Postoperative cognitive dysfunction: current developments in mechanism and prevention

The effects of dexmedetomidine on postoperative cognitive dysfunction in rats with bone fractures undergoing open reduction

OBJECTIVE

To investigate the effects of dexmedetomidine on the cognitive dysfunction of aged rats after open tibia fracture surgery and the expression of inflammatory cytokines in the hippocampus.

METHODS

A total of 45 aged healthy male Sprague Dawley rats were divided into control group, sham group, and dexmedetomidine group. The open tibia fracture surgery rat model was established, and dexmedetomidine was intraperitoneally injected before operation. The cognitive function of aged rats was examined by Morris Water-Maze Test, open field experiment, and passive avoidance memory test. The expression levels of IL-6, IL-1β, and TNF-α in the hippocampus were examined by enzyme-linked immunosorbent assay (ELISA).

RESULTS

The escape latency over 5 continuous days in the dexmedetomidine group was significantly shorter than that in the control group (all P<0.05). The number of swimming times and the percentage of swimming time in the dexmedetomidine group were significantly higher and longer than those in the control group (all P<0.05). Moreover, rats in the dexmedetomidine group exhibited shorter time of stay at the central square and higher number of standing times in comparison with the control group (all P<0.05). Compared with the control group, dexmedetomidine intraperitoneally injected before surgery significantly inhibited the expression levels of IL-6, IL-1β, and TNF-α in the hippocampus (all P<0.05).

CONCLUSION

Dexmedetomidine could significantly relieve the postoperative cognitive dysfunction in aged rats. The mechanism may be associated with the decreased inflammatory cytokines in the hippocampus.

Hippocampal HDAC6 promotes POCD by regulating NLRP3-induced microglia pyroptosis via HSP90/HSP70 in aged mice

BACKGROUND

Postoperative Cognitive Dysfunction (POCD) has attracted increased attention, but its precise mechanism remains to be explored. This study aimed to figure out whether HDAC6 could regulate NLRP3-induced pyroptosis by modulating the functions of HSP70 and HSP90 in microglia to participate in postoperative cognitive dysfunction in aged mice.

METHODS

Animal models of postoperative cognitive dysfunction in aged mice were established by splenectomy under sevoflurane anesthesia. Morris water maze was used to examine the cognitive function and motor ability. Sixteen-months-old C57BL/6 male mice were randomly divided into six groups: control group (C group), sham surgery group (SA group), splenectomy group (S group), splenectomy + HDAC6 inhibitor ACY-1215 group (ACY group), splenectomy + HDAC6 inhibitor ACY-1215 + HSP70 inhibitor Apoptozole group (AP group), splenectomy + solvent control group (SC group). The serum and hippocampus of mice were taken after mice were executed. The protein levels of HDAC6, HSP90, HSP70, NLRP3, GSDMD-N, cleaved-Caspase-1 (P20), IL-1β were detected by western blotting. Serum IL-1β, IL-6 and S100β were measured using ELISA assay, and cell localization of HDAC6 was detected by immunofluorescence. In vitro experiments, BV2 cells were used to validate whether this mechanism worked in microglia. The protein levels of HDAC6, HSP90, HSP70, NLRP3, GSDMD-N, P20, IL-1β were detected by western blotting and the content of IL-1β in the supernatant was measured using ELISA assay. The degree of acetylation of HSP90, the interaction of HSP70, HSP90 and NLRP3 were analyzed by coimmunoprecipitation assay.

RESULTS

Splenectomy under sevoflurane anesthesia in aged mice could prolong the escape latency, reduce the number of crossing platforms, increase the expression of HDAC6 and activate the NLRP3 inflammasome to induce pyroptosis in hippocampus microglia. Using ACY-1215 could reduce the activation of NLRP3 inflammasome, the pyroptosis of microglia and the degree of spatial memory impairment. Apoptozole could inhibit the binding of HSP70 to NLRP3, reduce the degradation of NLRP3 and reverse the protective effect of HDAC6 inhibitors. The results acquired in vitro experiments closely resembled those in vivo, LPS stimulation led to the pyroptosis of BV2 microglia cells and the release of IL-1β due to the activation of the NLRP3 inflammasome, ACY-1215 showed the anti-inflammatory effect and Apoptozole exerted the opposite effect.

CONCLUSIONS

Our findings suggest that hippocampal HDAC6 promotes POCD by regulating NLRP3-induced microglia pyroptosis via HSP90/HSP70 in aged mice.

Propionic acid ameliorates cognitive function through immunomodulatory effects on Th17 cells in perioperative neurocognitive disorders

Background

Elderly patients undergoing surgery are prone to cognitive decline known as perioperative neurocognitive disorders (PND). Several studies have shown that the microglial activation and the decrease of short-chain fatty acids (SCFAs) in gut induced by surgery may be related to the pathogenesis of PND. The purpose of this study was to determine whether microglia and short-chain fatty acids were involved in cognitive dysfunction in aged rats.

Methods

Male wild-type Wistar rats aged 11-12 months were randomly divided into control group (Ctrl: Veh group), propionic acid group (Ctrl: PA group), exploratory laparotomy group (LP: Veh group) and propionic acid + exploratory laparotomy group (LP: PA group) according to whether exploratory laparotomy (LP) or PA pretreatment for 21 days was performed. The motor ability of the rats was evaluated by open field test on postoperative day 3 (POD3), and then the cognitive function was evaluated by Y-maze test and fear conditioning test. The expression of IL-1β, IL-6, RORγt and IL-17A mRNA in hippocampus was detected by RT-qPCR, the expression of IL-17A and IL-17RA in hippocampus was detected by Western blot, and the activation of microglia was detected by immunofluorescence.

Results

The PND rat model was successfully established by laparotomy. Compared with Ctrl: Veh group, the body weight of LP: Veh group decreased, the percentage of spontaneous alternations in Y maze decreased (P < 0.001), and the percentage of freezing time in contextual fear test decreased (P < 0.001). Surgery triggers neuroinflammation, manifested as the elevated levels of the inflammatory cytokines IL-1β (P < 0.001) and IL-6 (P < 0.001), the increased expression of the transcription factor RORγt (P = 0.0181, POD1; P = 0.0073, POD5)and major inflammatory cytokines IL-17A (P = 0.0215, POD1; P = 0.0071, POD5), and the increased average fluorescence intensity of Iba1 (P < 0.001, POD1; P < 0.001, POD5). After PA preconditioning, the recovery of rats in LP: PA group was faster than that in LP: Veh group as the body weight lost on POD1 (P = 0.0148) was close to the baseline level on POD5 (P = 0.1846), and they performed better in behavioral tests. The levels of IL-1β (P < 0.001) and IL-6 (P = 0.0035) inflammatory factors in hippocampus decreased on POD1 and the average fluorescence intensity of Iba1 decreased (P = 0.0024, POD1; P < 0.001, POD5), representing the neuroinflammation was significantly improved. Besides, the levels of RORγt mRNA (P = 0.0231, POD1; P = 0.0251, POD5) and IL-17A mRNA (P = 0.0208, POD1; P = 0.0071, POD5) in hippocampus as well as the expression of IL-17A (P = 0.0057, POD1; P < 0.001, POD5) and IL-17RA (P = 0.0388) decreased.

Conclusion

PA pretreatment results in reduced postoperative neuroinflammation and improved cognitive function, potentially attributed to the regulatory effects of PA on Th17-mediated immune responses.

Early postoperative neurocognitive complications in elderly patients: comparing those with and without preexisting mild cognitive impairment- a prospective study

BACKGROUND

As societies age, increasing numbers of older adults undergo surgeries with anesthesia. Postoperative delirium (POD) and postoperative cognitive dysfunction (POCD) frequently occur in older surgical patients. Most of these patients already have preoperative mild cognitive impairment (MCI). However, the correlation between MCI and POD remains unclear. This study aimed to determine the incidence of POD in elderly patients with and without preexisting MCI.

METHODS

A prospective study enrolled patients aged 60 years and above scheduled for major surgeries between December 2017 and April 2022. Preoperative MCI was determined by a Montreal Cognitive Assessment (MoCA) score between 18 and 24. POD was diagnosed using criteria from the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5). POCD was characterized by a MoCA score reduction of 2 or more points from the preoperative score. The primary outcome was the incidence of POD within the first 72 h postoperatively. Secondary outcomes encompassed other postoperative complications, including POCD.

RESULTS

The study comprised 223 elderly patients with MCI and 56 without MCI. The incidence of POD was 16.6% in the MCI group and 14.3% in the non-MCI group (P = 0.839). POCD occurred in 24.3% of MCI patients and 50% of non-MCI patients (P = 0.001). There were no significant differences in other postoperative complications between the groups. Postoperatively, the MCI group notably declined in visuospatial, attention, and orientation domains, while the non-MCI group declined in all domains except delayed recall.

CONCLUSIONS

The incidence of POD was similar in the MCI and non-MCI groups. However, the non-MCI group demonstrated a higher incidence of POCD than the MCI group. This was identified by a reduction in postoperative MoCA scores for the visuospatial, naming, attention, language, abstraction, and orientation domains. These findings underscore the importance of postoperative cognitive assessments for both elderly patients with preexisting MCI and those with previously intact cognitive functions.

TRIAL REGISTRATION

This trial was retrospectively registered in the Thai Clinical Trials Registry on 15/01/2019 (registration number: TCTR20190115001).

Evaluation of the effects of total intravenous anesthesia and inhalation anesthesia on postoperative cognitive recovery

OBJECTIVE

To compare the effects of total intravenous anesthesia (TIVA) and inhalation anesthesia (IA) used in lumbar disc herniectomy on postoperative cognitive recovery based on the mini-mental state examination (MMSE) score and neuron-specific enolase (NSE) levels.

