scholarly journals Phagocyte extracellular traps in children with neutrophilic airway inflammation

2021 ◽  
pp. 00883-2020
Author(s):  
Paul T. King ◽  
Lovisa Dousha ◽  
Nadeene Clarke ◽  
Jennifer Schaefer ◽  
Rosemary Carzino ◽  
...  
Keyword(s):  
Airway Inflammation ◽  
Lung Infection ◽  
Functional Assays ◽  
Extracellular Traps ◽  
Excess Production ◽  
Dnase 1 ◽  
The Mean ◽  
Extracellular Trap ◽  
Alpha 1 Antitrypsin

Childhood lung infection is often associated with prominent neutrophilic airway inflammation and excess production of proteases such as neutrophil elastase (NE). The mechanisms responsible for this inflammation are not well understood. One potentially relevant pathway is the production of extracellular traps by neutrophils (NETs) and macrophages (METs). The aim of this study was to measure NET and MET expression in children and the effect of deoxyribonculease (DNase) 1 and alpha-1 antitrypsin (AAT) on this process.We studied 76 children (median age of 4.0 years) with cystic fibrosis (CF) or chronic cough who underwent investigational bronchoscopy. NETs, METs and NE activity in bronchoalveolar lavage (BAL) samples were measured using confocal microscopy and functional assays. The effects of DNase 1 and AAT on NET/MET expression and NE activity were examined in vitro.Both subject groups had airway neutrophilia with prominent BAL production of NETs with NE co-expression; the mean %±standard error of the mean of neutrophils expressing NETs in the CF group was 23.3±2.8% and in the non-CF group was 28.4±3.9%. NET expression was higher in subjects who had detectable NE activity (p≤0.0074). The percentage of macrophages expressing METs in the CF group was 10.7±1.2% and in the non-CF group was 13.2±1.9%. DNase 1 decreased NET/MET expression (p<0.0001), but increased NE activity (p≤0.0137). The combination of AAT and DNase 1 reduced NE activity (p≤0.0049).We observed prominent extracellular trap formation in symptomatic children with and without CF. This innate inflammatory response was down-regulated by a combination of currently available therapeutics.

scholarly journals Synergistic anticryptosporidial potential of the combination alpha-1-antitrypsin and paromomycin.

1997 ◽  
Vol 41 (9) ◽  
pp. 2006-2008 ◽  
Author(s):  
J R Forney ◽  
S Yang ◽  
M C Healey
Keyword(s):  
Inhibitory Concentration ◽  
Combined Treatment ◽  
Serine Protease Inhibitor ◽  
Synergistic Activity ◽  
Combined Treatments ◽  
Treatment Groups ◽  
The Mean ◽  
Alpha 1 Antitrypsin ◽  
Concentration Indices

The combined effect of the serine protease inhibitor alpha-1-antitrypsin (AAT) and the aminoglycoside paromomycin on Cryptosporidium parvum infection in vitro was investigated. AAT and paromomycin were mixed with C. parvum oocysts as either single or combined treatments and used to inoculate epithelial cell cultures. Single- and combined-treatment groups had significantly lower (P < 0.01) parasite numbers than untreated controls. The mean fractional inhibitory concentration indices suggested significant synergistic activity.

scholarly journals Neutrophil extracellular traps promote tPA-induced brain hemorrhage via cGAS in mice with stroke

Blood ◽  
2021 ◽  
Author(s):  
Ranran Wang ◽  
Yuanbo Zhu ◽  
Zhongwang Liu ◽  
Luping Chang ◽  
Xiaofei Bai ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Thrombolytic Therapy ◽  
Clinical Problem ◽  
Neutrophil Extracellular Traps ◽  
Artery Occlusion ◽  
Type I ◽  
Brain Hemorrhage ◽  
Extracellular Traps ◽  
Dnase 1

Intracerebral hemorrhage associated with thrombolytic therapy with tissue plasminogen activator (tPA) in acute ischemic stroke continues to present a major clinical problem. Here, we report that infusion of tPA resulted in a significant increase in markers of neutrophil extracellular traps (NETs) in the ischemic cortex and plasma of mice subjected to photothrombotic middle cerebral artery occlusion. Peptidylarginine deiminase 4 (PAD4), a critical enzyme for NET formation, is also significantly upregulated in the ischemic brains in tPA-treated mice. Blood-brain barrier (BBB) disruption following ischemic challenge in an in vitro model of BBB was exacerbated after exposure to NETs. Importantly, disruption of NETs by DNase 1 or inhibition of NET production by PAD4 deficiency restored tPA-induced loss of BBB integrity and consequently decreased tPA-associated brain hemorrhage after ischemic stroke. Furthermore, either DNase 1 or PAD4 deficiency reversed tPA-mediated upregulation of the DNA sensor cyclic GMP-AMP (cGAMP) synthase (cGAS). Administration of cGAMP after stroke abolished DNase 1-mediated downregulation of the STING pathway and type I interferon (IFN) production, and blocked the antihemorrhagic effect of DNase 1 in tPA-treated mice. We also show that tPA-associated brain hemorrhage after ischemic stroke was significantly reduced in cGas-/- mice. Collectively, these findings demonstrate that NETs significantly contribute to tPA-induced BBB breakdown in ischemic brain, and suggest that targeting NETs or cGAS may ameliorate thrombolytic therapy for ischemic stroke by reducing tPA-associated hemorrhage.

