Exploring the impact of dexmedetomidine on short-term outcomes in critically ill sepsis-associated encephalopathy patients.

OBJECTIVE: Dexmedetomidine has demonstrated potential in preclinical medical research as a protective agent against inflammatory injuries and a provider of neuroprotective benefits. However, its effect on the short-term prognosis of patients with sepsis-associated encephalopathy remains unclear. This study aims to explore the underlying value of dexmedetomidine in these patients. PATIENTS AND METHODS: This study enrolled patients with sepsis-associated encephalopathy from the Medical Information Mart for Intensive Care (MIMIC)-IV database, and they were divided into two groups based on dexmedetomidine therapy during hospitalization. Propensity score matching (PSM) and inverse probability of treatment weighting (IPTW) were utilized to balance the inter-group baseline differences. Kaplan-Meier (KM) curves with log-rank test and subgroup analysis were also employed. The primary outcome was 28-day mortality, and the secondary outcomes were in-hospital mortality, intensive care unit (ICU) stay time, hospital stay time, and the incidence of ventilator-associated pneumonia (VAP). RESULTS: After PSM, 1,075 pairs of patients were matched. In contrast to the non-dexmedetomidine cohort, the dexmedetomidine cohort did not exhibit a shortened ICU [4.65 (3.16, 8.55) vs. 6.14 (3.66, 11.04), p<0.001] and hospital stay duration [10.04 (6.55, 15.93) vs. 12.76 (7.92, 19.95), p<0.001], and there was an elevated incidence of VAP [90 (8.4%) vs. 135 (12.6%), p=0.002]. The log-rank test for the KM curves of dexmedetomidine use and 28-day mortality was statistically significant (p<0.001). The results showed that dexmedetomidine was associated with improved 28-day mortality [hazard ratio (HR) 0.46, 95% confidence interval (CI) 0.35-0.61, p<0.001] and in-hospital mortality (HR 0.50, 95% CI 0.37-0.67, p<0.001) after adjusting for various confounders. In the following subgroup analysis, dexmedetomidine infusion was associated with decreased 28-day mortality in most subgroups. CONCLUSIONS: Dexmedetomidine administration was significantly associated with reduced short-term mortality among patients with sepsis-associated encephalopathy in the ICU. However, it also prolonged ICU and hospital stays and increased the incidence of VAP.

Maresin1 improves hippocampal neuroinflammation and cognitive function in septic rats by activating the SLC7A11 / GPX4 ferroptosis signaling pathway.

Sepsis-associated encephalopathy (SAE) is a prevalent complication of sepsis, with hippocampal neuroinflammation playing a crucial role in SAE-induced cognitive impairment. Maresin1 (MaR1), a bioactive docosahexaenoic acid (DHA) metabolite, demonstrates comprehensive anti-inflammatory and neuroprotective attributes. Yet, its protective efficacy against SAE-induced cognitive decline remains unexplored. In this investigation, we implemented a rat SAE model via cecal ligation and puncture (CLP), while lipopolysaccharide (LPS) stimulation of HT22 cells simulated an in vitro SAE model; both models were pre-treated with MaR1. We evaluated rat learning and memory using a water maze, assessed hippocampal neuron damage via Nissl and FJC staining, and observed mitochondrial alterations through TEM. In vivo and in vitro assays gauged levels of Fe2+, MDA, GSH, and SOD. Additionally, Iba1 expression in the hippocampus was examined via immunofluorescence, while SLC7A11 and GPX4 protein expression levels were determined using western blot. Our findings indicated CLP-induced learning and memory impairment in rats, along with heightened ROS, Fe2+, and MDA levels in hippocampal neurons, diminished GSH and SOD levels, and down-regulated ferroptosis-related proteins (GPX4 and SLC7A11). Remarkably, MaR1 treatment attenuated these adverse effects. In LPS-stimulated HT22 cells, MaR1 lowered lipid ROS and bolstered mitochondrial membrane potential. Nonetheless, the ferroptosis inducer Erastin reversed MaR1's protective effects. Transwell experiments further showed MaR1's potential to inhibit microglia activation triggered by ferroptosis in HT22 cells. Consequently, MaR1 may mitigate hippocampal neuroinflammation via activating the SLC7A11/GPX4 ferroptosis signaling pathway, thus ameliorating SAE-related cognitive impairment.

Cuscuta chinensis Lam. Flavonoids (CCLF) alleviate the symptoms of sepsis-associated encephalopathy via PI3K/Nrf2 pathway.

