Exhaled Carbon Monoxide as a Marker of Hemolysis In Transgenic Mouse Models of Sickle Cell Anemia.

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 1642-1642
Author(s):  
John D Belcher ◽  
Julia Nguyen ◽  
Julie Furne ◽  
Julie Vineyard ◽  
Joan Denise Beckman ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Sickle Cell Disease ◽  
Mouse Models ◽  
Normal Control ◽  
Sickle Cell ◽  
Research Funding ◽  
Cell Activation ◽  
Ischemia Reperfusion ◽  
Cell Disease ◽  
Free Heme

Abstract Abstract 1642 Sickle cell disease is characterized by recurring episodes of hemolysis and painful vasoocclusion, which leads to ischemia-reperfusion injury and organ damage. Recently, the roles of heme-induced oxidative stress, nitric oxide consumption, endothelial cell activation, and inflammation in sickle cell disease have been recognized, in part because of the development of transgenic murine models of this condition. These mouse models provide insights into the pathophysiology of human sickle cell disease and the development of new therapeutic approaches. However, hemolytic rates and disease severity vary considerably between mouse models. Ferrous (Fe2+) hemoglobin (Hb) is easily oxidized in circulation to ferric (Fe3+) Hb, which readily releases free heme. Free heme is degraded by heme oxygenase which produces carbon monoxide (CO) as a byproduct. Endogenous CO production has been used as a measure of in vivo hemolysis in humans and mice, but there have been no reports of endogenous CO production in sickle mouse models. VCO was measured in sickle mouse models using a previously described rebreathing technique t (Levitt et al. J Lab Clin Med 113:241-247). Expired CO levels were highest in Hb-S knock-in Townes-SS sickle mice, almost 7-fold higher than normal control Townes-AA mice (p<0.05). Expired CO also was significantly (p<0.05) higher in HbS-BERK mice compared to normal control HbA-BERK. Injection of phenylhydrazine or hemin into normal C57BL/6 mice also raised expired CO levels 24 hours after injection (p<0.05). Expired CO levels were not significantly higher than controls in the New York, S+S-Antilles, het-BERK and Townes-AS models. These data confirm that hemolytic rates differ markedly between models. Additional data will be presented on the effects of inhaled CO on expired CO and the hemolytic rate in the Townes-SS model. Disclosures: Belcher: Sangart: Consultancy, Research Funding. Vercellotti:Sangart: Consultancy, Research Funding.

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.

Keap1-Nrf2 System: Potential Role in Prevention of Sickle Cell Disease Organs Damages and Inflammation

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 411-411 ◽  
Author(s):  
Nadine Keleku-Lukwete ◽  
Mikiko Suzuki ◽  
Akihito Otsuki ◽  
Kouhei Tsuchida ◽  
Saori Katayama ◽  
...  
Keyword(s):  
Sickle Cell Disease ◽  
Sickle Cell ◽  
Ischemia Reperfusion ◽  
Organ Damage ◽  
The Other ◽  
Cell Disease ◽  
Indirect Bilirubin ◽  
Sickle Cells ◽  
Nrf2 Activation ◽  
Free Heme

