Does Dexmedetomidine Ameliorate Postoperative Cognitive Dysfunction? A Brief Review of the Recent Literature

Dexmedetomidine Improves Long-term Neurological Outcomes by Promoting Oligodendrocyte Genesis and Myelination in Neonatal Rats Following Hypoxic-ischemic Brain Injury

Neonatal hypoxic-ischemic brain injury (HIBI) can lead to white matter damage, which significantly contributes to cognitive dysfunction, emotional disorders, and sensorimotor impairments. Although dexmedetomidine enhances neurobehavioral outcomes, its impact on oligodendrocyte genesis and myelination following hypoxic-ischemic events, as well as the underlying mechanisms, remain poorly understood. Dexmedetomidine was administered 15 min post-HIBI. We assessed neurobehavioral deficits using various tests: surface righting, negative geotaxis, forelimb grip strength, cliff avoidance, sensory reflexes, novel object recognition, T-maze, and three-chamber social interaction. We also investigated the relationship between myelination and neurobehavioral outcomes. Measurements included oligodendrocyte precursor cell (OPC) proliferation and survival 24 h post-injury, early myelination, and oligodendrocyte differentiation by postnatal day 14. Furthermore, we evaluated microglial activation towards the M2 phenotype and the extent of neuroinflammation during the acute phase. Dexmedetomidine significantly ameliorated long-term neurological deficits caused by HIBI. Pearson linear regression analysis revealed a strong correlation between long-term neurological outcomes and myelin maturity. The treatment notably mitigated the long-term deterioration of myelin formation and maturation following HIBI. This protective effect was primarily due to enhanced OPC proliferation and survival post-HIBI during the acute phase and, to a lesser extent, to the modulation of microglial activity towards the M2 phenotype and a reduction in neuroinflammation. Dexmedetomidine offers substantial protection against long-term neurobehavioral disabilities induced by HIBI, primarily by revitalizing the impaired survival and maturation of oligodendrocyte progenitor cells and promoting myelination.

Perioperative neurocognitive dysfunction and role of dexmedetomidine in radical colon cancer surgery in elderly patients

This article explored the application of dexmedetomidine (Dex), a highly selective alpha-2 agonist, in managing postoperative cognitive dysfunction (POCD) in elderly patients undergoing radical colon cancer surgery. Aging is associated with a progressive decline in physiological functions and an increased risk of adverse surgical outcomes, including POCD, which encompasses many neurocognitive disorders that manifest during the perioperative period. The aging population is at a higher risk for POCD, which can lead to prolonged hospital stays, delayed recovery, and increased healthcare costs. Dex has neuroprotective, opioid-sparing, and sympatholytic properties, which reduces the incidence and severity of POCD. Dex was introduced for sedation in patients receiving mechanical ventilation but has since been adopted in anesthesia due to its multifaceted benefits. Its application extends to sedation, analgesia, maintenance of anesthesia, and controlling delirium. Its neuroprotective and anti-inflammatory effects have been explored in managing POCD. This article discussed the broad range of patient and procedure-related risk factors for POCD. Early identification and intervention are crucial to prevent the progression of POCD, which can have severe physical, psychological, and economic consequences. The article underscored the importance of a multidisciplinary approach in managing POCD, involving the optimization of comorbidities, depth of anesthesia monitoring, hemodynamic stability, and cerebral oxygenation monitoring.

Amyloid beta-induced mitochondrial dysfunction and endothelial permeability in cerebral microvascular endothelial cells: The protective role of dexmedetomidine

Postoperative cognitive dysfunction (POCD) is a common complication in patients who undergo anesthesia in different types of surgeries. Emerging evidence implicates elevated beta-amyloid (Aβ) in the pathogenesis of POCD. Meanwhile, Dexmedetomidine (DEX) has recently shown promise in reducing POCD incidence. This study aimed to elucidate the role of Aβ in inducing endothelial permeability in cerebral microvascular endothelial cells and the underlying mechanisms and testing the effects of DEX. We demonstrated that Aβ1-42, the prevalent Aβ form related to POCD, is cytotoxic to HBMECs, increasing transendothelial permeability and inducing mitochondrial dysfunction, as evidenced by elevated mitochondrial reactive oxygen species (ROS) and decreased ATP production and mitochondrial membrane potential. Furthermore, Aβ1-42 was shown to inhibit Sirt3, exacerbating mitochondrial dysfunction. Conversely, DEX was found to prevent Aβ1-42-induced mitochondrial dysfunction and permeability increases and preserved tight junction proteins in HBMECs.These findings suggest that DEX, as a Sirt3 activator, may offer a pharmacological strategy to mitigate Aβ1-42-related cerebral microvascular endothelial cell dysfunction and preserve cognitive function post-surgery.

Postoperative cognitive dysfunction: Review of pathophysiology, diagnostics and preventive strategies

Postoperative cognitive impairment is a common disorder after major surgery. Advances in medicine and treatment have resulted in an increasingly ageing population undergoing major surgical procedures. Since age is the most important risk factor for postoperative cognitive decline, it is not surprising that impairment of cognitive functions after surgery was recorded in almost a third of elderly patients. Postoperative cognitive dysfunction is part of the spectrum of postoperative cognitive impairment and researchers often confuse it with postoperative delirium and delayed neurocognitive recovery. This is the cause of great differences in the results of research that is focused on the incidence and possible prevention of postoperative cognitive dysfunction. In this review, we focused on current recommendations for a uniform nomenclature of postoperative cognitive impairment and diagnosis of postoperative cognitive dysfunction, the presumed pathophysiology of postoperative cognitive dysfunction and recommendations for its treatment and possible prevention strategies.

Sodium Butyrate Ameliorates Postoperative Delirium by Regulating Gut Microbiota Dysbiosis to Inhibit Astrocyte Activation in Aged Mice

Postoperative delirium (POD) is a common complication in elderly surgical patients, with limited targeted interventions due to incomplete understanding of its pathophysiological mechanisms. Central nervous system (CNS) inflammation, involving glial cell activation, particularly astrocytes, is considered crucial in POD development. Butyrate, a four-carbon fatty acid, has shown protective effects in CNS diseases, but its potential in mitigating POD remains unclear. This study aimed to investigate the impact of sodium butyrate on POD in aged mice. Behavioral tests, including open field, Y maze, and food burying tests, demonstrated that sodium butyrate preconditioning ameliorated laparotomy-induced delirium in aged mice. Pre-treatment with sodium butyrate inhibited astrocyte activation in the hippocampus, reduced interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) expression levels, and protected hippocampal neurons. Furthermore, the study revealed a connection between gut microbiota regulation and central neuroprotective effects mediated by astrocyte activation inhibition. Sodium butyrate improved the intestinal morphological barrier by rebalancing gut microbiota, inhibiting Proteobacteria and Actinobacteria, reducing Allobaculum and Bacteroides abundance, and increasing Oscillospira abundance. This regulation decreased gut permeability, limiting the entry of toxic substances into the bloodstream, thereby reducing inflammation spread and astrocyte overactivation, leading to central anti-inflammatory effects. In conclusion, sodium butyrate may ameliorate POD by inhibiting astrocyte-mediated neuroinflammation through gut microbiota rebalancing.

