Sepsis-Associated Brain Dysfunction: A Review of Current Literature

Streptococcal Toxic Shock Syndrome with Multiple Cerebral Infarctions Caused by Streptococcus dysgalactiae subsp. equisimilis: An Autopsy Case Report

We herein report an autopsy case of streptococcal toxic shock syndrome (STSS) with disseminated intravascular coagulation and multiple cerebral infarctions induced by Streptococcus dysgalactiae subsp. equisimilis in an 84-year-old male. Pathological examination revealed sepsis with hemophagocytosis in the reticular system and intravascular bacteria in multiple organs, originating from bacterial necrotizing fasciitis of the lower extremities. The brain MRI findings showed a diffusion weighted imaging-fluid-attenuated inversion-recovery mismatch, whereas the pathology was almost normal, thus supporting a hyperacute phase of cerebral infarction. The findings in this case help to elucidate the pathogenesis of STSS and develop appropriate treatment strategies.

3D imaging and pathological analysis of microglia in LPS-treated mice with light-sheet fluorescence microscopy

Although two-dimensional (2D) histology and immunohistochemistry techniques have long been established and successfully applied to obtain structural information from tissues, recent advances in tissue clearing and expansion approaches combined with light sheet microscopy have led to the realization of three-dimensional (3D) nondestructive pathology, which may revolutionize our knowledge of the morphology of an organ or the whole body in its true state. Employing these 3D technologies, we obtained imaging data of microglia in whole hippocampus of mice. We established a simple procedure to analyze the 3D structures of microglia using the commercial software Amira. Major 3D structural parameters, including the volume of the whole cell, volume of the cell body, Feret's maximum/minimum diameter, number of total branches, fractal dimension, convex hull, and number of intersections,were measured. We found that lipopolysaccharide administration markedly changed multiple 3D morphological parameters of microglia. 3D analysis of microglial structures provides a more comprehensive evaluation than 2D analysis, which can be applied in future neuroscience research.

The Role of Ultrasonographic Assessment of Optic Nerve Sheath Diameter in Prediction of Sepsis-Associated Encephalopathy: Prospective Observational Study

BACKGROUND

Ultrasonographic optic nerve sheath diameter (ONSD) is a satisfactory noninvasive intracranial pressure (ICP) monitoring test. Our aim was to evaluate ONSD as an objective screening tool to predict and diagnose ICP changes early in sepsis-associated encephalopathy (SAE).

METHODS

Our prospective observational study was conducted on patients with sepsis, and after intensive care unit (ICU) admission, the time to diagnose SAE was recorded, and patients were divided into a non-SAE group including conscious patients with sepsis and a SAE group including patients with sepsis with acute onset of disturbed conscious level. ONSD was measured within 24 h of ICU admission for all patients and then every other day for up to 10 consecutive days until ICU discharge or death. The primary outcome was to compare ONSD measurements of both groups to find if there was a correlation between ONSD and SAE occurrence.

RESULTS

Eighty-nine patients with sepsis were divided into a non-SAE group (n = 45) and an SAE group (n = 44). ONSD showed a statistically significant difference at day 0 and a highly significant difference at days 2, 4, 6, 8, and 10. Day 2 ONSD had the best accuracy for predicting SAE, with a cutoff > 5.2 mm (sensitivity of 93.2%, specificity of 100%), a statistically positive correlation with the Sequential Organ Failure Assessment score (r = 0.485, P < 0.001) and ICU length of stay (r = 0.238, P < 0.001), and a statistically significant wider in patients who died compared to those who survived (P < 0.001).

CONCLUSIONS

ONSD could be an objective screening method for early diagnosis of SAE, with a cutoff > 5.2 mm. Trial registration NCT05849831 ( https://clinicaltrials.gov/study/NCT05849831 ).

A Critical Reappraisal of Haloperidol for Delirium Management in the Intensive Care Unit: Perspective from Psychiatry

Delirium is a complex neuropsychiatric syndrome with multifactorial pathophysiology, encompassing a wide range of neuropsychiatric symptoms, and its management remains a significant challenge in critical care. Although often managed with antipsychotics, like haloperidol, current research has predominantly focused on dopamine dysregulation as the primary driver of delirium, overlooking its broader neuroanatomical and neurochemical underpinnings. This has led to a majority of research focusing on haloperidol as a treatment for intensive care unit (ICU) delirium. Our review critically evaluates the role of haloperidol in ICU delirium management, particularly in light of recent large-scale randomized controlled trials (RCTs) that have primarily focused on delirium-free days and mortality as the primary endpoints. These studies highlight an limited understanding of the true nature of delirium treatment, which requires a broader, neuropsychiatric approach. We argue that future research should shift focus to neuropsychiatric symptoms such as agitation and psychosis and explore the clinical and functional benefits of reducing these distressing symptoms. Additionally, the stratification of delirium by subtypes and etiology, the enhancement of detection tools, and the adoption of multi-intervention and multi-disciplinary care approaches should be prioritized. Despite the methodological flaws in these studies, the findings support the safety of haloperidol in the ICU setting, with minimal risk of adverse events, particularly cardiac and neuropsychiatric. Moving forward, delirium research must integrate modern neuroscientific understanding and adopt more multi-disciplinary input and nuanced, patient-centered approaches to truly advance clinical care and outcomes.

NOD-like receptor protein 3 inhibition by MCC950 improves the cognitive function of rats with sepsis-associated encephalopathy

This study aimed to investigate the effects of MCC950 in a rat model of sepsis-associated encephalopathy (SAE). Adult male rats were randomly assigned to 12 groups according to the surgery or treatment received and evaluation times. The SAE model was established using the cecal ligation and puncture (CLP) method. Intraperitoneal injections of normal saline (10 mL/kg) or MCC950 (10 mg/kg) were administered 30 min pre-surgery and daily post-surgery. Changes in survival rates, weight loss, and heart rate were assessed at four time points, and neurobehavioral changes were evaluated using the composite neural reflex function scores, light/dark box test, and open-field test (OFT). Compared with the SAE group, the SAE + MCC950 group had significantly higher survival rates (P < 0.05), lower postoperative weight loss rates (P < 0.05), and higher neurological function scores (P < 0.05); the SAE + MCC950 group also traveled further and crossed the central area more frequently in the OFT (P < 0.05), spent more time in the light compartment at different time points (P < 0.05), and exhibited a lower heart rate at different time points (P < 0.05). MCC950 treatment significantly improved cognitive function and related indices in the SAE rats.

Norepinephrine titration in patients with sepsis-induced encephalopathy: cerebral pulsatility index compared to mean arterial pressure guided protocol: randomized controlled trial

BACKGROUND

Although surviving sepsis campaign (SSC) guidelines are the standard for sepsis and septic shock management, outcomes are still unfavourable. Given that perfusion pressure in sepsis is heterogeneous among patients and within the same patient; we evaluated the impact of individualized hemodynamic management via the transcranial Doppler (TCD) pulsatility index (PI) on mortality and outcomes among sepsis-induced encephalopathy (SIE) patients.

METHODS

In this prospective, single-center randomized controlled study, 112 patients with SIE were randomly assigned. Mean arterial pressure (MAP) and norepinephrine (NE) titration were guided via the TCD pulsatility index to achieve a pulsatility index < 1.3 in Group I, whereas the SSC guidelines were used in Group II to achieve a MAP ≥ 65 mmHg. The primary outcome was intensive care unit (ICU) mortality and the secondary outcomes were; MAP that was measured invasively and values were recorded; daily in the morning, at the end of NE infusion and the end of ICU stay, duration of ICU stay, cerebral perfusion pressure (CPP), sequential organ failure assessment (SOFA) score, norepinephrine titration and Glasgow coma scale (GCS) score at discharge.

RESULTS

ICU mortality percentage wasn`t significantly different between the two groups (p value 0.174). There was a significant increase in the MAP at the end of norepinephrine infusion (mean value of 69.54 ± 10.42 and p value 0.002) and in the GCS score at ICU discharge (Median value of 15 and p value 0.014) in the TCD group, and episodes of cerebral hypoperfusion with CPP < 60 mmHg, were significantly lower in the TCD group (median value of 2 and p value 0.018). Heart rate values, number of episodes of tachycardia or bradycardia, Total norepinephrine dosing, duration of norepinephrine infusion, SOFA score, serum lactate levels, and ICU stay duration weren`t significantly different between the two groups.

CONCLUSIONS

Individualizing hemodynamic management via the TCD pulsatility index in SIE patients was not associated with significant mortality reduction. However, it reduces episodes of cerebral hypoperfusion and improves GCS outcome but doesn't significantly affect heart rate values, SOFA score, serum lactate level, length of ICU stay, total NE dosing, and duration of NE infusion.

TRIAL REGISTRATION

The clinical trial was registered on clinucaltrials.gov under the identifier NCT05842616 https://clinicaltrials.gov/study/NCT05842616?cond=NCT05842616&rank=1 on 6-May-2023 before the enrolment of the first patient.

Brain Ultrasonography in Critically Ill Septic Patients: A Scoping Review

Sepsis-associated encephalopathy (SAE) is linked to high mortality and impaired neurologic outcome. Brain ultrasonography (US) is a non-invasive tool for cerebral monitoring. A scoping review of the literature in three databases was performed to answer if brain perfusion is altered in sepsis, to determine the role of brain US in guiding resuscitation and its ability to predict the outcome. Randomized controlled trials, clinical trials, observational studies, and systematic reviews on adults with sepsis or septic shock in the ICU were included. A total of 625 articles were screened, and 34 included. There were 85% observational studies and 15% systematic reviews with or without meta-analysis. The majority of studies had a small sample size and used different metrics. The studies focused on cerebral blood flow (CBF) alterations reporting variable results (CBF increased, normal, or decreased). The findings showed a variable rate of cerebral autoregulation (CAR) impairment, with higher incidence in the early stages of sepsis and associations with poor neurological outcomes. However, the impact of CAR and CBF alterations on neurological outcomes and mortality was not clear. Very few studies were found on resuscitation. In conclusion, brain US can identify cerebral perfusions alterations and its usage in sepsis is promising. However, the current body of evidence for its usage is poor and lacks standardization.

