Intraoperative hypotension associated with postoperative acute kidney injury in hypertension patients undergoing non-cardiac surgery: a retrospective cohort study.

Background: Acute kidney injury (AKI) is a common surgical complication and is associated with intraoperative hypotension. However, the total duration and magnitude of intraoperative hypotension associated with AKI remains unknown. In this study, the causal relationship between the intraoperative arterial pressure and postoperative AKI was investigated among chronic hypertension patients undergoing non-cardiac surgery. Methods: A retrospective cohort study of 6552 hypertension patients undergoing non-cardiac surgery (2011 to 2019) was conducted. The primary outcome was AKI as diagnosed with the Kidney Disease-Improving Global Outcomes criteria and the primary exposure was intraoperative hypotension. Patients' baseline demographics, pre- and post-operative data were harvested and then analyzed with multivariable logistic regression to assess the exposure-outcome relationship. Results: Among 6552 hypertension patients, 579 (8.84%) had postoperative AKI after non-cardiac surgery. The proportions of patients admitted to ICU (3.97 vs. 1.24%, p < 0.001) and experiencing all-cause death (2.76 vs. 0.80%, p < 0.001) were higher in the patients with postoperative AKI. Moreover, the patients with postoperative AKI had longer hospital stays (13.50 vs. 12.00 days, p < 0.001). Intraoperative mean arterial pressure (MAP) < 60 mmHg for >20 min was an independent risk factor of postoperative AKI. Furthermore, MAP <60 mmHg for >10 min was also an independent risk factor of postoperative AKI in patients whose MAP was measured invasively in the subgroup analysis. Conclusions: Our work suggested that MAP < 60 mmHg for >10 min measured invasively or 20 min measured non-invasively during non-cardiac surgery may be the threshold of postoperative AKI development in hypertension patients. This work may serve as a perioperative management guide for chronic hypertension patients. Trial registration: clinical trial number: ChiCTR2100050209 (8/22/2021). http://www.chictr.org.cn/showproj.aspx?proj=132277.

Corrigendum: Xenon attenuated neonatal lipopolysaccharide exposure induced neuronal necroptosis and subsequently improved cognition in juvenile rats.

[This corrects the article DOI: 10.3389/fphar.2022.1002920.].

Perioperative Immunosuppressive Factors during Cancer Surgery: An Updated Review.

Surgical excision of the primary tumor represents the most frequent and curative procedure for solid malignancies. Compelling evidence suggests that, despite its beneficial effects, surgery may impair immunosurveillance by triggering an immunosuppressive inflammatory stress response and favor recurrence by stimulating minimal residual disease. In addition, many factors interfere with the immune effectors before and after cancer procedures, such as malnutrition, anemia, or subsequent transfusion. Thus, the perioperative period plays a key role in determining oncological outcomes and represents a short phase to circumvent anesthetic and surgical deleterious factors by supporting the immune system through the use of synergistic pharmacological and non-pharmacological approaches. In line with this, accumulating studies indicate that anesthetic agents could drive both protumor or antitumor signaling pathways during or after cancer surgery. While preclinical investigations focusing on anesthetics' impact on the behavior of cancer cells are quite convincing, limited clinical trials studying the consequences on survival and recurrences remain inconclusive. Herein, we highlight the main factors occurring during the perioperative period of cancer surgery and their potential impact on immunomodulation and cancer progression. We also discuss patient management prior to and during surgery, taking into consideration the latest advances in the literature.

Dexmedetomidine and argon in combination against ferroptosis through tackling TXNIP-mediated oxidative stress in DCD porcine livers.

