Insulin resistance plays a potential role in postoperative cognitive dysfunction in patients following cardiac valve surgery

Efficacy and safety of intranasal insulin on postoperative cognitive dysfunction in elderly patients after laparoscopic radical resection of colorectal cancer: a double-blind pilot study

Objective

To evaluate the efficacy and safety of intranasal insulin on postoperative cognitive dysfunction (POCD) in elderly patients after laparoscopic radical resection of colorectal cancer.

Methods

Older patients scheduled for laparoscopic radical resection of colorectal cancer at Beijing Luhe Hospital, Capital Medical University, between August 2023 and November 2023, were enrolled in this double-blind pilot study. Patients were randomized to the control and insulin groups at a 1:1 ratio. The primary outcome was the rate of POCD at postoperative 7 days.

Results

A total of 61 patients (30 in the insulin group) were analyzed. The insulin group had a significantly lower POCD rate compared with the control group at postoperative day 7 [4(13.3%) vs. 12 (38.7%), p = 0.024]. The serum levels of IL-6, TNF-α and S100β at T2-5 in the insulin group were significantly lower than those of the control group (IL-6: mean difference at T2, -4.14, p = 0.036; T3, -3.84, p = 0.039; T4, -3.37, p = 0.013; T5, -2.57, p = 0.042; TNF-α: mean difference at T2, -3.19, p = 0.002; T3, -2.35, p = 0.028; T4, -2.30, p = 0.019; T5, -1.96, p = 0.0181; S100β: mean difference at T2, -8.30, p = 0.019; T3, -23.95, p = 0.020; T4, -20.01, p = 0.023; T5, -17.67, p = 0.010). No insulin allergic reactions, nasal irritation, or hypoglycemic reactions were observed in either of the groups.

Conclusion

Intranasal insulin may decrease the risk of POCD and inhibit the elevated serum IL-6, TNF-α, and S100β levels in elderly patients after laparoscopic radical resection of colorectal cancer, which proves that intranasal insulin may be a promising therapeutic option for POCD.

Clinical trial registration

Identifier, ChiCTR2300074423.

Abnormal metabolism in hepatic stellate cells: Pandora's box of MAFLD related hepatocellular carcinoma

Metabolic associated fatty liver disease (MAFLD) is a significant risk factor for the development of hepatocellular carcinoma (HCC). Hepatic stellate cells (HSCs), as key mediators in liver injury response, are believed to play a crucial role in the repair process of liver injury. However, in MAFLD patients, the normal metabolic and immunoregulatory mechanisms of HSCs become disrupted, leading to disturbances in the local microenvironment. Abnormally activated HSCs are heavily involved in the initiation and progression of HCC. The metabolic disorders and abnormal activation of HSCs not only initiate liver fibrosis but also contribute to carcinogenesis. In this review, we provide an overview of recent research progress on the relationship between the abnormal metabolism of HSCs and the local immune system in the liver, elucidating the mechanisms of immune imbalance caused by abnormally activated HSCs in MAFLD patients. Based on this understanding, we discuss the potential and challenges of metabolic-based and immunology-based mechanisms in the treatment of MAFLD-related HCC, with a specific focus on the role of HSCs in HCC progression and their potential as targets for anti-cancer therapy. This review aims to enhance researchers' understanding of the importance of HSCs in maintaining normal liver function and highlights the significance of HSCs in the progression of MAFLD-related HCC.

Safety of intranasal insulin administration in patients undergoing cardiovascular surgery: An open-label, nonrandomized, dose-escalation study

Objective

This study aimed to determine the maximum safe dose of intranasal insulin administration during cardiac surgery.

Methods

This open-label, Phase 1, single-center, dose-escalation clinical trial recruited patients scheduled to undergo elective cardiac surgery or major vascular surgery requiring cardiopulmonary bypass between February and September 2021. They were grouped into 5 dose-escalation cohorts and administered 0, 40, 80, 160, and 240 IU insulin (n = 6 in each group) via a metered nasal dispenser after the induction of general anesthesia. Blood samples were collected at 10-minute intervals for the first 60 minutes and at 30-minute intervals thereafter. Hypoglycemia was defined as a blood glucose level <70 mg/dL. Patient recruitment was terminated after hypoglycemia was observed in 2 patients in any of the groups.

Results

In total, 27 of 29 enrolled patients were administered intranasal insulin or saline. Hypoglycemia was not observed after the administration of intranasal insulin in the 0, 40, 80, or 160 IU groups; however, it was observed in 2 of 3 patients in the 240 IU group. The serum insulin concentration was elevated in the 160-IU group, but the C-peptide concentration was not elevated in any of the groups.

