scholarly journals Association of Endothelial Biomarkers with Cerebral MRI Perfusion Analysis in Patients with Sickle Cell Disease

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 1000-1000
Author(s):  
Liza Afzali-Hashemi ◽  
Lena Vaclavu ◽  
Erfan Nur ◽  
Aart J Nederveen ◽  
Bart J. Biemond
Keyword(s):  
Sickle Cell Disease ◽  
Sickle Cell ◽  
Adhesion Molecule ◽  
Plasma Levels ◽  
Cerebral Perfusion ◽  
Endothelial Activation ◽  
Healthy Controls ◽  
Standard Laboratory ◽  
Cell Disease ◽  
Laboratory Parameters

Introduction Sickle cell disease (SCD) is associated with silent cerebral infarcts (SCI) which are related to neurocognitive damage. One of the major causes of SCI is the impaired cerebral oxygenation, which makes cerebral blood flow (CBF) an essential parameter to measure. Previous hemodynamic studies have shown elevated CBF and reduced cerebrovascular reserve (CVR) in patients with SCD (Helton 2015; Václavů 2018). CVR is known as the increase of CBF in response to vasoactive stimulus, relative to the baseline. The reduced CVR renders SCD patients susceptible to cerebral ischemia, especially under hypotensive or hypoxic conditions. Possible factors contributing to microvascular damage and thus reduced CVR include hemoglobin S polymerization, neutrophil activation and endothelial activation and adhesion. Previous studies examined the role of these factors in patients with SCD (Sins 2017; Al Najjar 2017). However, the association between the endothelial biomarkers and hemodynamic parameters is unknown in adult patients with SCD. In this study, we investigated the correlation between CBF and CVR and the adhesion molecules including sVCAM-1, sP-selectin, VWF-Ag and ADAMTS13. Additionally, we studied the association of these endothelial biomarkers with standard laboratory parameters. Methods This study was performed in accordance with the Declaration of Helsinki and was approved by the Review Board of Amsterdam UMC. For this study, 33 steady state patients with SCD (mean age 32.1 ± 10.7, 64% male, 29 HbSS, 4 HbSß) and 10 healthy volunteers (mean age 36,4 ± 15.9, 60% male, 2 HbAS, 8 HbAA) were included. Hematologic laboratory parameters were assessed using standard laboratory procedures. Plasma levels of sVCAM-1 and sP-selectin were determined using ELISA (R&D Systems, USA) and ADAMTS13 and VWF-Ag were measured with the INNOVANCE assay (Siemens Healthcare Diagnostics). For the CBF measurements, pseudo-continuous arterial spin labelling (pCASL) was acquired at 3T MRI (Philips Healthcare, The Netherlands). CBF was measured before and after acetazolamide (vasoactive stimulus) administration and subsequently CVR was calculated using the following equation: CVR = (CBFafter - CBFbefore) / CBFbefore x 100% Plasma levels of endothelial biomarkers were compared between groups using ANOVA test. Correlation between the parameters were measured using single regression model where p<0.05 was considered as statistically significant. Results sVCAM-1 levels and VWF-Ag were significantly higher in SCD patients compared to healthy controls (p < 0.01 and p = 0.01). ADAMTS13 and sP-selectin were not significantly different between the two groups (p = 0.06 and p = 0.33). sVCAM-1 was significantly associated with CBF, and parameters of hemolysis LDH and bilirubin in SCD patients (Fig. 1A and 2C). Negative correlation was observed between sVCAM-1 and hemoglobin (Fig. 1B). The relationship between sVCAM-1 and hemodynamic and laboratory parameters are shown in Table 1. No significant correlation was found between sVCAM-1, hemodynamic and standard laboratory parameters in healthy controls. VWF-Ag, ADAMTS13 and sP-selectin were not significantly associated with hemodynamic MRI parameters. Discussion Our results show elevated sVCAM-1 levels in sickle cell patients, strongly related to CBF. sVCAM-1 is an adhesion molecule and elevated plasma levels are found in patients with endothelial activation due to inflammation or atherosclerosis (Cook-Mills 2013; Cybulsky 2001). Previous studies showed elevated levels in sickle cell disease but no correlation with parameters of cerebral perfusion have been demonstrated yet (Antwi-Boasiako 2018; Kato 2005). The strong correlation with CBF is mostly related to the chronic hemolysis given the association found with hemoglobin levels and markers of hemolysis like LDH and bilirubin. In contrast to sVCAM-1, no such relation was found with other markers of endothelial activation such as VWF activity and sP-selectin levels. No correlation between endothelial markers and the CVR was demonstrated, suggesting that endothelial damage itself may not related to the impaired cerebral vasodilatation in response to a vasoactive stimulus. Conclusion Endothelial adhesion molecule sVCAM-1 showed a strong correlation with CBF and parameters of hemolysis, suggesting a relation between the hemolytic damage of endothelial cells and impaired cerebral perfusion. Disclosures Nur: Novartis Pharmaceuticals: Consultancy.

