Role of adenosine A2A receptors in the loss of consciousness induced by propofol anesthesia.

The mechanism of propofol-anesthesia-induced loss of consciousness (LOC) remains largely unknown. We speculated that the adenosine A2A receptor serves as a vital molecular target in regulating LOC states under propofol anesthesia. c-Fos staining helped observe the changes in the neuronal activity in the nucleus accumbens (NAc). Initially, the adenosine signals in the NAc were measured under propofol anesthesia using fiber photometry recordings. Then, behavior tests and electrophysiological recordings were used to verify the effect of systemic A2A R agonist or antagonist treatment on propofol anesthesia. Next, the microinjection technique was used to clarify the role of the NAc A2A R under propofol anesthesia. Fiber photometry recordings were applied to assess the effect of A2A R agonist or antagonist systemic treatment on adenosine signal alterations in the NAc during propofol anesthesia. Then, as the GABAergic neurons are the main neurons in the NAc, we further measured the neuronal activity of GABAergic neurons. In our study, propofol anesthesia enhanced the neuronal activity in the NAc, and the adenosine signals were increased in the NAc. SCH58261 reduced the LOC time and sedative depth, while CGS21680 increased those via intraperitoneal injection. Additionally, CGS21680 increased the changes in delta, theta, alpha, beta, and low-gamma oscillations in the NAc. Moreover, microinjection of SCH58261 significantly shortened the LOC time, whereas microinjection of CGS21680 into the NAc significantly prolonged the LOC duration. The results illustrated that after A2A R agonist administration, the level of extracellular adenosine signals in the NAc was decreased and the neuronal activity of GABAergic neurons was enhanced, whereas after A2A R antagonist administration via intraperitoneal injection, the opposite occurred. This study reveals the vital role of the A2A R in propofol-induced LOC and that the A2A R could affect the maintenance of propofol anesthesia.

Preoperative Acute Sleep Deprivation Causes Postoperative Pain Hypersensitivity and Abnormal Cerebral Function.

Preoperative sleep loss can amplify post-operative mechanical hyperalgesia. However, the underlying mechanisms are still largely unknown. In the current study, rats were randomly allocated to a control group and an acute sleep deprivation (ASD) group which experienced 6 h ASD before surgery. Then the variations in cerebral function and activity were investigated with multi-modal techniques, such as nuclear magnetic resonance, functional magnetic resonance imaging, c-Fos immunofluorescence, and electrophysiology. The results indicated that ASD induced hyperalgesia, and the metabolic kinetics were remarkably decreased in the striatum and midbrain. The functional connectivity (FC) between the nucleus accumbens (NAc, a subregion of the ventral striatum) and the ventrolateral periaqueductal gray (vLPAG) was significantly reduced, and the c-Fos expression in the NAc and the vLPAG was suppressed. Furthermore, the electrophysiological recordings demonstrated that both the neuronal activity in the NAc and the vLPAG, and the coherence of the NAc-vLPAG were suppressed in both resting and task states. This study showed that neuronal activity in the NAc and the vLPAG were weakened and the FC between the NAc and the vLPAG was also suppressed in rats with ASD-induced hyperalgesia. This study highlights the importance of preoperative sleep management for surgical patients.

A Noradrenergic Lesion Attenuates Surgery-Induced Cognitive Impairment in Rats by Suppressing Neuroinflammation.

Postoperative cognitive dysfunction (POCD) is a common postoperative neurocognitive complication in elderly patients. However, the specific pathogenesis is unknown, and it has been demonstrated that neuroinflammation plays a key role in POCD. Recently, increasing evidence has proven that the locus coeruleus noradrenergic (LCNE) system participates in regulating neuroinflammation in some neurodegenerative disorders. We hypothesize that LCNE plays an important role in the neuroinflammation of POCD. In this study, 400 µg of N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine (DSP-4) was injected intracerebroventricularly into each rat 7 days before anesthesia/surgery to deplete the locus coeruleus (LC) noradrenaline (NE). We applied a simple laparotomy and brief upper mesenteric artery clamping surgery as the rat POCD model. The open field test, novel objection and novel location (NL) recognition, and Morris water maze (MWM) were performed to assess postoperative cognition. High-performance liquid chromatography (HPLC) was used to measure the level of NE in plasma and brain tissues, and immunofluorescence staining was applied to evaluate the activation of microglia and astrocytes. We also used enzyme-linked immune-sorbent assay (ELISA) to assess the levels of inflammatory cytokines and brain-derived neurotrophic factor (BDNF). Pretreatment with DSP-4 decreased the levels of systemic and central NE, increased the level of interleukin-6 (IL-6) in the plasma at 6 h after the surgery, decreased the concentration of IL-6 in the prefrontal cortex and hippocampus, and decreased the level of interleukin-1ß (IL-1ß) in the plasma, prefrontal cortex, and hippocampus at 1 week postoperatively. In addition, DSP-4 treatment attenuated hippocampal-dependent learning and memory impairment in rats with POCD, with a downregulation of the activation of microglia and astrocytes in the prefrontal cortex and hippocampus. In conclusion, these findings provide evidence of the effects of LCNE in modulating neuroinflammation in rats with POCD and provide a new perspective in the prevention and treatment of POCD.