Dexmedetomidine enhances Mitophagy via PINK1 to alleviate hippocampal neuronal Pyroptosis and improve postoperative cognitive dysfunction in elderly rat

Postoperative cognitive dysfunction (POCD) is a common complication in elderly surgical patients, significantly affecting their quality of life. Dexmedetomidine (Dex), an anesthetic, has shown promise in alleviating POCD, but its underlying mechanism remains unclear. This study aims to explore how Dex improves POCD in aged rats by targeting the PINK1-mediated mitochondrial autophagy pathway, reducing caspase-1/11-GSDMD-induced hippocampal neuronal pyroptosis. Transcriptome sequencing identified 300 differentially expressed genes enriched in the mitochondrial autophagy pathway in Dex-treated POCD rat hippocampal tissue, with Pink1 as a key candidate. In a POCD rat model, Dex treatment upregulated hippocampal PINK1 expression. In vitro experiments using H19-7 rat hippocampal neurons revealed that Dex enhanced mitochondrial autophagy and suppressed neuronal pyroptosis by upregulating PINK1. Further mechanistic validation demonstrated that Dex activated PINK1-mediated mitochondrial autophagy, inhibiting caspase-1/11-GSDMD-induced neuronal pyroptosis. In vivo experiments confirmed Dex's ability to reduce caspase-1/11-GSDMD-dependent hippocampal neuronal pyroptosis and improve postoperative cognitive function in aged rats. Dexmedetomidine improves postoperative cognitive dysfunction in elderly rats by enhancing mitochondrial autophagy via PINK1 upregulation, mitigating caspase-1/11-GSDMD-induced neuronal pyroptosis.

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.

The effects of dexmedetomidine on postoperative cognitive dysfunction in rats with bone fractures undergoing open reduction

OBJECTIVE

To investigate the effects of dexmedetomidine on the cognitive dysfunction of aged rats after open tibia fracture surgery and the expression of inflammatory cytokines in the hippocampus.

METHODS

A total of 45 aged healthy male Sprague Dawley rats were divided into control group, sham group, and dexmedetomidine group. The open tibia fracture surgery rat model was established, and dexmedetomidine was intraperitoneally injected before operation. The cognitive function of aged rats was examined by Morris Water-Maze Test, open field experiment, and passive avoidance memory test. The expression levels of IL-6, IL-1β, and TNF-α in the hippocampus were examined by enzyme-linked immunosorbent assay (ELISA).

RESULTS

The escape latency over 5 continuous days in the dexmedetomidine group was significantly shorter than that in the control group (all P<0.05). The number of swimming times and the percentage of swimming time in the dexmedetomidine group were significantly higher and longer than those in the control group (all P<0.05). Moreover, rats in the dexmedetomidine group exhibited shorter time of stay at the central square and higher number of standing times in comparison with the control group (all P<0.05). Compared with the control group, dexmedetomidine intraperitoneally injected before surgery significantly inhibited the expression levels of IL-6, IL-1β, and TNF-α in the hippocampus (all P<0.05).

CONCLUSION

Dexmedetomidine could significantly relieve the postoperative cognitive dysfunction in aged rats. The mechanism may be associated with the decreased inflammatory cytokines in the hippocampus.

Personalized anesthesia and precision medicine: a comprehensive review of genetic factors, artificial intelligence, and patient-specific factors

Precision medicine, characterized by the personalized integration of a patient's genetic blueprint and clinical history, represents a dynamic paradigm in healthcare evolution. The emerging field of personalized anesthesia is at the intersection of genetics and anesthesiology, where anesthetic care will be tailored to an individual's genetic make-up, comorbidities and patient-specific factors. Genomics and biomarkers can provide more accurate anesthetic protocols, while artificial intelligence can simplify anesthetic procedures and reduce anesthetic risks, and real-time monitoring tools can improve perioperative safety and efficacy. The aim of this paper is to present and summarize the applications of these related fields in anesthesiology by reviewing them, exploring the potential of advanced technologies in the implementation and development of personalized anesthesia, realizing the future integration of new technologies into clinical practice, and promoting multidisciplinary collaboration between anesthesiology and disciplines such as genomics and artificial intelligence.

Dexmedetomidine alleviates hippocampal neuronal loss and cognitive decline in rats undergoing open surgery under sevoflurane anaesthesia by suppressing CCAAT/enhancer-binding protein beta

Dexmedetomidine (Dex) may exert neuroprotective effects by attenuating inflammatory responses. However, whether Dex specifically improves postoperative cognitive dysfunction (POCD) by inhibiting microglial inflammation through what pathway remains unclear. In this study, the POCD model was constructed by performing open surgery after 3 h of continuous inhalation of 3% sevoflurane to rats, which were intraperitoneally injected with 25 μg/kg Dex .5 h before anaesthesia. The results displayed that Dex intervention decreased rat escape latency, maintained swimming speed and increased the number of times rats crossed the platform and the time spent in the target quadrant. Furthermore, the rat neuronal injury was restored, alleviated POCD modelling-induced rat hippocampal microglial activation and inhibited microglial M1 type polarization. Besides, we administered Dex injection and/or CCAAT/enhancer-binding protein beta (CEBPB) knockdown on the basis of sevoflurane exposure and open surgery and found that CEBPB was knocked down, resulting in the inability of Dex to function, which confirmed CEBPB as a target for Dex treatment. To sum up, Dex improved POCD by considering CEBPB as a drug target to activate the c-Jun N-terminal kinase (JNK)/p-38 signaling pathway, inhibiting microglial M1 polarization-mediated inflammation in the central nervous system.

Determination of the effective dose of dexmedetomidine to achieve loss of consciousness during anesthesia induction

Background

Dexmedetomidine (DEX) is a sedative with greater preservation of cognitive function, reduced respiratory depression, and improved patient arousability. This study was designed to investigate the performance of DEX during anesthesia induction and to establish an effective DEX induction strategy, which could be valuable for multiple clinical conditions.

Methods

Patients undergoing abdominal surgery were involved in this dose-finding trial. Dixon's up-and-down sequential method was employed to determine the effective dose of DEX to achieve the state of "loss of consciousness", and an effective induction strategy was established with continuous infusion of DEX and remifentanil. The effects of DEX on hemodynamics, respiratory state, EEG, and anesthetic depth were monitored and analyzed.

Results

Through the strategy mentioned, the depth of surgical anesthesia was successfully achieved by DEX-led anesthesia induction. The ED50 and ED95 of the initial infusion rate of DEX were 0.115 and 0.200 μg/kg/min, respectively, and the mean induction time was 18.3 min. The ED50 and ED95 of DEX to achieve the state of "loss of consciousness" were 2.899 (95% CI: 2.703-3.115) and 5.001 (95% CI: 4.544-5.700) μg/kg, respectively. The mean PSI on the loss of consciousness was 42.8 among the patients. During anesthesia induction, the hemodynamics including BP and HR were stable, and the EEG monitor showed decreased α and β powers and increased θ and δ in the frontal and pre-frontal cortices of the brain.

Conclusion

This study indicated that continuous infusion of combined DEX and remifentanil could be an effective strategy for anesthesia induction. The EEG during the induction was similar to the physiological sleep process.

Heterogeneous nuclear ribonucleoprotein A2/B1 as a novel biomarker in elderly patients for the prediction of postoperative neurocognitive dysfunction: A prospective nested case-control study

Background and objective

Postoperative neurocognitive dysfunction (PND) occurs in up to 54% of older patients, giving rise to the heavy psychological and economic burdens to patients and society. To date, the development of PND biomarkers remains a challenge. Heterogeneous nuclear ribonucleoprotein A2/B1 (hnRNPA2/B1) is an RNA-binding protein whose prion-like structure is prone to mutation and hence leads to neurodegenerative diseases, but its expression changes in PND remains unclear. Here, we detect the preoperative hnRNPA2/B1 level in patients with PND, and to explore its value in the prediction and diagnosis of PND.

Methods

The study included 161 elderly patients undergoing lumbar decompression and fusion in Nankai University Affinity the Third Central Hospital from September 2021 to July 2022. Neuropsychological and psychometric evaluations were performed before surgery, 1 week and 3 months after surgery to diagnose the occurrence of PND, then the peripheral blood was collected from patients before induction of anesthesia. The concentration in plasma of hnRNPA2/B1 and amyloid-β 42 were determined by enzyme-linked immunosorbent assay. The median fluorescence intensity and mRNA levels of hnRNPA2/B1 in peripheral blood mononuclear cells was detected by indirect intracellular staining flow cytometry and quantitative real-time PCR, respectively.

