Sepsis-induced inflammasome impairment facilitates development of secondary A. baumannii pneumonia

BACKGROUND

Acinetobacter baumannii has become one of the most critical pathogens causing nosocomial pneumonia. Existing animal models of A. baumannii pneumonia are not relevant to the majority of critical care patients. We aimed to develop a novel model of secondary A. baumannii pneumonia in post-sepsis mice.

METHODS

A two-hit model of sepsis induced by cecal ligation and puncture followed by A. baumannii pneumonia on day 5 was established. In addition, the two-hit model was established in humanized mice. A period of 2 h of mechanical ventilation followed by observation was used in additional experiments. Lung histopathology, bacterial cultures, and cellular infiltration were analysed as well as markers of the inflammasome activity in vivo and ex vivo.

RESULTS

A. baumannii infection caused mortality and loss of body weight and temperature in post-sepsis mice. Increased lung bacterial burden and dissemination together with signs of enhanced inflammatory injury were observed in post-sepsis mice but not control mice that were challenged with A. baumannii. Post-sepsis mice were unable to mount inflammasome activation in response to secondary pneumonia to the level of control mice. Transfer of wild-type but not capsase-1 KO alveolar macrophages was able to restore the pulmonary protection against A. baumannii. Mechanical ventilation exacerbated the pathological response to pneumonia in post-sepsis mice but enhanced inflammasome signalling in non-sepsis mice with pneumonia.

CONCLUSIONS

We established a novel model of A. baumannii pneumonia that revealed sepsis-induced impairment of inflammasome activation in alveolar macrophages is critical for the control of secondary A. baumannii pneumonia.

The Gut in Critical Illness

PURPOSE OF REVIEW

The purpose of this narrative review is to describe the mechanisms for gut dysfunction during critical illness, outline hypotheses of gut-derived inflammation, and identify nutrition and non-nutritional therapies that have direct and indirect effects on preserving both epithelial barrier function and gut microbiota during critical illness.

RECENT FINDINGS

Clinical and animal model studies have demonstrated that critical illness pathophysiology and interventions breach epithelial barrier function and convert a normally commensal gut microbiome into a pathobiome. As a result, the gut has been postulated to be the "motor" of critical illness and numerous hypotheses have been put forward to explain how it contributes to systemic inflammation and drives multiple organ failure. Strategies to ameliorate gut dysfunction have focused on maintaining gut barrier function and promoting gut microbiota commensalism. The trajectory of critical illness may be closely related to gut epithelial barrier function, the gut microbiome and interventions that may contribute towards a deleterious pathobiome with immune dysregulation.

Norepinephrine Infusion and the Central Venous Waveform in a Porcine Model of Endotoxemic Hypotension with Resuscitation: A Large Animal Study

BACKGROUND

Venous waveform analysis is an emerging technique to estimate intravascular fluid status by fast Fourier transform deconvolution. Fluid status has been shown proportional to f0, the amplitude of the fundamental frequency of the waveform's cardiac wave upon deconvolution. Using a porcine model of distributive shock and fluid resuscitation, we sought to determine the influence of norepinephrine on f0 of the central venous waveform.

METHODS

Eight pigs were anesthetized, catheterized and treated with norepinephrine after precipitation of endotoxemic hypotension, and subsequent fluid resuscitation to mimic sepsis physiology. Hemodynamic parameters and central venous waveforms were continually transduced throughout the protocol for post-hoc analysis. Central venous waveform f0 before, during and after norepinephrine administration were determined using Fourier analysis.

RESULTS

Heart rate increased, while central venous pressure, pulmonary capillary wedge pressure and stroke volume decreased throughout norepinephrine administration (p < 0.05). Mean f0 at pre-norepinephrine, and doses 0.05, 0.10, 0.15, 0.20 and 0.25 mcg/kg/min, were 2.5, 1.4, 1.7, 1.7, 1.6 and 1.4 mmHg2, respectively (repeated measures ANOVA; p < 0.001). On post-hoc comparison to pre-norepinephrine, f0 at 0.05 mcg/kg/min was decreased (p = 0.04).

CONCLUSIONS

As the performance of f0 was previously characterized during fluid administration, these data offer novel insight into the performance of f0 during vasopressor delivery. Central venous waveform f0 is a decreased with norepinephrine, in concordance with pulmonary capillary wedge pressure. This allows contextualization of the novel, venous-derived signal f0 during vasopressor administration, a finding that must be understood prior to clinical translation.

Extracorporeal therapies for post-liver transplant recipient: The road less traveled

Extracorporeal therapies have a definite role in patients with acute liver failure, acute on-chronic liver failure, and progressive chronic liver disease. They act as a bridge-to-transplant in these patients. With the increasing success of liver transplantation, the immediate postoperative complication spectrum continues to expand. Extracorporeal therapies can play an important role in managing these complications. However, the literature on extracorporeal therapies in the post-liver transplant period is limited. This review article discussed various extracorporeal therapies that are still evolving or marred by limited evidence but can improve patient outcomes. These extracorporeal therapies can be divided into two subgroups: (1) Therapies for infective complications. Endotoxin and cytokine adsorption columns; and (2) Therapies for noninfective complications like small for size syndrome, primary allograft nonfunction, early allograft dysfunction, hyperacute rejection, hepatopulmonary syndrome, etc. (plasma exchange, double plasma molecular adsorption, molecular adsorbent recirculation system, and extracorporeal membrane oxygenation, among others).

Ni(II) complexes of His2 peptides as multi-responsive electrochemical probes for anion sensing

Peptides possessing a histidine residue at the second position (His2) exhibit distinctive coordination properties, effectively binding transition metal cations. The resulting complexes, with labile binding sites, offer advantageous features as potential molecular receptors. In this work, a His2 peptide library was designed to select a sequence that, upon binding Ni(II) ions, would exhibit the most promising properties for anion sensing. Electrochemical techniques were used to characterize the redox properties of the studied Ni(II)-His2 peptide complexes. Subsequently, voltammetric responses of the complexes in the presence of various biologically relevant anions (chlorides, sulfates, acetates, lactates and phosphates) were collected and analyzed using Principal Component Analysis, providing effective anion discrimination based on electrochemical fingerprints. Finally, a simple methodology was proposed to differentiate varying lactate and phosphate concentrations in complex, multi-ion samples, simulating physiological and pathological blood plasma conditions. The results confirm the high application potential of the proposed class of molecular receptors and provide insights into novel anion-sensing strategies utilizing metal-peptide complexes as multi-responsive electrochemical probes.

Lipocalin 2 mediates kidney function abnormalities induced by ischemic stroke in mice: Involvement of neural pathways

BACKGROUND

Kidney function abnormalities is a common complication following ischemic stroke. Lipocalin 2 (LCN2) is currently a well-recognized specific biomarker of tubular injury. However, the role of LCN2 in kidney function abnormalities following stroke remains elusive. The sympathetic nervous system plays a crucial role in linking the brain and kidney. However, whether the kidney sympathetic nervous system regulates the expression of LCN2 following ischemic stroke has not been identified.

METHODS

In this study, we established a middle cerebral artery occlusion (MCAO) model to induce ischemic stroke in mice. Renal function was assessed 24 h after cerebral ischemia-reperfusion injury. Transcriptomic sequencing of kidney tissue was performed to identify potential pathological mechanisms. The role of LCN2 in post-stroke renal injury was investigated using renal tubule-specific LCN2 knockout mice and a combination of qPCR, western blotting, immunofluorescence, and transmission electron microscopy. In addition, renal denervation (RDN) was used to explore the relationship between sympathetic nerves and the expression of renal LCN2.

RESULTS

Ischemic stroke significantly exhibits renal functional impairment 24 h after reperfusion. Notably, RNA sequencing and Western blotting revealed a markedly increased expression of renal LCN2 following ischemic stroke. Renal tubular Lcn2-specific knockout significantly ameliorated the occurrence of kidney function abnormalities after stroke. Subsequently, we observed that the activation of renal sympathetic nerves upregulates LCN2 and induces kidney function abnormalities after stroke.

CONCLUSIONS

These findings reveal a neural pathway in which the sympathetic nervous system upregulates LCN2, providing potential therapeutic strategies for renal protection following ischemic stroke.

Why should lymphocytes immune profile matter in sepsis?

The global incidence of critical illness has been steadily increasing, resulting in higher mortality rates thereby presenting substantial challenges for clinical management. Among these conditions, sepsis stands out as the leading cause of critical illness, underscoring the urgent need for continued research to enhance patient care and deepen our understanding of its complex pathophysiology. Lymphocytes play a pivotal role in both innate and adaptive immune responses, acting as key regulators of the balance between pro-inflammatory and anti-inflammatory processes to preserve immune homeostasis. In the context of sepsis, an impaired immunity has been associated with disrupted lymphocytic metabolic activity, persistent pro-inflammatory state, and subsequent immunosuppression. These disruptions not only impair pathogen clearance but also predispose patients to secondary infections and hinder recovery, highlighting the importance of targeting lymphocyte dysfunction in sepsis management. Moreover, studies have identified absolute lymphocyte counts and derived parameters as promising clinical biomarkers for prognostic assessment and therapeutic decision-making. In particular, neutrophil-to-lymphocyte ratio, and lymphopenia have gained recognition in the literature as a critical prognostic markers and therapeutic target in the management of sepsis. This review aims to elucidate the multifaceted role of lymphocytes in pathophysiology, with a focus on recent advancements in their use as biomarkers and key findings in this evolving field.

