Apoptotic cell death in patients with sepsis, shock, and multiple organ dysfunction

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.

In Silico Exploration of Natural Antioxidants for Sepsis Drug Discovery

Sepsis, a life-threatening condition characterized by immune dysregulation and organ damage, remains a significant clinical challenge. Natural antioxidant compounds (NAOs) such as quercetin, EGCG, resveratrol, curcumin, and chlorogenic acid have shown promising anti-inflammatory and anti-apoptotic effects in preclinical models of sepsis and related conditions, yet the molecular mechanisms underlying their actions remain incompletely defined. In this study, we performed comprehensive molecular docking analyses to investigate the binding affinities and interaction profiles of these NAOs with three key proteins central to inflammatory and apoptotic signaling: Toll-like receptor 4 (TLR-4), interleukin-1 receptor-associated kinase 1 (IRAK1), and caspase-3. Our results demonstrate that all five compounds exhibit favorable binding affinities with these targets, forming multiple hydrogen bonds and hydrophobic interactions with critical active site residues. Notably, curcumin and EGCG consistently displayed the strongest binding affinities across the three proteins, with docking scores comparable to or surpassing those of reference inhibitors. Resveratrol demonstrated highly stable binding poses, particularly with caspase-3, while quercetin and chlorogenic acid showed moderate but reproducible affinities. Overall, this study provides new mechanistic insights into how NAOs may target central mediators of inflammation and cell death. Experimental validation is essential to confirm these interactions, assess binding affinities, and fully elucidate the therapeutic potential of NAOs in sepsis.

Gut integrity in intensive care: alterations in host permeability and the microbiome as potential therapeutic targets

BACKGROUND

The gut has long been hypothesized to be the "motor" of critical illness, propagating inflammation and playing a key role in multiple organ dysfunction. However, the exact mechanisms through which impaired gut integrity potentially contribute to worsened clinical outcome remain to be elucidated. Critical elements of gut dysregulation including intestinal hyperpermeability and a perturbed microbiome are now recognized as potential therapeutic targets in critical care.

MAIN BODY

The gut is a finely tuned ecosystem comprising ~ 40 trillion microorganisms, a single cell layer intestinal epithelia that separates the host from the microbiome and its products, and the mucosal immune system that actively communicates in a bidirectional manner. Under basal conditions, these elements cooperate to maintain a finely balanced homeostasis benefitting both the host and its internal microbial community. Tight junctions between adjacent epithelial cells selectively transport essential molecules while preventing translocation of pathogens. However, critical illness disrupts gut barrier function leading to increased gut permeability, epithelial apoptosis, and immune activation. This disruption is further exacerbated by a shift in the microbiome toward a "pathobiome" dominated by pathogenic microbes with increased expression of virulence factors, which intensifies systemic inflammation and accelerates organ dysfunction. Research has highlighted several potential therapeutic targets to restore gut integrity in the host, including the regulation of epithelial cell function, modulation of tight junction proteins, and inhibition of epithelial apoptosis. Additionally, microbiome-targeted therapies, such as prebiotics, probiotics, fecal microbiota transplantation, and selective decontamination of the digestive tract have also been extensively investigated to promote restoration of gut homeostasis in critically ill patients. Future research is needed to validate the potential efficacy of these interventions in clinical settings and to determine if the gut can be targeted in an individualized fashion.

CONCLUSION

Increased gut permeability and a disrupted microbiome are common in critical illness, potentially driving dysregulated systemic inflammation and organ dysfunction. Therapeutic strategies to modulate gut permeability and restore the composition of microbiome hold promise as novel treatments for critically ill patients.

Plasma proteomics in pediatric patients with sepsis- hopes and challenges

One of the main causes of morbidity and death in pediatric patients is sepsis. Of the 48.9 million cases of sepsis reported globally, 41.5% involve children under the age of five, with 2.9 million deaths associated with the disease. Clinicians must identify and treat patients at risk of sepsis or septic shock before late-stage organ dysfunction occurs since diagnosing sepsis in young patients is more difficult than in adult patients. As of right now, omics technologies that possess adequate diagnostic sensitivity and specificity can assist in locating biomarkers that indicate how the disease will progress clinically and how the patient will react to treatment. By identifying patients who are at a higher risk of dying or experiencing persistent organ dysfunction, risk stratification based on biomarkers generated from proteomics can enhance prognosis. A potentially helpful method for determining the proteins that serve as biomarkers for sepsis and formulating theories on the pathophysiological mechanisms behind complex sepsis symptoms is plasma proteomics.

A review of gut failure as a cause and consequence of critical illness

In critical illness, all elements of gut function are perturbed. Dysbiosis develops as the gut microbial community loses taxonomic diversity and new virulence factors appear. Intestinal permeability increases, allowing for translocation of bacteria and/or bacterial products. Epithelial function is altered at a cellular level and homeostasis of the epithelial monolayer is compromised by increased intestinal epithelial cell death and decreased proliferation. Gut immunity is impaired with simultaneous activation of maladaptive pro- and anti-inflammatory signals leading to both tissue damage and susceptibility to infections. Additionally, splanchnic vasoconstriction leads to decreased blood flow with local ischemic changes. Together, these interrelated elements of gastrointestinal dysfunction drive and then perpetuate multi-organ dysfunction syndrome. Despite the clear importance of maintaining gut homeostasis, there are very few reliable measures of gut function in critical illness. Further, while multiple therapeutic strategies have been proposed, most have not been shown to conclusively demonstrate benefit, and care is still largely supportive. The key role of the gut in critical illness was the subject of the tenth Perioperative Quality Initiative meeting, a conference to summarize the current state of the literature and identify key knowledge gaps for future study. This review is the product of that conference.

Siderophore-Functionalized Nanodrug for Treating Antibiotic-Resistant Bacteria

The development of nanodrugs targeting multidrug-resistant bacteria, while sparing the beneficial constituents of the microbiome, has emerged as a promising approach to combat disease and curb the rise of antimicrobial resistance. In this investigation, we devised a siderophore-functionalized nanodrug based on a gold nanoparticle construct (AuNP-NSC; Gold nanoparticle_N-heterocyclic_Siderophore_Cyanine7), offering an innovative treatment modality against drug-resistant bacterial pathogens. As a proof of concept, the efficacy of this nanodrug delivery and antimicrobial therapy was evaluated against the notoriously resistant bacterium P. aeruginosa. N-Heterocyclic carbenes (NHCs) exhibit a strong affinity for transition metals, forming highly stable complexes resistant to ligand displacement. The entry of siderophore-conjugated nanodrugs into bacteria is facilitated through specific receptors on the outer membrane. In our study, AuNP-NSC was specifically targeted and imported into resistant Gram-negative P. aeruginosa via binding with ferric iron. Treatment with the developed nanodrug significantly inhibited the proliferation of antibiotic-resistant P. aeruginosa, reducing bacterial counts by more than 95% and mitigating drug resistance. Furthermore, AuNP-NSC markedly diminished P. aeruginosa-induced skin lesions and forestalled systemic organ failure triggered by secondary sepsis in mouse models. These findings underscore the potential of nanodrugs as specialized therapeutic agents for the management of antibiotic-resistant bacterial infections.

The role of programmed cell death in organ dysfunction induced by opportunistic pathogens

Sepsis is a life-threatening condition resulting from pathogen infection and characterized by organ dysfunction. Programmed cell death (PCD) during sepsis has been associated with the development of multiple organ dysfunction syndrome (MODS), impacting various physiological systems including respiratory, cardiovascular, renal, neurological, hematological, hepatic, and intestinal systems. It is well-established that pathogen infections lead to immune dysregulation, which subsequently contributes to MODS in sepsis. However, recent evidence suggests that sepsis-related opportunistic pathogens can directly induce organ failure by promoting PCD in parenchymal cells of each affected organ. This study provides an overview of PCD in damaged organ and the induction of PCD in host parenchymal cells by opportunistic pathogens, proposing innovative strategies for preventing organ failure in sepsis.

Drp1-associated genes implicated in sepsis survival

Sepsis is a severe and life-threatening medical syndrome that can lead to organ failure and death. Despite advances in medical treatment, current therapies are often inadequate, with high septic mortality rates. Therefore, there is a critical need for reliable prognostic markers to be used in clinical settings to improve the management and outcomes of patients with sepsis. Recent studies have suggested that mitochondrial dynamics, including the processes of mitochondrial fission and fusion, are closely related to the severity of sepsis and the status of inflammation. By monitoring transcriptomic signals related to mitochondrial dynamics, new and reliable biomarkers can be engineered to more accurately predict sepsis survival risk. Such biomarkers would be invaluable in clinical settings, aiding healthcare providers in the early identification of high-risk patients and improving treatment strategies. To achieve this goal, we utilized the major mitochondrial fission regulatory protein dynamin-related protein 1 (Drp1, gene code DNM1L) and identified Drp1-associated genes that are enriched with sepsis survival genes. A 12-gene signature (GS) was established as a differentially expressed gene (DEG)-based GS. Next, we compared genes of proteins that interact with Drp1 to sepsis survival genes and identified 7 common genes, establishing a GS we term as protein-protein interaction (PPI)-based GS. To evaluate if these GSs can predict sepsis survival, we used publicly available human blood transcriptomic datasets from sepsis patients. We confirmed that both GSs can successfully predict sepsis survival in both discovery and validation cohorts with high sensitivity and specificity, with the PPI-based GS showing enhanced prognostic performance. Together, this study successfully engineers a new and validated blood-borne biomarker (PPI-based 7-gene GS) for sepsis survival risk prediction. This biomarker holds the potential for improving the early identification of high-risk sepsis patients and optimizing personalized treatment strategies to reduce sepsis mortality.

