Objective:To evaluate the relationship between preoperative concentrations of soluble triggering receptor expressed on myeloid cells 2 (sTREM2) in cerebrospinal fluid (CSF) and postoperative delirium (POD) in patients undergoing total knee/hip arthroplasty.Methods:Six hundred and twenty-five patients of either sex, aged 50-90 yr, weighing 50-80 kg, with American Society of Anesthesiologists Physical Status classification Ⅰor Ⅱ, with the preoperative Mini-Mental State Examination score > 23, who underwent elective knee/hip arthroplasty under combined spinal-epidural anesthesia at Qingdao Municipal Hospital from January 2022 to December 2023, were selected. The CSF specimens 2 ml were withdrawn from the subarachnoid space after successful subarachnoid puncture for determination of the concentrations of sTREM2, Amyloid beta protein (Aβ 42), total tau protein (T-tau), and phosphorylated tau protein (p-tau) by enzyme-linked immunosorbent assay. POD was assessed using the Confusion Assessment Method. Patients were divided into POD group and non-POD group based on whether POD occurred. Logistic regression was used to identify the risk and protective factors for POD. The performance of CSF sTREM2 concentration combined with CSF biomarker levels in predicting POD was evaluated using the receiver operating characteristic (ROC) curve and clinical decision curve. The mediating effect of CSF biomarker concentrations in the relationship between CSF sTREM2 concentration and POD was analyzed. Results:Five hundred and nineteen patients were finally included, with 112 patients in POD group and 407 patients in non-POD group. The results of logistic regression analysis showed that the elevated preoperative sTREM2 concentration in CSF was the risk factor for POD after adjusting for multiple confounding factors such as age, sex, body mass index, years of education, Mini-Mental State Examination score, history of smoking, history of drinking, hypertension, diabetes mellitus and coronary heart disease. The area under the ROC curve of the preoperative sTREM2 concentration in CSF in predicting POD was 0.716, and the area under the ROC curve of the preoperative sTREM2 concentration in CSF combined with CSF biomarkers in predicting POD was 0.796. This model had high clinical application value and predictive efficacy. The relationship between the preoperative sTREM2 concentration in CSF and POD was partially mediated by the CSF p-tau concentration (proportion of mediated effect 24.67%) and t-tau protein concentration (proportion of mediated effect 17.33%).Conclusions:The elevated preoperative concentration of sTREM2 in CSF is a risk factor for POD in patients undergoing total knee/hip arthroplasty, and concentrations of t-tau and p-tau in CSF play a mediating role in the relationship between the preoperative CSF sTREM2 concentration and POD.

Objective:To evaluate the association between postoperative delirium (POD) and preoperative frailty in elderly patients undergoing knee or hip arthroplasty.Methods:This nested case-control study utilized medical records from elderly patients who underwent knee or hip arthroplasty under combined spinal-epidural anesthesia at Qingdao Municipal Hospital between September 2021 and May 2023. Participants were divided into 2 groups based on clinically diagnosed POD: POD group ( n=53) and non-POD group ( n=256). Univariate analysis was conducted on suspected influencing factors, and logistic regression analysis was utilized to identify the risk factors for POD. Receiver operating characteristic and clinical decision curves were plotted to evaluate the predictive performance of these risk factors for POD. Mediation analysis was performed, and a clinically applicable nomogram was constructed to achieve visual prediction of outcomes. Results:There were statistically significant differences in age, preoperative frailty, body mass index, American Society of Anesthesiologists Physical Status classification, Memorial Delirium Assessment Scale scores, and concentrations of Aβ 42, Aβ 40, phosphorylated tau protein (p-tau protein) and tau protein, Aβ 42/tau ratio and Aβ 42/p-tau ratio in cerebrospinal fluid (CSF) between non-POD group and POD group ( P<0.05). Preoperative frailty was a risk factor for POD ( P<0.05). Mediation analysis revealed that the association between preoperative frailty and POD was mediated by CSF tau protein concentrations. The area under the receiver operating characteristic curve of preoperative frailty and CSF biomarker concentrations in predicting POD was 0.974 ( P<0.05). The clinical decision curve demonstrated that the model combining the preoperative frailty and CSF biomarker concentrations predicted a higher net benefit ( P<0.05). The clinical decision curve showed that the model combining preoperative frailty and CSF biomarker concentrations predicted a higher net benefit. Conclusions:Preoperative frailty is a risk factor for POD in elderly patients undergoing knee or hip arthroplasty, and its combination with CSF biomarker concentrations can effectively predict the occurrence of POD. CSF tau concentration mediates the association between preoperative frailty and development of POD.