Graft availability from donation after circulatory death (DCD) is significantly limited by ischaemia reperfusion (IR) injury. Effective strategies to mitigate IR injury in DCD grafts are essential to improve graft quality and expand the donor pool. In this study, liver grafts from DCD pigs were preserved in the University of Wisconsin (UW) solution saturated with 0.1 nM dexmedetomidine (Dex) and various concentrations of noble gases Argon (Ar) and/or Xenon (Xe) at 4 °C for 24 or 72 h. The combined 50% Ar and Dex provided maximum protection to liver grafts by reducing morphological damage, apoptosis, necroptosis, ferroptosis, hepatocyte glycogen depletion, reticulin framework collapse, iron deposition, and oxidative stress. In vitro, human liver Hep G2 cells were preserved in the UW solution saturated with 0.1 nM Dex and 50% Ar in combination at 4 °C for 24 h, followed by recovery in medium at 37 °C for up to 48 h to mimic clinical IR injury. This treatment significantly increased the expression of anti-oxidative stress proteins by promoting the translocation of thioredoxin-interacting protein (TXNIP) to mitochondria, thereby inhibiting ferroptosis, increasing plasma membrane integrity, and maintaining cell viability.In summary, The combination of 0.1 nM Dex and 50% Ar may be a promising strategy to reduce ferroptosis and other form cell death, and preserve liver grafts.

Dexmedetomidine attenuates inflammatory response and chronic pain following video-assisted thoracoscopic surgery for lung cancer.

BACKGROUND: The objective of the present study was to evaluate the effect of dexmedetomidine administration during video-assisted thoracoscopic surgery for lung cancer on perioperative inflammatory response and chronic post-surgical pain. METHODS: A cohort of 152 patients with lung cancer scheduled for elective video-assisted thoracoscopic surgery participated in this randomized controlled trial. Patients were randomly divided into 2 groups and administered an equivalent volume of dexmedetomidine (n = 63) or normal saline (n = 63). Dexmedetomidine was administered at a dose of 0.6 µg/kg 10 minutes before anesthesia induction and maintained at 0.5 µg/kg/h until 0.5 hours before surgery completed. Anesthesia and postoperative pain management protocols were standardized for both groups. The analysis included vital signs, numerical rating scales of pain, blood inflammatory and oxidative stress biomarkers, pain type and location, patient-controlled intravenous analgesia usage, consumption of general anesthetics and pain rescue medications, as well as complications. RESULTS: The administration of dexmedetomidine resulted in decreased levels of inflammatory cytokines (interleukin-1 beta, interleukin-6, alongside tumor necrosis factor-alpha) and oxidative stress biomarkers (reactive oxygen species alongside malondialdehyde) but elevated levels of interleukin-10 and superoxide dismutase. In addition, the dexmedetomidine group showed lower postoperative numerical rating scale scores, reduced consumption of anesthetics, faster chest-tube removal, fewer patient-controlled intravenous analgesia presses, and shorter postoperative hospital stays. CONCLUSION: The administration of dexmedetomidine effectively attenuated surgical inflammation, oxidative stress, and postoperative pain, thereby promoting patient recovery after lung cancer surgery without increasing the risk of adverse effects or complications.

RNF31-mediated IKKα ubiquitination aggravates inflammation and intestinal injury through regulating NF-κB activation in human and mouse neonates.

AIMS: Neonatal necrotizing enterocolitis (NEC) is a leading cause of intestine inflammatory disease, and macrophage is significantly activated during NEC development. Posttranslational modifications (PTMs) of proteins, particularly ubiquitination, play critical roles in immune response. This study aimed to investigate the effects of ubiquitin-modified proteins on macrophage activation and NEC, and discover novel NEC-related inflammatory proteins. MATERIALS AND METHODS: Proteomic and ubiquitin proteomic analyses of intestinal macrophages in NEC/healthy mouse pups were carried out. In vitro macrophage inflammation model and in vivo NEC mouse model, as well as clinical human samples were used for further verification the inhibitor of nuclear factor-κB kinase α (IKKα) ubiquitination on NEC development through Western blot, immunofluorescence, quantitative real-time polymerase chain reaction (qRT-PCR) and flow cytometry. KEY FINDINGS: We report here that IKKα was a new ubiquitin-modified protein during NEC through ubiquitin proteomics, and RING finger protein 31 (RNF31) acted as an E3 ligase to be involved in IKKα degradation. Inhibition of IKKα ubiquitination and degradation with siRNF31 or proteasome inhibitor decreased nuclear factor-κB (NF-κB) activation, thereby decreasing the expression of pro-inflammatory factors and M1 macrophage polarization, resulting in reliving the severity of NEC. SIGNIFICANCE: Our study suggests the activation of RNF31-IKKα-NF-κB axis triggering NEC development and suppressing RNF31-mediated IKKα degradation may be therapeutic strategies to be developed for NEC treatment.