MATERIAL AND METHODS

The study sample consisted of 80 patients aged 18-65 years who were scheduled for elective lumbar disc herniectomy. The patients were divided into two groups according to the anesthesia technique applied, such as TIVA or IA. The patients in the TIVA group were administered remifentanil and propofol and those in the IA group were administered sevoflurane for maintenance. The MMSE was applied to the patients before the operation and 1h and 24 h postoperatively. Venous blood samples were obtained for the measurement of NSE before the operation and on the 24 h postoperatively.

RESULTS

The mean preoperative MMSE scores were similar in the two groups. In the TIVA group, the preoperative and postoperative MMSE scores at 1 h were similar but were higher at 24 h postoperatively compared to the previous two scores (p = 0.001 and p < 0.001, respectively). In the IA group, the preoperative and postoperative 24 h MMSE scores were similar but lower at 1h postoperatively than the other two scores (p = 0.006 and p < 0.001, respectively). In the TIVA group, there was a significant decrease in the postoperative serum NSE levels than the preoperative values (p = 0.038).

CONCLUSION

The use of IA may result in higher cognitive dysfunction 1h after the operation compared to TIVA. The effects of both methods on cognitive functions were similar at 24 h postoperatively.

Enhancing recovery in older patients undergoing abdominal surgery: Examining the effect of a preoperative preparation program using a quasi-experimental design

Background

Older adult patients often experience delayed postoperative recovery due to a lack of self-efficacy in engaging in physical activities during early rehabilitation. Concurrently, family caregivers play a crucial role in caring for older adults. However, the extent of family involvement in improving self-efficacy and facilitating recovery following major abdominal surgeries in older adults remains largely unexplored.

Objective

This study aimed to examine the effect of a preoperative preparation program on the recovery of older patients undergoing major abdominal surgeries.

Methods

A quasi-experimental study with a two-group, pretest-posttest design was conducted. The participants included 60 older adult patients undergoing abdominal surgeries at Thammasat University Hospital, Thailand, between September 2019 and March 2020. Participants were selected by purposive sampling with the inclusion criteria and were assigned to the experimental (n = 30) or the control (n = 30) groups using matched pair according to the type of operation. The control group received standard care, while the intervention group underwent a two-week preoperative preparation program developed based on self-efficacy theory and family support. Data were collected using validated tools. Recovery was assessed at one week and two weeks after surgery. Descriptive statistics, as well as dependent and independent t-tests, were used for data analysis.

Results

The results revealed that the intervention group had significantly higher mean recovery scores than the control group at one week (M = 56.93, SD = 16.42; M = 44.60, SD = 16.30, t = -2.92, df = 58, p <0.01) and two weeks after surgery (M = 66.64, SD = 8.63; M = 61.68, SD = 7.86, t = -2.33, df = 58, p <0.05) when comparing between the two groups.

Conclusion

The preoperative preparation program effectively enhanced recovery one week and two weeks after surgery. The study findings can be valuable for nurses in implementing the preoperative preparation program to facilitate recovery among older adult patients undergoing abdominal surgeries.

Obesity and Postoperative Cognitive Dysfunction: A Curious Association

Postoperative cognitive dysfunction (POCD) is a medical condition that impacts cognitive function after surgery, particularly major procedures. Patients with POCD may experience physical symptoms, such as depression, anxiety, and fatigue, severely undermining their quality of life. Research establishes the connection between obesity and cognitive dysfunction since patients diagnosed with obesity are more susceptible to cognitive decline. Although obesity poses a significant risk factor for cognitive impairment, the link between obesity and POCD is still inadequately understood. Therefore, this systematic review explores the correlation between obesity and POCD by detailing potential mechanisms underlying this relationship and identifying areas for further research. Following the guidelines for systematic reviews, we conducted a literature search between August 2022 and April 2023, which identified studies with a substantial number of patients with POCD after major surgeries, including coronary artery bypass grafting, gastrointestinal procedures, cholecystectomy, and carotid endarterectomy. Our findings also demonstrated that a significant percentage of these had obesity, which was statistically significant as a risk factor for cognitive decline. Pathological processes, such as changes in vascular endothelium integrity, systemic inflammation induced by obesity, and apolipoprotein E-epsilon-4 expression, have been identified to contribute to POCD after surgery. Despite the promising results, there remains a gap in the literature. Thus, it is crucial to investigate the relationship between obesity and POCD further, uncover more potential underlying pathophysiological processes, and identify therapeutic targets. These measures would enable healthcare practitioners to prevent or reduce cognitive dysfunction associated with obesity in surgical patients.

Sevoflurane and desflurane effects on early cognitive function after low-risk surgery: A randomized clinical trial

BACKGROUND AND OBJECTIVES

Deleterious effects on short-term and long-term quality of life have been associated with the development of postoperative cognitive dysfunction (POCD) after general anesthesia. Yet, the progress in the field is still required. Most of the studies investigate POCD after major surgery, so scarce evidence exists about the incidence and effect different anesthetics have on POCD development after minor procedures. In this study, we compared early postoperative cognitive function of the sevoflurane and desflurane patients who experienced a low-risk surgery of thyroid gland.

MATERIALS AND METHODS

Eighty-two patients, 40 years and over, with no previous severe cognitive, neurological, or psychiatric disorders, appointed for thyroid surgery under general anesthesia, were included in the study. In a random manner, the patients were allocated to either sevoflurane or desflurane study arms. Cognitive tests assessing memory, attention, and logical reasoning were performed twice: the day before the surgery and 24 h after the procedure. Primary outcome, magnitude of change in cognitive testing, results from baseline. POCD was diagnosed if postoperative score decreased by at least 20%.

RESULTS

Median change from baseline cognitive results did not differ between the sevoflurane and desflurane groups (-2.63%, IQR 19.3 vs. 1.13%, IQR 11.0; p = .222). POCD was detected in one patient (1.22%) of the sevoflurane group. Age, duration of anesthesia, postoperative pain, or patient satisfaction did not correlate with test scores. Intraoperative temperature negatively correlated with total postoperative score (r = -0.35, p = .007).

CONCLUSIONS

Both volatile agents proved to be equivalent in terms of the early cognitive functioning after low-risk thyroid surgery. Intraoperative body temperature may influence postoperative cognitive performance.

The Management of Postoperative Cognitive Dysfunction in Cirrhotic Patients: An Overview of the Literature

Background and objectives: Postoperative cognitive dysfunction (POCD) represents a decreased cognitive performance in patients undergoing general anesthesia for major surgery. Since liver cirrhosis is associated with high mortality and morbidity rates, cirrhotic patients also assemble many risk factors for POCD. Therefore, preserving cognition after major surgery is a priority, especially in this group of patients. The purpose of this review is to summarize the current knowledge regarding the effectiveness of perioperative therapeutic strategies in terms of cognitive dysfunction reduction. Data Collection: Using medical search engines such as PubMed, Google Scholar, and Cochrane library, we analyzed articles on topics such as: POCD, perioperative management in patients with cirrhosis, hepatic encephalopathy, general anesthesia in patients with liver cirrhosis, depth of anesthesia, virtual reality in perioperative settings. We included 115 relevant original articles, reviews and meta-analyses, and other article types such as case reports, guidelines, editorials, and medical books. Results: According to the reviewed literature, the predictive capacity of the common clinical tools used to quantify cognitive dysfunction in cirrhotic settings is reduced in perioperative settings; however, novel neuropsychological tools could manage to better identify the subclinical forms of perioperative cognitive impairments in cirrhotic patients. Moreover, patients with preoperative hepatic encephalopathy could benefit from specific preventive strategies aimed to reduce the risk of further neurocognitive deterioration. Intraoperatively, the adequate monitoring of the anesthesia depth, appropriate anesthetics use, and an opioid-sparing technique have shown favorable results in terms of POCD. Early recovery after surgery (ERAS) protocols should be implemented in the postoperative setting. Other pharmacological strategies provided conflicting results in reducing POCD in cirrhotic patients. Conclusions: The perioperative management of the cognitive function of cirrhotic patients is challenging for anesthesia providers, with specific and targeted therapies for POCD still sparse. Therefore, the implementation of preventive strategies appears to remain the optimal attitude. Further research is needed for a better understanding of POCD, especially in cirrhotic patients.

Feasibility study of use of desflurane combined with dexmedetomidine in inhibiting postoperative neurocognitive disorders in elderly patients under general anesthesia: A perspective study

This study aimed to explore whether the combined application of desflurane and dexmedetomidine (Dex) reduces the occurrence of postoperative neurocognitive disorders (PND) in patients. We selected patients in our hospital who underwent surgery under general anesthesia, and divided them into two groups: Dex and desflurane (Dex + Des) and desflurane (Des) groups. The data of patients were collected and the Mini-Mental State Examination (MMSE) score was used to assess cognitive status. The blood cell counts were determined preoperatively and on postoperative days 1, 3, and 6, and the percentage of neutrophils and lymphocytes were also recorded. The statistical methods used were the independent-samples t-test and the χ 2 test. Pearson's correlation was used to analyze the correlation between PND and inflammation. The incidence of PND in the Dex + Des group was lower than that in the Des group. The postoperative MMSE scores in the Dex + Des group were higher than those in the Des group (p = 0.032). The percentage of neutrophils in the Dex + Des group was significantly lower than that in the Des group on the first and third days after surgery (p = 0.007; p = 0.028). The MMSE scores on the first day after surgery were negatively correlated with the multiple changes in white blood counts and the percentage of neutrophils (r = -0.3038 and -0.3330). Dex combined with Des reduced the incidence of PND and reduced the postoperative inflammatory cell counts.