Sepsis-associated encephalopathy (SAE) frequently encounters patients who are in intensive care units and ∼70% of patients with severe systemic infection. However, due to the unclear pathological mechanisms of SAE, the desease-modifying drug is still lack. Here, we aimed to explore whether the flavonoid components extracted from CCL (CCLF) seeds possess protective effects on SAE animals, and systematically evaluate the transcriptomic alteration (in the hippocampus) after CCLF treatment on SAE animals employing RNA sequencing. We observed that CCLF improved the brain's learning and memory abilities and the structural integrity of BBB using cecal ligation and puncture (CLP)-induced SAE animal models, evaluated by behavioral test and tissue examination of animals respectively. RNA sequencing results showed that CCLF treatment reverses SAE-induced transcriptomic alteration in the hippocampus. Moreover, CCLF also dramatically relieved inflammatory (such as TNF-α, IL-2, and IL-6) and oxidative (MDA and SOD activity) stresses, and inhibited SAE-induced neuron apoptosis in brain tissues. More importantly, CCLF restored the PI3K/AKT signaling pathway and then induced the Nrf2 nuclear translocation to drive HO-1 expression both in vitro and in vivo. LY294002, an inhibitor of PI3K, obviously blocked CCLF's functions on anti-apoptosis, anti-inflammation, and anti-oxidation in vivo, demonstrating that CCLF achieves its bioactivities in a PI3K/AKT signaling dependent manner. Altogether, CCLF exhibits remarkable neuro-protective function and may be a promising candidate for further clinical trials for SAE treatment.

4-PBA exerts brain-protective effects against sepsis-associated encephalopathy in a mouse model of sepsis.

BACKGROUND: Neuroinflammation assumes a pivotal role in both the etiological underpinnings and the dynamic progression of sepsis-associated encephalopathy (SAE). The occurrence of cognitive deficits with SAE is associated with neuroinflammation. 4-phenyl butyrate (4-PBA) may control inflammation by inhibiting endoplasmic reticulum stress (ERS). The primary objective of this investigation is to scrutinize the effectiveness of 4-PBA in mitigating neuroinflammation induced by lipopolysaccharides (LPS) and its consequent impact on cognitive function decline. METHODS: LPS-injected mice with SAE and LPS-treated BV2 cell were established to serve as experimental paradigms, both contributing to the investigative framework of the study. Cognitive functions were assessed by behavioral tests. Hippocampal neuronal damage was assessed using Golgi staining and Nissl staining. Quantitative PCR assay and immunofluorescence were used to analyze neuroinflammation. Mitochondrial function was examined using transmission electron microscopy. Protein expression analysis was conducted through the application of western blotting methodology, serving as the investigative approach to elucidate molecular signatures in the experimental framework. Endoplasmic reticulum and mitochondrial calcium flow were detected using flow cytometry. To delve deeper into the mechanistic intricacies, the administration of 4µ8c was employed to selectively impede the IRE1α/Xbp1s pathway, constituting a strategic intervention aimed at elucidating underlying regulatory processes. RESULT: Expression levels of ERS-related proteins exhibited a significant upregulation in hippocampal tissues of LPS-treated mice when compared to wild-type (WT) counterparts. The administration of 4-PBA notably ameliorated memory deficits in LPS-treated mice. Furthermore, 4-PBA treatment was found to alleviate oxidative stress and neuroinflammation. Mechanistically, the IRE1α/Xbp1s-Ca2+ signaling pathway played a crucial role in mediating the beneficial effects of mitigating oxidative stress and maintaining mitochondrial calcium homeostasis, with inhibition of the IRE-related pathway displaying opposing effects. CONCLUSION: Our results suggest that administration of 4-PBA treatment significantly attenuates ERS, alleviates cognitive decline, reduces inflammatory damage, and restores mitochondrial dynamics via the IRE1α/Xbp1s-Ca2+-associated pathway, which provides a new potential therapeutic approach to SAE.

Cannabidiol effect on long-term brain alterations in septic rats: Involvement of PPARγ activation.