The ROS/TXNIP/NLRP3 pathway mediates LPS-induced microglial inflammatory response

BACKGROUND

Sepsis-associated encephalopathy (SAE) is a diffuse brain dysfunction activated by microglia. The potential pathological changes of SAE are complex, and the cellular pathophysiological characteristics remains unclear. This study aims to explore the ROS/TXNIP/NLRP3 pathway mediated lipopolysaccharide (LPS)-induced inflammatory response in microglia.

METHODS

BV-2 cells were pre-incubated with 10 μM N-acetyl-L-cysteine (NAC) for 2 h, which were then reacted with 1 μg/mL LPS for 24 h. Western blot assay examined the protein levels of IBA1, CD68, TXNIP, NLRP3, ASC, and Cleaved Caspase-1 in BV-2 cells. The contents of inflammatory factor were detected by ELISA assay. The co-immunoprecipitation assay examined the interaction between TXNIP and NLRP3.

RESULTS

LPS was confirmed to promote the positive expressions of IBA1 and CD68 in BV-2 cells. The further experiments indicated that LPS enhanced ROS production and NLRP3 inflammasome activation in BV-2 cells. Moreover, we also found that NAC partially reversed the facilitation of LPS on the levels of ROS, IL-1β, IL-18, TXNIP, NLRP3, ASC, and Cleaved Caspase-1 in BV-2 cells. NAC treatment also notably alleviated the interaction between TXNIP and NLRP3 in BV-2 cells.

CONCLUSION

ROS inhibition mediated NLRP3 signaling inactivation by decreasing TXNIP expression.

Gibberellic acid targeting ZBTB16 reduces NF-κB dependent inflammatory stress in sepsis-induced neuroinflammation

OBJECTIVE

Sepsis is frequently complicated by neuroinflammation. Gibberellic acid (GA3) is recognized for its anti-inflammatory properties. In this study, our objective was to investigate whether GA3 could alleviate Nuclear factor-kappa B (NF-κB) -dependent inflammatory stress in sepsis-induced neuroinflammation.

METHODS

C57BL/6 J mice were administered 10 mg/kg lipopolysaccharide (LPS) to induce sepsis. BV2 cells were pre-incubated with GA3 and subjected lipopolysaccharide stimulation to replicate the inflammatory microglia during sepsis. Subsequently, we assessed the release of IL-6, TNF-α, and IL-1β, along with the expression of Zbtb16, NF-κB, and IκB. To investigate whether any observed anti-inflammatory effects of GA3 were mediated through a Zbtb16-dependent mechanism, Zbtb16 was silenced using siRNA.

RESULTS

GA3 improved the survival of sepsis mice and alleviated post-sepsis cognitive impairment. Additionally, GA3 attenuated microglial M1 activation (pro-inflammatory phenotype), inflammation, and neuronal damage in the brain. Moreover, GA3 inhibited the release of TNF-α, IL-6, and IL-1β in microglia stimulated with LPS. The NF-κB signaling pathway emerged as one of the key molecular pathways associated with the impact of GA3 on LPS-stimulated microglia. Lastly, GA3 upregulated Zbtb16 expression in microglia that had been downregulated by LPS. The inhibitory effects of GA3 on microglial M1 activation were partially reversed through siRNA knockdown of Zbtb16.

CONCLUSIONS

Pre-incubation of microglia with GA3 led to the upregulation of the NF-κB regulator, Zbtb16. This process counteracted LPS-induced microglial M1 activation, resulting in an anti-inflammatory effect upon subsequent LPS stimulation.

A narrative review of neuromonitoring modalities in critically ill children

Acute neurologic injury is common in critically ill children. Some conditions - such as traumatic brain injury, meningitis, and hypoxic-ischemic injury following cardiac arrest - require careful consideration of cerebral physiology. Specialized neuromonitoring techniques provide insight regarding patient-specific and disease-specific insight that can improve diagnostic accuracy, aid in targeting therapeutic interventions, and provide prognostic information. In this review, we will discuss recent innovations in invasive (e.g., intracranial pressure monitoring and related computed indices) and noninvasive (e.g., transcranial doppler, near-infrared spectroscopy) neuromonitoring techniques used in traumatic brain injury, central nervous system infections, and after cardiac arrest. We will discuss the pertinent physiological mechanisms interrogated by each technique and discuss available evidence for potential clinical application. We will also discuss the use of innovative neuromonitoring techniques to detect and manage neurologic complications in critically ill children with systemic illness, focusing on sepsis and cardiorespiratory failure requiring extracorporeal membrane oxygenation.

The Indian Society of Critical Care Medicine Position Statement on the Management of Sepsis in Resource-limited Settings

Sepsis poses a significant global health challenge in low- and middle-income countries (LMICs). Several aspects of sepsis management recommended in international guidelines are often difficult or impossible to implement in resource-limited settings (RLS) due to issues related to cost, infrastructure, or lack of trained healthcare workers. The Indian Society of Critical Care Medicine (ISCCM) drafted a position statement for the management of sepsis in RLS focusing on India, facilitated by a task force of 18 intensivists using a Delphi process, to achieve consensus on various aspects of sepsis management which are challenging to implement in RLS. The process involved a comprehensive literature review, controlled feedback, and four iterative surveys conducted between 21 August 2023 and 21 September 2023. The domains addressed in the Delphi process included the need for a position statement, challenges in sepsis management, considerations for diagnosis, patient management while awaiting an intensive care unit (ICU) bed, and treatment of sepsis and septic shock in RLS. Consensus was achieved when 70% or more of the task force members voted either for or against statements using a Likert scale or a multiple-choice question (MCQ). The Delphi process with 100% participation of Task Force members in all rounds, generated consensus in 32 statements (91%) from which 20 clinical practice statements were drafted for the management of sepsis in RLS. The clinical practice statements will complement the existing international guidelines for the management of sepsis and provide valuable insights into tailoring sepsis interventions in the context of RLS, contributing to the global discourse on sepsis management. Future international guidelines should address the management of sepsis in RLS.

How to cite this article

Juneja D, Nasa P, Chanchalani G, Cherian A, Jagiasi BG, Javeri Y, et al. The Indian Society of Critical Care Medicine Position Statement on the Management of Sepsis in Resource-limited Settings. Indian J Crit Care Med 2024;28(S2):S4-S19.

Is NEWS of value for patients with acute stroke?

BACKGROUND

Patients with acute stroke are at risk of respiratory or circulatory compromise resulting in vital instability, which can be captured through the widely used aggregated National Early Warning Score (NEWS). We aimed to assess the relation between vital instability (defined as NEWS of five or higher) and death or dependency at 90 days after stroke.

METHODS

In this observational cohort study we studied 763 patients with ischaemic stroke (n = 400), intracerebral haemorrhage (ICH) (n = 146) or subarachnoid haemorrhage (SAH) (n = 217), hospitalized to a Dutch tertiary referral hospital from 1 January 2017 to 31 December 2018. We calculated NEWS for each 8 h time span during the first 72 h after hospitalization. We also decomposed NEWS into its three components respiration, circulation and consciousness. The primary outcome was death or dependency (modified Rankin Scale score ⩾3) at 90 days after stroke. The association of vital instability with functional dependency was examined using Poisson regression.

RESULTS

Two hundred and twenty-seven (58%) patients with ischaemic stroke, 101 (69%) with ICH and 142 (65%) with SAH had at least one episode of vital instability. In patients with ischaemic stroke or SAH, vital instability was associated after adjustment for confounders with death or dependency (adjusted relative risk 1.55 ((95% CI) 1.25-1.93 and 2.13 (1.35-3.36), respectively)). This was mainly driven by impaired consciousness, which was associated with death or dependency in all types of stroke. Respiratory insufficiency and circulatory instability were associated with death or dependency only in SAH.

CONCLUSION

Vital instability in the first 72 h of hospitalization for ischaemic stroke or SAH is associated with death or dependency at 90 days. Impaired consciousness was the main driver of this relationship. NEWS may not be appropriate for patients with acute stroke, mainly due to the dichotomous manner in which the level of consciousness is classified, and modification of NEWS should be considered for these patients.

Essential New Complexity-Based Themes for Patient-Centered Diagnosis and Treatment of Dementia and Predementia in Older People: Multimorbidity and Multilevel Phenomenology

Dementia is a highly prevalent condition with devastating clinical and socioeconomic sequela. It is expected to triple in prevalence by 2050. No treatment is currently known to be effective. Symptomatic late-onset dementia and predementia (SLODP) affects 95% of patients with the syndrome. In contrast to trials of pharmacological prevention, no treatment is suggested to remediate or cure these symptomatic patients. SLODP but not young onset dementia is intensely associated with multimorbidity (MUM), including brain-perturbating conditions (BPCs). Recent studies showed that MUM/BPCs have a major role in the pathogenesis of SLODP. Fortunately, most MUM/BPCs are medically treatable, and thus, their treatment may modify and improve SLODP, relieving suffering and reducing its clinical and socioeconomic threats. Regrettably, the complex system features of SLODP impede the diagnosis and treatment of the potentially remediable conditions (PRCs) associated with them, mainly due to failure of pattern recognition and a flawed diagnostic workup. We suggest incorporating two SLODP-specific conceptual themes into the diagnostic workup: MUM/BPC and multilevel phenomenological themes. By doing so, we were able to improve the diagnostic accuracy of SLODP components and optimize detecting and favorably treating PRCs. These revolutionary concepts and their implications for remediability and other parameters are discussed in the paper.

