Sepsis: developing new alternatives to reduce neuroinflammation and attenuate brain injury

Therapeutically Fine-Tuning Autonomic Nervous System to Treat Sepsis: A New Perspective on the Immunomodulatory Effects of Acupuncture

Recent studies have highlighted the immunomodulatory effects of acupuncture on sepsis and proposed novel non-pharmacological or bioelectronic approaches to managing inflammatory illnesses. Establishing rules for selectively activating sympathetic or vagal nerve-mediated anti-inflammatory pathways using acupuncture has valuable clinical applications. Over the years, studies have revealed the segmental modulatory role of acupuncture in regulating visceral function by targeting the autonomic nervous system (ANS). In this review, we aim to summarize recent findings on acupuncture in treating sepsis, focusing on the underlying ANS mechanism, as well as the rules of acupoint specificity, intensity, frequency, and other parameters utilized in these studies. Mechanistically, the immunomodulatory properties of the sympathetic nervous system have been highlighted. Furthermore, we explore the immunotherapeutic benefits of acupuncture in treating sepsis. A better understanding of the immunoregulatory mechanism of sympathetic nervous system may offer novel approaches for the development of therapeutics to treat or prevent a variety of inflammatory diseases.

Inhibition of sepsis-induced pancreatic injury by leukotriene receptor antagonism via modulation of oxidative injury, and downregulation of inflammatory markers in experimental rats

The purpose of this study is to investigate the effect of montelukast on lipopolysaccharide (LPS)-induced pancreatitis. Adult male Wistar rats were divided into 5 groups: normal control, control montelukast, LPS group, and two LPS + montelukast-treated groups. Acute pancreatitis (AP) was induced by a single dose of LPS (6 mg/kg, i.p.), while montelukast was given in two different doses (10 and 20 mg/kg/day) for 3 consecutive days prior to the injection of LPS. AP was demonstrated by significant increases in serum levels of lactate dehydrogenase (LDH) and pancreatic enzymes lipase and amylase. Proinflammatory response activation was evident by elevated serum levels of nitric oxide (NO) and increased pancreatic concentrations of tumor necrosis factor-α (TNF-α), interleukin-1 (IL-1β), and intercellular adhesion molecule-1 (ICAM-1). The activity of myeloperoxidase (MPO), a neutrophil infiltration marker, has also been increased. Oxidative stress was confirmed by significant increases in the concentrations of lipid peroxides measured as thiobarbituric acid reactive substances (TBARS) and decreases in the concentrations of reduced glutathione (GSH) in the pancreatic tissues of animals treated with LPS. Histological examination confirmed the biochemical alterations. Montelukast treatment reversed all these biochemical indices and histopathological changes that LPS induced. Montelukast reduced the increase in serum levels of lipase, amylase, LDH, total nitrite/nitrate, TNF-α, IL-1β, and ICAM-1. MPO activities and TBARS concentrations were also suppressed while GSH content was increased in pancreatic tissues. These results show that montelukast may be a beneficial pharmacological agent in protection against LPS-induced oxidative pancreatic injury by inhibiting neutrophil infiltration, counteracting oxidative stress, and suppressing inflammatory mediators.

Intranasal Versus Intravenous Dexamethasone to Treat Hospitalized COVID-19 Patients: A Randomized Multicenter Clinical Trial

BACKGROUND

SARS-CoV2 induces flu-like symptoms that can rapidly progress to severe acute lung injury and even death. The virus also invades the central nervous system (CNS), causing neuroinflammation and death from central failure. Intravenous (IV) or oral dexamethasone (DXM) reduced 28 d mortality in patients who required supplemental oxygen compared to those who received conventional care alone. Through these routes, DMX fails to reach therapeutic levels in the CNS. In contrast, the intranasal (IN) route produces therapeutic levels of DXM in the CNS, even at low doses, with similar systemic bioavailability.

AIMS

To compare IN vs. IV DXM treatment in hospitalized patients with COVID-19.

METHODS

A controlled, multicenter, open-label trial. Patients with COVID-19 (69) were randomly assigned to receive IN-DXM (0.12 mg/kg for three days, followed by 0.6 mg/kg for up to seven days) or IV-DXM (6 mg/d for 10 d). The primary outcome was clinical improvement, as defined by the National Early Warning Score (NEWS) ordinal scale. The secondary outcome was death at 28 d between IV and IN patients. Effects of both treatments on biochemical and immunoinflammatory profiles were also recorded.

RESULTS

Initially, no significant differences in clinical severity, biometrics, and immunoinflammatory parameters were found between both groups. The NEWS-2 score was reduced, in 23 IN-DXM treated patients, with no significant variations in the 46 IV-DXM treated ones. Ten IV-DXM-treated patients and only one IN-DXM patient died.

CONCLUSIONS

IN-DMX reduced NEWS-2 and mortality more efficiently than IV-DXM, suggesting that IN is a more efficient route of DXM administration.

Peripheral inflammation is a potential etiological factor in Alzheimer's disease

Peripheral inflammation could constitute a risk factor for AD. This review summarizes the research related to peripheral inflammation that appears to have a relationship with Alzheimer's disease. We find there are significant associations between AD and peripheral infection induced by various pathogens, including herpes simplex virus type 1, cytomegalovirus, Epstein-Barr virus, human immunodeficiency virus, severe acute respiratory syndrome coronavirus 2, Porphyromonas gingivalis, Helicobacter pylori, and Toxoplasma gondii. Chronic inflammatory diseases are also reported to contribute to the pathophysiology of AD. The mechanisms by which peripheral inflammation affects the pathophysiology of AD are complex. Pathogen-derived neurotoxic molecule composition, disrupted BBB, and dysfunctional neurogenesis may all play a role in peripheral inflammation, promoting the development of AD. Anti-pathogenic medications and anti-inflammatory treatments are reported to decrease the risk of AD. Studies that could improve understanding the associations between AD and peripheral inflammation are needed. If our assumption is correct, early intervention against inflammation may be a potential method of preventing and treating AD.

Deciphering the prognostic significance of anoikis-related lncRNAs in invasive breast cancer: from comprehensive bioinformatics analysis to functional experimental validation

The global prevalence of breast cancer necessitates the development of innovative prognostic markers and therapeutic strategies. This study investigated the prognostic implications of anoikis-related long non-coding RNAs (ARLs) in invasive breast cancer (IBC), which is an area that has not been extensively explored. By integrating the RNA sequence transcriptome and clinical data from The Cancer Genome Atlas (TCGA) database and employing advanced regression analyses, we devised a novel prognostic model based on ARL scores. ARL scores correlated with diverse clinicopathological parameters, cellular pathways, distinct mutation patterns, and immune responses, thereby affecting both immune cell infiltration and anticipated responses to chemotherapy and immunotherapy. Additionally, the overexpression of a specific lncRNA, AL133467.1, significantly impeded the proliferation and migration, as well as possibly the anoikis resistance of breast cancer cells. These findings highlight the potential of the ARL signature as a robust prognostic tool and a promising basis for personalized IBC treatment strategies.

Molecular docking, synthesis, characteristics and preliminary cytotoxic study of new coumarin-sulfonamide derivatives as histone deacetylase inhibitors

OBJECTIVE

Aim: To evaluate the cytotoxic activity of newly synthesized a series of novel HDAC inhibitors comprising sulfonamide as zinc binding group and Coumarin as cap groups.

PATIENTS AND METHODS

Materials and Methods: The utilization of sulfonamide as zinc binding group and Coumarin as cap groups known to possess antitumor activity in the designed of new histone deacetylase inhibitors and using the docking and MTT assay to evaluate the compounds.

RESULTS

Results: Four compounds have been synthesized and characterized successfully by ART-FTIR, NMR and ESI-Ms. The synthesized compound assessed for their cytotoxic activity against hepatoblastoma HepG2 (IC50, I=0.094, II=0.040, III=0.032, IV=0.046, SAHA=0.141) and human colon adenocarcinoma MCF-7 (IC50, I=0.135, II=0.050, III= 0.065, IV=0.059, SAHA=0.107). The binding mode to the active site of [HDAC6] were determined by docking study which give results that they might be good inhibitors for [HDAC6].