High intraoperative fluid load associated with prolonged length of hospital stay and complications after non-cardiac surgery in neonates.

Inappropriate perioperative fluid load can lead to postoperative complications and death. This retrospective study was designed to investigate the association between intraoperative fluid load and outcomes in neonates undergoing non-cardiac surgery. From April 2020 to September 2022, 940 neonates who underwent non-cardiac surgery were retrospectively enrolled and their perioperative data were harvested for further analysis. According to recorded intraoperative fluid volumes defined as ml.kg-1 h-1, patients were mandatorily divided into quintile with fluid load as restrictive (quintile 1, Q1), moderately restrictive (Q2), moderate (Q3), moderately liberal (Q4), and liberal (Q5). The primary outcomes were defined as prolonged length of hospital stay (LOS) (postoperative LOS ≥ 14 days), complications beyond prolonged LOS, and 30-day mortality. Secondary outcomes included postoperative complications within 14 days of hospital stay. The intraoperative fluid load was in Q1 of 6.5 (5.3-7.3) (median and IQR); Q2: 9.2 (8.7-9.9); Q3: 12.2 (11.4-13.2); Q4: 16.5 (15.4-18.0); and Q5: 26.5 (22.3-32.2) ml.kg-1 h-1. The odd of prolonged LOS was positively correlated with an increase fluid volume (Q5 quintile: OR 2.602 [95% CI 1.444-4.690], P = 0.001), as well as complications beyond prolonged LOS (Q5: OR 3.322 [95% CI 1.656-6.275], P = 0.001). The overall 30-day mortality rate was increased with high intraoperative fluid load but did not reach to a statistical significance after adjusted with confounders. Furthermore, the highest quintile of fluid load (26.5 ml.kg-1 h-1, IQR [22.3-32.2]) (Q5 quintile) was significantly associated with longer postoperative mechanical ventilation time compared with Q1 (Q5: OR 2.212 [95% CI 1.101-4.445], P = 0.026).    Conclusion: Restrictive intraoperative fluid load had overall better outcomes, whilst high fluid load was significantly associated with prolonged LOS and complications after non-cardiac surgery in neonates.    Trial registration:  Chictr.org.cn Identifier: ChiCTR2200066823 (December 19, 2022). What is Known: • Inappropriate perioperative fluid load can lead to postoperative complications and even death. What is New: • High perioperative fluid load was significantly associated with an increased length of stay after non-cardiac surgery in neonates, whilst low fluid load was consistently related to better postoperative outcomes.

Regulated cell death in hypoxic-ischaemic encephalopathy: recent development and mechanistic overview.

Hypoxic-ischaemic encephalopathy (HIE) in termed infants remains a significant cause of morbidity and mortality worldwide despite the introduction of therapeutic hypothermia. Depending on the cell type, cellular context, metabolic predisposition and insult severity, cell death in the injured immature brain can be highly heterogenous. A continuum of cell death exists in the H/I-injured immature brain. Aside from apoptosis, emerging evidence supports the pathological activation of necroptosis, pyroptosis and ferroptosis as alternative regulated cell death (RCD) in HIE to trigger neuroinflammation and metabolic disturbances in addition to cell loss. Upregulation of autophagy and mitophagy in HIE represents an intrinsic neuroprotective strategy. Molecular crosstalk between RCD pathways implies one RCD mechanism may compensate for the loss of function of another. Moreover, mitochondrion was identified as the signalling "hub" where different RCD pathways converge. The highly-orchestrated nature of RCD makes them promising therapeutic targets. Better understanding of RCD mechanisms and crosstalk between RCD subtypes likely shed light on novel therapy development for HIE. The identification of a potential RCD converging node may open up the opportunity for simultaneous and synergistic inhibition of cell death in the immature brain.

A nomogram for predicting hemorrhagic shock in pediatric patients with multiple trauma.

