Update on Neutrophil Function in Severe Inflammation

Biological characteristics of manganese transporter MntP in Klebsiella pneumoniae

Klebsiella pneumoniae is an important opportunistic pathogen that causes a variety of infections. It is critical for bacteria to maintain metal homeostasis during infection. By using an isogenic mntP deletion mutant of K. pneumoniae strain NTUH-K2044, we found that MntP was a manganese efflux pump. Manganese increased the tolerance to oxidative stress, and oxidative stress could increase the intracellular manganese concentration. In oxidative stress, the mntP deletion mutant exhibited significantly higher sensitivity to manganese. Furthermore, iron could increase the tolerance of the mntP deletion mutant to manganese. Inductively coupled plasma mass spectrometry analysis revealed that the mntP deletion mutant had higher intracellular manganese and iron concentrations than wild-type and complementary strains. These findings suggested that iron could increase manganese tolerance in K. pneumoniae. This work elucidated the role of MntP in manganese detoxification and Mn/Fe homeostasis in K. pneumoniae.IMPORTANCEMetal homeostasis plays an important role during the process of bacterial infection. Herein, we revealed that MntP was involved in intracellular manganese homeostasis. Manganese promoted resistance to oxidative stress in Klebsiella pneumoniae. Furthermore, we demonstrated that the mntP deletion mutant exhibited significantly lower survival under manganese and H2O2 conditions. Oxidative stress increased the intracellular manganese content of the mntP deletion mutant. MntP played a critical role in maintaining intracellular manganese and iron concentrations. MntP contributed to manganese detoxification and Mn/Fe homeostasis in K. pneumoniae.

Navigating the Modern Landscape of Sepsis: Advances in Diagnosis and Treatment

Sepsis poses a significant threat to human health due to its high morbidity and mortality rates worldwide. Traditional diagnostic methods for identifying sepsis or its causative organisms are time-consuming and contribute to a high mortality rate. Biomarkers have been developed to overcome these limitations and are currently used for sepsis diagnosis, prognosis prediction, and treatment response assessment. Over the past few decades, more than 250 biomarkers have been identified, a few of which have been used in clinical decision-making. Consistent with the limitations of diagnosing sepsis, there is currently no specific treatment for sepsis. Currently, the general treatment for sepsis is conservative and includes timely antibiotic use and hemodynamic support. When planning sepsis-specific treatment, it is important to select the most suitable patient, considering the heterogeneous nature of sepsis. This comprehensive review summarizes current and evolving biomarkers and therapeutic approaches for sepsis.

Cytotoxic Oxidative Stress Effects of Neutrophil Extracellular Traps' Components on Cattle Spermatozoa

Bovine spermatozoa are highly susceptible to oxidative stress (OS), and it is known to affect their cellular functions. The main leukocyte producers of reactive oxygen species (ROS) in mammalian semen are polymorphonuclear neutrophils (PMN). PMN activation can result in the formation of neutrophil extracellular traps (NETs), which have been shown to affect the motility and function of spermatozoa. However, OS effects on bull spermatozoa derived from individual NETs components have not been investigated. The hypothesis of this study was that specific NETs components might generate OS on bull spermatozoa. Bovine sperm cells were incubated with five NETs-associated molecules, including 30 μg/mL histone 2A (H2A), neutrophil elastase (NE), 1 μg/mL myeloperoxidase (MPO), cathepsin G (Cat-G), and cathelicidin LL37 (LL-37), for a time course ranging from 15 to 240 min. Fluorescence microscopy was used to evaluate the coincubation of bovine PMN and sperm cells. Within 15 min, H2A, NE, and LL-37 caused membrane disruption, while MPO and Cat-G caused OS on bull spermatozoa after 1 h of coincubation. NET formation was observed within 15 min of coincubation in co-cultures of bovine PMN/sperm cells. This study is the first to report on the role of cytotoxic OS effects caused by NETs-derived components in bovine sperm in vitro.

Cell-free DNA kinetics in response to muscle-damaging exercise: A drop jump study

A significant increase in circulating cell-free DNA (cfDNA) occurs with physical exercise, which depends on the type of exertion and the duration. The aims of this study were as follows: (1) to investigate the time course of cfDNA and conventional markers of muscle damage from immediately after to 96 h after muscle-damaging exercise; and (2) to investigate the relationship between cfDNA and indicators of primary (low-frequency fatigue and maximal voluntary isometric contraction) and secondary (creatine kinase and delayed-onset muscle soreness) muscle damage in young healthy males. Fourteen participants (age, 22 ± 2 years; weight, 84.4 ± 11.2 kg; height, 184.0 ± 7.4 cm) performed 50 intermittent drop jumps at 20 s intervals. We measured cfDNA and creatine kinase concentrations, maximal voluntary isometric contraction torque, low-frequency fatigue and delayed-onset muscle soreness before and at several time points up to 96 h after exercise. Plasma cfDNA levels increased from immediately postexercise until 72 h postexercise (P < 0.01). Elevation of postexercise cfDNA was correlated with both more pronounced low-frequency fatigue (r = -0.52, P = 3.4 × 10-11) and delayed-onset muscle soreness (r = 0.32, P = 0.00019). Levels of cfDNA change in response to severe primary and secondary muscle damage after exercise. Levels of cfDNA exhibit a stronger correlation with variables related to primary muscle damage than to secondary muscle damage, suggesting that cfDNA is a more sensitive marker of acute loss of muscle function than of secondary inflammation or damaged muscle fibres.

Non-viral vector-based genome editing for cancer immunotherapy

Despite the exciting promise of cancer immunotherapy in the clinic, immune checkpoint blockade therapy and T cell-based therapies are often associated with low response rates, intrinsic and adaptive immune resistance, and systemic side effects. CRISPR-Cas-based genome editing appears to be an effective strategy to overcome these unmet clinical needs. As a safer delivery platform for the CRISPR-Cas system, non-viral nanoformulations have been recently explored to target tumor cells and immune cells, aiming to improve cancer immunotherapy on a gene level. In this review, we summarized the efforts of non-viral vector-based CRISPR-Cas-mediated genome editing in tumor cells and immune cells for cancer immunotherapy. Their design rationale and specific applications were highlighted.

Exploring Immune Redox Modulation in Bacterial Infections: Insights into Thioredoxin-Mediated Interactions and Implications for Understanding Host-Pathogen Dynamics

Bacterial infections trigger a multifaceted interplay between inflammatory mediators and redox regulation. Recently, accumulating evidence has shown that redox signaling plays a significant role in immune initiation and subsequent immune cell functions. This review addresses the crucial role of the thioredoxin (Trx) system in the initiation of immune reactions and regulation of inflammatory responses during bacterial infections. Downstream signaling pathways in various immune cells involve thiol-dependent redox regulation, highlighting the pivotal roles of thiol redox systems in defense mechanisms. Conversely, the survival and virulence of pathogenic bacteria are enhanced by their ability to counteract oxidative stress and immune attacks. This is achieved through the reduction of oxidized proteins and the modulation of redox-sensitive signaling pathways, which are functions of the Trx system, thereby fortifying bacterial resistance. Moreover, some selenium/sulfur-containing compounds could potentially be developed into targeted therapeutic interventions for pathogenic bacteria. Taken together, the Trx system is a key player in redox regulation during bacterial infection, and contributes to host-pathogen interactions, offering valuable insights for future research and therapeutic development.

Vaginal Microbiota and Proinflammatory Status in Patients with Polycystic Ovary Syndrome: An Exploratory Study

Background/Purpose: Polycystic ovary syndrome (PCOS) is an endocrine-metabolic disease most common in patients of childbearing age. This pathology is associated with clinical, metabolic, and reproductive complications. We evaluated the diversity of the vaginal microbiota (VM), the vaginal inflammatory reaction (VIR), the proinflammatory state, and the activation of polymorphonuclear neutrophils (PMN) with the production of neutrophil extracellular traps (NETs). Methods: Thirty-three patients who attended a consultation at the Hospital UTPL-Santa Inés, Loja, Ecuador, from May to August 2023 who were diagnosed with PCOS participated in this study. Blood samples, vaginal discharge, and a survey were obtained. Results: A high number of patients, 23/33 (69.7%), presented altered microbiota in clinical variables associated with PCOS phenotypes A and B, sexual partners (>2), and oligomenorrhoea. A significant statistical association was only observed for sexually transmitted infections at sampling (p = 0.023) and insulin (p = 0.002). All eight cases studied with VIR had PMN/NETotic activity. A high frequency of proinflammatory states was observed in all vaginal microbiota states. Conclusions: These results suggest that the PCOS could trigger a proinflammatory state in the vaginal epithelium independently of the state of the vaginal microbiota. Furthermore, the presence of NETs observed in the cases studied could decrease fertility in these PCOS patients.