Factors contributing to sepsis-associated encephalopathy: a comprehensive systematic review and meta-analysis

Background

This study aims to systematically assess the risk factors, the overall strength of association, and evidence quality related to sepsis-associated encephalopathy.

Methods

A systematic search was conducted in the Cochrane Library, PubMed, Web of Science, and Embase for cohort or case-control studies published up to August 2023 on risk factors associated with sepsis-related encephalopathy. The selected studies were screened, data were extracted, and the quality was evaluated using the Newcastle-Ottawa Scale. Meta-analysis was performed using RevMan 5.3 software. The certainty of the evidence was assessed using the GRADE criteria.

Results

A total of 13 studies involving 1,906 participants were included in the analysis. Among these studies, 12 were of high quality, and one was of moderate quality. Our meta-analysis identified six risk factors significantly associated with Serious Adverse Events (SAE). These included APACHE II, SOFA, age, tau protein, and IL-6, which were found to be risk factors with significant effects (standard mean difference SMD: 1.24-2.30), and albumin, which was a risk factor with moderate effects (SMD: -0.55). However, the certainty of evidence for the risk factors identified in this meta-analysis ranged from low to medium.

Conclusion

This systematic review and meta-analysis identified several risk factors with moderate to significant effects. APACHE II, SOFA, age, tau protein, IL-6, and albumin were associated with sepsis-related encephalopathy and were supported by medium- to high-quality evidence. These findings provide healthcare professionals with an evidence-based foundation for managing and treating hospitalized adult patients with sepsis-related encephalopathy.

Clinical image of sepsis-associated encephalopathy midst E. coli urosepsis: Emergency department database study

Background

Sepsis is a life-threatening organ dysfunction caused by a dysregulated host response to infection, which, if untreated, leads to multi-organ failure. One of the severe possible complications is sepsis associated encephalopathy (SAE), a neurological dysfunction occurring secondary to a severe inflammatory response. It manifests as acute cognitive dysfunction and sudden-onset dysfunctions in mental state. Uropathogenic Escherichia coli is the most common pathogen causing bacteremia, responsible for 80% of uncomplicated outpatient urinary tract infections and 40% of nosocomial infections. The study aimed to assess the difference in the severity and the course of urosepsis caused by E. coli in patients with and without septic encephalopathy.

Materials and methods

This study presents a retrospective analysis of the population of urosepsis patients admitted to the Emergency Department between September 2019 and June 2022. Inflammatory parameters, urinalysis and blood cultures were performed, along with a clinical evaluation of sepsis severity and encephalopathy. The patients were then stratified into SAE and non-SAE groups based on neurological manifestations and compared according to the collected data.

Results

A total of 199 septic patients were included in the study. E. coli-induced urosepsis was diagnosed in 84 patients. In this group, SAE was diagnosed in 31 (36.9%) patients (33.3% in males, 40.5% females). Patients with SAE were found to be hypotensive (p < 0,005), with a higher respiratory rate (p < 0,017) resulting in a higher mortality rate (p = 0.002) compared to non-SAE septic patients. The APACHE II score was an independent risk factor associated with a higher mortality rate. Biochemical parameters between the groups did not show any statistical importance related to the severity of urosepsis.

Conclusions

The severity of urosepsis and risk of SAE development increase according to the clinical condition and underlying comorbidities. Urosepsis patients with SAE are at a higher risk of death. Patients should undergo more careful screening for the presence of SAE on admission, and more intense monitoring and treatment should be provided for patients with SAE. This study indicates the need to develop projects aiming to further investigate neuroprotective interventions in sepsis.

Lipid peroxidation-induced ferroptosis as a therapeutic target for mitigating neuronal injury and inflammation in sepsis-associated encephalopathy: insights into the hippocampal PEBP-1/15-LOX/GPX4 pathway

BACKGROUND

Sepsis-associated encephalopathy (SAE) refers to the widespread impairment of brain function caused by noncentral nervous system infection mediated by sepsis. Lipid peroxidation-induced ferroptosis contributes to the occurrence and course of SAE. This study aimed to investigate the relationship between neuronal injury and lipid peroxidation-induced ferroptosis in SAE.

METHODS

Baseline data were collected from pediatric patients upon admission, and the expression levels of various markers related to lipid peroxidation and ferroptosis were monitored in the serum and peripheral blood mononuclear cells (PBMCs) of patients with SAE as well as SAE model mice. The hippocampal phosphatidylethanolamine-binding protein (PEBP)-1/15-lysine oxidase (LOX)/ glutathione peroxidase 4 (GPX4) pathway was assessed for its role on the inhibitory effect of ferroptosis in SAE treatment.

RESULTS

The results showed elevated levels of S100 calcium-binding protein beta (S-100β), glial fibrillary acidic protein, and malondialdehyde in the serum of SAE patients, while superoxide dismutase levels were reduced. Furthermore, analysis of PBMCs revealed increased transcription levels of PEBP1, LOX, and long-chain fatty acyl-CoA synthetase family member 4 (ACSL4) in SAE patients, while the transcription levels of GPX4 and cystine/glutamate transporter xCT (SLC7A11) were decreased. In comparison to the control group, the SAE mice exhibited increased expression of S-100β and neuron-specific enolase (NSE) in the hippocampus, whereas the expression of S-100β and NSE were reduced in deferoxamine (DFO) mice. Additionally, iron accumulation was observed in the hippocampus of SAE mice, while the iron ion levels were reduced in the DFO mice. Inhibition of ferroptosis alleviated the mitochondrial damage (as assessed by transmission electron microscopy, hippocampal mitochondrial ATP detection, and the JC-1 polymer-to-monomer ratio in the hippocampus) and the oxidative stress response induced by SAE as well as attenuated neuroinflammatory reactions. Further investigations revealed that the mechanism underlying the inhibitory effect of ferroptosis in SAE treatment is associated with the hippocampal PEBP-1/15-LOX/GPX4 pathway.

CONCLUSION

These results offer potential therapeutic targets for the management of neuronal injury in SAE and valuable insights into the potential mechanisms of ferroptosis in neurological disorders.

Estimated Cerebral Perfusion Pressure and Intracranial Pressure in Septic Patients

BACKGROUND

Sepsis-associated brain dysfunction (SABD) is frequent and is associated with poor outcome. Changes in brain hemodynamics remain poorly described in this setting. The aim of this study was to investigate the alterations of cerebral perfusion pressure and intracranial pressure in a cohort of septic patients.

METHODS

We conducted a retrospective analysis of prospectively collected data in septic adults admitted to our intensive care unit (ICU). We included patients in whom transcranial Doppler recording performed within 48 h from diagnosis of sepsis was available. Exclusion criteria were intracranial disease, known vascular stenosis, cardiac arrhythmias, pacemaker, mechanical cardiac support, severe hypotension, and severe hypocapnia or hypercapnia. SABD was clinically diagnosed by the attending physician, anytime during the ICU stay. Estimated cerebral perfusion pressure (eCPP) and estimated intracranial pressure (eICP) were calculated from the blood flow velocity of the middle cerebral artery and invasive arterial pressure using a previously validated formula. Normal eCPP was defined as eCPP ≥ 60 mm Hg, low eCPP was defined as eCPP < 60 mm Hg; normal eICP was defined as eICP ≤ 20 mm Hg, and high eICP was defined as eICP > 20 mm Hg.

RESULTS

A total of 132 patients were included in the final analysis (71% male, median [interquartile range (IQR)] age was 64 [52-71] years, median [IQR] Acute Physiology and Chronic Health Evaluation II score on admission was 21 [15-28]). Sixty-nine (49%) patients developed SABD during the ICU stay, and 38 (29%) were dead at hospital discharge. Transcranial Doppler recording lasted 9 (IQR 7-12) min. Median (IQR) eCPP was 63 (58-71) mm Hg in the cohort; 44 of 132 (33%) patients had low eCPP. Median (IQR) eICP was 8 (4-13) mm Hg; five (4%) patients had high eICP. SABD occurrence and in-hospital mortality did not differ between patients with normal eCPP and patients with low eCPP or between patients with normal eICP and patients with high eICP. Eighty-six (65%) patients had normal eCPP and normal eICP, 41 (31%) patients had low eCPP and normal eICP, three (2%) patients had low eCPP and high eICP, and two (2%) patients had normal eCPP and high eICP; however, SABD occurrence and in-hospital mortality were not significantly different among these subgroups.

CONCLUSIONS

Brain hemodynamics, in particular CPP, were altered in one third of critically ill septic patients at a steady state of monitoring performed early during the course of sepsis. However, these alterations were equally common in patients who developed or did not develop SABD during the ICU stay and in patients with favorable or unfavorable outcome.

Maresins as novel anti-inflammatory actors and putative therapeutic targets in sepsis

Sepsis, a complex clinical syndrome characterized by an exaggerated host response to infection, often necessitates hospitalization and intensive care unit admission. Delayed or inaccurate diagnosis of sepsis, coupled with suboptimal treatment strategies, can result in unfavorable outcomes, including mortality. Maresins, a newly discovered family of lipid mediators synthesized from docosahexaenoic acid by macrophages, have emerged as key players in promoting inflammation resolution and the termination of inflammatory processes. Extensive evidence has unequivocally demonstrated the beneficial effects of maresins in modulating the inflammatory response associated with sepsis; however, their bioactivity and functions exhibit remarkable diversity and complexity. This article presents a comprehensive review of recent research on the role of maresins in sepsis, aiming to enhance our understanding of their effectiveness and elucidate the specific mechanisms underlying their actions in sepsis treatment. Furthermore, emerging insights into the management of patients with sepsis are also highlighted.

