scholarly journals In vivo survival studies of 51Cr-labeled methyl acetimidate treated erythrocytes in patients with sickle cell disease

Blood ◽  
1980 ◽  
Vol 56 (6) ◽  
pp. 1041-1047 ◽  
Author(s):  
TG Gabuzda ◽  
TL Chao ◽  
MR Berenfeld ◽  
T Gelbart
Keyword(s):  
Sickle Cell Disease ◽  
Survival Time ◽  
Sickle Cell ◽  
Clinical Testing ◽  
Cell Disease ◽  
Show Evidence ◽  
Survival Studies ◽  
Circulating Antibody

Abstract Studies of the survival time of 51Cr labeled erythrocytes treated in vitro with methyl acetimidate (MAI) were conducted in 13 patients with sickle cell disease in order to assess the suitability of this antisickling agent for more extensive clinical testing. In comparison with previously measured control values (average t1/2 8.4 +/- 1.1 days a), the survival time of the treated erythrocytes in 10 of the patients who were not transfused was initially prolonged (average t1/2 24.4 +/- 4.6 days). However, 5 of the 13 patients studied developed circulating antibody against the MAI treated erythrocytes, markedly reducing the survival time of MAI treated erythrocytes in subsequent studies. Two patients, each challenged 3 times with infused MAI treated erythrocytes, failed to show evidence of antibody production, suggesting that not all subjects become immunized even after repeated exposure. In spite of many other promising properties of MAI as an antisickling agent of potential value, consideration of its use in further clinical testing must depend on successful avoidance of immunization in patients receiving infusions of treated erythrocytes.

scholarly journals In vivo survival studies of 51Cr-labeled methyl acetimidate treated erythrocytes in patients with sickle cell disease

Blood ◽  
1980 ◽  
Vol 56 (6) ◽  
pp. 1041-1047
Author(s):  
TG Gabuzda ◽  
TL Chao ◽  
MR Berenfeld ◽  
T Gelbart
Keyword(s):  
Sickle Cell Disease ◽  
Survival Time ◽  
Sickle Cell ◽  
Clinical Testing ◽  
Cell Disease ◽  
Show Evidence ◽  
Survival Studies ◽  
Circulating Antibody

Studies of the survival time of 51Cr labeled erythrocytes treated in vitro with methyl acetimidate (MAI) were conducted in 13 patients with sickle cell disease in order to assess the suitability of this antisickling agent for more extensive clinical testing. In comparison with previously measured control values (average t1/2 8.4 +/- 1.1 days a), the survival time of the treated erythrocytes in 10 of the patients who were not transfused was initially prolonged (average t1/2 24.4 +/- 4.6 days). However, 5 of the 13 patients studied developed circulating antibody against the MAI treated erythrocytes, markedly reducing the survival time of MAI treated erythrocytes in subsequent studies. Two patients, each challenged 3 times with infused MAI treated erythrocytes, failed to show evidence of antibody production, suggesting that not all subjects become immunized even after repeated exposure. In spite of many other promising properties of MAI as an antisickling agent of potential value, consideration of its use in further clinical testing must depend on successful avoidance of immunization in patients receiving infusions of treated erythrocytes.

Hemoglobin Blocks Von Willebrand Factor Proteolysis by ADAMTS-13: A Mechanism Associated with Acquired ADAMTS-13 Deficiency in Patients with Sickle Cell Disease