Association of Neutrophil-to-Lymphocyte Ratio With All-Cause Mortality in the Elderly Population in China: A Retrospective Cohort Study

Neutrophil-to-lymphocyte ratio (NLR) is an emerging systemic inflammation marker associated with disease progression and mortality in patients. However, there is limited research on the predictive value of NLR in the general population. This study aimed to investigate the relationship between NLR and all-cause mortality in an elderly Chinese population. A retrospective cohort study was conducted based on health examination in a community in Shanghai, China, between 2015 and 2020. Among 6364 participants (aged ≥ 55 years), a total of 169 (2.66%) participants died during a median follow-up period of 5.37 years. The median NLR was 1.63 (interquartile range: 1.29, 2.11). Multivariate analysis revealed that the upper 2 quartiles of NLR were positively associated with all-cause mortality (Q3 vs Q1: hazard ratio [HR] = 1.82, 95% confidence interval [CI]: 1.07-3.09; Q4 vs Q1: HR = 2.22, 95% CI: 1.34-3.68, P for trend <.001). The stratified and interaction analyses showed that age, sex, body mass index (BMI), history of diabetes, or history of hypertension did not significantly modify the association between NLR and all-cause mortality. Elevated NLR was independently associated with an increased risk of all-cause mortality in the elderly Chinese population.

Narrative Review of Biological Markers in Chronic Limb-Threatening Ischemia

BACKGROUND

Chronic limb-threatening ischemia (CLTI), the advanced stage of peripheral arterial disease, is diagnosed in the presence of ischemic rest pain, non-healing ulcers, or gangrene. Several studies have demonstrated that inflammation and endothelial dysfunction are some of the main substrates of CLTI.

METHODS

A narrative review was conducted and reported according to PRISMA guidelines. Three databases were searched-Web of Science, Medline, and EMBASE-for the studies assessing CLTI and the biological markers related to it.

RESULTS

We included 22 studies, and all the markers identified (C-reactive protein, D-dimers, fibrinogen, cytokines, IL-6, TNF-α, ICAM-1 (Intracellular Adhesion Molecule-1), VCAM-1 (Vascular Cell Adhesion Molecule-1), neutrophile-to-lymphocytes ratio (NLR), IL-8, Pentraxin-3, neutrophil gelatinase-associated lipocalin (NGAL), calprotectin, E-selectin, P-selectin, neopterin, High-Mobility Group Box-1 protein (HGMB-1), Osteoprotegerin (OPG) and Sortilin) were positively associated with advanced CLTI, with major limb or major cardiovascular events in these patients.

CONCLUSIONS

All the studied markers had increased values in patients with CLTI, especially when associated with diabetes mellitus, proving a very important association between diabetes and major limb or cardiovascular events in these patients. There is a need for more studies to validate these markers in terms of diagnosis or prognosis in CLTI patients and in trying to find new medical strategies that target inflammation or endothelial dysfunction in these patients.

Effector function and neutrophil cell death in the severity of sepsis with diabetes mellitus

Sepsis, a life-threatening condition resulting from immune dysregulation, is typically triggered by bacterial infections and commonly coexists with diabetes mellitus. Neutrophils are the first responders to infection and require regulated activation to control pathogen and damage-associated molecular patterns. Dysregulation of neutrophil activation leads to uncontrolled inflammatory responses, often observed in both sepsis and diabetes patients. Neutrophil dysregulation, characterized by effector dysfunction and inadequate cell death processes, can serve as a biomarker for assessing sepsis severity, particularly in diabetic patients. This review provides information on the relationship between effector function, neutrophil cell death, and the severity of sepsis in individuals with diabetes mellitus, aiming to shed light on the mechanisms underlying sepsis progression. Topics covered in the review include an overview of effector function of neutrophil cells, mechanisms of neutrophil cell death, and dysregulation of effectors and neutrophil cell death processes in sepsis severity with diabetes mellitus.

Age-associated accumulation of B cells promotes macrophage inflammation and inhibits lipolysis in adipose tissue during sepsis

Non-canonical lipolysis induced by inflammatory cytokines or Toll-like receptor ligands is required for the regulation of inflammation during endotoxemia and sepsis. Canonical lipolysis induced by catecholamines declines during aging due to factors including an expansion of lymphocytes, pro-inflammatory macrophage polarization, and an increase in chronic low-grade inflammation; however, the extent to which the non-canonical pathway of lipolysis is active and impacted by immune cells during aging remains unclear. Therefore, we aimed to define the extent to which immune cells from old mice influence non-canonical lipolysis during sepsis. We identified age-associated impairments of non-canonical lipolysis and an accumulation of dysfunctional B1 B cells in the visceral white adipose tissue (vWAT) of old mice. Lifelong deficiency of B cells results in restored non-canonical lipolysis and reductions in pro-inflammatory macrophage populations. Our study suggests that targeting the B cell-macrophage signaling axis may resolve metabolic dysfunction in aged vWAT and attenuate septic severity in older individuals.

CD64 plays a key role in diabetic wound healing

Introduction

Wound healing poses a clinical challenge in diabetes mellitus (DM) due to compromised host immunity. CD64, an IgG-binding Fcgr1 receptor, acts as a pro-inflammatory mediator. While its presence has been identified in various inflammatory diseases, its specific role in wound healing, especially in DM, remains unclear.

Objectives

We aimed to investigate the involvement of CD64 in diabetic wound healing using a DM animal model with CD64 KO mice.

Methods

First, we compared CD64 expression in chronic skin ulcers from human DM and non-DM skin. Then, we monitored wound healing in a DM mouse model over 10 days, with or without CD64 KO, using macroscopic and microscopic observations, as well as immunohistochemistry.

Results

CD64 expression was significantly upregulated (1.25-fold) in chronic ulcerative skin from DM patients compared to non-DM individuals. Clinical observations were consistent with animal model findings, showing a significant delay in wound healing, particularly by day 7, in CD64 KO mice compared to WT mice. Additionally, infiltrating CD163+ M2 macrophages in the wounds of DM mice decreased significantly compared to non-DM mice over time. Delayed wound healing in DM CD64 KO mice correlated with the presence of inflammatory mediators.

Conclusion

CD64 seems to play a crucial role in wound healing, especially in DM conditions, where it is associated with CD163+ M2 macrophage infiltration. These data suggest that CD64 relies on host immunity during the wound healing process. Such data may provide useful information for both basic scientists and clinicians to deal with diabetic chronic wound healing.

Biocompatibility assessment of bovine serum albumin conjugated manganese dioxide nanoparticle and their therapeutic role against microwave radiation induced haematological toxicity in male Wistar rats

Microwave (MW) radiations are widely used in communications, radar and medical treatment and thus human exposure to MW radiations have increased tremendously, raising health concerns as MW has been implicated in induction of oxidative stress condition in our body. Few metallic nanoparticles (NPs) have been shown to mimic the activity of antioxidant enzymes and hence can be applied for the modulation of adverse effects caused by MW. Present study aimed to assess the biocompatibility of Bovine serum albumin (BSA) conjugated manganese dioxide nanoparticles (MNP*) and to counteract the impact of MW on the haematological system of male Wistar rats. Experiments were conducted in two sets. Set I involved biodistribution and antioxidant activity evaluation of MNP* at different doses. Results showed a dose-dependent increase in antioxidant potential and significant biodistribution in the liver, spleen, kidney, and testis, with no organ damage, indicating its biocompatibility. Experiment set II constituted the study of separate and combined effects of MW and MNP* on haematological parameters, oxidative status, and genotoxic study in the blood of rats. MW exposure significantly altered red blood cell count, hemoglobin, packed cell volume percentage, monocyte percentage, aspartate aminotransferase, Alanine aminotransferase and uric acid. MW also induced significant DNA damage in the blood. A significant increase in lipid peroxidation and a decrease in antioxidant enzyme superoxide dismutase was also observed in MW exposed group. However, these alterations were reduced significantly when MNP* was administered. Thus, MNP* showed biocompatibility and modulatory effects against MW-induced alterations in the haematological system of rats.

Blood neutrophil to lymphocyte ratio is associated with 90-day mortality and 60-day readmission in Gram negative bacteremia: a multi-center cohort study

INTRODUCTION

The Neutrophil-Lymphocyte Ratio (NLR) in blood has demonstrated its capability to predict bacteremia in emergency departments, and its association with mortality has been established in patients with sepsis in intensive care units. However, its potential concerning mortality and readmission in patients with Gram-negative bacteremia (GNB) is unexplored.