CONCLUSION

Conclusions: The synthesized compounds (I, II, III and IV) showed a comparable cytotoxic result with FDA approved drug (SAHA) toward HepG2 and MCF-7 cancer cell lines and their docking analysis provided a preliminary indication that they are viable [HDAC6] candidates.

LncRNA xist regulates sepsis associated neuroinflammation in the periventricular white matter of CLP rats by miR-122-5p/PKCη Axis

Background

Neuroinflammation is a common feature of many neurological diseases, and remains crucial for disease progression and prognosis. Activation of microglia and astrocytes can lead to neuroinflammation. However, little is known about the role of lncRNA xist and miR-122-5p in the pathogenesis of sepsis-associated neuroinflammation (SAN). This study aims to investigate the role of lncRNA xist and miR-122-5p in the pathogenesis of SAN.

Methods

Levels of miR-122-5p and proinflammatory mediators were detected in the cerebrospinal fluid (CSF) of patients with intracranial infection (ICI) by ELISA and qRT-PCR. miRNA expression in the periventricular white matter (PWM) in rats was analyzed by high-throughput sequencing. Levels of lncRNA xist, miR-122-5p and proinflammatory mediators in the PWM were measured using qRT-PCR and western blot. Bioinformatics analysis was used to predict the upstream and downstream of miR-122-5p. The interaction between miR-122-5p and its target protein was validated using luciferase reporter assay. BV2 and astrocytes were used to detect the expression of lncRNA xist, miR-122-5p.

Results

The level of miR-122-5p was significantly decreased in the CSF of ICI patients, while the expression of IL-1β and TNF-α were significantly upregulated. Furthermore, it was found that the expression of IL-1β and TNF-α were negatively correlated with the level of miR-122-5p. A high-throughput sequencing analysis showed that miR-122-5p expression was downregulated with 1.5-fold changes in the PWM of CLP rats compared with sham group. Bioinformatics analysis found that lncRNA xist and PKCη were the upstream and downstream target genes of miR-122-5p, respectively. The identified lncRNA xist and PKCη were significantly increased in the PWM of CLP rats. Overexpression of miR-122-5p or knockdown of lncRNA xist could significantly downregulate the level of PKCη and proinflammatory mediators from activated microglia and astrocytes. Meanwhile, in vitro investigation showed that silencing lncRNA xist or PKCη or enhancing the expression of miR-122-5p could obviously inhibit the release of proinflammatory mediators in activated BV2 cells and astrocytes.

Conclusion

LncRNA xist could regulate microglia and astrocytes activation in the PWM of CLP rats via miR-122-5p/PKCη axis, further mediating sepsis associated neuroinflammation.

J147 ameliorates sepsis-induced depressive-like behaviors in mice by attenuating neuroinflammation through regulating the TLR4/NF-κB signaling pathway

Neuroinflammation is associated with the pathophysiology of depression. The molecular mechanism of depressive-like behavior caused by sepsis-associated encephalopathy (SAE) is incompletely understood. J147 (an analog of curcumin) has been reported to improve memory and has neuroprotective activity, but its biological function in the depressive-like behavior observed in SAE is not known. We investigated the effects of J147 on lipopolysaccharide (LPS)-induced neuroinflammatory, depressive-like behaviors, and the toll-like receptor 4 (TLR4)/nuclear factor-κB (NF-κB) signal pathway in the mouse hippocampus and microglia (BV2 cells). The forced-swimming test (FST) and tail-suspension test (TST) were undertaken for assessment of depressive-like behaviors. Expression of the proinflammatory genes interleukin (IL)-6, IL-1β, and tumor necrosis factor (TNF)-α were measured using RT-qPCR and ELISA. Microglia activation was detected using immunofluorescence staining. The TLR4/NF-κB signaling pathway was studied using western blotting and immunofluorescence staining. J147 pretreatment markedly downregulated expression of IL-6, IL-1β, and TNF-α, and the mean fluorescence intensity of ionized calcium-binding adapter protein-1 in microglia. J147 restrained LPS-induced nuclear translocation of nuclear factor-kappa B (NF-κB), inhibitor of nuclear factor kappa B (IκB) degradation, and TLR4 activation in microglia. J147 administration inhibited bodyweight loss, mortality, microglia activation, and depressive-like behaviors in LPS-treated mice. In conclusion, J147 ameliorated the sepsis-induced depressive-like behaviors induced by neuroinflammation through attenuating the TLR4/NF-κB signaling pathway in microglia.

ß1-adrenergic blockers preserve neuromuscular function by inhibiting the production of extracellular traps during systemic inflammation in mice

Severe inflammation via innate immune system activation causes organ dysfunction. Among these, the central nervous system (CNS) is particularly affected by encephalopathies. These symptoms are associated with the activation of microglia and a potential infiltration of leukocytes. These immune cells have recently been discovered to have the ability to produce extracellular traps (ETs). While these components capture and destroy pathogens, deleterious effects occur such as reduced neuronal excitability correlated with excessive ETs production. In this study, the objectives were to determine (1) whether immune cells form ETs in the CNS during acute inflammation (2) whether ETs produce neuromuscular disorders and (3) whether an immunomodulatory treatment such as β1-adrenergic blockers limits these effects. We observed an infiltration of neutrophils in the CNS, an activation of microglia and a production of ETs following lipopolysaccharide (LPS) administration. Atenolol, a β1-adrenergic blocker, significantly decreased the production of ETs in both microglia and neutrophils. This treatment also preserved the gastrocnemius motoneuron excitability. Similar results were observed when the production of ETs was prevented by sivelestat, an inhibitor of ET formation. In conclusion, our results demonstrate that LPS administration increases neutrophils infiltration into the CNS, activates immune cells and produces ETs that directly impair neuromuscular function. Prevention of ETs formation by β1-adrenergic blockers partly restores this function and could be a good target in order to reduce adverse effects in severe inflammation such as sepsis but also in other motor related pathologies linked to ETs production.

MiR-155 promotes inflammation and apoptosis via targeting SIRT1 in hypoxic-ischemic brain damage

Hypoxic-ischemic brain damage (HIBD) is one of the major causes of infant death and long-term neurological disturbances, which puts great pressure on families and society. Previous studies have reported that neuroinflammation regulates the pathogenesis of HIBD. MiR-155 has been reported to participate in many brain injuries; however, its direct implication and related mechanisms are not illuminated in HIBD. Herein, we identified that miR-155 plays a vital role in HIBD both in in vitro and in vivo models. We found that miR-155 promoted inflammation and apoptosis via targeting SIRT1 and negatively regulated its expression levels in oxygen-glucose deprivation/reoxygenation (OGD/R) in an in vitro model. Silencing of SIRT1 reversed the effects of miR-155 inhibitor on apoptosis and the NF-κB pathway in OGD/R-treated PC12 cells and microglia (BV2) cells. Moreover, in a neonatal rat HIBD model, miR-155 enhanced apoptosis and inflammation in the brains of rats with HIBD in vivo. Together, our results demonstrated that miR-155 exerted a negative effect in HIBD by targeting SIRT1, which could contribute to the treatment of neonatal patients with hypoxic-ischemic brain damage.

Hemp Protein Hydrolysates Modulate Inflammasome-Related Genes in Microglial Cells

A prolonged inflammatory response can lead to the development of neurodegenerative diseases such as Alzheimer's disease. Enzymatic hydrolysis is a sustainable way to increase the value of protein sources by obtaining peptides that can exert bioactivity. Hemp (Cannabis sativa L.) protein hydrolysates have been proven to exert anti-inflammatory activity. In this study, two hemp protein hydrolysate (HPHs), obtained with Alcalase as sole catalyst, or with Alcalase followed by Flavourzyme, were evaluated as inflammatory mediators (TNFα, IL-1β, IL-6, and IL-10), microglial polarization markers (Ccr7, iNos, Arg1, and Ym1), and genes related to inflammasome activation (Nlrp3, Asc, Casp1, and Il18), employing the lipopolysaccharide (LPS)-induced neuroinflammation model in murine BV-2 microglial cells. A significant decrease of the expression of proinflammatory genes (e.g., Tnfα, Ccr7, inos, and Nlrp3, among others) and increase of the expression anti-inflammatory cytokines in microglial cells was observed after treatment with the test HPHs. This result in the cell model suggests a polarization toward an anti-inflammatory M2 phenotype. Our results show that the evaluated HPHs show potential neuroprotective activity in microglial cells via the inflammasome.

