AChE-activity in critically ill patients with suspected septic encephalopathy: a prospective, single-centre study

Therapeutic effects of orexin-A in sepsis-associated encephalopathy in mice

BACKGROUND

Sepsis-associated encephalopathy (SAE) causes acute and long-term cognitive deficits. However, information on the prevention and treatment of cognitive dysfunction after sepsis is limited. The neuropeptide orexin-A (OXA) has been shown to play a protective role against neurological diseases by modulating the inflammatory response through the activation of OXR1 and OXR2 receptors. However, the role of OXA in mediating the neuroprotective effects of SAE has not yet been reported.

METHODS

A mouse model of SAE was induced using cecal ligation perforation (CLP) and treated via intranasal administration of exogenous OXA after surgery. Mouse survival, in addition to cognitive and anxiety behaviors, were assessed. Changes in neurons, cerebral edema, blood-brain barrier (BBB) permeability, and brain ultrastructure were monitored. Levels of pro-inflammatory factors (IL-1β, TNF-α) and microglial activation were also measured. The underlying molecular mechanisms were investigated by proteomics analysis and western blotting.

RESULTS

Intranasal OXA treatment reduced mortality, ameliorated cognitive and emotional deficits, and attenuated cerebral edema, BBB disruption, and ultrastructural brain damage in mice. In addition, OXA significantly reduced the expression of the pro-inflammatory factors IL-1β and TNF-α, and inhibited microglial activation. In addition, OXA downregulated the expression of the Rras and RAS proteins, and reduced the phosphorylation of P-38 and JNK, thus inhibiting activation of the MAPK pathway. JNJ-10,397,049 (an OXR2 blocker) reversed the effect of OXA, whereas SB-334,867 (an OXR1 blocker) did not.

CONCLUSION

This study demonstrated that the intranasal administration of moderate amounts of OXA protects the BBB and inhibits the activation of the OXR2/RAS/MAPK pathway to attenuate the outcome of SAE, suggesting that OXA may be a promising therapeutic approach for the management of SAE.

Cholinesterase activities and sepsis-associated encephalopathy in viral versus nonviral sepsis

PURPOSE

There is evidence that cholinergic imbalance secondary to neuroinflammation plays a role in the pathophysiology of sepsis-associated encephalopathy (SAE). Blood acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activities have been proposed as surrogate parameters for the cholinergic function of the central nervous system. Viral sepsis is associated with systemic inflammation and BChE has been reported to be of prognostic value in a small cohort of COVID-19 patients. Nevertheless, the prognostic value of AChE in patients with viral sepsis remains unclear.

METHODS

We investigated the role of AChE and BChE activities as prognostic biomarkers of SAE and mortality in patients with viral vs nonviral sepsis enrolled in two prospective cohort studies. We quantified the AChE and BChE activities in whole blood of patients at two time points in the acute phase of viral sepsis (N = 108) and compared them with the activities in patients with nonviral sepsis (N = 117) and healthy volunteers (N = 81). Patients were observed until discharge from the intensive care unit (ICU).

RESULTS

Three days after sepsis onset, the median [interquartile range] levels of AChE and BChE were reduced in both patients with viral sepsis (AChE, 5,105 [4,010-6,250] U·L-1; BChE, 1,943 [1,393-2,468] U·L-1) and nonviral sepsis (AChE, 4,424 [3,630-5,055] U·L-1; BChE, 1,095 [834-1,526] U·L-1) compared with healthy volunteers (AChE, 6,693 [5,401-8,020] U·L-1; BChE, 2,645 [2,198-3,478] U·L-1). Patients with viral sepsis with SAE during their ICU stay had lower AChE activity three days after sepsis onset than patients without SAE (4,249 [3,798-5,351] U·L-1 vs 5,544 [4,124-6,461] U·L-1). Butyrylcholinesterase activity seven days after sepsis onset was lower in patients with viral sepsis who died in the ICU than in surviving patients (1,427 [865-2,181] U·L-1 vs 2,122 [1,571-2,787] U·L-1).

CONCLUSION

Cholinesterase activities may be relevant prognostic markers for the occurrence of SAE and mortality in the ICU in patients with viral sepsis.

STUDY REGISTRATION

This study constitutes an analysis of data from the ongoing studies ICROS (NCT03620409, first submitted 15 May 2018) and ICROVID (DRKS00024162, first submitted 9 February 2021).