Objective:To evaluate the association between the preoperative aspartate aminotransferase/alanine aminotransferase (AST/ALT) ratio and postoperative delirium (POD) in patients undergoing total knee/hip arthroplasty.Methods:In this nested case-control study, medical records from patients, aged ≥55 yr, of American Society of Anesthesiologists Physical Status classification Ⅰ or Ⅱ, with Mini-Mental State Examination (MMSE) scale score >24 on preoperative day 1, scheduled for elective total knee/hip arthroplasty under combined spinal-epidural anesthesia at Qingdao Municipal Hospital between November 2021 and December 2023, were collected. POD was assessed using the Confusion Assessment Method. Patients were categorized into POD and non-POD groups based on the occurrence of POD. Logistic regression was employed to identify protective and risk factors for POD. The predictive performance of preoperative AST/ALT ratio alone and its combination with cerebrospinal fluid (CSF) biomarker concentrations for POD was evaluated using receiver operating characteristic curves, and the clinical utility of the prediction models was assessed using decision curve analysis. Mediation analysis was conducted to examine the mediation role of CSF biomarkers in the relationship between the preoperative AST/ALT ratio and POD. Restricted cubic splines were used to assess the nonlinear relationship between the preoperative AST/ALT ratio and POD.Results:A total of 460 patients were finally included, with 49 in POD group and 411 in non-POD group. After adjustment for multiple confounding factors including age, sex, educational level, MMSE score, history of hypertension, history of diabetes, history of smoking and history of alcohol use, multivariable logistic regression identified that the higher preoperative AST/ALT ratio, CSF total tau protein (t-tau) and phosphorylated tau protein (p-tau) concentrations were independent risk factors for POD, whereas lower CSF β-amyloid 42 (Aβ 42) concentration, Aβ 42/t-tau ratio and Aβ 42/p-tau ratio served as protective factors ( P<0.05). The area under the receiver operating characteristic curve of the preoperative AST/ALT ratio combined with CSF biomarkers in predicting POD was 0.939 ( P<0.001), demonstrating high clinical efficacy. After adjusting for age, educational level, sex, MMSE score, history of hypertension, history of diabetes, history of smoking, history of alcohol use and body mass index, restricted cubic splines revealed a nonlinear relationship between preoperative AST/ALT levels and the probability of POD, and the probability of POD increased with rising ratios when the preoperative AST/ALT ratio ranged from 1.09 to 1.40 ( Poverall < 0.05, Pnonlinear <0.05). After stratification by sex, the preoperative AST/ALT ratio demonstrated a linear relationship with the probability of POD ( Poverall <0.05, Pnonlinear>0.05). Mediation analysis indicated that the relationship between the preoperative AST/ALT ratio and POD was partially mediated by CSF p-tau concentration (proportion mediated 18.1%), CSF t-tau concentration (proportion mediated 12.0%), and the Aβ 42/t-tau ratio (proportion mediated 15.4%). Conclusions:A higher preoperative AST/ALT ratio is an independent risk factor for POD in total knee/hip arthroplasty patients. The concentrations of CSF t-tau and p-tau and Aβ 42/t-tau ratio have a mediating role in the relationship between the preoperative AST/ALT ratio and POD.

