Gut-brain axis in the pathogenesis of sepsis-associated encephalopathy.

The gut-brain axis is a bidirectional communication network linking the gut and the brain, overseeing digestive functions, emotional responses, body immunity, brain development, and overall health. Substantial research highlights a connection between disruptions of the gut-brain axis and various psychiatric and neurological conditions, including depression and Alzheimer's disease. Given the impact of the gut-brain axis on behavior, cognition, and brain diseases, some studies have started to pay attention to the role of the axis in sepsis-associated encephalopathy (SAE), where cognitive impairment is the primary manifestation. SAE emerges as the primary and earliest form of organ dysfunction following sepsis, potentially leading to acute cognitive impairment and long-term cognitive decline in patients. Notably, the neuronal damage in SAE does not stem directly from the central nervous system (CNS) infection but rather from an infection occurring outside the brain. The gut-brain axis is posited as a pivotal factor in this process. This review will delve into the gut-brain axis, exploring four crucial pathways through which inflammatory signals are transmitted and elevate the incidence of SAE. These pathways encompass the vagus nerve pathway, the neuroendocrine pathway involving the hypothalamic-pituitary-adrenal (HPA) axis and serotonin (5-HT) regulation, the neuroimmune pathway, and the microbial regulation. These pathways can operate independently or collaboratively on the CNS to modulate brain activity. Understanding how the gut affects and regulates the CNS could offer the potential to identify novel targets for preventing and treating this condition, ultimately enhancing the prognosis for individuals with SAE.

The early predictive roles of NLR and NE% in in-hospital mortality of septic patients.

Background: This study aimed to retrospectively investigate the early predictive value of inflammation-related parameters in-hospital mortality of septic patients. Methods: We retrospectively recruited 606 patients from Wuhan Union Hospital from January 2009 to October 2022. The inflammation-related parameters including neutrophil-to-lymphocyte ratio (NLR), neutrophil percentage (NE%), platelet-to-lymphocyte ratio (PLR), and monocyte-to-lymphocyte ratio (MLR) in survivals and non-survivals on day 1, 2, 3 and 7 after hospitalization were collected and analyzed. Results: NLR and NE% in non-survivals (n = 185) were significantly higher than those in survivals (n = 421). The area under the receiver operating characteristic curve (AUC) of NLR or NE% was 0.880 or 0.852 on day 1, 0.770 or 0.790 on day 2, 0.784 or 0.777 on day 3, and 0.732 or 0.741 on day 7. The optimal cut-off values of NLR or NE% for predicting in-hospital mortality were 10.769 or 87.70% on day 1, 17.544 or 90.69% on day 2, 14.395 or 85.00% on day 3, and 9.105 or 83.93% on day 7. The day 1, 2 and 3 NLR and NE% were significant predictors of in-hospital mortality in the Cox proportional hazards models. Conclusions: NLR ≥10.769 and NE% ≥ 87.70% could be used early biomarkers for predicting in-hospital mortality of septic patients.

Aldehyde Dehydrogenase 2 Preserves Mitochondrial Function in the Ischemic Heart: A Redox-dependent Mechanism for AMPK Activation by Thioredoxin-1.

ABSTRACT: Aldehyde dehydrogenase 2 (ALDH2) protects the ischemic heart by activating adenosine 5'-monophosphate-activated protein kinase (AMPK) signaling. However, the molecular mechanisms linking ALDH2 and AMPK signaling are not fully understood. This study aimed to explore the potential mechanisms linking ALDH2 and AMPK in myocardial ischemic injury. An ischemic model was established by ligating the left anterior descending coronary artery in rats. The overexpression or knockdown of ALDH2 in H9c2 cells treated with oxygen-glucose deprivation was obtained through lentivirus infection. Transferase-mediated dUTP nick-end labeling was used to evaluate apoptosis in an ischemic rat model and oxygen-glucose deprivation cells. ALDH2 activity, mitochondrial oxidative stress markers, adenosine triphosphate, respiratory control ratio, and cell viability in H9c2 cells were evaluated using a biological kit and 3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyl tetrazolium bromide. Protein expression of ALDH2 , 4-hydroxynonenal, thioredoxin-1 (Trx-1), and AMPK-proliferator-activated receptor gamma coactivator-1 alpha (PGC-1α) signaling pathway was detected through Western blotting. ALDH2 activation reduced ischemic-induced myocardial infarct size and apoptosis. ALDH2 protected mitochondrial function by enhancing mitochondrial respiratory control ratio and adenosine triphosphate production, alleviated mitochondrial oxidative stress, and suppressed myocardial apoptosis. Moreover, ALDH2 attenuated ischemia-induced oxidative stress and maintained Trx-1 levels by reducing 4-hydroxynonenal, thereby promoting AMPK-PGC-1α signaling activation. Inhibiting Trx-1 or AMPK abolished the cardioprotective effect of ALDH2 on ischemia. ALDH2 alleviates myocardial injury through increased mitochondrial biogenesis and reduced oxidative stress, and these effects were achieved through Trx1-mediating AMPK-PGC1-α signaling activation.