Platelets From Sickle Cell Disease Individuals Induce Endothelial Activation, Demonstrating ICAM-1 and E-Selectin Adhesion Molecule Expression, Inflammatory Cytokine Production and Activation of NFκB Transcription Factor Gene Expression.

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 2114-2114
Author(s):  
Renata Proença-Ferreira ◽  
Ana Flavia Brugnerotto ◽  
Vanessa Tonin Garrido ◽  
Marilene de Fatima Reis Ribeiro ◽  
Fabiola Traina ◽  
...  
Keyword(s):  
Gene Expression ◽  
Endothelial Cells ◽  
Transcription Factor ◽  
Sickle Cell Disease ◽  
Sickle Cell ◽  
Adhesion Molecule ◽  
Direct Contact ◽  
Endothelial Activation ◽  
Cell Disease ◽  
Gene Encoding

Abstract Abstract 2114 Introduction: Sickle cell disease (SCD) pathophysiology is associated with a hypercoagulable state that may contribute to the initiation and propagation of vaso-occlusion. Increased platelet activation has been described in SCD and SCD platelets may present augmented adhesion to the vascular endothelium, potentially contributing to vaso-occlusion. Aim: This study investigated whether platelets (PLTs) from SCD individuals are able to activate endothelial cells per se. Methods: Human umbilical vein endothelial cells (HUVEC) were cultured (1×106cells/well) on 6-well plates (37°C, 5% CO2). Subsequently, HUVEC were co-cultured in direct contact, or not, with washed PLTs (1×108PLTs/well) from healthy control individuals (CON, n=23) or steady-state SCD patients (SCD, n=47; 26 of which were on hydroxyurea therapy; 20mg/Kg/day) for 4h, 37°C, 5%CO2. After incubation, PLTs were removed; supernatants were reserved for cytokine quantification by ELISA, and HUVEC were analyzed by flow cytometry for CD62E (E-Selectin) and CD54 (ICAM-1) surface expression; gene expressions of ICAM1 and NFKBIA were analyzed by qPCR. Results: Basal ICAM-1 expression on the surface of HUVEC (39.6±3.2%, n=15) was significantly increased following their incubation in direct contact with SCD PLTs (46.1±3.1%, n=26, p<0.05, Wilcoxon test), but not CON PLTs (41.3±4.7%, n=12). E-selectin expression was also low level on the surface of HUVEC (0.9±0.2%, n=17), and was slightly but significantly increased following incubation of cells with SCD PLTs (6.1±2.2%, n=26, p<0.001), but not CON PLTs (3.6±1.5%, n=12, p>0.05). Repetition of these assays, but with the placement of transwell inserts in culture plates to separate the PLTs from HUVEC resulted in a 45% decrease in ICAM-1 expression (p<0.05), and 85% decrease in E-selectin (p<0.05) expression on the surface of HUVEC, following their incubation with SCD PLTs. HUVEC produce and release interleukin-8 (IL-8); basal IL-8 production by HUVEC (1×106cells/well) was 1.160±0.187ng/mL (n=21); this production was augmented in the presence of SCD PLTs (1.280±0.149ng/mL, n=42, p<0.01), but not by CON PLTs (1.127±0.157ng/mL, n=23). The influence of PLT IL-8 production on these values was negligible, as shown by data (not shown) demonstrating that PLT IL-8 production is low level and does not differ between CON and SCD PLTs. IL-1β is produced and released by PLTs (CON, 3.4±1.4ρg/mL, n=12; SCD, 6.5±1.5 ρg/mL, n=25, p>0.05), but this production was further increased when PLTs were co-cultured with HUVEC: SCD PLTs (10.3±4.2ρg/mL, n=47; p<0.01) and CON PLTs (5.8±2.4ρg/mL, n=25; p>0.05), compared to HUVEC alone (1.27±0.4ρg/mL, n=24). Gene expression of ICAM1 by HUVEC increased 6.3-fold in the presence of SCD PLTs (n=25, p<0.01), compared to basal expression (n=11), but was not altered in the presence of CON PLTs (n=11, p>0.05). The expression of the gene encoding the NFkB transcription factor, NKBIA, increased 3.4-fold in HUVEC following incubation with SCD PLTs (n=25, p<0.05), compared to basal NFKBIA expression (n=12); however NFKBIA expression in HUVEC was not significantly altered by CON PLTs (n=10, p>0.05). Conclusions: Results indicate that the contact of platelets, or products released from platelets, from patients with SCD may activate endothelial cells, in vitro, increasing adhesion molecule and IL-8 production, associated with an augmented expression of the gene encoding NFkB. Platelets produce IL-1β in greater quantities in the presence of endothelial cells, possibly contributing to endothelial cell activation; however the fact that transwell inserts significantly reduced SCD PLT-mediated endothelial activation indicates that the direct contact of PLTs (possibly via adhesion) is required for this activation. Data indicate that platelets adhered to vessel walls may play an important role in endothelial activation and, therefore, vaso-occlusive mechanisms in SCD. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Tissue factor promotes activation of coagulation and inflammation in a mouse model of sickle cell disease