Venous excess ultrasound: A mini-review and practical guide for its application in critically ill patients

Advancements in healthcare technology have improved mortality rates and extended lifespans, resulting in a population with multiple comorbidities that complicate patient care. Traditional assessments often fall short, underscoring the need for integrated care strategies. Among these, fluid management is particularly challenging due to the difficulty in directly assessing volume status especially in critically ill patients who frequently have peripheral oedema. Effective fluid management is essential for optimal tissue oxygen delivery, which is crucial for cellular metabolism. Oxygen transport is dependent on arterial oxygen levels, haemoglobin concentration, and cardiac output, with the latter influenced by preload, afterload, and cardiac contractility. A delicate balance of these factors ensures that the cardiovascular system can respond adequately to varying physiological demands, thereby safeguarding tissue oxygenation and overall organ function during states of stress or illness. The Venous Excess Ultrasound (VExUS) Grading System is instrumental in evaluating fluid intolerance, providing detailed insights into venous congestion and fluid status. It was originally developed to assess the risk of acute kidney injury in postoperative cardiac patients, but its versatility has enabled broader applications in nephrology and critical care settings. This mini review explores VExUS’s application and its impact on fluid management and patient outcomes in critically ill patients.

Advancing extracorporeal carbon dioxide removal technology: bridging basic science and clinical practice

Recently, advancements in extracorporeal carbon dioxide removal (ECCO 2 R) technology have markedly enhanced its clinical applicability and efficacy for managing severe respiratory conditions. This review highlights critical innovations in ECCO 2 R, such as advanced catheter technologies, active mixing methods, and biochemical enhancements, which have substantially improved gas exchange efficiency and broadened the scope of ECCO 2 R applications. Integrating ECCO 2 R into acute and chronic respiratory care has led to a shift toward more mobile and less invasive modalities, promising for extending ECCO 2 R usage from intensive care units to home settings. By examining these technological advancements and their clinical impacts, this paper outlines the potential future directions of ECCO 2 R technology, emphasizing its role in transforming respiratory care practices and enhancing patient outcomes.

Where are we now? Biased signalling of Class B G protein-coupled receptor-targeted therapeutics

Class B G protein-coupled receptors (GPCRs) are a subfamily of 15 peptide hormone receptors with diverse roles in physiological functions and disease pathogenesis. Over the past decade, several novel therapeutics targeting these receptors have been approved for conditions like migraine, diabetes, and obesity, many of which are ground-breaking and first-in-class. Most of these therapeutics are agonist analogues with modified endogenous peptide sequences to enhance receptor activation or stability. Several small molecule and monoclonal antibody antagonists have also been approved or are in late-stage development. Differences in the sequence and structure of these therapeutic ligands lead to distinct signalling profiles, including biased behaviour or inhibition of specific pathways. Understanding this biased pharmacology offers unique development opportunities for improving therapeutic efficacy and reducing adverse effects. This review summarises current knowledge on the ligand bias of approved class B GPCR drugs, highlights strategies to refine and exploit their pharmacological profiles, and discusses key considerations related to receptor structure, localisation, and regulation for developing new therapies.

Effect of the aspect ratio and wall heterogeneities on the mechanical behaviour of the aneurysm wall: Experimental investigation on phantom arteries

The management of unruptured intracranial aneurysms (UIA) involves assessing the risk of rupture, which requires a thorough understanding of risk factors such as the geometric characteristics of the neck (neck size) or local structural heterogeneities. This study explores the impact of neck size on the rupture risk of the aneurysmal sac and examines how local heterogeneities, such as calcifications or variations in tissue composition, influence the mechanical response of the wall of a saccular aneurysm during the insertion of an innovative arterial wall deformation device (DDP). The results reveal that high aspect ratios (AR) are associated with increased hemodynamic stress, thereby raising the risk of rupture. Additionally, this study provides valuable insights into the complex relationship between tissue heterogeneity, especially calcifications, and the mechanical response of aneurysm walls to mechanical stimuli. It appears that local heterogeneities weaken the integrity of the arterial wall, thus increasing the potential for rupture. Finally, although the DDP is not intended to treat intracranial aneurysms (IA), it could prove to be a relevant tool for deepening the understanding of their rupture mechanisms.

Xenon gas as a potential treatment for opioid use disorder, alcohol use disorder, and related disorders

Xenon gas is considered to be a safe anesthetic and imaging agent. Research on its other potentially beneficial effects suggests that xenon may have broad efficacy for treating health disorders. A number of reviews on xenon applications have been published, but none have focused on substance use disorders. Accordingly, we review xenon effects and targets relevant to the treatment of substance use disorders, with a focus on opioid use disorder and alcohol use disorder. We report that xenon inhaled at subsedative concentrations inhibits conditioned memory reconsolidation and opioid withdrawal symptoms. We review work by others reporting on the antidepressant, anxiolytic, and analgesic properties of xenon, which could diminish negative affective states and pain. We discuss research supporting the possibility that xenon could prevent analgesic- or stress-induced opioid tolerance and, by so doing could reduce the risk of developing opioid use disorder. The rapid kinetics, favorable safety and side effect profiles, and multitargeting capability of xenon suggest that it could be used as an ambulatory on-demand treatment to rapidly attenuate maladaptive memory, physical and affective withdrawal symptoms, and pain drivers of substance use disorders when they occur. Xenon may also have human immunodeficiency virus and oncology applications because its effects relevant to substance use disorders could be exploited to target human immunodeficiency virus reservoirs, human immunodeficiency virus protein-induced abnormalities, and cancers. Although xenon is expensive, low concentrations exert beneficial effects, and gas separation, recovery, and recycling advancements will lower xenon costs, increasing the economic feasibility of its therapeutic use. More research is needed to better understand the remarkable repertoire of effects of xenon and its potential therapeutic applications.

Levosimendan improves central haemodynamic status and gas exchange in a model of ischaemic cardiac arrest: A large animal study

BACKGROUND

Ischaemic cardiac arrest has poor survival. In an earlier animal study, we have shown that levosimendan increases the return of spontaneous circulation and survival compared with placebo. However, the impact of levosimendan on central cardiovascular variables and gas exchange during resuscitation in ischaemic cardiac arrest is unknown.

OBJECTIVE

To evaluate levosimendan's dose-response effect on central cardiovascular variables and gas exchange in an established swine cardiac arrest model.

DESIGN

A large animal study.

SETTING

Animal study with Swedish landrace pigs at Karolinska Institutet, Sweden.

INTERVENTION

Ten swine underwent induced acute myocardial infarction and ventricular fibrillation. Levosimendan (62.5 μg kg -1 ) was administered during resuscitation, and immediate outcomes were compared with low dose levosimendan (12 μg kg -1 , n   =  12) or placebo ( n   =  12) from earlier experiments using the same model.

MAIN OUTCOME MEASURES

Haemodynamic and gas exchange variables during resuscitation. Time to and proportion of return to spontaneous circulation.

RESULTS

High-dose levosimendan improved gas exchange, with better arterial O 2 and CO 2 levels ( P  < 0.01), reduced systolic pulmonary arterial pressure, central venous pressure and vasopressor support with adrenaline after return to spontaneous circulation compared with low dose and placebo ( P  = 0.01). All animals in both levosimendan groups achieved return to spontaneous circulation compared with 67% in the placebo group ( P  = 0.02). Median [IQR] time to return of spontaneous circulation was 15 min [12 to 18] for high dose 17 min [15 to 26] for low dose compared with 23 min [15 to 60] for placebo ( P  = 0.08).

CONCLUSIONS

Levosimendan enhances key resuscitation outcomes in the immediate period of ischaemic cardiac arrest, promoting its potential as an effective pharmacological intervention. With an apparent dose-dependent reduction in right ventricular afterload and subsequent improvement in gas exchange, we cautiously propose that levosimendan-induced pulmonary vasodilation alleviates right heart strain and improves interventricular dependency, thereby enhancing the likelihood of return of spontaneous circulation.

Pre-clinical evidence for mitochondria as a therapeutic target for luteolin: A mechanistic view

Pre-clinical evidence indicates that mitochondria may be a therapeutic target for luteolin (3',4',5,7-tetrahydroxyflavone; LUT) in different conditions. LUT modulates mitochondrial physiology in in vitro, ex vivo, and in vivo experimental models. This flavone exerted mitochondria-related antioxidant and anti-apoptotic effects, stimulated mitochondrial fusion and fission, induced mitophagy, and promoted mitochondrial biogenesis in human and animal cells and tissues. Moreover, LUT modulated the activity of components of the oxidative phosphorylation (OXPHOS) system, improving the ability of mitochondria to produce adenosine triphosphate (ATP) in certain circumstances. The mechanism of action by which LUT promoted mitochondrial benefits and protection are not completely clear yet. Nonetheless, LUT is a potential candidate to be utilized in mitochondrial therapy in the future. In this work, it is explored the mechanisms of action by which LUT modulates mitochondrial physiology in different pre-clinical experimental models.

