeling, rats were assessed using the open field test, retraining on the lever-pressing task, signal discrimination task, and extinction task to evaluate motor abilities, memory formation, learning, and cognitive flexibility. CSR significantly impaired task performance in both sexes, with rats requiring more time and exhibiting lower accuracy. In the signal discrimination task, male rats showed longer feeding latency and lower accuracy compared to females. CSR also specifically increased the frequency of operant responses in male rats. In the extinction task, CSR enhanced exploration time and frequency in both sexes, with females exhibiting significantly higher exploration frequencies than males. Biochemically, CSR induced sex-specific alterations, including elevated serum MDA and MAO levels in males and increased serotonin, dopamine, and epinephrine in both sexes. Although activation was observed in metabolites of the tryptophan-kynurenine pathway, sex differences were evident in the kynurenic acid metabolism levels in the prefrontal cortex.

CONCLUSIONS

CSR impairs cognitive function in both male and female rats, with significant sex differences observed. Male CSR rats exhibited impaired signal discrimination, while CSR impaired extinction learning in female rats. These impairments are accompanied by CSR-induced oxidative stress, neurotransmitter dysregulation, and disturbances in the tryptophan metabolic pathway. These findings underscore the importance of considering sex differences in understanding the effects of sleep deprivation on cognitive function and developing targeted intervention strategies.

SCH58261 effectively prevents the reduction in excitability of striatal MSNs in mice following 20 h of sleep deprivation

Adenosine, a sleep-associated neuromodulator, is crucial in various physiological and pathological processes. Previous studies have demonstrated that sleep deprivation (SD) alters striatal neuronal activity. In this study, we used in vitro electrophysiological recordings to investigate the effects of 20 h of SD on the neuronal excitability of mouse dorsal striatal medium spiny neurons (MSNs). Our findings revealed that SD resulted in altered action potential (AP) discharge properties and reduced neuronal excitability compared to the control group. Importantly, these changes were partially offset by the prophylactic injection of the A2A receptor (A2AR) antagonist SCH58261. Additionally, 20 h of SD caused a decrease in the amplitude and an increase in the interval of spontaneous excitatory postsynaptic currents (sEPSCs) compared to control. However, the prophylactic injection of the A2AR antagonism shortened the sEPSC interval, while the A1 receptor (A1R) antagonist DPCPX not only shortened the interval but also further reduced the amplitude of sEPSCs. Thus, it can be concluded that SCH58261 effectively prevents the reduction in excitability of striatal MSNs in mice following 20 h of sleep deprivation, whereas DPCPX does not.

The activation of microglia by the complement system in neurodegenerative diseases

Neurodegenerative diseases (NDDs) are a group of neurological disorders characterized by the progressive loss of neuronal structure and function, leading to cognitive and behavioral impairments. Despite significant research advancements, there is currently no definitive cure for NDDs. With global aging on the rise, the burden of these diseases is becoming increasingly severe, highlighting the urgency of understanding their pathogenesis and developing effective therapeutic strategies. Microglia, specialized macrophages in the central nervous system, play a dual role in maintaining neural homeostasis. They are involved in clearing cellular debris and apoptotic cells, but in their activated state, they release inflammatory factors that contribute significantly to neuroinflammation. The complement system (CS), a critical component of the innate immune system, assists in clearing damaged cells and proteins. However, excessive or uncontrolled activation of the CS can lead to chronic neuroinflammation, exacerbating neuronal damage. This review aims to explore the roles of microglia and the CS in the progression of NDDs, with a specific focus on the mechanisms through which the CS activates microglia by modulating mitochondrial function. Understanding these interactions may provide insights into potential therapeutic targets for mitigating neuroinflammation and slowing neurodegeneration.

Remimazolam alleviates sleep deprivation induced anxiety-like behaviors via regulating the STING pathway

Sleep loss becomes a major problem in modern life and increases the incidence of anxiety disorders. Benzodiazepines are the most commonly used anxiolytic medications. Remimazolam is an ultra-short-acting benzodiazepine, which has been shown to reduce the preoperative anxiety levels in patients. However, the effects on anxiety-like behaviors caused by chronic sleep deprivation (CSD) and the underlying molecular mechanisms remain unclear. Here, we found that administration of remimazolam can effectively alleviate anxiety-like behaviors induced by CSD. Furthermore, remimazolam can significantly preserve the sleep deprivation-induced deficits in neuronal calcium activity in CA1 of the hippocampus. In addition, stimulator of interferon genes (STING) was activated in CA1 after CSD, while remimazolam was sufficient to block the activation of the STING pathway. Further study showed that inhibiting the activation of STING also effectively alleviates the anxiety symptoms induced by CSD. Overall, our research offers new insight and a promising therapeutic agent for the anxiety disorders caused by sleep deprivation.