The timely detection and management of hemorrhagic shock hold paramount importance in clinical practice. This study was designed to establish a nomogram that may facilitate early identification of hemorrhagic shock in pediatric patients with multiple-trauma. A retrospective study was conducted utilizing a cohort comprising 325 pediatric patients diagnosed with multiple-trauma, who received treatment at the Children's Hospital, Zhejiang University School of Medicine, Zhejiang, China. For external validation, an additional cohort of 144 patients from a children's hospital in Taizhou was included. The model's predictor selection was optimized through the application of the Least Absolute Shrinkage and Selection Operator (LASSO) regression. Subsequently, a prediction nomogram was constructed using multivariable logistic regression analysis. The performance and clinical utility of the developed model were comprehensively assessed utilizing various statistical metrics, including Harrell's Concordance Index (C-index), receiver operating characteristic (ROC) curve analysis, calibration curve analysis, and decision curve analysis (DCA). Multivariate logistic regression analysis identified systolic blood pressure (ΔSBP), platelet count, activated partial thromboplastin time (APTT), and injury severity score (ISS) as independent predictors for hemorrhagic shock. The nomogram constructed using these predictors demonstrated robust predictive capabilities, as evidenced by an impressive area under the curve (AUC) value of 0.963. The model's goodness-of-fit was assessed using the Hosmer-Lemeshow test (χ2 = 10.023, P = 0.209). Furthermore, decision curve analysis revealed significantly improved net benefits with the model. External validation further confirmed the reliability of the proposed predictive nomogram. This study successfully developed a nomogram for predicting the occurrence of hemorrhagic shock in pediatric patients with multiple trauma. This nomogram may serve as an accurate and effective tool for timely and efficient management of children with multiple trauma.

Dexmedetomidine Attenuates Inflammation in Elderly Patients Following Major Hepatobiliary and Pancreatic Surgery: A Randomized Clinical Trial.

Background: Dexmedetomidine (Dex) may have anti-inflammatory properties and potentially reduce the incidence of postoperative organ injury. Objective: To investigate whether Dex protects pulmonary and renal function via its anti-inflammatory effects in elderly patients undergoing prolonged major hepatobiliary and pancreatic surgery. Design and Setting: Between October 2019 and December 2020, this randomized controlled trial was carried out at a tertiary hospital in Chongqing, China. Patients: 86 patients aged 60-75 who underwent long-duration (> 4 hrs) hepatobiliary and pancreatic surgery without significant comorbidities were enrolled and randomly assigned into two groups at a 1:1 ratio. Interventions: Patients were given either Dex or an equivalent volume of 0.9% saline (Placebo) with a loading dose of 1 µg kg-1 for 10 min, followed by 0.5 µg kg-1 hr-1 for maintenance until the end of surgery. Main Outcome Measures: The changes in serum concentrations of interleukin-6 (IL-6) and tumour necrosis factor-α (TNF-α) were primary outcomes. Results: At one hour postoperatively, serum IL-6 displayed a nine-fold increase (P<0.05) in the Placebo group. Administration of Dex decreased IL-6 to 278.09 ± 45.43 pg/mL (95% CI: 187.75 to 368.43) compared to the Placebo group (P=0.019; 432.16 ± 45.43 pg/mL, 95% CI: 341.82 to 522.50). However, no significant differences in TNF-α were observed between the two groups. The incidence of postoperative acute kidney injury was twice as high in the Placebo group (9.30%) compared to the Dex group (4.65%), and the incidence of postoperative acute lung injury was 23.26% in the Dex group, lower than that in the Placebo group (30.23%), although there was no statistical significance between the two groups. Conclusion: Dex administration in elderly patients undergoing major hepatobiliary and pancreatic surgery reduces inflammation and potentially protects kidneys and lungs. Registration: Chinese Clinical Trials Registry, identifier: ChiCTR1900024162, on 28 June 2019.

Correction: Duan et al. Methionine Restriction Prevents Lipopolysaccharide-Induced Acute Lung Injury via Modulating CSE/H2S Pathway. Nutrients 2022, 14, 322.