Cecal slurry-induced sepsis in mice impairs cognition and decreases SUMO-2/3 conjugation

Sepsis is characterized by multiple organ dysfunction, dysregulation of the response to the infection process, and a high mortality rate in intensive care units. In addition, individuals who overcome sepsis often manifest cognitive deficits associated with neuroinflammation resulting from the entry of pro-inflammatory cytokines into the brain. Post-translational protein modifications, such as SUMOylation, can regulate the expression of pro-inflammatory genes during sepsis. Since SUMO-2/3 can play a role in pathological conditions, our aim was to investigate a potential link between sepsis-induced cognitive decline and SUMOylation by this isoform. Firstly, the cecal slurry model was induced by intraperitoneally injecting male Swiss mice with different volumes of a cecal solution. Following assessment of body temperature, mass and septic scores, the groups that received 300 μL and 350 μL of the cecal solution were selected for the behavioural tests, as they presented signs of sepsis without excessive mortality. Surviving animals were evaluated for cognition/memory and anxious/depressive-like behaviours through the open-field, object recognition, Y-maze, and tail suspension tests. Subsequently, SUMO-2/3 conjugation was determined in samples from the hippocampus and prefrontal cortex by Western blotting. Mice in the septic groups showed decreased locomotor activity, anxious-and depressive-like behaviours, as well as impaired memory. These deficits were accompanied by a decrease in SUMO-2/3 conjugation in the hippocampus and prefrontal cortex at 24 h and 10 days after the induction of the cecal slurry model. Taken together, our findings suggest that SUMOylation is impaired in septic animals and this could be related to the behavioural deficits seen in the surviving mice.

Ozone controls the metabolism of tryptophan protecting against sepsis-induced intestinal damage by activating aryl hydrocarbon receptor

BACKGROUND

Intestinal injury is the most common complication of sepsis, and the mitigation of intestinal damage is crucial for treating sepsis.

AIM

To examine the use of ozone-rich water and its action in preventing intestinal damage caused by sepsis.

METHODS

Through histological analysis, immunohistochemistry, immunofluorescence assays, and Western blot detection, we evaluated the therapeutic efficacy of ozone in mitigating intestinal injury during sepsis. Additionally, by conducting 16S rRNA sequencing and untargeted metabolomics analysis on fecal samples, we identified alterations in the gut microbiota and specific metabolites in septic mice following ozone treatment. This comprehensive approach aims to further elucidate the mechanistic underpinnings of ozone therapy in alleviating sepsis-induced intestinal damage.

RESULTS

Our results demonstrate that ozonated water significantly ameliorates pathological damage in intestinal tissues, enhances the expression of tight junction proteins, and inhibits the polarization of intestinal macrophages, thereby reducing the expression of inflammatory cytokines in intestinal tissues of cecal ligation and puncture-induced septic mice. 16S rRNA sequencing analysis revealed that ozonated water increased the abundance of beneficial bacteria and alleviated gut microbiota dysbiosis. Studies using broad-spectrum antibiotic-treated mice indicated that the protective effects of ozonated water on intestinal injury are dependent on the gut microbiota. Furthermore, metabolomic analysis identified an increase in the tryptophan metabolite DL-tryptophan in the ozonated water treatment group. This suggests that ozonated water protects against intestinal injury by activating the aryl hydrocarbon receptor and suppressing necroptosis in intestinal epithelial cells.

CONCLUSION

Ozone protected against sepsis-induced intestinal injury through regulation of the gut microbiota and tryptophan metabolism, inhibiting necrotic apoptosis of intestinal epithelial cells through activation of the aryl hydrocarbon receptor.

Hyperglycemia in the diabetic range, but not previous diagnosis of diabetes mellitus, is an independent indicator of poor outcome in patients hospitalized for severe COVID-19

AIMS

Diabetes mellitus (DM) and hyperglycemia are associated with poor outcome(s) in COVID-19 hospitalized patients, but their independent impact on prognosis remains unclear. We aimed to assess the impact of DM and hyperglycemia on COVID-19 outcomes.

METHODS

Clinical data/records from COVID-19 patients admitted to the Parma University-Hospital (February 23rd to March 31st, 2020) were retrieved and analysed (NCT04550403). Fasting plasma glucose (FPG), inflammatory markers and the main biochemical variables were collected at admission. Patients underwent chest high-resolution CT and arterial blood gas analysis to determine the PaO2/FiO2 ratio (P/F ratio). The primary outcome was a composite of intensive care unit admission and/or death.

RESULTS

Among 756 subjects, 143 (19%) had DM. These patients were older with higher comorbidity rates. The primary outcome occurred in 61.5% DM patients versus 43.4% without DM (p < 0.001). In multivariable analysis (accuracy UC = 0.93), older age, cardiovascular and kidney diseases, FPG ≥ 126 mg/dl, C-reactive protein, and P/F ratio, but not previous DM, were independent risk indicators.

CONCLUSIONS

DM indicated poor COVID-19 outcomes, but not when adjusted for other clinical variables/comorbities, suggesting that its impact was mostly driven by concomitant factors. The independent role of fasting hyperglycemia points to the need for further research on its contribution to COVID-19.

SIGH35 and end-expiratory occlusion test for assessing fluid responsiveness in critically ill patients undergoing pressure support ventilation

BACKGROUND

Assessing fluid responsiveness is problematic for critically ill patients with spontaneous breathing activity, such as during Pressure Support Ventilation (PSV), since spontaneous breathing activity physiologically affects heart-lung interplay. We compared the reliability of two hemodynamic tests in predicting fluid responsiveness in this clinical setting: SIGH35, based on a ventilator-generated sigh applied at 35 cmH2O for 4 s and the end-expiratory occlusion test (EEOT).

METHODS

Prospective study conducted in a general intensive care unit (ICU) and enrolling patients in PSV showing different inspiratory effort [assessed by airway occlusion pressure (P0.1)] and requiring volume expansion (VE). Hemodynamic variables were recorded by means of the MOSTCARE® system, patient received a VE using 4 ml/kg of crystalloids over 10 min and were considered responders if a cardiac output (CO) ≥ 10% was observed. The reliability of SIGH35 and EEOT in discriminating fluid responsiveness was assessed using receiver operating characteristic (ROC) curve approach and the area (AUC) under ROC curves was compared. For the EEOT, we considered the percent changes of CO between baseline the end of the test, while for the SIGH35, the percent changes of pulse pressure (PP) between baseline and the lowest value recorded after SIGH35 application.

RESULTS

Sixty ICU patients were enrolled, and 56 patients analysed. The AUC of PP changes after SIGH35 was 0.93 (0.84-0.99) [sensitivity of 93.1% (78.0-98.7%); specificity of 91.6 (73.0-98.9%)]; best threshold - 25% PP from baseline (grey zone - 15%/35%)]; and greater than the AUC of CO changes after EEOT [0.67 (0.52-0.81); sensitivity of 72.4% (54.3-85.3%) specificity of 70.3% (73.0-98.9%)]; best threshold 4% of CO increase from baseline (grey zone - 1%/10%)]. In the subgroup having a P0.1 < 1.5 cmH2O, the AUC of SIGH35 [0.98 (0.94-0.99)] and of EEOT [0.89 (0.72-0.99] were comparable (p = 0.26).

CONCLUSIONS

In a selected ICU population undergoing PSV, SGH35 reliably predicted fluid responsiveness and performed better than the EEOT, which is, however, still reliable in the subgroup of ICU patients having a small extent of inspiratory efforts.

The effect of repeated maternal voice orientation on postoperative emergence agitation in children following tonsillectomy and adenoidectomy: A randomized controlled trial

STUDY OBJECTIVE

Evaluate the efficacy of repeated maternal voice orientation in reducing the incidence of emergence agitation (EA) in pediatric patients undergoing elective tonsillectomy and adenoidectomy.

DESIGN

Randomized controlled trial.

SETTING

A tertiary hospital.

PATIENTS

360 children aged 5-12 years undergoing elective tonsillectomy and adenoidectomy.

INTERVENTIONS

Patients were randomized into three groups: maternal voice orientation group (Group O), maternal voice awakening group (Group A), and a control group (Group C) receiving silent recordings.

MEASUREMENTS

The primary outcome was the incidence of EA, defined by a Pediatric Anesthesia Emergence Delirium (PAED) score of 12 or higher. Secondary outcomes included the severity of EA (PAED score > 14), postoperative pain (assessed using FLACC and NRS scales), and recovery profiles in the Post-Anesthesia Care Unit (PACU).