Improved prediction of sepsis-associated encephalopathy in intensive care unit sepsis patients with an innovative nomogram tool

Background

Sepsis-associated encephalopathy (SAE) occurs as a result of systemic inflammation caused by sepsis. It has been observed that the majority of sepsis patients experience SAE while being treated in the intensive care unit (ICU), and a significant number of survivors continue suffering from cognitive impairment even after recovering from the illness. The objective of this study was to create a predictive nomogram that could be used to identify SAE risk factors in patients with ICU sepsis.

Methods

We conducted a retrospective cohort study using the Medical Information Mart for Intensive Care IV (MIMIC-IV) database. We defined SAE as a Glasgow Coma Scale (GCS) score of 15 or less, or delirium. The patients were randomly divided into training and validation cohorts. We used least absolute shrinkage and selection operator (LASSO) regression modeling to optimize feature selection. Independent risk factors were determined through a multivariable logistic regression analysis, and a prediction model was built. The performance of the nomogram was evaluated using various metrics including the area under the receiver operating characteristic curve (AUC), calibration plots, Hosmer-Lemeshow test, decision curve analysis (DCA), net reclassification improvement (NRI), and integrated discrimination improvement (IDI).

Results

Among the 4,476 sepsis patients screened, 2,781 (62.1%) developed SAE. In-hospital mortality was higher in the SAE group compared to the non-SAE group (9.5% vs. 3.7%, p < 0.001). Several variables were analyzed, including the patient's age, gender, BMI on admission, mean arterial pressure, body temperature, platelet count, sodium level, and use of midazolam. These variables were used to create and validate a nomogram. The nomogram's performance, assessed by AUC, NRI, IDI, and DCA, was found to be superior to the conventional SOFA score combined with delirium. Calibration plots and the Hosmer-Lemeshow test confirmed the accuracy of the nomogram. The enhanced NRI and IDI values demonstrated that our scoring system outperformed traditional diagnostic approaches. Additionally, the DCA curve indicated the practicality of the nomogram in clinical settings.

Conclusion

This study successfully identified autonomous risk factors associated with the emergence of SAE in sepsis patients and utilized them to formulate a predictive model. The outcomes of this investigation have the potential to serve as a valuable clinical resource for the timely detection of SAE in patients.

Glucocorticoids with or without fludrocortisone in septic shock: a narrative review from a biochemical and molecular perspective

Two randomised controlled trials have reported a reduction in mortality when adjunctive hydrocortisone is administered in combination with fludrocortisone compared with placebo in septic shock. A third trial did not support this finding when hydrocortisone administered in combination with fludrocortisone was compared with hydrocortisone alone. The underlying mechanisms for this mortality benefit remain poorly understood. We review the clinical implications and potential mechanisms derived from laboratory and clinical data underlying the beneficial role of adjunctive fludrocortisone with hydrocortisone supplementation in septic shock. Factors including distinct biological effects of glucocorticoids and mineralocorticoids, tissue-specific and mineralocorticoid receptor-independent effects of mineralocorticoids, and differences in downstream signalling pathways between mineralocorticoid and glucocorticoid binding at the mineralocorticoid receptor could contribute to this interaction. Furthermore, pharmacokinetic and pharmacodynamic disparities exist between aldosterone and its synthetic counterpart fludrocortisone, potentially influencing their effects. Pending publication of well-designed, randomised controlled trials, a molecular perspective offers valuable insights and guidance to help inform clinical strategies.

Sepsis-associated encephalopathy: From pathophysiology to clinical management

Sepsis-associated encephalopathy, which presents as delirium and coma, is a significant complication of sepsis characterized by acute brain dysfunction. The presence of inflammatory pathological changes in the brain of sepsis patients and animal models has been recognized since the 1920 s, initially attributed to the entry of microbial toxins into the brain. In the early 2000 s, attention shifted towards the impact of oxidative stress, the cholinergic system, and cytokines on brain function following sepsis onset. More recently, sepsis-associated encephalopathy has been defined as a diffuse brain dysfunction not directly caused by pathogenic infection of the brain. Currently, there is no evidence-based standard for diagnosing sepsis-associated encephalopathy, and clinical management is primarily focused on symptomatic and supportive measures. This review aims to explore the pathophysiology of sepsis-associated encephalopathy and establish the connection between pathophysiological mechanisms and clinical characteristics. We hope that this work will spark the interest of researchers from various fields and contribute to the advancement of sepsis-associated encephalopathy research.

Extracellular Vesicles as Possible Plasma Markers and Mediators in Patients with Sepsis-Associated Delirium-A Pilot Study

Patients with sepsis-associated delirium (SAD) show severe neurological impairment, often require an intensive care unit (ICU) stay and have a high risk of mortality. Hence, useful biomarkers for early detection of SAD are urgently needed. Extracellular vesicles (EVs) and their cargo are known to maintain normal physiology but also have been linked to numerous disease states. Here, we sought to identify differentially expressed proteins in plasma EVs from SAD patients as potential biomarkers for SAD. Plasma EVs from 11 SAD patients and 11 age-matched septic patients without delirium (non-SAD) were isolated by differential centrifugation, characterized by nanoparticle tracking analysis, transmission electron microscopy and Western blot analysis. Differential EV protein expression was determined by mass spectrometry and the resulting proteomes were characterized by Gene Ontology term and between-group statistics. As preliminary results because of the small group size, five distinct proteins showed significantly different expression pattern between SAD and non-SAD patients (p ≤ 0.05). In SAD patients, upregulated proteins included paraoxonase-1 (PON1), thrombospondin 1 (THBS1), and full fibrinogen gamma chain (FGG), whereas downregulated proteins comprised immunoglobulin (IgHV3) and complement subcomponent (C1QC). Thus, plasma EVs of SAD patients show significant changes in the expression of distinct proteins involved in immune system regulation and blood coagulation as well as in lipid metabolism in this pilot study. They might be a potential indicator for to the pathogenesis of SAD and thus warrant further examination as potential biomarkers, but further research is needed to expand on these findings in longitudinal study designs with larger samples and comprehensive polymodal data collection.

An Fgr kinase inhibitor attenuates sepsis-associated encephalopathy by ameliorating mitochondrial dysfunction, oxidative stress, and neuroinflammation via the SIRT1/PGC-1α signaling pathway

BACKGROUND

Sepsis-associated encephalopathy (SAE) is characterized by diffuse brain dysfunction, long-term cognitive impairment, and increased morbidity and mortality. The current treatment for SAE is mainly symptomatic; the lack of specific treatment options and a poor understanding of the underlying mechanism of disease are responsible for poor patient outcomes. Fgr is a member of the Src family of tyrosine kinases and is involved in the innate immune response, hematologic cancer, diet-induced obesity, and hemorrhage-induced thalamic pain. This study investigated the protection provided by an Fgr kinase inhibitor in SAE and the underlying mechanism(s) of action.

METHODS

A cecal ligation and puncture (CLP)-induced mouse sepsis model was established. Mice were treated with or without an Fgr inhibitor and a PGC-1α inhibitor/activator. An open field test, a novel object recognition test, and an elevated plus maze were used to assess neurobehavioral changes in the mice. Western blotting and immunofluorescence were used to measure protein expression, and mRNA levels were measured using quantitative PCR (qPCR). An enzyme-linked immunosorbent assay was performed to quantify inflammatory cytokines. Mitochondrial membrane potential and morphology were measured by JC-1, electron microscopy, and the MitoTracker Deep Red probe. Oxidative stress and mitochondrial dysfunction were analyzed. In addition, the regulatory effect of Fgr on sirtuin 1 (SIRT1) was assessed.

RESULTS

CLP-induced sepsis increased the expression of Fgr in the hippocampal neurons. Pharmacological inhibition of Fgr attenuated CLP-induced neuroinflammation, the survival rate, cognitive and emotional dysfunction, oxidative stress, and mitochondrial dysfunction. Moreover, Fgr interacted with SIRT1 and reduced its activity and expression. In addition, activation of SIRT1/PGC-1α promoted the protective effects of the Fgr inhibitor on CLP-induced brain dysfunction, while inactivation of SIRT1/PGC-1α counteracted the benefits of the Fgr inhibitor.

CONCLUSIONS

To our knowledge, this is the first report of Fgr kinase inhibition markedly ameliorating SAE through activation of the SIRT1/PGC-1α pathway, and this may be a promising therapeutic target for SAE.

The association between the presence and burden of periodic discharges and outcome in septic patients: an observational prospective study

BACKGROUND

Sepsis-associated encephalopathy (SAE) is frequent in septic patients. Electroencephalography (EEG) is very sensitive to detect early epileptic abnormalities, such as seizures and periodic discharges (PDs), and to quantify their duration (the so-called burden). However, the prevalence of these EEG abnormalities in septic patients, as well as their effect on morbidity and mortality, are still unclear. The aims of this study were to assess whether the presence of electrographic abnormalities (i.e. the absence of reactivity, the presence and burden of seizures and PDs) was associated with functional outcome and mortality in septic patients and whether these abnormalities were associated with sepsis-associated encephalopathy (SAE).

METHODS

We prospectively included septic patients, without known chronic or acute intracranial disease or pre-existing acute encephalopathy, requiring ICU admission in a tertiary academic centre. Continuous EEG monitoring was started within 72 h after inclusion and performed for up to 7 days. A comprehensive assessment of consciousness and delirium was performed twice daily by a trained neuropsychologist. Primary endpoints were unfavourable functional outcome (UO, defined as a Glasgow Outcome Scale-Extended-GOSE-score < 5), and mortality collected at hospital discharge and secondary endpoint was the association of PDs with SAE. Mann-Whitney, Fisher's exact and χ2 tests were used to assess differences in variables between groups, as appropriate. Multivariable logistic regression analysis with in-hospital mortality, functional outcome, SAE or PDs as the dependent variables were performed.