METHODS

This retrospective cohort study included patients with GNB between 2018 and 2022 from six hospitals in the Capital Region of Denmark. Patients who were immunosuppressed or had missing NLR values on the day of blood culture were excluded. Logistic regression models were used to analyze the association between NLR levels and 90-day all-cause mortality, while the logit link interpretation of the cumulative incidence function was used to assess the association between NLR levels and 60-day readmission. Associations were quantified as odds ratios (OR) with corresponding 95% confidence intervals (CI).

RESULTS

The study included 1763 patients with a median age was 76.8 years and 51.3% were female. The median NLR was 17.3 and 15.8% of patients had a quick sequential organ failure assessment score of two or three. Urinary tract infection (UTI) was the most frequent focus and Escherichia coli the most frequent pathogen. Statistically significant differences in median NLR were found by age group and pathogen, and for patients with or without hypertension, liver disease, chronic obstructive pulmonary disease, dementia, and alcohol abuse. 378 patients (21.4%) died before 90 days. 526 (29.8%) patients were readmitted to the hospital within 60 days. For each doubling of the NLR, the OR for all-cause 90-day mortality was 1.15 (95% CI, 1.04-1.27) and 1.12 (95% CI, 1.02-1.24) for 60-day readmission. Analysis of subgroups did not show statistically significant differences between groups in relation to the association between NLR and mortality. The discriminatory ability of NLR for mortality was limited and comparable to blood neutrophil or lymphocyte count, producing receiver operating characteristic curves with an area under the curve of 0.59 (95% CI, 0.56-0.63), 0.60 (95% CI, 0.56-0.65) and 0.53 (95% CI, 0.49-0.56), respectively.

CONCLUSION

Blood neutrophil-lymphocyte ratio was associated with 90-day all-cause mortality and 60-day readmission in patients with GNB. However, the ratio has limited ability in predicting mortality or readmission.

Whole blood transcriptomics reveals granulocyte colony-stimulating factor as a mediator of cardiopulmonary bypass-induced systemic inflammatory response syndrome

Objectives

Systemic inflammatory response syndrome (SIRS) is a frequent complication of cardiopulmonary bypass (CPB). SIRS is associated with significant morbidity and mortality, but its pathogenesis remains incompletely understood, and as a result, biomarkers are lacking and treatment remains expectant and supportive. This study aimed to understand the pathophysiological mechanisms driving SIRS induced by CPB and identify novel therapeutic targets that might reduce systemic inflammation and improve patient outcomes.

Methods

Twenty-one patients undergoing cardiac surgery and CPB were recruited, and blood was sampled before, during and after surgery. SIRS was defined using the American College of Chest Physicians/Society of Critical Care Medicine criteria. We performed immune cell profiling and whole blood transcriptomics and measured individual mediators in plasma/serum to characterise SIRS induced by CPB.

Results

Nineteen patients fulfilled criteria for SIRS, with a mean duration of 2.7 days. Neutrophil numbers rose rapidly with CPB and remained elevated for at least 48 h afterwards. Transcriptional signatures associated with neutrophil activation and degranulation were enriched during CPB. We identified a network of cytokines governing these transcriptional changes, including granulocyte colony-stimulating factor (G-CSF), a regulator of neutrophil production and function.

Conclusions

We identified neutrophils and G-CSF as major regulators of CPB-induced systemic inflammation. Short-term targeting of G-CSF could provide a novel therapeutic strategy to limit neutrophil-mediated inflammation and tissue damage in SIRS induced by CPB.

Neutrophil extracellular traps in bacterial infections and evasion strategies

Neutrophils are innate immune cells that have a vital role in host defense systems. Neutrophil extracellular traps (NETs) are one of neutrophils' defense mechanisms against pathogens. NETs comprise an ejected lattice of chromatin associated with histones, granular proteins, and cytosolic proteins. They are thought to be an efficient strategy to capture and/or kill bacteria and received intensive research interest in the recent years. However, soon after NETs were identified, it was observed that certain bacteria were able to evade NET entrapment through many different mechanisms. Here, we outline the recent progress of NETs in bacterial infections and the strategies employed by bacteria to evade or withstand NETs. Identifying the molecules and mechanisms that modulate NET release will improve our understanding of the functions of NETs in infections and provide new avenues for the prevention and treatment of bacterial diseases.

A living neutrophil Biorobot synergistically blocks multifaceted inflammatory pathways in macrophages to effectively neutralize cytokine storm

Cytokine storm is a potentially life-threatening immune response typically correlated with lung injury, particularly in people with underlying disease states, such as pneumonia. Therefore, the prompt treatment of cytokine storm is essential for successful recovery from a potentially fatal condition. Herein, a living anti-inflammatory Biorobot (firefighter), composed of neutrophils encapsulating mannose-decorated liposomes of the NF-κB inhibitor TPCA-1 and STING inhibitor H-151 (M-Lip@TH, inflammatory retardant), is developed for alleviating hyperinflammatory cytokine storm through targeting multiple inflammatory pathways in macrophages. Biorobot fully inherits the chemotaxis characteristics of neutrophils, and efficiently delivers and releases therapeutic M-Lip@TH at the inflammatory site. Subsequently, M-Lip@TH selectively targets macrophages and simultaneously blocks the transcription factor NF-κB pathway and STING pathway, thereby preventing the overproduction of cytokines. Animal studies show that Biorobot selectively targets LPS-induced acute lung injury, and not only inhibits the NF-κB pathway to suppress the release of various pro-inflammatory cytokines and chemokines, but also blocks the STING pathway to prevent an overactive immune response, which helps to neutralize cytokine storms. Particularly, Biorobot reduces lung inflammation and injury, improves lung function, and increases the survival rates of pneumonia mice. Therefore, Biorobot represents a rational combination therapy against cytokine storm, and may provide insights into the treatment of diseases involving overactive immune responses.

Assessing the predictive value of neutrophil percentage to albumin ratio for ICU admission in ischemic stroke patients

Background

Acute ischemic stroke (AIS) remains a substantial global health challenge, contributing to increased morbidity, disability, and mortality. This study aimed at investigating the predictive value of the neutrophil percentage to albumin ratio (NPAR) in determining intensive care unit (ICU) admission among AIS patients.

Methods

A retrospective observational study was conducted, involving AIS cases admitted to a tertiary hospital in Jordan between 2015 and 2020. Lab data were collected upon admission, and the primary outcome was ICU admission during hospitalization. Descriptive and inferential analyses were performed using SPSS version 29.

Results

In this study involving 364 AIS patients, a subset of 77 (21.2%) required admission to the ICU during their hospital stay, most frequently within the first week of admission. Univariable analysis revealed significantly higher NPAR levels in ICU-admitted ischemic stroke patients compared to those who were not admitted (23.3 vs. 15.7, p < 0.001), and multivariable regression models confirmed that higher NPAR (≥19.107) independently predicted ICU admission in ischemic stroke patients (adjusted odds ratio [aOR] = 4.85, 95% CI: 1.83-12.83). Additionally, lower GCS scores and higher neutrophil-to-lymphocyte ratio (NLR) were also associated with increased likelihood of ICU admission. In terms of predictive performance, NPAR showed the highest accuracy with an AUC of 0.885, sensitivity of 0.805, and specificity of 0.854, using a cutoff value of 19.107. NPAR exhibits an AUC of 0.058, significantly outperforming NLR (Z = 2.782, p = 0.005).

Conclusion

NPAR emerged as a robust independent predictor of ICU admission in ischemic stroke patients, surpassing the predictive performance of the NLR.

Anti-inflammatory potential of a Thai traditional remedy called Prabchompoothaweep in an animal model of acute and sub-acute inflammation

ETHNOPHARMACOLOGICAL RELEVANCE

Prabchompoothaweep (PCT) is a Thai remedy which is composed of 23 herbs and has been added onto the National List of Essential Medicines (NLEM) of Thailand. This remedy has been used to treat allergic rhinitis and asthma in Thai traditional medicine for many years. Furthermore, a few studies have reported anti-allergic, anti-malarial, anti-inflammatory and antioxidant activities.

AIM OF THE STUDY

This study aims to evaluate anti-inflammatory activity of PCT extract in an animal model.

MATERIALS AND METHODS

The animal model of acute inflammation was studied over a 24-h period, utilizing the method of carrageenan-induced paw oedema. In addition, sub-acute inflammation was examined over 7 days, using the formalin-induced paw oedema method. The treatment groups received PCT extracts, via the oral route, at 1-h prior to injection and then the sub plantar of the rat right paw was injected with the named substances to generate paw oedema. The paw thickness was measured by vernier caliper at regular intervals after injection. At the end of experiment, the blood and paw tissues were collected for measurement of pro-inflammatory cytokines and histological examination respectively.