Blood ◽  
2012 ◽  
Vol 120 (3) ◽  
pp. 636-646 ◽  
Author(s):  
Pichika Chantrathammachart ◽  
Nigel Mackman ◽  
Erica Sparkenbaugh ◽  
Jian-Guo Wang ◽  
Leslie V. Parise ◽  
...  
Keyword(s):  
Endothelial Cell ◽  
Sickle Cell Disease ◽  
Tissue Factor ◽  
Sickle Cell ◽  
Plasma Levels ◽  
Cell Injury ◽  
Vascular Inflammation ◽  
Cell Disease ◽  
Endothelial Cell Injury ◽  
Cell Adhesion Molecule 1

Abstract Sickle cell disease (SCD) is associated with a complex vascular pathophysiology that includes activation of coagulation and inflammation. However, the crosstalk between these 2 systems in SCD has not been investigated. Here, we examined the role of tissue factor (TF) in the activation of coagulation and inflammation in 2 different mouse models of SCD (BERK and Townes). Leukocytes isolated from BERK mice expressed TF protein and had increased TF activity compared with control mice. We found that an inhibitory anti-TF antibody abrogated the activation of coagulation but had no effect on hemolysis or anemia. Importantly, inhibition of TF also attenuated inflammation and endothelial cell injury as demonstrated by reduced plasma levels of IL-6, serum amyloid P, and soluble vascular cell adhesion molecule-1. In addition, we found decreased levels of the chemokines MCP-1 and KC, as well as myeloperoxidase in the lungs of sickle cell mice treated with the anti-TF antibody. Finally, we found that endothelial cell-specific deletion of TF had no effect on coagulation but selectively attenuated plasma levels of IL-6. Our data indicate that different cellular sources of TF contribute to activation of coagulation, vascular inflammation, and endothelial cell injury. Furthermore, it appears that TF contributes to these processes without affecting intravascular hemolysis.

scholarly journals Paraoxonases (PON) 1, 2, and 3 Polymorphisms and PON-1 Activities in Patients with Sickle Cell Disease

Antioxidants ◽  
2019 ◽  
Vol 8 (8) ◽  
pp. 252 ◽  
Author(s):  
Cadiele Oliana Reichert ◽  
Carolina Garcia de Macedo ◽  
Débora Levy ◽  
Bruno Carnevale Sini ◽  
Andréia Moreira Monteiro ◽  
...  
Keyword(s):  
Sickle Cell Disease ◽  
Sickle Cell ◽  
Protective Factor ◽  
Plasma Cholesterol ◽  
Transferrin Saturation ◽  
Density Lipoprotein ◽  
Ldl Oxidation ◽  
Healthy Controls ◽  
Cell Disease ◽  
Q192r Polymorphism