RESULTS

We included 92 patients. No seizures were identified. Nearly 25% of patients had PDs. The presence of PDs and PDs burden was associated with UO in univariate (n = 15 [41%], p = 0.005 and p = 0.008, respectively) and, for PDs presence, also in multivariate analysis after correcting for disease severity (OR 3.82, IC 95% [1.27-11.49], p = 0.02). The PDs burden negatively correlated with GOSE (Spearman's coefficient ρ = - 0.2, p = 0.047). The presence of PDs was also independently associated with SAE (OR 8.98 [1.11-72.8], p = 0.04). Reactivity was observed in the majority of patients and was associated with outcomes (p = 0.044 for both functional outcome and mortality).

CONCLUSION

Our findings suggest that PDs and PDs burden are associated with SAE and might affect outcome in septic patients.

Liensinine, a alkaloid from lotus plumule, mitigates lipopolysaccharide-induced sepsis-associated encephalopathy through modulation of nuclear factor erythroid 2-related factor-mediated inflammatory biomarkers and mitochondria apoptosis

The present study aims to investigate the role of liensinine in life-threatened sepsis-associated encephalopathy (SAE) mice and the underlying mechanism. Here, seventy-two mice were divided into six groups, including the control group, SAE group, liensinine-treated group, and three doses of liensinine-treated SAE groups. Lipopolysaccharide triggered cerebrum necrosis and disrupted the integrity and permeability of blood-brain barrier (BBB). While liensinine restored cerebrum structure and improved BBB integrity with upregulated tight junction proteins, decreased evans blue leakage and fibrinogen expression with decreased matrix metalloproteinases 2/9 in serum, thereby reducing BBB permeability. Moreover, lipopolysaccharide triggered cerebrum oxidative stress and inflammation, whereas liensinine enhanced antioxidant enzymes activities and weakened malondialdehyde through nuclear factor erythroid 2-related factor. Meanwhile, liensinine inhibited inflammation by activating inducible nitric oxide synthase. Tunel staining combined with transmission electron microscope indicated that lipopolysaccharide induced cerebrum apoptosis, whereas liensinine blocked apoptosis through decreasing B-cell lymphoma-2 associated X (Bax) expression and cytochrome C (Cyto-c) release, increasing B-cell lymphoma-2 (Bcl-2) expression, blocking apoptosome assembly, inhibiting caspase-3 activation, thereby suppressing intrinsic mitochondria apoptosis. Recovering of inflammatory homeostasis and inhibition of mitochondria apoptosis by liensinine ultimately restored cognitive function in SAE mice. Altogether, liensinine attenuated lipopolysaccharide-induced SAE via modulation of Nrf2-mediated inflammatory biomarkers and mitochondria apoptosis.

Acetaldehyde dehydrogenase 2 activation attenuates sepsis-induced brain injury through NLRP3 inflammasome regulation

OBJECTIVE

Acetaldehyde dehydrogenase 2 (ALDH2) plays an important part in neuroprotection; however, its effect on sepsis-induced brain injury is nuclear. Our aim is to investigate the potential effect and mechanism of ALDH2 in this condition.

METHODS

We established an animal model using cecal ligation and perforation (CLP). Twenty-four rats were divided into sham group (n = 6), CLP group (n = 6), CLP + Alda-1 group (n = 6) and CLP + Cyanamide (CYA) group (n = 6). Vital signs were monitored, and arterial blood gas analysis, hippocampal histological staining and ALDH2 activity analysis were conducted. Western blot analysis and enzyme-linked immunosorbent assays were also carried out. Lipopolysaccharide (LPS)-treated HT22 cells were employed as an in vitro model of sepsis-induced brain injury, with and without pretreatment with Alda-1 or CYA, to further examine the potential mechanisms. Real-time quantitative polymerase chain reaction and western blot were used to determine the levels of pyrin domain-containing 3 (NLRP3) inflammasome.

RESULTS

We found hippocampal cell injury in the CLP group (p < 0.05), with decreased ALDH2 activity (p < 0.05) and suspected overexpression of NLRP3/caspase-1 axis (p < 0.05). In the group pretreated with Alda-1, there were increased ALDH2 activity (p < 0.05), decreased hippocampal cell damage (p < 0.05), and reduced protein levels of NLRP3, apoptosis-associated speck like protein containing a caspase recruitment domain (ASC), cleaved caspase-1 and Gasdermin D (GSDMD) (p < 0.05). The levels of interleukin 18 (IL-18) and interleukin 1β (IL-1β) were also reduced (p < 0.05). In the group pretreated with CYA, ALDH2 activity was further declined, the cell injury grade increased, and the elevated levels of pyroptosis-related proteins aggravated (p < 0.05). LPS treatment decreased the cell viability and ALDH2 activity of the HT22 cells (p < 0.05), along with increased mRNA levels of the NLRP3 inflammasome, as well as IL-1β and IL-18 (p < 0.05). Western blot further revealed elevated levels of NLRP3, ASC, cleaved caspase-1 and GSDMD (p < 0.05). In the LPS+Alda-1 group, there were increased cell viability (p < 0.05), elevated ALDH2 activity (p < 0.05), and reduced levels of NLRP3 inflammasome and pyroptosis-related proteins (p < 0.05). In the CYA+LPS group, cell viability and ALDH2 activity were further declined (p < 0.05), while levels of NLRP3 /caspase-1 axis were increased (p < 0.05).

CONCLUSIONS

The activation of ALDH2 can attenuate sepsis-induced brain injury, hypothetically through regulation of the NLRP3/caspase-1 signaling pathway. Therefore, ALDH2 could potentially be considered as a new therapeutic target for the treatment of sepsis-induced brain injury.

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.

Munc18-1 Contributes to Hippocampal Injury in Septic Rats Through Regulation of Syntanxin1A and Synaptophysin and Glutamate Levels

Sepsis-associated encephalopathy (SAE) is a diffuse brain dysfunction closely associated with mortality in the acute phase of sepsis. Abnormal neurotransmitters release, such as glutamate, plays a crucial role in the pathological mechanism of SAE. Munc18-1 is a key protein regulating neurotransmission. However, whether Munc18-1 plays a role in SAE by regulating glutamate transmission is still unclear. In this study, a septic rat model was established by the cecal ligation and perforation. We found an increase in the content of glutamate in the hippocampus of septic rat, the number of synaptic vesicles in the synaptic active area and the expression of the glutamate receptor NMDAR1. Meanwhile, it was found that the expressions of Munc18-1, Syntaxin1A and Synaptophysin increased, which are involved in neurotransmission. The expression levels of Syntaxin1A and Synaptophysin in hippocampus of septic rats decreased after interference using Munc18-1siRNA. We observed a decrease in the content of glutamate in the hippocampus of septic rats, the number of synaptic vesicles in the synaptic activity area and the expression of NMDAR1. Interestingly, it was also found that the down-regulation of Munc18-1 improved the vital signs of septic rats. This study shows that CLP induced the increased levels of glutamate in rat hippocampus, and Munc18-1 may participate in the process of hippocampal injury in septic rats by affecting the levels of glutamate via regulating Syntaxin1A and Synaptophysin. Munc18-1 may serve as a potential target for SAE therapy.

Prediction and risk assessment of sepsis-associated encephalopathy in ICU based on interpretable machine learning

Sepsis-associated encephalopathy (SAE) is a major complication of sepsis and is associated with high mortality and poor long-term prognosis. The purpose of this study is to develop interpretable machine learning models to predict the occurrence of SAE after ICU admission and implement the individual prediction and analysis. Patients with sepsis admitted to ICU were included. SAE was diagnosed as glasgow coma score (GCS) less than 15. Statistical analysis at baseline was performed between SAE and non-SAE. Six machine learning classifiers were employed to predict the occurrence of SAE, and the adjustment of model super parameters was performed by using Bayesian optimization method. Finally, the optimal algorithm was selected according to the prediction efficiency. In addition, professional physicians were invited to evaluate our model prediction results for further quantitative assessment of the model interpretability. The preliminary analysis of variance showed significant differences in the incidence of SAE among patients with pathogen infection. There were significant differences in physical indicators like respiratory rate, temperature, SpO₂ and mean arterial pressure (P < 0.001). In addition, the laboratory results were also significantly different. The optimal classification model (XGBoost) indicated that the best risk factors (cut-off points) were creatinine (1.1 mg/dl), mean respiratory rate (18), pH (7.38), age (72), chlorine (101 mmol/L), sodium (138.5 k/ul), SAPSII score (23), platelet count (160), and phosphorus (2.4 and 5.0 mg/dL). The ranked features derived from the best model (AUC is 0.8837) were mechanical ventilation, duration of mechanical ventilation, phosphorus, SOFA score, and vasopressin usage. The SAE risk prediction model based on XGBoost created here can make very accurate predictions using simple indicators and support the visual explanation. The interpretable model was effectively evaluated by professional physicians and can help them predict the occurrence of SAE more intuitively.

The biological alterations of synapse/synapse formation in sepsis-associated encephalopathy

Sepsis-associated encephalopathy (SAE) is a common complication caused by sepsis, and is responsible for increased mortality and poor outcomes in septic patients. Neurological dysfunction is one of the main manifestations of SAE patients. Patients may still have long-term cognitive impairment after hospital discharge, and the underlying mechanism is still unclear. Here, we first outline the pathophysiological changes of SAE, including neuroinflammation, glial activation, and blood-brain barrier (BBB) breakdown. Synapse dysfunction is one of the main contributors leading to neurological impairment. Therefore, we summarized SAE-induced synaptic dysfunction, such as synaptic plasticity inhibition, neurotransmitter imbalance, and synapses loss. Finally, we discuss the alterations in the synapse, synapse formation, and mediators associated with synapse formation during SAE. In this review, we focus on the changes in synapse/synapse formation caused by SAE, which can further understand the synaptic dysfunction associated with neurological impairment in SAE and provide important insights for exploring appropriate therapeutic targets of SAE.