RESULTS

In acute inflammation, all doses of PCT extract (250, 500 and 1000 mg/kg p.o.) significantly reduced paw thickness after the first 3 h in a dose-dependent manner and the percentage of inhibition was 38.7%, 47.8% and 49.5% respectively. The pro-inflammatory cytokines, including TNF-α and IL-1β, statistically decreased with all doses of the extracts. However, the histological examination did not reveal significant results due to the short time duration. As regards to sub-acute inflammation, all doses of PCT extract significantly reduced paw thickness with 12.78%, 23.64% and 35.78%, in a dose dependent manner. Also, the pro-inflammatory cytokines (TNF-α and IL-1β) significantly decreased at day 7. Interestingly, the histological examination of paw tissue demonstrated reductions of mononuclear infiltrations of inflammatory cells, this was observed in the group receiving PCT extracts, also in a dose-dependent manner.

CONCLUSION

Therefore, PCT exerted anti-inflammatory activity in an animal model of acute and sub-acute inflammation, suggesting that it could be used as a new source for treatment of inflammatory diseases.

The neutropenic diet: Are well-cooked vegetables still good sources of nutrients? A mini-narrative review

A low immune response is fatal for humans because increased infection risk is related to both morbidity and mortality. The neutropenic diet is applied if a person's neutrophil count is <2000 cells/μL. When compared with standard nutrition treatment, the neutropenic diet is found to be related to deficiencies in dietary fiber, vitamins C, A, and D, magnesium, and calcium. This is also related to malnutrition in patients diagnosed with cancer. Although raw vegetables are good sources of these nutrients, they can also be sources of pathogen microorganisms. Thus, the consumption of well-cooked vegetables is an essential principle in the neutropenic diet. Although many cooking methods are available, pressure cooking is the most commonly used in neutropenic diet kitchens to reduce pathogen transmission risk. According to many studies, the cooking process is associated with significant nutrient loss. In particular, boiling is found to be related to losses in vitamins C, A, and K, phenolic compounds, flavonoids, calcium, zinc, manganese, magnesium, copper, and iron in different types of vegetables. Even though some studies have shown that standard nutrition treatment with the adoption of food safety guidelines does not increase infection risk and the neutropenic diet is related to malnutrition, no guidelines have thus far suggested the application of standard nutrition treatment in neutropenic patients. Consequently, additional studies are required to compare the beneficial and harmful effects of the neutropenic diet to a standard nutrition treatment and support the application of standard nutrition treatment with the adoption of food safety guidelines at least in mildly neutropenic patients.

Ethyl Lithospermate Reduces Lipopolysaccharide-Induced Inflammation through Inhibiting NF-κB and STAT3 Pathways in RAW 264.7 Cells and Zebrafish

OBJECTIVE

To explore the anti-inflammatory effects of ethyl lithospermate in lipopolysaccharide (LPS)-stimulated RAW 264.7 murine-derived macrophages and zebrafish, and its underlying mechanisms.

METHODS

3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazoliumbromide (MTT) assays were performed to investigate the toxicity of ethyl lithospermate at different concentrations (12.5-100 µ mol/L) in RAW 264.7 cells. The cells were stimulated with LPS (100 ng/mL) for 12 h to establish an inflammation model in vitro, the production of pro-inflammatory cytokines interleukin (IL)-6 and tumor necrosis factor α (TNF-α) were assessed by enzyme linked immunosorbent assay (ELISA). Western blot was used to ascertain the protein expressions of signal transducer and activator of transcription 3 (STAT3), nuclear factor kappa B (NF-κB) p65, phospho-STAT3 (p-STAT3, Tyr705), inhibitor of NF-κB (IκB) α, and phospho-I κB α (p-IκB α, Ser32), and confocal imaging was used to identify the nuclear translocation of NF-κB p65 and p-STAT3 (Tyr705). Additionally, the yolk sacs of zebrafish (3 days post fertilization) were injected with 2 nL LPS (0.5 mg/mL) to induce an inflammation model in vivo. Survival analysis, hematoxylin-eosin (HE) staining, observation of neutrophil migration, and quantitative real-time polymerase chain reaction (qRT-PCR) were used to further study the anti-inflammatory effects of ethyl lithospermate and its probable mechanisms in vivo.

RESULTS

The non-toxic concentrations of ethyl lithospermate have been found to range from 12.5 to 100 µ mol/L. Ethyl lithospermate inhibited the release of IL-6 and TNF-α(P<0.05 or P<0.01), decreased IκBα degradation and phosphorylation (P<0.05) as well as the nuclear translocation of NF-κB p65 and p-STAT3 (Tyr705) in LPS-induced RAW 264.7 cells (P<0.01). Ethyl lithospermate also decreased inflammatory cells infiltration and neutrophil migration while increasing the survival rate of LPS-stimulated zebrafish (P<0.05 or P<0.01). In addition, ethyl lithospermate also inhibited the mRNA expression levels of of IL-6, TNF-α, IκBα, STAT3, and NF-κB in LPS-stimulated zebrafish (P<0.01).

CONCLUSION

Ethyl lithospermate exerts anti-Inflammatory effected by inhibiting the NF-κB and STAT3 signal pathways in RAW 264.7 macrophages and zebrafish.

Recent advances in the role of neutrophils and neutrophil extracellular traps in acute pancreatitis

Pancreatitis is an inflammatory disease, which is triggered by adverse events in acinar cells of the pancreas. After the initial injury, infiltration of neutrophils in pancreas is observed. In the initial stages of pancreatitis, the inflammation is sterile. It has been shown that the presence of neutrophils at the injury site can modulate the disease. Their depletion in experimental animal models of the acute pancreatitis has been shown to be protective. But information on mechanism of contribution to inflammation by neutrophils at the injury site is not clear. Once at injury site, activated neutrophils release azurophilic granules containing proteolytic enzymes and generate hypochlorous acid which is a strong microbicidal agent. Additionally, emerging evidence shows that neutrophil extracellular traps (NETs) are formed which consist of decondensed DNA decorated with histones, proteases and granular and cytosolic proteins. NETs are considered mechanical traps for microbes, but there is preliminary evidence to indicate that NETs, which constitute a special mechanism of the neutrophil defence system, play an adverse role in pancreatitis by contributing to the pancreatic inflammation and distant organ injury. This review presents the overall current information about neutrophils and their role including NETs in acute pancreatitis (AP). It also highlights current gaps in knowledge which should be explored to fully elucidate the role of neutrophils in AP and for therapeutic gains.

The Clinical Performance of Cell Population Data for Diagnosis of Bloodstream Infection in Cancer Patients

Background Bloodstream infection (BSI) induces a change in the number and morphology of blood cells. In this study, we compared cell population data (CPD) parameters between cancer patients with or without BSI to determine whether these parameters could serve as biomarkers of BSI. Methods Between April and June 2021, 43 BSI-negative and 22 BSI-positive cancer patients were enrolled in this study. We compared 18 CPD parameters and biomarkers between cancer patients with BSI-positive and BSI-negative. Results There were significant differences in the levels of several CPD parameters, including MO-WZ (p=0.040), MO-X (p<0.01), MO-Y (p=0.012), NE-SFL (p<0.01), and NE-WX (p=0.037), but not C-reactive protein (p=0.347) and procalcitonin (p=0.237) between BSI-positive and BSI-negative patients. The areas under the receiver-operating characteristic curves (AUCs) were above 0.7 for MO-X (0.762; 95% confidence intervals (CI): 0.624-0.901), NE-SFL (0.766; 95% CI: 0.625-0.880). And LY-WY (p=0.024) showed a significant difference between gram-negative and gram-positive BSI patients with high AUC (0.883; 95% CI: 0.703-1). Conclusion CPD parameters (MO-X and NE-SFL) provide additional information for discriminating between BSI-negative and BSI-positive BSI. And LY-WY provides useful information for discriminating between cancer patients with gram-negative BSI and gram-positive BSI.

The Diagnostic, Therapeutic and Prognostic Relevance of Neutrophil Extracellular Traps in Polytrauma

Neutrophil extracellular traps (NETs) represent a recently discovered polymorphonuclear leukocyte-associated ancient defence mechanism, and they have also been identified as part of polytrauma patients' sterile inflammatory response. This systematic review aimed to determine the clinical significance of NETs in polytrauma, focusing on potential prognostic, diagnostic and therapeutic relevance. The methodology covered all major databases and all study types, but was restricted to polytraumatised humans. Fourteen studies met the inclusion criteria, reporting on 1967 patients. Ten samples were taken from plasma and four from whole blood. There was no standardisation of methodology of NET detection among plasma studies; however, of all the papers that included a healthy control NET, proxies were increased. Polytrauma patients were consistently reported to have higher concentrations of NET markers in peripheral blood than those in healthy controls, but their diagnostic, therapeutic and prognostic utility is equivocal due to the diverse study population and methodology. After 20 years since the discovery of NETs, their natural history and potential clinical utility in polytrauma is undetermined, requiring further standardisation and research.