(1) Background: Oxidative stress, chronic inflammation, vasoocclusion, and free iron are all features present in sickle cell disease. Paraoxonases (PON) are a family (PON-1, PON-2, PON-3) of antioxidant enzymes with anti-inflammatory action. Here, for the first time, we described PON-1 activities and PON-1, PON-2, PON-3 polymorphisms in patients with sickle cell disease, homozygous for HbSS, compared with healthy controls. (2) Methods: The groups were matched for age and gender. PON-1 activities (arylesterase and paraoxonase) were determined by enzymatic hydrolysis of phenylcetate and paraoxon, respectively. Polymorphisms were determined by Restriction Fragment Length Polymorphism- Polymerase Chain Reaction (RFLP-PCR). (3) Results: Plasma cholesterol and fractions, ApoA1 and ApoB levels were all decreased in sickle cell disease patients, while anti-oxidized low-density lipoprotein (LDL) antibodies and C-reactive protein were increased. Serum arylesterase activity was lower in sickle cell disease patients when compared with healthy controls. In patients, paraoxonase activity was higher in those with PON-1 RR Q192R polymorphism. In these patients, the increase of serum iron and ferritin levels and transferrin saturation were less pronounced than those observed in patients with QQ or QR polymorphism. No differences were observed with PON-1 L55M, and PON-2 and PON-3 polymorphisms. Multivariate regression analysis showed that transferrin and ferritin concentrations correlated with arylesterase and paraoxonase activities. (4) Conclusions: Both transferrin and ferritin were the main predictors of decreased arylesterase and paraoxonase activities in patients with sickle cell disease. LDL oxidation increased, and RR PON-1 Q192R polymorphism is likely to be a protective factor against oxidative damage in these patients.

scholarly journals Serum Iron Levels and Copper-to-Zinc Ratio in Sickle Cell Disease

Medicina ◽  
2019 ◽  
Vol 55 (5) ◽  
pp. 180
Author(s):  
Charles Antwi-Boasiako ◽  
Gifty Dankwah ◽  
Robert Aryee ◽  
Charles Hayfron-Benjamin ◽  
Alfred Doku ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Sickle Cell Disease ◽  
Sickle Cell ◽  
Serum Levels ◽  
Zinc Homeostasis ◽  
Healthy Controls ◽  
Cell Disease ◽  
Flame Atomic Absorption ◽  
Iron Copper ◽  
Copper And Zinc

Background and Objectives: Altered copper and zinc homeostasis may influence the antioxidant defense system and consequently lead to oxidative stress and associated complications in sickle cell disease (SCD) patients. Iron levels have been reported to increase in sickle cell patients due to frequent blood transfusion, chronic intravenous haemolysis and increased absorption of iron from the gastrointestinal tract. These elevated levels of iron may also lead to extensive oxidative damage. The current study evaluated serum levels of iron, copper and zinc in SCD patients and “healthy” controls. Materials and Methods: The study was a cross-sectional one, comprising 90 SCD patients with Haemoglobin SS and Haemoglobin SC genotypes and 50 HbAA “healthy” controls. Serum levels of iron, copper and zinc were measured using a Flame Atomic Absorption Spectrometer (Variant 240FS manufactured by VARIAN Australia Pty Ltd, VIC, Australia). Copper and zinc ratios were calculated and analyzed. Results: Serum levels of iron and copper were significantly elevated in the SCD patients, compared to their “healthy” counterparts (p < 0.001). These levels were further increased in patients with haemoglobin SS in vaso-occlusive crises (HbSS VOCs). Serum zinc levels were, however, significantly lower in the SCD patients, particularly during vaso-occlusion. The copper-to-zinc ratio was also found to be significantly higher in the SCD patients. Conclusion: Elevated copper-to-zinc ratio may be a biomarker of sickle cell oxidative stress and associated complications. The ratio may also be informative for the management of sickle cell oxidative burden. The significantly lower levels of zinc in the SCD patients may warrant zinc supplementation.

