Surgery, neuroinflammation and cognitive impairment

Association of Cognitive Impairment and Peripheral Inflammation in Methamphetamine-dependent Patients: A Cross-sectional Study on Neuroinflammatory Markers TNF-α and IL-6

Objective

To investigate the cognitive impairment and peripheral inflammation induced by methamphetamine (METH) and their association in METH abusers.

Methods

The cross-sectional study included 100 METH-dependent patients and 100 healthy controls. Cognitive screening was conducted using the Thai version of the Montreal Cognitive Assessment (MoCA-T). Thirty normal controls and 30 METH-dependent patients were randomly selected for blood collection to measure inflammatory markers, including tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-6, using a quantitative enzyme-linked immunosorbent assay method.

Results

METH-dependent patients had significantly poorer MoCA-T scores and higher levels of blood inflammatory markers compared to healthy controls. Demographic characteristics, METH use patterns, and proinflammatory cytokines were associated with cognitive impairment. The MoCA-T score was negatively associated with plasma TNF-α and IL-6 levels.

Conclusion

METH-associated cognitive decline is correlated with elevated plasma levels of TNF-α and IL-6 cytokines, indicating the involvement of specific neuroinflammatory pathways in neurocognitive dysfunction. These insights could pave the way for novel therapeutic strategies aimed at mitigating neuroinflammation, potentially improving outcomes for individuals with METH addiction.

Lipid dysregulation and delirium in older adults: A review of the current evidence and future directions

Delirium is a complex medical condition marked by acute episodes of cognitive dysfunction and behavioral disturbances, with a multifaceted etiology and challenging management across various clinical settings. Older adults, particularly in postoperative contexts, are at increased risk of developing delirium. Despite extensive research, a single underlying pathophysiological mechanism for delirium remains elusive. However, emerging evidence suggests a correlation between lipid dysregulation and delirium development in elderly patients, especially in postoperative settings. This connection has led to proposed treatments targeting dyslipidemia and associated neuroinflammatory effects in acute-phase delirium. This review aims to synthesize current literature on the relationship between lipid dysregulation and delirium in older adults, highlighting the need for further research into specific neurolipidome constituents and age-related lipid profile changes, potentially uncovering novel therapeutic strategies for delirium.

Anaesthesia as a risk factor for long-term cognitive decline: Results of the prospective MAAS cohort study

BACKGROUND

There are concerns whether (repeated) exposure to general anaesthesia is associated with long-term cognitive decline.

OBJECTIVE

We investigated the potential, negative relationship between total exposure to surgery under general anaesthesia and its impact on long-term cognitive development.

DESIGN

A prospective longitudinal cohort study.

SETTING

The Netherlands.

PARTICIPANTS

1823 Adults, aged 25-84 with normal cognitive functioning on inclusion with three serial cognitive assessments between 1995 and 2008, with comprehensive documentation on demographic, lifestyle, and health factors.

MAIN OUTCOME MEASURES

The primary outcomes were test scores in the cognitive domains of learning and memory, executive function, selective attention, mental speed, and information processing speed. Linear mixed models were used to analyse the effects of the estimated total time under general anaesthesia at baseline on cognitive development during a 12-year follow-up period.

RESULTS

When adjusting for demographic and systemic health-related factors, prolonged exposure to surgery under general anaesthesia (measured in total baseline minutes) negatively affected three cognitive domains. These included the CST (executive functioning, P  < 0.05), Stroop (selective attention and mental speed, P  < 0.001) and LDST (information processing speed, P  < 0.005). Age and education were the primary factors impacting lifetime cognitive decline. Hypertension, diabetes, and smoking negatively affected various cognitive domains.

CONCLUSION

Increased exposure to surgery under general anaesthesia independently contributes to long-term cognitive decline. Demographic variables and health-related factors are key contributors to accelerated cognitive decline over an individual's lifetime.

Investigating the relationship between toll-like receptor activity, low-grade inflammation and cognitive deficits in schizophrenia patients - A mediation analysis

BACKGROUND

Schizophrenia is a debilitating psychiatric illness. Many studies report alterations in immune biomarkers (cytokines) in such patients. In addition, such prolonged low-grade inflammatory responses are associated with lowered cognitive performance. In this study, we investigated whether the expression and activity of Toll-like receptors (TLRs), receptors involved in initiating innate immune responses, are associated with the reported immune changes and, if so, whether they are associated with cognitive deficits in such patients.

METHODS

300 participants (202 healthy controls (HC) and 98 patients with schizophrenia (SZ)) were recruited. A battery of cognitive tasks using WAIS-III and CANTAB were administered to the participants. Whole blood collected from participants was used to assess TLR2, 3, and 4 activity. mRNA expression of cytokines and TLR1-10 were quantified using RT-QPCR. Using ELISA, plasma was analysed for basal levels of cytokines such as IL-6, IL-8, IL-10, IL-12, TNF-α, IFN-γ and C-reactive proteins (CRP).

RESULTS

We found significantly elevated plasma levels of IL-6, IL-8, IL-10, TNF-α, and CRP in the SZ group. In the SZ patient-only group, significantly higher levels of TLR2 and -4 activity (as measured by IL-6, IL-8, and IL-10 release following agonist stimulation) were observed. Significant negative associations in patients were observed between plasma IL-6 levels and measures of attention & processing speed and working memory; IL-8 and intelligence quotient; TNF-α and logical memory; and social cognition and IL-10 and CRP. Multiple-linear regression analysis suggests that TLR2 and TLR4 activity was associated with increased and decreased cytokine levels respectively and decreased cognitive performance. Finally, the significant association between TLR activity and decreased cognitive performance was mediated by IL-6 and IL-8.

CONCLUSION

We have demonstrated that patients with schizophrenia have elevated protein and mRNA expression of a range of cytokines and Toll-like receptors. Some of these changes are associated with deficits in cognition. Finally, our study has demonstrated a modest relationship between TLR activity and cognitive deficits in schizophrenia patients in a manner that may be mediated by IL-6 and IL-8.

Resveratrol-mediated NRF2/HO-1 signaling pathway to improve postoperative cognitive dysfunction in elderly rats

To investigate the effects of resveratrol (RES) on cognitive function and its modulation of the NRF2/HO-1 signaling pathway in a rodent model of postoperative cognitive dysfunction (POCD). A POCD model was established in aged Sprague-Dawley rats using sevoflurane anesthesia and laparotomy. Rats were divided into four groups: control, POCD, RES, and POCD + RES. Cognitive performance was assessed using the Morris water maze. Hippocampal tissues were analyzed for neuronal condition using hematoxylin and eosin and Nissl staining. The expression levels of inflammatory cytokines and oxidative stress markers were quantified by enzyme-linked immunosorbent assay. The messenger RNA and protein levels of NRF2, KEAP1, HO-1, and SOD2 were measured using real-time quantitative polymerase chain reaction and western blotting. RES treatment improved cognitive function, as evidenced by reduced escape latency and increased platform crossings in the Morris water maze. Histopathological analysis showed restoration of hippocampal structure and increased neuronal viability. RES significantly reduced proinflammatory cytokines interleukin (IL)-1 and IL-6 while increasing IL-10 levels. In addition, RES activated the NRF2/HO-1 pathway by upregulating NRF2, HO-1, and SOD2 expression while downregulating KEAP1. RES mitigates cognitive deficits in POCD by reducing neuroinflammation and oxidative stress through activation of the NRF2/HO-1 signaling pathway. These findings suggest RES is a potential therapeutic candidate for the treatment of POCD in elderly patients.

The immune-inflammatory responses on the hypothalamic-pituitary-adrenal axis and the neurovascular unit in perioperative neurocognitive disorder

Perioperative neurocognitive disorders (PNDs) refer to a wide spectrum of cognitive impairment persisting days to even after a year postoperative with significant morbidity and mortality. However, despite much efforts involving perioperative managements, PNDs are still prevalent with no standard preventative and therapeutic strategy. To overcome PNDs, a better understanding of pathophysiology of PNDs is crucial and a large number of studies have proven that immune-inflammatory responses from surgical stress are involved in the abnormal activation of the hypothalamic-pituitary-adrenal (HPA) axis and destabilization of neurovascular unit (NVU) that lead to PNDs. The HPA axis is one of the key components to maintaining physiological homeostasis in response to stress. Under normal conditions, the HPA axis is involved in multiple roles from memory consolidation to regulating the circadian rhythm by activating adrenal cortex to secret cortisol. However, when overwhelmed with inflammatory response from surgical stress, HPA axis may be abnormally activated to release excessive glucocorticoids to cause PNDs. In addition, NVU, the functional unit of the brain essential for maintaining blood brain barrier and cerebral blood flow, is another possible factor that may lead to PNDs as compromised NVU from inflammatory response can result in disrupted blood brain barrier and impaired brain homeostasis. Therefore, the interaction of immune-inflammatory response with the HPA axis and the NVU seems to play a significant role and therapeutic and/or preventive strategies focused on these interactions may be promising direction for future managements of PNDs.

School Performance and Learning Challenges in Children and Adolescents with Congenital Heart Disease

Children with congenital heart disease are at risk for neurocognitive and neurodevelopmental challenges, learning disabilities, and psychosocial difficulties. Our narrative review draws literature-based evidence for the effect of congenital heart disease on school performance. We conducted a literature review and extracted relevant articles from Google Scholar, Medline, and PubMed. Evidence showcases that school performance is impacted directly by congenital heart disease. This seems to be underlined by different factors inherent to congenital heart disease, like inattention, language difficulties, and decreased fine and gross motor skills. Moreover, the operative and postoperative periods present various physical challenges that can hinder development, ultimately affecting daily activities and quality of life. The consequent stressors in childhood can have long-lasting effects, leading to an increased prevalence of anxiety and depression affecting patients as they transition into adolescence and adulthood and placing significant social and emotional burdens on their direct environment. Children with congenital heart disease face both direct and indirect challenges related to their disease. These challenges are most likely to be the source of poor school performance and learning, as suggested by the literature. Close monitoring, early interventions, and multidisciplinary care are essential to address these vulnerabilities and improve educational outcomes in children with congenital heart disease.