MAIN RESULTS

Maternal voice orientation (Group O) significantly reduced the incidence of EA compared to the control group and Group A, especially notable in the 5-8 year subgroup. Group O showed the lowest PAED scores immediately post-extubation and at 10 min.

CONCLUSIONS

Repeated maternal voice orientation effectively reduces the incidence and severity of EA among pediatric patients, supporting its inclusion in pediatric anesthesia recovery protocols to improve postoperative outcomes.

Recent Advances in Immunotherapeutic and Vaccine-Based Approaches for the Treatment of Drug-Resistant Bacterial Infections

Antimicrobial resistance poses a grave threat to global public health. Although new antibiotics are urgently needed, most share resistance mechanisms with existing drugs, thereby necessitating the development of alternative antibacterial therapeutics. Various immunotherapeutic agents, including monoclonal antibodies, therapeutic vaccines, cellular therapies, and immunomodulators, have been developed and explored to treat drug-resistant bacterial infections. This review comprehensively summarizes recent advancements in immunotherapies and vaccine-based approaches as alternative strategies to combat drug-resistant bacterial infections. Our findings indicate that immunotherapy offers several advantages over traditional antibiotics, such as enhanced specificity, long-term effects, overcoming resistance mechanisms, broad applicability, potential for combination therapies, personalized medicine, and reduced toxicity. Also, formulation and delivery strategies, including nanoparticles, liposomes, cellular vehicles, and diverse administration routes, have been employed to improve the efficacy and targeting of these immunotherapeutic agents. In-depth evaluations of promising preclinical and clinical studies demonstrate their potential effectiveness against pathogens such as Pseudomonas aeruginosa, Escherichia coli, Mycobacterium tuberculosis, Streptococcus pneumoniae, methicillin-resistant Staphylococcus aureus, Acinetobacter baumannii, and Helicobacter pylori. These suggest that immunotherapy is a promising alternative to address the growing challenge of drug-resistant bacterial infections, potentially revolutionizing infection management strategies.

Association Between Postoperative Lymphocyte Count and the Occurrence of Infections After Pediatric Cardiac Surgery With Cardiopulmonary Bypass

OBJECTIVE

The objective of this study was to evaluate the association between the minimal count of lymphocyte (Ly_Min) after cardiac surgery with cardiopulmonary bypass and the occurrence of infections within the first 30 postoperative days (POD).

METHODS

From a local European Congenital Heart Surgeons Association (ECHSA) database, all cardiac surgeries with cardiopulmonary bypass in children under 18 years old between January 2014 and December 2021 were eligible. Infections occurring within 30 POD were prospectively recorded according to ECHSA definitions, and classified into sepsis, pneumonia, wound infection, mediastinitis or endocarditis. For each surgery, Ly_Min was collected during the first 2 POD and the optimal threshold for predicting infection was chosen using receiver operating characteristic curve analysis. Univariate and multivariate logistic regression analyses were performed to identify variables associated with the risk of infection.

RESULTS

Of 1428 surgeries conducted over the 8-year period, 111 (8%) were complicated by at least 1 infection, including pneumonia (n = 45), wound infection (n = 41), sepsis (n = 24), mediastinitis (n = 20) and endocarditis (n = 3). Mean Ly_Min in the first 2 POD was lower in the infected group compared with the noninfected group (1.32 ± 0.81 vs. 1.81 ± 1.05 × 10 9 /L, P  < 0.001). After adjusting for confounders, Ly_Min <1.105 × 10 9 /L within the first 1 POD was independently associated with an increased risk of postoperative infections (adjusted odds ratio = 1.75, 95% confidence interval: 1.10-2.79, P = 0.019).

CONCLUSIONS

In this large single-center cohort of pediatric cardiac surgeries, Ly_Min during the first 2 POD was associated with the development of infections within 30 days after cardiopulmonary bypass.

Artificial Intelligence for the Detection of Patient-Ventilator Asynchrony

Patient-ventilator asynchrony (PVA) is a challenge to invasive mechanical ventilation characterized by misalignment of ventilatory support and patient respiratory effort. PVA is highly prevalent and associated with adverse clinical outcomes, including increased work of breathing, oxygen consumption, and risk of barotrauma. Artificial intelligence (AI) is a potentially transformative solution offering capabilities for automated detection of PVA. This narrative review characterizes the landscape of AI models designed for PVA detection and quantification. A comprehensive literature search identified 13 studies, spanning diverse settings and patient populations. Machine learning (ML) techniques, derivation datasets, types of asynchronies detected, and performance metrics were assessed to provide a contemporary view of AI in this domain. We reviewed 166 articles published between 1989 and April 2024, of which 13 were included, encompassing 332 participants and analyzing >5.8 million breaths. Patient counts ranged between 8 and 107 and breath data ranged between 1,375 and 4.2 M. The reason for invasive mechanical ventilation use was given as ARDS in three articles, whereas the remainder had different invasive mechanical ventilation indications. Various ML methods as well as newer deep learning techniques were used to address PVA types. Sensitivity and specificity of 10 of the 13 models were >0.9, and 8 models reported accuracy of >0.9. AI models have significant potential to address PVA in invasive mechanical ventilation, displaying high accuracy across various populations and asynchrony types. This showcases their potential to accurately detect and quantify PVA. Future work should focus on model validation in diverse clinical settings and patient populations.

ARDS Weaning: The Impact of Abnormal Breathing Patterns Detected by Electric Tomography Impedance and Respiratory Mechanics Monitoring

Background: After the improvement of the initial phase of ARDS, when the patients begin spontaneous breathing and weaning from mechanical ventilation, some patients may present abnormal breathing patterns, whose evaluation of the repercussions were poorly studied. This study proposed to evaluate abnormal breathing patterns through the use of electrical impedance tomography (EIT), and clinical, respiratory mechanics, and ventilatory parameters according to the types of weaning from mechanical ventilation. Methods: This was a prospective cohort study of subjects with ARDS who were considered able to be weaned from mechanical ventilation in the clinical-surgical ICU. Weaning types were defined as simple, difficult, and prolonged weaning. EIT, ventilatory, lung mechanics, and clinical data were collected. Data were collected at baseline in a controlled ventilatory mode and, after neuromuscular blocker withdrawal, data were collected after 30 min, 2 h, and 24 h. EIT parameter analysis was performed for ventilation distribution in the lung regions, pendelluft, breath-stacking, reverse-trigger, double-trigger, and asynchrony index. Results: The study included 25 subjects who were divided into 3 groups (9/25 simple, 8/25 difficult, and 8/25 prolonged weaning). The prolonged weaning group showed more delirium, ICU-acquired weakness, stay in ICU, and hospital and ICU mortality. During the change from controlled to spontaneous mode, we observed increased tidal volumes and driving pressures, which were mainly found in the prolonged weaning group when compared with the simple weaning group. The prolonged weaning group showed a higher flow index, more asynchronies during volume-assisted ventilation, a higher incidence of pendelluft, and redistribution of ventilation to posterior regions visualized by EIT. Conclusions: The present study showed abnormal breathing patterns in the prolonged weaning group. The clinical occult findings of abnormal breathing patterns could be monitored, mainly through EIT and with better assessment of pulmonary mechanics.

Repurposing FDA-approved drugs as NLRP3 inhibitors against inflammatory diseases: machine learning and molecular simulation approaches

Activation of NLRP3 (NOD-like receptor family, pyrin domain-containing protein 3) has been associated with multiple chronic pathologies, including diabetes, atherosclerosis, and rheumatoid arthritis. Moreover, histone deacetylases (HDACs), specifically HDAC6 is required for the NLRP3 inflammasome to assemble and activate. Thus, NLRP3 serves as an attractive target for the development of novel therapeutic approaches. Several companies are now attempting to develop specific modulators of the NLRP3 inflammasome, but only a handful of small molecules of NLRP3 inflammasome inhibitors, such as MCC950 and Tranilast, are currently available for clinical use. However, their use is limited due to severe side effects and short half-lives. Thus, the repurposing of FDA-approved drugs with NLRP3 inhibitory activity is needed. The present study was aimed at repurposing preexisting drugs that might act as safe and effective NLRP3 inhibitors. A library of 2,697 FDA-approved drugs was screened for binding with NLRP3 (PDB: 7ALV) using Glide (Schrödinger). The top seven FDA-approved drugs with potential binding affinities were selected based on docking scores and subjected to ADMET profiling using pkCSM and SwissADME. The binding of the ADMET-favorable FDA-approved drugs to NLRP3 was validated using MMGBSA (Prime) and Molecular Dynamics (Desmond) in the Schrödinger suite. ADMET profiling revealed that of the seven best docking drugs, empagliflozin and citicoline had good drug-likeness properties. Moreover, MMGBSA analysis and molecular dynamics demonstrated that empagliflozin and citicoline exhibited stable ligand-NLRP3 interactions in the presence of solvents. This study sheds light on the ability of various FDA-approved drugs to act as NLRP3 inhibitors.

