Current Perspectives on Postoperative Cognitive Dysfunction in the Ageing Population

MicroRNA-669f-5p targeting deoxycytidinephosphate deaminase contributes to sevoflurane-induced cognitive impairments in aged mice via the TLR2/4-MyD88-NF-κB pathway

BACKGROUND

Postoperative cognitive dysfunction (POCD) is a common complication associated with sevoflurane anaesthesia in the aged population. MicroRNAs have been implicated in sevoflurane-induced cognitive deficits; however, the role and underlying mechanism of microRNA (miR)-669f-5p remain unclear.

METHODS

Eighteen-month-old mice and mouse hippocampal neurons (HT22) were exposed to sevoflurane. Cognitive function was assessed using the Morris water maze test. Neuroapoptosis and cellular proliferation were evaluated by terminal-deoxynucleotidyl transferase-mediated nick end-labelling staining and Cell Counting Kit-8 assays, respectively. The downstream molecular mechanisms of miR-669f-5p were investigated using bioinformatics analysis, western blotting, quantitative real-time polymerase chain reaction, immunofluorescence and dual-luciferase reporter assays.

RESULTS

Bioinformatics analysis of the Gene Expression Omnibus database revealed upregulation of miR-669f-5p in hippocampal tissue from mice with POCD. Inhibition of miR-669f-5p substantially improved sevoflurane-induced cognitive impairment in aged mice. Deoxycytidinephosphate deaminase (Dctd) was identified as a direct target of miR-669f-5p. Overexpression of Dctd reversed the effects of miR-669f-5p mimics on apoptosis and proliferation in HT22 cells and suppressed activation of the TLR2/4-MyD88-NF-κB signalling pathway. Moreover, Dctd overexpression ameliorated sevoflurane-induced cognitive impairment in aged mice.

CONCLUSION

MicroRNA-669f-5p contributes to sevoflurane-induced cognitive impairment in aged mice by targeting Dctd and activating the TLR2/4-MyD88-NF-κB pathway. These findings provide new insights into potential therapeutic strategies for anaesthesia-related POCD.

Actions of dexmedetomidine in regulating NLRP3 in postoperative cognitive dysfunction in aged mice via the autophagy-lysosome pathway

BACKGROUND AND PURPOSE

Autophagy-lysosomal pathway dysfunction leads to postoperative cognitive dysfunction (POCD). Dexmedetomidine (Dex) improves POCD, and we probed the effects of Dex on autophagy-lysosomal pathway dysfunction in a POCD model.

EXPERIMENTAL APPROACH

A POCD mouse model was established and intraperitoneally injected with Dex. Cognitive function was evaluated by Morris water maze/open field test/novel object recognition assay. Levels of neurotransmitters/inflammatory cytokines in hippocampus, and NLRP3/ASC/Cleaved Caspase-1 proteins were determined by ELISA/Western blot. NLRP3 inflammasome-mediated microglial activation/astrocyte A1 differentiation in the hippocampal CA1 region were assessed by immunofluorescence assay. BV-2 cells were treated with lipopolysaccharide (LPS) and Dex and/or the NLRP3 inflammasome activator Nigericin, and transfected with si-TFEB for co-culture with primary reactive astrocytes (RAs) to verify the function of Dex in vitro.

KEY RESULTS

Dex alleviated cognitive dysfunction in POCD mice and repressed NLRP3 inflammasome-mediated microglial activation and astrocyte A1 differentiation. NLRP3 inflammasome activation partially reversed the protective effect of Dex on the POCD condition. In vitro experiments verified the inhibitory properties of Dex on microglial activation and astrocyte A1 differentiation. Dex induces TFEB nuclear translocation, microglial autophagy and lysosomal biogenesis. By activating the autophagy-lysosome pathway, Dex regulated NLRP3 inflammasome-mediated microglial activation, inhibited astrocyte A1 differentiation and alleviated POCD in vivo.

CONCLUSION AND IMPLICATIONS

Dex regulates NLRP3 inflammasome-mediated hippocampal microglial activation by promoting TFEB nuclear translocation and activating the autophagy-lysosome pathway and inhibits astrocyte A1 differentiation, thereby alleviating POCD.

Effect of preoperative oral carbohydrate on postoperative delirium in elderly patients undergoing lower extremity orthopedic surgery: a prospective randomized trial

BACKGROUND

Postoperative metabolic disorders and inflammatory responses are closely associated with postoperative delirium (POD). Preoperative oral carbohydrate intake can alleviate postoperative insulin resistance and the inflammatory response. This study aimed to evaluate the effects of preoperative oral carbohydrate intake on the incidence of POD in older patients undergoing lower limb orthopedic surgery.

METHODS

Eighty patients were randomly assigned to oral intake of 200 mL carbohydrate solution (Group CHO) 2 h before surgery or fasting for 8 h before surgery (Group C). The primary outcome was the incidence of POD. Fasting plasma glucose, interleukin (IL)-6, and C-reactive protein (CRP) levels were assessed before surgery and 1, 3, and 5 days after surgery (D1, D3, and D5).

RESULTS

The incidence of POD in Group CHO was lower than that in Group C (P = 0.005). Blood glucose, IL-6 and CRP levels of Group CHO were significantly lower than those of Group C on D1 and D3 (P < 0.05).

CONCLUSIONS

Preoperative oral carbohydrate intake can reduce the incidence of POD in older patients by ameliorating postoperative metabolic disorders and reducing inflammatory responses.

TRIAL REGISTRATION

ChiCTR2300070154, Date of registration: 03/04/2023.

Evolving Concepts of Pain Management in Elderly Patients

PURPOSE OF REVIEW

The elderly population typically suffer from a variety of diseases that mostly reflect the degenerative changes linked with the aging process. These diseases may be exacerbated by acute pain or by an abrupt aggravation of previously stable chronic pain.

RECENT FINDINGS

Physical and psychological changes associated with aging may influence one's experience of pain and, as a result, the severity of pain. Pain treatment in the elderly can be complex and is often a budgetary burden on the nation's health care system. These difficulties arise, in part, because of unanticipated pharmacodynamics, changed pharmacokinetics, and polypharmacy interactions. Therefore, it is critical to integrate a multidisciplinary team to develop a management strategy that incorporates medical, psychological, and surgical methods to control persistent pain conditions. It is in this critical process that pain prediction models can be of great use. The purpose of pain prediction models for the elderly is the use of mathematical models to predict the occurrence and intensity of pain and pain-related conditions. These mathematical models employ a vast quantity of data to ascertain the many risk factors for the development of pain problems in the elderly, whether said risks are adjustable or not. These models will pave the way for more informed medical decision making that are based on the findings of thousands of patients who have previously experienced the same illness and related pain conditions. However, future additional research needs to be undertaken to build prediction models that are not constrained by substantial legal or methodological limitations.

The Association of Cerebral Oxygen Desaturation with Postoperative Cognitive Dysfunction in Older Patients: A Review

Postoperative cognitive dysfunction (POCD) is a neurological complication associated with surgery and anesthesia that is commonly observed in older patients, and it can significantly affect patient prognosis and survival. Therefore, predicting and preventing POCD is important. Regional cerebral oxygen saturation (rSO2) reflects cerebral perfusion and oxygenation, and decreased intraoperative cerebral oxygen saturation has been reported to increase the risk of POCD. In this review, we elucidated the important relationship between the decline in rSO2 and risk of POCD in older patients. We also emphasized the importance of monitoring rSO2 during surgery to predict and prevent adverse perioperative cognitive outcomes. The findings reveal that incorporating intraoperative rSO2 monitoring into clinical practice has potential benefits, such as protecting cognitive function, reducing perioperative adverse outcomes, and ultimately improving the overall quality of life of older adults.