A dual tracer [11C]PBR28 and [18F]FDG microPET evaluation of neuroinflammation and brain energy metabolism in murine endotoxemia

BACKGROUND

Brain metabolic alterations and neuroinflammation have been reported in several peripheral inflammatory conditions and present significant potential for targeting with new diagnostic approaches and treatments. However, non-invasive evaluation of these alterations remains a challenge.

METHODS

Here, we studied the utility of a micro positron emission tomography (microPET) dual tracer ([11C]PBR28 - for microglial activation and [18F]FDG for energy metabolism) approach to assess brain dysfunction, including neuroinflammation in murine endotoxemia. MicroPET imaging data were subjected to advanced conjunction and individual analyses, followed by post-hoc analysis.

RESULTS

There were significant increases in [11C]PBR28 and [18F]FDG uptake in the hippocampus of C57BL/6 J mice 6 h following LPS (2 mg/kg) intraperitoneal (i.p.) administration compared with saline administration. These results confirmed previous postmortem observations. In addition, patterns of significant simultaneous activation were demonstrated in the hippocampus, the thalamus, and the hypothalamus in parallel with other tracer-specific and region-specific alterations. These changes were observed in the presence of robust systemic inflammatory responses manifested by significantly increased serum cytokine levels.

CONCLUSIONS

Together, these findings demonstrate the applicability of [11C]PBR28 - [18F]FDG dual tracer microPET imaging for assessing neuroinflammation and brain metabolic alterations in conditions "classically" characterized by peripheral inflammatory and metabolic pathogenesis.

Brief Psychotic Episode After Vitamin C Overdose Due to Fear of Getting COVID-19

Coronavirus infection (COVID-19) caused by the new coronavirus SARSCoV-2 is a global public health problem. Ascorbic acid (vitamin C) is low-cost, safe, antioxidant, anti-inflammatory, and immunomodulating, and has viral load-reducing effects when taken as a supplement. In addition, vitamin C neutralizes free radicals and protects the body against cellular damage, and it can provide a protective effect against cardiovascular diseases by regulating the production of free radicals via nitric oxide. This situation makes ascorbic acid a notable treatment candidate for preventing the worsening of COVID-19. In our case, we present a patient who had a brief psychotic episode following ingestion of high-dose vitamin C due to fear of getting infected with SARS-CoV-2. The psychotic episode may have developed due to increased levels of circulating vitamin C in the central nervous system, which may affect dopamine and GABA levels and changes in NMDA receptor function in the brain. We aim to draw attention to possible neurotoxicity and inflammation caused by free radicals on neuropsychiatric diseases. [ Psychiatr Ann . 2022;52(10):442–444.]

LPS-Induced Coagulation and Neuronal Damage in a Mice Model Is Attenuated by Enoxaparin

Background. Due to the interactions between neuroinflammation and coagulation, the neural effects of lipopolysaccharide (LPS)-induced inflammation (1 mg/kg, intraperitoneal (IP), n = 20) and treatment with the anti-thrombotic enoxaparin (1 mg/kg, IP, 15 min, and 12 h following LPS, n = 20) were studied in C57BL/6J mice. Methods. One week after LPS injection, sensory, motor, and cognitive functions were assessed by a hot plate, rotarod, open field test (OFT), and Y-maze. Thrombin activity was measured with a fluorometric assay; hippocampal mRNA expression of coagulation and inflammation factors were measured by real-time-PCR; and serum neurofilament-light-chain (NfL), and tumor necrosis factor-α (TNF-α) were measured by a single-molecule array (Simoa) assay. Results. Reduced crossing center frequency was observed in both LPS groups in the OFT (p = 0.02), along with a minor motor deficit between controls and LPS indicated by the rotarod (p = 0.057). Increased hippocampal thrombin activity (p = 0.038) and protease-activated receptor 1 (PAR1) mRNA (p = 0.01) were measured in LPS compared to controls, but not in enoxaparin LPS-treated mice (p = 0.4, p = 0.9, respectively). Serum NfL and TNF-α levels were elevated in LPS mice (p < 0.05) and normalized by enoxaparin treatment. Conclusions. These results indicate that inflammation, coagulation, neuronal damage, and behavior are linked and may regulate each other, suggesting another pharmacological mechanism for intervention in neuroinflammation.

Role of Caveolin-1 in Sepsis – A Mini-Review

Sepsis is a generalized disease characterized by an extreme response to a severe infection. Moreover, challenges remain in the diagnosis, treatment and management of septic patients. In this mini-review we demonstrate developments on cellular pathogenesis and the role of Caveolin-1 (Cav-1) in sepsis. Studies have shown that Cav-1 has a significant role in sepsis through the regulation of membrane traffic and intracellular signaling pathways. In addition, activation of apoptosis/autophagy is considered relevant for the progression and development of sepsis. However, how Cav-1 is involved in sepsis remains unclear, and the precise mechanisms need to be further investigated. Finally, the role of Cav-1 in altering cell permeability during inflammation, in sepsis caused by microorganisms, apoptosis/autophagy activation and new therapies under study are discussed in this mini-review.

Intranasal Methylprednisolone Ameliorates Neuroinflammation Induced by Chronic Toluene Exposure

Inhalants are chemical substances that induce intoxication, and toluene is the main component of them. Increasing evidence indicates that a dependence on inhalants involves a state of chronic stress associated to the activation of immune cells in the central nervous system and release of proinflammatory mediators, especially in some brain areas such as the nucleus accumbens and frontal cortex, where the circuits of pleasure and reward are. In this study, anti-neuroinflammatory treatment based on a single dose of intranasal methylprednisolone was assessed in a murine model of chronic toluene exposure. The levels of proinflammatory mediators, expression levels of Iba-1 and GFAP, and histological changes in the frontal cortex and nucleus accumbens were evaluated after the treatment. The chronic exposure to toluene significantly increased the levels of TNF-α, IL-6, and NO, the expression of GFAP, and induced histological alterations in mouse brains. The treatment with intranasally administered MP significantly reduced the expression of TNF-α and NO and the expression of GFAP (p < 0.05); additionally, it reversed the central histological damage. These results indicate that intranasally administered methylprednisolone could be considered as a treatment to reverse neuroinflammation and histological damages associated with the use of inhalants.

Polarization of Microglia and Its Therapeutic Potential in Sepsis

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

Emodin relieves the inflammation and pyroptosis of lipopolysaccharide-treated 1321N1 cells by regulating methyltransferase-like 3 -mediated NLR family pyrin domain containing 3 expression

Sepsis brain injury (SBI) is a major cause of death in critically ill patients. The present study aimed to investigate the role of emodin in SBI development. Human astrocyte 1321N1 cells were stimulated with 100 ng/mL lipopolysaccharide (LPS) to establish an SBI model in vitro. Flow cytometry was performed to measure the cell pyroptosis. The protein expression levels of syndecan-1 (SDC-1), NLR family pyrin domain containing 3 (NLRP3), Caspase-1, and the N-terminal fragment of gasdermin D (GSDMD-N) were measured using Western blotting. Interleukin (IL)-1β, IL-6, IL-10, and tumor necrosis factor (TNF)-α levels in cells were measured using enzyme-linked immunosorbent assay kits. The N⁶-methyladenosine (m⁶A) modification was analyzed using the methylated RNA immunoprecipitation assay. NLRP3 activator, nigericin, was used to overexpress NLRP3. LPS treatment significantly enhanced the pyroptosis in 1321N1 cells, increased the levels of TNF-α, IL-1β, and IL-6, and decreased the levels of IL-10. The protein expression levels of NLRP3, SDC-1, GSDMD-N, and Caspase-1 were also increased. Emodin treatment decreased the levels of TNF-α, IL-1β, IL-6, NLRP3, SDC-1, GSDMD-N, and Caspase-1, while increasing the levels of IL-10 in LPS-treated 1321N1 cells. Nigericin reversed the effects of emodin. Furthermore, emodin upregulated m⁶A levels in NLRP3 by increasing the expression of methyltransferase-like 3 (METTL3). Meanwhile, knockdown of METTL3 reversed the effects of emodin on the mRNA expression and stability of NLRP3. Therefore, emodin inhibits the inflammation and pyroptosis of LPS-treated 1321N1 cells by inactivating METTL3-mediated NLRP3 expression.

