scholarly journals Plasma NTPDase1 Activity Regulates Platelet Purinergic Signaling in Sickle Cell Disease

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 2026-2026
Author(s):  
Tomasz Brzoska ◽  
Elizaveta V Menchikova ◽  
Tomasz W. Kaminski ◽  
Ravi Vats ◽  
Egemen Tutuncuoglu ◽  
...  
Keyword(s):  
Sickle Cell Disease ◽  
Sickle Cell ◽  
Plasma Levels ◽  
Research Funding ◽  
Purinergic Signaling ◽  
Microvascular Endothelial Cell ◽  
Acute Chest Syndrome ◽  
Dependent Manner ◽  
Cell Disease ◽  
Pulmonary Thrombosis

Abstract Acute systemic painful vaso-occlusive episode (VOE) often serves as an antecedent to acute chest syndrome (ACS), which is a type of acute lung injury and the leading cause of mortality among sickle cell disease (SCD) patients. Based on clinical epidemiology, ACS is often preceded by thrombocytopenia and involves massive thrombosis across pulmonary artery branches in 10-20% of ACS patients. Although, released during hemolysis, adenosine diphosphate (ADP) is known to activate platelets by stimulating their P2Y1 and P2Y12 purinergic receptors, antagonists of P2Y12 have not shown any benefit in ACS therapy, justifying the need for better understanding of purinergic signaling in SCD. Ecto-nucleoside-tri-phosphate-diphosphohydrolase-1 (E-NTPDase1; CD39) maintains ADP homeostasis by degrading excessive ADP. Though CD39 inhibits ADP-dependent platelet activation and vascular thrombosis, its role in ASC is still unidentified. Here, we use intravital lung microscopy in transgenic humanized SCD mice to show that intravascular (IV) administration of ADP triggered pulmonary thrombosis in control mice but failed to trigger pulmonary thrombosis in SCD mice. Identical to intravital findings, IV ADP administration also evoked transient thrombocytopenia in control but not SCD mice, while, IV collagen led to comparable drop in platelet count in both SCD and control mice. In vitro turbidimetric aggregation study yet again demonstrated impaired SCD mouse platelet response to ADP, which was significantly augmented by CD39 inhibitor (sodium metatungstate, POM-1). Indeed, we found significantly higher plasma levels and activity of CD39 in SCD mice compared to control mice using ELISA and malachite green assays, respectively. Hemin, a major host-derived damage associated molecular pattern (DAMP) in SCD, was incubated with Human Lung MicroVascular Endothelial Cell (HMVEC-L) to assess CD39 expression using western blotting. Hemin (10 -100 µM) in a dose dependent manner decreased CD39 levels in HMVEC-L. Our current findings suggest that elevated CD39 plasma levels and activity possibly prevents ADP-mediated platelet aggregation and pulmonary thrombosis in SCD. We demonstrated that SCD milieu promotes loss of endothelial CD39, which may be directly associated with increased CD39 plasma levels and activity. Current study explains why P2Y12 blockers are not effective in SCD therapy and warrant the need for further studies to understand the role of purinergic signaling in pathogenesis of ACS. Disclosures Sundd: Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding; CSL Behring Inc: Research Funding; Bayer: Research Funding.

scholarly journals CD39 As a Master Regulator of Pulmonary Thrombosis in Sickle Cell Disease

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 2266-2266
Author(s):  
Tomasz Brzoska ◽  
Egemen Tutuncuoglu ◽  
Stevan P. Tofovic ◽  
Edwin K. Jackson ◽  
Mark T Gladwin ◽  
...  
Keyword(s):  
Sickle Cell Disease ◽  
Sickle Cell ◽  
Clinical Evidence ◽  
Purinergic Signaling ◽  
Adenosine Diphosphate ◽  
Acute Chest Syndrome ◽  
Cell Disease ◽  
Pulmonary Thrombosis ◽  
Genetic Mechanisms ◽  
And Control

Acute systemic painful vaso-occlusive crisis (VOC) often serves as an antecedent to acute chest syndrome (ACS), which is a type of acute lung injury and the leading cause of mortality among sickle cell disease (SCD) patients. Thrombocytopenia secondary to pulmonary thrombosis is major risk factor for ACS, however, only 20% of ACS patients are diagnosed with pulmonary thrombosis as an underlying cause of ACS. Although clinical evidence supports the presence of prothrombotic state in subset of SCD patients, the molecular, cellular and genetic mechanisms that selectively render subset of SCD patients at either higher or lower risk of developing pulmonary thrombosis remains elusive. Adenosine diphosphate (ADP) released from lysed erythrocytes can activate platelets by stimulating their purinergic P2Y1 and P2Y12 receptors, however, P2Y12 receptor antagonists have not shown any benefit in clinical trials, justifying the need for better understanding of purinergic signaling in SCD. Here, we use intravital lung microscopy in transgenic humanized SCD mice to show that intravenous administration of ADP triggered pulmonary thrombosis in control mice but failed to trigger pulmonary thrombosis in SCD mice. In contrast, collagen evoked pulmonary thrombosis identically in both control and SCD mice. Identical to intravital findings, IV ADP administration also evoked transient thrombocytopenia in control but not SCD mice, while, IV collagen led to comparable drop in platelet count in both SCD and control mice. ADP is metabolized by the ecto-nucleoside-tri-phosphate-diphosphohydrolase-1 (E-NTPDase1) CD39. IV administration of fluorescent analogue of ADP, N⁶- ethenoadenosine- 5'- O- diphosphate (ε-ADP) followed by invivo microdialysis and HPLC analysis revealed impaired ε-ADP degradation in SCD mice, suggestive of decreased CD39 activity. Our current findings suggest that loss of CD39 activity in SCD possibly prevents ADP-mediated pulmonary thrombosis. Currently, experiments are underway to identify pathways contributing to loss of CD39 activity in SCD, how that affects purinergic signaling and whether selective activation vs deactivation of this pathway is responsible for risk of pulmonary thrombosis in only 20% of ACS patients. 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.