Evaluating the relationship between inflammatory markers and preoperative delirium in elderly hip fracture patients: A retrospective observational study

Preoperative delirium is common and associated with poor clinical outcomes in elderly hip fracture patients. Although inflammatory markers have shown potential in predicting postoperative delirium, their relevance to preoperative delirium remains unclear. This study aimed to investigate the relationship between inflammatory markers and preoperative delirium to improve risk prediction and management strategies. We retrospectively studied 548 elderly hip fracture patients aged 70 years or older. The primary outcome was preoperative delirium diagnosed using the Confusion Assessment Method (CAM). Explanatory variables included inflammatory markers (neutrophil-to-lymphocyte ratio [NLR], platelet-to-lymphocyte ratio [PLR], systemic immune-inflammation index [SII], inflammatory burden index [IBI], and systemic inflammation response index [SIRI]). About 7.66% of patients developed preoperative delirium in the study. These patients were more likely to be older, have comorbid cardiovascular disease, and be transferred to an internal medicine ward for further treatment (P < .001). Multivariate analysis further revealed that older age (OR = 1.11, 95% CI = 1.04-1.18) and comorbid cardiovascular disease (OR = 2.94, 95% CI = 1.51-5.67) were independently associated with the occurrence of preoperative delirium. No significant differences were observed between groups for inflammatory markers: NLR (P = .70), PLR (P = .09), IBI (P = .09), SII (P = .21), or SIRI (P = .80). Older age and cardiovascular comorbidities were independent risk factors for preoperative delirium. No significant associations were found with inflammatory markers. Future research should explore additional biomarkers to refine risk stratification in this population.

Impact of fracture fixation surgery on cognitive function and the gut microbiota in mice with a history of stroke

Perioperative cognitive dysfunction is a common complication in stroke patients undergoing secondary surgeries. This study investigated the effects of tibial fracture internal fixation (TFIF) surgery on cognitive function and the gut microbiota in mice with a history of stroke. Using the middle cerebral artery occlusion method to induce stroke, we assessed cognitive function via the fear conditioning test and analyzed the gut microbiota through 16S rRNA sequencing. Compared with those in the normal and stroke groups, the cognitive function of the mice in the stroke group that underwent TFIF surgery was significantly impaired. Gut microbiota analysis revealed significant changes in beta diversity, but not in alpha diversity, in these mice. Additionally, TFIF surgery increased microglial activation and IL-1β and lipopolysaccharide (LPS) levels in the brain while reducing α-defensin levels and increasing IL-1β and LPS levels in the colon. These results suggest that TFIF surgery exacerbates cognitive impairment in stroke mice, possibly through alterations in the gut microbiota that impair intestinal defense and promote inflammation. This study highlights the critical role of the gut microbiome in cognitive function and perioperative outcomes, offering insights into potential therapeutic strategies for perioperative cognitive dysfunction in stroke patients.

Minimally Invasive vs. Open Synovectomy in Rheumatoid Arthritis: Insights into Clinical Recovery, Systemic Inflammation, and Economic Impact

Background: Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by persistent synovial inflammation, leading to joint destruction and disability. Synovectomy, the surgical removal of inflamed synovial tissue, is performed when pharmacological treatments are insufficient. This study compares the clinical efficacy, systemic inflammatory response, and cost-effectiveness of minimally invasive arthroscopic synovectomy versus traditional open synovectomy in RA patients. Methods: A comparative observational study was conducted on 53 RA patients undergoing either arthroscopic (n = 30) or open synovectomy (n = 23) at "Pius Brînzeu" Timișoara County Emergency Clinical Hospital over nine years. Clinical outcomes, including pain relief (VAS), functional improvement (HAQ), complication rates, and recovery times, were assessed at baseline, 1, 3, 6, and 12 months postoperatively. Systemic inflammatory markers (CRP, IL-6, TNF-α, ESR, and fibrinogen) were measured preoperatively, at 48 h and 30 days postoperatively. A cost-effectiveness analysis evaluated direct and indirect healthcare costs. Results: Arthroscopic synovectomy demonstrated significantly faster pain reduction and functional recovery within the first three months (p < 0.001), shorter hospital stays (3.1 vs. 6.4 days, p < 0.001), and quicker returns to daily activities (14.5 vs. 22.3 days, p < 0.001) compared to open synovectomy. Inflammatory markers were significantly lower postoperatively in the arthroscopic group (p < 0.01), indicating reduced systemic inflammation. Complication rates were markedly lower in the arthroscopic group (26.66% vs. 82.60%, p < 0.001). Despite higher procedural costs, arthroscopic synovectomy proved more cost-effective due to reduced hospitalization and faster recovery. Conclusions: Arthroscopic synovectomy offers superior early postoperative outcomes, reduced systemic inflammation, and greater cost-effectiveness compared to open synovectomy, with comparable long-term joint stability. These findings support its preference as the surgical technique of choice for RA patients requiring synovectomy.

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.

Brain Structural and Functional Changes Associated With Postoperative Neurocognitive Disorders: Research Update

Postoperative neurocognitive disorders (PNDs) are frequent and serious perioperative complications in the elderly, and are associated with increased morbidity and mortality, length of hospital stay, and need for long-term care. At present, the pathogenesis of PND is not completely clear, and there are various risk factors including surgical trauma and stress mediating systemic inflammation towards neuroinflammation development which causes brain structural and functional changes namely PND. For elderly patients, perioperative neurological monitoring may provide insights into brain function status. Monitoring may also help clinicians identify potential risks which would ultimately allow timely and effective intervention for better perioperative safety and prognosis for elderly patients. In this review, we summarize the risk factors and potential mechanisms of PND, and discuss preliminary evidence regarding application of electroencephalography, functional near-infrared spectroscopy, functional magnetic resonance, and positron emission tomography imaging in monitoring the central nervous system during the postoperative period.

The Role of Cytokines in Perioperative Neurocognitive Disorders: A Review in the Context of Anesthetic Care

Perioperative neurocognitive disorders (PNDs), including postoperative delirium, delayed neurocognitive recovery, and long-term postoperative neurocognitive disorders, present significant challenges for older patients undergoing surgery. Inflammation is a protective mechanism triggered in response to external pathogens or cellular damage. Historically, the central nervous system (CNS) was considered immunoprivileged due to the presence of the blood-brain barrier (BBB), which serves as a physical barrier preventing systemic inflammatory changes from influencing the CNS. However, aseptic surgical trauma is now recognized to induce localized inflammation at the surgical site, further exacerbated by the release of peripheral pro-inflammatory cytokines, which can compromise BBB integrity. This breakdown of the BBB facilitates the activation of microglia, initiating a cascade of neuroinflammatory responses that may contribute to the onset of PNDs. This review explores the mechanisms underlying neuroinflammation, with a particular focus on the pivotal role of cytokines in the pathogenesis of PNDs.

Efficacy of electroacupuncture for insomnia in cancer patients: a systematic review and meta-analysis

Background

Insomnia is a prevalent symptom among cancer patients. Electroacupuncture (EA) has been widely applied in managing sleep disorders, particularly in cancer patients or those experiencing insomnia.

Objectives

This meta-analysis aims to evaluate the efficacy and safety of electroacupuncture for treating cancer-related insomnia.

Methods

Two independent reviewers conducted comprehensive searches across multiple databases, including EMBASE, Web of Science, PubMed, the Cochrane Library, Wanfang Digital Journals, China National Knowledge Infrastructure (CNKI), and the VIP Database for Chinese Technical Periodicals. The search was completed on April 28, 2024. The reviewers independently performed literature screening, data extraction, and risk of bias (ROB) assessment using the revised Cochrane ROB tool. Data were analyzed using RevMan 5.4 and Stata 15.0 software.

Results

Eight randomized controlled trials (RCTs) involving 550 patients (305 in the experimental group and 245 in the control group) were included. EA significantly reduced Pittsburgh Sleep Quality Index (PSQI) scores (SMD = -0.86, 95% CI [-1.24, -0.49], p < 0.001), Insomnia Severity Index (ISI) scores (SMD = -1.14, 95% CI [-1.59, -0.69], p < 0.001), sleep latency (SL) (SMD = -0.48, 95% CI [-0.73, -0.23], p < 0.001), and sleep disturbance (SDB) (SMD = -0.44, 95% CI [-0.73, -0.16], p = 0.002). EA also significantly lowered Hospital Anxiety and Depression Scale-Anxiety (HADS-Anxiety) scores (SMD = -0.59, 95% CI [-0.91, -0.26], p < 0.001) and Hospital Anxiety and Depression Scale-Depression (HADS-Depression) scores (SMD = -0.73, 95% CI [-1.06, -0.40], p < 0.001), while increasing total sleep time (TST) (SMD = 0.65, 95% CI [0.14, 1.17], p = 0.013). No significant differences were observed in the Athens Insomnia Scale (AIS), sleep duration (SD), sleep efficiency (SE), or sleep quality (SQ) scores between the EA and control groups.

Conclusion

Electroacupuncture has shown promising potential in treating cancer-related insomnia by increasing total sleep time and reducing sleep disturbances. However, additional high-quality studies are necessary to validate these findings.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=567567, Identifier CRD42024567567.