Conclusions

The administration of up to 160 IU intranasal insulin did not induce clinically significant hypoglycemia. However, 160 IU intranasal insulin should be administered cautiously because insulin can enter the systemic circulation in a dose-dependent manner.

Post-operative cognitive dysfunction is exacerbated by high-fat diet via TLR4 and prevented by dietary DHA supplementation

Post-operative cognitive dysfunction (POCD) is an abrupt decline in neurocognitive function arising shortly after surgery and persisting for weeks to months, increasing the risk of dementia diagnosis. Advanced age, obesity, and comorbidities linked to high-fat diet (HFD) consumption such as diabetes and hypertension have been identified as risk factors for POCD, although underlying mechanisms remain unclear. We have previously shown that surgery alone, or 3-days of HFD can each evoke sufficient neuroinflammation to cause memory deficits in aged, but not young rats. The aim of the present study was to determine if HFD consumption before surgery would potentiate and prolong the subsequent neuroinflammatory response and memory deficits, and if so, to determine the extent to which these effects depend on activation of the innate immune receptor TLR4, which both insults are known to stimulate. Young-adult (3mo) & aged (24mo) male F344xBN F1 rats were fed standard chow or HFD for 3-days immediately before sham surgery or laparotomy. In aged rats, the combination of HFD and surgery caused persistent deficits in contextual memory and cued-fear memory, though it was determined that HFD alone was sufficient to cause the long-lasting cued-fear memory deficits. In young adult rats, HFD + surgery caused only cued-fear memory deficits. Elevated proinflammatory gene expression in the hippocampus of both young and aged rats that received HFD + surgery persisted for at least 3-weeks after surgery. In a separate experiment, rats were administered the TLR4-specific antagonist, LPS-RS, immediately before HFD onset, which ameliorated the HFD + surgery-associated neuroinflammation and memory deficits. Similarly, dietary DHA supplementation for 4 weeks prior to HFD onset blunted the neuroinflammatory response to surgery and prevented development of persistent memory deficits. These results suggest that HFD 1) increases risk of persistent POCD-associated memory impairments following surgery in male rats in 2) a TLR4-dependent manner, which 3) can be targeted by DHA supplementation to mitigate development of persistent POCD.

Protective effect of intranasal insulin on postoperative cognitive dysfunction in elderly patients with metabolic syndrome undergoing noncardiac surgery: a randomized clinical trial

BACKGROUND

Insulin plays a crucial and multifactorial role in cognitive activity, with insulin resistance appearing in neurodegenerative and metabolic diseases. Insulin resistance contributes to the pathobiology of postoperative cognitive dysfunction (POCD) in experimental models, which can be rescued by intranasal insulin administration.

AIMS

To test the effect of intranasal insulin on the incidence of POCD in elderly patients with metabolic syndrome.

METHODS

The study was designed as a randomized, double-blind, placebo-controlled clinical trial. 116 elderly participants were randomly assigned to receive either 40 IU insulin (n = 58) or placebo (n = 58) for 7 days. The primary outcome was the incidence of POCD at 7 days and 3 months after surgery. Secondary outcomes included the degree of peripheral insulin resistance postoperatively, changes in peripheral inflammation levels and the safety of interventions.

RESULTS

The results showed that POCD occurred in the insulin group on the 7th postoperative day in 11 (20.8%) patients, which was fewer than the 23 (45.1%) patients in the placebo group (P = 0.008). The insulin group indicated better cognitive functional performance on language and memory test than the placebo group (P < 0.05). Mean peripheral plasma concentration of TNF-α (P < 0.05) and CRP (P < 0.001) in the insulin group was significantly declined compared with the placebo group on D3 and D7.

CONCLUSIONS

Intranasal insulin administration reduced the incidence of POCD and alleviated peripheral inflammatory levels in elderly patients with metabolic syndrome.

TRIAL REGISTRY

Chinese Clinical Trial Registry (ChiCTR1800015502).

Transversus thoracic muscle plane block for pain during cardiac surgery: a systematic review and meta-analysis

STUDY OBJECTIVE

The role of transversus thoracic muscle plane blocks (TTMPBs) during cardiac surgery is controversial. We conducted a systematic review to establish the effectiveness of this procedure.