Effect of different sperm populations on neutrophils extracellular traps (NETs) formation in cattle

In cattle, clinical and subclinical inflammation in the bovine female reproductive tract (FRT) significantly reduces fertility. PMN participate in this FRT-associated inflammation by eliminating pathogens by eliciting various defense mechanisms, with the release of neutrophil extracellular traps NETs) being the latest process discovered. Consistently, human-, bovine- and porcine-derived spermatozoa induce release of NETs in exposed PMN of the same species origin, and thereby decreasing sperm motility through NETs-mediated entrapment. The release of NETs in the presence of different sperm sub-populations is evaluated in this work. Cryopreserved bovine sperm were selected and different sperm populations were used: viable sperm, sperm with oxidative stress, capacitated sperm, and sperm with loss of viability. Isolated PMN of dairy cows were co-incubated with these sperm populations for 4 h. Neutrophil elastase (NE) and DNA were detected by fluorescence microscopy analysis. It was noted that exposed bovine PMN released NETs in the presence of sperm. Moreover, sperm-triggered NETosis resulted different phenotypes of NETs, i. e. spread NETs (sprNETs), diffused NETs (diffNETs) and aggregated NETs (aggNETs). Viable/motile spermatozoa induced a higher proportion of NETotic cells at 15, 60 and 120 min in comparison to controls. In conclusion, all bovine sperm populations in co-culture with PMN generated NETs extrusion while viable sperm activated NETotic cells to a greater extent. With this being an early event in the activation of bovine PMN.

Rethinking neutrophil extracellular traps

Neutrophils are a major subset of leukocytes in human circulating blood. In some circumstances, neutrophils release neutrophil extracellular traps (NETs). lnitially, NETs were considered to have a strong antibacterial capacity. However, currently, NETs have been shown to have a pivotal impact on various diseases. Different stimulators induce the production of different types of NETs, and their biological functions and modes of clearance do not appear to be the same. In this review, we will discuss several important issues related to NETs in order to better understand the relationship between NETs and diseases, as well as how to utilize the characteristics of NETs for disease treatment.

Role of Neutrophil Extracellular Traps in Health and Disease Pathophysiology: Recent Insights and Advances

Neutrophils are the principal trouper of the innate immune system. Activated neutrophils undergo a noble cell death termed NETosis and release a mesh-like structure called neutrophil extracellular traps (NETs) as a part of their defensive strategy against microbial pathogen attack. This web-like architecture includes a DNA backbone embedded with antimicrobial proteins like myeloperoxidase (MPO), neutrophil elastase (NE), histones and deploys in the entrapment and clearance of encountered pathogens. Thus NETs play an inevitable beneficial role in the host's protection. However, recent accumulated evidence shows that dysregulated and enhanced NET formation has various pathological aspects including the promotion of sepsis, pulmonary, cardiovascular, hepatic, nephrological, thrombotic, autoimmune, pregnancy, and cancer diseases, and the list is increasing gradually. In this review, we summarize the NET-mediated pathophysiology of different diseases and focus on some updated potential therapeutic approaches against NETs.

Cytomegalovirus durably primes neutrophil oxidative burst

Cytomegalovirus (CMV) is a ubiquitous herpes virus that infects most humans, thereafter persisting lifelong in tissues of the host. It is a known pathogen in immunosuppressed patients, but its impact on immunocompetent hosts remains less understood. Recent data have shown that CMV leaves a significant and long-lasting imprint in host immunity that may confer some protection against subsequent bacterial infection. Such innate immune activation may come at a cost, however, with potential to cause immunopathology. Neutrophils are central to many models of immunopathology, and while acute CMV infection is known to influence neutrophil biology, the impact of chronic CMV infection on neutrophil function remains unreported. Using our murine model of CMV infection and latency, we show that chronic CMV causes persistent enhancement of neutrophil oxidative burst well after resolution of acute infection. Moreover, this in vivo priming of marrow neutrophils is associated with enhanced formyl peptide receptor expression, and ultimately constitutive c-Jun N-terminal kinase phosphorylation and enhanced CD14 expression in/on circulating neutrophils. Finally, we show that neutrophil priming is dependent on viral load, suggesting that naturally infected human hosts will show variability in CMV-related neutrophil priming. Altogether, these findings represent a previously unrecognized and potentially important impact of chronic CMV infection on neutrophil responsiveness in immunocompetent hosts.

A novel lncRNA-mediated epigenetic regulatory mechanism in periodontitis

Periodontitis is a highly prevalent chronic inflammatory disease with an exaggerated host immune response, resulting in periodontal tissue destruction and potential tooth loss. The long non-coding RNA, LncR-ANRIL, located on human chromosome 9p21, is recognized as a genetic risk factor for various conditions, including atherosclerosis, periodontitis, diabetes, and cancer. LncR-APDC is an ortholog of ANRIL located on mouse genome chr4. This study aims to comprehend the regulatory role of lncR-APDC in periodontitis progression. Our experimental findings, obtained from lncR-APDC gene knockout (KO) mice with induced experimental periodontitis (EP), revealed exacerbated bone loss and disrupted pro-inflammatory cytokine regulation. Downregulation of osteogenic differentiation occurred in bone marrow stem cells harvested from lncR-APDC-KO mice. Furthermore, single-cell RNA sequencing of periodontitis gingival tissue revealed alterations in the proportion and function of immune cells, including T and B cells, macrophages, and neutrophils, due to lncR-APDC silencing. Our findings also unveiled a previously unidentified epithelial cell subset that is distinctively presenting in the lncR-APDC-KO group. This epithelial subset, characterized by the positive expression of Krt8 and Krt18, engages in interactions with immune cells through a variety of ligand-receptor pairs. The expression of Tff2, now recognized for its role in chronic inflammatory conditions, exhibited a notable increase across various tissue and cell types in lncR-APDC deficient mice. Additionally, our investigation revealed the potential for a direct binding interaction between lncR-APDC and Tff2. Intra-gingival administration of AAV9-lncR-APDC was shown to have therapeutic effects in the EP model. In conclusion, our results suggest that lncR-APDC plays a critical role in the progression of periodontal disease and holds therapeutic potential for periodontitis. Furthermore, the presence of the distinctive epithelial subpopulation and significantly elevated Tff2 levels in the lncR-APDC-silenced EP model offer new perspectives on the epigenetic regulation of periodontitis pathogenesis.

The association between neutrophil-to-lymphocyte ratio and disease activity in rheumatoid arthritis

The inflammatory response is responsible for the promotion of pannus development over the joint, which is the primary factor in joint injury in rheumatoid arthritis (RA). More in-depth investigations have been conducted in recent years leading to a greater understanding of RA. Yet, it's difficult to gauge inflammation levels in RA patients. Some people who have RA do not exhibit normal symptoms, which makes it more challenging to make a diagnosis. Typical RA evaluations are subject to a few restrictions. Earlier research demonstrated that some patients continued to experience the progression of bone and joint degeneration even while in clinical remission. This progression was attributed to ongoing synovial inflammation. As a result, performing a precise evaluation of the level of inflammation is of the utmost importance. The neutrophil-to-lymphocyte ratio (NLR) has consistently been one of the most interesting novel non-specific inflammatory indicators. It is a reflection of the equilibrium between lymphocytes and neutrophils, which are inflammatory regulators and inflammatory activators, respectively. A higher NLR is linked to more severe levels of imbalance and inflammation. The aim of this study was to depict the role of NLR in RA progression and to show if NLR could predict the response to disease-modifying antirheumatic drugs (DMARDs) therapy in RA.

Pyroptosis: the potential eye of the storm in adult-onset Still's disease

Pyroptosis, a form of programmed cell death with a high pro-inflammatory effect, causes cell lysis and leads to the secretion of countless interleukin-1β (IL-1β) and IL-18 cytokines, resulting in a subsequent extreme inflammatory response through the caspase-1-dependent pathway or caspase-1-independent pathway. Adult-onset Still's disease (AOSD) is a systemic inflammatory disease with extensive disease manifestations and severe complications such as macrophage activation syndrome, which is characterized by high-grade inflammation and cytokine storms regulated by IL-1β and IL-18. To date, the pathogenesis of AOSD is unclear, and the available therapy is unsatisfactory. As such, AOSD is still a challenging disease. In addition, the high inflammatory states and the increased expression of multiple pyroptosis markers in AOSD indicate that pyroptosis plays an important role in the pathogenesis of AOSD. Accordingly, this review summarizes the molecular mechanisms of pyroptosis and describes the potential role of pyroptosis in AOSD, the therapeutic practicalities of pyroptosis target drugs in AOSD, and the therapeutic blueprint of other pyroptosis target drugs.

