Pharmacological effects of specialized pro-resolving mediators in sepsis-induced organ dysfunction: a narrative review.

Sepsis is a life-threatening syndrome of organ dysfunction, characterized by uncontrolled inflammatory response and immune dysregulation, often leading to multiple organ failure and even death. Specialized pro-resolving mediators (SPMs), which are typically thought to be formed via consecutive steps of oxidation of polyenoic fatty acids, have been shown to suppress inflammation and promote timely resolution of inflammation. They are mainly divided into four categories: lipoxins, resolvins, protectins, and maresins. The SPMs may improve the prognosis of sepsis by modulating the immune and inflammatory balance, thereby holding promise for clinical applications. However, their biosynthetic and pharmacological properties are very complex. Through a literature review, we aim to comprehensively elucidate the protective mechanisms of different SPMs in sepsis and its organ damage, in order to provide sufficient theoretical basis for the future clinical translation of SPMs.

Post-translational modifications in sepsis-induced organ dysfunction: mechanisms and implications.

As a grave and highly lethal clinical challenge, sepsis, along with its consequent multiorgan dysfunction, affects millions of people worldwide. Sepsis is a complex syndrome caused by a dysregulated host response to infection, leading to fatal organ dysfunction. An increasing body of evidence suggests that the pathogenesis of sepsis is both intricate and rapid and involves various cellular responses and signal transductions mediated by post-translational modifications (PTMs). Hence, a comprehensive understanding of the mechanisms and functions of PTMs within regulatory networks is imperative for understanding the pathological processes, diagnosis, progression, and treatment of sepsis. In this review, we provide an exhaustive and comprehensive summary of the relationship between PTMs and sepsis-induced organ dysfunction. Furthermore, we explored the potential applications of PTMs in the treatment of sepsis, offering a forward-looking perspective on the understanding of infectious diseases.

Role of sirtuins in sepsis and sepsis-induced organ dysfunction: A review.

Sepsis is defined as life-threatening organ dysfunction caused by a dysregulated host response to infection. Sepsis causes a high mortality rate and current treatment focuses on supportive therapies but lacks specific therapeutic targets. Notably, sirtuins (SIRTs) shows potential clinical application in the treatment of sepsis. It has been demonstrated that SIRTs, the nicotinamide adenine dinucleotide+(NAD+)-dependent deacetylases that regulate key signaling pathways in eukaryotes and prokaryotes, are involved in a variety of biological processes. To date, seven mammalian yeast Sir2 homologs have been identified. SIRTs can regulate inflammation, oxidative stress, apoptosis, autophagy, and other pathways that play important roles in sepsis-induced organ dysfunction. However, the existing studies on SIRTs in sepsis are too scattered, and there is no relevant literature to integrate them. This review innovatively summarizes the different mechanisms of SIRTs in sepsis organ dysfunction according to the different systems, and focuses on SIRT agonists, inhibitors, and targeted drugs that have been proved to be effective in the treatment of sepsis, so as to integrate the clinical research and basic research closely. We searched PubMed for all literature related to SIRTs and sepsis since its inception using the following medical subject headings: sirtuins, SIRTs, and sepsis. Data on the mechanisms of SIRTs in sepsis-induced organ damage and their potential as targets for disease treatment were extracted.

Effect of Bovine Lactoferrin Treatment on Iron Homeostasis and Gene Expression Changes in Multiple Organ Dysfunctions During Wound Healing Process in Rats.