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 3919-3919
Author(s):  
Zhou Zhou ◽  
Han Hyojeong ◽  
Miguel A. Cruz ◽  
Jose A. Lopez ◽  
Jing-fei Dong ◽  
...  
Keyword(s):  
Sickle Cell Disease ◽  
Sickle Cell ◽  
Von Willebrand Factor ◽  
Elevated Level ◽  
Dependent Manner ◽  
Cell Disease ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract One of the hallmark events of sickle cell disease (SCD) is vasoocclusion and episodic pain crisis. Although the mechanism of vascular occlusion is very complicated, processes like thrombosis and thromboembolism have been recognized to play an important role in the development of such clinical manifestation in SCD. Studies have shown that the von Willebrand factor (VWF), especially the ultra-large (UL) multimers play a major role in vasoocclusion, which clearly indicates a possible impairment of the VWF-cleaving metalloproteae ADAMTS-13 in these patients with SCD. In a recent work, indeed we have mentioned that the plasma ADAMTS-13 in patients with SCD having normal antigen level showed 35% less protease activity than the normal. There may be several plasma factors responsible for the acquired deficiency of ADAMTS-13 in SCD. Since, the increasing evidences suggest that the elevated level of extracellular hemoglobin (Hb) in plasma parallely associated with the pathogenesis of SCD, we investigated the effects of extracellular Hb on VWF proteolysis by ADAMTS-13. We observed that purified Hb dose-dependently inhibited the ADAMTS-13 cleavage of recombinant(r) VWF and endothelial ULVWF multimers under static and flow conditions. Hb bound to VWF multimers in a saturation-dependent manner and more potently to the rVWFA2 domain (affinity Kd~24nM), which contains the cleavage site for ADAMTS-13. Hb bound also to the ADAMTS-13 (Kd~65nM), with 2.7 times less affinity than to VWFA2. The bindings were neither calcium-dependent nor affected by haptoglobin. However, it is the Hb-binding to VWF that prevented the substrate from being cleaved by ADAMTS-13. These in vitro findings are consistent with the in vivo observations in patients with SCD. An elevated level of extracellular Hb in plasma was inversely correlated (linear regression, r2 =0.6354) with the low activity of ADAMTS-13 in a cohort of ten adult patients with SCD (mean±SE, Hb 346±138 mg/l; activity 33.3±30%) compared to age and gender-matched normal individuals (n=10; Hb 24±8 mg/l; activity 76.2±16%). The data together suggest that patients with SCD suffer from acquired ADAMTS-13 deficiency, primarily because Hb competitively binds and inhibits the proteolysis of VWF multimers, leading to ULVWF accumulation on vascular endothelium and in circulation. The Hb-VWF interaction may therefore be considered as a therapeutic target for reducing thrombotic and vasoocclusive complications in patients with severe hemolysis such as those with SCD.

Regulation of Na+/Mg2+ Exchange in Sickle Erythrocytes By Endothelin-1

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 4064-4064
Author(s):  
Pablo A. Rivera ◽  
Yaritza Inostroza ◽  
Jose R. Romero ◽  
Alicia Rivera
Keyword(s):  
Sickle Cell Disease ◽  
Sickle Cell ◽  
Ex Vivo ◽  
Red Cells ◽  
Cell Disease ◽  
Magnesium Homeostasis ◽  
Increased Activity ◽  
Exchange Activity

Abstract Excess levels of endothelin-1 (ET-1), erythrocyte sickling and chronic inflammation have been proposed as important contributors to the pathophysiology of sickle cell disease (SCD). We have shown that ET-1 receptor antagonists improve hematological parameters by reducing Gardos channel activity in two transgenic mouse models of SCD while reducing oxidant stress by decreasing circulating levels of protein disulfide isomerase. Magnesium (Mg2+) deficiency, mediated in part via increased erythrocyte Na+/Mg2+ exchanger activity, has been demonstrated to contribute to erythrocyte dehydration, K+ loss and sickling in SCD. However, the relationship between ET-1 and the Na+/Mg2+ exchanger in SCD remains unclear. We measured Na+/Mg2+ exchange activity in ex vivo red cells and observed increased activity following in vitro incubation of human (2.2 ± 0.2 to 3.2 ± 0.1 mmol/1013 cell x h, P<0.03, n=5) and mouse red blood cells with ET-1 (P<0.001, n=5); events that were significantly blocked by pre-incubation of cells with 1 μM BQ788, a selective inhibitor of ET-1 type B receptors. In addition, in vitro deoxygenation of sickle red cells led to increased exchanger activity that was inhibited by impramine, a Na+/Mg2+ exchange inhibitor, and associated with reduced deoxygenation-stimulated sickle cell dehydration. These results suggest an important role for ET-1 and cellular magnesium homeostasis in sickle cell disease. To this end, we studied Na+/Mg2+ exchange activity in ex vivo erythrocytes from three transgenic sickle mouse models and observed increased activity in these cells when compared to red cells from either Hb A transgenic or C57BL/J6 wild-type mice (P<0.03, n=4). We then tested the in vivo effects of ET-1 receptor antagonists on erythrocyte Na+/Mg2+ exchange activity in the BERK mouse, a transgenic model of SCD. We blocked ET-1 receptors type A and B by in vivo treatment with BQ-788 and BQ-123 (360mg/Kg/Day) for 14 days and observed lower erythrocyte exchanger activity when compared to cells from vehicle treated BERK mice (P<0.02, n=6). Thus our results suggest that ET-1 receptor blockade represents an important therapeutic approach to control erythrocyte volume and magnesium homeostasis that may lead to improved inflammatory and vascular complications observed in SCD. Supported by NIH R01HL090632 to AR. Disclosures No relevant conflicts of interest to declare.