CD33 Ameliorates Surgery-Induced Spatial Learning and Memory Impairments Through TREM2

Neuroinflammation is implicated in the onset of postoperative cognitive dysfunction (POCD), with CD33 and triggering receptor expressed on myeloid cells 2 (TREM2) playing crucial roles in immune response modulation and neuroinflammatory processes. A total of 96 aged male C57/BL6 mice (9-12 months) were randomly assigned to one of four groups, each receiving an siRNA injection into the lateral ventricle. Subsequently, the mice underwent partial hepatectomy under general anesthesia. To assess cognitive function, the Morris water maze tests were conducted both pre- and post-surgery. Following behavioral assessments, hippocampal tissues were swiftly harvested. The regulation of CD33 and TREM2 expression was achieved through siRNA in the BV2 microglia cell line. Expression levels of CD33 and TREM2 were evaluated both in vitro and in vivo using quantitative RT-PCR and western blot analyses. This study explored the impact of CD33 and TREM2 on POCD in aged mice and revealed that surgery and anesthesia increased CD33 expression, leading to spatial learning and memory impairments. Inhibiting CD33 expression via siRNA administration ameliorated cognitive deficits and mitigated the neuroinflammatory response triggered by surgery. Additionally, CD33 inhibition reversed the surgery-induced decrease in synaptic-related proteins, highlighting its role in preserving synaptic integrity. Moreover, our experiments suggest that CD33 may influence neuroinflammation and cognitive function through mechanisms involving TREM2. This is evidenced by the suppression of pro-inflammatory cytokines following CD33 knockdown in microglia and the reversal of these effects when both CD33 and TREM2 are concurrently knocked down. These findings imply that CD33 might promote neuroinflammation by inhibiting TREM2. This study highlights the potential of targeting CD33 as a promising therapeutic strategy for preventing and treating POCD. It provides valuable insights into the intricate mechanisms underlying cognitive dysfunction following surgical procedures.

Cardiac surgery with valve replacement temporarily disrupts the hippocampal memory network

BACKGROUND

Systemic inflammation after heart valve replacement surgery commonly results in complications including cognitive impairment. This study was designed to investigate whether valvular heart disease itself and inflammation after valve replacement surgery affects cognition and the related functional connectivity (FC) of the hippocampal memory network.

METHODS

Forty-three patients with valvular heart disease were screened for recruitment and assessed with cognition function tests, blood inflammatory cytokine measurements, and functional magnetic resonance imaging scans before surgery and on postoperative day 7 and 30. Age- and sex-matched healthy controls (n=30) were recruited for comparison. The brain FC networks using the hippocampus as a seed were analysed. Bivariate correlation and structural equation model analyses were carried out to investigate the association between altered FC, memory, and inflammation.

RESULTS

Thirty-five patients and 29 healthy controls completed the study, and their data were finally analysed and reported. Compared with healthy controls, the surgery group had increased FC in the bilateral precuneus and middle cingulate and paracingulate gyri before surgery. They exhibited impaired memory, increased plasma concentrations of proinflammatory cytokines, and decreased hippocampal FC at postoperative day 7. At 30 days after surgery, the FC abnormalities seen before surgery and at postoperative day 7 were restored to the level comparable with the healthy controls. High systemic inflammation was significantly associated with worse memory and lower FC in the hippocampal memory network.

CONCLUSIONS

Valve replacement surgery temporarily disrupts the hippocampal memory network with transient associated memory decline.

CLINICAL TRIAL REGISTRATION

ChiCTR2300069614.

Prevalence and risk factors of subsyndromal delirium in ICU: A systematic review and meta-analysis

OBJECTIVE

To systematically assess the prevalence and risk factors for subsyndromal delirium (SSD) in the intensive care unit.

DESIGN

A systematic reviewand meta-analysis.

METHODOLOGY

This systematic review and meta-analysis was conducted in eight databases, including PubMed, Web of Science, Ovid,Scopus, China Knowledge Resource Integrated Database, Wanfang Database,Weipu Database and Chinese Biomedical Database. All original observational studies of subsyndromal delirium in the ICU were included, with languages limited to English and Chinese. The methodological quality was assessed by the Newcastle-Ottawa Scale and the Agency for Healthcare Research and Quality recommendation checklist. Meta-analysis was performed using Stata software (version 18.0).

RESULT

A total of 27 studies involving 7,286 participants were included in this review. The pooled prevalence of SSD was 32.4 % (95 %CI: 27.1 %-37.7 %).Fourteen studies reported 34 independent risk factors, and the following ten factors were significantly associated with SSD: older age, higher Acute Physiology and Chronic Health Evaluation II (APACHE II) score, lower Mini-mental Status Examination (MMSE) score, pain, mechanical ventilation, hypoproteinemia, blood transfusion, longer ICU stay, infection, and physical restraint.

CONCLUSION

We conducted a systematic review and meta-analysis to evaluate the prevalence of SSD in the ICU and identified 10 risk factors associated with SSD. However, the studies have significant heterogeneity, future research should be conducted in multicenter with large samples to strengthen the current evidence.

IMPLICATIONS FOR CLINICAL PRACTICE

Subsyndromal delirium is a frequently occurring adverse event in the ICU, so it is recommended that clinicians and nurses incorporate the assessment of SSD into their daily routine. In this study, we also identified ten risk factors associated with SSD, and some of which could be modified or intervened. These findings provide a basis for ICU medical staff to identify patients at high risk of SSD and then implement individualized interventions to reduce the prevalence of SSD.

Remimazolam attenuates lipopolysaccharide-induced neuroinflammation and cognitive dysfunction

OBJECTIVE

Remimazolam, a novel benzodiazepine, is widely used as an anesthetic in endoscopic procedures; however, its effects on cognitive function remain unclear, limiting its broader application in general anaesthesia. Neuroinflammation is a well-established key factor in the etiology and progression of cognitive dysfunction, including conditions such as Alzheimer's disease, Parkinson's disease, postoperative delirium, and postoperative cognitive dysfunction. Preclinical studies have demonstrated that remimazolam exerts anti-inflammatory and neuroprotective effects, and clinical reports indicate a reduced incidence of postoperative delirium in patients treated with remimazolam. Nevertheless, whether remimazolam improves cognitive function through its anti-inflammatory properties remains uncertain. This study aimed to investigate the neuroprotective effects of remimazolam and its underlying mechanism in a lipopolysaccharide (LPS)-induced model of neuroinflammation, neuronal injury, and cognitive dysfunction METHODS: C57BL/6 J male mice were administered LPS intraperitoneally to establish a model of neuroinflammation-induced cognitive impairment. A subset of mice received remimazolam via intraperitoneal injection 30 minutes prior to LPS administration. Cognitive performance was evaluated using behavioural tests, including the Morris Water Maze (MWM), Novel Object Recognition (NOR) test, and Open Field Test (OFT). Hippocampal tissues were analyzed by haematoxylin-eosin (HE) staining to assess structural changes. Inflammatory markers, including Interleukin (IL)-6, IL-1β, and tumor necrosis factor-α, were quantified using enzyme-linked immunosorbent assay (ELISA) and real-time quantitative PCR. Immunofluorescence was used to detect translocator protein (TSPO) and markers of microglia activation (IBA-1, CD16/32, and CD206).

RESULTS

(1) Remimazolam reversed LPS-induced cognitive deficits, as evidenced by shorter spatial exploration latency and increased platform crossings in the MWM, and an elevated recognition index in the NOR test. (2) Remimazolam improved hippocampal morphology, reducing LPS-induced neuronal damage. (3) Remimazolam significantly decreased levels of hippocampal inflammatory cytokines, inhibited microglial activation, promoted M2-type microglia polarization, and increased TSPO expression.

CONCLUSION

Remimazolam demonstrated neuroprotective and anti-neuroinflammatory effects in a mouse model of LPS-induced cognitive impairment. These effects are likely mediated through the regulation of TSPO, which inhibits microglial activation and promotes the polarization of microglia from the pro-inflammatory M1 phenotype to the anti-inflammatory M2 phenotype.

Cognitive disorders: Potential astrocyte-based mechanism

Cognitive disorders are a common clinical manifestation, including a deterioration in the patient's memory ability, attention, executive power, language, and other functions. The contributing factors of cognitive disorders are numerous and diverse in nature, including organic diseases and other mental disorders. Neurodegenerative diseases are a common type of organic disease related to the pathology of neuronal death and disruption of glial cell balance, ultimately accompanied with cognitive impairment. Thus, cognitive disorder frequently serves as an extremely critical indicator of neurodegenerative disorders. Cognitive impairments negatively affect patients' daily lives. However, our understanding of the precise pathogenic pathways of cognitive defects remains incomplete. The most prevalent kind of glial cells in the central nervous system are called astrocytes. They have a unique significance in cerebral function because of their wide range of functions in maintaining homeostasis in the central nervous system, regulating synaptic plasticity, and so on. Dysfunction of astrocytes is intimately linked to cognitive disorders, and we are attempting to understand this phenomenon predominantly from those perspectives: neuroinflammation, astrocytic senescence, connexin, Ca2 + signaling, mitochondrial dysfunction, and the glymphatic system.

tsRNA-5006c regulates hippocampal neurons ferroptosis to ameliorate perioperative neurocognitive disorders in aged male mice

The aim of this research is to investigate whether ferroptosis occurs in the pathogenesis of perioperative neurocognitive disorders (PND), and to explore the function and underlying molecular mechanism of tsRNA in the regulation of ferroptosis in PND. A PND aged mice model was established and behavioral changes and ferroptosis occurrence were confirmed. The effect of ferroptosis inhibitor ferrostatin-1 (Fer-1) on PND mice was detected. tsRNA expression profile in PND mice and the effect of tsRNA on ferroptosis in vitro were perfomed. We found that anxious exploration behavior and short-term working memory was declined in PND mice compared with control mice, and the levels of S100β and IL-6 were increased. Meanwhile, hippocampal neurons of PND mice were damaged and accompanied by ferroptosis. Fer-1 can improve cognitive impairment in PND mice, as reflected by improved anxious exploration behavior and short-term working memory, and the levels of S100β and IL-6 were decreased. The expression profile of tsRNA in PND mice is disordered, and the dysregulated tsRNAs were mainly enriched in biologic functions related to neuronal development and ferroptosis. The tsRNA-5006c, identified as a pivotal player, significantly suppressed ferroptosis in primary mice neurons. This study shows for the first time that the pathophysiological process of PND is accompanied by ferroptosis of neurons, and reveals that tsRNA-5006c regulates ferroptosis of hippocampal neurons to ameliorate PND, which is of great significance for the development of new treatment strategies.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-024-04176-3.