Sepsis is a life-threatening condition induced by a deregulated host response to infection. Post-sepsis injury includes long-term cognitive impairment, whose neurobiological mechanisms and effective treatment remain unknown. The present study was designed to determine the potential effects of cannabidiol (CBD) in a sepsis-associated encephalopathy (SAE) model and explore if peroxisome proliferator activated receptor gamma (PPARγ) is the putative mechanism underpinning the beneficial effects. SAE was induced in Wistar rats by cecal ligation and puncture (CLP) or sham (control). CLP rats received vehicle, CBD (10 mg/kg), PPARγ inhibitor (GW9662 - 1 mg/kg), or GW9662 (1 mg/kg) + CBD (10 mg/kg) intraperitoneally for ten days. During this period, the survival rate was recorded, and at the end of 10 days, a memory test was performed, and the prefrontal cortex and hippocampus were removed to verify brain-derived neurotrophic factor (BDNF), cytokines (IL-1ß, IL-6 and IL-10), myeloperoxidase activity, nitrite nitrate concentration, and lipid and protein carbonylation and catalase activity. Septic rats presented cognitive decline and an increase in mortality following CLP. Only CBD alone improved the cognitive impairment, which was accompanied by restoration of BDNF, reduced neuroinflammation, and oxidative stress, mainly in the hippocampus. This study shows that CLP induces an increase in brain damage and CBD has neuroprotective effects on memory impairment and neurotrophins, as well as against neuroinflammation and oxidative stress, and is mediated by PPARγ activation.

Palmatine ameliorated lipopolysaccharide-induced sepsis-associated encephalopathy mice by regulating the microbiota-gut-brain axis.

BACKGROUND: Sepsis-associated encephalopathy (SAE), a common neurological complication from sepsis, is widespread among patients in intensive care unit and is linked to substantial morbidity and mortality rates, thus posing a substantial menace to human health. Due to the intricate nature of SAE's pathogenesis, there remains a dearth of efficacious therapeutic protocols, encompassing pharmaceutical agents and treatment modalities, up until the present time. Palmatine exhibits distinctive benefits in the regulation of inflammation for the improvement of sepsis. Nevertheless, the precise functions of palmatine in treating SAE and its underlying mechanism have yet to be elucidated. PURPOSE: This study aimed to evaluate efficiency of palmatine in SAE mice and its underlying mechanisms. STUDY DESIGN AND METHODS: Behavioral experiments, percent survival rate analysis, histological analysis, immunofluorescence staining, ELISA analysis, were performed to evaluate the efficiency of palmatine in SAE mice. Quantibody® mouse inflammation array glass chip was performed to observe the effects of palmatine on inflammation storm in SAE mice. Real-time quantitative and western blotting analyzes were employed to examine the expression of relevant targets in the Notch1/nuclear factor-kappa B (NF-κB) pathway. Finally, brain tissues metabolomics-based analyzes were performed to detect the differentially expressed metabolites and metabolic pathways. The fecal samples were subjected to microbial 16S rRNA analysis and untargeted metabolomics analysis in order to identify the specific flora and metabolites associated with SAE, thereby further investigating the mechanism of palmatine in SAE mice. RESULTS: Our results showed that palmatine significantly improved nerve function, reduced cell apoptosis in brain tissue, and decreased inflammatory cytokine levels in SAE induced-LPS mice. Meanwhile, our results demonstrate the potential of palmatine in modulating key components of the Notch1/NF-κB pathway, enhancing the expression of tight junction proteins, improving intestinal permeability, promoting the growth of beneficial bacteria (such as Lachnospiraceae_NK4A136_group), inhibiting the proliferation of harmful bacteria (such as Escherichia-Shigella), and mitigating metabolic disorders. Ultimately, these observed effects contribute to the therapeutic efficacy of palmatine in treating SAE. CONCLUSION: The findings of our study have provided confirmation regarding the efficacy of palmatine in the treatment of SAE, thereby establishing a solid foundation for further exploration into SAE therapy and the advancement and investigation of palmatine.

Effect of esketamine pretreatment on acute sepsis-associated encephalopathy.