BACKGROUND: Injury systemically disrupts the homeostatic balance and can cause organ failure. LF mediates both iron-dependent and iron-independent mechanisms, and the role of LF in regulating iron homeostasis is vital in terms of metabolism. OBJECTIVES: In this study, we evaluated the organ-level effect and gene expression change of bLf in the cutaneous repair process. MATERIALS AND METHODS: An excisional full-thickness skin defect (FTSD) wound model was created in male Sprague Dawley rats (180-250 g) (n = 48) fed a high-fat diet (HFD) and the PHGPx, SLC7A11 and SLC40A1 genes and iron metabolism were evaluated. The animals were randomly divided into 6 groups: 1- Control, 2- bLf (200 mg/kg/day, oral), 3- FTSD (12 mm in diameter, dorsal), 4- HFD + bLf, 5- HFD + FTSD, 6- HFD + FTSD + bLf. Histologically, iron accumulation was demonstrated by Prussian blue staining in the liver, kidney, and intestinal tissues. Gene expression analysis was performed with qPCR. RESULTS: Histologically, iron accumulation was demonstrated by Prussian blue staining in the liver, kidney, and intestinal tissues. Prussian blue reactions were detected in the kidney. PHPGx and SLC7A11 genes in kidney and liver tissue were statistically significant (P < 0.05) except for the SLC40A1 gene (P > 0.05). Expression changes of the three genes were not statistically significant in analyses of rat intestinal tissue (P = 0.057). CONCLUSION: In the organ-level ferroptotic damage mechanism triggered by wound formation. BLf controls the expression of three genes and manages iron deposition in these three tissues. In addition, it suppressed the increase in iron that would drive the cell to ferroptosis and anemia caused by inflammation, thereby eliminating iron deposition in the tissues.

[Study on multiple organ injury induced by Haematitum in mice].

Haematitum is a commonly used mineral medicine. It is toxic, as recorded in the second volume of Chinese Materia Medica. Therefore, it should not be taken for a long time. In this study, the effects of Haematitum and calcined Haematitum on multiple organ injuries in mice were investigated, and the mechanism of the toxicity of the related organs was explored by metabolomics. The mice were randomly divided into the control group, Haematitum low-dose group(ZS-L group), Haematitum high-dose group(ZS-H group), and calcined Haematitum high-dose group(DZS-H group), with 12 mice in each group. Haematitum decoction was given by continuous intragastric administration for 10 days. Then the life situation was observed, and samples were taken to detect various indicators. The results showed that the ZS-H group showed obvious toxicity, with different degrees of toxicity damage in the intestinal tract,liver, spleen, and lung. ZS-L group had no toxic reaction. The toxicity of the DZS-H group was significantly reduced, and only the lung was damaged. Metabolomics technology was used to detect the lung tissue of mice in the control group and the ZS-H group, and a total of 15 kinds of significant difference metabolites were detected, mainly involved in choline metabolism in cancer, sphingolipid metabolism, and glycerophospholipid metabolism. Immunohistochemical results showed that the INSIG1 protein expression level in the lung tissue of mice in the ZS-H group was significantly higher than that in the control group. In summary, large doses and long-time use of Haematitum decoction will cause a variety of organ damage, and the same dose of calcined Haematitum is less toxic than Haematitum. In addition, a low dose of Haematitum has no obvious toxic effect. The dysfunction of lipid metabolic pathways such as sphingolipid and glycerophospholipid metabolism may be an important factor in Haematitum-induced pulmonary toxicity. This study provides a reference for further research on the mechanism of Haematitum pulmonary toxicity.

From Molecular Mechanisms to Clinical Therapy: Understanding Sepsis-Induced Multiple Organ Dysfunction.

Sepsis-induced multiple organ dysfunction arises from the highly complex pathophysiology encompassing the interplay of inflammation, oxidative stress, endothelial dysfunction, mitochondrial damage, cellular energy failure, and dysbiosis. Over the past decades, numerous studies have been dedicated to elucidating the underlying molecular mechanisms of sepsis in order to develop effective treatments. Current research underscores liver and cardiac dysfunction, along with acute lung and kidney injuries, as predominant causes of mortality in sepsis patients. This understanding of sepsis-induced organ failure unveils potential therapeutic targets for sepsis treatment. Various novel therapeutics, including melatonin, metformin, palmitoylethanolamide (PEA), certain herbal extracts, and gut microbiota modulators, have demonstrated efficacy in different sepsis models. In recent years, the research focus has shifted from anti-inflammatory and antioxidative agents to exploring the modulation of energy metabolism and gut microbiota in sepsis. These approaches have shown a significant impact in preventing multiple organ damage and mortality in various animal sepsis models but require further clinical investigation. The accumulation of this knowledge enriches our understanding of sepsis and is anticipated to facilitate the development of effective therapeutic strategies in the future.