The adenosine A2A receptor alleviates postoperative delirium-like behaviors by restoring blood cerebrospinal barrier permeability in rats.

Postoperative delirium (POD) is a common post-operative complication in elderly patients that is associated with increased morbidity and mortality. However, the neuropathogenesis of this complication remains unknown. The blood-cerebrospinal fluid barrier (BCB) and brain-blood barrier (BBB) are composed of tight junctions between cells that form physical barriers, and BBB damage plays an important role in the neuropathogenesis of POD. Nevertheless, the role of BCB in POD remains to be elucidated. Herein, we investigated the effect of adenosine A2A receptor (A2A R), a key regulator of the permeability of barriers, on surgery-induced increased permeability of BCB and POD-like behaviors. Open field, buried food, and Y maze tests were used to evaluate behavioral changes in rats after surgery. Levels of tight junction proteins, adherens junction proteins, A2A R, GTP-RhoA, and ROCK2 in the choroid plexus were assessed by western blotting. The concentrations of NaFI and FITC-dextran in the cerebrospinal fluid (CSF) were detected by fluorescence spectrophotometry. Transmission electron microscopy was applied to observe the ultrastructure of the choroid plexus. Surgery/anesthesia decreased the levels of tight junction (e.g., ZO-1, occludin, and claudin1) proteins, increased concentrations of NaFI and FITC-dextran in CSF, damaged the ultrastructure of choroid plexus, and induced POD-like behaviors in rats. An A2A R antagonist alleviated POD-like behaviors in rats. Furthermore, the A2A R antagonist increased the levels of tight junction proteins and restored the permeability of BCB in rats with POD. Fasudil, a selective Rho-associated protein kinase 2 (ROCK2) inhibitor, ameliorated POD-like behaviors induced by A2A R activation. Moreover, fasudil also abolished the increased levels of GTP-RhoA/ROCK2, decreased levels of tight junction proteins, and increased permeability of BCB caused by A2A R activation. Our findings demonstrate that A2A R might participate in regulating BCB permeability in rats with POD via the RhoA/ROCK2 signaling pathway, which suggests the potential of A2A R as a therapeutic target for POD.

Neuronal mechanisms of adenosine A2A receptors in the loss of consciousness induced by propofol general anesthesia with functional magnetic resonance imaging.

Propofol is the most common intravenous anesthetic agent for induction and maintenance of anesthesia, and has been used clinically for more than 30 years. However, the mechanism by which propofol induces loss of consciousness (LOC) remains largely unknown. The adenosine A2A receptor (A2A R) has been extensively proven to have an effect on physiological sleep. It is, therefore, important to investigate the role of A2A R in the induction of LOC using propofol. In the present study, the administration of the highly selective A2A R agonist (CGS21680) and antagonist (SCH58261) was utilized to investigate the function of A2A R under general anesthesia induced by propofol by means of animal behavior studies, resting-state magnetic resonance imaging and c-Fos immunofluorescence staining approaches. Our results show that CGS21680 significantly prolonged the duration of LOC induced by propofol, increased the c-Fos expression in nucleus accumbens (NAc) and suppressed the functional connectivity of NAc-dorsal raphe nucleus (DR) and NAc-cingulate cortex (CG). However, SCH58261 significantly shortened the duration of LOC induced by propofol, decreased the c-Fos expression in NAc, increased the c-Fos expression in DR, and elevated the functional connectivity of NAc-DR and NAc-CG. Collectively, our findings demonstrate the important roles played by A2A R in the LOC induced by propofol and suggest that the neural circuit between NAc-DR maybe controlled by A2A R in the mechanism of anesthesia induced by propofol.

Netrin-1 Ameliorates Postoperative Delirium-Like Behavior in Aged Mice by Suppressing Neuroinflammation and Restoring Impaired Blood-Brain Barrier Permeability.

Postoperative delirium (POD) is a common and serious postoperative complication in elderly patients, and its underlying mechanism is elusive and without effective therapy at present. In recent years, the neuroinflammatory hypothesis has been developed in the pathogenesis of POD, in which the damaged blood-brain barrier (BBB) plays an important role. Netrin-1 (NTN-1), an axonal guidance molecule, has been reported to have strong inflammatory regulatory and neuroprotective effects. We applied NTN-1 (45 µg/kg) to aged mice using a POD model with a simple laparotomy to assess their systemic inflammation and neuroinflammation by detecting interleukin-6 (IL-6), interleukin-10 (IL-10), and high mobility group box chromosomal protein-1 (HMGB-1) levels. We also assessed the reactive states of microglia and the permeability of the BBB by detecting cell junction proteins and the leakage of dextran. We found that a single dose of NTN-1 prophylaxis decreased the expression of IL-6 and HMGB-1 and upregulated the expression of IL-10 in the peripheral blood, hippocampus, and prefrontal cortex. Nerin-1 reduced the activation of microglial cells in the hippocampus and prefrontal cortex and improved POD-like behavior. NTN-1 also attenuated the anesthesia/surgery-induced increase in BBB permeability by upregulating the expression of tight junction-associated proteins such as ZO-1, claudin-5, and occludin. These findings confirm the anti-inflammatory and BBB protective effects of NTN-1 in an inflammatory environment in vivo and provide better insights into the pathophysiology and potential treatment of POD.

