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Mechanobiological Evidence for the Control of Neutrophil Activity by Fluid Shear Stress
Published in Jiro Nagatomi, Eno Essien Ebong, Mechanobiology Handbook, 2018
Hainsworth Y. Shin, Xiaoyan Zhang, Ayako Makino, Geert W. Schmid-Schönbein
The central topic of this chapter is the regulation of polymorphonuclear leukocyte (particularly, neutrophil) activity by circulatory hemodynamics-derived mechanical stresses. Neutrophil activation in the microcirculation plays a critical role in the initiation and control of inflammation (definition: a cascade of biological processes by multiple immune and tissue-specific cell types that promote an adaptive response of host tissues to noxious insult) (Medzhitov, 2008). In this respect, neutrophils play an essential role in the acute-stage defense against pathogens (e.g., microorganisms, foreign bodies, and inorganic materials) as well as in the repair and management of tissue damage due to injury. As a consequence of their capacity to express potent antimicrobial and tissue degradative agents during early inflammatory processes, cellular mechanisms must exist to ensure tight regulation of the destructive potential of the polymorphonuclear leukocytes that, if unchecked, may lead to damage to host tissues. Thus, turning off neutrophil inflammatory processes during the resolution stages of wound healing and infection is just as critical as turning on these activities at the time of infection or tissue injury.
Biomaterial Surface Properties
Published in Nihal Engin Vrana, Biomaterials and Immune Response, 2018
Tuğba Endoğan Tanır, Güneş Esendağlı, Eda Ayşe Aksoy
Polymorphonuclear neutrophils (PMN) are the most abundant type of leukocytes in the blood. Even though they have a short life-span, they are a vital part of the immune system. PMNs are the most motile leukocytes with their high capacity to easily travel through the stroma and they are usually the first to reach to the site of injury, especially in the acute phase of inflammation. Neutrophils respond to any type of stress including infections, cancer, trauma, heat changes, sterile inflammation, changes in the oxygen levels and pH and other disorders and disruptions of homeostasis. Similar to other phagocytic cells (i.e., macrophages), neutrophils are indispensable in fighting against extracellular bacteria through phagocytosis, releasing reactive molecules and enzymes to remove the invading microorganisms. In the context of biomaterials, neutrophils are also one of the first cell types that interact with biomaterial surfaces upon implantation.
The State of the Science: Human Health, Toxicology, and Nanotechnology Risks
Published in Jo Anne Shatkin, Nanotechnology, 2017
Cytokines are soluble proteins secreted by macrophages. Once present in the site of infection, they can recruit other cells of the immune system, such as neutrophils, eosinophils, or basophils, into the infected area. Neutrophils are specialized to phagocytize and kill intruders (e.g., pathogens, foreign bodies). They can act as soon as an infection arises, and are the principal phagocytic cell in infected and inflamed tissues. Neutrophils have a short life (4 to 10 hours) and die at the site of infection immediately after attacking a foreign particle. The chemicals released by these cells induce inflammation at the site of infection. Cytokines work as signaling mediators, serving as initial triggers of antibody production. Some tumor necrosis factors (e.g., TNF-a) have been reported in many in vivo and in vitro CNT studies as an indicator of immunological activity, inflammation, and fibrosis. As an example, Chou and colleagues (2008) propose the molecular characterization of SWCNT-induced cytotoxicity in macrophages. In the samples they used, uptake of SWCNTs into macrophages induced oxidative stress in mitochondria and activated nuclear factors and transcription factors (such as NF-κB and AP-1, respectively), which led to large-scale production of cytokines and chemokines. Uptake of SWCNTs also induced the expression of protective and antiapoptotic genes and led to the activation of certain white bloods cells called T or T-lymphocyte cells.
Regulation of stem cell fate and function by using bioactive materials with nanoarchitectonics for regenerative medicine
Published in Science and Technology of Advanced Materials, 2022
Wei Hu, Jiaming Shi, Wenyan Lv, Xiaofang Jia, Katsuhiko Ariga
At the tissue damage site, neutrophils and macrophages are early responsive immune cells. Neutrophils clean up damaged cells and ECM by enzymes and remove cell debris by phagocytosis. Macrophages have multiple phenotypes from pro-inflammatory M1 to anti-inflammatory M2 [142]. After tissue damages, pro-inflammatory cues such as interferon-γ (IFN-γ) and tumour necrosis factor (TNF) can activate M1 macrophages [143]. They can take part in phagocytosis and angiogenesis. However, a prolonged presence of M1 macrophages triggers chronic inflammation and delays tissue repair. M2 macrophages can be activated by cytokines such as interleukin-4 (IL-4), IL-10, IL-13 or IL-33 [144]. They can stabilize angiogenesis and stimulate ECM assembly and remodelling, and thus promote the tissue repair process. However, a prolonged presence of M2 macrophages can result in excessive fibrosis.
Effects of an environmentally relevant PCB-mixture on immune function, clinical chemistry, and thyroid hormone levels in adult female B6C3F1 mice
Published in Journal of Toxicology and Environmental Health, Part A, 2021
Patricia A. Fair, Margie M. Peden-Adams, Meagan A.M. Mollenhauer, Gregory D. Bossart, Deborah E. Keil, Natasha D. White
Complete blood cell counts (CBC) [white blood cells, red blood cells, hemoglobin, packed cell volume, hematocrit, mean corpuscular volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, red blood cell distribution width, mean platelet volume, and platelets] were determined using an automated analyzer (Bayer ADVIA 120, Bayer Diagnostics, Tarrytown, NY). Differential leukocyte counts (neutrophils, lymphocytes, eosinophils, and monocytes), as part of the CBC, were performed by microscopic examination of modified Wright-Giemsa stained blood smears (Bayer Healthcare, Tarrytown, NY). The serum chemistry analytes (glucose, total protein, calcium, BUN, alanine aminotransferase (ALT), aspartate aminotransferase (AST), amylase, total bilirubin, and creatinine phosphokinase (CPK) were measured with an automated analyzer (Roche Hitachi 917, Indianapolis, IN). Other serum analytes were not measured including sodium, potassium, chloride, bicarbonate, iron, uric acid, cholesterol, triglycerides, anion gap, creatinine, albumin, globulin, albumin/globulin, magnesium, γ- glutamyltransferase, and total iron-binding capacity due to low serum volumes resulting in small sample sizes from 1 to 3 for some treatment groups.
Acute toxicity and health effect of perfluoroisobutyronitrile on mice: a promising substitute gas-insulating medium to SF6
Published in Journal of Environmental Science and Health, Part A, 2020
Xiaoxing Zhang, Fanchao Ye, Yi Li, Shuangshuang Tian, Baojuan Xie, Yadong Gao, Song Xiao
Table 3 shows the blood cell test results of mice after exposure. It can be found that the lymphocytes percentage of mice that died at a concentration of 1202 ppm significantly decreased and the neutrophils percentage increased significantly, which are all deviated from the reference value. Neutrophils belong to a type of white blood cells that play an important role in the immune system. A high percentage of neutrophils are common in acute inflammation. Lymphocytes can produce and carry antibodies and prevent viral infections. The decrease in lymphocyte percentage is common in immunodeficiency diseases, which indicates that acute inhalation of C4F7N gas within 4 h will cause inflammation and decline of immune system function. In addition, the number of red blood cells and hemoglobin that transport oxygen through blood in the animal in the dead mice at 1202 ppm is high, which is due to the impaired heart and lung function of the mice (the clinical manifestation is that the mice have shortness of breath).