Intestinal Epithelial Cell-specific Knockout of METTL3 Aggravates Intestinal Inflammation in CLP Mice by Weakening the Intestinal Barrier

BACKGROUND

Many studies have demonstrated that the expression of methyltransferase- like 3 (METTL3) is altered in various inflammatory diseases. Its specific mechanistic role in the intestinal inflammatory response during sepsis remains limited and requires further investigation.

OBJECTIVES

Explore the potential mechanism of METTL3 in the intestinal inflammatory response during sepsis.

MATERIALS AND METHODS

Immunohistochemical analysis was utilized to detect the expression of METTL3 in the necrotic intestine of patients with intestinal necrosis and the small intestine of cecal ligation and puncture (CLP) mice. Mice were subjected to the CLP and Sham surgeries, intestine tissue was harvested and performed HE staining, and ELISA to examine intestinal inflammatory responses, while TUNEL staining was applied to detect intestinal cell apoptosis. Additionally, ELISA was used to detect diamine oxidase (DAO) and intestinal fatty acid binding protein (I-FABP) levels in intestinal tissue. Immunohistochemistry and RT-qPCR were also employed to examine the mRNA and protein expression levels of Zona Occludens 1 (ZO-1) and Claudin-1. Finally, transcriptomic sequencing was performed on the small intestine tissues of METTL3 Knock-out (KO) and Wild-type (WT) mice in response to sepsis.

RESULTS

METTL3 exhibited lower expression level in the necrotic intestine of patients and the small intestine of CLP mice. Loss of METTL3 in CLP mice triggered significantly higher expression of TNF-α and IL-18, down-regulated expression of ZO-1 and claudin-1, and decreased expression of DAO and I-FABP in the intestinal tissue. KEGG enrichment analysis showed that the differential genes were significantly enriched in immune-related pathways.

CONCLUSION

This study reveals a novel mechanism responsible for exacerbated intestinal inflammation orchestrated by METTL3. Particularly, METTL3 null mice displayed decreased ZO- 1 and Claudin-1 expression, which largely hampered intestinal epithelial barrier function, resulting in bacterial and toxin translocation and intestinal immune activation and inflammation against sepsis.

Time-dependent variation in immunoparalysis biomarkers among patients with sepsis and critical illness

Introduction

Immunoparalysis is a state of immune dysfunction characterized by a marked reduction in the immune system's responsiveness, often observed following severe infections, trauma, or critical illness. This study aimed to perform a longitudinal assessment of immune function over the initial two weeks following the onset of sepsis and critical illness.

Methods

We compared ex vivo-stimulated cytokine release from whole blood of critically ill patients to traditional markers of immunoparalysis, including monocyte Human Leukocyte Antigen (mHLA)-DR expression and absolute lymphocyte count (ALC). A total of 64 critically ill patients were recruited in a tertiary care academic medical setting, including 31 septic and 33 non-septic patients.

Results

While mHLA-DR expression significantly increased over time, this was primarily driven by the non-septic subset of critically ill patients. ALC recovery was more pronounced in septic patients. Ex vivo stimulation of blood from septic patients revealed significant increases in TNF and IL-6 production over time. However, interferon-gamma production varied depending on the ex vivo stimulant used, and after normalization of cytokine concentrations to lymphocyte counts, it did not show significant recovery over time from illness onset. No significant correlation was found between mHLA-DR expression and other immunoparalysis biomarkers.

Discussion

These findings suggest the need for more nuanced immune monitoring approaches beyond the traditional 'sepsis' versus 'non-sepsis' classifications in critically ill patients. Additionally, they provide further evidence of a potential window for targeted immunotherapy in the first weeks of critical illness.

Could P2X7 receptor be a potencial target in neonatal sepsis?

The United Nations Inter-Agency Group for Child Mortality Estimation (UNIGME) estimates that every year 2.5 million neonates die in their first month of life, accounting for nearly one-half of deaths in children under 5 years of age. Neonatal sepsis is the third leading cause of neonatal mortality. The worldwide burden of bacterial sepsis is expected to increase in the next decades due to the lack of effective molecular therapies to replace the administration of antibiotics whose efficacy is compromised by the emergence of resistant strains. In addition, prolonged exposure to antibiotics can have negative effects by increasing the risk of infection by other organisms. With the global burden of sepsis increasing and no vaccine nor other therapeutic approaches proved efficient, the World Health Organization (WHO) stresses the need for new therapeutic targets for sepsis treatment and infection prevention (WHO, A73/32). In response to this unresolved clinical issue, the P2X7 receptor (P2X7R), a key component of the inflammatory cascade, has emerged as a potential target for treating inflammatory/infection diseases. Indeed numerous studies have demonstrated the relevance of the purinergic system as a pharmacological target in addressing immune-mediated inflammatory diseases by regulating immunity, inflammation, and organ function. In this review, we analyze key features of sepsis immunopathophysiology focusing in neonatal sepsis and on how the immunomodulatory role of P2X7R could be a potential pharmacological target for reducing the burden of neonatal sepsis.

Increased Levels of Anti-Anisakis Antibodies During Hospital Admission in Septic Patients

BACKGROUND/OBJECTIVES

In a previous study, we described elevated anti-Anisakis IgG levels in septic patients in relation to disease severity. In this study, our objective was to analyze the evolution of anti-Anisakis immunoglobulins in septic patients during hospital admission and their association with αβ and γδ T cell subsets.

METHODS

We recruited 80 subjects: 40 patients with sepsis and 40 controls. αβ and γδ T cells were analyzed using flow cytometry. Apoptosis was also assessed, and anti-Anisakis antibodies were measured by ELISA in the sera of patients with sepsis and controls.

RESULTS

In the second analysis (7-10 after sepsis evolution), an increase in all specific antibody isotypes was identified in individuals with septic shock, except IgE. The levels of anti-Anisakis IgG and IgA were higher in the subjects with sepsis in the first analysis and continued to increase in the second analysis compared with the healthy control subjects. There was an increase in anti-Anisakis IgG and IgA levels in surviving patients and an increase in IgA levels in non-surviving patients. A rise in specific IgG and IgE levels was noted in the second analysis of patients with sepsis with αβ CD3+ T cell deficiency. Patients without γδ T cell deficiency had increased anti-Anisakis IgA levels 7-10 days after admission.

CONCLUSIONS

Our results suggest a previous infection by Anisakis that could be involved in the subsequent septic process and be related to patients who have negative cultures in which the pathogen causing sepsis has not been identified.

Toll-like receptor 4 damages the intestinal epithelial cells by activating endoplasmic reticulum stress in septic rats

Background

The severity of acute gastrointestinal injury (AGI) is a critical determinant of survival in sepsis. However, there is no specifically interventional management for gastrointestinal dysfunction. Toll-like Receptor 4 (TLR4) is an important contributor to sepsis-induced multiple organ dysfunction syndrome. So, we investigated the effect of TLR4 on leucine-rich repeat-containing G protein-coupled receptor 5 (Lgr5) + cells and goblet cells and its potential mechanism.

Methods

A cecal ligation and puncture (CLP) model reflecting the development of clinical sepsis was developed. Tak-242, a TLR4 inhibitor, was administered to septic rats at a dose of 3 mg/kg via intraperitoneal injection. Immunohistochemistry was performed to detect TLR4 and Lgr5+ cells. AB-PAS staining was performed to detect goblet cells. MUC1 and MUC2 secreted by goblet cells, biomarkers of endoplasmic reticulum (ER) stress and inflammatory cytokines in the intestine were detected by western blotting and real-time PCR.

Results

We found that the upregulation of the TLR4/NF-κB signaling pathway activated intestinal inflammatory response in sepsis. Meanwhile, the structure of intestinal mucosa was destroyed, Lgr5+ cells and goblet cells count were significantly reduced, and the secretory function of goblet cells also decreased. Further studies have found that TLR4 increased the levels of activating transcription factor-6 (ATF6), XBP1, ER chaperone (Bip) and CHOP, but did not activate the protein kinase RNA (PKR)-like ER kinase (P-PERK).

Conclusion

We concluded that the inhibition of TLR4/NF-κB signaling pathway can reduce intestinal inflammatory response, protect intestinal mucosa, protect Lgr5+ cells, goblet cells and relieve ER stress. Our findings suggest that Tak-242 protects Lgr5+ cells and goblet cells after sepsis, partly may be through the suppression of ER stress. Thus, inhibition of TLR4-mediated ER stress may be a promising therapy of septic AGI.