Effect of pre-administered flurbiprofen axetil on the EC50 of propofol during anesthesia in unstimulated patients: a randomized clinical trial / Efeito da pré‐ administração de flurbiprofeno axetil na CE50 do propofol durante anestesia em pacientes não estimulados: estudo clínico randomizado

Abstract Background and objectives Preoperative use of flurbiprofen axetil (FA) is extensively adopted to modulate the effects of analgesia. However, the relationship between FA and sedation agents remains unclear. In this study, we aimed to investigate the effects of different doses of FA on the median Effective Concentration (EC50) of propofol. Methods Ninety-six patients (ASA I or II, aged 18-65 years) were randomly assigned into one of four groups in a 1:1:1:1 ratio. Group A (control group) received 10 mL of Intralipid, and groups B, C and D received 0.5 mg.kg−1, 0.75 mg.kg−1 and 1 mg.kg−1 of FA, respectively, 10 minutes before induction. The depth of anesthesia was measured by the Bispectral Index (BIS). The "up-and-down" method was used to calculate the EC50 of propofol. During the equilibration period, if BIS ≤ 50 (or BIS > 50), the next patient would receive a 0.5 µg.mL−1-lower (or -higher) propofol Target-Controlled Infusion (TCI) concentration. The hemodynamic data were recorded at baseline, 10 minutes after FA administration, after induction, after intubation and 15 minutes after intubation. Results The EC50 of propofol was lower in Group C (2.32 µg.mL−1, 95% Confidence Interval [95% CI] 1.85-2.75) and D (2.39 µg.mL−1, 95% CI 1.91-2.67) than in Group A (2.96 µg.mL−1, 95% CI 2.55-3.33) (p = 0.023, p = 0.048, respectively). There were no significant differences in the EC50 between Group B (2.53 µg.mL−1, 95% CI 2.33-2.71) and Group A (p > 0.05). There were no significant differences in Heart Rate (HR) among groups A, B and C. The HR was significantly lower in Group D than in Group A after intubation (66 ± 6 vs. 80 ± 10 bpm, p < 0.01) and 15 minutes after intubation (61 ± 4 vs. 70 ± 8 bpm, p < 0.01). There were no significant differences among the four groups in Mean Arterial Pressure (MAP) at any time point. The MAP of the four groups was significantly lower after induction, after intubation, and 15 minutes after intubation than at baseline (p < 0.05). Conclusion High-dose FA (0.75 mg.kg−1 or 1 mg.kg−1) reduces the EC50 of propofol, and 1 mg.kg−1 FA reduces the HR for adequate anesthesia in unstimulated patients. Although this result should be investigated in cases of surgical stimulation, we suggest that FA pre-administration may reduce the propofol requirement when the depth of anesthesia is measured by BIS.

Resumo Justificativa e objetivos A administração pré‐operatória de Flurbiprofeno Axetil (FA) é amplamente usada para a modulação da analgesia. No entanto, a relação entre FA e fármacos sedativos permanece obscura. Neste estudo, nosso objetivo foi investigar os efeitos de diferentes doses de FA na Concentração Efetiva mediana (CE50) do propofol. Métodos Noventa e seis pacientes (ASA I ou II, com idades de 18-65 anos) foram alocados aleatoriamente em quatro grupos na proporção de 1:1:1:1. Dez minutos antes da indução, o Grupo A (grupo controle) recebeu 10 mL de Intralipid, enquanto os grupos B, C e D receberam FA na dose de 0,5 mg.kg‐1; 0,75 mg.kg‐1 e 1 mg.kg‐1, respectivamente. A profundidade da anestesia foi medida pelo Índice Bispectral (BIS). O método up‐and‐down foi usado para calcular a CE50 do propofol. Durante o período de equilíbrio, se o valor do BIS fosse ≤ 50 ou BIS > 50, o próximo paciente tinha a infusão de propofol ajustada para uma concentração alvo‐controlada 0,5 µg.mL‐1 inferior ou superior, respectivamente. Os dados hemodinâmicos foram registrados no início do estudo, 10 minutos após a administração de FA, após a indução, após a intubação e 15 minutos após a intubação. Resultados A CE50 do propofol foi menor no Grupo C (2,32 µg.mL‐1, Intervalo de Confiança de 95% [95% IC] 1,85-2,75) e D (2,39 µg.mL‐1, 95% IC 1,91-2,67) do que no Grupo A (2,96 µg.mL‐1; 95% IC 2,55-3,33) (p = 0,023, p = 0,048, respectivamente). Não houve diferenças significantes na CE50 entre o Grupo B (2,53 µg.mL‐1, 95% IC 2,33-2,71) e o Grupo A (p > 0,05). Não houve diferenças significantes na Frequência Cardíaca (FC) entre os grupos A, B e C. A FC foi significantemente menor no grupo D do que no grupo A após a intubação (66 ± 6 vs. 80 ± 10 bpm, p < 0,01) e 15 minutos após a intubação (61 ± 4 vs. 70 ± 8 bpm, p < 0,01). Não houve diferenças significantes entre os quatro grupos na Pressão Arterial Média (PAM) em qualquer momento. A PAM dos quatro grupos foi significantemente menor após a indução, após a intubação e 15 minutos após a intubação do que na linha de base (p < 0,05). Conclusão FA em altas doses (0,75 mg.kg‐1 ou 1 mg.kg‐1) reduz a CE50 do propofol, e 1 mg.kg‐1 de FA reduz a FC durante níveis adequados de anestesia em pacientes não estimulados. Embora esse resultado deva ser investigado na presença de estimulação cirúrgica, sugerimos que a pré‐administração de FA pode reduzir a necessidade de propofol durante anestesia cuja profundidade seja monitorada pelo BIS.