Esketamine mitigates cognitive impairment following exposure to LPS by modulating the intestinal flora/subdiaphragmatic vagus nerve/spleen axis.

INTRODUCTION: Susceptibility to secondary infection often increases after primary infection. Secondary infections can lead to more severe inflammatory injuries; however, the underlying mechanisms are not yet fully elucidated. OBJECTIVE: To investigate whether esketamine treatment immediately after primary lipopolysaccharide (LPS) exposure could alleviate cognitive impairment caused by secondary infection. METHODS: Mice were injected intraperitoneally (IP) with LPS (5 mg/kg) 10 days apart. Esketamine (10, 15, or 30 mg/kg) was administered IP immediately after the primary LPS injection. Splenectomy or subdiaphragmatic vagotomy (SDV) was performed 7 days before secondary LPS exposure or broad-spectrum antibiotic administration. RESULTS: Splenomegaly was observed after the primary LPS injection on Days 3 and 10. Splenomegaly was attenuated by treatment with 30 mg/kg esketamine. Esketamine treatment prevented increased plasma proinflammatory cytokines levels and cognitive dysfunction induced by secondary LPS exposure. Mice that underwent splenectomy or SDV had lower proinflammatory cytokines levels, higher hippocampal brain-derived neurotrophic factor (BDNF) levels, and improved cognitive function 1 day after secondary infection, which was not further improved by esketamine. Fecal microbiota transplantation (FMT) from endotoxic mice treated with esketamine attenuated hippocampal BDNF downregulation and cognitive dysfunction only in pseudo germ-free (PGF) mice without splenectomy. FMT with fecal suspensions from esketamine-treated endotoxic mice abrogated splenomegaly only in PGF mice without SDV. Blocking BDNF signaling blocked esketamine's ameliorating effects on secondary LPS exposure-induced cognitive dysfunction. CONCLUSION: The intestinal flora/subdiaphragmatic vagus nerve/spleen axis-mediated hippocampal BDNF downregulation significantly affected secondary LPS-induced systemic inflammation and cognitive dysfunction. Esketamine preserves cognitive function via this mechanism.

Remimazolam besylate versus propofol for deep sedation in critically ill patients: a randomized pilot study.

OBJECTIVE: To compare the efficacy and safety of remimazolam besylate and propofol for deep sedation in critically ill patients. METHODS: In this single-center, prospective, randomized, controlled pilot study, patients in the intensive care unit (ICU) requiring deep sedation were randomized to receive remimazolam besylate or propofol intravenously. Deep sedation was defined as a Richmond Agitation and Sedation Scale (RASS) score of - 4 or - 5. Sedation depth was monitored using RASS and Narcotrend Index (NI). The primary outcome was the percentage of time within the target sedation range without rescue sedation. The secondary outcomes included ventilator-free hours within 7 days, successful extubation, length of ICU stay, and 28-day mortality. Adverse events during the interventional period were also recorded. RESULTS: Thirty patients were assigned to each group. The median (IQR) RASS score was - 5.0 (- 5.0, - 4.0), and the median (IQR) NI value was 29.0 (21.0, 37.0) during the intervention period. Target RASS was reached a median of 100% of the sedation time in the two groups. No significant differences were observed in ventilator-free hours within 7 days, successful extubation, length of ICU stay, or 28-day mortality among groups. Hypotension occurred in 16 (53.3%) patients of remimazolam group and 18 (60.0%) patients of propofol group (p > 0.05). No patient experienced bradycardia. CONCLUSIONS: Remimazolam besylate appears to be an effective and safe agent for short-term deep sedation in critically ill patients. Our findings warrant large sample-sized randomized clinical trials.