WuYou decoction effectively reduces neuronal damage, synaptic dysfunction, and Aβ production in rats exposed to chronic sleep deprivation by modulating the Aβ-related enzymes and SIRT1/Nrf2/NF-κB pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Chronic sleep deprivation (CSD) can result in neuronal damage, synaptic dysfunction, Aβ production, neuroinflammation, and ultimately cognitive deterioration. WuYou Decoction (WYD), a contemporary prescription, has shown promise in enhancing sleep quality and cognitive performance in individuals with insomnia. However, the specific molecular mechanisms responsible for the neuroprotective effects of WYD on CSD remain incompletely understood.

AIM OF THE STUDY

This study aimed to investigate the neuroprotective effects of WYD on the CSD model and its molecular mechanism.

MATERIALS AND METHODS

UHPLC-MS/MS analysis was utilized to analyze the active ingredients of WYD extract. The study employed the multi-platform water environment method to establish the CSD model in rats. Subsequent to treatment with varying doses of WYD in CSD rats, cognitive function and pathological alterations in hippocampus and cortex, including neuronal damage, synaptic dysfunction, Aβ production, and neuroinflammation, were evaluated through a combination of Morris Water Maze test, HE staining, Nissl staining, Golgi-Cox staining, Transmission electron microscope, ELISA, Immunohistochemistry staining, Immunofluorescence staining and Western blot.

RESULTS

UHPLC-MS/MS analysis revealed a total of 99 active ingredients were identified from the WYD extract. The administration of WYD exhibited a mitigation of cognitive decline in the model of CSD, as evidenced by increased neuron count in the hippocampus and cortex, and improved density and length of dendritic spines in these brain regions. Furthermore, WYD was found to suppress the Aβ production, and inhibit the expression of BACE1, PS1, GFAP, IBA1, IL-1β, IL-6, TNF-α, phosphorylated IκBα (Ser32) and phosphorylated NF-κB p65 (Ser536) in the hippocampus and cortex, while also increasing the levels of PSD95, SYN1, ADAM10, IDE, SIRT1 and Nrf2.

CONCLUSIONS

WYD exhibits neuroprotective properties in CSD, potentially through modulation of the Aβ-related enzymes and SIRT1/Nrf2/NF-κB pathway.

S100A8 knockdown activates the PI3K/AKT signaling pathway to inhibit microglial autophagy and improve cognitive impairment mediated by chronic sleep deprivation

OBJECTIVE

Cognitive dysfunction is one of the major symptoms of chronic sleep deprivation (CSD). Abnormal autophagy and apoptosis are thought to be important mechanisms. S100 Calcium Binding Protein A8 (S100A8) plays a key role in autophagy and apoptosis of microglia. This study investigated whether S100A8 knockdown can effectively inhibit aberrant autophagy in microglia and improve cognitive function by activating the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) signaling pathway under CSD conditions.

METHODS

CSD mouse models and BV2 cell autophagy models were established in vivo and in vitro. Transcriptome sequencing was used to determine the key regulator related to autophagy. The Morris water maze test was used to evaluate the cognitive behavior of the mice. RT-qPCR and western blot were conducted to examine S100A8 expression and autophagy signalling. HE, TUNEL, transmission electron microscopy, immunofluorescence, and histochemistry were performed to detect pathological changes, neuronal autophagy, apoptosis, or positive cells in hippocampal tissues, respectively.

RESULTS

Transcriptome sequencing showed that S100A8 was significantly elevated in CSD mice, and fluorescence colocalization results further suggested that S100A8 mainly colocalizes with microglia. In vivo studies revealed that knockdown of S100A8 alleviated CSD-induced cognitive impairment in mice. Through further mechanistic investigations employing both in vivo and in vitro models, we demonstrated that silencing S100A8 can activate the PI3K/AKT pathway, thereby reducing CSD-induced abnormal autophagy and apoptosis in microglia. Aberrant autophagy and apoptosis in microglia were reversed with the PI3K/AKT pathway inhibitor LY294002.