OPTIMAL PAO 2 IS 130-160 MMHG IN THE FIRST WEEK FOR SEPSIS PATIENTS IN ICU: A RETROSPECTIVE COHORT STUDY BASED ON MIMIC-IV DATABASE

ABSTRACT

Background: The relationship between the partial pressure of oxygen in arterial blood (PaO 2 ) and the prognosis of sepsis patients, and its potential variation over time, remains unclear. The optimal PaO 2 range for sepsis patients has always been a contentious issue, with no consensus. We aimed to explore the association between different levels of PaO 2 exposure over time and the 28-day mortality of sepsis patients, and to identify the optimal PaO 2 range for sepsis patients within a specific time frame. Methods: We retrieved data on adult patients diagnosed with sepsis within 24 h before or after intensive care unit (ICU) admission from the Medical Information Mart for Intensive Care IV (MIMIC-IV, version 2.2) database. We excluded patients who were not admitted to the ICU for the first time, those with ICU stay <24 h, and those without PaO 2 results during their ICU stay. We calculated the time-weighted average (TWA) of PaO 2 and used piece-wise exponential additive mixed models (PAMMs) to estimate the time-dependent changes in the association between TWA-PaO 2 and patient prognosis. Results: A total of 16,880 sepsis patients were included in the MIMIC cohort. Results indicated that patients' TWA-PaO 2 correlates with increased 28-day mortality after ICU admission in sepsis patients, and this association was mainly manifested in the early course of the disease. With a time window of the first 1-7 days after ICU admission, the optimal TWA-PaO 2 range for sepsis patients was ≥130 mmHg and ≤160 mmHg. Increased exposure time, proportion of exposure time, and exposure dose of high-risk PaO 2 outside the range were all associated with an increased risk of 28-day mortality. Conclusion: PaO 2 in sepsis patients should be closely monitored. During the first 1-7 days of ICU admission, PaO 2 should be maintained within the range of ≥130 mmHg and ≤160 mmHg. A dose-dependent relationship exists between high-risk PaO 2 outside the range and patient outcome.

Advances in pediatric sepsis biomarkers - what have we learnt so far?

INTRODUCTION

Sepsis is a systemic immune dysregulation syndrome triggered by secondary infection in the host, with diagnosis based on the updated Phoenix criteria and characterized by multi-organ failure as its core pathological manifestation. It is a significant global health challenge due to its increasing incidence and high mortality rates. Recent advancements in biomarker research provide promising tools for improving early diagnosis and timely intervention, essential for better patient outcomes.

AREAS COVERED

This review examines the latest developments in pediatric sepsis biomarkers, categorized by inflammation, metabolism, organ damage, and non-coding RNAs (miRNAs, LncRNAs). We discuss the advancements in each category, highlighting the integration of diverse biomarkers and advanced technologies to enhance diagnostics, personalize therapy, and improve patient stratification.

EXPERT OPINION

Given the limited specificity and sensitivity of current markers like CRP and PCT, multicenter studies are crucial for validating new biomarkers and for developing comprehensive panel markers that combine multiple diagnostic indicators. It is also important to consider the variability in host responses to different pathogens when identifying biomarkers based on host-pathogen interactions. To advance personalized medicine, future research may prioritize the identification of specific diagnostic biomarkers for pediatric sepsis, tailored to different pathogens.

Progression of serum creatinine and glomerular filtration rate in neonatal critical care patients during the first seven days of life

BACKGROUND

Serum creatinine and estimated glomerular filtration rate (GFR) are key indicators of kidney function.

METHODS

This descriptive, retrospective study included neonatal patients admitted to a tertiary hospital's neonatal intensive care unit from January 2013 to December 2016. Data on kidney function were collected from birth to 7 days of life. Patients were stratified into four gestational age groups: below 28 weeks, 28-31 weeks, 32-36 weeks, and term neonates. Qualitative variables were expressed as percentages. Quantitative variables were assessed using the Kruskal-Wallis/Wilcoxon tests. Chi-square analysis was performed for categorical variables. Statistical analysis was conducted using SPSS (Version 22.0), with significance set at p < 0.05.

RESULTS

Among 138 patients, 99 (71.7%) were premature. Term neonates showed a gradual postnatal decline in creatinine, while premature infants exhibited an initial rise followed by a decline, with values inversely proportional to gestational age (at seven days: 0.70 ± 0.19 mg/dL in below 28 weeks vs. 0.39 ± 0.08 mg/dL in term, p < 0.001). Among the clinical-epidemiological variables of the included patients, seven significantly influenced serum creatinine. GFR decreased in premature neonates at 24 h, then increased throughout the study. Term neonates demonstrated a progressive GFR increase, with higher values associated with greater gestational age (at seven days:16.8 ± 5.0 ml/min/1.73m2 in below 28 weeks vs. 41.8 ± 8.0 ml/min/1.73m2 in term, p < 0.001).

CONCLUSIONS

Evaluating kidney function in neonates, based on serum creatinine and GFR, requires special attention during the first days of life, particularly in critically ill neonates due to multiple physiological changes and clinical factors that may influence these parameters.

Exploring DMT: Endogenous role and therapeutic potential

N,N-Dimethyltryptamine (DMT) is a naturally occurring amine and psychedelic compound, found in plants, animals, and humans. While initial studies reported only trace amounts of DMT in mammalian brains, recent findings have identified alternative methylation pathways and DMT levels comparable to classical neurotransmitters in rodent brains, calling for a re-evaluation of its biological role and exploration of this inconsistency. This study evaluated DMT's biosynthetic pathways, focusing on indolethylamine N-methyltransferase (INMT) and its isoforms, and possible regulatory mechanisms, including alternative routes of synthesis and how physiological conditions, such as stress and hypoxia influence DMT levels. This review considers the impact of endogenous regulatory factors on DMT synthesis and degradation, particularly under conditions affecting monoamine oxidase (MAO) efficiency and activity. We also examined DMT's potential roles in various physiological processes, including neuroplasticity and neurogenesis, mitochondrial homeostasis, immunomodulation, and protection against hypoxia and oxidative stress. DMT's lipophilic properties allow it to cross cell membranes and activate intracellular 5-HT2A receptors, contributing to its role in neuroplasticity. This suggests DMT may act as an endogenous ligand for intracellular receptors, highlighting its broader biological significance beyond traditional receptor pathways. The widespread evolutionary presence of DMT's biosynthetic pathways across diverse species suggests it may play essential roles in various developmental stages and cellular adaptation to environmental challenges, highlighting the neurobiological significance of DMT and its potential clinical applications. We propose further research to explore the role of endogenous DMT, particularly as a potential neurotransmitter.

Evaluating the evidence for GM-CSF as a host-directed therapy in respiratory infections

Novel therapeutic approaches are needed to treat respiratory infections due to the rising antimicrobial resistance and the lack of effective antiviral therapies. A promising avenue to overcome treatment failure is to develop strategies that target the host immune response rather than the pathogen itself. Granulocyte-macrophage colony-stimulating factor (GM-CSF) plays a critical role in controlling homeostasis in lungs, alveolar macrophages being the most sensitive cells to GM-CSF signaling. In this review, we discuss the importance of GM-CSF secretion for lung homeostasis and its alteration during respiratory infections. We also present the pre-clinical evidence and clinical investigations evaluating GM-CSF-based treatments (administration or inhibition) as a therapeutic strategy for treating respiratory infections, highlighting both supporting and contradictory findings.

Cytokine Hemoadsorption versus Standard Care in Cardiac Surgery Using the Oxiris Membrane: The OXICARD Single-center Randomized Trial

BACKGROUND

Cardiac surgery can lead to dysregulation with a proinflammatory state, resulting in adverse outcomes. Hemadsorption using the AN-69 membrane (Oxiris membrane, Baxter, USA) has the properties to chelate inflammatory cytokines. The authors hypothesized that in patients at high risk of inflammation, the use of the Oxiris membrane could decrease inflammation, preserve endothelial function, and improve postoperative outcomes.

METHODS

The authors conducted a randomized single-center study at Amiens University Hospital (Amiens, France). The study population consisted of adult patients admitted for scheduled cardiac surgery with an expected cardiopulmonary bypass (CPB) time greater than 90 min. The patients were allocated to either the standard group or the Oxiris group. The intervention consisted of using the Oxiris membrane on a Prismaflex device (Baxter, USA) at a blood flow rate of 450 ml/min during CPB. The primary outcome was the assessment of microcirculation on day 1 after surgery by measuring sublingual microcirculation using the microvascular flow index. Microvascular flow index reflects the microcirculation flow type and is graded from 0 to 3 as follows: 0, no flow; 1, intermittent flow; 2, sluggish flow; 3, continuous flow. The secondary outcome was a composite adverse outcome within 30 days after surgery. Cytokines and endothelial biomarkers were measured in all patients at different time points. An intention-to-treat analysis was performed.