Relationship of close contact settings with transmission and infection during the SARS-CoV-2 Omicron BA.2 epidemic in Shanghai.

INTRODUCTION: We analysed case-contact clusters during the Omicron BA.2 epidemic in Shanghai to assess the risk of infection of contacts in different settings and to evaluate the effect of demographic factors on the association of infectivity and susceptibility to the Omicron variant. METHODS: Data on the settings and frequency of contact, demographic characteristics and comorbidities of index cases, contacts and secondary cases were analysed. Independent effect of multiple variables on the risk for transmission and infection was evaluated using generalised estimating equations. RESULTS: From 1 March to 1 June 2022, we identified 450 770 close contacts of 90 885 index cases. The risk for infection was greater for contacts in farmers' markets (fixed locations where farmers gather to sell products, adjusted OR (aOR): 3.62; 95% CI 2.87 to 4.55) and households (aOR: 2.68; 95% CI 2.15 to 3.35). Children (0-4 years) and elderly adults (60 years and above) had higher risk for infection and transmission. During the course of the epidemic, the risk for infection and transmission in different age groups initially increased, and then decreased on about 21 April (17th day of citywide home quarantine). Compared with medical workers (reference, aOR: 1.00), unemployed contacts (aOR: 1.77; 95% CI 1.53 to 2.04) and preschoolers (aOR: 1.61; 95% CI 1.26 to 2.05) had the highest risk for infection; delivery workers (aOR: 1.90, 95% CI 1.51 to 2.40) and public service workers (aOR: 1.85; 95% CI 1.64 to 2.10) had the highest risk for transmission. Contacts who had comorbidities (aOR: 1.10; 95% CI 1.09 to 1.12) had a higher risk for infection, particularly those with lung diseases or immune deficiency. CONCLUSION: Farmers' markets and households were the main setting for transmission of Omicron. Children, the elderly, delivery workers and public service workers had the highest risk for transmission and infection. These findings should be considered when implementing targeted interventions.

Anisodamine hydrobromide in the treatment of critically ill patients with septic shock: a multicenter randomized controlled trial.

BACKGROUND: Septic shock is the development of sepsis to refractory circulatory collapse and metabolic derangements, characterized by persistent hypotension and increased lactate levels. Anisodamine hydrobromide (Ani HBr) is a Chinese medicine used to improve blood flow in circulatory disorders. The purpose of this study was to determine the therapeutic efficacy of Ani HBr in the treatment of patients with septic shock. METHODS: This was a prospective, multicenter, randomized controlled trial focusing on patients with septic shock in 16 hospitals in China. Patients were randomly assigned in a 1:1 ratio to either the treatment group or the control group. The primary endpoint was 28-day mortality. The secondary outcomes included 7-day mortality, hospital mortality, hospital length of stay, vasopressor-free days within 7 days, etc. These indicators were measured and collected at 0, 6h, 24h, 48h, 72h and 7d after the diagnosis. RESULTS: Between September 2017 and March 2021, 404 subjects were enrolled. 203 subjects received Ani HBr and 201 subjects were assigned to the control group. The treated group showed lower 28-day mortality than the control group. Stratified analysis further showed significant differences in 28-day mortality between the two groups for patients with a high level of illness severity. We also observed significant differences in 7-day mortality, hospital mortality and some other clinical indicators between the two groups. CONCLUSION: Ani HBr might be an important adjuvant to conventional treatment to reduce 28-day mortality in patients with septic shock. A large-scale prospective randomized multicenter trial is warranted to confirm our results.

Diterpenoids from Euphorbia fischeriana with Kv1.3 Inhibitory Activity.

Euphorbia diterpenoids possess inhibitory effects of Kv1.3 ion channel, but most of this research has focused on diterpenoids with jatrophane-related or ingenane-related skeletons. In the present study, nine undescribed (1-9) and 16 known (10-25) diterpenoids, based on jatrophane, lathyrane, ingenane, abietane, and atisane skeletons, were identified from the methanol extract of the aerial parts of Euphorbia fischeriana. The structures were established by analysis of the spectroscopic data as well as by single-crystal X-ray diffraction analysis. Among the isolated diterpenoids, macrocyclic jatrophanes and lathyranes exerted Kv1.3 blocking activity. Compound 8 exhibited good selectivity on the inhibition of the Kv 1.3 channel rather than hERG channel, with a selectivity index over 7.0. The selective activity of lathyrane diterpenoids indicates that macrocyclic diterpenoids have the potential to be further investigated as therapeutic agents for the treatment of autoimmune diseases.

