scholarly journals Circulating Neutrophil Extracellular Traps in the Pathogenesis of Acute Chest Syndrome of Sickle Cell Disease

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 3556-3556
Author(s):  
Ravi Vats ◽  
Egemen Tutuncuoglu ◽  
Jesus Tejero ◽  
Cheryl A Hillery ◽  
Mark T Gladwin ◽  
...  

Introduction: Acute chest syndrome (ACS) is a type of acute lung injury and among the primary reasons for mortality and morbidity among Sickle Cell Disease (SCD) patients. Although epidemiologic evidence suggests that vaso-occlusion in the lung may serve as an antecedent to ACS, the cellular, molecular and biophysical mechanism of ACS is incompletely understood. Our recent findings revealed that the lung vaso-occlusion is enabled by the entrapment of embolic neutrophil-platelet aggregates in the pulmonary arterioles of transgenic humanized SCD mice. Recent evidence also suggests a role for neutrophil extracellular traps (NETs) in ACS. NETs are web-like structures of decondensed nuclear DNA decorated with citrullinated-histones (H3-cit) and neutrophil granule proteins. Interestingly, circulating nucleosomes and NETs fragments are elevated in SCD patient blood and the levels correlate with onset of ACS, however, the molecular mechanism that promotes generation of circulating NETs and the role of circulating NETs in promoting ACS remains poorly understood. Materials and Methods: Townes knock-in humanized SS (hα/hα:βS/βS) and AS (hα/hα:βA/βS) mice were used as SCD and control mice, respectively. SS and AS mice were intravenously (IV) administered 10 µmole/kg Oxy-Hb followed by Sytox orange, FITC-dextran or fluorescent anti-mouse mAbs against Ly6G, CD49b, H3cit, and neutrophil elastase for in vivo visualization of extracellular DNA, blood vessels, neutrophils, platelets and NETs, respectively. Pulmonary microcirculation was monitored using multi-photon-excitation enabled quantitative fluorescence intravital lung microscopy (qFILM). Results and Discussion: IV Oxy-Hb triggered the occlusion of pulmonary arterioles by neutrophil-platelet aggregates leading to loss of pulmonary blood flow in SCD but not control mice. Surprisingly, pulmonary vaso-occlusion in SCD mice was accompanied by the arrival of circulating cell free DNA (CFD) and NETs fragments into the pulmonary circulation. The cell free DNA (CFD) and NETs fragments entered the lung through the arterial circulation suggesting that they originated outside of lung. These cell free DNA (CFD) and NETs fragments contributed to lung vaso-occlusion and injury by promoting neutrophil-platelet aggregation in the lung arterioles. Conclusion: These findings reveal for the first time that circulating cell free DNA (CFD) and NETs fragments originating outside of lung contribute to pathogenesis of ACS. Currently, experiments are underway to identify the innate immune pathways that promote circulating NETs dependent lung injury in SCD. Disclosures Gladwin: Globin Solutions, Inc: Patents & Royalties: Provisional patents for the use of recombinant neuroglobin and heme-based molecules as antidotes for CO poisoning; United Therapeutics: Patents & Royalties: Co-inventor on an NIH government patent for the use of nitrite salts in cardiovascular diseases ; Bayer Pharmaceuticals: Other: Co-investigator.

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 2085-2085
Author(s):  
Yvonne Daniel ◽  
Julia Van Campen ◽  
Lee Silcock ◽  
Michael Yau ◽  
Joo Wook Ahn ◽  
...  