Mechanistic study of leukopenia treatment by Qijiao shengbai Capsule via the Bcl2/Bax/CASAPSE3 pathway

Background

Leukopenia can be caused by chemotherapy, which suppresses bone marrow function and can impact the effectiveness of cancer treatment. Qijiao Shengbai Capsule (QJSB) is commonly used to treat leukopenia, but the specific bioactive components and mechanisms of action are not well understood.

Objectives and results

This study aimed to analyze the active ingredients of QJSB and its potential targets for treating leukopenia using network pharmacology and molecular docking. Through a combination of serum pharmacochemistry, multi-omics, network pharmacology, and validation experiments in a murine leukopenia model, the researchers sought to understand how QJSB improves leukopenia. The study identified 16 key components of QJSB that act in vivo to increase the number of white blood cells in leukopenic mice. Multi-omics analysis and network pharmacology revealed that the PI3K-Akt and MAPK signaling pathways are important in the treatment of leukopenia with QJSB. Five specific targets (JUN, FOS, BCl-2, CASPAS-3) were identified as key targets.

Conclusion

Validation experiments confirmed that QJSB regulates genes related to cell growth and inhibits apoptosis, suggesting that apoptosis may play a crucial role in leukopenia development and that QJSB may improve immune function by regulating apoptotic proteins and increasing CD4+ T cell count in leukopenic mice.

Mitochondrial dysfunction in sepsis: mechanisms and therapeutic perspectives

Sepsis is a severe medical condition characterized by a systemic inflammatory response, often culminating in multiple organ dysfunction and high mortality rates. In recent years, there has been a growing recognition of the pivotal role played by mitochondrial damage in driving the progression of sepsis. Various factors contribute to mitochondrial impairment during sepsis, encompassing mechanisms such as reactive nitrogen/oxygen species generation, mitophagy inhibition, mitochondrial dynamics change, and mitochondrial membrane permeabilization. Damaged mitochondria actively participate in shaping the inflammatory milieu by triggering key signaling pathways, including those mediated by Toll-like receptors, NOD-like receptors, and cyclic GMP-AMP synthase. Consequently, there has been a surge of interest in developing therapeutic strategies targeting mitochondria to mitigate septic pathogenesis. This review aims to delve into the intricate mechanisms underpinning mitochondrial dysfunction during sepsis and its significant impact on immune dysregulation. Moreover, we spotlight promising mitochondria-targeted interventions that have demonstrated therapeutic efficacy in preclinical sepsis models.

Sepsis Impairs IFN-γ Production in CD8 T Cells through Changes in Local Chromatin Landscape

Sepsis is a complex condition of inflammatory and immune dysregulation, triggered by severe infection. In survivors, chronic inflammation and immune dysregulation linger, facilitating the emergence of infections. CD8 dysfunction contributes to immunosuppression in sepsis survivors. We devised an animal model that enabled us to identify and analyze CD8-intrinsic defects induced by sepsis. We adoptively transferred CD45.1 CD8 OT-I T cells into CD45.2 congenic mice and subjected them to cecal ligature and puncture, to induce abdominal sepsis. One month later, we isolated the transferred CD8 cells. Surface marker expression confirmed they had not been activated through the TCR. CD8 OT-I T cells isolated from septic (or sham-operated) mice were transferred to second recipients, which were challenged with OVA-expressing Listeria monocytogenes. We compared effector capacities between OT-I cells exposed to sepsis and control cells. Naive mice that received OT-I cells exposed to sepsis had higher bacterial burden and a shorter survival when challenged with OVA-expressing L. monocytogenes. OT-I cells isolated from septic mice produced less IFN-γ but had conserved activation, expansion potential, and cytotoxic function. We observed lower transcript levels of IFN-γ and of the long noncoding RNA Ifng-as1, a local regulator of the epigenetic landscape, in cells exposed to sepsis. Accordingly, local abundance of a histone modification characteristic of active promoter regions was reduced in sepsis-exposed CD8 T cells. Our results identify a mechanism through which inflammation in the context of sepsis affects CD8 T cell function intrinsically.

Oxidative stress, defective proteostasis and immunometabolic complications in critically ill patients

Oxidative stress (OS) develops in critically ill patients as a metabolic consequence of the immunoinflammatory and degenerative processes of the tissues. These induce increased and/or dysregulated fluxes of reactive species enhancing their pro-oxidant activity and toxicity. At the same time, OS sustains its own inflammatory and immunometabolic pathogenesis, leading to a pervasive and vitious cycle of events that contribute to defective immunity, organ dysfunction and poor prognosis. Protein damage is a key player of these OS effects; it generates increased levels of protein oxidation products and misfolded proteins in both the cellular and extracellular environment, and contributes to forms DAMPs and other proteinaceous material to be removed by endocytosis and proteostasis processes of different cell types, as endothelial cells, tissue resident monocytes-macrophages and peripheral immune cells. An excess of OS and protein damage in critical illness can overwhelm such cellular processes ultimately interfering with systemic proteostasis, and consequently with innate immunity and cell death pathways of the tissues thus sustaining organ dysfunction mechanisms. Extracorporeal therapies based on biocompatible/bioactive membranes and new adsorption techniques may hold some potential in reducing the impact of OS on the defective proteostasis of patients with critical illness. These can help neutralizing reactive and toxic species, also removing solutes in a wide spectrum of molecular weights thus improving proteostasis and its immunometabolic corelates. Pharmacological therapy is also moving steps forward which could help to enhance the efficacy of extracorporeal treatments. This narrative review article explores the aspects behind the origin and pathogenic role of OS in intensive care and critically ill patients, with a focus on protein damage as a cause of impaired systemic proteostasis and immune dysfunction in critical illness.

Unraveling the immune response of the spleen in sepsis using green-synthesized silver nanoparticles from pomegranate peel extracts

Sepsis is a serious disease characterized by an inappropriate host response to infection, resulting in widespread inflammation and systemic organ failure. The aim of this research is to investigate the possibility of pomegranate peel-derived silver nanoparticles (PGNP) as a potential alternative therapy for sepsis. Characterization using transmission electron microscopy revealed 10-30 nm spherical nanoparticles. In a rat model of sepsis, PGNP treatment improved spleen health, histology, and immune response as compared with septic rats. In rats treated with PGNP during sepsis, significant alterations in oxidative stress markers (p < .01) were observed. These included elevated levels of glutathione (0.63 ± 0.08 mmol/mg protein), reduced concentrations of nitric oxide (8.7 ± 0.8 μ mol/mg protein) and malondialdehyde (2.2 ± 0.3 nmol/mg protein), as well as increased activity of superoxide dismutase (159 ± 33 U/mg protein). Following PGNP administration, gene expression analysis revealed a decrease in spleen IL-1β, IL-6, and TNF-α, highlighting its anti-inflammatory potential. Furthermore, PGNP effectively controlled apoptosis-related genes (Bax, Bcl-2, and Casp3), indicating its role in cellular survival pathways. This study sheds light on the immunological regulation of the spleen during sepsis using PGNP, demonstrating its potential as a new effective treatment approach. The study emphasizes the necessity of continuing to investigate and develop alternative medicines, particularly in light of antibiotic resistance and the global impact of sepsis. RESEARCH HIGHLIGHTS: The study explored the potential medicinal benefits of pomegranate peel-derived silver nanoparticles (PGNP) in the treatment of sepsis. PGNP suppressed pro-inflammatory cytokines and enhanced the immune response. The study recommends PGNP as a viable substitute treatment.

Inflammation, Sepsis, and the Coagulation System

Sepsis has been a major health problem for centuries and it is still the leading cause of hospital deaths. Several studies in the past decades have identified numerous biochemical abnormalities in severe cases, and many of these studies provide evidence of the perturbation of the hemostatic system. This can result in complications, such as disseminated intravascular coagulation that can lead to multiorgan failure. Nevertheless, large clinical studies have demonstrated that the simple approach of inhibiting the coagulation processes by any means fails to provide significant improvement in the survival of septic patients. A cause of this failure could be the fact that in sepsis the major clinical problems result not primarily from the presence of the infective agent or enhanced coagulation but from the complex dysregulated systemic host response to pathogens. If this overt reaction is not fully deciphered, appropriate interference is highly unlikely and any improvement by conventional therapeutic interventions would be limited. Cellular activation in sepsis can be targeted by novel approaches like inhibition of the heterotypic cellular interactions of blood cells by targeting surface receptors or posttranscriptional control of the hemostatic system by noncoding ribonucleic acid (RNA) molecules. Stable RNA molecules can affect the expression of several proteins. Thus, it can be anticipated that modulation of microRNA production would result in a multitude of effects that may be beneficial in septic cases. Here, we highlight some of the recent diagnostic possibilities and potential novel routes of the dysregulated host response.