CONCLUSION

The S100A8/PI3K/AKT axis plays a crucial role in chronic sleep deprivation-mediated autophagy and apoptosis in microglia.

Anesthetic spindles serve as EEG markers of the depth variations in anesthesia induced by multifarious general anesthetics in mouse experiments

Background

Mice play a crucial role in studying the mechanisms of general anesthesia. However, identifying reliable EEG markers for different depths of anesthesia induced by multifarious agents remains a significant challenge. Spindle activity, typically observed during NREM sleep, reflects synchronized thalamocortical activity and is characterized by a frequency range of 7-15 Hz and a duration of 0.5-3 s. Similar patterns, referred to as "anesthetic spindles," are also observed in the EEG during general anesthesia. However, the variability of anesthetic spindles across different anesthetic agents and depths is not yet fully understood.

Method

Mice were anesthetized with dexmedetomidine, propofol, ketamine, etomidate, isoflurane, or sevoflurane, and cortical EEG recordings were obtained. EEG signals were bandpass filtered between 0.1 and 60 Hz and analyzed using a custom MATLAB script for spindle detection. Anesthesia depth was assessed based on Guedel's modified stages of anesthesia and the presence of burst suppression in the EEG.

Results

Compared to sleep spindles, anesthetic spindles induced by the different agents exhibited higher amplitudes and longer durations. Isoflurane- and sevoflurane-induced spindles varied with the depth of anesthesia. Spindles associated with etomidate were prominent during induction and light anesthesia, whereas those induced by sevoflurane and isoflurane were more dominant during deep anesthesia and emergence. Post-anesthesia, spindles persisted but ceased more quickly following inhalational anesthesia.

Conclusion

Anesthesia spindle waves reflect distinct changes in anesthesia depth and persist following emergence, serving as objective EEG markers for assessing both anesthesia depth and the recovery process.

Continuous Theta Burst Stimulation Inhibits Oxidative Stress-Induced Inflammation and Autophagy in Hippocampal Neurons by Activating Glutathione Synthesis Pathway, Improving Cognitive Impairment in Sleep-Deprived Mice

Sleep deprivation (SD) has been reported to have a negative impact on cognitive function. Continuous theta burst stimulation (cTBS) shows certain effects in improving sleep and neurological diseases, and its molecular or cellular role in SD-induced cognition impairment still need further exploration. In this study, C57BL/6 mice were subjected to 48 h of SD and cTBS treatment, and cTBS treatment significantly improved SD-triggered impairment of spatial learning and memory abilities in mice. Additionally, cTBS reduced malondialdehyde levels, increased superoxide dismutase activities, and inhibited the production of inflammatory cytokines, alleviating oxidative stress and inflammation levels in hippocampal tissues of SD model mice. cTBS decreased LC3II/LC3I ratio, Beclin1 protein levels, and LC3B puncta intensity, and elevated p62 protein levels to suppress excessive autophagy in hippocampal tissues of SD-stimulated mice. Then, we proved that inhibiting oxidative stress alleviated inflammation, autophagy, and death of hippocampal neuron cells through an in vitro cellular model for oxidative stress, and cTBS treatment promoted the production of glutathione (GSH), the nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf2) and the mRNA expression of GSH synthesis-related genes to enhance antioxidant capacity in hippocampal tissues of SD mice. An Nrf2 inhibitor ML385 or a GSH synthesis inhibitor BSO reversed the alleviating effects of cTBS treatment on oxidative stress-associated damage of hippocampal tissues and cognitive impairment in SD model mice. Altogether, our study demonstrated that cTBS mitigates oxidative stress-associated inflammation and autophagy through activating the Nrf2-mediated GSH synthesis pathway, improving cognitive impairment in SD mice.

Chronic Pain-Related Cognitive Deficits: Preclinical Insights into Molecular, Cellular, and Circuit Mechanisms

Cognitive impairment is a common comorbidity of chronic pain, significantly disrupting patients' quality of life. Despite this comorbidity being clinically recognized, the underlying neuropathological mechanisms remain unclear. Recent preclinical studies have focused on the fundamental mechanisms underlying the coexistence of chronic pain and cognitive decline. Pain chronification is accompanied by structural and functional changes in the neural substrate of cognition. Based on the developments in electrophysiology and optogenetics/chemogenetics, we summarized the relevant neural circuits involved in pain-induced cognitive impairment, as well as changes in connectivity and function in brain regions. We then present the cellular and molecular alternations related to pain-induced cognitive impairment in preclinical studies, mainly including modifications in neuronal excitability and structure, synaptic plasticity, glial cells and cytokines, neurotransmitters and other neurochemicals, and the gut-brain axis. Finally, we also discussed the potential treatment strategies and future research directions.