An unexpected role of neutrophils in clearing apoptotic hepatocytes in vivo

Billions of apoptotic cells are removed daily in a human adult by professional phagocytes (e.g. macrophages) and neighboring nonprofessional phagocytes (e.g. stromal cells). Despite being a type of professional phagocyte, neutrophils are thought to be excluded from apoptotic sites to avoid tissue inflammation. Here, we report a fundamental and unexpected role of neutrophils as the predominant phagocyte responsible for the clearance of apoptotic hepatic cells in the steady state. In contrast to the engulfment of dead cells by macrophages, neutrophils burrowed directly into apoptotic hepatocytes, a process we term perforocytosis, and ingested the effete cells from the inside. The depletion of neutrophils caused defective removal of apoptotic bodies, induced tissue injury in the mouse liver, and led to the generation of autoantibodies. Human autoimmune liver disease showed similar defects in the neutrophil-mediated clearance of apoptotic hepatic cells. Hence, neutrophils possess a specialized immunologically silent mechanism for the clearance of apoptotic hepatocytes through perforocytosis, and defects in this key housekeeping function of neutrophils contribute to the genesis of autoimmune liver disease.

Neutrophil-lymphocyte ratio and clinical outcomes in 19,697 patients with atrial fibrillation: Analyses from ENGAGE AF- TIMI 48 trial

BACKGROUND

The neutrophil-to-lymphocyte ratio (NLR) is the ratio between neutrophil and lymphocyte counts measured in peripheral blood. NLR is easily calculable based on a routine blood test available worldwide and may reflect systemic inflammation. However, the relationship between NLR and clinical outcomes in atrial fibrillation (AF) patients is not well-described.

METHODS

We calculated NLR at baseline in ENGAGE AF-TIMI 48, a randomized trial comparing edoxaban versus warfarin in patients with AF followed for 2.8 years (median). The association of baseline NLR with major bleeding events, major adverse cardiac events (MACE), cardiovascular death, stroke/systemic embolism, and all-cause mortality were calculated.

RESULTS

The median baseline NLR in 19,697 patients was 2.53 (interquartile range 1.89-3.41). NLR was associated with major bleeding events (HR 1.60; 95% CI 1.41-1.80), stroke/systemic embolism (HR 1.25; 95% CI, 1.09-1.44), MI (HR 1.73; 95% CI 1.41-2.12), MACE (HR 1.70; 95% CI 1.56-1.84), CV (HR 1.93; 95% CI 1.74-2.13) and all-cause mortality (HR 2.00; 95% CI 1.83-2.18). The relationships between NLR and outcomes remained significant after adjustment for risk factors. Edoxaban consistently reduced major bleeding. MACE, and CV death across NLR groups vs. warfarin.

CONCLUSIONS

NLR represents a widely available, simple, arithmetic calculation that could be immediately and automatically reported during a white blood cell differential measurement to identify patients with AF at increased risk of bleeding, CV events, and mortality.

Human plasma kallikrein: roles in coagulation, fibrinolysis, inflammation pathways, and beyond

Human plasma kallikrein (PKa) is obtained by activating its precursor, prekallikrein (PK), historically named the Fletcher factor. Human PKa and tissue kallikreins are serine proteases from the same family, having high- and low-molecular weight kininogens (HKs and LKs) as substrates, releasing bradykinin (Bk) and Lys-bradykinin (Lys-Bk), respectively. This review presents a brief history of human PKa with details and recent observations of its evolution among the vertebrate coagulation proteins, including the relations with Factor XI. We explored the role of Factor XII in activating the plasma kallikrein-kinin system (KKS), the mechanism of activity and control in the KKS, and the function of HK on contact activation proteins on cell membranes. The role of human PKa in cell biology regarding the contact system and KSS, particularly the endothelial cells, and neutrophils, in inflammatory processes and infectious diseases, was also approached. We examined the natural plasma protein inhibitors, including a detailed survey of human PKa inhibitors' development and their potential market.

Micro- and Macrovascular Effects of Inflammation in Peripheral Artery Disease-Pathophysiology and Translational Therapeutic Approaches

Inflammation has a critical role in the development and progression of atherosclerosis. On the molecular level, inflammatory pathways negatively impact endothelial barrier properties and thus, tissue homeostasis. Conformational changes and destruction of the glycocalyx further promote pro-inflammatory pathways also contributing to pro-coagulability and a prothrombotic state. In addition, changes in the extracellular matrix composition lead to (peri-)vascular remodelling and alterations of the vessel wall, e.g., aneurysm formation. Moreover, progressive fibrosis leads to reduced tissue perfusion due to loss of functional capillaries. The present review aims at discussing the molecular and clinical effects of inflammatory processes on the micro- and macrovasculature with a focus on peripheral artery disease.

Low-density granulocytes display immature cells with enhanced NET formation in people living with HIV

While the protective role of neutrophil extracellular traps (NETs) in limiting human immunodeficiency virus (HIV) spread to susceptible cells has been documented, there is comparatively little insight into whether NET formation is harmful in people living with HIV (PLWH). To gain insight into neutrophil dysregulation and the pathological role of NETs in HIV, we examined expressions of NET-associated markers [cell-free DNA (cfDNA) and citrullinated histone H3 (CitH3)] in the plasmas from a cohort of the Hawaii Aging with HIV-cardiovascular and HIV-seronegative (HIV-) individuals. In a subset of participants, circulating low-density granulocyte (LDG) levels and their maturation and activation status were analyzed via flow cytometry. We demonstrated higher plasma levels of CitH3 in PLWH compared to HIV- individuals. LDGs from PLWH had heightened CD66b, but reduced CD16 expression. The percentages and counts of CD10+ LDGs were significantly decreased in PLWH. In addition, the CD16Lo LDG subsets were enriched in PLWH, compared to HIV- group, indicating that immature LDGs are increased in PLWH. Moreover, LDGs from PLWH exhibited significantly higher NET forming capacity. In summary, our study presents evidence that LDGs from PLWH on ART display an immature and altered phenotype with increased NET formation. Among PLWH, plasma NET levels as well as LDG parameters correlated with blood markers for inflammation and coagulation, suggesting that neutrophil activation and NETs may exert proinflammatory and coagulation effects. Our data provide insights into the pathologic role of LDGs at least in part mediated through NET formation in PLWH.

The double-edged role of neutrophil heterogeneity in inflammatory diseases and cancers

Neutrophils are important immune cells act as the body's first line of defense against infection and respond to diverse inflammatory cues. Many studies have demonstrated that neutrophils display plasticity in inflammatory diseases and cancers. Clarifying the role of neutrophil heterogeneity in inflammatory diseases and cancers will contribute to the development of novel treatment strategies. In this review, we have presented a review on the development of the understanding on neutrophil heterogeneity from the traditional perspective and a high-resolution viewpoint. A growing body of evidence has confirmed the double-edged role of neutrophils in inflammatory diseases and tumors. This may be due to a lack of precise understanding of the role of specific neutrophil subsets in the disease. Thus, elucidating specific neutrophil subsets involved in diseases would benefit the development of precision medicine. Thusly, we have summarized the relevance and actions of neutrophil heterogeneity in inflammatory diseases and cancers comprehensively. Meanwhile, we also discussed the potential intervention strategy for neutrophils. This review is intended to deepen our understanding of neutrophil heterogeneity in inflammatory diseases and cancers, while hold promise for precise treatment of neutrophil-related diseases.

Impact of P-selectin-PSGL-1 Axis on Platelet-Endothelium-Leukocyte Interactions in Fatal COVID-19

In critically ill patients infected with SARS-CoV-2, early leukocyte recruitment to the respiratory system was found to be orchestrated by leukocyte trafficking molecules accompanied by massive secretion of proinflammatory cytokines and hypercoagulability. Our study aimed to explore the interplay between leukocyte activation and pulmonary endothelium in different disease stages of fatal COVID-19. Our study comprised 10 COVID-19 postmortem lung specimens and 20 control lung samples (5 acute respiratory distress syndrome, 2 viral pneumonia, 3 bacterial pneumonia, and 10 normal), which were stained for antigens representing the different steps of leukocyte migration: E-selectin, P-selectin, PSGL-1, ICAM1, VCAM1, and CD11b. Image analysis software QuPath was used for quantification of positive leukocytes (PSGL-1 and CD11b) and endothelium (E-selectin, P-selectin, ICAM1, VCAM1). Expression of IL-6 and IL-1β was quantified by RT-qPCR. Expression of P-selectin and PSGL-1 was strongly increased in the COVID-19 cohort compared with all control groups (COVID-19:Controls, 17:23, P < .0001; COVID-19:Controls, 2:75, P < .0001, respectively). Importantly, P-selectin was found in endothelial cells and associated with aggregates of activated platelets adherent to the endothelial surface in COVID-19 cases. In addition, PSGL-1 staining disclosed positive perivascular leukocyte cuffs, reflecting capillaritis. Moreover, CD11b showed a strongly increased positivity in COVID-19 compared with all controls (COVID-19:Controls, 2:89; P = .0002), indicating a proinflammatory immune microenvironment. Of note, CD11b exhibited distinct staining patterns at different stages of COVID-19 disease. Only in cases with very short disease course, high levels of IL-1β and IL-6 mRNA were observed in lung tissue. The striking upregulation of PSGL-1 and P-selectin reflects the activation of this receptor-ligand pair in COVID-19, increasing the efficiency of initial leukocyte recruitment, thus promoting tissue damage and immunothrombosis. Our results show that endothelial activation and unbalanced leukocyte migration play a central role in COVID-19 involving the P-selectin-PSGL-1 axis.