Neuroprotectin D1 Protects Against Postoperative Delirium-Like Behavior in Aged Mice.

Postoperative delirium (POD) is the most common postoperative complication affecting elderly patients, yet the underlying mechanism is elusive, and effective therapies are lacking. The neuroinflammation hypothesis for the pathogenesis of POD has recently emerged. Accumulating evidence is supporting the role of specialized proresolving lipid mediators (SPMs) in regulating inflammation. Neuroprotectin D1 (NPD1), a novel docosahexaenoic acid (DHA)-derived lipid mediator, has shown potent immunoresolvent and neuroprotective effects in several disease models associated with inflammation. Here, using a mouse model of POD, we investigated the role of NPD1 in postoperative cognitive impairment by assessing systemic inflammatory changes, the permeability of the blood-brain barrier (BBB), neuroinflammation, and behavior in aged mice at different time points. We report that a single dose of NPD1 prophylaxis decreased the expression of tumor necrosis factor alpha TNF-α and interleukin (IL)-6 and upregulated the expression of IL-10 in peripheral blood, the hippocampus, and the prefrontal cortex. Additionally, NPD1 limited the leakage of the BBB by increasing the expression of tight junction (TJ)-associated proteins such as ZO-1, claudin-5, and occludin. NPD1 also abolished the activation of microglia and astrocytes in the hippocampus and prefrontal cortex, which is associated with improved general and memory function after surgery. In addition, NPD1 treatment modulated the inflammatory cytokine expression profile and improved the expression of the M2 marker CD206 in lipopolysaccharide (LPS)-stimulated macrophages, which may partly explain the beneficial effects of NPD1 on inflammation. Collectively, these findings shed light on the proresolving activities of NPD1 in the pro-inflammatory milieu both in vivo and in vitro and may bring a novel therapeutic approach for POD.

Successful management of seven cases of critical COVID-19 with early noninvasive-invasive sequential ventilation algorithm and bundle pharmacotherapy.

We report the clinical and laboratory findings and successful management of seven patients with critical coronavirus disease 2019 (COVID-19) requiring mechanical ventilation (MV). The patients were diagnosed based on epidemiological history, clinical manifestations, and nucleic acid testing. Upon diagnosis with COVID-19 of critical severity, the patients were admitted to the intensive care unit, where they received early noninvasive-invasive sequential ventilation, early prone positioning, and bundle pharmacotherapy regimen, which consists of antiviral, anti-inflammation, immune-enhancing, and complication-prophylaxis medicines. The patients presented fever (n = 7, 100%), dry cough (n = 3, 42.9%), weakness (n = 2, 28.6%), chest tightness (n = 1, 14.3%), and/or muscle pain (n = 1, 14.3%). All patients had normal or lower than normal white blood cell count/lymphocyte count, and chest computed tomography scans showed bilateral patchy shadows or ground glass opacity in the lungs. Nucleic acid testing confirmed COVID-19 in all seven patients. The median MV duration and intensive care unit stay were 9.9 days (interquartile range, 6.5-14.6 days; range, 5-17 days) and 12.9 days (interquartile range, 9.7-17.6 days; range, 7-19 days), respectively. All seven patients were extubated, weaned off MV, transferred to the common ward, and discharged as of the writing of this report. Thus, we concluded that good outcomes for patients with critical COVID-19 can be achieved with early noninvasive-invasive sequential ventilation and bundle pharmacotherapy.

Cancer stem cell-specific expression profiles reveal emerging bladder cancer biomarkers and identify circRNA_103809 as an important regulator in bladder cancer.