In the original publication [...].

Oxytocin attenuates neuroinflammation-induced anxiety through restoration of excitation and inhibition balance in the anterior cingulate cortex in mice.

BACKGROUND: Accumulative evidence suggested that the oxytocin system plays a role in socio-emotional disorders, although its role in neuroinflammation-induced anxiety remains unclear. METHOD: In the present study, anxiety-like behavior was induced in cohorts of animals through repeated lipopolysaccharide (LPS, 0.5 mg/kg, daily, Escherichia coli O55:B5) i.p. injections for seven consecutive days. These different cohorts were subsequently used for anxiety-like behavior assessment with open field test, elevated plus maze, and novelty-suppressed feeding test or for electrophysiology (EEG) recordings of miniature excitatory postsynaptic currents (mEPSCs), miniature inhibitory postsynaptic currents (mIPSCs), or local field potential (LFP) in vivo or ex vivo settings. Samples of the anterior cingulate cortex (ACC) from some cohorts were harvested to conduct immunostaining or western blotting analysis of oxytocin, oxytocin receptor, CamkII, GABA, vGAT, vGLUT2, and c-fos. The dendritic spine density was assessed by Golgi-Cox staining. RESULTS: Repeated LPS injections induced anxiety-like behavior with concurrent decreases of oxytocin, vGLUT2, mEPSC, dendritic spine, c-fos, membrane excitability, and EEG beta and gamma oscillations, but increased oxytocin receptor and vGAT expressions in the ACC; all these changes were ameliorated by oxytocin intranasal or local brain (via cannula) administration. CONCLUSION: Taken together, our data suggested that oxytocin system may be a therapeutic target for developing treatment to tackle neuroinflammation-induced anxiety.

Dexmedetomidine use during orthotopic liver transplantation surgery on early allograft dysfunction: A randomized controlled trial.

BACKGROUND: Previous studies have shown a protective effect of dexmedetomidine use in kidney transplantation. In contrast, it is not known whether intraoperative administration of dexmedetomidine can reduce early allograft dysfunction incidence following liver transplantation. OBJECTIVE: To investigate the effect of dexmedetomidine use during surgery on early allograft dysfunction following orthotopic liver transplantation (OLT). STUDY DESIGN: This is a single-center, double-blinded, placebo-controlled randomized clinical trial. 330 adult patients undergoing orthotopic liver transplantation were enrolled from Jan 14th, 2019 to May 22nd, 2022. Patients received dexmedetomidine or normal saline during surgery. 1 year follow-ups were recorded. METHODS: Patients were randomized to two groups receiving either dexmedetomidine or normal saline intraoperatively. For patients in the dexmedetomidine group, a loading dose (1 µg/kg over 10 min) of dexmedetomidine was given after induction of anesthesia followed by a continuous infusion (0.5 µg/kg /h) until the end of surgery. For patients in the normal saline group, an equal volume loading dose of 0.9% saline was given after the induction of anesthesia followed by an equal volume continuous infusion until the end of surgery. The primary outcome was early allograft dysfunction. Secondary outcomes included primary graft non-function, acute kidney injury and acute lung injury/ acute respiratory distress syndrome. RESULTS: Of 330 patients included in the intention-to-treat analysis, 165 were in the dexmedetomidine group (mean [SD] age, 49 [10] years; 117 [70.9%] men), and 165 were in the normal saline group (mean SD age, 49 [9] years; 118 [74%] men). 39 (24.4%) patients in the dexmedetomidine group and 31 (19.4%) in normal saline group developed early allograft dysfunction and the difference was statistically insignificant (P=0.28). Secondary outcomes including primary graft non-function and acute kidney injury was similar between the two groups. CONCLUSION: Intraoperative administration of dexmedetomidine did not reduce early allograft dysfunction rate after orthotopic liver transplantation.

Siglec-F+ neutrophils in the spleen induce immunosuppression following acute infection.

