The Role of Neutrophils and Their Extracellular Traps in the Synergy of Pre-eclampsia and HIV Infection

Multifaceted roles of neutrophils in cardiac disease

Neutrophils, the most abundant leukocytes in human blood, have long been recognized as critical first responders in the innate immune system's defense against pathogens. Some of the more notable innate antimicrobial properties of neutrophils include generation of superoxide free radicals like myeloperoxidase, production of proteases that reshape the extracellular matrix allowing for easier access to infected tissues, and release of neutrophil extracellular traps, extruded pieces of DNA that ensnare bacterial and fungi. These mechanisms developed to provide neutrophils with a vast array of specialized functions to provide the host defense against infection in an acute setting. However, emerging evidence over the past few decades has revealed a far more complex and nuanced role for these neutrophil-driven processes in various chronic conditions, particularly in cardiovascular diseases. The pathophysiology of cardiac diseases involves a complex interplay of hemodynamic, neurohumoral, and inflammatory factors. Neutrophils, as key mediators of inflammation, contribute significantly to this intricate network. Their involvement extends far beyond their classical role in pathogen clearance, encompassing diverse functions that can both exacerbate tissue damage and contribute to repair processes. Here, we consider the contributions of neutrophils to myocardial infarction, heart failure, cardiac arrhythmias, and nonischemic cardiomyopathies. Understanding these complex interactions is crucial for developing novel therapeutic strategies aimed at modulating neutrophil functions in these highly morbid cardiac diseases.

Neutrophil extracellular traps - an a-list-actor in a variety of diseases

Neutrophil extracellular traps (NETs) represent a response mechanism in which activated neutrophils release DNA-based webs, adorned with histones and neutrophil proteases, to capture and eliminate invasive microorganisms. However, when these neutrophils become excessively activated, much more proteases associated with NETs are liberated into surrounding tissues or bloodstreams, thereby altering the cellular milieu and causing tissue damage. Recent research has revealed that NETs may play significant roles in the emergence and progression of various diseases, spanning from infections, inflammation to autoimmune disorders and cancers. In this review, we delve deeply into the intricate and complex mechanisms that underlie the formation of NETs and their profound interplay with various clinical pathologies. We aim to describe the application perspectives of NETs related proteins in specific disease diagnosis and treatment.

Clinical aPDT's effect on Candida albicans: Antifungal susceptibility, virulence gene expression, and correlation with leukocyte and neutrophil counts

BACKGROUND

Our previous clinical trial demonstrated that antimicrobial photodynamic therapy (aPDT) with methylene blue (MB) and potassium iodide (KI) effectively killed Candida albicans (C. albicans) in adult AIDS patients with oral candidiasis, regardless of biofilm formation or 25S rDNA genotype. This study evaluated changes in antifungal susceptibility and virulence gene expression in C. albicans before and after aPDT, and explored factors related to clinical aPDT efficacy.

METHODS

Twenty-one adult AIDS patients with C. albicans oral candidiasis were divided into Group a (400 μM MB, N = 11) and Group b (600 μM MB, N = 10). Both groups received two aPDT treatments, where MB was applied for 5 min, followed by 300 mM KI, and illuminated for 30 min (37.29 J/cm²). C. albicans isolates were collected before and after treatment to assess antifungal susceptibility (fluconazole, itraconazole, flucytosine, amphotericin B) and gene expression (CAT1, HWP1). Peripheral blood tests were analyzed for correlations with aPDT efficacy.

RESULTS

aPDT reduced minimum inhibitory concentration (MIC) values for amphotericin B, fluconazole, and flucytosine, with significant reductions primarily after the first treatment. MIC reductions differed between groups, with Group a showing greater decreases in flucytosine and fluconazole MICs, and Group b in amphotericin B MICs. No significant changes in CAT1 or HWP1 expression were observed. Clinical efficacy of aPDT negatively correlated with leukocyte and neutrophil levels.

CONCLUSIONS

aPDT effectively reduces MICs of antifungal drugs against C. albicans isolated from treated patients, particularly after the first treatment. The concentration of MB required to reduce MICs varies among different antifungal drugs. aPDT does not alter CAT1 or HWP1 expression, and its clinical efficacy in eradicating C. albicans is negatively associated with leukocyte and neutrophil levels.