DESIGN

Systematic review. We searched PubMed, Embase, Web of Science, CENTRAL, WanFang Data, and the China National Knowledge Infrastructure to June 2022, and followed the GRADE approach to evaluate the certainty of evidence.

STUDY ELIGIBILITY CRITERIA

Eligible studies enrolled adult patients scheduled to undergo cardiac surgery and randomized them to receive a TTMPB or no block/sham block.

MAIN RESULTS

Nine trials that enrolled 454 participants were included. Compared to no block/sham block, moderate certainty evidence found that TTMPB probably reduces postoperative pain at rest at 12 h [weighted mean difference (WMD) -1.51 cm on a 10 cm visual analogue scale for pain, 95% CI -2.02 to -1.00; risk difference (RD) for achieving mild pain or less (≤3 cm), 41%, 95% CI 17-65) and 24 h (WMD -1.07 cm, 95% CI -1.83 to -0.32; RD 26%, 95% CI 9-37). Moderate certainty evidence also supported that TTMPB probably reduces pain during movement at 12 h (WMD -3.42 cm, 95% CI -4.47 to -2.37; RD 46%, 95% CI 12-80) and at 24 h (WMD -1.73 cm, 95% CI -3.24 to -0.21; RD 32%, 95% CI 5-59), intraoperative opioid use [WMD -28 milligram morphine equivalent (MME), 95% CI -42 to -15], postoperative opioid consumption (WMD -17 MME, 95% CI -29 to -5), postoperative nausea and vomiting (absolute risk difference 255 less per 1000 persons, 95% CI 140-314), and intensive care unit (ICU) length of stay (WMD -13 h, 95% CI -21 to -6).

CONCLUSION

Moderate certainty evidence showed TTMPB during cardiac surgery probably reduces postoperative pain at rest and with movement, opioid consumption, ICU length of stay, and the incidence of nausea and vomiting.

Effect of transverse thoracic muscle plane block on postoperative cognitive dysfunction after open cardiac surgery: A randomized clinical trial

The transversus thoracis muscle plane (TTMP) block provides effective analgesia in cardiac surgery patients. The aim of this study was to assess whether bilateral TTMP blocks can reduce the incidence of postoperative cognitive dysfunction (POCD) in patients undergoing cardiac valve replacement. A group of 103 patients were randomly divided into the TTM group (n = 52) and the PLA (placebo) group (n = 51). The primary endpoint was the incidence of POCD at 1 week after surgery. Secondary outcome measures included a reduction of intraoperative mean arterial pressure (MAP) >20% from baseline, intraoperative and postoperative sufentanil consumption, length of stay in the ICU, incidence of postoperative nausea and vomiting (PONV), time to first faeces, postoperative pain at 24 h after surgery, time to extubation and the length of hospital stay. Interleukin (IL)-6, TNF-α, S-100β, insulin, glucose and insulin resistance were measured at before induction of anaesthesia, 1, 3and 7 days after surgery. The MoCA scores were significantly lower and the incidence of POCD decreased significantly in TTM group compared with PLA group at 7 days after surgery. Perioperative sufentanil consumption, the incidence of PONV and intraoperative MAP reduction >20% from baseline, length of stay in the ICU, postoperative pain at 24 h after surgery, time to extubation and the length of hospital stay were significantly decreased in the TTM group. Postoperatively, IL-6, TNF-α, S-100β, HOMA-IR, insulin, glucose levels increased and the TTM group had a lower degree than the PLA group at 1, 3 and 7 days after surgery. In summary, bilateral TTMP blocks could improve postoperative cognitive function in patients undergoing cardiac valve replacement.

Cognitive function and delirium following sevoflurane or propofol anesthesia for valve replacement surgery: A multicenter randomized controlled trial