Can Improving Postoperative Sleep Speed Up Surgical Recovery?

Sleep disturbance is common during recovery after surgical procedures and may have an important effect on mortality, and quality of life. Sleep restriction/deprivation, including decreased quantity and continuity, is common in patients who are patients and persons with acute and chronic illnesses. Age, gender, illness, primary sleep disorders, environment, and medical treatment factors are thought to influence sleep throughout the preoperative period, hospitalization, and recovery. Resulting sleep pattern disturbances include decreases in circadian patterning, continuity, duration, and perceived (subjective) sleep quality. This article synthesizes sleep disturbance in patients who have undergone surgery and highlights sleep strategies to improve faster surgical recovery.

The Effect of Low-Dose Dexmedetomidine on Perioperative Neurocognitive Dysfunction in Elderly Patients Undergoing Endoscopic Retrograde Cholangiopancreatography (ERCP): A Randomized, Controlled, Double-Blind Trial

Objective

This study investigates the effect of low-dose dexmedetomidine infusion on perioperative neurocognitive function in elderly patients undergoing endoscopic retrograde cholangiopancreatography (ERCP).

Patients and Methods

This double-blind trial enrolled 80 elderly ERCP patients randomized to receive dexmedetomidine (Group D) or placebo (Group S). Group D received dexmedetomidine at 0.4 μg·kg-1·h-1 starting 15 minutes before surgery until completion, along with propofol at 1.5 mg/kg for anesthesia. Group S received saline and propofol in a similar manner. Anesthesia was maintained with dexmedetomidine at 0.4 μg·kg-1·h-1 and propofol at 1-2 mg/kg during surgery. Cognitive function was assessed using the Mini-Mental State Examination (MMSE) preoperatively and on postoperative days 1, 3, and 5. Primary outcome was perioperative neurocognitive disorder (PND) incidence on day 5; secondary outcomes included changes in perioperative IL-6, cortisol, S100-β, hemodynamics, anesthesia parameters, postoperative pain, agitation scores, and adverse events.

Results

All 80 patients completed the trial. On postoperative day 5, the cumulative probability of PND incidence was significantly lower in Group D than in Group S (12.5% vs 35%, P=0.018). Group D also had lower levels of IL-6 (F=199.472, P<0.001), S100-β (F=2681.964, P<0.001), and cortisol (F=137.637, P<0.001). Propofol doses were lower in Group D (706.1 ± 202.4 vs 1003.3 ± 203.7, P<0.001), and bradycardia rates were higher (45% vs 15%, P=0.003), though atropine use did not significantly differ between groups. Group D showed greater stability in mean arterial pressure. Postoperative complications and adverse reactions were similar across groups.

Conclusion

Perioperative low-dose dexmedetomidine infusion with propofol in elderly ERCP patients ensures safe and effective monitored anesthesia care (MAC), reducing PND incidence by mitigating peripheral inflammation and stress responses. Long-term follow-up is needed to fully evaluate PND incidence.

Effects of Dexmedetomidine Added to Ropivacaine in Ultrasound-Guided Continuous Pericapsular Nerve Group Block Among Elderly Patients Undergoing Total Hip Arthroplasty

Total hip arthroplasty (THA) is a highly effective intervention for addressing hip joint issues, yet managing perioperative pain remains a significant challenge. In this study, we aimed to investigate the impact of supplementing ropivacaine with dexmedetomidine in ultrasound-guided continuous pericapsular nerve group block (PENGB) among elderly patients undergoing THA. We conducted a retrospective analysis involving 112 elderly patients who underwent THA. These patients were divided into two groups: the Control group, receiving ropivacaine alone, and the DEX group, receiving ropivacaine combined with dexmedetomidine. We evaluated various parameters including hemodynamic data, postoperative pain levels assessed using the Visual Analog Scale, cognitive status measured with the Montreal Cognitive Assessment, and serum markers (S100β and GFAP). Our findings revealed that the DEX group exhibited improved stability in blood pressure and oxygen saturation following surgery. Moreover, patients in the DEX group reported significantly lower levels of pain at 6 and 12 hours postsurgery, with a prolonged duration of pain relief. Furthermore, dexmedetomidine administration was associated with preserved cognitive function during the early postoperative period. Analysis of serum markers suggested potential cognitive protection conferred by the addition of dexmedetomidine. Overall, our study underscores the multifaceted benefits of incorporating dexmedetomidine into ropivacaine-based PENGB for elderly THA patients.