scholarly journals Identification of Clinical and Laboratory Parameters Associated with the Development of Acute Chest Syndrome during Vaso-Occlusive Episodes in Children with Sickle Cell Disease: A Preliminary Step before Assessing Specific and Early Treatment Strategies

2019 ◽  
Vol 8 (11) ◽  
pp. 1839
Author(s):  
Madhi ◽  
Kamdem ◽  
Jung ◽  
Carlier-Gonod ◽  
Biscardi ◽  
...  
Keyword(s):  
Sickle Cell Disease ◽  
Pain Score ◽  
Sickle Cell ◽  
Multivariate Model ◽  
Red Blood Cell Transfusion ◽  
Predictive Score ◽  
Acute Chest Syndrome ◽  
Cell Disease ◽  
Laboratory Parameters ◽  
Increased Risk

This prospective observational study sought to ascertain clinical and laboratory parameters associated with the development of acute chest syndrome (ACS) during vaso-occlusive episodes (VOE) in children with sickle cell disease (SCD). It was performed at the pediatric department of the university Intercommunal Créteil hospital. All children with SCD (all sickle genotypes) consecutively admitted from November 2013 to December 2016 for painful VOEs and no evidence of ACS were included. Clinical and laboratory parameters collected at admission and within 48 h after admission were compared for children in whom ACS developed or not. Variables that were statistically significant on univariate analysis or considered to be clinically relevant were included in a multivariable model to ascertain the risk factors associated with the development of ACS during a VOE. The variables retained in the multivariate model were used to construct a predictive score for ACS. For each included child and during the study period, only data from the first VOE and/or the first ACS were analyzed. Among 191 hospitalizations for painful VOEs, for 176 children with SCD, ACS developed in 35 during hospitalization. Mean hospital stay was longer for children with ACS versus VOEs alone (7.6 (±2.3) vs. 3.3 (±1.8) days, p < 0.0001), and all children with ACS versus 28/156 (17.9%) with VOEs alone received red blood cell transfusion (p < 0.0001). The multivariate model retained pain score (≥9/10), pain localization (abdominal or spinal pain or involving more than two limbs), and high reticulocyte (≥260 × 109/L) and neutrophil (>10 × 109/L) counts, at admission, as independently associated with ACS development. The area under the receiver operating characteristic curve for the ACS predictive score was 0.82 (95% CI: 0.74–0.89), and the negative predictive value was 97.7%. The evolution profiles during the first 48 h differed between children with ACS and VOEs alone, with a more rapid decline of pain score and leucocytosis in children with VOEs. Clinical and laboratory measurements at admission may be simple parameters to identify children with increased risk of ACS development during VOEs and to facilitate early diagnosis of this respiratory complication. Also, the persistent elevation of leukocyte count on day 2 may be considered a sign of evolving ACS.

The Protein C Pathway in Human and Murine Sickle Cell Disease: Alterations in Protein C, Thrombomodulin (TM), and Endothelial Protein C Receptor (EPCR) at Baseline and during Acute Vaso-Occlusion

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 538-538 ◽  
Author(s):  
Yihe Guo ◽  
Teresa Uy ◽  
Nancy Wandersee ◽  
J. Paul Scott ◽  
Hartmut Weiler ◽  
...  
Keyword(s):  
Sickle Cell Disease ◽  
Sickle Cell ◽  
Mouse Liver ◽  
Protein C ◽  
Coagulation System ◽  
Activity Levels ◽  
Healthy Controls ◽  
Cell Disease ◽  
Endothelial Protein C Receptor ◽  
Protein C Activity