Background: The mechanisms underlying the increased mortality of secondary infections during the immunosuppressive phase of sepsis remain elusive. Objectives: We sought to investigate the role of Siglec-F+ neutrophils on splenic T lymphocytes in the immunosuppressed phase of sepsis and on secondary infection in PICS mice, and to elucidate the underlying mechanisms. Methods: We established a mouse model of sepsis-induced immunosuppression followed by secondary infection with LPS or E. coli. The main manifestation of immunosuppression is the functional exhaustion of splenic T lymphocytes. Treg depletion reagent Anti-IL-2, IL-10 blocker Anti-IL-10R, macrophage depletion reagent Liposomes, neutrophil depletion reagent Anti-Ly6G, neutrophil migration inhibitor SB225002, Siglec-F depletion reagent Anti-Siglec-F are all used on PICS mice. The function of neutrophil subsets was investigated by adoptive transplantation and the experiments in vitro. Results: Compared to other organs, we observed a significant reduction in pro-inflammatory cytokines in the spleen, accompanied by a marked increase in IL-10 production, primarily by infiltrating neutrophils. These infiltrating neutrophils in the spleen during the immunosuppressive phase of sepsis undergo phenotypic change in the local microenvironment, exhibiting high expression of neutrophil biomarkers such as Siglec-F, Ly6G, and Siglec-E. Depletion of neutrophils or specifically targeting Siglec-F leads to enhance the function of T lymphocytes and a notable improvement in the survival of mice with secondary infections. Conclusions: We identified Siglec-F+ neutrophils as the primary producers of IL-10, which significantly contributed to T lymphocyte suppression represents a novel finding with potential therapeutic implications.

Dexmedetomidine attenuates lipopolysaccharide-induced renal cell fibrotic phenotypic changes by inhibiting necroinflammation via activating α2-adrenoceptor: A combined randomised animal and in vitro study.

BACKGROUND: Acute kidney injury (AKI) was reported to be one of the initiators of chronic kidney disease (CKD) development. Necroinflammation may contribute to the progression from AKI to CKD. Dexmedetomidine (Dex), a highly selective α2-adrenoreceptor (AR) agonist, has cytoprotective and "anti-" inflammation effects. This study was designed to investigate the anti-fibrotic properties of Dex in sepsis models. METHODS: C57BL/6 mice were randomly treated with an i.p. injection of lipopolysaccharides (LPS) (10 mg/kg) alone, LPS with Dex (25 µg/kg), or LPS, Dex and Atipamezole (Atip, an α2-adrenoreceptor antagonist) (500 µg/kg) (n=5/group). Human proximal tubular epithelial cells (HK2) were also cultured and then exposed to LPS (1 µg/ml) alone, LPS and Dex (1 µM), transforming growth factor-beta 1 (TGF-ß1) (5 ng/ml) alone, TGF-ß1 and Dex, with or without Atip (100 µM) in culture media. Epithelial-mesenchymal transition (EMT), cell necrosis, necroptosis and pyroptosis, and c-Jun N-terminal kinase (JNK) phosphorylation were then determined. RESULTS: Dex treatment significantly alleviated LPS-induced AKI, myofibroblast activation, NLRP3 inflammasome activation, and necroptosis in mice. Atip counteracted its protective effects. Dex attenuated LPS or TGF-ß1 induced EMT and also prevented necrosis, necroptosis, and pyroptosis in response to LPS stimulation in the HK2 cells. The anti-EMT effects of Dex were associated with JNK phosphorylation. CONCLUSIONS: Dex reduced EMT following LPS stimulation whilst simultaneously inhibiting pyroptosis and necroptosis via α2-AR activation in the renal tubular cells. The "anti-fibrotic" and cytoprotective properties and its clinical use of Dex need to be further studied.

Clinical practice guidelines for prevention and treatment of postoperative gastrointestinal disorder with Integrated Traditional Chinese and Western Medicine (2023).