The Crosstalk between the Blood–Brain Barrier Dysfunction and Neuroinflammation after General Anaesthesia

As we know, with continuous medical progress, the treatment of many diseases can be conducted via surgery, which often relies on general anaesthesia for its satisfactory performance. With the widespread use of general anaesthetics, people are beginning to question the safety of general anaesthesia and there is a growing interest in central nervous system (CNS) complications associated with anaesthetics. Recently, abundant evidence has suggested that both blood–brain barrier (BBB) dysfunction and neuroinflammation play roles in the development of CNS complications after anaesthesia. Whether there is a crosstalk between BBB dysfunction and neuroinflammation after general anaesthesia, and whether this possible crosstalk could be a therapeutic target for CNS complications after general anaesthesia needs to be clarified by further studies.

Which Predictor, SctO2 or SstO2, Is more Sensitive for Postoperative Cognitive Dysfunction in Spine Surgery: A Prospective Observational Study?

OBJECTIVE

Patients undergoing spinal surgery in the prone position may experience venous stasis, often resulting in edema in dependent areas of the body, including the head, and increased postoperative cognitive dysfunction (POCD). Not only does POCD present challenges for post-operative care and recovery, it can also cause permanent damage to the patient's brain and increase mortality and social costs. We aimed to clarify the incidence of POCD in patients with hypertension after prone spine surgery and to further determine the association between intraoperative somatic tissue oxygen saturation (SstO2)/cerebral tissue oxygen saturation (SctO2) and POCD.

METHODS

Patients with hypertension scheduled for open prone spine surgery from January 2020 to April 2021 were included in this single-center, prospective, observational study. SctO2 and SstO2 were monitored by near-infrared spectroscopy continuously throughout the surgery. The primary outcome was POCD assessed using the Mini-Mental Status Examination (MMSE). The association of SstO2 and SctO2 with POCD was evaluated with unadjusted analyses and multivariable logistic regression.

RESULTS

One hundred and one of 112 identified patients were included, 28 (27.8%) of whom developed POCD. None of the investigated SctO2 indices were predictive of POCD. However, the patients with POCD had greater decreases in intraoperative absolute SstO2 and relative SstO2 than the patients without POCD (P = 0.037, P = 0.036). Moreover, three SstO2 indices were associated with POCD, including a greater absolute SstO2 decrease (P = 0.021), a greater relative SstO2 decrease (P = 0.032), and a drop below 90% of the baseline SstO2 (P = 0.002), independent of ASA III status, preoperative platelets and postoperative sepsis. In addition, there was no correlation between intraoperative SctO2 and intraoperative SstO2 or between their respective absolute declines.

CONCLUSION

Twenty-eight (27.7%) of 101 patients developed POCD in patients with hypertension undergoing prone spine surgery, and intraoperative SstO2 is associated with POCD, whereas SctO2 shows no association with POCD. This study may initially provide a valuable new approach to the prevention of POCD in this population.

Effects of Dexmedetomidine Anesthesia on Early Postoperative Cognitive Dysfunction in Elderly Patients

The stimulation of tracheal extraction and anesthesia may lead to early postoperative cognitive dysfunction (POCD) in elderly patients, especially within 72 h after surgery, due to the insufficient compensatory and regulatory effects of their cardiovascular system. This study was performed to demonstrate the effects of additional dexmedetomidine (DEX) administration on alleviating early POCD (72 h post intubation) and inflammation in elderly patients who underwent intubation. A parallel-randomized trial was performed in this study. A total of 100 patients aged 60-85 years were randomly divided into two groups (DEX, n = 50; control, n = 50). They received traditional anesthesia and additional DEX medications. Mini-mental state examination (MMSE) and Montreal cognitive assessment (MoCA) were used to assess the cognitive dysfunction of patients. The enzyme-linked immunosorbent assay (ELISA) was used to detect the stress and inflammatory response of the two groups of patients. Administration of DEX significantly improved the MMSE and MoCA scores 24 and 72 h post operation. The S100β and neuron-specific enolase (NSE) levels in serum were downregulated by DEX 6 and 24 h post operation. The norepinephrine and cortisol levels in serum were downregulated by DEX 15 and 30 min post operation. The interleukin-6 (IL-6) and tumor necrosis factor α (TNF-α) levels in serum were also downregulated by DEX 15 and 30 min post operation. DEX alleviated POCD and inflammation in elderly patients who underwent intubation.

Dexmedetomidine improved one-lung ventilation-induced cognitive dysfunction in rats

BACKGROUND

One-lung ventilation (OLV) is widely used in thoracic surgery. However, OLV may also increase CERO₂ and aggravate delayed cognitive recovery. Here, we aimed to investigate the effect of dexmedetomidine (DEX) on cognitive function in rats undergoing OLV.

METHODS

Sprague-Dawley rats were randomly divided into two-lung ventilation (TLV) group, OLV group and OLV treated with DEX group. Group DEX received 25 μg/kg DEX i.p. 30 min before induction. After mechanical ventilation (MV), Morris water maze (MWM) test was carried out to examine spatial memory function. Western blotting was used to detect pERK1/2, pCREB, Bcl-2 and BAX in hippocampal tissues. Transmission electron microscopy (TEM) was used to observe the hippocampal CA1 region.

RESULTS

Post-MV, compared with group OLV, group DEX showed increases in percentage of target quadrant time (P < 0.05), platform crossings (P < 0.05), a reduction in CERO₂ (P < 0.05), and pERK1/2, pCREB, and Bcl-2 significantly increased (P < 0.01 or P < 0.05), while BAX significantly decreased (P < 0.01), besides, a less damaged synaptic structure was observed in group DEX.

CONCLUSIONS

DEX improved post-MV cognitive function in rats undergoing OLV, reduced cerebral oxygen consumption, protected synaptic structure and upregulated ERK1/2-CREB anti-apoptotic signaling pathway in hippocampal CA1 region.

ABCA7 rs3764650 Polymorphism is Associated with Delayed Neurocognitive Recovery

Background

Several studies have shown that ATP-binding cassette transporter A7 (ABCA7) gene variation is associated with cognitive impairment. This study was aimed to investigate the relationship between ABCA7 rs3764650 polymorphism and perioperative neurocognitive disorder (pNCD).

Methods

A total of 132 elderly patients aged 65 and over who underwent elective non-cardiac surgery were enrolled in the study, while 28 healthy volunteers matching age and sex were recruited as the control group. A battery of neuropsychological tests was conducted 1 day before, 7 days, and 3 months after surgeries. Delayed neurocognitive recovery (dNCR) and postoperative mild or major neurocognitive disorder (POCD) were determined using the Z value method. The venous blood sample of the surgical patients was taken before the operation. Genotyping of rs3764650 was performed using polymerase chain reaction amplification and restriction fragment length polymorphism analysis.

Results

The incidences of dNCR and POCD were 29.7% and 16.8% at 7 days and 3 months after surgery, respectively. The G allele frequency and GG frequency of dNCR patients were significantly higher than that of non-dNCR patients (43.3% vs 28.2%, P=0.035; 23.3% vs 4.2%, P=0.013, respectively) at 7 days following surgery. No significant differences in ABCA7 alleles between POCD and non-POCD patients were observed 3 months postoperatively.

Conclusion

ABCA7 rs3764650 gene polymorphism is associated with dNCR and GG genotype might be a predisposing factor for postoperative cognitive impairment in Chinese Han elderly populations.

Effects of anesthetics on expression of dopamine and acetylcholine receptors in the rat brain in vivo

Dopamine D₂ and acetylcholine M₁ receptors might be related to post-operative cognitive dysfunction. The aim of the present study is to investigate whether several anesthetics which are used for general anesthesia and/or sedation, affect expression of dopamine D₂ and acetylcholine M₁ receptors in the rat brain. Thirty-six male rats aged 5-9 weeks old were divided into six groups (n = 6 in each group); five groups for anesthetics and one for control. The five groups were anesthetized with either dexmedetomidine 0.4 µg/kg/min, propofol 50 mg/kg/h, midazolam 25 mg/kg/h, sevoflurane 3.3%, or nitrous oxide 75% for 4 h. Then, the rats were decapitated, and the cerebral cortex, hippocampus, corpus striatum, brain stem, and cerebellum were collected from all rats. Then, real-time polymerase chain reaction was performed to examine the expression of Drd2 (cord dopamine D₂ receptor) and Chrm1 (cord acetylcholine M₁ receptor). There were no significant differences among the groups regarding Drd2 and Chrm1 mRNA expression of each region of the brain. Postsynaptic changes of dopamine D₂ and acetylcholine M₁ receptors due to administration of dexmedetomidine, propofol, midazolam, sevoflurane, and nitrous oxide are unlikely to occur at the doses of each anesthetic used in the present study.

Ginsenosides in central nervous system diseases: Pharmacological actions, mechanisms, and therapeutics

The nervous system is one of the most complex physiological systems, and central nervous system diseases (CNSDs) are serious diseases that affect human health. Ginseng (Panax L.), the root of Panax species, are famous Chinese herbs that have been used for various diseases in China, Japan, and Korea since ancient times, and remain a popular natural medicine used worldwide in modern times. Ginsenosides are the main active components of ginseng, and increasing evidence has demonstrated that ginsenosides can prevent CNSDs, including neurodegenerative diseases, memory and cognitive impairment, cerebral ischemia injury, depression, brain glioma, multiple sclerosis, which has been confirmed in numerous studies. Therefore, this review summarizes the potential pathways by which ginsenosides affect the pathogenesis of CNSDs mainly including antioxidant effects, anti-inflammatory effects, anti-apoptotic effects, and nerve protection, which provides novel ideas for the treatment of CNSDs.