Molecular mechanisms of resveratrol and its silver nanoparticle conjugate in addressing sepsis-induced lung injury

Sepsis is a life-threatening condition characterized by a systemic inflammatory response to infection. Despite extensive research on its pathophysiology, effective therapeutic approaches remain a challenge. This study investigated the potential of resveratrol (RV) and silver nanoparticle-enhanced resveratrol (AgNP-RV) as treatments for sepsis-induced lung injury using a rat model of polymicrobial sepsis induced by cecal ligation and puncture (CLP). The study focused on evaluating changes in oxidative status (TAS, TOS, and OSI) and the expression of inflammatory and apoptotic markers (IL-1β, TNF-α, P2X7R, TLR4, Caspase-3, and Bcl-2) in lung tissue. Both RV and AgNP-RV demonstrated potential in mitigating oxidative stress, inflammation, and apoptosis, with AgNP-RV exhibiting greater efficacy than RV alone (p < 0.05). These findings were corroborated by histopathological analyses, which revealed reduced tissue damage in the RV- and AgNP-RV-treated groups. Our study highlights the therapeutic potential of RV and, particularly, AgNP-RV in combating sepsis-induced oxidative stress, inflammation, and apoptosis. It also underscores the promise of nanoparticle technology in enhancing therapeutic outcomes. However, further investigations are warranted to fully understand the mechanisms of action, especially concerning the role of the P2X7 receptor in the observed effects. Nonetheless, our research suggests that RV and AgNP-RV hold promise as novel strategies for sepsis management.

What we know about alterations in immune cells during sepsis in veterinary animals?

Sepsis is still one of the most common causes of death of animals and humans. It is marked by an aberrant immune response to infection, resulting in extensive inflammation, organ dysfunction, and, in severe instances, organ failure. Recognizable symptoms and markers of sepsis encompass substantial elevations in body temperature, respiratory rate, hemoglobin levels, and alterations in immune cell counts, including neutrophils, monocytes, and basophils, along with increases in certain acute-phase proteins. In contrast to human medicine, veterinarians must take into account some species differences. This article provides a comprehensive overview of changes in the immune system during sepsis, placing particular emphasis on species variations and exploring potential future drugs and interventions. Hence, understanding the intricate balance of the immune responses during sepsis is crucial to develop effective treatments and interventions to improve the chances of recovery in animals suffering from this serious condition.

Increased peritoneal B1-like cells during acute phase of human septic peritonitis

Sepsis is a life-threatening condition caused by dysregulated host responses to infection. Myeloid cell accumulation and lymphocyte decline are widely recognized phenomena in septic patients. However, the fate of specific immune cells remains unclear. Here, we report the results of a human explorative study of patients with septic peritonitis and patients undergoing abdominal surgery without sepsis. We analyzed pairwise peritoneal fluid and peripheral blood taken 24 h after surgery to characterize immediate immune cell changes. Our results show that myeloid cell expansion and lymphocyte loss occur in all patients undergoing open abdominal surgery, indicating that these changes are not specific to sepsis. However, B1-like lymphocytes were specifically increased in the peritoneal fluid of septic patients, correlating positively with sequential organ failure assessment (SOFA) and acute physiology and chronic health evaluation II (APACHE-II) clinical severity scores. In support of this notion, we identified an accumulation of peritoneal B1b lymphocytes in septic mice.

The Application Potential of the Regulation of Tregs Function by Irisin in the Prevention and Treatment of Immune-Related Diseases

Irisin is a muscle factor induced by exercise, generated through the proteolytic cleavage of the membrane protein fibronectin type III domain-containing protein 5 (FNDC-5). Numerous studies have shown that irisin plays a significant role in regulating glucose and lipid metabolism, inhibiting oxidative stress, reducing systemic inflammatory responses, and providing neuroprotection. Additionally, irisin can exert immunomodulatory functions by regulating regulatory T cells (Tregs). Tregs are a highly differentiated subset of mature T cells that play a key role in maintaining self-immune homeostasis and are closely related to infections, inflammation, immune-related diseases, and tumors. Irisin exerts persistent positive effects on Treg cell functions through various mechanisms, including regulating Treg cell differentiation and proliferation, improving their function, modulating the balance of immune cells, increasing the production of anti-inflammatory cytokines, and enhancing metabolic functions, thereby helping to maintain immune homeostasis and prevent immune-related diseases. As an important myokine, irisin interacts with receptors on the cell membrane, activating multiple intracellular signaling pathways to regulate cell metabolism, proliferation, and function. Although the specific receptor for irisin has not been fully identified, integrins are considered potential receptors. Irisin activates various signaling pathways, including AMPK, MAPK, and PI3K/Akt, through integrin receptors, thereby exerting multiple biological effects. These research findings provide important clues for understanding the mechanisms of irisin's action and theoretical basis for its potential applications in metabolic diseases and immunomodulation. This article reviews the relationship between irisin and Tregs, as well as the research progress of irisin in immune-related diseases such as multiple sclerosis, myasthenia gravis, acquired immune deficiency syndrome, type 1 diabetes, sepsis, and rheumatoid arthritis. Studies have revealed that irisin plays an important role in immune regulation by improving the function of Tregs, suggesting its potential application value in the treatment of immune-related diseases.

Time-Dependent Variation in Immunoparalysis Biomarkers Among Patients with Sepsis and Critical Illness

Immunoparalysis is a significant concern in patients with sepsis and critical illness, potentially leading to increased risk of secondary infections. This study aimed to perform a longitudinal assessment of immune function over the initial two weeks following the onset of sepsis and critical illness. We compared ex vivo stimulated cytokine release to traditional markers of immunoparalysis, including monocyte Human Leukocyte Antigen (mHLA)-DR expression and absolute lymphocyte count (ALC). A total of 64 critically ill patients were recruited in a tertiary care academic medical setting, including 31 septic and 33 non-septic patients. Results showed that while mHLA-DR expression significantly increased over time, this was primarily driven by the non-septic subset of critically ill patients. ALC recovery was more prominent in septic patients. Ex vivo stimulation revealed significant increases in TNF and IL-6 production over time in septic patients. However, IFNγ production varied with the stimulant used and did not show significant recovery when normalized to cell count. No significant correlation was found between mHLA-DR expression and other immunoparalysis biomarkers. These findings suggest the need for more nuanced immune monitoring approaches beyond the traditional 'sepsis' versus 'non-sepsis' classifications in critically ill patients. It also provided further evidence of a potential window for targeted immunotherapeutic interventions in the first week of critical illness.

Predicting Organ Dysfunction in Septic and Critically Ill Patients: A Prospective Cohort Study Using Rapid Ex Vivo Immune Profiling

OBJECTIVES

While cytokine response patterns are pivotal in mediating immune responses, they are also often dysregulated in sepsis and critical illness. We hypothesized that these immunological deficits, quantifiable through ex vivo whole blood stimulation assays, may be indicative of subsequent organ dysfunction.

DESIGN

In a prospective observational study, adult septic patients and critically ill but nonseptic controls were identified within 48 hours of critical illness onset. Using a rapid, ex vivo assay based on responses to lipopolysaccharide (LPS), anti-CD3/anti-CD28 antibodies, and phorbol 12-myristate 13-acetate with ionomycin, cytokine responses to immune stimulants were quantified. The primary outcome was the relationship between early cytokine production and subsequent organ dysfunction, as measured by the Sequential Organ Failure Assessment score on day 3 of illness (SOFAd3).

SETTING

Patients were recruited in an academic medical center and data processing and analysis were done in an academic laboratory setting.

PATIENTS

Ninety-six adult septic and critically ill nonseptic patients were enrolled.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Elevated levels of tumor necrosis factor and interleukin-6 post-endotoxin challenge were inversely correlated with SOFAd3. Interferon-gamma production per lymphocyte was inversely related to organ dysfunction at day 3 and differed between septic and nonseptic patients. Clustering analysis revealed two distinct immune phenotypes, represented by differential responses to 18 hours of LPS stimulation and 4 hours of anti-CD3/anti-CD28 stimulation.

CONCLUSIONS

Our rapid immune profiling technique offers a promising tool for early prediction and management of organ dysfunction in critically ill patients. This information could be pivotal for early intervention and for preventing irreversible organ damage during the acute phase of critical illness.

The emerging role of adaptor proteins in regulating innate immunity of sepsis

Sepsis is a life-threatening syndrome caused by a dysregulated immune response. A large number of adaptor proteins have been found to play a pivotal role in sepsis via protein-protein interactions, thus participating in inflammatory cascades, leading to the generation of numerous inflammatory cytokines, as well as oxidative stress and regulated cell death. Although available strategies for the diagnosis and management of sepsis have improved, effective and specific treatments are lacking. This review focuses on the emerging role of adaptor proteins in regulating the innate immunity of sepsis and evaluates the potential value of adaptor protein-associated therapeutic strategy for sepsis.

Association between intracellular adenosine triphosphate content of CD4+ T lymphocytes and mortality in sepsis patients: A prospective observational study

OBJECTIVE

This study aimed to link intracellular adenosine triphosphate content in CD4+ T lymphocytes (CD4+ iATP) with sepsis patient mortality, seeking a new predictive biomarker for outcomes and enhanced management.

METHODS

61 sepsis patients admitted to the Intensive Care Unit between October 2021 and November 2022 were enrolled. iATP levels were gauged using whole blood CD4+ T cells stimulated with mitogen PHA-L. Based on CD4+ iATP levels (<132.24 and ≥132.24 ng/mL), patients were categorized into two groups. The primary endpoint was all-cause mortality. To identify factors associated with mortality, both univariate and multivariate Cox proportional hazard analyses were conducted.