The significant mechanism and treatments of cell death in heatstroke.

With global warming, extreme environmental heat is becoming a social issue of concern, which can cause adverse health results including heatstroke (HS). Severe heat stress is characterized by cell death of direct heat damage, excessive inflammatory responses, and coagulation disorders that can lead to multiple organ dysfunction (MODS) and even death. However, the significant pathophysiological mechanism and treatment of HS are still not fully clear. Various modes of cell death, including apoptosis, pyroptosis, ferroptosis, necroptosis and PANoptosis are involved in MODS induced by heatstroke. In this review, we summarized molecular mechanism, key transcriptional regulation as for HSF1, NRF2, NF-κB and PARP-1, and potential therapies of cell death resulting in CNS, liver, intestine, reproductive system and kidney injury induced by heat stress. Understanding the mechanism of cell death provides new targets to protect multi-organ function in HS.

Unveiling the Role of Exosomes in the Pathophysiology of Sepsis: Insights into Organ Dysfunction and Potential Biomarkers.

Extracellular vesicles (EVs) are tools for intercellular communication, mediating molecular transport processes. Emerging studies have revealed that EVs are significantly involved in immune processes, including sepsis. Sepsis, a dysregulated immune response to infection, triggers systemic inflammation and multi-organ dysfunction, posing a life-threatening condition. Although extensive research has been conducted on animals, the complex inflammatory mechanisms that cause sepsis-induced organ failure in humans are still not fully understood. Recent studies have focused on secreted exosomes, which are small extracellular vesicles from various body cells, and have shed light on their involvement in the pathophysiology of sepsis. During sepsis, exosomes undergo changes in content, concentration, and function, which significantly affect the metabolism of endothelia, cardiovascular functions, and coagulation. Investigating the role of exosome content in the pathogenesis of sepsis shows promise for understanding the molecular basis of human sepsis. This review explores the contributions of activated immune cells and diverse body cells' secreted exosomes to vital organ dysfunction in sepsis, providing insights into potential molecular biomarkers for predicting organ failure in septic shock.

YL-109 attenuates sepsis-associated multiple organ injury through inhibiting the ERK/AP-1 axis and pyroptosis by upregulating CHIP.

Sepsis is a severe inflammatory disorder that can lead to life-threatening multiple organ injury. Lipopolysaccharide (LPS)-induced inflammation is the leading cause of multiple organ failure in sepsis. This study aimed to explore the effect of a novel agent, 2-(4-hydroxy-3-methoxyphenyl)-benzothiazole (YL-109), on LPS-induced multiple organ injury and the molecular mechanisms underlying these processes. The results showed that YL-109 protected against LPS-induced high mortality, cardiac dysfunction, pulmonary and intestinal injury through inhibiting the proinflammatory response, NLRP3 expression and pyroptosis-associated indicators in mouse tissues. YL-109 suppressed LPS-initiated cytokine release, pyroptosis and pyroptosis-related protein expression in HL-1, IEC-6 and MLE-12 cells, which was consistent with the results of the in vivo experiments. Mechanistically, YL-109 reduces phosphorylated ERK (extracellular signal-regulated kinase) levels and NF-κB activation, which are achieved through upregulating CHIP (carboxy terminus of Hsc70-interacting protein) expression, thereby inhibiting c-Jun and c-Fos activation as well as NLRP3 expression. As an E3 ligase, CHIP overexpression obviously promoted the degradation of phosphorylated ERK and inhibited the expression of NF-κB-mediated NLRP3 in cells stimulated with LPS. The protective effects of YL-109 against cardiac, pulmonary and intestinal damage, inflammation and pyroptosis caused by LPS were eliminated in CHIP knockout mice. Our results not only reveal the protective effect and molecular mechanism of YL-109 against LPS-mediated organs damage but also provide additional insights into the effect of CHIP on negatively regulating pyroptosis and inflammatory pathways.

Lung endothelium, tau, and amyloids in health and disease.