Long-term sedation with remimazolam besylate versus propofol in critically ill patients during invasive mechanical ventilation: a study protocol for a multicenter randomized non-inferior trial.

Background: Remimazolam besylate is a novel ultra-short-acting benzodiazepine that can potentially be a safe and effective sedative in intensive care units. This study aims to assess whether remimazolam besylate is not inferior to propofol in maintaining mild-to-moderate sedation in critically ill patients receiving long-term mechanical ventilation. Methods and analysis: This is a multicenter, randomized, single-blind, propofol-controlled, non-inferiority study. Eligible patients are randomly assigned to receive remimazolam besylate or propofol in a 1:1 ratio to maintain a Richmond Agitation-Sedation Scale score between -3 and 0. When patients are under-sedated, rescue sedation of dexmedetomidine is added. The primary outcome is the percentage of time in the target sedation range. The secondary outcomes are hours free from the invasive ventilator in 7 days, successful extubation in 7 days, and weaning time, the length of intensive care unit stay, the length of hospital stay, and mortality in 28 days. Modified intention-to-treat and safety analysis is performed. Clinical trial registration number: https://clinicaltrials.gov/ct2/show/NCT05555667.

[Expert consensus on implementation strategy of awake prone positioning for non-intubated patients in China (2023)].

The awake prone position plays an important role in the treatment of hypoxemia and the improvement of respiratory distress symptoms in non-intubated patients. It is widely used in clinical practice because of its simple operation, safety, and economy. To enable clinical medical staff to scientifically and normatively implement prone position for awake patients without intubation, the committees of consensus formulation, guided by evidence-based methodology and Delphi method, conducted literature search, literature quality evaluation and evidence synthesis around seven topics, including indications and contraindications, evaluation, implementation, monitoring and safety management, termination time, complication prevention and health education of awake prone position. After two rounds of expert letter consultation, Expert consensus on implementation strategy of awake prone positioning for non-intubated patients in China (2023) was formulated, and provide guidance for clinical medical staff.

Abnormal glucose metabolism in virus associated sepsis.

Sepsis is identified as a potentially lethal organ impairment triggered by an inadequate host reaction to infection (Sepsis-3). Viral sepsis is a potentially deadly organ impairment state caused by the host's inappropriate reaction to a viral infection. However, when a viral infection occurs, the metabolism of the infected cell undergoes a variety of changes that cause the host to respond to the infection. But, until now, little has been known about the challenges faced by cellular metabolic alterations that occur during viral infection and how these changes modulate infection. This study concentrates on the alterations in glucose metabolism during viral sepsis and their impact on viral infection, with a view to exploring new potential therapeutic targets for viral sepsis.

Effects of airway pressure release ventilation on lung physiology assessed by electrical impedance tomography in patients with early moderate-to-severe ARDS.

OBJECTIVE: The aim of this study was to investigate the physiological impact of airway pressure release ventilation (APRV) on patients with early moderate-to-severe acute respiratory distress syndrome (ARDS) by electrical impedance tomography (EIT). METHODS: In this single-center prospective physiological study, adult patients with early moderate-to-severe ARDS mechanically ventilated with APRV were assessed by EIT shortly after APRV (T0), and 6 h (T1), 12 h (T2), and 24 h (T3) after APRV initiation. Regional ventilation and perfusion distribution, dead space (%), shunt (%), and ventilation/perfusion matching (%) based on EIT measurement at different time points were compared. Additionally, clinical variables related to respiratory and hemodynamic condition were analyzed. RESULTS: Twelve patients were included in the study. After APRV, lung ventilation and perfusion were significantly redistributed to dorsal region. One indicator of ventilation distribution heterogeneity is the global inhomogeneity index, which decreased gradually [0.61 (0.55-0.62) to 0.50 (0.42-0.53), p < 0.001]. The other is the center of ventilation, which gradually shifted towards the dorsal region (43.31 ± 5.07 to 46.84 ± 4.96%, p = 0.048). The dorsal ventilation/perfusion matching increased significantly from T0 to T3 (25.72 ± 9.01 to 29.80 ± 7.19%, p = 0.007). Better dorsal ventilation (%) was significantly correlated with higher PaO2/FiO2 (r = 0.624, p = 0.001) and lower PaCO2 (r = -0.408, p = 0.048). CONCLUSIONS: APRV optimizes the distribution of ventilation and perfusion, reducing lung heterogeneity, which potentially reduces the risk of ventilator-induced lung injury.