RESULTS

Of the patients, 40 had high CD4+ iATP levels (≥132.24 ng/mL) and 21 had low levels (<132.24 ng/mL). In a 28-day follow-up, 21 (34.4%) patients perished. Adjusting for confounders like SOFA score, APACHE II score, lactic acid, and albumin, those with low CD4+ iATP had three- to fivefold higher mortality risk compared to high CD4+ iATP patients (61.9% vs. 20.0%; hazard ratio [95% confidence interval], Model 1: 4.515 [1.276-15.974], p = .019, Model 2: 3.512 [1.197-10.306], p = .022). CD4+ iATP correlated positively with white blood cell and neutrophil counts but not with lymphocytes, CD3, and CD4 counts.

CONCLUSIONS

Low CD4+ iATP levels were associated with a higher risk of mortality in sepsis patients. Measurement of CD4+ iATP may serve as a useful tool for identifying patients at a higher risk of mortality and could potentially provide a basis for clinical treatment. Further research is warranted to fully elucidate the underlying mechanisms of this association.

Immunotherapy in the context of sepsis-induced immunological dysregulation

Sepsis is a clinical syndrome caused by uncontrollable immune dysregulation triggered by pathogen infection, characterized by high incidence, mortality rates, and disease burden. Current treatments primarily focus on symptomatic relief, lacking specific therapeutic interventions. The core mechanism of sepsis is believed to be an imbalance in the host's immune response, characterized by early excessive inflammation followed by late immune suppression, triggered by pathogen invasion. This suggests that we can develop immunotherapeutic treatment strategies by targeting and modulating the components and immunological functions of the host's innate and adaptive immune systems. Therefore, this paper reviews the mechanisms of immune dysregulation in sepsis and, based on this foundation, discusses the current state of immunotherapy applications in sepsis animal models and clinical trials.

Intestinal injury in paracetamol overdose (ATOM-8)

BACKGROUND AND AIM

Paracetamol, a widely used medication, is known for its delayed hepatotoxicity in cases of overdose. However, the potential for intestinal toxicity resulting from very high paracetamol concentrations during absorption is not well explored. This study aims to investigate the presence of intestinal toxicity and its correlation with observations in early and late paracetamol toxicity.

METHODS

Serial samples of 30 patients with acute paracetamol overdose (> 10 g or 200 mg/kg) were prospectively tested. Markers of enterocyte damage, including plasma intestinal fatty acid binding protein (IFABP) and selected gut-related microRNAs (miR-21, miR-122, miR-194, and miR-215), were analyzed. Sub-analysis was performed on patients presenting with hyperlactatemia defined as a lactate greater than 2 mmol/L within 12 h post ingestion.

RESULTS

In paracetamol overdose patients, median plasma IFABP was significantly elevated compared with healthy controls (720 μg/L [interquartile range, IQR, 533-1644] vs 270 μg/L [IQR 153-558], P < 0.001). Four patients had early hyperlactatemia and had significantly higher median plasma IFABP compared with those without early hyperlactatemia (3028 μg/L [IQR 1399-3556] vs 574 μg/L [IQR 526-943], P = 0.007). Furthermore, two microRNAs (miR-122 and miR-215) were downregulated in early hyperlactatemia (P = 0.019 and P = 0.006, respectively). Plasma IFABP concentrations correlated with paracetamol concentration (Spearman's r = 0.55) and lactate (r = 0.60).

CONCLUSIONS

Paracetamol overdose causes concentration-related intestinal toxicity, and this is a possible explanation for the early hyperlactatemia syndrome. Intestinal toxicity has potential impacts on pharmacokinetics of other agents ingested and on the evolution of hepatotoxicity. Further studies are required to explore the mechanisms and prognostic implications of intestinal toxicity.

NLRP6 negatively regulates host defense against polymicrobial sepsis

Introduction

Sepsis remains a major cause of death in Intensive Care Units. Sepsis is a life-threatening multi-organ dysfunction caused by a dysregulated systemic inflammatory response. Pattern recognition receptors, such as TLRs and NLRs contribute to innate immune responses. Upon activation, some NLRs form multimeric protein complexes in the cytoplasm termed "inflammasomes" which induce gasdermin d-mediated pyroptotic cell death and the release of mature forms of IL-1β and IL-18. The NLRP6 inflammasome is documented to be both a positive and a negative regulator of host defense in distinct infectious diseases. However, the role of NLRP6 in polymicrobial sepsis remains elusive.

Methods

We have used NLRP6 KO mice and human septic spleen samples to examine the role of NLRP6 in host defense in sepsis.

Results

NLRP6 KO mice display enhanced survival, reduced bacterial burden in the organs, and reduced cytokine/chemokine production. Co-housed WT and KO mice following sepsis show decreased bacterial burden in the KO mice as observed in singly housed groups. NLRP6 is upregulated in CD3, CD4, and CD8 cells of septic patients and septic mice. The KO mice showed a higher number of CD3, CD4, and CD8 positive T cell subsets and reduced T cell death in the spleen following sepsis. Furthermore, administration of recombinant IL-18, but not IL-1β, elicited excessive inflammation and reversed the survival advantages observed in NLRP6 KO mice.

Conclusion

These results unveil NLRP6 as a negative regulator of host defense during sepsis and offer novel insights for the development of new treatment strategies for sepsis.

Reframing sepsis immunobiology for translation: towards informative subtyping and targeted immunomodulatory therapies

Sepsis is a common and deadly condition. Within the current model of sepsis immunobiology, the framing of dysregulated host immune responses into proinflammatory and immunosuppressive responses for the testing of novel treatments has not resulted in successful immunomodulatory therapies. Thus, the recent focus has been to parse observable heterogeneity into subtypes of sepsis to enable personalised immunomodulation. In this Personal View, we highlight that many fundamental immunological concepts such as resistance, disease tolerance, resilience, resolution, and repair are not incorporated into the current sepsis immunobiology model. The focus for addressing heterogeneity in sepsis should be broadened beyond subtyping to encompass the identification of deterministic molecular networks or dominant mechanisms. We explicitly reframe the dysregulated host immune responses in sepsis as altered homoeostasis with pathological disruption of immune-driven resistance, disease tolerance, resilience, and resolution mechanisms. Our proposal highlights opportunities to identify novel treatment targets and could enable successful immunomodulation in the future.

Advances and Challenges in Sepsis Management: Modern Tools and Future Directions

Sepsis, a critical condition marked by systemic inflammation, profoundly impacts both innate and adaptive immunity, often resulting in lymphopenia. This immune alteration can spare regulatory T cells (Tregs) but significantly affects other lymphocyte subsets, leading to diminished effector functions, altered cytokine profiles, and metabolic changes. The complexity of sepsis stems not only from its pathophysiology but also from the heterogeneity of patient responses, posing significant challenges in developing universally effective therapies. This review emphasizes the importance of phenotyping in sepsis to enhance patient-specific diagnostic and therapeutic strategies. Phenotyping immune cells, which categorizes patients based on clinical and immunological characteristics, is pivotal for tailoring treatment approaches. Flow cytometry emerges as a crucial tool in this endeavor, offering rapid, low cost and detailed analysis of immune cell populations and their functional states. Indeed, this technology facilitates the understanding of immune dysfunctions in sepsis and contributes to the identification of novel biomarkers. Our review underscores the potential of integrating flow cytometry with omics data, machine learning and clinical observations to refine sepsis management, highlighting the shift towards personalized medicine in critical care. This approach could lead to more precise interventions, improving outcomes in this heterogeneously affected patient population.

Evaluation of circulating levels of miR-135a and miR-193 in patients with sepsis

BACKGROUND

Sepsis is a life-threatening condition where early diagnosis and prognostic awareness provide guidance for selecting the appropriate treatment strategies. A wide variety of biomarker-based studies in clinical medicine provide new insights into personalized medicine for sepsis patients. MiRNAs are endogenous non-coding RNA molecules that have been acting as great potential diagnostic, prognostic and therapeutic biomarkers in various diseases.

METHODS AND RESULTS

In the present study, the expression levels of two selected miRNAs, including miR-135a and miR-193, were evaluated for their prognostic potential in patients with sepsis. The circulating levels of miRNAs were quantified by quantitative PCR (qPCR) in patients with sepsis (n = 100) and age- and sex-matched healthy controls (n = 100). Statistical findings confirmed the valuable prognostic potential of miR-135a in patients with sepsis, while no significant difference was found between the miR-193 expression level in the patients with sepsis and the controls.

CONCLUSIONS

Circulating levels of miRNA-135a can serve a the prognostic biomarker for patients with sepsis. These findings highlight the importance of miRNAs as signatures in the personalized managements of sepsis.

A pairwise cytokine code explains the organism-wide response to sepsis

Sepsis is a systemic response to infection with life-threatening consequences. Our understanding of the molecular and cellular impact of sepsis across organs remains rudimentary. Here, we characterize the pathogenesis of sepsis by measuring dynamic changes in gene expression across organs. To pinpoint molecules controlling organ states in sepsis, we compare the effects of sepsis on organ gene expression to those of 6 singles and 15 pairs of recombinant cytokines. Strikingly, we find that the pairwise effects of tumor necrosis factor plus interleukin (IL)-18, interferon-gamma or IL-1β suffice to mirror the impact of sepsis across tissues. Mechanistically, we map the cellular effects of sepsis and cytokines by computing changes in the abundance of 195 cell types across 9 organs, which we validate by whole-mouse spatial profiling. Our work decodes the cytokine cacophony in sepsis into a pairwise cytokine message capturing the gene, cell and tissue responses of the host to the disease.

