Reduced chemotactic migration of polymorphonuclear neutrophil (PMN) in sepsis patients leads to decreased bacterial clearance and accelerates the progression of sepsis disease. Quantification of PMN chemotaxis in sepsis patients can help characterize the immune health of sepsis patients. Microfluidic microarrays have been widely used for cell chemotaxis analysis because of the advantages of low reagent consumption, near-physiological environment, and visualization of the migration process. Currently, the study of PMN chemotaxis using microfluidic chips is mainly limited by the cumbersome cell separation operation and low throughput of microfluidic chips. In this paper, we first designed an inertial cell sorting chip to achieve label-free separation of the two major cell types by using the basic principle that leukocytes (mainly granulocytes, lymphocytes and monocytes) and erythrocytes move to different positions of the spiral microchannel when they move in the spiral microchannel under different strength of inertial force and Dean's resistance. Subsequently, in this paper, we designed a multi-channel cell migration chip and constructed a microfluidic PMN inertial label-free sorting and chemotaxis analysis platform. The inertial cell sorting chip separates leukocyte populations and then injects them into the multi-channel cell migration chip, which can complete the chemotaxis test of PMN to chemotactic peptide (fMLP) within 15 min. The remaining cells, such as monocytes with slow motility and lymphocytes that require pre-activation with proliferative culture, do not undergo significant chemotactic migration. The test results of sepsis patients ( n=6) and healthy volunteers ( n=3) recruited in this study showed that the chemotaxis index (CI) and migration velocity ( v) of PMN from sepsis patients were significantly weaker than those from healthy volunteers. In conclusion, the microfluidic PMN inertial label-free sorting and chemotaxis analysis platform constructed in this paper can be used as a new tool for cell label-free sorting and migration studies.
Humans ; Chemotaxis ; Neutrophils/metabolism* ; Microfluidics ; Cell Movement ; Sepsis/metabolism*

OBJECTIVES: To investigate the expression changes of annexin A1 （ANXA1） during the process of skin incision healing, and to explore its expression and function during skin injury repair. METHODS: The skin injury model of mice was prepared, and skin tissues of the controls and the injured group at 6 h, 12 h, 1 d, 3 d, 5 d, 7 d, 10 d and 14 d after injuries were taken. The morphological changes of the wound were observed by hematoxylin-eosin （HE） staining, and the expression of ANXA1 was detected by immunohistochemistry （IHC） and Western blotting. RESULTS: HE staining showed normal healing of skin wounds. IHC results revealed that ANXA1 was expressed in the epidermis, hair follicle, sebaceous gland and vascular endothelium. In the injured group, the expression of ANXA1 was enhanced in epidermis and skin appendages around the wound 6-12 h after injury, and ANXA1 was also highly expressed in neutrophils and a small number of mononuclear cells. ANXA1 was mainly positively expressed in monocytes, neovascular endothelial cells and fibroblasts, and small amount of fibroblasts at 1-3 d, 5-10 d, and 14 d after injury, respectively. Western blotting showed that, compared with the controls, the expression of ANXA1 was significantly increased at 6 h after injury, peaked at 1 d, and then decreased gradually in the injured group. CONCLUSIONS ANXA1 may be involved in the regulation of skin damage repair, with time-dependent expression during skin wound healing, and thus is expected to be a biological marker for inferring the wound formation time.
Animals ; Annexin A1/metabolism* ; Fibroblasts ; Mice ; Neutrophils ; Skin ; Wound Healing

Neutrophils are predominant leukocytes in the circulation, which are essential for killing invading pathogens via the activation of effector responses and the production of reactive oxygen species (ROS), also named as "oxidative burst." When infected, activated neutrophils fight bacteria, fungi, and viruses through oxidative burst, phagocytosis, degranulation, and the production of neutrophil extracellular traps (NETs) in a neutrophil death process named as "NETosis" (Mutua and Gershwin, 2021). NETs, consisting of DNA fibers decorated with modified histones and numerous antimicrobial proteins from cytoplasmic granules and the nucleus, can either be beneficial or detrimental (Mutua and Gershwin, 2021). Several pathways can lead to this death process. In response to various stimuli, NETosis traps and clears pathogens, facilitating phagocytosis by other neutrophils and phagocytes. However, excessive NETosis often results in disease due to increasing the pro-inflammatory response and perpetuating the inflammatory condition (Hellebrekers et al., 2018; Hidalgo et al., 2019; Klopf et al., 2021). Accordingly, inhibiting aberrant NETosis may alleviate the severity of various autoimmune and inflammatory diseases.
DNA ; Extracellular Traps/metabolism* ; Neutrophils/metabolism* ; Reactive Oxygen Species/metabolism* ; Respiratory Burst