Reversal of the detrimental effects of social isolation on ischemic cerebral injury and stroke-associated pneumonia by inhibiting small intestinal γδ T-cell migration into the brain and lung.

Social isolation (ISO) is associated with an increased risk and poor outcomes of ischemic stroke. However, the roles and mechanisms of ISO in stroke-associated pneumonia (SAP) remain unclear. Adult male mice were single- or pair-housed with an ovariectomized female mouse and then subjected to transient middle cerebral artery occlusion. Isolated mice were treated with the natriuretic peptide receptor A antagonist A71915 or anti-gamma-delta (γδ) TCR monoclonal antibody, whereas pair-housed mice were treated with recombinant human atrial natriuretic peptide (rhANP). Subdiaphragmatic vagotomy (SDV) was performed 14 days before single- or pair-housed conditions. We found that ISO significantly worsened brain and lung injuries relative to pair housing, which was partially mediated by elevated interleukin (IL)-17A levels and the migration of small intestine-derived inflammatory γδ T-cells into the brain and lung. However, rhANP treatment or SDV could ameliorate ISO-exacerbated post-stroke brain and lung damage by reducing IL-17A levels and inhibiting the migration of inflammatory γδ T-cells into the brain and lung. Our results suggest that rhANP mitigated ISO-induced exacerbation of SAP and ischemic cerebral injury by inhibiting small intestine-derived γδ T-cell migration into the lung and brain, which could be mediated by the subdiaphragmatic vagus nerve.

Mechanosensitive ion channel Piezo1 mediates mechanical ventilation-exacerbated ARDS-associated pulmonary fibrosis.

INTRODUCTION: Pulmonary fibrosis is a major cause of the poor prognosis of acute respiratory distress syndrome (ARDS). While mechanical ventilation (MV) is an indispensable life-saving intervention for ARDS, it may cause the remodeling process in lung epithelial cells to become disorganized and exacerbate ARDS-associated pulmonary fibrosis. Piezo1 is a mechanosensitive ion channel that is known to play a role in regulating diverse physiological processes, but whether Piezo1 is necessary for MV-exacerbated ARDS-associated pulmonary fibrosis remains unknown. OBJECTIVES: This study aimed to explore the role of Piezo1 in MV-exacerbated ARDS-associated pulmonary fibrosis. METHODS: Human lung epithelial cells were stimulated with hydrochloric acid (HCl) followed by mechanical stretch for 48 h. A two-hitmodel of MV afteracidaspiration-inducedlunginjuryin mice was used. Mice were sacrificed after 14 days of MV. Pharmacological inhibition and knockout of Piezo1 were used to delineate the role of Piezo1 in MV-exacerbated ARDS-associated pulmonary fibrosis. In some experiments, ATP or the ATP-hydrolyzing enzyme apyrase was administered. RESULTS: The stimulation of human lung epithelial cells to HCl resulted in phenotypes of epithelial-mesenchymal transition (EMT), which were enhanced by mechanical stretching. MV exacerbated pulmonary fibrosis in mice exposed to HCl. Pharmacologicalinhibitionorknockout of Piezo1 attenuated the MV-exacerbated EMT process and lung fibrosis in vivo and in vitro. Mechanistically, the observed effects were mediated by Piezo1-dependent Ca2+ influx and ATP release in lung epithelial cells. CONCLUSIONS: Our findings identify a key role for Piezo1 in MV-exacerbated ARDS-associated pulmonary fibrosis that is mediated by increased ATP release in lung epithelial cells. Inhibiting Piezo1 may constitute a novelstrategyfor the treatment of MV-exacerbated ARDS-associated pulmonary fibrosis.

Associations between HIV infection and frailty status and its individual components: Are frailty components disproportionally affected?