scholarly journals Antibodies Against Pseudomonas aeruginosa Alkaline Protease Directly Enhance Disruption of Neutrophil Extracellular Traps Mediated by This Enzyme

2021 ◽  
Vol 12 ◽  
Author(s):  
Chendi Jing ◽  
Chenghua Liu ◽  
Yu Liu ◽  
Ruli Feng ◽  
Run Cao ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Alkaline Protease ◽  
Chronic Infection ◽  
Active Sites ◽  
Neutrophil Extracellular Traps ◽  
Lung Infection ◽  
Bacterial Burden ◽  
Extracellular Traps

Extracellular traps released by neutrophils (NETs) are essential for the clearance of Pseudomonas aeruginosa. Alkaline protease (AprA) secreted by P. aeruginosa negatively correlates with clinical improvement. Moreover, anti-AprA in patients with cystic fibrosis (CF) can help identify patients with aggressive forms of chronic infection. However, the mechanism underlying the clinical outcomes remains unclear. We demonstrated that aprA deficiency in P. aeruginosa decreased the bacterial burden and reduced lung infection. AprA degraded NET components in vitro and in vivo but did not affect NET formation. Importantly, antibodies induced by AprA acted as an agonist and directly enhanced the degrading activities of AprA. Moreover, antisera from patients with P. aeruginosa infection exhibited antibody-dependent enhancement (ADE) similar to that of the antibodies we prepared. Our further investigations showed that the interaction between AprA and the specific antibodies might make the enzyme active sites better exposed, and subsequently enhance the recognition of substrates and accelerate the degradation. Our findings revealed that AprA secreted by P. aeruginosa may aggravate infection by destroying formed NETs, an effect that was further enhanced by its antibodies.

scholarly journals Bovine neutrophils release extracellular traps and cooperate with macrophages in Mycobacterium avium subsp. paratuberculosis clearance

2021 ◽  
Author(s):  
I Ladero-Auñon ◽  
E Molina ◽  
A Holder ◽  
J Kolakowski ◽  
H Harris ◽  
...  
Keyword(s):  
Mycobacterium Avium ◽  
Inflammatory Reaction ◽  
Cell Types ◽  
Mycobacterial Infection ◽  
Cell Contact ◽  
Target Cells ◽  
Killing Effect ◽  
Extracellular Traps ◽  
Extracellular Trap

AbstractMycobacterium avium subsp. paratuberculosis (Map) is the underlying pathogen causing bovine paratuberculosis (PTB), an enteric granulomatous disease that mainly affects ruminants and for which an effective treatment is needed. Macrophages are the primary target cells for Map, which survives and replicates intracellularly by inhibiting phagosome maturation. Neutrophils are present at disease sites during the early stages of the infection, but seem to be absent in the late stage, in contrast to healthy tissue. Although neutrophil activity has been reported to be impaired following Map infection, their role in PTB pathogenesis has not been fully defined. Neutrophils are capable of releasing extracellular traps consisting of extruded DNA and proteins that immobilize and kill microorganisms, but this mechanism has not been evaluated against Map. Our main objective was to study the interaction of neutrophils with macrophages during an in vitro mycobacterial infection. For this purpose, neutrophils and macrophages from the same animal were cultured alone or together in the presence of Map or Mycobacterium bovis Bacillus-Calmette-Guérin (BCG). Extracellular trap release, mycobacteria killing as well as IL-1β and IL-8 release were assessed. Extracellular trap formation was highest in neutrophils against Map in the presence of macrophages, but without direct cell contact, indicating a paracrine activation. Macrophages were extremely efficient at killing BCG, but ineffective at killing Map. In contrast, neutrophils showed similar killing rates for both mycobacteria. Co-cultures infected with Map showed the expected killing effect of combining both cell types, whereas co-cultures infected with BCG showed a potentiated killing effect beyond the expected one, indicating a potential synergistic cooperation. In both cases, IL-1β and IL-8 levels were lower in co-cultures, suggestive of a reduced inflammatory reaction. These data indicate that cooperation of both cell types can be beneficial in terms of decreasing the inflammatory reaction while the effective elimination of Map can be compromised. These results suggest that neutrophils are effective at Map killing and can exert protective mechanisms against Map that seem to fail during PTB disease after the arrival of macrophages at the infection site.