scholarly journals Mycobacterium aviumComplex Infection in a Patient with Sickle Cell Disease and Severe Iron Overload

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Kamal Shemisa ◽  
Nasima Jafferjee ◽  
David Thomas ◽  
Gretta Jacobs ◽  
Howard J. Meyerson
Keyword(s):  
Sickle Cell Disease ◽  
Iron Overload ◽  
Sickle Cell ◽  
Unknown Origin ◽  
Mycobacterial Infection ◽  
In Vivo Studies ◽  
Recurrent Pain ◽  
Cell Disease

A 34-year-old female with sickle cell anemia (hemoglobin SS disease) and severe iron overload presented to our institution with the subacute presentation of recurrent pain crisis, fever of unknown origin, pancytopenia, and weight loss. A CT scan demonstrated both lung and liver nodules concerning for granulomatous disease. Subsequent biopsies of the liver and bone marrow confirmed the presence of noncaseating granulomas and blood cultures isolatedMycobacterium aviumcomplex MAC. Disseminated MAC is considered an opportunistic infection typically diagnosed in the immunocompromised and rarely in immunocompetent patients. An appreciable number of mycobacterial infection cases have been reported in sickle cell disease patients without immune dysfunction. It has been reported that iron overload is known to increase the risk for mycobacterial infection in vitro and in vivo studies. While iron overload is primarily known to cause end organ dysfunction, the clinical relationship with sickle cell disease and disseminated MAC infection has not been reported. Clinical iron overload is a common condition diagnosed in the sub-Saharan African population. High dietary iron, genetic defects in iron trafficking, as well as hemoglobinopathy are believed to be the etiologies for iron overload in this region. Patients with iron overload in this region were 17-fold more likely to die fromMycobacterium tuberculosis. Both experimental and clinical evidence suggest a possible link to iron overload and mycobacterial infections; however larger observational studies are necessary to determine true causality.

scholarly journals Evaluation of persistence and fate of ex vivo edited-HSC modified with donor template and Its role in correcting Sickle Cell Disease

2021 ◽  
Author(s):  
Sowmya Pattabhi ◽  
Samantha N Lotti ◽  
Mason P Berger ◽  
David J Rawlings
Keyword(s):  
Sickle Cell Disease ◽  
Sickle Cell ◽  
Ex Vivo ◽  
Cell Disease ◽  
Gene Correction ◽  
Healthy Human ◽  
Peripheral Blood Stem Cells ◽  
Donor Template

Sickle cell disease (SCD) is caused by a single nucleotide transversion in exon 1 of the HBB gene that changes the hydrophobicity of adult globin (βA), leading to substantial morbidity and reduced lifespan. Ex vivo autologous gene editing utilizing co-delivery of a designer nuclease along with a DNA donor template allows for precise homology-directed repair (HDR). These gene corrected cells when engrafted into the bone marrow (BM) can prove to be therapeutic and serves as an alternative to HLA-matched BM transplantation. In the current study, we extensively explored the role of single stranded oligonucleotide (ssODN) and recombinant adeno-associated 6 (rAAV6) donor template delivery to introduce a codon-optimized change (E6optE) or a sickle mutation (E6V) change following Crispr/Cas9-mediated cleavage of HBB in healthy human mobilized peripheral blood stem cells (mPBSCs). We achieved efficient HDR in vitro in edited cells and observed robust human CD45+ engraftment in the BM of NBSGW mice at 16-17 weeks. Notably, recipients of ssODN-modified HSC exhibited a significantly higher proportion of HDR-modified cells within individual BM, CD34+ and CD235+ compartments of both E6optE and E6V cohorts. We further assessed key functional outcomes including RNA transcripts analysis and globin sub-type expression. Our combined findings demonstrate the capacity to achieve clinically relevant HDR in vitro and in vivo using both donor template delivery method. The use of ssODN donor template-delivery is consistently associated with higher levels of gene correction in vivo as demonstrated by sustained engraftment of HDR-modified HSC and erythroid progeny. Finally, the HDR-based globin protein expression was significantly higher in the E6V ssODN-modified animals compared to the rAAV6-modified animals confirming that the ssODN donor template delivery outperforms rAAV6-donor template delivery.

