Cognitive decline after sepsis

Distinct post-sepsis induced neurochemical alterations in two mouse strains

Sepsis associated encephalopathy, occurs in 70% of severe septic cases, following which survivors exhibit long-term cognitive impairment or global loss of cognitive function. Currently there is no clearly defined neurochemical basis of septic encephalopathy. Moreover, the lingering neurological complications associated with the severe acute respiratory syndrome CoV 2 (SARS-CoV-2) and the significant worsening in outcomes for those individuals with SARS-Cov-2 following sepsis underscore the need to define factors underlying the susceptibility to acute toxic encephalitis. In this study, differential neurochemical sequelae in response to sepsis (lipopolysaccharide (LPS)-induced endotoxemia and caecal ligation and puncture (CLP)), were evaluated in two inbred mouse strains, known to differ in behaviour, immune profile, and neurotransmitter levels, namely BALB/c and C57BL/6J. It was hypothesized that these strains would differ in sepsis severity, cytokine profile, peripheral tryptophan metabolism and central monoamine turnover. BALB/c mice exhibited more pronounced sickness behavioural scores, hypothermia, and significant upregulation of cytokines in the LPS model relative to C57BL/6J mice. Increased plasma kynurenine/tryptophan ratio, hippocampal serotonin and brainstem dopamine turnover were evident in both strains, but the magnitude was greater in BALB/c mice. In addition, CLP significantly enhanced kynurenine levels and hippocampal serotonergic and dopaminergic neurotransmission in C57BL/6J mice. Overall, these studies depict consistent changes in kynurenine, serotonin, and dopamine post sepsis. Further evaluation of these monoamines in the context of septic encephalopathy and cognitive decline is warranted. Moreover, these data suggest the continued evaluation of altered peripheral kynurenine metabolism as a potential blood-based biomarker of sepsis.

Non-hepatic Hyperammonemia: A Potential Therapeutic Target for Sepsis-associated Encephalopathy

Sepsis-Associated Encephalopathy (SAE) is a common complication in the acute phase of sepsis, and patients who develop SAE have a higher mortality rate, longer hospital stay, and worse quality of life than other sepsis patients. Although the incidence of SAE is as high as 70% in sepsis patients, no effective treatment is available for this condition. To develop an effective treatment for SAE, it is vital to explore its pathogenesis. It is known that hyperammonemia is a possible factor in the pathogenesis of hepatic encephalopathy as ammonia is a potent neurotoxin. Furthermore, our previous studies indicate that non-hepatic hyperammonemia seems to occur more often in sepsis patients; it was also found that >50% of sepsis patients with non-hepatic hyperammonemia exhibited encephalopathy and delirium. Substatistical analyses indicate that non-hepatic hyperammonemia is an independent risk factor for SAE. This study updates the definition, clinical manifestations, and diagnosis of SAE; it also investigates the possible treatment options available for non-hepatic hyperammonemia in patients with sepsis and the mechanisms by which non-hepatic hyperammonemia causes encephalopathy.

Diabetes Exacerbates Sepsis-Induced Neuroinflammation and Brain Mitochondrial Dysfunction

Sepsis is a life-threatening organ dysfunction, which demands notable attention for its treatment, especially in view of the involvement of immunodepressed patients, as the case of patients with diabetes mellitus (DM), who constitute a population susceptible to develop infections. Thus, considering this endocrine pathology as an implicatory role on the immune system, the aim of this study was to show the relationship between this disease and sepsis on neuroinflammatory and neurochemical parameters. Levels of IL-6, IL-10, brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF), and mitochondrial respiratory chain complexes were evaluated in the hippocampus and prefrontal cortex 24 h after sepsis by cecal ligation and perforation (CLP) in Wistar rats induced to type 1 diabetes by alloxan (150 mg/kg). It was verified that diabetes implied immune function after 24 h of sepsis, since it contributed to the increase of the inflammatory process with higher production of IL-6 and decreased levels of IL-10 only in the hippocampus. In the same brain area, a several decrease in NGF level and activity of complexes I and II of the mitochondrial respiratory chain were observed. Thus, diabetes exacerbates neuroinflammation and results in mitochondrial impairment and downregulation of NGF level in the hippocampus after sepsis.

Caffeine Citrate Protects Against Sepsis-Associated Encephalopathy and Inhibits the UCP2/NLRP3 Axis in Astrocytes

Sepsis-associated encephalopathy (SAE) is a diffuse brain dysfunction without overt central nervous system infection. Caffeine citrate has therapeutic effect on different brain diseases, while its role in SAE remains unclear. The expression levels of interleukin (IL)-18 and IL-1β were upregulated in the cerebrospinal fluid of the subjects. In this study, a rat model of SAE was established by cecal ligation and puncture. Caffeine citrate inhibited SAE-induced neuronal apoptosis and astrocytic activation, decreased reactive oxygen species (ROS) generation, and elevated mitochondrial membrane potential (MMP) level in the cerebral cortex. In vitro, primary astrocytes were isolated from rat cerebral cortex and incubated with lipopolysaccharide (LPS) and interferon-γ (IFN-γ). Caffeine citrate reduced ROS and MMP levels and mitochondrial complex enzyme activities in LPS plus IFN-γ-induced astrocytes. Moreover, caffeine citrate inhibited the activation of nucleotide-binding and oligomerization domain (NOD)-like receptor (NLRP3) inflammasome and decreased the production of IL-1β and IL-18 in vivo and in vitro. Notably, caffeine citrate promoted UCP2 expression in astrocytes. The neuroprotective role of UCP2 has been reported in several experimental brain diseases. These results suggest that caffeine citrate inhibits neuronal apoptosis, astrocytic activation, mitochondrial dysfunction in rat cerebral cortex, thereby alleviating SAE. The protection of caffeine citrate against SAE may be achieved by the UCP2-mediated NLRP3 pathway inhibition in astrocytes.

A crosstalk between gut and brain in sepsis-induced cognitive decline

BACKGROUND

Sepsis is a potentially fatal disease characterized by acute organ failure that affects more than 30 million people worldwide. Inflammation is strongly associated with sepsis, and patients can experience impairments in memory, concentration, verbal fluency, and executive functioning after being discharged from the hospital. We hypothesize that sepsis disrupts the microbiota-gut-brain axis homeostasis triggering cognitive impairment. This immune activation persists during treatment, causing neurological dysfunction in sepsis survivors.

METHODS

To test our hypothesis, adult Wistar rats were subjected to cecal-ligation and perforation (CLP) or sham (non-CLP) surgeries. The animals were subjected to the [11C]PBR28 positron emission tomography (PET)/computed tomography (CT) imaging at 24 h and 10 days after CLP and non-CLP surgeries. At 24 h and 10 days after surgery, we evaluated the gut microbiome, bacterial metabolites, cytokines, microglia, and astrocyte markers. Ten days after sepsis induction, the animals were subjected to the novel object recognition (NOR) and the Morris water maze (MWM) test to assess their learning and memory.

RESULTS

Compared to the control group, the 24-h and 10-day CLP groups showed increased [11C]PBR28 uptake, glial cells count, and cytokine levels in the brain. Results show that sepsis modulates the gut villus length and crypt depth, alpha and beta microbial diversities, and fecal short-chain fatty acids (SCFAs). In addition, sepsis surviving animals showed a significant cognitive decline compared with the control group.

CONCLUSIONS

Since several pharmacological studies have failed to prevent cognitive impairment in sepsis survivors, a better understanding of the function of glial cells and gut microbiota can provide new avenues for treating sepsis patients.

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.