Lung endothelia in the arteries, capillaries, and veins are heterogeneous in structure and function. Lung capillaries in particular represent a unique vascular niche, with a thin yet highly restrictive alveolar-capillary barrier that optimizes gas exchange. Capillary endothelium surveys the blood while simultaneously interpreting cues initiated within the alveolus and communicated via immediately adjacent type I and type II epithelial cells, fibroblasts, and pericytes. This cell-cell communication is necessary to coordinate the immune response to lower respiratory tract infection. Recent discoveries identify an important role for the microtubule-associated protein tau that is expressed in lung capillary endothelia in the host-pathogen interaction. This endothelial tau stabilizes microtubules necessary for barrier integrity, yet infection drives production of cytotoxic tau variants that are released into the airways and circulation, where they contribute to end-organ dysfunction. Similarly, beta-amyloid is produced during infection. Beta-amyloid has antimicrobial activity, but during infection it can acquire cytotoxic activity that is deleterious to the host. The production and function of these cytotoxic tau and amyloid variants are the subject of this review. Lung-derived cytotoxic tau and amyloid variants are a recently discovered mechanism of end-organ dysfunction, including neurocognitive dysfunction, during and in the aftermath of infection.

Relationship of circulating levels of long-chain fatty acids to persistent organ failure in acute pancreatitis.

During acute pancreatitis (AP), free fatty acids (FFAs) are liberated from circulating triglycerides (TG) and injured adipocytes by pancreatic lipase. Circulating FFAs have been suspected as a source of systemic lipotoxicity in AP. However, assessment of FFAs is difficult and time-consuming, and little is known about relative levels of FFAs between patients with different severities of AP and controls. This study's aims were to assess early circulating levels of FFAs, (both saturated and unsaturated) in patients with AP vs. controls, and associations between FFA levels and AP severity. Serum samples from patients with AP were collected at enrollment (day 1 of hospital stay); serum samples were also collected from controls. FFAs including palmitic, palmitoleic, stearic, oleic, and linoleic acid were extracted and quantitated using gas chromatography separation. Severity of AP was determined by Revised Atlanta Classification. Differences in FFA levels and percentages of total FFAs were assessed between patients with AP and controls and patients with AP of different severity grades. A total of 93 patients with AP (48 female, 52%) and 29 controls (20 female, 69%) were enrolled. Of the patients with AP, 74 had mild/moderate and 19 had severe AP. Serum levels of all FFAs except stearic acid were significantly higher in patients with AP compared with controls. A strong and independent association between elevated palmitoleic acid levels and severe AP was found. Serum unsaturated FFA levels, specifically palmitoleic acid, appear to correlate with severe AP. These findings have potential clinical implications for targeted AP therapies.NEW & NOTEWORTHY Drivers of the inflammatory response in acute pancreatitis remain incompletely understood. Unsaturated fatty acids, specifically palmitoleic, appear to have an association with more severe acute pancreatitis. This finding presents a new clinical understanding of fatty acid toxicity and highlights a potential future target for treatment in severe acute pancreatitis.

The Novel Compound SUL-138 Counteracts Endothelial Cell and Kidney Dysfunction in Sepsis by Preserving Mitochondrial Function.

Sepsis is defined as a dysregulated host response leading to organ dysfunction, which may ultimately result in the patient's death. Mitochondrial dysfunction plays a key role in developing organ dysfunction in sepsis. In this study, we explored the efficacy of the novel mitochondrial protective compound, SUL-138, in sepsis models in HUVECs and mice. In LPS-challenged HUVECs, SUL-138 preserved mitochondrial membrane potential and oxygen consumption and limited mitochondrial oxidative stress, resulting in increased survival at 48 h. Further, SUL-138 dampened the LPS-induced expression of IL-1ß, but not of NLRP3, and IL-18 in HUVECs. Sepsis in mice induced by cecal ligation and puncture (CLP) led to a lower mitochondrial membrane potential and increased levels of mitochondrial oxidative stress in the kidney, which SUL-138 limited. In addition, SUL-138 mitigated the CLP-induced increase in kidney dysfunction markers NGAL and urea. It dampened the rise in kidney expression of IL-6, IL-1ß, and ICAM-1, but not TNF-α and E-selectin. Yet, SUL-138 limited the increase in plasma levels of IL-6 and TNF-α of CLP mice. These results demonstrate that SUL-138 supports mitochondrial function, resulting in a limitation of systemic inflammation and preservation of kidney function.