Muscle involvement in acute febrile neutrophilic dermatosis is uncommon. Herein, we report a case of acute febrile neutrophilic myositis, without cutaneous involvement, as the first manifestation of acute myeloid leukemia. The patient was a 35-year-old male, referred due to painful swelling of the left upper arm and fever. The overlying skin looked normal, and a muscle biopsy revealed dense infiltrates, predominantly composed of mature neutrophils, edema and tissue necrosis. All culture reports were negative, and he was finally diagnosed as having acute febrile neutrophilic myositis, associated with acute myeloid leukemia. Corticosteroid treatment resulted in the progressive regression of the fever, myalgia and swelling.
Neutrophils/*metabolism ; Myositis/*etiology/metabolism ; Male ; Leukemia, Myelocytic, Acute/*diagnosis ; Humans ; Fever/etiology ; Adult

OBJECTIVETo explore the effect of substance P (SP) on the functional proteins on plasma membrane of neutrophil (Np).

METHODThe response of Np to SP was examined by measuring the level of respiratory burst, the activities of ACP and ALP, the fluoroscopy intensity of CR3, CD45 and FM-LP.

RESULTSIt was found that SP could increase respiratory burst of Np, decrease the activity of acid phosphatase (ACP), but had no effect on alkaline phosphatase (ALP). SP could also promote the amount of CD45, complement receptor type 3 (CR3) and N-Formyl-Met-Leu-Phe (FMLP) receptors.

CONCLUSIONThe results showed that the effects of SP on functional proteins in human Np membrane were universality and diversity. It implied that SP could affect various inflammation responses in Np.

Acid Phosphatase ; metabolism ; Humans ; Membrane Proteins ; physiology ; Neutrophils ; metabolism ; Respiratory Burst ; Substance P ; pharmacology

OBJECTIVETo investigate the influence of neonatal maturity on active oxygen metabolism in neutrophils and possible causes of a high susceptibility to bacterial infection in preterm infants.

METHODSThirty-five preterm infants born at a gestation age of 26-32 weeks (< or =32 weeks group, n=15) and at 33-36 weeks (> 32 weeks group, n=20) and 23 full-term infants (control group) were enrolled in this study. The samples of whole cord blood from the two preterm groups and the control group were stimulated in vitro with live bacteria,Staphylococcus aureus ( S. aureus) and Escherichia coli (E. coli) and stained with hydroethedine, an indicator of superoxide. The percentage of neutrophils which produced superoxide and the mean fluorescence intensity for superoxide production were measured by flow cytometry. The incidence of bacterial infection during hospital stay was compared between the two preterm groups.

RESULTSUnder S. aureus or E. coli stimulation, the percentage of neutrophils which produced superoxide in the < or =32 weeks group was significantly lower than that of the > 32 weeks group and the control group (P < 0.01). The percentage of neutrophils which produced superoxide was closely related to gestational age in preterm infants ( y=2.66 x, P < 0.01).There were no significant differences in the blood level of superoxide production in neutrophils among the three groups. The incidence of bacterial infection during hospital stay in the < or =32 weeks group (40%) was significantly higher than that the > 32 weeks group (10%) (P < 0.05).

CONCLUSIONSThe capability of active oxygen metabolism in neutrophils was significantly related to the gestational age in preterm infants. The decreased capability of active oxygen metabolism might be contributed to a higher susceptibility to bacterial infection in preterm infants.

Disease Susceptibility ; Gestational Age ; Humans ; Infant, Newborn ; Infant, Premature ; immunology ; Neutrophils ; metabolism ; Superoxides ; metabolism

Humans ; Computational Biology ; Neutrophils/metabolism* ; Sepsis/metabolism* ; Signal Transduction/genetics* ; Immunosuppression Therapy ; Gene Expression Profiling

OBJECTIVEAsthma and chronic obstructive pulmonary disease (COPD) are representative chronic inflammatory airway diseases responsible for a considerable burden of disease. In this article, we reviewed the relationship between neutrophil extracellular traps (NETs) and chronic inflammatory airway diseases.