Effects of hydrogen-rich saline in neuroinflammation and mitochondrial dysfunction in rat model of sepsis-associated encephalopathy

Background

Sepsis-associated encephalopathy (SAE) is one of the most common types of sepsis-related organ dysfunction without overt central nervous system (CNS) infection. It is associated with higher mortality, low quality of life, and long-term neurological sequelae in suspected patients. At present there is no specific treatment for SAE rather than supportive therapy and judicious use of antibiotics, which are sometimes associated with adverse effects. Molecular hydrogen (H2) has been reported to play crucial role in regulating inflammatory responses, neuronal injury, apoptosis and mitochondrial dysfunction in adult models of SAE. Here we report the protective effect of hydrogen-rich saline in juvenile SAE rat model and its possible underling mechanism(s).

Materials and methods

Rats were challenged with lipopolysaccharide (LPS) at a dose of 8 mg/kg injected intraperitoneally to induce sepsis and hydrogen-rich saline (HRS) administered 1 h following LPS induction at a dose of 5 ml/kg. Rats were divided into: sham, sham + HRS, LPS and LPS + HRS. At 48 h, rats were sacrificed and Nissl staining for neuronal injury, TUNEL assay for apoptotic cells detection, immunohistochemistry, and ELISA protocol for inflammatory cytokines determination, mitochondrial dysfunction parameters, electron microscopy and western blot analysis were studied to examine the effect of HRS in LPS-induced septic rats.

Results

Rats treated with HRS improved neuronal injury, improvement in rats’ survival rate. ELISA analysis showed decreased TNF-α and IL-1β and increased IL-10 expression levels in the HRS-treated group. Apoptotic cells were decreased after HRS administration in septic rats. The numbers of GFAP and IBA-1positive cells were attenuated in the HRS-treated group when compared to the LPS group. Subsequently, GFAP and IBA-1 immunoreactivity were decreased after HRS treatment. Mitochondrial membrane potential detected by JC-1 dye and ATP content were decreased in septic rats, which were improved after HRS treatment, while release of ROS was increased in the LPS group reverted by HRS treatment, ameliorating mitochondrial dysfunction. Further analysis by transmission electron microscopy showed decreased number of mitochondria and synapses, and disrupted mitochondrial membrane ultrastructure in the LPS group, while HRS administration increased mitochondria and synapses number.

Conclusion

These data demonstrated that HRS can improve survival rate, attenuate neuroinflammation, astrocyte and microglial activation, neuronal injury and mitochondrial dysfunction in juvenile SAE rat model, making it a potential therapeutic candidate in treating paediatric SAE.

Sepsis-Induced Brain Dysfunction: Pathogenesis, Diagnosis, and Treatment

Dysregulated host response to infection, which cause life-threatening organ dysfunction, was defined as sepsis. Sepsis can cause acute and long-term brain dysfunction, namely, sepsis-associated encephalopathy (SAE) and cognitive impairment. SAE refers to changes in consciousness without direct evidence of central nervous system infection. It is highly prevalent and may cause poor outcomes in sepsis patients. Cognitive impairment seriously affects the life quality of sepsis patients and increases the medical burden. The pathogenesis of sepsis-induced brain dysfunction is mainly characterized by the interaction of systemic inflammation, blood-brain barrier (BBB) dysfunction, neuroinflammation, microcirculation dysfunction, and brain dysfunction. Currently, the diagnosis of sepsis-induced brain dysfunction is based on clinical manifestation of altered consciousness along with neuropathological examination, and the treatment is mainly involves controlling sepsis. Although treatments for sepsis-induced brain dysfunction have been tested in animals, clinical treat sepsis-induced brain dysfunction is still difficult. Therefore, we review the underlying mechanisms of sepsis-induced brain injury, which mainly focus on the influence of systemic inflammation on BBB, neuroinflammation, brain microcirculation, and the brain function, which want to bring new mechanism-based directions for future basic and clinical research aimed at preventing or ameliorating brain dysfunction.

Automated Pupillometry as an Assessment Tool for Intracranial Hemodynamics in Septic Patients

Impaired cerebral autoregulation (CA) may increase the risk of brain hypoperfusion in septic patients. Sepsis dysregulates the autonomic nervous system (ANS), potentially affecting CA. ANS function can be assessed through the pupillary light reflex (PLR). The aim of this prospective, observational study was to investigate the association between CA and PLR in adult septic patients. Transcranial Doppler was used to assess CA and calculate estimated cerebral perfusion pressure (eCPP) and intracranial pressure (eICP). An automated pupillometer (AP) was used to record Neurological Pupil Index (NPi), constriction (CV) and dilation (DV) velocities. The primary outcome was the relationship between AP-derived variables with CA; the secondary outcome was the association between AP-derived variables with eCPP and/or eICP. Among 40 included patients, 21 (53%) had impaired CA, 22 (55%) had low eCPP (<60 mmHg) and 15 (38%) had high eICP (>16 mmHg). DV was lower in patients with impaired CA compared to others; DV predicted impaired CA with area under the curve, AUROC= 0.78 [95% Confidence Interval, CI 0.63−0.94]; DV < 2.2 mm/s had sensitivity 85% and specificity 69% for impaired CA. Patients with low eCPP or high eICP had lower NPi values than others. NPi was correlated with eCPP (r = 0.77, p < 0.01) and eICP (r = −0.87, p < 0.01). Automated pupillometry may play a role to assess brain hemodynamics in septic patients.

Clinical Features and Factors Associated With Sepsis-Associated Encephalopathy in Children: Retrospective Single-Center Clinical Study

Background

Sepsis-associated encephalopathy (SAE) is a common complication in septic patients with a higher ICU and hospital mortality in adults and poorer long-term outcomes. Clinical presentation may range from mild confusion to convulsions and deep coma; however, little is known about SAE in children. We aimed to retrospectively analyze the data for children with sepsis, to illustrate the epidemiology, performance, and adverse outcome, and to evaluate the association between risk factors and SAE in children.

Methods

All children with sepsis who were admitted to the Department of Pediatrics, Guangdong Provincial People's Hospital, Guangzhou, Guangdong, China from January 2010 to December 2020 were retrospectively analyzed.

Results

A total of 210 patients with sepsis were retrospectively assigned to the SAE and non-SAE groups, of which 91 (43.33%) were diagnosed with SAE with a mortality of 6.70% (14/210). Significant differences were observed in the level of white blood platelet, platelets, international normalized ratio, prothrombin time, activated partial thromboplastin time, total protein, Ccr, UREA, blood urea nitrogen, alanine transaminase, aspartate transaminase, creatine kinase, creatine kinase isoenzymes, lactate dehydrogenase, procalcitonin, and lactic acid (p < 0.05). In the risk assessment scales, significant differences were observed in the modified Glasgow Coma score, PCIS, Pediatric Logistic Organ Dysfunction Score 2 (PELOD-2), Pediatric Sequential Organ Failure Assessment Score, and Pediatric Risk of Mortality III (p < 0.05). The incidence of septic shock, acute kidney disease, liver dysfunction, and coagulation disorder were higher in the SAE group (p < 0.05). The mechanical ventilation time ([6.57 d ± 16.86 d] vs. [2.05 d ± 5.79 d]; p < 0.001), CRRT time ([1.74 d ± 6.77 d] vs. [0.11 d ± 0.63 d]; p < 0.001), ICU stay time ([299.90 h ± 449.50 h] vs. [177.67 h ± 245.36 h]); p < 0.001 was longer than that of non-SAE. Both the PCT, Ca²⁺, septic shock, PELOD-2, and midazolam were identified as independent risk factors, and fentanyl was a protective factor for SAE in pediatric patients (p < 0.05). The main clinical neurological symptoms consisted of agitation, hypnosia, hypnosis alternates agitated, anterior fontanelle full/bulging/high tension, coma, muscle hypertonia, muscle hypotonia, hyperreflexia, focal seizure, and generalized seizure.

Conclusions

The incidence of SAE in children was found high and the prognosis poor. In this retrospective study, the identified patients were more susceptible to SAE, with an inflammatory storm with hypocalcemia or septic shock. The use of midazolam will increase the occurrence of SAE, whereas fentanyl will reduce the incidence of SAE, and PELOD-2 may predict the occurrence of SAE.

Pathogenesis of sepsis-associated encephalopathy: more than blood-brain barrier dysfunction

Sepsis-associated encephalopathy is a common neurological complication of sepsis and is responsible for higher mortality and poorer long-term outcomes in septic patients. Sepsis-associated encephalopathy symptoms can range from mild delirium to deep coma, which occurs in up to 70% of patients in intensive care units. The pathological changes in the brain associated with sepsis include cerebral ischaemia, cerebral haemorrhage, abscess and progressive multifocal necrotic leukoencephalopathy. Several mechanisms are involved in the pathogenesis of sepsis-associated encephalopathy, such as blood-brain barrier dysfunction, cerebral blood flow impairment, glial cell activation, leukocyte transmigration, and neurotransmitter disturbances. These events are interrelated and influence each other, therefore they do not act as independent factors. This review is focused on new evidence showing the pathological process of sepsis-associated encephalopathy.

Prediction of Medical Conditions Using Machine Learning Approaches: Alzheimer’s Case Study

Alzheimer’s Disease (AD) is a highly prevalent condition and most of the people suffering from it receive the diagnosis late in the process. The diagnosis is currently established following an evaluation of the protein biomarkers in cerebrospinal fluid (CSF), brain imaging, cognitive tests, and the medical history of the individuals. While diagnostic tools based on CSF collections are invasive, the tools used for acquiring brain scans are expensive. Taking these into account, an early predictive system, based on Artificial Intelligence (AI) approaches, targeting the diagnosis of this condition, as well as the identification of lead biomarkers becomes an important research direction. In this survey, we review the state-of-the-art research on machine learning (ML) techniques used for the detection of AD and Mild Cognitive Impairment (MCI). We attempt to identify the most accurate and efficient diagnostic approaches, which employ ML techniques and therefore, the ones most suitable to be used in practice. Research is still ongoing to determine the best biomarkers for the task of AD classification. At the beginning of this survey, after an introductory part, we enumerate several available resources, which can be used to build ML models targeting the diagnosis and classification of AD, as well as their main characteristics. After that, we discuss the candidate markers which were used to build AI models with the best results in terms of diagnostic accuracy, as well as their limitations.