Beyond Angiogenesis: The Multitasking Approach of the First PEGylated Vascular Endothelial Growth Factor (CdtVEGF) from Brazilian Rattlesnake Venom

A pioneering study regarding the isolation, biochemical evaluation, functional assays and first PEGylation report of a novel vascular endothelial growth factor from Crotalus durissus terrificus venom (CdtVEGF and PEG-CdtVEGF). CdtVEGF was isolated from crude venom using two different chromatographic steps, representing 2% of soluble venom proteins. Its primary sequence was determined using mass spectrometry analysis, and the molecule demonstrated no affinity to heparin. The Brazilian crotalid antivenom recognized CdtVEGF. Both native and PEGylated CdtVEGF were able to induce new vessel formation and migration, and to increase the metabolic activity of human umbilical endothelial vascular cells (HUVEC), resulting in better wound closure (~50% within 12 h) using the native form. CdtVEGF induced leukocyte recruitment to the peritoneal cavity in mice, with a predominance of neutrophil influx followed by lymphocytes, demonstrating the ability to activate the immune system. The molecule also induced a dose-dependent increase in vascular permeability, and PEG-CdtVEGF showed less in vivo inflammatory activity than CdtVEGF. By unraveling the intricate properties of minor components of snake venom like svVEGF, this study illuminates the indispensable significance of exploring these molecular tools to unveil physiological and pathological processes, elucidates the mechanisms of snakebite envenomings, and could possibly be used to design a therapeutic drug.

Hematological Indices Are Useful in Predicting Complications of Liver Cirrhosis

BACKGROUND

Liver cirrhosis is the final stage of chronic liver disease. We aimed to evaluate non-invasive scores as predictors of complications and outcome in cirrhotic patients.

METHODS

A total of 150 cirrhotic patients were included. Models for end-stage liver disease (MELD), albumin-bilirubin (ALBI) score, neutrophil-lymphocyte ratio (NLR), monocyte-lymphocyte ratio (MoLR), and neutrophil-lymphocyte-albumin ratio (NLA) scores were tested in relation to the development of complications and mortality using receiver operating characteristic (ROC) curves.

RESULTS

The ROC curve analysis showed (area under the curve) AUC values of NLR, NLA, ALBI, and MELD of 0.711, 0.730, 0.627, and 0.684, respectively, for short-term mortality. MELD, ALBI, and NLA scores showed a statistically significant correlation with hepatic encephalopathy (p = 0.000 vs. 0.014 vs. 0.040, respectively), and the MELD cut-off value of 16 had a sensitivity of 70% and a specificity of 52% (AUC: 0.671, 95% CI (0.577-0.765)). For the assessment of the presence of ascites, the AUC values for NLA and MoLR were 0.583 and 0.658, respectively, with cut-offs of 11.38 and 0.44.

CONCLUSIONS

MELD, ALBI, and NLA are reliable predictors of hepatic encephalopathy. NLA and MoLR showed a significant correlation with the presence of ascites, and MELD, ALBI, NLR, and NLA have prognostic value to predict 30-day mortality in cirrhotic patients.

Crosstalk of Inflammation and Coagulation in Bothrops Snakebite Envenoming: Endogenous Signaling Pathways and Pathophysiology

Snakebite envenoming represents a major health problem in tropical and subtropical countries. Considering the elevated number of accidents and high morbidity and mortality rates, the World Health Organization reclassified this disease to category A of neglected diseases. In Latin America, Bothrops genus snakes are mainly responsible for snakebites in humans, whose pathophysiology is characterized by local and systemic inflammatory and degradative processes, triggering prothrombotic and hemorrhagic events, which lead to various complications, organ damage, tissue loss, amputations, and death. The activation of the multicellular blood system, hemostatic alterations, and activation of the inflammatory response are all well-documented in Bothrops envenomings. However, the interface between inflammation and coagulation is still a neglected issue in the toxinology field. Thromboinflammatory pathways can play a significant role in some of the major complications of snakebite envenoming, such as stroke, venous thromboembolism, and acute kidney injury. In addition to exacerbating inflammation and cell interactions that trigger vaso-occlusion, ischemia-reperfusion processes, and, eventually, organic damage and necrosis. In this review, we discuss the role of inflammatory pathways in modulating coagulation and inducing platelet and leukocyte activation, as well as the inflammatory production mediators and induction of innate immune responses, among other mechanisms that are altered by Bothrops venoms.

MicroRNAs and Periodontal Disease: Helpful Therapeutic Targets?

Periodontal disease is the most common oral disease. This disease can be considered as an inflammatory disease. The immune response to bacteria accumulated in the gum line plays a key role in the pathogenesis of periodontal disease. In addition to immune cells, periodontal ligament cells and gingival epithelial cells are also involved in the pathogenesis of this disease. miRNAs which are small RNA molecules with around 22 nucleotides have a considerable relationship with the immune system affecting a wide range of immunological events. These small molecules are also in relation with periodontium tissues especially periodontal ligament cells. Extensive studies have been performed in recent years on the role of miRNAs in the pathogenesis of periodontal disease. In this review paper, we have reviewed the results of these studies and discussed the role of miRNAs in the immunopathogenesis of periodontal disease comprehensively. miRNAs play an important role in the pathogenesis of periodontal disease and maybe helpful therapeutic targets for the treatment of periodontal disease.

HLA-DR Expression on Monocytes and Sepsis Index Are Useful in Predicting Sepsis

The reduction of mortality in patients with sepsis depends on the early identification and treatment of at-risk patients. The aim was to evaluate the HLA-DR expression on the surface of monocytes (_MHLA-DR ratio), the sepsis index (CD64 expression on neutrophils/_MHLA-DR ratio), and C-reactive protein (CRP) with the development of sepsis. We prospectively enrolled 77 critically ill patients, 59 with stroke and 18 with traumatic brain injuries. The biomarkers were tested at the baseline and 3, 6, 9, 12, and 15 days later. Most patients (71%) developed sepsis (4.2 ± 1.3 days after admission). On day 3, those subsequently developing sepsis had lower levels of _MHLA-DR+ (81.7 ± 16.2% vs. 88.5 ± 12.1%, p < 0.05) and higher sepsis indexes (0.19 ± 0.19 vs. 0.08 ± 0.08, p < 0.01) than those not developing sepsis. The _MHLA-DR ratio slowly recovered before day 6, while the sepsis index remained raised in septic patients up to day 9 (p < 0.05). To predict the development of sepsis, optimal cut-offs were CRP levels > 106.90 mg/mL (74.19% sensitivity, 69.49 specificity) and _MHLA-DR expression rate < 72.80% (45.31% sensitivity, 89.47% specificity). The periodic monitoring of the _MHLA-DR expression together with CRP and sepsis index may help to identify patients in the ICU at increased risk of developing sepsis.

Integrative profiling of gene expression and chromatin accessibility elucidates specific transcriptional networks in porcine neutrophils

Neutrophils are vital components of the immune system for limiting the invasion and proliferation of pathogens in the body. Surprisingly, the functional annotation of porcine neutrophils is still limited. The transcriptomic and epigenetic assessment of porcine neutrophils from healthy pigs was performed by bulk RNA sequencing and transposase accessible chromatin sequencing (ATAC-seq). First, we sequenced and compared the transcriptome of porcine neutrophils with eight other immune cell transcriptomes to identify a neutrophil-enriched gene list within a detected neutrophil co-expression module. Second, we used ATAC-seq analysis to report for the first time the genome-wide chromatin accessible regions of porcine neutrophils. A combined analysis using both transcriptomic and chromatin accessibility data further defined the neutrophil co-expression network controlled by transcription factors likely important for neutrophil lineage commitment and function. We identified chromatin accessible regions around promoters of neutrophil-specific genes that were predicted to be bound by neutrophil-specific transcription factors. Additionally, published DNA methylation data from porcine immune cells including neutrophils were used to link low DNA methylation patterns to accessible chromatin regions and genes with highly enriched expression in porcine neutrophils. In summary, our data provides the first integrative analysis of the accessible chromatin regions and transcriptional status of porcine neutrophils, contributing to the Functional Annotation of Animal Genomes (FAANG) project, and demonstrates the utility of chromatin accessible regions to identify and enrich our understanding of transcriptional networks in a cell type such as neutrophils.