Objective:To evaluate the association between preoperative cardiometabolic multimorbidity (CMM) and postoperative delirium (POD) in elderly patients undergoing knee or hip replacement.Methods:Based on a perioperative neurocognitive dysfunction and biomarker lifestyle cohort, a nested case-control study was conducted using medical records of patients scheduled for elective knee or hip joint replacement at Qingdao Municipal Hospital from January 2022 to November 2023. Patients were divided into POD group ( n=124) and non-POD group ( n=414) based on whether POD occurred. The influencing factors were collected, and intergroup differences were analyzed. Logistic regression was used to identify the risk factors for POD, and sensitivity analysis was conducted to assess the stability of the regression model. A mediation model was employed to examine whether cerebrospinal fluid (CSF) biomarkers mediated the association between CMM and POD. Results:There were statistically significant differences in the rate of CMM, age, years of education, rate of hypertension, rate of diabetes mellitus, rate of coronary heart diseases, rate of stroke, Aβ 42 concentration, t-tau concentration, p-tau concentration, Aβ 42/t-tau ratio, and Aβ 42/p-tau ratio in CSF between POD group and non-POD group ( P<0.05). The results of logistic regression analysis showed that preoperative CMM was a risk factor for POD ( P<0.05). Mediation analysis revealed that the relationship between CMM and POD was partly mediated by Aβ 42 concentrations in CSF. Conclusions:Preoperative CMM is a risk factor for POD in elderly patients undergoing knee or hip replacement, and the CSF Aβ 42 concentration may play a partly mediating role in the association between preoperative CMM and POD.

Objective:To evaluate the relationship between preoperative concentrations of soluble triggering receptor expressed on myeloid cells 2 (sTREM2) in cerebrospinal fluid (CSF) and postoperative delirium (POD) in patients undergoing total knee/hip arthroplasty.Methods:Six hundred and twenty-five patients of either sex, aged 50-90 yr, weighing 50-80 kg, with American Society of Anesthesiologists Physical Status classification Ⅰor Ⅱ, with the preoperative Mini-Mental State Examination score > 23, who underwent elective knee/hip arthroplasty under combined spinal-epidural anesthesia at Qingdao Municipal Hospital from January 2022 to December 2023, were selected. The CSF specimens 2 ml were withdrawn from the subarachnoid space after successful subarachnoid puncture for determination of the concentrations of sTREM2, Amyloid beta protein (Aβ 42), total tau protein (T-tau), and phosphorylated tau protein (p-tau) by enzyme-linked immunosorbent assay. POD was assessed using the Confusion Assessment Method. Patients were divided into POD group and non-POD group based on whether POD occurred. Logistic regression was used to identify the risk and protective factors for POD. The performance of CSF sTREM2 concentration combined with CSF biomarker levels in predicting POD was evaluated using the receiver operating characteristic (ROC) curve and clinical decision curve. The mediating effect of CSF biomarker concentrations in the relationship between CSF sTREM2 concentration and POD was analyzed. Results:Five hundred and nineteen patients were finally included, with 112 patients in POD group and 407 patients in non-POD group. The results of logistic regression analysis showed that the elevated preoperative sTREM2 concentration in CSF was the risk factor for POD after adjusting for multiple confounding factors such as age, sex, body mass index, years of education, Mini-Mental State Examination score, history of smoking, history of drinking, hypertension, diabetes mellitus and coronary heart disease. The area under the ROC curve of the preoperative sTREM2 concentration in CSF in predicting POD was 0.716, and the area under the ROC curve of the preoperative sTREM2 concentration in CSF combined with CSF biomarkers in predicting POD was 0.796. This model had high clinical application value and predictive efficacy. The relationship between the preoperative sTREM2 concentration in CSF and POD was partially mediated by the CSF p-tau concentration (proportion of mediated effect 24.67%) and t-tau protein concentration (proportion of mediated effect 17.33%).Conclusions:The elevated preoperative concentration of sTREM2 in CSF is a risk factor for POD in patients undergoing total knee/hip arthroplasty, and concentrations of t-tau and p-tau in CSF play a mediating role in the relationship between the preoperative CSF sTREM2 concentration and POD.