Critical role of acute hypoxemia on the cognitive impairment after severe COVID-19 pneumonia: a multivariate causality model analysis

Background

A high proportion of coronavirus disease 2019 (COVID-19) survivors may develop long-term cognitive impairment. We aimed to develop a multivariate causal model exposing the links between COVID-19-associated biomarkers, illness-related variables, and their effects on cognitive performance.

Methods

In this prospective study, we assess the potential drivers for the development of cognitive impairment in patients with severe COVID-19 pneumonia aged ≥ 18 years at 6-month follow-up after hospital discharge, using the Montreal Cognitive Assessment (MoCA). Patients with pre-existing cognitive impairment were excluded. Laboratory results at hospital admission were clustered by principal component analysis (PCA) and included in a path analysis model evaluating the causal relationship between age, comorbidities, hypoxemia, invasive mechanical ventilation (IMV) requirement, in-hospital delirium, and cognitive performance.

Results

We studied 92 patients: 54 (58.7%) men and 38 (41.3%) women, with median age of 50 years (interquartile range 42–55), among whom 50 (54.4%) tested positive for cognitive impairment at 6-month follow-up. Path analysis revealed a direct link between the thrombo-inflammatory component of PCA (C-reactive protein, fibrinogen, and neutrophils) and hypoxemia severity at hospital admission. Our model showed that low PaO₂/FiO₂ ratio values, unlike the thrombo-inflammatory component, had a direct effect on cognitive performance, independent from age, in-hospital delirium, and invasive mechanical ventilation.

Conclusion

In this study, biomarkers of thrombo-inflammation in COVID-19 and low PaO₂/FiO₂ had a negative effect on cognitive performance 6 months after hospital discharge. These results highlight the critical role of hypoxemia as a driver for impaired cognition in the mid-term.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10072-021-05798-8.

Prognostic factors for late death in septic shock survivors: a multi-center, prospective, registry-based observational study

Septic shock patients who survive past the acute period are associated with an increased risk of long-term mortality. However, factors for predicting late death remain unclear. We aimed to investigate the prognostic factors associated with late mortality in septic shock patients with 28-day survival after admission. This retrospective observational study used a prospective, multi-center registry of septic shock patients between October 2015 and December 2019 involving 12 emergency departments (EDs) from the Korean Shock Society. Adult septic shock patients visiting the ED with 28-day survival after admission were included. Among 4624 septic shock patients, 3588 (77.6%) who survived past day 28 were analyzed. The 90-day mortality rate was 14.2%. Non-survivors were older (66.8 vs. 68.9 years; p = 0.032) and had higher lactate levels (3.7 vs. 4.0 mmol/L; p = 0.028) than survivors. Pulmonary and hepatobiliary infections and a history of malignancy (27.7 vs. 57.5%; p < 0.001) were more frequent in the non-survivor group than in the survivor group. Independent risk factors for late death on multivariate regression analysis were age; malignancy; and hemoglobin, blood urea nitrogen, and albumin levels. The length of intensive care unit stay and Sequential Organ Failure Assessment score were independently associated with late death. Approximately, one-seventh of septic shock patients who survived past day 28 of admission died by day 90. Physicians must pay attention to survivors with these risk factors during the post-acute period as they have an increased mortality risk.

Oxidative stress-related circulating miRNA-27a is a potential biomarker for diagnosis and prognosis in patients with sepsis

Background

Oxidative stress plays a critical role on the processes of sepsis, and several microRNAs have been identified that may regulate the occurrence of oxidative stress. However, the relation between oxidative stress-related microRNA 27a (miR-27a) and sepsis is unknown. The present study aimed to determine the value of circulating miR-27a for the diagnosis and prognosis of sepsis.

Methods

This retrospective study included 23 patients with sepsis and 25 without sepsis treated at the emergency intensive care unit (EICU) or our institution between January 2019 and January 2020. Levels of circulating miR-27a and levels of oxidative stress-related indicators were measured and compared between sepsis and non-sepsis patients. Receiver operating characteristic (ROC) curve analysis was used to determine diagnostic efficiency of miR-27a.

Results

Circulating miR-27a levels in sepsis patients were higher than those in non-sepsis patients (p < 0.05), and levels were significantly higher in patients that died than those that lived (p < 0.05). In patients with sepsis, circulating miR-27a level was positively correlated with serum malondialdehyde (MDA) level (rs = 0.529, p = 0.007), and negatively correlated with serum glutathione peroxidase (GSH-Px) level (rs = − 0.477, p = 0.016). No significant correlation was observed between circulating miR-27a and serum superoxide dismutase (SOD) in sepsis patients (rs = − 0.340, p = 0.096). The area under the ROC curve (AUC) of miR-27a level for prediction of sepsis was 0.717 (p = 0.009) and for 28-day mortality was 0.739 (p = 0.003).

Conclusions

This study showed that circulating miR-27a level is correlated with oxidative stress and mortality in patients with sepsis, and may serve as a potential non-invasive molecular biomarker.

Postmortem Evidence of Brain Inflammatory Markers and Injury in Septic Patients: A Systematic Review

OBJECTIVES

Sepsis is a life-threatening organ dysfunction caused by a host's unregulated immune response to eliminate the infection. After hospitalization, sepsis survivors often suffer from long-term impairments in memory, attention, verbal fluency, and executive functioning. To understand the effects of sepsis and the exacerbated peripheral inflammatory response in the brain, we asked the question: What are the findings and inflammatory markers in the brains of deceased sepsis patients? To answer this question, we conducted this systematic review by the recommendations of Preferred Reporting Items for Systematic Reviews and Meta-Analyses.

DATA SOURCES

Relevant studies were identified by searching the PubMed/National Library of Medicine, PsycINFO, EMBASE, Bibliographical Index in Spanish in Health Sciences, Latin American and Caribbean Health Sciences Literature, and Web of Science databases for peer-reviewed journal articles published on April 05, 2021.

STUDY SELECTION

A total of 3,745 articles were included in the primary screening; after omitting duplicate articles, animal models, and reviews, 2,896 articles were selected for the study. These studies were selected based on the title and abstract, and 2,772 articles were still omitted based on the exclusion criteria.

DATA EXTRACTION

The complete texts of the remaining 124 articles were obtained and thoroughly evaluated for the final screening, and 104 articles were included.

DATA SYNTHESIS

The postmortem brain had edema, abscess, hemorrhagic and ischemic injuries, infarction, hypoxia, atrophy, hypoplasia, neuronal loss, axonal injuries, demyelination, and necrosis.

CONCLUSIONS

The mechanisms by which sepsis induces brain dysfunction are likely to include vascular and neuronal lesions, followed by the activation of glial cells and the presence of peripheral immune cells in the brain.

lncRNA Neat1 regulates neuronal dysfunction post sepsis via stabilization of hemoglobin subunit beta

Sepsis-associated encephalopathy (SAE) is characterized by acute and diffuse brain dysfunction and correlates with long-term cognitive impairments with no targeted therapy. We used a mouse model of sepsis-related cognitive impairment to examine the role of lncRNA nuclear enriched abundant transcript 1 (Neat1) in SAE. We observed that Neat1 expression was increased in neuronal cells from septic mice and that it directly interacts with hemoglobin subunit beta (Hbb), preventing its degradation. The Neat1/Hbb axis suppressed postsynaptic density protein 95 (PSD-95) levels and decreased dendritic spine density. Neat1 knockout mice exhibited decreased Hbb levels, which resulted in increased PSD-95 levels, increased neuronal dendritic spine density, and decreased anxiety and memory impairment. Neat1 silencing via the antisense oligonucleotide GapmeR ameliorated anxiety-like behavior and cognitive impairment post-sepsis. In conclusion, we uncovered a previously unknown mechanism of the Neat1/Hbb axis in regulating neuronal dysfunction, which may lead to a novel treatment strategy for SAE.