PURPOSE: Esketamine, the S(+) enantiomer of ketamine, exhibits good anesthetic efficacy and controllability; however, its potential clinical applications, particularly in sepsis-associated encephalopathy (SAE), remain underexplored. SAE involves the development of diffuse brain dysfunction after sepsis, leading to markedly increased sepsis-related disability and mortality. In this study, we investigated the effects of esketamine pretreatment on acute SAE. METHODS: Mice were randomly divided into four groups: control (C, n = 22), acute SAE (L, n = 22), esketamine pretreatment + acute SAE (EL, n = 22), and nuclear factor erythroid 2-related factor 2 (Nrf2) inhibitor (ML385) + esketamine pretreatment + acute SAE (N + EL, n = 22). Acute SAE was established using intraperitoneal (i.p.) injection of lipopolysaccharide (LPS; 10 mg/kg), while controls received equal amounts of saline. The EL group received daily i.p. injections of esketamine (10 mg/kg) for 5 consecutive days, followed by LPS on day 6. The N + EL group received i.p. injections of ML385 (30 mg/kg) 1 h before esketamine pretreatment. The remainder of treatment followed the same protocol as the EL group. Behavioral tests were performed 24 h post-LPS injection, and whole blood and brain tissues were collected for further analysis. RESULTS: Esketamine improved sepsis symptoms, 7-day survival, and spatial cognitive impairment, without altering locomotor activity. Moreover, esketamine reversed the LPS-induced increase in serum S100 calcium-binding protein ß and neuron-specific enolase levels and reduced hippocampal neuroinflammation, oxidative stress, and neuronal apoptosis in the EL group. However, these neuroprotective effects of esketamine were reversed by ML385. CONCLUSION: The results of our study suggest that esketamine pretreatment mitigates acute SAE, highlighting the involvement of the Nrf2/heme oxygenase-1 pathway in mediating its neuroprotective effects.

CD137L Inhibition Ameliorates Hippocampal Neuroinflammation and Behavioral Deficits in a Mouse Model of Sepsis-Associated Encephalopathy.

Anxiety manifestations and cognitive dysfunction are common sequelae in patients with sepsis-associated encephalopathy (SAE). Microglia-mediated inflammatory signaling is involved in anxiety, depression, and cognitive dysfunction during acute infection with bacterial lipopolysaccharide (LPS). However, the molecular mechanisms underlying microglia activation and behavioral and cognitive deficits in sepsis have not been in fully elucidated. Based on previous research, we speculated that the CD137 receptor/ligand system modulates microglia function during sepsis to mediate classical neurological SAE symptoms. A murine model of SAE was established by injecting male C57BL/6 mice with LPS, and cultured mouse BV2 microglia were used for in vitro assays. RT-qPCR, immunofluorescence staining, flow cytometry, and ELISA were used to assess microglial activation and the expression of CD137L and inflammation-related cytokines in the mouse hippocampus and in cultured BV2 cells. In addition, behavioral tests were conducted in assess cognitive performance and behavioral distress. Immunofluorescence and RT-qPCR analyses showed that hippocampal expression of CD137L was upregulated in activated microglia following LPS treatment. Pre-treatment with the CD137L neutralizing antibody TKS-1 significantly reduced CD137L levels, attenuated the expression of M1 polarization markers in microglia, and inhibited the production of TNF-α, IL-1ß, and IL-6 in both LPS-treated mice and BV2 cells. Conversely, stimulation of CD137L signaling by recombinant CD137-Fc fusion protein activated the synthesis and release of pro-inflammatory cytokines in cultures BV2 microglia. Importantly, open field, elevated plus maze, and Y-maze spontaneous alternation test results indicated that TKS-1 administration alleviated anxiety-like behavior and spatial memory decline in mice with LPS-induced SAE. These findings suggest that CD137L upregulation in activated microglia critically contributes to neuroinflammation, anxiety-like behavior, and cognitive dysfunction in the mouse model of LPS-induced sepsis. Therefore, therapeutic modulation of the CD137L/CD137 signaling pathway may represent an effective way to minimize brain damage and prevent cognitive and emotional deficits associated with SAE.

Puerarin prevents sepsis-associated encephalopathy by regulating the AKT1 pathway in microglia.