RESULTS

From October 2019 to November 2022, the study included 70 patients. Two patients were excluded from the Oxiris group: one patient did not undergo surgery, and one procedure was performed under deep hypothermia. The microvascular flow index did not differ between groups on day 1 from baseline: difference (95% CI) Oxiris minus standard at -0.17 (-0.44 to 0.10); P = 0.2. The occurrence of a composite adverse outcome did not significantly differ between groups (14 [42%] for the Oxiris group vs. 12 [35%] for the standard group; P = 0.7). The overall variation in cytokines and angiopoietins did not significantly differ between groups.

CONCLUSIONS

In patients scheduled for a cardiac surgery with prolonged CPB, the authors could not demonstrate the benefit on microcirculation and major cardiovascular events.

Intraoperative Oxygenation and Microcirculatory Changes Following Off-pump Coronary Artery Bypass Grafting: An Exploratory Secondary Analysis of a Randomized Clinical Trial

OBJECTIVES

The effect of perioperative hyperoxia on microcirculation after cardiac surgery remains inconclusive. We evaluated the relationship between intraoperative fractional inspired oxygen and microcirculation after off-pump coronary artery bypass grafting (OPCAB).

DESIGN

Exploratory secondary analysis of a multicenter cluster-randomized trial.

SETTING

Three teaching hospitals.

PARTICIPANTS

Adult patients who underwent OPCAB.

INTERVENTIONS

Seven postoperative microcirculatory parameters, including De Backer scores and the proportion of perfused vessels via sublingual microscopy (from all and small vessels), and thenar muscle tissue oxygenation, occlusion slope, and recovery slope via the vascular occlusion test, were compared between patients receiving 30% and 80% oxygen intraoperatively. Generalized estimating equations were used to account for intracluster correlation.

MEASUREMENTS AND MAIN RESULTS

The analysis included 52 and 51 patients from the 30% and 80% oxygen groups, respectively, for sublingual microscopy and 59 and 53 patients for the vascular occlusion test. Although all microcirculatory parameters were similar between groups, the 80% oxygen group had higher De Backer scores for all vessels (mean, 9.8 ± 2.9 mm-1 vs. 8.7 ± 2.0 mm-1; p = 0.011) and small vessels (4.0 ± 1.8 mm-1 vs. 3.4 ± 1.1 mm-1; p = 0.024) than the 30% oxygen group at the end of surgery. The 80% oxygen group also exhibited greater thenar muscle tissue oxygenation immediately before vascular occlusion (78.4% ± 10.5 vs. 74.0% ± 9.3; p = 0.031) and a higher recovery score (4.1%·s-1 ± 1.7 vs. 3.2%·s-1 ± 1.4; p = 0.001).

CONCLUSIONS

Patients receiving 80% oxygen during OPCAB had significantly better postoperative microcirculatory profiles than those receiving 30% oxygen. These findings highlight the potential for optimizing perioperative oxygenation to improve or mitigate microcirculatory impairment, thereby reducing postoperative complications.

Noninvasive Ventilation in Acute Asthma Exacerbations: A Systematic Review

Rationale: Because of a paucity of evidence, multiple clinical practice guidelines lack recommendations pertaining to noninvasive ventilation (NIV) in acute asthma exacerbations. However, the evidence syntheses for these guidelines were performed years ago, and more recent randomized controlled trials (RCTs) and observational studies have been published. Objectives: We sought to update the evidence syntheses from previous guidelines to further clarify the effects of NIV in acute asthma exacerbations. Methods: A systematic search of Medline, Embase, and the Cochrane Library was conducted, studies comparing NIV plus standard medical therapy with standard medical therapy alone in adults with acute asthma exacerbations were selected using a priori selection criteria, and relevant data were extracted. Weighted aggregation (meta-analysis) was performed to summarize effects, which were appraised using the Grading of Recommendations, Assessment, Development, and Evaluation (or, GRADE) approach. Results: Eight RCTs and five observational studies were selected. NIV was associated with a reduced intubation rate (RCTs: risk ratio [RR] = 0.46; 95% confidence interval [CI] = 0.16 to 1.29; observational studies: RR = 0.55; 95% CI = 0.45 to 0.68), admission rate (RR = 0.57; 95% CI = 0.34 to 0.98), and time to improvement in accessory muscle use (mean difference = -1.13 h; 95% CI = -1.28 to -0.99). Additional outcomes favored NIV plus standard medical therapy but did not reach statistical significance, including dyspnea measures and spirometry measures. There were too few deaths to assess mortality reliably. The quality of evidence ranged from low to very low for all outcomes. Conclusions: All statistically significant outcomes favored NIV plus standard medical therapy over standard medical therapy alone in adults with acute asthma exacerbations. Our aggregate data suggest that intubation rate may be reduced with NIV plus standard medical therapy, although the overall quality of the evidence is low. If this is a true effect, it may be clinically important, because intubation has been shown to correlate with mortality in multiple observational trials. Given these findings, patients with acute asthma exacerbations may benefit from a trial of NIV in addition to standard medical therapy.

Increasing heterogeneity is associated with IL-6 expression in the lungs following mechanical ventilation

This study aimed to characterize how peak inspiratory pressure (PIP) and positive end-expiratory pressure (PEEP) influence regional lung volume heterogeneity as a result of mechanical ventilation and the influence of this heterogeneity on markers of inflammation within the lungs. Four groups of BALB/C mice (n = 7 or 8 per group) were mechanically ventilated for 2 h using low or high (12 cmH2O or 20 cmH2O) peak inspiratory pressure (PIP) with or without 2 cmH2O positive end-expiratory pressure (PEEP). Four-dimensional computed tomography (4-DCT) images were acquired using synchrotron-based radiation source at baseline and after 2 h. Regional tidal volumes were obtained by 4-D cross-correlational X-ray velocimetry, whereas end-expiratory volume was quantified by Hounsfield units. Tissue was harvested from 10 lung regions, and expression of IL-6 and monocyte chemo-attractant protein 1 (MCP-1) was quantified using qPCR. We found a significant reduction in specific end-expiratory volume (sEEV) in mice ventilated with low PIP and no PEEP and a reduction in tidal volume in groups without PEEP. End-expiratory volume heterogeneity decreased in the low PIP and no PEEP group, whereas tidal volume heterogeneity decreased in the equivalent high PIP group, potentially due to regional redistribution of lung volumes. We found associations between IL-6 expression and tidal volume heterogeneity. In this study, we have demonstrated that changes in PIP and PEEP impact atelectasis, overdistension, and heterogeneity, and that increases in tidal volume heterogeneity may be driving IL-6-mediated biotrauma. These findings highlight the importance of considering the spatial distribution of tidal volumes as a driver of lung injury during mechanical ventilation.NEW & NOTEWORTHY The combination of low inspiratory and expiratory pressure promotes atelectasis but is not associated with markers of injury in the healthy lung during short-term ventilation. High inspiratory pressures promote tidal volume heterogeneity, which is correlated with the expression of genetic markers of lung injury. These data suggest that heterogeneity in tidal volume may be a key driver of biotrauma in the healthy, mechanically ventilated lung.

The context-dependent effect of cellular senescence: from embryogenesis and wound healing to aging

Aging is characterized by a steady loss of physiological integrity, leading to impaired function and increased vulnerability to death. Cell senescence is a biological process that progresses with aging and is believed to be a key driver of age-related diseases. Senescence, a hallmark of aging, also demonstrates its beneficial physiological aspects as an anti-cancer, pro-regenerative, homeostatic, and developmental mechanism. A transitory response in which the senescent cells are quickly formed and cleared may promote tissue regeneration and organismal fitness. At the same time, senescence-related secretory phenotypes associated with extended senescence can have devastating effects. The fact that the interaction between senescent cells and their surroundings is very context-dependent may also help to explain this seemingly opposing pleiotropic function. Further, mitochondrial dysfunction is an often-unappreciated hallmark of cellular senescence and figures prominently in multiple feedback loops that induce and maintain the senescent phenotype. This review summarizes the mechanism of cellular senescence and the significance of acute senescence. We concisely introduced the context-dependent role of senescent cells and SASP, aspects of mitochondrial biology altered in the senescent cells, and their impact on the senescent phenotype. Finally, we conclude with recent therapeutic advancements targeting cellular senescence, focusing on acute injuries and age-associated diseases. Collectively, these insights provide a future roadmap for the role of senescence in organismal fitness and life span extension.

Development and validation of an algorithm for identifying patients undergoing dialysis from patients with advanced chronic kidney disease

BACKGROUND

Identifying patients on dialysis among those with an estimated glomerular filtration rate (eGFR) < 15 mL/min/1.73 m2 remains challenging. To facilitate clinical research in advanced chronic kidney disease (CKD) using electronic health records, we aimed to develop algorithms to identify dialysis patients using laboratory data obtained in routine practice.

METHODS

We collected clinical data of patients with an eGFR < 15 mL/min/1.73 m2 from six clinical research core hospitals across Japan: four hospitals for the derivation cohort and two for the validation cohort. The candidate factors for the classification models were identified using logistic regression with stepwise backward selection. To ensure transplant patients were not included in the non-dialysis population, we excluded individuals with the disease code Z94.0.