Abstract The coagulation system is activated in sickle cell disease (SCD) and acute vaso-occlusion may heighten hypercoagulability. Protein C, a natural anticoagulant, has been reported to be low in individuals with SCD. Therefore, the natural anticoagulation pathway may be disrupted in SCD. The objective of this study is to more fully evaluate the protein C pathway in murine and human SCD by examining levels of: coagulation activation; protein C activity; thrombomodulin (TM); and endothelial protein C receptor (EPCR). In order to assess the level of activation of the coagulation system, we measured plasma thrombin/antithrombin (TAT) complex levels in humans and mice. TAT levels were elevated in 22 humans with SCD versus 9 healthy controls at baseline, and levels increased further in 15 individuals with SCD during acute vaso-occlusive events (5.6±1.2 vs. 2.4±0.2 vs. 9.2±1.8ug/L respectively, p=0.02). In order to study acute vaso-occlusive events in mice, we developed a model of acute vaso-occlusion by exposing Berkeley SCD mice to 3 hours of hypoxia (FI02 8–10%) followed by 2, 4, or 21 hours of reoxygenation in room air (HR2, HR4, HR21). In support of our human findings, TAT was elevated in SCD mice compared to HbA mice at baseline, and increased further in SCD mice exposed to HR2 (n=5–14 per group, p&lt;0.001). Assessment of protein C activity levels in plasma revealed that humans (n=8) with SCD have lower protein C activity levels than healthy controls (n=10) (78%±8.7% vs. 107%±5.3%, p=0.01). Additionally, we are the first to report that protein C activity levels decrease further during acute vaso-occlusive events (paired samples in 7 individuals, p=0.01). Another key protein of the PC pathway is TM, an endothelial-bound protein which activates protein C. TM is elevated in several chronic inflammatory diseases and acutely decreases in meningococcemia. We evaluated TM in mouse liver, an organ susceptible to vascular congestion, infarction, and inflammation in SCD mice. We first measured TM in mouse liver homogenates by ELISA. All SCD mice, at baseline and after HR, expressed elevated liver TM levels compared to HbA mice (n=6 per group, 1.7 to 2.9-fold increases in SCD livers, p&lt;0.05). Exposure to HR in SCD mice increased hepatic inflammation and ischemia and decreased hepatic TM levels compared to SCD mice at baseline (HR2 84%, HR4 60%, and HR21 85% of baseline SCD liver TM). In preliminary experiments, Western Blot analysis confirmed high TM expression in mouse SCD livers compared to HbA livers at baseline and after HR. Immunohistochemistry demonstrated widespread, increased TM staining in hepatic parenchymal vessels of SCD mice compared to HbA mice both at baseline and after HR, with decreased staining within mature infarcts. 4) Finally, we studied EPCR, a membrane-bound protein that binds circulating protein C and promotes both anti-thrombotic and anti-inflammatory functions. Similar to TM, immunohistochemical staining for EPCR was more prominent in hepatic parenchymal vessels of SCD mice compared to HbA mice at baseline and after HR (preliminary studies, n=3 per group). In summary, these data confirm that SCD is a prothrombotic state and suggest that the protein C pathway is altered in SCD. TAT levels are elevated in human and murine SCD, and increase further during vaso-occlusion, illustrating that SCD is a hypercoagulable state. Protein C activity levels are low in human SCD and decrease further during vaso-occlusive events, suggesting that protein C may be consumed both chronically and acutely. In SCD mice at baseline, elevated expression of TM and EPCR suggests that there may be a chronic, compensatory up-regulation of these proteins in SCD. Finally, an acute consumptive process could account for the transient, decreasing trend of these natural anticoagulant proteins in SCD mice after exposure to HR. Thus, targeted administration of activated protein C may provide a novel therapy to minimize tissue injury during acute vaso-occlusive events in SCD.

Hydroxyurea Therapy Increases Expression of BCAM/LU and Adhesion to Laminin in Children with Sickle Cell Disease

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 4806-4806
Author(s):  
Clarissa E Johnson ◽  
Marilyn J. Telen
Keyword(s):  
Extracellular Matrix ◽  
Endothelial Cells ◽  
Sickle Cell Disease ◽  
Adhesion Molecules ◽  
Sickle Cell ◽  
Adhesion Molecule ◽  
Extracellular Matrix Protein ◽  
Published Data ◽  
Adhesion Molecule Expression ◽  
Cell Disease