Results

The preoperative hnRNPA2/B1 level in patients with PND was higher both in short-time and long-time follow-up. We found significantly higher concentrations of hnRNPA2/B1 in PND at 7 days after surgery (median, 72.26 pg/mL vs. 54.95 pg/mL, p = 0.022) compared with patients without PND, and so as 3 months after surgery (median, 102.93 pg/mL vs. 56.38 pg/mL, p = 0.012). The area under the curve (AUC) was predicted to be 0.686 at 7 days after surgery and 0.735 at 3 months. In addition, when combining several clinical information, the diagnostic efficiency of hnRNPA2/B1 for PND could further increase (AUC, 0.707 at 7 days, 0.808 at 3 months).

Conclusion

Based on the findings reported here, hnRNPA2/B1 may serve as a new and powerful predictive biomarker to identify elderly patients with PND.

Epigenetic Mechanisms of Postoperative Cognitive Impairment Induced by Anesthesia and Neuroinflammation

Cognitive impairment after surgery is a common problem, affects mainly the elderly, and can be divided into postoperative delirium and postoperative cognitive dysfunction. Both phenomena are accompanied by neuroinflammation; however, the precise molecular mechanisms underlying cognitive impairment after anesthesia are not yet fully understood. Anesthesiological drugs can have a longer-term influence on protein transcription, thus, epigenetics is a possible mechanism that impacts on cognitive function. Epigenetic mechanisms may be responsible for long-lasting effects and may implicate novel therapeutic approaches. Hence, we here summarize the existing literature connecting postoperative cognitive impairment to anesthesia. It becomes clear that anesthetics alter the expression of DNA and histone modifying enzymes, which, in turn, affect epigenetic markers, such as methylation, histone acetylation and histone methylation on inflammatory genes (e.g., TNF-alpha, IL-6 or IL1 beta) and genes which are responsible for neuronal development (such as brain-derived neurotrophic factor). Neuroinflammation is generally increased after anesthesia and neuronal growth decreased. All these changes can induce cognitive impairment. The inhibition of histone deacetylase especially alleviates cognitive impairment after surgery and might be a novel therapeutic option for treatment. However, further research with human subjects is necessary because most findings are from animal models.

Dexmedetomidine Ameliorated Cognitive Dysfunction Induced by Intestinal Ischemia Reperfusion in Mice with Possible Relation to the Anti-inflammatory Effect Through the Locus Coeruleus Norepinephrine System

Cognitive impairment is a common central nervous system complication that occurs following surgery or organs damage outside the nervous system. Neuroinflammation plays a key role in the molecular mechanisms of cognitive impairment. Dexmedetomidine alleviates neuroinflammation and reduces cognitive dysfunction incidence; however, the mechanism by which dexmedetomidine alleviates cognitive dysfunction remains unclear. This study evaluated the effect of dexmedetomidine on attenuation of early cognitive impairment induced by intestinal ischemia–reperfusion in mice and examined whether the locus coeruleus norepinephrine (LCNE) system participates in the anti-inflammatory effect of dexmedetomidine. The superior mesenteric artery was clamped for 45 min to induce intestinal ischemia reperfusion injury. Dexmedetomidine alone or combined with DSP-4, a selective locus coeruleus noradrenergic neurotoxin, was used for pretreatment. Postoperative cognition was assessed using the Morris water maze. Serum and hippocampal levels of IL-1β, TNF-α, norepinephrine (NE), and malondialdehyde (MDA) were assessed by enzyme-linked immunosorbent assay. Immunofluorescence, immunohistochemistry, and hematoxylin and eosin staining were used to evaluate the expression of tyrosine hydroxylase (TH) in the locus coeruleus, hippocampal microglia, and intestinal injury. Pretreatment with dexmedetomidine alleviated intestinal injury and decreased the serum and hippocampal levels of NE, IL-1β, TNF-α, and MDA at 24 h after intestinal ischemia reperfusion, decreased TH-positive neurons in the locus coeruleus, and ameliorated cognitive impairment. Similarly, DSP-4 pre-treatment alleviated neuroinflammation and improved cognitive function. Furthermore, α2-adrenergic receptor antagonist atipamezole or yohimbine administration diminished the neuroprotective effects and improved cognitive function with dexmedetomidine. Therefore, dexmedetomidine attenuated early cognitive dysfunction induced by intestinal ischemia–reperfusion injury in mice, which may be related to its anti-inflammatory effects through the LCNE system.

Meta-Analysis of the Correlation between Postoperative Cognitive Dysfunction and Intraoperative Cerebral Oxygen Saturation

Objective

This study is aimed at performing a meta-analysis for discussing the association between postoperative cognitive dysfunction (POCD) and cerebral cortical oxygen saturation after surgery (rSO2).

Method

Search common English databases such as Cochrane Library, PubMed, and Embase databases to evaluate the quality of all references. According to the normalized mean difference (SMD) and 95% confidence interval calculated by the revman5 software, the correlation between reported POCD and rSO2 was evaluated. The retrieval time is up to February 1, 2021.

Results

A total of 7 randomized controlled trials and 564 POCD patients were included in the study, with follow-up duration of 1-12 months. All patients were divided into control and operation subgroups. In the subgroup analysis of elderly patients, abdominal surgery, and orthopedic surgery, the mean intraoperative cerebral oxygen saturation of patients with POCD was significantly lower than those of patients without POCD (I 2 = 55%, SMD = -0.57).

Conclusion

Lower intraoperativersO2 was associated with reduced incidence of neurological complications and renal alure as well as the length of stay in the intensive care unit and the total hospital stay.

Dexmedetomidine attenuates perioperative neurocognitive disorders by suppressing hippocampal neuroinflammation and HMGB1/RAGE/NF-κB signaling pathway

Surgical trauma can induce an inflammatory response in the central nervous system. Neuroinflammation is a crucial pathological mechanism of perioperative neurocognitive disorders (PND). Dexmedetomidine (Dex) is an alpha (α)-2 adrenoceptor agonist that is widely used in the perioperative period. Previous studies have shown that Dex has neuroprotection in various nerve injury models, but its role in PND remains unclear. Our study aimed to observe the neuroprotective effect of Dex pretreatment on postoperative cognitive change and explore the effects of hippocampal neuroinflammation, microglial polarization and HMGB1/RAGE/NF-κB signaling pathway involved in Dex on PND in rats. Rats were pretreated with Dex alone or in combination with yohimbine (α-2 adrenoceptor antagonist) before surgery. Behavioral tests results showed that Dex ameliorated surgery-induced cognitive impairment in rats. Nissl, immunohistochemistry and TUNEL-NeuN staining results indicated that Dex reduced hippocampus damage and neuronal apoptosis caused by surgery. Dex preconditioning reduced the expression of the proinflammatory cytokines IL-1β, TNF-α and IL-6 in hippocampus. Immunohistochemical and immunofluorescence results showed that Dex preconditioning inhibited the activation of glial cells induced by surgery. Western blot analysis showed that Dex preconditioning downregulated the expression of M1 phenotype markers (CD86 and iNOS), HMGB1, RAGE and nuclear NF-κB and upregulated the expression of M2 phenotype markers (Arginase 1 and CD206) and cytoplasmic NF-κB. Yohimbine could inhibit the neuroprotective effect of Dex. These results indicated that Dex pretreatment could improve postoperative short-term cognitive impairment, and the neuroprotective mechanism may involve the suppression of hippocampal neuroinflammation, regulation of M1/M2 polarization, and inhibition of HMGB1/RAGE/NF-κB signal transduction.