BACKGROUND: Previous studies have reported that puerarin possesses cardioprotective, vasodilatory, anti-inflammatory, anti-apoptotic, and hypoglycemic properties. However, the impact of puerarin on sepsis-associated encephalopathy (SAE) remains unexplored. In this study, we explored whether puerarin can modulate microglia-mediated neuroinflammation for the treatment of SAE and delved into the underlying mechanisms. METHODS: We established a murine model of SAE through intraperitoneal injection of lipopolysaccharide (LPS). The puerarin treatment group received pretreatment with puerarin. For in vitro experiments, BV2 cells were pre-incubated with puerarin for 2 h before LPS exposure. We employed network pharmacology, the Morris Water Maze (MWM) test, Novel Object Recognition (NOR) test, immunofluorescence staining, enzyme-linked immunosorbent assay (ELISA), Western blotting, and quantitative real-time PCR (qRT-PCR) to elucidate the molecular mechanism of underlying puerarin's effects in SAE treatment. RESULTS: Our findings demonstrate that puerarin significantly reduced the production of inflammatory cytokines (TNF-α and IL-6) in the peripheral blood of LPS-treated mice. Moreover, puerarin treatment markedly ameliorated sepsis-associated cognitive impairment. Puerarin also exhibited inhibitory effects on the release of TNF-α and IL-6 from microglia, thereby preventing hippocampal neuronal cell death. Network pharmacology analysis identified AKT1 as a potential therapeutic target for puerarin in SAE treatment. Subsequently, we validated these results in both in vitro and in vitro experiments. Our study conclusively demonstrated that puerarin reduced LPS-induced phosphorylation of AKT1, with the AKT activator SC79 reversing puerarin's anti-inflammatory effects through the activation of the AKT1 signaling pathway. CONCLUSION: Puerarin exerts an anti-neuroinflammatory effect against SAE by modulating the AKT1 pathway in microglia.

TIPE2 ameliorates neuroinflammation and cognitive impairment in sepsis-associated encephalopathy through regulating RhoA/ROCK2-NF-κB signaling pathway.

Sepsis-associated encephalopathy (SAE) is an acute brain dysfunction induced by systemic inflammation caused by sepsis and is one of the most common types of encephalopathy in intensive care units. Deteriorative neuroinflammation is closely related to the development of brain injury, which often transforms into common pathological manifestations in patients with severe sepsis. Therefore, taking necessary preventive and protective measures for potential brain injury and promptly reducing neuroinflammatory injury is necessary to improve the long-term prognoses of patients. Tumor necrosis factor-α-induced protein 8-like 2 (TIPE2) can play a significant protective role in septic lung injury, but studies on its expression and role in neurological diseases are rare. In the present study, we found that TIPE2 can expressed in microglia and ameliorate brain injury caused by SAE by suppressing neuroinflammation. The RhoA/ROCK2 pathway is the central coordinator of tissue injury response, and the activation of RhoA participates in the lipopolysaccharide-induced activation of the nuclear factor kappa B (NF-κB) signaling pathway. The activation of RhoA and phosphorylation of NF-κB was enhanced after TIPE2 deficiency. Importantly, TIPE2 negatively regulates inflammatory responses in vivo and in vitro and plays a protective role in SAE by inhibiting the activation of RhoA/ROCK2-NF-κB signaling pathways. The ultimate aim of our proposed project is to provide a theoretical basis for the development of a novel strategy for the early prevention and therapy of SAE.

Hydrogen-rich saline regulates NLRP3 inflammasome activation in sepsis-associated encephalopathy rat model.

Sepsis-associated encephalopathy (SAE) is characterised by long-term cognitive impairment and psychiatric illness in sepsis survivors, associated with increased morbidity and mortality. There is a lack of effective therapeutics for SAE. Molecular hydrogen (H2) plays multiple roles in septic diseases by regulating neuroinflammation, reducing oxidative stress parameters, regulating signalling pathways, improving mitochondrial dysfunction, and regulating astrocyte and microglia activation. Here we report the protective effect of hydrogen-rich saline in the juvenile SAE rat model and its possible underlying mechanisms. Rats were injected intraperitoneally with lipopolysaccharide at a dose of 5 mg/kg to induce sepsis; Hydrogen-rich saline (HRS) was administered 1 h after LPS induction at a dose of 5 ml/kg and nigericin at 1 mg/kg 1 h before LPS injection. H&E staining for neuronal damage, TUNEL assay for detection of apoptotic cells, immunofluorescence, ELISA protocol for inflammatory cytokines and 8-OHdG determination and western blot analysis to determine the effect of HRS in LPS-induced septic rats. Rats treated with HRS showed decreased TNF-α and IL-1ß expression levels. HRS treatment enhanced the activities of antioxidant enzymes (SOD, CAT and GPX) and decreased MDA and MPO activities. The number of MMP-9 and NLRP3 positive immunoreactivity cells decreased in the HRS-treated group. Subsequently, GFAP, IBA-1 and CD86 immunoreactivity were reduced, and CD206 increased after HRS treatment. 8-OHdG expression was decreased in the HRS-treated rats. Western blot analysis showed decreased NLRP3, ASC, caspase-1, MMP-2/9, TLR4 and Bax protein levels after HRS treatment, while Bcl-2 expression increased after HRS treatment. These data demonstrated that HRS attenuated neuroinflammation, NLRP3 inflammasome activation, neuronal injury, and mitochondrial damage via NLRP3/Caspase-1/TLR4 signalling in the juvenile rat model, making it a potential therapeutic agent in the treatment of paediatric SAE.