Abstract Chronic hemolysis in sickle cell disease (SCD) gives rise to intermittent vessel occlusion. Recurrent ischemia-reperfusion generates high levels of reactive oxygen species (ROS) that leads to cell damage. On the other hand, lysed red blood cells (RBC) released free heme into blood stream, which contributes to generation of oxidant microenvironment. ROS burden generated by heme and ischemia-reperfusion injury contributes to endothelial cell activation that promotes inflammatory response with activation of inflammatory mediators. Sickle cell patients bearing high white blood cell (WBC) count develop severe complications of the disease. Nrf2 is a transcription factor that mediates adaptation to oxidative stress and cell defense. Under homeostatic conditions, Nrf2 is trapped by Keap1 and degraded by proteasome pathway. Upon exposure to stress stimuli, such as ROS and electrophiles, Nrf2 is stabilized and activates transcription of cytoprotective and antioxidants genes. Therefore, we hypothesized that Nrf2 activation might be important for tissue protection in SCD. To evaluate the therapeutic effect of Nrf2 activation on SCD, we used a SCD knock-in mouse model bearing human mutated globin loci. Since Keap1 negatively regulated Nrf2 in normal conditions, we crossed the SCD model mice with Keap1 hypomorphic knockdown (Keap1F/-) mice to generate compound mutant (SCD::Keap1F/-) mice, in which Nrf2 was constitutively activated. Histological analysis of the liver and lung revealed that congestive reaction and necrotic area observed in the SCD mice were significantly reduced in the SCD::Keap1F/- mice. Moreover, liver damage marker alanine transferase (ALT) were also decreased in SCD::Keap1F/- mice compared with SCD mice. We further examined inflammation status using human IL6 reporter mouse system and found that inflammation, which was mainly observed in lung of SCD mice, was markedly improved in the SCD::Keap1F/- mice. Expression levels of inflammatory cytokines IL6 and IL1β in the lung as well as adhesion molecules VCAM and P-selectin in the aorta of SCD::Keap1F/- mice were lower than those of the SCD mice. These results indicate that Nrf2 activation improves organ damage and inflammation in the SCD mice. On the other hand, hemolysis of sickle cells and compensatory stress erythropoiesis did not change substantially between the SCD and the SCD::Keap1F/- mice. These results indicate that Nrf2 activation improves organ damage and inflammation independently from improvement of hemolysis. Previous reports show that free heme released from sickle cells gives rise to ROS-mediate pathological process as inflammation and organ damage in SCD. We therefore measured plasma free heme and downstream product indirect bilirubin in the SCD::Keap1F/- mice, and found that both heme and indirect bilirubin was decreased in the SCD::Keap1F/- mice. These results demonstrate that Nrf2 activation improves SCD symptoms at least in part by elimination of free heme. To determine whether chemical compounds that serve as Nrf2 inducers have a protective potential of SCD mice organs, we treated 6-weeks aged mice with an Nrf2 inducer CDDO-Im (20 μmol/kg) 3 times per week for 3 weeks. CDDO-Im administration progressively reduced WBC numbers in the SCD::Keap1F/- mice. Also we observed decrease in the expression level of IL6 and IL1β in the lung and necrotic area in the liver in CDDO-Im-treated SCD::Keap1F/- mice. These results indicate that administration of a chemical Nrf2 inducer relieves inflammation and organ damage in the SCD mice. Collectively, these data provide the evidence that Nrf2 activation improves ROS-mediated organ damages and inflammation. Associated in the therapy of SCD, Nrf2 inducers could be of benefit to SCD patients. Disclosures No relevant conflicts of interest to declare.

Hospitalization for Acute Pain in Sickle Cell Disease: Changes in Clinical Parameters and Factors Predicting Hospital Discharge and Re-Admission

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 3662-3662
Author(s):  
Mehdi Nouraie ◽  
Debra L Weiner ◽  
Mariana Hildesheim ◽  
Ward Hagar ◽  
Oswaldo L Castro ◽  
...  
Keyword(s):  
Steady State ◽  
Sickle Cell Disease ◽  
Hospital Stay ◽  
Sickle Cell ◽  
Research Funding ◽  
Ischemia Reperfusion ◽  
Serum Lactate Dehydrogenase ◽  
Index Hospitalization ◽  
Cell Disease ◽  
Readmission Risk