Extracellular vesicles participate in the pathogenesis of sepsis.

Sepsis is one of the leading causes of mortality worldwide and is defined as life-threatening organ dysfunction caused by a dysregulated host response to infection. The early diagnosis and effective treatment of sepsis still face challenges due to its rapid progression, dynamic changes, and strong heterogeneity among different individuals. To develop novel strategies to control sepsis, a better understanding of the complex mechanisms of sepsis is vital. Extracellular vesicles (EVs) are membrane vesicles released from cells through different mechanisms. In the disease state, the number of EVs produced by activated or apoptotic cells and the cargoes they carry were altered. They regulated the function of local or distant host cells in autocrine or paracrine ways. Current studies have found that EVs are involved in the occurrence and development of sepsis through multiple pathways. In this review, we focus on changes in the cargoes of EVs in sepsis, the regulatory roles of EVs derived from host cells and bacteria, and how EVs are involved in multiple pathological processes and organ dysfunction in sepsis. Overall, EVs have great application prospects in sepsis, such as early diagnosis of sepsis, dynamic monitoring of disease, precise therapeutic targets, and prevention of sepsis as a vaccine platform.

SHOCK INDUCES ENDOTHELIAL PERMEABILITY AFTER TRAUMA THROUGH INCREASED ACTIVATION OF RHOA GTPASE.

ABSTRACT: Introduction: Severely injured patients develop a dysregulated inflammatory state characterized by vascular endothelial permeability, which contributes to multiple organ failure. To date, however, the mediators of and mechanisms for this permeability are not well established. Endothelial permeability in other inflammatory states such as sepsis is driven primarily by overactivation of the RhoA GTPase. We hypothesized that tissue injury and shock drive endothelial permeability after trauma by increased RhoA activation leading to break down of endothelial tight and adherens junctions. Methods: Human umbilical vein endothelial cells (HUVECs) were grown to confluence, whereas continuous resistance was measured using electrical cell-substrate impedance sensing (ECIS) Z-Theta technology, 10% ex vivo plasma from severely injured trauma patients was added, and resistance measurements continued for 2 hours. Areas under the curve (AUCs) were calculated from resistance curves. For GTPase activity analysis, HUVECs were grown to confluence and incubated with 10% trauma plasma for 5 minutes before harvesting of cell lysates. Rho and Rac activity were determined using a G-LISA assay. Significance was determined using Mann-Whitney tests or Kruskal-Wallis test, and Spearman ρ was calculated for correlations. Results: Plasma from severely injured patients induces endothelial permeability with plasma from patients with both severe injury and shock contributing most to this increased permeability. Surprisingly, Injury Severity Score (ISS) does not correlate with in vitro trauma-induced permeability (-0.05, P > 0.05), whereas base excess (BE) does correlate with permeability (-0.47, P = 0.0001). The combined impact of shock and injury resulted in a significantly smaller AUC in the injury + shock group (ISS > 15, BE < -9) compared with the injury only (ISS > 15, BE > -9; P = 0.04) or minimally injured (ISS < 15, BE > -9; P = 0.005) groups. In addition, incubation with injury + shock plasma resulted in higher RhoA activation ( P = 0.002) and a trend toward decreased Rac1 activation ( P = 0.07) compared with minimally injured control. Conclusions: Over the past decade, improved early survival in patients with severe trauma and hemorrhagic shock has led to a renewed focus on the endotheliopathy of trauma. This study presents the largest study to date measuring endothelial permeability in vitro using plasma collected from patients after traumatic injury. Here, we demonstrate that plasma from patients who develop shock after severe traumatic injury induces endothelial permeability and increased RhoA activation in vitro . Our ECIS model of trauma-induced permeability using ex vivo plasma has potential as a high throughput screening tool to phenotype endothelial dysfunction, study mediators of trauma-induced permeability, and screen potential interventions.

Reduce, Reuse, Recycle, Run ! : 4 Rs to improve cardiac health in advanced age.