OBJECTIVE: We aimed to examine whether HIV infection was independently associated with frailty status and its individual components. METHODS: This cross-sectional investigation included people living with HIV (PLWH) and HIV-negative individuals from the baseline survey of the Comparative HIV and Aging Research in Taizhou (CHART) cohort, China. Frailty phenotype was based on five components: weight loss, low physical activity, exhaustion, weak grip strength and slow gait speed. Frailty was defined as the presence of at least three components, and prefrailty was defined as one or two components. Logistic regression models were used to analyse the factors associated with frailty and its components. RESULTS: In all, 2475 people living with HIV (age 45.5 ± 14.9 years; 76.2% male) and 4948 HIV-negative individuals (age 45.5 ± 14.8 years; 76.3% male) were included. Among PLWH, median CD4 count was 395 cells/µL and 78% were currently on antiretroviral therapy (ART). Frailty and prefrailty were significantly more prevalent in PLWH (3.2% vs 1.9% and 32.9% vs 27.9%) overall and at ages 18-39 (1.4% vs 0.2% and 22.7% vs 19.0%), 40-59 (2.5% vs 0.9% and 30.9% vs 27.9%) and 60-90 years (8.4% vs 7.4% and 57.1% vs 45.8%). HIV infection was associated with frailty and prefrailty [adjusted odds ratio (aOR) = 1.48, 95% confidence interval (CI): 1.06-2.08; and aOR = 1.18, 95% CI: 1.05-1.33, respectively] after adjusting for confounding variables, but were strengthened with further adjustment for multimorbidity (aOR = 1.62, 95% CI: 1.14-2.28; and aOR = 1.22, 95% CI: 1.09-1.37), and were no longer significant with further adjustment for depressive symptoms and sleep disorders (aOR = 1.02, 95% CI: 0.71-1.46; and aOR = 1.06, 95% CI: 0.94-1.20). Among individual components, HIV infection was positively associated with weak grip strength and slow gait speed, but negatively associated with low physical activity and exhaustion in all the adjusted models described. CONCLUSIONS: Frailty and prefrailty occur more often and earlier in PLWH. However, grip strength and gait speed are affected to a greater extent, highlighting their potential as screening and intervention targets to prevent or slow frailty among PLWH.

NLRC3 expression in macrophage impairs glycolysis and host immune defense by modulating the NF-κB-NFAT5 complex during septic immunosuppression.

Impairment of innate immune cell function and metabolism underlies immunosuppression in sepsis; however, a promising therapy to orchestrate this impairment is currently lacking. In this study, high levels of NOD-like receptor family CARD domain containing-3 (NLRC3) correlated with the glycolytic defects of monocytes/macrophages from septic patients and mice that developed immunosuppression. Myeloid-specific NLRC3 deletion improved macrophage glycolysis and sepsis-induced immunosuppression. Mechanistically, NLRC3 inhibits nuclear factor (NF)-κB p65 binding to nuclear factor of activated T cells 5 (NFAT5), which further controls the expression of glycolytic genes and proinflammatory cytokines of immunosuppressive macrophages. This is achieved by decreasing NF-κB activation-co-induced by TNF-receptor-associated factor 6 (TRAF6) or mammalian target of rapamycin (mTOR)-and decreasing transcriptional co-activator p300 activity by inducing NLRC3 sequestration of mTOR and p300. Genetic inhibition of NLRC3 disrupted the NLRC3-mTOR-p300 complex and enhanced NF-κB binding to the NFAT5 promoter in concert with p300. Furthermore, intrapulmonary delivery of recombinant adeno-associated virus harboring a macrophage-specific NLRC3 deletion vector significantly improved the defense of septic mice that developed immunosuppression upon secondary intratracheal bacterial challenge. Collectively, these findings indicate that NLRC3 mediates critical aspects of innate immunity that contribute to an immunocompromised state during sepsis and identify potential therapeutic targets.

Remimazolam besylate for the sedation of postoperative patients undergoing invasive mechanical ventilation in the ICU: a prospective dose‒response study.