Bladder cancer stem cells (BCSCs), exhibiting self-renewal and differentiation capacities, may contribute to the tumor initiation, metastasis, recurrence and drug resistance of bladder cancer. However, the underlying functional mechanisms of BCSCs remain to be clarified. In this study, we describe the differentially-expressed mRNAs, lncRNAs, and circRNAs in BCSCs compared with that in bladder cancer non-stem cells (BCNSCs) through the transcriptome microarray data analysis using bladder cancer patients' specimens. CircRNA_103809, the top one among the highly expressed circRNA identified in BCSCs, promotes the self-renewal, migration and invasion capabilities of bladder cancer by acting as a miR-511 sponge. Additionally, GO and KEGG pathway analysis suggest the differentially expressed genes identified may be involved in the cellular metabolism, differentiation and metastasis regulation of the cancer cells. Co-expression networks of lncRNAs/mRNAs and circRNAs/mRNAs constructed by WGCNA give a picture of the non-coding/coding RNAs regulating patterns in BCSCs. Notably, as core genes in the networks, AHCY, C6orf136 and LRIG1 show high potential to be prognosticators for bladder cancer. Therefore, further studies of non-coding RNA functional mechanisms in BCSCs is valuable for detecting the pathogenic mechanisms and discovering novel biomarkers in bladder cancer.

Surgery/Anesthesia disturbs mitochondrial fission/fusion dynamics in the brain of aged mice with postoperative delirium.

Postoperative delirium (POD) is a common complication following surgery and anesthesia (Surgery/Anesthesia). Mitochondrial dysfunction, which is demonstrated by energy deficits and excessively activated oxidative stress, has been reported to contribute to POD. The dynamic balance between mitochondrial fusion and fission processes is critical in regulating mitochondrial function. However, the impact of Surgery/Anesthesia on mitochondrial fusion/fission dynamics remains unclear. Here, we evaluate the effects of laparotomy under 1.4% isoflurane anesthesia for 2 hours on mitochondrial fission/fusion dynamics in the brain of aged mice. Mice in Surgery/Anesthesia group showed unbalanced fission/fusion dynamics, with decreased DISC1 expression and increased expression of Drp1 and Mfn2 in the mitochondrial fraction, leading to excessive mitochondrial fission and disturbed mitochondrial morphogenesis in the hippocampus and prefrontal cortex. In addition, surgical mice presented mitochondrial dysfunction, demonstrated by abnormally activated oxidative stress (increased ROS level, decreased SOD level) and energy deficits (decreased levels of ATP and MMP). Surgery/Anesthesia also decreased the expression of neuronal/synaptic plasticity-related proteins such as PSD-95 and BDNF. Furthermore, Surgery/Anesthesia induced delirium-like behavior in aged mice. In conclusion, Surgery/Anesthesia disturbed mitochondrial fission/fusion dynamics and then impaired mitochondrial function in the brain of aged mice; these effects may be involved in the underlying mechanism of POD.

A comparison of effects of scalp nerve block and local anesthetic infiltration on inflammatory response, hemodynamic response, and postoperative pain in patients undergoing craniotomy for cerebral aneurysms: a randomized controlled trial.

BACKGROUND: The purpose of this study was to compare the effects of scalp nerve block (SNB) and local anesthetic infiltration (LA) with 0.75% ropivacaine on postoperative inflammatory response, intraoperative hemodynamic response, and postoperative pain control in patients undergoing craniotomy. METHODS: Fifty-seven patients were admitted for elective craniotomy for surgical clipping of a cerebral aneurysm. They were randomly divided into three groups: Group S (SNB with 15 mL of 0.75% ropivacaine), group I (LA with 15 mL of 0.75% ropivacaine) and group C (that only received routine intravenous analgesia). Pro-inflammatory cytokine levels in plasma for 72 h postoperatively, hemodynamic response to skin incision, and postoperative pain intensity were measured. RESULTS: The SNB with 0.75% ropivacaine not only decreased IL-6 levels in plasma 6 h after craniotomy but also decreased plasma CRP levels and increased plasma IL-10 levels 12 and 24 h after surgery compared to LA and routine analgesia. There were significant increases in mean arterial pressure 2 and 5 mins after the incision and during dura opening in Groups I and C compared with Group S. Group S had lower postoperative pain intensity, longer duration before the first dose of oxycodone, less consumption of oxycodone and lower incidence of PONV through 48 h postoperatively than Groups I and C. CONCLUSION: Preoperative SNB attenuated inflammatory response to craniotomy for cerebral aneurysms, blunted the hemodynamic response to scalp incision, and controlled postoperative pain better than LA or routine analgesia. TRIAL REGISTRATION: Clinicaltrials.gov NCT03073889 (PI:Xi Yang; date of registration:08/03/2017).

iRNAD: a computational tool for identifying D modification sites in RNA sequence.

MOTIVATION: Dihydrouridine (D) is a common RNA post-transcriptional modification found in eukaryotes, bacteria and a few archaea. The modification can promote the conformational flexibility of individual nucleotide bases. And its levels are increased in cancerous tissues. Therefore, it is necessary to detect D in RNA for further understanding its functional roles. Since wet-experimental techniques for the aim are time-consuming and laborious, it is urgent to develop computational models to identify D modification sites in RNA. RESULTS: We constructed a predictor, called iRNAD, for identifying D modification sites in RNA sequence. In this predictor, the RNA samples derived from five species were encoded by nucleotide chemical property and nucleotide density. Support vector machine was utilized to perform the classification. The final model could produce the overall accuracy of 96.18% with the area under the receiver operating characteristic curve of 0.9839 in jackknife cross-validation test. Furthermore, we performed a series of validations from several aspects and demonstrated the robustness and reliability of the proposed model. AVAILABILITY AND IMPLEMENTATION: A user-friendly web-server called iRNAD can be freely accessible at http://lin-group.cn/server/iRNAD, which will provide convenience and guide to users for further studying D modification.