Abstract Introduction: Acute vaso-occlusive crisis (VOC) is the hallmark clinical complication of sickle cell disease (SCD). VOC involves several mechanisms, including rigid erythrocytes, adhesive blood cells, activated coagulation, activated and dysregulated endothelium, inflammation, and ischemia-reperfusion injury. Surprisingly few data document clinical and laboratory markers that change from steady state to VOC and during the hospital stay, and that predict subsequent rehospitalization. We characterized such markers in this study. Methods: Data were collected as part of a clinical trial of nitric oxide as potential treatment for VOC (DeNOVO). Participants, age ≥ 10 years requiring hospitalization for VOC, were recruited from 11 academic medical centers at the time of VOC. Length of hospital stay (LOS), change in visual analogue scale (VAS) pain score, and hospital readmission within 30 days were study outcomes. Steady state laboratory values were available in a subgroup of patients for comparison. Differences between admission and steady state laboratory measures and changes in clinical and laboratory parameters from hospital admission to discharge were analyzed by Wilcoxon signed-rank test. Multivariate linear and logistic regression analyses were used to identify the independent predictors of LOS and 30-day readmission risk. Results: 150 recruited patients had a median (interquartile range; IQR) age of 24 (17-33) years; 50% were female, and 91% had HbSS genotype. The median VAS score at time of admission was 7.7 cm which subsided to 3.3 cm at time of discharge (P &lt;0.001). Serum lactate dehydrogenase concentrations (LDH) and neutrophils counts increased from steady state to the time of the VOC (P ≤ 0.001) and then decreased during the hospital stay (P ≤ 0.01) (Figure). The median (IQR) LOS was 3.5 (1.9-6.0) days. Longer LOS was predicted by higher admission VAS and serum alkaline phosphatase level, as well as higher increase in respiratory rate during hospital stay (P ≤ 0.006) (Table). The rate of 30-day hospital/ED readmission was 24%. Longer LOS was associated with lower risk of readmission (OR = 0.65, 95% CI: 0.50-0.86 per day). Other risk factors for readmission were higher serum creatinine at discharge (OR = 5.54, 95% CI: 1.12-27.51 per mg/dL), greater increase in serum alanine aminotransferase (OR = 1.03, 95%CI: 1.01-1.06 per unit increase) and greater cumulative opioid doses (OR = 1.25, 95%CI: 1.11-1.49 per 100 mg) during the index hospitalization. Conclusion: VOC is associated with neutrophilia and increased LDH, consistent with inflammation and hemolysis and/or tissue injury, although of insufficient magnitude to be used as diagnostic criteria. The magnitude of pain and marker of apparent bone involvement predict longer LOS. SCD patients with VOC carry a high burden of readmission risk, which is characterized by higher opioid utilization and earlier discharge from the index hospitalization. These concepts can shape models, especially to reduce readmission rate, to be evaluated in prospective clinical trials. *First two authors contributed equally to this work. Figure Figure. Table Table. Disclosures Lanzkron: NKT: Research Funding; Selexys: Research Funding; Prolong: Research Funding; PCORI: Research Funding; NHLBI: Research Funding; HRSA: Research Funding; GBT: Consultancy; Pfizer: Research Funding.

scholarly journals Nrf2 activation in myeloid cells and endothelial cells differentially mitigates sickle cell disease pathology in mice

2019 ◽  
Vol 3 (8) ◽  
pp. 1285-1297 ◽  
Author(s):  
Nadine Keleku-Lukwete ◽  
Mikiko Suzuki ◽  
Harit Panda ◽  
Akihito Otsuki ◽  
Fumiki Katsuoka ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Sickle Cell Disease ◽  
Sickle Cell ◽  
Vascular Function ◽  
Cell Activation ◽  
Ischemia Reperfusion ◽  
Globin Gene ◽  
Cell Disease ◽  
Cell Counts ◽  
Nrf2 Activation

Abstract Sickle cell disease (SCD) is caused by a monogenic mutation of the β-globin gene and affects millions of people worldwide. SCD is associated with sustained hemolytic anemia, vasoocclusion, ischemia-reperfusion injury, oxidative tissue damage, inflammatory cell activation, and systemic endothelial dysfunction. The transcription factor Nrf2 coordinates the expression of a wide variety of genes encoding antioxidant, detoxification, and metabolic enzymes. Nrf2 participates in suppressing proinflammatory cytokines and organ protection in SCD. However, little is known regarding the mechanisms by which Nrf2 ameliorates SCD pathology or how some cells respond to Nrf2 stimuli to alleviate SCD pathology. Here, we asked whether monocytes/granulocytes and/or endothelial cells are particularly critical in alleviating the pathology of SCD. By targeting these cells with a Cre recombinase system, we generated SCD::Keap1F/F::LysM-Cre and Tie1-Cre mice with constitutive Nrf2 activation in monocytes/granulocytes and endothelial cells, respectively. Analyses of SCD::Keap1F/F::LysM-Cre and SCD::Keap1F/F::Tie1-Cre mice revealed significantly reduced inflammation, along with decreased white blood cell counts and lower Tnfα and Il1β expression in the lungs. Notably, SCD::Keap1F/F::LysM-Cre mice exhibited reduced heme distribution in the liver, consistent with a decrease in the damaged areas. Vascular function in SCD::Keap1F/F::Tie1-Cre mice was significantly improved, with a 50% decrease in vascular leakage and low expression of the adhesion molecules Vcam1 and P-selectin. Thus, Nrf2 activation in monocytes/granulocytes and endothelial cells contributes differentially and cooperatively to the improvement of SCD pathology.