Brain innate immune response via miRNA-TLR7 sensing in polymicrobial sepsis

Sepsis-associated encephalopathy (SAE) occurs in sepsis survivors and is associated with breakdown of the blood-brain barrier (BBB), brain inflammation, and neurological dysfunction. We have previously identified a group of extracellular microRNAs (ex-miRNAs), such as miR-146a-5p, that were upregulated in the plasma of septic mice and human, and capable of inducing potent pro-inflammatory cytokines and complements. Here, we established a clinically relevant mouse model of SAE and investigated the role of extracellular miRNAs and their sensor Toll-like receptor 7 (TLR7) in brain inflammation and neurological dysfunction. We observed BBB disruption and a profound neuroinflammatory responses in the brain for up to 14 days post-sepsis; these included increased pro-inflammatory cytokines production, microglial expansion, and peripheral leukocyte accumulation in the CNS. In a battery of neurobehavioral tests, septic mice displayed impairment of motor coordination and neurological function. Sepsis significantly increased plasma RNA and miRNA levels for up to 7 days, such as miR-146a-5p. Exogenously added miR-146a-5p induces innate immune responses in both cultured microglia/astrocytes and the intact brain via a TLR7-dependent manner. Moreover, mice genetically deficient of miR-146a showed reduced accumulation of monocytes and neutrophils in the brain compared to WT after sepsis. Finally, ablation of TLR7 in the TLR7^-/- mice preserved BBB integrity, reduced microglial expansion and leukocyte accumulation, and attenuated GSK3β signaling in the brain, but did not improve neurobehavioral recovery following sepsis. Taken together, these data establish an important role of extracellular miRNA and TLR7 sensing in sepsis-induced brain inflammation.

Ethyl pyruvate, a versatile protector in inflammation and autoimmunity

Ethyl pyruvate (EP) has potent influence on redox processes, cellular metabolism, and inflammation. It has been intensively studied in numerous animal models of systemic and organ-specific disorders whose pathogenesis involves a strong immune component. Here, basic chemical and biological properties of EP are discussed, with an emphasis on its redox and metabolic activity. Further, its influence on myeloid and T cells is considered, as well as on intracellular signaling beyond its effect on immune cells. Also, the effects of EP on animal models of chronic inflammatory and autoimmune disorders are presented. Finally, a possibility to apply EP as a treatment for such diseases in humans is discussed. Scientific papers cited in this review were identified using the PubMed search engine that relies on the MEDLINE database. The reference list covers the most important findings in the field in the past twenty years.

Electroacupuncture Relieves Hippocampal Injury by Heme Oxygenase-1 to Improve Mitochondrial Function

INTRODUCTION

Electroacupuncture (EA) treatment has been demonstrated to have the potential to prevent sepsis-induced hippocampal injury; however, the mechanisms underlying the protective effects of EA against such injury remain unclear. Herein, to elucidate these mechanisms, we constructed a mouse model of lipopolysaccharide (LPS)-induced hippocampal injury to investigate the protection mechanism of EA and to determine whether heme oxygenase-1 (HO-1)-mediated mitochondrial function is involved in the protective effect of EA.

MATERIALS AND METHODS

The sepsis model of hippocampal injury was induced by administering LPS. The Zusanli and Baihui acupoints were stimulated using EA for 30 min once a day, for 5 d before LPS exposure and the first day after administering LPS. Hippocampal injury was investigated by hematoxylin and eosin staining and Nissl staining. HO-1 levels were measured using Western blotting. Mitochondrial metabolism was validated by assessing adenosine triphosphate, superoxide dismutase, malondialdehyde levels, reactive oxygen species production, and mitochondrial respiratory chain activity. Mitochondrial morphology was analyzed by transmission electron microscopy.

RESULTS

EA treatment alleviated neuronal injury, impeded oxidative stress, and improved mitochondrial respiratory function, energy metabolism, and mitochondrial morphology in LPS-exposed mice. In addition, HO-1 knockout aggravated LPS-induced hippocampal injury, aggravated oxidative stress, and reduced mitochondrial respiratory function and aggravated mitochondrial swelling, crest relaxation, and vacuole degeneration. Moreover, EA was unable to reverse the hippocampal damage and mitochondrial dysfunction caused by LPS exposure after HO-1 knockout.

CONCLUSIONS

EA improves LPS-induced hippocampal injury by regulating HO-1-mediated mitochondrial function. Furthermore, HO-1 plays a critical role in maintaining mitochondrial function and resisting oxidative injury.

Biomarkers for sepsis: more than just fever and leukocytosis-a narrative review

A biomarker describes a measurable indicator of a patient's clinical condition that can be measured accurately and reproducibly. Biomarkers offer utility for diagnosis, prognosis, early disease recognition, risk stratification, appropriate treatment (theranostics), and trial enrichment for patients with sepsis or suspected sepsis. In this narrative review, we aim to answer the question, "Do biomarkers in patients with sepsis or septic shock predict mortality, multiple organ dysfunction syndrome (MODS), or organ dysfunction?" We also discuss the role of pro- and anti-inflammatory biomarkers and biomarkers associated with intestinal permeability, endothelial injury, organ dysfunction, blood-brain barrier (BBB) breakdown, brain injury, and short and long-term mortality. For sepsis, a range of biomarkers is identified, including fluid phase pattern recognition molecules (PRMs), complement system, cytokines, chemokines, damage-associated molecular patterns (DAMPs), non-coding RNAs, miRNAs, cell membrane receptors, cell proteins, metabolites, and soluble receptors. We also provide an overview of immune response biomarkers that can help identify or differentiate between systemic inflammatory response syndrome (SIRS), sepsis, septic shock, and sepsis-associated encephalopathy. However, significant work is needed to identify the optimal combinations of biomarkers that can augment diagnosis, treatment, and good patient outcomes.

Electroacupuncture treatment ameliorated the long-term cognitive impairment via activating eNOS/NO pathway and related Aβ downregulation in sepsis-survivor mice

OBJECTIVE

Sepsis is a major challenge in intensive care unit worldwide and the septic survivors are left with long-term cognitive deficits. This work aims to explore the effects of electroacupuncture (EA) on long-term cognitive function and its underlying mechanism in sepsis-survivor mice.

METHODS

Sepsis was induced by cecal ligation and puncture in C57BL/6 male mice. Seven days post-surgery, sepsis-survivor mice were treated with EA or nonacupoint EA for 17 days twice daily. Then, cognitive function was evaluated by Morris water maze task. The hippocampus tissue were collected from the mice at 30 days post-surgery. The level of nitric oxide and the expression of endothelial nitric oxide (eNOS), phospho-eNOS (p-eNOS), and amyloid β-peptide (Aβ) were measured.

RESULTS

Compared with the sham-operated control, sepsis-survivors had significant cognitive deficits evidenced by the increased time of escape latency and reduced crossing number in Morris water maze task, as well as lower NO and p-eNOS level and higher Aβ level. EA treatment at GV20 and ST36 acupoints but not at a nonacupoint improved the cognitive function, increased the NO and p-eNOS level, and decreased Aβ generation; while eNOS inhibitor (l-NAME) undermined the efficacy of EA treatment.

CONCLUSION

In conclusion, repeated EA treatment could ameliorate the long-term cognitive impairment via manipulating the expression of p-eNOS and related Aβ in sepsis-survivor mice.

RhANP attenuates endotoxin-derived cognitive dysfunction through subdiaphragmatic vagus nerve-mediated gut microbiota-brain axis

BACKGROUND

Atrial natriuretic peptide (ANP) secreted from atrial myocytes is shown to possess anti-inflammatory, anti-oxidant and immunomodulatory effects. The aim of this study is to assess the effect of ANP on bacterial lipopolysaccharide (LPS)-induced endotoxemia-derived neuroinflammation and cognitive impairment.