Brain Epitranscriptomic Analysis Revealed Altered A-to-I RNA Editing in Septic Patients

Recent studies suggest that RNA editing is associated with impaired brain function and neurological and psychiatric disorders. However, the role of A-to-I RNA editing during sepsis-associated encephalopathy (SAE) remains unclear. In this study, we analyzed adenosine-to-inosine (A-to-I) RNA editing in postmortem brain tissues from septic patients and controls. A total of 3024 high-confidence A-to-I RNA editing sites were identified. In sepsis, there were fewer A-to-I RNA editing genes and editing sites than in controls. Among all A-to-I RNA editing sites, 42 genes showed significantly differential RNA editing, with 23 downregulated and 19 upregulated in sepsis compared to controls. Notably, more than 50% of these genes were highly expressed in the brain and potentially related to neurological diseases. Notably, cis-regulatory analysis showed that the level of RNA editing in six differentially edited genes was significantly correlated with the gene expression, including HAUS augmin-like complex subunit 2 (HAUS2), protein phosphatase 3 catalytic subunit beta (PPP3CB), hook microtubule tethering protein 3 (HOOK3), CUB and Sushi multiple domains 1 (CSMD1), methyltransferase-like 7A (METTL7A), and kinesin light chain 2 (KLC2). Furthermore, enrichment analysis showed that fewer gene functions and KEGG pathways were enriched by edited genes in sepsis compared to controls. These results revealed alteration of A-to-I RNA editing in the human brain associated with sepsis, thus providing an important basis for understanding its role in neuropathology in SAE.

Sepsis-associated brain injury: underlying mechanisms and potential therapeutic strategies for acute and long-term cognitive impairments

Sepsis is a life-threatening organ dysfunction caused by a dysregulated host response to infection. Sepsis causes cerebral dysfunction in the short and long term and induces disruption of the blood–brain barrier (BBB), neuroinflammation, hypoperfusion, and accumulation of amyloid β (Aβ) and tau protein in the brain. White matter changes and brain atrophy can be detected using brain imaging, but unfortunately, there is no specific treatment that directly addresses the underlying mechanisms of cognitive impairments in sepsis. Here, we review the underlying mechanisms of sepsis-associated brain injury, with a focus on BBB dysfunction and Aβ and tau protein accumulation in the brain. We also describe the neurological manifestations and imaging findings of sepsis-associated brain injury, and finally, we propose potential therapeutic strategies for acute and long-term cognitive impairments associated with sepsis. In the acute phase of sepsis, we suggest using antibiotics (such as rifampicin), targeting proinflammatory cytokines, and preventing ischemic injuries and hypoperfusion. In the late phase of sepsis, we suggest targeting neuroinflammation, BBB dysfunction, Aβ and tau protein phosphorylation, glycogen synthase kinase-3 beta (GSK3β), and the receptor for advanced glycation end products (RAGE). These proposed strategies are meant to bring new mechanism-based directions for future basic and clinical research aimed at preventing or ameliorating acute and long-term cognitive impairments in patients with sepsis.

Polarization of Microglia and Its Therapeutic Potential in Sepsis

Sepsis is a life-threatening organ dysfunction caused by a dysregulated host response to infection, leaving the inflammation process without a proper resolution, leading to tissue damage and possibly sequelae. The central nervous system (CNS) is one of the first regions affected by the peripheral inflammation caused by sepsis, exposing the neurons to an environment of oxidative stress, triggering neuronal dysfunction and apoptosis. Sepsis-associated encephalopathy (SAE) is the most frequent sepsis-associated organ dysfunction, with symptoms such as deliriums, seizures, and coma, linked to increased mortality, morbidity, and cognitive disability. However, the current therapy does not avoid those patients’ symptoms, evidencing the search for a more optimal approach. Herein we focus on microglia as a prominent therapeutic target due to its multiple functions maintaining CNS homeostasis and its polarizing capabilities, stimulating and resolving neuroinflammation depending on the stimuli. Microglia polarization is a target of multiple studies involving nerve cell preservation in diseases caused or aggravated by neuroinflammation, but in sepsis, its therapeutic potential is overlooked. We highlight the peroxisome proliferator-activated receptor gamma (PPARγ) neuroprotective properties, its role in microglia polarization and inflammation resolution, and the interaction with nuclear factor-κB (NF-κB) and mitogen-activated kinases (MAPK), making PPARγ a molecular target for sepsis-related studies to come.

Chromogranin A-derived peptide CGA47-66 protects against septic brain injury by reducing blood-brain barrier damage through the PI3K/AKT pathway

CGA_47-66 (Chromofungin, CHR), is a peptide derived from the N-terminus of chromogranin A (CgA), has been proven to inhibit the lipopolysaccharide (LPS)-induced brain injury. However, the underlying mechanism is still unknown. We found that CGA_47-66 exerted a protective effect on cognitive impairment by inhibiting the destruction of the blood-brain barrier (BBB) in the LPS-induced sepsis mice model. In addition, the hCMEC/D3 cell line was used to establish an in vitro BBB model. Under LPS stimulation, CGA_47-66 could significantly alleviate the hyperpermeability of the BBB, the destruction of tight junction proteins, and the rearrangement of F-actin. To investigate the underlying mechanism, we used LY294002, a PI3K inhibitor, which partially reduced the protective effect of CGA_47-66 on the integrity of BBB. Indicating that the PI3K/AKT pathway plays a vital role in the brain-protective function of CGA_47-66, which might be a potential therapeutic target for septic brain injury.

HMGB1 augments cognitive impairment in sepsis-associated encephalopathy by binding to MD-2 and promoting NLRP3-induced neuroinflammation

BACKGROUND

Sepsis-associated encephalopathy (SAE) always manifests with severe inflammatory symptoms and cognitive impairment. High mobility group box 1 (HMGB1) is a pro-inflammatory cytokine. In this study we investigated the role of HMGB1 in SAE.

METHODS

An SAE mouse model was established through cecal ligation and puncture surgery and then injected with adenovirus short hairpin RNA (Ad-sh)-HMGB1 or Ad-sh-myeloid differentiation protein (MD-2). The cognitive impairment and pathological injury in mice of different groups were evaluated using the Morris water maze experiment, Y-maze test, tail suspension test, fear conditioning test, and haematoxylin-eosin staining. The expressions of HMGB1 (fully reduced and disulfide (ds)HMGB1), MD-2, and NLRP3 in SAE mice were determined. Then, levels of inflammatory cytokines were measured. The binding relation between HMGB1 and MD-2 was predicted and certified. Additionally, MD-2 was downregulated to verify the role of the binding of HMGB1 and MD-2 in neuroinflammation and cognitive impairment in SAE.

RESULTS

Expressions of HMGB1, MD-2, NLRP3, and inflammatory cytokines were enhanced in the SAE mouse model, which were in parallel with impaired cognitive function. HMGB1 silencing resulted in downregulated NLRP3 expression and alleviated neuroinflammation and cognitive impairment in SAE mice. Mechanically, dsHMGB1 bound to MD-2 to activate NLRP3, thereby exacerbating neuroinflammation and cognitive impairment in SAE mice. The limited binding of HMGB1 and MD-2 downregulated NLRP3 expression to alleviate neuroinflammation and cognitive impairment in SAE mice.

CONCLUSION

HMGB1 was overexpressed in SAE, and dsHMGB1 bound to MD-2 to activate NLRP3 inflammasome, inducing neuroinflammation and cognitive impairment in SAE.

Emerging Trends and Hot Spots in Sepsis-Associated Encephalopathy Research From 2001 to 2021: A Bibliometric Analysis

Study Objectives

To evaluate sepsis-associated encephalopathy (SAE) research and to quantitatively and qualitatively predict research hot spots using bibliometric analysis.

Methods

We extracted relevant publications from the Web of Science Core Collection on July 28, 2021. We investigated the retrieved data by bibliometric analysis (e.g. co-cited and cluster analysis, keyword co-occurrence) using the software CiteSpace and VOSviewer, the Online Analysis Platform of Literature Metrology (http://bibliometric.com/) and Bibliometrix to analyse and predict the trends and hot spots in this field.

Main Results

We identified 1,582 published articles and reviews on SAE from 2001 to 2021. During this period, the number of manuscripts on SAE increased steadily and peaked in 2021. The USA and China were the leading countries that had a critical impact on SAE research. Among all institutions, Vanderbilt University and Pittsburgh University held leading positions and became central in the collaboration network. Among all the journals, Critical Care Medicine published the maximum number of manuscripts in the field of SAE within 20 years. Dal-Pizzol Felipe was the most productive author (61 papers) and received the largest number of citations (930 citations). Co-citation cluster analysis revealed that the most popular terms on SAE in the manner of cluster labels were critical illness, sepsis-associated encephalopathy, polymicrobial sepsis, posterior reversible encephalopathy syndrome, rat brain, intensive care unit, prior sepsis, molecular hydrogen, inflammation drive, metabolic encephalopathies, delirium pathophysiology, and clinical neuroscience. Keyword burst detection indicated that neuroinflammation, blood-brain barrier (BBB) and mitochondria dysfunction were the current research hot spots.

Conclusions

Our study revealed that neuroinflammation, blood-brain barrier, and mitochondria dysfunction had been the research foci of SAE over the past 20 years. These have emerged as the basis for transformation from basic research to clinical application in finding effective methods for the prevention and treatment of SAE.