The Role of Neutrophil-to-Lymphocyte Ratio in Advanced EGFR-Mutant NSCLC Patients Treated with First-Line Osimertinib

Purpose

Although serum neutrophil-to-lymphocyte ratio (NLR) is correlated with the outcome of various cancer types, its role in treatment-naïve, advanced, epidermal growth factor receptor (EGFR)-mutant non-small cell lung cancer (NSCLC) patients treated with osimertinib remains uncertain. We have the intention to use this biomarker to evaluate the outcomes in NSCLC.

Patients and Methods

Advanced EGFR-mutant NSCLC patients receiving osimertinib as the first-line treatment were included. We evaluated the prognostic role of baseline NLR and explored its association with patients' characteristics. A high NLR was defined as pretreatment serum NLR ≥ 5.

Results

A total of 112 eligible patients were included. The objective response rate was 83.7%. The median progression-free survival (PFS) and overall survival (OS) were 20.5 months (95% CI 14.5-26.5) and 47.3 months (95% CI 36.7-58.2), respectively. A high NLR predicted an inferior PFS (HR 1.90 [95% CI 1.02-3.51], P = 0.042) and OS (HR 3.85 [95% CI 1.39-10.66], P = 0.009). Patients with stage IVB disease were more likely to have a high baseline NLR than those with stage IIIB-IVA (33.9% vs 15.1%, P = 0.029). Other patients' characteristics did not correlate with the baseline NLR significantly. Patients with a high NLR had significantly more metastatic organs than those with a low NLR (2.5 ± 1.3 vs 1.8 ± 0.9, P = 0.012), particularly brain, liver, and bone metastasis. There was no significant association between NLR and intrathoracic metastasis.

Conclusion

Baseline serum NLR could act as an important prognostic marker for EGFR-mutant NSCLC patients receiving first-line osimertinib. A high NLR was associated with higher metastatic burden, more extrathoracic metastases, and therefore, a worse outcome.

Temperature Trajectory Subphenotypes in Oncology Patients with Neutropenia and Suspected Infection

Rationale: Despite etiologic and severity heterogeneity in neutropenic sepsis, management is often uniform. Understanding host response clinical subphenotypes might inform treatment strategies for neutropenic sepsis. Objectives: In this retrospective two-hospital study, we analyzed whether temperature trajectory modeling could identify distinct, clinically relevant subphenotypes among oncology patients with neutropenia and suspected infection. Methods: Among adult oncologic admissions with neutropenia and blood cultures within 24 hours, a previously validated model classified patients' initial 72-hour temperature trajectories into one of four subphenotypes. We analyzed subphenotypes' independent relationships with hospital mortality and bloodstream infection using multivariable models. Measurements and Main Results: Patients (primary cohort n = 1,145, validation cohort n = 6,564) fit into one of four temperature subphenotypes. "Hyperthermic slow resolvers" (pooled n = 1,140 [14.8%], mortality n = 104 [9.1%]) and "hypothermic" encounters (n = 1,612 [20.9%], mortality n = 138 [8.6%]) had higher mortality than "hyperthermic fast resolvers" (n = 1,314 [17.0%], mortality n = 47 [3.6%]) and "normothermic" (n = 3,643 [47.3%], mortality n = 196 [5.4%]) encounters (P < 0.001). Bloodstream infections were more common among hyperthermic slow resolvers (n = 248 [21.8%]) and hyperthermic fast resolvers (n = 240 [18.3%]) than among hypothermic (n = 188 [11.7%]) or normothermic (n = 418 [11.5%]) encounters (P < 0.001). Adjusted for confounders, hyperthermic slow resolvers had increased adjusted odds for mortality (primary cohort odds ratio, 1.91 [P = 0.03]; validation cohort odds ratio, 2.19 [P < 0.001]) and bloodstream infection (primary odds ratio, 1.54 [P = 0.04]; validation cohort odds ratio, 2.15 [P < 0.001]). Conclusions: Temperature trajectory subphenotypes were independently associated with important outcomes among hospitalized patients with neutropenia in two independent cohorts.

ROS fine-tunes the function and fate of immune cells

The redox state is essential to the process of cell life, which determines cell fate. As an important signaling molecule of the redox state, reactive oxygen species (ROS) are crucial for the homeostasis of immune cells and participate in the pathological processes of different diseases. We discuss the underlying mechanisms and possible signaling pathways of ROS to fine-tune the proliferation, differentiation, polarization and function of immune cells, including T cells, B cells, neutrophils, macrophages, myeloid-derived inhibitory cells (MDSCs) and dendritic cells (DCs). We further emphasize how excessive ROS lead to programmed immune cell death such as apoptosis, ferroptosis, pyroptosis, NETosis and necroptosis, providing valuable insights for future therapeutic strategies in human diseases.

Comparison of the effects of electronic cigarette vapours and tobacco smoke extracts on human neutrophils in vitro

Background

Electronic cigarettes (ECs) are electronic aerosol delivery systems composed of nicotine and various chemicals, which are widely used to facilitate smoking cessation. Although ECs are considered safer than cigarettes, they do, however, contain chemical toxicants, some of which may interact with cells of the host's innate immune system of which neutrophils constitute a key component.

Methods

The current study was designed to compare the effects of aqueous EC aerosol extracts (ECEs; with or without nicotine) with those of cigarette smoke extract (CSE) on neutrophil and platelet reactivity in vitro. Neutrophil reactivity is characterised by the generation of reactive oxygen species (ROS), degranulation (elastase release) and the release of extracellular DNA (neutrophil extracellular trap (NET) formation: NETosis), which were measured using chemiluminescence, spectrophotometric and microscopic procedures, respectively. Platelet reactivity was measured according to the magnitude of upregulated expression of the adhesion molecule CD62P on activated cells using a flow cytometric procedure.

Results

Exposure of neutrophils to either ECEs or CSE caused a significant inhibition of ROS generation and elastase release by N-formyl-l-methionyl-l-leucyl-l-phenylalanine (1 µM)-activated neutrophils. Pre-treatment of neutrophils with CSE also resulted in a marked attenuation of phorbol 12-myristate 13-acetate (6.25 nM)-mediated release of extracellular DNA, which was unaffected by the ECEs. Similarly, CSE, but not the ECEs, inhibited the expression of CD62P by platelets activated with ADP (100 µM).

Conclusions

These observations suggest that ECE aerosols may inhibit some of the immuno-protective activities of neutrophils such as ROS production and elastase release by activated cells, the effect of which was not enhanced by inclusion of nicotine. The inhibitory effects of CSE were significantly more pronounced than those of ECEs, especially so for suppression of NET formation and platelet activation. If operative in vivo, these harmful immunosuppressive effects of ECEs may compromise intrinsic pulmonary antimicrobial defence mechanisms, albeit less so than cigarette smoke.

The Regulation of Neutrophil Migration in Patients with Sepsis: The Complexity of the Molecular Mechanisms and Their Modulation in Sepsis and the Heterogeneity of Sepsis Patients

Sepsis is defined as life-threatening organ dysfunction caused by a dysregulated host response to infection. Common causes include gram-negative and gram-positive bacteria as well as fungi. Neutrophils are among the first cells to arrive at an infection site where they function as important effector cells of the innate immune system and as regulators of the host immune response. The regulation of neutrophil migration is therefore important both for the infection-directed host response and for the development of organ dysfunctions in sepsis. Downregulation of CXCR4/CXCL12 stimulates neutrophil migration from the bone marrow. This is followed by transmigration/extravasation across the endothelial cell barrier at the infection site; this process is directed by adhesion molecules and various chemotactic gradients created by chemotactic cytokines, lipid mediators, bacterial peptides, and peptides from damaged cells. These mechanisms of neutrophil migration are modulated by sepsis, leading to reduced neutrophil migration and even reversed migration that contributes to distant organ failure. The sepsis-induced modulation seems to differ between neutrophil subsets. Furthermore, sepsis patients should be regarded as heterogeneous because neutrophil migration will possibly be further modulated by the infecting microorganisms, antimicrobial treatment, patient age/frailty/sex, other diseases (e.g., hematological malignancies and stem cell transplantation), and the metabolic status. The present review describes molecular mechanisms involved in the regulation of neutrophil migration; how these mechanisms are altered during sepsis; and how bacteria/fungi, antimicrobial treatment, and aging/frailty/comorbidity influence the regulation of neutrophil migration.