METHODS

LPS (5 mg/kg) was given intraperitoneally to mice. Recombinant human ANP (rhANP) (1.0 mg/kg) was injected intravenously 24 h before and/or 10 min after LPS injection. Subdiaphragmatic vagotomy (SDV) was performed 14 days before LPS injection or 28 days before fecal microbiota transplantation (FMT). ANA-12 (0.5 mg/kg) was administrated intraperitoneally 30 min prior to rhANP treatment.

RESULTS

LPS (5.0 mg/kg) induced remarkable splenomegaly and an increase in the plasma cytokines at 24 h after LPS injection. There were positive correlations between spleen weight and plasma cytokines levels. LPS also led to increased protein levels of ionized calcium-binding adaptor molecule (iba)-1, cytokines and inducible nitric oxide synthase (iNOS) in the hippocampus. LPS impaired the natural and learned behavior, as demonstrated by an increase in the latency to eat the food in the buried food test and a decrease in the number of entries and duration in the novel arm in the Y maze test. Combined prophylactic and therapeutic treatment with rhANP reversed LPS-induced splenomegaly, hippocampal and peripheral inflammation as well as cognitive impairment. However, rhANP could not further enhance the protective effects of SDV on hippocampal and peripheral inflammation. We further found that PGF mice transplanted with fecal bacteria from rhANP-treated endotoxemia mice alleviated the decreased protein levels of hippocampal polyclonal phosphorylated tyrosine kinase receptor B (p-TrkB), brain-derived neurotrophic factor (BDNF) and cognitive impairment, which was abolished by SDV. Moreover, TrkB/BDNF signaling inhibitor ANA-12 abolished the improving effects of rhANP on LPS-induced cognitive impairment.

CONCLUSIONS

Our results suggest that rhANP could mitigate LPS-induced hippocampal inflammation and cognitive dysfunction through subdiaphragmatic vagus nerve-mediated gut microbiota-brain axis.

Blood-Brain Barrier Disruption by Lipopolysaccharide and Sepsis-Associated Encephalopathy

As a complex multicellular structure of the vascular system at the central nervous system (CNS), the blood-brain barrier (BBB) separates the CNS from the system circulation and regulates the influx and efflux of substances to maintain the steady-state environment of the CNS. Lipopolysaccharide (LPS), the cell wall component of Gram-negative bacteria, can damage the barrier function of BBB and further promote the occurrence and development of sepsis-associated encephalopathy (SAE). Here, we conduct a literature review of the direct and indirect damage mechanisms of LPS to BBB and the relationship between these processes and SAE. We believe that after LPS destroys BBB, a large number of inflammatory factors and neurotoxins will enter and damage the brain tissue, which will activate brain immune cells to mediate inflammatory response and in turn further destroys BBB. This vicious circle will ultimately lead to the progression of SAE. Finally, we present a succinct overview of the treatment of SAE by restoring the BBB barrier function and summarize novel opportunities in controlling the progression of SAE by targeting the BBB.

Role of steroids in critically-ill sepsis patients: a review article and literature to review

Sepsis, a life-threatening condition, commonly affecting critically ill patients, is a major cause of death worldwide. It is thus of great importance to determine the optimum management to cure this condition. This review article summarizes the role and effects of corticosteroids in the treatment of sepsis and septic shock, and to determine its mortality benefits. We used PubMed, Google scholar, Scopus, and Embase databases for literature review, and terminologies commonly searched were 'sepsis', 'septic shock', 'therapeutic use' and 'corticosteroids'. In this review article, we reviewed a total of eight different articles being done in last 10 years, relevant to the clinical outcome and effects of corticosteroids. Among those, two demonstrated improved clinical outcomes, two showed both improved clinical outcomes and decreased mortality, three showed increased adverse effects, and the remaining one showed unequivocal results.

Heterogeneity in the Number of Astrocytes in the Central Nervous System after Peritonitis

Sepsis remains a major medical emergency that describes the body's systemic immune response to an infectious process and can lead to end-stage organ dysfunction and death. Clinical studies have introduced the concept of sepsis associated encephalopathy, which seems to have a plethora of cellular and molecular triggers starting from systemic inflammatory cytokines, blood-brain barrier (BBB) rupture, microscopic brain injury, altered cerebral circulation, neurotransmission, or even metabolic dysfunction. The purpose of our study is to reproduce the sepsis model previously described using the cecal ligature and puncture (CLP), and to take a closer look to the acute modifications that occur on cellular level when it comes to the brain-blood-barrier of the mice with systemic inflammation. After a rapid systemic response to peritonitis, we show a heterogeneity in astrocytic response within different cortical structures; hippocampus having the longest change in the number of GFAP+cells, while no difference was seen in the number of cortical astrocytes. With even more increasing roles of astrocytes in different pathologies, the relation between sepsis and astrocytes could prove a valuable in discovering new therapy in sepsis.

(R)-Ketamine attenuates LPS-induced endotoxin-derived delirium through inhibition of neuroinflammation

RATIONALE

(R)-Ketamine produced beneficial effects in a variety of models of inflammatory diseases, including low dose of bacterial lipopolysaccharide (LPS) (0.5-1.0 mg/kg)-induced endotoxemia. LPS-treated mice have been used as animal model of delirium.

OBJECTIVES

We investigated the effects of (R)-ketamine in neuroinflammation and cognitive impairment in rodents after administration of high dose of LPS.

METHODS

LPS (5 mg/kg) or saline was administered intraperitoneally (i.p.) to mice. (R)-Ketamine (10 mg/kg) was administrated i.p. 24 h before and/or 10 min after LPS injection.

RESULTS

LPS (5.0 mg/kg) caused a remarkable splenomegaly and increased plasma levels of pro-inflammatory cytokines [i.e., interleukin (IL-6), IL-17A, and interferon (IFN)-γ]. There were positive correlations between spleen weight and plasma cytokines levels. Furthermore, LPS led to increased levels of pro-inflammatory cytokines in the prefrontal cortex (PFC) and hippocampus. Moreover, LPS impaired the natural and learned behaviors, as demonstrated by a decrease in the number of mice's entries and duration in the novel arm in the Y maze test and an increase in the latency of mice to eat the food in the buried food test. Interestingly, the treatment with (R)-ketamine (twice 24 h before and 10 min after LPS injection) significantly attenuated LPS-induced splenomegaly, central and systemic inflammation, and cognitive impairment.

CONCLUSION

Our results highlighted the importance of combined prophylactic and therapeutic use of (R)-ketamine in the attenuation of LPS-induced systemic inflammation, neuroinflammation, and cognitive impairment in mice. It is likely that (R)-ketamine could be a prophylactic drug for delirium.

Development and Validation of a Nomogram for the Prediction of Hospital Mortality of Patients With Encephalopathy Caused by Microbial Infection: A Retrospective Cohort Study

Background

Hospital mortality is high for patients with encephalopathy caused by microbial infection. Microbial infections often induce sepsis. The damage to the central nervous system (CNS) is defined as sepsis-associated encephalopathy (SAE). However, the relationship between pathogenic microorganisms and the prognosis of SAE patients is still unclear, especially gut microbiota, and there is no clinical tool to predict hospital mortality for SAE patients. The study aimed to explore the relationship between pathogenic microorganisms and the hospital mortality of SAE patients and develop a nomogram for the prediction of hospital mortality in SAE patients.

Methods

The study is a retrospective cohort study. The lasso regression model was used for data dimension reduction and feature selection. Model of hospital mortality of SAE patients was developed by multivariable Cox regression analysis. Calibration and discrimination were used to assess the performance of the nomogram. Decision curve analysis (DCA) to evaluate the clinical utility of the model.