Abstract Vaso-occlusion is the major cause of morbidity and mortality in sickle cell disease. The tendency of red blood cells (RBCs) to adhere to extracellular matrix molecules and the vascular endothelium is believed to be a significant contributor to the vaso-occlusive process. Some published studies have shown that hydroxyurea decreases sickle (SS) RBC adhesion to some ligands, although the mechanism by which this occurs is not completely understood. SS RBCs demonstrate increased expression of several adhesion molecules, especially BCAM/LU, and also conserve functional signaling pathways that are associated with upregulation of adhesion. BCAM/LU mediates adhesion to the extracellular matrix protein laminin. We hypothesized that patients responsive to hydroxyurea (HU) therapy would exhibit reduced adhesion to laminin as well as a decrease in adhesion molecule expression. Our subjects included patients with Hb SS between the ages of 5 to 18. They were divided into three groups: children not receiving HU therapy (n = 3); children receiving HU therapy for over 6 months (n = 5), and children initially not receiving HU but who were initiating therapy at the time of study enrollment (n = 5). Adhesion to laminin was examined using a graduated height flow chamber to quantitate the adhesion of SS RBCs. Expression of adhesion molecules was analyzed by western blot and densitometry, using monoclonal antibody to BCAM/LU. We found that HU therapy was associated with significantly increased expression of BCAM/LU (HU: 145.8 ± 14.0 SEM; no HU: 60.8 ± 11.0 SEM densitometry units, p = .0014). This somewhat unexpected finding confirms results published earlier this year by Odievre et al. (2008). Adhesion to laminin was also increased for patients on HU (HU: 9.3 ± 5.9; no HU: .3 ± .3, p=.2), although this increase was not significant, given the variability in adhesion seen among patients and the small number of subjects. Nevertheless, the increase in adhesion corresponded to the increase in BCAM/LU expression. In contrast, adhesion to endothelial cells was decreased, although not significantly, in patients on HU (HU: 38.1 ± 38; no HU: 127.2 ± 122.5, p=.6). Our findings thus confirm earlier published data showing that HU increases the expression of BCAM/LU measured by flow cytometry and further shows that this increased expression is associated with increased adhesion to laminin but not to endothelial cells. Potential mechanisms by which HU affects adhesion molecule expression and activity merit further investigation, as does the physiologic role of these alterations. Comparison of results from patient-matched pre-treatment and post-treatment samples should also help define the effects of HU. Figure Figure

Measurement of Urine Pyridinoline and Deoxypyridinoline as Markers of Increased Bone Degradation in Sickle Cell Disease.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 2572-2572
Author(s):  
Erfan Nur ◽  
Willem Mairuhu ◽  
Dees P. Brandjes ◽  
Ton van Zanten ◽  
Bart J. Biemond ◽  
...  
Keyword(s):  
Sickle Cell Disease ◽  
Bone Resorption ◽  
Sickle Cell ◽  
Conflicts Of Interest ◽  
Healthy Controls ◽  
Cell Disease ◽  
Skeletal Involvement ◽  
Asymptomatic Patients ◽  
Bone Degradation ◽  
Painful Crisis

Abstract Abstract 2572 Poster Board II-549 Introduction: Sickle cell disease (SCD) is commonly manifested through skeletal involvement. Besides the characteristic acute musculoskeletal pain, SCD is also associated with chronic skeletal complications such as osteopenia and osteoporosis. During bone resorption, the collagen cross-links pyridinoline (PYD) and deoxypyridinoline (DPD) are released into circulation with subsequent urinary excretion. Measurements of urinary PYD and DPD could serve as valuable tools in detecting osteoporosis in the follow-up of SCD patients but perhaps also in determining the severity of bone infarction during painful crises. Therefore we compared urinary concentrations of PYD and DPD of SCD patients during asymptomatic state and painful crisis with those of race- and age-matched healthy controls. Methods: Urinary concentrations of PYD and DPD, adjusted for urine creatinine, were measured in SCD patients both during asymptomatic state (n=38) and painful crisis (n=27) and healthy controls with normal HbA hemoglobin (n=25) using high performance liquid chromatography (HPLC). Results: PYD and DPD concentrations were higher in asymptomatic SCD patients compared to controls ((54.8 (41.5–68.6) vs. 44.1 (37.7–49.9),P=0.005 and 11.6 (9.3–15.2) vs. 8.5 (6.8–10.4),P=0.004 respectively), with further increments during painful crisis (63.3 (51.8–76.0),P=0.041 and 15.3(13.0–21.5),P=0.003 respectively). In the asymptomatic patients levels of PYD and DPD were significantly correlated to the degree of hemolysis. Conclusion: In sickle cell patients bone resorption is increased and significantly correlated to the degree of hemolysis, compatible with their susceptibility to osteopenia and osteoporosis. Measurement of pyridinoline and deoxypyridinoline could have additional value as biomarkers of osteoporosis in SCD. During painful crises a further increment in bone degradation was observed. Disclosures: No relevant conflicts of interest to declare.