Sickle cell disease (SCD) is the most common genetic haematological disorder worldwide. Around 300.000 affected infants are born every year, including at least 1000 in the United States. Prenatal diagnosis is currently carried out using amniotic fluid or chorionic villus sampling. These invasive procedures are perceived to have a small risk of miscarriage. The availability of non-invasive prenatal diagnosis (NIPD) is predicted to increase uptake of prenatal diagnosis for SCD, as it has no perceived miscarriage risk. NIPD may also be more readily implemented than invasive prenatal diagnosis in the low-resource countries in which SCD is the most prevalent. However, accurate NIPD of autosomal recessive disorders such as sickle cell disease has proven challenging as this requires detection of fetal inheritance of a maternal allele from a mixed maternal-fetal pool of cell-free DNA. We report the development of a targeted massively parallel sequencing assay for the NIPD of fetal SCD using cell-free fetal DNA from maternal plasma. No paternal or previous offspring samples were required. 44 clinical samples were analysed, including 37 plasma samples from pregnant SCD carriers and 7 plasma samples from women with SCD due to Hb SC. We used a relative mutation dosage based approach for the 37 samples from maternal SCD carriers (Hb AS or Hb AC), integrating Unique Molecular Identifiers (UMIs) into the analysis to improve the accuracy of wildtype and mutant allele counts. We used a separate wildtype allele detection approach for the 7 samples from women with compound heterozygous SCD, in whom the detection of wildtype cell-free DNA indicates the presence of a carrier fetus. The success of the assay was evaluated by comparing results with the established fetal sickle status as determined through either invasive prenatal diagnosis or newborn screening. During development, two key factors improved the accuracy of the results: i) Selective analysis of only smaller cell-free DNA fragments enhanced the fetal fraction for all samples, with greater effects observed in samples from earlier gestations. This approach improved diagnostic accuracy: for 3 out of 44 samples, the genotype was inconclusive or incorrect before size selection, but correct after size selection. ii) Modifications to DNA fragment hybridisation capture optimised the diversity of Unique Molecular Identifier-tagged molecules analysed. This led to improvements in the results obtained for 5 samples, with 3 previously inconclusive samples correctly called and 2 previously discrepant results moved into the inconclusive range. In total, 37 results were concordant with the established fetal sickle status; this included 30/37 samples from carrier women and 7/7 samples from women with sickle cell disease due to Hb SC. The remaining 7 carrier samples gave an inconclusive result, which for 3 samples was attributed to a low fetal fraction. Samples from as early as 8 weeks gestation were successfully genotyped. There were no false positive or false negative results. This study is the largest to use NGS-based NIPD on clinical plasma samples from pregnancies at risk of SCD. Efforts to validate the assay on a larger sample cohort and to reduce the inconclusive rate are warranted. This study shows that NIPD for SCD is approaching clinical utility and has the potential to provide increased choice to women with pregnancies at risk of sickle cell disease. Disclosures Silcock: Nonacus Ltd.: Employment.


Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 2113-2113 ◽  
Author(s):  
Samit Ghosh ◽  
Olufolake Adisa ◽  
Yu Yang ◽  
Fang Tan ◽  
Solomon F Ofori-Acquah

Abstract Abstract 2113 Sickle cell disease (SCD) is characterized by multiple exacerbating events that cause intravascular hemolysis. Heme released into the circulation is scavenged by multiple plasma proteins and delivered to the liver for degradation. Our recent data indicate that this process is impaired in SCD resulting in excess protein-free plasma heme (PFPH) that triggers a lethal form of acute lung injury (ALI) in mice. In this study, we tested the hypothesis that toll-like receptor 4 (TLR4) mediates heme-induced ALI. Wild-type and two TLR4 mutant strains (B6.B10ScN-Tlr4lps-del/JthJ and C3H/HeJ) were intravenously injected with a dose range of ferric heme (0–210 micromoles/kg) and respiratory function monitored using a pulse oximeter. Excess PFPH was associated with reductions in oxygen saturation (SpO2) and breath rate in the wild-type mice but not in the TLR4 variants. Lungs of heme-treated wild-type mice were congested, edematous, hemorrhagic, and had thickened alveolar walls, while no histological abnormalities were found in the TLR4 variants. All heme-treated wild-type mice succumbed within 2 hours, while all TLR4 variants survived. Transgenic mice expressing exclusively human sickle hemoglobin (SS) were intravenously injected with a small molecule TLR4 inhibitor (resatorvid/TAK-242), or a lipid vehicle prior to induction of lung injury with heme (35 micromoles/kg). TAK-242 preserved lung function in the majority of SS mice that failed to scavenge excess PFPH, while both SpO2 and breath rate deteriorated in vehicle treated mice. The unique response to heme by TAK-242 and vehicle-treated SS mice was supported by histological analysis and survival (TAK-242; 76.9% vehicle; 23.5%, n=13–17; log-rank survival test, p<0.01). We provide the first evidence that the interaction between heme and TLR4 can be pathological, specifically causing a lethal form of ALI. Our data on TAK-242, a phase II drug, offers an attractive option to explore TLR4 inhibition as a novel therapeutic strategy to limit progression of acute chest syndrome. Disclosures: Ofori-Acquah: Emory University: Patents & Royalties.