Results

Unfortunately, the results of our study did not find intestinal infection and microorganisms of the gastrointestinal (such as: Escherichia coli) that are related to the prognosis of SAE. Lasso regression and multivariate Cox regression indicated that factors including respiratory failure, lactate, international normalized ratio (INR), albumin, SpO₂, temperature, and renal replacement therapy were significantly correlated with hospital mortality. The AUC of 0.812 under the nomogram was more than that of the Simplified Acute Physiology Score (0.745), indicating excellent discrimination. DCA demonstrated that using the nomogram or including the prognostic signature score status was better than without the nomogram or using the SAPS II at predicting hospital mortality.

Conclusion

The prognosis of SAE patients has nothing to do with intestinal and microbial infections. We developed a nomogram that predicts hospital mortality in patients with SAE according to clinical data. The nomogram exhibited excellent discrimination and calibration capacity, favoring its clinical utility.

Folic acid alleviates the blood brain barrier permeability and oxidative stress and prevents cognitive decline in sepsis-surviving rats

Sepsis is a complication of an infection which imbalance the normal regulation of several organ systems, including the central nervous system (CNS). Evidence points towards inflammation and oxidative stress as major steps associated with brain dysfunction in sepsis. Thus, we investigated the folic acid (FA) effect as an important antioxidant compound on acute brain dysfunction in rats and long term cognitive impairment and survival. Wistar rats were subjected to sepsis by cecal ligation and perforation (CLP) or sham (control) and treated orally with FA (10 mg/kg after CLP) or vehicle (veh). Animals were divided into sham + veh, sham + FA, CLP + veh and CLP + FA groups. Twenty-four hours after surgery, the hippocampus and prefrontal cortex were obtained and assayed for levels of blood brain barrier (BBB) permeability, nitrite/nitrate concentration, myeloperoxidase (MPO) activity, thiobarbituric acid reactive species (TBARS) formation and protein carbonyls. Survival was performed during 10 days after surgery and memory was evaluated. FA reduced BBB permeability, MPO activity in hippocampus and pre frontal cortex in 24 h and lipid peroxidation in hippocampus and improves the survival rate after sepsis. Long term cognitive improvement was verified with FA in septic rats compared with CLP + veh. Our data demonstrates that FA reduces the memory impairment in 10 days after sepsis and mortality in part by decreasing BBB permeability and oxidative stress parameters in the brain.

Protective effects and mechanisms of high-dose vitamin C on sepsis-associated cognitive impairment in rats

Sepsis survivors present long-term cognitive deficits. The present study was to investigate the effect of early administration of high-dose vitamin C on cognitive function in septic rats and explore its possible cerebral protective mechanism. Rat sepsis models were established by cecal ligation and puncture (CLP). Ten days after surgery, the Morris water maze test was performed to evaluate the behavior and cognitive function. Histopathologic changes in the hippocampus were evaluated by nissl staining. The inflammatory cytokines, activities of antioxidant enzymes (superoxide dismutase or SOD) and oxidative products (malondialdehyde or MDA) in the serum and hippocampus were tested 24 h after surgery. The activity of matrix metalloproteinase-9 (MMP-9) and expressions of nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1(HO-1) in the hippocampus were measured 24 h after surgery. Compared with the sham group in the Morris water maze test, the escape latency of sepsis rats was significantly (P = 0.001) prolonged in the navigation test, whereas the frequency to cross the platform and the time spent in the target quadrant were significantly (P = 0.003) reduced. High-dose vitamin C significantly decreased the escape latency (P = 0.01), but increased the time spent in the target quadrant (P = 0.04) and the frequency to cross the platform (P = 0.19). In the CLP+ saline group, the pyramidal neurons were reduced and distributed sparsely and disorderly, the levels of inflammatory cytokines of tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-10 in the serum and hippocampus were significantly increased (P = 0.000), the blood brain barrier (BBB) permeability in the hippocampus was significantly (P = 0.000) increased, the activities of SOD in the serum and hippocampus were significantly (P = 0.000 and P = 0.03, respectively) diminished while the levels of MDA in the serum and hippocampus were significantly (P = 0.007) increased. High-dose vitamin C mitigated hippocampus histopathologic changes, reduced systemic inflammation and neuroinflammation, attenuated BBB disruption, inhibited oxidative stress in brain tissue, and up-regulated the expression of nuclear and total Nrf2 and HO-1. High-dose vitamin C significantly (P < 0.05) decreased the levels of tumor necrosis factor- (TNF)-α, interleukin-6 (IL-6), MDA in the serum and hippocampus, and the activity of MMP-9 in the hippocampus, but significantly (P < 0.05) increased the levels of SOD, the anti-inflammatory cytokine (IL-10) in the serum and hippocampus, and nuclear and total Nrf2, and HO-1 in the hippocampus. In conclusion, high-dose vitamin C can improve cognition impairment in septic rats, and the possible protective mechanism may be related to inhibition of inflammatory factors, alleviation of oxidative stress, and activation of the Nrf2/HO-1 pathway.

Energetic dysfunction in sepsis: a narrative review

Background

Growing evidence associates organ dysfunction(s) with impaired metabolism in sepsis. Recent research has increased our understanding of the role of substrate utilization and mitochondrial dysfunction in the pathophysiology of sepsis-related organ dysfunction. The purpose of this review is to present this evidence as a coherent whole and to highlight future research directions.

Main text

Sepsis is characterized by systemic and organ-specific changes in metabolism. Alterations of oxygen consumption, increased levels of circulating substrates, impaired glucose and lipid oxidation, and mitochondrial dysfunction are all associated with organ dysfunction and poor outcomes in both animal models and patients. The pathophysiological relevance of bioenergetics and metabolism in the specific examples of sepsis-related immunodeficiency, cerebral dysfunction, cardiomyopathy, acute kidney injury and diaphragmatic failure is also described.

Conclusions

Recent understandings in substrate utilization and mitochondrial dysfunction may pave the way for new diagnostic and therapeutic approaches. These findings could help physicians to identify distinct subgroups of sepsis and to develop personalized treatment strategies. Implications for their use as bioenergetic targets to identify metabolism- and mitochondria-targeted treatments need to be evaluated in future studies.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13613-021-00893-7.

Artemisinin improves neurocognitive deficits associated with sepsis by activating the AMPK axis in microglia

Sepsis is life-threatening organ dysfunction due to dysregulated systemic inflammatory and immune response to infection, often leading to cognitive impairments. Growing evidence shows that artemisinin, an antimalarial drug, possesses potent anti-inflammatory and immunoregulatory activities. In this study we investigated whether artemisinin exerted protective effect against neurocognitive deficits associated with sepsis and explored the underlying mechanisms. Mice were injected with LPS (750 μg · kg-1 · d-1, ip, for 7 days) to establish an animal model of sepsis. Artemisinin (30 mg · kg-1 · d-1, ip) was administered starting 4 days prior LPS injection and lasting to the end of LPS injection. We showed that artemisinin administration significantly improved LPS-induced cognitive impairments assessed in Morris water maze and Y maze tests, attenuated neuronal damage and microglial activation in the hippocampus. In BV2 microglial cells treated with LPS (100 ng/mL), pre-application of artemisinin (40 μΜ) significantly reduced the production of proinflammatory cytokines (i.e., TNF-α, IL-6) and suppressed microglial migration. Furthermore, we revealed that artemisinin significantly suppressed the nuclear translocation of NF-κB and the expression of proinflammatory cytokines by activating the AMPKα1 pathway; knockdown of AMPKα1 markedly abolished the anti-inflammatory effects of artemisinin in BV2 microglial cells. In conclusion, atemisinin is a potential therapeutic agent for sepsis-associated neuroinflammation and cognitive impairment, and its effect is probably mediated by activation of the AMPKα1 signaling pathway in microglia.