Effect of Dexmedetomidine on Early Postoperative Cognitive Function in Patients Undergoing Arthroscopic Shoulder Surgery in Beach Chair Position: A Randomized Double-Blind Study

This study sought to determine whether intraoperative dexmedetomidine infusion might reduce the incidence of postoperative cognitive dysfunction (POCD) and alleviate the neuroinflammatory response in patients who have undergone arthroscopic shoulder surgery. A total of 80 patients over 60 years of age who had undergone arthroscopic shoulder surgery in the beach chair position were randomly allocated to either the dexmedetomidine group (Group D) or the control group (Group C). Dexmedetomidine (0.6 μg/kg/h) or a comparable amount of normal saline was infused into each group during the surgery. The early incidence of POCD was assessed by comparing cognitive tests on the day before and 1 d after surgery. The neuroinflammatory response with the S100 calcium-binding protein B (S100β) assay was compared prior to anesthetic induction and 1 h following surgery. The incidence of POCD was comparable between groups D (n = 9, 22.5%) and C (n = 9, 23.7%) (p = 0.901). However, the results of the cognitive test revealed a significant difference between the groups after surgery (p = 0.004). Although the S100β levels measured at the end of surgery were significantly higher than those at baseline in both groups (p < 0.001), there was no difference between the groups after the surgery (p = 0.236). Our results suggest that intraoperative dexmedetomidine infusion neither reduce the incidence of early POCD nor alleviated the neuroinflammatory response in patients undergoing arthroscopic shoulder surgery.

The Anesthetic Effect and Safety of Dexmedetomidine in Cesarean Section: A Meta-Analysis

Objective. To evaluate the anesthetic effect and safety of dexmedetomidine in cesarean section. Methods. The Cochrane Library, EMBASE, and PubMed databases (established until September 2020) were searched by computer. Two authors independently screened and extracted literature related to the application of dexmedetomidine in the cesarean section according to inclusion and exclusion criteria. The control group received either subarachnoid block (lumbar anesthesia) or combined lumbar anesthesia and epidural anesthesia (combined lumbar epidural anesthesia) with bupivacaine or combined bupivacaine and fentanyl. The observation group was additionally given dexmedetomidine based on the control group, to analyze the anesthetic effect and safety of dexmedetomidine in cesarean section. Results. A total of 580 cesarean delivery women were included in 8 studies, and the results showed that the peak time of sensory block in the observation group was shorter than that in the control group (standard mean $\text{difference}=-0.28$ ; 95% confidence interval: -0.48, -0.08; $P=0.006$ ), sensory block lasted longer than that in the control group (standard mean $\text{difference}=1.49$ ; 95% confidence interval: 1.21, 1.78; $P<0.00001$ ), the sedation rate was higher than that in the control group, the onset of the first postoperative pain was significantly delayed compared with that in the control group, and the incidence of postoperative pain, nausea and vomiting, postoperative chills, and fever was lower than that in the control group ( $P<0.05$ ). Conclusion. Dexmedetomidine combined with lumbar anesthesia or combined lumbar epidural anesthesia for women in cesarean section has more clinical benefits and better safety.

Analgesic and Sedative Effects of Different Doses of Dexmedetomidine Combined with Butorphanol in Continuous Analgesia after a Cesarean Section

Objective

The present study is designed to study the analgesic and sedative effect of different doses of dexmedetomidine combined with butorphanol in continuous analgesia after a cesarean section.

Methods

A total of 60 puerperae undergoing a cesarean section recruited from a single center were divided into three groups according to the postoperative continuous analgesia protocol: control group (100 mL of normal saline containing 10 µg/kg fentanyl and 0.25 mg of palonosetron, 2 mL/h for continuous analgesia for 48 h), DB1 group (100 mL of normal saline containing 1.0 µg/kg dexmedetomidine, 4 mg of butorphanol, 10 µg/kg fentanyl, and 0.25 mg of palonosetron, 2 mL/h for continuous analgesia for 48 h), and DB2 group (100 mL normal saline containing 2.0 µg/kg dexmedetomidine, 4 mg of butorphanol, 10 µg/kg fentanyl, and 0.25 mg of palonosetron, 2 mL/h for continuous analgesia for 48 h). We compared the blood pressure, heart rate, oxygen saturation, VAS score, Ramsay score, and adverse reactions of puerperae among the three groups after surgery.

Results

The baseline data all have no significant difference in the three groups (p > 0.05). Compared with those in the control group, the systolic blood pressure, diastolic blood pressure, heart rate, and VAS score of the puerperae in the DB1 group and DB2 group were significantly decreased at 6, 24, and 48 h (P < 0.05), while the Ramsay scores of the puerperae in DB1 group and DB2 group were significantly increased at 6, 24, and 48 h (p < 0.05). At the same time, the systolic blood pressure, diastolic blood pressure, heart rate, and VAS score of the puerperae in the DB2 group were significantly lower than those in the DB1 group (P < 0.05), while the Ramsay scores of the puerperae in DB2 group were significantly higher than those in the DB1 group (P < 0.05). Also, there is no significant difference in oxygen saturation and adverse reactions of puerperae among the three groups after surgery (p > 0.05).

Conclusion

Dexmedetomidine combined with butorphanol can improve the analgesic and sedative effects in continuous analgesia after a cesarean section, and the analgesic and sedative effects of dexmedetomidine in the high-dose group are better than those in the low-dose group.

Gut-Brain Axis: Possible Role of Gut Microbiota in Perioperative Neurocognitive Disorders

Aging is becoming a severe social phenomenon globally, and the improvements in health care and increased health awareness among the elderly have led to a dramatic increase in the number of surgical procedures. Because of the degenerative changes in the brain structure and function in the elderly, the incidence of perioperative neurocognitive disorders (PND) is much higher in elderly patients than in young people following anesthesia/surgery. PND is attracting more and more attention, though the exact mechanisms remain unknown. A growing body of evidence has shown that the gut microbiota is likely involved. Recent studies have indicated that the gut microbiota may affect postoperative cognitive function via the gut-brain axis. Nonetheless, understanding of the mechanistic associations between the gut microbiota and the brain during PND progression remains very limited. In this review, we begin by providing an overview of the latest progress concerning the gut-brain axis and PND, and then we summarize the influence of perioperative factors on the gut microbiota. Next, we review the literature on the relationship between gut microbiota and PND and discuss how gut microbiota affects cognitive function during the perioperative period. Finally, we explore effective early interventions for PND to provide new ideas for related clinical research.

Role of Dexmedetomidine in Early POCD in Patients Undergoing Thoracic Surgery

Objective

To evaluate whether a low-dose perioperative infusion of Dex reduces early POCD.

Design

This study was a double-blind, randomized, placebo-controlled trial that randomly assigned patients to Dex or saline placebo infused during surgery and patient-controlled intravenous analgesia (PCIA) infusion. Patients were assessed for postoperative cognitive decline. Interventions. Dex was infused at a loading dose of 0.5 μg/kg intravenously (15 min after entering the operation room) followed by a continuous infusion at a rate of 0.5 μg/kg/h until one-lung ventilation or artificial pneumothorax ended. Patients in the Dex group received regular PCIA pump with additional dose of Dex (200 μg).

Results

In total, 126 patients were randomized, and 102 patients were involved in the result analysis. The incidence of POCD was 36.54% (19/52) in the Dex group and 32.00% (16/50) in the normal saline (NS) group, with no statistic difference. No significant difference was observed between the two groups in terms of Telephone Interview for Cognitive Status-Modified (TICS-m) scores at different times. However, the TICS-m score at 7 days after surgery was significantly lower than that at 30 days in 102 patients (32.93 ± 0.42 vs. 33.92 ± 0.47, P = 0.03). The visual analogue scale scores in the Dex group were significantly lower than those in the NS group 1 day postoperation at rest and activity (2.00 [1.00-3.00] vs. 3.00 [2.00-4.00], P < 0.01; 4.00 [3.00-5.00] vs. 5.00 [4.00-6.00], P < 0.05, respectively). Patients receiving Dex or NS had no statistical difference in activities of daily living (ADLs) scores at 7 and 30 days after surgery, but the ADL score at 30 days after surgery showed a significant reduction compared with that at 7 days (P < 0.01). Patients in the Dex group had a shorter hospital length of stay (15.26 ± 3.77 vs. 17.69 ± 5.09, P = 0.02) and less expenses (52458.71 ± 10649.30 vs. 57269.03 ± 9269.98, P = 0.04) than those in the NS group.