Placental neutrophil reverse trans-migration and maternal serum neutrophil extracellular trap expression in HIV infection co-morbid pre-eclampsia in women of African ancestry

Neutrophil extracellular traps (NETs) and placental neutrophil reverse transmigration (r-TM) are implicated in the pathogenesis of pre-eclampsia (PE). However, the role of the comorbidity of PE and human immunodeficiency virus (HIV) infection in placental neutrophil r-TM and serum NETs remains unknown. Human placental tissue (n = 160) and serum (n = 80) samples were obtained post-ethical approval and divided by pregnancy type and HIV status and across the study population. Immunohistochemistry and morphometry were performed to localize and quantify junctional adhesion molecule-C (JAM-C) expression as an inverse marker of neutrophil r-TM within placental villi. An enzyme-linked immunosorbent assay (ELISA) was performed to quantify the concentration of citrullinated histone H3 (cit-H3) as a marker of NETs. GraphPad Prism (version 8.0.2) was used to compare the results, and a p value of p < 0.05 was considered statistically significant. The localization of JAM-C was observed on the syncytiotrophoblasts (STBs) and endothelial cells of placental villi. The immunoexpression of JAM-C was elevated in PE vs. normotensive (N) placentae. In the exchange villi, JAM-C immunoexpression was higher in the N+ve vs. N-ve group. However, in PE comorbid HIV infection, JAM-C expression was lower in the PE+ve vs. PE-ve group. Citrullinated histone-H3 concentration was lower in the N+ve vs. N-ve group but elevated in early-onset PE (EOPE)+ve vs. late-onset PE (LOPE)+ve group. These results indicate that PE and HIV-infected placentae individually express elevated JAM-C, manifesting in less neutrophil r-TM. However, in exchange villi of PE comorbid with HIV infection reduced JAM-C enhances neutrophil r-TM, thus supporting the synergistic effect of PE comorbid with HIV.

Neutrophil extracellular traps in homeostasis and disease

Neutrophil extracellular traps (NETs), crucial in immune defense mechanisms, are renowned for their propensity to expel decondensed chromatin embedded with inflammatory proteins. Our comprehension of NETs in pathogen clearance, immune regulation and disease pathogenesis, has grown significantly in recent years. NETs are not only pivotal in the context of infections but also exhibit significant involvement in sterile inflammation. Evidence suggests that excessive accumulation of NETs can result in vessel occlusion, tissue damage, and prolonged inflammatory responses, thereby contributing to the progression and exacerbation of various pathological states. Nevertheless, NETs exhibit dual functionalities in certain pathological contexts. While NETs may act as autoantigens, aggregated NET complexes can function as inflammatory mediators by degrading proinflammatory cytokines and chemokines. The delineation of molecules and signaling pathways governing NET formation aids in refining our appreciation of NETs' role in immune homeostasis, inflammation, autoimmune diseases, metabolic dysregulation, and cancer. In this comprehensive review, we delve into the multifaceted roles of NETs in both homeostasis and disease, whilst discussing their potential as therapeutic targets. Our aim is to enhance the understanding of the intricate functions of NETs across the spectrum from physiology to pathology.

Investigations of leukocyte and inflammatory markers in pregnancies complicated by preeclampsia

OBJECTIVES

Preeclampsia is a frequent and potentially fatal pregnancy complication. It can be challenging to make a timely diagnosis. Identifying clinically useful biochemical markers would be a remedying tool to support the diagnosis of preeclampsia. The aim was to investigate differential cell counts and acute phase reactants as diagnostic markers of preeclamptic third-trimester pregnancies and in relation to pregnancy term, gravidity and the severity of hypertension.

METHODS

Based on a cohort of 421 pregnant women, we included 174 participants (case n = 84, control n = 90) during the third trimester. Peripheral blood was sampled to measure differential white blood cell counts and acute phase reactants on the day of inclusion.

RESULTS

The neutrophil-to-lymphocyte ratio and plasma haptoglobin levels were significantly increased in healthy pregnancies compared with preeclamptic pregnancies. Plasma ferritin levels and albumin levels were respectively increased and decreased in cases of preeclampsia compared with controls. Albumin was specific among multigravida. Plasma transferrin and high-sensitivity C-reactive protein (hs-CRP) levels were significantly decreased and increased, respectively, in cases with preterm preeclampsia compared with term preeclampsia.

CONCLUSION

Plasma ferritin and albumin levels reflected higher inflammation in cases with preeclampsia compared with healthy pregnancies; the same did plasma transferrin and hs-CRP levels in preterm versus term preeclampsia. When considering the normal ranges plasma albumin and hs-CRP levels identified preeclamptic from healthy third-trimester pregnancies and preterm from term preeclampsia cases, respectively, with near-acceptable diagnostic performances. Further validation of the diagnostic value will require larger sample-sized studies with paired plasma and serum samples.