Innate immune memory mediates increased susceptibility to Alzheimer's disease-like pathology in sepsis surviving mice

Sepsis survivors show long-term impairments, including alterations in memory and executive function. Evidence suggests that systemic inflammation contributes to the progression of Alzheimeŕs disease (AD), but the mechanisms involved in this process are still unclear. Boosted (trained) and diminished (tolerant) innate immune memory has been described in peripheral immune cells after sepsis. However, the occurrence of long-term innate immune memory in the post-septic brain is fully unexplored. Here, we demonstrate that sepsis causes long-lasting trained innate immune memory in the mouse brain, leading to an increased susceptibility to Aβ oligomers (AβO), central neurotoxins found in AD. Hippocampal microglia from sepsis-surviving mice shift to an amoeboid/phagocytic morphological profile when exposed to low amounts of AβO, and this event was accompanied by the upregulation of several pro-inflammatory proteins (IL-1β, IL-6, INF-γ and P2X7 receptor) in the mouse hippocampus, suggesting that a trained innate immune memory occurs in the brain after sepsis. Brain exposure to low amounts of AβO increased microglial phagocytic ability against hippocampal synapses. Pharmacological blockage of brain phagocytic cells or microglial depletion, using minocycline and colony stimulating factor 1 receptor inhibitor (PLX3397), respectively, prevents cognitive dysfunction induced by AβO in sepsis-surviving mice. Altogether, our findings suggest that sepsis induces a long-lasting trained innate immune memory in the mouse brain, leading to an increased susceptibility to AβO-induced neurotoxicity and cognitive impairment.

Protocol for a two-arm pragmatic stepped-wedge hybrid effectiveness-implementation trial evaluating Engagement and Collaborative Management to Proactively Advance Sepsis Survivorship (ENCOMPASS)

BACKGROUND

Sepsis survivors experience high morbidity and mortality, and healthcare systems lack effective strategies to address patient needs after hospital discharge. The Sepsis Transition and Recovery (STAR) program is a navigator-led, telehealth-based multicomponent strategy to provide proactive care coordination and monitoring of high-risk patients using evidence-driven, post-sepsis care tasks. The purpose of this study is to evaluate the effectiveness of STAR to improve outcomes for sepsis patients and to examine contextual factors that influence STAR implementation.

METHODS

This study uses a hybrid type I effectiveness-implementation design to concurrently test clinical effectiveness and gather implementation data. The effectiveness evaluation is a two-arm, pragmatic, stepped-wedge cluster randomized controlled trial at eight hospitals in North Carolina comparing clinical outcomes between sepsis survivors who receive Usual Care versus care delivered through STAR. Each hospital begins in a Usual Care control phase and transitions to STAR in a randomly assigned sequence (one every 4 months). During months that a hospital is allocated to Usual Care, all eligible patients will receive usual care. Once a hospital transitions to STAR, all eligible patients will receive STAR during their hospitalization and extending through 90 days from discharge. STAR includes centrally located nurse navigators using telephonic counseling and electronic health record-based support to facilitate best-practice post-sepsis care strategies including post-discharge review of medications, evaluation for new impairments or symptoms, monitoring existing comorbidities, and palliative care referral when appropriate. Adults admitted with suspected sepsis, defined by clinical criteria for infection and organ failure, are included. Planned enrollment is 4032 patients during a 36-month period. The primary effectiveness outcome is the composite of all-cause hospital readmission or mortality within 90 days of discharge. A mixed-methods implementation evaluation will be conducted before, during, and after STAR implementation.

DISCUSSION

This pragmatic evaluation will test the effectiveness of STAR to reduce combined hospital readmissions and mortality, while identifying key implementation factors. Results will provide practical information to advance understanding of how to integrate post-sepsis management across care settings and facilitate implementation, dissemination, and sustained utilization of best-practice post-sepsis management strategies in other heterogeneous healthcare delivery systems.

TRIAL REGISTRATION

NCT04495946 . Submitted July 7, 2020; Posted August 3, 2020.

The Protective Effect of PK-11195 on Cognitive Impairment in Rats Survived of Polymicrobial Sepsis

Sepsis is an organ dysfunction caused by a host's unregulated response to infection, causing long-term brain dysfunction with microglial activation, the release of inflammatory components, and mitochondrial changes. Neuroinflammation can increase the expression of the 18-kD translocator protein (TSPO) in the mitochondria, leading to the activation of the microglia and the release of inflammatory components. The antagonist PK-11195 can modulate TSPO and reduce microglial activation and cognitive damage presented in an animal model of sepsis. The aim of this was to evaluate the effects of PK-11195 on long-term brain inflammation and cognitive impairment in an animal model of sepsis. Wistar rats, 60 days old, were submitted to cecal ligation and puncture (CLP) surgery, divided into groups control/saline, control/PK-11195, sepsis/saline, and sepsis/PK-11195. Immediately after surgery, the antagonist PK-11195 was administered at a dose of 3 mg/kg. Ten days after CLP surgery, the animals were submitted to behavioral tests and determination of brain inflammatory parameters. The sepsis/saline group presented cognitive damage. However, there was damage prevention in animals that received PK-11195. Besides, the sepsis increased the levels of cytokines and M1 microglia markers and caused oxidative damage. However, PK-11195 had the potential to decrease inflammation. These events show that the modulation of neuroinflammation during sepsis by PK-11195, possibly related to changes in TSPO, improves mitochondrial function in the animals' brains. In conclusion, the antagonist PK-11195 attenuated brain inflammation and prevented cognitive impairment in animals subjected to sepsis.

Quality of life after sepsis and its association with mortality among sepsis survivors in South Korea: A population level cohort study

PURPOSE

This study aimed to investigate the incidence and effect of quality of life (QOL) change in Korean sepsis survivors.

MATERIALS AND METHODS

Using the National Health Insurance claim database of South Korea, we included adult sepsis survivors who were primarily diagnosed with sepsis between 2010 and 2018 and survived for more than 1 year after diagnosis. QOL change was defined using three criteria: decrease in annual income level, newly acquired disability, and increase in underlying comorbidities after sepsis.

RESULTS

A total of 119,660 sepsis survivors were included in the final analysis. Overall, worsening QOL was observed in 92,096 (77.0%) of the survivors. Specifically, compared with that of before sepsis diagnosis, 9778 sepsis survivors (8.2%) had a decrease in annual income level, and 10,648 (8.9%) were newly registered as having a disability. Additionally, 74,528 (62.3%) and 79,142 (66.1%) sepsis survivors showed an increase in the Charlson and Elixhauser comorbidity indices, respectively. Among sepsis survivors, post-sepsis disability and increase in comorbidity indices were associated with a higher risk of 3-year all-cause mortality.

CONCLUSIONS

We found that most sepsis survivors experienced a worsening in their QOL, which was associated with a higher risk of long-term mortality.

Neuroinflammation in Sepsis: Molecular Pathways of Microglia Activation

Frequently underestimated, encephalopathy or delirium are common neurological manifestations associated with sepsis. Brain dysfunction occurs in up to 80% of cases and is directly associated with increased mortality and long-term neurocognitive consequences. Although the central nervous system (CNS) has been classically viewed as an immune-privileged system, neuroinflammation is emerging as a central mechanism of brain dysfunction in sepsis. Microglial cells are major players in this setting. Here, we aimed to discuss the current knowledge on how the brain is affected by peripheral immune activation in sepsis and the role of microglia in these processes. This review focused on the molecular pathways of microglial activity in sepsis, its regulatory mechanisms, and their interaction with other CNS cells, especially with neuronal cells and circuits.