scholarly journals Regulatory Genetic Variation at the S100B Gene Associates with Vaso-Occlusive Manifestations in Sickle Cell Disease

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 1063-1063 ◽  
Author(s):  
Xu Zhang ◽  
Wei Zhang ◽  
Santosh L. Saraf ◽  
Sergei Nekhai ◽  
Mark T Gladwin ◽  
...  
Keyword(s):  
Linkage Disequilibrium ◽  
Sickle Cell Disease ◽  
Sickle Cell ◽  
Sickle Cell Anemia ◽  
Research Funding ◽  
Genetic Regulation ◽  
Acute Chest Syndrome ◽  
Cell Disease ◽  
Thrombotic Risk ◽  
Increased Risk

Abstract In sickle cell disease (SCD) polymerization of hemoglobin S under deoxygenated conditions causes vaso-occlusion, which can manifest as acute pain crisis and progressive bone/organ damage. Molecular studies have attributed vaso-occlusion to elevated vascular adhesion and inflammatory responses, whereas the genetic regulation has only recently been assessed. Genomic DNA isolated from peripheral blood mononuclear cells (PBMCs) was hybridized to Illumina Human 610-Quad SNP array for the PUSH and Walk-PHaSST cohorts and to Affrymetrix SNP 6.0 array for the Howard SCD expression cohort. Single nucleotide polymorphisms (SNPs) for 381 PUSH, 525 Walk-PHaSST, and 55 Howard patients were imputed to 1000 genomes project phase 3 data. Messenger RNA from PBMCs was profiled using Affymetrix Human Exon 1.0 ST Array for the Howard expression cohort and Affymetrix Human gene 2.0 ST array for the UIC expression cohort. Patients within the PUSH and Walk-PHaSST cohorts were classified to four groups according to a cumulative pain score, calculated based on pain frequency and questionnaire description of pain intensity. Pain grouping was examined for correlation with other SCD complications using Cochran Armitage test. History of acute chest syndrome (ACS, PUSH P=3.8×10-9, Walk-PHaSST P=2.4×10-5) and avascular necrosis (AVN, PUSH P=4.1×10-4, Walk-PHaSST P=3.7×10-5) were the most significant clinical manifestations that consistently associated with pain in the two cohorts. To investigate the genetic control of vaso-occlusive manifestations with appropriate power, we leveraged genetic association of pain, ACS, and AVN with genetic regulation of disease-specific gene expression. We mapped expression quantitative trait loci (eQTL) in the Howard expression cohort for SNPs<1 Mb away from gene ends per expression trait. At a permutation based false discovery rate of 5%, 1004 independent eQTL (linkage disequilibrium r2 ≤0.3 per trait) were identified for 880 genes. Focusing on 129 genes whose expression was altered in PBMCs in sickle cell anemia by at least 1.5-fold [1], we identified six eQTL for five differential genes (up-regulated: OSBP2, SLC14A1, RNF182, CCRL2; down-regulated: S100B). The six eQTL were assessed for association with pain, ACS, and AVN, using the Walk-PHaSST cohort for discovery and the PUSH cohort for validation. At a significance of Bonferroni corrected P=0.05 (nominal P=0.0083), an eQTL of S100B (rs2154586) significantly associated with AVN in the Walk-PHaSST cohort (OR=1.8, P=0.00061) and the association was replicated in the PUSH cohort (OR=2.7, P=0.0052). The A allele of the eQTL (frequency=0.18) associated with increased risk for AVN and increased expression level of S100B in the Howard expression cohort (β=0.40, P=1.6 ×10-6). In an additional 64 sickle cell anemia patients without hydroxyurea treatment from the UIC expression cohort, expression levels of S100B were significantly elevated in the individuals with AVN (β=0.28, P=0.029). The 24 SNPs in linkage disequilibrium with the eQTL (r2 >0.7) constituted the third most significant peak in a meta-analysis of genome-wide association of AVN in the PUSH and Walk-PHaSST cohorts. To test the hypothesis that genes involved in vaso-occlusion in SCD may affect thrombotic risk in non SCD individuals, we examined the association of the locus with venous thromboembolism (VTE) in the ARIC, JHS and CHS cohorts from dbGaP. The locus was imputed in African Americans and VTE was defined as being told by a doctor to have a blood clot in the leg or lung as answered in questionnaires during medical exams. The SNPs were associated with VTE using logistic linear regression adjusting for age, gender, enrollment site, and the first 15 principal components per cohort. The risk allele of the leading SNP for AVN consistently associated with increased risk of VTE across the cohorts, with a combined P=0.0041 and OR=1.4. S100B encodes a calcium sensor that appears to intervene in a variety of biological functions. S100B can mediate the inflammatory effects of damage-associated molecular pattern molecules (DAMPs) produced by erythrocyte hemolysis [2, 3]. Serum concentration of S100B correlates with LDH and with TCD-determined peak velocity of the left middle cerebral artery in thalassemia patients[4]. Polymorphisms of S100B that lead to increased serum levels are associated with increased risk of ischemic stroke in the Chinese population[5]. Disclosures Nekhai: NIMHD, NIH: Research Funding; NHLBI, NIH: Research Funding; NIAID, NIH: Research Funding.