scholarly journals Sickle cell disease of transgenic SAD mice

Blood ◽  
1994 ◽  
Vol 84 (9) ◽  
pp. 3189-3197 ◽  
Author(s):  
M Trudel ◽  
ME De Paepe ◽  
N Chretien ◽  
N Saadane ◽  
J Jacmain ◽  
...  
Keyword(s):  
Sickle Cell Disease ◽  
Sickle Cell ◽  
Acute Hypoxia ◽  
Oxygen Affinity ◽  
Premature Death ◽  
Cellular Level ◽  
Cell Disease ◽  
Severe Renal Disease

Erythrocyte sickling on deoxygenation in vitro occurs in transgenic SAD mice, hemizygous for a modified human sickle hemoglobin, HbSAD [alpha 2 beta 2S(beta 6val)Antilles (beta 23 lle)D- Punjab (beta 121Gln)] (SAD- 1, 19% HbSAD; beta-thal/SAD-1, 26% HbSAD). The present study examines the cellular defects in vivo and pathologic changes observed in SAD-1 mice at atmospheric oxygenation as well as the effect of acute hypoxia. The transgenic mice showed generalized congestion and microvascular occlusions, occasionally with thrombosis and infarctions of lung, kidneys, penis, and myocardium. The most prevalent chronic organ lesions were congestive splenomegaly (83% of animals) and renal glomerulopathy, which affected 75% of animals by 10 months of age. Further, SAD mice have a mean lifespan that was reduced by 40% when compared with nontransgenic littermates. Premature death of SAD mice was associated with acute vasoocclusive events or severe renal disease. SAD mice developed lethal vasoocclusive processes when exposed to reduced pO2 conditions, whereas control mice survived normally. The sensitivity to hypoxia appears to depend on the cellular level of HbSAD, because death occurred at pO2 of 42 mmHg for SAD mice and 49 mmHg for beta-thal/SAD. Administration of an antisickling agent that increases oxygen affinity (BW12C79) protected SAD and beta-thal/SAD mice from the lethal hypoxic stress. In conclusion, the transgenic SAD and beta-thal/SAD mice developed a pathophysiology that strongly resembles human sickle cell disease. Moreover, this animal model allows studies on the effect of antisickling agents.

scholarly journals Rheological Effects of L-Glutamine in Patients with Sickle Cell Disease

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 3567-3567
Author(s):  
Celeste K. Kanne ◽  
Varun Reddy ◽  
Vivien A. Sheehan
Keyword(s):  
Sickle Cell Disease ◽  
Sickle Cell ◽  
Blood Viscosity ◽  
Whole Blood ◽  
Blood Cells ◽  
Cell Disease ◽  
Phase 3 ◽  
Whole Blood Viscosity