The role of the peripheral system dysfunction in the pathogenesis of sepsis-associated encephalopathy

Sepsis is a condition that greatly impacts the brain, leading to neurological dysfunction and heightened mortality rates, making it one of the primary organs affected. Injury to the central nervous system can be attributed to dysfunction of various organs throughout the entire body and imbalances within the peripheral immune system. Furthermore, central nervous system injury can create a vicious circle with infection-induced peripheral immune disorders. We collate the pathogenesis of septic encephalopathy, which involves microglial activation, programmed cell death, mitochondrial dysfunction, endoplasmic reticulum stress, neurotransmitter imbalance, and blood-brain barrier disruption. We also spotlight the effects of intestinal flora and its metabolites, enterocyte-derived exosomes, cholinergic anti-inflammatory pathway, peripheral T cells and their cytokines on septic encephalopathy.

Potentials of Acetylcholinesterase and Butyrylcholinesterase Alterations in On-Pump Coronary Artery Bypass Surgery in Postoperative Delirium: An Observational Trial

Cardiac surgery is regularly associated with postoperative delirium (POD), affected by neuro-inflammation and changes in cholinergic activity. Therefore, this prospective observational study aimed to evaluate whether pre- and perioperative changes in blood acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activity were associated with POD development in patients undergoing isolated elective coronary artery bypass graft (CABG) surgery. It included 93 patients. Pre- and postoperative blood AChE and BChE activities were measured with photometric rapid-point-of-care-testing. The Intensive Care Delirium Screening Checklist and the Confusion Assessment Method for the Intensive Care Unit were used to screen patients for POD. POD developed in 20 patients (21.5%), who were older (p = 0.003), had higher EuroSCOREs (p ≤ 0.001), and had longer intensive care unit stays (p < 0.001). On postoperative day one, BChE activity decreased from preoperative values more in patients with (31.9%) than without (23.7%) POD (group difference p = 0.002). Applying a cutoff of ≥32.0% for BChE activity changes, receiver operating characteristic analysis demonstrated a moderate prediction capability for POD (area under the curve = 0.72, p = 0.002). The risk of developing POD was 4.31 times higher with a BChE activity change of ≥32.0% (p = 0.010). Monitoring the pre- to postoperative reduction in BChE activity might be a clinically practicable biomarker for detecting patients at risk of developing POD after CABG surgery.

Non-Neuronal Acetylcholinesterase Activity Shows Limited Utility for Early Detection of Sepsis

(1) Background: Sepsis is a severe systemic inflammatory condition characterized by rapid clinical deterioration and organ dysfunction. The cholinergic system has been implicated in modulating the inflammatory response. Acetylcholinesterase (AChE), an enzyme primarily responsible for the hydrolysis of acetylcholine, has been proposed as a potential early indicator of sepsis onset. However, the exact role of non-neuronal AChE activity in sepsis and its correlation with disease severity and patient outcomes remain unclear. This study aimed to investigate the involvement of AChE activity in sepsis and evaluate its association with disease severity and clinical outcomes. (2) Methods: A prospective study included 43 septic patients. AChE activity was measured at sepsis detection, as well as 7 and 28 days later. Inflammatory biomarkers, disease severity scores, and patient outcomes were evaluated. (3) Results: AChE activity remained stable for 7 days and decreased at 28 days. However, there was no correlation between initial AChE activity and inflammatory biomarkers, disease severity scores, ICU stay, or hospital stay. (4) Conclusions: Non-neuronal AChE activity may not reliably indicate early sepsis or predict disease severity.

Resveratrol glycoside mediates microglial endoplasmic reticulum stress to mitigate LPS-induced sepsis-associated cognitive dysfunction

BACKGROUND

As a common complication of sepsis, sepsis-associated encephalopathy (SAE) is characterized by diffuse brain dysfunction and neurological damage and closely associated with long-term cognitive dysfunction. The dysregulated host response triggered by neurotoxicity of microglia is an important cause of diffuse brain dysfunction in SAE. Resveratrol glycoside has anti-inflammatory and antioxidant effects. However, there is no evidence whether resveratrol glycoside could alleviate SAE.

METHODS

LPS administration was used to induce SAE in mice. Step-down test (SDT) and Morris water maze test (MWM) were performed to evaluate the cognitive function of mice with SAE. Western blot and immunofluorescence were used to reveal the endoplasmic reticulum stress (ERS) regulation. Microglia cell line BV-2 was used to validate the effect of resveratrol glycoside on LPS-stimulated ERS in vitro.