Efficacy of intraoperative subanesthetic dose of ketamine/esketamine in preventing postoperative cognitive dysfunction: a systematic review and meta-analysis

Background

Postoperative cognitive dysfunction (POCD) is a common complication after anesthesia surgery, especially in older people, that can persist weeks or months after surgery as a short-term impairment of cognitive abilities, or even for a prolonged duration over years, potentially progressing into permanent cognitive dysfunction. However, the pathogenesis of POCD is not fully understood, and therefore an optimal solution for preventing POCD has yet to be established. Some studies have shown that intraoperative ketamine/esketamine reduces the incidence of POCD, but this remains controversial.

Objectives

We evaluated the effect of intraoperative subanesthetic doses of ketamine/esketamine versus no intervention in adults undergoing general anesthesia surgery on the incidence of POCD.

Data Sources

We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and searched the PubMed, Embase, Ovid, Cochrane, Scopus, and Web of Science databases for the MeSH terms 'ketamine', 'esketamine', and 'Postoperative Cognitive Complications' from database inception to 25 June 2023.

Results

We found no statistically significant difference in the incidence of POCD within 7 days for intraoperative subanesthetic dose of ketamine/esketamine compared with the control group [relative risk (RR) = 0.57, 95% confidence interval (CI): 0.32, 1.01], and the results from the subgroup analysis based on age (>60 years) also revealed that the difference was not statistically significant (RR = 0.49, 95% CI: 0.23, 1.04).

Conclusion

Compared with controls, intraoperative subanesthetic dose of ketamine/esketamine has no advantage in preventing POCD in patients, or in elderly patients. This study provides reference data for POCD research and clinical drug intervention strategies.

Registration

Prospective Register of Systematic Reviews (PROSPERO; registration number CRD42023401159).

Histone deacetylase 9 plays a role in sevoflurane-induced neuronal differentiation inhibition by inactivating cAMP-response element binding protein transcription and inhibiting the expression of neurotrophin-3

Postoperative cognitive decline (POCD) is a common and serious complication following anesthesia and surgery; however, the precise mechanisms of POCD remain unclear. Our previous research showed that sevoflurane impairs adult hippocampal neurogenesis (AHN) and thus cognitive function in the aged brain by affecting neurotrophin-3 (NT-3) expression; however, the signaling mechanism involved remains unexplored. In this study, we found a dramatic decrease in the proportion of differentiated neurons with increasing concentrations of sevoflurane, and the inhibition of neural stem cell differentiation was partially reversed after the administration of exogenous NT-3. Understanding the molecular underpinnings by which sevoflurane affects NT-3 is key to counteracting cognitive dysfunction. Here, we report that sevoflurane administration for 2 days resulted in upregulation of histone deacetylase 9 (HDAC9) expression, which led to transcriptional inactivation of cAMP-response element binding protein (CREB). Due to the colocalization of HDAC9 and CREB within cells, this may be related to the interaction between HDAC9 and CREB. Anyway, this ultimately led to reduced NT-3 expression and inhibition of neural stem cell differentiation. Furthermore, knockdown of HDAC9 rescued the transcriptional activation of CREB after sevoflurane exposure, while reversing the downregulation of NT-3 expression and inhibition of neural stem cell differentiation. In summary, this study identifies a unique mechanism by which sevoflurane can inhibit CREB transcription through HDAC9, and this process reduces NT-3 levels and ultimately inhibits neuronal differentiation. This finding may reveal a new strategy to prevent sevoflurane-induced neuronal dysfunction.

Effects of permissive hypercapnia on intraoperative cerebral oxygenation and early postoperative cognitive function in older patients with non-acute fragile brain function undergoing laparoscopic colorectal surgery: protocol study

BACKGROUND

Perioperative brain protection in older patients has been the focus of research recently; meanwhile, exploring the relationship between regional cerebral oxygen saturation (rSO2) and brain function in the perioperative period has been an emerging and challenging area-the difficulties related to the real-time monitoring of rSO2 and the choice of feasible interventions. As an advanced instrument for intraoperative rSO2 monitoring, the clinical application of near-infrared spectrum (NIRS) cerebral oxygen monitoring has gradually increased in popularity and is being recognized for its beneficial clinical outcomes in patients undergoing cardiac and noncardiac surgery. In addition, although sufficient evidence to support this hypothesis is still lacking, the effect of permissive hypercapnia (PHC) on rSO2 has expanded from basic research to clinical exploration. Therefore, monitoring intraoperative rSO2 in older patients with NIRS technology and exploring possible interventions that may change rSO2 and even improve postoperative cognitive performance is significant and clinically valuable.

METHODS

This study is a single-center randomized controlled trial (RCT). 76 older patients are enrolled as subjects. Patients who meet the screening criteria will be randomly assigned 1:1 to the control and intervention groups. PHC-based mechanical ventilation will be regarded as an intervention. The primary outcome is the absolute change in the percent change in rSO2 from baseline to the completion of surgery in the intervention and control groups. Secondary outcomes mainly include observations of intraoperative cerebral oxygenation and metabolism, markers of brain injury, and assessments of patients' cognitive function using scale through postoperative follow-up.

DISCUSSION

The findings of this RCT will reveal the effect of PHC on intraoperative rSO2 in older patients with nonacute fragile brain function (NFBF) and the approximate trends over time, and differences in postoperative cognitive function outcomes. We anticipate that the trial results will inform clinical policy decision-makers in clinical practice, enhance the management of intraoperative cerebral oxygen monitoring in older patients with comorbid NFBF, and provide guidance for clinical brain protection and improved postoperative cognitive function outcomes.

TRIAL REGISTRATION

ChiCTR, ChiCTR2200062093, Registered 9/15/2022.

Effects of anesthetic adjunctive agents on postoperative cognitive dysfunction in elderly patients undergoing noncardiac surgery: A Bayesian network meta-analysis

BACKGROUND

Elderly patients are prone to postoperative cognitive dysfunction (POCD). The comparison of the effects of anesthetic adjuvant drugs on POCD in elderly patients undergoing noncardiac surgery remains controversial.

METHODS

The final search took place on June 10, 2023. Randomized controlled trials including ketamine, ulinastatin, dexmedetomidine, parecoxib, and midazolam on the prevention and treatment of POCD in elderly undergoing noncardiac surgery were collected. A Bayesian network meta-analysis was performed to quantitatively combine the evidence.

RESULTS

A total of 35 randomized trials were finally included in this systematic review, and the overall risk of bias is Allocation concealment. These anesthetic adjuvant drugs did not show significant differences in preventing POCD on postoperative days 1 and 7 compared with each other, but ulinastatin may be more effective in preventing POCD than dexmedetomidine [odds ratio (OR) = 0.28, 95% confidence interval (CI) = (0.10, 0.71)] and parecoxib [OR = 0.3, 95% CI = (0.10, 0.82 on postoperative day 3. The efficiency ranking results also find that ulinastatin and ketamine might provide better effects regarding POCD prevention.

CONCLUSIONS

Ketamine and ulinastatin might have better effects in preventing POCD in elderly patients undergoing noncardiac surgery. Our meta-analysis provided evidence for the use of ulinastatin and ketamine in the prevention of POCD in elderly patients undergoing noncardiac surgery.