Neuropsychological Outcome of Critically Ill Patients with Severe Infection

Sepsis and septic shock represent important burdens of disease around the world. Sepsis-associated neurological consequences have a great impact on patients, both in the acute phase and in the long term. Sepsis-associated encephalopathy (SAE) is a severe brain dysfunction that may contribute to long-term cognitive impairment. Its pathophysiology recognizes the following two main mechanisms: neuroinflammation and hemodynamic impairment. Clinical manifestations include different forms of altered mental status, from agitation and restlessness to delirium and deep coma. A definite diagnosis is difficult because of the absence of specific radiological and biological criteria; clinical management is restricted to the treatment of sepsis, focusing on early detection of the infection source, maintenance of hemodynamic homeostasis, and avoidance of metabolic disturbances or neurotoxic drugs.

Overexpression of Foxc1 ameliorates sepsis‑associated encephalopathy by inhibiting microglial migration and neuroinflammation through the IκBα/NF‑κB pathway

Sepsis-associated encephalopathy (SAE) is a common and severe complication of sepsis. The cognitive dysfunction that ensues during SAE has been reported to be caused by impairments of the hippocampus. Microglia serves a key role in neuroinflammation during SAE through migration. Forkhead box C1 (Foxc1) is a member of the forkhead transcription factor family that has been found to regulate in cell migration. However, the role of Foxc1 in neuroinflammation during SAE remains unknown. In the present study, the mechanistic role of Foxc1 on microglial migration, neuroinflammation and neuronal apoptosis during the occurrence of cognitive dysfunction in SAE was investigated. A microglia-mediated inflammation model was induced by LPS in BV-2 microglial cells in vitro, whilst a SAE-related cognitive impairment model was established in mice using cecal ligation and perforation (CLP) surgery. Cognitive function in mice was evaluated using the Morris Water Maze (MWM) trial. Lipopolysaccharide (LPS) treatment was found to trigger BV-2 cell migration, inflammation and neuronal apoptosis. In addition, CLP surgery induced cognitive injury, which was indicated by longer latencies and shorter dwell times in the goal quadrant compared with those in the Sham group in the MWM trial. LPS treatment or CLP induction decreased the expression of Foxc1 and inhibitor of NF-κB (IκΒα) whilst increasing that of p65, IL-1β and TNF-α. After Foxc1 was overexpressed, the cognitive dysfunction of mice that underwent CLP surgery was improved, with the expression of IκBα also increased, microglial cell migration, the expression of p65, IL-1β and TNF-α and neuronal apoptosis were all decreased in vivo and in vitro, which were in turn reversed by the inhibition of IκBα in vitro. Overall, these results suggest that the overexpression of Foxc1 inhibited microglial migration whilst suppressing the inflammatory response and neuronal apoptosis by regulating the IκBα/NF-κB pathway, thereby improving cognitive dysfunction during SAE.

Neutrophil extracellular traps and organ dysfunction in sepsis

Sepsis is a clinical syndrome resulting from infection followed by inflammation and is one of the significant causes of mortality worldwide. The underlying reason is the host's uncontrolled inflammatory response due to an infection led to multiple organ dysfunction/failure. Neutrophils, an innate immune cell, are forerunners to reach the site of infection/inflammation for clearing the infection and resolute the inflammation during sepsis. A relatively new neutrophil effector function, neutrophil extracellular traps (NETs), have been demonstrated to kill the pathogens by releasing DNA decorated with histone and granular proteins. A growing number of pieces of shreds of evidence suggest that unregulated incidence of NETs have a significant influence on the pathogenesis of sepsis-induced multiple organ damage, including arterial hypotension, hypoxemia, coagulopathy, renal, neurological, and hepatic dysfunction. Thus, excessive production and improper resolution of NETs are of significant therapeutic value in combating sepsis-induced multiple organ failure. The purpose of this review is intended to highlight the role of NETs in sepsis-induced organ failure. Furthermore, the current status of therapeutic strategies to intersect the harmful effects of NETs to restore organ functions is discussed.

Kynurenic Acid and Its Synthetic Derivatives Protect Against Sepsis-Associated Neutrophil Activation and Brain Mitochondrial Dysfunction in Rats

Background and Aims

The systemic host response in sepsis is frequently accompanied by central nervous system (CNS) dysfunction. Evidence suggests that excessive formation of neutrophil extracellular traps (NETs) can increase the permeability of the blood–brain barrier (BBB) and that the evolving mitochondrial damage may contribute to the pathogenesis of sepsis-associated encephalopathy. Kynurenic acid (KYNA), a metabolite of tryptophan catabolism, exerts pleiotropic cell-protective effects under pro-inflammatory conditions. Our aim was to investigate whether exogenous KYNA or its synthetic analogues SZR-72 and SZR-104 affect BBB permeability secondary to NET formation and influence cerebral mitochondrial disturbances in a clinically relevant rodent model of intraabdominal sepsis.

Methods

Sprague–Dawley rats were subjected to fecal peritonitis (0.6 g kg^-1 ip) or a sham operation. Septic animals were treated with saline or KYNA, SZR-72 or SZR-104 (160 µmol kg^-1 each ip) 16h and 22h after induction. Invasive monitoring was performed on anesthetized animals to evaluate respiratory, cardiovascular, renal, hepatic and metabolic parameters to calculate rat organ failure assessment (ROFA) scores. NET components (citrullinated histone H3 (CitH3); myeloperoxidase (MPO)) and the NET inducer IL-1β, as well as IL-6 and a brain injury marker (S100B) were detected from plasma samples. After 24h, leukocyte infiltration (tissue MPO) and mitochondrial complex I- and II-linked (CI–CII) oxidative phosphorylation (OXPHOS) were evaluated. In a separate series, Evans Blue extravasation and the edema index were used to assess BBB permeability in the same regions.

Results

Sepsis was characterized by significantly elevated ROFA scores, while the increased BBB permeability and plasma S100B levels demonstrated brain damage. Plasma levels of CitH3, MPO and IL-1β were elevated in sepsis but were ameliorated by KYNA and its synthetic analogues. The sepsis-induced deterioration in tissue CI–CII-linked OXPHOS and BBB parameters as well as the increase in tissue MPO content were positively affected by KYNA/KYNA analogues.

Conclusion

This study is the first to report that KYNA and KYNA analogues are potential neuroprotective agents in experimental sepsis. The proposed mechanistic steps involve reduced peripheral NET formation, lowered BBB permeability changes and alleviation of mitochondrial dysfunction in the CNS.

The role of non-invasive brain oximetry in adult critically ill patients without primary brain injury

A primary objective in intensive care and perioperative settings is to promote an adequate supply and delivery of oxygen to tissues and organs, particularly to the brain. Cerebral near infrared spectroscopy (NIRS) is a non-invasive, continuous monitoring technique, that can be used to assess cerebral oxygenation. Using NIRS to monitor cerebral oximetry is not new, and has been in widespread use in neonates and cardiac surgery for decades. In addition, it has become common to see NIRS being used in adult and pediatric cardiac surgery, acute neurological diseases, neurosurgical procedures, vascular surgery, severe trauma and other acute medical diseases. Furthermore, recent evidence suggests a role for NIRS in the perioperative settings; detecting and preventing episodes of cerebral desaturation aiming to reduce the development of post-operative delirium. NIRS is not without its limitations; these include the risk of extra-cranial contamination, spatial limitations and skin blood flow/volume changes, as well being a measure of localized blood oxygenation underneath the sensor. However, NIRS is a non-invasive technique and can, therefore, be used in those patients without indications or justification for invasive brain monitoring; non-neurosurgical procedures such as liver transplantation, major orthopedic surgery and critically illness where the brain is at risk. The aim of this manuscript was to discuss the physical principles of NIRS and to report the current evidence regarding its use in critically ill patients without primary non-anoxic brain injury.

Seizures and Sepsis: A Narrative Review

Patients with sepsis-associated encephalopathy (SAE) can develop convulsive or nonconvulsive seizures. The cytokine storm and the overwhelming systemic inflammation trigger the electric circuits that promote seizures. Several neurologic symptoms, associated with this disease, range from mild consciousness impairment to coma. Focal or generalized convulsive seizures are frequent in sepsis, although nonconvulsive seizures (NCS) are often misdiagnosed and prevalent in SAE. In order to map the trigger zone in all patients that present focal or generalized seizures and also to detect NCS, EEG is indicated but continuous EEG (cEEG) is not very widespread; timing, duration, and efficacy of this tool are still unknown. The long-term risk of seizures in survivors is increased. The typical stepwise approach of seizures management begins with benzodiazepines and follows with anticonvulsants up to anesthetic drugs such as propofol or thiopental, which are able to induce burst suppression and interrupt the pathological electrical circuits. This narrative review discusses pathophysiology, clinical presentation, diagnosis and treatment of seizures in sepsis.

Fecal Microbiota Transplantation: A New Therapeutic Attempt from the Gut to the Brain

Gut dysbacteriosis is closely related to various intestinal and extraintestinal diseases. Fecal microbiota transplantation (FMT) is a biological therapy that entails transferring the gut microbiota from healthy individuals to patients in order to reconstruct the intestinal microflora in the latter. It has been proved to be an effective treatment for recurrent Clostridium difficile infection. Studies show that the gut microbiota plays an important role in the pathophysiology of neurological and psychiatric disorders through the microbiota-gut-brain axis. Therefore, reconstruction of the healthy gut microbiota is a promising new strategy for treating cerebral diseases. We have reviewed the latest research on the role of gut microbiota in different nervous system diseases as well as FMT in the context of its application in neurological, psychiatric, and other nervous system-related diseases (Parkinson's disease, Alzheimer's disease, multiple sclerosis, epilepsy, autism spectrum disorder, bipolar disorder, hepatic encephalopathy, neuropathic pain, etc.).