Cell death proteins in sepsis: key players and modern therapeutic approaches

Cell death proteins play a central role in host immune signaling during sepsis. These interconnected mechanisms trigger cell demise via apoptosis, necroptosis, and pyroptosis while also driving inflammatory signaling. Targeting cell death mediators with novel therapies may correct the dysregulated inflammation seen during sepsis and improve outcomes for septic patients.

Destabilisation of T cell-dependent humoral immunity in sepsis

Sepsis is a heterogeneous condition defined as life-threatening organ dysfunction caused by a dysregulated host response to infection. For some, sepsis presents as a predominantly suppressive disorder, whilst others experience a pro-inflammatory condition which can culminate in a 'cytokine storm'. Frequently, patients experience signs of concurrent hyper-inflammation and immunosuppression, underpinning the difficulty in directing effective treatment. Although intensive care unit mortality rates have improved in recent years, one-third of discharged patients die within the following year. Half of post-sepsis deaths are due to exacerbation of pre-existing conditions, whilst half are due to complications arising from a deteriorated immune system. It has been suggested that the intense and dysregulated response to infection may induce irreversible metabolic reprogramming in immune cells. As a critical arm of immune protection in vertebrates, alterations to the adaptive immune system can have devastating repercussions. Indeed, a marked depletion of lymphocytes is observed in sepsis, correlating with increased rates of mortality. Such sepsis-induced lymphopenia has profound consequences on how T cells respond to infection but equally on the humoral immune response that is both elicited by B cells and supported by distinct CD4+ T follicular helper (TFH) cell subsets. The immunosuppressive state is further exacerbated by functional impairments to the remaining lymphocyte population, including the presence of cells expressing dysfunctional or exhausted phenotypes. This review will specifically focus on how sepsis destabilises the adaptive immune system, with a closer examination on how B cells and CD4+ TFH cells are affected by sepsis and the corresponding impact on humoral immunity.

CTLA-4 Checkpoint Inhibition Improves Sepsis Survival in Alcohol-Exposed Mice

Chronic alcohol use increases morbidity and mortality in the setting of sepsis. Both chronic alcohol use and sepsis are characterized by immune dysregulation, including overexpression of T cell coinhibitory molecules. We sought to characterize the role of CTLA-4 during sepsis in the setting of chronic alcohol exposure using a murine model of chronic alcohol ingestion followed by cecal ligation and puncture. Results indicated that CTLA-4 expression is increased on CD4+ T cells isolated from alcohol-drinking septic mice as compared with either alcohol-drinking sham controls or water-drinking septic mice. Moreover, checkpoint inhibition of CTLA-4 improved sepsis survival in alcohol-drinking septic mice, but not water-drinking septic mice. Interrogation of the T cell compartments in these animals following pharmacologic CTLA-4 blockade, as well as following conditional Ctla4 deletion in CD4+ T cells, revealed that CTLA-4 deficiency promoted the activation and proliferation of effector regulatory T cells and the generation of conventional effector memory CD4+ T cells. These data highlight an important role for CTLA-4 in mediating mortality during sepsis in the setting of chronic alcohol exposure and may inform future approaches to develop targeted therapies for this patient population.

Melatonin as a Promising Anti-Inflammatory Agent in an In Vivo Animal Model of Sepsis-Induced Rat Liver Damage

Melatonin (MLT), earlier described as an effective anti-inflammatory agent, could be a beneficial adjunctive drug for sepsis treatment. This study aimed to determine the effects of MLT application in lipopolysaccharide (LPS)-induced sepsis in Wistar rats by determining the levels of liver tissue pro-inflammatory cytokines (TNF-α, IL-6) and NF-κB as well as hematological parameters indicating the state of sepsis. Additionally, an immunohistological analysis of CD14 molecule expression was conducted. Our research demonstrated that treatment with MLT prevented an LPS-induced increase in pro-inflammatory cytokines TNF-α and IL-6 and NF-κB levels, and in the neutrophil to lymphocyte ratio (NLR). On the other hand, MLT prevented a decrease in the blood lymphocyte number induced by LPS administration. Also, treatment with MLT decreased the liver tissue expression of the CD14 molecule observed after sepsis induction. In summary, in rats with LPS-induced sepsis, MLT was shown to be a significant anti-inflammatory agent with the potential to change the liver's immunological marker expression, thus ameliorating liver function.

Early, Persistent Lymphopenia Is Associated With Prolonged Multiple Organ Failure and Mortality in Septic Children

OBJECTIVES

Sepsis-associated immune suppression correlates with poor outcomes. Adult trials are evaluating immune support therapies. Limited data exist to support consideration of immunomodulation in pediatric sepsis. We tested the hypothesis that early, persistent lymphopenia predicts worse outcomes in pediatric severe sepsis.

DESIGN

Observational cohort comparing children with severe sepsis and early, persistent lymphopenia (absolute lymphocyte count < 1,000 cells/µL on 2 d between study days 0-5) to children without. The composite outcome was prolonged multiple organ dysfunction syndrome (MODS, organ dysfunction beyond day 7) or PICU mortality.

SETTING

Nine PICUs in the National Institutes of Health Collaborative Pediatric Critical Care Research Network between 2015 and 2017.

PATIENTS

Children with severe sepsis and indwelling arterial and/or central venous catheters.

INTERVENTIONS

Blood sampling and clinical data analysis.

MEASUREMENTS AND MAIN RESULTS

Among 401 pediatric patients with severe sepsis, 152 (38%) had persistent lymphopenia. These patients were older, had higher illness severity, and were more likely to have underlying comorbidities including solid organ transplant or malignancy. Persistent lymphopenia was associated with the composite outcome prolonged MODS or PICU mortality (66/152, 43% vs 45/249, 18%; p < 0.01) and its components prolonged MODS (59/152 [39%] vs 43/249 [17%]), and PICU mortality (32/152, 21% vs 12/249, 5%; p < 0.01) versus children without. After adjusting for baseline factors at enrollment, the presence of persistent lymphopenia was associated with an odds ratio of 2.98 (95% CI [1.85-4.02]; p < 0.01) for the composite outcome. Lymphocyte count trajectories showed that patients with persistent lymphopenia generally did not recover lymphocyte counts during the study, had lower nadir whole blood tumor necrosis factor-α response to lipopolysaccharide stimulation, and higher maximal inflammatory markers (C-reactive protein and ferritin) during days 0-3 ( p < 0.01).

CONCLUSIONS

Children with severe sepsis and persistent lymphopenia are at risk of prolonged MODS or PICU mortality. This evidence supports testing therapies for pediatric severe sepsis patients risk-stratified by early, persistent lymphopenia.

Restoring the infected powerhouse: Mitochondrial quality control in sepsis

Sepsis is a dysregulated host response to an infection, characterized by organ failure. The pathophysiology is complex and incompletely understood, but mitochondria appear to play a key role in the cascade of events that culminate in multiple organ failure and potentially death. In shaping immune responses, mitochondria fulfil dual roles: they not only supply energy and metabolic intermediates crucial for immune cell activation and function but also influence inflammatory and cell death pathways. Importantly, mitochondrial dysfunction has a dual impact, compromising both immune system efficiency and the metabolic stability of end organs. Dysfunctional mitochondria contribute to the development of a hyperinflammatory state and loss of cellular homeostasis, resulting in poor clinical outcomes. Already in early sepsis, signs of mitochondrial dysfunction are apparent and consequently, strategies to optimize mitochondrial function in sepsis should not only prevent the occurrence of mitochondrial dysfunction, but also cover the repair of the sustained mitochondrial damage. Here, we discuss mitochondrial quality control (mtQC) in the pathogenesis of sepsis and exemplify how mtQC could serve as therapeutic target to overcome mitochondrial dysfunction. Hence, replacing or repairing dysfunctional mitochondria may contribute to the recovery of organ function in sepsis. Mitochondrial biogenesis is a process that results in the formation of new mitochondria and is critical for maintaining a pool of healthy mitochondria. However, exacerbated biogenesis during early sepsis can result in accumulation of structurally aberrant mitochondria that fail to restore bioenergetics, produce excess reactive oxygen species (ROS) and exacerbate the disease course. Conversely, enhancing mitophagy can protect against organ damage by limiting the release of mitochondrial-derived damage-associated molecules (DAMPs). Furthermore, promoting mitophagy may facilitate the growth of healthy mitochondria by blocking the replication of damaged mitochondria and allow for post sepsis organ recovery through enabling mitophagy-coupled biogenesis. The remaining healthy mitochondria may provide an undamaged scaffold to reproduce functional mitochondria. However, the kinetics of mtQC in sepsis, specifically mitophagy, and the optimal timing for intervention remain poorly understood. This review emphasizes the importance of integrating mitophagy induction with mtQC mechanisms to prevent undesired effects associated with solely the induction of mitochondrial biogenesis.