Conclusions

Low-dose Dex in the perioperative period did not reduce the incidence of early POCD in thoracic surgery. However, it relieved postoperative pain, decreased the hospitalization expenses, and shortened the length of stay.

Effect of Different Modes of Administration of Dexmedetomidine Combined with Nerve Block on Postoperative Analgesia in Total Knee Arthroplasty

INTRODUCTION

Dexmedetomidine (DEX) as a nerve block adjuvant can significantly prolong analgesia. However, whether perineural or systemic administration of DEX is more beneficial in patients undergoing total knee arthroplasty (TKA) has not been thoroughly investigated. To this end, we evaluated the effects of perineural and systemic DEX administration on postoperative analgesia in patients undergoing TKA surgery.

METHODS

We randomly assigned patients undergoing TKA under general anesthesia combined with femoral nerve block and sciatic nerve block to one of three groups: (1) ropivacaine plus perineural dexmedetomidine (DP): 0.25% ropivacaine 40 mL plus 0.5 μg/kg dexmedetomidine; (2) ropivacaine plus systemic dexmedetomidine (DS): 0.25% ropivacaine 40 mL plus systemic 0.5 μg/kg dexmedetomidine; (3) control group (C): 0.25% ropivacaine 40 mL.

RESULTS

The average length of time until patients first experienced postoperative pain was significantly longer in the DP group (26.0 h [22.0-30.0 h]) than in the DS group (22.4 h [18-26.8 h]) and the control group (22.9 h [19.5-26.3 h], P = 0.001). For this result there was no significant difference between the DS and the control group. Compared with the DS and control groups, patients in the DP group had lower resting visual analogue scale (VAS) scores at 24, 48, and 72 h after surgery (P < 0.05). VAS activity scores at 12, 24, and 48 h after surgery in the DP group were lower than those in the DS and control groups, with a statistically significant difference (P < 0.05). Compared with the DS and control groups, the amount of postoperative opioids in the DP group was also significantly reduced, and the number of people needing postoperative rescue analgesia was significantly lower, with a statistical difference (P < 0.05). Meanwhile, the sleep satisfaction of patients in the DP group on the first night after surgery and the satisfaction with pain control at 72 h after surgery were both higher than those in the DS group and control group (P < 0.05).

CONCLUSIONS

Perineural administration of DEX can significantly prolong the interval until patients report pain for the first time after TKA, relieve postoperative pain, reduce postoperative opioid dosage, and improve postoperative sleep quality and satisfaction with pain control.

TRIAL REGISTRATION

The trial was registered at the Chinese Clinical Trial Registry, identifier ChiCTR1900025808.

Is Perioperative Dexmedetomidine Associated With a Reduced Risk of Perioperative Neurocognitive Disorders Following Cardiac Surgery? A Systematic Review and Meta-Analysis With Trial Sequential Analysis of Randomized Controlled Trials

Background: To assess the effect of dexmedetomidine on the reducing risk of perioperative neurocognitive disorders (PNDs) following cardiac surgery.

Methods: A systematic review and meta-analysis with trial sequential analysis (TSA) of randomized controlled trials were performed. PubMed, Embase, Cochrane Library, and CNKI databases (to August 16, 2020) were searched for relevant articles to analyze the incidence of PND for intraoperative or postoperative dexmedetomidine administration after cardiac surgery. PND included postoperative cognitive dysfunction (POCD) and postoperative delirium (POD).

Results: A total of 24 studies with 3,610 patients were included. Compared with the control group, the incidence of POD in the dexmedetomidine group was significantly lower (odds ratio [OR]: 0.59, 95% CI: 0.43–0.82, P = 0.001), with firm evidence from TSA. Subgroup analyses confirmed that dexmedetomidine reduced the incidence of POD with firm evidence following coronary artery bypass grafting surgery (OR: 0.45, 95% CI: 0.26–0.79, P = 0.005), and intervention during the postoperative period (OR: 0.48, 95% CI: 0.34–0.67, P < 0.001). Furthermore, the incidence of POD in the dexmedetomidine group was also decreased in mixed cardiac surgery (OR: 0.68, 95% CI: 0.47–0.98, P = 0.039). Irrespective of whether “Confusion Assessment Method/Confusion Assessment Method for intensive care unit” or “other tools” were used as diagnostic tools, the results showed a decreased risk of POD in the dexmedetomidine group. There was no significant difference in the incidence of POCD (OR: 0.47, 95% CI: 0.22–1.03, P = 0.060) between the two groups, but this result lacked firm evidence from TSA.

Conclusion: The administration of dexmedetomidine during the perioperative period reduced the incidence of POD in patients after cardiac surgery, but there was no significant benefit in the incidence of POCD. The effect of dexmedetomidine on the incidence of POD or POCD following different types of surgery and the optimal dose and timing of dexmedetomidine warrant further investigation.

Trial registration: PROSPERO registration number: CRD42020203980. Registered on September 13, 2020.

The Influence of Different Dexmedetomidine Doses on Cognitive Function at Early Period of Patients Undergoing Laparoscopic Extensive Total Hysterectomy

Background

This study aims to analyze the influence of different dexmedetomidine doses on cognitive function. It works on early periods of patients undergoing laparoscopic extensive total hysterectomy.

Method

119 patients with gynecological cancer underwent a laparoscopic extensive total hysterectomy. The operation was performed at the Affiliated Women's and Children's Hospital of Xiamen University from January 2019 to June 2020. The score of MoCA and the level of TNF-α, IL-6, S-100β protein, NSE, and GFAP of each group were compared 1 day before and after operation and 3 and 7 days after operation.

Result

In four groups, remifentanil, sufentanil, and propofol were given in the following order: group A > group D > group C > group B. Group A > group D > group C in terms of time spent in the recovery room, extubation, and recovery from anesthesia. The difference between groups B and C was not significant (P > 0.05). Compared with group A, group B scored higher in MoCA at 1 day (T1), 3 days (T2), and 7 days (T3) after operation (P < 0.05). At the same scoring point, the score was group B > group C > group D > group A. The POCD of four groups all occurred at 3 days after surgery. Compared with the T0 point, the level of TNF-α and IL-6 of the four groups at T1 and T2 was significantly increased (P < 0.05). At T3, the level of TNF-α and IL-6 gradually decreased. At various periods, the levels of S-100 protein, NSE, and GFAP in groups B, C, and D were lower than those in group A (P0.05). Group B had a substantially higher rate of bradycardia than the other three groups (P0.05). The incidence of chills, respiratory depression, and restlessness in group A differed significantly from the other three groups (P < 0.05).

Conclusion

Using 0.5 μg/kg dexmedetomidine during the perianaesthesia can effectively reduce anesthetic drugs in patients. They had a laparoscopic extensive complete hysterectomy, which helps to reduce the adverse responses and the occurrence of POCD while also protecting brain function.

Protective role of dexmedetomidine against sevoflurane-induced postoperative cognitive dysfunction via the microRNA-129/TLR4 axis

The involvement of Dexmedetomidine (Dex) has been indicated in postoperative cognitive dysfunction (POCD), while the mechanism is not well characterized. This study estimated the mechanism of Dex in POCD. Rats were anesthetized with sevoflurane (SEV) to evoke POCD and then subjected to Morris water maze test to detect the cognitive and behavioral function. Then, the damage of hippocampus and cortex, and apoptosis and activity of neurons were examined. Microarray analysis was performed to screen out the differentially expressed microRNAs (miRs) in rats after Dex treatment. The cognitive and behavioral functions and neuronal activity of rats were detected after miR-129 antagomir injection. The target of miR-129 was predicted. The levels of TLR4 and NF-κB p65 in hippocampus and cortex were measured. Dex treatment alleviated SEV-induced behavior and cognitive impairments in rats, promoted neuronal activity and hindered neuronal apoptosis. After treatment with Dex, miR-129 expression was elevated in brain tissues, and the neuroprotection of Dex on POCD rats was partially annulled after injection of miR-129 antagomir. Furthermore, miR-129 targeted TLR4 and prevented the phosphorylation of NF-κB p65. In summary, Dex ameliorated SEV-induced POCD by elevating miR-129 and inhibiting TLR4 and NF-κB p65 phosphorylation. This study may shed new lights on POCD treatment.