Effects of Omega-3 Polyunsaturated Fatty Acids on Cognitive Function after Splenectomy in Rats

Background

Postoperative cognitive dysfunction (POCD) is a common complication after abdominal surgery. Several studies have reported that POCD is related to neuroinflammation caused by surgery. Omega-3 polyunsaturated fatty acids (PUFAs) can effectively inhibit the systematic inflammatory response. So, we use fish oil to study the effect of fish oil on inflammation, immunity, and cognitive behavior after splenectomy in rats.

Methods

60 SD (Sprague-Dawley) rats were randomly divided into control group (group C, n = 20), surgery group (group S, n = 20), and omega-3 (fish oil) intervention group (group F, n = 20). Omega-3 PUFA was injected intraperitoneally from 3 days before operation to 7 days after operation in group F, and normal saline was injected simultaneously in group S. Rats in group S and group F received splenectomy under general anesthesia. Morris water maze behavioral evaluation was performed on the first, third, fifth, and seventh day after operation. The levels of IL-1β (interleukin-1β), IL-6 (interleukin-6), TNF-α (tumor necrosis factor-α), SOD (superoxide dismutase), and GSH-PX (glutathione peroxidase) were detected.

Results

Serums IL-1β, IL-6, and TNF-α concentrations in group S and group F were higher than those in group C (P < 0.01), while those inflammatory cytokines in group F were significantly lower than those in group S (P < 0.01); serum GSH-PX levels in group F were higher than group S (P < 0.01). The Morris water maze behavior test performance of group F was better than that of group S (P < 0.05).

Conclusion

Omega-3 PUFA can effectively improve postoperative inflammatory response, reduce the damage of antioxidant defense system, and improve postoperative cognitive function.

An Association Between C-Reactive Protein Levels and the Occurrence of Cognitive Dysfunction After Heart Valve Replacement

Background

Postoperative cognitive dysfunction (POCD) is defined as cognitive dysfunction related to inflammation after surgical procedures, which is common following cardiac surgery. Cognitive deficits are thought to result from a systemic inflammatory response. C-reactive protein (CRP) and other proinflammatory cytokines, which are released in response to inflammation, disrupt the blood–brain barrier and neurotransmission, resulting in POCD. This study aimed to determine the correlation between POCD and increased levels of CRP in patients who had undergone heart valve replacement.

Methods

This study comprised 32 patients with normal cognitive function undergoing heart valve replacement. The CRP levels were measured before surgery and on the second postoperative day, and cognitive function was examined via the Indonesian-adapted Montreal Cognitive Assessment (MOCA-INA) on the third postoperative day. Data were analyzed using Spearman correlation test.

Results

Of the 32 patients, 28 (87.5%) experienced POCD. The median level of CRP was 6.6 mg/dL (interquartile range: 4.0, 8.3 g/dL). According to Spearman correlation test, increased levels of CRP were significantly related to POCD following heart valve replacement (p = 0.003, r = 0.501). The receiver operating characteristic curve indicated that the CRP cutoff level was 3.345 mg/dL, and the sensitivity and specificity were 89.3% and 75%, respectively.

Conclusion

High expression level of CRP was correlated with POCD following heart valve replacement.

Impact of enhanced recovery after surgery protocol compliance on patients' outcome in benign hysterectomy and establishment of a predictive nomogram model

Background

Enhanced recovery after surgery (ERAS) pathways have been shown to improve clinical outcomes after surgery. Considering the importance of patient experience for patients with benign surgery, this study evaluated whether improved compliance with ERAS protocol modified for gynecological surgery which recommended by the ERAS Society is associated with better clinical outcomes and patient experience, and to determine the influence of compliance with each ERAS element on patients’ outcome after benign hysterectomy.

Methods

A prospective observational study was performed on the women who underwent hysterectomy between 2019 and 2020. A total of 475 women greater 18 years old were classified into three groups according to their per cent compliance with ERAS protocols: Group I: < 60% (148 cases); Group II:≥60 and < 80% (160 cases); Group III: ≥80% (167 cases). Primary outcome was the 30-day postoperative complications. Second outcomes included QoR-15 questionnaire scores, patient satisfaction on a scale from 1 to 7, and length of stay after operation. After multivariable binary logistic regression analyse, a nomogram model was established to predict the incidence of having a postoperative complication with individual ERAS element compliance.

Results

The study enrolled 585 patients, and 475 completed the follow-up assessment. Patients with compliance over 80% had a significant reduction in postoperative complications (20.4% vs 41.2% vs 38.1%, P < 0.001) and length of stay after surgery (4 vs 5 vs 4, P < 0.001). Increased compliance was also associated with higher patient satisfaction and QoR-15 scores (P < 0.001),. Among the five dimensions of the QoR-15, physical comfort (P < 0.05), physical independence (P < 0.05), and pain dimension (P < 0.05) were better in the higher compliance groups. Minimally invasive surgery (MIS) (P < 0.001), postoperative nausea and vomiting (PONV) prophylaxis (P < 0.001), early mobilization (P = 0.031), early oral nutrition (P = 0.012), and early removal of urinary drainage (P < 0.001) were significantly associated with less complications. Having a postoperative complication was better predicted by the proposed nomogram model with high AUC value (0.906) and sensitivity (0.948) in the cohort.

Conclusions

Improved compliance with the ERAS protocol was associated with improved recovery and better patient experience undergoing hysterectomy. MIS, PONV prophylaxis, early mobilization, early oral intake, and early removal of urinary drainage were of concern in reducing postoperative complications.

Trial registration

Chinese Clinical Trial Registry, ChiCTR1800019178. Registered on 30/10/2018.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12871-021-01509-0.

Impact of multimodal warming during general anaesthesia on postoperative cognitive dysfunction in elderly patients with gynaecological cancer: study protocol for a single-blinded randomised controlled trial

BACKGROUND

Cognitive impairment after anaesthesia and surgery is a recognised consequence. This often leads to poor health outcomes and increases healthcare resource utilisation and associated costs, especially in elderly people. However, thus far, there have not been any effective therapies for managing postoperative cognitive dysfunction (POCD). Furthermore, research on the association of multimodal warming with POCD and the clinical outcomes in older patients after gynaecological surgery has not been rigorous. For these reasons, our investigation aims to evaluate whether perioperative multimodal warming would reduce the incidence of POCD and improve prognosis in elderly patients with gynaecological cancer.

METHODS AND ANALYSIS

This is a single-centre, prospective, single-blinded randomised controlled trial. One hundred and fifty patients for gynaecological cancer surgery and 16 non-surgical controls aged 65 years or older will be studied in this trial. A series of neuropsychological tests will be completed to evaluate cognitive function in surgery patients before, at day 7 and 3 months after gynaecological cancer surgery. In addition, POCD and cognitive decline will be assessed using the reliable change index using the control group's results. The primary outcome is the prevalence of POCD in elderly gynaecological cancer surgery patients and association between perioperative multimodal warming and POCD.

ETHICS AND DISSEMINATION

The protocol for this prospective observational study was approved by the ethics committee of the West China Second University Hospital, Sichuan University (NO. KX215). Recruitment will commence in April 2021 and continue to April 2022. The findings of this trial will be disseminated in peer-reviewed journals and scientific meetings.

TRIAL REGISTRATION NUMBER

ChiCTR2100041663.

Effects of Apolipoprotein Ε ε4 allele on early postoperative cognitive dysfunction after anesthesia

BACKGROUND

Postoperative cognitive dysfunction (POCD) is one of the main causes of morbidity after noncardiac surgery; however, the pathogenic mechanisms of POCD have remained unclear until now. In this study, we performed a pilot study to investigate the association between apolipoprotein E (ApoE) ε4 and POCD in older patients undergoing intravenous anesthesia (IVA) and inhalation anesthesia (IAA).

METHODS

In total, 180 patients from Shenzhen People's Hospital were recruited and randomly divided into an IVA group and an IAA group. The IVA group and IAA group received propofol and sevoflurane treatment, respectively. Within 7 days after surgery, the mini-mental state examination (MMSE) was used daily to assess the cognitive function of both groups of patients. The genotypes of the ApoE gene were detected using the restriction fragment length polymorphism technique. In addition, the serum levels of (soluble protein-100β) S‑100β and (Interleukin- 6) L‑6 were also analyzed.

RESULTS

Compared to the preoperative and IVA groups, the MMSE score in the IAA group significantly decreased at 3 days after surgery. Furthermore, the IAA group had a higher percentage of patients who scored less than 25 points than the IVA group at 3 days after surgery. The decrease in the MMSE score was closely related to the ApoE ε4 allele in the IAA group, but this correlation was not observed in the IVA group. The levels of S‑100β and IL‑6 were increased sharply in patients with the ε4/ε4 genotype who received IAA compared with IVA at 1 day after surgery.

CONCLUSION

The results of the study indicated that the ApoΕ ε4/ε4 genotype was a risk factor for early POCD in older patients undergoing sevoflurane anesthesia.

