scholarly journals The Therapeutic Modalities of Sickle Cell Disease Reprogram the Platelet Functional-Bioenergetic Profile

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 957-957
Author(s):  
Orlando Esparza ◽  
Giovanny Hernandez ◽  
Rachelle Nuss ◽  
David Irwin ◽  
Marguerite Kelher ◽  
...  

Abstract BACKGROUND: Sickle cell disease (SCD) is a group of inherited hemoglobinopathies that continues to be highly morbid and lethal. SCD-associated platelet hyperreactivity is a well-recognized contributor to the pathophysiology of the disease via complex interactions with the immune system and endothelium. Aberrant platelet bioenergetics have been implicated as a biological mechanism for SCD-associated platelet hyperreactivity, however, little is known about the impact current medical interventions (e.g., hydroxyurea [HU] and red blood cell [RBC] exchange transfusions) have on the platelet functional-bioenergetic profile. In this study we investigate the effects of hydroxyurea and RBC exchange transfusions on reprograming the platelet functional-bioenergetic profile and provide insight into biological pathways that may be amenable to intervention. METHODS: Platelets from sex-, race-, and aged-matched adult healthy control subjects and adult patients with homozygous SCD (HbSS), actively being treated with hydroxyurea (HU group) or RBC exchange transfusions (RBC exchange transfusion group), were isolated and washed following standard protocols. Platelet activation by flow cytometry was determined at baseline and following activation with thrombin (0.075U/ml) and ADP (1.25uM). Platelet-activated fibrinogen binding site (αIIbβIII), P-selectin, and phosphatidylserine (PS) surface marker expression (as measured by mean fluorescence intensity [MFI]) was determined with PAC-1, P-selectin, and lactadherin antibodies, respectively. The bioenergetic profile of washed platelets was determined by the 24-well format Seahorse extracellular flux analyzer. Statistical analyses were performed using the one-way ANOVA. Correlations were performed by 2-tailed nonparametric Spearman correlations and linear regression analysis with 95% confidence interval (GraphPad Software v9.1.2). Data expressed as mean plus or minus standard error of the mean (SEM). Differences were considered significant at p < 0.05. RESULTS: Platelets from patients in the HU group exhibited increased surface marker expression of αIIbβIII (p = 0.004), P-selectin (p = 0.003), and PS (p = 0.003) at resting conditions when compared to the RBC exchange transfusion group and healthy controls. Additionally, an increase in PS expression was seen in the HU group upon activation with ADP (p = 0.0003). No significant differences were seen in the platelet functional profile after activation with thrombin. The platelet bioenergetic profile in the HU group demonstrated an elevated proton leak (p = 0.03) when compared to the RBC exchange transfusion group. Elevated proton leak in SCD was found to have positive correlation with P-selectin and PS expression (Figure 1). CONCLUSION: While therapeutic interventions have improved overall outcomes in patients with SCD, adverse events continue to be a deterrent to many patients prompting the need for safer, more tolerable, and cost-effective alternatives. We have identified that while HU has little impact on the hyperreactive and procoagulant platelet phenotype in SCD, RBC exchange transfusions appear to mitigate the phenotype and reprogram the bioenergetic profile. Amongst treatment groups, a strong correlation was found between platelet activation markers (i.e., P-selectin and PS) and proton leak, suggesting an interplay between alterations in platelet bioenergetics and SCD-associated platelet hyperreactivity. Further studies are needed to elucidate the metabolic pathways that are responsible for the aberrant platelet functional-bioenergetic profile seen in SCD. These observations are important as targeting the platelet bioenergetic profile via less invasive and toxic therapeutic modalities may be equally efficacious as current interventions. Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.

Author(s):  
Susanna A. Curtis ◽  
Balbuena-Merle Raisa ◽  
John D. Roberts ◽  
Jeanne E. Hendrickson ◽  
Joanna Starrels ◽  
...  