RESULTS

We collected data from 1142 patients, with 640 (56%) currently undergoing hemodialysis or peritoneal dialysis (PD), including 426 of 763 patients in the derivation cohort and 214 of 379 patients in the validation cohort. The prescription of PD solutions perfectly identified patients undergoing dialysis. After excluding patients prescribed PD solutions, seven laboratory parameters were included in the algorithm. The areas under the receiver operation characteristic curve were 0.95 and 0.98 and the positive and negative predictive values were 90.9% and 91.4% in the derivation cohort and 96.2% and 94.6% in the validation cohort, respectively. The calibrations were almost linear.

CONCLUSIONS

We identified patients on dialysis among those with an eGFR < 15 ml/min/1.73 m2. This study paves the way for database research in nephrology, especially for patients with non-dialysis-dependent advanced CKD.

Fluoxetine mitigates hypothermia and inflammatory responses in lipopolysaccharide-induced systemic inflammation: Insights into serotonergic and hypothalamic thermoregulatory mechanisms

An abnormally elevated mortality rate is evident in cases of sepsis. To study specific mechanisms of sepsis experimentally, lipopolysaccharide (LPS) systemically administered has been used as a model, in which an exaggerated immune response, neurochemistry settings, and fever following hypothermia take place. Notably, systemic inflammation (SI) can modulate the central serotonergic pathways and being influenced by it. This influence extends to the hypothalamus, which holds a hierarchical significance in the control of body temperature (Tb). This study investigates the potential impact of orally administered fluoxetine (FLX), a selective serotonin reuptake inhibitor (SSRI) given orally for 7 days before on LPS-induced SI (1.5 mg/kg, i.v.) in rats. The assessment involved monitoring Tb, heat loss index (HLI), along non-shivering thermogenesis assessed by oxygen consumption. Cytokine levels in the spleen and blood, along with nitric oxide (NO), and prostaglandins (PGs) E2 and D2, levels were also measured. The findings reveal increased plasma NO, cytokines in plasma and spleen, and hypothalamus PGE2 levels during SI. Interestingly, FLX mitigated LPS-induced hypothermia, accompanied by a reduction in plasma and splenic NO, interleukins (IL) 6, and 10. Additionally, the results align with the hypothesis that hypothermia, blunted by FLX, develops in fact in a regulated form, as an adaptive strategy.

Insights into the Role of the Glymphatic System in the Pathogenesis of Post-hemorrhagic Hydrocephalus

Recently, it has been well-established that the glymphatic or glial-lymphatic system plays a vital role in the pathophysiology of various neurological compromise, especially hydrocephalus (HCP). Till now, the complete pathway is not yet fully understood, and little evidence is available from the literature that links hydrocephalus to disorders of the glymphatic system. Most published molecular studies and animal research have shown that, in models with hydrocephalus, the drainage of cerebrospinal fluid (CSF) via the glymphatic system is disrupted. This is strongly observed in normal pressure and post-hemorrhagic hydrocephalus cases. A thorough search of the literature to date yields scarce evidence on studies conducted on humans. Despite major similarities between non-human and human glymphatic pathways, the need for studies conducted on humans is becoming more urgent as the glymphatic pathway has been shown to be a good candidate for therapeutic intervention. In this review, we collect and report the most updated evidence addressing the glymphatic drainage pathways and their associations with the development of various types of hydrocephalus. In addition, we reveal the current scientific gap in human studies and our recommendations for the conduction of future clinical studies.

Adaptations in mitochondrial quality control and interactions with innate immune signaling within skeletal muscle: A narrative review

Skeletal muscle health and function are essential determinants of metabolic health, physical performance, and overall quality of life. The quality of skeletal muscle is heavily dependent on the complex mitochondrial reticulum that contributes toward its unique adaptability. It is now recognized that mitochondrial perturbations can activate various innate immune pathways, such as the nucleotide-binding oligomerization domain (NOD)-like receptor protein 3 (NLRP3) inflammasome complex by propagating inflammatory signaling in response to damage-associated molecular patterns (DAMPs). The NLRP3 inflammasome is a multimeric protein complex and is a prominent regulator of innate immunity and cell death by mediating the activation of caspase-1, pro-inflammatory cytokines interleukin-1β and interleukin-18 and pro-pyroptotic protein gasdermin-D. While several studies have begun to demonstrate the relationship between various mitochondrial DAMPs (mtDAMPs) and NLRP3 inflammasome activation, the influence of various metabolic states on the production of these DAMPs and subsequent inflammatory profile remains poorly understood. This narrative review aimed to address this by highlighting the effects of skeletal muscle use and disuse on mitochondrial quality mechanisms including mitochondrial biogenesis, fusion, fission and mitophagy. Secondly, this review summarized the impact of alterations in mitochondrial quality control mechanisms following muscle denervation, aging, and exercise training in relation to NLRP3 inflammasome activation. By consolidating the current body of literature, this work aimed to further the understanding of innate immune signaling within skeletal muscle, which can highlight areas for future research and therapeutic strategies to regulate NLRP3 inflammasome activation during divergent metabolic conditions.

Impact of antiplatelet therapy on outcomes of sepsis: A systematic review and meta-analysis

OBJECTIVE

Antiplatelet therapy has been studied for its potential benefits in various cardiovascular conditions, but its role in sepsis remains less clear. This review aims to systematically analyse the available evidence on the effects of antiplatelet therapy in sepsis to assess its potential benefits and risks.

MATERIAL AND METHODS

The studies published until 01st April 2024 from PubMed, Embase and Scopus databases were searched. Pooled effect sizes were reported as relative risks (RR) or weighted mean difference (WMD) with corresponding 95% confidence intervals (CI). Outcomes included mortality, length of intensive care unit (ICU) stay, hospital stay, and the risk of complications. The certainty of evidence was evaluated using GRADE.

RESULTS

Twenty-one studies were included. Antiplatelet therapy was associated with significantly lower risk of in-hospital mortality (RR 0.76, 95% CI: 0.67, 0.87), and mortality at one (RR 0.77, 95% CI: 0.66, 0.90) and three months (RR 0.77, 95% CI: 0.66, 0.90) follow up. Risk of complications was comparable in all patients (RR 1.01, 95% CI: 0.84, 1.21). ICU stay (in days) (WMD -0.23, 95% CI: -0.53, 0.07; N=7, I2=97.2%) and overall duration of hospital stay (in days) (WMD 0.63, 95% CI: -0.66, 1.92; N=6, I2=93.2%) was also statistically similar among patients who received and did not receive antiplatelet drugs. The certainty of evidence for the outcomes ranged from "low to very low".

CONCLUSION

Antiplatelet therapy appears safe and significantly lowers the risk of short-term mortality in septic patients. While antiplatelet therapy did not impact the duration of ICU or overall hospital stay, our findings underscore the potential of antiplatelet agents as a beneficial adjunctive therapy in sepsis management.

Suspected sepsis: patient assessment and management in the emergency department

Sepsis is a potentially life-threatening condition triggered by infection that is responsible for an estimated 48,000 deaths in the UK each year. Its pathophysiology is complex, its symptomology non-specific and its clinical presentations extremely varied. Despite numerous campaigns to raise awareness of sepsis, it still goes undetected. In 2024, the National Institute for Health and Clinical Excellence revised its guideline on sepsis and the UK Sepsis Trust published the seventh edition of its Sepsis Manual. This article discusses the pathophysiology of sepsis and how emergency nurses should assess and manage patients with suspected sepsis. It describes the tools available to them, including the National Early Warning Score 2 and the Sepsis 6, and emphasises the importance of early antibiotic administration, serial lactate measurements, source control and antimicrobial stewardship.

Frailty and Long-Term Survival in Patients With Critical Illness After Nonhome Discharge: A Retrospective Cohort Study

IMPORTANCE

Patients with frailty are more frequently discharged to rehabilitation or residential aged care facility (RACF), defined as nonhome discharge, than those without frailty. An increase in nonhome discharge is considered to be one of the collateral "costs" associated with declining hospital mortality. However, it is unclear whether this association applies to patients with frailty, particularly in the long term.

OBJECTIVES

To determine the impact of frailty on long-term survival in patients who had a nonhome discharge following an ICU admission.

DESIGN

A retrospective multicenter cohort study.