RESULTS

Compared with the control group, LPS-stimulated mice had decreased cognitive function, but this phenomenon was well reversed by resveratrol glycoside administration, in which the SDT assay showed longer retention time, both in short-term memory (STM) and long-term memory (LTM). Western blot indicated that the expression of ER stress-related protein PERK/CHOP in LPS-stimulated mice were significantly increased, while that in the resveratrol glycoside-treated group were relieved. Furthermore, Immunofluorescence revealed resveratrol glycoside mainly worked on microglia in mediating the ER stress, in which the expression of PERK/CHOP were significantly inhibited in resveratrol glycoside group mice. In vitro, BV2 showed consistent results with the aforementioned.

CONCLUSION

Resveratrol glycoside could alleviate the cognitive dysfunction caused by LPS-induced SAE, mainly by inhibiting the ER stress and maintaining the homeostasis of ER function of microglia.

Neurochemical effects of sepsis on the brain

Sepsis is a life-threatening organ dysfunction triggered by a dysregulated host immune response to eliminate an infection. After the host immune response is activated, a complex, dynamic, and time-dependent process is triggered. This process promotes the production of inflammatory mediators, including acute-phase proteins, complement system proteins, cytokines, chemokines, and antimicrobial peptides, which are required to initiate an inflammatory environment for eliminating the invading pathogen. The physiological response of this sepsis-induced systemic inflammation can affect blood-brain barrier (BBB) function; subsequently, endothelial cells produce inflammatory mediators, including cytokines, chemokines, and matrix metalloproteinases (MMPs) that degrade tight junction (TJ) proteins and decrease BBB function. The resulting BBB permeability allows peripheral immune cells from the bloodstream to enter the brain, which then release a range of inflammatory mediators and activate glial cells. The activated microglia and astrocytes release reactive oxygen species (ROS), cytokines, chemokines, and neurochemicals, initiate mitochondrial dysfunction and neuronal damage, and exacerbate the inflammatory milieu in the brain. These changes trigger sepsis-associated encephalopathy (SAE), which has the potential to increase cognitive deterioration and susceptibility to cognitive decline later in life.

In a secondary analysis from a randomised, double-blind placebo-controlled trial Dexmedetomidine blocks cholinergic dysregulation in delirium pathogenesis in patients with major surgery

Dexmedetomidine is an alpha-2 adrenoreceptor agonist with anti-inflammatory and anti-delirogenic properties. Pathogenesis of postoperative delirium (POD) includes cholinergic dysfunction and deregulated inflammatory response to surgical trauma. Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) are discussed as biomarkers for both POD and severity in acute inflammation. To show whether there is a link between blood cholinesterase activities and dexmedetomidine, we performed a secondary analysis of a randomised, double-blind, placebo-controlled trial that recently showed a lower incidence of POD in the dexmedetomidine group. Abdominal or cardiac surgical patients aged ≥ 60 years were randomised to receive dexmedetomidine or placebo intra- and postoperatively in addition to standard general anaesthesia. We analysed the course of perioperative cholinesterase activities of 56 patients, measured preoperatively and twice postoperatively. Dexmedetomidine resulted in no change in AChE activity and caused a rapid recovery of BChE activity after an initial decrease, while placebo showed a significant decrease in both cholinesterase activities. There were no significant between-group differences at any point in time. From these data it can be assumed that dexmedetomidine could alleviate POD via altering the cholinergic anti-inflammatory pathway (CAIP). We advocate for further investigations to show the direct connection between dexmedetomidine and cholinesterase activity.

Paediatric sepsis-associated encephalopathy (SAE): a comprehensive review

Sepsis-associated encephalopathy (SAE) is one of the most common types of organ dysfunction without overt central nervous system (CNS) infection. It is associated with higher mortality, low quality of life, and long-term neurological sequelae, its mortality in patients diagnosed with sepsis, progressing to SAE, is 9% to 76%. The pathophysiology of SAE is still unknown, but its mechanisms are well elaborated, including oxidative stress, increased cytokines and proinflammatory factors levels, disturbances in the cerebral circulation, changes in blood-brain barrier permeability, injury to the brain's vascular endothelium, altered levels of neurotransmitters, changes in amino acid levels, dysfunction of cerebral microvascular cells, mitochondria dysfunction, activation of microglia and astrocytes, and neuronal death. The diagnosis of SAE involves excluding direct CNS infection or other types of encephalopathies, which might hinder its early detection and appropriate implementation of management protocols, especially in paediatric patients where only a few cases have been reported in the literature. The most commonly applied diagnostic tools include electroencephalography, neurological imaging, and biomarker detection. SAE treatment mainly focuses on managing underlying conditions and using antibiotics and supportive therapy. In contrast, sedative medication is used judiciously to treat those showing features such as agitation. The most widely used medication is dexmedetomidine which is neuroprotective by inhibiting neuronal apoptosis and reducing a sepsis-associated inflammatory response, resulting in improved short-term mortality and shorter time on a ventilator. Other agents, such as dexamethasone, melatonin, and magnesium, are also being explored in vivo and ex vivo with encouraging results. Managing modifiable factors associated with SAE is crucial in improving generalised neurological outcomes. From those mentioned above, there are still only a few experimentation models of paediatric SAE and its treatment strategies. Extrapolation of adult SAE models is challenging because of the evolving brain and technical complexity of the model being investigated. Here, we reviewed the current understanding of paediatric SAE, its pathophysiological mechanisms, diagnostic methods, therapeutic interventions, and potential emerging neuroprotective agents.