Neutrophil count is a useful marker to predict the severity of preeclampsia

BACKGROUND

At present, pre-eclampsia is a growing concern and still a diagnostic challenge for obstetricians.

AIMS

This study aimed to evaluate whether the relationship of second trimester of pregnancy neutrophil count differed among pregnancies with mild preeclampsia, severe preeclampsia, and healthy status and explore whether or not neutrophil count in the second trimester of pregnancy would be useful as new predictors of subsequent preeclampsia.

PATIENTS AND METHODS

This study involved 933 pregnancies from 1 January 2018 to 30 January 2021, comprising 396 healthy pregnancies, 222 pregnancies with mild preeclampsia, and 315 pregnancies with severe preeclampsia. The relationship between preeclampsia and neutrophil count was analyzed by multiple logistic regression. In addition, maternal placental tissues of three groups were immunohistochemically stained for myeloperoxidase (MPO).

RESULTS

Neutrophil count was significantly higher in pregnancies with preeclampsia (including pregnancies with mild and severe preeclampsia) than that in healthy pregnancies. The neutrophil count level was prominently higher in patients with severe preeclampsia compared with those with mild preeclampsia (p < .001). The neutrophil count level was significantly positively associated with preeclampsia after adjusting for gestational week at time of blood sampling, BMI, and age (β:1.23; 95%CI:1.09-1.36; p < .0001). In addition, MPO expressions of placental tissues in preeclamptic groups were significantly increased than these in healthy pregnant controls (p < .05).

CONCLUSIONS

Increased neutrophil count in the second trimester of pregnancy was significantly positively associated with preeclampsia. Hence, neutrophil count plays a role in predicting the severity of preeclampsia. At the same time, it may be an independent predictor of subsequent preeclampsia.Abbreviations: BMI: body mass index; MPO: myeloperoxidase.

HIV Associated Preeclampsia: A Multifactorial Appraisal

Introduction: This review explores angiogenesis, vascular dysfunction, the complement system, RAAS, apoptosis and NETosis as potential pathways that are dysregulated during preeclampsia, HIV infection and ART usage. Results: HIV-1 accessory and matrix proteins are protagonists for the elevation of oxidative stress, apoptosis, angiogenesis, and elevation of adhesion markers. Despite the immunodeficiency during HIV-1 infection, HIV-1 exploits our cellular defence arsenal by escaping cell-mediated lysis, yet HIV-1 infectivity is enhanced via C5a release of TNF-α and IL-6. This review demonstrates that PE is an oxidatively stressed microenvironment associated with increased apoptosis and NETosis, but with a decline in angiogenesis. Immune reconstitution in the duality of HIV-1 and PE by protease inhibitors, HAART and nucleoside reverse transcriptase, affect similar cellular pathways that eventuate in loss of endothelial cell integrity and, hence, its dysfunction. Conclusions: HIV-1 infection, preeclampsia and ARTs differentially affect endothelial cell function. In the synergy of both conditions, endothelial dysfunction predominates. This knowledge will help us to understand the effect of HIV infection and ART on immune reconstitution in preeclampsia.

The Role of B Cells in PE Pathophysiology: A Potential Target for Perinatal Cell-Based Therapy?

The pathophysiology of preeclampsia (PE) is poorly understood; however, there is a large body of evidence that suggests a role of immune cells in the development of PE. Amongst these, B cells are a dominant element in the pathogenesis of PE, and they have been shown to play an important role in various immune-mediated diseases, both as pro-inflammatory and regulatory cells. Perinatal cells are defined as cells from birth-associated tissues isolated from term placentas and fetal annexes and more specifically from the amniotic membrane, chorionic membrane, chorionic villi, umbilical cord (including Wharton's jelly), the basal plate, and the amniotic fluid. They have drawn particular attention in recent years due to their ability to modulate several aspects of immunity, making them promising candidates for the prevention and treatment of various immune-mediated diseases. In this review we describe main findings regarding the multifaceted in vitro and in vivo immunomodulatory properties of perinatal cells, with a focus on B lymphocytes. Indeed, we discuss evidence on the ability of perinatal cells to inhibit B cell proliferation, impair B cell differentiation, and promote regulatory B cell formation. Therefore, the findings discussed herein unveil the possibility to modulate B cell activation and function by exploiting perinatal immunomodulatory properties, thus possibly representing a novel therapeutic strategy in PE.