Update on the Mechanism and Treatment of Sevoflurane-Induced Postoperative Cognitive Dysfunction

Sevoflurane is one of the most widely used anesthetics for the induction and maintenance of general anesthesia in surgical patients. Sevoflurane treatment may increase the incidence of postoperative cognitive dysfunction (POCD), and patients with POCD exhibit lower cognitive abilities than before the operation. POCD affects the lives of patients and places an additional burden on patients and their families. Understanding the mechanism of sevoflurane-induced POCD may improve prevention and treatment of POCD. In this paper, we review the diagnosis of POCD, introduce animal models of POCD in clinical research, analyze the possible mechanisms of sevoflurane-induced POCD, and summarize advances in treatment for this condition.

Effect of Dexmedetomidine on Postoperative Sleep Quality: A Systematic Review

In this article, we conduct a systematic review of the literature to explore the specific role of dexmedetomidine (DEX) on postoperative sleep and its associated mechanisms at present. The electronic database Embase, MEDLINE/PubMed, the Cochrane Library, Web of Science, and Google Scholar were searched. The restriction terms included “dexmedetomidine”, “sleep” and “surgery”. The inclusion criteria were as following: 1) patients 18 years old or older; 2) DEX used in the perioperative period not just for critically ill patients in the intensive care unit (ICU); 3) prospective or retrospective studies. The review articles, conference abstracts, and animal studies were excluded. Out of the 22 articles which met the above criteria, 20 of them were randomized controlled studies and 2 of them were retrospective cohort studies. Infusion of DEX including during the surgery and after surgery at a low or high dose was shown to improve subjective and objective sleep quality, although 2 studies showed there is no evidence that the use of DEX improves sleep quality and 1 showed less sleep efficiency and shorter total sleep time in the DEX group. Other postoperative outcomes evaluated postoperative nausea and vomiting, pain, postoperative delirium bradycardia and hypotension. Outcomes of our systematic review showed that DEX has advantages in improving patients’ postoperative sleep quality. Combined with the use of general anesthetic, DEX provides a reliable choice for procedural sedation.

Dexmedetomidine Reverses Postoperative Spatial Memory Deficit by Targeting Surf1 and Cytochrome c

Anesthesia and surgery are associated with perioperative neurocognitive disorders (PND). Dexmedetomidine is known to improve PND in rats; however, little is known about the mechanisms. Male Sprague-Dawley rats were subjected to resection of the hepatic apex under propofol anesthesia to clinically mimic human abdominal surgery. The rats were divided into four groups: control group (C), anesthesia group (A), model group (M), and model + dex group (D). Cognitive function was evaluated with the Morris water maze (MWM). Neuronal morphology was observed with H&E staining, Nissl's staining and immunohistochemistry. Transcriptome analysis and quantitative real-time PCR were performed to investigate functional mitochondrial mRNA changes in the hippocampus. Protein levels were measured by Western blotting at 1, 3, and 7 days after surgery. Surgery-induced cognitive decline lasted for three days, but not seven days after surgery in the M group; however, rats in the D group were significantly improved by dexmedetomidine. No significant differences in the number of neurons were observed between the groups after surgery. Rats from the M group showed significantly greater expression levels of Iba-1 and GFAP compared with the C group and the D group. Rats in the M group demonstrated increased Surf1 and Cytochrome c expression on days 1 and 3, but not day 7; similar changes were not induced in rats in the D group. Dexmedetomidine appears to reverse surgery-induced behavior, mitigate the higher density of Iba-1 and GFAP, and downregulate the expression of Surf1 and Cytochrome c protein in the hippocampus of rats in a PND model.

Dexmedetomidine reverses MTX-induced neurotoxicity and inflammation in hippocampal HT22 cell lines via NCOA4-mediated ferritinophagy

The incidence of chemotherapy-induced cognitive impairment (CICI) has attracted massive attention. Some studies have demonstrated the neuroprotective effects of dexmedetomidine (DEX). Here, alterations in nuclear receptor coactivator 4 (NCOA4)-mediated ferritinophagy were investigated as the possible causes of DEX’s neuroprotection of HT22 cells against methotrexate (MTX)-induced neurotoxicity. We used various concentrations of DEX and NCOA4-siRNA to treat MTX-induced neurotoxicity and inflammation in HT22 cells. The biomarkers of HT22 cells viability, apoptosis and inflammatory were tested. The expression of ferritinophagy markers were detected in the HT22 cells by using western blot and Immunofluorescence. We found that 10 and 50 ng/mL of DEX alleviated MTX-induced hippocampal neuronal inflammatory injuries. Meanwhile, DEX also reversed MTX-induced iron and ROS overproduction. Increasing DEX concentrations caused significant falls in the expression of ferritin heavy chain 1 (FTH1). DEX also increased vital ferritinophagy markers, NCOA4 and LC3II. NCOA4-siRNA transfection annulled the neuroprotective effects of DEX on MTX-induced inflammation in HT22 cells. Additionally, because NCOA4-siRNA disrupted ferritinophagy, DEX’s inhibitory impact on MTX-induced iron and ROS overproduction in HT22 cells was also annihilated. DEX weakened MTX-provoked neurontoxicity in HT22 cells, possibly by improving NCOA4-mediated ferritinophagy. Our discoveries present further mechanisms for understanding the protective effects of DEX against MTX-induced cognitive impairment.

Effect of perioperative intravenous lidocaine on the incidence of short-term cognitive function after noncardiac surgery: A meta-analysis based on randomized controlled trials

OBJECTIVES

Postoperative cognitive dysfunction is a debilitating postoperative complication. The perioperative neuroprotective effect of lidocaine has conflicting results.

METHODS

In this qualitative review of randomized controlled clinical trials on the perioperative use of lidocaine, we report the effects of intravenous lidocaine on brain function after noncardiac surgery. Studies were identified from PubMed, MEDLINE, and Cochrane Central Register.

RESULTS

Of the 453 retrieved studies, 4 randomized trials were included. No significant association between the use of lidocaine postoperative cognitive states was found (risk ratio 0.67; 95% CI -0.02 to 1.36; I² 89%; p = .06).

CONCLUSIONS

Current evidence cannot suggest that perioperative intravenous use of lidocaine has pharmacological brain neuroprotection after noncardiac surgery. All the included studies were small-scale research, and the total number of participants was small; the results should be interpreted with caution.

The Effect and Optimal Dosage of Dexmedetomidine Plus Sufentanil for Postoperative Analgesia in Elderly Patients With Postoperative Delirium and Early Postoperative Cognitive Dysfunction: A Single-Center, Prospective, Randomized, Double-Blind, Controlled Trial

Background

Postoperative delirium (POD) and postoperative cognitive dysfunction (POCD) are common complications after major surgery among elderly patients. Dexmedetomidine (DEX) is less frequently explored for its effects in patients with postoperative neurocognitive disorders. This study investigated the effect and optimal dosage of DEX for patient-controlled analgesia (PCA) on POD and early POCD after major surgery among elderly patients.

Methods

Patients in four groups received continuous infusion of DEX 0, 100, 200, and 400 μg with sufentanil 150 μg for PCA immediately after surgery. POD and POCD were assessed on postoperative days 1, 2, 3, and 7 by using the Confusion Assessment Method (CAM) and Mini-Mental State Examination (MMSE) scales. Furthermore, the incidence of POD and POCD of all the four groups in postoperative 7 days classified by high risk factors (age, education, surgical site, and surgical category), sedation level, postoperative pain intensity, and side effects were assessed.