Low monocytic HLA-DR expression in critically ill patients of sepsis: An indicator for antimicrobial and/or immunomodulatory intervention

BACKGROUND

Sepsis is a result of suppressed host immune response which leads to fatal multi-organ dysfunctionality. Low frequency of active monocytes or reduced expression of human leukocyte antigen (HLA)-DR on monocytes shows the suppressed immune response in sepsis patients. One of the well-studied markers in patients with sepsis is procalcitonin (PCT). The role of monocytic (m) HLA-DR expression has been monitored in sepsis and is being considered a marker of the severity of interim immuno-depression in these patients. The study describes the impact of HLA-DR expression on monocytes quantitatively using flow cytometry.

METHODS

In this prospective study, we quantified monocytes and their HLA-DR expression in 20 patients of sepsis admitted to the Intensive Care Unit (ICU). Serum levels of PCT and interleukin (IL)-6 production were also measured in these patients, and the results were compared with those in healthy controls.

RESULTS

Monocyte frequency calculated was higher in sepsis patients as compared to healthy controls, however, HLA-DR expressing monocytes were significantly reduced as was the mean fluorescence intensity (MFI) of HLA-DR. Contrastingly, IL-6 and PCT levels were significantly high in sepsis than controls. The results suggest that low HLA-DR expression, combined with PCT, is a better prognostic parameter in the early phase of sepsis.

CONCLUSION

Poor recovery of mHLA-DR may serve as an early guide for clinicians to assess the prognosis of sepsis patients and consider immunomodulatory therapy in its management.

Ex Vivo Endotoxin Stimulation of Blood for Predicting Survival in Patients With Sepsis: A Systematic Review

BACKGROUND

Sepsis is a syndrome characterized by host immune dysfunction, with the extent of immunoparalysis differing among patients. Lipopolysaccharide (LPS) is used commonly to assess the immune function of critically ill patients with sepsis. However, the reliability of this ex vivo diagnostic test in predicting clinical outcomes remains uncertain.

RESEARCH QUESTION

Does LPS-induced tumor necrosis factor (TNF) production from the blood of patients with sepsis predict mortality? Secondary outcomes included ICU and hospital stay durations, nosocomial infection rate, and organ recovery rate.

STUDY DESIGN AND METHODS

Human sepsis studies from various databases through April 2023 were evaluated. Inclusion criteria encompassed LPS-stimulated blood assays, English language, and reported clinical outcomes. Bias risk was evaluated using the Newcastle-Ottawa scale (NOS). Relationships between TNF production and mortality were analyzed at sepsis onset and during established sepsis, alongside secondary outcomes.

RESULTS

Of 11,580 studies, 17 studies (14 adult and three pediatric) were selected for analysis. Although 15 studies were evaluated as moderate to high quality using the NOS, it is important to note that some of these studies also had identifiable biases, such as unclear methods of participant recruitment. Nine studies detailed survival outcomes associated with LPS-induced TNF production at sepsis onset, whereas five studies explored TNF production's relationship with mortality during established sepsis. Trends suggested that lower LPS-induced TNF production correlated with higher mortality. However, heterogeneity in methodologies, especially the LPS assay protocol, hindered definitive conclusions. Publication bias was highlighted using funnel plot analysis. Concerning secondary outcomes, diminished TNF production might signify worsening organ dysfunction, although the link between cytokine production and nosocomial infection varied among studies.

INTERPRETATION

For functional immune profiling in sepsis, streamlined research methodologies are essential. This entails organizing cohorts based on microbial sources of sepsis, establishing standardized definitions of immunoparalysis, using consistent types and dosages of immune stimulants, adhering to uniform blood incubation conditions, and adopting consistent clinical outcomes.

A Cross-Sectional Survey Study on the Diagnosis and Management of Critical Illness-Induced Corticosteroid Insufficiency in Saudi Arabia

Background The presence of critical illness-induced corticosteroid insufficiency (CIRCI) is correlated with elevated concentrations of circulating biomarkers associated with inflammation and coagulation in multiple domains. The management of adrenal insufficiency remains a topic of ongoing debate and disagreement among endocrinologists and intensivists. This study aimed to assess the extent of understanding regarding CIRCI among endocrinologists and intensivists who are actively practicing in Saudi Arabia. Methods This is an online cross-sectional survey study that was conducted between June and August 2023 to assess knowledge of CIRCI among endocrinologists and intensivists working in Saudi Arabia. The questionnaire tool for this study was constructed based on a previous literature review. Binary logistic regression analysis was used to define factors that affect participants' knowledge of CIRCI. Results A total of 76 physicians were involved in this study. Around 32.9% (n= 25) of the participants described CIRCI correctly as an impairment of the hypothalamic-pituitary axis during critical illness. Around 35.5% (n=27) of the participants identified that widespread use of corticosteroids in critically ill patients prompted the need to revisit the concept, diagnosis, and management of CIRCI, and a similar proportion of the participants (35.5%) (n=27) identified that the role of corticosteroids in the management of CIRCI in critically ill patients may be beneficial in selected cases. Around 42.1% (n=32) of the participants identified that CIRCI is specific to critically ill patients while AI can occur in any individual. Around 17.1% (n=13) of the participants confirmed that there is no task force agreement on whether corticosteroids should be used in adult patients with sepsis but without shock. The mean knowledge score of the study participants was 3.6 (sd: 2.2) out of 10, which demonstrates a weak level of knowledge of CIRCI (36.0%). Binary logistic regression analysis identified that physicians from the southern and western regions were less likely to be knowledgeable of CIRCI compared to physicians from the central region (p< 0.05). Conclusion The study revealed that the level of familiarity with CIRCI among endocrinologists and intensivists in Saudi Arabia fell short of the desired benchmark. Clinicians may opt to utilize delta cortisol levels following cosyntropin administration and random plasma cortisol levels as diagnostic measures for CIRCI, instead of relying on plasma-free cortisol or salivary cortisol levels in conjunction with plasma total cortisol. Adherence to customized treatment protocols is crucial to attain the most favorable results for patients.

Sirt3 Deletion Increases Inflammation and Mortality in Polymicrobial Sepsis

Background: Sirtuin 3 (SIRT3) is a nicotinamide adenine dinucleotide (NAD)-dependent deacetylase that confers resilience to cellular stress by promoting mitochondrial activity. Mitochondrial dysfunction is a major driver of inflammation during sepsis. We hypothesize that Sirt3 expression improves survival in polymicrobial sepsis by mitigating the inflammatory response. Materials and Methods: Sirt3 knockout (S3KO) and wild-type (WT) mice underwent cecal ligation and puncture (CLP) or sham surgery. mRNA expression was quantified using quantitative polymerase chain reaction (qPCR) and protein expression was quantified using enzyme-linked immunosorbent assay (ELISA). Spectrophotometric assays were used to quantify serum markers of organ dysfunction. For in vitro studies, bone marrow-derived macrophages (BMDMs) were harvested from S3KO and WT mice and treated with lipopolysaccharide (LPS). Results: After CLP, hepatic Sirt3 levels decreased from baseline by nine hours and remained depressed at 24 hours. Peak serum interleukin-6 (IL-6) protein levels were higher in S3KO mice. In LPS-treated BMDMs, IL-6 mRNA levels peaked earlier in S3KO cells, although peak levels were comparable to WT. Although S3KO mice had decreased median survival after CLP compared with WT, there was no difference in five-day survival or organ dysfunction. Conclusions: Although S3KO mice initially had increased inflammation and mortality, this difference abated with time, and overall survival was comparable between the groups. This pattern is consistent with the timeline of sepsis-induced Sirt3 downregulation in WT mice, and suggests that Sirt3 downregulation occurring in sepsis is at least partially responsible for the initial hyperinflammatory response and subsequent mortality. Our data support upregulation of Sirt3 as a promising therapeutic strategy for further research in sepsis.

The effect of artesunate to reverse CLP-induced sepsis immunosuppression mice with secondary infection is tightly related to reducing the apoptosis of T cells via decreasing the inhibiting receptors and activating MAPK/ERK pathway

T cells play an important role in regulating immune system balance. Sepsis-associated immunosuppression causes apoptosis of T cells and a decrease in their number. Previously, artesunate was found to have an immunomodulatory effect on immunosuppression in model mice with cecal ligation and puncture (CLP)-induced sepsis. In the present study, mouse sepsis models of CLP and CLP with secondary infection were established and treated with artesunate in order to examine the effect of artesunate on adaptive immune response in sepsis-related immunosuppression. The results showed that artesunate treatment could increase the survival rate of CLP mice with secondary Pseudomonas aeruginosa infection, increase the bacterial clearance rate, and also increase the level of the pro-inflammatory cytokine TNF-α. In addition, artesunate resulted in an increase in the number of T cells, CD4+ T cells and CD8+ T cells, and inhibited CD4+ and CD8+ T-cell apoptosis. Artesunate was also found to inhibit the expression of the inhibitory receptors of PD-1, CTLA-4, and BTLA, but it did not affect the expression of Tim-3. Additionally, artesunate significantly increased the phosphorylated ERK level of CD4+ T cells and CD8+ T cells and inhibited mitochondrial pathway-mediated apoptosis in CLP mice with Pseudomonas aeruginosa infection. These findings reveal that artesunate has an immunomodulatory effect on the adaptive immune response in sepsis. These effects include an increase in the numbers of T cells, CD4+ T cells, and CD8+ T cells through inhibition of the expression of inhibitory receptors and promotion of the MAPK/ERK pathway.