DATA SOURCESArticles published up to January 1, 2017, were selected from the PubMed, Ovid Medline, Embase databases, with the keywords of "asthma" or "pulmonary disease, chronic obstructive", "neutrophils" and "extracellular traps."

STUDY SELECTIONArticles were obtained and reviewed to analyze the role of NETs in asthma and COPD.

RESULTSNETs are composed of extracellular DNA, histones, and granular proteins, which are released from activated neutrophils. Multiple studies have indicated that there are a large amount of NETs in the airways of asthmatics and COPD patients. NETs can engulf and kill invading pathogens in the host. However, disordered regulation of NET formation has shown to be involved in the development of asthma and COPD. An overabundance of NETs in the airways or lung tissue could cause varying degrees of damage to lung tissues by inducing the death of human epithelial and endothelial cells, and thus resulting in impairing pulmonary function and accelerating the progress of the disease.

CONCLUSIONSExcessive NETs accumulate in the airways of asthmatics and COPD patients. Although NETs play an essential role in the innate immune system against infection, excessive components of NETs can cause lung tissue damage and accelerate disease progression in asthmatics and COPD patients. These findings suggest that administration of NETs could be a novel approach to treat asthma and COPD. Mechanism studies, clinical practice, and strategies to regulate neutrophil activation or directly interrupt NET function in asthmatics and COPD patients are desperately needed.

Animals ; Asthma ; metabolism ; pathology ; Extracellular Traps ; metabolism ; physiology ; Humans ; Neutrophils ; metabolism ; pathology ; Pulmonary Disease, Chronic Obstructive ; metabolism ; pathology

P-selectin engagement of P-selectin glycoprotein ligand-1 (PSGL-1) causes circulating leukocytes to roll on and adhere to the vascular surface, and mediates intracellular calcium flux, a key but unclear event for subsequent arresting firmly at and migrating into the infection or injured tissue. Using a parallel plate flow chamber technique and intracellular calcium ion detector (Fluo-4 AM), the intracellular calcium flux of firmly adhered neutrophils on immobilized P-selectin in the absence of chemokines at various wall shear stresses was investigated here in real time by fluorescence microscopy. The results demonstrated that P-selectin engagement of PSGL-1 induced the intracellular calcium flux of firmly adhered neutrophils in flow, increasing P-selectin concentration enhanced cellular calcium signaling, and, force triggered, enhanced and quickened the cytoplasmic calcium bursting of neutrophils on immobilized P-selectin. This P-selectin-induced calcium signaling should come from intracellular calcium release rather than extracellular calcium influx, and be along the mechano-chemical signal pathway involving the cytoskeleton, moesin and Spleen tyrosine kinase (Syk). These results provide a novel insight into the mechano-chemical regulation mechanism for P-selectin-induced calcium signaling of neutrophils in flow.
Calcium Signaling ; Female ; Humans ; Male ; Membrane Glycoproteins ; metabolism ; Neutrophils ; metabolism ; P-Selectin ; metabolism ; Stress, Mechanical ; Syk Kinase ; metabolism

Malignant hematologic disease with sepsis has been characterized by high mortality and difficulty in diagnosis at early stage. A good biomarker may help to improve the accuracy of diagnosis and to reduce the mortality rate. In the early diagnosis of sepsis, neutrophil CD64 expression is a better candidate for biomarker rather than C-reactive proteins. Moreover, neutrophil CD64 expression is also helpful for assessing the severity of infection and prognosis of disease. Unfortunately, there are few studies of neutrophil CD64 expression on the early diagnosis of malignant hematologic diseases. This review focuses on the advantages, limitations, feasibilities and progresses of neutrophil CD64 expression in the early diagnosis of infection in malignant hematologic diseases in this paper.
Biomarkers ; metabolism ; Early Diagnosis ; Hematologic Diseases ; complications ; Humans ; Neutrophils ; metabolism ; Prognosis ; Receptors, IgG ; metabolism ; Sepsis ; complications ; diagnosis