Bibliometric Analysis of Neuroinflammation and Postoperative Cognitive Dysfunction

BACKGROUND

The occurrence and development of postoperative cognitive dysfunction (POCD) are closely linked to neuroinflammation. This bibliometric analysis aims to provide novel insights into the research trajectory, key research topics, and potential future development trends in the field of neuroinflammation-induced POCD.

METHODS

The Web of Science Core Collection (WoSCC) database was searched to identify publications from 2012 to 2023 on neuroinflammation-induced POCD. Bibliometric analysis, involving both statistical and visual analyses, was conducted using CiteSpace, VOSviewer, and the R software.

RESULTS

Research on neuroinflammation-induced POCD has exhibited an increasing trend over the past 12 years. China had the highest number of publications, Nanjing Medical University had the most collaboration with other institutions, Zhiyi Zuo was the most published author, and the Journal of Neuroinflammation served as the primary publication in the field of neuroinflammation-induced POCD. The most frequent keyword was POCD. Keyword clustering analysis indicated that the predominant cluster is dexmedetomidine. Burst detection revealed that postoperative delirium (POD), perioperative neurocognitive disorders (PND), apoptosis, and epigenetic modifications were the future research trends.

CONCLUSIONS

Our analysis identified the following key research areas associated with neuroinflammation-induced POCD: anesthesia, surgery, dexmedetomidine, NLRP3 inflammasome, and mechanism of neuroinflammation-induced POCD. The potential future research topics comprise POD, PND, apoptosis, and epigenetic modifications.

Efficacy of repetitive transcranial magnetic stimulation in preventing postoperative delirium in elderly patients undergoing major abdominal surgery: A randomized controlled trial

BACKGROUND

Postoperative delirium (POD) is a serious complication in elderly patients after major surgery, associated with high morbidity and mortality. Treatment and prevention methods are limited. Repetitive transcranial magnetic stimulation (rTMS) shows potential in enhancing cognitive function and improving consciousness.

OBJECTIVE

To evaluate whether early postoperative rTMS has a protective effect against POD and to explore its potential mechanisms.

METHODS

Patients aged 60 years or older, scheduled for major abdominal surgery, were randomly assigned to receive rTMS at 100 % RMT, 10 Hz, with 2000 pulses targeting the DLPFC after extubation in PACU, either as active rTMS(n = 61) or sham rTMS (n = 61). The primary outcome was the incidence of POD during the first 3 postoperative days.

RESULTS

In the modified intention-to-treat analysis of 122 patients (mean [SD] age, 70.2 [4.1] years; 53.3 % women), POD incidence was lower in the rTMS group (11.5 %) compared to the sham rTMS group (29.5 %) (relative risk, .39; 95 % CI, .18 to .86; P = .01). rTMS patients had higher BDNF (8.47 [2.68] vs. 5.76 [1.42] ng/mL; P < .001) and lower NfL (.05 [.04] vs. .06 [.04] ng/mL; P = .02) levels. Mediation analysis suggests that rTMS may reduce POD by increasing brain-derived neurotrophic factor (z = -3.72, P < .001) rather than decreasing neurofilament light (z = 1.92, P = .06).

CONCLUSIONS

Immediate postoperative rTMS can reduce the incidence of POD in elderly patients undergoing major abdominal surgery, probably by upregulating brain-derived neurotrophic factor levels.

Double negative T cells promote surgery-induced neuroinflammation, microglial engulfment and cognitive dysfunction via the IL-17/CEBPβ/C3 pathway in adult mice

CD3(+) CD4(-) CD8(-) double negative T cells (DNTs) manifest themselves in autoimmune diseases and associated inflammation. In the central nervous system, the increased presence of DNTs is associated with the progression of neurological conditions and brain injury. Active DNTs that produce IL-17 have been regarded as a pro-inflammatory phenotype. The IL-17 signaling pathway mediates neuroinflammatory responses by inducing glial activation and producing inflammatory factors. Neuroinflammation is considered integral to the pathogenesis of perioperative neurocognitive disorders (PNDs), commonly developed after surgery in susceptible patients. We and others have demonstrated a significant role for complement C3 in surgery-induced neuroinflammation and cognitive impairment but the regulatory mechanisms for this remain unexplored. We hypothesized that surgery induces DNT infiltration into the CNS that in turn upregulates complement C3 expression and this causes changes that contribute to cognitive impairment. Using an adult murine abdominal surgery model, we investigated perioperative changes in cognitive performance, quantifying the presence of T cell subsets and phenotype, IL-17 signaling pathway activation, glial cell activation and C3 expression in the brain. Postoperative IL-17 specific inhibitor GSK2981278 administration or preoperatively conditional CEBPβ knock-down by AAV9 viral vector were then applied to evaluate the effect of inhibiting IL-17 signaling pathway on postoperative C3 expression and cognitive performance. The results showed an increased hippocampus infiltration of DNTs with augmented IL-17 production, along with C3 upregulation and cognitive impairment. Both inhibition of IL-17 or knock-down of CEBPβ significantly suppressed C3 expression, synaptic engulfment by microglia and attenuated cognitive impairment. These findings indicate that DNTs promote postoperative neuroinflammation and cognitive impairment via the IL-17/CEBPβ/C3 pathway and targeting this IL-17 axis could be a potential therapeutic strategy to ameliorate postoperative neuroinflammation and cognitive impairment.

Hippocampal Nogo66-NgR1 signaling activation restricts postsynaptic assembly in aged mice with postoperative neurocognitive disorders

Postoperative neurocognitive disorders (pNCD) are a common neurological complication, especially in elderly following anesthesia and surgery. Yet, the underlying mechanisms of pNCD remain elusive. This study aimed to investigate the molecular mechanisms that compromise synaptic metaplasticity in pNCD development with a focus on the involvement of Nogo-66 receptor 1 (NgR1) in the pathogenesis of pNCD in aged mice. Aged mice subjected to anesthesia and laparotomy surgery exhibited anxiety-like behavior and contextual fear memory impairment. Moreover, the procedure significantly increased NogoA and NgR1 expressions, particularly in the hippocampal CA1 and CA3 regions. This increase led to the depolymerization of F-actin, attributed to the activation of the RhoA-GTPase, resulting in a reduction of dendritic spines and changes in their morphology. Additionally, these changes hindered the efficient postsynaptic delivery of the subunit GluA1 and GluA2 of AMPA receptors (AMPARs), consequently diminishing excitatory neurotransmission in the hippocampus. Importantly, administering the competitive NgR1 antagonist peptide NEP1-40 (Nogo-A extracellular peptide residues 1-40 amino acids of Nogo-66) and Fasudil (a Rho-kinase inhibitor) effectively mitigated synaptic impairments and reversed neurocognitive deficits in aged mice following anesthesia and surgery. Our work indicates that high hippocampal Nogo66-NgR1 signaling disrupts postsynaptic AMPA receptor surface delivery due to F-actin depolymerization in the pathophysiology of pNCD.

Quantitative electroencephalography predicts postoperative delirium in adult cardiac surgical patients from a prospective observational study

The diagnostic and prognostic value of quantitative electroencephalogram (qEEG) in the the onset of postoperative delirium (POD) remains an area of inquiry. We aim to determine whether qEEG could assist in the diagnosis of early POD in cardiac surgery patients. We prospectively studied a cohort of cardiac surgery patients undergoing qEEG for evaluation of altered mental status. Delirium was assessed with the Confusion Assessment Method for the intensive care unit (CAM-ICU). The qEEG were interpreted by clinician, and reports were reviewed to identify features such as amplitude-integrated EEG (aEEG), relative band energy in ɑ/β/θ/δ frequencies, α variability and spectral entropy. The raw EEG was also preprocessed offline for nonlinear analysis including Multi-scale Entropy analysis (MSE) and Detrended Fluctuation Analysis (DFA). Linear regression was performed to quantify associations among EEG findings, delirium, and clinical outcomes. Receiver operating characteristic (ROC) analysis was used to assess the accuracy of the qEEG as POD prediction index. Meanwhile, a comprehensive comparison of dynamic complexity across time scales and DFA exponent α was conducted between the non-delirium and delirium groups. Among those recruited initially (n = 64), 60 patients were evaluated and 29 patients (48.3%) met delirium criteria. When comparing delirious and non-delirious participants, significant differences were found in terms of age (p = 0.03), APACHE II scores (p = 0.004), lactate (p = 0.03), and hospital days (p = 0.048). Multivariate regression analysis revealed that the first quartile (Q1) and fourth quartile (Q4) of peak or valley value of F3-P3/F4-P4 derivation (for example, Q1 of peak value for F3-P3 derivation: OR 12.4, 95% CI 1.72-89.76, p = 0.012) showed a higher association with the incidence of POD. ROC analysis demonstrated qEEG could predict POD with high sensitivity and specificity, yielding an overall good accuracy. For instance, the peak value of F3-P3 derivation (the area under the curve of 0.81), as a predictor of POD showed a sensitivity of 90% and specificity pf 72% (p < 0.001). Furthermore, the MSE curves indicated that the non-delirium group exhibited higher complexity values at fine scales, while the delirium group had significantly higher complexity at coarse scales. The DFA comparison results revealed that long-term fractal exponent alpha2 values were higher in delirium patients than in non-delirium patients, with significant differences observed at the F4-P4 electrodes (p = 0.04). The qEEG can reliably predict delirium after heart cardiac surgery. It is helpful for clinicians to early diagnose and manage these patients.Trial registration: Clinical Trials.gov Identifier, NCT03351985. Registered 1 December 2017.