Hydrogen alleviated cognitive impairment and blood‒brain barrier damage in sepsis-associated encephalopathy by regulating ABC efflux transporters in a PPARα-dependent manner.

Hydrogen (H2) can protect against blood‒brain barrier (BBB) damage in sepsis-associated encephalopathy (SAE), but the mechanism is still unclear. We examined whether it is related to PPARα and its regulatory targets, ABC efflux transporters. After injection with DMSO/GW6471 (a PPARα inhibitor), the mice subjected to sham/caecal ligation and puncture (CLP) surgery were treated with H2 for 60 min postoperation. Additionally, bEnd.3 cells were grown in DMSO/GW6471-containing or saline medium with LPS. In addition to the survival rates, cognitive function was assessed using the Y-maze and fear conditioning tests. Brain tissues were stained with TUNEL and Nissl staining. Additionally, inflammatory mediators (TNF-α, IL-6, HMGB1, and IL-1ß) were evaluated with ELISA, and PPARα, ZO-1, occludin, VE-cadherin, P-gp, BCRP and MRP2 were detected using Western blotting. BBB destruction was assessed by brain water content and Evans blue (EB) extravasation. Finally, we found that H2 improved survival rates and brain dysfunction and decreased inflammatory cytokines. Furthermore, H2 decreased water content in the brain and EB extravasation and increased ZO-1, occludin, VE-cadherin and ABC efflux transporters regulated by PPARα. Thus, we concluded that H2 decreases BBB permeability to protect against brain dysfunction in sepsis; this effect is mediated by PPARα and its regulation of ABC efflux transporters.

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.

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.

Role of Imaging Modalities and N-Acetylcysteine Treatment in Sepsis-Associated Encephalopathy.

Sepsis-associated encephalopathy is a severe systemic infection complication. Although early stages involve pathophysiological changes, detection using conventional imaging is challenging. Glutamate chemical exchange saturation transfer and diffusion kurtosis imaging can noninvasively investigate cellular and molecular events in early disease stages using magnetic resonance imaging (MRI). N-Acetylcysteine, an antioxidant and precursor of glutathione, regulates neurotransmitter glutamate metabolism and participates in neuroinflammation. We investigated the protective role of n-acetylcysteine in sepsis-associated encephalopathy using a rat model and monitored changes in brain using magnetic resonance (MR) molecular imaging. Bacterial lipopolysaccharide was injected intraperitoneally to induce a sepsis-associated encephalopathy model. Behavioral performance was assessed using the open-field test. Tumor necrosis factor α and glutathione levels were detected biochemically. Imaging was performed using a 7.0-T MRI scanner. Protein expression, cellular damage, and changes in blood-brain barrier permeability were assessed using western blotting, pathological staining, and Evans blue staining, respectively. Lipopolysaccharide-induced rats showed reduced anxiety and depression after treatment with n-acetylcysteine. MR molecular imaging can identify pathological processes at different disease stages. Furthermore, rats treated with n-acetylcysteine showed increased glutathione levels and decreased tumor necrosis factor α, suggesting enhanced antioxidant capacity and inhibition of inflammatory processes, respectively. Western blot analysis showed reduced expression of nuclear factor kappa B (p50) protein after treatment, suggesting that n-acetylcysteine inhibits inflammation via this signaling pathway. Finally, n-acetylcysteine-treated rats showed reduced cellular damage by pathology and reduced extravasation of their blood-brain barrier by Evans Blue staining. Thus, n-acetylcysteine might be a therapeutic option for sepsis-associated encephalopathy and other neuroinflammatory diseases. Furthermore, noninvasive "dynamic visual monitoring" of physiological and pathological changes related to sepsis-associated encephalopathy was achieved using MR molecular imaging for the first time, providing a more sensitive imaging basis for early diagnosis, identification, and prognosis.

Puerarin protects against sepsis-associated encephalopathy by inhibiting NLRP3/Caspase-1/GSDMD pyroptosis pathway and reducing blood-brain barrier damage.