Clinical Outcomes For Patients With Sickle Cell Disease: 24-Month Follow-Up In An Ongoing 3-Year, Prospective, Non-Interventional Registry Trial

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 988-988
Author(s):  
Matthew M Heeney ◽  
Brigitta U. Mueller ◽  
Brad Baltz ◽  
Patricia Adams-Graves ◽  
Elizabeth Yang ◽  
...  
Keyword(s):  
Sickle Cell Disease ◽  
Clinical Outcomes ◽  
Sickle Cell ◽  
Research Funding ◽  
Research Laboratory ◽  
Laboratory Research ◽  
Similar Proportion ◽  
Acute Chest Syndrome ◽  
Cell Disease

Abstract Introduction Patients (pts) with sickle cell disease (SCD) experience a heterogeneous clinical course, with a range of symptoms and sequelae. We describe clinical outcomes and treatment patterns from a prospective registry of pediatric and adult pts with SCD. Methods Pts ≥2 years old with HbSS, HbSC, or HbS/β-thalassemia were enrolled from 57 US centers and assessed every 6 months (mos) for up to 3 years. Differences between pediatric and adult pts at 24 mos follow-up are reported. (ClinicalTrials.gov NCT01220115). Results A total of 498 pts completed the baseline visit (74.1% HbSS disease, 15.3% HbSC, and 10.4% HbS/β-thalassemia) (Table 1 ). At baseline, the following conditions were more frequent in adults: avascular necrosis, gallbladder disease, leg ulcers, and pulmonary hypertension. Pediatric pts had more frequent asthma/reactive airway disease, dactylitis, and splenic sequestration. The nature of sickle-related events varied between adult and pediatric pts (Table 2 ). Prior to study, adults had higher frequencies of pain crises, strokes, and priapism, while pediatric pts had more frequent infections and acute chest syndrome (ACS)/pneumonia. On study, a similar proportion of pediatric and adult pts (56.4% overall) were hospitalized, most frequently due to pain, fever, and ACS/pneumonia; a greater proportion of pediatric pts were hospitalized due to fever (P<0.05). The percentage of pts who received a transfusion and/or chelation while on study was similar between adult and pediatric pts. Almost half of the pediatric and adult groups received hydroxyurea prior to and during the study. High rates of absenteeism were observed, with 51% of pediatric pts and 44.4% of adults missing 1 to 10 days of school or work in the year before study. Conclusions Despite advances in care, SCD is associated with significant morbidity that contributes to high rates of hospitalization and absenteeism in both pediatric and adult pts. Continued follow-up in this registry will provide additional information about disease patterns and pt management. Disclosures: Heeney: Novartis: Consultancy, Research Funding; Eli Lilly: Research Funding. Off Label Use: Hydroxurea is indicated to reduce the frequency of painful crises and to reduce the need for blood transfusions in adult patients with sickle cell anemia. It is not approved for use in children. Mueller:Novartis: Research Funding. Adams-Graves:Novartis: Consultancy, Speakers Bureau. Paley:Novartis: Employment. Esposito:Novartis: Employment. Katie:Novartis: Employment. Vichinsky:Novartis: Consultancy, Research Funding; ApoPharma: Consultancy, Research Funding; ARUP: Research Funding, Research Laboratory, Research Laboratory Other.

scholarly journals Drepadom - Home Care Services and Hospitalizations for Sickle Cell Disease Patients during the Covid-19 Pandemic

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 12-12
Author(s):  
Gonzalo De Luna ◽  
Nicolas Lemonier ◽  
Alexis Aidan ◽  
Lea Bontemps ◽  
Manuel Hautefaye ◽  
...  
Keyword(s):  
Sickle Cell Disease ◽  
Sickle Cell ◽  
Research Funding ◽  
Chronically Ill ◽  
Full Recovery ◽  
Acute Chest Syndrome ◽  
Cell Disease ◽  
Medical Decisions ◽  
Daily Monitoring

INTRODUCTION Besides many problematics the Covid-19 pandemic has triggered, one issue remains the care of chronically ill patients. Regarding sickle cell disease (SCD), patients often present co-morbidities that could predispose them to poor outcome if they get infected. Vaso-occlusive crisis (VOC), a characteristic manifestation of SCD, is the first cause of patients 'hospitalizations. Here, we describe how our sickle cell referral center has managed outpatient care, with the constant preoccupation of minimizing risks for our patients and avoid them unnecessary trips to heavily burdened hospital settings. DESCRIPTION OF SETTING With the outbreak of Covid-19, our primary obsession was to provide continuous care for our patients, while ensuring their safety. All appointments were canceled when possible and patients were instructed to comply with the national lock down procedures. A hotline and helpdesk were setup as the first stage of our structure. When patients described symptoms of VOC and/or light breathing difficulties, they were enlisted for daily monitoring. This stage two consisted of calling patients daily with a specific set of questions, regarding management and improvement or deterioration of their symptoms. A dedicated team of dentists, who all volunteered and received specific training, managed both stage 1 and 2, along with nurses. SCD specialists supervised these two stages for medical decisions. All symptoms were recorded and reported. If symptoms disappeared, the patient's name was discarded from the list. If there was a worsening or no improvement of the patient's condition, he was moved to stage three by the SCD expert, with the deployment of homecare service. A whole network was then setup, with the delivery of oxygen supply at the patient's house, dispatch of a medical prescription to a neighboring pharmacy and daily visits from homecare service providers. Both opioids and parenteral treatments were prescribed and monitoring was performed daily (blood pressure, temperature, respiratory rate, pain, etc...). On the first visit, a blood sample was sent to a laboratory, to allow calculation of the PRESEV score (Bartolucci et al., 2016). This score, established by team members and colleagues, assesses the risk of acute chest syndrome (ACS). Moreover, it has just been validated by a multicenter international study (PRESEV II - under writing process). In case the PRESEV score was ≤ 5, home hospitalization was pursued. In case this score was ≥11, the patient was sent to hospital for constant monitoring and full comprehensive care. For low and intermediate scores, the patient was referred to hospital for any aggravation. The helpdesk was in constant interaction with nurses and providers of homecare services and status and evolution of the patient's global condition was reported daily for medical decisions. In addition, patients with home hospitalization care were called daily by the helpdesk, to ensure proper care and satisfaction. When home hospitalization was over, the patient automatically came back to stage two for a daily follow-up until full recovery. Early discharged patients could either re-integrate stage 2 or 3 for daily monitoring until full recovery. Out of the 305 patients included in this system, with a total of 2068 calls between March 23rd and May 29th. Seventy five were included for home hospitalization. Mean age was 36 years old [±9], sex ratio was 45/30 (female/male), mean homecare follow up was 6 days (±3), 16 patients also had Covid-19. Thirteen patients (17.3%) were hospitalized: one for an acute chest syndrome, two for a Covid-19 infection and nine for VOC management. Only one patient was in ICU due to a salmonella septicemia. No death was reported. PERSPECTIVES The Covid-19 pandemic has highlighted the need for profound reshaping of healthcare systems worldwide. In this particular context, the structure we have installed, DREPADOM, allowed follow up and monitoring of two profiles of patients: at-risk population of SCD patients and Covid-19 positive SCD patients. With the ongoing situation, our delocalized hospitalization system has proven interesting enough to enter a new phase: DREPADOM was selected as part of a public call for tenders, for financial support to make the structure permanent (DREPADOM - APRES). Disclosures Habibi: Pfizer: Consultancy; Bluebird: Consultancy; Addmedica: Consultancy; Novartis: Consultancy. Bartolucci:GBT: Consultancy; Roche: Consultancy; Emmaus: Consultancy; Innovhem: Other; Addmedica: Research Funding; HEMANEXT: Consultancy; Novartis: Consultancy; ADDMEDICA: Consultancy; Fabre Foundation: Research Funding; Novartis: Research Funding; Bluebird: Consultancy; AGIOS: Consultancy; Bluebird: Research Funding.