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.

Electroacupuncture ameliorates neuroinflammation in animal models

Background:

Neuroinflammation refers to a wide range of immune responses occurring in the brain or spinal cord. It is closely related to a variety of neurodegenerative diseases, for which it potentially represents a new direction for treatment. Electroacupuncture (EA) is one method of acupuncture treatment, which can be used as an adjuvant therapy for many diseases. This review focuses on molecular mechanisms of EA in the reduction of neuroinflammation, summarizes relevant basic research and outlines future directions for investigation.

Findings:

A growing body of basic research has shown that EA can ameliorate neuroinflammation centrally (in animal models of ischemic stroke, Alzheimer’s disease, traumatic brain injury, spinal cord injury, Parkinson’s disease and vascular dementia) and peripherally (e.g. after a surgical insult or injection of lipopolysaccharide) and that its effects involve different molecular mechanisms, including activation of the α7 nicotinic acetylcholine receptor signaling pathway and P2 type purinergic receptors, inhibition of nuclear factor κB, and mitigation of damage secondary to oxidative stress and NOD-like receptor protein 3 inflammasome activation.

Conclusions:

EA is capable of regulating multiple cell signal transduction pathways to alleviate neuroinflammation in animal models. Although the findings of animal studies are encouraging, further prospective clinical trials are needed to verify the efficacy of EA for the treatment of neuroinflammation.

Intranasal dexamethasone: a new clinical trial for the control of inflammation and neuroinflammation in COVID-19 patients

Background

By end December of 2021, COVID-19 has infected around 276 million individuals and caused over 5 million deaths worldwide. Infection results in dysregulated systemic inflammation, multi-organ dysfunction, and critical illness. Cells of the central nervous system are also affected, triggering an uncontrolled neuroinflammatory response. Low doses of glucocorticoids, administered orally or intravenously, reduce mortality among moderate and severe COVID-19 patients. However, low doses administered by these routes do not reach therapeutic levels in the CNS. In contrast, intranasally administered dexamethasone can result in therapeutic doses in the CNS even at low doses.

Methods

This is an approved open-label, multicenter, randomized controlled trial to compare the effectiveness of intranasal versus intravenous dexamethasone administered in low doses to moderate and severe COVID-19 adult patients. The protocol is conducted in five health institutions in Mexico City. A total of 120 patients will be randomized into two groups (intravenous vs. intranasal) at a 1:1 ratio. Both groups will be treated with the corresponding dexamethasone scheme for 10 days. The primary outcome of the study will be clinical improvement, defined as a statistically significant reduction in the NEWS-2 score of patients with intranasal versus intravenous dexamethasone administration. The secondary outcome will be the reduction in mortality during hospitalization.

Conclusions

This protocol is currently in progress to improve the efficacy of the standard therapeutic dexamethasone regimen for moderate and severe COVID-19 patients.

Trial registration

ClinicalTrials.govNCT04513184. Registered November 12, 2020. Approved by La Comisión Federal para la Protección contra Riesgos Sanitarios (COFEPRIS) with identification number DI/20/407/04/36. People are currently being recruited.

Graphical abstract

REVIVAL is a multicenter, open-label, randomized, controlled study to compare the standard low doses of intravenous dexamethasone with weight-adjusted low doses of intranasal dexamethasone.

Intranasal dexamethasone can reach the respiratory tract more effectively than intravenous administration.

Intranasal dexamethasone can reach the central nervous system in therapeutic concentrations, even at low doses.

REVIVAL aims to reduce central failures and sequelae by controlling not only systemic inflammation but also neuroinflammation.

Sepsis-Exacerbated Brain Dysfunction After Intracerebral Hemorrhage

Sepsis susceptibility is significantly increased in patients with intracerebral hemorrhage (ICH), owing to immunosuppression and intestinal microbiota dysbiosis. To date, ICH with sepsis occurrence is still difficult for clinicians to deal with, and the mortality, as well as long-term cognitive disability, is still increasing. Actually, intracerebral hemorrhage and sepsis are mutually exacerbated via similar pathophysiological mechanisms, mainly consisting of systemic inflammation and circulatory dysfunction. The main consequence of these two processes is neural dysfunction and multiple organ damages, notably, via oxidative stress and neurotoxic mediation under the mediation of central nervous system activation and blood-brain barrier disruption. Besides, the comorbidity-induced multiple organ damages will produce numerous damage-associated molecular patterns and consequently exacerbate the severity of the disease. At present, the prospective views are about operating artificial restriction for the peripheral immune system and achieving cross-tolerance among organs via altering immune cell composition to reduce inflammatory damage.

Inhibition or Deletion of Hydroxylases-Prolyl-4-Hydroxyases 3 Alleviates Lipopolysaccharide-induced Neuroinflammation and Neurobehavioral Deficiency

It is well known that neuroinflammation plays a key role in neurodegenerative diseases. Hypoxia-inducible factor (HIF) and its hydroxylases-Prolyl-4-hydroxyases (PHDs) have been found to modulate the inflammatory processes. Here, the effects of PHDs enzyme onlipopolysaccharide-induced neuroinflammation and neurocognitive deficits were investigated. BV2 microglia cells were stimulated by LPS (1 μg/ml) as neuroinflammation model in vitro. Dimethyloxalylglycine (DMOG, 100 μM) and PHD3-siRNA were used to suppress the expression of PHD3. In vivo, mice received consecutive intraperitoneal injection of LPS (500 μg/kg) for 7 days, and intraperitoneal injection of DMOG (100 mg/kg) was applied 1 h before LPS at the same days. Several neurobehavioral tests (Open field, Novel object recognition and Morris water maze) were used to measure cognitive function. RT-qPCR and Western blotting were used to investigate the expression of inflammatory cytokines, HIF-PHDs protein. Metabolic reprogramming was measured by seahorse method. The results revealed that LPS induced neuroinflammation and PHD3 expression in vivo and vitro. DMOG and PHD3knockout decreased expression of inflammatory cytokines and improved the metabolic reprogramming caused by LPS treatment. Furthermore, pretreatment of DMOG reversed learning and memory deficits in systemic LPS-exposed mice through anti-neuroinflammation, which is independent of DMOG angiogenesis. These findings suggested that PHD3 may mediate LPS-induced microglial activation and neuroinflammation-associated neurobehavioral deficits.

Agomelatine protects heart and aorta against lipopolysaccharide-induced cardiovascular toxicity via inhibition of NF-kβ phosphorylation

The aim of this study was to investigate the possible ameliorating effects of agomelatine (AGO) on lipopolysaccharide (LPS)-induced endothelial and cardiac damage. Twenty-four female Wistar Albino rats divided into 3 groups as follows: Control, LPS and LPS + AGO. Total oxidant status (TOS), total antioxidant status (TAS), nuclear factor kappa beta (NF-kβ)/p65, p-NF-kβ, full caspase-8 (Cas-8) and cleaved cas-8 levels were measured in cardiac tissues and creatine kinase MB (CKMB), aspartate aminotransferase (AST), lactate dehydrogenase (LDH) levels in blood biochemically. In addition; cas-8, sirtuin-1 (SIRT-1), interleukin-4 (IL-4), interleukin-10 (IL-10), haptoglobin measured histopathologically in cardiac and aortic tissues. The levels of CKMB, AST, LDH and TOS were increased and TAS were decreased in the LPS group. In Western blot analyses NF-kβ/p65, p-NF-kβ/p65, full and cleaved cas-8 protein levels increased in cardiac tissues of LPS group. In histopathological and immunohistochemical evaluation of the heart sections; hyperemia, micro-hemorrhages and inflammatory cell infiltrations, increase of cas-8, haptoglobin, IL-4 and IL-10 and decrease of SIRT-1 levels were observed in cardiac and endothelial tissues of LPS groups. AGO treatment reversed all these parameters. It was shown that LPS-induced inflammation, oxidative stress and apoptosis via increasing of NF-kβ/p65 signaling, decreasing of SIRT-1 levels and increase of cas-8 levels in heart and endothelial tissues respectively. AGO corrected all these parameters by its antioxidant, antiinflammatory and antiapoptotic activities.