Results

The overall incidence rates of POD and early POCD 7 days after surgery were lower in the DEX 200 μg 400 μg groups than in the DEX 0 μg and 100 μg groups (P < 0.05). Compared with DEX 200 μg, DEX 400 μg reduced early POCD in patients who underwent open surgery (P < 0.05). There were no intergroup differences in the postoperative sedation level, pain intensity, and side effects.

Conclusion

The continuous infusion of DEX 200 μg or DEX 400 μg in PCA significantly decreased the incidence of POD and early POCD after major surgery without increasing any side effects. Compared with DEX 200 μg, DEX 400 μg was preferred for reducing early POCD in patients who underwent open surgery.

Dexmedetomidine alleviates neurobehavioral impairments and myelination deficits following lipopolysaccharide exposure in early postnatal rats

AIMS

White matter injury (WMI) is the main form of brain injury in preterm neonate survivors, and perinatal inflammation is implicated in the pathogenesis of WMI. It has been demonstrated that dexmedetomidine, an anesthetic adjuvant, possesses neuroprotective effects in both preclinical and clinical trials. The present study was conducted to explore whether dexmedetomidine could protect against neurobehavioral impairments and myelination deficits caused by lipopolysaccharide (LPS) exposure in the early postnatal rat brain.

MAIN METHODS

LPS (2 mg/kg) was intraperitoneally (i.p.) injected in Sprague-Dawley rat pups on postnatal day 2 (P2). Dexmedetomidine (25 μg/kg) or vehicle was given i.p. immediately after LPS injection. STAT3 and p-STAT3 expression were detected by western blot in rat brain 24 h after drug administration. Immunostaining for GFAP to was performed to evaluate astrocytic response at 24 h post-LPS and P14. Neurobehavioral tests (the righting reflex, negative geotaxis, and wire hanging maneuver tests) were performed from P5 to P10. Histological analysis of myelin content was accessed by immunohistochemistry for CNPase and MBP at P14.

KEY FINDINGS

Our results showed that treatment with dexmedetomidine significantly ameliorated LPS-induced neurobehavioral abnormalities and myelin damage, which is accompanied by suppression of STAT3 activation and reactive astrogliosis.

SIGNIFICANCE

Dexmedetomidine can alleviate neurobehavioral impairments and myelination deficits after LPS exposure in early postnatal rats, probably by mitigating STAT3-mediated reactive astrogliosis. Our results suggest that dexmedetomidine might be a promising agent to treat brain injury in neonates.

Dexmedetomidine for early postoperative cognitive dysfunction after video-assisted thoracoscopic lobectomy in elderly male patients with lung cancer

This retrospective study explored the efficacy and safety of dexmedetomidine in treating early postoperative cognitive dysfunction (EPPNCD) after video-assisted thoracoscopic lobectomy (VATL) in elderly male patients with lung cancer (LC).This study included a total of 80 elderly male patients with LC who received VATL. All of them were equally assigned to a treatment group and a control group, with 40 patients each group. The primary outcome included cognitive dysfunction, as evaluated by mini-mental state examination scale. The secondary outcomes consisted of incidence of EPPNCD, lung function (as measured by forced vital capacity, forced expiratory volume in 1 second, peak expiratory flow, and maximal voluntary ventilation), and adverse events. All outcome data were analyzed before and 3 days after surgery.After surgery, all patients in the treatment group exerted better efficacy in mini-mental state examination scale (P < .01) and incidence of EPPNCD (P = .03), than patients in the control group. However, no significant differences were detected in forced vital capacity (P = .65), forced expiratory volume in 1 second (P = .50), peak expiratory flow (P = .73), and maximal voluntary ventilation (P = .27) between 2 groups. In addition, there is similar safety profile between 2 groups.The findings of this study showed that dexmedetomidine may benefit EPPNCD after VATL in elderly male patients with LC. Future studies are needed to warrant the present conclusions.

Postoperative neurocognitive disorders

A decline in cognitive function is a frequent complication of major surgery. Postoperative cognitive impairments have generally been divided into short- (postoperative delirium) and long-term disturbances (postoperative cognitive dysfunction [POCD]). Long-term impairments are often subtle and overlooked. They need to be objectively assessed using neuropsychological tests to be diagnosed. Although POCD has been the subject of considerable research over the past decades, it remains uncertain why some patients do not return to preoperative levels of cognitive function. Surgery and anesthesia have both been implicated to play a role in POCD development, and certain patient-related factors, such as advanced age and low preoperative baseline cognitive function, have consistently been found to predict postoperative cognitive decline. This article will present an overview of POCD and its etiology and provide advice on possible strategies on its prevention.

Protective effects of dexmedetomidine on the survival of random flaps

BACKGROUND

Random flaps can be used to repair wounds and improve shape and functional reconstruction, but inflammation and necrosis limit their application. Modified McFarlane flap models were constructed on the backs of rats. We hypothesized that dexmedetomidine (DEX) could improve the survival rate of ischemic random flaps.

METHODS

Sixty rats were randomly divided into three groups: a low-dose DEX group (DEX-L group, 10 μg/kg/D), a high-dose DEX group (DEX-H group, 20 μg/kg/D) and a control group (0.9 % saline equivalent). On day 7 after flap construction, the survival percentage of the flap model was calculated. Hematoxylin and eosin staining (H&E) was used to evaluate the histopathological status of the flaps and microvessel density (MVD). Lead oxide/gelatin angiography was used to detect angiogenesis, and laser Doppler flow imaging (LDF) was used to detect blood perfusion. The levels of superoxide dismutase (SOD) and malondialdehyde (MDA) in the middle areas of the flaps were measured to show the level of oxidative stress. The expressions of Toll-like receptor (TLR4), nuclear factor-kappa B (NF-κB), interleukin (IL)-1β, IL-6, tumor necrosis factor-α (TNF-α) and vascular endothelial growth factor (VEGF) were detected by immunohistochemistry.

RESULTS

DEX significantly increased the average survival percentage of the flaps and reduced ischemia and necrosis of the distal end of the flaps. SOD activity significantly increased, while MDA significantly decreased, indicating that DEX reduces oxidative damage. The expression of inflammatory immunoregulatory proteins (TLR4, NF-κB) was downregulated, and the levels of inflammatory factors (IL-1β, IL-6 and TNF-α) were lower. In addition, DEX upregulated VEGF expression, promoted angiogenesis, and increased blood perfusion.

CONCLUSION

In random flap transplantation, a high dose of DEX is beneficial to flap survival.

CD200R Is Involved in the Anti-inflammatory Effect of Dexmedetomidine in Lipopolysaccharide-Stimulated Microglia

Dexmedetomidine has been confirmed to have anti-inflammatory effect in numerous diseases. However, the detailed mechanism is still unknown. We explore the hypothesis that CD200R is related to the anti-inflammatory effect of dexmedetomidine. Primary microglia were treated with different concentrations of dexmedetomidine followed with lipopolysaccharide (LPS) for 24 h. Interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and interleukin-10 (IL-10) were measured by enzyme-linked immunosorbent assay. Arginase 1 (Arg1), IL-6, and TNF-α were measured by TR-PCR. CD200R was observed by Western blot analysis. We found dexmedetomidine reduced LPS-induced IL-6 and TNF-α production and increase Arg1 in primary microglia. CD200R expression was downregulated by LPS and dexmedetomidine can attenuate the effect of LPS. Our results showed that CD200R may be related to the anti-inflammatory effect of dexmedetomidine.