scholarly journals Immunoregulation of Neutrophil Extracellular Trap Formation by Endothelial-Derived p33 (gC1q Receptor)

2017 ◽  
Vol 10 (1) ◽  
pp. 30-43 ◽  
Author(s):  
Ariane Neumann ◽  
Praveen Papareddy ◽  
Johannes Westman ◽  
Ole Hyldegaard ◽  
Johanna Snäll ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Enzymatic Activity ◽  
Streptococcus Pyogenes ◽  
Neutrophil Extracellular Traps ◽  
Neutrophil Extracellular Trap ◽  
Defence Mechanism ◽  
Extracellular Traps ◽  
Molecular Pattern ◽  
Extracellular Trap

The formation of neutrophil extracellular traps (NETs) is a host defence mechanism, known to facilitate the entrapment and growth inhibition of many bacterial pathogens. It has been implicated that the translocation of myeloperoxidase (MPO) from neutrophilic granules to the nucleus is crucial to this process. Under disease conditions, however, excessive NET formation can trigger self-destructive complications by releasing pathologic levels of danger-associated molecular pattern molecules (DAMPs). To counteract such devastating immune reactions, the host has to rely on precautions that help circumvent these deleterious effects. Though the induction of DAMP responses has been intensively studied, the mechanisms that are used by the host to down-regulate them are still not understood. In this study, we show that p33 is an endothelial-derived protein that has the ability to annul NET formation. We found that the expression of human p33 is up-regulated in endothelial cells upon infections with Streptococcus pyogenes bacteria. Using tissue biopsies from a patient with streptococcal necrotising fasciitis, we monitored co-localisation of p33 with MPO. Further in vitro studies revealed that p33 is able to block the formation of DAMP-induced NET formation by inhibiting the enzymatic activity of MPO. Additionally, mice challenged with S. pyogenes bacteria demonstrated diminished MPO activity when treated with p33. Together, our results demonstrate that host-derived p33 has an important immunomodulating function that helps to counterbalance an overwhelming DAMP response.

Influence of Platelet Membrane Sialic Acid and Platelet-Associated IgG on Ageing and Sequestration of Blood Platelets in Baboons

1993 ◽  
Vol 70 (04) ◽  
pp. 676-680 ◽  
Author(s):  
H F Kotzé ◽  
V van Wyk ◽  
P N Badenhorst ◽  
A du P Heyns ◽  
J P Roodt ◽  
...  
Keyword(s):  
Sialic Acid ◽  
Life Span ◽  
Blood Platelets ◽  
Senescent Cell ◽  
Platelet Membrane ◽  
Antigen Complex ◽  
The Mean ◽  
Aggregation Of Platelets

SummaryPlatelets were isolated from blood of baboons and treated with neuraminidase to remove platelet membrane sialic acid, a process which artificially ages the platelets. The platelets were then labelled with 111In and their mean life span, in vivo distribution and sites of Sequestration were measured. The effect of removal of sialic acid on the attachment of immunoglobulin to platelets were investigated and related to the Sequestration of the platelets by the spleen, liver, and bone marrow. Removal of sialic acid by neuraminidase did not affect the aggregation of platelets by agonists in vitro, nor their sites of Sequestration. The removal of 0.51 (median, range 0.01 to 2.10) nmol sialic acid/108 platelets shortened their life span by 75 h (median, range 0 to 132) h (n = 19, p <0.001), and there was an exponential correlation between the shortening of the mean platelet life span and the amount of sialic acid removed. The increase in platelet-associated IgG was 0.112 (median, range 0.007 to 0.309) fg/platelet (n = 25, p <0.001) after 0.79 (median, range 0.00 to 6.70) nmol sialic acid/108 platelets was removed (p <0.001). There was an exponential correlation between the shortening of mean platelet life span after the removal of sialic acid and the increase in platelet-associated IgG. The results suggest that platelet membrane sialic acid influences ageing of circulating platelets, and that the loss of sialic acid may have exposed a senescent cell antigen that binds IgG on the platelet membrane. The antibody-antigen complex may then provide a signal to the macrophages that the platelet is old, and can be phagocytosed and destroyed.