Cognitive dysfunction is a common postoperative neurological complication in patients undergoing valve replacement surgery. This study aimed to compare the effects of sevoflurane versus propofol-based total intravenous anesthesia on the incidence of cognitive dysfunction following valve replacement surgery. This multicenter, randomized, controlled double-blinded study was conducted in three teaching hospitals in China. Patients receiving on-pump valve replacement surgery were enrolled. Stratified block randomization was used to randomly assign patients 1:1 to receive sevoflurane (1.0-1.5 MAC) or propofol (2.0-3.0 mg/kg/h) for anesthesia maintenance. The primary outcome was the incidence of cognitive dysfunction assessed by four cognitive tests before, as well as 7-14 days after surgery. Patients were randomly assigned to receive sevoflurane anesthesia (n = 144) or propofol-based total intravenous anesthesia (n = 145). The incidence of postoperative cognitive dysfunction in the sevoflurane anesthesia group (31.9%) was significantly lower than that in the total intravenous anesthesia group (43.4%; relative risk 0.61, 95% confidence interval [CI]: 0.38-0.97, p = 0.044). There was no difference in the incidence of delirium between patients receiving sevoflurane and total intravenous anesthesia (27.8% [35/144] vs. 25.9% [35/145], 1.10, 95% CI: 0.64 to 1.90, p = 0.736). There was a significant difference in the Katz Index on day 3 after surgery (3 [0.9) vs. 3 (1.0], 0.095, 95% CI: 0.05 to 0.43, p = 0.012). No difference was observed in other outcomes between the two groups. For patients undergoing on-pump valve replacement surgery, sevoflurane anesthesia had a smaller effect on cognitive function and independence in daily life activities compared with propofol anesthesia.

Insulin signaling in the central nervous system, a possible pathophysiological mechanism of anesthesia-induced delayed neurocognitive recovery/postoperative neurocognitive disorder: a narrative review

INTRODUCTION

Impairment in neurocognitive functions ranges between delayed neurocognitive recovery (DNR) and postoperative neurocognitive disorders (pNCD). Incidence varies from 11% after noncardiac surgery to 60% after cardiac surgery.

AREAS COVERED

Insulin receptors (IRs) signaling pathway in the central nervous system (CNS) could be a possible pathophysiological mechanism of anesthesia-induced DNR/pNCD and perioperative intranasal insulin administration could be a preventive approach. This hypothesis is supported by the following evidence: effects of IRs-CNS signaling pathway on neuromodulation; higher incidence of DNR/pNCD in patients with insulin resistance; neurotoxicity of IRs signaling pathways after anesthetic exposure; improvement of neurocognitive impairment after insulin exposure. This narrative review was conducted after a literature search of PubMed, EMBASE and SCOPUS online medical data performed in May 2022.

EXPERT OPINION

Perioperative intranasal insulin is shown to be protective and future studies should address: the role of insulin as a neuromodulator; its integration into neuroprotection approaches; patient populations that might benefit from this approach; a well-defined protocol of intranasal insulin administration in a perioperative background and other disciplines; and possible collateral effects.

Identification of individuals at risk for postoperative cognitive dysfunction (POCD)

Postoperative cognitive dysfunction (POCD) is common, occurring in around 10-54% of individuals within first few weeks after surgery. Although the majority of POCD is less commonly persistent later than 3 months following surgery, the condition increases length of stay (LOS), mortality and long-term cognitive decline, raising the need for a broad screening to identify individuals at risk for POCD during the perioperative period. In this narrative review, we summarize preoperative, intraoperative and postoperative risk factors for POCD reported in last 5 years and discuss neuropsychological tools and potential biomarkers and time points for assessment that might be suitable for clinical use. We aim to provide crucial information for developing a strategy of routine screening for POCD, which may assist with better identification of at-risk individuals for early interventions. Very importantly, the utilization of a standardized strategy may also allow higher consistency and comparability across different studies.

Is postoperative cognitive decline after cardiac surgery associated with plasma beta amyloid 1-42 levels?

Background

Postoperative cognitive decline following cardiac surgery is one of the frequently reported complications affecting postoperative outcome, characterized by impairment of memory or concentration. The aetiology is considered multifactorial and the research conducted so far has presented contradictory results. The proposed mechanisms to explain the cognitive decline associated with cardiac surgery include the neurotoxic accumulation of β-amyloid (Aβ) proteins similar to Alzheimer's disease. The comparison of coronary artery bypass grafting procedures concerning postoperative cognitive decline and plasmatic Aβ1-42 concentrations has not yet been conducted.

Methods

The research was designed as a controlled clinical study of patients with coronary artery disease undergoing surgical myocardial revascularization with or without the use of a cardiopulmonary bypass machine. All patients completed a battery of neuropsychological tests and plasmatic Aβ1-42 concentrations were collected.

Results

The neuropsychological test results postoperatively were significantly worse in the cardiopulmonary bypass group and the patients had larger shifts in the Aβ1-42 preoperative and postoperative values than the group in which off-pump coronary artery bypass was performed.