Circadian Rhythms in Bacterial Sepsis Pathology: What We Know and What We Should Know

Sepsis is a syndrome caused by a deregulated host response to infection, representing the primary cause of death from infection. In animal models, the mortality rate is strongly dependent on the time of sepsis induction, suggesting a main role of the circadian system. In patients undergoing sepsis, deregulated circadian rhythms have also been reported. Here we review data related to the timing of sepsis induction to further understand the different outcomes observed both in patients and in animal models. The magnitude of immune activation as well as the hypothermic response correlated with the time of the worst prognosis. The different outcomes seem to be dependent on the expression of the clock gene Bmal1 in the liver and in myeloid immune cells. The understanding of the role of the circadian system in sepsis pathology could be an important tool to improve patient therapies.

Matairesinol exerts anti-inflammatory and antioxidant effects in sepsis-mediated brain injury by repressing the MAPK and NF-κB pathways through up-regulating AMPK

Brain injury is a familiar complication of severe sepsis, in which excessive inflammation and oxidative stress are the main mechanisms leading to acute brain injury. Here, we focus on probing the function and mechanism of Matairesinol (Mat) in sepsis-mediated brain injury. We established a rat sepsis model by cecal ligation and perforation (CLP) and constructed an in vitro sepsis model by treating neurons and microglia with lipopolysaccharide (LPS). Rats and cells were treated with varying concentrations of Mat, and the changes of neural function, neuronal apoptosis, microglial activation, neuroinflammation and the expression of oxidative stress factors in brain tissues were examined. Additionally, the activation of the MAPK, NF-κB and AMPK pathways in brain tissues and cells was evaluated by Western blot (WB) and/or immunohistochemistry (IHC). Our findings illustrated that Mat improved neuronal apoptosis and weakened microglial activation in CLP rats. Meanwhile, Mat hampered the expression of pro-inflammatory factors (TNF-α, IL-1β, IL-6, IFN-γ, IL-8, and MCP1) and facilitated the contents of glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) in brain tissues and microglia. Mechanistically, Mat concentration-dependently dampened the phosphorylation of MAPK, JNK and NF-κB in CLP rats and LPS-stimulated microglia and up-regulated Nrf2 and HO-1. Besides, Mat facilitated the AMPK expression. Meanwhile, Compound C, a specific inhibitor of the AMPK pathway, substantially reduced the neuronal protection and anti-inflammatory effects mediated by Mat. Overall, Mat exerts anti-inflammatory and anti-oxidative stress effects by up-regulating AMPK, thereby ameliorating sepsis-mediated brain injury.

Matairesinol exerts anti-inflammatory and antioxidant effects in sepsis-mediated brain injury by repressing the MAPK and NF-κB pathways through up-regulating AMPK

Brain injury is a familiar complication of severe sepsis, in which excessive inflammation and oxidative stress are the main mechanisms leading to acute brain injury. Here, we focus on probing the function and mechanism of Matairesinol (Mat) in sepsis-mediated brain injury. We established a rat sepsis model by cecal ligation and perforation (CLP) and constructed an in vitro sepsis model by treating neurons and microglia with lipopolysaccharide (LPS). Rats and cells were treated with varying concentrations of Mat, and the changes of neural function, neuronal apoptosis, microglial activation, neuroinflammation and the expression of oxidative stress factors in brain tissues were examined. Additionally, the activation of the MAPK, NF-κB and AMPK pathways in brain tissues and cells was evaluated by Western blot (WB) and/or immunohistochemistry (IHC). Our findings illustrated that Mat improved neuronal apoptosis and weakened microglial activation in CLP rats. Meanwhile, Mat hampered the expression of pro-inflammatory factors (TNF-α, IL-1β, IL-6, IFN-γ, IL-8, and MCP1) and facilitated the contents of glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) in brain tissues and microglia. Mechanistically, Mat concentration-dependently dampened the phosphorylation of MAPK, JNK and NF-κB in CLP rats and LPS-stimulated microglia and up-regulated Nrf2 and HO-1. Besides, Mat facilitated the AMPK expression. Meanwhile, Compound C, a specific inhibitor of the AMPK pathway, substantially reduced the neuronal protection and anti-inflammatory effects mediated by Mat. Overall, Mat exerts anti-inflammatory and anti-oxidative stress effects by up-regulating AMPK, thereby ameliorating sepsis-mediated brain injury.

Nose-to-Brain Delivery of Dexamethasone: Biodistribution Studies in Mice

Neuroinflammation (NI) is an important physiologic process which promotes the tissue repair and homeostatic maintenance in the central nervous system after different types of insults. However, when it is exacerbated and sustained in time, NI plays a critical role in the pathogenesis of different neurologic diseases. The high systemic doses required for brain-specific targeting lead to severe undesirable effects. The intranasal (IN) route has been proposed as an alternative drug administration route for a better NI control. Herein, the brain biodistribution of intranasally administered dexamethasone versus intravenously administered one is reported. A higher amount of dexamethasone was found in every analyzed region of those brains of intranasally administered mice. HPLC analysis also revealed that IN administration allows Dex to arrive faster and in a greater concentration to the brain in comparison with intravenous administration, data confirmed by immunofluorescence and HPLC analysis. These data support the proposal of the IN administration of Dex as an alternative for a more efficient control of NI. SIGNIFICANCE STATEMENT: This work highlights the biodistribution of dexamethasone after its intranasal administration. Intranasal administration allows for a faster arrival, better distribution, and a higher concentration of the drug within the brain compared to its intravenous administration. These results explain some of the evidence shown in a previous work in which dexamethasone controls neuroinflammation in a murine stroke model and can be used to propose alternative treatments for neuroinflammatory diseases.

MicroRNA-139-5p improves sepsis-induced lung injury by targeting Rho-kinase1

Sepsis-induced acute lung injury (ALI) is an inflammatory process that involves inflammatory cytokine production and cell apoptosis. In the present study, the regulatory role of microRNA (miR)-139-5p in sepsis-induced ALI was investigated using a murine model of cecal ligation puncture (CLP) and an in vitro model using lipopolysaccharide (LPS)-induced normal human bronchial epithelial cells (NHBEs). Sepsis-induced pathological changes in the lungs of ALI mice were detected using hematoxylin and eosin staining. Lung water content was determined, and the expression of proinflammatory cytokines in the bronchoalveolar lavage fluid and serum of sepsis-induced ALI mice were quantified using ELISA. The levels of oxidative stress in lung tissues were determined using commercial kits. The degree of apoptosis was determined using a TUNEL assay. The expression levels of miR-139-5p and Rho-kinase 1 (ROCK1) were determined using reverse transcription-quantitative PCR and western blot analyses. A dual-luciferase reporter assay was used to confirm the direct targeting of ROCK1 by miR-139-5p. NHBEs were co-transfected with vectors expressing ROCK1 (or empty vector) and miR-139-5p mimics or control mimics prior to LPS treatment. The transcriptional activity of caspase-3, the ratio of apoptotic cells, the expression levels of mucin 5AC, mucin 1, TNF-α, IL-1β, IL-6, NLR family pyrin domain containing 3, apoptosis-associated speck-like protein containing a CARD and caspase-1 were evaluated. Compared with the normal group, mice that underwent CLP exhibited abnormal lung morphology, enhanced production of TNF-α, IL-1β and IL-6, increased reactive oxygen species (ROS), malondialdehyde and lactate dehydrogenase levels, an increased proportion of apoptotic cells and increased ROCK1 expression. Superoxide dismutase, glutathione peroxidase and miR-139-5p levels were decreased following CLP. In the NHBEs, stimulation with LPS caused a marked increase in inflammatory cytokine levels and apoptosis compared with the untreated cells. Overexpression of miR-139-5p attenuated cell apoptosis and inflammation. Overexpression of ROCK1 in NHBEs restored the ROS levels and proinflammatory cytokine production inhibited by miR-139-5p. In conclusion, miR-139-5p alleviated sepsis-induced ALI via suppression of its downstream target, ROCK1, suggesting that miR-139-5p may hold promise in the treatment of sepsis-induced ALI.