scholarly journals Risk Factors for Adverse Maternal and Fetal Outcomes in Pregnant Patients with Sickle Cell Disease

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 3117-3117
Author(s):  
Sherraine Della-Moretta ◽  
William Marshall ◽  
Rui Li ◽  
Erin Cleary ◽  
Philip Samuels ◽  
...  
Keyword(s):  
Risk Factors ◽  
Sickle Cell Disease ◽  
Sickle Cell ◽  
Research Funding ◽  
Maternal Age ◽  
Acute Chest Syndrome ◽  
Hypertensive Disorders Of Pregnancy ◽  
Cell Disease ◽  
History Of ◽  
Maternal Bmi

Abstract Background Approximately 100,000 Americans are affected by sickle cell disease (SCD), an inherited hematologic disorder. In women with sickle cell disease, pregnancy is associated with increased maternal and fetal adverse outcomes (Elenga et al). However, there is a paucity of data on risk factors for adverse events in this population. This retrospective study seeks to add to the deficient repertoire of information regarding maternal and fetal outcomes in patients with sickle cell disease and their children. Methods We retrospectively evaluated pregnancy outcomes of women with SCD who had previously undergone echocardiography from the year 2000-2021. The associations between clinical variables and adverse hematologic (AHE), cardiac (ACE), obstetric (AOE) and fetal/neonatal (ANE) events were evaluated by the Generalized Linear Model (GLM). The adverse hematologic events were vaso-occlusive crisis (VOC) antepartum and postpartum, acute chest syndrome, venous thromboembolism antepartum and postpartum, and transfusion antepartum. Results We identified 43 women/59 pregnancies with a median maternal age 27 years old (interquartile range [IQR] 20), pre-pregnancy BMI 25 kg/m2 (IQR 16). Maternal sickle cell genotype was SS in 31 (72%) women/37 (63%) pregnancies, SC in 8 (18%) women/18 (31%) pregnancies, and other genotype in 4 (9%) women/4 (7%) pregnancies. Prior venous thromboembolism was present in 12 (27%) women/15 (25%) pregnancies and prior acute chest syndrome (ACS) in 33 (80%) women/41 (75%) pregnancies. In the year before pregnancy, 24 (56%) women were admitted at least once for VOC. There were no maternal deaths during pregnancy or up to 1 year postpartum. AHE (n = 171) occurred in 43 (73%) pregnancies (Figure A), with a median of 2 (range 0-13) AHE per pregnancy. AHE were more common with genotype SS, history of ACS, history of ³ 10 lifetime transfusions, admission for VOC in the year before pregnancy, tricuspid regurgitation velocity (TRV) &gt;2.5 m/s on echocardiogram, and increased maternal age, and less common with increased hemoglobin (Figure B). ACE were rare (n = 3) (Figure A) and weakly associated with increased maternal age (Figure C). AOE (n = 37) occurred in 27 (45%) pregnancies (Figure A) and were associated with lower pre-pregnancy maternal BMI (Figure D). ANE (n = 54) occurred in 27 (46%) of pregnancies, and were associated with maternal hypertensive disorders of pregnancy (Figure E). Conclusions We found that AHE during pregnancy in women with SCD were associated with genotype SS, history of ACS, ³ 10 lifetime transfusions, admission for VOC in the year before pregnancy, higher maternal age, and inversely related to hemoglobin. In addition, AHE during pregnancy were associated with TRV &gt;2.5 m/s on echocardiogram, which has not been previously shown in women with SCD. These data may be useful to identify women at increased risk during pregnancy. Data show that patients with sickle cell disease who have more disease-related complications including history of acute chest syndrome, frequent pain crisis, elevated TRV on echocardiogram, and lower hemoglobin are at greater risk for AHE. This suggests that disease severity is directly related to outcomes. The association between increased maternal age and ACE has been demonstrated in the past in women without SCD (DeViti et al). The same can be noted for the association of AOE with lower maternal BMI (Verma et al), and ANE being associated with maternal hypertensive disorders of pregnancy (Lugobe et al). In the future, prevention of these complications will be key. Future directions include determining the effect of disease-modifying therapy on these outcomes, though safety during pregnancy has not yet been demonstrated for more novel agents such as voxelotor and crizanlizumab. With more information on these risk factors, we hope that modification and treatment can result in better outcomes. Figure 1 Figure 1. Disclosures Desai: Pfizer: Other: Publication Fee, Research Funding; Foundation for Sickle Cell Research: Honoraria; Forma: Consultancy; Novartis: Research Funding, Speakers Bureau; Global Blood Therapeutics: Honoraria, Research Funding.

scholarly journals A Pilot Study of Eptifibatide for Treatment of Acute Pain Episodes in Sickle Cell Disease.