Blood ◽  
2015 ◽  
Vol 125 (22) ◽  
pp. 3401-3410 ◽  
Author(s):  
Adetola A. Kassim ◽  
Najibah A. Galadanci ◽  
Sumit Pruthi ◽  
Michael R. DeBaun

Abstract Neurologic complications are a major cause of morbidity and mortality in sickle cell disease (SCD). In children with sickle cell anemia, routine use of transcranial Doppler screening, coupled with regular blood transfusion therapy, has decreased the prevalence of overt stroke from ∼11% to 1%. Limited evidence is available to guide acute and chronic management of individuals with SCD and strokes. Current management strategies are based primarily on single arm clinical trials and observational studies, coupled with principles of neurology and hematology. Initial management of a focal neurologic deficit includes evaluation by a multidisciplinary team (a hematologist, neurologist, neuroradiologist, and transfusion medicine specialist); prompt neuro-imaging and an initial blood transfusion (simple followed immediately by an exchange transfusion or only exchange transfusion) is recommended if the hemoglobin is >4 gm/dL and <10 gm/dL. Standard therapy for secondary prevention of strokes and silent cerebral infarcts includes regular blood transfusion therapy and in selected cases, hematopoietic stem cell transplantation. A critical component of the medical care following an infarct is cognitive and physical rehabilitation. We will discuss our strategy of acute and long-term management of strokes in SCD.


2020 ◽  
Vol 154 (Supplement_1) ◽  
pp. S100-S101
Author(s):  
S S Karimi ◽  
H Ni ◽  
L L Hsu

Abstract Introduction/Objective Voxelotor is a molecule that allosterically binds to the alpha-chain of hemoglobin, resulting in increased oxygen affinity. This allosteric inhibition leads to prevention of hemoglobin polymerization and sickling of red blood cells in response to low oxygen tension. Voxelotor has been used to treat patients with Sickle Cell Disease (SCD) and recent literature indicates it may contribute to complex hemoglobin fractionation (HF) elution patterns. We report a novel case of a SCD patient on concurrent Hydroxyurea, Voxelotor and chronic RBC exchange transfusion treatment and discuss the implications of these three treatment modalities on HF and monitoring of SCD. Methods A 17-year-old female with SCD complicated by frequent vaso-occlusive crisis, and avascular necrosis managed with chronic RBC exchange and Hydroxyurea. Her HF prior to initiation of Voxelotor treatment showed 3.2% HbA2, 51% HbA, 6.0% HbF, and 41% HbS. Voxelotor therapy was initiated at 1500mg/day and HF was performed 10 days later. Whole blood was collected and subjected to High Performance Liquid Chromatography (HPLC) with reflex to RBC solubility and Capillary Electrophoresis. Results HF performed post-Voxelotor therapy revealed positive sickle solubility with a complex pattern of 2.7% HbA2, 49.2% HbA, 5.3% HbF, 15.7% HbS, 0% HbC, and two additional peaks of a 6.3% peak in the window-D region (retention time of 4.34) and 20.8% of an atypical Hb peak pattern (at the retentuin time of 4.18). The results reflected a complex HF of a HbSS patient on concurrent chronic RBC exchange transfusion, hydroxyurea therapy, and Voxelotor treatment. Post Voxelotor-therapy HF revealed a reduction in HbS from 41% to 15.7% with the emergence of two additional peaks. Chronic RBC exchange transfusion and Hydroxyurea treatment account for the observed fractionation of HbA and HbF, respectively. Based on recent literature, we attribute the emergence of the two additional peaks to Voxelotor therapy. All three therapies led to reduction in HbS. Conclusion Routine HF serves as an essential modality in diagnosis and monitoring of SCD. Voxelotor treatment alters the HF profile and may cause difficulty for interpretation. With the emergence of novel therapies, it is imperative for clinicians to provide medication information to clinical laboratories and pathologists to be fully aware of the effects of current treatments to correctly interpret and monitor SCD.


Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 4822-4822
Author(s):  
Aref Agheli ◽  
Kirshma Khemani ◽  
Madhumati Kalavar ◽  
William Steier ◽  
Zili He

Abstract Background: The pathophysiology of sickle cell disease (SCD) is based on increased blood viscosity due to abnormal red blood cells (RBCs), which causes SCD complications, such as chronic hemolytic anemia, vaso-occlusive crisis with tissue hypoxemia, and organ dysfunction. Effective treatment of Sickle Cell Anemia is to reduce the blood concentration of Hemoglobin S (Hb S) RBCs. Exchange transfusion (ET) remains an effective but possibly underutilized therapy for the management of various acute and chronic complications of SCD such as acute chest syndrome, thromboembolic stroke, splenic and hepatic infarction, right upper quadrant syndrome, multi-organ failure syndrome, or in preparation for surgery by reducing HbS to less than 30%. RBC ET quickly replaces abnormal RBCs with normal RBCs, thus improving oxygen transport while reducing overall blood viscosity. Methodology: To determine the effectiveness of ET in SCD in reducing the total number of admissions and total in-hospital Length of Stay (LOS) in patients, admitted with any of acute complications of SCD, we retrospectively reviewed the medical records of 38 patients between June 15, 2007 and June 15, 2008. The eligibility criteria were age above 18 years old and admission to the hospital for any SCD complication. Nineteen patients had ET with Hb A containing RBCs, generally with an average packed RBC exchange volume of 70–80 ml/kg patient’s weight. Nineteen patients were treated with conventional managements. Three patients were excluded from the ET group because of prolonged LOS due to non-SCD- related complications. Four patients in the non-Exchange group signed against medical advice on the first day of admission and were excluded from analysis. Results: Sixteen (42.1%) patients were male and 22 (57.9%) patients were female. Their ages ranged from 19 to 67 years old, mean (SD) 30.2 (10.8). Of eligible patients, 19 (50%) patients received at least one therapeutic ET during the one year period of the study. In an independent-Samples T test analysis, the mean (SD) LOS were 7.5 (0.6) and 4.2 (0.6) days for the groups without ET and with ET respectively (95% CI = −5.2 to 1.5, p=.0011) (Figure 1). In this small studied group, this resulted average 3.3 days shorter in-hospital stay in ET group, could have saved 62 in-hospital days in the group who received conventional treatments. This number could have been easily much greater, since our hospital’s electronically stored data revealed that during year 2007, there had been 278 SCD admissions in all age groups. There was no mortality in the ET group, nor were any transfusion-related complications reported. In another analysis of one year follow up data, the number of admissions for the patients who never received ET ranged from 1 to 14, mean (SD) 1.7 (2.3) times in year 2007, while in patients who received at least one ET, the number of following admissions ranged from 0 to 2, mean (SD) 0.7 (1.3) times during the next year (95% CI = 0.16 to 1.7, p= .020). Hemoglobin level of patients in conventional treatment group on the day of discharge ranged from 6.5 to 10.7, mean (SD) 8.9 (1.9) and in ET group it ranged from 8.4 to 12.4, mean (SD) 10.2 (1.2) gr/dl (p= .045). Conclusion: Patients with SCD are frequently admitted to hospital for vaso-occlusive crisis and other complications. Exchange transfusion is a reliable, safe, and effective therapeutic modality in SCD patients, in particular during a catastrophic event. ET can significantly reduce the number of hospital admissions and in-hospital stay days in these patients. In addition, patients managed with ET have a better hemoglobin level on discharge. Figure Figure


Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 1049-1049
Author(s):  
Joseph A. Jakubowski ◽  
Chunmei Zhou ◽  
David S. Small ◽  
Kenneth J. Winters ◽  
D. Richard Lachno ◽  
...  