Postoperative gastrointestinal disorder (POGD) was a common complication after surgery under anesthesia. Strategies in combination with Traditional Chinese Medicine and Western medicine showed some distinct effects but standardized clinical practice guidelines were not available. Thus, a multidisciplinary expert team from various professional bodies including the Perioperative and Anesthesia Professional Committees of the Chinese Association of Integrative Medicine (CAIM), jointly with Gansu Province Clinical Research Center of Integrative Anesthesiology/Anesthesia and Pain Medical Center of Gansu Provincial Hospital of Traditional Chinese Medicine and WHO Collaborating Center for Guideline Implementation and Knowledge Translation/Chinese Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) Center/Gansu Provincial Center for Medical Guideline Industry Technology/Evidence-based Medicine Center of Lanzhou University, was established to develop evidence-based guidelines. Clinical questions (7 background and 12 clinical questions) were identified through literature reviews and expert consensus meetings. Based on systematic reviews/meta-analyses, evidence quality was analyzed and the advantages and disadvantages of interventional measures were weighed with input from patients' preferences. Finally, 20 recommendations were developed through the Delphi-based consensus meetings. These recommendations included disease definitions, etiologies, pathogenesis, syndrome differentiation, diagnosis, and perioperative prevention and treatment.

Astrocytic phagocytosis in the medial prefrontal cortex jeopardises postoperative memory consolidation in mice.

Memory impairment is one of the main characteristics of postoperative cognitive dysfunction. It remains elusive how postoperative pathological changes of the brain link to the memory impairment. The clinical setting of perioperation was mimicked via partial hepatectomy under sevoflurane anaesthesia together with preoperative restraint stress (Hep-Sev-stress) in mice. Memory changes were assessed with fear conditioning. The medial prefrontal cortex (mPFC)-dorsal hippocampus connectivity was evaluated with injecting neurotracer 28 days before surgery. Astrocytic activation was limited via injecting AAV-GFAP-hM4Di-eGFP into the mPFC. Astrocytic and microglial phagocytosis of synapses were visualised with co-labelling hippocampal neuronal axon terminals with PSD-95 and S100ß or Iba1. Neuroinflammation and oxidative stress status were also detected. Hep-Sev-stress impaired the memory consolidation (mean [standard error], 49.91 [2.55]% vs. 35.40 [3.97]% in the contextual memory, p = 0.007; 40.72 [2.78]% vs. 27.77 [2.22]% in cued memory, p = 0.002) and the cued memory retrieval (39.00 [3.08]% vs. 24.11 [2.06]%, p = 0.001) in mice when compared with these in the naïve controls. Hep-Sev-stress damaged the connectivity from the dorsal hippocampus to mPFC but not from the mPFC to the dorsal hippocampus and increased the astrocytic but not microglial phagocytosis of hippocampal neuronal axon terminals in the mPFC. The intervention also induced neuroinflammation and oxidative stress in the dorsal hippocampus and the mPFC in a regional-dependent manner. Limiting astrocyte activation in the mPFC alleviated memory consolidation impairment induced by Hep-Sev-stress. Postoperative memory consolidation was impaired due to astrocytic phagocytosis-induced connectivity injury from the dorsal hippocampus to the medial prefrontal cortex.

Cerebellar Purkinje cell firing promotes conscious recovery from anesthesia state through coordinating neuronal communications with motor cortex.

Background: The neurobiological basis of gaining consciousness from unconscious state induced by anesthetics remains unknown. This study was designed to investigate the involvement of the cerebello-thalamus-motor cortical loop mediating consciousness transitions from the loss of consciousness (LOC) induced by an inhalational anesthetic sevoflurane in mice. Methods: The neural tracing and fMRI together with opto-chemogenetic manipulation were used to investigate the potential link among cerebello-thalamus-motor cortical brain regions. The fiber photometry of calcium and neurotransmitters, including glutamate (Glu), γ-aminobutyric acid (GABA) and norepinephrine (NE), were monitored from the motor cortex (M1) and the 5th lobule of the cerebellar vermis (5Cb) during unconsciousness induced by sevoflurane and gaining consciousness after sevoflurane exposure. Cerebellar Purkinje cells were optogenetically manipulated to investigate their influence on consciousness transitions during and after sevoflurane exposure. Results: Activation of 5Cb Purkinje cells increased the Ca2+ flux in the M1 CaMKIIα+ neurons, but this increment was significantly reduced by inactivation of posterior and parafascicular thalamic nucleus. The 5Cb and M1 exhibited concerted calcium flux, and glutamate and GABA release during transitions from wakefulness, loss of consciousness, burst suppression to conscious recovery. Ca2+ flux and Glu release in the M1, but not in the 5Cb, showed a strong synchronization with the EEG burst suppression, particularly, in the gamma-band range. In contrast, the Glu, GABA and NE release and Ca2+ oscillations were coherent with the EEG gamma band activity only in the 5Cb during the pre-recovery of consciousness period. The optogenetic activation of Purkinje cells during burst suppression significantly facilitated emergence from anesthesia while the optogenetic inhibition prolonged the time to gaining consciousness. Conclusions: Our data indicate that cerebellar neuronal communication integrated with motor cortex through thalamus promotes consciousness recovery from anesthesia which may likely serve as arousal regulation.