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 2102-2102
Author(s):  
Payal C Desai ◽  
Julia Brittain ◽  
Susan Jones ◽  
Adam McDonald ◽  
Douglas R Wilson ◽  
...  
Keyword(s):  
Sickle Cell Disease ◽  
Board Of Directors ◽  
Sickle Cell ◽  
Acute Pain ◽  
Research Funding ◽  
Point Estimate ◽  
Acute Chest Syndrome ◽  
Cell Disease ◽  
Opioid Use ◽  
Advisory Committees

Abstract Abstract 2102 Background: Despite the abundant laboratory evidence of platelet activation and inflammation in sickle cell disease (SCD), the contribution of these changes to the pathogenesis of SCD remains uncertain. Patients with SCD exhibit increased platelet activation in the non-crisis, “steady state,” and further increases with acute pain episodes. In addition, levels of the inflammatory mediator, CD40 ligand (CD40L) are increased in the plasma and significantly reduced in the platelets of SCD patients compared to healthy individuals. CD40L may contribute to the pathogenesis of acute pain episodes. Despite an improved understanding of the pathophysiology of SCD, the treatment of acute pain episodes is supportive. We performed a randomized, placebo-controlled study to evaluate the safety and efficacy of eptifibatide, a synthetic peptide inhibitor of the glycoprotein (GP) IIb/IIIa receptor, in patients with SCD during acute painful episodes. Methods: In this single site placebo-controlled trial, eligible patients admitted for acute painful episodes received eptifibatide (two 180 mg/kg boluses 10 minutes apart, followed by a continuous infusion at 2 mg/kg/min for 6 hours) or placebo at a ratio of 2:1. The Post-Treatment Phase lasted for up to 7 days or until resolution of the crisis, whichever was shorter, but no less than 24 hours after discontinuation of infusion. The Follow-up Phase included safety evaluations obtained 14 to 17 days and 28 to 35 days after discontinuation of infusion. The primary outcomes were major bleeding episodes and the largest observed decrease in platelet count during the study. We also evaluated the effect of eptifibatide on the duration of acute pain episodes, pain intensity, duration of hospitalization, total opioid use and acute chest syndrome. Results: Thirteen patients (SS - 10, Sb0 - 2, SC - 1) were randomized to receive either eptifibatide (N=9; 6 females; median age - 25 years) or placebo (N=4; 3 females; median age - 31 years). One patient in the eptifibatide arm withdrew consent following completion of study drug infusion and 1 patient in the placebo arm was withdrawn early because she did not meet eligibility criteria. In the intent-to-treat analysis, there were no major bleeding episodes in either group (point estimate of difference in eptifibatide vs. placebo proportion: 0.0, 95% CI; −0.60, 0.37).There was one minor bleeding episode in a patient on the eptifibatide arm (point estimate of difference in eptifibatide vs. placebo proportion: 0.11, 95% CI: −0.502, 0.494). There was a trend for the largest decrease in platelet count to be greater in the eptifibatide arm compared to the placebo arm, although the difference was not statistically significant (Hodges-Lehman estimate of location shift for eptifibatide vs. placebo: −82, 95% CI; −281, 54). There was no significant difference in the proportion of patients with thrombocytopenia between the treatment groups (point estimate of difference in eptifibatide vs. placebo proportion: 0.11, 95% CI: −0.587, 0.495). The median time to discharge and the median time to crisis resolution were 3.0 days for both treatment arms. The median total opioid use was 400.2 morphine equivalents (ME) for the eptifibatide group and 1471 ME for the placebo group (Hodges-Lehman estimate of location shift for eptifibatide vs. placebo: −65.8, 95% CI: −2519, 1700). There was one episode of acute chest syndrome in each treatment arm. Conclusions: In this small study of SCD patients hospitalized with acute painful episodes, eptifibatide appeared to be safe, but did not improve the times to crisis resolution or hospital discharge. Eptifibatide was associated with a reduced requirement for opioid analgesics, although the difference was not statistically significant. Clinicaltrials.gov Identifier: NCT00834899. Disclosures: Parise: BD: Consultancy; Biogen-Idec: Consultancy; NIH: Research Funding; AHA: Research Funding; SCDAC-NIH: Membership on an entity's Board of Directors or advisory committees; BRI Milwaukee: Membership on an entity's Board of Directors or advisory committees. Ataga:Pfizer: Consultancy; HemaQuest Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Adventrx Pharmaceuticals: Consultancy. Off Label Use: Eptifibatide, a glycoprotein IIb/IIIa inhibitor, was evaluated as treatment for acute pain episodes in patients with sickle cell disease.

scholarly journals Thrombin-Mediated Activation of PAR-1 Contributes to Microvascular Stasis in Mouse Models of Sickle Cell Disease Via Increased Endothelial Expression of P-Selectin and VWF

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 266-266
Author(s):  
Erica Sparkenbaugh ◽  
Chunsheng Chen ◽  
Julia Nguyen ◽  
Shaobin Wang ◽  
Gregory M. Vercellotti ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Sickle Cell Disease ◽  
Mouse Model ◽  
Mouse Models ◽  
Sickle Cell ◽  
Research Funding ◽  
Bleeding Complications ◽  
Cell Physiology ◽  
Dependent Manner ◽  
Cell Disease