Post-Sepsis Syndrome

Sepsis is both common and costly. Successful implementation of guidelines in the acute care setting has decreased mortality and increased the number of sepsis survivors. However, patients returning to the community continue to experience complications related to sepsis and many are poorly prepared to manage these long-term complications. These long-term complications are collectively referred to as post-sepsis syndrome. The purpose of this review is to increase knowledge about post-sepsis syndrome and to compare post-sepsis syndrome with post-intensive care unit syndrome.

What Animal Models Can Tell Us About Long-Term Psychiatric Symptoms in Sepsis Survivors: a Systematic Review

Lower sepsis mortality rates imply that more patients are discharged from the hospital, but sepsis survivors often experience sequelae, such as functional disability, cognitive impairment, and psychiatric morbidity. Nevertheless, the mechanisms underlying these long-term disabilities are not fully understood. Considering the extensive use of animal models in the study of the pathogenesis of neuropsychiatric disorders, it seems adopting this approach to improve our knowledge of postseptic psychiatric symptoms is a logical approach. With the purpose of gathering and summarizing the main findings of studies using animal models of sepsis-induced psychiatric symptoms, we performed a systematic review of the literature on this topic. Thus, 140 references were reviewed, and most of the published studies suggested a time-dependent recovery from behavior alterations, despite the fact that some molecular alterations persist in the brain. This review reveals that animal models can be used to understand the mechanisms that underlie anxiety and depression in animals recovering from sepsis.

Longitudinal Trajectories of Neurocognitive Functioning in Childhood Acute Lymphoblastic Leukemia

OBJECTIVE

Children with acute lymphoblastic leukemia (ALL) are at risk for neurocognitive deficits, and examining individual variability is essential to understand these risks. This study evaluated latent longitudinal trajectories and risk factors of neurocognitive outcomes in childhood ALL.

METHODS

There were 233 participants with ALL who were enrolled on a phase 3, risk-stratified chemotherapy-only clinical trial (NCT00137111) and who completed protocol-directed neurocognitive assessments [47.6% female, mean (SD) = 6.6 (3.7) years]. Measures of sustained attention, learning/memory, and parent ratings of attention were completed during and after treatment. Longitudinal latent class analyses were used to classify participants into distinct trajectories. Logistic regression was used to identify predictors of class membership.

RESULTS

Within the overall group, attention performance was below age expectations across time (Conners Continuous Performance Test detectability/variability, p < 0.01); memory performance and parent ratings were below expectations at later phases (California Verbal Learning Test learning slope, p < 0.05; Conners Parent Rating Scale, Revised attention/learning, p < 0.05). Most participants (80-89%) had stable neurocognitive profiles; smaller groups showed declining (3-6%) or improving (3-11%) trajectories. Older age (p = 0.020), female sex (p = 0.018), and experiencing sepsis (p = 0.047) were associated with greater attention problems over time. Lower baseline IQ was associated with improved memory (p = 0.035) and fewer ratings of attention problems (p = 0.013) over time.

CONCLUSIONS

Most patients with ALL have stable neurocognitive profiles. Smaller groups have significant impairments shortly after diagnosis or have worsening performance over time. A tiered assessment approach, which includes consideration of individual and clinical risk factors, may be useful for monitoring neurocognitive functioning during treatment and survivorship.

Trajectory of Cognitive Decline After Sepsis

OBJECTIVES

Cognitive impairment is an important consequence of sepsis. We sought to determine long-term trajectories of cognitive function after sepsis.

DESIGN

Prospective study of the Reasons for Geographic and Racial Differences in Stroke cohort.

SETTING

United States.

PATIENTS

Twenty-one thousand eight-hundred twenty-three participants greater than or equal to 45 years, mean (sd) age 64.3 (9.2) years at first cognitive assessment, 30.9% men, and 27.1% Black.

MEASUREMENTS AND MAIN RESULTS

The main exposure was time-dependent sepsis hospitalization. The primary outcome was global cognitive function (Six-Item Screener range, 0-6). Secondary outcomes were incident cognitive impairment (Six-Item Screener score ≤ 4 [impaired] vs ≥5 [unimpaired]), new learning (Consortium to Establish a Registry for Alzheimer Disease Word List Learning range, 0-30), verbal memory (word list delayed recall range, 0-10), and executive function/semantic fluency (animal fluency test range, ≥ 30). Over a median follow-up of 10 years (interquartile range, 6-12 yr), 840 (3.8%) experienced sepsis (incidence 282 per 1,000 person-years). Sepsis was associated with faster long-term declines in Six-Item Screener (-0.02 points per year faster [95% CI, -0.01 to -0.03]; p < 0.001) and faster long-term rates of incident cognitive impairment (odds ratio 1.08 per year [95% CI, 1.02-1.15]; p = 0.008) compared with presepsis slopes. Although cognitive function acutely changed after sepsis (0.05 points [95% CI, 0.01-0.09]; p = 0.01), the odds of acute cognitive impairment (Six-Item Screener ≤ 4) immediately after sepsis was not significant (odds ratio, 0.81 [95% CI, 0.63-1.06]; p = 0.12). Sepsis hospitalization was not associated with acute changes or faster declines in word list learning, word list delayed recall, or animal fluency test.

CONCLUSIONS

Sepsis is associated with accelerated long-term decline in global cognitive function.

Rethinking animal models of sepsis - working towards improved clinical translation whilst integrating the 3Rs

Sepsis is a major worldwide healthcare issue with unmet clinical need. Despite extensive animal research in this area, successful clinical translation has been largely unsuccessful.

We propose one reason for this is that, sometimes, the experimental question is misdirected or unrealistic expectations are being made of the animal model.

As sepsis models can lead to a rapid and substantial suffering – it is essential that we continually review experimental approaches and undertake a full harm:benefit impact assessment for each study. In some instances, this may require refinement of existing sepsis models. In other cases, it may be replacement to a different experimental system altogether, answering a mechanistic question whilst aligning with the principles of reduction, refinement and replacement (3Rs).

We discuss making better use of patient data to identify potentially useful therapeutic targets which can subsequently be validated in preclinical systems. This may be achieved through greater use of construct validity models, from which mechanistic conclusions are drawn. We argue that such models could provide equally useful scientific data as face validity models, but with an improved 3Rs impact. Indeed, construct validity models may not require sepsis to be modelled, per se. We propose that approaches that could support and refine clinical translation of research findings, whilst reducing the overall welfare burden on research animals.

The Neuroprotective Effect of Short Chain Fatty Acids Against Sepsis-Associated Encephalopathy in Mice

Short chain fatty acids (SCFAs) are known to be actively involved in multiple brain disorders, but their roles in sepsis-associated encephalopathy (SAE) remain unclear. Here, we investigated the neuroprotective effects of SCFAs on SAE in mice. Male C57BL/6 mice were intragastrically pretreated with SCFAs for seven successive days, and then subjected to SAE induced by cecal ligation and puncture. The behavioral impairment, neuronal degeneration, and levels of inflammatory cytokines were assessed. The expressions of tight junction (TJ) proteins, including occludin and zoula occludens-1 (ZO-1), cyclooxygenase-2 (COX-2), cluster of differentiation 11b (CD11b), and phosphorylation of JNK and NF-κB p65 in the brain, were measured by western blot and Immunofluorescence analysis. Our results showed that SCFAs significantly attenuated behavioral impairment and neuronal degeneration, and decreased the levels of IL-1β and IL-6 in the brain of SAE mice. Additionally, SCFAs upregulated the expressions of occludin and ZO-1 and downregulated the expressions of COX-2, CD11b, and phosphorylation of JNK and NF-κB p65 in the brain of SAE mice. These findings suggested that SCFAs could exert neuroprotective effects against SAE in mice.