Treatment with Histone Deacetylase Inhibitor Attenuates Peripheral Inflammation-Induced Cognitive Dysfunction and Microglial Activation: The Effect of SAHA as a Peripheral HDAC Inhibitor

It has been demonstrated that peripheral inflammation induces cognitive dysfunction. Several histone deacetylase (HDAC) inhibitors ameliorate cognitive dysfunction in animal models of not only peripheral inflammation but also Alzheimer's disease. However, it is not clear which HDAC expressed in the central nervous system or peripheral tissues is involved in the therapeutic effect of HDAC inhibition on cognitive dysfunction. Hence, the present study investigated the effect of peripheral HDAC inhibition on peripheral inflammation-induced cognitive dysfunction. Suberoylanilide hydroxamic acid (SAHA), a pan-HDAC inhibitor that is mainly distributed in peripheral tissues after intraperitoneal administration, was found to prevent peripheral inflammation-induced cognitive dysfunction. Moreover, pretreatment with SAHA dramatically increased mRNA expression of interleukin-10, an anti-inflammatory cytokine, in peripheral and central tissues and attenuated peripheral inflammation-induced microglial activation in the CA3 region of the hippocampus. Minocycline, a macrophage/microglia inhibitor, also ameliorated cognitive dysfunction. Furthermore, as a result of treatment with liposomal clodronate, depletion of peripheral macrophages partially ameliorated the peripheral inflammation-evoked cognitive dysfunction. Taken together, these findings demonstrate that inhibition of peripheral HDAC plays a critical role in preventing cognitive dysfunction induced by peripheral inflammation via the regulation of anti-inflammatory cytokine production and the inhibition of microglial functions in the hippocampus. Thus, these findings could provide support for inhibition of peripheral HDAC as a novel therapeutic strategy for inflammation-induced cognitive dysfunction.

Short term cognitive function after sevoflurane anesthesia in patients suspect to obstructive sleep apnea syndrome: an observational study

BACKGROUND

The obstructive sleep apnea syndrome (OSAS) is characterized by intermittent cerebral hypoxia which can cause cognitive alterations. Likewise, hypoxia induced neurocognitive deficits are detectable after general anesthesia using volatile anesthetics. The objective of this study was to evaluate the association between a moderate to high risk patients of OSAS and postoperative cognitive dysfunction after volatile anesthesia.

METHODS

In this single center prospective, observational study between May 2013 and September 2013, 46 patients aged 55 to 80 years with an estimated hospital stay of at least 3 days undergoing surgery were enrolled. Patients were screened using the STOP-BANG test with score of 3 or higher indicating moderate to high risk of OSAS. The cognitive function was assessed using a neuropsychological assessment battery, including the DemTect test for cognitive impairment among other tests e.g. SKT memory, the day before surgery and within 2 days after extubation.

RESULTS

Twenty-three of the 46 analyzed patients were identified with a moderate to high risk of OSAS. When comparing post- to preoperative phase a significant better performance for the SKT was found for both groups (p <  0.001). While the moderate to high risk group scores increased postoperative in the DemTect test, they decreased in the low risk group (p <  0.003). When comparing the changes between groups, the moderate to high risk patients showed significant better test result for DemTect testing after anaesthesia. This effect remained robust when adjusting for potential confounding variables using a two-factor ANOVA.

CONCLUSION

Compared to low risk, a moderate to high risk of OSAS based on the STOP-BANG score was associated with improved postoperative cognitive function measured by the DemTect test.

TRIAL REGISTRATION

The study was approved by the local Ethics committee (Ethikkommission der Medizinischen Fakultät der Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany) (reference number: 87_12 B ) on 19.04.2012.

The role of intraoperative hypotension on the development of postoperative cognitive dysfunction: a systematic review

STUDY OBJECTIVE

To clarify whether intraoperative hypotension contributes to the development of postoperative cognitive dysfunction.

DESIGN

A systematic review of prospective studies reporting on intraoperative hypotension and postoperative cognitive dysfunction in elective, non-cognitive impaired, adult surgical patients. PubMed, EMBASE and the Cochrane Library were searched up to the 1st of January 2021.

SETTING

Studies had to use a clear definition of hypotension, although differing definitions were accepted. Neurocognitive tests to determine postoperative cognitive dysfunction had to be done pre- and postoperatively, with a minimum follow-up of seven days postoperatively.

MEASUREMENTS

Risk of bias was assessed using the Cochrane Risk of Bias Tool 2.0 for randomized controlled trials and the Newcastle-Ottawa Scale for cohort studies.

MAIN RESULTS

Out of 941 studies screened, five randomized controlled trials and four cohort studies were included for qualitative analysis. Extensive methodological differences between studies were present hindering proper quantitive analysis. No studies reported statistically significant differences in incidence of postoperative cognitive dysfunction in hypo- compared to normotensive patients. Five studies reported exact incidences of postoperative cognitive dysfunction.

CONCLUSIONS

This systematic review showed no conclusive association between intraoperative hypotension and the development of postoperative cognitive dysfunction. Given the vast methodological differences of the included studies, the role of intraoperative hypotension in the development of postoperative cognitive dysfunction remains uncertain. Future research into the association between intraoperative hypotension and postoperative cognitive dysfunction should be conducted in a standardized manner.

Patient-Reported Cognitive Outcomes Following Cardiac Surgery: A Descriptive Review

A descriptive review was conducted to evaluate the evidence of cognitive patient-reported outcome measures (PROMs) following cardiac surgery. The search of electronic databases resulted in 400 unique manuscripts. Nine studies met the criteria to be part of the final review. Results of the review suggest that there are few validated PROMs that assess cognitive function in the cardiac surgical population. Furthermore, PROMs have not been used to assess overall cognitive function following cardiac surgery within the past decade. However, one domain of cognitive function—memory—was described, with up to half of patients reporting a decline postoperatively. Perceived changes in cognitive function may impact health-related quality of life and a patient’s overall view of the success of their surgery. Early identification of cognitive changes measured with PROMs may encourage earlier intervention and improve patient-centered care. In clinical practice, nurses may be in the best position to administer PROMs preoperatively and postoperatively.

Gut microbiota: a new player in the pathogenesis of perioperative neurocognitive disorder?

Perioperative neurocognitive disorder (PND), including postoperative delirium and postoperative cognitive dysfunction (POCD), is a common postoperative complication in elderly patients, who represent an expanding segment of our population. PND is a multifactorial disease resulting in higher morbidity and mortality. The precise mechanism of PND is yet to be fully delineated. Identifying the modifiable risk factors and mechanisms for PND would be an important step forward in preventing such adverse events and thus improving patients' outcomes. It is increasingly recognized that gut microbiota also manifest effects in the central nervous system via the microbiota-gut-brain axis, which has emerged as an important player in shaping aspects of behavior and cognitive function. Recent studies have found that patients with cognitive dysfunction after surgery and anesthesia have obvious gut microbiome disorders. These findings are paralleled by a growing body of preclinical investigations aimed at better understanding how surgery and anesthesia affect the central nervous system and possibly contribute to cognitive decline. Here, we present a broad topical review of the literature supporting the role of gut microbiota in PND. We provide an overview of the mechanisms underlying the pathogenesis of PND from pre-clinical and human studies. Therefore, gut microbiota could be a putative therapeutic target for PND in the future.

Postoperative Cognitive Dysfunction and the Protective Effects of Enriched Environment: A Systematic Review

BACKGROUND

Currently, the number of individuals who undergo surgery is greatly increased. As a consequence, postoperative cognitive dysfunction (POCD) has gradually gained more attention.

SUMMARY

POCD is a perioperative complication requiring sensitive preoperative and postoperative neuropsychiatric tests, and its incidence in both cardiac and noncardiac surgery is high, especially in elderly individuals. Surgical, patient, and anesthetic factors may all lead to the occurrence and development of POCD. The key mechanism of POCD may be the inflammatory response of the central nervous system during surgery, which is similar to that of Alzheimer's disease (AD). Enriched environment (EE), a factor that can significantly improve and prevent neurodegenerative diseases, may have a beneficial effect on POCD. Key Messages: This review aims to elucidate the mechanism of the occurrence and development of POCD, analyze the possible influence of EE on POCD at the molecular level, and provide a direction for its treatment.

Hydrogen sulfide attenuates postoperative cognitive dysfunction through promoting the pathway of Warburg effect-synaptic plasticity in hippocampus

Postoperative cognitive dysfunction (POCD) is deemed to a severe surgical complication without effective treatment. Previous work has confirmed the important modulatory role of hydrogen sulfide (H₂S) in cognitive function. This study was proposed to explore whether H₂S relieves POCD and the possible mechanisms. We demonstrated that NaHS (a donor of H₂S) reversed the inhibited endogenous H₂S generation in the hippocampus of postoperative rats. NaHS attenuated the cognitive impairment of postoperative rats in the Y-maze, Novel object recognition, and Morris water maze tests. NaHS enhanced the expressions of synaptic plasticity-related proteins, synapsin-1 and PSD-95, increased the synaptic density, and decreased the destruction of synaptic structures in the hippocampus of postoperative rats. Moreover, NaHS promoted Warburg effect in the hippocampus of postoperative rats, as reflected by increases in the expressions of hexokinase 2, pyruvate kinase M2, lactate dehydrogenase A, and pyruvate dehydrogenase kinase 1, an enhancement in the content of lactate, and a reduction in the expression of pyruvate dehydrogenase. The inhibitor of Warburg effect, 2-Deoxy-D-glucose (2-DG), not only reversed NaHS-enhanced Warburg effect in the hippocampus of postoperative rats, but also significantly abolished NaHS-exerted protective effect on cognitive function. Furthermore, 2-DG reversed NaHS-exerted enhancement in the expressions of synapsin-1 and PSD-95, increase in the synaptic density, and decrease in the destruction of synaptic structures in the hippocampus of postoperative rats. Collectively, these results indicate that H₂S alleviates POCD through enhancing hippocampal Warburg effect, which subsequently improves synaptic plasticity in the hippocampus.