Abstract Sickle cell disease (SCD) is caused by a single nucleotide mutation in the β-globin gene, resulting in an altered red cell physiology that causes vascular complications such as hemolytic anemia, chronic inflammation, activation of coagulation, and vaso-occlusion. We have shown that infusion of hemin results in tissue factor (TF)-dependent activation of coagulation in mice. Furthermore, TF-dependent activation of coagulation contributes to inflammation in a mouse model of SCD. Interestingly, thrombin-dependent inflammation in sickle cell mice was not attenuated by deficiency of the main thrombin receptor protease activated receptor-1 (PAR-1). However, others have shown that the activation of endothelial cell PAR-1 with agonist peptide enhances interactions of these cells with sickle RBCs in a P-selectin-dependent manner. Importantly, P-selectin inhibition reduces microvascular stasis in mouse models of SCD and prevents vaso-occlusive crisis in sickle cell patients. We propose that thrombin-mediated PAR-1 activation promotes microvascular stasis in mouse models of SCD via increased expression of P-selectin and VWF on the endothelium, triggered by exocytosis of Weibel-Palade bodies. To investigate if the TF/thrombin/PAR-1 pathway contributes to microvascular stasis, dorsal skinfold chambers were implanted in NY1DD sickle mice 3 days before the experiment. Microvascular stasis was determined in 20-25 preselected micro-vessels in response to intravenous infusion of stroma-free hemoglobin (SFH, 1.6 µmol/kg) and was expressed as % non-flowing vessels (mean ± SEM). We previously demonstrated that infusion of SFH results in microvascular stasis that is inhibited by hemopexin in NY1DD mice, indicating that hemoglobin releases heme into the circulation. In NY1DD mice treated with control IgG antibody, SFH infusion caused stasis in 28.3 ± 1.7% and 36.7 ± 1.7% of preselected vessels at 1 and 4 hrs after infusion, respectively. Treatment with an inhibitory anti-TF antibody 1H1 (25 mg/kg; IP) 30 minutes before SFH infusion significantly reduced stasis to only 3.3 ± 1.5% and 2.8 ± 1.6% of vessels at 1 and 4 hrs, respectively (p<0.01). To investigate if TF contributes to SFH-induced microvascular stasis via generation of downstream coagulation proteases, NY1DD mice were fed with control chow or chow containing either Factor Xa (FXa) inhibitor rivaroxaban (0.4 mg/g chow) or thrombin inhibitor dabigatran (10 mg/g chow) ad libitum for 4 days prior to stasis experiments. We previously showed that these doses efficiently anticoagulated sickle mice without bleeding complications. FXa inhibition significantly reduced stasis at 1 hr (4.9 ± 0.1% versus 22.4 ± 3.8%, p<0.001) and 4 hrs (1.7 ± 1.6% versus 12.8 ± 1.9%, p<0.001) after SFH injection. Similarly, dabigatran also significantly attenuated SFH-induced stasis (3.1 ± 1.5% non-flowing vessels at 1 hour and 1.6 ± 1.6% non-flowing vessels at 4 hours). Next, to investigate if thrombin contributes to SFH-induced stasis through activation of PAR-1, we used bone marrow transplantation to generate sickle mice lacking PAR-1 expression in all non-hematopoietic cells. PAR-1+/+ and PAR-1-/- mice were lethally irradiated and transplanted with bone marrow from Townes sickle (SS) mice. Efficient reconstitution of bone marrow was confirmed by hemoglobin electrophoresis. We found that PAR-1-/- SS mice were significantly protected from SFH-induced stasis compared to PAR-1+/+ SS mice at both 1 hr (13.2 ± 3.4% versus 37.6 ± 3.9% stasis; P<0.001) and 4 hrs (6.6 ± 1.7% versus 18.0 ± 1.5% stasis; p<0.05) after hemoglobin challenge. We have previously shown that a monoclonal antibody to murine P-selectin or a polyclonal antibody to VWF markedly inhibit stasis in sickle mice. After the 4 hr stasis measurement, lungs were harvested from PAR-1+/+ SS and PAR-1-/- SS the mice and stained for P-selectin, VWF, and CD31 (a marker for endothelial cells). We found that intensity of P-selectin and VWF staining was markedly reduced in the lungs of PAR-1-/- SS mice compared to the staining observed in lungs of PAR-1+/+ SS mice. Our data indicates that SFH-induced microvascular stasis is significantly diminished by inhibition of TF, FXa, or thrombin activity or knockout of endothelial PAR-1, which leads to reduced expression of P-selectin and VWF on endothelium in a mouse model of SCD. We speculate that inhibiting the TF/thrombin/PAR-1 axis may reduce vaso-occlusive crises in SCD patients. Disclosures Vercellotti: CSL Behring: Research Funding. Belcher:CSL Behring: Research Funding.

scholarly journals Incentive Spirometry to Prevent Acute Chest Syndrome in Adults with Sickle Cell Disease

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 3660-3660
Author(s):  
Bart J. Biemond ◽  
Charlotte F.J. Van Tuijn ◽  
Aafke E. Gaartman ◽  
Erfan Nur ◽  
A. W. Rijneveld
Keyword(s):  
Sickle Cell Disease ◽  
Sickle Cell ◽  
Risk Score ◽  
Predictive Value ◽  
Plasma Levels ◽  
Adult Patients ◽  
Acute Chest Syndrome ◽  
Control Group ◽  
Cell Disease ◽  
Incentive Spirometry