Conclusions

The conducted research confirmed the earlier suspected association of plasmatic Aβ1-42 concentration to postoperative cognitive decline and the results further showed that there were less changes and lower concentrations in the off-pump coronary artery bypass group, which correlated to less neurocognitive decline. There is a lot of clinical contribution acquired by this research, not only in everyday decision making and using amyloid proteins as biomarkers, but also in the development and application of non-pharmacological and pharmacological neuroprotective strategies.

Targeted temperature management in cardiac surgery: a systematic review and meta-analysis on postoperative cognitive outcomes

BACKGROUND

Postoperative cognitive decline occurs commonly after cardiac surgery. The available literature is inconclusive on the role of intraoperative causal or protective factors.

METHODS

We systematically reviewed studies evaluating delayed neurocognitive recovery (DNR), postoperative neurocognitive disorder (NCD), stroke, and the mortality rates among patients undergoing hypothermic or normothermic cardiopulmonary bypass (CPB). We further performed a subgroup analysis for age, surgery type (coronary artery bypass grafting [CABG], valve surgery, or combined), and the mean arterial blood pressure (MAP) during CPB, and conducted a proportion meta-analysis after calculation of single proportions and confidence intervals (CIs).

RESULTS

We included a total of 58 studies with 9609 patients in our analysis. Among these, 1906 of 4010 patients (47.5%) had DNR, and 2071 of 7160 (28.9%) had postoperative NCD. Ninety of 4625 patients (2.0%) had a stroke, and 174 of 7589 (2.3%) died. There was no statistically significant relationship between the considered variables and DNR, NCD, stroke, and mortality. In the subgroup analysis comparing hypothermic with normothermic CPB, we found higher NCD rates after combined surgery; for normothermic CPB cases only, the rates of DNR and NCD were lower after combined surgery compared with CABG surgery. A MAP >70 mm Hg compared with MAP=50-70 mm Hg during CPB was associated with a lower rate of DNR.

CONCLUSIONS

Temperature, MAP during cardiopulmonary bypass age, and surgery type were not associated with neurocognitive disorders, stroke, and mortality in cardiac surgery. Normothermic cardiopulmonary bypass, particularly when performed with MAP >70 mm Hg, may reduce the risk of postoperative neurocognitive decline after cardiac surgery.

PROSPERO REGISTRATION NUMBER

CRD42019140844.

Predictors of cognitive dysfunction after cardiac surgery: a systematic review

AIMS

Postoperative cognitive dysfunction (POCD) is often experienced by cardiac surgery patients; however, it is not known if some groups of patients experience this more frequently or severely than others.The aim of this systematic review was to identify preoperative and postoperative predictors of cognitive dysfunction in adults following cardiac surgery.

METHODS AND RESULTS

Eight bibliographic databases were searched (January 2005 to March 2021) in relation to cardiac surgery and cognition. Studies including adult patients who had undergone open cardiac surgery and using a validated measurement of cognitive function were included. Full-text review for inclusion, quality assessment, and data extraction were undertaken independently by two authors.A total of 2870 papers were identified, of which 36 papers met the inclusion criteria and were included in the review. The majority were prospective observational studies [n = 28 (75.7%)]. In total, 61 independent predictors (45 preoperative and 16 postoperative) were identified as significant in at least one study; advancing age and education level appear important. Age has emerged as the most common predictor of cognitive outcome.

CONCLUSION

Although a number of predictors of POCD have been identified, they have inconsistently been reported as significantly affecting cognitive outcome. Consistent with previous research, our findings indicate that older patients and those with lower educational levels should be prioritized when developing and trialling interventions to improve cognitive function. These findings are less than surprising if we consider the methodological shortcomings of included studies. It is evident that further high-quality research exploring predictors of POCD is required.

METTL3 regulates hippocampal gene transcription via N6-methyladenosine methylation in sevoflurane-induced postoperative cognitive dysfunction mouse