Lack of S1PR2 in Macrophage Ameliorates Sepsis-associated Lung Injury through Inducing IL-33-mediated Type 2 Immunity.

The function of type 2 immunity and mechanisms underlying the initiation of type 2 immunity after sepsis-induced lung injury remain unclear. Sphingosine-1-phosphate receptor 2 (S1PR2) has been demonstrated to modulate type 2 immunity in the context of asthma and pulmonary fibrosis. Thus, this study aims to investigate the role of type 2 immunity and whether and how S1PR2 regulates type 2 immunity in sepsis. Peripheral type 2 immune responses in patients with sepsis and healthy control subjects were assessed. The impact of S1PR2 on type 2 immunity in patients with sepsis and in a murine model of sepsis was further investigated. The type 2 innate immune responses were significantly increased in the circulation of patients 24 hours after sepsis, which was positively related to clinical complications and negatively correlated with S1PR2 mRNA expression. Animal studies showed that genetic deletion or pharmacological inhibition of S1PR2 induced type 2 innate immunity accumulation in the post-septic lungs. Mechanistically, S1PR2 deficiency promoted macrophage-derived interleukin (IL)-33 increase and the associated type 2 response in the lung. Furthermore, S1PR2-regulated IL-33 from macrophages mitigated lung injury after sepsis in mice. In conclusion, a lack of S1PR2 modulates the type 2 immune response by upregulating IL-33 release from macrophages and alleviates sepsis-induced lung injury. Targeting S1PR2 may have potential therapeutic value for sepsis treatment.

Increased A1 astrocyte activation-driven hippocampal neural network abnormality mediates delirium-like behavior in aged mice undergoing cardiac surgery.

Delirium is the most common neurological complication after cardiac surgery with adverse impacts on surgical outcomes. Advanced age is an independent risk factor for delirium occurrence but its underlying mechanisms are not fully understood. Although increased A1 astrocytes and abnormal hippocampal networks are involved in neurodegenerative diseases, whether A1 astrocytes and hippocampal network changes are involved in the delirium-like behavior of aged mice remains unknown. In the present study, a mice model of myocardial ischemia-reperfusion mimicking cardiac surgery and various assessments were used to investigate the different susceptibility of the occurrence of delirium-like behavior between young and aged mice and the underlying mechanisms. The results showed that surgery significantly increased hippocampal A1 astrocyte activation in aged compared to young mice. The high neuroinflammatory state induced by surgery resulted in glutamate accumulation in the extrasynaptic space, which subsequently decreased the excitability of pyramidal neurons and increased the PV interneurons inhibition through enhancing N-methyl-D-aspartate receptors' tonic currents in the hippocampus. These further induced the abnormal activities of the hippocampal neural networks and consequently contributed to delirium-like behavior in aged mice. Notably, the intraperitoneal administration of exendin-4, a glucagon-like peptide-1 receptor agonist, downregulated A1 astrocyte activation and alleviated delirium-like behavior in aged mice, while IL-1α, TNF-α, and C1q in combination administered intracerebroventricularly upregulated A1 astrocyte activation and induced delirium-like behavior in young mice. Therefore, our study suggested that cardiac surgery increased A1 astrocyte activation which subsequently impaired the hippocampal neural networks and triggered delirium development.