Abstract Introduction: Amongst patients with sickle cell disease (SCD) the leading cause of death is the acute chest syndrome (ACS). This pneumonia-like complication frequently occurs during or shortly after a vaso-occlusive crisis (VOC). In pediatric patients hospitalized for VOC, incentive spirometry has demonstrated to prevent the development of ACS. This study was designed to determine if a comparable effect of incentive spirometry can be demonstrated in adult patients with SCD. Furthermore, we aimed to validate the ability of the Bartolucci score to identify patients at risk of ACS and assessed the value of procalcitonin as a potential biomarker for ACS . In addition, clinical characteristics and laboratory results were determined to identify potential risk factors. Methods: In this multicenter prospective randomized trial, we included consecutive adult patients (≥18 yr) admitted for VOC presenting with chest or back pain above the diaphragm. Patients were randomly assigned to spirometry or control group. Patients presenting with ACS were excluded. A chest radiograph was performed 5 days after admission, or sooner when clinically indicated, in order to diagnose pulmonary abnormalities. ACS was defined as a new infiltrate/atelectasis combined with pulmonary symptoms. At presentation, procalcitonin plasma levels were assessed and the Bartolucci risk score was calculated to determine to the risk of developing ACS for each patient. In addition, clinical and laboratory parameters were compared between patients with and without ACS during admission. Results: In total 66 episodes of hospitalization for VOC in 48 patients were included. Median age was 26 years and 46 of the hospitalizations concerned patients with a severe genotype (HbSS/HbSβ0 thalassemia) versus 20 hospitalization with a mild genotype (HbSC/HbSβ+thalassemia). The overall incidence of ACS in this study cohort was 19.7%. In the spirometry group, ACS was diagnosed in 5/34 (14.7%) hospitalizations compared to 8/32 (25%) hospitalizations in the control group (OR 0.5 [0.15-1.8]; P=.293). Twelve of the 13 ACS episodes occurred in patients with a severe genotype. The Bartolucci risk score could be calculated for 50 hospitalizations. The scores area under the curve (AUC) was 0.747 (P=.013), with a negative predictive value (NPV) of 94% and a positive predictive value (PPV) of 31%. No difference in procalcitonin plasma levels were found between patients with and patients without ACS (0.52 ± 1.56 μg/ml versus 0.56 ± 1.44 μg/ml, respectively). At baseline, hemoglobin levels were significantly lower while LDH plasma levels, leukocyte and platelet counts were significantly higher in ACS hospitalizations as compared to non-ACS hospitalizations. Patients who developed ACS showed significantly more documented fever during admission (61.5% vs 17.0%) and a longer length of hospital stay (median 10.0 days vs 4.5 days). Conclusion: Incentive spirometry did not significantly reduce the development of ACS in this prospective study in adult patients with SCD admitted with VOC and pain above the diaphragm. Procalcitonin plasma levels and the Bartolucci score could not accurately identify patients that at risk to develop ACS, but a low score appeared to be a reliable tool to identify patients with a low risk of ACS. Disclosures No relevant conflicts of interest to declare.

scholarly journals Soluble P-Selectin Levels in Patients with Sickle Cell Disease Reflect Platelets' Activation Rather Than Endothelial Dysfunction

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 4829-4829
Author(s):  
Ersi Voskaridou ◽  
Mantzou Aimilia ◽  
Pagona Flevari ◽  
Maria Dimopoulou ◽  
Veroniki Komninaka ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Endothelial Dysfunction ◽  
Sickle Cell Disease ◽  
Clinical Features ◽  
Sickle Cell ◽  
Research Funding ◽  
Iron Accumulation ◽  
Acute Chest Syndrome ◽  
Cell Disease ◽  
Soluble P

Background: Vascular occlusion is a major cause of the morbidity associated with sickle-cell disease (SCD). The tendency of sickle red blood cells to adhere to the vascular endothelium is believed to be a major contributor and possibly primary cause of the vaso-occlusive process. Therefore mediators of adhesion have become a potential new target for pharmacological therapy to combat the complications of SCD. One of the molecules involved in this process is P-Selectin or CD62P, a cell adherence molecule that is rapidly and chronically expressed on the surface of endothelial cells and platelets when activated. P-Selectin is found in the plasma of normal individuals at ng/mL concentrations. Circulating soluble P-Selectin (sP-Selectin) appears to be slightly smaller than native P-Selectin. An alternatively spliced mRNA encoding a form of human P-Selectin lacking the transmembrane anchoring domain has been reported for both megakaryocytes and endothelial cells, and evidence suggests that the majority of circulating sP-Selectin arises in this manner. We and others have reported elevated sP-Selectin levels in SCD even in steady phase. Recently, a humanized monoclonal antibody that binds to P-Selectin and blocks its interaction with P-selectin glycoprotein ligand 1 (PSGL-1) has been administered to patients with SCD, resulting in an amelioration of painful VOC. In this context we aimed to explore if sP-Selectin levels could be used to choose among the SCD patients those who might benefit from the new therapy. Patients and Methods: Eighty adult Caucasian patients with HbS/βthal at steady phase [40 patients under hydroxyurea (HU+) treatment and 40 patients without hydroxyurea (HU-) treatment] were included in this study, while 20 apparently healthy individuals of similar age and gender served as controls. Along with sP-Selectin levels, measured with the same method as reported previously (Human sP-Selectin/CD62P Immunoassay, R&D Systems, Minneapolis, MN, USA), other parameters of hemolysis, inflammation, endothelial dysfunction, iron accumulation and clinical features of the disease were evaluated. Results are expressed as median values ± SEM. Results: We found that sP-Selectin levels were elevated in 45/80 (56%) patients with HbS/βthal compared to controls (108.2±6.3 vs. 69.3±4.1ng/mL, respectively, p<0.001), independently of patients' βthal genotype and correlated strongly with PLT count (r=0.760, p<0.001). Regarding HU treatment, sP-Selectin levels did not differ between (HU+) and (HU-) patients (112.5±9.8 vs. 100.3±7.4ng/mL, respectively, p>0.07). No significance correlation was found between sP-Selectin levels and markers of: hemolysis (RPI: r=0.191, p>0.100); LDH: r=0.103, p>0.360 and bilirubin: r=0.171, p>0.130); inflammation (hs-CRP: r= 0.002, p>0.842); endothelial dysfunction (vWF:antigen: r=0.141, p>0.210 and ADAMTS-13: r=0.089, p>0.507). Regarding iron accumulation no correlation was found between sP-Selectin and ferritin levels (r=0.090, p>0.438), while a weak negative correlation was found with hepcidin-25 levels (r=-0.283, p=0.018). Furthermore, no correlation was found between sP-Selectin levels and history of clinical complications such as VOC (p>0.795), acute chest syndrome, venous and arterial thrombosis and mean pulmonary artery pressure values, (p>0.402). Conclusion: In this study, we proceeded with an external validation procedure of sP-Selectin determination in patients with HbS/βthal (keeping the same methodology in a different cohort of patients), and we found elevated levels of sP-Selectin with the evidence of PLTs' secretion origin, as no correlation found with other markers of endothelial dysfunction and inflammation. Interestingly, we failed to find a significant link of sP-Selectin levels with other markers of disease severity and/or clinical features of SCD. Thus, we consider that the use sP-Selectin as a biomarker of assessment and treatment of endothelial dysfunction in patients with SCD is of almost negligible importance. Disclosures Voskaridou: Genesis: Consultancy, Research Funding; Protagonist: Research Funding; Celgene Corporation: Consultancy, Research Funding; Acceleron: Consultancy, Research Funding; Addmedica: Membership on an entity's Board of Directors or advisory committees.