Sevoflurane upregulates neuron death process-related Ddit4 expression by NMDAR in the hippocampus

Postoperative cognitive dysfunction (POCD) is a serious and common complication induced by anesthesia and surgery. Neuronal apoptosis induced by general anesthetic neurotoxicity is a high-risk factor. However, a comprehensive analysis of general anesthesia-regulated gene expression patterns and further research on molecular mechanisms are lacking. Here, we performed bioinformatics analysis of gene expression in the hippocampus of aged rats that received sevoflurane anesthesia in GSE139220 from the GEO database, found a total of 226 differentially expressed genes (DEGs) and investigated hub genes according to the number of biological processes in which the genes were enriched and performed screening by 12 algorithms with cytoHubba in Cytoscape. Among the screened hub genes, Agt, Cdkn1a, Ddit4, and Rhob are related to the neuronal death process. We further confirmed that these genes, especially Ddit4, were upregulated in the hippocampus of aged mice that received sevoflurane anesthesia. NMDAR, the core target receptor of sevoflurane, rather than GABAAR, mediates the sevoflurane regulation of DDIT4 expression. Our study screened sevoflurane-regulated DEGs and focused on the neuronal death process to reveal DDIT4 as a potential target mediated by NMDAR, which may provide a new target for the treatment of sevoflurane neurotoxicity.

Effectiveness of dexmedetomidine on postoperative cognitive dysfunction in elderly patients with fracture: A systematic review

BACKGROUND

Previous studies have explored the effectiveness of dexmedetomidine on postoperative cognitive dysfunction (POCD) in elderly patients with fracture. However, no systematic review has addressed this issue. Thus, this systematic review investigated the effectiveness of dexmedetomidine on POCD in elderly patients with fracture.

METHODS

In this study, we searched electronic databases of PubMed, EMBASE, Cochrane Library, China National Knowledge Infrastructure, Wang Fang and China Science and Technology Journal Database from their initiation to July 1, 2022. We considered randomized controlled trials of dexmedetomidine on POCD in elderly patients with fracture in this study. Primary outcome was measured by mini-mental state examination. Secondary outcomes were measured by total occurrence rate of postoperative cognitive dysfunction, occurrence rate of delirium, visual analogue scale and occurrence rate of adverse events.

RESULTS

A total of 10 studies involving 969 elderly patients with fracture are included in this study. Meta-analysis results showed that there were significant differences on mini-mental state examination at 1-day post-surgery [mean difference (MD) = 2.17; random 95% confidence interval (CI), 1.06, 3.28; P < .001; I²=98%], 3-day post-surgery (MD = 2.70; random 95% CI, 1.51, 3.89; P < .001; I²=98%), and 7-day post-surgery (MD = 1.21; random 95% CI, 0.50, 1.93; P < .001; I²=86%), total occurrence rate of postoperative cognitive dysfunction (odds ratio [OR] = 0.26; fixed 95% CI, 0.11, 0.60; P = .002; I²= 0%), occurrence rate of delirium (OR = 0.29; fixed 95% CI, 0.11, 0.78; P = .01; I²= 0%), visual analogue scale (MD = -1.23; random 95% CI, -1.74, -0.72; P < .001; I²=95%), and occurrence rate of adverse events (OR = 0.32; fixed 95% CI, 0.20, 0.50; P < .001; I²= 0%) between the 2 groups.

CONCLUSION

The results of this study showed that dexmedetomidine could effectively manage POCD in elderly patients with fracture. However, the overall quality of included trials is not too high. Thus, the present findings should be cautiously referred.

Isoflurane impairs GluN2B-containing NMDA receptors trafficking and cognition via decreasing histone acetylation and EphB2 expression in aged hippocampal neurons

Perioperative neurocognitive disorders (PND) is a common complication that occurs among elderly patients in the perioperative course. Current clinical evidence has shown that isoflurane exposure could cause cognitive decline, but the exact molecular mechanisms remain unclear. As both NMDARs-dependent synaptic plasticity and histone acetylation play vital roles in processing learning and memory, we postulated that these alternations might occur in the isoflurane-associated PND. Here, we found that isoflurane impaired fear memory in aged mice, decreased GluN2B-containing NMDA receptors phosphorylation and trafficking, as well as the expression of EphB2, a key regulator of synaptic localization of NMDA receptors. We also identified that isoflurane could increase the expression of HDAC2, which was significantly enriched at the ephb2 gene promoter and regulated the transcription of ephb2. Furthermore, we showed that suberoylanilide hydroxamic acid (SAHA), a nonselective HDAC inhibitor or knocking-down HDAC2 rescued the cognitive dysfunction in isoflurane-treated aged mice via increasing acetylation of H3Ac, expression of EphB2 and promoting NMDA receptor trafficking. Collectively, our study highlighted the crucial role of histone posttranslational modifications for EphB2-GluN2B signals in isoflurane-associated PND, and modulating HDAC2 might be a new therapeutic strategy for isoflurane-associated PND.

Amelioratory Effect of Melatonin on Cognition Dysfunction Induced by Sevoflurane Anesthesia in Aged Mice

Background

Postoperative cognitive dysfunction (POCD) can be described as a clinical phenomenon characterized by cognitive impairment in patients, particularly elderly patients, after anesthesia and surgery. Researchers have focused on the probable effect of general anesthesia drugs on cognitive functioning status in older adults. Melatonin is an indole-type neuroendocrine hormone with broad biological activity and potent anti-inflammatory, anti-apoptotic, and neuroprotective effects. This study investigated the effects of melatonin on cognitive behavior in aged mice anesthetized with sevoflurane. In addition, melatonin's molecular mechanism was determined.

Objectives

This study aimed to investigate the mechanisms of melatonin against sevoflurane-induced neurotoxicity.

Methods

A total of 94 aged C57BL/6J mice were categorized into different groups, namely control (control + melatonin (10 mg/kg)), sevoflurane (sevoflurane + melatonin (10 mg/kg)), sevoflurane + melatonin (10 mg/kg) + phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) inhibitor LY294002 (30 mg/kg), and sevoflurane + melatonin (10 mg/kg) + mammalian target of rapamycin (mTOR) inhibitor (10 mg/kg). The open field and Morris water maze tests were utilized to assess the neuroprotective effects of melatonin on sevoflurane-induced cognitive impairment in aged mice. The expression levels of the apoptosis-linked proteins, PI3K/Akt/mTOR signaling pathway, and pro-inflammatory cytokines in the brain's hippocampus region were determined using the Western blotting technique. The apoptosis of the hippocampal neurons was observed using the hematoxylin and eosin staining technique.

Results

Neurological deficits in aged, sevoflurane-exposed mice were significantly decreased after melatonin treatment. Mechanistically, melatonin treatment restored sevoflurane-induced down-regulated PI3K/Akt/mTOR expression and significantly attenuated sevoflurane-induced apoptotic cells and neuroinflammation.

Conclusions

The findings of this study have highlighted the neuroprotective effect of melatonin on sevoflurane-induced cognitive impairment via regulating the PI3K/Akt/mTOR pathway, which might be effective in the clinical treatment of elderly patients with anesthesia-induced POCD.

Cognitive impairment induced by sevoflurane anesthesia is mediated by the cholinergic system after gastrointestinal surgery in older patients: A randomized, controlled trial

Delayed neurocognitive recovery after surgery is associated with increased morbidity and mortality. However, its mechanism of action remains controversial and complex. A prospective, double-blind, randomized controlled trial was performed at the Affiliated Hospital of Zunyi Medical University. Older patients (aged 65 years and older) who underwent gastrointestinal surgery were randomly divided into sevoflurane-based or propofol-based anesthesia groups. The Mini-Mental State Examination was performed to evaluate cognitive function. Peripheral venous blood was collected to test the levels of choline acetyltransferase and acetylcholinesterase. A total of 75 patients were enrolled and 30 patients in each group completed the study. On Day 1 postoperation, patients in the sevoflurane group showed worse performance on the Mini-Mental State Examination than patients in the propofol group. Lower blood choline acetyltransferase concentrations and higher acetylcholinesterase concentrations were observed in patients who had sevoflurane anesthesia than in patients who had propofol anesthesia 1 day postoperative. At 3 days postoperation, patients with sevoflurane- or propofol-based general anesthesia did not differ regardless of Mini-Mental State Examination score or choline acetyltransferase and acetylcholinesterase levels. Sevoflurane-based anesthesia has short-term delayed neurocognitive recovery in older surgical patients, which may be related to central cholinergic system degeneration.