Puerarin (Pue), an isoflavone compound extracted from Pueraria, has been shown to inhibit inflammation and reduce cerebral edema. The neuroprotective effect of puerarin has attracted much attention in recent years. Sepsis-associated encephalopathy (SAE) is a serious complication of sepsis that causes damage to the nervous system. This study aimed to investigate the effect of puerarin on SAE and elucidate the potential underlying mechanisms. A rat model of SAE was established by cecal ligation and puncture, and puerarin was injected intraperitoneally immediately after the operation. Puerarin was found to improve the survival rate and neurobehavioral score of SAE rats, alleviate symptoms, inhibit the level of brain injury markers NSE and S100ß, and improve the pathological changes in rat brain tissue. Puerarin was also found to inhibit the level of factors related to the classical pathway of pyroptosis, such as NLRP3, Caspase-1, GSDMD, ASC, IL-1ß, and IL-18. Puerarin also reduced the brain water content and penetration of Evan's Blue dye in SAE rats, and reduced the expression of MMP-9. In the in vitro experiments, we further confirmed the inhibitory effect of puerarin on neuronal pyroptosis by establishing a pyroptosis model in HT22 cells. Our findings suggest that puerarin may improve SAE by inhibiting the classical pathway of NLRP3/Caspase-1/GSDMD-mediated pyroptosis and reducing blood-brain barrier damage, thus playing a role in brain protection. Our study may provide a novel therapeutic strategy for SAE.

HC067047 Ameliorates Sepsis-associated Encephalopathy by Suppressing Endoplasmic Reticulum Stress and Oxidative Stress-Induced Pyroptosis in the Hippocampi of Mice.

Sepsis-associated encephalopathy (SAE) is a common neurological complication of sepsis and is characterized by hyperneuroinflammation. NLRP3 inflammasome-mediated pyroptosis can induce an inflammatory cascade response and plays a key role in SAE. TRPV4 is involved in the hyperinflammatory response associated with inflammation; however, whether TRPV4 inhibition might alleviate SAE-related brain damage is still unknown. Therefore, we aimed to investigate the role and mechanism of HC067047, a potent inhibitor of TRPV4, in hyperneuroinflammation and blood-brain barrier (BBB) dysfunction in a lipopolysaccharide (LPS)-induced SAE mouse model. We found that HC067047 administration significantly inhibited the expression of TRPV4 and p-CamkIIα in the hippocampi of SAE mice. Furthermore, HC067047 treatment attenuated LPS-induced endoplasmic reticulum (ER) stress and oxidative stress (OS), thus remarkably preventing NLRP3 inflammasome-mediated pyroptosis, as well as the expression of proinflammatory factors (IL-1ß and IL-18). Additionally, we found that HC067047 selectively prevented pyroptosis in hippocampal cells, mainly the neurons, oligodendrocytes and the resident microglia. The disruption of BBB integrity in SAE mice was also rescued by HC067047 intervention. Thus, we can conclude that the TRPV4 inhibitor HC067047 could protect against hippocampal cell pyroptosis, which might be due to the attenuation of the NLRP3 inflammasome-mediated pyroptosis pathway caused by ER stress and OS. Our findings suggest a potential preventive role for HC067047 in SAE.

Activation of glucagon-like peptide-1 receptor in microglia exerts protective effects against sepsis-induced encephalopathy via attenuating endoplasmic reticulum stress-associated inflammation and apoptosis in a mouse model of sepsis.

Sepsis-induced encephalopathy (SAE) is a detrimental complication in patients with severe sepsis, while there is still no effective treatment. Previous studies have elucidated the neuroprotective effects of glucagon-like peptide-1 receptor (GLP-1R) agonists. However, the role of GLP-1R agonists in the pathological process of SAE is unclear. Here, we found that GLP-1R was up-regulated in the microglia of septic mice. The activation of GLP-1R with Liraglutide could inhibit endoplasmic reticulum stress (ER stress) and associated inflammatory response as well as apoptosis triggered by LPS or tunicamycin (TM) in BV2 cells. In vivo experiments confirmed the benefits of Liraglutide in the regulation of microglial activation, ER stress, inflammation, and apoptosis in the hippocampus of septic mice. Additionally, the survival rate and cognitive dysfunction of septic mice were also improved after Liraglutide administration. Mechanically, cAMP/PKA/CREB signaling is involved in the protection of ER stress-induced inflammation and apoptosis in cultured microglial cells under LPS or TM stimulations. In conclusion, we speculated that GLP-1/GLP-1R activation in microglia might be a potential therapeutic target for the treatment of SAE.