2014 ◽  
Vol 138 (5) ◽  
pp. 678-683 ◽  
Author(s):  
Salah Al-Humood ◽  
Rajaa Zueriq ◽  
Lama Al-Faris ◽  
Rajaa Marouf ◽  
Fahd Al-Mulla

Context.—Vascular occlusion in sickle cell disease causes increased levels of plasma cell-free DNA as a result of cell death and tissue damage. Objectives.—This study investigates plasma cell-free DNA concentrations in sickle cell disease patients, and aims at exploring the significance of plasma cell-free DNA as a potential biomarker in predicting its complications. Design.—Plasma cell-free DNA levels were measured using real-time quantitative polymerase chain reaction to quantitatively measure β-globin gene in blood samples from 57 sickle cell disease patients with acute vaso-occlusive crisis, 42 patients in steady state, 16 individuals with sickle cell trait, and 40 healthy controls. Results.—Plasma cell-free DNA level was significantly elevated in samples from patients with acute vaso-occlusive crisis when compared with those in steady state (P = .002), and was significantly higher both in crisis and in steady state when compared with individuals with sickle cell trait and healthy controls (P &lt; .001). There was no difference in cell-free DNA levels between individuals with sickle cell trait and healthy controls. There was no association between plasma cell-free DNA levels and various clinical complications of sickle cell disease and comorbidity. Conclusions.—Plasma cell-free DNA, as quantified by polymerase chain reaction amplification of the β-globin and human telomerase reverse transcriptase genes, is increased in sickle cell disease patients in vaso-occlusive crisis and in steady state compared with individuals with sickle cell trait and healthy controls, and may be used as a tool to diagnose and monitor the sickle cell crisis and differentiate post–packed red cell transfusion sickle cell disease patients from individuals with sickle cell trait.


Blood ◽  
2014 ◽  
Vol 123 (24) ◽  
pp. 3818-3827 ◽  
Author(s):  
Grace Chen ◽  
Dachuan Zhang ◽  
Tobias A. Fuchs ◽  
Deepa Manwani ◽  
Denisa D. Wagner ◽  
...  

Key Points NETs are present and pathogenic in sickle cell disease. Plasma heme and proinflammatory cytokines collaborate to activate release of NETs.


2003 ◽  
Vol 50 (9) ◽  
pp. 895-899 ◽  
Author(s):  
Paul G. Firth ◽  
Yoshihiko Tsuruta ◽  
Yogish Kamath ◽  
Walter H. Dzik ◽  
Christopher S. Ogilvy ◽  
...  

2006 ◽  
Vol 135 (5) ◽  
pp. 738-741 ◽  
Author(s):  
Ageliki Gerovassili ◽  
Kypros H. Nicolaides ◽  
Swee Lay Thein ◽  
David C. Rees

Author(s):  
Soi Avgeridou ◽  
Ilija Djordjevic ◽  
Anton Sabashnikov ◽  
Kaveh Eghbalzadeh ◽  
Laura Suhr ◽  
...  