SETTING AND PARTICIPANTS

All medical patients (≥ 16 yr old) admitted to Australian and Zealand ICUs, with a documented Clinical Frailty Scale (CFS) and a nonhome discharge from January 1, 2018, to March 31, 2022, were included.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Primary outcome was survival time up to 4 years. We used Cox proportional hazards regression models with robust sandwich variance estimators to assess the effect of frailty (defined as CFS = 5-8) on survival time after ICU admission between groups. We also analyzed the effect of frailty on long-term survival based on their age and nonhome discharge location. Of the 57,652 patients, 17,383 (30.2%) were frail. Overall 4-year survival was lower in patients with frailty than those without (32.5% vs. 64.3%; p < 0.001). Frailty was associated with shorter survival times (adjusted hazard ratio [aHR], 1.50; 95% CI, 1.43-1.57). Frailty was associated with a greater reduction in survival in patients younger than 65 years old (aHR, 1.73; 95% CI, 1.59-1.88), 65-80 years (aHR, 1.47; 95% CI, 1.38-1.57), or older than 80 years (aHR, 1.35; 95% CI, 1.26-1.45). Frailty was associated with greater reduction in survival in those discharged to rehabilitation (aHR, 1.52; 95% CI, 1.39-1.65) or acute hospitals (aHR, 1.56; 95% CI, 1.48-1.65) than those discharged to RACF (aHR, 0.94; 95% CI, 0.83-1.06).

CONCLUSIONS

Frailty was independently associated with shorter time to death following a nonhome discharge after an ICU admission.

RELEVANCE

There was an independent association between patients with frailty admitted to ICU and had a nonhome discharge with the shorter time to death than those without frailty.

Elevated Serum SERPINE2 Levels are Linked to Impaired Renal Function in Patients with Type 2 Diabetes Mellitus

INTRODUCTION

Diabetic nephropathy (DN) is the primary complication associated with diabetes mellitus and is increasingly acknowledged as the leading cause of end-stage renal disease worldwide, placing a significant economic burden on society. This study determined how blood serpin peptidase inhibitor clade E member 2 (SERPINE2) levels affect DN in individuals with type 2 diabetes mellitus (T2DM).

METHODS

We recruited 292 individuals diagnosed with T2DM and 120 healthy controls for this study. We employed comprehensive and systematic data collection methodologies to gather relevant biomarkers and information on biochemical parameters. We measured serum levels of neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule 1 (KIM-1), transforming growth factor-β1 (TGFβ1), connective tissue growth factor (CTGF), and SERPINE2 by the enzyme-linked immunosorbent assay in control subjects and patients with T2DM. We calculated generalized odds ratios (OR) to estimate the risk of developing DN.

RESULTS

Patients with diabetes had significantly higher levels of SERPINE2 (285.64 ± 56.58 pg/mL) than healthy controls (184.84 ± 23.54 pg/mL). Additionally, the multivariate logistic regression analysis indicated that patients with diabetes with DN possessed higher levels of serum SERPINE2 (OR 1.033, 95% confidence interval [CI] 1.013-1.053; P = 0.001), along with an increased body mass index (BMI), duration of diabetes, serum creatinine (Scr), NGAL, KIM-1, TGFβ1, and CTGF. Receiver operating characteristic (ROC) curve analysis indicated that patients with T2DM and serum SERPINE2 levels exceeding 278.94 pg/mL had a significantly higher risk of developing DN.

CONCLUSION

The results showed that patients with diabetes with DN have higher levels of serum SERPINE2. A more extensive population-based prospective study is needed to validate our findings.

Prone positioning during veno-venous extracorporeal membrane oxygenation: a systematic review and meta-analysis

PURPOSE

The evidence supporting the benefit on clinical outcomes of prone positioning during veno-venous extracorporeal membrane oxygenation (V-V ECMO) for acute hypoxemic respiratory failure remains inconclusive. We aimed to assess the association of prone positioning, compared to no prone positioning, with 28-day mortality and other clinical outcomes in different patient subgroups.

METHODS

A systematic review and meta-analysis of randomized and non-randomized controlled trials (RCTs) using a random-effects model was conducted. An electronic database search up to September 1st, 2024 was performed (PROSPERO CRD42024517602). The RoB 2 and ROBINS-I tools were used for risk of bias assessments.

RESULTS

We analyzed two RCTs and 20 non-RCTs (3,465 patients). Compared to no prone positioning, the use of prone positioning was associated with lower 28-day (odds ratio [OR] 0.64, 95% confidence interval [CI] 0.42-0.98, p = 0.040, I2 = 66%, low certainty of evidence [CoE]) and hospital mortality (OR 0.67, 95% CI 0.54-0.83, p < 0.001, I2 = 39%, low CoE), despite fewer 28-day ventilator-free days and longer ECMO duration. Younger age (p = 0.005), a higher sequential organ failure assessment (SOFA) score (p = 0.022), non-Covid-19 etiology (p = 0.003), and lower rates of prone positioning before cannulation (p = 0.049) were associated with a greater benefit from prone positioning.

CONCLUSION

In this analysis, among patients supported with V-V ECMO for acute hypoxemic respiratory failure, we observed improved 28-day and hospital mortality in those who received prone positioning, compared to those who did not. However, these findings do not imply causation. Further research is needed to clarify the role of prone positioning in this population.

Human microbiota in dengue infection: A narrative review

Dengue fever, a widespread mosquito-borne viral infection in tropical regions, typically manifests fever and gastrointestinal symptoms, including nausea, vomiting, and diarrhea. However, the human gut microbiota's role in dengue pathogenesis remains incompletely understood. Studies have demonstrated dysbiosis during dengue virus infection, characterized by increased abundance of potentially pathogenic bacteria like Bacteroidaceae and Proteobacteria, particularly during the critical phase. Furthermore, microbial translocation and leaky gut syndrome, characterized by the translocation of intestinal microbial products, have been observed in dengue patients and are associated with hypercytokinemia, plasma leakage, and disease severity. These findings underscore the necessity for an in-depth investigation into the role of human intestinal microbiota as a potential contributing factor in the pathogenesis and progression of dengue. Further research focusing on human intestinal microbiota, leaky gut syndrome, and the potential implications of treatment with oral bacteriotherapy, as previously observed in other viral diseases, is essential to clarify dengue pathology and evaluate new therapeutic strategies.

Blood Cells as a Cellular Biomarker for Mitochondrial Function in a Experimental Model of Acute Carbon Monoxide Poisoning with Treatment

INTRODUCTION

Carbon monoxide (CO) is a leading cause of environmental poisoning in the United States with substantial mortality and morbidity. The mechanism of CO poisoning is complex and includes hypoxia, inflammation, and mitochondrial dysfunction. Currently both biomarkers and therapies for CO poisoning are limited and require new approaches.

METHODS

Rats (~ 300 g) were divided into four groups of ten rodents per group (exposure): Control (room air), CO-400 (400 ppm), CO-1000 (1000 ppm) and CO-2000 (2000 ppm). Rodents received the assigned exposure through a secured tracheotomy tube over 120 min followed by 30 min of re-oxygenation at room air for a total of 150 min. Five additional rodents in each group were administered a succinate prodrug (NV354) at the start of exposure for the duration of the experiment until the reoxygenation period as separate experiments. Cortical brain tissue and whole blood were obtained for mitochondrial respiration. Stored plasma and snap frozen tissue stored at -80oC were used to obtain protein quantification with Western Blotting.

RESULTS

All animals in the Sham, CO-400, and CO-1000 groups survived until the end of the exposure period; no animals in the CO-2000 groups survived the exposure and were counted as attrition. We observed a dose-dependent decrease in key respiratory states in both isolated brain mitochondria and peripheral blood mononuclear cells (PBMCs), and, PBMCs respiration more positively correlated with isolated brain mitochondria when compared to carboxyhemoglobin (COHb). There was no significant difference in mitochondrial respiratory states in animals treated with NV354 compared to the untreated group.

CONCLUSIONS

The primary findings from this study include: (1) A dose-dependent decrease with key respiration states with higher concentrations of CO; (2) PBMCs had a higher correlation to isolated brain mitochondria respiration when compared to COHb; and (3) there was no treatment effect with the use of NV354.

Heart Rate Variability Applications in Medical Specialties: A Narrative Review

HRV is clinically considered to be a surrogate measure of the asymmetrical interplay of the sympathetic and parasympathetic nervous system. While HRV has become an increasingly measured variable through commercially-available wearable devices, HRV is not routinely monitored or utilized in healthcare settings at this time. The purpose of this narrative review is to discuss and evaluate the current research and potential future applications of HRV in several medical specialties, including critical care, cardiology, pulmonology, nephrology, gastroenterology, endocrinology, infectious disease, hematology and oncology, neurology and rehabilitation, sports medicine, surgery and anesthesiology, rheumatology and chronic pain, obstetrics and gynecology, pediatrics, and psychiatry/psychology. A narrative literature review was conducted with search terms including HRV and relevant terminology to the medical specialty in question. While HRV has demonstrated promise for some diagnoses as a non-invasive, easy to use, and cost-effective metric for early disease detection, prognosis and mortality prediction, disease monitoring, and biofeedback therapy, several issues plague the current literature. Substantial heterogeneity exists in the current HRV literature which limits its applicability in clinical practice. However, applications of HRV in psychiatry, critical care, and in specific chronic diseases demonstrate sufficient evidence to warrant clinical application regardless of the surmountable research issues. More data is needed to understand the exact impact of standardizing HRV monitoring and treatment protocols on patient outcomes in each of the clinical contexts discussed in this paper.