Elevated serum alkaline phosphatase correlates with postoperative cognitive dysfunction: A retrospective cohort study based on STROBE statement

Little is known about the association between serum alkaline phosphatase (ALP) levels and postoperative cognitive dysfunction (POCD) after general anesthesia. Thus, we investigated the association of serum ALP levels with POCD in patients who underwent surgery with general anesthesia in a retrospective cohort study. We retrospectively collected data from patients who underwent surgery with general anesthesia between May 2016 and June 2020. Serum ALP activity was detected using a p-nitrophenyl phosphate assay. Pre-and postoperative cognitive function were evaluated using the Chinese version of the Mini-Mental State Examination. Univariate and multivariate logistic regression were used to explore the effect of ALP on cognitive function. The incidence of POCD was 13.5%. Compared with the control group, the POCD group had higher ALP levels. The neuropsychological test results suggested that the scores of most items were lower in the POCD group than in the non-POCD group. Univariate logistic regression indicated that increased ALP levels were significantly associated with cognitive dysfunction (odds ratio = 1.15, 95% confidence interval: 1.13-1.18, P = .000). Multivariate regression showed that elevated ALP was still associated with POCD after adjusting for confounding factors (odds ratio = 1.16, 95% confidence interval: 1.13-1.18, P = .000). The spline regression model indicated the dose-response associations between ALP level and POCD risk (P for nonlinear trend < .001). Our study indicated that elevated serum ALP was an independent predictive factor of POCD at the 3-month follow-up. The occurrence of POCD could be associated with inflammatory status.

Nomogram to predict postoperative cognitive dysfunction in elderly patients undergoing gastrointestinal tumor resection

OBJECTIVE

To establish a nomogram model for the prediction of postoperative cognitive dysfunction (POCD) in elderly patients undergoing gastrointestinal tumor resection.

METHODS

A total of 369 elderly patients scheduled for elective gastrointestinal tumor resection under general anesthesia were included. The cognitive function of each participant was assessed by the Mini-Mental State Examination (MMSE) 1 day before surgery and 7 days after surgery for the diagnosis of POCD. According to the results, patients were divided into a POCD group and a non-POCD group. The differences in hospitalization data and examination results between the two groups were compared. A logistic regression model was used to explore the risk factors for POCD in elderly patients undergoing gastrointestinal tumor resection, and a nomogram was then constructed based on these factors. The diagnostic performance of the nomogram was evaluated using the area under the receiver operating characteristic curve (AUROC) and a calibration plot. The clinical usefulness of the nomogram was estimated using decision curve analysis (DCA).

RESULTS

Among the 369 patients undergoing gastrointestinal tumor resection, 79 patients had POCD, with a positive rate of 21.4%. The nomogram model comprised the following variables: age, body mass index (BMI), history of cerebrovascular disease, preoperative white blood cell (WBC) count, preoperative hemoglobin (Hb) level, intra-operative blood loss, and operation time. The model showed good discrimination, with an area under the curve (AUC) of 0.710 (95% CI = 0.645-0.775), and good calibration (Hosmer-Lemeshow test, χ2 = 5.133, p = 0.274). Internal validation also maintained ideal discrimination and calibration. Decision curves indicated that when the threshold probability was above 0.1, the nomogram achieved more benefit than both the treat-all and treat-none policies.

CONCLUSION

This scoring system is the first nomogram model developed for the prediction of POCD in elderly patients undergoing gastrointestinal tumor resection. It has good efficacy in the prediction of POCD risk and could provide an important reference for the prevention, management, and treatment of POCD.

Young plasma reverses anesthesia and surgery-induced cognitive impairment in aged rats by modulating hippocampal synaptic plasticity

We investigated the protective effect of young plasma on anesthesia- and surgery-induced cognitive impairment and the potential underlying mechanism using bioinformatics, functional enrichment analysis, gene set enrichment analysis, Golgi-Cox staining, dendritic spine analysis, immunofluorescence assay, western blot analysis, and transmission electron microscopy. Furthermore, we performed behavioral assessments using the open field test, the novel object recognition test, and the Morris water maze test. We identified 1969 differentially expressed genes induced by young plasma treatment, including 800 upregulated genes and 1169 downregulated genes, highlighting several enriched biological processes (signal release from synapse, postsynaptic density and neuron to neuron synapse). Anesthesia- and surgery-induced cognitive impairment in aged rats was comparatively less severe following young plasma preinfusion. In addition, the decreased levels of synapse-related and tyrosine kinase B/extracellular signal-regulated protein kinase/cyclic adenosine monophosphate response element-binding protein (TrkB/ERK/CREB) signaling pathway-related proteins, dendritic and spine deficits, and ultrastructural changes were ameliorated in aged mice following young plasma preinfusion. Together, these findings suggest that young plasma reverses anesthesia- and surgery-induced cognitive impairment in aged rats and that the mechanism is associated with the activation of the TrkB/ERK/CREB signaling pathway and improvement in hippocampal synaptic plasticity.

Influence of dexmedetomidine on postoperative cognitive dysfunction in the elderly: A meta-analysis of randomized controlled trials

INTRODUCTION

Dexmedetomidine (Dex) is suggested to be neuroprotective. However, influence of Dex on postoperative cognitive dysfunction (POCD) in the elderly remains unknown.

METHODS

We performed a meta-analysis of randomized controlled trials (RCTs) to evaluate the effect of Dex on POCD. Relevant studies were obtained by search of PubMed, Embase, and Cochrane's Library databases. A random-effect model was used to pool the results.

RESULTS

Fourteen RCTs including 1626 adults of 60 years or older who received surgery with general anesthesia were included. Because methodologically diverse scales were used for POCD, eight RCTs with POCD diagnosed with Mini-Mental State Examination (MMSE) were included in the meta-analysis, while the remaining six RCTs with POCD diagnosed with other scales were qualitative synthesized. Pooled results of RCTs with MMSE showed that Dex significantly reduced the incidence of POCD (risk ratio: 0.47, 95% confidence interval: 0.37-0.60, p < 0.001) with no significant heterogeneity (I2  = 0%) or publication bias (p for Egger's regression test = 0.579). For the remaining six RCTs with POCD diagnosed with other scales, three of them showed that Dex was associated with a significantly lower incidence of POCD, while the other three RCTs did not show a significant difference.

CONCLUSIONS

Dex is associated with a reduced risk of POCD in elderly patients receiving surgeries with general anesthesia, and the results were mainly obtained in studies with POCD diagnosed with MMSE. Based on these findings, Dex may be considered as a preventative measure for POCD in elderly patients.

Effect of Different Vitamin D Levels on Cognitive Function in Aged Mice After Sevoflurane Anesthesia

Although the biological relationship between vitamin D (VD) deficiency and cognitive function has been recognized by many scholars, the theoretical mechanisms involved are still not well-understood. In this study, we demonstrated the role of VD in alleviating the cognitive dysfunction in aged mice caused by sevoflurane anesthesia. Forty female C57BL/6 mice aged 12 months were selected for the experiment. VD (-) and VD (+) mouse models and sevoflurane anesthesia models were established. Mice were randomly divided into normal elderly group (NC group), normal aged mice + sevoflurane anesthesia treatment group (NS group), aged VD (-) mice + sevoflurane anesthesia treatment group [VD (-) group], and aged VD (+) + sevoflurane anesthesia treatment group [VD (+) group]. To compare the emergence time after sevoflurane anesthesia in aged mice with different levels of VD and to test the cognitive function of four groups through the water maze. Inflammatory factor expression and cholinergic activity in hippocampus tissue of all mice were measured at the end of behavioral tests. These data show that, low levels of VD aggravated the delayed emergence and cognitive dysfunction in aged mice caused by sevoflurane anesthesia, while higher levels of VD mitigated this impairment by enhancing cholinergic activity and reducing inflammatory factor expression in the hippocampus.