Characterization of the Serum a1-Antitripsine Level in Primary Spontaneous Pneumotorax Patients

2018 ◽  
Vol 69 (9) ◽  
pp. 2591-2593
Author(s):  
Cristina Grigorescu ◽  
Liviu Ciprian Gavril ◽  
Laura Gavril ◽  
Tiberiu Lunguleac ◽  
Bogdan Mihnea Ciuntu ◽  
...  
Keyword(s):  
Serum Level ◽  
Pulmonary Emphysema ◽  
Spontaneous Pneumothorax ◽  
Antitrypsin Deficiency ◽  
Alpha 1 Antitrypsin Deficiency ◽  
Alpha 1 Antitrypsin ◽  
Determining Factor

Diagnosis of primary or idiopathic spontaneous pneumothorax is one of exclusion, and in fact defines an entity that may have a difficult or impossible cause to be highlighted by current means, we consider it appropriate to study these etiopathogenic aspects. There is a definite association between alpha-1 antitrypsin deficiency and pulmonary emphysema and indirect spontaneous pneumothorax secondary to an emphysematous pulmonary lesion. Dose of alpha-1 antitrypsin is an immunoturbinimetric method for in vitro determination of alpha-1 antitrypsin in human serum and plasma. This product is calibrated to be used for the Daytona RX analyzer. The serum level of alpha-1-antitrypsin is not a determining factor in the postoperative evolution characterized by the interval until air loss disappears, but certainly exerts some influence, the exact level of which remains to be determined.

The Safety and Antimicrobial Properties of Stabilized Hypochlorous Acid in Acetic Acid Buffer for the Treatment of Acute Wounds—a Human Pilot Study and In Vitro Data

2021 ◽  
pp. 153473462110156
Author(s):  
Ewa A. Burian ◽  
Lubna Sabah ◽  
Klaus Kirketerp-Møller ◽  
Elin Ibstedt ◽  
Magnus M. Fazli ◽  
...  
Keyword(s):  
Pilot Study ◽  
Hypochlorous Acid ◽  
Treatment Time ◽  
Donor Site ◽  
Antimicrobial Properties ◽  
Prolonged Treatment ◽  
Wound Irrigation ◽  
The Mean ◽  
And Performance

Acute wounds may require cleansing to reduce the risk of infection. Stabilized hypochlorous acid in acetic buffer (HOCl + buffer) is a novel wound irrigation solution with antimicrobial properties. We performed a first-in-man, prospective, open-label pilot study to document preliminary safety and performance in the treatment of acute wounds. The study enrolled 12 subjects scheduled for a split-skin graft transplantation, where the donor site was used as a model of an acute wound. The treatment time was 75 s, given on 6 occasions. A total of 7 adverse events were regarded as related to the treatment; all registered as pain during the procedure for 2 subjects. One subject had a wound infection at the donor site. The mean colony-forming unit (CFU) decreased by 41% after the treatment, and the mean epithelialization was 96% on both days 14 (standard deviation [SD] 8%) and 21 (SD 10%). The study provides preliminary support for the safety, well-tolerance, and efficacy of HOCl + buffer for acute wounds. The pain was frequent although resolved quickly. Excellent wound healing and satisfying antimicrobial properties were observed. A subsequent in vitro biofilm study also indicated good antimicrobial activity against Pseudomonas aeruginosa with a 96% mean reduction of CFU, when used for a treatment duration of 15 min ( P < .0001), and a 50% decrease for Staphylococcus aureus ( P = .1010). Future larger studies are needed to evaluate the safety and performance of HOCl + buffer in acute wounds, including the promising antimicrobial effect by prolonged treatment on bacterial biofilms.

scholarly journals Formulation and in vitro evaluation of self-nanoemulsifying liquisolid tablets of furosemide

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Lena Dalal ◽  
Abdul Wahab Allaf ◽  
Hind El-Zein
Keyword(s):  
Theoretical Model ◽  
Castor Oil ◽  
In Vivo Studies ◽  
Coating Materials ◽  
Peg 400 ◽  
The Mean ◽  
Usp Apparatus ◽  
Solid System

AbstractSelf-nanoemulsifying drug delivery systems (SNEDDS) were used to enhance the dissolution rate of furosemide as a model for class IV drugs and the system was solidified into liquisolid tablets. SNEDDS of furosemide contained 10% Castor oil, 60% Cremophor EL, and 30% PEG 400. The mean droplets size was 17.9 ± 4.5 nm. The theoretical model was used to calculate the amounts of the carrier (Avicel PH101) and coating materials (Aerosil 200) to prepare liquisolid powder. Carrier/coating materials ratio of 5/1 was used and Ludipress was added to the solid system, thus tablets with hardness of 45 ± 2 N were obtained. Liquisolid tablets showed 2-folds increase in drug release as compared to the generic tablets after 60 min in HCl 0.1 N using USP apparatus-II. Furosemide loaded SNEDDS tablets have great prospects for further in vivo studies, and the theoretical model is useful for calculating the adequate amounts of adsorbents required to solidify these systems.

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