Background: ENDARITM (oral pharmaceutical L-glutamine powder) received FDA approval in 2017 as a treatment for sickle cell disease (SCD). A pivotal phase 3 clinical study conducted by Emmaus Medical, Inc. showed that L-glutamine resulted in a lower incidence of vaso-occlusive crises (VOC) as well as a lower rate of hospitalizations and shorter hospital stays. No changes in standard clinical laboratory values were noted. The clinical improvements associated with sickle cell complications are believed to be due to an increase in the proportion of the reduced form of nicotinamide adenine dinucleotides in the red blood cells (RBC) of patients with SCD, reducing the oxidative stress. While the endpoints in the phase 3 study are clinically important, it is essential that we identify biomarkers or measurable laboratory changes that can serve as endpoints for future clinical trials assessing dose optimization and the efficacy and safety of L-glutamine in SCD individuals, including those with hepatic and renal dysfunction. RBC rheology is markedly abnormal in SCD; blood is more viscous for a given hematocrit than normal individuals, dense red blood cells (DRBC) are packed with HbS, potentiating sickling, and RBCs are less deformable than those of HbAA or HbAS individuals. High whole blood viscosity, high DRBCs, and poor RBC deformability are associated with higher rates of VOC. Given the demonstrated reduction in pain events, we hypothesized that L-glutamine might improve RBC rheology and sought to test this in vitro and in vivo using a battery of rheological tests. Methods: For the in vitro study, 6 mL of whole blood was drawn into an EDTA vacutainer from ten pediatric patients with sickle cell anemia (HbSS or HbSβ0) during routine clinical checkups under an IRB approved protocol. The cohort included 3 female and 7 male patients, ages 2-19 years old. All patients were on a steady dose of hydroxyurea and did not receive a transfusion within the 3 months prior to sample collection. A 200 mM stock solution of L-glutamine and water was mixed and filtered under light-protected conditions. Aliquots were stored at -20°C to avoid multiple freeze/thaw cycles. L-glutamine was added to 3 mL of whole blood for a final concentration of 1 mM (average in vivo L-glutamine plasma concentration in patients with SCD treated with L-glutamine); 3 mL of the same patient sample with water added served as a control. After a 24-hour incubation period at 4°C, whole blood viscosity was measured using a cone and plate viscometer at 37°C (DV3T Rheometer, AMETEK Brookfield, USA), %DRBCs were measured on an ADVIA 120 Hematology System (Siemens Healthcare Diagnostics, Inc., USA), and deformability measured using a Laser Optical Rotational Red Cell Analyzer (Lorrca®) (RR Mechatronics, the Netherlands) with the Oxygenscan module. The Oxygenscan measures RBC deformability at normoxia (Elmax), deformability upon deoxygenation (EImin), and point of sickling (PoS), the oxygen tension at which deformability begins to decline, reflecting the patient-specific pO2 at which sickling begins. Paired samples (with and without added L-glutamine) were analyzed using Student's t-test. For the in vivo study, rheological tests were performed on peripheral blood from one patient (18-year-old male on hydroxyurea) at baseline and treated with L-glutamine as part of his routine clinical care. Results and conclusions: Addition of L-glutamine in vitro significantly reduced the PoS, meaning RBCs incubated with L-glutamine could tolerate a lower pO2 before sickling compared to the control. RBCs incubated with L-glutamine also had significantly higher EImin, meaning deoxygenated RBCs were more flexible and deformable. Whole blood viscosity at 45s-1 and 225s-1 did not change significantly following incubation with L-glutamine; %DRBCs also did not change significantly (Table 1). The in vivo patient sample tested exhibited a similar improvement in PoS and EImin (Figure 1). We therefore propose to further test the performance of the PoS and EImin as possible biomarkers of response to L-glutamine in vivo. If validated, these biomarkers may also help further elucidate the mechanisms of action of L-glutamine in SCD. Disclosures No relevant conflicts of interest to declare.

Hemoglobin S Exhibits Distinct MRI Oximetry Calibration in Vitro

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 4842-4842
Author(s):  
Adam M Bush ◽  
Thomas D. Coates ◽  
John C Wood
Keyword(s):  
Sickle Cell Disease ◽  
Oxygen Saturation ◽  
Sickle Cell ◽  
Model Fit ◽  
Oxygen Extraction Fraction ◽  
Cell Disease ◽  
Extraction Fraction ◽  
Gray Circle