MicroRNA-181b-5p attenuates early postoperative cognitive dysfunction by suppressing hippocampal neuroinflammation in mice.

BACKGROUND: Postoperative cognitive dysfunction (POCD) is a common complication after surgery and its occurrence is associated with increased morbidity and mortality. However, the pathophysiology of this complication remains largely unknown. Efforts to identify causes of POCD have focused on the hippocampal neuroinflammation. Recently, accumulated evidence indicates that NeurimmiRs, a subset of microRNAs (miRNAs), which modulate both neuronal and immune processes, play an important role in neuroinflammation. However, the impact of NeurimmiRs on POCD has not been investigated. We hypothesized that NeurimmiRs is involved in surgery-induced cognitive impairment in adult mice via mediating hippocampal neuroinflammation. METHODS: MicroRNA(miR)-181b-5p was found to be downregulated in the hippocampi of mice with POCD using microRNA array, which was also verified in vivo in the mouse model of POCD by Quantitative real-time polymerase chain reaction (qPCR). Subsequently, the expression of miR-181b-5p was measured in lipopolysaccharide (LPS) stimulated BV-2 microglial cells and hippocampal tissues of the mice with POCD. Then, loss of function and overexpression studies were performed by transfection with miR-181b-5p mimic/ inhibitor in cultured BV-2 cell lines and intrahippocampal injection of miR-181b-5p agomir before Surgery/Anesthesia, to identify the role of miR-181b-5p in neuroinflammation and cognitive impairments. QPCR, western blot and ELISA were used to determine the expression of proinflammatory mediators. Immunofluorescence staining was applied to evaluate the activation of microglia. Furthermore, we used bioinformatics analysis and dual-luciferase assay to predict and verify the potential target of miR-181b-5p. RESULTS: The results indicated that miR-181b-5p mimic could repress the mRNA and protein expression of proinflammatory mediators, including tumor necrosis factor (TNF)-α, interleukin (IL)-1ß, and monocyte chemoattractant protein (MCP)-1 in LPS-stimulated BV-2 microglial cells, while the miR-181b-5p inhibitor induced upregulation of the above-mentioned proinflammatory factors. Further bioinformatics analysis showed that miR-181b-5p was predicted to potentially target the 3'-untranslated region (UTR) of TNF-α, and binding sites of miR-181b-5p in the 3'-UTR of TNF-α were identified by dual-luciferase assay. Importantly, injecting miR-181b-5p agomir into the hippocampus of mice before surgery, ameliorated the hippocampus-dependent memory, and was accompanied by downregulation of proinflammatory factors expression and reduced microglial activation in the hippocampus of POCD mice. CONCLUSIONS: Collectively, these findings suggest that miR-181b-5p attenuates early POCD by suppressing hippocampal neuroinflammation in mice. They also highlight the importance of studying miRNAs in the context of POCD and identify miR-181b-5p as a novel potential therapeutic target for improving POCD.

Honokiol-Mediated Mitophagy Ameliorates Postoperative Cognitive Impairment Induced by Surgery/Sevoflurane via Inhibiting the Activation of NLRP3 Inflammasome in the Hippocampus.

BACKGROUND: The potential mechanism of postoperative cognitive impairment is still largely unclear. The activation of NLRP3 inflammasome had been reported to be involved in neurodegenerative diseases, including postoperative cognitive change, and is closely related to mitochondrial ROS and mitophagy. Honokiol (HNK) owns multiple organic protective effects. This study is aimed at observing the neuroprotective effect of HNK in postoperative cognitive change and examining the role of HNK in the regulation of mitophagy and the relationship between these effects and NLRP3 inflammasome activation in mice induced by surgery/anesthesia. METHODS: In this study, mice were divided into several groups: control group, surgery group, surgery+HNK group, and surgery+HNK+3-methyladenine (3-MA) group. Hippocampal tissue samples were harvested and used for proinflammatory cytokines, mitochondrial ROS, and malondialdehyde (MDA) assay. The process of mitophagy and the activation of NLRP3 inflammasome were observed by Western blot, immunohistochemistry, and transmission electron microscopy. RESULTS: The results showed that HNK treatment obviously recovered the postoperative decline and enhanced the expressions of LC3-II, Beclin-1, Parkin, and PINK1 at protein levels after surgery/sevoflurane treatment, which are both an autophagy marker and a mitophagy marker. In addition, HNK attenuated mitochondrial structure damage and reduced mtROS and MDA generation, which are closely associated with NLRP3 inflammasome activation. Honokiol-mediated mitophagy inhibited the activation of NLRP3 inflammasome and neuroinflammation in the hippocampus. Using 3-MA, an autophagy inhibitor, the neuroprotective effects of HNK on mitophagy and NLRP3 inflammasome activation were eliminated. CONCLUSION: These results indicated that HNK-mediated mitophagy ameliorates postoperative cognitive impairment induced by surgery/sevoflurane. This neuroprotective effect may be involved in inhibiting the activation of NLRP3 inflammasome and suppressing inflammatory responses in the hippocampus.