scholarly journals Hydroxyurea Prescription Fills and Adherence, Among Pediatric and Adult Medicaid Eligible Patients with Sickle Cell Disease in North Carolina

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 3391-3391
Author(s):  
Nirmish Shah ◽  
Christian Douglas ◽  
Nancy Crego ◽  
Emily Bonnabeau ◽  
Marian Earls ◽  
...  
Keyword(s):  
North Carolina ◽  
Sickle Cell Disease ◽  
Old Age ◽  
Sickle Cell ◽  
Research Funding ◽  
Acute Chest Syndrome ◽  
Age Group ◽  
Cell Disease ◽  
Good Adherence ◽  
Number Of Patients

Introduction: Sickle cell disease (SCD) is a complex disease for which pain is the hallmark. Hydroxyurea (HU) is the standard of care for treatment for most patients with SCD and reduces the frequency of pain episodes, acute chest syndrome, need for red blood cell transfusions, hospitalizations and has been shown to improve mortality. Despite National Heart Lung and Blood Institute (NHLBI) recommendations for the use of HU beginning at 9 months of age, adherence has been historically low. We aimed to: 1) describe HU prescription fills and adherence for persons with SCD enrolled in Medicaid during a 12-month period in North Carolina (NC); and 2) determine factors that may predict good adherence. Methods: Medicaid claims were examined from data obtained from Community Care of North Carolina (CCNC) for patients with a diagnosis of SCD (ICD 9 CM codes: 282.6x, ICD 10 CM codes: D57.0x, D57.1, D57.2x, D57.4x, D57.8x) between March 1, 2016 and February 28, 2017. HU claims were identified using the drug name. Only those enrolled in Medicaid for 12 months were included in this analysis. The number of HU prescriptions filled per enrollee by age group was determined by summing the number of filled HU prescriptions over the study period for each eligible enrollee. The number of HU days supplied is the sum of the days of supply on the prescription (e.g. 30-day supply) in a 12-month period per person. The duration of HU treatment days was measured as the number of days between the date of the first HU prescription filled and the last day of the study period. The number of days between breaks in treatment is the sum of days with no HU supplied, divided by the number of gaps (missing next HU prescription fill) per person. HU adherence was categorized into one of the followings: 1) Good - if number of days supplied is ≥80% of duration of HU treatment; 2) Fair or Moderate - if number of days supplied is 60-79% of duration of HU treatment; 3) Poor - if number of days supplied is < 60% of duration of HU treatment. Logistic regression was used to evaluate HU treatment adherence (good versus fair or poor). The model was conditioned on age, gender, participant residence (metro, non-metro adjacent to metro and non-metro non-adjacent to metro), co-management (at least one PCP and one hematologist visit/patient during the study period) and months enrolled in CCNC. Results: A total of 2,790 patients with Medicaid claims data were reviewed, with 649 patients meeting inclusion criteria (at least one HU prescription and 12 months enrollment in Medicaid). The participants in the sample were majority female (51.77%), lived in metropolitan areas (78.12%) and had a mean age of 16.49 years old (SD=11.49) A third of the sample (32.20%) had at least 1 HU prescription during the study period (Table 1). Those who were 1-9 years old had the highest median number of days supplied (221; range 21-750), the least median days between breaks in HU treatment (14.20; range 0-318), and the longest duration of HU treatment days (median 340; range 0-364). Those who were 18-30 years old had the lowest number of median days supplied (110; range 4-366) and the most median days between treatment (49.3; range 0-337). The 1-9 year olds also had the highest number of patients classified as good HU adherence (47.50%) and conversely the lowest classified as poor HU adherence (37.50%). In contrast, the 18-30 year old age group had the lowest good HU adherence (18.03%) and the highest poor HU adherence (69.40%) in the sample. The 31-45 year old age groups had the next lowest good HU adherence (20.93%) and next highest poor HU adherence (60.47%). Good HU adherence was most influenced by participant age. Prediction by co-management was minimal (Figure 1). Gender, residency and number of months enrolled in CCNC had little influence on HU adherence. Conclusions: Although recommended for most patients, HU was prescribed for less than one third of all patients with Medicaid in NC. Pediatric patients had the highest rate of HU prescription (40-46%) and patients over the age of 30 had the lowest (11-12%). In addition, of those prescribed HU, most patients were not classified as having good adherence. Importantly, poor HU adherence was most prevalent in the transition age group (18-30 year old), supporting the need for increased focus during the move from pediatric to adult care. Efforts should continue to explore methods that improve adherence including provider education and innovative patient strategies such as mHealth. Disclosures Shah: Alexion: Speakers Bureau; GBT: Research Funding; Novartis: Consultancy, Research Funding, Speakers Bureau. Tanabe:NIH: Research Funding; AHRQ: Research Funding.

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