Objective:To evaluate the association between postoperative delirium (POD) and preoperative frailty in elderly patients undergoing knee or hip arthroplasty.Methods:This nested case-control study utilized medical records from elderly patients who underwent knee or hip arthroplasty under combined spinal-epidural anesthesia at Qingdao Municipal Hospital between September 2021 and May 2023. Participants were divided into 2 groups based on clinically diagnosed POD: POD group ( n=53) and non-POD group ( n=256). Univariate analysis was conducted on suspected influencing factors, and logistic regression analysis was utilized to identify the risk factors for POD. Receiver operating characteristic and clinical decision curves were plotted to evaluate the predictive performance of these risk factors for POD. Mediation analysis was performed, and a clinically applicable nomogram was constructed to achieve visual prediction of outcomes. Results:There were statistically significant differences in age, preoperative frailty, body mass index, American Society of Anesthesiologists Physical Status classification, Memorial Delirium Assessment Scale scores, and concentrations of Aβ 42, Aβ 40, phosphorylated tau protein (p-tau protein) and tau protein, Aβ 42/tau ratio and Aβ 42/p-tau ratio in cerebrospinal fluid (CSF) between non-POD group and POD group ( P<0.05). Preoperative frailty was a risk factor for POD ( P<0.05). Mediation analysis revealed that the association between preoperative frailty and POD was mediated by CSF tau protein concentrations. The area under the receiver operating characteristic curve of preoperative frailty and CSF biomarker concentrations in predicting POD was 0.974 ( P<0.05). The clinical decision curve demonstrated that the model combining the preoperative frailty and CSF biomarker concentrations predicted a higher net benefit ( P<0.05). The clinical decision curve showed that the model combining preoperative frailty and CSF biomarker concentrations predicted a higher net benefit. Conclusions:Preoperative frailty is a risk factor for POD in elderly patients undergoing knee or hip arthroplasty, and its combination with CSF biomarker concentrations can effectively predict the occurrence of POD. CSF tau concentration mediates the association between preoperative frailty and development of POD.

Objective:To evaluate the association between the preoperative aspartate aminotransferase/alanine aminotransferase (AST/ALT) ratio and postoperative delirium (POD) in patients undergoing total knee/hip arthroplasty.Methods:In this nested case-control study, medical records from patients, aged ≥55 yr, of American Society of Anesthesiologists Physical Status classification Ⅰ or Ⅱ, with Mini-Mental State Examination (MMSE) scale score >24 on preoperative day 1, scheduled for elective total knee/hip arthroplasty under combined spinal-epidural anesthesia at Qingdao Municipal Hospital between November 2021 and December 2023, were collected. POD was assessed using the Confusion Assessment Method. Patients were categorized into POD and non-POD groups based on the occurrence of POD. Logistic regression was employed to identify protective and risk factors for POD. The predictive performance of preoperative AST/ALT ratio alone and its combination with cerebrospinal fluid (CSF) biomarker concentrations for POD was evaluated using receiver operating characteristic curves, and the clinical utility of the prediction models was assessed using decision curve analysis. Mediation analysis was conducted to examine the mediation role of CSF biomarkers in the relationship between the preoperative AST/ALT ratio and POD. Restricted cubic splines were used to assess the nonlinear relationship between the preoperative AST/ALT ratio and POD.Results:A total of 460 patients were finally included, with 49 in POD group and 411 in non-POD group. After adjustment for multiple confounding factors including age, sex, educational level, MMSE score, history of hypertension, history of diabetes, history of smoking and history of alcohol use, multivariable logistic regression identified that the higher preoperative AST/ALT ratio, CSF total tau protein (t-tau) and phosphorylated tau protein (p-tau) concentrations were independent risk factors for POD, whereas lower CSF β-amyloid 42 (Aβ 42) concentration, Aβ 42/t-tau ratio and Aβ 42/p-tau ratio served as protective factors ( P<0.05). The area under the receiver operating characteristic curve of the preoperative AST/ALT ratio combined with CSF biomarkers in predicting POD was 0.939 ( P<0.001), demonstrating high clinical efficacy. After adjusting for age, educational level, sex, MMSE score, history of hypertension, history of diabetes, history of smoking, history of alcohol use and body mass index, restricted cubic splines revealed a nonlinear relationship between preoperative AST/ALT levels and the probability of POD, and the probability of POD increased with rising ratios when the preoperative AST/ALT ratio ranged from 1.09 to 1.40 ( Poverall < 0.05, Pnonlinear <0.05). After stratification by sex, the preoperative AST/ALT ratio demonstrated a linear relationship with the probability of POD ( Poverall <0.05, Pnonlinear>0.05). Mediation analysis indicated that the relationship between the preoperative AST/ALT ratio and POD was partially mediated by CSF p-tau concentration (proportion mediated 18.1%), CSF t-tau concentration (proportion mediated 12.0%), and the Aβ 42/t-tau ratio (proportion mediated 15.4%). Conclusions:A higher preoperative AST/ALT ratio is an independent risk factor for POD in total knee/hip arthroplasty patients. The concentrations of CSF t-tau and p-tau and Aβ 42/t-tau ratio have a mediating role in the relationship between the preoperative AST/ALT ratio and POD.