Abstract Cerebral oxygen extraction fraction (OEF) is a powerful biomarker that could be used to stratify cerebrovascular morbidity in patients with sickle cell disease (SCD). Recently, several MRI intravascular oximetry techniques have demonstrated early feasibility in non-invasively quantitating OEF. Critical to this technique is the use of empirically derived calibrations that convert the measured magnetic relaxation property, T2, into oxygen saturation. Previous work demonstrated a strong hematocrit and saturation dependence on T2 and our prior work extended early results to hematocrit ranges common in patients with chronic anemia1. Despite improvements in calibration models, it remains an unanswered question whether the unique hemorheologic properties of hemoglobin S (HbS) containing red cells will give rise to fundamentally distinct magnetic properties compared to healthy, hemoglobin A (HbA) cells. Methods: All studies were performed on at CHLA under an IRB protocol with consent/assent. The blood of 11 subjects with sickle cell disease were studied (6 Male, 5 Female, aged 25.4 ± 14.5 years). Six had HbSS, three had HbSC, and two had HbSB0). Three of the subjects were on chronic transfusion therapy (2HbSS, 1 HbSB0). Two tablespoons of blood was drawn for the antecubital vein and stored at 4°C until analysis. For analysis, blood was placed in a custom built imaging apparatus and heated to 37° C. Oxygen level was measured with a hemoximeter and T2 was measured within a 3T Philips scanner. Following the T2 measurement blood was removed from the imaging apparatus and desaturated in a temperature controlled chamber using a membrane oxygenator and 5% CO2 and 95% N2 gas mixture. MRI T2 measurements and deoxygenation were repeated until a blood saturation level of ~30% was reached. T2 was measured with a phase cycled, CPMG sequence with 0, 4, 8 16 inversions pulse and a tau of 10ms. Monoexponetial fitting was used to derive T2. Results: Our previous work using a similar system and HbA blood demonstrated a highly reproducible relationship linking T2 to hematocrit and oxygen saturation (Y) as follows: R2= 1/T2 = A1*HCT*(1-Y)2 + A2*(1-Y)2 + A3*HCT + A4 where the coefficients A1, A2, A3, and A4 were fit to data from a broad range of hematocrit and oxygen saturation values. In blood from sickle cell patients, we found that the A1 and A3 terms were zero. Thus the calibration curve was essentially independent of hematocrit. Figure 1 shows the tight relationship between hematocrit and 1/T2 for HbA could not be reproduced in HbS blood. In Figure 2, 1/T2 maintained a tight relationship (R2=.981) with (1-Y)2. The slope of 1/T2 and (1-Y)2was higher in HbS blood compared to HbA. There was also a positive relationship between HbS% and the residual of (1-Y)2 and R2 however this is was a weak effect (R2=0.057). Discussion: We found that the T2 of HbS containing red cells is distinct from the healthy HbA containing cells. This work has clinical implications for intravascular MRI oximetry performed in patients with sickle cell disease2 in that neglecting the magnetic differences between HbA and HbS may result in a 9.5%± 2.8% average bias in absolute saturation at a HCT of 32% . Interestingly, we were unable find a difference across sickle phenotypes and only small differences in transfused vs nontransfused patients. We suspect that irreversibly sickled cells, even few in number, will greatly influence the local magnetic field and shorten the T2 of sickle blood. It remains to be shown whether the in vitro conditions of this experiment are applicable to in vivo condition more broadly. In-vivo cross-validation studies are ongoing. 1). Bush et al. MRM 2016 2). Jordan LC et al. Brain 2016 Jordan LC, Gindville MC, Scott AO, et al. Non-invasive imaging of oxygen extraction fraction in adults with sickle cell anaemia. Brain 2016;139(Pt 3):738-5 Figure 1 Light gray circle designate HbA samples and dark gray squares correspond to HbS. There was a tight linear relationship between HCT and 1/T2 in HbA cells that was not present in HbS cell. Figure 1. Light gray circle designate HbA samples and dark gray squares correspond to HbS. There was a tight linear relationship between HCT and 1/T2 in HbA cells that was not present in HbS cell. Figure 2 Light gray line designates previously published HbA model fit and dark gray squares correspond to HbS. 1/T2 was linearly dependent on (1-Y)2in HbS blood however the slope of this relationship was higher when compared to known relationship with HbA. Figure 2. Light gray line designates previously published HbA model fit and dark gray squares correspond to HbS. 1/T2 was linearly dependent on (1-Y)2in HbS blood however the slope of this relationship was higher when compared to known relationship with HbA. Disclosures Wood: World Care Clinical: Consultancy; Celgene: Consultancy; World Care Clinical: Consultancy; Vifor: Consultancy; Vifor: Consultancy; Ionis Pharmaceuticals: Consultancy; Ionis Pharmaceuticals: Consultancy; Celgene: Consultancy; AMAG: Consultancy; AMAG: Consultancy; Apopharma: Consultancy; Apopharma: Consultancy; Biomed Informatics: Consultancy; Biomed Informatics: Consultancy.