Abstract Abstract 1049 Introduction: Evidence suggests that platelets are activated in sickle cell disease (SCD) and this appears to increase further during painful crises caused by vascular occlusions from sickled red blood cells. Antiplatelet therapy may be useful in reducing the frequency and severity of acute pain episodes and reducing the risk of thrombotic complications. Prasugrel, an ADP receptor antagonist, irreversibly inhibits the P2Y12 ADP receptor, blocking ADP-stimulated platelet activation and aggregation and reducing downstream procoagulant activities. Here we present the first evaluation of prasugrel's effects on markers of in vivo platelet activation and of coagulation in subjects with SCD. Methods: Twenty-six adult subjects were enrolled and 25 completed the study: 12 with SCD and 13 well-matched healthy controls. Subjects were examined before and after 12±2 days of treatment with oral prasugrel (5.0 mg/day for subjects weighing <60 kg and 7.5 mg/day for subjects weighing ≥60 kg). Markers of platelet activation and coagulation included whole-blood platelet-monocyte and -neutrophil aggregates, and whole blood platelet-associated P-selectin and platelet CD40L, all measured by flow cytometry and presented as percent (%) of marker positive cells. Plasma soluble (s) P-selectin, CD40L, and plasma prothrombin fragment 1.2 (F1.2) were evaluated by ELISA. Results: Results from the biomarkers are presented in the table. Prior to prasugrel administration (baseline), subjects with SCD had significantly higher levels of the following biomarkers compared to healthy subjects: Platelet-monocyte aggregates, platelet-neutrophil aggregates, platelet CD40L, and plasma F1.2. In addition, subjects with SCD had numerically higher values of sCD40L, as well as platelet-associated and sP-selectin. Prasugrel treatment resulted in numerical decreases in levels of all biomarkers (with the exception of platelet-associated CD40L for control subjects), most notably in SCD subjects with elevated baseline levels. Prasugrel was safe and well tolerated with no serious adverse events observed during the study. No subject discontinued the study due to an adverse event (AE) and the majority of AEs were mild. No subjects with SCD reported any bleeding-related AEs. Conclusion: In this study, compared to healthy controls, baseline elevation of several platelet-activation and coagulation markers among adult subjects with SCD is consistent with that seen in previous studies of both children and adults with SCD. The decrease in platelet activation biomarkers following 12 days of prasugrel treatment in subjects with SCD suggests prasugrel interrupts SCD-related platelet activation in vivo and raises the possibility that prasugrel may modulate the frequency and/or severity of painful crises associated with SCD. These data support additional studies of the safety and efficacy of prasugrel in the treatment of vascular complications associated with SCD. Disclosures: Jakubowski: Eli Lilly and Company: Employment, Equity Ownership. Off Label Use: This abstract discusses prasugrel treatment in patients with sickle cell disease. Please see USPI for most up-to-date information. Zhou:Eli Lilly and Company: Employment, Equity Ownership. Small:Eli Lilly and Company: Employment, Equity Ownership. Winters:Eli Lilly and Company: Employment, Equity Ownership. Lachno:Eli Lilly and Company: Employment, Equity Ownership. Frelinger:Takeda: Research Funding; Daiichi Sankyo Company, Ltd. and Eli Lilly and Company: Consultancy, Research Funding; GLSynthesis: Research Funding. Howard:Daiichi Sankyo Company, Ltd. and Eli Lilly and Company: Research Funding. Payne:Eli Lilly and Compnay: Employment, Equity Ownership.


Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 4091-4091
Author(s):  
Laurence Dedeken ◽  
Phu Quoc Lê ◽  
Laurence Rozen ◽  
Hanane El Kenz ◽  
Sophie Huybrechts ◽  
...  