Objective:To evaluate the association between preoperative cardiometabolic multimorbidity (CMM) and postoperative delirium (POD) in elderly patients undergoing knee or hip replacement.Methods:Based on a perioperative neurocognitive dysfunction and biomarker lifestyle cohort, a nested case-control study was conducted using medical records of patients scheduled for elective knee or hip joint replacement at Qingdao Municipal Hospital from January 2022 to November 2023. Patients were divided into POD group ( n=124) and non-POD group ( n=414) based on whether POD occurred. The influencing factors were collected, and intergroup differences were analyzed. Logistic regression was used to identify the risk factors for POD, and sensitivity analysis was conducted to assess the stability of the regression model. A mediation model was employed to examine whether cerebrospinal fluid (CSF) biomarkers mediated the association between CMM and POD. Results:There were statistically significant differences in the rate of CMM, age, years of education, rate of hypertension, rate of diabetes mellitus, rate of coronary heart diseases, rate of stroke, Aβ 42 concentration, t-tau concentration, p-tau concentration, Aβ 42/t-tau ratio, and Aβ 42/p-tau ratio in CSF between POD group and non-POD group ( P<0.05). The results of logistic regression analysis showed that preoperative CMM was a risk factor for POD ( P<0.05). Mediation analysis revealed that the relationship between CMM and POD was partly mediated by Aβ 42 concentrations in CSF. Conclusions:Preoperative CMM is a risk factor for POD in elderly patients undergoing knee or hip replacement, and the CSF Aβ 42 concentration may play a partly mediating role in the association between preoperative CMM and POD.

Grooming,as an evolutionarily conserved repetitive behavior,is common in various animals,including humans,and serves essential functions including,but not limited to,hygiene maintenance,thermoregulation,de-arousal,stress reduction,and social behaviors.In rodents,grooming involves a patterned and sequenced structure,known as the syntactic chain with four phases that comprise repeated stereotyped movements happening in a cephalocaudal progression style,beginning from the nose to the face,to the head,and finally ending with body licking.The context-dependent occurrence of grooming behavior indicates its adaptive significance.This review briefly summarizes the neural substrates responsible for rodent grooming behavior and explores its relevance in rodent models of neuropsychiatric disorders and neurodegenerative diseases with aberrant grooming phenotypes.We further emphasize the utility of rodent grooming as a reliable measure of repetitive behavior in neuropsychiatric models,holding promise for translational psychiatry.Herein,we mainly focus on rodent self-grooming.Allogrooming(grooming being applied on one animal by its conspecifics via licking or carefully nibbling)and heterogrooming(a form of grooming behavior directing towards another animal,which occurs in other contexts,such as maternal,sexual,aggressive,or social behaviors)are not covered due to space constraints.

Objective To explore the possible causes of CAST/EiJ mouse susceptibility to multiple pathogens,the immune cell phenotypes in the peripheral blood and spleen of CAST/EiJ mice were analyzed to clarify their composition.Methods Classical dendritic cells(cDCs),natural killer(NK)cells,B lymphocytes,T lymphocytes,and their subsets in the peripheral blood and spleen of CAST/EiJ mice and C57BL/6J mice were detected by flow cytometry using the cell surface markers CD3,CD4,CD8,CD11b,CD11c,CD19,CD27,CD49b,and TCRβ.Results There was no significant difference in the proportion of cDCs between CAST/EiJ and C57BL/6J mice,but the cDC1 cell subset population was smaller in CAST/EiJ.The proportions of NK cells(mainly mature NK cell subsets)and T lymphocytes(mainly CD8+T cells)were both lower in CAST/EiJ mice than C57BL/6J mice,while the proportion of B cells was higher in CAST/EiJ mice than C57BL/6J mice.Conclusions The proportions of NK and T lymphocytes in CAST/EiJ mice were lower than those in C57BL/6J mice.