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.

Electro-Acupuncture Pretreatment Ameliorates Anesthesia and Surgery-Induced Cognitive Dysfunction Via Inhibiting Mitochondrial Injury and nEuroapoptosis in Aged Rats

Postoperative cognitive dysfunction (POCD) remains one of the most common complications following anesthesia and surgery (AS) in the elderly population. Calcium-mediated mitochondrial injury has been proved to induce cognitive impairment in a variety of neurologic diseases. In the current study we determined whether electro-acupuncture (EA) pretreatment ameliorated AS-induced POCD in aged rats, as well as the underlying mechanism. Eighty SD rats (18 months, male) were randomly assigned into four groups (n = 20): C, C + EA, POCD and EA + POCD. Rats in Group POCD and EA + POCD were subjected to exploratory laparotomy under sevoflurane anesthesia. Rats of Group C + EA and EA + POCD received a 5-day EA stimulation at Hegu, Neiguan and Zusanli acupoints before AS. At 3rd day after AS, open field test along with Morris water maze test were employed to examine the cognitive function of aged rats. Then hippocampal tissues were stripped and hippocampal neuronal amount, expression level of cleaved caspase-9 level, cytochrome c (Cyt C), cleaved caspase-3 level, Bcl-2, Bax, ROS expression level, apoptosis rate, mitochondrial membrane potential (MMP), cytosolic calcium concentration ([Ca²⁺]c), opening level of mitochondrial permeability transition pore (mPTP) and ultrastructure of hippocampal neurons were detected separately. EA pretreatment inhibited AS-induced cognitive dysfunction. Furthermore, EA pretreatment decreased level of [Ca²⁺]c, MMP, mPTP, ROS and hippocampal mitochondrial disruption and enhanced neuronal amount. In addition, EA pretreatment notably reduced the AS-induced increased level of cleaved caspase-9, cleaved caspase-3 and expression of Cyt c, Bax/Bcl-2 ratio, as well as neuronal apoptosis rate in aged rats. EA pretreatment ameliorates AS-induced POCD in aged rats, the potential mechanism may be associated with inhibiting calcium overload and ameliorating mitochondrial injury and neuroapoptosis in hippocampal neurons.

Transcutaneous Electrical Acupoint Stimulation Improving Postoperative Cognitive Function in Senior Patients Undergoing Video-Assisted Thoracoscopic Surgery: A Randomized Controlled Trial

OBJECTIVE

To evaluate the effectiveness and safety of transcutaneous electrical acupoint stimulation (TEAS) for improving postoperative cognitive function in senior patients undergoing video-assisted thoracoscopic surgical (VATS).

METHODS

From January to December 2020, 97 participants were randomly assigned to the TEAS group (49 cases) and the control group (48 cases) by a random number table. The patients in the TEAS group received TEAS, at the bilateral Neiguan (PC 6) and Zusanli (ST 36) acupoints. The control group received sham TEAS. The stimulation was started from 30 min before surgery until the end of the operation. The primary outcome was the incidence of pstoperative cognitive dysfunction (POCD), diagnosed based on the changes in the Mini-Mental Status Examination (MMSE) and Montreal Cognitive Assessment (MoCA) scores. The secondary outcomes were plasma levels of S100β protein and neuron-specific enolase (NSE).

RESULTS

The incidence of POCD on day 1 and 3 after surgery in the TEAS group was significantly lower than that in the control group [day 1 after surgery: 28.3% (13/46) vs. 52.3% (23/44), P=0.028; day 3 after surgery: 21.7% (10/46) vs. 40.9% (18/44), P=0.043]. Compared with baseline, the MMSE and MoCA scores decreased to various extents in both groups. The MMSE scores on day 1, 3, and 5 after surgery and MoCA scores on day 1, 3, 5, and 7 after surgery in the TEAS group were higher than those in the control group (all P<0.05) in both groups. Compared with baseline, the plasma levels of S100β and NSE were significantly increased at 4, 8, 12, 24 h after surgery (all P<0.05). Compared with the control group, the plasma levels of S100β and NSE were lower in the TEAS group at 4, 8, 12, and 24 h after surgery (all P<0.05). No obvious adverse events were found during the trial.

CONCLUSION

Application of TEAS in senior patients after VATS could reduce incidence of POCD and improve postoperative cognitive function.

Characterization of circRNA-Associated-ceRNA Networks Involved in the Pathogenesis of Postoperative Cognitive Dysfunction in Aging Mice

Postoperative cognitive dysfunction (POCD) is a clinical entity associated with declined cognitive function following surgery. It occurs more frequently in elderly patients. Recent studies have shown that circRNA-associated-ceRNA networks, constructed based on interactions between circRNA-miRNA and miRNA-mRNA, provide key insight into the molecular mechanisms underlying the pathogenesis of several neurological diseases. However, the mechanism of POCD remains undetermined. In this study, laparotomies were performed under isoflurane anesthesia on young (2-month-old) and aging (17-month-old) male C57BL/6 mice. The results showed that the aging mice were more likely than the young mice to develop POCD. Subsequently, differentially expressed circRNAs, miRNAs, and mRNAs were characterized by RNA sequencing the hippocampi of young and aging mice under control and surgery conditions. Six circRNAs, 6 miRNAs, and 203 mRNAs were identified to construct the circRNA-associated-ceRNA network for the control condition, while 13 circRNAs, 8 miRNAs, and 189 mRNAs were used for the circRNA-associated-ceRNA network for the surgery condition. Further Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis of these two networks revealed that the circRNA-associated-ceRNA networks are involved in POCD pathogenesis though modulating the Wnt and VEGF signaling pathways, as well as neural processes associated with long-term synaptic depression and synaptic transmission. In particular, the mmu-miR-298-5P regulatory pathway identified in this study’s mouse model suggests that mm9_circ_009789- and mm9_circ_004229-associated-ceRNA networks as closely related to the occurrence of POCD through regulating PKC signaling pathway, neural cell apoptosis and glycolipid metabolism pathway. These findings provide possible insight into the role of the circRNA-associated-ceRNA networks, helping to unravel the complexity of the molecular pathogenesis of POCD.

Postoperative rehabilitation of neurosurgical patients after spinal cord surgery – results of our own study