Propofol improves sleep deprivation-induced sleep structural and cognitive deficits via upregulating the BMAL1 expression and suppressing microglial M1 polarization

BACKGROUND

Sleep deprivation (SD) is a growing global health problem with many deleterious effects, such as cognitive impairment. Microglia activation-induced neuroinflammation may be an essential factor in this. Propofol has been shown to clear sleep debt after SD in rats. This study aims to evaluate the effects of propofol-induced sleep on ameliorating sleep quality impairment and cognitive decline after 48 h SD.

METHODS

Almost 8-12-week-old rats were placed in the SD system for 48 h of natural sleep or continuous SD. Afterwards, rats received propofol (20 mg·kg-1·h-1, 6 h) via the tail or slept naturally. The Morris water maze (MWM) and Y-maze test assessed spatial learning and memory abilities. Rat EEG/EMG monitored sleep. The expression of brain and muscle Arnt-like protein 1 (BMAL1), brain-derived neurotrophic factor (BDNF) in the hippocampus and BMAL1 in the hypothalamus were assessed by western blot. Enzyme-linked immunosorbent assay detected IL-6, IL-1β, arginase 1 (Arg1), and IL-10 levels in the hippocampus. Immunofluorescence was used to determine microglia expression as well as morphological changes.

RESULTS

Compared to the control group, the sleep-deprived rats showed poor cognitive performance on both the MWM test and the Y-maze test, accompanied by disturbances in sleep structure, including increased total sleep time, and increased time spent and delta power in non-rapid eye movement sleep. In addition, SD induces abnormal expression of the circadian rhythm protein BMAL1, activates microglia, and causes neuroinflammation and nerve damage. Propofol reversed these changes and saved sleep and cognitive impairment. Furthermore, propofol treatment significantly reduced hippocampal IL-1β and IL-6 levels, increased BDNF, Arg1, and IL-10 levels, and switched microglia surface markers from the inflammatory M1 type to the anti-inflammatory M2 type.

CONCLUSION

Propofol reduces SD-induced cognitive impairment and circadian rhythm disruption, possibly by lowering neuronal inflammation and switching the microglia phenotype from an M1 to an M2 activated state, thus exerting neuroprotective effects.

The influence of sleep disorders on perioperative neurocognitive disorders among the elderly: A narrative review

This review comprehensively assesses the epidemiology, interaction, and impact on patient outcomes of perioperative sleep disorders (SD) and perioperative neurocognitive disorders (PND) in the elderly. The incidence of SD and PND during the perioperative period in older adults is alarmingly high, with SD significantly contributing to the occurrence of postoperative delirium. However, the clinical evidence linking SD to PND remains insufficient, despite substantial preclinical data. Therefore, this study focuses on the underlying mechanisms between SD and PND, underscoring that potential mechanisms driving SD-induced PND include uncontrolled central nervous inflammation, blood-brain barrier disruption, circadian rhythm disturbances, glial cell dysfunction, neuronal and synaptic abnormalities, impaired central metabolic waste clearance, gut microbiome dysbiosis, hippocampal oxidative stress, and altered brain network connectivity. Additionally, the review also evaluates the effectiveness of various sleep interventions, both pharmacological and nonpharmacological, in mitigating PND. Strategies such as earplugs, eye masks, restoring circadian rhythms, physical exercise, noninvasive brain stimulation, dexmedetomidine, and melatonin receptor agonists have shown efficacy in reducing PND incidence. The impact of other sleep-improvement drugs (e.g., orexin receptor antagonists) and methods (e.g., cognitive-behavioral therapy for insomnia) on PND is still unclear. However, certain drugs used for treating SD (e.g., antidepressants and first-generation antihistamines) may potentially aggravate PND. By providing valuable insights and references, this review aimed to enhance the understanding and management of PND in older adults based on SD.

Sleep duration, chronotype, health and lifestyle factors affect cognition: a UK Biobank cross-sectional study

Objective

To explore the nuanced relationship between sleep patterns, chronotype, quality and the influence of health and lifestyle factors on cognitive performance.