Are There True Non-Responders to Hydroxyurea in Sickle Cell Disease? a Multiparameter Analysis

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 4073-4073 ◽  
Author(s):  
Arati Rani Chand ◽  
Hongyan Xu ◽  
Leigh G Wells ◽  
Betsy Clair ◽  
Cindy Neunert ◽  
...  
Keyword(s):  
Regression Analysis ◽  
Sickle Cell Disease ◽  
Sickle Cell ◽  
Response Rate ◽  
Treatment Time ◽  
Conflicts Of Interest ◽  
Statistical Significance ◽  
Average Dose ◽  
Cell Disease ◽  
Laboratory Parameters

Abstract Hydroxyurea (HU) is the only FDA approved anti-switching agent for the management of sickle cell disease (SCD). The non-response rate to HU (inadequate increase in fetal hemoglobin (HbF)) has been reported to be as high as 30%. However, the role of patient non-compliance as a cause of sub-optimal response to HU has not been studied. Establishing the rate of non-response to HU despite adequate dose and compliance would help in ascertaining patients who might benefit from alternate treatment strategies in SCD. The primary objective of this study was to differentiate between non-compliance and lack of response in patients using laboratory parameters other than HbF. We conducted a retrospective review of 137 adult SCD patients from GRU's Sickle Cell Center that were reportedly taking HU for ≥ 6 months. Data included weight, dose, HbF, Hb, RBC, RDW, retic, MCV, MCH, WBC, ANC, platelets, bilirubin, prior to initiation of HU therapy and at the time of maximal HbF response. Dose of HU/Kg required to achieve that response and time to response was calculated. We defined response as an absolute HbF value of ≥20% or a ≥5% increase in HbF from baseline. The anticipated direction of change in laboratory parameters indicative of compliance was an increase in MCV, MCH, Hb, PCV, and a decrease in RDW, retic count, WBC, neutrophils, platelets, and bilirubin. Patients without a change in HbF but with response from the additional parameters were classified as inadequate-responders. Patients without response in HbF as well as additional parameters were classified as non-compliant. We performed a regression analysis to study the effect of dose and patient age on the response (change in HbF). To model dosage, a new variable called HU exposure was calculated as the product of dose (mg/kg/day) and treatment time (days). The HU exposure and age was used as the predictors for change in HBF. Our results showed that of the 137 patients, 82(59.9%) were responders to HU (mean dose of 18.8mg/kg) with an expected increase in HbF and 36(26.3%) were non-compliant (mean dose of 18.48mg/kg) based on the fact that the aforementioned laboratory values did not change significantly. Only 19(13.9%) were non-responders (mean dose of 16.84 mg/kg) based on a lack of HbF response despite other laboratory parameters being indicative of compliance with HU. Out of the 19 patients who were non-responders only 2 patients were on HU doses more than 20mg/kg. In the overall sample, we found that both age and HU exposure were positively associated with HbF change, which was highly statistically significant (p=2.55E-08 and 7.03E-10, respectively). When we performed regression analysis in the responders, non-responders and non-compliant groups separately we found that in the responder group both age and HU exposure were positively associated with HbF change, with high statistical significance. In the non-responder group however, age and HU exposure were not statistically significant. Patients with SCD on HU who fail to show an adequate increase in HbF are more likely to be non-compliant with medication than actually being truly resistant to it. We have shown that laboratory measurements beside HbF help make the distinction between true HU non-responders and non-compliant patients. We believe a non-response rate of 13.9% may still be too high based on the fact that the average dose of HU was 16.97mg/kg, barely over the recommended starting dose of 15 mg/kg/day. These data suggest that among adult patients on HU, the rates of the non-responders are very low when given adequate doses of HU for sufficient periods of time. Disclosures No relevant conflicts of interest to declare.

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