Elderly patients are prone to cognitive impairment and memory loss after surgical operations. This perioperative cerebral damage, named postoperative cognitive dysfunction (POCD), is profoundly affected by anesthesia. N6-methyladenosine (m6A) RNA methylation is a widely-studied epigenetic modification to regulate gene expression; however, is has never been studied in POCD. In the present study, elderly POCD mouse models were constructed using sevoflurane, and we observed a compromised global m6A RNA methylation in the mice’s hippocampuses compared with the control. Our RIP-Seq data suggested that 1244 genes (SOX2, SYN1, and BDNF) showed m6A RNA methylation in their 5′UTRs, which was significantly lower than that in the control; while only 56 genes (BACE1 and IL17A) showed m6A RNA methylation in their 5′UTRs, which was significantly higher than that in the control. Unexpectedly, m6A RNA methylation with significant differences in exons, introns, or 3′UTRs was observed in only few genes. Although we failed to find any differences in the expression of m6A-associated proteins, such as m6A “writers”, “erasers”, and “readers”, between the sevoflurane treatment and control groups, RIP-qPCR assays indicated that the binding affinity of METTL3 on mRNA 5′UTRs was particularly weakened in target genes by sevoflurane. Finally, we found that phosphorylation of METTL3 could be reduced by sevoflurane because of the inactivation of the MAPK/ERK pathway. Overall, our study determined that the inactivation of METTL3 in the mouse hippocampus, induced by sevoflurane-mediated MAPK/ERK suppression in vivo, resulted in a perturbation in m6A RNA methylation signals in the pathogenesis of POCD.

Amelioration of Hippocampal Insulin Resistance Reduces Tau Hyperphosphorylation and Cognitive Decline Induced by Isoflurane in Mice

General anesthetics can induce cognitive impairments and increase the risk of Alzheimer’s disease (AD). However, the underlying mechanisms are still unknown. Our previous studies shown that long-term isoflurane exposure induced peripheral and central insulin resistance (IR) in adult mice and aggravated IR in type 2 diabetes mellitus (T2DM) mice. Clinical and preclinical studies revealed an association between impaired insulin signaling and tau pathology in AD and other tauopathies. We investigated if alleviation of hippocampal IR by the antidiabetic agent metformin could reduce tau hyperphosphorylation and cognitive decline induced by isoflurane in mice. The effects of prolonged (6 h) isoflurane anesthesia on hippocampal IR, hippocampal tau hyperphosphorylation, and hippocampus-dependent cognitive function were evaluated in wild type (WT) adult mice and the high-fat diet plus streptozotocin (HFD/STZ) mouse model of T2DM. Here we shown that isoflurane and HFD/STZ dramatically and synergistically induced hippocampal IR and fear memory impairment. Metformin pretreatment strongly ameliorated hippocampal IR and cognitive dysfunction caused by isoflurane in WT mice, but was less effective in T2DM mice. Isoflurane also induced hippocampal tau hyperphosphorylation and metformin reversed this effect. In addition, isoflurane significantly increased blood glucose levels in both adult and T2DM mice, and metformin reversed this effect as well. Administration of 25% glucose to metformin-pretreated mice induced hyperglycemia, but surprisingly did not reverse the benefits of metformin on hippocampal insulin signaling and fear memory following isoflurane anesthesia. Our findings show hippocampal IR and tau hyperphosphorylation contribute to acute isoflurane-induced cognitive dysfunction. Brief metformin treatment can mitigate these effects through a mechanism independent of glycemic control. Future studies are needed to investigate whether long-term metformin treatment can also prevent T2DM-induced hippocampal IR and cognitive decline.

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

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

Intranasal administration of 40 and 80 units of insulin does not cause hypoglycemia during cardiac surgery: a randomized controlled trial

PURPOSE

Intranasal insulin administration may improve cognitive function in patients with dementia and may prevent cognitive problems after surgery. Although the metabolic effects of intranasal insulin in non-surgical patients have been studied, its influence on glucose concentration during surgery is unknown.

METHODS

We conducted a randomized, double-blind, placebo-contolled trial in patients scheduled for elective cardiac surgery. Patients with type 2 diabetes mellitus (T2DM) and non-T2DM patients were randomly allocated to one of three groups (normal saline, 40 international units [IU] of intranasal insulin, and 80 IU intranasal insulin). Insulin was given after the induction of general anesthesia. Glucose and plasma insulin concentrations were measured in ten-minute intervals during the first hour and every 30 min thereafter. The primary outcome was the change in glucose concentration 30 min after intranasal insulin administration.

RESULTS

A total of 115 patients were studied, 43 of whom had T2DM. In non-T2DM patients, 40 IU intranasal insulin did not affect glucose concentration, while 80 IU intranasal insulin led to a statistically significant but not clinically important decrease in blood glucose levels (mean difference, 0.4 mMol·L^-1; 95% confidence interval, 0.1 to 0.7). In T2DM patients, neither 40 IU nor 80 IU of insulin affected glucose concentration. No hypoglycemia (< 4.0 mMol·L^-1) was observed after intranasal insulin administration in any patients. In non-T2DM patients, changes in plasma insulin were similar in the three groups. In T2DM patients, there was an increase in plasma insulin concentrations ten minutes after administration of 80 IU of intranasal insulin compared with saline.