scholarly journals Targeting pain at its source in sickle cell disease

2018 ◽  
Vol 315 (1) ◽  
pp. R104-R112 ◽  
Author(s):  
Kanika Gupta ◽  
Om Jahagirdar ◽  
Kalpna Gupta
Keyword(s):  
Sickle Cell Disease ◽  
Sickle Cell ◽  
Cell Activation ◽  
Molecular Mechanisms ◽  
Genetic Disorder ◽  
Somatosensory System ◽  
Organ Damage ◽  
Mast Cell Activation ◽  
Cell Disease ◽  
Central Nervous Systems

Sickle cell disease (SCD) is a genetic disorder associated with hemolytic anemia, end-organ damage, reduced survival, and pain. One of the unique features of SCD is recurrent and unpredictable episodes of acute pain due to vasoocclusive crisis requiring hospitalization. Additionally, patients with SCD often develop chronic persistent pain. Currently, sickle cell pain is treated with opioids, an approach limited by adverse effects. Because pain can start at infancy and continue throughout life, preventing the genesis of pain may be relatively better than treating the pain once it has been evoked. Therefore, we provide insights into the cellular and molecular mechanisms of sickle cell pain that contribute to the activation of the somatosensory system in the peripheral and central nervous systems. These mechanisms include mast cell activation and neurogenic inflammation, peripheral nociceptor sensitization, maladaptation of spinal signals, central sensitization, and modulation of neural circuits in the brain. In this review, we describe potential preventive/therapeutic targets and their targeting with novel pharmacologic and/or integrative approaches to ameliorate sickle cell pain.

scholarly journals Engineering, Generation and Preliminary Characterization of a Humanized Porcine Sickle Cell Disease Animal Model

2020 ◽  
Author(s):  
Tobias M. Franks ◽  
Sharie J. Haugabook ◽  
Elizabeth A. Ottinger ◽  
Meghan S. Vermillion ◽  
Kevin M. Pawlik ◽  
...  
Keyword(s):  
Animal Model ◽  
Sickle Cell Disease ◽  
Mouse Models ◽  
Sickle Cell ◽  
Cell Model ◽  
Globin Genes ◽  
Cell Disease ◽  
Small Vessels

AbstractMouse models of sickle cell disease (SCD) that faithfully switch from fetal to adult hemoglobin (Hb) have been important research tools that accelerated advancement towards treatments and cures for SCD. Red blood cells (RBCs) in these animals sickled in vivo, occluded small vessels in many organs and resulted in severe anemia like in human patients. SCD mouse models have been valuable in advancing clinical translation of some therapeutics and providing a better understanding of the pathophysiology of SCD. However, mouse models vary greatly from humans in their anatomy and physiology and therefore have limited application for certain translational efforts to transition from the bench to bedside. These differences create the need for a higher order animal model to continue the advancement of efforts in not only understanding relevant underlying pathophysiology, but also the translational aspects necessary for the development of better therapeutics to treat or cure SCD. Here we describe the development of a humanized porcine sickle cell model that like the SCD mice, expresses human ɑ-, β− and γ-globin genes under the control of the respective endogenous porcine locus control regions (LCR). We also describe our initial characterization of the SCD pigs and plans to make this model available to the broader research community.

scholarly journals COVID Symptoms and COVID Anxiety in Sickle Cell Disease

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 16-17
Author(s):  
Wally R Smith ◽  
Benjamin Jaworowski ◽  
Shirley Johnson ◽  
Thokozeni Lipato ◽  
Daniel M Sop
Keyword(s):  
Sickle Cell Disease ◽  
Sickle Cell ◽  
Research Funding ◽  
Telephone Survey ◽  
Cell Disease ◽  
Weighted Mean ◽  
The Us ◽  
Associated Symptoms ◽  
At Home