This single-center study aimed to determine the effective dose and safety of remimazolam besylate for the sedation of postoperative patients undergoing invasive mechanical ventilation in the intensive care unit (ICU). Mechanically ventilated patients admitted to the ICU after surgery were included. The Narcotrend index (NTI) was used to assess the depth of sedation, and the Richmond Agitation-Sedation Scale (RASS) score was also recorded. Remimazolam besylate was administered initially at a loading dose of 0.02 mg/kg, followed by a gradual increase of 0.005 mg/kg each time until the targeted depth of sedation was achieved (NTI 65-94). A maintenance dose of remimazolam besylate was administered starting at 0.2 mg/kg/h, followed by increments or subtractions of 0.05 mg/kg/h each time until a satisfactory depth of sedation was achieved and maintained for at least 30 min. The demographic data, anesthesia, surgery types, hemodynamics and respiratory parameters were recorded. Adverse events and adverse drug reactions were monitored for safety. Twenty-three patients were eventually included in this study covering a period of 1 year. A satisfactory depth of sedation was achieved by a single intravenous infusion of remimazolam besylate at a loading dose of 0.02-0.05 mg/kg followed by a maintenance dose of 0.20-0.35 mg/kg/h. There were no significant changes in hemodynamic and respiratory parameters within 10 min after the administration of remimazolam besylate. In addition, a significant correlation was observed between the NTI and the RASS score for assessing sedation (r = 0.721, P < 0.001). The NTI showed a predictive probability for a RASS score of 0.817. Remimazolam besylate was effective for mild/moderate sedation of invasively mechanically ventilated postoperative patients in the ICU while maintaining excellent respiratory and hemodynamic stability. The NTI can be used as a good tool for the objective evaluation of the depth of sedation and agitation.

Cardiac-targeted PIASy gene silencing mediates deSUMOylation of caveolin-3 and prevents ischemia/reperfusion-induced Nav1.5 downregulation and ventricular arrhythmias.

BACKGROUND: Abnormal myocardial Nav1.5 expression and function cause lethal ventricular arrhythmias during myocardial ischemia-reperfusion (I/R). Protein inhibitor of activated STAT Y (PIASy)-mediated caveolin-3 (Cav-3) SUMO modification affects Cav-3 binding to the voltage-gated sodium channel 1.5 (Nav1.5). PIASy activity is increased after myocardial I/R, but it is unclear whether this is attributable to plasma membrane Nav1.5 downregulation and ventricular arrhythmias. METHODS: Using recombinant adeno-associated virus subtype 9 (AAV9), rat cardiac PIASy was silenced using intraventricular injection of PIASy short hairpin RNA (shRNA). After two weeks, rat hearts were subjected to I/R and electrocardiography was performed to assess malignant arrhythmias. Tissues from peri-infarct areas of the left ventricle were collected for molecular biological measurements. RESULTS: PIASy was upregulated by I/R (P < 0.01), with increased SUMO2/3 modification of Cav-3 and reduced membrane Nav1.5 density (P < 0.01). AAV9-PIASy shRNA intraventricular injection into the rat heart downregulated PIASy after I/R, at both mRNA and protein levels (P < 0.05 vs. Scramble-shRNA + I/R group), decreased SUMO-modified Cav-3 levels, enhanced Cav-3 binding to Nav1.5, and prevented I/R-induced decrease of Nav1.5 and Cav-3 co-localization in the intercalated disc and lateral membrane. PIASy silencing in rat hearts reduced I/R-induced fatal arrhythmias, which was reflected by a modest decrease in the duration of ventricular fibrillation (VF; P < 0.05 vs. Scramble-shRNA + I/R group) and a significantly reduced arrhythmia score (P < 0.01 vs. Scramble-shRNA + I/R group). The anti-arrhythmic effects of PIASy silencing were also evidenced by decreased episodes of ventricular tachycardia (VT), sustained VT and VF, especially at the time 5-10 min after ischemia (P < 0.05 vs. Scramble-shRNA + IR group). Using in vitro human embryonic kidney 293 T (HEK293T) cells and isolated adult rat cardiomyocyte models exposed to hypoxia/reoxygenation (H/R), we confirmed that increased PIASy promoted Cav-3 modification by SUMO2/3 and Nav1.5/Cav-3 dissociation after H/R. Mutation of SUMO consensus lysine sites in Cav-3 (K38R or K144R) altered the membrane expression levels of Nav1.5 and Cav-3 before and after H/R in HEK293T cells. CONCLUSIONS: I/R-induced cardiac PIASy activation increased Cav-3 SUMOylation by SUMO2/3 and dysregulated Nav1.5-related ventricular arrhythmias. Cardiac-targeted PIASy silencing mediated Cav-3 deSUMOylation and partially prevented I/R-induced Nav1.5 downregulation in the plasma membrane of cardiomyocytes, and subsequent ventricular arrhythmias in rats. PIASy was identified as a potential therapeutic target for life-threatening arrhythmias in patients with ischemic heart diseases.