Dementia and COVID-19, a Bidirectional Liaison: Risk Factors, Biomarkers, and Optimal Health Care

Cognitive impairment following SARS-CoV-2 infection is being increasingly recognized as an acute and possibly also long-term sequela of the disease. Direct viral entry as well as systemic mechanisms such as cytokine storm are thought to contribute to neuroinflammation in these patients. Biomarkers of COVID-19-induced cognitive impairment are currently lacking, but there is some limited evidence that SARS-CoV-2 could preferentially target the frontal lobes, as suggested by behavioral and dysexecutive symptoms, fronto-temporal hypoperfusion on MRI, EEG slowing in frontal regions, and frontal hypometabolism on 18F-FDG-PET. Possible confounders include cognitive impairment due to hypoxia and mechanical ventilation and post-traumatic stress disorder. Conversely, patients already suffering from dementia, as well as their caregivers, have been greatly impacted by the disruption of their care caused by COVID-19. Patients with dementia have experienced worsening of cognitive, behavioral, and psychological symptoms, and the rate of COVID-19-related deaths is disproportionately high among cognitively impaired people. Multiple factors, such as difficulties in remembering and executing safeguarding procedures, age, comorbidities, residing in care homes, and poorer access to hospital standard of care play a role in the increased morbidity and mortality. Non-pharmacological interventions and new technologies have shown a potential for the management of patients with dementia, and for the support of their caregivers.

New clinical and pathophysiological perspectives defining the trajectory of cirrhosis

Traditionally, the complications of cirrhosis, namely variceal bleeding, ascites and hepatic encephalopathy, were thought to result predominantly from circulatory dysfunction and altered organ perfusion arising as a result of portal hypertension. Over the past 20 years, large, international prospective studies have indicated the importance of systemic inflammation and organ immunopathology as additional determinants of organ dysfunction in cirrhosis, which not only manifests in the liver, brain, circulation and the kidneys, but also the immune system, gut, muscles, adrenal glands, reproductive organs, heart and lungs. This review provides an overview of the traditional and emerging concepts around the initiation and maintenance of organ dysfunction in cirrhosis and proposes a new paradigm based upon a better understanding of acute decompensation of cirrhosis. The interaction between the traditional concepts and the emerging perspectives remains a matter of great interest and the basis for future research.

Neuronal Damage and Neuroinflammation, a Bridge Between Bacterial Meningitis and Neurodegenerative Diseases

Bacterial meningitis is an inflammation of the meninges which covers and protects the brain and the spinal cord. Such inflammation is mostly caused by blood-borne bacteria that cross the blood-brain barrier (BBB) and finally invade the brain parenchyma. Pathogens such as Streptococcus pneumoniae, Neisseria meningitidis, and Haemophilus influenzae are the main etiological causes of bacterial meningitis. After trafficking across the BBB, bacterial pathogens in the brain interact with neurons, the fundamental units of Central Nervous System, and other types of glial cells. Although the specific molecular mechanism behind the interaction between such pathogens with neurons is still under investigation, it is clear that bacterial interaction with neurons and neuroinflammatory responses within the brain leads to neuronal cell death. Furthermore, clinical studies have shown indications of meningitis-caused dementia; and a variety of neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease and Huntington's disease are characterized by the loss of neurons, which, unlike many other eukaryotic cells, once dead or damaged, they are seldom replaced. The aim of this review article is to provide an overview of the knowledge on how bacterial pathogens in the brain damage neurons through direct and indirect interactions, and how the neuronal damage caused by bacterial pathogen can, in the long-term, influence the onset of neurodegenerative disorders.

The Therapeutic Effect of Intranasal Administration of Dexamethasone in Neuroinflammation Induced by Experimental Pulmonary Tuberculosis

Tuberculosis (TB) is an important infectious disease and a public health problem. The organs most frequently affected by TB are the lungs; despite this, it has been reported that TB patients suffer from depression and anxiety, which have been attributed to social factors. In previous experimental work, we observed that the extensive pulmonary inflammation characteristic of TB with high cytokine production induces neuroinflammation, neuronal death and behavioral abnormalities in the absence of brain infection. The objective of the present work was to reduce this neuroinflammation and avoid the psycho-affective disorders showed during pulmonary TB. Glucocorticoids (GCs) are the first-line treatment for neuroinflammation; however, their systemic administration generates various side effects, mostly aggravating pulmonary TB due to immunosuppression of cellular immunity. Intranasal administration is a route that allows drugs to be released directly in the brain through the olfactory nerve, reducing their doses and side effects. In the present work, dexamethasone’s (DEX) intranasal administration was evaluated in TB BALB /c mice comparing three different doses (0.05, 0.25 and 2.5 mg/kg BW) on lung disease evolution, neuroinflammation and behavioral alterations. Low doses of dexamethasone significantly decreased neuroinflammation, improving behavioral status without aggravating lung disease.

Adipose-Derived Inflammatory and Coagulant Mediators in Patients With Sepsis

ABSTRACT

Results from preclinical sepsis studies using rodents are often criticized as not being reproducible in humans. Using a murine model, we previously reported that visceral adipose tissues (VAT) are highly active during the acute inflammatory response, serving as a major source of inflammatory and coagulant mediators. The purpose of this study was to determine whether these findings are recapitulated in patients with sepsis and to evaluate their clinical significance. VAT and plasma were obtained from patients undergoing intra-abdominal operations with noninflammatory conditions (control), local inflammation, or sepsis. In mesenteric and epiploic VAT, gene expression of pro-inflammatory (TNFα, IL-6, IL-1α, IL-1β) and pro-coagulant (PAI-1, PAI-2, TSP-1, TF) mediators was increased in sepsis compared with control and local inflammation groups. In the omentum, increased expression was limited to IL-1β, PAI-1, and PAI-2, showing a depot-specific regulation. Histological analyses showed little correlation between cellular infiltration and gene expression, indicating a resident source of these mediators. Notably, a strong correlation between PAI-1 expression in VAT and circulating protein levels was observed, both being positively associated with markers of acute kidney injury (AKI). In another cohort of septic patients stratified by incidence of AKI, circulating PAI-1 levels were higher in those with versus without AKI, thus extending these findings beyond intra-abdominal cases. This study is the first to translate upregulation of VAT mediators in sepsis from mouse to human. Collectively, the data suggest that development of AKI in septic patients is associated with high plasma levels of PAI-1, likely derived from resident cells within VAT.

The systemic inflammation hypothesis: Towards a new paradigm of acute decompensation and multiorgan failure in cirrhosis

Acute decompensation (AD) of cirrhosis is defined by the development of ascites, hepatic encephalopathy and/or variceal bleeding. Ascites is traditionally attributed to splanchnic arterial vasodilation and left ventricular dysfunction, hepatic encephalopathy to hyperammonaemia, and variceal haemorrhage to portal hypertension. Recent large-scale European observational studies have shown that systemic inflammation is a hallmark of AD. Here we present a working hypothesis, the systemic inflammation hypothesis, suggesting that systemic inflammation through an impairment of the functions of one or more of the major organ systems may be a common theme and act synergistically with the traditional mechanisms involved in the development of AD. Systemic inflammation may impair organ system function through mechanisms which are not mutually exclusive. The first mechanism is a nitric oxide-mediated accentuation of the preexisting splanchnic vasodilation, resulting in the overactivation of the endogenous vasoconstrictor systems which elicit intense vasoconstriction and hypoperfusion in certain vascular beds, in particular the renal circulation. Second, systemic inflammation may cause immune-mediated tissue damage, a process called immunopathology. Finally, systemic inflammation may induce important metabolic changes. Indeed, systemic inflammatory responses are energetically expensive processes, requiring reallocation of nutrients (glucose, amino acids and lipids) to fuel immune activation. Systemic inflammation also inhibits nutrient consumption in peripheral (non-immune) organs, an effect that may provide one mechanism of reallocation and prioritisation of metabolic fuels for inflammatory responses. However, the decrease in nutrient consumption in peripheral organs may result in decreased mitochondrial production of ATP (energy) and subsequently impaired organ function.

mTOR inhibition as a possible pharmacological target in the management of systemic inflammatory response and associated neuroinflammation by lipopolysaccharide challenge in rats

Neuroinflammation plays a critical role during sepsis triggered by microglial activation. Mammalian target of rapamycin (mTOR) has gained attraction in neuroinflammation, however, the mechanism remains unclear. Our goal was to assess the effects of mTOR inhibition by rapamycin on inflammation, microglial activation, oxidative stress, and apoptosis associated with the changes in the inhibitor-κB (IκB)-α/nuclear factor-κB (NF-κB)/hypoxia-inducible factor-1α (HIF-1α) pathway activity following a systemic challenge with lipopolysaccharide (LPS). Rats received saline (10 mL/kg), LPS (10 mg/kg), and (or) rapamycin (1 mg/kg) intraperitoneally. Inhibition of mTOR by rapamycin blocked phosphorylated form of ribosomal protein S6, NF-κB p65 activity by increasing degradation of IκB-α in parallel with HIF-1α expression increased by LPS in the kidney, heart, lung, and brain tissues. Rapamycin attenuated the increment in the expression of tumor necrosis factor-α and interleukin-1β, the inducible nitric oxide synthase, gp91^phox, and p47^phox in addition to nitrite levels elicited by LPS in tissues or sera. Concomitantly, rapamycin treatment reduced microglial activation, brain expression of caspase-3, and Bcl-2-associated X protein while it increased expression of B cell lymphoma 2 induced by LPS. Overall, this study supports the hypothesis that mTOR contributes to the detrimental effect of LPS-induced systemic inflammatory response associated with neuroinflammation via IκB-α/NF-κB/HIF-1α signaling pathway.