Increased Enzymatic Activity of Acetylcholinesterase Indicates the Severity of the Sterile Inflammation and Predicts Patient Outcome following Traumatic Injury

Traumatic injury induces sterile inflammation, an immune response often associated with severe organ dysfunction. The cholinergic system acts as an anti-inflammatory in injured patients. Acetylcholinesterase (AChE), an enzyme responsible for the hydrolysis of acetylcholine, plays an essential role in controlling cholinergic activity. We hypothesized that a change in the AChE activity might indicate the severity of the traumatic injury. This study included 82 injured patients with an Injury Severity Score (ISS) of 4 or above and 40 individuals without injuries. Bedside-measured AChE was obtained on hospital arrival, followed by a second measurement 4-12 h later. C-reactive protein (CRP), white blood cell count (WBCC), and Sequential Organ Failure Assessment (SOFA) score were simultaneously collected. Injured patients showed an early and sustained increase in AChE activity. CRP remained unaffected at hospital admission and increased subsequently. Initially elevated WBCC recovered 4-12 h later. AChE activity directly correlated with the ISS and SOFA scores and predicted the length of ICU stay when measured at hospital admission. An early and sustained increase in AChE activity correlated with the injury severity and could predict the length of ICU stay in injured patients, rendering this assay a complementary diagnostic and prognostic tool at the hand of the attending clinician in the emergency unit.

Secukinumab alleviates cognitive impairment by attenuating oxidative stress and neuronal apoptosis via the IL-17RA/AKT/ERK1/2 pathway in a rat model of sepsis

BACKGROUND

Septic-associated encephalopathy (SAE) is a critical manifestation of sepsis that leads to long-term cognitive impairment. Interleukin (IL)-17A has been shown to mediate neuronal apoptosis in central nervous system diseases, while oxidative stress has been found to have a detrimental effect in SAE. However, the relationship between IL-17A and oxidative stress in SAE remains unclear. This study aimed to investigate the effects of secukinumab on alleviating cognitive impairment in a rat model of sepsis, as well as examine its underlying molecular mechanism of action.

METHODS

A total of 282 male 8-week-old Sprague-Dawley rats were randomly subjected to cecal ligation and puncture (CLP) or sham treatment followed by volume resuscitation immediately after surgery. Secukinumab was administered intranasally 1 h post-CLP. Rats were given the p-ERK activator ceramide C6 intracerebroventricularly (i.c.v) 24 h before CLP surgery. Recombinant rIL-17A was administered i.c.v. at 0 h in naive rats, followed by intraperitoneal injection of the AKT inhibitor GDC0068 1 h post-rIL-17A injection. Clinical scores, body weight, and survival rate were assessed. In addition, immunofluorescence staining, neurobehavioral tests, Nissl staining, and western blotting were performed. Cognitive function was assessed 15-20 days post-CLP using the Morris water maze test.

RESULTS

IL-17A and IL-17RA protein expression levels in the rat hippocampus increased and peaked 24 h post-CLP. Furthermore, IL-17RA was found to be expressed in neurons. The survival rate after CLP was 50%. Following CLP, an increased clinical score and significant decrease in body weight were observed. However, treatment with secukinumab led to a decrease in the clinical score of rats 24 h post-CLP. CLP resulted in spatial and memory impairment and anxiety-like behaviors in rats, while secukinumab treatment significantly alleviated cognitive impairment compared to the CLP group (p < 0.05). In addition, oxidative stress and neuronal apoptosis were found to be increased in the CLP group, while secukinumab significantly reduced oxidative stress and neuronal apoptosis in the hippocampus following CLP. Furthermore, secukinumab treatment led to a significant decrease in the protein expression levels of p-AKT, p-ERK1/2, Romo1, and Bax, together with increased Bcl-2 protein expression. Finally, treatment with ceramide C6 and GDC0068 abolished the neuroprotective effects of secukinumab post-CLP.