CONCLUSIONS

In patients with and without T2DM undergoing elective cardiac surgery, intranasal insulin administration at doses as high as 80 IU did not cause clinically important hypoglycemia.

TRIAL REGISTRATION

www.ClinicalTrials.gov (NCT02729064); registered 5 April 2016.

Changes in the concentrations of mediators in exhaled breath condensate during cardiac valve replacement under cardiopulmonary bypass and their relations with postoperative acute respiratory distress syndrome

To investigate the changes in the concentrations of interleukin-6 (IL-6), interleukin-8 (IL-8), tumor necrosis factor-α (TNF-α), and 8-iso-prostaglandin F2α (8-isoPGF2α) in exhaled breath condensate (EBC) in patients undergoing cardiac valve replacement under cardiopulmonary bypass (CPB) and its relationship with postoperative acute respiratory distress syndrome (ARDS).A prospective, case-control study was performed on 55 patients undergoing elective cardiac valve replacement under cardiopulmonary bypass, between November 2017 and May 2019. According to the diagnosis of postoperative ARDS, the patients were divided into ARDS group and control group. We compared the clinical characteristics, outcomes, respiratory mechanics, oxygenation parameters, and mediators in the 2 groups immediately after tracheal intubation (T1), at the end of CPB (T2), and 2 hours (T3) and 6 hours (T4) after CPB, and calculated the receiver operating characteristic curve (ROC), sensitivity, and specificity of the corresponding mediators.ARDS occurred in 29 patients after CPB. The ARDS group exhibited prolonged postoperative ventilator support, time to extubation, length of stay in the ICU, and postoperative length of stay. The peak airway pressure (Ppeak) and plat airway pressure (Pplat) at T4 were higher in the ARDS group compared with the control group. The alveolar-arterial oxygen partial pressure [P(A-a)O2] and respiratory index (RI) were higher and PaO2/FiO2 was lower in the ARDS group at T2-4 compared with the control group. The levels of EBC and serum mediators in the ARDS group were significantly higher at T2-4 compared with those in the control group. All the mediators in EBC were correlated significantly with those in the serum in the ARDS group (r = 0.7314, 0.898, 0.8386, 0.792) and control group (r = 0.6093, 0.8524, r = 0.7828, r = 0.6575) (P < .001). Meanwhile, the area under the curve (AUC) of IL-8 in EBC was significantly lower at T2 and the AUC of IL-6 in EBC was significantly higher at T4 than in serum (P < .05). In addition, all of the mediators in EBC had a certain accuracy in diagnose of postoperative ARDS.EBC analysis could be used to predict the high incidence of ARDS after cardiac valve replacement under CPB.

Anesthesiology and cognitive impairment: a narrative review of current clinical literature

Background

The impact of general anesthesia on cognitive impairment is controversial and complex. A large body of evidence supports the association between exposure to surgery under general anesthesia and development of delayed neurocognitive recovery in a subset of patients. Existing literature continues to debate whether these short-term effects on cognition can be attributed to anesthetic agents themselves, or whether other variables are causative of the observed changes in cognition. Furthermore, there is conflicting data on the relationship between anesthesia exposure and the development of long-term neurocognitive disorders, or development of incident dementia in the patient population with normal preoperative cognitive function. Patients with pre-existing cognitive impairment present a unique set of anesthetic considerations, including potential medication interactions, challenges with cooperation during assessment and non-general anesthesia techniques, and the possibility that pre-existing cognitive impairment may impart a susceptibility to further cognitive dysfunction.

Main body

This review highlights landmark and recent studies in the field, and explores potential mechanisms involved in perioperative cognitive disorders (also known as postoperative cognitive dysfunction, POCD). Specifically, we will review clinical and preclinical evidence which implicates alterations to tau protein, inflammation, calcium dysregulation, and mitochondrial dysfunction. As our population ages and the prevalence of Alzheimer’s disease and other forms of dementia continues to increase, we require a greater understanding of potential modifiable factors that impact perioperative cognitive impairment.

Conclusions

Future research should aim to further characterize the associated risk factors and determine whether certain anesthetic approaches or other interventions may lower the potential risk which may be conferred by anesthesia and/or surgery in susceptible individuals.