Effects of remimazolam and surgery on cognition in a tibia fracture mouse model

BACKGROUND

To investigate the effects of remimazolam and surgery on cognitive function and neuropathology.

METHODS

We performed intramedullary pin fixation of tibial fractures in wild-type male (12-13-week-old) C57BL/6J mice under intraperitoneal anesthesia with remimazolam. Age-matched wild-type control mice received either saline or remimazolam without surgery. Training was performed 1 h before surgery, and the open field test was performed on the third postoperative day, in addition to trace fear conditioning on the third versus the seventh day and the Y maze test on the fourth versus the eighth day. Phosphorylated tau (P-TAU) protein levels in hippocampal tissue, microglial activation, dendritic spine density in neuronal cells, and interleukin-6 (IL-6) levels were determined.

RESULTS

We detected no significant differences in locomotor ability among the three groups in the open field test on the third postoperative day; however, on the conditioned fear test or in the Y-maze, the cognitive related performance of the mice in the surgery group was significantly worse than that of the control group and the remimazolam group. However, there were no differences among the three groups in the behavioural experiments on the seventh and eighth days. In addition, mice in the surgery group had higher levels of P-TAU in their hippocampal tissue, more microglial activation, more significant changes in neuronal dendritic spine density, and higher levels of IL-6 in their hippocampal tissue compared with mice in the other two groups.

CONCLUSIONS

The cognitive dysfunction and neuropathological changes produced by remimazolam-based surgery are mainly of surgical origin and are not related to the use of remimazolam, a general anesthetic agent.

Current Progress on Postoperative Cognitive Dysfunction: An Update

Postoperative cognitive dysfunction (POCD) represents a significant clinical concern, particularly among elderly surgical patients. It is characterized by a decline in cognitive performance, affecting memory, attention, coordination, orientation, verbal fluency, and executive function. This decline in cognitive abilities leads to longer hospital stays and increased mortality. This review provides a comprehensive overview of the current progress in understanding the relevant pathogenic factors, possible pathogenic mechanisms, diagnosing, prevention and treatment of POCD, as well as suggesting future research directions. It discusses neuronal damage, susceptible genes, central cholinergic system, central nervous system (CNS) inflammation, stress response and glucocorticoids, and oxidative stress in the development of POCD, aiming to uncover the pathological mechanism and develop effective treatment strategies for POCD.

Progress and Frontiers of Research on Dexmedetomidine in Perioperative Medicine: A Bibliometric Analysis

Background

Dexmedetomidine has received increasing attention for its sedative, analgesic, anxiolytic, anti-inflammatory and anti-stress effects in perioperative medicine. Numerous studies have been carried out to explore its influence on perioperative patients.

Objective

This study aimed to identify the most influential literature, trends and hotspots in dexmedetomidine research by bibliometric analysis.

Methods

Articles and reviews related to dexmedetomidine in perioperative medicine were collected from Web of Science Core Collection. VOSviewer and Citespace software were used for bibliometric analysis and data visualization.

Results

A total of 1652 suitable publications were extracted from the database for analysis, including 1,497 articles and 155 reviews. The number of publications in the field of dexmedetomidine research has increased markedly since 2013, with China being the major contributor, followed by United States. BMC Anesthesiology published the highest number of papers on this topic. Anesthesiology ranked first in terms of average citations per paper and co-citation journal. Ji Fuhai was the most prolific author, and Ma Daqing was the most cited authors. The main hotspots during this period were "elderly patients", "postoperative cognitive dysfunction", "injury" and "risk factors".

Conclusion

This study presents an overview of the development related to dexmedetomidine in perioperative medicine using bibliometric analysis. Dexmedetomidine research is thriving and expanding rapidly around the world. The effect of dexmedetomidine on cognitive function has been the latest research hotspot. To advance research in this field, more rigorous and scientific multi-center studies should be designed and further cooperation and academic exchange should be strengthened.

The NF-κB pathway: Key players in neurocognitive functions and related disorders

Perioperative neurocognitive disorder (PND) is a common complication of surgical anesthesia, yet its precise etiology remains unclear. Neuroinflammation is a key feature of PND, influenced by both patient -related and surgical variables. The nuclear factor-κB (NF-κB) transcription factor family plays a critical role in regulating the body's immunological proinflammatory response, which is pivotal in the development of PND. Surgery and anesthesia trigger the activation of the NF-κB signaling pathway, leading to the initiation of inflammatory cascades, disruption of the blood-brain barrier, and neuronal injury. Immune cells and glial cells are central to these pathological processes in PND. Furthermore, this study explores the interactions between NF-κB and various signaling molecules, including Tlr4, P2X, α7-nAChR, ROS, HIF-1α, PI3K/Ak, MicroRNA, Circular RNA, and histone deacetylases, within the context of PND. Targeting NF-κB as a therapeutic approach for PND shows promise as a potential treatment strategy.

Acute changes in hippocampal metabolism after anesthesia and surgery: Implications for perioperative neurocognitive disorder

BACKGROUND

The risk of developing dementia is higher in individuals who suffer from perioperative neurocognitive disorder (PND), including postoperative cognitive dysfunction (POCD) and delirium. Recent studies have indicated correlations between anesthesia, surgery and PND. Acute metabolic changes induced by anesthesia and surgery may be related to cognitive impairments. Despite a paucity of research on acute metabolic changes in the hippocampus during surgery, there are conflicting about specific metabolites.

METHODS

We developed a mouse model of cognitive impairment induced by isoflurane anesthesia and unilateral nephrectomy. Cognition was evaluated by Y maze and fear conditioning test (FCT). The hippocampus was harvested after the surgery. LC-MS (liquid chromatography-mass spectrometry) was performed. The differential metabolites involved in lipid, amino acid, nucleotide, carbohydrate metabolism were analyzed.

RESULTS

Anesthesia and surgery exposure induced cognition decline. A total of 49 metabolites were significantly up-regulated and 122 down-regulated. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway of the metabolites identified purine, glutathione, nicotinate and nicotinamide metabolism. Metabolites involved in lipid, amino acid, nucleotide, carbohydrate metabolism were identified including nicotinamide adenine dinucleotide (NAD), 1-Methylnicotinamide, propionic acid, histidine, adenosine, and guanosine cyclic monophosphate. Some metabolites exhibited a consistent change trend in the hippocampus of aging mice.

CONCLUSIONS

The study indicates that anesthesia and surgery can induce acute alterations in hippocampal metabolomics, including metabolites involved in lipid, amino acid, nucleotide, and carbohydrate metabolism. These metabolites may play a role in modulating PND through the regulation of neuroinflammation, oxidative stress, blood-brain barrier (BBB) permeability.

An immune signature of postoperative cognitive decline: a prospective cohort study

BACKGROUND

Postoperative cognitive decline (POCD) is the predominant complication affecting patients over 60 years old following major surgery, yet its prediction and prevention remain challenging. Understanding the biological processes underlying the pathogenesis of POCD is essential for identifying mechanistic biomarkers to advance diagnostics and therapeutics. This study aimed to provide a comprehensive analysis of immune cell trajectories differentiating patients with and without POCD and to derive a predictive score enabling the identification of high-risk patients during the preoperative period.

MATERIAL AND METHODS

Twenty-six patients aged 60 years old and older undergoing elective major orthopedic surgery were enrolled in a prospective longitudinal study, and the occurrence of POCD was assessed 7 days after surgery. Serial samples collected before surgery, and 1, 7, and 90 days after surgery were analyzed using a combined single-cell mass cytometry and plasma proteomic approach. Unsupervised clustering of the high-dimensional mass cytometry data was employed to characterize time-dependent trajectories of all major innate and adaptive immune cell frequencies and signaling responses. Sparse machine learning coupled with data-driven feature selection was applied to the presurgery immunological dataset to classify patients at risk for POCD.

RESULTS

The analysis identified cell-type and signaling-specific immune trajectories differentiating patients with and without POCD. The most prominent trajectory features revealed early exacerbation of JAK/STAT and dampening of inhibitory κB and nuclear factor-κB immune signaling responses in patients with POCD. Further analyses integrating immunological and clinical data collected before surgery identified a preoperative predictive model comprising one plasma protein and 10 immune cell features that classified patients at risk for POCD with excellent accuracy (AUC=0.80, P =2.21e-02 U -test).

CONCLUSION

Immune system-wide monitoring of patients over 60 years old undergoing surgery unveiled a peripheral immune signature of POCD. A predictive model built on immunological data collected before surgery demonstrated greater accuracy in predicting POCD compared to known clinical preoperative risk factors, offering a concise list of biomarker candidates to personalize perioperative management.