Background Even before the US upswing of the current COVID pandemic, the number of sickle cell disease (SCD) patients coming to hospitals and EDs appeared to fall drastically. This happened despite SCD patients having often been heavy utilizers of the ED and hospital for their iconic vaso-occlusive crises (VOC). Though ambulatory SCD clinics quick converted largely to telehealth in order to comply with stay-at-home orders designed to suppress person-to-person transmission, some SCD patients appeared to avoid care, delay care, or refuse doctors' invitations for care. Presumably patients did so out of COVID fears, but this has not been confirmed in the literature. Further, whether these patients had COVID symptoms but stayed at home has not been studied. As part of quality improvement (QI) to conduct COVID surveillance in an adult sickle cell program, we sought to explain and predict SCD health care utilization patterns we were observing, as well as to determine urgent physical and mental health needs of patients who appeared to be avoiding care. Methods Fifteen staff in the Adult Sickle Cell Medical Home at Virginia Commonwealth University, a large urban academic medical center, conducted a telephone survey ("wellness check"was used when we talked to patients) of all known adults with SCD over 19 days in 2020. A staff member confirmed the patient had SCD, asked permission to proceed, then asked about symptoms consistent with COVID-19. At the end of the telephone survey, respondents wer invited to complete an email survey of sickle cell and COVID-19 utilization attitudes (19-33 items, depending on the response pattern, either drawn from the National Health Interview Survey, from the Adult Sickle Cell Quality of Life Measurement quality of care survey, or drafted by the authors), the Sickle Cell Stress Survey-Adult (SCSS-A, a 10-item previously validated survey), and anxiety and depression (PHQ9 of the PRIME-MD). Results Of 622 adults approached by phone call, 353 responded to the following yes/no screening questions regarding the prior 14 days: fever over 100 F 0/353 (0.00%); cough 3/353(0.01%); difficulty breathing 0/353(0.00%); unexplained shortness of breath 2/353(0.01%); sore throat 2/353 (0.01%); unexplained muscle soreness 2/353(0.01%);contact with anyone who tested positive for COVID-19 2/353(0.01%); testing for COVID 19 6/353(0.02%). For QI purposes, we set a threshold of three or more COVID-associated symptoms or the presence of fever as criteria requiring intense telephone or in-person staff monitoring for the following week. Only three patients met criteria. A total of 219/353 had email surveys sent. Of 63 patients (28.8%) who returned email surveys by June 10, 2020, 35.9% had already managed a "pain attack" at home 4 or more times in the prior 12 months, and 45.5% of these said their bad ER experiences were very or somewhat important in that decision. In the prior 14 days, although 30/64 reported a crisis for at least one day, only 4/64 had visited the Emergency Department for pain. On a 0-10 scale, 21/61 patients endorsed "0" for worry that they would be COVID-infected by going for medical care (weighted mean 3.9), but 18/59 endorsed "10" for worry they were more at risk of COVID because of SCD (weighted mean 6.31), and 22/60 endorsed "10" for worry they would fare worse than others if COVID infected (weighted mean 6.97). Many patients forwent "needed" care (16/62) or delayed "needed" care by at least a day (36/61). Eleven patients met criteria for moderately severe to severe depression on the PHQ-9, and 28/63 somewhat or strongly agreed with the statement "death is always on the back of my mind" on the SCSS-A. Conclusions In adolescents and adults with SCD, many were already reticent to come to the ED for pain, but a significant portion reported delays or avoidance of needed care during the early stages of the US COVID pandemic, and few reported using the ED despite over half reporting at least one crisis day in 14. Patients nonetheless reported very few COVID-associated symptoms. Fears of COVID infection/susceptibility may limit visits for needed sickle cell care among adults. Acknowledgements: Mica Ferlis RN, FNP, Caitlin McManus, RN, FNP, Emily Sushko, RN, FNP, Justin West, RN, Kate Osborne, RN, Stefani Vaughan-Sams, Marla Brannon, BS, Nakeiya Williams, BS Disclosures Smith: GlycoMimetics, Inc.: Consultancy; Emmaeus Pharmaceuticals, Inc.: Consultancy; Novartis, Inc.: Consultancy, Other: Investigator, Research Funding; Global Blood Therapeutics, Inc.: Consultancy, Research Funding; Shire, Inc.: Other: Investigator, Research Funding; NHLBI: Research Funding; Patient-Centered Outcomes Research Institute: Other: Investigator, Research Funding; Health Resources and Services Administration: Other: Investigator, Research Funding; Incyte: Other: Investigator; Pfizer: Consultancy; Ironwood: Consultancy; Novo Nordisk: Consultancy; Imara: Research Funding; Shire: Research Funding.