Effect of perioperative intravenous lidocaine on the incidence of short-term cognitive function after noncardiac surgery: A meta-analysis based on randomized controlled trials

OBJECTIVES

Postoperative cognitive dysfunction is a debilitating postoperative complication. The perioperative neuroprotective effect of lidocaine has conflicting results.

METHODS

In this qualitative review of randomized controlled clinical trials on the perioperative use of lidocaine, we report the effects of intravenous lidocaine on brain function after noncardiac surgery. Studies were identified from PubMed, MEDLINE, and Cochrane Central Register.

RESULTS

Of the 453 retrieved studies, 4 randomized trials were included. No significant association between the use of lidocaine postoperative cognitive states was found (risk ratio 0.67; 95% CI -0.02 to 1.36; I² 89%; p = .06).

CONCLUSIONS

Current evidence cannot suggest that perioperative intravenous use of lidocaine has pharmacological brain neuroprotection after noncardiac surgery. All the included studies were small-scale research, and the total number of participants was small; the results should be interpreted with caution.

Repeated propofol exposure-induced neuronal damage and cognitive impairment in aged rats by activation of NF-κB pathway and NLRP3 inflammasome

BACKGROUND

Elderly patients receive propofol at regular intervals for sedation during gastrointestinal endoscopy. However, the link between cognition and intermittent propofol exposure remains unclear. Thus, we used aged rats to investigate the effect of propofol on cognition.

METHODS

The study included two parts. In the first part, aged (18-20 months old) male Sprague-Dawley rats underwent intermittent intraperitoneal injection of propofol (200 mg/kg) or intralipid, every 9 days or once a day. In the second part, some aged rats received intraperitoneal injection of Bay 11-7082 (1 mg/kg), a specific inhibitor of NF-κB, 30 min before propofol injection. Memory tests were performed to evaluate cognition 24 h after the entire treatment. The hippocampal neuronal damage was assessed by TUNEL staining. The hippocampal levels of p-NF-κB p65, NLRP3, caspase-1 p20, and cleaved caspase-3 were detected by western blotting. The hippocampal and serum levels of IL-1β, IL-6, and TNF-α were evaluated using ELISA.

RESULTS

There were no differences in the behavioral tests, hippocampal neuronal damage, and neuroinflammation between groups given intralipid and propofol treatment every 9 days. However, repeated propofol treatment once a day promoted activation of NF-κB and the NLRP3 inflammasome, inducing cognitive impairment and neuroinflammation. Interestingly, pretreatment with Bay-11-7082 not only inhibited NF-κB/NLRP3 inflammasome activation, but also attenuated neuronal damage and cognitive dysfunction in aged rats exposed to daily propofol treatment.

CONCLUSIONS

Intermittent propofol treatment every 9 days may be safe for aged rats. However, propofol treatment once a day could impair the cognition of aged rats, partly through the activation of the NF-κB pathway and NLRP3 inflammasome, which may be a potential targets for the treatment of cognitive impairment in elderly patients.

Correlation Between Plasma CircRNA-089763 and Postoperative Cognitive Dysfunction in Elderly Patients Undergoing Non-cardiac Surgery

In our previous experiment, we found that there were abnormal levels of circRNA-089763 in the plasma exosomes of patients with postoperative cognitive dysfunction (POCD) after cardiac surgery. Therefore, the aim of this study was to further investigate the relationship between plasma circRNA-089763 level and POCD in elderly patients after non-cardiac surgery. A prospective cohort study was conducted to select elderly patients undergoing elective non-cardiac surgery. A total of 72 patients were enrolled in this study, and cognitive functions were assessed 1 day before and 3 days after surgery by a series of neuropsychological measurements. Next, patients were divided into POCD and non-POCD (NPOCD) groups according to the Z score method. Blood was collected the day before and 3 days after surgery, and the plasma circRNA-089763 level was detected by quantitative real-time polymerase chain reaction (qRT-PCR). Then, the difference and correlation in plasma circRNA-089763 levels between the POCD and NPOCD groups were analyzed. On the third day after surgery, the incidence of POCD was 30.56%. The relative level of circRNA-089763 in the POCD group was 2.41 times higher than that in the NPOCD group (t = 4.711, p < 0.001), patients in POCD group had higher age (t = 5.971, p < 0.001), higher American Society of Anesthesiologists classification (χ² = 14.726, p < 0.001), less years of education (t = 2.449, p = 0.017), more intraoperative blood loss (t = 3.196, p = 0.002), and higher visual analog scale (VAS) scores (t = 10.45, p < 0.001). The binary logistic regression analysis showed that the circRNA-089763 level, age, and intraoperative blood loss were independently associated with POCD (OR: 2.75, 95% CI: 1.261–5.999, p = 0.011; OR: 1.32, 95% CI: 1.114–1.565, p = 0.001; OR: 1.017, 95% CI: 1.004–1.03, p = 0.011). These results demonstrated that the circRNA-089763 plasma level was related to POCD after non-cardiac surgery in elderly patients.

Short-term memory impairment in patients undergoing general anesthesia and its contributing factors

Background:

Short-term memory disorder following surgery and anesthesia is a common complication of anesthesia and a common complaint of the patients.

Aims:

This study was designed to assess memory impairment in patients undergoing elective surgery, investigate the effect of general anesthesia (GA) on memory, and identify the factors contributing to it, as well as the specific effect of anesthesia on each of the memory domains.

Setting and Design:

This cross-sectional study was performed in a university hospital.

Methods and Materials:

Patients with the American Society of Anesthesiologists (ASA) Class I, II, and III who were candidates for elective abdominal surgery were enrolled. Patients answered several questions based on the Wechsler Memory Scale–Revised V (WMS-R-V), a standardized questionnaire, minutes before entering the operating room (OR) and again after 24 h postoperation, and the differences were recorded.

Statistical Analysis:

Analysis was performed using T-independent and Chi-square tests with Pearson's coefficient and Fischer's exact test and Man–Whitney test. Data were analyzed using the Statistical Package for the Social Sciences (SPSS) software.

Results:

Four hundred patients (198 females and 202 males) with a mean age of 50.75 years were enrolled in our study. Our study results showed that short-term memory after GA was significantly decreased compared with preanesthesia (P < 0.05). There was no significant relationship between memory disorder following GA and gender (P = 0.18) or comorbidities (P = 0.138). However, older age was found to be a contributing factor to memory loss following GA (P < 0.001). The highest and lowest effect of GA were found on the number repeat (45.2%) and personal information (16.2%) domain of the memory.

Conclusion:

GA significantly reduces the patient's short-term memory after the surgery.

NLRP3 inflammasomes are involved in the progression of postoperative cognitive dysfunction: from mechanism to treatment

Postoperative cognitive dysfunction (POCD) involves patient memory and learning decline after surgery. POCD not only presents challenges for postoperative nursing and recovery but may also cause permanent brain damage for patients, including children and the aged, with vulnerable central nervous systems. Its occurrence is mainly influenced by surgical trauma, anesthetics, and the health condition of the patient. There is a lack of imaging and experimental diagnosis; therefore, patients can only be diagnosed by clinical observation, which may underestimate the morbidity, resulting in decreased treatment efficacy. Except for symptomatic support therapy, there is a relative lack of effective drugs specific for the treatment of POCD, because the precise mechanism of POCD remains to be determined. One current hypothesis is that postoperative inflammation promotes the progression of POCD. Accumulating research has indicated that overactivation of NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) inflammasomes contribute to the POCD progression, suggesting that targeting NLRP3 inflammasomes may be an effective therapy to treat POCD. In this review, we summarize recent studies and systematically describe the pathogenesis, treatment progression, and potential treatment options of targeting NLRP3 inflammasomes in POCD patients.

Dysfunction of inflammation-resolving pathways is associated with postoperative cognitive decline in elderly mice

BACKGROUND

Postoperative cognitive dysfunction (POCD) refers to a reversible, perioperative mental disorder. POCD increases the likelihood of postoperative complications and the risk for postoperative mortality, typically among elderly patients (age 65 or older). The importance of the cholinergic anti-inflammatory pathway (CAP) in resolving neuro-inflammatory and cognitive decline caused by sterile trauma has been recognized. We speculate that the POCD in elderly mice is associated with dysfunction of CAP.

METHODS

Mice were assigned to several groups (n = 5 in each group): AM (adult mice) Sham, AM (adult mice) Surgery, EM (elderly mice) Sham, EM (elderly mice) Surgery, and EMP (elderly mice with PNU) Surgery. At 24 h after surgery, assessed the cognitive levels. Pro-inflammatory cytokines in peripheral blood and splenic monocytes (TNF-α, IL-6 and IL-10) were assessed by ELISA and qPCR. Levels of M2 macrophages in hippocampus were visualized by immunofluorescence. Detecting CD11b/c⁺α7 nAChR⁺ cells in the spleens with flow cytometry.

RESULTS

At postoperative 24 h, elderly mice exhibited significantly increased POCD compared with adult mice. The proinflammatory factor TNF-α and IL-6 were higher among elderly surgery mice (EM) compared with adult surgery (AM) and elderly-P surgery mice (EM-P); the anti-inflammatory factor IL-10 and M2 macrophages were lower among EM surgery mice compared with AM surgery and EM-P surgery mice. The CD11b/c⁺α7 nAChR⁺ population of splenocytes was reduced in the EM surgery mice.

CONCLUSIONS

The exaggerated and persistent cognitive decline and inflammatory response among elderly mice were associated with dysfunction of CAP, and these phenomena were reversed by α7nAch receptor agonists.