Improvement of Isolated Abducens Nerve Palsy with Hydrocephalus after CSF Diversion: A Possible Evaluative Role of Retroclival-pontomedullary Distance

Isolated abducens nerve palsy (IANP), caused by secondary communicating hydrocephalus, has been rarely documented; in addition, its mechanism and appropriate treatment are not understood well. This study presents a case of bilateral IANP with hydrocephalus in a 62-year-old man who was successfully treated with cerebrospinal fluid (CSF) diversion to correct an enlarged retroclival space during the follow-up of recurrent brain tumor in the right parieto-occipital lobe. The patient was treated with three resections, temozolomide, and irradiation before developing IANP. Magnetic resonance imaging (MRI) revealed a recurrent tumor and ventriculomegaly with an expanded retroclival cisternal space. The patient underwent subtotal tumor resection and external ventricular drain placement in the anterior horn of the lateral ventricle. His bilateral IANP persisted for 4 days after surgery but gradually improved and disappeared by Day 7. Four weeks later, the patient underwent ventriculoperitoneal (VP) shunt surgery to establish a permanent CSF diversion that continued to control the symptoms. Retrospective MRI review revealed the distance between the clivus and pontomedullary junction on the sagittal section (retroclival-pontomedullary distance; RPD) of 9.0, 12.8, 10.7, and 10.6 mm before IANP, on IANP onset, on postoperative Day 4, and post VP shunt surgery, respectively. In conclusion, VP shunt surgery was an appropriate approach for IANP with communicating hydrocephalus to correct the enlarged retroclival cisternal space. RPD thus may be used as one of possible evaluation methods for IANP with hydrocephalus, which can be caused by various factors.

Preoperative Exposure to Fine Particulate Matter and Risk of Postoperative Complications: A Single Center Observational Cohort Bayesian Analysis

Background

While exposure to fine particulate matter air pollution (PM 2.5 ) is known to cause adverse health effects, its impact on postoperative outcomes in US adults remains understudied. Perioperative exposure to PM 2.5 may induce inflammation that interacts insidiously with the surgical stress response, leading to higher postoperative complications.

Methods

We conducted a single center, retrospective cohort study using data from 49,615 surgical patients living along Utah's Wasatch Front and who underwent elective surgical procedures at a single academic medical center from 2016-2018. Patients' addresses were geocoded and linked to daily Census-tract level PM 2.5 estimates. We hypothesized that elevated PM 2.5 concentrations in the week prior to surgery would be associated with an increase in a bundle of major postoperative complications. A hierarchical Bayesians regression model was fit adjusting for age, sex, season, neighborhood disadvantage, and the Elixhauser index of comorbidities.

Results

Postoperative complications increased in a dose-dependent manner with higher concentrations of PM 2.5 exposure, with a relative increase of 8% in the odds of complications (OR=1.082) for every 10ug/m 3 increase in the highest single-day 24-hr PM 2.5 exposure during the 7 days prior to surgery. For a 30 fold increase in PM 2.5 (1 ug/m 3 to 30ug/m 3 ) the odds of complication rose to over 27% (95%CI: 4%-55%). The association persisted after controlling for comorbidities and confounders; our inferences were robust to modeling choices and sensitivity analysis.

Conclusions

In this large Utah cohort, exposure to elevated PM 2.5 concentrations in the week before surgery was associated with a dose-dependent increase in postoperative complications, suggesting a potential impact of air pollution on surgical outcomes. These findings merit replication in larger datasets to identify populations at risk and define the interaction and impact of different pollutants. PM 2.5 exposure is a potential perioperative risk factor and, given the unmitigated air pollution in urban areas, a global health concern.

Asthma and cognitive dysfunction in older adults: the mediating role of systemic immune-inflammation index

Asthma and cognitive dysfunction represent significant public health challenges. Our study aimed to investigate the relationship between asthma and cognitive dysfunction in adults aged ≥ 60 years, and explore the role of systemic immune inflammation index (SII) in asthma - cognitive dysfunction link. The retrospective cross-sectional study included 2,579 participants aged ≥ 60 years from the 2011-2014 National Health and Nutrition Examination Survey (NHANES) cycles. Asthma diagnosis was confirmed using the MCQ010 questionnaire, cognitive function assessed through the Digit Symbol Substitution Test (DSST). SII was calculated using the formula: (platelet count × neutrophil count)/lymphocyte count. Controlling for demographic variables including sex, age, race and/ethnicity, poverty-to-income ratio (PIR) and education level, a negative association was found between asthma and DSST scores (β = -1.75, 95% CI: -3.38, -0.120, P = 0.037). This association persisted even after further adjustments for body mass index (BMI) and diabetes (β = -1.72, 95% CI: -3.38, -0.057, P = 0.043). Moreover, subgroup analysis showed no significant association of sex, age, race/ethnicity, BMI or diabetes with the relationship between asthma and cognitive function. Mediation analysis indicated SII was a mediator of asthma-induced cognitive impairment, a notable Average Causal Mediated Effect (ACME) (P = 0.004) between SII and cognitive dysfunction. Our investigation indicated that elderly asthma (aged ≥ 60 years) was predisposed to cognitive dysfunction, independent of sex, age, race/ethnicity, BMI and diabetes. Furthermore, mediation analysis suggested that asthma might contribute to cognitive dysfunction through the involvement of SII.

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 S100β 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.

Fecal microbiota transplantation alleviates cognitive impairment by improving gut microbiome composition and barrier function in male rats of traumatic brain injury following gas explosion

Background

Dysbiosis of gut microbiota (GM) is intricately linked with cognitive impairment and the incidence of traumatic brain injury (TBI) in both animal models and human subjects. However, there is limited understanding of the impact and mechanisms of fecal microbiota transplantation (FMT) on brain and gut barrier function in the treatment of TBI induced by gas explosion (GE).

Methods

We have employed FMT technology to establish models of gut microbiota dysbiosis in male rats, and subsequently conducted non-targeted metabolomics and microbiota diversity analysis to explore the bacteria with potential functional roles.

Results

Hematoxylin-eosin and transmission electron microscopy revealed that GE induced significant pathological damage and inflammation responses, as well as varying degrees of mitochondrial impairment in neuronal cells in the brains of rats, which was associated with cognitive decline. Furthermore, GE markedly elevated the levels of regulatory T cell (Tregs)-related factors interleukin-10, programmed death 1, and fork head box protein P3 in the brains of rats. Similar changes in these indicators were also observed in the colon; however, these alterations were reversed upon transfer of normal flora into the GE-exposed rats. Combined microbiome and metabolome analysis indicated up-regulation of Clostridium_T and Allobaculum, along with activation of fatty acid biosynthesis after FMT. Correlation network analysis indirectly suggested a causal relationship between FMT and alleviation of GE-induced TBI. FMT improved intestinal structure and up-regulated expression of tight junction proteins Claudin-1, Occludin, and ZO-1, potentially contributing to its protective effects on both brain and gut.

Conclusion

Transplantation of gut microbiota from healthy rats significantly enhanced cognitive function in male rats with traumatic brain injury caused by a gas explosion, through the modulation of gut microbiome composition and the improvement of both gut and brain barrier integrity via the gut-brain axis. These findings may offer a scientific foundation for potential clinical interventions targeting gas explosion-induced TBI using FMT.

Low blood S-methyl-5-thioadenosine is associated with postoperative delayed neurocognitive recovery

Elderly individuals display metabolite alterations that may contribute to development of cognitive impairment following surgery and anesthesia. However, these relationships remain largely unexplored. The study aims to assess the S-methyl-5-thioadenosine (MTA) is associated with postoperative delayed neurocognitive recovery (dNCR). We assess altered metabolites following anesthesia/surgery in both mice and patients to identify blood biomarkers of dNCR. Preoperative and postoperative plasma metabolites are determined by widely targeted metabolomics. The brains of mice with anesthesia/surgery show decreased MTA and activated MTA phosphorylase. Mice also show that preoperative administration of MTA can prevent inflammation and cognitive decline. In clinical patients, we detect lower preoperative serum MTA levels in those who developed dNCR. Both low preoperative and postoperative blood MTA levels are associated with increased risk of postoperative dNCR. These results suggest that anesthesia/surgery induces cognitive decline through methionine synthesis pathways and that MTA could be a perioperative predictor of dNCR.

Remimazolam ameliorates postoperative cognitive dysfunction after deep hypothermic circulatory arrest through HMGB1-TLR4-NF-κB pathway

BACKGROUND

Postoperative cognitive dysfunction (POCD) is a complication of deep hypothermic circulatory arrest (DHCA). Various amounts of neurologic dysfunctions have been shown after DHCA, which has often been attributed to systemic inflammatory response syndrome and cerebral ischemia/reperfusion injury. Remimazolam is one of the commonly used anesthetic drugs with protective actions against inflammatory diseases, such as sepsis and cerebral ischemia/reperfusion injury. Here, we determined the protective effect and potential mechanism of action of remimazolam against neuronal damage after DHCA.

METHODS

A rat model of DHCA was established, and a gradient dosage of remimazolam was administered during cardiopulmonary bypass (CPB). The cognitive function of rats was evaluated by Morris water maze. Hematoxylin and eosin and TUNEL staining were performed to assess hippocampus tissue injury and neuronal apoptosis. Inflammatory cytokines concentration were analyzed by enzyme-linked immunosorbent assay. The protein expression was analyzed using automated electrophoresis western analysis and immunohistochemical analysis.

RESULTS

The appropriate dosage of remimazolam reduced histologic injury, neuronal apoptosis, microglia activation, and secondary inflammatory cascades, as well as the downregulation of the expression of the HMGB1-TLR4-NF-κB pathway after DHCA, improved the memory and learning abilities in DHCA rats. Further, administration of a TLR4 antagonist TAK-242 had a similar effect to remimazolam, while the TLR4 agonist LPS attenuated the effect of remimazolam.