scholarly journals Clinical and Biomarker Predictors for Avascular Necrosis in Sickle Cell Disease

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 3091-3091
Author(s):  
Michael Rabaza ◽  
Maria Armila Ruiz ◽  
Liana Posch ◽  
Faiz Ahmed Hussain ◽  
Franklin Njoku ◽  
...  
Keyword(s):  
Risk Factors ◽  
Sickle Cell Disease ◽  
Board Of Directors ◽  
Avascular Necrosis ◽  
Sickle Cell ◽  
Research Funding ◽  
Medical Attention ◽  
Cell Disease ◽  
Advisory Committees ◽  
Early Management

Abstract Introduction Sickle cell disease (SCD) affects 1 in 365 African Americans and approximately 25 million people world-wide. A common skeletal system complication is avascular necrosis (AVN), which can cause substantial pain and a reduced quality of life. While early management of AVN is focused on increasing range of motion with physical therapy and pain relief, there are no clear predictors for who is more likely to develop AVN and earlier institution of these preventive measure could help decrease disease progression. Vascular endothelial growth factor (VEGF) is a biomarker of endothelial injury and may indicate reduced vascular supply to the femoral or humeral head. Here we describe potential risk factors and biologic pathways for AVN in SCD, as understanding these may lead to improvements in future monitoring, early detection, and early intervention practices. Methods We investigated clinical and laboratory risk factors associated with AVN in a cohort of 435 SCD patients from our center. Blood samples, clinical, and laboratory data were collected at the time of enrollment during a clinic visit. Genotyping for alpha thalassemia was performed by PCR and the serum concentration of VEGF was measured by ELISA. AVN status was confirmed by review of the medical record and available imaging. We conducted a cross-sectional analysis comparing categorical and linear variables by AVN status using the chi-square and Kruskal-Wallis test, respectively. The independent association of the clinical and laboratory variables with AVN status was determined by logistic regression analysis. The initial model included variables with a P-value &lt; 0.1 on univariate analysis and the final model was ascertained by stepwise forward and backward selection. Median values and interquartile range (IQR) are provided. Results The median age of the cohort was 32 (IQR, 24 - 43) years, 57% (250/435) were female, and 46% (198/435) were on hydroxyurea. AVN was observed in 34% (149/435) of SCD patients. SCD patients with AVN were older, had more frequent vaso-occlusive crises requiring medical attention, and had a higher body mass index (Table I) (P ≤ 0.002). We measured VEGF in 241 of the SCD patients with serum samples available at the time of enrolment. Serum VEGF concentrations trended higher in SCD patients with versus without AVN (420 vs. 359 pg/mL, respectively; P = 0.078). In the multivariate analysis model, AVN was independently associated with increased number of vaso-occlusive crises (OR 1.1, 95% CI: 1.0 - 1.14; P = 0.02), AST concentration (natural log OR 0.5, 95% CI: 0.2 - 0.9; P = 0.03), VEGF concentration (natural log OR 1.4, 95% CI: 1.0 - 1.9; P = 0.047), and tobacco use (OR 1.9, 95% CI: 0.9 - 3.7; P = 0.078). Discussion In conclusion, we demonstrate a high prevalence of AVN in an adult cohort of SCD patients. The presence of AVN was independently associated with a greater frequency of vaso-occlusive pain episodes, which may demonstrate a shared pathophysiology between AVN and vaso-occlusion that merits further investigation. We demonstrate that serum VEGF concentrations are higher in SCD patients with AVN and may be a clinical tool to identify those at high-risk and for earlier intervention for this complication. Figure 1 Figure 1. Disclosures Gordeuk: Modus Therapeutics: Consultancy; Novartis: Research Funding; Incyte: Research Funding; Emmaus: Consultancy, Research Funding; Global Blood Therapeutics: Consultancy, Research Funding; CSL Behring: Consultancy. Saraf: Pfizer: Research Funding; Global Blood Therapeutics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding.

scholarly journals Alkaline Phosphatase Is Associated with Red Cell Alloimmunization in the Pulmonary Hypertension and Hypoxic Response (PUSH) Sickle Cell Disease Cohort