COVID-19-Associated Acute Brain Dysfunction Related to Sepsis

In global term, as of November 30, 2020, over 30 million people has been infected by a novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and more than 10,000,000 of them died of acute organ failure. Our reviews have shown that coronavirus disease 2019 (COVID-19) patients with pneumonia and acute respiratory distress syndrome (ARDS) have life-threatening acute brain dysfunction (ABD), ranging from altered mental status/delirium to stupor/coma. Altered mental status/delirium was the most common manifestation of ABD caused by severe COVID-19. The prevalence of altered mental status and/or delirium was up to 66-79.5%, and prevalence of coma was 10%. The most common clinical type of COVID-19-associated ABD was COVID-19-associated acute stroke including ischemic and hemorrhagic stroke (n > 350 cases), followed by COVID-19-associated encephalopathy (n > 200 cases), and COVID-19-associated central nervous system (CNS) infection (n > 70 cases). According to the Sepsis-3 criteria, we confess that severe COVID-19-associated ABD with ARDS and altered mental status is related to sepsis. Moreover, we also review the diagnosis and treatment of COVID-19-associated ABD with sepsis. In view of the fact that COVID-19 is at the peak of epidemic worldwide, we hope that this review will provide evidence of COVID-19 sepsis threating to the brain dysunction. Thus, recognizing the COVID-19-associated ABD related to sepsis is very important for early empirical combination therapy to survive severe COVID-19.

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.

Effects of Neurological Disorders on Bone Health

Neurological diseases, particularly in the context of aging, have serious impacts on quality of life and can negatively affect bone health. The brain-bone axis is critically important for skeletal metabolism, sensory innervation, and endocrine cross-talk between these organs. This review discusses current evidence for the cellular and molecular mechanisms by which various neurological disease categories, including autoimmune, developmental, dementia-related, movement, neuromuscular, stroke, trauma, and psychological, impart changes in bone homeostasis and mass, as well as fracture risk. Likewise, how bone may affect neurological function is discussed. Gaining a better understanding of brain-bone interactions, particularly in patients with underlying neurological disorders, may lead to development of novel therapies and discovery of shared risk factors, as well as highlight the need for broad, whole-health clinical approaches toward treatment.

Indomethacin augments lipopolysaccharide-induced expression of inflammatory molecules in the mouse brain

Indomethacin and other non-steroidal anti-inflammatory drugs (NSAIDs) are used to relieve pain and fever including during infections. However, some studies suggest that NSAIDs protect against neuroinflammation, while some find no effects or worsening of neuroinflammation. We evaluated the effect of indomethacin alone on in combination with minocycline, a drug that inhibits neuroinflammation, on the expression of transcripts of neuroinflammatory molecules-induced by lipopolysaccharide (LPS) in the brain of mice. Inoculation of male BALB/c mice with LPS induced the expression of the microglia marker ionized calcium binding adaptor molecule protein, mRNA expression of the genes for cytokines interleukin-1beta (Il1b) and tumor necrosis factor-alpha (Tnf) and inducible nitric oxide synthase gene (Nos2), but not Il10, in the brain. Treatment with indomethacin had no significant effect on the cytokines or Nos2 mRNA expression in naïve animals. However, pretreatment with indomethacin increased LPS-induced Nos2 mRNA and inducible nitric oxide (iNOS) protein expression, but had no significant effect on LPS-induced mRNA expression of the cytokines. Minocycline reduced LPS-induced Il1b and Tnf, but not Nos2, mRNA expression. Treatment with indomethacin plus minocycline had no effect on LPS-induced Il1b, Tnf and Nos2 mRNA expression. In conclusion these results show that indomethacin significantly augments LPS-induced Nos2 mRNA and iNOS protein expression in the brain. In the presence of indomethacin, minocycline could not inhibit LPS-induced pro-inflammatory cytokine expression. Thus, indomethacin could exacerbate neuroinflammation by increasing the expression of iNOS and also block the anti-inflammatory effects of minocycline.

JAK/STAT signaling pathway-mediated microRNA-181b promoted blood-brain barrier impairment by targeting sphingosine-1-phosphate receptor 1 in septic rats

Background

Blood-brain barrier (BBB) impairment plays a significant role in the pathogenesis of sepsis-associated encephalopathy (SAE). However, the molecular mechanisms are poorly understood. In the present study, we aimed to investigate the regulatory relationship between the Janus kinase/signal transducers and activators of transcription (JAK/STAT) signaling pathway, microRNA (miR)-181b and its target genes in sepsis in vivo and in vitro.

Methods

Four rat models (sham, sepsis, sepsis plus STAT3 inhibitor (Stattic), and sepsis plus miR-181b inhibitor [sepsis + anta-miR-181b]) were established. For the in vitro experiments, rat brain microvascular endothelial cells (rBMECs) and rat brain astrocytes (rAstrocytes) were cultured with 10% serum harvested from sham, sepsis, and sepsis + anta-miR-181b rats. Chromatin immunoprecipitation-quantitative polymerase chain reaction (ChIP-QPCR) analysis was carried out to detect the binding and enrichment of the JAK/STAT3 signal core transcription complex in the miR-181b promoter region. Dual-luciferase reporter gene assay was conducted to test miR-181b and its target genes. The cell adhesion rate of rBMECs was also measured.

Results

During our investigations, the expression levels of miR-181b, p-JAK2, p-STAT3, and C/EBPβ were found to be significantly increased in the septic rats compared with the sham rats. STAT3 inhibitor halted BBB damage by downregulating the expression of miR-181b. In addition, miR-181b targeted sphingosine-1-phosphate receptor 1 (S1PR1) and neurocalcin delta (NCALD). The up-regulated miR-181b significantly decreased the cell adhesion rate of rBMECs. The administration of miR-181b inhibitor reduced damage to the BBB through increasing the expression of S1PR1 and NCALD, which again proved that miR-181b negatively regulates SIPR1 and NCALD to induce BBB damage.

Conclusions

Our study demonstrated that JAK2/STAT3 signaling pathway induced expression of miR-181b, which promoted BBB impairment in rats with sepsis by downregulating S1PR1 and decreasing BBB cell adhesion. These findings strongly suggest JAK2/STAT3/miR-181b axis as therapeutic target in protecting against sepsis-induced BBB damage.

Role of Systemic and Nasal Glucocorticoid Treatment in the Regulation of the Inflammatory Response in Patients with SARS-Cov-2 Infection

The Chinese outbreak of SARS-CoV-2 during 2019 has become pandemic and the most important concerns are the acute respiratory distress syndrome (ARDS) and hyperinflammation developed by the population at risk (elderly and/or having obesity, diabetes, and hypertension) in whom clinical evolution quickly progresses to multi-organ dysfunction and fatal outcome. Immune dysregulation is linked to uncontrolled proinflammatory response characterized by the release of cytokines (cytokines storm). A proper control of this response is mandatory to improve clinical prognosis. In this context, glucocorticoids are able to change the expression of several genes involved in the inflammatory response leading to an improvement in acute respiratory distress. Although there are contradictory data in the literature, in this report we highlight the potential benefits of glucocorticoids as adjuvant therapy for hyperinflammation control; emphasizing that adequate dosage, timing, and delivery are crucial to reduce the dysregulated peripheral-and neuro-inflammatory response with minimal adverse effects. We propose the use of the intranasal route for glucocorticoid administration, which has been shown to effectively control the neuro-and peripheral-inflammatory response using low doses without generating unwanted side effects.