Design setting participants

This cross-sectional analysis used ordinary least squares regression within the UK Biobank database, assessing 26 820 participants aged 53-86 years, categorised into two cohorts: Cohort 1 (10 067 participants, 56% female; completed all four cognitive tests of Fluid Intelligence/reasoning, Pairs Matching, Reaction Time and Prospective Memory) and Cohort 2 (16 753 participants, 56% female; completed only two cognitive assessments of Pairs Matching and Reaction Time).

Exposures

Participant's self-reported sleep duration, chronotype and quality. Cognitive function was assessed through standardised computerised tests. The analysis was adjusted for demographic and comorbidity covariates.

Main outcomes and measures

Cognitive performance scores were evaluated against sleep parameters and health and lifestyle factors including sex, age, vascular and cardiac conditions, diabetes, alcohol intake, smoking habits and body mass index.

Results

The regression highlighted a positive association between normal sleep duration (7-9 hours) and cognitive scores in Cohort 1 (β=0.0567, 95% CI 0.0284 to 0.0851), while extended sleep duration negatively impacted scores across both cohorts (Cohort 1: β=-0.188, 95% CI -0.2938 to -0.0822; Cohort 2: β=-0.2619, 95% CI -0.3755 to -0.1482). Chronotype distinctions, particularly intermediate and evening types, were linked to superior cognitive function. Gender, age, angina, high blood pressure, diabetes, alcohol intake and smoking emerged as significant cognitive influencers.

Conclusions and relevance

The study delineates a multifaceted and nuanced relationship between sleep variables, health and lifestyle factors in determining cognitive outcomes. These findings highlight the vital role of sleep quality on cognitive health.

Anatomical Substrates of Rapid Eye Movement Sleep Rebound in a Rodent Model of Post-sevoflurane Sleep Disruption

BACKGROUND

Previous research suggests that sevoflurane anesthesia may prevent the brain from accessing rapid eye movement (REM) sleep. If true, then patterns of neural activity observed in REM-on and REM-off neuronal populations during recovery from sevoflurane should resemble those seen after REM sleep deprivation. In this study, the authors hypothesized that, relative to controls, animals exposed to sevoflurane present with a distinct expression pattern of c-Fos, a marker of neuronal activation, in a cluster of nuclei classically associated with REM sleep, and that such expression in sevoflurane-exposed and REM sleep-deprived animals is largely similar.

METHODS

Adult rats and Targeted Recombination in Active Populations mice were implanted with electroencephalographic electrodes for sleep-wake recording and randomized to sevoflurane, REM deprivation, or control conditions. Conventional c-Fos immunohistochemistry and genetically tagged c-Fos labeling were used to quantify activated neurons in a group of REM-associated nuclei in the midbrain and basal forebrain.

RESULTS

REM sleep duration increased during recovery from sevoflurane anesthesia relative to controls (157.0 ± 24.8 min vs. 124.2 ± 27.8 min; P = 0.003) and temporally correlated with increased c-Fos expression in the sublaterodorsal nucleus, a region active during REM sleep (176.0 ± 36.6 cells vs. 58.8 ± 8.7; P = 0.014), and decreased c-Fos expression in the ventrolateral periaqueductal gray, a region that is inactive during REM sleep (34.8 ± 5.3 cells vs. 136.2 ± 19.6; P = 0.001). Fos changes similar to those seen in sevoflurane-exposed mice were observed in REM-deprived animals relative to controls (sublaterodorsal nucleus: 85.0 ± 15.5 cells vs. 23.0 ± 1.2, P = 0.004; ventrolateral periaqueductal gray: 652.8 ± 71.7 cells vs. 889.3 ± 66.8, P = 0.042).

CONCLUSIONS

In rodents recovering from sevoflurane, REM-on and REM-off neuronal activity maps closely resemble those of REM sleep-deprived animals. These findings provide new evidence in support of the idea that sevoflurane does not substitute for endogenous REM sleep.

EDITOR’S PERSPECTIVE

Activation of LXRs alleviates neuropathic pain-induced cognitive dysfunction by modulation of microglia polarization and synaptic plasticity via PI3K/AKT pathway

OBJECTIVE

Cognitive dysfunction is a common comorbidity in patients with chronic pain. Activation of Liver X receptors (LXRs) plays a potential role in improving cognitive disorders in central nervous diseases. In this study, we investigated the role of LXRs in cognitive deficits induced by neuropathic pain.