Abstract Chronic transfusion in sickle cell disease (SCD) remains the gold standard therapy for primary and secondary stroke prevention and is indicated for patients with recurrent severe vaso occlusive crisis (VOC) or acute chest syndrome (ACS). Automatized apheresis (AA) has several advantages compared to manual exchange transfusion (MET): shorter procedure, continuous control of fluid balance, etc. The aim of our study was to assess the safety and efficacy of AA in SCD patients previously treated with MET at Hôpital Universitaire des Enfants Reine Fabiola, Brussels, Belgium and to evaluate the change of the costs related to transfusion and chelation overtime. From January 2012, the AA program for SCD patients started in our institution. Patients on chronic transfusion program (CTP) and previously treated with MET were eligible to switch to AA if sufficient peripheral venous access to allow AA without the use of central venous line and if weight ≥ 30kg. On CTP, target HbS was <30% in case of stroke risk and <50% for other indications. Data on biological values, duration of the procedure, intervals between procedures as well as adverse events were recorded for the last 6 months on MET and compared to the data on AA. The overall costs of last year on MET, 1st year and 2nd year on AA were analysed. The cost of packed red blood cell (RBC), one-day care facility, apheresis kit and chelation were recorded. For patients on AA for less than 2 years, costs for the 2nd year were extrapolated taking into account the data from the 6 previous months. Data were collected for this analysis until June 2014. Friedman test was used to compare treatment across years and Dunn's Multiple Comparison Test to compare each year of treatment among them. Ten patients switched from MET to AA at a median age of 11.8 years (range, 9.6-16.8y). The median duration of MET before start of AA was 1.9 years (range 0.5-4.4y). The median duration of AA was 1.7 years (range 1-2.4y). Four patients are on AA for > 2 years, 4 ≥ 20 months and 2 > than 12 months. Indications for CTP were overt stroke (2), pulmonary hypertension (2), recurrent VOC/ACS (5) and poorly tolerated severe anemia (1). All patients remained stable without any SCD related event, except one child who presented seizures without evidence of new stroke and for whom anticonvulsivant therapy was resumed. HbS level remained in the target values for all patients despite a slightly but significantly higher value on AA. The ferritin level and the duration of the procedure decreased significantly (Table 1). The 2 patients on iron chelation stopped it after 10 and 1 AA procedures. Interval between 2 AA was significantly longer than on MET (P<0.0001). On 181 procedures, 9 adverse events (4.9%) required medical intervention: transient hypotension (1), symptomatic hypocalcemia (2), transient headache (2), fever (1), nausea-vomiting (1) and abdominal pain (2). On AA, the requirement of packed RBC was significantly higher than on MET. During the 1st year, costs of AA were significantly higher than MET (132937€ vs.107560€; P=0.01). Nevertheless, during the 2nd year of treatment, the costs of AA were not significantly different from those on MET (102965€ vs. 107560€). Indeed chelation could be stopped in patients previously treated. AA is useful and safe for SCD patients requiring exchange transfusion program. It is less time consuming for nurses and patients, improves iron overload and interval between 2 procedures is significantly reduced. Despite higher costs related to the increase packed RBC requirement, the costs of AA and MET in the Belgian Health Care System are the same as chelation could be stopped in previously treated patients. Abstract 4091. Table 1.Changes in age, weight, biological data and procedure parameters on MET and on AA On METOn AAP value 1st year 2nd yearMedianRangeMedianRangeMedianRangeMedian age (years)11,89,7-16,812,810,8-17,713,311,8-18,6<0,0001Median weight (kg)45,530,4-66,349,933,8-72,05336,1-76,0<0,0001Median height (cm)153,5138-178161143-180165145-182<0,0001Hb (g/L)9,958,6-10,89,958,8-10,6109,2-11,7NSHb S (%)33,525-424028,5-424631-480,0002Ferritin (µg/L)666182-151225552-8111489-622<0,001Duration of procedure (min)245195-36087,375,5-1269164-1540,0002Interval between procedures (d)2821-293428-35,54228-42<0,0001Packed RBC requirement (ml/kg)18,315,1-2032,227,4-36,13026,8-36<0,0001Packed RBC requirement (unit)39,515-796749-12065,538-137<0,0001 Disclosures No relevant conflicts of interest to declare.


2010 ◽  
Vol 10 (1) ◽  
pp. 68-69 ◽  
Author(s):  
Frank Edwin ◽  
Ernest Aniteye ◽  
Martin Tamatey ◽  
Kwabena Frimpong-Boateng

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