Intranasal Dexamethasone Reduces Mortality and Brain Damage in a Mouse Experimental Ischemic Stroke Model

Neuroinflammation triggered by the expression of damaged-associated molecular patterns released from dying cells plays a critical role in the pathogenesis of ischemic stroke. However, the benefits from the control of neuroinflammation in the clinical outcome have not been established. In this study, the effectiveness of intranasal, a highly efficient route to reach the central nervous system, and intraperitoneal dexamethasone administration in the treatment of neuroinflammation was evaluated in a 60-min middle cerebral artery occlusion (MCAO) model in C57BL/6 male mice. We performed a side-by-side comparison using intranasal versus intraperitoneal dexamethasone, a timecourse including immediate (0 h) or 4 or 12 h poststroke intranasal administration, as well as 4 intranasal doses of dexamethasone beginning 12 h after the MCAO versus a single dose at 12 h to identify the most effective conditions to treat neuroinflammation in MCAO mice. The best results were obtained 12 h after MCAO and when mice received a single dose of dexamethasone (0.25 mg/kg) intranasally. This treatment significantly reduced mortality, neurological deficits, infarct volume size, blood-brain barrier permeability in the somatosensory cortex, inflammatory cell infiltration, and glial activation. Our results demonstrate that a single low dose of intranasal dexamethasone has neuroprotective therapeutic effects in the MCAO model, showing a better clinical outcome than the intraperitoneal administration. Based on these results, we propose a new therapeutic approach for the treatment of the damage process that accompanies ischemic stroke.

The Beneficial Roles of SIRT1 in Neuroinflammation-Related Diseases

Sirtuins are the class III of histone deacetylases whose deacetylate of histones is dependent on nicotinamide adenine dinucleotide (NAD+). Among seven sirtuins, SIRT1 plays a critical role in modulating a wide range of physiological processes, including apoptosis, DNA repair, inflammatory response, metabolism, cancer, and stress. Neuroinflammation is associated with many neurological diseases, including ischemic stroke, bacterial infections, traumatic brain injury, Alzheimer's disease (AD), and Parkinson's disease (PD). Recently, numerous studies indicate the protective effects of SIRT1 in neuroinflammation-related diseases. Here, we review the latest progress regarding the anti-inflammatory and neuroprotective effects of SIRT1. First, we introduce the structure, catalytic mechanism, and functions of SIRT1. Next, we discuss the molecular mechanisms of SIRT1 in the regulation of neuroinflammation. Finally, we analyze the mechanisms and effects of SIRT1 in several common neuroinflammation-associated diseases, such as cerebral ischemia, traumatic brain injury, spinal cord injury, AD, and PD. Taken together, this information implies that SIRT1 may serve as a promising therapeutic target for the treatment of neuroinflammation-associated disorders.

Intranasal Methylprednisolone Effectively Reduces Neuroinflammation in Mice With Experimental Autoimmune Encephalitis

Relapsing-remitting multiple sclerosis, the most common form, is characterized by acute neuroinflammatory episodes. In addition to continuous disease-modifying therapy, these relapses require treatment to prevent lesion accumulation and progression of disability. Intravenous methylprednisolone (1-2 g for 3-5 days) is the standard treatment for relapses. However, this treatment is invasive, requires hospitalization, leads to substantial systemic exposure of glucocorticoids, and can only reach modest concentrations in the central nervous system (CNS). Intranasal delivery may represent an alternative to deliver relapse treatment directly to the CNS with higher concentrations and reducing side effects. Histopathological analysis revealed that intranasal administration of methylprednisolone to mice with experimental autoimmune encephalomyelitis (EAE) suppressed the neuroinflammatory peak, and reduced immune cell infiltration and demyelination in the CNS similarly to intravenous administration. Treatment also downregulated Iba1 and GFAP expression. A similar significant reduction of IL-1β, IL-6, IL-17, IFN-γ, and TNF-α levels in the spinal cord was attained in both intranasal and intravenously treated mice. No damage in the nasal cavity was found after intranasal administration. This study demonstrates that intranasal delivery of methylprednisolone is as efficient as the intravenous route to treat neuroinflammation in EAE.

Clinical manifestations and evidence of neurological involvement in 2019 novel coronavirus SARS-CoV-2: a systematic review and meta-analysis

Background

Coronavirus disease 2019 (COVID-19) has become a global pandemic, affecting millions of people. However, clinical research on its neurological manifestations is thus far limited. In this study, we aimed to systematically collect and investigate the clinical manifestations and evidence of neurological involvement in COVID-19.

Methods

Three medical (Medline, Embase, and Scopus) and two preprints (BioRxiv and MedRxiv) databases were systematically searched for all published articles on neurological involvement in COVID-19 since the outbreak. All included studies were systematically reviewed, and selected clinical data were collected for meta-analysis via random-effects.

Results

A total of 41 articles were eligible and included in this review, showing a wide spectrum of neurological manifestations in COVID-19. The meta-analysis for unspecific neurological symptoms revealed that the most common manifestations were fatigue (33.2% [23.1–43.3]), anorexia (30.0% [23.2–36.9]), dyspnea/shortness of breath (26.9% [19.2–34.6]), and malaise (26.7% [13.3–40.1]). The common specific neurological symptoms included olfactory (35.7–85.6%) and gustatory (33.3–88.8%) disorders, especially in mild cases. Guillain–Barré syndrome and acute inflammation of the brain, spinal cord, and meninges were repeatedly reported after COVID-19. Laboratory, electrophysiological, radiological, and pathological evidence supported neurologic involvement of COVID-19.

Conclusions

Neurological manifestations are various and prevalent in COVID-19. Emerging clinical evidence suggests neurological involvement is an important aspect of the disease. The underlying mechanisms can include both direct invasion and maladaptive inflammatory responses. More studies should be conducted to explore the role of neurological manifestations in COVID-19 progression and to verify their underlying mechanisms.

Electronic supplementary material

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Staphylococcus epidermidis Sensitizes Perinatal Hypoxic-Ischemic Brain Injury in Male but Not Female Mice

Background: Staphylococcus epidermidis is the most common nosocomial infection and the predominant pathogen in late-onset sepsis in preterm infants. Infection and inflammation are linked to neurological and developmental sequelae and bacterial infections increase the vulnerability of the brain to hypoxia-ischemia (HI). We thus tested the hypothesis that S. epidermidis exacerbates HI neuropathology in neonatal mice. Methods: Male and female C57Bl/6 mice were injected intraperitoneally with sterile saline or 3.5 × 10⁷ colony-forming units of S. epidermidis on postnatal day (PND) 4 and then subjected to HI on PND5 (24 h after injection) or PND9 (5 d after injection) by left carotid artery ligation and exposure to 10% O₂. White and gray matter injury was assessed on PND14-16. In an additional group of animals, the plasma, brain, and liver were collected on PND5 or PND9 after infection to evaluate cytokine and chemokine profiles, C5a levels and C5 signaling. Results: HI induced 24 h after injection of S. epidermidis resulted in greater gray and white matter injury compared to saline injected controls in males, but not in females. Specifically, males demonstrated increased gray matter injury in the cortex and striatum, and white matter loss in the subcortical region, hippocampal fimbria and striatum. In contrast, there was no potentiation of brain injury when HI occurred 5 d after infection in either sex. In the plasma, S. epidermidis-injected mice demonstrated increased levels of pro- and anti-inflammatory cytokines and chemokines and a reduction of C5a at 24 h, but not 5 d after infection. Brain CCL2 levels were increased in both sexes 24 h after infection, but increased only in males at 5 d post infection. Conclusion: Ongoing S. epidermidis infection combined with neonatal HI increases the vulnerability of the developing brain in male but not in female mice. These sex-dependent effects were to a large extent independent of expression of systemic cytokines or brain CCL2 expression. Overall, we provide new insights into how systemic S. epidermidis infection affects the developing brain and show that the time interval between infection and HI is a critical sensitizing factor in males.