AbstractExtracorporeal membrane oxygenation (ECMO) plays an important role as a life-saving tool for patients with therapy-refractory cardio-respiratory failure. Especially, for rare and infrequent indications, scientific data is scarce. The conducted paper focuses primarily on our institutional experience with a 19-year-old patient suffering an acute chest syndrome, a pathognomonic pulmonary condition presented by patients with sickle cell disease. After implementation of awake ECMO therapy, the patient was successfully weaned off support and discharged home 22 days after initiation of the extracorporeal circulation. In addition to limited data and current literature, further and larger data sets are necessary to determine the outcome after ECMO therapy for this rare indication.


Toxins ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 157
Author(s):  
Joyce Gonzales ◽  
Trinad Chakraborty ◽  
Maritza Romero ◽  
Mobarak Abu Mraheil ◽  
Abdullah Kutlar ◽  
...  

Sickle cell disease (SCD) is one of the most common autosomal recessive disorders in the world. Due to functional asplenia, a dysfunctional antibody response, antibiotic drug resistance and poor response to immunization, SCD patients have impaired immunity. A leading cause of hospitalization and death in SCD patients is the acute chest syndrome (ACS). This complication is especially manifested upon infection of SCD patients with Streptococcus pneumoniae (Spn)—a facultative anaerobic Gram-positive bacterium that causes lower respiratory tract infections. Spn has developed increased rates of antibiotics resistance and is particularly virulent in SCD patients. The primary defense against Spn is the generation of reactive oxygen species (ROS) during the oxidative burst of neutrophils and macrophages. Paradoxically, Spn itself produces high levels of the ROS hydrogen peroxide (H2O2) as a virulence strategy. Apart from H2O2, Spn also secretes another virulence factor, i.e., the pore-forming exotoxin pneumolysin (PLY), a potent mediator of lung injury in patients with pneumonia in general and particularly in those with SCD. PLY is released early on in infection either by autolysis or bacterial lysis following the treatment with antibiotics and has a broad range of biological activities. This review will discuss recent findings on the role of pneumococci in ACS pathogenesis and on strategies to counteract the devastating effects of its virulence factors on the lungs in SCD patients.


2021 ◽  
pp. 1-5
Author(s):  
Justin E. Juskewitch ◽  
Craig D. Tauscher ◽  
Sheila K. Moldenhauer ◽  
Jennifer E. Schieber ◽  
Eapen K. Jacob ◽  
...  

Introduction: Patients with sickle cell disease (SCD) have repeated episodes of red blood cell (RBC) sickling and microvascular occlusion that manifest as pain crises, acute chest syndrome, and chronic hemolysis. These clinical sequelae usually increase during pregnancy. Given the racial distribution of SCD, patients with SCD are also more likely to have rarer RBC antigen genotypes than RBC donor populations. We present the management and clinical outcome of a 21-year-old pregnant woman with SCD and an RHD*39 (RhD[S103P], G-negative) variant. Case Presentation: Ms. S is B positive with a reported history of anti-D, anti-C, and anti-E alloantibodies (anti-G testing unknown). Genetic testing revealed both an RHD*39 and homozygous partial RHCE*ceVS.02 genotype. Absorption/elution testing confirmed the presence of anti-G, anti-C, and anti-E alloantibodies but could not definitively determine the presence/absence of an anti-D alloantibody. Ms. S desired to undergo elective pregnancy termination and the need for postprocedural RhD immunoglobulin (RhIG) was posed. Given that only the G antigen site is changed in an RHD*39 genotype and the potential risk of RhIG triggering a hyperhemolytic episode in an SCD patient, RhIG was not administered. There were no procedural complications. Follow-up testing at 10 weeks showed no increase in RBC alloantibody strength. Discussion/Conclusion: Ms. S represents a rare RHD*39 and partial RHCE*ceVS.02 genotype which did not further alloimmunize in the absence of RhIG administration. Her case also highlights the importance of routine anti-G alloantibody testing in women of childbearing age with apparent anti-D and anti-C alloantibodies.


Sign in / Sign up

Export Citation Format

Share Document