During the aging process damaged/dysfunctional proteins and organelles accumulate and contribute to organ dysfunction. Luckily, there is a conserved intracellular process to reuse and recycle these dysregulated cellular components termed macroautophagy (autophagy). Unfortunately, strong evidence indicates autophagy is compromised with aging, protein quality control is jeopardized, and resultant proteotoxicity can contribute significantly to age-associated organ dysfunction. Are there interventions that can re-establish autophagic flux that is otherwise impaired with aging? With particular regard to the heart, here we review evidence that caloric-restriction, the polyamine spermidine, and the mTOR inhibitor rapamycin, even when initiated late-in-life, restore cardiomyocyte autophagy to an extent that lessens age-associated cardiac dysfunction. Cho et al. provide a physiological intervention to this list i.e., regular physical exercise initiated late-in-life boosts cardiomyocyte autophagic flux and rejuvenates cardiac function in male mice. While this study provides strong evidence for a mechanism whereby heightened physical activity can lead to improved heart health in the context of aging, (i) only male mice were studied; (ii) the intensity of exercise-training might not be suitable for all; and (iii) mice with aging-associated comorbidities were not investigated. Nonetheless, Cho et al. provide robust evidence that a low-cost and simple behavioral intervention initiated late-in-life improves cardiomyocyte autophagic flux and rejuvenates cardiac function.

DNA-PKcs promotes sepsis-induced multiple organ failure by triggering mitochondrial dysfunction.

INTRODUCTION: Multiple organ failure is the commonest cause of death in septic patients. OBJECTIVES: This study was undertaken in an attempt to elucidate the functional importance of DNA-dependent protein kinase catalytic subunit (DNA-PKcs) on mitochondrial dysfunction associated with the development and progression of sepsis-related multiple organ dysfunction syndrome (MODS). METHODS: Cardiomyocyte-specific DNA-PKcs knockout (DNA-PKcsCKO) mice, liver-specific DNA-PKcs knockout (DNA-PKcsLKO) mice, and kidney tubular cell-specific DNA-PKcs knockout (DNA-PKcsTKO) mice were used to generate an LPS-induced sepsis model. Echocardiography, serum biochemistry, and tissue microscopy were used to analyze organ damage and morphological changes induced by sepsis. Mitochondrial function and dynamics were determined by qPCR, western blotting, ELISA, and mt-Keima and immunofluorescence assays following siRNA-mediated DNA-PKCs knockdown in cardiomyocytes, hepatocytes, and kidney tubular cells. RESULTS: DNA-PKcs deletion attenuated sepsis-mediated myocardial damage through improving mitochondrial metabolism. Loss of DNA-PKcs protected the liver against sepsis through inhibition of mitochondrial oxidative damage and apoptosis. DNA-PKcs deficiency sustained kidney function upon LPS stress through normalization of mitochondrial fission/fusion events, mitophagy, and biogenesis. CONCLUSION: We conclude that strategies targeting DNA-PKcs expression or activity may be valuable therapeutic options to prevent or reduce mitochondrial dysfunction and organ damage associated with sepsis-induced MODS.

Mobilization of CD11b+/Ly6chi monocytes causes multi organ dysfunction syndrome in acute pancreatitis.

Objective: Acute pancreatitis (AP) is an inflammatory disorder, the severe form of which is burdened with multi-organ dysfunction and high mortality. The pathogenesis of life -threatening organ complications, such as respiratory and renal failure, is unknown. Design: Organ dysfunction was investigated in a mouse model of AP. The influence of monocytes and neutrophils on multi organ dysfunction syndrome (MODS) was investigated in vivo by antibody depletion. Using real-time-fluorescence and deformability-cytometry (RT-DC) analysis we determined the mechanical properties of neutrophils and monocytes during AP. Furthermore, blood samples of pancreatitis patients were used to characterize severity-dependent chemokine profiles according to the revised Atlanta classification. Results: Similar to AP in humans, severe disease in the mouse model associates with organ dysfunction mainly of lung and kidney, which is triggered by a mobilisation of Ly6g-/CD11b+/Ly6c hi monocytes, but not of Ly6g+/CD11b+ neutrophils. Monocyte depletion by anti-CCR2 antibody treatment ameliorated lung function (oxygen consumption) without interfering with the systemic immune response. RT-DC analysis of circulation monocytes showed a significant increase in cell size during SAP, but without a compensatory increase in elasticity. Patient chemokine profiles show a correlation of AP severity with monocyte attracting chemokines like MCP-1 or MIG and with leukocyte mobilisation. Conclusion: In AP, the physical properties of mobilized monocytes, especially their large size, result in an obstruction of the fine capillary systems of the lung and of the kidney glomeruli. A selective depletion of monocytes may represent a treatment strategy for pancreatitis as well as for other inflammation-related disorders.