scholarly journals Hypoxia Enhanced Red Cell Adhesion in Vitro May Identify Patients at Risk for Vasculopathy

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 3672-3672
Author(s):  
Charlotte Yuan ◽  
Erina Quinn ◽  
Sargam Kapoor ◽  
Myeongseop Kim ◽  
Erdem Kucukal ◽  
...  
Keyword(s):  
Sickle Cell Disease ◽  
Sickle Cell ◽  
Research Funding ◽  
Cell Disease ◽  
Hypoxic Conditions ◽  
Significant Difference ◽  
History Of ◽  
Male Subjects

Abstract Background: Priapism is a serious complication associated with Sickle Cell Disease (SCD) that may be a manifestation of underlying vasculopathy. The Centers for the Study of Complex Diseases of Childhood (CSCCD), comprising independent Comprehensive Sickle Cell Centers, demonstrated an association of priapism with hemolysis.1 Previously, we identified two groups of people with SCD based on red blood cell (RBC) adhesion under hypoxic conditions: those patients whose RBCs showed hypoxia-enhanced adhesion (HEA) and those whose did not (non-HEA).2 Patients with HEA had evidence for more hemolysis in vivo. Here, we aimed to examine (1) the association of HEA with hypoxia in vivo, and (2) RBC adhesion in normoxic and hypoxic conditions in male patients with or without a history of priapism. Methods: This retrospective study was conducted at the Adult Sickle Cell Disease Clinic at the University Hospitals Seidman Cancer Center, in Cleveland, OH between 2015 to 2018. Blood samples were obtained from 26 male subjects (29 samples, 25 HbSS and 1 HbSS HPFH). Adhesion experiments were performed as previously reported by passing surplus whole blood through LN-immobilized microchannels at physiological conditions under both normoxic and hypoxic conditions.2,3 Adherent RBCs were then quantified with microscope after a wash step. The median value was used for data analyses from multiple samples obtained from an individual. Chart review was conducted to examine results of hypoxia testing obtained in vivo as part of routine clinical care. Results: Male subjects with HbSS and a history of priapism had higher HEA in comparison to subjects without a history of priapism (3268 ± 5647 vs. 122 ± 1218, p=0.016). However, there was no significant difference between RBC adhesion of the two groups under normoxic conditions (529 ± 1528 vs. 402 ± 280). More male subjects with priapism had hypoxia in vivo (10 out of 14) than subjects without priapism (5 out of 12). Compared to male subjects with a history of priapism, those without a history of priapism had lower lactate dehydrogenase levels (474 ± 267 vs. 290 ± 215, p=0.008). Conclusions: Our data showed that subjects with a history of priapism had a higher HEA and tended to have more evidence for hypoxia in vivo than did subjects without a history of priapism. Further, male subjects with hypoxia in vivo had more HEA than did those without hypoxia in vivo (not shown). Hypoxia in vivo may cause increased RBC damage (reflected by HEA), hemolysis, nitric oxide depletion, and consequent vasculopathy, resulting in priapism. Hypoxia may be treatable, when identified in subjects with a history priapism in vivo or possibly with HEA in vitro. This could plausibly modify disease severity in some cases. References: Nolan VG, Wyszynski DF, Farrer LA, Steinberg MH. Blood. 20015 Nov;106(9):3264-7. doi: 10.1182/blood-2005-04-1594 Kim M, Alapan Y, Adhikari A, Little JA, Gurkan Microcirculation. 2017 Jul;24(5). doi: 10.1111/micc.12374. Alapan Y, Kim C, Adhikari A, Gray KE, Gurkan-Cavusoglu E, Little JA, Gurkan Transl Res. 2016 Jul;173:74-91.e8. doi: 10.1016/j.trsl.2016.03.008. Epub 2016 Mar 19. Disclosures Little: NHLBI: Research Funding; PCORI: Research Funding; Hemex: Patents & Royalties: Patent, no honoraria; Doris Duke Charitable Foundations: Research Funding.

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