Prognostic significance of lymphocyte subpopulations for ICU-acquired infections in patients with sepsis: a retrospective study

AIM

To determine the prognostic value of lymphocyte subpopulations in predicting intensive care unit (ICU)-acquired infections among patients admitted to the ICU with sepsis.

METHODS

Data on peripheral blood lymphocyte subpopulations [CD3+ T cells, CD4+ T cells, CD8+ T cells, CD16+CD56+ natural killer (NK) cells and CD19+ B cells] were collected continuously from 188 patients admitted to the study ICUs with sepsis between January 2021 and October 2022. Clinical data collected from these patients, including medical history, number of organ failures, severity of illness scores, and characteristics of ICU-acquired infections, were reviewed.

RESULTS

Lymphocyte subpopulation counts were significantly lower in patients who acquired an infection in the ICU compared with those who did not. Univariate analyses showed that the number of organ failures [odds ratio (OR) 3.37, 95% confidence interval (CI) 2.25-5.05], severity of illness scores [Sequential Organ Failure Assessment score - OR 1.69, 95% CI 1.41-2.02; Acute Physiology and Chronic Health Evaluation II score - OR 1.26, 95% CI 0.17-1.36], history of immunosuppressant use (OR 2.41, 95% CI 1.01-5.73) and lymphocyte subpopulations (CD3+ T cells - OR 0.60, 95% CI 0.51-0.71; CD4+ T cells - OR 0.51, 95% CI 0.41-0.63; CD8+ T cells - OR 0.32, 95% CI 0.22-0.47; CD16/CD56+ NK cells - OR 0.41, 95% CI 0.28-0.59; CD19+B cells - OR 0.52, 95% CI 0.37-0.75) were associated with ICU-acquired infections. Multi-factor logistic regression analysis demonstrated that APACHE II score (OR 1.25, 95% CI 1.13-1.38), CD3+ T cells (OR 0.66, 95% CI 0.54-0.81) and CD4+ T cells (OR 0.64, 95% CI 0.50-0.82) were independent significant risk factors for ICU-acquired infections.

CONCLUSION

Assessing CD3+ T cells and CD4+ T cells within 24 h of ICU admission may help in identification of patients at risk for developing ICU-acquired infections.

Feature augmentation and semi-supervised conditional transfer learning for early detection of sepsis

Early detection of Sepsis is crucial for improving patient outcomes, as it is a significant public health concern that results in substantial morbidity and mortality. However, despite the widespread use of the Sequential Organ Failure Assessment (SOFA) in clinical settings to identify sepsis, obtaining sufficient physiological data before onset remains challenging, limiting early detection of sepsis. To address this challenge, we propose an interpretable machine learning model, ITFG (Interpretable Tree-based Feature Generation), that leverages potential correlations between features based on existing knowledge to identify sepsis within six hours of onset using valuable and continuous physiological measures. Furthermore, we introduce a Semi-supervised Attention-based Conditional Transfer Learning (SAC-TL) framework to enhance the model's generality and enable it to be used for early warning of sepsis in the target domain with less information from the source domain. Our proposed approaches effectively address the problem of systematic feature sparsity and missing data, while also being practical for different degrees of generalizability. We evaluated our proposed approaches on open datasets, MIMIC and PhysioNet, obtaining AUC of 97.98% and 86.21%, respectively, demonstrating their effectiveness in different data environments and achieving the best early detection results.

Amphipathic Liponecrosis Impairs Bacterial Clearance and Causes Infection During Sterile Inflammation

BACKGROUND & AIMS

Although transient bacteremia is common during dental and endoscopic procedures, infections developing during sterile diseases like acute pancreatitis (AP) can have grave consequences. We examined how impaired bacterial clearance may cause this transition.

METHODS

Blood samples from patients with AP, normal controls, and rodents with pancreatitis or those administered different nonesterified fatty acids (NEFAs) were analyzed for albumin-unbound NEFAs, microbiome, and inflammatory cell injury. Macrophage uptake of unbound NEFAs using a novel coumarin tracer were done and the downstream effects-NEFA-membrane phospholipid (phosphatidylcholine) interactions-were studied on isothermal titration calorimetry.

RESULTS

Patients with infected AP had higher circulating unsaturated NEFAs; unbound NEFAs, including linoleic acid (LA) and oleic acid (OA); higher bacterial 16S DNA; mitochondrial DNA; altered β-diversity; enrichment in Pseudomonadales; and increased annexin V-positive myeloid (CD14) and CD3-positive T cells on admission. These, and increased circulating dead inflammatory cells, were also noted in rodents with unbound, unsaturated NEFAs. Isothermal titration calorimetry showed progressively stronger unbound LA interactions with aqueous media, phosphatidylcholine, cardiolipin, and albumin. Unbound NEFAs were taken into protein-free membranes, cells, and mitochondria, inducing voltage-dependent anion channel oligomerization, reducing ATP, and impairing phagocytosis. These were reversed by albumin. In vivo, unbound LA and OA increased bacterial loads and impaired phagocytosis, causing infection. LA and OA were more potent for these amphipathic interactions than the hydrophobic palmitic acid.

CONCLUSIONS

Release of stored LA and OA can increase their circulating unbound levels and cause amphipathic liponecrosis of immune cells via uptake by membrane phospholipids. This impairs bacterial clearance and causes infection during sterile inflammation.

Risk of malignant disease in 1-year sepsis survivors, a registry-based nationwide follow-up study

BACKGROUND

Cancer and sepsis share risk factors, and sepsis patients may have impaired immune response and increased morbidity long after intensive care. This study aimed to assess whether sepsis survivors are at increased risk for cancer. Our objective was to assess the incidence of new cancer in 1-year sepsis survivors and test the hypothesis that it is higher than that of the general population.

METHODS

We obtained data on ICU admissions of adult patients from Swedish Intensive care registry (SICR) from 2005 to 2017. We included patients with an explicit ICD-10 code for sepsis for the primary ICU admission. We obtained data on cancer diagnoses (2001-2018), death (2005-2018) and emigration (2005-2018) from Cancer and Cause of death and National Patient Registry databases of the National Board of Health and Welfare; age and sex-specific cancer incidence rates in Sweden from NORDCAN registry from 2006 to 2018. One-year survivors formed the final cohort, that was followed for new cancer diagnoses until death, emigration, or end of 2018, whichever came first. The main outcome measure was standardized incidence rate ratio (SIR) to compare the incidence of cancer in 1-year sepsis survivors to that in the general population (NORDCAN). We also performed several sensitivity analyses.

RESULTS

In a cohort of 18,550 1-year survivors, 75,427 person years accumulated during a median follow-up (FU) of 3.36 years (IQR 1.72-5.86), 6366 (34.3%) patients died, and 1625 (8.8%) patients were diagnosed with a new cancer after a median FU of 2.51 (IQR 1.09-4.48) years. The incidence ratio of any new cancer over the whole FU was 1.31 (95% CI 1.23-1.40) for men and 1.74 (95% CI 1.61-1.88) for women. The difference in incidence rates persisted in several sensitivity analyses. The SIRs were highest in cancers of gastrointestinal tract, genital organs, and skin.

CONCLUSION AND RELEVANCE

Compared to general population, incidence of cancer is increased in 1-year sepsis survivors. Variation in the findings depending on follow-up time suggests that factors other than sepsis alone are involved. Surveillance for malignant disease may be warranted in sepsis survivors.

Revealing the biological mechanism of acupuncture in alleviating excessive inflammatory responses and organ damage in sepsis: a systematic review

Sepsis is a systemic inflammation caused by a maladjusted host response to infection. In severe cases, it can cause multiple organ dysfunction syndrome (MODS) and even endanger life. Acupuncture is widely accepted and applied in the treatment of sepsis, and breakthroughs have been made regarding its mechanism of action in recent years. In this review, we systematically discuss the current clinical applications of acupuncture in the treatment of sepsis and focus on the mechanisms of acupuncture in animal models of systemic inflammation. In clinical research, acupuncture can not only effectively inhibit excessive inflammatory reactions but also improve the immunosuppressive state of patients with sepsis, thus maintaining immune homeostasis. Mechanistically, a change in the acupoint microenvironment is the initial response link for acupuncture to take effect, whereas PROKR2 neurons, high-threshold thin nerve fibres, cannabinoid CB2 receptor (CB2R) activation, and Ca2+ influx are the key material bases. The cholinergic anti-inflammatory pathway of the vagus nervous system, the adrenal dopamine anti-inflammatory pathway, and the sympathetic nervous system are key to the transmission of acupuncture information and the inhibition of systemic inflammation. In MODS, acupuncture protects against septic organ damage by inhibiting excessive inflammatory reactions, resisting oxidative stress, protecting mitochondrial function, and reducing apoptosis and tissue or organ damage.