Aim. To assess the extent to which cognitive and emotional disorders in patients undergoing spinal cord surgery affect the quality of rehabilitation and, based on the data obtained, to suggest optimization of rehabilitation measures. Materials and methods. The study included 60 patients (30 men and 30 women) whose condition required spinal cord surgery. All patients underwent assessment of somatic and neurological status, as well as quantitative neuropsychological testing. The influence of cognitive and emotional disorders before and after surgery on the severity of pain syndrome and movement disorders was assessed. When included in the study, patients were randomized into the main (30 people) and control (30 people) group. The patients of the main group received cognitive-motor training, which was carried out using the methodological manual Cognitive Training for Patients with Moderate Cognitive Impairment, developed by the staff of the Department of Nervous Diseases and Neurosurgery of the Sechenov First Moscow State Medical University (Sechenov University). Cognitive, emotional, motor disorders, severity of pain syndrome, as well as the quality of life and adherence of patients to cognitive-motor training were assessed 3 and 6 months after the surgical intervention.The severity of cognitive and emotional disorders in patients of the main and control groups did not differ before the operation. Results. After the operation, the severity of cognitive impairments was significantly higher in patients of the control group (p=0.03). Patients in the control group were significantly worse than patients in the main group in performing memory tasks (p=0.00), they also had a significantly lower rate of mental processes (p=0.00). These differences persisted 3 months after surgery (p=0.00). A week after the surgical intervention, the severity of anxiety and depression was significantly higher in patients in the control group (p=0.01). The positive effect of the operation in the form of pain reduction was achieved in all patients, but in the control group there was an increase in the severity of the pain syndrome after six months of observation compared with that after three months. An increase in the severity of the pain syndrome was associated with an increase in depression, anxiety, and cognitive impairment. The analysis showed that patients of the main group with high adherence to cognitive training showed significantly greater positive dynamics both in terms of cognitive functions and in terms of anxiety and depression (p0.05). A survey of patients after inclusion in the study with the provision of prospective recommendations for clinical care showed the following: 58 patients (96.7% of patients) noted that the proposed recommendations for clinical care, from their point of view, would significantly improve their postoperative prognosis. Important points that should be reflected in the clinical guidelines for the management of patients with spinal cord surgery, from the point of view of patients, were: discussion with the doctor of the picture of their illness, duration of hospitalization, expected outcome, prognosis (60 patients, 100%), medical education rehabilitation skills (51 patients, 85% of patients), communicating with patients who have already undergone a similar operation earlier in this surgical department (49 patients, 81.7%), ensuring continuity and discussing the entire rehabilitation route before surgery (60 patients, 100%). Conclusion. Cognitive and emotionally disorders determine the quality of life and rehabilitation of patients who have undergone surgery on the spinal cord. Our results allow us to recommend the inclusion of cognitive-motor training in the rehabilitation program for patients after spinal neurosurgical operations.

Cognitive impairment in candidates for allogeneic hematopoietic stem cell transplantation

Hematopoietic cell transplant (HCT) is an increasingly common and curative treatment strategy to improve survival among individuals with malignant and nonmalignant diseases, with over one million HCTs having been performed worldwide. Neurocognitive dysfunction is a common and untoward consequence of HCT for many recipients, although few studies have examined the profile of neurocognitive impairments in HCT or their association with clinical features, such as frailty, or the incidence of pre-HCT neurocognitive impairments across all ages, which may influence post-HCT neurocognitive impairments. We examined the pattern and correlates of pre-transplant neurocognitive dysfunction in a prospective sample of adults undergoing HCT. Neurocognition was assessed using the Montreal Cognitive Assessment Battery. Frailty was assessed using the Short Physical Performance Battery. Linear regression analysis was used to examine the associations between neurocognitive performance and frailty. Neurocognitive screening profiles were also examined by partitioning MoCA into domain scores, including Executive Function and Memory. We also examined the associations between neurocognition, frailty, and clinical outcomes, including length of transplant hospitalization and survival. One hundred and ten adults were evaluated across a wide age range (range: 19-75; mean age = 54.7 [SD = 14.1]). Neurocognitive performance tended to fall below published normative levels (mean MoCA = 25.5 [SD = 4.1]), with 17% of participants demonstrating impaired performance compared with medical normative data (MoCA ≤ 22) and 34% exhibiting impaired performance relative to healthy samples (MoCA ≤ 25). Mild impairments (MoCA ≤ 25) were common across age ranges, including middle-aged patients (23% for age < 50; 35% for age 50-60, 41% for age ≥ 60), particularly for items assessing Executive Function. Greater levels of frailty associated with lower neurocognitive screening scores (r = -0.29, P < 0.01) and Executive Functioning (r = -0.24, P < 0.01), whereas greater age was associated with poorer Memory performance only (r = -0.33, P < 0.01). Greater levels of frailty prior to transplant associated with longer length of stay (β = 0.10, P = 0.046), but were not associated with survival. Neurocognitive impairments are common among adults undergoing HCT and the pattern of performance varies by age. Pre-transplant frailty is associated with neurocognitive functioning and may portend worse post-transplant early clinical outcomes.

Electroacupuncture ameliorates postoperative cognitive dysfunction and associated neuroinflammation via NLRP3 signal inhibition in aged mice

Background

Postoperative cognitive dysfunction (POCD) is associated with worsened prognosis especially in aged population. Clinical and animal studies suggested that electroacupuncture (EA) could improve POCD. However, the underlying mechanisms especially EA’s regulatory role of inflammasomes remain unclear.

Methods

The model of POCD was established by partial hepatectomy surgery in 18‐month mice with or without postoperative EA treatment to the Baihui acupoint (GV20) for 7 days. Cognitive functions were assessed by Morris water maze test, and proinflammatory cytokines IL‐1β and IL‐6 and microglia activity were assayed by qPCR, ELISA, or immunohistochemistry. Tight junction proteins, NLRP3 inflammasome and downstream proteins, and NF‐κB pathway proteins were evaluated by western blotting.

Results

EA markedly preserved cognitive dysfunctions in POCD mice, associated with the inhibition of neuroinflammation as evidenced by reduced microglial activation and decreased IL‐1β and IL‐6 levels in brain tissue. EA also preserved hippocampal neurons and tight junction proteins ZO‐1 and claudin 5. Mechanistically, the activation of NLRP3 inflammasome and NF‐κB was inhibited by EA, while NLRP3 activation abolished EA’s treatment effects on cognitive function.

Conclusion

EA alleviates POCD‐mediated cognitive dysfunction associated with ameliorated neuroinflammation. Mechanistically, EA’s treatment effects are dependent on NLRP3 inhibition.

The Association between Postoperative Cognitive Dysfunction and Cerebral Oximetry during Geriatric Orthopedic Surgery: A Randomized Controlled Study

Background

Postoperative cognitive dysfunction (POCD) refers to disorders affecting orientation, attention, perception, consciousness, and judgment that develop after geriatric orthopedic surgery. Cerebral blood oxygen saturation detection is a way to diagnose cerebral oxygen supply during operation. At present, more and more applications are used for early diagnosis of postoperative cognitive function. Therefore, the present study is to analyze the relationship between postoperative cognitive dysfunction and cerebral blood oxygen saturation in elderly orthopedic patients.

Methods

This study enrolled 90 elderly patients undergoing orthopedic surgery in our hospital. According to the postoperative cognitive dysfunction, they were divided into POCD group (N = 45) and no-POCD (N = 45) group. The cognitive and psychological function and cerebral blood oxygen saturation were analyzed before and 3 months after the operation. Finally, the indicators of cognitive psychological function and the indicators of cerebral blood oxygen saturation are correlated and analyzed.

Results

Compared with the normal group, patients with cognitive dysfunction at 3 months after surgery time below preoperative rScO2, time below a 10% decrease from preoperative rScO2, CDL preoperative, minimum rScO2 value, and maximum rScO2 value have significant changes. The results of the correlation analysis found that there is also a significant correlation between the postoperative cognitive and psychological function of the patient and the cerebral blood oxygen saturation at 3 weeks after the operation.

Conclusion

In elderly orthopedic patients, there is a significant relationship between cerebral blood oxygen saturation detection and cognitive function 3 months after surgery.

The effect of dexmedetomidine combined with epidural anesthesia on post-operative cognitive dysfunction in elderly patients after orthopedic surgery

OBJECTIVE

To investigate the effect of dexmedetomidine combined with epidural anesthesia on cognitive dysfunction (POCD) in elderly patients after orthopedic surgery.

METHODS

A total of 187 elderly patients who needed orthopedic surgery in our hospital from January 2019 to December 2020 were randomly divided into an experimental group (n=95) and a control group (n=92). The patients in the experimental group were administered 1 μg/kg dexmedetomidine hydrochloride injections, and the patients in the control group were administered 0.9% sodium chloride injections, which were infused using a micropump for about 10 minutes. The two groups' cognitive function, VAS scores, and vital signs were compared.