METHODS

We established the spared nerve injury (SNI) model to investigate pain-induced memory dysfunction. Pharmacological activation of LXRs with T0901317 or inhibition with GSK2033 was applied. PI3K inhibitor LY294002 was administered to explore the underlying mechanism of LXRs. Changes in neuroinflammation, microglia polarization, and synaptic plasticity were assessed using biochemical technologies.

RESULTS

We found that SNI-induced cognitive impairment was associated with reduced LXRβ expression, increased M1-phenotype microglia, decreased synaptic proteins, and inhibition of PI3K/AKT signaling pathway in the hippocampus. Activation of LXRs using T0901317 effectively alleviated SNI-induced cognitive impairment. Additionally, T0901317 promoted the polarization of microglia from M1 to M2, reduced pro-inflammatory cytokines, and upregulated synaptic proteins in the hippocampus. However, administration of GSK2033 or LY294002 abolished these protective effects of T0901317 in SNI mice.

CONCLUSIONS

LXRs activation alleviates neuropathic pain-induced cognitive impairment by modulating microglia polarization, neuroinflammation, and synaptic plasticity, at least partly via activation of PI3K/AKT signaling in the hippocampus. LXRs may be promising targets for addressing pain-related cognitive deficits.

Microglia facilitate and stabilize the response to general anesthesia via modulating the neuronal network in a brain region-specific manner

General anesthesia leads to a loss of consciousness and an unrousable state in patients. Although general anesthetics are widely used in clinical practice, their underlying mechanisms remain elusive. The potential involvement of nonneuronal cells is unknown. Microglia are important immune cells in the central nervous system (CNS) that play critical roles in CNS function and dysfunction. We unintentionally observed delayed anesthesia induction and early anesthesia emergence in microglia-depleted mice. We found that microglial depletion differentially regulates neuronal activities by suppressing the neuronal network of anesthesia-activated brain regions and activating emergence-activated brain regions. Thus, microglia facilitate and stabilize the anesthesia status. This influence is not mediated by dendritic spine plasticity. Instead, it relies on the activation of microglial P2Y12 and subsequent calcium influx, which facilitates the general anesthesia response. Together, we elucidate the regulatory role of microglia in general anesthesia, extending our knowledge of how nonneuronal cells modulate neuronal activities.

Dexmedetomidine compared to low-dose ketamine better protected not only the brain but also the lungs in acute ischemic stroke

BACKGROUND

Dexmedetomidine (DEX) and low-dose ketamine (KET) present neuroprotective effects in acute ischemic stroke (AIS); however, to date, no studies have evaluated which has better protective effects not only on the brain but also lungs in AIS.

METHODS

AIS-induced Wistar rats (390 ± 30 g) were randomized after 24-h, receiving dexmedetomidine (STROKE-DEX, n = 10) or low-dose S(+)-ketamine (STROKE-KET, n = 10). After 1-h protective ventilation, perilesional brain tissue and lungs were removed for histologic and molecular biology analysis. STROKE animals (n = 5), receiving sodium thiopental but not ventilated, had brain and lungs removed for molecular biology analysis. Effects of DEX and KET mean plasma concentrations on alveolar macrophages, neutrophils, and lung endothelial cells, extracted primarily 24-h after AIS, were evaluated.

RESULTS

In perilesional brain tissue, apoptosis did not differ between groups. In STROKE-DEX, compared to STROKE-KET, tumor necrosis factor (TNF)-α and vascular cell adhesion molecule-1 (VCAM-1) expressions were reduced, but no changes in nuclear factor erythroid 2-related factor-2 (Nrf2) and super oxide dismutase (SOD)-1 were observed. In lungs, TNF-α and VCAM-1 were reduced, whereas Nrf2 and SOD-1 were increased in STROKE-DEX. In alveolar macrophages, TNF-α and inducible nitric oxide synthase (M1 macrophage phenotype) were lower and arginase and transforming growth factor-β (M2 macrophage phenotype) higher in STROKE-DEX. In lung neutrophils, CXC chemokine receptors (CXCR2 and CXCR4) were higher in STROKE-DEX. In lung endothelial cells, E-selectin and VCAM-1 were lower in STROKE-DEX.

CONCLUSIONS

In the current AIS model, dexmedetomidine compared to low-dose ketamine reduced inflammation and endothelial cell damage in both brain and lung, suggesting greater protection.