A neutrophil-B-cell axis impacts tissue damage control in a mouse model of intraabdominal bacterial infection via Cxcr4.

Sepsis is a life-threatening condition characterized by uncontrolled systemic inflammation and coagulation, leading to multiorgan failure. Therapeutic options to prevent sepsis-associated immunopathology remain scarce. Here, we established a mouse model of long-lasting disease tolerance during severe sepsis, manifested by diminished immunothrombosis and organ damage in spite of a high pathogen burden. We found that both neutrophils and B cells emerged as key regulators of tissue integrity. Enduring changes in the transcriptional profile of neutrophils include upregulated Cxcr4 expression in protected, tolerant hosts. Neutrophil Cxcr4 upregulation required the presence of B cells, suggesting that B cells promoted disease tolerance by improving tissue damage control via the suppression of neutrophils' tissue-damaging properties. Finally, therapeutic administration of a Cxcr4 agonist successfully promoted tissue damage control and prevented liver damage during sepsis. Our findings highlight the importance of a critical B-cell/neutrophil interaction during sepsis and establish neutrophil Cxcr4 activation as a potential means to promote disease tolerance during sepsis.

Dysregulation of neutrophil death in sepsis.

Sepsis is a prevalent disease that has alarmingly high mortality rates and, for several survivors, long-term morbidity. The modern definition of sepsis is an aberrant host response to infection followed by a life-threatening organ dysfunction. Sepsis has a complicated pathophysiology and involves multiple immune and non-immune mediators. It is now believed that in the initial stages of sepsis, excessive immune system activation and cascading inflammation are usually accompanied by immunosuppression. During the pathophysiology of severe sepsis, neutrophils are crucial. Recent researches have demonstrated a clear link between the process of neutrophil cell death and the emergence of organ dysfunction in sepsis. During sepsis, spontaneous apoptosis of neutrophils is inhibited and neutrophils may undergo some other types of cell death. In this review, we describe various types of neutrophil cell death, including necrosis, apoptosis, necroptosis, pyroptosis, NETosis, and autophagy, to reveal their known effects in the development and progression of sepsis. However, the exact role and mechanisms of neutrophil cell death in sepsis have not been fully elucidated, and this remains a major challenge for future neutrophil research. We hope that this review will provide hints for researches regarding neutrophil cell death in sepsis and provide insights for clinical practitioners.

Expression of MicroRNAs in Sepsis-Related Organ Dysfunction: A Systematic Review.

Sepsis is a critical condition characterized by increased levels of pro-inflammatory cytokines and proliferating cells such as neutrophils and macrophages in response to microbial pathogens. Such processes lead to an abnormal inflammatory response and multi-organ failure. MicroRNAs (miRNA) are single-stranded non-coding RNAs with the function of gene regulation. This means that miRNAs are involved in multiple intracellular pathways and thus contribute to or inhibit inflammation. As a result, their variable expression in different tissues and organs may play a key role in regulating the pathophysiological events of sepsis. Thanks to this property, miRNAs may serve as potential diagnostic and prognostic biomarkers in such life-threatening events. In this narrative review, we collect the results of recent studies on the expression of miRNAs in heart, blood, lung, liver, brain, and kidney during sepsis and the molecular processes in which they are involved. In reviewing the literature, we find at least 122 miRNAs and signaling pathways involved in sepsis-related organ dysfunction. This may help clinicians to detect, prevent, and treat sepsis-related organ failures early, although further studies are needed to deepen the knowledge of their potential contribution.