Sevoflurane-induced inflammation development: involvement of cholinergic anti-inflammatory pathway

Chronic inflammation plays an important role in the mechanisms underpinning the development of anesthesia-induced cognitive dysfunction. However, less is known about how anesthesia causes inflammation. One possibility is that the inflammation is related to alteration of the activity of the alpha 7 nicotinic acetylcholine receptor cholinergic anti-inflammatory pathway. This study analyzed the effect of sevoflurane administration on the cognitive function by using a novel object recognition test and Y-maze test, and on acetylcholinesterase activity and expression in hippocampal tissue by using an acetylcholinesterase assay kit and quantitative real-time PCR. This study also evaluated the effect of alpha 7 nicotinic acetylcholine receptor agonist PNU-282987 and antagonist methyllycaconitine on cognitive function and the level of hippocampal tumor necrosis factor-α in aged rats exposed to sevoflurane anesthesia. We found that 3% sevoflurane significantly impaired cognitive function and increased acetylcholinesterase activity by upregulating its expression in hippocampal tissue. Sevoflurane-induced impairment of cognitive function was significantly rescued by PNU-282987 but aggravated by methyllycaconitine. In addition to impairment of cognitive function, sevoflurane also significantly increased tumor necrosis factor-α level in plasma and hippocampal tissue. Similarly, this sevoflurane-induced change of tumor necrosis factor-α level in rats was antagonized by PNU-282987 but amplified by methyllycaconitine. In conclusion, our data show that the development of inflammation in sevoflurane-induced cognitive decline is associated with the downregulation of alpha 7 nicotinic acetylcholine receptor cholinergic anti-inflammatory pathway in aged rats.

Acetate attenuates perioperative neurocognitive disorders in aged mice

Perioperative neurocognitive disorders are common in elderly patients who have undergone surgical procedures. Neuroinflammation induced by microglial activation is a hallmark of these neurological disorders. Acetate can suppress inflammation in the context of inflammatory diseases. We employed an exploratory laparotomy model with isoflurane anesthesia to study the effects of acetate on perioperative neurocognitive disorders in aged mice. Neurocognitive function was assessed with open-field tests and Morris water maze tests 3 or 7 days post-surgery. Acetate ameliorated the surgery-induced cognitive deficits of aged mice and inhibited the activation of IBA-1, a marker of microglial activity. Acetate also reduced expression of inflammatory proteins (tumor necrosis factor-α, interleukin-1β and interleukin-6), oxidative stress factors (NADPH oxidase 2, inducible nitric oxide synthase and reactive oxygen species), and signaling molecules (nuclear factor kappa B and mitogen-activated protein kinase) in the hippocampus. BV2 microglial cells were used to verify the anti-inflammatory effects of acetate in vitro. Acetate suppressed inflammation in lipopolysaccharide-treated BV2 microglial cells, but not when GPR43 was silenced. These results suggest that acetate may bind to GPR43, thereby inhibiting microglial activity, suppressing neuroinflammation, and preventing memory deficits. This makes acetate is a promising therapeutic for surgery-induced neurocognitive disorders and neuroinflammation.

Impact of Sevoflurane Versus Propofol Anesthesia on Post-Operative Cognitive Dysfunction in Elderly Cancer Patients: A Double-Blinded Randomized Controlled Trial

Background

Research on the clinical outcomes of surgical patients anaesthetized with sevoflurane and the association of sevoflurane with post-operative cognitive dysfunction (POCD) is scarce. We evaluated whether sevoflurane-based anesthesia increased the incidence of POCD and worsened prognosis compared to propofol-based anesthesia in elderly cancer patients.

Material/Methods

This single-center, prospective, double-blind randomized controlled trial included 234 patients aged 65 to 86 years undergoing tumor resection who received sevoflurane-based (Group S) or propofol-based (Group P) anesthesia during surgery. A series of neuropsychological tests was performed to evaluate cognitive function before surgery and at 7 days and 3 months post-operation, and the results were compared to those of healthy controls.

Results

At 7 days post-operation there were no significant differences in the incidence of POCD between patients who received sevoflurane-based or propofol-based anesthesia during surgery: Group S was at 29.1% (32 out of 110 patients) versus Group P at 27.3% (30 out of 110), P=0.764. At 3 months, Group S was at 11.3% (12 out of 106 patients) versus Group P at 9.2% (10 out of 109), P=0.604. During the first 2 days post-operation, the QoR-40 global score was significantly lower in Group S compared to Group P [POD 1: P=0.004; POD 2: P=0.001]. There were no significant differences in in-hospital post-operative complications, post-operative length of hospital stay, all-cause mortality at 30 days, and 3 months post-operation, or post-operative quality of life at 3 months between patients in Group S and Group P.

Conclusions

Sevoflurane-based anesthesia did not increase the incidence of POCD compared to propofol-based anesthesia at 7 days or 3 months post-operation or impact short-term post-operative prognosis.

Application of Acupuncture to Attenuate Immune Responses and Oxidative Stress in Postoperative Cognitive Dysfunction: What Do We Know So Far?

Postoperative cognitive dysfunction (POCD) is a common sequela following surgery and hospitalization. The prevention and management of POCD are important during clinical practice. POCD more commonly affects elderly patients who have undergone major surgery and can result in major decline in quality of life for both patients and their families. Acupuncture has been suggested as an effective intervention for many neurological disorders. In recent years, there are increasing interest in the use of acupuncture to prevent and treat POCD. In this review, we summarized the clinical and preclinical evidence of acupuncture on POCD using a narrative approach and discussed the potential mechanisms involved. The experimental details and findings of studies were summarized in tables and analyzed. Most of the clinical studies suggested that acupuncture before surgery could reduce the incidence of POCD and reduce the levels of systematic inflammatory markers. However, their reliability is limited by methodological flaws. Animal studies showed that acupuncture reduced cognitive impairment and the associated pathology after various types of surgery. It is possible that acupuncture modulates inflammation, oxidative stress, synaptic changes, and other cellular events to mitigate POCD. In conclusion, acupuncture is a potential intervention for POCD. More clinical studies with good research design are required to confirm its effectiveness. At the same time, findings from animal studies will help reveal the protective mechanisms, in which systematic inflammation is likely to play a major role.

Up-regulation of miR-106a targets LIMK1 and contributes to cognitive impairment induced by isoflurane anesthesia in mice

BACKGROUND

Postoperative cognitive dysfunction (POCD) had a great relationship with anesthesia during surgery, and miRNAs have been found involved in anesthesia-induced cognitive impairment.

OBJECTIVE

To explore the role and potential mechanism of miR-106a in isoflurane anesthesia-induced cognitive impairment.

METHODS

Adult male mice were treated with isoflurane anesthesia; Morris water maze tests and fear conditioning tests were performed; and expression levels of miR-106a and LIMK1 were determined by quantitative real-time PCR (qRT-PCR) and western blot. Dual luciferase reporter assay was used to determine the binding of miR-106a and 3'UTR of LIMK1. To verify the role of miR-106a, antagomir of miR-106a were intrahippocampally injected. Finally, expression of BCL2 apoptosis regulator (Bcl-2), LIM domain kinase 1 (LIMK1), BCL2-associated X, apoptosis regulator (Bax) and cleaved caspase3 was determined by western blot.

RESULTS

In isoflurane anesthesia-treated group (IS), the percentage of target quadrant dwell time was significantly lower and the escape latency was significantly higher than in the control group (sham), and the freezing behavior of IS was significantly less in contextual fear conditioning tests. Expression levels of miR-106a were increased and those of LIMK1 were decreased in response to IS. Dual luciferase reporter assay showed that miR-106a could bind with the 3'UTR of LIMK1. Decreased expression levels of miR-106a improved the cognitive impairment of the mice treated with isoflurane. Intrahippocampally injected antagomir of miR-106a also increased LIMK1 and Bcl-2 levels, decreased the BAX and cleaved caspase3 expression levels in the mice treated with isoflurane.

CONCLUSION

Decrease of LIMK1 expression by miR-106a played an important role in isoflurane anesthesia-induced cognitive impairment.

Exogenous hydrogen sulfide alleviates surgery-induced neuroinflammatory cognitive impairment in adult mice by inhibiting NO signaling

Background

To investigate the effect and mechanisms of exogenous hydrogen sulfide in surgery-induced neuroinflammatory cognitive dysfunction.

Methods

C57BL/6 J male mice (n = 140) were used and randomly divided into seven groups: the sham group, surgery group, GYY4137 group, L-NAME group, surgery+GYY4137 group, surgery +L-NAME group, and surgery+GYY4137 + L-NAME group. After the interventions, open field tests (OFT) and the Morris water maze (MWM) test were conducted to evaluate learning and memory abilities in the mice. ELISAs, nitrate reductase assays, and Western blots (WB) were conducted to evaluate interleukin-1 beta (IL-1β), tumor necrosis factor-alpha (TNF-α), nitric oxide (NO), inducible nitric oxide synthase (iNOS), malondialdehyde (MDA), and antioxidant enzyme superoxide dismutase (SOD) levels. Furthermore, the expression level of microglial marker ionized calcium binding adaptor molecule 1 (IBA) in the hippocampal CA1 and CA3 areas was detected by an immunohistochemical (IHC) assay and apoptotic cells were observed using terminal deoxynucleotidyl transferase dUTP end-labeling (TUNEL) staining kits.

Results

We found that surgery induced neuroinflammatory cognitive dysfunction, oxidative stress, microglial activation, and cell apoptosis in the hippocampus. Moreover, following surgery, NO and iNOS levels were elevated in the hippocampus. Notably, all the effects caused by surgery were reversed by the H₂S donor GYY4137 or the iNOS inhibitor N(gamma)-nitro-L-arginine methyl ester (L-NAME). However, the combined application of GYY4137 and L-NAME was not superior to treatment with either agent alone and the effect of GYY4137 was similar to that of L-NAME.