Postoperative Cognitive Decline After Cardiac Surgery: A Narrative Review of Current Knowledge in 2019

The growing number of publications concerning postoperative cognitive decline (POCD) after cardiac surgery is indicative of the health-related and economic-related importance of this intriguing issue. Significantly, the reported POCD incidence over the years has remained steady due to various unresolved challenges regarding the examination of this multidisciplinary topic. In particular, a universally accepted POCD definition has not been established, and the pathogenesis is still vaguely understood. However, numerous recent studies have focused on the role of the inflammatory response to a surgical procedure in POCD occurrence. Therefore, this traditional narrative review summarizes and evaluates the latest findings, with special attention paid to the difficulties of defining POCD as well as the involvement of inflammation in POCD development. We searched the MEDLINE, Scopus, PsycINFO and CENTRAL databases for the best evidence, which was classified according to the Oxford Centre for Evidence-based Medicine. To our knowledge, this is the first narrative review that identified class-1 evidence (systematic review of randomized trials), although most evidence is still at class-2 or below. Furthermore, we revealed that defining POCD is a very controversial matter and that the inflammatory response plays an important role in the mutually overlapping processes included in POCD development. Thus, developing the definition of POCD represents an absolute priority in POCD investigations, and the inflammatory response to cardiac surgery merits further research.

Effects of Isolated Impaired Fasting Glucose on Brain Injury During Cardiac Surgery Under Cardiopulmonary Bypass

Objective: To evaluate the effects of isolated impaired fasting glucose (IIFG) on brain injury in patients undergoing cardiopulmonary bypass (CPB) surgery. Methods: Patients with rheumatic heart valve disease who underwent elective mitral valve replacement were included and divided into control and IIFG groups. Pre-, intra-, and postoperative blood glucose levels, serum insulin levels, insulin resistance index (HOMA-IR), lactic acid levels, and neuron-specific enolase (NSE) and S100B levels were measured. The cerebral oxygen extraction ratio (OER) was calculated. Cognitive function was assessed via the Mini-Mental State Examination (MMSE). Results: HOMA-IR levels were higher in the IIFG group than the control group 30 min after the beginning of CPB, at the termination of CPB, and 2 h after the termination of CPB. Cerebral OER and lactic acid increased intraoperatively in both groups, especially in the IIFG group. NSE and S100B levels were higher in the IIFG group than in the control group at the termination of CPB, 2 h after the termination of CPB, and at 24 h postoperatively. The MMSE scores did not significantly differ between the two groups. Delirium occurred in two patients in the IIFG group, and one in the control group. No other signs and symptoms of brain injuries were detected in either group. Conclusions: The increased postoperative NSE and S100B levels in the IIFG group compared with controls may be associated with severe insulin resistance and stress hyperglycemia. However, the IIFG group did not have clinical manifestations of brain injuries, including cognitive impairment.

Neutralizing IL-6 reduces heart injury by decreasing nerve growth factor precursor in the heart and hypothalamus during rat cardiopulmonary bypass

AIMS

To investigate whether the expression of nerve growth factor precursor (proNGF) changes during cardiopulmonary bypass (CPB) and whether neutralizing interleukin-6 (IL-6) during CPB has cardiac benefits.

MAIN METHODS

Thirty patients undergoing CPB were recruited and their serum proNGF and troponin-I (TNI) were detected. In addition, rats were divided into three groups: CPB group, CPB with cardiac ischemia-reperfusion (IR) group, and a control group. The pre-CPB standard deviation of N-N intervals (SDNN) and post-CPB SDNN were compared. At the end of CPB, nerve peptide Y (NPY), acetylcholinesterase, cell apoptosis, and proNGF protein expression were measured in the heart and hypothalamus. Another rat cohort undergoing CPB was divided into two groups: an anti-IL-6 group with IL-6 antibody and a control group with phosphate buffer solution. At the end of CPB, serum hs-troponin-T and cardiac caspases 3 and 9 were detected. NPY and proNGF in the heart and hypothalamus were detected.

KEY FINDINGS

In patients, serum proNGF increased during CPB, and the concentration was positively correlated with TNI. In rats, cardiac autonomic nervous function was disturbed during CPB. More apoptotic cells and higher levels of proNGF were found in the heart and hypothalamus in the CPB groups than in the control groups. Neutralizing IL-6 was beneficial to lower cardiac injury by decreasing proNGF and apoptosis.

SIGNIFICANCE

CPB induced changes in proNGF in the heart and hypothalamus. Suppressing inflammation attenuated myocardial apoptosis and autonomic nerve function disturbance in CPB rats, likely due in part to regulation of proNGF in the heart and hypothalamus.