MicroRNA-146a protects against cognitive decline induced by surgical trauma by suppressing hippocampal neuroinflammation in mice.

Postoperative cognitive dysfunction (POCD) is a common postoperative complication that is associated with increased morbidity and mortality. However, the neuropathogenesis of this complication remains largely unknown. Neuroinflammation, in particular hippocampal inflammation, contributes to POCD. Recently, increasing evidence has supported the involvement of microRNAs (miRNAs) in the regulation of neuroinflammation in human neurological disorders. In the present study, we investigated the role of miR-146a, a key regulator of the innate immune response, in surgery-induced hippocampal inflammation and cognitive impairment. The expression of miR-146a was measured in BV-2 microglial cells stimulated with lipopolysaccharide (LPS) and hippocampal tissues of mice with POCD. Loss of function and overexpression studies were performed via transfection with miR-146a mimic/inhibitor in cultured BV-2 cell lines and intrahippocampal injection of miR-146a agomir/antagomir before surgery/anesthesia to identify the role of miR-146a in neuroinflammation and cognitive impairment. QPCR, Western blot and ELISA were used to determine the expression levels of downstream adaptor proteins and proinflammatory cytokines. Immunofluorescence staining was applied to evaluate the activation of microglia. Increased expression of miR-146a was observed in BV-2 microglial cells stimulated with LPS and hippocampal tissues of mice with POCD. Modulation of miR-146a expression via transfection of microglia with miR-146a mimic or inhibitor regulated the mRNA and protein expression levels of downstream targets of miR-146a (IRAK1 and TRAF6) as well as the release of proinflammatory cytokines (TNF-α, IL-1ß and IL-6). In addition, overexpression of miR-146a attenuated hippocampus-dependent learning and memory impairment in mice with POCD, which was accompanied by decreased expression of the IRAK1/TRAF6/nuclear factor (NF)-κB pathway and downregulation of microglial activation in the hippocampus. Conversely, knockdown of miR-146a expression may exacerbate hippocampus-dependent learning and memory deficiency and hippocampal inflammation in mice with POCD. Collectively, our findings demonstrate the important role of miR-146a in the neuropathogenesis of POCD and suggest that miR-146a may be a potential therapeutic target for POCD.

SIRT3 activator honokiol ameliorates surgery/anesthesia-induced cognitive decline in mice through anti-oxidative stress and anti-inflammatory in hippocampus.

AIMS: Increasing evidence indicates that neuroinflammatory and oxidative stress play two pivotal roles in cognitive impairment after surgery. Honokiol (HNK), as an activator of Sirtuin3 (SIRT3), has potential multiple biological functions. The aim of these experiments is to evaluate the effects of HNK on surgery/anesthesia-induced cognitive decline in mice. METHODS: Adult C57BL/6 mice received a laparotomy under sevoflurane anesthesia and HNK or SIRT3 inhibitor (3-TYP) treatment. Cognitive function and locomotor activity of mice were evaluated using fear conditioning test and open field test on postoperative 1 and 3 days. Neuronal apoptosis in CA1 and CA3 area of hippocampus was examined using TUNEL assay. And Western blot was applied to measure the expression of pro-inflammatory cytokines and SIRT3/SOD2 signaling-associated proteins in hippocampus. Meanwhile, SIRT3 positive cells were calculated by immunohistochemistry. The mitochondrial membrane potential, malondialdehyde (MDA), and mitochondrial radical oxygen species (mtROS) were detected using standard methods. RESULTS: Honokiol attenuated surgery-induced memory loss and neuronal apoptosis, decreased neuroinflammatory response, and ameliorated oxidative damage in hippocampus. Notably, surgery/anesthesia induced an obviously decrease in hippocampal SIRT3 expression, whereas the HNK increased SIRT3 expression and thus decreased the acetylation of superoxide dismutase 2 (SOD2). However, 3-TYP treatment inhibited the HNK's rescuing effects. CONCLUSIONS: These results suggested that activation of SIRT3 by honokiol may attenuate surgery/anesthesia-induced cognitive impairment in mice through regulation of oxidative stress and neuroinflammatory in hippocampus.

Short-Term Postoperative Cognitive Dysfunction and Inflammatory Response in Patients Undergoing Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy: A Pilot Study.