RESULTS

There were significant differences in the two groups' mean arterial pressures and heart rates at intubation time (T3), operation start time (T4), and extubation time (T6) (P < 0.05). The VAS scores in the experimental group were significantly different from the VAS scores in the control group at 24 hours after the operations, 48 hours after the operations, 72 hours after the operations, and 7 days after the operations (P < 0.05). There were no significant differences in the anesthesia times, the average bleeding volumes, or the average operative durations (P > 0.05). 48 hours after the operations, the MMSE score in the experimental group was (27.15±1.17), which was significantly different than the MMSE score in the control group (23.11±0.83), and the difference was statistically significant (P < 0.05).

CONCLUSION

Epidural anesthesia combined with dexmedetomidine has little circulatory interference in elderly patients; moreover, it can reduce the incidence of postoperative cognitive dysfunction in elderly patients.

A new mechanism of POCD caused by sevoflurane in mice: cognitive impairment induced by cross-dysfunction of iron and glucose metabolism

Sevoflurane (Sev) is a commonly used anesthetic in hospitals that can cause neurotoxicity. Postoperative cognitive dysfunction (POCD) is a common clinical problem induced by some anesthetics. However, the exact mechanism of neurotoxicity induced by Sev is unclear. Here we studied a new mechanism of POCD induced by Sev. We treated 15-month-old mice with 2% Sev for 6 hours, and we had found that Sev causes POCD. Using isobaric tags for relative and absolute quantitation (iTRAQ), we found that the transporter and the metabolism of carbohydrates and inorganic ions were involved in the cognitive impairment induced by Sev. Using synchrotron radiation micro-X-ray fluorescence (μ-XRF), we showed that Sev caused the iron overload in the brain of 15-month-old mice. Subsequently, excessive iron led to oxidative stress and impaired mitochondrial function that further led to glucose metabolism disorder and reduced ATP production by regulating the expression of key enzyme genes or proteins including G6Pase, Pck1, and Cs. Meanwhile, Sev also inhibited the oxygen consumption rate and glucose absorption by downregulating the expression of glucose transporter 1 in cerebral vascular endothelial cells. The cross-dysfunction of iron and glucose metabolism caused the apoptosis in the cortex and hippocampus through Bcl2/Bax pathway. In conclusion, the data here showed a new mechanism that Sev caused apoptosis by cross-dysregulation of iron and glucose metabolism and induced energy stress in mice. Maintaining iron and glucose metabolism homeostasis may play an important role in cognitive impairment induced by Sev.

Clemastine Ameliorates Perioperative Neurocognitive Disorder in Aged Mice Caused by Anesthesia and Surgery

Perioperative neurocognitive disorder (PND) leads to progressive deterioration of cognitive function, especially in aged patients. Demyelination is closely associated with cognitive dysfunction. However, the relationship between PND and demyelination remains unclear. Here we showed that demyelination was related to the pathogenesis of PND. Clemastine, an antihistamine with potency in remyelination, was predicted to have a potential therapeutic effect on PND by next-generation sequencing and bioinformatics in our previous study. In the present study, it was given at 10 mg/kg per day for 2 weeks to evaluate the effects on PND in aged mice. We found that clemastine ameliorated PND and reduced the expression levels of inflammatory factors such as tumor necrosis factor alpha (TNF-α) and interleukin-1 beta (IL-1β). Further investigation suggested clemastine increased the expression of oligodendrocyte transcription factor 2 (OLIG2) and myelin basic protein (MBP) to enhance remyelination by inhibiting the overactivation of the WNT/β-catenin pathway. At the same time, the expression of post-synaptic density protein 95 (PSD95, or DLG4), brain-derived neurotrophic factor (BDNF), synaptosomal-associated protein 25 (SNAP25) and neuronal nuclei (NEUN) were also improved. Our results suggested that clemastine might be a therapy for PND caused by anesthetic and surgical factors in aged patients.

Pleiotrophin Potentiates Sevoflurane Anesthesia-induced Learning Deficits in Mice

Postoperative cognitive dysfunction (POCD) is a major postoperative neurological complication in children and the elderly. However, the detailed mechanisms underlying this process remain unclear. This study aims to investigate the effect of pleiotrophin on sevoflurane-induced neuroinflammation and cognitive impairment. The novel object recognition test was performed to evaluate the cognitive and motor function of aged C57BL/6 (wild-type, WT) and pleiotrophin-knockout mice treated with sevoflurane. Small molecule inhibitors targeting receptor protein tyrosine phosphatase (RPTP) β/ζ, a pleiotrophin receptor, were used to ameliorate cognitive dysfunction. Sevoflurane treatment induced cognitive dysfunction and motor impairment in aged WT mice. Sevoflurane anesthesia induced the upregulation of certain inflammatory cytokines. Pleiotrophin knockout ameliorated the sevoflurane-induced cognitive dysfunction and motor impairment in vivo. Treatment with small molecule inhibitors targeting RPTP β/ζ inhibited sevoflurane-induced neuroinflammation. In summary, pleiotrophin was shown to potentiate sevoflurane anesthesia-induced cognitive dysfunction and learning deficits in mice.

Identification of the Potential Gene Regulatory Networks and Therapeutics in Aged Mice With Postoperative Neurocognitive Disorder

Postoperative neurocognitive disorder (PND) is one of the most common postoperative neurological complications in aged patients, characterized by mental disorder, anxiety, personality changes, and impaired memory. At present, the molecular mechanism of PND remains largely unclear, and the ideal biomarker for clinical diagnosis and prognosis are lacking. Circular RNA (circRNA) and microRNA (miRNA), as unique non-coding RNAs, affecting the regulation of miRNAs on genes and further intervening in the progression of diseases through the sponge action between the two. Besides, it could be served as novel biomarkers in various diseases. In order to detect the differential expression profiles of genes caused by PND, a total of 26 18-month-old male C57BL/6 mice were randomly assigned to control group and PND group. Behavioral tests showed that mice in the PND group had impaired cognitive function compared with the control group. Three mice in each group were randomly selected to harvest the brain for analysis the expressions of circRNAs, miRNAs, and mRNAs in the prefrontal cortex by next-generation sequencing (NGS) technology. Differentially expressed genes, including 1192 circRNAs, 27 miRNAs, and 266 mRNAs were identified, and its accuracy was further confirmed by qRT-PCR. Bioinformatics analysis results suggested that neuroinflammation was the main pathological mechanism of PND. The construction of competitive endogenous RNA (ceRNA) networks and the identification of hub genes provided possible therapeutic targets for PND. Cinnarizine and Clemastine were predicted to have the potential therapeutic effects on PND. This is the first study to explore the differential expression profiles of genes and their regulation mechanisms in PND, our results provided new clues and targets for the treatment of this refractory disease.

Does propofol ameliorate occurrence of postoperative cognitive dysfunction after general anaesthesia? A protocol of systematic review

BACKGROUND

Postoperative cognitive dysfunction (POCD) is a common condition after general anesthesia (GA). Previous studies have reported that propofol can ameliorate the occurrence of such disorder. However, its results are still inconsistent. Therefore, this systematic review will assess the efficacy and safety of propofol on POCD after GA.

METHODS

Literature sources will be sought from inception to the present in Cochrane Library, MEDLINE, EMBASE, PsycINFO, Web of Science, Scopus, Allied and Complementary Medicine Database, Chinese Biomedical Literature Database, and China National Knowledge Infrastructure for randomized controlled trials (RCTs) assessing the administration of propofol on POCD after GA. All searches will be carried out without limitations to language and publication status. Outcomes comprise of cognitive impairments changes, impairments in short-term memory, concentration, language comprehension, social integration, quality of life, and adverse events. Cochrane risk of bias tool will be utilized to assess study quality. We will evaluate the quality of evidence for each outcome using Grading of Recommendations Assessment, Development and Evaluation approach. A narrative synthesis or a meta-analysis will be undertaken as appropriate.

