Search results for "monocyte"
showing 10 items of 381 documents
Digestive vacuole of Plasmodium falciparum released during erythrocyte rupture dually activates complement and coagulation.
2012
Abstract Severe Plasmodium falciparum malaria evolves through the interplay among capillary sequestration of parasitized erythrocytes, deregulated inflammatory responses, and hemostasis dysfunction. After rupture, each parasitized erythrocyte releases not only infective merozoites, but also the digestive vacuole (DV), a membrane-bounded organelle containing the malaria pigment hemozoin. In the present study, we report that the intact organelle, but not isolated hemozoin, dually activates the alternative complement and the intrinsic clotting pathway. Procoagulant activity is destroyed by phospholipase C treatment, indicating a critical role of phospholipid head groups exposed at the DV surfa…
Circulating histones contribute to monocyte and MDW alterations as common mediators in classical and COVID-19 sepsis
2022
Abstract Objective Histone proteins are physiologically involved in DNA packaging and gene regulation but are extracellularly released by neutrophil/monocyte extracellular traps and mediate thrombo-inflammatory pathways, associated to the severity of many human pathologies, including bacterial/fungal sepsis and COVID-19. Prominent and promising laboratory features in classic and viral sepsis emphasize monocyte distribution width (MDW), due to its ability to distinguish and stratify patients at higher risk of critical conditions or death. No data are available on the roles of histones as MDW modifiers. Design Comparison of MDW index was undertaken by routine hematology analyzer on whole bloo…
Subviral Dense Bodies of Human Cytomegalovirus Stimulate Maturation and Activation of Monocyte-Derived Immature Dendritic Cells
2013
ABSTRACT Dendritic cells play a central role in the immune control of human cytomegalovirus (HCMV) infection. This work aimed at investigating the impact of noninfectious, subviral dense bodies of HCMV on the maturation and activation of dendritic cells (DC). Treatment of immature DC with dense bodies led to the maturation of these cells and significantly increased their capacity for cytokine release and antigen presentation. Dense body-activated DC may thereby contribute to the development of antiviral immunity.
Identification of biological markers of liver X receptor (LXR) activation at the cell surface of human monocytes.
2012
Background Liver X receptor (LXR) α and LXR β (NR1H3 and NR1H2) are oxysterol-activated nuclear receptors involved in the control of major metabolic pathways such as cholesterol homeostasis, lipogenesis, inflammation and innate immunity. Synthetic LXR agonists are currently under development and could find applications in various fields such as cardiovascular diseases, cancer, diabetes and neurodegenerative diseases. The clinical development of LXR agonists requires the identification of biological markers for pharmacodynamic studies. In this context, monocytes represent an attractive target to monitor LXR activation. They are easily accessible cells present in peripheral blood; they expres…
Isolation and characterization of a pigmentless-conidium mutant of Aspergillus fumigatus with altered conidial surface and reduced virulence.
1997
Aspergillus fumigatus is an important pathogen of immunocompromised hosts, causing pneumonia and invasive disseminated disease with high mortality. The factors contributing to the predominance of A. fumigatus as an opportunistic pathogen are largely unknown. Since the survival of conidia in the host is a prerequisite for establishing disease, we have been attempting to identify factors which are associated with conidia and, simultaneously, important for infection. Therefore, an A. fumigatus mutant strain (white [W]) lacking conidial pigmentation was isolated. Scanning electron microscopy revealed that conidia of the W mutant also differed in their surface morphology from those of the wild t…
Liver X Receptor Regulates Arachidonic Acid Distribution and Eicosanoid Release in Human Macrophages
2013
Objective— Liver X receptors (LXRs) are oxysterol-activated nuclear receptors that are highly expressed in macrophages and regulate lipid homeostasis and inflammation. Among putative LXR target genes, lysophosphatidylcholine acyltransferase 3 (LPCAT3) involved in the Lands cycle controls the fatty acid composition at the sn-2 position of glycerophospholipids and, therefore, the availability of fatty acids, such as arachidonic acid (AA), used for eicosanoid synthesis. The aim of our study was to determine whether LXRs could regulate the Lands cycle in human macrophages, to assess the consequences in terms of lipid composition and inflammatory response, and to work out the relative contribut…
Host–pathogen interactions in Vibrio vulnificus: responses of monocytes and vascular endothelial cells to live bacteria
2015
ABSTRACT Aim: To demonstrate that Vibrio vulnificus, a sepsis-related aquatic pathogen, can provoke a strong pro-inflammatory reaction in blood-associated target cells. Materials & methods: We selected two strains of the two main phylogenetic lineages, two human cell lines, monocytes and vascular endothelial cells and designed an in vitro infection model simulating early septicemia. Results: Both strains caused a strong cell-specific pro-inflammatory response and produced a high degree of cell damage that ended with death by lysis (endothelial cells) or apoptosis/lysis (monocytes). The interaction with endothelial cells was stronger than expected and significantly different for both l…
FRI0152 Inflammasomes activation occurs in the inflamed tissues of as patients and drives il-23 expression
2018
Background A growing body of evidences indicate that the aberrant activation of innate immune systems, occurring in genetically predisposed patients, drives inflammatory processes in Ankylosing Spondylitis (AS).1 Objectives Aim of this study was to evaluate the activation and the functional relevance of inflammasome pathways in patients with AS. Methods Intestinal, synovial and bone marrow expression of inflammasome pathways, pyroptosis and IL-1b and IL-18 was evaluated in AS patients. Organic acid extraction was performed on ileal samples as previously described on.2 The expression of the metabolite-sensing receptors GPR43 and GPR109A involved in the regulation of the intestinal inflammaso…
Physico-chimie des lipopolysaccharides et réponse inflammatoire : rôle des lipoprotéines
2014
LPS is a potent bacterial pro-inflammatory agent, consisting of hydrophilic, polysaccharide part and of a lipid A which is considered like active moiety. Nevertheless, the O chain of LPS influences their aggregation in aqueous media. Therefore, our goal has been to determine the role of O chain on the LPS biological and physiopathological effects. Our work was organized according to three main axes, and led to the following findings :- development of a new LPS assay by LC-MS/MS. The combination of this new technique with LAL test allowed us to calculate an inactivation ratio which reflects the ability of host organism to inactivate LPS, especially through their transfer to HDL by PLTP. The …
Monocyte distribution width (MDW) as a screening tool for early detecting sepsis: a systematic review and meta-analysis
2022
Abstract Objectives Monocyte distribution has recently emerged as a promising biomarker of sepsis, especially in acute setting, such as Emergency Department and Intensive Care Unit. This study aimed to evaluate the accuracy of monocyte distribution width (MDW) for early detecting patients with sepsis by performing a systemic review and meta-analysis of published studies. Methods Relevant publications were identified by a systematic literature search on PubMed and Google Scholar from inception to September 07, 2021. Studies were divided into two groups based on the sepsis criteria applied, namely sepsis-2 or sepsis-3. Results Ten studies including 9,475 individuals, of whom 1,370 with sepsis…