Conclusion

The long-acting hydrogen sulfide donor GYY4137 had an ability to reversed the cognitive deficits and inflammation caused by carotid artery exposure surgery. This implies that NO signaling pathways might participate in this process. These results indicate that exogenous H₂S may be a promising therapy for POCD.

Influence of postoperative analgesia on systemic inflammatory response and postoperative cognitive dysfunction after femoral fractures surgery: a randomized controlled trial

BACKGROUND AND OBJECTIVES

To investigate the possible effect of postoperatively applied analgesics-epidurally applied levobupivacaine or intravenously applied morphine-on systemic inflammatory response and plasma concentration of interleukin (IL)-6 and to determine whether the intensity of inflammatory response is related to postoperative cognitive dysfunction (POCD).

METHODS

This is a randomized, prospective, controlled study in an academic hospital. Patients were 65 years and older scheduled for femoral fracture fixation from July 2016 to September 2017. Inflammatory response was assessed by leukocytes, neutrophils, C reactive protein (CRP) and fibrinogen levels in four blood samples (before anesthesia, 24 hours, 72 hours and 120 hours postoperatively) and IL-6 concentration from three blood samples (before anesthesia, 24 hours and 72 hours postoperatively). Cognitive function was assessed using the Mini-Mental State Examination preoperatively, from the first to the fifth postoperative day and on the day of discharge.

RESULTS

The study population included 70 patients, 35 in each group. The incidence of POCD was significantly lower in the levobupivacaine group (9%) than in the morphine group (31%) (p=0.03). CRP was significantly lower in the levobupivacaine group 72 hours (p=0.03) and 120 hours (p=0.04) after surgery. IL-6 values were significantly lower in the levobupivacaine group 72 hours after surgery (p=0.02). The only predictor of POCD in all patients was the level of IL-6 72 hours after surgery (p=0.03).

CONCLUSIONS

There is a statistically significant association between use of epidural levobupivacaine and a reduction in some inflammatory markers. Postoperative patient-controlled epidural analgesia reduces the incidence of POCD compared with intravenous morphine analgesia in the studied population.

TRIAL REGISTRATION NUMBER

NCT02848599.

Compound K attenuated hepatectomy-induced post-operative cognitive dysfunction in aged mice via LXRα activation

AIMS

Post-operative cognitive dysfunction (POCD) occurs after major surgery in elderly patients and affects the quality of patients' lives. The present study aims to explore the protective effects and possible mechanisms of compound K in old mice with POCD caused by partial hepatectomy.

METHODS

Sixteen month-old mice were administered different doses of compound K from the 8th day to 14th day after partial hepatectomy. Cognitive function was subsequently measured with a Morris water-maze (MWM) test. Serum inflammatory cytokine levels were measured by magnetic bead panel; levels of cytokines in the hippocampus were analyzed using immunohistochemistry and immunoblotting. The mRNA levels of target genes were measured using real-time PCR.

RESULTS

Compared with the model group, MWM scores were significantly attenuated at days 10 and 14 post-surgery in mice receiving compound K (10, 30 mg/kg) in a dose-dependent manner. Both systemic and local cytokine levels were reduced after treatment of compound K. The alterations in serum lipids were independent of the attenuation of POCD syndrome. An inhibitor of liver X receptor-α (LXRα), GGPP, reversed the effects of compound K.

CONCLUSIONS

The results provide evidence for an alleviation of POCD by compound K via local inflammation inhibition in hippocampus tissue; furthermore, the data suggests the mechanism involves the LXRα pathway. The present study supports further evaluation of compound K as a potential effective modulator for POCD.

Effects of sevoflurane and desflurane on early cognitive changes after thyroid surgery: interim results

The study is being conducted at the 1st Department of Anaesthesiology, the Centre of Abdominal Surgery, the Centre of Anaesthesiology, Intensive Care and Pain Management of Vilnius University Hospital Santaros Klinikos.

Background

These are primary results of a randomized double-blinded study comparing postoperative changes in cognitive functions and the effect of desflurane and sevoflurane on these changes.

Materials and methods

The study includes patients of ≥40 years of age undergoing elective thyroid surgery under general anaesthesia. Patients were randomly allocated to either sevoflurane or desflurane group. Cognitive testing (memory, attention, and reasoning tasks) was performed a day before surgery and repeated 24 hours postoperatively. A decrease of 20% in the postoperative score was considered as postoperative cognitive dysfunction (POCD).

Results

At present 38 patients are included in the study. Median decrease in the postoperative score was 2.7% (IQR 16.7). The incidence of POCD was 2.6%. Significantly decreased memory scores were observed in 15.8% of patients. Both study groups were comparable based on demography, duration of anaesthesia, intraoperative opioids, postoperative pain, and satisfaction. No difference was found in the cognitive score comparing sevoflurane and desflurane groups, except for memory tasks where the sevoflurane group performed worse (p = 0.01).The age or the duration of anaesthesia did not affect postoperative scores. Postoperative satisfaction negatively correlated with the memory score (r = -0.35, p = 0.03). Postoperative satisfaction correlated with the reasoning score (r = -0.55; p < 0.01) and the total score (r = -0.42; p = 0.03) in the sevoflurane group. Likewise, temperature in the sevoflurane group correlated with the memory score (r = -0.58; p = 0.02).

Conclusions

The desflurane group performs better in memory tasks, but no such advantage is found in the total cognitive score. In contrast to the age or anaesthesia duration, intraoperative temperature and postoperative satisfaction may affect postoperative cognitive performance.

General Anesthetic Use in Fragile X Spectrum Disorders

The fragile X premutation is characterized by a repeat expansion mutation (between 55 to 200 CGG repeats) in the fragile X mental retardation 1 (FMR1) gene, which leads to RNA toxicity at the cellular level. This may cause patients with the premutation to be particularly susceptible to environmental toxins, which could manifest clinically as new or worsening ataxia and memory loss. Multiple published case reports have also suggested general anesthetics as a potential toxin leading to negative side effects when used in patients with fragile X-associated disorders. However, at this time, there have been no formal research studies regarding cellular changes or long-term clinical manifestations after general anesthetic use in this population. This review aims to highlight previous case reports regarding sequelae related to general anesthetic use in fragile X-associated disorders. New case reports related to this phenomenon are also included.

Malondialdehyde on postoperative day 1 predicts postoperative cognitive dysfunction in elderly patients after hip fracture surgery

Background: Postoperative cognitive dysfunction (POCD) is a great problem for anesthetized subjects and is associated with poor short- and long-term outcomes. We explored promising predictors for POCD in elderly patients after hip fracture surgery.Methods: Elderly subjects (aged ≥65 years) undergoing surgery for hip fracture were consecutively recruited. Neuropsychological assessments were performed 1 day preoperatively (baseline) and 7 days postoperatively, and POCD was defined using the 'Z scores' method. Clinical data and laboratory tests were compared between patients with and without POCD development. Binary univariate and multivariate logistic regression analyses were conducted for risk factor assessment. Receiver operating characteristic (ROC) curve analysis was performed to investigate the predictive value of malondialdehyde (MDA) on postoperative day 1 (POD1) for POCD.Results: A total of 198 patients were finally enrolled in the analysis and 51 patients exhibited POCD within 7 postoperative days, with an incidence rate of 25.8%. MDA expression on POD1 (OR: 1.12, 95%CI: 1.03-1.23, P=0.017) was the only independent risk factor for POCD according to the final multivariate logistic regression analysis. ROC curve analysis indicated that MDA on POD1 was a predictor for POCD, with an area under the curve (AUC) of 0.683 and 95%CI of 0.590-0.775 (P<0.001).Conclusions: In conclusion, we demonstrated that MDA on POD1 was an independent risk factor for POCD in elderly subjects undergoing hip fracture surgery.

Effects of Memantine in a Mouse Model of Postoperative Cognitive Dysfunction

Persistent impairment in cognitive functioning postoperatively is reported by clinical and animal studies, and is labeled as postoperative cognitive dysfunction (POCD). Evidence points to an exaggerated neuroinflammatory response resulting from peripheral systemic inflammation after surgery, with subsequent cytokine-induced glutamatergic excitotoxicity and synaptic impairment. These immunological changes, among many others, are also observed in Alzheimer’s disease. Memantine is an N-methyl-D-aspartate receptor (NMDAR) antagonist commonly used to treat Alzheimer’s disease. Surprisingly, little research exists on the role of memantine in preventing POCD. The purpose of this study is to investigate the effects of memantine on a spectrum of cognitive functions postoperatively. Mice were divided into 3 groups and each received treatment for 4 weeks. Placebo groups received a placebo then underwent either a sham procedure or a laparotomy procedure. The memantine group received memantine hydrochloride then underwent a laparotomy procedure. Cognitive tests were performed on postoperative days (POD) 1 and 7. Compared to sham-operated mice, placebo groups that underwent a laparotomy procedure showed impaired memory in the Morris water maze test, higher anxiety-like behavior in the open field and the elevated plus maze tests, increased depression-like behavior in the tail suspension test, and lack of preference for social novelty in the three-chamber test. On the other hand, memantine-treated mice that underwent a laparotomy procedure showed enhanced memory on POD7, improved depression-like behavior on POD1 and POD7, enhanced preference for social novelty on POD1, and no improvement in anxiety-like behavior. These findings suggest a potential protective effect of memantine in mice postoperatively on memory, depression-like behavior, and preference for social novelty.