DISCUSSION

This study will systematically and comprehensively search literature and integrate evidence on the efficacy and safety of propofol on POCD after GA. Our findings will be of interest to clinicians and health-related policy makers.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42020164096.

Electroacupuncture Pretreatment Ameliorates Anesthesia and Surgery-Induced Cognitive Dysfunction via Activation of an α7-nAChR Signal in Aged Rats

OBJECTIVE

Postoperative cognitive dysfunction (POCD) after anesthesia and surgery (AS) is a common complication in the elderly population. A cholinergic-dependent signal, the alpha7-nicotinic acetylcholine receptor (α7-nAChR), has been suggested to regulate cognitive processes in a variety of neurologic diseases. In the current study, we determined whether electroacupuncture (EA) pretreatment ameliorates AS-induced POCD in aged rats, as well as the underlying mechanism.

METHODS

Male Sprague-Dawley rats (20 months old) were randomly assigned to the following 5 groups (n=12): vehicle; POCD (tibial fracture surgery); EA plus POCD; EA plus POCD and alpha-bungarotoxin (α-BGT); and POCD plus α-BGT groups. Alpha-bungarotoxin (1 μg/kg), a selective antagonist of α7-nAChR, was administrated via intraperitoneal injection before EA. Thirty days post-AS, the Morris water maze and a novel objective recognition test were used to evaluate cognitive function. Neuronal amount, apoptosis, microglial activation, percentage of high mobility group box 1 (HMGB1)- and nuclear factor-κB (NF-κB)-positive microglia, and levels of HMGB-1 downstream factors, including NF-κB, interleukin-6 (IL-6), and IL-1β, were detected by Nissl staining, immunofluorescence, and Western blot assays.

RESULTS

EA pretreatment significantly increased crossing platform times and elevated the time with a novel object, restored the quantity of neurons, decreased TUNEL-positive neurons, alleviated activation of microglia, downregulated expression of HMGB1 and NF-κB in the microglia, and reduced levels of phosphor-NF-κB, IL-6, and IL-1β 35 days after AS, while α-BGT partially reversed these changes.

CONCLUSION

EA pretreatment improved AS-induced POCD in aged rats, and the underlying mechanism may be associated with inhibition of HMGB1-NF-κB via an α7-nAChR signal in the microglia.

[Postoperative cognitive disorder]

Cognitive impairment or delirium occurs in about 40% of elderly patients after surgery. The increasing number of elderly people has led to a significant increase in the number of cases of postoperative cognitive dysfunction (POCD). This is one of the most important medical and social problems, the analysis of which is especially difficult, since it requires the coordination of a large number of specialties: anesthesiology, surgery, neurology, psychiatry, neuropsychology, as well as fundamental neurosciences. Thus, a systematic multidisciplinary approach that takes into account all possible factors affecting the condition of patients should be considered. The article is devoted to the main aspects of the pathogenesis, prevention and treatment of POCD.

Pharmacological Agents That Prevent Postoperative Cognitive Dysfunction in Patients With General Anesthesia: A Network Meta-analysis

BACKGROUND

Postoperative cognitive dysfunction (POCD) is associated with prolonged hospital stays, increased mortality, and negative socioeconomic consequences. Dexmedetomidine, ketamine, dexamethasone, and lidocaine have previously been reported to be effective for preventing POCD.

STUDY QUESTION

In this network meta-analysis, we apply direct and indirect comparisons to rank these pharmacological agents in terms of their effect on POCD, through which we seek to provide evidence for future clinical medication.

DATA SOURCES

A comprehensive literature search of PubMed, EMBASE, the Cochrane Library, and Web of Science was conducted to identify randomized controlled trials that examined the effects of dexmedetomidine, ketamine, dexamethasone, or lidocaine on POCD induced by general anesthesia.

STUDY DESIGN

For eligible studies, 2 reviewers independently extracted data and assessed the respective risk of bias. Bayesian network meta-analysis was conducted using R-3.4.1 software. A total of 30 articles were included in this meta-analysis.

RESULTS

Direct comparison showed that dexmedetomidine [odds ratio (OR) = 0.42, 95% confidence interval (CI): 0.32-0.55] may decrease the incidence of POCD for noncardiac surgery; dexmedetomidine (OR = 0.08, 95% CI: 0.01-0.63) and ketamine (OR = 0.09, 95% CI: 0.02-0.32) were found to decrease POCD for cardiac surgery. The R-software ranking result for prevention of POCD was dexmedetomidine, lidocaine, ketamine, placebo, and dexamethasone, respectively, in noncardiac surgery, and dexmedetomidine, ketamine, lidocaine, placebo, and dexamethasone in cardiac surgery.

CONCLUSION

Dexmedetomidine exhibited obvious superiority to other agents for noncardiac surgery; dexmedetomidine and ketamine exhibited a significantly better performance than other agents for cardiac surgery. Dexamethasone did not show better efficacy than the placebo. However, more rigorously designed studies comprising larger sample sizes are needed to confirm our findings.

Preoperative Chronic and Acute Pain Affects Postoperative Cognitive Function Mediated by Neurotransmitters

The effective prevention of postoperative cognitive dysfunction (POCD) needs to be explored, and the effect of preoperative pain on POCD remains unclear. We established a chronic pain model induced by chronic constriction injury (CCI) and models of acute pain and anxiety without pain in mice that were subsequently subjected to partial hepatectomy surgery. Morris water maze (MWM) tests were performed to evaluate the learning and memory abilities of the mice. ELISA was used to measure IL-1β, IL-6, and TNF-α in serum, and HPLC-MS was used to detect neurotransmitters in the prefrontal cortices and hippocampi of the mice. The results indicated that chronic pain induced by CCI might have significantly impaired the learning and memory abilities of mice, while acute pain and anxiety without pain only affected the memory abilities of mice. Perioperative acute pain increased the level of IL-1β in serum, and CCI might have increased the level of IL-6. CCI and acute pain increased dopamine (DA) levels in the cortex, similar to anxiety. Like anxiety, CCI increased 5-hydroxytryptamine (5-HT) levels in the prefrontal cortex and hippocampus. Acute pain led to a decrease in the acetylcholine (ACH) level in the hippocampus. Our results suggest that acute pain and CCI-induced chronic pain might aggravate postoperative cognitive dysfunction via neurotransmitters and by changing the levels of inflammatory factors such as IL-1β and IL-6.

Relationship between Urinary Alzheimer-Associated Neuronal Thread Protein and Apolipoprotein Epsilon 4 Allele in the Cognitively Normal Population

We investigated the relationship between urinary Alzheimer-associated neuronal thread protein (AD7c-NTP) levels and apolipoprotein epsilon 4 (ApoE ɛ4) alleles, as well as other factors that cause cognitive decline, in the cognitively normal population. We recruited 329 cognitively normal right-handed Han Chinese subjects who completed ApoE gene testing and urinary AD7c-NTP testing. There was no significant difference in urinary AD7c-NTP levels between the normal control and subjective cognitive decline groups. Urinary AD7c-NTP levels were significantly higher in subjects with ApoE ɛ3/4 and 4/4 [0.6074 (0.6541) ng/mL] than in subjects without ApoE ɛ4 [0.4368 (0.3392) ng/mL and 0.5287 (0.3656) ng/mL], and urinary AD7c-NTP levels positively correlated with ApoE genotype grade (r = 0.165, p = 0.003). There were significant differences in urinary AD7c-NTP levels between subjects with and without a history of coronary heart disease or diabetes. Urinary AD7c-NTP levels were not related to years of education, nature of work, family history of dementia, a history of hypertension, stroke, anemia, or thyroid dysfunction. Urinary AD7c-NTP levels were positively correlated with ApoE grade in the cognitively normal population. The relationship between risk factors of cognitive decline and urinary AD7c-NTP levels provides a new way for us to understand AD and urinary AD7c-NTP.