CONCLUSIONS

Remimazolam could ameliorate POCD after DHCA through the HMGB1-TLR4-NF-κB signaling pathway.

PDTC improves cognitive impairment in LPS-induced ARDS by regulating miR-181c/NF-κB axis-mediated neuroinflammation

BACKGROUND

Cognitive impairment is a severe complication of acute respiratory distress syndrome (ARDS). Emerging studies have revealed the effects of pyrrolidine dithiocarbamate (PDTC) on improving surgery-induced cognitive impairment. The major aim of the study was to investigate whether PDTC protected against ARDS-induced cognitive dysfunction and to identify the underlying mechanisms involved.

METHODS

The rat model of ARDS was established by intratracheal instillation of lipopolysaccharide (LPS), followed by treatment with PDTC. The cognitive function of rats was analyzed by the Morris Water Maze, and pro-inflammatory cytokines were assessed by quantitative real-time PCR, enzyme-linked immunosorbent assay, and western blot assays. A dual-luciferase reporter gene assay was performed to identify the relationship between miR-181c and its target gene, TAK1 binding protein 2 (TAB2).

RESULTS

The results showed that PDTC improved cognitive impairment and alleviated neuroinflammation in the hippocampus in LPS-induced ARDS model. Furthermore, we demonstrated that miR-181c expression was downregulated in the hippocampus of the ARDS rats, which was restored by PDTC treatment. In vitro studies showed that miR-181c alleviated LPS-induced pro-inflammatory response by inhibiting TAB2, a critical molecule in the nuclear factor (NF)-κB signaling pathway.

CONCLUSION

PDTC improves cognitive impairment in LPS-induced ARDS by regulating miR-181c/NF-κB axis-mediated neuroinflammation, providing a potential opportunity for the treatment of this disease.

Perioperative research into memory (PRiMe), part 2: Adult burns intensive care patients show altered structure and function of the default mode network

BACKGROUND

Long-term cognitive impairment (LTCI) is experienced by up to two thirds of patients discharged from burns intensive care units (BICUs), however little is known about its neurobiological basis. This study investigated if patients previously admitted to BICU showed structural and functional MRI changes of the Default Mode Network (DMN).

METHODS

Fifteen patients previously admitted to BICU with a significant burns injury, and 15 matched volunteers, underwent structural and functional MRI scans. Functional connectivity, fractional anisotropy and cortical thickness of the main DMN subdivisions (anterior DMN (aDMN), posterior DMN (pDMN) and right (rTPJ) and left (lTPJ) temporo-parietal junctions) were compared between patients and volunteers, with differences correlated against cognitive performance.

RESULTS

Functional connectivity between rTPJ and pDMN (t = 2.91, p = 0.011) and between rTPJ and lTPJ (t = 3.18, p = 0.008) was lower in patients compared to volunteers. Functional connectivity between rTPJ and pDMN correlated with cognitive performance (r2 =0.33, p < 0.001). Mean fractional anisotropy of rTPJ (t = 2.70, p = 0.008) and lTPJ (T = 2.39, p = 0.015) was lower in patients but there was no difference in cortical thickness.

CONCLUSIONS

Patients previously admitted to BICU show structural and functional disruption of the DMN. Since functional changes correlate with cognitive performance, this should direct further research into intensive-care-related cognitive impairment.

Gut Microbiota and Probiotics in Perioperative Management: A Narrative Review

The human gut is the abode of several complex and diverse microbes. It is a fact that the human brain is interconnected with the spinal cord and sense organs; however, there is also a possibility of a connection between the brain and the gut microbiome. The human gut can be altered in various ways, the principal method being the intake of prebiotics, probiotics and synbiotics. Can this alteration in the gut microbiome be clinically utilised in the perioperative period? We conducted a literature search related to this topic using databases and search engines (Medical Literature Analysis and Retrieval System Online {MEDLINE}, Embase, Scopus, PubMed and Google Scholar). The search revealed some preclinical and clinical studies in animals and humans that demonstrate the alteration of the gut microbiome with the use of anxiolysis, probiotics/prebiotics and other perioperative factors including opioids, anaesthetics and perioperative stress. The significant effects of this alteration have been seen on preoperative anxiety and postoperative delirium/cognitive dysfunction/pain. These effects are described in this narrative review, which opens up newer vistas for high-quality research related to the gut microbiome, gut-brain axis, the related signaling pathways and their clinical application in the perioperative period.

Blood-brain barrier disruption: a culprit of cognitive decline?

Cognitive decline covers a broad spectrum of disorders, not only resulting from brain diseases but also from systemic diseases, which seriously influence the quality of life and life expectancy of patients. As a highly selective anatomical and functional interface between the brain and systemic circulation, the blood-brain barrier (BBB) plays a pivotal role in maintaining brain homeostasis and normal function. The pathogenesis underlying cognitive decline may vary, nevertheless, accumulating evidences support the role of BBB disruption as the most prevalent contributing factor. This may mainly be attributed to inflammation, metabolic dysfunction, cell senescence, oxidative/nitrosative stress and excitotoxicity. However, direct evidence showing that BBB disruption causes cognitive decline is scarce, and interestingly, manipulation of the BBB opening alone may exert beneficial or detrimental neurological effects. A broad overview of the present literature shows a close relationship between BBB disruption and cognitive decline, the risk factors of BBB disruption, as well as the cellular and molecular mechanisms underlying BBB disruption. Additionally, we discussed the possible causes leading to cognitive decline by BBB disruption and potential therapeutic strategies to prevent BBB disruption or enhance BBB repair. This review aims to foster more investigations on early diagnosis, effective therapeutics, and rapid restoration against BBB disruption, which would yield better cognitive outcomes in patients with dysregulated BBB function, although their causative relationship has not yet been completely established.

Esketamine Prevents Postoperative Emotional and Cognitive Dysfunction by Suppressing Microglial M1 Polarization and Regulating the BDNF-TrkB Pathway in Ageing Rats with Preoperative Sleep Disturbance

Postoperative depression (POD) and postoperative cognitive dysfunction (POCD) have placed heavy burden on patients' physical and mental health in recent years. Sleep disturbance before surgery is a common phenomenon that has been increasingly believed to affect patients' recovery, especially in aged patients, while little attention has been paid to sleep disruption before surgery and the potential mechanism remains ambiguous. Ketamine has been reported to attenuate POCD after cardiac surgery and elicit rapid-acting and sustained antidepressant actions. The present study aimed to clarify the effect of esketamine's (the S-enantiomer of ketamine) protective effects and possible mechanisms of action in POCD and POD. Our results showed that sleep disturbance before surgery exacerbated microglial M1 polarization and microglial BDNF-TrkB signalling dysfunction induced by surgery, resulting in postoperative emotional changes and cognitive impairments. Notably, treatment with esketamine reversed the behavioural abnormalities through inhibiting the M1 polarization of microglia and the inflammatory response thus improving BDNF-TrkB signalling in vivo and vitro. In addition, esketamine administration also reversed the impaired hippocampal synaptic plasticity which has been perturbed by sleep disturbance and surgery. These findings warrant further investigations into the interplay of esketamine and may provide novel ideas for the implication of preoperative preparations and the prevention of postoperative brain-related complications.

Preoperative ketamine administration for prevention of postoperative neurocognitive disorders after major orthopedic surgery in elderly patients: A multicenter randomized blinded placebo-controlled trial

BACKGROUND

Preventive anesthetic impact on the high rates of postoperative neurocognitive disorders in elderly patients is debated. The Prevention of postOperative Cognitive dysfunction by Ketamine (POCK) study aimed to assess the effect of ketamine on this condition.

METHODS

This is a multicenter, randomized, double-blind, interventional study. Patients ≥60 years undergoing major orthopedic surgery were randomly assigned in a 1:1 ratio to receive preoperative ketamine 0.5 mg/kg as an intravenous bolus (n = 152) or placebo (n = 149) in random blocks stratified according to the study site, preoperative cognitive status and age. The primary outcome was the proportion of objective delayed neurocognitive recovery (dNR) defined as a decline of one or more neuropsychological assessment standard deviations on postoperative day 7. Secondary outcomes included a three-month incidence of objective postoperative neurocognitive disorder (POND), as well as delirium, anxiety, and symptoms of depression seven days and three months after surgery.

RESULTS

Among 301 patients included, 292 (97%) completed the trial. Objective dNR occurred in 50 (38.8%) patients in the ketamine group and 54 (40.9%) patients in the placebo group (OR [95% CI] 0.92 [0.56; 1.51], p = 0.73) on postoperative day 7. Incidence of objective POND three months after surgery did not differ significantly between the two groups nor did incidence of delirium, anxiety, apathy, and fatigue. Symptoms of depression were less frequent in the ketamine group three months after surgery (OR [95% CI] 0.34 [0.13-0.86]).

CONCLUSIONS

A single preoperative bolus of intravenous ketamine does not prevent the occurrence of dNR or POND in elderly patients scheduled for major orthopedic surgery. (Clinicaltrials.gov NCT02892916).