Whole transcriptome sequencing reveals dexmedetomidine-improves postoperative cognitive dysfunction in rats via modulating lncRNA

The aim of this study was to explore the underlying mechanism and function of dexmedetomidine (Dex)-regulated long non-coding RNAs (lncRNAs) in improving postoperative cognitive dysfunction (POCD) in rats. The established POCD model, Dex treatment model in rats, Morris water maze testing, and HE staining assays were used to evaluate the efficacy of Dex in POCD treatment in rats. Hippocampus samples of rats from the POCD group and the Dex group were used for lncRNA sequencing. The expression of five differentially expressed lncRNAs (DElncRNAs) was verified by quantitative reverse transcription PCR (qRT-PCR). Competing endogenous RNAs (ceRNA) network was constructed using Cytoscape. The concentration of inflammatory cytokines were measured by ELISA. Microglia proliferation and apoptosis were assessed using CCK-8 assay and flow cytometry, respectively. In the Dex group, the escape latency was shorter, neuron cell injury levels were alleviated, and the expression levels of TNF-α and IL-1β were significantly down-regulated compared with the POCD group. A total of 60 DE lncRNAs were identified, including 16 up- and 44 down-regulated lncRNAs in the Dex group. KEGG pathway analysis revealed that DElncRNAs were significantly enriched in cytokine-cytokine receptor interactions, the p53 signaling pathway, and the NF-kappa B signaling pathway. The qRT-PCR results and ceRNA network suggested that the lncRNA LOC102546895 may play a key role in POCD. LOC102546895 inhibited proliferation while promoting apoptosis in microglial cells and promoted the mRNA and protein expression of the target gene Npas4. Our findings showed that Dex alleviated POCD in rats and regulated lncRNAs expression profile in the hippocampus tissues of rats with POCD. In conclusion, our study outcome proposes that Dex-regulated lncRNA LOC102546895 may play a role in rats with POCD through targeting Npas4.

Dexmedetomidine Improves Cardiovascular and Ventilatory Outcomes in Critically Ill Patients: Basic and Clinical Approaches

Dexmedetomidine (DEX) is a highly selective α2-adrenergic agonist with sedative and analgesic properties, with minimal respiratory effects. It is used as a sedative in the intensive care unit and the operating room. The opioid-sparing effect and the absence of respiratory effects make dexmedetomidine an attractive adjuvant drug for anesthesia in obese patients who are at an increased risk for postoperative respiratory complications. The pharmacodynamic effects on the cardiovascular system are known; however the mechanisms that induce cardioprotection are still under study. Regarding the pharmacokinetics properties, this drug is extensively metabolized in the liver by the uridine diphosphate glucuronosyltransferases. It has a relatively high hepatic extraction ratio, and therefore, its metabolism is dependent on liver blood flow. This review shows, from a basic clinical approach, the evidence supporting the use of dexmedetomidine in different settings, from its use in animal models of ischemia-reperfusion, and cardioprotective signaling pathways. In addition, pharmacokinetics and pharmacodynamics studies in obese subjects and the management of patients subjected to mechanical ventilation are described. Moreover, the clinical efficacy of delirium incidence in patients with indication of non-invasive ventilation is shown. Finally, the available evidence from DEX is described by a group of Chilean pharmacologists and clinicians who have worked for more than 10 years on DEX.

The mechanism of lipopolysaccharide administration-induced cognitive function impairment caused by glucose metabolism disorder in adult rats

This essay aims to make investigation on the mechanism of glucose metabolism disorder and Lipopolysaccharide administration-induced cognitive function impairment in adult rats with surgery. Methods: Divide the objects, 40 male Sprague-Dawley rats at the age of 9 months, into 4 groups. Provide unilateral nephrectomy surgery and/or lipopolysaccharide intraperitoneal injection. Postoperative cognitive function evaluation would be tested by the Morris water maze. Rats with Postoperative Cognitive Dysfunction (POCD) were scanned to analyze the brain glucose metabolism by means of 18F-FDG PET/CT. Phosphatidylinositol 3-Kinase (PI3K), Protein Kinase β (AKT), Insulin Substrates Receptor-2 (IRS-2) and Glucose Transporter 4 (GLUT4) were detected as well. Data will be captured through gene expression in POCD rats via Quantitative Real-Time PCR (QRT-PCR). On the other side, Western Blot was used to measure the expression levels of IRS-2, p-IRS-2, p-PI3K, PI3K, p-AKT, AKT, GLUT4, and p-GLUT4. Results: During the Morris water maze test, the staging time (latency) of rats in each group was becoming short gradually as the training progressed. The incubation time of Day 5 of each group was shorter than that of Day 1 (P < 0.05). On the Day 3 after the surgery, the average target quadrant residence time of Group S+L (100 μg/Kg) was shorter, compared with Group C, L and S. Of which, the average number of perforation was reduced greater than that of Group C (P < 0.05). The average swimming speed of the groups is of no distinct difference (P > 0.05). After the operation, there was no great difference shown among the subjects (P > 0.05) in the average residence time of the target quadrant, the mean number of passages, and the mean swimming speed. On Day 3, the average latency of Group S+L (100 μg/Kg) was longer than Group C (P < 0.05) in the working memory test after the operation. The average latency of rats in Group L and S was showed longer than that in Group C, with tiny difference (P > 0.05). In the 7-Day working memory test, the average latency of the rats in Group L, S and S+L (100 μg/Kg) was obviously longer than that in Group C. Comparing to preoperative rats, POCD rats of Group S+L (100 μg/Kg) were scanned by 18F-FDG PET/CT three days later after the operation. Its SUVmax of the frontal and temporal lobe areas were decreased significantly (P < 0.05). However, difference degree was not significantly shown in the SUVmax between Group C and the preoperative rats (P > 0.05). In comparison with the gene expression of of Group C, the PI3K, IRS-2, AKT and GLUT4 mRNA genes are the key genes in the insulin signaling pathways of the hippocampus of the POCD rats. The expression level was reduced. The expression level of all protein of PI3K, IRS-2, GLUT4 and AKT in the POCD rats was of no great contrast with that in Group C. But for IRS-2 protein, the phosphorylation level has increased, and meanwhile decreased for AKT, PI3K and GLUT4 proteins (P < 0.05). Conclusions: Adult SD rats cognitive dysfunction model treated with unilateral nephrectomy combined and 100 μg/kg LPS intraperitoneal injection were led to abnormal both brain glucose metabolism and insulin expression. The proved phenomenal results signal pathway-related proteins PI3K, IRS-2, AKT and GLUT4. It reached the conclusion that surgical trauma, rather than anesthesia, leads to impaired cognitive function. PI3K, IRS-2, AKT, and GLUT4pathway of brain can be partial explanations of the pathogenesis of POCD.

State of the clinical science of perioperative brain health: report from the American Society of Anesthesiologists Brain Health Initiative Summit 2018

Cognitive recovery after anaesthesia and surgery is a concern for older adults, their families, and caregivers. Reports of patients who were 'never the same' prompted a scientific inquiry into the nature of what patients have experienced. In June 2018, the ASA Brain Health Initiative held a summit to discuss the state of the science on perioperative cognition, and to create an implementation plan for patients and providers leveraging the current evidence. This group included representatives from the AARP (formerly the American Association of Retired Persons), American College of Surgeons, American Heart Association, and Alzheimer's Association Perioperative Cognition and Delirium Professional Interest Area. This paper summarises the state of the relevant clinical science, including risk factors, identification and diagnosis, prognosis, disparities, outcomes, and treatment of perioperative neurocognitive disorders. Finally, we discuss gaps in current knowledge with suggestions for future directions and opportunities for clinical and translational projects.

Special Considerations for the Aging Brain and Perioperative Neurocognitive Dysfunction

Postoperative delirium and postoperative cognitive dysfunction (POCD) occur commonly in older adults after surgery and are frequently underrecognized. Delirium has been associated with worse outcomes, and both delirium and cognitive dysfunction increase the risk of long-term cognitive decline. Although the pathophysiology of delirium and POCD have not been clearly defined, risk factors for both include increasing age, lower levels of education, and baseline cognitive impairment. In addition, developing delirium increases the risk of POCD. This article examines interventions that may reduce the risk of developing delirium and POCD and improve long-term recovery and outcomes in the vulnerable older population.