CONCLUSION

Our results demonstrated that secukinumab attenuated oxidative stress and neuronal apoptosis and partially ameliorated cognitive impairment via the IL-17RA/AKT/ERK1/2 pathway in a rat model of sepsis. Thus, secukinumab may be a potential therapeutic strategy for septic patients.

Current Understanding of Long-Term Cognitive Impairment After Sepsis

Sepsis is recognized as a life-threatening multi-organ dysfunction resulting from a dysregulated host response to infection. Although the incidence and mortality of sepsis decrease significantly due to timely implementation of anti-infective and support therapies, accumulating evidence suggests that a great proportion of survivors suffer from long-term cognitive impairment after hospital discharge, leading to decreased life quality and substantial caregiving burdens for family members. Several mechanisms have been proposed for long-term cognitive impairment after sepsis, which are not mutually exclusive, including blood-brain barrier disruption, neuroinflammation, neurotransmitter dysfunction, and neuronal loss. Targeting these critical processes might be effective in preventing and treating long-term cognitive impairment. However, future in-depth studies are required to facilitate preventive and/or treatment strategies for long-term cognitive impairment after sepsis.

Oximes should be used routinely in organophosphate poisoning

In poisoning with organophosphorus compounds, patients can only profit from the regeneration of acetylcholinesterase, when the poison load has dropped below a toxic level. Every measure that allows an increase of synaptic AChE activity at the earliest is essential for timely termination of the cholinergic crisis. Only a drug induced reactivation allows to achieve fast restoration of the inhibited AChE. Obidoxime and pralidoxime have proved to be able to reactivate inhibited cholinesterase thereby saving life of poisoned animals. A plasma level of obidoxime or pralidoxime allowing reactivation in humans poisoned by OP can be adjusted. There is no doubt that obidoxime and pralidoxime are able to reactivate OP inhibited AChE activity in poisoned patients thereby increasing AChE activity and contributing substantially to terminate cholinergic crisis. Hence, a benefit may be expected when substantial reactivation is achieved. A test system allowing determination of red blood cell AChE activity, reactivatability, inhibitory equivalents and BChE activity is available for relatively low cost. If any reactivation is possible while inhibiting equivalents are present, oxime therapy should be maintained. In particular, when balancing the benefit risk assessment, obidoxime or palidoxime should be given as soon as possible and as long as a substantial reactivation may be expected.

Prospective, observational, single-centre cohort study with an independent control group matched for age and sex aimed at investigating the significance of cholinergic activity in patients with schizophrenia: study protocol of the CLASH-study

INTRODUCTION

Alterations in the cholinergic metabolism may cause various clinical symptoms of schizophrenia. In addition to the 'monoamine hypothesis,' neuroinflammation is also discussed as a cause of schizophrenia. To date, there has been no evidence of alterations in the central cholinergic transmitter balance in patients with schizophrenia under clinical conditions. By contrast, studies in critically ill patients have established the measurement of acetylcholinesterase activity as a suitable surrogate parameter of central cholinergic transmitter balance/possible pathophysiological changes. Butyrylcholinesterase activity has been established as a parameter indicating possible (neuro)inflammatory processes. Both parameters can now be measured using a point-of-care approach. Therefore, the primary objective of this study is to investigate whether acetylcholinesterase and butyrylcholinesterase activity differs in patients with various forms of schizophrenia. Secondary objectives address the possible association between acetylcholinesterase and butyrylcholinesterase activity and (1) schizophrenic symptoms using the Positive and Negative Syndrome Scale, (2) the quantity of antipsychotics taken and (3) the duration of illness.

METHODS AND ANALYSIS

The study is designed as a prospective, observational cohort study with one independent control group. It is being carried out at the Department of Psychiatry and Psychotherapy III, Ulm University Hospital, Germany. Patient enrolment started in October 2020, and the anticipated end of the study is in January 2022. The enrolment period was set from October 2020 to December 2021 (extension required due to SARS-CoV-2 pandemic). The sample size is calculated at 50 patients in each group. Esterase activity is measured on hospital admission (acute symptomatology) and after referral to a postacute ward over a period of three consecutive days. The matched control group will be created after reaching 50 patients with schizophrenia. This will be followed by a comprehensive statistical analysis of the data set.

ETHICS AND DISSEMINATION

The study was registered prospectively in the German Clinical Trials Register (DRKS-ID: DRKS00023143,URL: https://www.drks.de/drks_web/navigate.do?navigationId=trial.HTML&TRIAL_ID=DRKS00023143) after approval by the ethics committee of the University of Ulm, Germany Trial Code No. 280/20.

TRIAL REGISTRATION NUMBER

DRKS00023143; Pre-results.