Electrophysiological activity pattern of mouse hippocampal CA1 and dentate gyrus under isoflurane anesthesia

General anesthesia can impact a patient's memory and cognition by influencing hippocampal function. The CA1 and dentate gyrus (DG), serving as the primary efferent and gateway of the hippocampal trisynaptic circuit facilitating cognitive learning and memory functions, exhibit significant differences in cellular composition, molecular makeup, and responses to various stimuli. However, the effects of isoflurane-induced general anesthesia on CA1 and DG neuronal activity in mice are not well understood. In this study, utilizing electrophysiological recordings, we examined neuronal population dynamics and single-unit activity (SUA) of CA1 and DG in freely behaving mice during natural sleep and general anesthesia. Our findings reveal that isoflurane anesthesia shifts local field potential (LFP) to delta frequency and reduces the firing rate of SUA in both CA1 and DG, compared to wakefulness. Additionally, the firing rates of DG neurons are significantly lower than CA1 neurons during isoflurane anesthesia, and the recovery of theta power is slower in DG than in CA1 during the transition from anesthesia to wakefulness, indicating a stronger and more prolonged impact of isoflurane anesthesia on DG. This work presents a suitable approach for studying brain activities during general anesthesia and provides evidence for distinct effects of isoflurane anesthesia on hippocampal subregions.

Mendelian randomization of stroke risk after total hip and knee replacements

Objective

Previous epidemiological studies have indicated an increased risk of neurovascular diseases in patients following total hip and knee replacements. However, definitive conclusions regarding the increased risk of stroke post-replacement remain elusive. Therefore, we conducted a two-sample Mendelian randomization study to investigate the causal relationship between total hip and knee replacements and stroke.

Methods

We utilized summary data from publicly available genome-wide association studies (GWAS). Data concerning total hip replacements (THR, N = 319,037) and total knee replacements (TKR, N = 252,041) were sourced from the Genetics of Osteoarthritis (GO) Consortium. Stroke-related data were obtained from the International Stroke Genetics Consortium, encompassing any stroke (AS), any ischemic stroke (AIS), large vessel ischemic stroke (LV-IS), cardioembolic ischemic stroke (CE-IS), and small vessel ischemic stroke (SV-IS). Our primary causal inference method was the inverse variance weighted (IVW) approach, supplemented by weighted median and MR-Egger regression as secondary inference methods. We utilized the MR-PRESSO global test for outlier detection, Cochran's Q statistic to assess heterogeneity, and assessed the multiplicity and stability of our findings using p-values from MR-PRESSO and MR-Egger regressions, and the leave-one-out method, respectively.

Results

We identified significant genetic associations between THR and both AS (IVW p = 0.0001, OR = 1.08, 95% CI = 1.04-1.12) and AIS (IVW p = 0.0016, OR = 1.07, 95% CI = 1.03-1.12). Significant associations were also observed between TKR and AS (IVW p = 0.0002, OR = 1.08, 95% CI = 1.04-1.12), as well as AIS (IVW p = 0.0005, OR = 1.15, 95% CI = 1.06-1.24).

Conclusion

Our findings genetically support an increased risk of stroke following total hip and knee replacements. However, further studies are necessary to elucidate the specific mechanisms underlying stroke episodes post-replacement.

Nutritional Status and Post-Cardiac Surgery Outcomes: An Updated Review with Emphasis on Cognitive Function

Background/Objectives: Nutritional status significantly influences cardiac surgery outcomes, with malnutrition contributing to poorer results and increased complications. This study addresses the critical gap in understanding by exploring the relationship between pre-operative nutritional status and post-operative cognitive dysfunction (POCD) in adult cardiac patients. Methods: A comprehensive search across key databases investigates the prevalence of malnutrition in pre-operative cardiac surgery patients, its effects, and its association with POCD. Factors exacerbating malnutrition, such as chronic illnesses and reduced functionality, are considered. The study also examines the incidence of POCD, its primary association with CABG procedures, and the impact of malnutrition on complications like inflammation, pulmonary and cardiac failure, and renal injury. Discussions: Findings reveal that 46.4% of pre-operative cardiac surgery patients experience malnutrition, linked to chronic illnesses and reduced functionality. Malnutrition significantly contributes to inflammation and complications, including POCD, with an incidence ranging from 15 to 50%. CABG procedures are particularly associated with POCD, and malnutrition prolongs intensive care stays while increasing vulnerability to surgical stress. Conclusions: The review underscores the crucial role of nutrition in recovery and advocates for a universally recognized nutrition assessment tool tailored to diverse cardiac surgery patients. Emphasizing pre-operative enhanced nutrition as a potential strategy to mitigate inflammation and improve cognitive function, the review highlights the need for integrating nutrition screening into clinical practice to optimize outcomes for high-risk cardiac surgery patients. However, to date, most data came from observational studies; hence, there is a need for future interventional studies to test the hypothesis that pre-operative enhanced nutrition can mitigate inflammation and improve cognitive function in this patient population.

Cognitive Impairment Induced by Gestational Diabetes: The Role of Oxidative Stress

BACKGROUND

Cognitive impairment is defined as a neurological condition that alters multiple cerebral functions such as reasoning, memory, concentration, and association, among others. It has found to be widely correlated with several factors such as oxidative stress. The latter could be induced by numerous pathological conditions characterized by increased levels of free radicals and decreased levels of antioxidants. Pregnancy is a period when women undergo a physiological state of oxidative stress due to hormonal changes and increased oxygen requirements to maintain pregnancy. However, when oxidative stress exceeds antioxidant capacity, this leads to cellular damage that promotes a diabetogenic state. Recent studies suggest a possible association between gestational diabetes and cognitive impairment, but the underlying mechanisms remain unclear.

AIMS

We aim to explore the pathophysiological relationship between cognitive impairment and oxidative stress, focusing on the possible involvement of oxidative stress as the inducing mechanism.

METHODS

We performed a comprehensive literature review through PubMed and Google Scholar. Our keywords were "neuroinflammation", "cognitive impairment", "gestational diabetes", "oxidative stress", "antioxidants", and "free radicals".

RESULTS

From the initial 400 records identified, a total of 78 studies were analyzed and included in our study.

CONCLUSION

Oxidative stress plays a fundamental role in the development of cognitive impairment. Understanding this correlation is essential to the development of targeted medical interventions and, ultimately, promote research and prevention that will benefit the mother-child binomial in the short and long term.

Association of preoperative neutrophil-to-lymphocyte ratio with the risk of postoperative delirium in elderly patients undergoing noncardiac surgery: a systematic review and meta-analysis

To assess the correlation between preoperative neutrophil-to-lymphocyte ratio (NLR) and risk of postoperative delirium (POD) in older patients undergoing noncardiac surgery. PubMed, Web of Science, Embase, and Scopus were systematically retrieved from inception until February 2023. Two authors independently conducted the selection of literature, data extraction and statistical analysis. In this meta-analysis, Review Manager 5.4 was used for statistical analysis, and the mean difference (MD) and 95% confidence intervals (CIs) of preoperative NLR between the POD group and non-POD group were calculated. We utilised the Newcastle-Ottawa Scale (NOS) to evaluate the quality of literature. Further, our meta-analysis used a random-effects model, and publication bias was evaluated by conducting a funnel plot. The correlation between preoperative NLR and POD was the primary outcome, and the secondary outcome was the association of other prognostic factors with the risk of POD. This meta-analysis included seven studies with 2424 patients, of whom 403 were diagnosed with POD with an incidence of 16.63%. Results indicated a positive correlation between preoperative NLR and the risk of POD (MD = 1.06, 95% CI: 0.64-1.49; P < 0.001). Further, our results found that neutrophil counts, advanced age, longer surgery time, diabetes, and elevated C-reactive protein were significantly associated with POD (MD = 0.98, 95% CI: 0.40-1.56; P = 0.001; MD = 4.20, 95% CI: 2.90-5.51; P < 0.001; MD = 0.15, 95% CI: 0.05-0.25; P < 0.01; OR = 1.42, 95% CI: 1.08-1.86; P = 0.01; MD = 1.26, 95% CI: 0.36-2.16; P < 0.01). Other factors including lymphocyte counts, hypertension and male gender were not significantly associated with POD (MD = -0.11, 95% CI: -0.27 to 0.05; P > 0.05; OR = 1.20, 95% CI: 0.91-1.58, P > 0.05; OR = 1.28, 95% CI: 1.00-1.63; P = 0.05). Our meta-analysis indicated a positive correlation between preoperative NLR and the risk of POD in older noncardiac surgery patients.

Insulin attenuates LPS-induced cognitive impairment and ferroptosis through regulation of glucose metabolism in hippocampus

AIMS

Neuroinflammation is a recognized contributor to cognitive disorders like Alzheimer's disease, with ferroptosis emerging as a novel mechanism underlying cognitive dysfunction associated with neuroinflammation. Insulin, pivotal in the central nervous system, holds promise for cognitive function enhancement. This study aimed to establish a cognitive impairment model through intracerebroventricular injection of lipopolysaccharide (LPS) and explore the impact of intracerebroventricular insulin injection on cognitive function in mice.

METHODS

We employed diverse experimental techniques, including animal behavior testing, molecular assays, targeted metabolomics, nuclear medicine, and electron microscopy, to assess neurodegenerative changes, brain insulin resistance (IR), glucose uptake and metabolism, and ferroptosis. The model of cognitive impairment was induced via intracerebroventricular injection of LPS, followed by intracerebroventricular administration of insulin to evaluate its effects.

RESULTS

Insulin treatment effectively mitigated LPS-induced cognitive decline and safeguarded against neuronal degeneration. Furthermore, insulin alleviated LPS-induced insulin resistance, enhanced glucose uptake in the hippocampus, and promoted the Pentose Phosphate Pathway (PPP) and nicotinamide adenine dinucleotide phosphate (NADPH) production. Additionally, insulin activated the glutathione (GSH)-glutathione peroxidase 4 (GPX4) pathway, reducing lipid peroxidation, and mitochondrial damage characteristic of LPS-induced ferroptosis in the hippocampus.

CONCLUSION

Our findings underscore the therapeutic potential of insulin in alleviating LPS-induced cognitive impairment and ferroptosis by modulating glucose metabolism. This study offers a promising avenue for future interventions targeting cognitive decline.