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 20-20
Author(s):  
Victoria Brooks ◽  
Oluwalonimi Adebowale ◽  
Victor R. Gordeuk ◽  
Sergei Nekhai ◽  
James G. Taylor
Keyword(s):  
Risk Factors ◽  
Alkaline Phosphatase ◽  
Sickle Cell Disease ◽  
Sickle Cell ◽  
Research Funding ◽  
Severe Disease ◽  
Case Control ◽  
Red Cell ◽  
Cell Disease ◽  
History Of

Background: Blood transfusion is a common therapy for sickle cell disease (SCD). Although, highly effective, a major limitation is development of alloantibodies to minor blood group antigens on donor red cells. Alloimmunization has a prevalence of 2-5% for transfusions in the general population, but it is significantly higher in SCD. Risk factors for alloimmunization have been poorly characterized, although number of lifetime transfusions is an important risk factor. Alloimmunization has been clinically observed in children with a prevalence of about 7%. With development of each antibody, blood donor matching becomes increasingly difficult and expensive with an increased risk for transfusion reactions and diminished availability of compatible red cell units for treatment of SCD. The ability to identify risk factors for developing alloantibodies would be beneficial for clinicians. To identify markers for alloimmunization in SCD, we have analyzed children and adults who developed this complication. Methods: We analyzed The Pulmonary Hypertension and Hypoxic Response in Sickle Cell Disease (PUSH) study, which enrolled n=468 pediatric and n=59 adult SCD subjects. In both children and adults, alloimmunization cases were defined as a history of at least 1 alloantibody. Controls in both cohorts were defined as subjects with no history of alloantibodies and receipt of more than 10 lifetime red cell transfusions. All others within the study who did not meet these criteria were assigned to a third comparison group. To identify differences between cases, controls and all others, we performed univariate analyses (using ANOVA or Kruskal Wallace where appropriate) for clinical parameters and laboratories. Case control comparisons were also performed for selected variables and plasma levels for 11 cytokines. Results were further analyzed using regression modeling. Results: The overall prevalence of alloimmunization was 7.3% among children (34/468 subjects; median age 12, range 3-20 years) compared to 28.8% in adults (17/59 subjects; median age 37, range 18-73 years). When only considering those with &gt;10 lifetime transfusions, the prevalence was considerably higher at 29.3% and 54.8% in children and adults, respectively. At the same time, 8 pediatric (23.5%) and 5 adult (29.4%) alloimmunization cases had received fewer than 10 transfusions. In a 3-way pediatric cohort comparison (cases, controls and all others), risk factors associated with alloimmunization included SS genotype, older age and markers of more severe disease (higher ferritin, WBCs, platelets and total bilirubin). Comparison of cases to controls showed alkaline phosphatase (P=0.05) was significantly lower in cases, whereas AST (P=0.02) was significantly higher even with adjustment for age. Levels of plasma cytokines MCP-1 (P=0.01) and IFNgamma (P=0.08) were lower in cases from a subset of the pediatric cohort. In adults, only 4/59 (6.8%) subjects had never received a lifetime transfusion (all non-SS). In the adult 3-way comparisons, only SS genotype and higher ferritin were associated with alloimmunization. The adult case control analysis showed higher absolute monocyte count (P=0.02), absolute eosinophil count (P=0.04) and absolute basophil count (P=0.008) in association with alloimmunization cases. In addition, alkaline phosphatase was again significantly lower among cases (P=0.02) as seen in the pediatric cohort. There were no significant differences in cytokine levels among adults. Conclusions: When considering only transfused SCD patients, the prevalence of alloimmunization is higher than 30%. As seen in prior studies, higher lifetime red cell transfusions are an important risk factor especially among adults where most patients have received transfusions. Children who develop alloantibodies appear to have laboratory markers of more severe disease, but this is not observed in adults. A novel association observed across both pediatric and adult subjects is a significantly lower serum alkaline phosphatase in those with alloantibodies. The results of this study suggest a need for improved tracking of red cell transfusion therapy in the US for SCD patients due to a high prevalence of alloimmunization. Further study is also needed to elucidate the significance of the alkaline phosphatase association. Disclosures Gordeuk: CSL Behring: Consultancy, Research Funding; Global Blood Therapeutics: Consultancy, Research Funding; Novartis: Consultancy; Ironwood: Research Funding; Imara: Research Funding.

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