Association between Adherence to Recommended Care and Outcomes for Adult Survivors of Sepsis

Rationale: Postsepsis care recommendations target specific deficits experienced by sepsis survivors in elements such as optimization of medications, screening for functional impairments, monitoring for common and preventable causes of health deterioration, and consideration of palliative care. However, few data are available regarding the application of these elements in clinical practice.Objectives: To quantify the delivery of postsepsis care for patients discharged after hospital admission for sepsis and evaluate the association between receipt of postsepsis care elements and reduced mortality and hospital readmission within 90 days.Methods: We conducted a retrospective chart review of a random sample of patients who were discharged alive after an admission for sepsis (identified from International Classification of Diseases, 10th Revision discharge codes) at 10 hospitals during 2017. We used a structured chart abstraction to determine whether four elements of postsepsis care were provided within 90 days of hospital discharge, per expert recommendations. We used multivariable logistic regression to evaluate the association between receipt of care elements and 90-day hospital readmission and mortality, adjusted for age, comorbidity, length of stay, and discharge disposition.Results: Among 189 sepsis survivors, 117 (62%) had medications optimized, 123 (65%) had screening for functional or mental health impairments, 86 (46%) were monitored for common and preventable causes of health deterioration, and 110 (58%) had care alignment processes documented (i.e., assessed for palliative care or goals of care). Only 20 (11%) received all four care elements within 90 days. Within 90 days of discharge, 66 (35%) patients were readmitted and 33 (17%) died (total patients readmitted or died, n = 82). Receipt of two (odds ratio [OR], 0.26; 95% confidence interval [95% CI], 0.10-0.69) or more (three OR, 0.28; 95% CI, 0.11-0.72; four OR, 0.12; 95% CI, 0.03-0.50) care elements was associated with lower odds of 90-day readmission or 90-day mortality compared with zero or one element documented. Optimization of medications (no medication errors vs. one or more errors; OR, 0.44; 95% CI, 0.21-0.92), documented functional or mental health assessments (physical function plus swallowing/mental health assessments vs. no assessments; OR, 0.14; 95% CI, 0.05-0.40), and documented goals of care or palliative care screening (OR, 0.52; 95% CI, 0.25-1.05; not statistically significant) were associated with lower odds of 90-day readmission or 90-day mortality.Conclusions: In this retrospective cohort study of data from a single health system, we found variable delivery of recommended postsepsis care elements that were associated with reduced morbidity and mortality after hospitalization for sepsis. Implementation strategies to efficiently overcome barriers to adopting recommended postsepsis care may help improve outcomes for sepsis survivors.

The blood-brain barrier dysfunction in sepsis

Sepsis is a life-threatening organ dysfunction triggered by a dysregulated host immune response attempting to eliminate the infection. After hospital discharge, half of the sepsis survivors recover, one-third of the patients die the following year, and one-sixth have a long-term cognitive impairment, including memory dysfunction, anxiety, depression, and post-traumatic stress disorder. The infection triggers the host immune response, and both can cause vascular endothelial damage, interrupting tight junctions proteins; consequently, the blood-brain barrier (BBB) breaks down, allowing and facilitating the entry of peripheral immune cells into the brain, which triggers or exacerbates the activation of glial cells and neuroinflammation. The focus of this review is to identify biochemical abnormalities induced by sepsis, which is associated with BBB dysfunction; provide evidence of biomarkers involved in the tight junction disruption and BBB damage, and draw attention to the role of the BBB as a bridge between systemic infection and brain inflammation.

INT-777 prevents cognitive impairment by activating Takeda G protein-coupled receptor 5 (TGR5) and attenuating neuroinflammation via cAMP/ PKA/ CREB signaling axis in a rat model of sepsis

BACKGROUND

Survivors of sepsis must often endure significant cognitive and behavioral impairments after discharge, but research on the relevant mechanisms and interventions remains lacking. TGR5, a member of the class A GPCR family, plays an important role in many physiological processes, and recent studies have shown that agonists of TGR5 show neuroprotective effects in a variety of neurological disorders. To date, no studies have assessed the effects of TGR5 on neuroinflammatory, cognitive, or behavioral changes in sepsis models.

METHODS

A total of 267 eight-week-old male Sprague-Dawley rats were used in this study. Sepsis was induced via cecal ligation and puncture (CLP). All animals received volume resuscitation. The rats were given TGR5 CRISPR oligonucleotide intracerebroventricularly 48 h before CLP surgery. INT-777 was administered intranasally 1 h after CLP, and the cAMP inhibitor, SQ22536, was administered intracerebroventricularly 1 h after CLP. Survival rate, bodyweight change, and clinical scores were assessed, and neurobehavioral tests, western blot, and immunofluorescence staining were performed. The cognitive function of rats was measured using the Morris water maze during 15-20 days after CLP.

RESULTS

The expression of TGR5 in the rat hippocampus was upregulated, and peaked at 3 days after CLP. The survival rate of rats after CLP was less than 50%, and the growth rate, in terms of weight, was significantly decreased. While INT-777 treatment did not improve these changes, the treatment did reduce the clinical scores of rats at 24 h after CLP. On day 15 and later, the surviving mice completed a series of behavioral tests. CLP rats showed spatial and memory deficits and anxiety-like behaviors, but INT-777 treatment significantly improved these effects. Mechanistically, immunofluorescence analysis showed that INT-777 treatment reduced the number of microglia in the hippocampus, neutrophilic infiltration, and the expression of inflammatory factors after CLP in rats. Moreover, INT-777 treatment significantly increased the expression of TGR5, cAMP, p-PKA, and p-CREB, but downregulated the expression of IL-1β, IL-6, and TNF-α. CRISPR-mediated TGR5 knockdown and SQ22536 treatment abolished the neuroprotective effects of TGR5 activation after CLP.

CONCLUSION

This study demonstrates that INT-777 treatment reduced neuroinflammation and microglial cell activation, but improved cognitive impairment in the experimental sepsis rats. TGR5 has translational potential as a therapeutic target to improve neurological outcomes in sepsis survivors.

Long-Term Functional Outcomes After Sepsis for Adult and Pediatric Critical Care Patients-Protocol for a Systematic Review

Objective: Sepsis is responsible for a massive burden of disease, with a global estimate of 48.9 million cases resulting in approximately 11 million deaths annually. Survivors of sepsis may also experience long-term impairments that can persist for years after hospital discharge. These cognitive, physical and/or psychosocial deficits may contribute to a lower health related quality of life and represent a significant ongoing burden to the individual, the community and the health care system. We aim to systematically review the available evidence on long-term functional and quality of life outcomes after sepsis in children and adults. Data Sources: Medline, EMBASE, and CINAHL will be searched for eligible studies. Study Selection: Studies of adult and pediatric survivors of sepsis who had required admission to intensive care will be included. A minimum 6 month prospective follow up will be required. Accepted outcomes will be any validated measure of health-related quality of life (HRQoL) or functional deficits, using the Post-Intensive Care Syndrome (PICS) framework of cognitive, physical or psychosocial outcomes. Data Extraction: Data extraction will include information related to study characteristics, population characteristics, clinical criteria and outcomes. Data Synthesis: Studies meeting the inclusion criteria will be presented descriptively separated for pediatric and adult age groups. Meta-analysis will be attempted if sufficient primary data from several studies applying the same tests and outcomes are available. The primary outcome is HRQoL after sepsis; secondary outcomes include the functional status at follow-up. Conclusions: This systematic review will define the long-term impact of sepsis survivorship. The data will contribute to informing patient, clinician and stakeholder decisions and guide further research and resource management.