OBJECTIVES: To assess the association between short-term postoperative cognitive dysfuction (POCD) and inflammtory response in patients undergoing cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC). DESIGN: A prospective cohort study. SETTING: University medical centre. PARTICIPANTS: Fifty-one adult patients who had undergone CRS-HIPEC and twenty control participants. MEASUREMENTS: The inflammatory marker levels in plasma and cognitive function were measured. RESULTS: Twenty (39.2%, 20/51) patients developed POCD at 1 w after CRS-HIPEC. The patients with POCD had higher serum interleukin 1ß (IL-1ß), serum amyloid A (SAA), S100 calcium-binding protein ß (S-100ß), and high mobility group box-1 protein (HMGB-1) levels at 1 and 24 h postoperatively than patients without POCD. There was an association between POCD and the maximum IL-1ß and S-100ß concentrations in serum, which remained following adjustment for age and FBS. CONCLUSION: In this pilot study, perioperative inflammatory marker levels increase significantly after CRS-HIPEC in adult patients, and such elevations are associated with the development of short-term cognitive dysfunction after this complex surgery. These results suggested the need for a larger RCT to replicate and confirm these findings.

Activation of cannabinoid receptor type 2 attenuates surgery-induced cognitive impairment in mice through anti-inflammatory activity.

BACKGROUND: Neuroinflammation plays a major role in postoperative cognitive dysfunction (POCD). Accumulated evidence indicates that cannabinoid receptor type 2 (CB2R) can mediate anti-inflammatory and immunomodulatory effects in part by controlling microglial activity. However, the impact of CB2R on postoperative cognition has not been investigated. We hypothesized that CB2R is involved in surgery-induced cognitive impairment in adult mice. METHODS: Adult C57BL/6 mice were subjected to intramedullary fixation surgery for tibial fracture under isoflurane anesthesia and CB2R agonist (JWH133) or CB2R antagonist (AM630) treatment. The mice were trained 24 h prior to surgery using a fear conditioning protocol and assessed in a novel context on postoperative days 1, 3, and 7 to evaluate cognitive function. Open-field testing was performed to evaluate the locomotor activity of the mice. The expression levels of IL-1ß, TNF-α, MCP-1, and CB2R in the hippocampus and prefrontal cortex were assessed by Western blotting; the expression of microglial marker CD11b in the CA1 area of the hippocampus and medial prefrontal cortex was assessed by immunostaining. RESULTS: The mice displayed no changes in locomotor activity after surgery and drug treatments. The mice exhibited impaired hippocampal-dependent memory accompanied by an increased expression of proinflammatory factors in the hippocampus and prefrontal cortex 1, 3, and 7 days after surgery, while hippocampal-independent memory remained unaffected at the same time points. JWH133 treatment attenuated surgery-induced memory loss, while AM630 treatment aggravated surgery-induced memory loss, paralleled by a decreased or increased expression of proinflammatory factors in the hippocampus and prefrontal cortex. The expression of CB2R in the hippocampus and prefrontal cortex was upregulated following surgery; however, it was downregulated by postoperative treatment with JWH133. Similarly, the expression of CD11b in the CA1 area of the hippocampus and medial prefrontal cortex was upregulated following surgery and downregulated by postoperative treatment with JWH133. CONCLUSIONS: These findings indicate that CB2R may modulate the neuroinflammatory and cognitive impairment in a mouse model of orthopedic surgery, and the activation of CB2R may effectively ameliorate the hippocampal-dependent memory loss of mice in the early postoperative stage.

NeurimmiRs and Postoperative Delirium in Elderly Patients Undergoing Total Hip/Knee Replacement: A Pilot Study.

Objective: Postoperative delirium (POD) is a frequent complication after surgery and its occurrence is associated with poor outcomes. The pathophysiology of this complication is not clear, but identification of risk factors is important for positive postoperative outcomes. The purpose of this study was to investigate the associations between the preoperative expression levels of microRNA (miR)-146a, miR-125b, and miR-181c in cerebrospinal fluid (CSF) and serum and the development and severity of POD. Methods: Forty elderly patients aged 65 years old and older admitted for elective total hip/knee replacement under spinal anesthesia. Preoperatively, baseline cognitive function was assessed using the Mini-Mental State Examination. Each patient was interviewed daily on the first and second postoperative days. Delirium was diagnosed using the Confusion Assessment Method, and delirium severity was measured using the Memorial Delirium Assessment Scale (MDAS). Preoperative serum and CSF miR levels were determined by quantitative real-time PCR (qRT-PCR). Results: POD was detected in 27.5% (11/40) of patients. Up-regulation of miR-146a and miR-181c in CSF and down-regulation of miR-146a in serum were observed preoperatively in patients who developed POD, while patients with and without POD did not differ in serum or CSF levels of miR-125b. Delirious patients had higher CSF/serum ratios of miR-146a and miR-181c levels than non-delirious patients. The lower CSF miR-146a and CSF/serum miR-146a ratios were significantly associated with milder POD severity, represented by a lower MDAS score. Conclusion: The dysregulation of preoperative miR-146a and miR-181c in CSF and serum was associated with the development and severity of POD. These NeurimmiRs might participate in the neuropathogenesis of POD, pending further investigations. Clinical trial registration: this study was registered at ClinicalTrials.gov (NCT02817386).