Dexpramipexole ameliorates cognitive deficits in sepsis-associated encephalopathy through suppressing mitochondria-mediated pyroptosis and apoptosis.

OBJECTIVES: This study was aimed at evaluating the effects of dexpramipexole (DPX) - a mitochondrial protectant that sustains mitochondrial function and energy production - on cognitive function in a mouse model of sepsis-associated encephalopathy (SAE) induced by peripheral administration of lipopolysaccharide (LPS) and examining the potential mechanisms. METHODS: C57BL/6 male mice were randomized into one of four treatment protocols: Con+Sal, Con+DPX, LPS+Sal or LPS+DPX. The mice were intraperitoneally (i.p.) injected with LPS or equivalent volumes of normal saline once daily for 3 consecutive days. To evaluate the protective effects of DPX, we administered DPX or normal saline i.p. to the mice once daily for 6 consecutive days. Six mice in each group were decapitated on day 7, and each brain was rapidly removed and separated into two halves for biochemical and histochemical analysis. The remaining surviving mice in each group were subjected to behavioral tests from days 7 to 10. RESULTS: Peripheral administration of LPS to mice led to learning and memory deficits in behavioral tests, which were associated with mitochondrial impairment and ATP depletion in the hippocampus. Repeated DPX treatment protected the mitochondria against LPS-induced morphological and functional impairment; inhibited the activation of the Nod-like receptor pyrin domain-containing 3 (NLRP3) inflammasome-caspase-1-dependent pyroptosis pathway and cytochrome c (Cyt-c)-caspase-3-dependent apoptosis pathway; and attenuated LPS-induced neuroinflammation and cell death in the hippocampus in SAE mice. CONCLUSIONS: Mitochondria-mediated pyroptosis and apoptosis are involved in the pathogenesis of cognitive deficits in a mouse model of SAE and DPX protects mitochondria and suppresses the mitochondria-medicated pyroptosis and apoptosis pathways, and ameliorates LPS-induced neuroinflammation and cognitive deficits. This study provides theoretical evidence supporting DPX for the treatment of SAE.

ß-patchoulene alleviates cognitive dysfunction in a mouse model of sepsis associated encephalopathy by inhibition of microglia activation through Sirt1/Nrf2 signaling pathway.

BACKGROUND: Sepsis associated encephalopathy (SAE) is a common but poorly understood complication during sepsis. Currently, there are no preventive or therapeutic agents available for this neurological disorder. The present study was designed to determine the potential protective effects of ß-patchoulene (ß-PAE) in a mouse model of SAE and explore the putative mechanisms underpinning the beneficial effects. MATERIALS AND METHODS: SAE was induced in C57BL/6 mice by cecal ligation and puncture(CLP). Mice were administrated with ß-PAE or saline by intra-cerebral ventricle(i.c.v) injection immediately after CLP surgery. The inhibitory avoidance tests and open field tests were performed at 24h, 48h and 7days after procedures. Cytokines expression, oxidative parameters, microglia polarization and apoptosis in the brain tissue were assessed. Sirt1, Nrf2, HO-1and cleaved-caspase3 expression in hippocampus was determined by western-blotting. Further, serum cytokines expression and spleen lymphocytes apoptosis were evaluated, and survival study was performed. RESULTS: Septic mice suffered severe cognitive decline following CLP as evidenced by decreased memory latency time and lower frequency of line crossing in the behavioral tests. A high dose of ß-PAE(1mg/kg) improved the cognitive impairment in SAE mice, which was accompanied by reduced cytokines expression and oxidative stress. Immunofluorescence assay showed that ß-PAE inhibited the expression of Iba-1 and iNOS in microglia. The mechanistic study indicated that ß-PAE could promote the nuclear expression of Sirt1/Nrf2 and enhance cytoplasmic HO-1 expression. Furthermore, i.c.v administration of ß-PAE decreased the expression of serum cytokines and apoptosis in the spleen, thus leading to an improved 7-day survival of septic mice. Finally, blockade of Nrf2 activation with ML385 largely mitigated the protective effects of ß-PAE on the cognitive function, neuroinflammation and survival in SAE mice. CONCLUSION: In this study, we found that ß-PAE significantly altered sepsis induced neuroinflammation and microglia activation, thus reversed the cognitive decline and improved the peripheral immune function. The neuroprotective effects were possibly mediated by the activation of Sirt1/Nrf2/HO-1 pathway. ß-PAE might serve as a promising therapeutic agent for SAE prevention and treatment.